CN116103067A - Alkoxypropylamine compound and application thereof in organic sulfur absorption and removal - Google Patents

Abstract

The invention relates to an alkoxypropylamine compound and its application in the absorption and removal of organic sulfur. The compound has the following structural formula:

In the formula, R ₁ is a C1-6 alkyl substituent, and R ₂ is H or a C1-3 alkyl substituent. Compared with the prior art, the alkoxypropylamine compounds in the present invention have a better deep removal effect on various types of sulfides, and the chemical properties of these compounds are stable, not easy to decompose, the bubble point vapor pressure is small, and the volatile It has less loss, weak alkalinity, and light corrosion to equipment, so it has good industrial application prospects.

Description

A kind of alkoxypropylamine compound and its application in the absorption and removal of organic sulfur

technical field

The invention belongs to the technical field of gas desulfurization and purification, and relates to an alkoxypropylamine compound and its application in the absorption and removal of organic sulfur.

Background technique

The sulfides contained in natural gas, oilfield associated gas, refinery gas, blast furnace gas and other streams include hydrogen sulfide and organic sulfides such _as COS, CS ₂ , mercaptans, sulfides, and disulfides; The pipelines are corroded and seriously endanger the health of users; COS and mercaptans are the main components of organic sulfur contained in natural gas. If they are not removed, on the one hand, it will cause catalyst poisoning in the downstream chemical process using natural gas as raw material. , on the other hand, COS and low molecular weight mercaptans discharged into the atmosphere without treatment can form SO ₂ , promote photochemical reactions, and cause serious environmental problems. At the same time, these sulfur compounds have an unbearable odor even at extremely low concentration levels. Therefore, the acidic components, especially sulfides, must be removed to a specific value before the natural gas is transported into pipelines. For example, the newly promulgated "Natural Gas" standard GB17820-2018 stipulates that H ₂ S ≤ 6mg/Nm ³ and total sulfur ≤ 20mg/Nm ³ in civil natural gas in China; H ₂ S ≤ 20mg/Nm ³ in second-class natural gas ≤100mg/Nm ³ .

Refinery gas is one of the products of refinery units. According to different refining processes, it can be divided into catalytic dry gas and liquefied gas, coking dry gas and liquefied gas, catalytic cracking liquefied gas, etc. Since crude oil contains sulfur elements, these gas phase products also contain different forms of sulfides, usually containing organic sulfur such as H ₂ S and COS, mercaptans, and sulfides. Refinery gas can be used both as a fuel for refinery process furnaces and as a feedstock for downstream chemical processes. Sulphides in refinery gas will produce SO ₂ after being burned in the heating furnace, which will cause serious air pollution when discharged into the atmosphere. Sulfides in refinery gas can also corrode equipment and pipelines, reduce their service life, and cause potential safety hazards. When used as chemical raw materials, sulfides in refinery gas can also cause catalyst poisoning in downstream processes, shorten the operating cycle of process units, increase additional production costs, and sulfides can also pollute downstream products, resulting in substandard product quality . Therefore, the sulfide contained in the refinery gas must be removed to a certain level before being further processed and utilized. Among them, "Petroleum Refining Industrial Pollutant Discharge Standard" GB31570-2015 clearly stipulates that the SO ₂ emission limit of the refinery process heating furnace is 50mg/ ^m3 , and "Liquefied Petroleum Gas" GB 11174-2011 clearly stipulates the total sulfur content in commercial liquefied petroleum gas Not more than 343mg/m ³ , hydrogen sulfide not more than 10mg/m ³ . In addition, blast furnace gas is an important fuel, and sulfur compounds such as hydrogen sulfide and COS contained in it also need to be effectively removed to strictly control the SO ₂ content of flue gas emitted from the combustion furnace.

