CN111116297A - Separation device and method for preparing olefin from synthesis gas - Google Patents

Separation device and method for preparing olefin from synthesis gas Download PDF

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CN111116297A
CN111116297A CN201811275352.2A CN201811275352A CN111116297A CN 111116297 A CN111116297 A CN 111116297A CN 201811275352 A CN201811275352 A CN 201811275352A CN 111116297 A CN111116297 A CN 111116297A
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separation
synthesis gas
stream
carbon
zone
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胡帅
杨卫胜
胡松
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00Purification; Separation; Use of additives
    • C07C7/11Purification; Separation; Use of additives by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00Purification; Separation; Use of additives
    • C07C7/005Processes comprising at least two steps in series
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00Purification; Separation; Use of additives
    • C07C7/04Purification; Separation; Use of additives by distillation
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00Purification; Separation; Use of additives
    • C07C7/12Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers

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Abstract

The invention relates to a separation device and a separation method for preparing olefin from synthesis gas, which mainly solve the problems that the subsequent separation process is influenced by a large amount of unconverted synthesis gas contained in product gas due to low conversion rate in the reaction process of preparing olefin from synthesis gas, and the efficiency of equipment for removing carbon dioxide, carbon monoxide and hydrogen is low in the existing cryogenic separation technology. The separation device comprises: 1) a carbon-three-carbon-four separation zone; configured to receive the product gas stream and discharge a light hydrocarbon stream and a heavy hydrocarbon stream; 2) a decarbonization zone; configured to receive the light hydrocarbon stream, to emit a carbon dioxide stream and a decarbonated stream; 3) a dehydrogenation zone; the technical scheme that the decarbonization material flow is received and the recycle material flow and the mixed hydrocarbon material flow are discharged better solves the problems, can be used for the separation process of preparing olefin products from synthesis gas, and has the advantages of high equipment efficiency, high product recovery rate, high product purity and low energy consumption in the separation process.

Description

Separation device and method for preparing olefin from synthesis gas
Technical Field
The invention relates to a separation device and a separation method for preparing olefin from synthesis gas, in particular to a separation device and a separation method for preparing olefin from synthesis gas by a one-step method.
Technical Field
Olefins, particularly ethylene, propylene and butylene, are important basic chemical raw materials, and the demand for them has been increasing in recent years. Generally, olefins are derived primarily from petroleum processing. With the increasing scarcity of petroleum resources, the cost of producing ethylene and propylene from petroleum resources is increasing, and the development of the technology for producing olefin from non-petroleum resources such as coal or natural gas and the like attracts more and more attention at home and abroad. The method for preparing low-carbon olefin by using coal, natural gas and the like as raw materials generally comprises the steps of converting the coal and the natural gas into synthesis gas and then preparing the low-carbon olefin from the synthesis gas. In the long run, the method has important strategic significance on the adjustment of energy structures in China and the reduction of dependence on petroleum resources.
The current mature technical route for preparing olefin from coal comprises four core technologies of coal gasification, synthesis gas purification, methanol synthesis and preparing olefin from methanol. Firstly, gasifying coal to prepare synthesis gas, then transforming the synthesis gas, purifying the transformed synthesis gas, finally preparing the purified synthesis gas into crude methanol and rectifying to finally produce qualified methanol. The main problems of coal-to-olefin are as follows: long technical route, large equipment quantity, large equipment investment, large raw material and energy consumption and high water consumption.
The direct preparation of olefin from synthesis gas avoids the synthesis and purification procedures of intermediate products, has shorter process route and reduces investment cost and operation cost. However, the process for directly preparing olefin from synthesis gas has not yet realized industrialized operation, and the main research is still focused on the development of the catalyst, but the research on the aspects of the development of the process flow, the design of the product separation scheme and the like is very deficient.
From the patent and literature methods, the direct preparation of olefins from synthesis gas is a Fischer-Tropsch (F-T) synthesis process, the product is distributed in a wide carbon number range, the product gas at the reaction outlet contains a large amount of unconverted synthesis gas, and the selectivity of low-carbon olefins is low, so that the separation difficulty is increased, and the improvement of economic benefit is greatly influenced.
CN 102666441 a discloses a supported iron-based catalyst for use in the production of lower olefins from synthesis gas by a process for producing lower olefins from a feed stream comprising carbon monoxide and hydrogen, for example by the Fischer-Tropsch (Fischer-Tropsch) process, at a temperature above 270 ℃ and not above 500 ℃, the iron-containing particles of the catalyst composition having an average particle size below 20m, preferably below 10 nm.
