CN110937975A - Method and system for preparing propylene - Google Patents
Method and system for preparing propylene Download PDFInfo
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- CN110937975A CN110937975A CN201811117818.6A CN201811117818A CN110937975A CN 110937975 A CN110937975 A CN 110937975A CN 201811117818 A CN201811117818 A CN 201811117818A CN 110937975 A CN110937975 A CN 110937975A
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- C07C5/32—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with formation of free hydrogen
- C07C5/327—Formation of non-aromatic carbon-to-carbon double bonds only
- C07C5/333—Catalytic processes
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Abstract
The present disclosure relates to a process and system for producing propylene, the process comprising the steps of: carrying out MAPD (methyl acrylamide) hydrotreating on a propane raw material to obtain a hydrotreated material; carrying out weight removal treatment on the hydrotreated material to remove heavy components containing more than 4 carbon atoms so as to obtain a weight-removed material; carrying out PDH dehydrogenation treatment on the material subjected to the de-weighting treatment to obtain a material subjected to PDH dehydrogenation treatment; after removing hydrogen and ethane from the material subjected to PDH dehydrogenation treatment, carrying out rectification treatment to obtain distilled propylene and a second distillation residue material; subjecting the second bottoms material to the MAPD hydroprocessing with the propane feedstock. The method can overcome the problems of unstable operation, high energy consumption and large investment of the device in the prior method, eliminate the limitation of raw material purchase on the contents of the methylacetylene and the propadiene, and reduce the separation difficulty.
Description
Technical Field
The present disclosure relates to the field of chemical engineering, and in particular, to a process and system for producing propylene.
Background
In the traditional process flow for preparing propylene, raw material liquid-phase propane enters a cold separation system after being pretreated and subjected to removal of four heavy components such as carbon and the like, and is vaporized after heat exchange, throttling and pressure reduction in the cold separation system and enters a propane dehydrogenation unit; the discharged material of the propane dehydrogenation unit is sent into a cold separation system after being compressed by gas and removed with impurities; crude hydrogen separated by the cold separation system enters a crude hydrogen compression and pressure swing adsorption purification unit, hydrogen is purified to 99.99% v, tail gas obtained by crude hydrogen compression and pressure swing adsorption purification is used as fuel gas and introduced into a propane dehydrogenation unit, a carbon material flow separated by the cold separation system is sent into a deethanizer system after hydrogenation, and the MAPD hydrogenation position is located between the cold separation system and the deethanizer system. The light component separated from the top of the deethanizer is also used as a part of fuel gas and sent to a propane dehydrogenation unit, and the three carbon components in the deethanizer enter a propylene rectifying tower for separation, so that a qualified propylene product is obtained. The propane in the bottom of the propylene tower is combined with the pretreated fresh raw material propane and then enters a depropanization unit.
Studies have shown that Methylacetylene (MA) and Propadiene (PD) carried in the propane feed can cause coking of the dehydrogenation catalyst to plug equipment and affect plant operating stability. Therefore, the traditional propane dehydrogenation separation process has strict requirements on the contents of methylacetylene and propadiene in the feed, and has the problems of unstable device operation, high energy consumption and large investment.
Disclosure of Invention
The method for preparing propylene aims to solve the problems of unstable operation, high energy consumption and large investment of a device in the existing method, eliminate the limitation of raw material purchase on the contents of methylacetylene and propadiene and reduce the separation difficulty.
In order to achieve the above object, a first aspect of the present disclosure provides a process for producing propylene, the process comprising the steps of:
(a) carrying out MAPD (methyl acrylamide) hydrotreating on the propane raw material to obtain a hydrotreated material;
(b) carrying out weight removal treatment on the hydrotreated material to remove heavy components containing more than 4 carbon atoms so as to obtain a weight-removed material;
(c) carrying out PDH dehydrogenation treatment on the material subjected to the de-weighting treatment to obtain a material subjected to PDH dehydrogenation treatment;
(d) after removing hydrogen and ethane from the material subjected to PDH dehydrogenation treatment, carrying out rectification treatment to obtain distilled propylene and a second distillation residue material;
(e) returning the second raffinate stream to step (a) for the MAPD hydroprocessing with the propane feedstock.
