阅读说明：本技术 合成气直接制烯烃的工艺方法 (Process for directly preparing olefin from synthetic gas ) 是由 苏俊杰 王仰东 刘苏 周海波 刘畅 焦文千 张琳 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种合成气直接制烯烃的工艺方法,包括：使合成气原料与催化剂接触,反应得到含有机烃、二氧化碳和未反应的合成气的物流；对所述含有机烃、二氧化碳和未反应的合成气的物流进行分离处理,依次分离出其中的二氧化碳和未反应的合成气；将分离出的二氧化碳和未反应的合成气循环回所述合成气原料中参与反应。在参与反应的气体中,以摩尔比计,H-2/(CO+CO-2)为(4：1)～(1：4),和/或CO/CO-2为(1-10)：1。方法利用催化剂的CO-2加氢活性原位转化一部分CO-2,一方面增加合成气中的碳利用率,一方面通过CO-2选择性的降低减少放热量。(The invention discloses a process method for directly preparing olefin from synthesis gas, which comprises the following steps: contacting a synthesis gas feed with a catalyst and reacting to obtain a stream comprising organic hydrocarbons, carbon dioxide and unreacted synthesis gas; separating the stream containing the organic hydrocarbon, the carbon dioxide and the unreacted synthesis gas to sequentially separate the carbon dioxide and the unreacted synthesis gas; recycling the separated carbon dioxide and unreacted synthesis gas back to the synthesis gas raw material to participate in the reaction. In the gas participating in the reaction, in terms of molar ratio, H 2 /(CO+CO 2 ) Is (4: 1) to (1: 4) and/or CO/CO 2 Is (1-10): 1. process for CO utilizing catalyst 2 Hydrogenation activity in-situ conversion of a portion of CO 2 On the one hand, the carbon utilization rate in the synthesis gas is increased, and on the other hand, the carbon utilization rate is increased through CO 2 The decrease in selectivity reduces the exotherm.)

1. A process for preparing olefin directly from synthesis gas comprises the following steps:

contacting a synthesis gas feed with a catalyst and reacting to obtain a stream comprising organic hydrocarbons, carbon dioxide and unreacted synthesis gas;

separating the stream containing the organic hydrocarbon, the carbon dioxide and the unreacted synthesis gas to sequentially separate the carbon dioxide and the unreacted synthesis gas;

recycling the separated carbon dioxide and unreacted synthesis gas back to the synthesis gas raw material to participate in the reaction.

2. The process of claim 1 wherein H is present in the gas involved in the reaction in terms of mole ratios₂/(CO+CO₂) Is (4: 1) to (1: 4) and/or CO/CO₂Is (1-10): 1.

3. a process according to claim 1 or 2, wherein the catalyst comprises an oxide and a molecular sieve.

4. A process according to any one of claims 1 to 3, wherein the weight ratio of the oxides to the molecular sieve is from (1: 6) to (6: 1); preferably (1: 4) to (4: 1).

5. The process of any one of claims 1 to 4, wherein the oxide is CO and CO₂The conversion-active oxide preferably includes at least one of oxides of Zn, Cr, In, Zr, Al, Ga, and composite oxides thereof.

6. The process of any one of claims 1 to 5, wherein the molecular sieve is selected from AlPO and SAPO molecular sieves; preferably includes at least one of AlPO-18, AlPO-17, AlPO-34, AlPO-14, AlPO-11, AlPO-5, SAPO-18, SAPO-17, SAPO-11, and SAPO-5.

7. The process as claimed in any one of claims 1 to 6, wherein the reaction temperature is 340-460 ℃; and/or the reaction pressure is 0.5-8 MPa; and/or the volume space velocity is 800-^-1。

8. A process according to any one of claims 1 to 7, wherein the stream comprising organic hydrocarbons, carbon dioxide and unreacted synthesis gas is subjected to sequential decarbonisation and hydrocarbon separation processes, in which carbon dioxide and unreacted synthesis gas are separated sequentially.

9. An apparatus for direct synthesis of olefins from syngas, comprising:

a reactor, which is used for enabling the synthesis gas raw material to contact with a catalyst to react to obtain a material flow containing organic hydrocarbon, carbon dioxide and unreacted synthesis gas;

a decarbonization apparatus coupled to the reactor for receiving a stream containing organic hydrocarbons, carbon dioxide, and unreacted syngas from the reactor and separating carbon dioxide therefrom;

hydrocarbon separation means connected to said decarbonization means to receive a stream containing organic hydrocarbons and unreacted synthesis gas from said decarbonization means and to separate the unreacted synthesis gas therein;

a premixer coupled to the reactor for receiving fresh syngas, recycled carbon dioxide and unreacted syngas and delivering a mixture thereof to the reactor.