CN 102971277A discloses the production of light olefins such as C from synthesis gas using an iron based catalyst, the step of contacting the synthesis gas with the iron based catalyst at a temperature in the range of 250 to 350 ℃ and a pressure in the range of 10 to 40 bar (bar)2~4A process for producing olefins. H of synthesis gas2: the molar ratio of CO is in the range of 1.5 to 2.5.
CN 103664447A discloses a catalyst composition for preparing olefin from synthesis gas, which comprises CO and H with a molar ratio of 0.8-2.22The mixed gas is used as a raw material, and the reaction temperature is 250-350 ℃, the reaction pressure is 0.5-2.5 MPa, and the volume space velocity is 1000-4000 hours-1Under the condition of (1), the catalyst is in contact reaction with a catalyst to generate olefin, wherein the catalyst comprises the following components, by weight, 1-20 parts of a shell selected from one of ZSM-5 or β zeolite and 80-99 parts of an inner core.
CN108017481 discloses a separation method of a product gas for directly preparing low-carbon olefin from synthesis gas, which comprises the steps of cooling and drying the product gas of a reaction for directly preparing olefin from synthesis gas, and then feeding the cooled and dried product gas into a product gas purification unit to remove a carbon dioxide component in the product gas, so as to obtain a purified product gas; the purified product gas enters a synthesis gas primary recovery unit, and primary recovery is carried out on unconverted synthesis gas in the synthesis gas primary recovery unit; the product gas after primary recovery enters a synthesis gas secondary recovery unit for secondary recovery; the tower bottom material after secondary recovery enters a carbon dioxide and carbon three and heavy component separation unit to separate a carbon dioxide component from the carbon three and the heavy component; feeding the materials at the top of the tower of the carbon two and carbon three and heavy component separation unit into an ethylene rectification unit to obtain an ethylene product; the tower bottom material enters a carbon three and heavy component separation unit to separate carbon three components from carbon four and heavy components; and the tower top material of the carbon three and heavy component separation unit enters a propylene rectification unit to obtain a propylene product, and the tower bottom material enters a debutaning unit to obtain a carbon four product and a gasoline product. The method sends all the product gas into the carbon dioxide removing area, the dehydrogenation gas area and the carbon monoxide removing area, reduces the efficiency of the separation equipment, and increases the size and the investment of the equipment. In addition, after the high-temperature product gas is cooled, the high-temperature product gas is sent to a carbon dioxide removal area, a dehydrogenation gas area and a carbon monoxide removal area, and then the high-temperature product gas is sequentially separated, so that the energy loss is large.
In summary, in order to accelerate the industrialization process of directly preparing olefin from syngas, it is very necessary to provide a separation method with convenient operation and simple process, which can smoothly complete the separation of each component in the product gas at the outlet of the reaction for directly preparing olefin from syngas. Meanwhile, the composition distribution characteristics of each component in the product gas are considered, and a proper separation technology is selected to ensure the quality of the low-carbon olefin product.
The invention provides a separation method for preparing olefin from synthesis gas, which aims to solve the problems in a targeted manner.
Disclosure of Invention
The invention relates to a separation device and a separation method for preparing olefin from synthesis gas, which mainly solve the problems that the subsequent separation process is influenced by a large amount of unconverted synthesis gas contained in product gas due to low conversion rate in the reaction process of preparing olefin from synthesis gas and the efficiency of equipment for removing carbon dioxide, carbon monoxide and hydrogen in the existing cryogenic separation technology is low, can be used for the separation process of preparing olefin products from synthesis gas, and has the advantages of high equipment efficiency, high product recovery rate, high product purity and low energy consumption in the separation process.
In order to solve the above problems, the present invention provides a separation apparatus for producing olefins from synthesis gas, comprising:
1) a carbon-three-carbon-four separation zone; configured to receive the product gas stream and discharge a light hydrocarbon stream and a heavy hydrocarbon stream;
2) a decarbonization zone; configured to receive the light hydrocarbon stream, to emit a carbon dioxide stream and a decarbonated stream;
3) a dehydrogenation zone; configured to receive the decarbonated stream and discharge a recycle stream and a mixed hydrocarbon stream.
In the technical scheme of the invention, the separation device also comprises a sequential separation area; configured to receive the mixed hydrocarbon stream and discharge an olefin product.
In the technical scheme of the invention, a heat exchange area is also arranged between the dehydrogenation area and the sequential separation area.
In the technical scheme of the invention, the separation area of the carbon-three-carbon-four separation area comprises a depropanizer.
In the technical scheme of the invention, the decarbonization zone comprises an absorption tower and a resolving tower.
In the technical scheme of the invention, the dehydrogenation zone comprises one or at least one of a pressure swing adsorption device, a temperature swing adsorption device and a membrane separation device.