Optionally, the method comprises: the material after the weight removal treatment is used as a cooling medium to enter a cold separation device for heat exchange to obtain gaseous C3Material preparation; introducing said gaseous C3Carrying out the PDH dehydrogenation treatment on the material to obtain the material subjected to the PDH dehydrogenation treatment; feeding the material subjected to PDH dehydrogenation treatment into the cold separation device, and performing gas-liquid separation through heat exchange condensation and throttling depressurization to obtain liquid C3A material and crude hydrogen;
mixing the liquid C3Deethanizing the material in a deethanizer to obtain distilled C2A product and a first raffinate; introducing the first distillation residue material into a propylene rectifying device for rectifying treatment to obtain the distilled propylene and the second distillation residue material;
wherein the heat exchange cold in the cold separating deviceCondensing is primary condensation and/or fractional condensation; said liquid C3The feed of material to the deethanizer is a single feed and/or a multi-feed.
Optionally, the method comprises: carrying out crude hydrogen compression and pressure swing adsorption purification treatment on the crude hydrogen separated by the cold separation device to obtain purified hydrogen and tail gas, wherein the purity of the purified hydrogen is 99.0-99.999 volume percent, and the pressure is 1.5-2.5 MPa; the purified hydrogen was used as feed hydrogen for the MAPD hydroprocessing and the tail gas was used as fuel gas for the PDH dehydrogenation process.
Optionally, subjecting the propane feedstock to feedstock pretreatment to remove nitrogen oxides, heavy metals, and water from the propane feedstock prior to the MAPD hydrotreating; and/or
And (3) carrying out reaction gas compression and dehydrogenation impurity removal treatment on the material subjected to PDH dehydrogenation treatment, and then carrying out hydrogen removal treatment.
Optionally, the propane raw material contains propane, methylacetylene and propadiene, the content of the methylacetylene in the propane raw material is 50-1000ppm mol, and the content of the propadiene is 50-1000ppm mol
Optionally, the amount of hydrogen dosed for MAPD hydroprocessing is from 1.3 to 2.5.
A second aspect of the disclosure provides a system for producing propylene, the system comprising a propane feedstock inlet, a MAPD hydrogenation unit, a propane feedstock de-weighting unit, a PDH dehydrogenation unit, a cold separation unit, a deethanizer, a propylene rectification unit, and a propylene product outlet;
the propane raw material inlet, the MAPD hydrogenation device, the propane raw material de-weighting device and the PDH dehydrogenation device are sequentially connected, a dehydrogenation product outlet of the PDH dehydrogenation device is communicated with a material inlet of the cold separation device, a liquid product outlet of the cold separation device is communicated with a feed inlet of the deethanizer, a kettle liquid outlet of the deethanizer is communicated with a feed inlet of the propylene rectification device, a distillate outlet of the propylene rectification device is communicated with the propylene product outlet, and a raffinate outlet of the propylene rectification device is communicated with the propane raw material inlet.
Optionally, a distillate outlet of the propane feedstock de-weighting device is in communication with a cooling medium inlet of the cold separation device, and a cooling medium outlet of the cold separation device is in communication with a feedstock gas inlet of the PDH dehydrogenation device.
Optionally, the system further comprises a crude hydrogen compression and pressure swing adsorption purification device, a gas inlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with an uncondensed gas outlet of the cold separation device, a purified hydrogen outlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with a hydrogen inlet of the MAPD hydrogenation device, and a tail gas outlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with a fuel gas inlet of the PDH dehydrogenation device.
Optionally, the system further comprises:
a feedstock pretreatment unit disposed between the propane feedstock inlet and the MAPD hydrogenation unit; and/or
A reaction gas compression device and an impurity removal device which are connected in sequence, wherein a reaction gas inlet of the reaction gas compression device is communicated with a dehydrogenation product outlet of the PDH dehydrogenation device, and the impurity removal device C3The outlet of the material is communicated with the material inlet of the cold separation device.
