CN110721553A - System and method for removing heat-stable salt from organic amine liquid - Google Patents

Abstract

The invention relates to the field of organic amine liquid purification, and discloses a system for removing thermally stable salts in organic amine liquid and a method for treating organic amine liquid by using the system. The system includes: an organic amine solution storage device, an electrode solution storage device, a demineralized water storage device and a membrane stack, the membrane stack is respectively connected with the organic amine solution storage device, the electrode solution storage device and the demineralized water storage device They are arranged in communication with each other, and form an organic amine liquid circulation loop, an electrode liquid circulation loop and a demineralized water circulation loop respectively, and the system also includes a conductivity meter and a control center, and the control center is used to receive the conductance from the conductivity meter. According to the conductivity signal of the conductivity meter, the circulating flow of the organic amine liquid circulation loop and the desalted water circulation loop, and the recycling and discharge of the organic amine liquid and waste liquid are adjusted. When the system treats organic amine liquid, it can simultaneously remove anions and cations in the amine liquid, reducing the consumption of alkali liquid and the discharge of waste liquid.

Description

System and method for removing heat-stable salt from organic amine liquid

technical field

The invention relates to the field of organic amine liquid purification, in particular to a system for removing thermally stable salts in organic amine liquids and a method for using the system to treat organic amine liquids containing thermally stable salts.

Background technique

In the petrochemical field, there are many raw gas containing a large amount of acid gas, such as carbon dioxide (CO ₂ ), hydrogen sulfide (H ₂ S), sulfur dioxide (SO ₂ ), etc., and these acid gases need to be removed before entering the next step. Process flow.

The organic amine method is widely used to remove acid gas from natural gas, liquefied gas and flue gas. Among them, commonly used organic amines include ethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), triethanolamine, N-methylethylenediamine, diisopropanolamine, N,N-diethanolamine Butylethanolamine, ethylenediamine, diethylamine, tetramethylethylenediamine, piperazine, etc. However, in the process of cyclic removal of acid gas, the degradation and oxidation of organic amines during high-temperature regeneration, inorganic salts carried in the gas, and strong acidic substances in the gas will lead to an increase in the content of thermally stable salts in organic amines. The improvement of thermally stable salts will cause problems such as foaming of organic amine liquids and pipeline corrosion, and further promote the degradation and deterioration of amine liquids, forming a vicious circle, resulting in a decline in the ability of amine liquids to remove acid gas or even unusable. A large amount of waste amine solution needs to be disposed of every year, which not only costs huge amount of disposal, but also causes waste of resources.

In order to solve the above problems, in the prior art, the desulfurized amine solution is usually filtered and then purified by an ion exchange method.

For example, CN102125803A discloses a method for purifying inferior amine liquid. The method includes the following steps: (1) Filtration of solid impurities: filtering a medium in a fixed bed, and filtering the solid impurities in inferior amine liquid, wherein the filtering The medium is one or more of molecular sieve, activated carbon and ion exchange membrane; (2) exchange and removal of acid ions: the mixed resin is packed in the ion exchange column, and the filtered amine liquid is passed through the mixed ion exchange column. Exchange resin, realize the exchange and removal of acid ions at a space velocity of 1-50h ^-1 and a temperature of 10-50℃; (3) Regeneration of filter medium and exchange resin: the pressure drop of amine liquid passing through the filter medium is too high , when the space velocity is too low, the regeneration or replacement of the filter medium is carried out to facilitate the smooth filtration of the amine liquid and reduce the filtration time; when the pH value of the amine liquid at the inlet and outlet of the ion exchange resin tower is close to The regeneration space velocity of the exchange resin is 1-50h ^-1 and the temperature is 10-50°C; the regenerated resin is recycled.

However, when the amine solution is treated by the above method, usually only solid particles and thermally stable salt anions can be removed, but cations (such as Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ ) in the amine solution cannot be removed. Wait). Moreover, the ion exchange method will consume a large amount of alkaline solution (such as NaOH), and discharge a large amount of strong alkaline wastewater. The COD is very high and cannot be effectively treated at this time.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of large consumption of chemical agents, large waste liquid discharge and difficulty in removing cations in the existing ion exchange technology for removing thermally stable salts from amine liquids, and to provide a method for removing thermally stable salts from organic amine liquids. Salt system and method for processing organic amine liquid containing thermally stable salt using the system, the system has strong desalination ability, is suitable for processing a variety of organic amine liquids containing different thermally stable salt types, is easy to assemble, highly automated, saves money Labor costs. Using the system to treat organic amine liquid containing thermally stable salts can not only achieve simultaneous removal of anions and cations in the amine liquid with a high removal depth, but also greatly reduce or not consume lye, with low waste liquid discharge and enhanced Repeatable service life of organic amine solutions.

In order to achieve the above object, one aspect of the present invention provides a system for removing thermally stable salts from an organic amine solution, the system comprising: an organic amine solution storage device, an electrode solution storage device, a demineralized water storage device, a membrane stack and a control center, Wherein, the membrane stack is respectively connected with the organic amine solution storage device, the electrode solution storage device and the demineralized water storage device; the membrane stack is provided with at least one organic amine solution inlet, organic amine solution outlet, and waste liquid inlet, waste liquid outlet, electrode liquid inlet and electrode liquid outlet; the organic amine liquid outlet and the waste liquid outlet are respectively provided with a first conductivity meter and a second conductivity meter for monitoring the organic amine The liquid conductivity at the liquid outlet and the waste liquid outlet; a first regulating valve is provided on the material conveying pipeline between the organic amine liquid outlet and the organic amine liquid storage device, and the demineralized water storage device A second regulating valve is provided on the material conveying pipeline between the waste liquid inlet; the system further includes a control center for receiving conductivity signals from the first conductivity meter and the second conductivity meter , and adjust the opening of the first regulating valve and the second regulating valve according to the conductivity signals of the first conductivity meter and the second conductivity meter.

The second aspect of the present invention provides a method for treating an organic amine solution containing a heat-stable salt by using the aforementioned system for removing heat-stable salts from an organic amine solution, the method comprising introducing the organic amine solution to be treated into the The organic amine solution storage device of the system, the demineralized water is introduced into the demineralized water storage device of the system, the electrode solution is passed into the electrode solution storage device, and then the organic amine solution is circulated and pumped into the amine of the membrane stack. a liquid chamber, wherein the demineralized water in the demineralized water storage device is circulated and pumped into the waste liquid chamber of the membrane stack, and the electrode solution in the electrode solution storage device is circulated and pumped into the anode chamber and the cathode chamber of the membrane stack respectively; The anode plate and the cathode plate of the membrane stack are respectively connected to the positive electrode and the negative electrode of the power supply, and the organic amine solution to be treated that is circulated and pumped into the membrane stack is subjected to heat-stable salt removal treatment to obtain an organic amine solution for removing heat-stable salts. The amine solution and the demineralized water enriched with thermally stable salts, when the obtained organic amine solution from which thermally stable salts have been removed and the demineralized water enriched with thermally stable salts meet the recycling and discharge standards, respectively, the thermally stable salts removed after the treatment is processed. The organic amine liquid is transported to the organic amine liquid reuse system, and the demineralized water enriched with thermally stable salt obtained after the treatment is discharged to the outside of the system as a waste liquid.

Existing methods for removing thermally stable salts from amine liquids rarely involve the removal of cations. However, after cations accumulate in organic amines to a certain extent (such as exceeding 1000 ppm), the desulfurization efficiency of desulfurized organic amine liquids will be greatly affected. . For example, when an amine solution containing a large amount of sodium ions is used to remove hydrogen sulfide from liquefied gas, the hydrogen sulfide content in the lean amine solution will increase, the desulfurization depth of the liquefied gas will decrease, or even the sulfur content of the liquefied gas after desulfurization will exceed the standard. Its hazard even exceeds that of thermostable salt anions. According to the conventional theory, the amine liquid itself should easily interact with the cation exchange resin in the aqueous solution. Therefore, if the cation exchange resin is used to remove the cations, a competitive exchange relationship will be formed in the process of removing the cations, resulting in a large amount of the amine liquid itself. Loss is not conducive to industrial production, therefore, how to effectively remove the cations in the amine solution has always been a technical problem in the art. In order to avoid the influence caused by excessive cation content, the current common method is to replace the fresh organic amine and discharge the seriously deteriorated organic amine, but this will lead to increased operating costs, environmental pollution and waste of resources.