In the technical scheme of the invention, the heat exchange area comprises a heat exchanger; it is preferable to use a heat exchanger containing ethylene as a refrigerant.
In the technical scheme of the invention, the sequential separation zone comprises a demethanizer, a deethanizer, an ethylene rectifying tower and a propylene rectifying tower.
In the technical scheme of the invention, the separation device also comprises a debutanizer.
The invention also provides a separation method by using the separation device, which comprises the following steps:
a) separating the product gas stream by a carbon-three-carbon-four separation zone to obtain a light hydrocarbon stream containing three or less carbon components and a heavy hydrocarbon stream containing four or more carbon components;
b) separating the light hydrocarbon material flow into a carbon dioxide material flow mainly containing carbon dioxide components and a decarbonization material flow through a decarbonization area;
c) the decarbonated stream is separated in a dehydrogenation zone into a recycle stream comprising primarily carbon monoxide and hydrogen and a mixed hydrocarbon stream.
In the technical scheme, the mixed hydrocarbon material flow is cooled in a heat exchange area to obtain a low-temperature mixed hydrocarbon material flow; optionally, the low-temperature mixed hydrocarbon stream is sent to a sequential separation zone for further separation to obtain an olefin product.
In the above technical scheme, at least part of the product gas stream comes from a synthesis gas olefin preparation reactor; optionally, at least part of the recycle stream obtained in step c) is returned to the synthesis gas to olefins reactor.
In the technical scheme, the carbon dioxide is separated from the decarbonization zone by an absorption and desorption method.
In the above technical scheme, the decarbonization zone generates bicarbonate ions.
In the above technical scheme, the dehydrogenation zone adopts one or at least one of a PSA separation method and a membrane separation method to separate carbon monoxide or/and hydrogen.
In the technical scheme, the temperature of the low-temperature mixed hydrocarbon material flow is lower than or equal to minus 100 ℃; preferably 105 ℃ or lower.
In the technical scheme, the pressure of the low-temperature mixed hydrocarbon material flow is more than or equal to 3.0 MPaG; preferably 3.1MPaG or more.
In the technical scheme, the heavy hydrocarbon material flow obtained in the step a) is separated by a debutanizer to obtain a carbon-containing four-component carbon-four material flow and a carbon-containing five-component and above C5+ material flow.
In the above technical solution, the product gas stream comprises carbon dioxide, carbon monoxide, hydrogen and mixed hydrocarbons.
In the above technical solution, preferably, the product gas stream comprises, by weight, 10% to 40% of carbon dioxide, 1% to 5% of hydrogen, 30% to 70% of carbon monoxide, and 10% to 40% of mixed hydrocarbons.
In the above technical solution, preferably, the product gas stream contains 15% to 35% of carbon dioxide by weight percentage.
In the above technical solution, it is preferable that the mixed hydrocarbon stream contains at least 60% by weight of C2-C4 hydrocarbons.
In the above technical solution, it is more preferable that the mixed hydrocarbon stream contains at least 70% by weight of C2-C4 hydrocarbons.
In the above technical solution, it is most preferable that the mixed hydrocarbon stream contains at least 75% by weight of C2-C4 hydrocarbons.
In a technical solution of the present invention, at least 75% of the recycle stream is returned to the synthesis gas to olefins reactor.
In the technical scheme of the invention, preferably, at least 95% of the circulating stream is returned to the synthesis gas olefin preparation reactor.
In the technical scheme of the invention, more preferably, all the recycle stream is returned to the synthesis gas olefin preparation reactor.
In another technical scheme of the invention, the heavy hydrocarbon material flow is separated by a dehexanizer to obtain a mixed C-C four material flow containing C four-C six components and a C-C seven material flow containing C seven or more components, the mixed C-four material flow can be sent to an olefin cracking device to crack olefin components into a crude propylene material flow mainly containing ethylene and propylene, and the crude propylene material flow is sent to a depropanizer as a feed.
In the technical scheme of the invention, the decarbonized material flow mainly contains carbon monoxide, hydrogen, methane, ethylene, ethane, propylene and propane.
In the technical scheme of the invention, the mixed hydrocarbon stream mainly contains methane, ethylene, ethane, propylene and propane.
According to the technical scheme, when the carbon dioxide absorbent in the decarbonization region adopts potassium carbonate and sodium carbonate of the same series as the potassium carbonate as the absorbent, carbon dioxide is firstly hydrolyzed to generate hydrogen ions and bicarbonate ions, the hydrogen ions and the carbonate ions react to generate the bicarbonate ions, namely, carbon dioxide, water and carbonate react to generate bicarbonate, so that the effect of absorbing the carbon dioxide is achieved.