The inventor of the disclosure finds that the MAPD content in the material obtained by PDH dehydrogenation is not high, and even if the material directly enters a subsequent propylene rectification unit, the impurity content of the propylene product obtained by rectification is still in a qualified range, namely the specification of the propylene product is not influenced. Therefore, according to the method and the system for preparing propylene, the propane raw material is subjected to MAPD (methyl acrylamide) hydrogenation treatment and then PDH (PDH) dehydrogenation treatment, so that the qualification of MAPD impurity content in a propylene product can be ensured;
secondly, the content of propylene in the material flow subjected to MAPD hydrogenation in the method and the system disclosed by the invention is low, the loss caused by simultaneous hydrogenation of propylene products in the material flow to be hydrogenated in the process of carrying out MAPD hydrogenation after PDH dehydrogenation in the prior art can be avoided, and the loss of target propylene products cannot be caused even if MAPD hydrogenation is excessive in the method disclosed by the invention;
thirdly, the MAPD hydrogenation and the PDH dehydrogenation are carried out in the method and the system, and then gas-liquid separation is carried out, so that light components generated in the hydrogenation and dehydrogenation steps can be removed, and light components such as excessive hydrogen and methane in MAPD hydrogenation products are prevented from entering a deethanizer, the load of the deethanizer is reduced, and the energy consumption of a device is reduced;
fourthly, the product selectivity of the MAPD hydrogenation catalyst in the method and the system of the disclosure is not required, the limitation of the hydrogenation reaction condition can be relaxed, and a little green oil generated by the hydrogenation device can be discharged through a subsequent de-weighting device without affecting the performance of the dehydrogenation catalyst;
fifthly, the material flow subjected to hydrogenation in the method and the system disclosed by the invention has low MAPD content and limited green oil generation, and the catalyst can be continuously used in at least one overhaul period (3-5 years) of the propane dehydrogenation device without regeneration, so that the MAPD hydrogenation device is not required to be provided with an online regeneration system and a standby reactor, the number of equipment is reduced, and the occupied area of the device is correspondingly reduced.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:
fig. 1 is a schematic process flow diagram of one embodiment of the disclosed process for producing propylene.
Detailed Description
The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
In the present disclosure, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
As shown in fig. 1, a first aspect of the present disclosure provides a process for producing propylene, the process comprising the steps of:
(a) carrying out MAPD (methyl acrylamide) hydrotreating on the propane raw material to obtain a hydrotreated material;
(b) carrying out weight removal treatment on the hydrotreated material to remove heavy components containing more than 4 carbon atoms so as to obtain a weight-removed material;
(c) carrying out PDH dehydrogenation treatment on the material subjected to the de-weighting treatment to obtain a material subjected to PDH dehydrogenation treatment;
(d) after removing hydrogen and ethane from the material subjected to PDH dehydrogenation treatment, carrying out rectification treatment to obtain distilled propylene and a second distillation residue material;
(e) returning the second raffinate stream to step (a) for the MAPD hydroprocessing with the propane feedstock.
Wherein MAPD hydrogenation refers to the hydrogenation of methylacetylene and propadiene in the propane raw material, and PDH dehydrogenation refers to the dehydrogenation of the propane raw material.
In accordance with the present disclosure, the MAPD hydrotreated propane stream may be divided into two streams, a propane feed stream and a second raffinate stream, wherein the propane feed stream is not limited in its contents to methylacetylene and propadiene. The second distillation residue material contains all the byproducts of methylacetylene and propadiene in the PDH dehydrogenation treatment, and the methylacetylene and the propadiene in the second distillation residue material and the methylacetylene and the propadiene in the raw material are removed in the PDH dehydrogenation treatment, so that the problem of coking of a dehydrogenation catalyst caused by the methylacetylene and the propadiene is avoided, and the operation stability of the device is improved; green oil generated in the MAPD hydrotreating process can be removed together with the heavy oil removal treatment, so that the influence of the green oil on the performance of the catalyst due to the fact that the green oil enters a PDH dehydrogenation treatment device along with material flow is avoided; meanwhile, the hydrogenated material flow contains almost no propylene, so even if the hydrogenated material flow is excessively hydrogenated, the loss of the target propylene product is not brought. The present disclosure reduces the quality requirements for the propane feedstock and eliminates the limitations on the content of methylacetylene and propadiene in the feed as compared to conventional processes for producing propylene. According to the present disclosure, the amount of methylacetylene in the propane feedstock may be in the range of 50 to 1000ppm mol, such as 50 to 100ppm mol, and the amount of propadiene may be in the range of 50 to 1000ppm mol, such as 50 to 100ppm mol.