After in-depth research, the inventors of the present invention found that, under the action of electrodialysis, the organic amines containing thermostable salts can make the charged particles in the thermostable salts migrate directionally, enter different compartments, and continuously perform separation, concentration and purification. removal, so as to realize the purification of organic amine liquid. However, with the progress of the purification process, the thermally stable salt concentration in the organic amine solution decreases, and the electrical conductivity of the organic amine solution will gradually decrease. In theory, when the thermally stable salt concentration decreases to 0 or close to 0, the organic amine solution There are almost no movable charged particles in the organic amine solution, resulting in low conductivity of the organic amine solution. In the process of electrodialysis, the decrease of the conductivity of the organic amine liquid in the amine liquid chamber will lead to serious consequences, such as: (1) The organic amine liquid is ionized and enters the demineralized water compartment, resulting in the loss of the organic amine liquid, and further desalination cannot be completed. ; (2) The current efficiency will be reduced, and the electrical energy will be further converted into thermal energy, resulting in an increase in the temperature of the organic amine solution, causing irreversible damage to the ion exchange membrane. In order to solve this problem, the inventors of the present invention found that when the amine liquid compartment of electrodialysis is filled with ion exchange resin, when the conductivity of the organic amine liquid decreases or even fails to conduct electricity, the ion exchange resin acts as a conductive medium, which can It can effectively promote the electrodialysis process and improve the desalination efficiency of electrodialysis. In addition, setting a control center in the system can realize the fully automatic removal of the thermally stable salt removal process in the organic amine solution. When the recovery and discharge standards are met, the organic amine liquid recovery and/or waste liquid discharge can be automatically carried out. After the organic amine liquid recovery and/or waste liquid discharge, the system automatically replenishes the organic amine liquid and/or demineralized water without manual labor. Intervention, which greatly saves labor costs. Therefore, the system provided by the present invention has a high removal depth of thermally stable salts in the organic amine liquid, a high degree of automation, effectively reduces the operation cost, and improves the desulfurization efficiency of the organic amine liquid.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Description of drawings

Fig. 1 is when the membrane stack is the yin-yang membrane stack and adopts the thermally stable salt removal system in the organic amine solution provided by the present invention to process the organic amine solution containing the thermally stable salt;

FIG. 2 is a schematic diagram of the structure and working principle of the bipolar membrane stack in the present invention.

Description of reference numerals

1. Organic amine solution storage device 2. Electrode solution storage device 3. Demineralized water storage device

4. Membrane stack 5. Control center 61. First regulating valve

62, the second regulating valve 63, the third regulating valve 64, the fourth regulating valve

65, the fifth control valve 66, the sixth control valve 67, the seventh control valve

71. Organic amine liquid circulating pump 72. Electrode liquid circulating pump 73. Demineralized water circulating pump

81. Organic amine liquid level meter 82. Demineralized water level meter 91. The first conductivity meter

92. The second conductivity meter A, the first ion exchange membrane B, the second ion exchange membrane

C, the third ion exchange membrane I-1, the anode compartment I-2, the cathode compartment

II, amine liquid chamber III, waste liquid chamber

Detailed ways

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

A first aspect of the present invention provides a system for removing thermally stable salts from organic amine solution. As shown in FIG. 1 , the system includes: an organic amine solution storage device 1, an electrode solution storage device 2, a demineralized water storage device 3, a membrane stack 4 and control center 5, wherein the membrane stack 4 is respectively connected to the organic amine solution storage device 1, the electrode solution storage device 2 and the demineralized water storage device 3; the membrane stack 4 is provided with at least one Organic amine liquid inlet, organic amine liquid outlet, waste liquid inlet, waste liquid outlet, electrode liquid inlet and electrode liquid outlet; the organic amine liquid outlet and the waste liquid outlet are respectively provided with a first conductivity meter 91 and The second conductivity meter 92 is used to monitor the liquid conductivity at the outlet of the organic amine liquid and the outlet of the waste liquid; the material transportation between the outlet of the organic amine liquid and the storage device 1 of the organic amine liquid A first regulating valve 61 is arranged on the pipeline, and a second regulating valve 62 is arranged on the material conveying pipeline between the demineralized water storage device 3 and the waste liquid inlet; the system also includes a control center 5 for Receive the conductivity signal from the first conductivity meter 91 and/or the second conductivity meter 92, and adjust the conductivity according to the conductivity signal of the first conductivity meter 91 and/or the second conductivity meter 92 The opening of the first regulating valve 61 and/or the second regulating valve 62 .

According to the present invention, the control center 5 is preferably an automatic control device and the human-machine interface interaction is realized by programmable software, and the control center 5 can The conductivity signal changes, and the opening of the first regulating valve 61 and/or the second regulating valve 62 is automatically adjusted, so as to realize automatic monitoring and control of the flow and circulation of the organic amine solution to be treated and/or the desalted water. and emission frequency.

According to the present invention, preferably, the control center 5 can set the conductivity signal difference value or conductivity signal value of the organic amine solution according to the actual situation, when the conductivity signal difference value measured by the first conductivity meter 91 Or the conductivity signal value reaches the set conductivity signal difference value or the set conductivity signal value, indicating that the organic amine liquid to be treated has reached the desalination standard, and the No. The three regulating valve 63 outputs the treated organic amine liquid that meets the standard to the organic amine liquid reuse system.

According to the present invention, as shown in FIG. 1 , the membrane stack 4 includes an anode plate and a cathode plate oppositely disposed at both ends of the membrane stack 4 , and a mold containing a plurality of ion exchange membranes disposed between the anode plate and the cathode plate. group; the area between the anode plate and the module forms an anode chamber I-1, and the area between the cathode plate and the module forms a cathode chamber I-2; the plurality of ion exchange membranes are in The module is divided into a plurality of periodically alternately arranged amine liquid chambers II and waste liquid chambers III; the ion selective permeability of two adjacent ion exchange membranes are different; in each of the amine liquid chambers II The organic amine liquid inlet and the organic amine liquid outlet are arranged on the opposite side of each of the waste liquid chambers III, and the waste liquid inlet and the waste liquid outlet are arranged on the opposite side of each of the waste liquid chambers III. The different sides of I-2 are respectively provided with the electrode liquid outlet and the electrode liquid outlet;

The liquid outlet of the organic amine liquid storage device 1 is arranged in communication with the organic amine liquid inlet of the amine liquid chamber II of the membrane stack 4, and the liquid inlet of the organic amine liquid storage device 1 is connected to the membrane stack 4. The organic amine liquid outlet of the amine liquid chamber II is connected and arranged to form a closed loop and become an organic amine liquid circulation loop;

The electrode liquid outlet of the electrode liquid storage device 2 is arranged in communication with the electrode liquid inlet of the anode chamber 1-1 and the cathode chamber I-2, and the electrode liquid inlet of the electrode liquid storage device 2 is connected to the electrode liquid inlet of the electrode liquid storage device 2. The electrode liquid outlets of the anode chamber I-1 and the cathode chamber I-2 are communicated and arranged to form a closed loop and become an electrode liquid circulation loop;

The demineralized water outlet of the demineralized water storage device 3 is arranged in communication with the waste liquid inlet of the waste liquid chamber III, and the demineralized water liquid inlet of the demineralized water storage device 3 is connected to the waste liquid of the waste liquid chamber III. The outlet is connected and set up to form a closed loop and become a demineralized water circulation loop.

According to the present invention, in order to enable the membrane stack 4 to continue the process of electrodialysis even when the conductivity of the organic amine solution is reduced or even unable to conduct electricity, and to improve the desalination efficiency of the membrane stack 4 for thermally stable salts in the organic amine solution, preferably In this case, an ion exchange resin can also be filled between the two ion exchange membranes of each of the amine liquid chambers II separated in the membrane stack 4; the ion exchange resin can be a strongly acidic cation exchange resin and / or strongly basic anion exchange resin.

According to the present invention, the strong acid cation exchange resin can be a macroporous strong acid cation exchange resin and/or a gel type strong acid cation exchange resin, and the cation in the strong acid cation exchange resin can be any cation, Such as organic cations (such as quaternary ammonium cations), alkali metal ions (Na ⁺ , K ⁺ ), alkaline earth metal ions (such as Mg ²⁺ , Ca ²⁺ ), transition metal ions (such as Cu ²⁺ , Fe ³⁺ , Cr ^{3 ) +} , Zn ²⁺ , Co ²⁺ , Ni ²⁺ , etc.).

According to the present invention, the strong basic anion exchange resin can be a macroporous strong basic anion exchange resin and/or a gel strong basic anion exchange resin, and the anions in the strong basic anion exchange resin can be any An anion, such as SO ₄ ^2- , NO ₃ ^- , Cl ^- , HCO ₃ ^- , OH ^- etc.