10. The apparatus of claim 9, further comprising:

and the first heat exchanger is respectively connected with the outlet of the reactor and the inlet of the decarburization device.

11. The apparatus of claim 9 or 10, further comprising:

and the second heat exchanger is respectively connected with the outlet of the first heat exchanger and the inlet of the decarburization device.

Technical Field

The invention relates to a process method for directly preparing olefin from synthesis gas, belonging to the technical field of chemical engineering.

Background

The energy characteristics of China are 'rich coal, lack of oil and little gas'. The dependence of petroleum consumption on the outside is high, the economic development is severely restricted, and clean and efficient utilization of coal, natural gas, biomass and the like is always an important issue of sustainable development. In principle, coal, natural gas and biomass are directly converted into chemicals with a poor industrialization prospect, so that the selection of a proper conversion medium as a platform for coal chemical industry and natural gas chemical industry to realize chemical synthesis is particularly necessary. In recent years, with the increasing maturity of coal gasification, natural gas reforming, and biomass gasification technologies, syngas chemistry has been considered the most feasible alternative to petroleum-based production of oil and bulk chemicals.

The low-carbon olefin, which is C2-C4 olefin, is a very important chemical raw material. Ethylene production is a measure of the state of the chemical industry. At present, the outstanding problems in the production of ethylene and propylene in China are low consumption self-sufficiency and outstanding supply-demand contradiction. The conventional process for producing ethylene mainly by steam cracking technology is completely dependent on and consumes a large amount of non-renewable petroleum resources. The development of the low-carbon hydrocarbon synthesis technology of a non-petroleum route can not only supplement the existing production technology, but also provide reference for the utilization of new energy in the future.

At present, the research on the technology of preparing low carbon hydrocarbon from synthesis gas is still in the research and development stage of the laboratory, mainly focuses on the research and development of catalysts, and the research on the process is relatively deficient. The catalyst is mainly divided into two systems, one is a modified catalyst based on a Fischer-Tropsch synthesis catalyst, and the other is a supported catalyst mainly taking iron and cobalt as active centers, the catalyst generally has high CO conversion rate, the hydrocarbon product distribution generally meets the ASF carbon number distribution rule, and the selectivity of the C2-C4 hydrocarbon product is difficult to break through 60%. Another concept is to use a dual function coupled catalyst process. I.e., coupling the oxide and the molecular sieve. science (2016) has published that ZnCrOx in combination with MSAPO molecular sieves achieves C2-C4 hydrocarbon selectivity over 90% (excluding CO 2). German Korea (2016) also discloses a technological process using ZnZr oxide and SAPO34 combined catalyst, and its C2-C4 hydrocarbon selectivity also can be up to above 90% (excluding CO)₂). German Korea (2016) also discloses a technological process using ZnZr oxide and SAPO34 combined catalyst, and its C2-C4 hydrocarbon selectivity also can be up to above 90% (excluding CO)₂). The most important characteristic of the process is CO₂High selectivity (more than 45% of total product), and high CO content₂Also, the exothermic amount of the reaction system is drastically increased. How to reduce CO in the reaction system₂Generation, improving the utilization of carbon is an urgent problem to be solved.

Disclosure of Invention

The invention aims to solve the problem of CO in the prior art₂High selectivity and great carbon loss in synthetic gas, and provides one new kind of technological process of preparing olefin with synthetic gas, and the process utilizes CO in catalyst₂Hydrogenation activity in-situ conversion of a portion of CO₂On the one hand, the carbon utilization rate in the synthesis gas is increased, and on the other hand, the carbon utilization rate is increased through CO₂The decrease in selectivity reduces the exotherm.

According to one aspect of the present invention, there is provided a process for the direct production of olefins from synthesis gas, comprising:

contacting a synthesis gas feed with a catalyst and reacting to obtain a stream comprising organic hydrocarbons, carbon dioxide and unreacted synthesis gas;

separating the stream containing the organic hydrocarbon, the carbon dioxide and the unreacted synthesis gas to sequentially separate the carbon dioxide and the unreacted synthesis gas;

recycling the separated carbon dioxide and unreacted synthesis gas back to the synthesis gas raw material to participate in the reaction.

