CN112174766B - Method and apparatus for purifying a low carbon olefin containing stream - Google Patents
Method and apparatus for purifying a low carbon olefin containing stream Download PDFInfo
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Abstract
The invention provides a method for purifying a low-carbon olefin-containing stream, which comprises the following steps: (i) providing a feed stream; (ii) performing a heavy oil wash in a heavy oil wash column; (iii) performing low temperature light oil washing in a light oil wash column; (iv) Separating the hydrocarbon-rich heavy oil wash stream to obtain a first product stream comprising C2-C8 olefins; (v) Separating the hydrocarbon-rich light oil wash stream to produce a second product stream comprising C2-C4 olefins; (vi) Separating the first and second product streams to obtain mixed or independent C2-C4 olefin, C2-C4 alkane, fuel gas and the like. The invention also provides equipment for purifying the low-carbon olefin stream.
Description
Technical Field
The application mainly relates to the technical field of hydrocarbon mixture separation, in particular to a method and equipment for recovering and separating low-carbon olefins from Fischer-Tropsch synthesis tail gas or synthesis gas olefin synthesis tail gas, which are used for recovering and separating the low-carbon olefins from the synthesis tail gas and obtaining high-quality polymer grade olefin products.
Background
The low-carbon olefin mainly containing ethylene and propylene is the most important basic raw material in the chemical industry. The traditional ethylene and propylene sources are mainly petroleum hydrocarbon steam cracking, and a large amount of petroleum resources are consumed. The resource characteristics of China are rich in coal and less in oil, more than 72% of oil demand needs to be imported in 2019, the international situation is increasingly tense in recent years, the oil supply is increasingly tense, and in order to relieve the serious dependence on oil resources and reduce the oil, the non-oil route olefin production becomes the domestic mainstream technology, and researchers have invested a great deal of intensive research on the technology. The route of preparing the synthetic gas from the coal and then preparing the olefin from the synthetic gas has the advantages of short flow, low energy consumption and the like. Coal to olefins process (e.g. Fischer-Tropsch F-T synthesis or syngas)FTO reaction for directly preparing olefin) has the great defects that the conversion rate of the catalyst is lower than that of other processes, and synthetic tail gas formed by condensing and separating reactor outlet gas still contains a great amount of H 2 、CO、CO 2 And the content of the low-carbon hydrocarbon components is low, so that the problem of difficulty in separating the low-carbon hydrocarbon components is brought, therefore, the synthetic tail gas is mainly used as fuel gas to be directly burnt, or other components are used as fuel to be burnt after hydrogen is recovered by methods such as PSA (pressure swing adsorption), membrane separation and the like, a large amount of low-carbon hydrocarbons are wasted, and the use value of resources is greatly reduced.
At present, light hydrocarbon separation processes adopted at home and abroad mainly comprise cryogenic and medium-cold oil washing processes, but for the coal-to-olefin process product flow with low content of low-carbon olefin, the two processes in the prior art can not realize satisfactory low-carbon olefin separation and recovery effects at reasonable cost. For example, if the Fischer-Tropsch synthesis tail gas is subjected to cryogenic separation in a simple step-by-step condensation manner, expensive and complicated large-scale cryogenic cooling box equipment is used for achieving high olefin recovery, and the high capital construction and operation cost seriously hinders the wide industrial application of the technology. Some prior arts adopt intercooling oil washing to avoid the defects of the cryogenic process, but the process can cause the impurity content in the product to exceed the standard and the recovery efficiency of the same olefin to be lower, a large amount of target products of the olefin cannot be recovered, so that the resource waste is greatly caused, and different products are difficult to subdivide and cut, and are not suitable for the recovery and separation of Fischer-Tropsch or FTO reaction products.
Therefore, there is a strong need to develop new purification methods and apparatus, and it is desirable to achieve high recovery and fine separation of lower olefins in fischer-tropsch or FTO reaction products with lower cost and more convenient methods and apparatus.