According to the present invention, when there is no metal cation in the organic amine liquid treated by the system for removing thermally stable salts from the organic amine liquid, the ion exchange resin is preferably a strongly basic anion exchange resin, more preferably hydrogen Oxygen type strong basic anion exchange resin, because the organic amine solution is an alkaline solution, the most suitable for stabilizing ion conduction in alkaline solution is hydroxide type strongly basic anion exchange resin; When the system of heat-stable salt in amine solution contains metal cations in the organic amine solution, the ion exchange resin is preferably a mixture of strong basic anion exchange resin and strong acid cation exchange resin, more preferably hydroxide type strong cation exchange resin. The mixture of basic anion exchange resin and sodium type strong acid cation exchange resin, the volume ratio of the amount of the strong basic anion exchange resin and the strong acid cation exchange resin can be 0.5-2:1.

According to the present invention, the amount of the ion exchange resin is not particularly limited, as long as the conductivity of the organic amine solution is reduced or even can not conduct electricity. Preferably, the amount of the ion exchange resin is sufficient to fill the Each of the amine liquid chambers II.

According to the present invention, the electrode solution is an electrolyte solution, the concentration of the electrolyte solution can be 3-10% by weight, preferably 4-6% by weight, the solute of the electrolyte solution can be but not limited to sodium sulfate, chloride One or more of sodium, sodium nitrate, sodium acetate, potassium chloride, sodium hydroxide, sulfuric acid, hydrochloric acid, and nitric acid, the main purpose of which is to conduct electricity, ensure sufficient ions in and out, and improve current efficiency.

According to the present invention, the membrane stack 4 can be an cationic membrane stack or a bipolar membrane stack, and two adjacent ion exchange membranes with different permeabilities in the membrane stack 4 include a first ion exchange membrane A and a second ion exchange membrane A. Ion exchange membrane B, when the membrane stack 4 is an anion and cation membrane stack, the first ion exchange membrane A and the second ion exchange membrane B are each an anion exchange membrane or a cation exchange membrane; when the membrane stack 4 is a dual In the case of a polar membrane stack, the first ion exchange membrane A and the second ion exchange membrane B are each an anion exchange membrane or a bipolar membrane.

According to the present invention, when the membrane stack 4 is a cationic and cationic membrane stack, the membrane stack 4 may include multiple groups of ion exchange membranes, and each group of ion exchange membranes includes a cation exchange membrane and an anion exchange membrane to form a repeating unit , the repeating units formed by multiple groups of ion exchange membranes separate a plurality of periodically alternately arranged amine liquid chambers II and waste liquid chambers III. The arrangement of the ion-exchange membranes with different ion-selective permeability in the membrane stack 4 can be the conventional arrangement of anion and cation membrane stacks in the field. For example, the arrangement of the ion-exchange membranes in the membrane stack 4 can be As shown in FIG. 1 , in the membrane stack 4 , the first ion exchange membrane A is a cation exchange membrane, and the second ion exchange membrane B is an anion exchange membrane. To the direction of the cathode plate, the module sequentially includes a plurality of anion exchange membranes B and cation exchange membranes A that are periodically alternately arranged, and each anion exchange membrane B and cation exchange membrane A forms a repeating unit, and multiple groups of ion exchange membranes form a repeating unit. The repeating unit formed by the membrane separates a plurality of amine liquid chambers II and waste liquid chambers III which are arranged alternately periodically.

According to the present invention, when the membrane stack 4 is a bipolar membrane stack, the membrane stack 4 may include multiple groups of ion exchange membranes, each group of ion exchange membranes includes a bipolar membrane and an anion exchange membrane, forming a repeating Unit, the repeating unit formed by multiple groups of ion exchange membranes separates a plurality of periodically alternately arranged amine liquid chamber II and waste liquid chamber III. The arrangement of ion-exchange membranes with different ion-selective permeability in the membrane stack 4 can be the arrangement of conventional bipolar membrane stacks in the field, for example, the arrangement of the ion-exchange membranes in the membrane stack 4 As shown in FIG. 2, in the module stack 4, the first ion exchange membrane A is a bipolar membrane, the second ion exchange membrane B is an anion exchange membrane, and the membrane stack 4 further includes a third The ion exchange membrane C, the third ion exchange membrane C is a cation exchange membrane, is arranged close to the anode plate, in the die stack 4, from the third ion exchange membrane C to the cathode plate direction, the die The groups in turn include a plurality of anion exchange membranes B and bipolar membranes A that are arranged alternately in a periodic manner, each anion exchange membrane B and bipolar membrane A form a repeating unit, and the repeating units formed by the multiple groups of ion exchange membranes are separated into multiple groups. The amine liquid chamber II and the waste liquid chamber III are arranged alternately periodically.

According to the present invention, the bipolar membrane is an anionic and cationic composite ion-exchange membrane made of a cation-exchange membrane and an anion-exchange membrane. The characteristic of the bipolar membrane is that under the action of the DC electric field, the H ₂ O between the composite layers of the anion and cation exchange membranes dissociates into H ⁺ and OH ^- and passes through the anion membrane and the cation membrane, respectively, as H ⁺ and OH ^{- .} The ion source, its working principle is shown in Figure 2.

According to the present invention, when using the system for removing thermally stable salts from organic amine liquids provided by the present invention to treat organic amine liquids containing thermally stable salts that contain a large amount of strong cations, the membrane stack 4 can be a yin and yang membrane stack; When there are no metal cations in the organic amine solution containing thermally stable salts, the membrane stack 4 can be a cationic membrane stack or a bipolar membrane stack, preferably a bipolar membrane stack, when the membrane stack is an organic amine solution containing thermally stable salts. When there are no metal cations in the amine solution, and when the membrane stack 4 is a yin and yang membrane stack, the system further includes a lye input device, which inputs lye into the organic amine solution to be treated, and neutralizes the organic amine solution to be treated. The acidic substance is concentrated in the organic amine liquid to be treated to enrich strong cations, so as to avoid the removal of organic amine ions and the loss of organic amine liquid.

According to the present invention, the organic amine liquid circulation loop is also connected with an organic amine liquid output pipeline for outputting the organic amine liquid from which the thermally stable salt has been removed to the organic amine liquid reuse system, and the organic amine liquid output pipeline is A third regulating valve 63 is provided, and the demineralized water circulation loop is also connected with a waste liquid discharge line, which is used to discharge the demineralized water enriched with thermally stable salts as waste liquid to the outside of the system. A fourth regulating valve 64 is provided on the exhaust line, and the control center 5 is also used for receiving the conductivity signal from the first conductivity meter 91 and/or the second conductivity meter 92, and according to the first conductivity The conductivity signal of the conductivity meter 91 and/or the second conductivity meter 92 adjusts the opening of the third regulating valve 63 and/or the fourth regulating valve 64 . When the conductivity signals of the first conductivity meter 91 and/or the second conductivity meter 92 satisfy the organic amine liquid reuse standard and/or the waste liquid discharge standard, respectively, the control center 5 controls the third adjustment The opening timing and/or opening degree of the valve 63 and/or the fourth regulating valve 64 .

According to the present invention, the organic amine liquid circulation circuit is provided with a first circulation pump 71, the electrode liquid circulation circuit is provided with a second circulation pump 72, and the demineralized water circulation circuit is provided with a third circulation pump 73, respectively. It is used to circulate and pump the material in the organic amine liquid storage device 1 into the amine liquid chamber II of the membrane stack 4, and circulate the material in the electrode liquid storage device 2 into the anode chamber I-1 and the cathode chamber of the membrane stack 4. I-2, circulating and pumping the material in the demineralized water storage device 3 into the waste liquid chamber III of the membrane stack 4 . Preferably, the first circulating pump 71 , the second circulating pump 72 and the third circulating pump 73 are further provided with frequency converters for controlling the on-off and pump speed of each pump. More preferably, the starting speeds of the first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 are the same, and the first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 are The time of normal operation is 20-60s, more preferably 30-40s, the time from normal operation to complete stop of the first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 is 0-20s, more preferably for 5-10s. In addition, the frequency converter controls the operating frequency of the first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 to adjust the flow rate of each material entering the membrane stack 4 to ensure that the flow rate of each material is controllable .

Preferably, a filter is also provided on the connecting line from each circulating pump to the corresponding compartment of the membrane stack 4, and the number of the filters can be one or more to remove organic amine liquid, demineralized water and Solid particles in the electrode fluid.

According to the present invention, the solid particles in the organic amine solution, the demineralized water and the electrode solution are dust, fine particles, equipment corrosion shedding, degraded coke, reaction precipitates, etc. carried in the respective circulation processes. In order to remove the above-mentioned solid particulate matter, more preferably, the filter is a filter element type filter, the filter core is a pp cotton folded cotton core, and the filtration precision is 0.1-1 micron.

Further preferably, the outlet of the filter is also provided with a differential pressure gauge to monitor the retention state of the filter element gap of the filter.