The absorption method using alkanolamine as a solvent is an effective method to remove these acidic components. Commonly used alcoholamines include monoethanolamine (MEA), diethanolamine (DEA), methylmonoethanolamine (MMEA), diethylethanolamine ( DEEA), triethanolamine (TEA), diisopropanolamine (DIPA), diglycolamine (DGA) and N-methyldiethanolamine (MDEA). Using traditional alcohol amine solvents, as long as the device design is reasonable and the process conditions are appropriate, the H ₂ S and CO ₂ in the raw gas can generally be removed to the required level, but the removal efficiency of organic sulfur such as COS and mercaptans depends on the The nature of the solvent is different and the difference is very different. The removal efficiency of traditional alcohol amine solvents for organic sulfur is low, and the removal rates of MEA and DEA with strong alkalinity for methyl mercaptan, ethanethiol and propanethiol are only 100%. About 45%-50%, 20-25% and 0-10%. In addition, since _H2S and _CO2 are more acidic than COS and organic sulfides such as mercaptans, the preferential dissolution of a large amount of _H2S and _CO2 components in alcohol amine solvents will further reduce the solubility of organic sulfur components. Therefore, under the conditions of high concentrations of H ₂ S and CO ₂ , as well as high concentrations of COS and mercaptans and other organic sulfides in sour oil and natural gas, it is usually difficult to effectively remove high concentrations of The simultaneous removal of H ₂ S and CO ₂ can achieve the effective removal of higher content organic sulfides.

Although the concentration of H ₂ S and CO ₂ in the refinery gas is at a moderate level, the concentration of organic sulfur such as mercaptans is high, and acidic components such as H ₂ S, CO ₂ and COS can be effectively removed by chemical absorption, while It is difficult to effectively reduce the content of organic sulfur such as mercaptans and other organic sulfur mainly relying on physical dissolution and only relying on alcohol amine solvents. At present, refineries generally adopt the combination process of amine washing and alkali washing to reduce the mercaptan content in the liquefied gas to the target range in order to solve the problem of high mercaptan content in the liquefied gas of the refinery. The liquefied gas after H ₂ S, CO ₂ and some organic sulfur is introduced into the alkali washing tower again, and the lye and the liquefied gas are in countercurrent contact. Therefore, the content of mercaptan in the liquefied gas is reduced, and the total sulfur content of the liquefied gas is further reduced. Compared with the simple amine washing process, this process has achieved remarkable results in reducing the total sulfur content of liquefied gas, but it also has many shortcomings. The first is the discharge and treatment of spent alkali, although the alkali in this process can be passed through Solvent back extraction is used for in-life treatment, but the accumulation of sulfur-containing compounds is still unavoidable. After a period of recycling and regeneration treatment, the efficiency of the regenerated lye to remove mercaptans in liquefied gas is significantly reduced, and it has to be replaced. The discharged waste lye and alkali slag emit foul smell due to the sulfide and other sulfides contained therein, and because of its alkaline nature, improper treatment will also cause environmental pollution. In addition, the disulfide contained in the alkali liquor regeneration process cannot be completely removed by the back extraction solvent. When it returns to the contact tower to contact the liquefied gas, the disulfide is back extracted by the liquefied gas instead, resulting in liquefied gas The total sulfur removal effect cannot be effectively improved. Alkaline washing can only effectively remove mercaptan organic sulfur, and the removal effect on other organic sulfur is not obvious, and the application range is too limited. As the types of organic sulfur components in liquefied gas become more complex and their content increases, the advantages of this process will be further weakened. In addition, the combined process of amine washing and alkali washing increases the complexity of the process and the cost of equipment investment, operation and maintenance.

Improving the selective desulfurization performance of solvents is an effective way to solve the desulfurization problems of natural gas, oilfield associated gas, refinery gas, and blast furnace gas. In order to improve the removal efficiency of organic sulfur by alkanolamine solvents, most workers improve the removal effect of organic sulfur by adding an appropriate amount of auxiliary solvent to the solvent mainly composed of MDEA or DIPA, in order to further reduce the purification of petroleum The total sulfur content in natural gas meets the relevant index requirements.

In the patent CN 102051244A, in consideration of the high content of organic sulfur such as COS in highly acidic oil and natural gas, in order to effectively remove organic sulfur components such as COS, the solvent composition design is specially added to effectively catalyze COS hydrolysis, chemical absorption and physical dissolution. Active components except for organic sulfides such as COS and mercaptans. The high-efficiency purification and desulfurization agent for high-acid oil and natural gas composed of these active components has good organic sulfur removal performance. It can effectively remove high-concentration H ₂ S and efficiently remove high-content organic It shows obvious advantages in oil and gas with high sulfur content, especially high organic sulfur content. However, its organic sulfur solubility and removal efficiency still need to be further improved.