According to some embodiments of the invention, in the gas participating in the reaction, H is present in molar ratio₂/(CO+CO₂) Is (4: 1) to (1: 4) and/or CO/CO₂Is (1-10): 1.

according to a preferred embodiment of the invention, H is present in the gas participating in the reaction in molar ratio₂/(CO+CO₂) Is (2: 1) to (1: 2) and/or CO/CO₂Is (2-5): 1.

according to a preferred embodiment of the invention, the catalyst comprises an oxide and a molecular sieve.

According to a preferred embodiment of the invention, the weight ratio of said oxides to molecular sieve is (1: 6) to (6: 1); preferably (1: 4) to (4: 1).

According to a preferred embodiment of the invention, the oxide is of CO and CO₂The conversion-active oxide preferably includes at least one of oxides of Zn, Cr, In, Zr, Al, Ga, and composite oxides thereof.

According to a preferred embodiment of the invention, the molecular sieve is selected from AlPO and SAPO molecular sieves; preferably includes at least one of AlPO-18, AlPO-17, AlPO-34, AlPO-14, AlPO-11, AlPO-5, SAPO-18, SAPO-17, SAPO-11, and SAPO-5.

According to a preferred embodiment of the present invention, the reaction temperature is 340-460 ℃; and/or the reaction pressure is 0.5-8 MPa; and/or the volume space velocity is 800-^-1。

According to a preferred embodiment of the invention, the stream comprising organic hydrocarbons, carbon dioxide and unreacted synthesis gas is subjected to a decarbonation treatment and a hydrocarbon separation treatment in succession, in which carbon dioxide and unreacted synthesis gas are separated in succession.

According to a preferred embodiment of the present invention, the decarburization treatment includes at least one of an adsorption decarburization treatment, a solvent decarburization treatment, and a film decarburization treatment.

According to a preferred embodiment of the present invention, the hydrocarbon separation process comprises at least one of a pressure swing adsorption process, a cryogenic separation process, and an oil absorption separation process.

According to a preferred embodiment of the invention, the synthesis gas comprises hydrogen and carbon monoxide in a molar ratio of 0.5 to 3.

According to a preferred embodiment of the invention, the reaction yields a mixture containing organic hydrocarbons, CO₂And the material flow of the unreacted synthesis gas exchanges heat with fresh synthesis gas and then is subjected to decarburization treatment, and optionally, organic hydrocarbon and CO are obtained by reaction₂And the gas flow of the unreacted synthesis gas exchanges heat with the fresh synthesis gas firstly, and then exchanges heat with the separated carbon dioxide again.

According to another aspect of the present invention, there is provided an apparatus for direct synthesis gas to olefins, comprising:

a reactor, which is used for enabling the synthesis gas raw material to contact with a catalyst to react to obtain a material flow containing organic hydrocarbon, carbon dioxide and unreacted synthesis gas;

a decarbonization apparatus coupled to the reactor for receiving a stream containing organic hydrocarbons, carbon dioxide, and unreacted syngas from the reactor and separating carbon dioxide therefrom;

hydrocarbon separation means connected to said decarbonization means to receive a stream containing organic hydrocarbons and unreacted synthesis gas from said decarbonization means and to separate the unreacted synthesis gas therein;

a premixer coupled to the reactor for receiving fresh syngas, recycled carbon dioxide and unreacted syngas and delivering a mixture thereof to the reactor.

According to a preferred embodiment of the invention, the device further comprises:

and the first heat exchanger is respectively connected with the outlet of the reactor and the inlet of the decarburization device.

The first heat exchanger is provided with a material flow inlet, a material flow outlet, a synthesis gas inlet and a synthesis gas outlet, and a material flow channel and a synthesis gas channel are arranged in the first heat exchanger; wherein the material flow inlet and the material flow outlet are the inlet and the outlet of the material flow channel; the syngas inlet and the syngas outlet are inlets and outlets of the syngas channel.

According to a preferred embodiment of the invention, the stream inlet is connected to the reactor outlet and the stream outlet is connected to the inlet of the decarbonation device. The synthesis gas inlet is connected with a fresh synthesis gas storage device, and the synthesis gas outlet is connected with the premixer.

According to a preferred embodiment of the invention, the device further comprises:

and the second heat exchanger is respectively connected with the outlet of the first heat exchanger and the inlet of the decarburization device.