In accordance with the present disclosure, the PDH dehydrogenated feed contains hydrogen and dehydrogenated C3The material can be sent into a cold separation device for gas-liquid separation after PDH dehydrogenation treatment so as to remove hydrogen. The cold separation device may be of a type conventional in the art, such as a cold box, fin heat exchanger.
For energy-matching utilization, cold-saving and energy-saving of the system, the stream in the system can be used as a cooling medium of the cold separation device, for example, in one embodiment of the disclosure, the method can comprise: the material after the weight removal treatment is used as a cooling medium to enter a cold separation device for heat exchange to obtain gaseous C3Material preparation; introducing gaseous C3Carrying out PDH dehydrogenation treatment on the material to obtain a material subjected to PDH dehydrogenation treatment; the material after PDH dehydrogenation enters a cold separation device, and gas-liquid separation is carried out through heat exchange condensation and throttling depressurization to obtain liquid C3Feed and crude hydrogen. The throttling depressurization refers to that the material is subjected to an isenthalpic throttling expansion process through a Joule-Thomson throttling expansion valve, so that the temperature of the material is further reduced, and the liquefaction process is facilitated; the cold separation device is preferably a cold box; gaseous C3The material can comprise one or more of ethane, propane, propylene, methylacetylene and propadiene; c in liquid state3The feed may comprise one or more of ethane, propane, propylene, methylacetylene and propadiene. In other embodiments of the present disclosure, the cold separation device may employ a conventional cooling medium such as an ethylene refrigerant, a propylene refrigerant.
Liquid C obtained after cold separation3The material contains a small amount of ethane, and liquid C can be obtained3Deethanizing the material in a deethanizer to obtain distilled C2The product and the first distillation residue material, the first distillation residue material contains the product propylene and a small amount ofThe propane, the methylacetylene and the propadiene can be separated by a propylene rectifying device to obtain propylene products with qualified purity; introducing the first distillation residue material into a propylene rectifying device for rectifying treatment to obtain distilled propylene and a second distillation residue material; wherein the material treated in the deethanizer is directly derived from the liquid C produced in the cold separation unit3The material and the cold separation treatment process can remove light components generated in the hydrogenation and dehydrogenation steps, and light components such as excessive hydrogen, methane and the like in MAPD hydrogenation products are prevented from entering a deethanizer, so that the load of the deethanizer is reduced, and the energy consumption of a device is reduced.
The present disclosure does not specifically require the operating conditions of the cold separation device, such as the pressure of the cold separation device, as long as liquid C is separated from the cold separation device3The pressure of the material can meet the conditions of the subsequent process. Other operating conditions of the cold separation unit, such as temperature, may also vary as required by the subsequent process flow. Meanwhile, in order to carry out cold quantity matching on the subsequent process, the heat exchange condensation in the cold separation device can be divided into primary condensation and/or fractional condensation.
Wherein, in order to improve the flexibility of the operation of the cold separation device, reduce the load of a condenser and a reboiler of the deethanizer and further reduce the energy consumption of the device, the liquid C separated from the cold separation device can be used3The material is divided into single feed and/or multiple feeds according to cold fractions at different temperatures and is introduced into the deethanizer, which corresponds to liquid C3The materials are firstly pre-separated before entering the deethanizer, thereby reducing the load of the device. Wherein, the temperature cold stage can be divided into 13 ℃, 12 ℃ and 35 ℃.
According to the present disclosure, the method may comprise: and carrying out crude hydrogen compression and pressure swing adsorption purification treatment on the crude hydrogen separated by the cold separation device to obtain purified hydrogen and tail gas, wherein the purity of the purified hydrogen is 99.0-99.999 volume percent, and the pressure is 1.5-2.5 MPa.
Further, in order to recycle hydrogen and improve the utilization rate of materials in the system, purified hydrogen can be used as raw material hydrogen for MAPD hydrotreatment;
further, the tail gas can be used as fuel gas for PDH dehydrogenation treatment to reduce the energy consumption of the system.