Patent CN102580473A discloses a new type of polyamide-amine dendrimers with high desulfurization selectivity and an aqueous solution formed by mixing alcohol amines as an absorbent, wherein the mass fraction of polyamide-amine dendrimers is 1% to 15% , the mass fraction of alkanolamine is 50%-10%. The absorbent has better H ₂ S removal selectivity and higher organic sulfur removal rate than conventional alcohol amine solvents.

Patent CN101507891B discloses a liquid composition for removing sulfide in gas, which is composed of absorbent, auxiliary agent and defoamer; wherein, the absorbent is composed of sterically hindered amine and alkanolamine; the auxiliary The antifoaming agent is one of thiazoles or aliphatic amines and phenols or a mixture thereof; the defoaming agent is siloxane, and the liquid composition can effectively remove organic and inorganic sulfur in the gas at the same time.

Patent CN105381686A discloses an absorbent solution for absorbing acid gas and a method for absorbing acid gas. Under the premise of ensuring efficient removal of H ₂ S, the main body of the absorption solution is benzylamine and benzylamine derivatives. According to It is reported that this solvent and method can significantly reduce the vapor pressure of aniline compounds and enhance its removal effect on COS and mercaptans when used.

However, most of the methods disclosed above are based on alkanolamine (N-methyldiethanolamine, triisopropanolamine) as the main solvent, and are improved on the basis of the original alkanolamine by preferably modifying agents such as hindered amines. For the removal efficiency of organic sulfur, the gas objects containing organic sulfur that they can handle are relatively fixed, and usually cannot meet the complex and changeable organic sulfur removal requirements in different raw materials.

In order to meet the increasingly stringent requirements for the removal of total sulfur, it is necessary to further optimize the solvent components and composition to improve the absorption and solubility of different types of organic sulfur and achieve deep removal of various types of sulfides.

Contents of the invention

The object of the present invention is to provide an alkoxypropylamine compound and its application in the absorption and removal of organic sulfur. The alkoxypropylamine compound in the present invention has a good deep removal effect on various types of sulfides, and the compound has stable chemical properties, is not easy to decompose, has a small bubble point vapor pressure, less volatilization loss, and weak alkalinity. It has light corrosion to equipment, so it has good industrial application prospect.

The purpose of the present invention can be achieved through the following technical solutions:

An alkoxypropylamine compound has the following structural formula:

In the formula, R ₁ is a C1-6 alkyl substituent, and R ₂ is H or a C1-3 alkyl substituent.

Further, said R ₁ is a C3-5 alkyl substituent.

Further, the compound is one of 3-propoxypropylamine, 3-isopropoxypropylamine, 3-butoxypropylamine, 3-isobutoxypropylamine or 3-isoamyloxypropylamine or A mixture of several.

The application of an alkoxypropylamine compound comprises using the compound for removing organic sulfur in the gas phase.

Further, the gas phase includes one of oilfield associated gas, refinery gas or blast furnace gas.

Further, the organic sulfur includes at least one of hydrogen sulfide, COS, CS ₂ , mercaptan, thioether or disulfide.

Further, the compound is formulated into an aqueous solution with a mass fraction of 5-60% as an organic sulfur absorption liquid.

Further, the compound and the organic amine are mixed at a mass ratio of (1-99):(99-1) to obtain a mixed amine, which is then formulated into an aqueous solution with a mass fraction of the mixed amine of 5-75% as an organic sulfur absorption liquid ;

The organic amines include at least one of alkylamines, alkanolamines, amides, phosphoramides, benzylamines and derivatives thereof, or nitrogen-containing heterocyclic aromatic compounds.

Further, the organic amine includes at least one of monoethanolamine, diethanolamine, diisopropanolamine, diglycolamine or N-methyldiethanolamine.

Further, the mixing mass ratio of the compound to the organic amine is (10-90):(90-10), and the mass fraction of the mixed amine in the organic sulfur absorption liquid is 15-50%.