In another technical scheme of the invention, when the carbon dioxide absorbent in the decarbonization region adopts methyldiethanolamine and the ethanolamine, diethanolamine and diisopropanolamine which are the same series as the methyldiethanolamine as the absorbent, carbon dioxide is firstly hydrolyzed to generate hydrogen ions and bicarbonate ions, the hydrogen ions react with alcohol amine substances to generate protonated alcohol amine, namely, the carbon dioxide, water and the alcohol amine react to generate the bicarbonate ions and the protonated alcohol amine, so that the effect of absorbing the carbon dioxide is achieved.
The inventor considers that the energy is saved when the methyldiethanolamine and the ethanolamine, diethanolamine and diisopropanolamine in the same series are used as the absorbent through screening and simulation of the carbon dioxide absorbent in the decarbonization zone.
In the technical scheme of the invention, the scheme of separating the olefin product from the low-temperature mixed hydrocarbon stream adopts a sequential separation method, namely the low-temperature mixed hydrocarbon stream is sent to a demethanizer to be separated firstly to obtain methane and components C2 and above, the components C2 and above are sent to a deethanizer to obtain components C2 and components C3, the components C2 are further separated to obtain an ethylene product in an ethylene separation tower, and the components C3 are further separated to obtain a propylene product in a propylene separation tower.
The technological scheme of the present invention includes cooling product gas, separating heavy hydrocarbon material flow containing four or more carbon components in depropanizing tower, eliminating carbon dioxide, carbon monoxide and hydrogen in light hydrocarbon material flow containing three or less carbon components in the decarbonizing zone and dehydrogenating zone, cooling the obtained mixed hydrocarbon material flow in the heat exchange zone to obtain low temperature mixed hydrocarbon material flow, and returning the obtained circulating material flow containing carbon monoxide and hydrogen to the olefin synthesizing reactor. In the separation process, the light hydrocarbon material flow is separated from the heavy hydrocarbon material flow by utilizing the reaction heat, so that the energy can be saved; only one part (light hydrocarbon material flow) in the product gas is sent to the decarbonization area and the dehydrogenation area, so that the utilization efficiency of equipment in the decarbonization area and the dehydrogenation area can be improved, the size of the equipment is reduced, and the investment cost is reduced; the recycle stream is returned to the reactor for preparing olefin from synthesis gas, so that the product yield is improved, the unit consumption of the device is reduced, and the device benefit is increased.
According to the technical scheme, by optimizing the separation process for preparing olefin from the synthesis gas, the heavy hydrocarbon material flow containing four or more carbon components and the light hydrocarbon material flow containing three or less carbon components are separated firstly, and are separated step by step according to a reasonable sequence through the serial connection of the optimized decarbonization area and the optimized dehydrogenation area, so that the unreacted raw materials are fully utilized, more diene products are obtained under the conditions of low energy consumption, low investment and high efficiency, and a good technical effect is achieved; when the absorbent is preferred, the energy consumption can be further reduced, and a better technical effect can be achieved.
The technical scheme adopted by the invention is applied to the separation process for preparing olefin from synthesis gas, particularly the technology for preparing olefin from synthesis gas by a one-step method, has greater advantages in the aspects of yield of diolefin, material consumption, energy consumption, wastewater yield and investment progression compared with the existing coal chemical technology, and particularly has more obvious advantages in the preferred scheme of the technical scheme.
The embodiment and the comparative example show that the technical scheme adopted by the invention is applied to the separation process for preparing olefin from synthesis gas, compared with the comparative example technology, the separation process has the advantages of high carbon dioxide removal rate, high carbon monoxide and hydrogen recovery rate, high yield and high recovery rate of ethylene products and propylene products, solves the problems that the subsequent separation process is influenced by a large amount of unconverted synthesis gas contained in product gas due to low conversion rate in the reaction process for preparing olefin from synthesis gas, and the equipment efficiency of carbon dioxide, carbon monoxide and hydrogen removal in the existing cryogenic separation technology is low, and has the advantages of high equipment efficiency, high product recovery rate, high product purity and low energy consumption in the separation process.
All publications, patent applications, patents, and other references mentioned in this specification are herein incorporated by reference in their entirety. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, including definitions, will control.
When the specification concludes with claims with the heading "known to those skilled in the art", "prior art", or the like, to derive materials, substances, methods, procedures, devices, or components, etc., it is intended that the subject matter derived from the heading encompass those conventionally used in the art at the time of filing this application, but also include those that are not currently in use, but would become known in the art to be suitable for a similar purpose.