In order to save related equipment, reduce investment and equipment occupation, the pressure of the MAPD hydrotreating process can be selected according to the pressure of purified hydrogen obtained after pressure swing adsorption purification treatment, and the hydrogen distributed in the MAPD hydrotreating process does not need to be pressurized by a compressor. In accordance with the present disclosure, the pressure of the MAPD hydroprocessing reaction can vary over a wide range and can range from 1.8 to 3.0MPa, preferably from 2.0 to 2.5MPa, to ensure C at the reactor outlet of the MAPD hydroprocessing3The material is not vaporized; the reactor inlet temperature for MAPD hydroprocessing may be in the range of 30 to 50 c, preferably 35 to 45 c, to maximize the hydrogenation of methylacetylene and propadiene to propane.
In order to prevent the nitrogen oxides, heavy metals and water in the raw material from damaging equipment and influencing the reaction performance of the hydrogenation catalyst, the method can further comprise the following steps: the propane feedstock is subjected to feedstock pretreatment to remove nitrogen oxides, heavy metals and water from the propane feedstock prior to MAPD hydroprocessing.
According to the present disclosure, impurities may be generated in the PDH dehydrogenation process, the impurities include one or more of chloride, hydrogen sulfide and water, and in order to ensure the quality of the propylene product and to realize safe operation of the production process, the impurities need to be removed before introducing the impurities into a cold separation system, so that the PDH dehydrogenation treated material can be subjected to the hydrogen removal treatment after the reaction gas compression and the dehydrogenation impurity removal treatment.
In accordance with the present disclosure, the selectivity of the hydrogenation of the carbon trio hydrogenation catalyst to propylene may be left alone, with MAPD most preferably being fully hydrogenated to propane. So that excessive hydrogen distribution is allowed, and the overhead distillate of the heavy component removal tower can be fully condensed in principle. Preferably, by adopting the separation process of the invention, the reaction pressure of the carbon-three hydrogenation at least ensures that the carbon-three material at the outlet of the reactor is not vaporized; adjusting the inlet temperature of the reactor based on the generation of propane by MAPD through hydrogenation as much as possible; in order to ensure that the methylacetylene and the propadiene are hydrogenated to generate the propane to the maximum extent, the phenomenon that the catalyst is coked and the stability of the device is influenced due to the accumulation of the methylacetylene and the propadiene entering a reactor along with the circulating material flow is avoided, and the device can be used for preparing the catalyst by hydrogenation according to the hydrogenThe molar ratio of gas to alkyne, the hydrogen distribution for MAPD hydroprocessing may be in the range 1.3 to 2.5, for example 1.5 to 2.0, to ensure C overhead from the de-weighting device during de-weighting3The material can be fully condensed. Wherein, the hydrogen amount is the hydrogen amount added according to the MAPD alkyne content.
As shown in fig. 1, a second aspect of the present disclosure provides a system for producing propylene, the system comprising a propane feedstock inlet, a MAPD hydrogenation unit, a propane feedstock de-weighting unit, a PDH dehydrogenation unit, a cold separation unit, a deethanizer, a propylene rectification unit, and a propylene product outlet;
the propane raw material inlet, the MAPD hydrogenation device, the propane raw material de-weighting device and the PDH dehydrogenation device are sequentially connected, a dehydrogenation product outlet of the PDH dehydrogenation device is communicated with a material inlet of the cold separation device, a liquid product outlet of the cold separation device is communicated with a feed inlet of the deethanizer, a kettle liquid outlet of the deethanizer is communicated with a feed inlet of the propylene rectification device, a distillate outlet of the propylene rectification device is communicated with the propylene product outlet, and a raffinate outlet of the propylene rectification device is communicated with the propane raw material inlet.
In the system disclosed by the invention, the MAPD hydrogenation device is arranged behind the propane raw material inlet, so that the methyl acetylene and the propadiene in the fresh propane raw material can be completely removed at one time, the problem of catalyst coking in a PDH dehydrogenation device caused by the methyl acetylene and the propadiene in the propane raw material is avoided, the limitation on the contents of the methyl acetylene and the propadiene in the propane raw material is eliminated, and the operation stability of the device is improved; meanwhile, the green oil produced in the MAPD hydrogenation process can be separated in the heavy oil removal treatment process, so that the influence of the green oil on the performance of the dehydrogenation catalyst is avoided, and the separation difficulty is reduced.