The second heat exchanger is provided with a material flow inlet, a material flow outlet, a carbon dioxide inlet and a carbon dioxide outlet, and a material flow channel and a carbon dioxide channel are arranged in the second heat exchanger; wherein the material flow inlet and the material flow outlet are the inlet and the outlet of the material flow channel; the carbon dioxide inlet and the carbon dioxide outlet are the inlet and the outlet of the carbon dioxide channel.

According to a preferred embodiment of the invention, the stream inlet is connected to the stream outlet of the first heat exchanger and the stream outlet is connected to the inlet of the decarbonation device. The carbon dioxide inlet is connected with the gas outlet of the decarburization device, and the carbon dioxide outlet is connected with the premixer.

According to a preferred embodiment of the invention, the reactor is a fixed bed reactor, preferably a tubular fixed bed reactor.

According to a preferred embodiment of the present invention, the decarbonizing means is at least one selected from the group consisting of an adsorption decarbonizing means, a solvent absorption decarbonizing means, and a membrane separation decarbonizing means.

According to a preferred embodiment of the present invention, the hydrocarbon separation unit is selected from at least one of a pressure swing adsorption unit, a cryogenic separation unit, an oil absorption separation unit.

In the present invention, CO₂Selectivity means CO formed by the reaction₂The amount divided by the molar percentage of the amount of CO conversion.

Organic hydrocarbon selectivity refers to the molar percentage of carbon containing number of all organic hydrocarbon products divided by the amount of CO conversion.

C2-C4 olefin selectivity refers to the mole percent of carbon containing numbers of C2-C4 olefin products to the carbon containing numbers of all organic hydrocarbon products.

Compared with the prior technical scheme for preparing olefin by converting synthesis gas by adopting a fixed bed, the technology provides CO₂Cyclic process scheme for in-situ conversion of a portion of CO using a catalyst₂Can greatly reduce CO while ensuring high selectivity of low-carbon hydrocarbon₂The selectivity of the synthesis gas is improved, the utilization rate of carbon in the synthesis gas is improved, and the heat release is reduced, so that the method is suitable for industrial production.

Drawings

FIG. 1 shows a schematic of an apparatus and process flow for direct synthesis gas to olefins according to one embodiment of the present invention;

FIG. 2 shows a schematic diagram of an apparatus and process for direct synthesis of olefins from syngas according to another embodiment of the present invention.

Description of reference numerals: 1 is a fresh synthesis gas inlet; 2 is a premixer; 3 is a tubular fixed bed reactor; 4 is a decarbonization device; 5 is CO₂A discharge port; 6 is a hydrocarbon separation unit; 7 is a relief port; 8; an organic hydrocarbon product outlet; 9 is a first heat exchanger; and 10 is a second heat exchanger.

Detailed Description

The present invention will be further illustrated by the following examples, but is not limited to these examples.

Fig. 1 shows an apparatus for direct production of olefins from syngas according to an embodiment of the present invention, which includes a premixer 2, a reactor 3, a decarbonizer 4, and a hydrocarbon separator 6. The technological process for directly preparing olefin by using the synthesis gas of the device comprises the following steps: preheating fresh synthesis gas 1 through a premixer, then entering a reactor 3 to contact and react with a catalyst to generate a material flow containing organic hydrocarbon, carbon dioxide and unreacted synthesis gas; the material flow enters a decarbonization device 4, carbon dioxide is removed, a material flow containing organic hydrocarbon and unreacted synthesis gas is obtained, one part of the carbon dioxide is discharged through a carbon dioxide discharge port 5, and the other part of the carbon dioxide is recycled to the premixer 2 to be mixed with fresh synthesis gas; the material flow containing organic hydrocarbon and unreacted synthesis gas enters a hydrocarbon separation device 6, organic hydrocarbon and unreacted synthesis gas are obtained through separation, wherein the organic hydrocarbon is discharged through an organic hydrocarbon product outlet, most of the unreacted synthesis gas is circulated back to the premixer 2 to be mixed with fresh synthesis gas, and the small part of the unreacted synthesis gas is discharged through a purge outlet 7.