Further preferably, a flow meter is also provided on the connecting pipeline from each circulating pump to the corresponding compartment of the membrane stack 4, and the flow meter may be one or more, and the flow meter is provided with a flow stop. detection device. The membrane stack 4 will generate heat during the energization process, and the generated heat is taken out of the membrane stack 4 with the circulation of each material and released. When the material is cut off, there is no material flow to cool down the membrane stack, and the membrane stack 4 The heat in the membrane stack will continue to accumulate, causing the material in the membrane stack 4 to gradually heat up or even boil, which is likely to cause the membrane stack 4 to overheat or even burn. When the material in a pipeline is cut off, the cut-off detection device can feed back the cut-off signal to the control center 5, and the control system cuts off the power supply of the membrane stack 4 to avoid the over-temperature phenomenon caused by the continuous power-on of the membrane stack 4.

According to the present invention, the organic amine liquid inlet, the waste liquid inlet and the electrode liquid inlet of the membrane stack 4 are respectively provided with a heat exchanger and a thermometer for regulating the temperature of the material entering the membrane stack 4 . Preferably, after heat exchange by the heat exchanger, the temperature of the material entering the membrane stack 4 is 5-35°C, preferably 15-25°C. If the temperature of the material flowing into the membrane stack 4 is too high, the effective ion exchange groups in the first ion exchange membrane A and the second ion exchange membrane B will be destroyed, and even the first ion exchange membrane A and the second ion exchange membrane will be destroyed. The structure of the exchange membrane B, if the temperature of the material flowing into the membrane stack 4 is too low, it may cause salt crystallization or water freezing in each material, which is easy to cause the first ion exchange membrane A and the second ion exchange membrane B. Deformation, or even destroying the structure of the first ion exchange membrane A and the second ion exchange membrane B, leads to the communication of liquids in different compartments, resulting in a decrease in the desalination capacity of the membrane stack 4 and loss of organic amine liquid.

According to the present invention, the system may also be provided with a lye liquid input device, and the conveying pipeline of the lye liquid input device is connected to the organic amine liquid storage device 1 . A seventh regulating valve 67 is provided on the conveying pipeline of the alkali solution input device, which is used to adjust the input timing and flow rate of the alkali solution in the alkali solution input device according to the type of organic amine solution actually processed. According to the present invention, the lye can be but not limited to sodium hydroxide and/or potassium hydroxide. When the organic amine liquid to be treated lacks cations, it can be supplemented as needed after supplementing the organic amine liquid according to the actual situation. lye to avoid the loss of organic amine solution in the desalination process.

According to the present invention, the system is further provided with an inert gas access device, and the transmission pipelines of the inert gas access device are respectively connected to the organic amine liquid storage device 1 , the electrode liquid storage device 2 and the demineralized water storage device 3 . The storage devices in each circulation loop are sealed with inert gas to ensure that the amine liquid and the like are isolated from the air in their respective circulation tanks and will not be oxidized. Preferably, the inert gas is nitrogen.

According to the present invention, the membrane stack 4 is further provided with a cleaning device. When the electrodialysis efficiency of the first ion exchange membrane A and/or the second ion exchange membrane B in the membrane stack 4 decreases or is polluted, the The first ion exchange membrane A and/or the second ion exchange membrane B are cleaned to maintain the high desalination efficiency of the membrane stack 4 .

Preferably, the organic amine liquid storage device 1 is also provided with an organic amine liquid level meter 81, and the demineralized water storage device 2 is also provided with a demineralized water level meter 82, which are respectively used to detect the organic amine liquid The liquid level in the storage device 1 and the demineralized water storage device 2, and then the liquid level signal of the two is sent to the control center 5, and the control center 5 is based on the organic amine liquid level meter 81 and/or The liquid level signal of the demineralized water level meter 82 adjusts the opening and switching timing of the fifth regulating valve 65 on the amine liquid input line and/or the sixth regulating valve 66 on the demineralized water input line, thereby controlling The rehydration dosage and flow rate of the organic amine liquid storage device 1 and the demineralized water storage device 2; the control center 5 can also The position signal further controls the opening degree and switching timing of the third regulating valve 63 and/or the fourth regulating valve 64, and cooperatively controls the circulation of the organic amine liquid in the organic amine liquid circulation loop and/or the waste liquid in the demineralized water circulation loop Start or stop and recycle flow.

According to the present invention, in order to facilitate installation and simplify operation, the system is preferably a skid-mounted system.

The second aspect of the present invention provides a method for treating an organic amine solution containing a heat-stable salt by using the aforementioned system for removing heat-stable salts from an organic amine solution, the method comprising introducing the organic amine solution to be treated into the The organic amine solution storage device 1 of the system introduces demineralized water into the demineralized water storage device 3 of the system, and the electrode solution is passed into the electrode solution storage device 2, and then the organic amine solution is circulated and pumped into the membrane In the amine liquid chamber II of the stack 4, the demineralized water in the demineralized water storage device 3 is circulated and pumped into the waste liquid chamber III of the membrane stack 4, and the electrode solution in the electrode solution storage device 2 is circulated and pumped into the The anode chamber I-1 and the cathode chamber I-2 of the membrane stack 4; the anode plate and the cathode plate of the membrane stack 4 are respectively connected with the positive electrode and the negative electrode of the power supply, so that the organic material to be treated is pumped into the membrane stack 4 for circulation. The amine solution is subjected to heat-stable salt removal treatment to obtain an organic amine solution from which heat-stable salts are removed and demineralized water enriched with heat-stable salts. When the brine meets the recovery and discharge standards respectively, the organic amine solution obtained after the treatment with the heat-stable salt removed is transported to the organic amine solution reuse system, and the demineralized water enriched with the heat-stable salt obtained after the treatment is discharged as a waste liquid to all facilities. outside the system.

According to the present invention, preferably, the power supply connected to the anode plate and the cathode plate of the membrane stack 4 is an explosion-proof DC power supply.

According to the present invention, the current density generated after the anode plate and the cathode plate are connected to a power source can be selected and set according to the thermally stable salt concentration in the organic amine solution to be treated and/or the electrical conductivity of the organic amine solution, for example, When the thermally stable salt concentration in the organic amine solution to be treated is 0.5-10% by weight, or when the conductivity of the organic amine solution to be treated is 1-20 ms, the current density may be 5-400 mA/cm ² . The voltage and current of the power supply can be set according to the membrane area in the membrane stack 4, as long as the current density is controlled within the range of 5-400 mA/cm ² . The number of ion exchange membranes in the membrane stack 4 can be 20-200 groups, and each group of ion exchange membranes includes two ion exchange membranes with different ion selective permeability to form a repeating unit. For example, when the membrane stack 4 is yin and yang When the membrane stack is used, a set of ion exchange membranes includes a cation exchange membrane and an anion exchange membrane, and when the membrane stack 4 is a bipolar membrane stack, a set of ion exchange membranes includes an anion exchange membrane and a bipolar membrane. When the membrane stacks 4 are cationic and cationic membrane stacks or bipolar membrane stacks respectively, the working principle of the membrane stacks 4 and the arrangement of ion exchange membranes with different ion selective permeability are as described above, and will not be repeated here. . The size of the ion exchange membrane in the membrane stack 4 conforms to the relevant national and industry standards. The ion exchange membrane of 400mm×800mm is commonly used in the industry to assemble the membrane stack, and the ion exchange membrane of 200mm×400mm is also used to assemble the membrane stack. The present invention is not limited to the above Two sizes of membrane stacks.

According to the present invention, when the organic amine solution to be treated passes through the membrane stack 4 in which the anode plate and the cathode plate are respectively connected to the positive electrode and the negative electrode of the power supply, the charged particles in the heat-stable salt in the organic amine solution are subjected to an external direct current electric field. Driven by the difference in ion-selective permeability of the first ion exchange membrane A and the second ion exchange membrane B, that is, cations can pass through the cation exchange membrane, and anions can pass through the anion exchange membrane. The charged organic amine liquid molecules cannot move through the anion and cation exchange membrane, but stay in the corresponding amine liquid chamber II. During the circulation flow of the organic amine liquid, the thermally stable salt is continuously removed, and the charged The ions move to the corresponding waste liquid chamber III, and are removed from the organic amine liquid during the circulation flow of the desalinated water, so as to achieve the purposes of desalination, concentration, purification or purification of the organic amine liquid. In addition, the H ₂ O between the composite layers of the anion and cation exchange membranes in the bipolar membrane dissociates into H ⁺ and OH ^- and passes through the anion and cation membranes, respectively, as the source of H ⁺ and OH ^- ions, when the organic amine to be treated When the heat-stable salt contained in the liquid has no metal cations, the bipolar membrane can be used to generate H ⁺ and the heat-stable salt anion removed from the organic amine liquid can be combined to form an acid, which is enriched in the demineralized water to form a waste liquid and discharged. out of the system.