Disclosure of Invention
The present inventors have conducted extensive and intensive studies to achieve the above-mentioned objects in a low-cost and convenient manner by improving process steps and purification equipment, and have thus completed the present invention. In one aspect of the invention, the invention provides a process for purifying a lower olefin containing stream, the process comprising:
step (i): providing a feed stream comprising C2 to C4 olefins;
step (ii): conveying the raw material flow into a heavy oil washing tower, and washing the raw material flow by using a heavy oil lotion in the heavy oil washing tower to obtain a hydrocarbon-rich heavy oil lotion flow and a gas phase flow at the top of the heavy oil washing tower;
step (iii): cooling the gas phase flow at the top of the heavy oil washing tower, conveying the cooled gas phase flow into a light oil washing tower, and washing the gas phase flow at the top of the heavy oil washing tower by using a low-temperature light oil lotion to obtain a hydrocarbon-rich light oil lotion flow and a gas phase flow at the top of the light oil washing tower;
step (iv): separating the hydrocarbon-rich heavy oil wash stream to yield a circulating heavy oil wash and a first product stream comprising C2-C8 olefins;
step (v): separating the hydrocarbon-rich light oil wash stream to obtain a recycle light oil wash and a second product stream comprising C2-C4 olefins;
step (vi): separating the first product stream and the second product stream to obtain C2-C4 olefins in a mixed or separate state.
According to one embodiment of this first aspect, in step (vi), the first and second products are each, independently or after being combined, subjected to the following treatments: (a) separating the C4-components and the C5+ components in a debutanizer column. According to another embodiment of the first aspect, (b) the C4-components obtained in step (a) are pressurized and sent to a depropanizer column, the C3-components are separated from the C4-components, and the C4-components are sent to a butene column to separate butane and butene. According to another embodiment of the first aspect, (C) the C3-component obtained in step (b) is subjected to multi-stage condensation and multi-stage separation to separate ethylene, propylene, methane, ethane and propane therefrom.
According to another embodiment of this first aspect, for said step (ii), the heavy oil wash is a C9-C18 hydrocarbon, preferably a C9-C13 hydrocarbon.
According to another embodiment of this first aspect, for said step (ii), the pressure in the heavy oil wash column is from 1.5 to 4.0MPaG, preferably from 2.2 to 3.0MPaG.
According to another embodiment of this first aspect, for said step (iii), the light oil wash is a C5-C7 hydrocarbon, and said light oil wash may be any one of C5-C7 hydrocarbons, or a mixture of two or more C5-C7 hydrocarbons.
According to another embodiment of this first aspect, for said step (iii), the pressure in the light oil wash column is from 1.5 to 4.0MPaG, preferably from 2.2 to 3.0MPaG, and the temperature is from-20 to-75 ℃, preferably from-24 to-40 ℃.
According to another embodiment of this first aspect, the circulating heavy oil wash and optionally fresh makeup heavy oil wash are delivered to the heavy oil wash column; the recycled light oil wash and optionally fresh makeup light oil wash are delivered to the light oil wash column.
According to another embodiment of this first aspect, before said step (i) there is further included the step of: providing a crude feed stream comprising C1-C4 alkanes, C2-C4 alkenes, C5+ hydrocarbons, oxygenated organic compounds, and optionally carbon monoxide, carbon dioxide, hydrogen, and water vapor, pretreating the crude feed stream to at least partially remove the oxygenated organic compounds, carbon dioxide, and water to obtain the feed stream.
In a second aspect of the present invention, there is provided an apparatus for purifying a lower olefin containing stream, said purification apparatus comprising: heavy oil wash tower, light oil wash tower, heavy oil lotion regenerator and light oil lotion regenerator.
According to an embodiment of this second aspect, the purification apparatus further comprises at least one of the following: a debutanizer, a depropanizer, a butene tower, a multi-stage condensing and separating unit, a demethanizer, a deethanizer, a propylene tower, and an ethylene tower.