Fig. 2 shows an apparatus for directly producing olefins from syngas according to an embodiment of the present invention, which includes a premixer 2, a reactor 3, a decarbonizer 4, a hydrocarbon separator 6, a first heat exchanger 9, and a second heat exchanger 10. The technological process for directly preparing olefin by using the synthesis gas of the device comprises the following steps: preheating fresh synthesis gas 1 through a first heat exchanger 9 and a premixer, and then entering a reactor 3 to contact and react with a catalyst to generate a material flow containing organic hydrocarbon, carbon dioxide and unreacted synthesis gas; the material flow enters a first heat exchanger 9, exchanges heat with fresh synthesis gas, then enters a second heat exchanger 10, exchanges heat with carbon dioxide separated by the decarburization device, enters a decarburization device 4, removes the carbon dioxide therein to obtain a material flow containing organic hydrocarbon and unreacted synthesis gas, one part of the carbon dioxide is discharged through a carbon dioxide discharge port 5, the other part of the carbon dioxide enters the second heat exchanger 10, exchanges heat with the material flow containing organic hydrocarbon, carbon dioxide and unreacted synthesis gas, and then the material flow is circulated back to the premixer 2 to be mixed with the fresh synthesis gas; the material flow containing organic hydrocarbon and unreacted synthesis gas enters a hydrocarbon separation device 6, organic hydrocarbon and unreacted synthesis gas are obtained through separation, wherein the organic hydrocarbon is discharged through an organic hydrocarbon product outlet, most of the unreacted synthesis gas is circulated back to the premixer 2 to be mixed with fresh synthesis gas, and the small part of the unreacted synthesis gas is discharged through a purge outlet 7.

[ example 1 ]

The process flow shown in figure 1 is adopted, the catalyst in the fixed bed is filled by oxide and molecular sieve 1:1, the ZnCr oxide accounts for 90 percent in the oxide, and the InZr oxideAccounting for 10 percent; the molecular sieve is SAPO-34 molecular sieve, and is prepared at 400 deg.C under 4.0Mpa for 4800h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

[ example 2 ]

The same process flow and catalyst loading as in example 1 was used; at 400 deg.C, 4.0Mpa, 4800h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 8:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

[ example 3 ]

The process flow of the example 1 is adopted, the catalyst in the fixed bed is filled by 1:1 of oxide and molecular sieve, and the ZnCr oxide accounts for 90 percent and the InZr oxide accounts for 10 percent in the oxide; the molecular sieve is SAPO-34 molecular sieve, and is prepared at 400 deg.C under 4.0Mpa for 4800h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 4:4:0.5, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

[ example 4 ]

The process flow of the example 1 is adopted, the catalyst in the fixed bed is filled with oxides and molecular sieves in a ratio of 1:1, and the oxides are ZnCr oxides; the molecular sieve is SAPO-34 molecular sieve, and is prepared at 400 deg.C under 4.0Mpa for 4800h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

[ example 5 ]

The process flow shown in figure 2 is adopted, the catalyst in the fixed bed is filled by oxides and molecular sieves in a ratio of 1:1, the ZnCr oxide in the oxides accounts for 90 percent, and the InZr oxide accounts for 10 percent; the molecular sieve is SAPO-18 molecular sieve, and is prepared at 400 deg.C under 4.0Mpa for 4800h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

[ example 6 ]

The process flow shown in figure 2 is adopted, and the catalyst is prepared in a fixed bedThe filling of the chemical agent adopts 1:1 filling of oxide and molecular sieve, wherein ZnCr oxide accounts for 90% and InZr oxide accounts for 10% in the oxide; the molecular sieve is SAPO-18 molecular sieve, and is prepared at 400 deg.C under 5.0Mpa for 6000h^-1Under the conditions of (1), control of H₂:CO:CO₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

Comparative example 1

The fixed bed direct reaction mode (no carbon dioxide recycle) was used, the catalyst loading was the same as in example 1; at 400 deg.C, 4.0Mpa, 4800h^-1Under the conditions of (1), control of H₂:CO:N₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

Comparative example 2

The fixed bed direct reaction mode (no carbon dioxide recycle) was used with the same catalyst loading as in example 4; at 400 deg.C, 4.0Mpa, 4800h^-1Under the conditions of (1), control of H₂:CO:N₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

Comparative example 3

The fixed bed direct reaction mode (no carbon dioxide recycle) was used with the same catalyst loading as in example 5; at 400 deg.C, 4.0Mpa, 4800h^-1Under the conditions of (1), control of H₂:CO:N₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

Comparative example 4

The fixed bed direct reaction mode (no carbon dioxide recycle) was used with the same catalyst loading as in example 6; at 400 deg.C, 5.0Mpa, 6000h^-1Under the conditions of (1), control of H₂:CO:N₂The reaction was carried out for 20 hours at 4:4:1, the reaction product was monitored on-line by gas chromatography, and the results are shown in table 1.

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.