The organic amine solution of the present invention exists in the form of molecules in the aqueous solution, and itself does not carry electrons, and its electrical conductivity depends entirely on the thermally stable salt therein. However, with the progress of the purification process, the thermally stable organic amine solution As the salt concentration continues to decrease, the conductivity of the organic amine solution will gradually decrease. In theory, when the thermally stable salt concentration decreases to 0 or close to 0, there are almost no movable charged particles in the organic amine solution, which causes the conductivity of the organic amine solution. reduce or even fail to conduct electricity. At this time, if the membrane stack 4 is still energized, the current cannot pass through or the energization is blocked due to the decrease in the conductivity of the organic amine solution in the amine solution chamber II, which will cause serious consequences, such as: (1) organic amine The ionization of the liquid into the waste liquid chamber III causes the loss of the organic amine liquid, and further desalination cannot be completed; (2) the current efficiency will be reduced, and the electrical energy will be further converted into heat energy, resulting in an increase in the temperature of the organic amine liquid, which is irreversible to the ion exchange membrane. damage. The above problems can be avoided by setting the discharge conductivity of the organic amine liquid, that is, when the conductivity of the organic amine liquid is not reduced to 0 or close to 0, it is discharged into the organic amine liquid recycling system. However, the heat in the organic amine liquid The continuous removal of the stable salt by the method of the present invention always makes the thermally stable salt reach a very low level. At this time, once the thermally stable salt is removed, the above consequences will occur, and the removal of the thermally stable salt can only be stopped. That is to say, the concentration of thermally stable salt cannot be reduced to a level close to 0 or to 0. In order to solve this problem, preferably, ion exchange resin is filled in the amine liquid chamber II of electrodialysis, and the conductivity of the organic amine liquid decreases. Even when it is not conductive, the ion exchange resin acts as a conductive medium, which can effectively promote the electrodialysis process and improve the electrodialysis desalination efficiency and desalination depth.

According to the present invention, the selection and dosage of the ion exchange resin are as described above, and will not be repeated here.

According to the present invention, the organic amine liquid to be treated can be monoethanolamine containing thermally stable salt, diethanolamine containing thermally stable salt, N-methyldiethanolamine containing thermally stable salt, triethanolamine containing thermally stable salt, containing N-methylethylenediamine with heat stable salt, diisopropanolamine with heat stable salt, N,N-dibutylethanolamine with heat stable salt, ethylenediamine with heat stable salt, with heat stable salt At least one of diethylamine containing thermally stable salts, tetramethylethylenediamine containing thermally stable salts, and piperazine containing thermally stable salts.

For example, MDEA is commonly used as a desulfurizer in the desulfurization of liquefied gas in refineries. The desulfurizer will be partially degraded and oxidized to generate formate and acetate during the recycling process, and the sulfide generated by desulfurization will also be oxidized to sulfate, sulfite, thiol Sulfate, etc., these anions can exist stably at the regeneration temperature of the desulfurizer, which is the so-called heat stable salt (HSS). It further promotes the deterioration and degradation of the amine solution, forming a vicious circle, which ultimately affects the desulfurization depth and desulfurization efficiency of the amine solution. What's more, some refineries will introduce strong cations (such as Na ⁺ , K ⁺ , Ca ²⁺ , Mg ²⁺ , etc.) into the amine solution for one reason or another, and the strong cations will form thermal stability during the desulfurization process. sulfides, resulting in an increase in the content of hydrogen sulfide in the lean amine liquid, affecting the desulfurization depth and desulfurization efficiency, resulting in unqualified desulfurization.

The method for treating the organic amine liquid containing the thermally stable salt by using the system for removing thermally stable salts in the organic amine liquid of the present invention can simultaneously remove strong cations and thermally stable salt anions in the organic amine liquid to be treated (for example, sodium ions Simultaneous removal with acetate ions will form sodium acetate), which will accumulate to a certain concentration in demineralized water and be discharged.

According to the present invention, the organic amine solution, demineralized water and electrode solution undergo heat exchange before entering the membrane stack 4, and the temperature of the organic amine solution, demineralized water and electrode solution after heat exchange is 5-35°C, It is preferably 15-25°C.

According to the present invention, the organic amine solution, demineralized water and electrode solution are filtered before entering the membrane stack 4 to remove solid particles with a particle size of 0.1-1 micron in the organic amine solution, demineralized water and electrode solution.

According to the present invention, preferably, during the treatment of the organic amine solution, the flow rates of the organic amine solution and the demineralized water may be 1-10 m ³ /h, preferably 2-5 m ³ /h, and the The flow rate of the electrode solution can be 1-5 m ³ /h, preferably 2-4 m ³ /h. Before entering the membrane stack 4, the organic amine solution, the demineralized water and the electrode solution are divided into a plurality of tributaries, each of which enters the corresponding compartment in the membrane stack 4, and the flow rate of each tributary remains unchanged, or is evenly distributed to the same. flow.

The present invention will be described in detail below by means of examples.

Example 1

The system for removing thermally stable salts from an organic amine solution provided in this embodiment is a skid-mounted system, the schematic diagram of which is shown in Figure 1, and the system includes: an organic amine solution storage device 1, an electrode solution storage device 2, and a demineralized water storage device The device 3, the membrane stack 4 and the control center 5, wherein the membrane stack 4 is respectively connected to the organic amine solution storage device 1, the electrode solution storage device 2 and the demineralized water storage device 3; the membrane stack 4 At least one organic amine liquid inlet, organic amine liquid outlet, waste liquid inlet, waste liquid outlet, electrode liquid inlet and electrode liquid outlet are provided; the organic amine liquid outlet and the waste liquid outlet are respectively provided with a first conductivity The conductivity meter 91 and the second conductivity meter 92 are used to monitor the liquid conductivity at the outlet of the organic amine liquid and the outlet of the waste liquid; A first regulating valve 61 is provided on the material conveying pipeline between the two sides, and a second regulating valve 62 is arranged on the material conveying pipeline between the demineralized water storage device 3 and the waste liquid inlet; the system also includes a control center 5, for receiving the conductivity signal from the first conductivity meter 91 and/or the second conductivity meter 92, and according to the conductivity of the first conductivity meter 91 and/or the second conductivity meter 92 The signal adjusts the opening of the first regulating valve 61 and/or the second regulating valve 62 .

The membrane stack 4 includes an anode plate and a cathode plate oppositely arranged at both ends of the membrane stack 4, and a module containing a plurality of ion exchange membranes arranged between the anode plate and the cathode plate; The area between the groups forms the anode chamber I-1, and the area between the cathode plate and the module forms the cathode chamber I-2; the plurality of ion exchange membranes are separated into a plurality of cycles within the module The amine liquid chamber II and the waste liquid chamber III are alternately arranged; the ion selective permeability of the two adjacent ion exchange membranes is different; the organic amine liquid inlet is arranged on the opposite side of each amine liquid chamber II and the organic amine liquid outlet, the waste liquid inlet and the waste liquid outlet are set on the different sides of each of the waste liquid chambers III, and the anode chamber I-1 and the cathode chamber I-2 are respectively set on the different sides of the Electrode liquid outlet and electrode liquid outlet; the liquid outlet of the organic amine liquid storage device 1 is arranged in communication with the organic amine liquid inlet of the amine liquid chamber II of the membrane stack 4, and the organic amine liquid storage device 1 The liquid inlet is communicated with the organic amine liquid outlet of the amine liquid chamber II of the membrane stack 4 to form a closed loop and become an organic amine liquid circulation loop; the electrode liquid liquid outlet of the electrode liquid storage device 2 is connected to the anode. The electrode solution inlet of chamber 1-1 and cathode chamber I-2 is communicated and set, and the electrode solution inlet of described electrode solution storage device 2 is communicated with the electrode solution outlet of described anode chamber 1-1 and cathode chamber 1-2. , form a closed loop and become an electrode liquid circulation loop; the demineralized water outlet of the demineralized water storage device 3 is set in communication with the waste liquid inlet of the waste liquid chamber III, and the demineralized water of the demineralized water storage device 3 enters the liquid. The port is arranged in communication with the waste liquid outlet of the waste liquid chamber III to form a closed loop and become a demineralized water circulation loop.

The organic amine liquid circulation loop is also connected with an organic amine liquid output pipeline, which is used for outputting the organic amine liquid from which the thermally stable salt is removed to the organic amine liquid recycling system for removing the thermally stable salt. The amine liquid output pipeline A third regulating valve 63 is provided thereon, the demineralized water storage device 3 is also connected with a waste liquid discharge line for discharging the waste liquid to the outside of the system, and a fourth waste liquid discharge line is provided on the The regulating valve 64, the control center 5 is also used to receive the conductivity signals from the first conductivity meter 91 and the second conductivity meter 92, and according to the first conductivity meter 91 and the second conductivity meter The conductivity signal of 92 adjusts the opening degrees of the third regulating valve 63 and the fourth regulating valve 64 .