In the context of the present specification, anything or things which are not mentioned, except where explicitly stated, are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein may be freely combined with one or more other embodiments described herein, and the technical solutions or concepts resulting therefrom are considered part of the original disclosure or original disclosure of the invention, and should not be considered as new matters not disclosed or contemplated herein, unless a person skilled in the art would consider such a combination to be clearly unreasonable.
The present invention will be further illustrated by the following examples, but is not limited to these examples.
Drawings
FIG. 1 is a separating device for preparing olefin by synthesis gas.
FIG. 2 is a schematic flow diagram of a separation process according to the present invention.
FIG. 3 is a schematic flow diagram of a separation process described in a comparative example.
FIG. 1 depicts the following:
11 is a carbon three carbon four separation zone (depropanizer)
13 is a decarburization zone
14 is a dehydrogenation zone
In fig. 1, the carbon three-carbon four separation zone is a depropanizer for separating carbon three and less components from carbon four and more components; the decarbonization area comprises an absorption tower and an analysis tower, and carbon dioxide is removed from the system by an absorption and analysis method; the dehydrogenation zone comprises one or at least one of a pressure swing adsorption unit, a temperature swing adsorption unit and a membrane separation unit and is used for removing hydrogen and carbon monoxide from the system.
FIG. 2 depicts the following:
101 product gas stream
102 is a light hydrocarbon stream
103 is a heavy hydrocarbon stream
104 is a carbon four stream
105 is a C5+ stream
106 is a carbon dioxide stream
107 is a decarbonated stream
108 is a recycle stream
109 is a mixed hydrocarbon stream
110 is a low temperature mixed hydrocarbon stream
111 is a methane stream
112 is a stream of components C2 and above
113 is a C2 component stream
114 is a C3 component stream
115 is a propylene product stream
116 is a propane stream
117 is an ethylene product stream
118 is an ethane stream
11 is a carbon three carbon four separation zone (depropanizer)
12 is a debutanizer
13 is a decarburization zone
14 is a dehydrogenation zone
15 is a heat exchange zone
16 is a demethanizer
17 is a deethanizer
18 is a propylene separating column
19 is an ethylene separation column
In fig. 2, a product gas stream 101 is separated by a depropanizer 11 to obtain a light hydrocarbon stream 102 containing three or less carbon components and a heavy hydrocarbon stream 103 containing four or more carbon components, the light hydrocarbon stream 102 is separated by a decarbonization zone 13 to obtain a carbon dioxide stream 106 mainly containing carbon dioxide components and a decarbonization stream 107, the decarbonization stream 107 is separated by a dehydrogenation zone 14 to obtain a recycle stream 108 mainly containing carbon monoxide and hydrogen and a mixed hydrocarbon stream 109, the mixed hydrocarbon stream 109 is cooled by a heat exchange zone 15 to obtain a low-temperature mixed hydrocarbon stream 110, and at least part of the recycle stream 108 is returned to a synthesis gas olefin preparation reactor; the low-temperature mixed hydrocarbon stream 110 is sent to a demethanizer 16 to be separated firstly to obtain a methane stream 111 and a C2 component stream 112 and above, the C2 component stream 112 and above is sent to a deethanizer 17 to obtain a C2 component stream 113 and a C3 component stream 114, the C2 component stream 113 is further separated into an ethylene product stream 117 and an ethane stream 118 in an ethylene separation tower 19, and the C3 component stream is further separated into a propylene product stream 115 and a propane stream 116 in a propylene separation tower 18; the heavy hydrocarbon stream 103 is separated in the debutanizer 12 to produce a carbon four stream 104 containing carbon four components and a stream 105 containing carbon five and above components C5 +.
FIG. 3 illustrates in labeled form:
201 is product gas
202 is decarbonized product gas
203 is carbon dioxide
204 is unconverted synthesis gas
205 is pressure swing adsorption product gas
206 is the first unconverted synthesis gas and methane
207 is a second unconverted synthesis gas and methane
208 is an ethylene product
209 is an ethane product
210 is a propylene product
211 is a propane product
212 is a carbon four product
213 is a gasoline product.
21 is a dryer
22 is an absorption tower
23 is a regeneration tower
24 is a pressure swing adsorption device
25 is a carbon separation tank
26 is a demethanizer
27 is a deethanizer
28 is an ethylene rectifying tower
29 is a depropanizer
30 is a propylene rectifying tower
31 is a debutanizer.