According to a preferred embodiment of this second aspect, the purification apparatus comprises the following means and their connections:
the raw material flow supply device is connected to the inlet of the heavy oil washing tower through a pipeline, the outlet of the top of the heavy oil washing tower is connected with the inlet of the synthesis tail gas cooler, and the outlet of the synthesis tail gas cooler is connected with the inlet of the low-temperature light oil washing tower;
the gas phase outlet of the low-temperature light oil washing tower is connected with the inlet of an expansion machine, the outlet of the expansion machine is connected with the other inlet of the synthesis gas cooler, the other outlet of the synthesis gas cooler is connected with the inlet of a synthesis tail gas reheater, and the outlet of the reheater is connected with the inlet of a synthesis reactor;
an outlet of a tower kettle of the heavy oil washing tower is connected with an inlet of a heat exchanger for the lean and rich heavy oil washing agent, an outlet of the heat exchanger for the lean and rich heavy oil washing agent is connected with an inlet of a heavy oil washing agent regeneration tower, an outlet of the tower top of the heavy oil washing agent regeneration tower is connected with an inlet at the bottom of a debutanizer, an outlet of the tower kettle of the heavy oil washing agent is connected with the other inlet of the heat exchanger for the lean and rich heavy oil washing agent, and the other outlet of the heat exchanger for the lean and rich heavy oil washing agent is connected with an inlet at the tower top of the heavy oil washing tower;
the outlet of the tower kettle of the low-temperature light oil washing tower is connected with the inlet of a lean and rich light oil lotion heat exchanger, the outlet of the lean and rich light oil lotion heat exchanger is connected with the inlet of a light oil lotion regeneration tower, the gas phase outlet of the light oil lotion regeneration tower is connected with the inlet at the upper part of the debutanizer, the outlet of the tower kettle is connected with the other inlet of the lean and rich light oil lotion heat exchanger, and the other outlet of the lean and rich light oil lotion is connected with the inlet at the top of the low-temperature light oil washing tower;
the gas phase outlet of the debutanizer is connected with the inlet of a desorption gas compressor, the outlet of the compressor is connected with the inlet of the depropanizer, and the kettle outlet of the depropanizer is connected with the inlet of a butene tower;
the outlet of the tower top of the depropanizing tower is connected with the inlet of the compressor between stages, the outlet of the compressor tail section is connected with the inlet of a first-stage condenser, the outlet of the first-stage condenser is connected with the inlet of a second-stage condenser, the outlet of the second-stage condenser is connected with the inlet of a first-stage separator, the gas phase outlet of the first-stage separator is connected with the inlet of a third-stage condenser, the outlet of the third-stage condenser is connected with the inlet of a fourth-stage condenser, and the outlet of the fourth-stage condenser is connected with the inlet of the second-stage separator;
1. the liquid phase outlet of the second-stage separator is respectively connected with the upper inlet and the lower inlet of the demethanizer, the gas phase outlet of the demethanizer and the gas phase outlet of the second-stage separator are connected with a fuel gas pipeline, the liquid phase outlet of the demethanizer is connected with the inlet of the deethanizer, the gas phase outlet of the deethanizer is connected with the inlet of the ethylene tower, and the liquid phase outlet of the deethanizer is connected with the inlet of the propylene tower.
Some embodiments of the present application will be described below with reference to the accompanying drawings.
Drawings
An illustration of the method and apparatus of the present invention is shown in the drawings, in which:
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a flow chart of heavy oil washing and light oil washing according to one embodiment of the present invention;
FIG. 3 is a flow chart of heavy oil washing and light oil washing according to another embodiment of the present invention;
FIG. 4 is a flow diagram for separating C4-components according to one embodiment of the present invention.
In the drawings, the names of the devices or streams corresponding to the respective reference numerals are as follows:
s100-synthesizing tail gas; s201, circulating synthesis gas; s202-resolving C5+ hydrocarbons; s202-2, washing with heavy hydrocarbon light oil; s203-resolving the C4-component; s204, supplementing the light oil lotion; s205-replenishing the heavy oil lotion; s206-circulating the light oil lotion; s207-a hydrocarbon-rich light oil wash; s208-circulating the heavy oil wash; s209-hydrocarbon-rich heavy oil wash; s210, regenerating and decomposing gas by using the heavy oil lotion; s211-light oil wash regeneration gas.
KT 201-expander.
T201-heavy oil washing tower; t202-heavy oil wash regenerator; t203-low temperature light oil wash tower; t204-light oil lotion regeneration tower; t205 debutanizer.
E201-lean and rich heavy oil wash heat exchanger; e202-synthesis tail gas cooler; e203-lean-rich light oil wash heat exchanger; e204-recycle synthesis gas reheater.
S301-pressurized desorption gas (C4-light hydrocarbon); s302-polymer grade butene; s303-butane; S304-Fuel gas (H) 2 、CO、CH 4 ) (ii) a S305 — polymer grade ethylene; s306-ethane; s307-polymerization grade propylene; s308-propane.
K301-analytic gas compressor.
V301 — first stage separator; v302-two stage separator.