The propane feedstock de-heavies apparatus, in accordance with the present disclosure, may be of a type conventional in the art, including, for example, a de-heavies column, a high pressure depropanizer, and a low pressure depropanizer, for removing components above C4 from the propane feedstock; the PDH dehydrogenation unit can be of a type conventional in the art, such as a butane dehydrogenation reactor; the propylene rectification apparatus may be of a type conventional in the art, for example, a rectification column; MAPD hydrogenation units may be of the type conventional in the art, such as acetylene hydrogenation reactors and carbon four hydrogenation reactors.
According to the present disclosure, the distillate outlet of the propane feedstock de-weighting device may be in communication with the cooling medium inlet of the cold separation device, and the cooling medium outlet of the cold separation device may be in communication with the feedstock gas inlet of the PDH dehydrogenation device. Wherein the distillate from the propane feed de-heaving plant may be used as a cooling medium in a cold separation plant, which may be conventional in the art, such as a cold box, gaseous C from a MAPD hydrogenation plant3The material and the cooling medium from the PDH dehydrogenation device are liquefied in the cold box through heat exchange, so that the reasonable utilization of the cold in the system is realized.
In order to realize the cyclic utilization of part of hydrogen in the system while separating to obtain a hydrogen product, the system can also comprise a crude hydrogen compression and pressure swing adsorption purification device, wherein a gas inlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with an uncondensed gas outlet of the cold separation device, a purified hydrogen outlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with a hydrogen inlet of the MAPD hydrogenation device, and a tail gas outlet of the crude hydrogen compression and pressure swing adsorption purification device is communicated with a fuel gas inlet of the PDH dehydrogenation device. Purified hydrogen obtained by the hydrogen compression and pressure swing adsorption purification device circularly enters the MAPD hydrogenation device to be reused, and generated tail gas is used as fuel gas and is introduced into the PDH dehydrogenation device.
In order to remove nitrogen oxides, heavy metals and water in the propane raw material and avoid the nitrogen oxides, the heavy metals and the water from entering a subsequent device along with the material flow to cause damage to the device and influence the operation of the system, the system can further comprise: and the raw material pretreatment device is arranged between the propane raw material inlet and the MAPD hydrogenation device.
According to the disclosure, the system may further include a reaction gas compression device and an impurity removal device connected in sequence, the reaction gas inlet of the reaction gas compression device is communicated with the dehydrogenation product outlet of the PDH dehydrogenation device, and the impurity removal device C3The material outlet is communicated with the material inlet of the cold separation device. Wherein, the reactor compression device comprises compressor units which are connected in sequence and compressThe unit will come from the gaseous C of PDH dehydrogenation unit3The material is pressurized to meet the pressure requirement of a subsequent impurity removal device; the impurity removal device removes impurities generated in the PDH dehydrogenation device, such as chloride, hydrogen sulfide and water, so that the quality of propylene products is ensured, and the adverse effects of the impurities on the operation stability of a system and the safety of a production process are avoided.
The present disclosure is further illustrated by the following examples, but is not to be construed as being limited thereby.
Example (b):
as shown in fig. 1, after performing denitrification, heavy metal removal, dehydration and drying pretreatment on a fresh propane raw material of 99.28 tons/hour, introducing the raw material into a MAPD hydrogenation device for MAPD hydrogenation treatment, so as to obtain a hydrotreated raw material, wherein the content of methylacetylene in the fresh propane raw material is 50ppm mol, the content of propadiene is 50ppm mol, and the hydrogen distribution amount of the MAPD hydrogenation treatment is 1.7. Then introducing the hydrotreated raw material into a de-weighting device for de-weighting treatment to remove four heavy components of carbon, introducing the de-weighted raw material into a cold separation device, and changing the raw material into gaseous C after heat exchange in the cold separation device3The material was subjected to PDH dehydrogenation. The dehydrogenated material is compressed, dechlorinated, dried and desulfurized and then enters a cold separation device, and crude hydrogen and liquid C are separated out in the cold separation device through heat exchange condensation and throttling depressurization processes3And (3) feeding. Wherein, the crude hydrogen separated in the cold separation device is subjected to crude hydrogen compression and pressure swing adsorption purification treatment to obtain purified hydrogen and tail gas. Wherein the purity of the purified hydrogen is 99.0-99.999 vol%, the pressure of the purified hydrogen is 2.30MPa, and the temperature is 40 ℃. Part of the purified hydrogen is directly used as raw material gas in the MAPD hydrotreating process, and additional pressurizing equipment is not needed for pressurizing treatment; the tail gas is introduced into a PDH dehydrogenation unit as fuel gas. Liquid C separated by cold separator3Condensing the material for 2-3 times according to the cold quantity matching requirement of the deethanizer, introducing 2-3 strands of feed materials into the deethanizer, and taking the light component separated from the top of the deethanizer as C2Delivering the product; c in the tower bottom of deethanizer3The components enter a propylene rectifying deviceAfter the rectification treatment of the propylene, a qualified propylene product with the purity of 99.6 mol% is obtained at the top of the propylene rectification device, and the distillation residue material at the bottom of the tower is converged with the fresh raw material propane and then circularly enters the MAPD hydrogenation device again for MAPD hydrogenation treatment.