In fig. 3, a product gas 201 enters a dryer 21 to remove a small amount of moisture, then enters an absorption tower 22 to perform mass transfer and heat transfer with an MDEA solvent, a carbon dioxide component in the gas is absorbed, then a carbon dioxide material stream 203 is released from the top of a regeneration tower 23, a purified product gas, namely a decarbonized product gas 202, is led out from the top of the absorption tower 22 and sent to a pressure swing adsorption device 24, the content of H2 and CO components in the product gas subjected to pressure swing adsorption is greatly reduced, the pressure swing adsorption product gas 205 is subjected to cryogenic cooling and then sent to a carbon-first separation tank 25 and a demethanizer 26 to separate unconverted synthesis gas and methane, and the remaining mixed hydrocarbons enter a deethanizer 27 to complete the separation of carbon dioxide, carbon three and heavy components. The materials at the top of the deethanizer 27 mainly comprise ethylene and a small amount of ethane, the materials are rectified and separated by the ethylene rectifying tower 28, a polymer-grade ethylene product 208 is obtained at the top of the tower, an ethane material flow is obtained at the bottom of the tower, the materials at the bottom of the deethanizer 27 mainly comprise carbon three and heavy components, the separation of the carbon three and the heavy components is completed by the depropanizer 29, the materials at the top of the depropanizer 29 mainly comprise propylene and a small amount of propane, the materials are rectified and separated by the propylene rectifying tower 30, a polymer-grade propylene product 210 is obtained at the top of the tower, and a propane material flow is obtained at the bottom of the tower; the tower bottom material composition of the depropanizing tower 29 is mainly carbon four and heavy components, and the separation of the carbon four and the heavy component gasoline is completed through the debutanizing tower 31 to obtain a carbon four product 212 and a gasoline product 213.
Detailed Description
By taking a product gas stream with the flow rate of 800000 kgh as a reference, adopting the technical scheme of the separation device and the method in the technology, in order to compare with the technical scheme of a comparative example, the separation device for preparing olefin from synthesis gas shown in fig. 1 is further expanded, the olefin product is separated, namely, the flow schematic diagram of the separation method in the invention shown in fig. 2, the technical scheme and the technical scheme of the comparative example shown in fig. 2 are adopted, and the heat exchange areas in the two schemes are used for respectively cooling the mixed hydrocarbon material and the pressure swing adsorption product gas to below 100 ℃, so as to compare the carbon dioxide removal rate, the carbon monoxide and hydrogen recovery rate, the yields and the recovery rates of the ethylene product and the propylene product, and the energy consumption.
[ example 1 ]
The product stream obtained from the reaction zone comprises: 25.00 percent of carbon dioxide, 3.40 percent of hydrogen, 46.40 percent of carbon monoxide and 15.70 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning 76 percent of a circulating material flow to a reactor for preparing olefin from synthesis gas, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was at a temperature of 105 deg.C below zero and a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.64 percent, the carbon monoxide recovery rate is 98.98 percent, the hydrogen recovery rate is 98.18 percent, the ethylene product yield is 2.63 percent higher than that of the technical scheme of the comparative example, the recovery rate is 97.3 percent, the propylene product yield is 2.68 percent higher than that of the technical scheme of the comparative example, the recovery rate is 99.85 percent, and the energy consumption is 1.85 percent less than that of the technical scheme of the comparative example.
[ example 2 ]
The product stream obtained from the reaction zone comprises: 25.00 percent of carbon dioxide, 3.40 percent of hydrogen, 46.40 percent of carbon monoxide and 15.70 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning 86 percent of a circulating material flow to a reactor for preparing olefin from synthesis gas, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was at a temperature of-110 deg.C and a pressure of 3.4 MPaG.
The carbon dioxide removal rate is 98.63%, the carbon monoxide recovery rate is 98.97%, the hydrogen recovery rate is 98.17%, the ethylene product yield is 2.97% higher than that of the technical scheme of the comparative example, the recovery rate is 97.4%, the propylene product yield is 3.03% higher than that of the technical scheme of the comparative example, the recovery rate is 99.88%, and the energy consumption is 1.84% lower than that of the technical scheme of the comparative example.
[ example 3 ]
The product stream obtained from the reaction zone comprises: 25.00 percent of carbon dioxide, 3.40 percent of hydrogen, 46.40 percent of carbon monoxide and 15.70 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning 96 percent of a circulating material flow to a reactor for preparing olefin from synthesis gas, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was at 115 deg.C below zero and a pressure of 3.3 MPaG.
The carbon dioxide removal rate is 98.62%, the carbon monoxide recovery rate is 98.96%, the hydrogen recovery rate is 98.16%, the ethylene product yield is 3.32% higher than that of the technical scheme of the comparative example, the recovery rate is 97.5%, the propylene product yield is 3.38% higher than that of the technical scheme of the comparative example, the recovery rate is 99.91%, and the energy consumption is 1.83% lower than that of the technical scheme of the comparative example.