E301-first stage condenser; e302-secondary condenser; e303-a three-stage condenser; e304-four-stage condenser.
T301-depropanizer; a T302-butene column; t303-a demethanizer; t304-deethanizer; a T305-propene column; t306-ethylene column.
Detailed Description
The "ranges" disclosed herein are expressed in terms of lower and upper limits. There may be one or more lower limits, and one or more upper limits, respectively. The given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this manner are inclusive and combinable with each other, i.e., any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for particular parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Further, if the minimum range values listed are 1 and 2, and the maximum range values are 3,4, and 5, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.
In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers.
In this application, the word "above" or "below" following a number includes the word. For example, "5 or less" means 5 or less, and "7 or more" means 7 or more.
In the present application, all embodiments and preferred embodiments mentioned herein may be combined with each other to form new solutions, if not specifically stated.
In the present application, all the technical features mentioned herein as well as preferred features may be combined with each other to form new technical solutions, if not specifically stated.
In the present application, all steps mentioned herein may be performed sequentially or randomly, if not specifically stated, but preferably sequentially. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, and may also comprise steps (b) and (a) performed sequentially. For example, reference to the process further comprising step (c) means that step (c) may be added to the process in any order, for example, the process may comprise steps (a), (b) and (c), may also comprise steps (a), (c) and (b), may also comprise steps (c), (a) and (b), etc.
In the present application, the term "comprising" as used herein means either an open type or a closed type unless otherwise specified. For example, the term "comprising" may mean that other components not listed may also be included, or that only listed components may be included.
In the present application, the term "lower olefin" is used to denote a C2-C8 olefin, specifically including ethylene, propylene, butene, pentene, hexene, heptene, and octene, preferably a C2-C6 olefin, and more preferably a C2-C4 olefin. In the present application, the term "lower hydrocarbon", "lower component" or "lower fraction" means a hydrocarbon having a carbon number of 4 or less, and preferably includes C2-C4 olefins and C1-C4 alkanes (also referred to as lower alkanes).
In the present application, the term "stream" means any flowable material fluid used or processed in the methods and apparatus of the present application, having objectively present material properties and flowable properties, which may include a gas, a liquid, a mixture of a gas and a liquid, a mixture of a liquid and a liquid, a solution of a gas in a liquid, a solution of a liquid in a liquid, a solution or suspension of a solid in a liquid, or a combination of one or more of the foregoing. For example, in the present application, a product containing lower olefins [ e.g., a product containing the lower olefins obtained from a fischer-tropsch (FT) reaction, a synthesis gas to olefins (FTO) reaction, or any other process ], which is an object of purification, any portion separated from these products (e.g., a light hydrocarbon fraction separated from the product), and any substance or fraction added thereto or recovered therefrom during processing, may be referred to as a "stream".
In this application, "fractionation section," "distillate stream," "distillate," and the like are used interchangeably.
In embodiments of the present invention, depending on the particular source, preparation process and separation technique of the feed stream to be purified, it is also possible to include other unavoidable impurities in lower proportions, but in very low amounts, which are substantially simultaneously removed during the separation and purification processes of the present application, and in acceptable levels in the final various lower olefin products, and therefore no particular attention is paid to the separation of these impurities in the technical solutions of the present application. The hydrocarbon compounds with the same carbon number comprise normal paraffin, isoparaffin and olefin, and the oxygen-containing compounds with the same carbon number comprise alcohol, aldehyde, ketone, acid and isomers thereof. According to one embodiment of the invention, the 'stream containing low-carbon olefins' processed by the method and the device can be a gas-phase product of a Fischer-Tropsch (FT) reaction or synthesis gas direct olefin (FTO), and can also be a gas-phase light hydrocarbon fraction obtained by performing a preliminary separation on the Fischer-Tropsch (FT) reaction or the synthesis gas direct olefin (FTO). The Fischer-Tropsch (FT) reaction and the process for directly preparing olefin (FTO) from synthesis gas are processes for synthesizing hydrocarbon mixtures with various carbon numbers by taking the synthesis gas (mixed gas of carbon monoxide and hydrogen) as a raw material under a catalyst and proper conditions, wherein the product contains the low-carbon olefin serving as a target product, and the content of olefin substances is far greater than that of alkane substances. It is emphasized that although the present invention is primarily described in terms of low carbon separation and purification using a fischer-tropsch (FT) reaction or a syngas direct to olefins (FTO) product or product light hydrocarbon cut section, the method and apparatus of the present invention is applicable to any mixed hydrocarbon stream containing lower olefins. According to a preferred embodiment of the present invention, the lower olefin-containing material to be separated and purified is a light hydrocarbon fraction of hydrocarbon products produced by a Fischer-Tropsch (FT) reaction or a direct synthesis gas to olefins (FTO) process.