The organic amine liquid circulation circuit is provided with a first circulation pump 71, the electrode liquid circulation circuit is provided with a second circulation pump 72, and the demineralized water circulation circuit is provided with a third circulation pump 73, which are respectively used for The material in the described organic amine liquid storage device 1 is circulated and pumped into the amine liquid chamber II of the membrane stack 4, and the material in the electrode liquid storage device 2 is circulated and pumped into the anode chamber I-1 and the cathode chamber I-2 of the membrane stack 4, The material in the demineralized water storage device 3 is circulated and pumped into the waste liquid chamber III of the membrane stack 4 . The first circulating pump 71 , the second circulating pump 72 and the third circulating pump 73 are also provided with frequency converters for controlling the on-off and pump speed of each pump. The starting speed of the first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 is the same, and the time from starting to normal operation is 35s. The first circulating pump 71, the second circulating pump 72 and the The time from the normal operation to the complete stop of the third circulating pump 73 is the same, which is 5s.

A filter is also provided on the connecting line from each circulating pump to the corresponding compartment of the membrane stack 4 . The filter is a filter element, and the filter core is a pp cotton folded cotton core with a filtration accuracy of 0.1 micron.

The outlet of the filter is also provided with a differential pressure gauge to monitor the retention state of the filter element gap of the filter.

A flow meter is also provided on the connecting pipeline from each circulating pump to the corresponding compartment of the membrane stack 4 , and a flow interruption detection device is provided on the flow meter.

The organic amine liquid inlet, waste liquid inlet and electrode liquid inlet of the membrane stack 4 are respectively provided with a heat exchanger and a thermometer to adjust the temperature of the material entering the membrane stack 4 to 20°C.

The system is also provided with a nitrogen generating device, and the conveying pipelines of the nitrogen generating device are respectively connected to the organic amine liquid storage device 1, the electrode liquid storage device 2 and the demineralized water storage device 3, and the storage devices in each circulation loop are respectively connected to the storage device 1. Nitrogen sealing ensures that the amine liquid, etc., is isolated from the air in their respective circulation tanks and will not be oxidized.

The membrane stack 4 is also provided with a cleaning device for cleaning the first ion exchange membrane A and/or the second ion exchange membrane B.

The organic amine liquid storage device 1 is also provided with an organic amine liquid level meter 81, and the demineralized water storage device 2 is also provided with a demineralized water level meter 82, which are respectively used to detect the organic amine liquid storage device 1. and the liquid level in the demineralized water storage device 2, and then send the liquid level signals of the two to the control center 5, and the control center 5 is based on the organic amine liquid level meter 81 and/or the demineralized liquid. The liquid level signal of the level meter 82 adjusts the opening of the fifth regulating valve 65 on the amine liquid input line and/or the sixth regulating valve 66 on the demineralized water input line, and then controls the storage of the organic amine liquid The amount and flow rate of the rehydration of the device 1 and/or the demineralized water storage device 2; the control center 5 can also further according to the liquid level signal of the organic amine liquid level instrument 81 and/or the demineralized water liquid level instrument 82. Control the opening degree and switching timing of the third regulating valve 63 and/or the fourth regulating valve 64, and coordinately control the cycle start or stop of the organic amine liquid in the organic amine liquid circulation loop and/or the waste liquid in the demineralized water circulation loop and circulating flow.

When using the aforementioned system for removing thermally stable salts from organic amine liquids to process organic amine liquids containing thermally stable salts, the organic amine liquid to be treated is introduced into the organic amine liquid storage device 1 of the system through an external pipeline, and the demineralized water is introduced into the organic amine liquid storage device 1 of the system. To the demineralized water storage device 3 of the system, the electrode solution is passed into the electrode solution storage device 2, and then the organic amine solution is circulated and pumped into the amine solution chamber II of the membrane stack 4, and the demineralized water is The demineralized water in the storage device 3 is circulated and pumped into the waste liquid chamber III of the membrane stack 4, and the electrode solution in the electrode solution storage device 2 is circulated and pumped into the anode chamber 1-1 and the cathode chamber 1 of the membrane stack 4 respectively. -2; the anode plate and the cathode plate of the membrane stack 4 are respectively connected with the positive pole and the negative pole of the explosion-proof direct current power supply, so that the organic amine solution to be treated which is pumped into the membrane stack 4 is circulated to carry out the heat-stabilizing salt removal treatment, Obtain the organic amine solution from which heat-stable salt is removed and the desalinated water enriched with heat-stable salt, and when the obtained organic amine solution from which heat-stable salt is removed and the demineralized water from which heat-stable salt is enriched meet the recycling and discharge standards, respectively, will be treated. The obtained organic amine liquid from which the thermally stable salt has been removed is transported to the organic amine liquid reuse system, and the thermally stable salt-enriched demineralized water obtained after the treatment is discharged to the outside of the system as a waste liquid.

In this embodiment, the organic amine solution to be treated is taken from Dalian West Pacific Petrochemical Co., Ltd., and its composition is shown in Table 1. The membrane stack 4 is a yin and yang membrane stack, and its structural schematic diagram and working principle are shown in Figure 1 , the first ion exchange membrane A is a cation exchange membrane, the second ion exchange membrane B is an anion exchange membrane, and the anion and cation membrane stacks include 100 groups of cation exchange membranes and anion exchange membranes that are periodically alternately arranged, From the anode plate to the cathode plate, the module sequentially includes a plurality of anion-exchange membranes B and cation-exchange membranes A that are periodically alternately arranged, and each anion-exchange membrane B and cation-exchange membrane A The repeating unit formed by the group of ion exchange membranes separates a plurality of periodically alternately arranged amine liquid chambers II and waste liquid chambers III. Demineralized water is deionized water, and the electrode solution is a sodium sulfate solution with a concentration of 6% by weight. The first circulating pump 71, the second circulating pump 72 and the third circulating pump 73 are provided with a frequency converter, and the frequency converter setting frequency is 29Hz, and the circulating flow of the control organic amine liquid and the demineralized water is 4m ³ /h, and the electrode The pumping flow rate of the liquid is 2m ³ /h, the flow rate of the tributaries flowing into the anode chamber I-1 and the cathode chamber I-2 is 1m ³ /h, the voltage of the explosion-proof DC power supply is 130V, the current is 110A, and the current density is 150mA/cm ² , the control center 5 sets the conductivity signal difference value of the organic amine liquid to 10ms, and the conductivity signal value of the demineralized water discharged as waste liquid is 55ms, when the first conductivity meter 91 When the measured conductivity signal difference is 10ms, the control center 5 regulates and controls the first regulating valve 61 to close, and opens the third regulating valve 63 set on the output pipeline of the organic amine liquid, and the processed The organic amine liquid is output to the organic amine liquid reuse system, when the amine liquid conductivity signal value measured by the second conductivity meter 92 is 55ms, the control center 5 regulates and regulates the second regulating valve 62 to close, and The fourth regulating valve 64 provided on the waste liquid discharge line is opened, and the demineralized water enriched with thermally stable salt is discharged from the system as waste liquid.

Take the treated organic amine solution and demineralized water for detection, and the detection results are shown in Table 1.

Table 1

sample Organic Amine Liquid Concentration Conductivity Na⁺Concentration Cl^-Concentration Heat stable salt concentration To-be-treated organic amine solution 25.5 wt% 14ms 8300mg/L 15240mg/L 6.69% by weight Organic amine solution after treatment 26.19% by weight 4ms 600mg/L 1160mg/L 0.75% by weight Demineralized water - 55ms 16600mg/L 31640mg/L 12.87% by weight

As can be seen from Table 1, the conductivity of the organic amine solution decreased after the treatment, and the concentrations of sodium ions, chloride ions and thermally stable salts decreased, while the conductivity of the demineralized water increased from 0 (deionized water) to 55ms, and the thermal stability decreased. The salt concentration reaches 12.87% by weight, indicating that the thermally stable salt in the organic amine solution to be treated enters the desalinated water under the action of the DC electric field, and the desalted water enriched with the thermally stable salt is discharged as a waste liquid, which achieves the high thermal stability in the organic amine solution. The purpose of stable salt removal.