Compared with the prior art, the present invention has the following characteristics:

1) The alkoxy group in the alkoxypropylamine compound of the present invention makes the electron density on the nitrogen atom of the oxygen atom and propylamine increase due to the electron-donating effect of the alkane group, and the primary in the alkoxypropylamine The group activity of the amine group can serve as a potential hydrogen bond donor and hydrogen bond acceptor at the same time, which can attract and capture organic sulfur molecules such as thiol and thioether. The strong electronic effect makes the alkoxypropylamine compound have a stronger The interaction between organic sulfur molecules, and the branched chain structure where alkoxy groups can exist can capture organic sulfur molecules through the van der Waals effect. Therefore, at the molecular level, this type of compound can effectively improve the solubility of organic sulfur, so as to achieve the purification of total sulfur in gas products. Reach a lower level and meet the requirements of different raw material sulfide composition, processing conditions and desulfurization indicators.

2) Compared with polyamine-based compounds, the alkoxypropylamine compounds of the present invention have lower synthesis cost and more economic advantages, lower bubble point pressure in aqueous solution, and lower volatilization loss when recycled in the absorption-regeneration system. Less; compared with aniline compounds, alkoxypropylamine has better chemical stability, is not easy to decompose and deteriorate, and the aqueous solution is more alkaline and less acidic, which can reduce equipment corrosion.

Taking 3-butoxypropylamine as an example, the bubble point vapor pressure is 112.4Pa, which is lower than the bubble point vapor pressure 204.1Pa of diethylaminopropylamine with a similar boiling point, and the evaporation loss of 3-butoxypropylamine is lower; it has been reported The 4-methoxybenzylamine needs to be stored away from light at room temperature, and it is easy to deteriorate in the air, while the 3-butoxypropylamine has no special requirements for storage conditions, and has more excellent thermal and chemical stability; after determination, 10wt The pH values of 3-butoxypropylamine, diethylaminopropylamine and 4-methoxybenzylamine aqueous solution are respectively 11.4, 11.5 and 12.0, and the alkalinity of 3-butoxypropylamine is weaker, more corrosion to equipment light.

Description of drawings

Fig. 1 is the structural representation of the measurement experimental device of methyl mercaptan in the desulfurization solvent component in the present invention equilibrium solubility;

Description of markings in Figure 1:

1-methane gas cylinder; 2-acid gas cylinder; 3-constant temperature water bath; 4-stainless steel reaction kettle; 5-magnetic stirrer; 6-air pressure test device; 7-water bath temperature control device; 8-needle valve; 9 - mechanical stirrer;

Fig. 2 is the structural representation among the present invention;

Description of markings in Figure 2:

1-raw material gas; 2-purified gas; 3-flash gas; 4-acid gas; 5-absorption tower rich liquid; 6-flash tank rich liquid; 7-heat exchanger rich liquid; 8-regeneration tower 9- lean liquid out of heat exchanger; 10- lean liquid out of cooler; 11- absorption tower; 12- rich liquid flash tank; 13- regeneration tower; 14- regeneration lean liquid cooler; 15- lean Rich liquid heat exchanger; 16 - regeneration tower top condenser; 17 - regeneration tower bottom reboiler.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

An alkoxypropylamine compound has the following structural formula:

In the formula, R ₁ is a C1-6 alkyl substituent, and R ₂ is H or a C1-3 alkyl substituent.

In some specific embodiments, the alkoxypropylamine compound is a mixture of one or more long-chain propylamines with an alkoxy group with a certain number of carbons. Preferably, in the molecule of the alkoxypropylamine compound, R ₁ The positions are alkoxy with 3-5 carbons, and propylamine possibly with an alkyl substituent in the alpha position ( _R2 position). These compounds have good water solubility and are convenient to prepare solutions; they have better thermal stability and chemical stability than benzylamine compounds, and are not easy to decompose; the bubble point vapor pressure is low, and the volatilization loss of more amino compounds is smaller; and the aqueous solution is alkaline Weak, less corrosive than other amine solvents.

In some specific embodiments, the alkoxypropylamine compound is 3-propoxypropylamine, 3-isopropoxypropylamine, 3-butoxypropylamine, 3-isobutoxypropylamine or 3-isoamyloxy One or more mixtures of propylamines; preferably 3-isopropoxypropylamine, 3-isobutoxypropylamine.