[ example 4 ]
The product stream obtained from the reaction zone comprises: 25.00 percent of carbon dioxide, 3.40 percent of hydrogen, 46.40 percent of carbon monoxide and 15.70 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning all the recycle stream to a synthesis gas olefin preparation reactor, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 120 ℃ at zero temperature and a pressure of 3.2 MPaG.
The carbon dioxide removal rate is 98.60%, the carbon monoxide recovery rate is 98.95%, the hydrogen recovery rate is 98.15%, the ethylene product yield is 3.46% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 3.53% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 1.82% lower than that of the technical scheme of the comparative example.
[ example 5 ]
The product stream obtained from the reaction zone comprises: 20.00 percent of carbon dioxide, 3.05 percent of hydrogen, 40.35 percent of carbon monoxide and 27.1 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning all the recycle stream to a synthesis gas olefin preparation reactor, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.1 MPaG.
The carbon dioxide removal rate is 98.60%, the carbon monoxide recovery rate is 98.96%, the hydrogen recovery rate is 98.16%, the ethylene product yield is 5.97% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 6.09% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 1.86% lower than that of the technical scheme of the comparative example.
[ example 6 ]
The product stream obtained from the reaction zone comprises: 20.00 percent of carbon dioxide, 3.05 percent of hydrogen, 40.35 percent of carbon monoxide and 27.1 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting diethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning all the recycle stream to a synthesis gas olefin preparation reactor, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.60%, the carbon monoxide recovery rate is 98.96%, the hydrogen recovery rate is 98.16%, the ethylene product yield is 5.97% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 6.09% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 1.86% lower than that of the technical scheme of the comparative example.
[ example 7 ]
The product stream obtained from the reaction zone comprises: 20.00 percent of carbon dioxide, 3.05 percent of hydrogen, 40.35 percent of carbon monoxide and 27.1 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting sodium carbonate as an absorbent in a decarbonization zone, adopting a PSA separation method in a dehydrogenation zone, returning all the circulating material flow to a synthesis gas olefin preparation reactor, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.58%, the carbon monoxide recovery rate is 98.96%, the hydrogen recovery rate is 98.16%, the ethylene product yield is 5.97% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 6.09% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 1.84% lower than that of the technical scheme of the comparative example.
[ example 8 ]
The product stream obtained from the reaction zone comprises: 20.00 percent of carbon dioxide, 3.05 percent of hydrogen, 40.35 percent of carbon monoxide and 27.1 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, adopting sodium carbonate as an absorbent in a decarburization area, adopting a membrane separation method in a dehydrogenation area, returning all the circulating material flow to a reactor for preparing olefin from synthesis gas, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.58%, the carbon monoxide recovery rate is 98.97%, the hydrogen recovery rate is 98.15%, the ethylene product yield is 5.97% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 6.09% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 1.85% lower than that of the technical scheme of the comparative example.
[ example 9 ]
The product stream obtained from the reaction zone comprises: 20.00 percent of carbon dioxide, 3.05 percent of hydrogen, 40.35 percent of carbon monoxide and 27.1 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 2, and the difference is that in the other technical scheme of the heavy hydrocarbon material flow, a mixed carbon four material flow containing four to six carbon components and a carbon seven material flow containing seven or more carbon components are obtained by separation in a dehexanizer, the carbon four material flow can be sent into an olefin cracking device to crack olefin components into a crude propylene material flow mainly containing ethylene and propylene, and the crude propylene material flow is sent into a depropanizer as a feed. The decarbonization zone adopts sodium carbonate as an absorbent, the dehydrogenation zone adopts a membrane separation method, all the circulating material flow returns to a synthesis gas olefin preparation reactor, and ethylene products and propylene products are obtained through separation.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.58%, the carbon monoxide recovery rate is 98.97%, the hydrogen recovery rate is 98.15%, the ethylene product yield is 9.88% higher than that of the technical scheme of the comparative example, the recovery rate is 97.6%, the propylene product yield is 10.02% higher than that of the technical scheme of the comparative example, the recovery rate is 99.94%, and the energy consumption is 2.53% lower than that of the technical scheme of the comparative example.
[ COMPARATIVE EXAMPLE 1 ]
The product stream obtained from the reaction zone comprises: 25.00 percent of carbon dioxide, 3.40 percent of hydrogen, 46.40 percent of carbon monoxide and 15.70 percent of mixed hydrocarbon, adopting the technical scheme shown in figure 3, adopting methyldiethanolamine as an absorbent in a decarburization area, adopting a PSA separation method in a dehydrogenation area, returning all the recycle stream to a synthesis gas olefin preparation reactor, and separating to obtain an ethylene product and a propylene product.
The low temperature mixed hydrocarbon stream was 125 deg.C below zero and at a pressure of 3.5 MPaG.