Example 2

The system for removing thermally stable salts in organic amine liquid provided in this embodiment and the method for using the system for removing thermally stable salts in organic amine liquids to treat organic amine liquid containing thermally stable salts are as in Example 1, except that , the membrane stack 4 is a bipolar membrane stack, and its schematic structural diagram and working principle are shown in Figure 2, the first ion exchange membrane A is a bipolar membrane, the second ion exchange membrane B is an anion exchange membrane, The bipolar membrane stack includes 100 groups of bipolar membranes and anion exchange membranes and a third ion exchange membrane C, which are periodically alternately arranged, and the third ion exchange membrane C is a cation exchange membrane, which is arranged close to the Anode plate, from the third ion exchange membrane C to the cathode plate direction, the module sequentially includes a plurality of anion exchange membranes B and bipolar membranes A which are periodically alternately arranged, each anion exchange membrane B and bipolar membrane A forms a repeating unit, and the repeating units formed by multiple groups of ion exchange membranes separate a plurality of periodically alternately arranged amine liquid chambers II and waste liquid chambers III. The control center 5 sets the conductivity signal difference value of the organic amine liquid to 15ms, and the conductivity signal value of the demineralized water discharged as waste liquid is 55ms. When the conductivity signal measured by the first conductivity meter 91 When the difference is 15ms, the control center 5 regulates and controls the first regulating valve 61 to close, and opens the third regulating valve 63 set on the output pipeline of the organic amine liquid, and the processed organic amine liquid that reaches the standard is output to the organic amine liquid. In the amine liquid reuse system, when the amine liquid conductivity signal value measured by the second conductivity meter 92 is 55ms, the control center 5 regulates and controls the second regulating valve 62 to close, and opens the waste liquid discharge pipeline The fourth regulating valve 64 provided above discharges the demineralized water enriched with thermally stable salts out of the system as waste liquid.

The organic amine liquid to be treated is industrial pure MDEA self-preparation (add hydrochloric acid in the amine liquid) organic amine liquid, and its composition is as shown in Table 2, get the organic amine liquid and demineralized water after processing and detect, and the detection result is as shown in Table 2. Show.

Table 2

sample Organic Amine Liquid Concentration Conductivity Metal cation concentration Cl^-Concentration To-be-treated organic amine solution 25% by weight 18.8ms 0mg/L 20000mg/L Organic amine solution after treatment 25% by weight 3.8ms 0mg/L 800mg/L Demineralized water - 55ms 0mg/L 35870mg/L

As can be seen from Table 2, the conductivity of the organic amine solution decreased after the treatment, and the chloride ion concentration decreased, while the conductivity of the demineralized water increased from 0 (deionized water) to 55ms, and the main component in the demineralized water was hydrochloric acid. The chloride ion content is 35870mg/L, indicating that under the action of the bipolar membrane, the chloride ions in the organic amine solution to be treated and the H ⁺ generated by the bipolar membrane combine into the demineralized water storage device to form hydrochloric acid, while the bipolar membrane produces hydrochloric acid. OH ^- enters into the organic amine liquid circulation loop to neutralize the hydrochloric acid added in the organic amine liquid to be treated, so as to achieve the purpose of removing thermally stable salts in the organic amine liquid to be treated.

Example 3

The system for removing thermally stable salts in organic amine liquid provided in this embodiment and the method for using the system for removing thermally stable salts in organic amine liquids to treat organic amine liquid containing thermally stable salts are as in Example 1, except that , the system is also provided with a lye liquid input device, the liquid outlet of the lye liquid input device is communicated with the organic amine liquid inlet of the membrane stack 4 . The alkali solution is sodium hydroxide, and the concentration of the alkali solution is 30% by weight.

The organic amine liquid to be treated is industrial pure MDEA self-preparation (add hydrochloric acid in the amine liquid) organic amine liquid, and its composition is as shown in Table 3, get the organic amine liquid after processing and demineralized water and detect, the detection result is as shown in Table 3. Show.

table 3

As can be seen from Table 3, the conductivity of the organic amine solution decreased after treatment, the concentrations of sodium ions, chloride ions and thermally stable salts decreased, while the conductivity of demineralized water increased from 0 (deionized water) to 55ms, indicating that when When there are no metal cations in the organic amine liquid to be treated, the method of adding alkali solution can be used to remove the heat-stable salt from the organic amine liquid to be treated by an anion-yang membrane stack, so as to achieve the compatibility with the organic amine liquid containing metal cations. The same desalination effect is obtained, and the organic amine solution after treatment will not cause the loss of the organic amine solution.

Example 4

The system for removing heat-stable salts in organic amine solution provided in this embodiment and the method for treating organic amine solution containing heat-stable salts by using the system for removing heat-stable salts in organic amine solution are as in Example 1, the difference is In the anion-yang membrane stack used, the amine liquid chamber II is filled with a mixture of hydroxide type strong base anion exchange resin and sodium type cation exchange resin with a volume ratio of 1:1.

The control center 5 sets the conductivity signal value of the organic amine liquid discharge to 0ms, and the conductivity signal value of the demineralized water discharged as waste liquid is 55ms. When the first conductivity meter 91 measures the conductivity of the amine liquid. When the rate signal value is 0ms, the control center 5 regulates and controls the first regulating valve 61 to close, and opens the third regulating valve 63 set on the output pipeline of the organic amine liquid, and the processed organic amine liquid that reaches the standard is output to In the organic amine liquid reuse system, when the amine liquid conductivity signal value measured by the second conductivity meter 92 is 55ms, the control center 5 regulates and controls the second regulating valve 62 to close, and opens the waste liquid discharge The fourth regulating valve 64 set on the pipeline discharges the demineralized water enriched with thermally stable salt out of the system as waste liquid.

Take the treated organic amine liquid and waste liquid for detection, and the detection results are shown in Table 4.

Table 4

sample Organic Amine Liquid Concentration Conductivity Na⁺Concentration Cl^-Concentration Heat stable salt concentration To-be-treated organic amine solution 25.5 wt% 14ms 8300mg/L 15240mg/L 6.69% by weight Organic amine solution after treatment 26.3 wt% 0ms <10mg/L <10mg/L 0 wt% Demineralized water - 55ms 16880mg/L 32100mg/L 13.1 wt%

It can be seen from Table 4 that under the action of ion exchange resin as a conductive medium, the depth of electrodialysis desalination increases. Under the same treatment conditions, the concentrations of sodium ions, chloride ions and thermally stable salts in the organic amine solution after treatment drop to close to 0, while the demineralized water increases from 0 (deionized water) conductivity to 55ms, and the thermally stable salt concentration reaches 13.1% by weight, indicating that almost all the thermally stable salts in the organic amine solution to be treated enter the deionized water under the action of the DC electric field. In the brine, the demineralized water enriched with thermally stable salts is discharged as waste liquid to achieve the purpose of deep removal of thermally stable salts in the organic amine solution.

Example 5

The system for removing heat-stable salts in organic amine solution provided by this embodiment and the method for treating organic amine solution containing heat-stable salts by using the system for removing heat-stable salts in organic amine solution are as in Example 2, the difference is In the bipolar membrane stack used, the amine liquid chamber II is filled with hydroxide type strong basic anion exchange resin.

The control center 5 sets the conductivity signal value of the organic amine liquid discharge to 0ms, and the conductivity signal value of the demineralized water discharged as waste liquid is 55ms. When the first conductivity meter 91 measures the conductivity of the amine liquid. When the rate signal value is 0ms, the control center 5 regulates and controls the first regulating valve 61 to close, and opens the third regulating valve 63 set on the output pipeline of the organic amine liquid, and the processed organic amine liquid that reaches the standard is output to In the organic amine liquid reuse system, when the amine liquid conductivity signal value measured by the second conductivity meter 92 is 55ms, the control center 5 regulates and controls the second regulating valve 62 to close, and opens the waste liquid discharge The fourth regulating valve 64 set on the pipeline discharges the demineralized water enriched with thermally stable salt out of the system as waste liquid.

Take the treated organic amine solution and demineralized water for detection, and the detection results are shown in Table 5.

table 5

sample Organic Amine Liquid Concentration Conductivity Metal cation concentration Cl^-Concentration To-be-treated organic amine solution 25% by weight 18.8ms 0mg/L 20000mg/L Organic amine solution after treatment 25% by weight 0ms 0mg/L <10mg/L Demineralized water - 55ms 0mg/L 35590mg/L

It can be seen from Table 5 that under the action of ion exchange resin as a conductive medium, the depth of electrodialysis desalination increases. Under the same treatment conditions, the chloride ion concentration in the organic amine solution after treatment drops to close to 0, while the demineralized water is reduced by the conductivity The rate rises from 0 (deionized water) to 55ms, indicating that almost all the thermally stable salts in the organic amine solution to be treated enter the desalinated water under the action of the DC electric field, and the desalted water enriched with thermally stable salts is discharged as waste liquid , to achieve the purpose of deep removal of thermally stable salts in organic amine liquid.

It can be seen from the results in Tables 1-5 that the system for removing thermally stable salts from organic amine liquids provided by the present invention is suitable for processing organic amine liquids containing different thermally stable salts, with a high degree of automation, strong desalination capability, and no manual intervention in the whole process. , saving labor costs. Using the system to treat organic amine liquid containing thermally stable salts can not only realize the simultaneous removal of anions and cations in the amine liquid, but also effectively remove solid particles in the organic amine liquid, greatly reducing the consumption of lye and waste liquid. Low emissions enhance the repeatable service life of organic amine fluids.