The application of an alkoxypropylamine compound comprises that the compound is used for removing organic sulfur in the gas phase. Specifically, the compound is used to remove organic sulfides in oil field associated gas, refinery gas or blast furnace gas. Among them, the organic sulfide is preferably one or more mixtures of carbonyl sulfide and mercaptans, thioethers or disulfides with 1 to 4 carbon atoms. More preferred are hydrogen sulfide, COS, CS ₂ , mercaptan, thioether, or disulfide.

Among them, natural gas, oilfield associated gas, refinery gas, and blast furnace gas contain up to about 8 (mol)% H ₂ S and about 3000 mg (calculated as sulfur element)/Nm ³ organic sulfur. When dealing with natural gas, oilfield associated gas, refinery gas, blast furnace gas and other logistics, the raw material gas treatment load can be higher, and the absorption pressure can be lower. Under the premise of ensuring that the purification effect of H ₂ S and COS in the logistics reaches the relevant indicators, Significantly reduce the total sulfur content in the purified gas by significantly increasing the solubility of the desulfurization solvent to organic sulfides such as methyl mercaptan.

In some specific embodiments, the compound is prepared as an aqueous solution with a mass fraction of 5-60% as an organic sulfur absorption liquid.

In some specific embodiments, the compound is mixed with an organic amine at a mass ratio of (1-99):(99-1) to obtain a mixed amine, and then the mixed amine mass fraction is 5-75% to prepare an aqueous solution as Organic sulfur absorbing liquid; wherein the organic amines include at least one of alkylamines, alkanolamines, amides, phosphoramides, benzylamines and derivatives thereof, or nitrogen-containing heterocyclic aromatic compounds.

In some specific embodiments, the organic amine includes at least one of monoethanolamine, diethanolamine, diisopropanolamine, diglycolamine or N-methyldiethanolamine; preferably diisopropanolamine, N- Methyldiethanolamine.

In some specific embodiments, the mixed amine is supported by the compound and the organic amine in a mixed mass ratio (10-90):(90-10), and in the organic sulfur absorption liquid, the mass fraction of the mixed amine is 15-50 %.

The invention provides an alkoxypropylamine compound, which can efficiently and selectively purify and remove hydrogen sulfide and various types of organic sulfides such as COS, CS ₂ , mercaptan, sulfide, disulfide, etc. When the content of organic sulfur in raw material gases such as gas, refinery gas, and blast furnace gas is particularly high, it can effectively reduce the content of H ₂ S and total sulfur in the stream at the same time. After absorption test evaluation, the absorbent of this type of compound has excellent organic sulfur content. Sulfur absorption solubility and removal efficiency, while having better chemical stability compared with the benzylamine compounds disclosed in existing patents, and having smaller evaporation loss compared with the disclosed amine-based compounds, its Aqueous solutions are less corrosive.

The following examples are carried out on the premise of the technical solutions of the present invention, and detailed implementation methods and specific operation processes are provided, but the protection scope of the present invention is not limited to the following examples.

The present invention has discovered an alkoxypropylamine compound capable of efficiently and selectively purifying and removing organic sulfides such as hydrogen sulfide and COS, CS ₂ , mercaptan, sulfide, disulfide, etc., hereinafter referred to as 3-isopropoxy Propylamine and 3-butoxypropylamine, with the performance contrast of traditional solvent N-methyldiethanolamine as an example to illustrate the advantages of the present invention:

The measuring experimental device of the equilibrium solubility of methyl mercaptan in the desulfurization solvent component is as shown in accompanying drawing 1, comprises stainless steel reactor 4, is located at the constant temperature water bath 3 outside stainless steel reactor 4, and the water that is electrically connected with constant temperature water bath 3 Bath temperature control device 7, a magnetic stirrer 5 located at the bottom of the constant temperature water bath 3 and compatible with the magnet in the stainless steel reactor 4, a methane gas cylinder 1 and an acid gas cylinder 2 connected with the stainless steel reactor 4, The mechanical stirrer 9 and the air pressure test device 6 arranged on the stainless steel reaction kettle 4, the vacuum tube arranged between the vacuum pump and the stainless steel reaction kettle 4, the absorption liquid injected between the organic sulfur absorption liquid storage tank and the stainless steel reaction kettle 4 tube, and the needle valve 8 respectively arranged on the vacuum tube and the absorption liquid injection tube.