The carbon dioxide removal rate is 98.40%, the carbon monoxide recovery rate is 98.60%, the hydrogen recovery rate is 98.00%, the ethylene product recovery rate is 97.2%, and the propylene product recovery rate is 99.80%.

Claims (19)

1. A separation unit for producing olefins from synthesis gas, comprising:
1) a carbon-three-carbon-four separation zone; configured to receive the product gas stream and discharge a light hydrocarbon stream and a heavy hydrocarbon stream;
2) a decarbonization zone; configured to receive the light hydrocarbon stream, to emit a carbon dioxide stream and a decarbonated stream;
3) a dehydrogenation zone; configured to receive the decarbonated stream and discharge a recycle stream and a mixed hydrocarbon stream.
2. The separation device for the preparation of olefins from synthesis gas according to claim 1, characterized in that it further comprises sequential separation zones; configured to receive the mixed hydrocarbon stream and discharge an olefin product.
3. The separation device for preparing the olefin by the synthesis gas as claimed in claim 1 or 2, characterized in that a heat exchange zone is further included between the dehydrogenation zone and the sequential separation zone.
4. The separation plant for the preparation of olefins from synthesis gas according to claim 1, characterized in that the separation zone of the carbon three carbon four separation zone comprises a depropanizer.
5. The separation plant for the preparation of olefins from synthesis gas according to claim 1, characterized in that the decarbonization section comprises an absorption column and a stripper column.
6. The separation device for producing olefin from synthesis gas according to claim 1, characterized in that the dehydrogenation zone comprises one or at least one of a pressure swing adsorption device, a temperature swing adsorption device, and a membrane separation device.
7. The separation unit for synthesis gas to olefins according to claim 3, characterized in that the heat exchange zone comprises a heat exchanger; it is preferable to use a heat exchanger containing ethylene as a refrigerant.
8. The separation plant for the preparation of olefins from synthesis gas according to claim 2, characterized in that the sequential separation zones comprise a demethanizer, a deethanizer, an ethylene rectifier and a propylene rectifier.
9. The separation unit for the production of olefins from synthesis gas according to claim 1, characterized in that the separation unit further comprises a debutanizer.
10. A separation method for preparing olefin by synthesis gas comprises the following steps:
a) separating the product gas stream by a carbon-three-carbon-four separation zone to obtain a light hydrocarbon stream containing three or less carbon components and a heavy hydrocarbon stream containing four or more carbon components;
b) separating the light hydrocarbon material flow into a carbon dioxide material flow mainly containing carbon dioxide components and a decarbonization material flow through a decarbonization area;
c) the decarbonated stream is separated in a dehydrogenation zone into a recycle stream comprising primarily carbon monoxide and hydrogen and a mixed hydrocarbon stream.
11. The separation process for preparing olefin from synthesis gas according to claim 10, wherein the mixed hydrocarbon stream is cooled in the heat exchange zone to obtain a low-temperature mixed hydrocarbon stream.
12. The process of claim 10, wherein the low temperature mixed hydrocarbon stream is further fed to sequential separation zones for further separation to obtain olefin products.
13. The separation process for synthesis gas to olefins according to claim 10, characterized in that the product gas stream is at least partially derived from a synthesis gas to olefins reactor; optionally, at least part of the recycle stream obtained in step c) is returned to the synthesis gas to olefins reactor.
14. The separation process for olefins production from synthesis gas according to claim 10, characterized in that the carbon dioxide is separated by absorption and desorption in the decarbonization zone.
15. A separation process for olefins from synthesis gas according to claim 10, characterized in that the decarbonization zone has the formation of bicarbonate ions.
16. The separation process for olefins from synthesis gas according to claim 10, characterized in that carbon monoxide or/and hydrogen is separated in the dehydrogenation zone using one or at least one of a PSA separation process and a membrane separation process.
17. The separation process for the preparation of olefins from synthesis gas according to claim 10, characterized in that the low temperature mixed hydrocarbon stream has a temperature of-100 ℃ or lower; preferably 105 ℃ or lower.
18. The separation process for synthesis gas to olefins according to claim 10, characterized in that the low temperature mixed hydrocarbon stream pressure is equal to or greater than 3.0 MPaG; preferably 3.1MPaG or more.
19. The separation method for preparing olefin hydrocarbon by synthesis gas according to claim 10, characterized in that the heavy hydrocarbon stream obtained in the step a) is separated by a debutanizer to obtain a carbon-containing four-component carbon-four stream and a carbon-containing five and more component C5+ stream.
CN201811275352.2A 2018-10-30 2018-10-30 Separation device and method for preparing olefin from synthesis gas Pending CN111116297A (en)

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