The method and the system in the embodiment can simultaneously remove high-content methylacetylene and propadiene in fresh propane and by-products methylacetylene and propadiene in a PDH dehydrogenation treatment process, can remove green oil generated in an MAPD hydrotreating process in a de-weighting device, do not cause the problem of coking of a dehydrogenation catalyst, and have the advantages of stable operation of the device in a overhaul period, good catalyst activity and no need of regeneration.
The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.
It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.
Claims (10)
1. A process for producing propylene, comprising the steps of:
(a) carrying out MAPD (methyl acrylamide) hydrotreating on the propane raw material to obtain a hydrotreated material;
(b) carrying out weight removal treatment on the hydrotreated material to remove heavy components containing more than 4 carbon atoms so as to obtain a weight-removed material;
(c) carrying out PDH dehydrogenation treatment on the material subjected to the de-weighting treatment to obtain a material subjected to PDH dehydrogenation treatment;
(d) after removing hydrogen and ethane from the material subjected to PDH dehydrogenation treatment, carrying out rectification treatment to obtain distilled propylene and a second distillation residue material;
(e) returning the second raffinate stream to step (a) for the MAPD hydroprocessing with the propane feedstock.
2. The method of claim 1, wherein the method comprises: the material after the weight removal treatment is used as a cooling medium to enter a cold separation device for heat exchange to obtain gaseous C3Material preparation; introducing said gaseous C3Carrying out the PDH dehydrogenation treatment on the material to obtain the material subjected to the PDH dehydrogenation treatment; feeding the material subjected to PDH dehydrogenation treatment into the cold separation device, and performing gas-liquid separation through heat exchange condensation and throttling depressurization to obtain liquid C3A material and crude hydrogen;
mixing the liquid C3Deethanizing the material in a deethanizer to obtain distilled C2A product and a first raffinate; introducing the first distillation residue material into a propylene rectifying device for rectifying treatment to obtain the distilled propylene and the second distillation residue material;
wherein the heat exchange condensation in the cold separation device is primary condensation and/or fractional condensation; said liquid C3The feed of material to the deethanizer is a single feed and/or a multi-feed.
3. The method of claim 2, wherein the method comprises: carrying out crude hydrogen compression and pressure swing adsorption purification treatment on the crude hydrogen separated by the cold separation device to obtain purified hydrogen and tail gas, wherein the purity of the purified hydrogen is 99.0-99.999 volume percent, and the pressure is 1.5-2.5 MPa; the purified hydrogen was used as feed hydrogen for the MAPD hydroprocessing and the tail gas was used as fuel gas for the PDH dehydrogenation process.
4. The method according to claim 1 or 2, wherein the method comprises:
subjecting the propane feedstock to feedstock pretreatment to remove nitrogen oxides, heavy metals, and water from the propane feedstock prior to the MAPD hydroprocessing; and/or
And (3) carrying out reaction gas compression and dehydrogenation impurity removal treatment on the material subjected to PDH dehydrogenation treatment, and then carrying out hydrogen removal treatment.
5. The method according to claim 2, wherein the propane feedstock contains propane, methylacetylene and propadiene, the content of methylacetylene in the propane feedstock being 50-1000ppm mol and the content of propadiene being 50-1000ppm mol.
6. The method of claim 1, wherein the amount of hydrogen dosed in the MAPD hydroprocessing is in the range of 1.3 to 2.5.