Among them, the stainless steel reaction kettle 4 has a volume of 250mL, and the temperature control accuracy is ±0.2°C; the methane gas cylinder 1 is filled with pure methane gas, and the acid gas cylinder 2 is filled with pure gaseous methyl mercaptan. Before the experiment, test the pressure with nitrogen, then add 50-100mL of the desulfurization solvent component to be tested into the equilibrium reaction kettle, and fully replace the nitrogen in the kettle with methane after sealing. Turn on the constant temperature water bath and adjust it to the temperature required for the experiment. After the temperature rises to the set value, fill it with a certain partial pressure of methyl mercaptan. The total pressure of the system is maintained by methane, and turn on the gas-liquid double drive to stir. After the system reaches each equilibrium point, a micro sample is taken to analyze the concentration of methyl mercaptan in the gas-liquid two-phase, and the Henry constant is calculated according to the gas-liquid equilibrium relationship H=P _e /X _e as an index to measure the ability of the solvent to dissolve methyl mercaptan.

The absorption method is used to remove sulfur in the raw material gas. The purification process of the absorption method is shown in Figure 2. The raw material gas 1 is discharged from the top of the tower after being contacted with the absorption liquid in the absorption tower 11 in reverse phase to remove the acidic components, and the acidic components are absorbed. The separated rich liquid 5 comes out from the bottom of the tower and then enters the rich liquid flash tank 12 to flash dissolve the dissolved hydrocarbons. After the flash evaporation, the rich liquid 6 exchanges heat with the regenerated lean liquid in the heat exchanger 15, and then enters the regeneration tower 13 desorption regeneration. The acid gas 4 is discharged from the top of the regeneration tower and then sent to the sulfur recovery device to recover sulfur. The poor regeneration liquid is discharged from the bottom of the tower, cooled by the heat exchanger 15 and the cooler 14, and then returned to the absorption tower 11 for recycling.

Concretely adopted feed gas composition and absorption solution composition are as follows:

Example 1

At 30°C, the Henry coefficient of methylmercaptan dissolved in 3-isopropoxypropylamine is 82.14kPa; at 40°C, the Henry coefficient of methylmercaptan dissolved in 3-isopropoxypropylamine is 213.06kPa; at 50°C Under the following conditions, the Henry coefficient of methylmercaptan dissolved in 3-isopropoxypropylamine is 367.29kPa.

At 30°C, the Henry coefficient of methylmercaptan dissolved in 3-butoxypropylamine is 104.7kPa; at 40°C, the Henry coefficient of methylmercaptan dissolved in 3-butoxypropylamine is 290.0kPa; at 50°C, The Henry coefficient of methylmercaptan dissolved in 3-butoxypropylamine is 395.6kPa.

Example 2

At 30°C, the Henry constant of methylmercaptan in 3-isopropoxypropylamine calculated using COSMO-RS theory is 133.9kPa, and the Henry constant of dimethyl sulfide in 3-isopropoxypropylamine is 92.51kPa, The Henry constant of COS in 3-isopropoxypropylamine is 1827kPa, and the Henry constant of CS ₂ in 3-isopropoxypropylamine is 356.2kPa. At a gas-liquid ratio of 50:1 and under normal pressure conditions, 3-isopropoxypropylamine is used to treat natural gas containing 3000mg/ ^Nm3 (the content is all in S, the same below) of the organic sulfur mentioned above, and after reaching the dissolution equilibrium The removal rates of methyl mercaptan, dimethyl sulfide, COS and CS ₂ were 77.1%, 82.1%, 82.7% and 81.7%, respectively.

At 30°C, the Henry constant of methylmercaptan in 3-butoxypropylamine calculated using COSMO-RS theory is 160.9kPa, the Henry constant of dimethyl sulfide in 3-butoxypropylamine is 106.5kPa, and COS is in The Henry constant in 3-butoxypropylamine is 1975kPa, and the Henry constant of CS ₂ in 3-butoxypropylamine is 406.7kPa. At a gas-liquid ratio of 50:1 and under normal pressure conditions, 3-butoxypropylamine is used to treat natural gas containing 3000mg/ ^Nm3 (the contents are all in S, the same below) of the organic sulfur mentioned above to reach the dissolved equilibrium. The removal rates of methyl mercaptan, dimethyl sulfide, COS and CS ₂ were 76.3%, 79.7%, 81.2% and 81.0%, respectively.