The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims (12)

1. A system for removing thermally stable salts in an organic amine solution, the system comprising: an organic amine solution storage device (1), an electrode solution storage device (2), a demineralized water storage device (3), a membrane stack (4) and a control center (5), characterized in that the membrane stack (4) is respectively connected to the organic amine solution storage device (1), the electrode solution storage device (2) and the demineralized water storage device (3) ; The membrane stack (4) is provided with at least one organic amine liquid inlet, organic amine liquid outlet, waste liquid inlet, waste liquid outlet, electrode liquid inlet and electrode liquid outlet; the organic amine liquid outlet and the waste liquid The outlet is provided with a first conductivity meter (91) and a second conductivity meter (92), respectively, for monitoring the liquid conductivity at the outlet of the organic amine liquid and the outlet of the waste liquid; the organic amine liquid A first regulating valve (61) is provided on the material conveying pipeline between the outlet and the organic amine liquid storage device (1), and the material between the demineralized water storage device (3) and the waste liquid inlet is provided with a first regulating valve (61). A second regulating valve (62) is provided on the delivery line; the control center (5) is used to receive the conductivity signal from the first conductivity meter (91) and/or the second conductivity meter (92), And according to the conductivity signal of the first conductivity meter (91) and/or the second conductivity meter (92), the adjustment of the first regulating valve (61) and/or the second regulating valve (62) opening. 2. The system according to claim 1, wherein the membrane stack (4) comprises an anode plate, a cathode plate arranged oppositely at both ends of the membrane stack (4), and a cathode plate arranged between the anode plate and the cathode plate. A plurality of ion exchange membrane modules; the region between the anode plate and the module forms an anode chamber (I-1), and the region between the cathode plate and the module forms a cathode chamber (I-1) 2); the plurality of ion exchange membranes are separated into a plurality of periodically alternately arranged amine liquid chambers (II) and waste liquid chambers (III) in the module; the ions of two adjacent ion exchange membranes The selective permeability is different; the organic amine liquid inlet and the organic amine liquid outlet are arranged on the opposite side of each of the amine liquid chambers (II), and the organic amine liquid inlet and the organic amine liquid outlet are arranged on the opposite side of each of the waste liquid chambers (III). A waste liquid inlet and a waste liquid outlet, the electrode liquid outlet and the electrode liquid outlet are respectively provided on the opposite sides of the anode chamber (I-1) and the cathode chamber (I-2); The organic amine liquid storage device (1) is provided with a liquid inlet and a liquid outlet, the liquid outlet is communicated with the organic amine liquid inlet, and the liquid inlet is communicated with the organic amine liquid outlet to form an organic amine liquid. Amine liquid circulation loop; The electrode liquid storage device (2) is provided with an electrode liquid liquid inlet and an electrode liquid liquid outlet, the electrode liquid liquid outlet is communicated with the electrode liquid inlet, and the electrode liquid liquid inlet is connected with the electrode liquid liquid inlet. The outlet is connected to form an electrode liquid circulation loop; The desalinated water storage device (3) is provided with a desalted water inlet and a desalted water outlet, the desalted water outlet is communicated with the waste liquid inlet, and the desalted water inlet is connected with the waste liquid The outlet is communicated to form a demineralized water circulation loop. 3. The system according to claim 2, wherein an ion exchange resin is also filled between the two ion exchange membranes of each of the amine liquid chambers (II) separated in the membrane stack (4); The ion exchange resin is a strongly acidic cation exchange resin and/or a strongly basic anion exchange resin. 4. The system according to claim 2, wherein the membrane stack (4) is a cathodic membrane stack or a bipolar membrane stack, and two adjacent ions in the membrane stack (4) with different permeabilities are selected The exchange membrane includes a first ion exchange membrane (A) and a second ion exchange membrane (B); When the membrane stack (4) is an anion and cation membrane stack, the first ion exchange membrane (A) and the second ion exchange membrane (B) are each an anion exchange membrane or a cation exchange membrane; when the membrane stack (4) ) is a bipolar membrane stack, the first ion exchange membrane (A) and the second ion exchange membrane (B) are each an anion exchange membrane or a bipolar membrane. 5. The system according to any one of claims 2-4, wherein, the organic amine liquid circulation loop is also connected with an organic amine liquid output pipeline for outputting the organic amine liquid for removing thermally stable salts to The organic amine liquid reuse system, the organic amine liquid output line is provided with a third regulating valve (63), and the demineralized water circulation loop is also connected with a waste liquid discharge line for discharging waste liquid to the Outside the system, a fourth regulating valve (64) is provided on the waste liquid discharge line, and the control center (5) is also used to receive data from the first conductivity meter (91) and/or the second conductivity the conductivity signal of the meter (92), and adjust the third regulating valve (63) and/or all the The opening of the fourth regulating valve (64). 6. The system according to any one of claims 2-4, wherein the organic amine liquid circulation loop is provided with a first circulation pump (71), and the electrode liquid circulation loop is provided with a second circulation pump (71). 72), a third circulating pump (73) is provided in the demineralized water circulation loop, respectively for circulating the material in the organic amine liquid storage device (1) into the amine liquid chamber (4) of the membrane stack (4). II), the material in the electrode liquid storage device (2) is circulated and pumped into the anode chamber (I-1) and the cathode chamber (I-2) of the membrane stack (4), and the material in the demineralized water storage device (3) Circulating and pumping into the waste liquid chamber (III) of the membrane stack (4); Preferably, a filter is also provided on the connecting line of each circulating pump to the corresponding compartment of the membrane stack (4); More preferably, the filter is a cartridge filter with a filtration precision of 0.1-1 micron. 7. The system according to any one of claims 2-4, wherein the organic amine liquid inlet, the waste liquid inlet and the electrode liquid inlet of the membrane stack (4) are respectively provided with a heat exchanger and a thermometer, It is used to regulate the temperature of the material entering the membrane stack (4). 8. The system according to any one of claims 2-4, wherein the system is further provided with a lye input device, and the conveying pipeline of the lye input device is connected to the organic amine solution storage device (1) . 9. The system according to any one of claims 2-4, wherein the system is also provided with an inert gas access device, and the conveying pipeline of the inert gas access device is respectively connected to the organic amine liquid storage device (1 ), electrode fluid storage device (2) and demineralized water storage device (3). 10. A method for treating an organic amine liquid containing a thermally stable salt using the system for removing thermally stable salts in an organic amine liquid according to any one of claims 1 to 9, wherein the method comprises treating the organic amine liquid to be The processing organic amine liquid is introduced into the organic amine liquid storage device (1) of the system through an external pipeline, the demineralized water is introduced into the demineralized water storage device (3) of the system, and the electrode liquid storage device (2) is passed through Electrode solution, then the organic amine solution is circulated and pumped into the amine solution chamber (II) of the membrane stack (4), and the demineralized water in the demineralized water storage device (3) is circulated and pumped into the membrane stack ( 4) the waste liquid chamber (III), the electrode solution in the electrode solution storage device (2) is circulated and pumped into the anode chamber (1-1) and the cathode chamber (1-2) of the membrane stack (4) respectively; The anode plate and the cathode plate of the membrane stack (4) are respectively connected with the positive electrode and the negative electrode of the power supply, so that the organic amine solution to be treated that is pumped into the membrane stack (4) is circulated and subjected to heat-stable salt removal treatment to obtain a deionized solution. The heat-stable salt-removed organic amine solution and the heat-stable salt-enriched demineralized water, when the obtained heat-stable salt-removed organic amine solution and the heat-stable salt-enriched demineralized water meet the recovery and discharge standards respectively, are treated to obtain The heat-stable salt-removed organic amine liquid is transported to the organic amine liquid reuse system, and the heat-stable salt-enriched demineralized water obtained after the treatment is discharged to the outside of the system as a waste liquid. 11. The method according to claim 10, wherein the organic amine liquid to be treated is monoethanolamine containing thermostable salt, diethanolamine containing thermostable salt, N-methyldiethanolamine containing thermostable salt, containing Triethanolamine with heat-stable salt, N-methylethylenediamine with heat-stable salt, Diisopropanolamine with heat-stable salt, N,N-dibutylethanolamine with heat-stable salt, At least one of ethylenediamine, diethylamine containing thermostable salt, tetramethylethylenediamine containing thermostable salt, and piperazine containing thermostable salt. 12. The method according to claim 10, wherein, before the organic amine solution, the demineralized water and the electrode solution enter the membrane stack (4), heat exchange treatment is performed, and the organic amine solution, demineralized water solution after heat exchange treatment and the temperature of the electrode solution is 5-35°C, preferably 15-25°C.

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