7. The system for preparing the propylene is characterized by comprising a propane raw material inlet, a MAPD hydrogenation device, a propane raw material de-heavy device, a PDH dehydrogenation device, a cold separation device, a deethanizer, a propylene rectification device and a propylene product outlet;
the propane raw material inlet, the MAPD hydrogenation device, the propane raw material de-weighting device and the PDH dehydrogenation device are sequentially connected, a dehydrogenation product outlet of the PDH dehydrogenation device is communicated with a material inlet of the cold separation device, a liquid product outlet of the cold separation device is communicated with a feed inlet of the deethanizer, a kettle liquid outlet of the deethanizer is communicated with a feed inlet of the propylene rectification device, a distillate outlet of the propylene rectification device is communicated with the propylene product outlet, and a raffinate outlet of the propylene rectification device is communicated with the propane raw material inlet.
8. The system of claim 7, wherein a distillate outlet of the propane feedstock de-weighting device is in communication with a cooling medium inlet of the cold separation device, and a cooling medium outlet of the cold separation device is in communication with a feedstock gas inlet of the PDH dehydrogenation device.
9. The system of claim 7, further comprising a crude hydrogen compression and pressure swing adsorption purification unit, wherein a gas inlet of the crude hydrogen compression and pressure swing adsorption purification unit is in communication with the uncondensed gas outlet of the cold separation unit, a purified hydrogen outlet of the crude hydrogen compression and pressure swing adsorption purification unit is in communication with a hydrogen inlet of the MAPD hydrogenation unit, and a tail gas outlet of the crude hydrogen compression and pressure swing adsorption purification unit is in communication with a fuel gas inlet of the PDH dehydrogenation unit.
10. The system of claim 7, wherein the system further comprises:
a feedstock pretreatment unit disposed between the propane feedstock inlet and the MAPD hydrogenation unit; and/or
A reaction gas compression device and an impurity removal device which are connected in sequence, wherein a reaction gas inlet of the reaction gas compression device is communicated with a dehydrogenation product outlet of the PDH dehydrogenation device, and C of the impurity removal device3The material outlet is communicated with the material inlet of the cold separation device.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113721683A (en) * | 2020-05-25 | 2021-11-30 | 中国石油化工股份有限公司 | Automatic control method and equipment for carbon-three-liquid phase hydrogenation reactor |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4458096A (en) * | 1983-05-26 | 1984-07-03 | Air Products And Chemicals, Inc. | Process for the production of ethylene and propylene |
| CN103044180A (en) * | 2012-12-28 | 2013-04-17 | 北京石油化工学院 | Method for preparing isobutylene by dehydrogenizing iso-butane |
| CN103864556A (en) * | 2012-12-13 | 2014-06-18 | 中国科学院大连化学物理研究所 | Method for production of low carbon olefins from synthetic gas via low carbon alkanes |
| CN106187662A (en) * | 2016-08-02 | 2016-12-07 | 西南化工研究设计院有限公司 | A kind of fixed bed system of Trends In Preparation of Propene By Catalytic Dehydrogenation of Propane |
| CN207862226U (en) * | 2018-01-19 | 2018-09-14 | 山东大齐石油化工设计有限公司 | The device of preparing propylene by dehydrogenating propane |
-
2018
- 2018-09-21 CN CN201811117818.6A patent/CN110937975A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4458096A (en) * | 1983-05-26 | 1984-07-03 | Air Products And Chemicals, Inc. | Process for the production of ethylene and propylene |
| CN103864556A (en) * | 2012-12-13 | 2014-06-18 | 中国科学院大连化学物理研究所 | Method for production of low carbon olefins from synthetic gas via low carbon alkanes |
| CN103044180A (en) * | 2012-12-28 | 2013-04-17 | 北京石油化工学院 | Method for preparing isobutylene by dehydrogenizing iso-butane |
| CN106187662A (en) * | 2016-08-02 | 2016-12-07 | 西南化工研究设计院有限公司 | A kind of fixed bed system of Trends In Preparation of Propene By Catalytic Dehydrogenation of Propane |
| CN207862226U (en) * | 2018-01-19 | 2018-09-14 | 山东大齐石油化工设计有限公司 | The device of preparing propylene by dehydrogenating propane |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113721683A (en) * | 2020-05-25 | 2021-11-30 | 中国石油化工股份有限公司 | Automatic control method and equipment for carbon-three-liquid phase hydrogenation reactor |
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