Example 3

Raw material gas with the following composition: total organic sulfur content 2500mg/Nm ³ (of which COS 500mg/Nm ³ , methyl mercaptan 1000mg/Nm ³ , ethanethiol 500mg/Nm ³ , dimethyl sulfide 500mg/Nm ³ ), The _H2S content is 5.0 mol%, and the _CO2 content is 5.0 mol%.

An absorption solution with the following composition (both mass fractions) is adopted: 40% of 3-butoxypropylamine, the rest is water, and the sum of the contents of each component is 1. The absorption temperature is 40°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.20L/h. The content of H ₂ S in the purified gas is less than 5mg/Nm ³ , the content of CO ₂ is less than 100ppm(v), the content of methyl mercaptan and COS is 0, and the removal rate of total organic sulfur is 88.27%.

Example 4

Raw material gas with the following composition: total organic sulfur content 2500mg/Nm ³ (of which COS 500mg/Nm ³ , methyl mercaptan 1000mg/Nm ³ , ethanethiol 500mg/Nm ³ , dimethyl sulfide 500mg/Nm ³ ), The _H2S content is 5.0 mol%, and the _CO2 content is 5.0 mol%.

An absorption solution with the following composition (both mass fractions) is adopted: 12% of 3-isopropoxypropylamine, 28% of N-methyldiethanolamine, and the rest is water, and the sum of the contents of each component is 1. The absorption temperature is 25°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.20L/h. The content of H ₂ S in the purified gas is less than 1mg/Nm ³ , the content of CO ₂ is less than 150ppm(v), the content of methyl mercaptan and COS is 0, and the removal rate of total organic sulfur is 89.15%.

Example 5

Raw material gas with the following composition: total organic sulfur content 2500mg/Nm ³ (of which COS 500mg/Nm ³ , methyl mercaptan 1000mg/Nm ³ , ethanethiol 500mg/Nm ³ , dimethyl sulfide 500mg/Nm ³ ), The _H2S content is 5.0 mol%, and the _CO2 content is 5.0 mol%.

An absorption solution with the following composition (all mass fractions) was adopted: 12% of 3-butoxypropylamine, 28% of N-methyldiethanolamine, and the rest was water, and the sum of the contents of each component was 1. The absorption temperature is 40°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.20L/h. The content of H ₂ S in the purified gas is less than 1mg/Nm ³ , the content of CO ₂ is less than 1000ppm(v), the content of methyl mercaptan and COS is 0, and the removal rate of total organic sulfur is 88.33%.

Example 6

Raw material gas with the following composition: total organic sulfur content 4859mg/Nm ³ (of which COS 714.5mg/Nm ³ , methyl mercaptan 2143mg/Nm ³ , ethanethiol 714.5mg/Nm ³ , propanethiol 429mg/Nm ³ , di Methyl disulfide 858mg/Nm ³ ), H ₂ S content is 2000mg/Nm ³ .

An absorption solution with the following composition (both mass fractions) was adopted: 12% of 3-isopropoxypropylamine, 28% of N-methyldiethanolamine, the rest was water, and the sum of the contents of each component was 1. The absorption temperature is 40°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.30L/h. The content of H ₂ S in the purified gas is less than 1mg/Nm ³ , the content of methyl mercaptan is less than 100mg/Nm ³ , the content of COS is less than 50mg/Nm ³ , and the removal rate of total organic sulfur is 82.3%.

Example 7

Raw material gas with the following composition: total organic sulfur content 4859mg/Nm ³ (of which COS 714.5mg/Nm ³ , methyl mercaptan 2143mg/Nm ³ , ethanethiol 714.5mg/Nm ³ , propanethiol 429mg/Nm ³ , di Methyl disulfide 858mg/Nm ³ ), H ₂ S content is 2000mg/Nm ³ .

An absorption solution with the following composition (both mass fractions) was adopted: 12% of 3-butoxypropylamine, 28% of N-methyldiethanolamine, the rest was water, and the sum of the contents of each component was 1. The absorption temperature is 40°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.30L/h. The content of H ₂ S in the purified gas is less than 1mg/Nm ³ , the content of methyl mercaptan is less than 150mg/Nm ³ , the content of COS is less than 80mg/Nm ³ , and the removal rate of total organic sulfur is 79.47%.

Comparative example 1

At 30°C, the Henry constant of methylmercaptan in N-methyldiethanolamine calculated using COSMO-RS theory is 398.6kPa, the Henry constant of dimethyl sulfide in N-methyldiethanolamine is 309.7kPa, and COS is The Henry constant in N-methyldiethanolamine is 5523kPa, and the Henry constant in CS ₂ in N-methyldiethanolamine is 1182kPa.

Comparative example 2

Raw material gas with the following composition: total organic sulfur content 2500mg/Nm ³ (of which COS 500mg/Nm ³ , methyl mercaptan 1000mg/Nm ³ , ethanethiol 500mg/Nm ³ , dimethyl sulfide 500mg/Nm ³ ), The _H2S content is 5.0 mol%, and the _CO2 content is 5.0 mol%.

An absorbing solution with the following composition (both mass fractions) is adopted: 40% of N-methyldiethanolamine, the rest is water, and the sum of the contents of each component is 1. The absorption temperature is 40°C, the absorption pressure is 101.325kPa, the feed gas flow rate is 60.0L/h, and the absorption liquid circulation rate is 0.20L/h. The content of H ₂ S in the purified gas is 0, the content of CO ₂ is less than 3%, the removal rate of methyl mercaptan and COS is less than 20%, and the removal rate of total organic sulfur is 28.10%.

It can be seen from the examples and comparative examples that the alkoxypropylamine compounds of the present invention have higher organic sulfur solubility and removal efficiency than the existing organic alcohol amine compounds, and help to deal with high organic sulfur content, To absorb the demand for desulfurization of feed gas with low pressure.

The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative efforts. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (10)

1. An alkoxypropylamine compound, characterized in that the compound has the following structural formula:

wherein R is ₁ Is C1-6 alkyl substituent, R ₂ Is H or alkyl substituent of C1-3.

2. An alkoxypropylamine compound according to claim 1, wherein R is ₁ Is an alkyl substituent of 3 to 5 carbon atoms.

3. An alkoxypropylamine compound according to claim 1, wherein said compound is one or a mixture of 3-propoxypropylamine, 3-isopropoxypropylamine, 3-butoxypropylamine, 3-isobutoxypropylamine or 3-isopentoxypropylamine.

4. Use of an alkoxypropylamine compound according to any of claims 1 to 3, wherein said compound is free of organic sulfur in the gas phase.

5. The use of an alkoxypropylamine compound according to claim 4, wherein said gas phase comprises one of an oilfield associated gas, a refinery gas, or a blast furnace gas.

6. The use of an alkoxypropylamine compound according to claim 4, wherein said organosulfur comprises hydrogen sulfide, COS, CS ₂ At least one of a thiol, thioether, or disulfide.

7. The use of an alkoxypropylamine compound according to claim 4, wherein said compound is formulated as an aqueous solution of 5 to 60% by mass as an organic sulfur absorbent.

8. The application of the alkoxypropylamine compound according to claim 4, wherein the compound is mixed with organic amine according to the mass ratio of (1-99) (99-1) to obtain mixed amine, and the mixed amine is prepared into an aqueous solution according to the mass fraction of 5-75% to be used as an organic sulfur absorption liquid;

the organic amine comprises at least one of alkylamine, alkanolamine, amide, phosphoramide, benzylamine and derivatives thereof or nitrogen-containing heterocyclic aromatic compounds.

9. The use of an alkoxypropylamine compound according to claim 8, wherein said organic amine comprises at least one of monoethanolamine, diethanolamine, diisopropanolamine, diglycolamine, or N-methyldiethanolamine.

10. The application of the alkoxypropylamine compound according to claim 9, wherein the mixing mass ratio of the compound to the organic amine is (10-90): (90-10), and the mass fraction of the mixed amine in the organic sulfur absorbing solution is 15-50%.

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