In addition, in the present application, cn hydrocarbons (e.g., C2 fraction, C3 fraction, or C4 fraction, etc.) are used to refer to an aggregate or mixture of hydrocarbons having n carbon atoms, e.g., C2 hydrocarbons refer to an aggregate or mixture of hydrocarbons having 2 carbon atoms. By Cn + hydrocarbons is meant herein a collection or mixture of hydrocarbons having n or more carbon atoms, for example C5+ hydrocarbons refers to a collection or mixture of hydrocarbons having 5 or more carbon atoms; by Cn-hydrocarbons is meant in this application an aggregate or mixture of hydrocarbons having n or fewer carbon atoms, for example C4-hydrocarbons refers to an aggregate or mixture of hydrocarbons having 4 or fewer carbon atoms.
The above expressions are also expressions conventionally employed in the art. It is emphasized that the embodiments shown in the drawings and described below are merely exemplary embodiments of the invention, to the extent that the scope of the invention is not limited to these embodiments. The scope of the invention is defined by the claims and may include any embodiments within the scope of the claims, including but not limited to further modifications and alterations to these embodiments.
The method and apparatus of the present invention will now be described in detail with reference to fig. 1-4. FIG. 1 shows a schematic diagram of the process for purifying lower olefins according to the present invention. According to the embodiment shown in fig. 1, a synthesis gas as a raw material is fed to a synthesis reaction unit, in which a synthesis reaction [ e.g., a fischer-tropsch (FT) reaction or a synthesis gas direct olefin (FTO) process ] is performed to produce a crude product stream containing C2 to C4 olefins as a target component, and further containing C1 to C4 alkanes, C5+ hydrocarbons, carbon monoxide, carbon dioxide, oxygen-containing organic compounds (e.g., various alcohols, aldehydes, carboxylic acids), water vapor, and a trace amount of other impurities. As mentioned above, other reactions may also be carried out in the reaction unit using other feedstocks to obtain a stream comprising lower olefins for subsequent operations.
The crude product stream is condensed and separated, pressurized to a suitable pressure by a compressor, and then pretreated in a pretreatment unit to remove oxygen-containing organic compounds and CO 2 Water vapour and a portion of heavy hydrocarbons (for example C5+ hydrocarbons), thereby obtaining a synthesis tail gas S100, which synthesis tail gas S100 is sent to a subsequent heavy oil washing anda low temperature light oil washing unit. The synthesis tail gas S100 is separated by a heavy oil lotion and a low-temperature light oil lotion in the washing units in sequence, the separated cycle synthesis gas S201 is sent to a synthesis reaction unit after expansion refrigeration and external work and is used for carrying out Fischer-Tropsch (FT) reaction or a process for directly preparing olefins (FTO) from synthesis gas, and C5+ hydrocarbons separated from the heavy oil washing and light oil washing units and heavy hydrocarbons separated from the pretreatment unit are separated in a heavy hydrocarbon separation unit, so that the heavy oil lotion and the light oil lotion are respectively provided for the two washing units. And the low-carbon olefin-containing material flow separated from the heavy oil washing and light oil washing unit is conveyed to a low-carbon olefin separation unit at the downstream, and various low-carbon olefins and alkane products with different carbon numbers are further separated and recovered.
Referring next to fig. 2, the synthesis tail gas S100 obtained after passing through the synthesis reaction unit and the pretreatment unit mainly comprises C2-C4 olefins, C1-C5 alkanes, a certain amount of C5+ hydrocarbons, hydrogen and carbon monoxide, the synthesis tail gas S100 enters the heavy oil washing tower T201 from the bottom, at the same time, the heavy oil washing agent S208 (having components of C9-C18, preferably C9-C13) is fed into the heavy oil washing tower T201 from the top, the two streams are contacted in a counter-current manner, almost all the C5+ hydrocarbons in the synthesis tail gas S100 are removed by washing with heavy oil, and part of the H + hydrocarbons are washed at the same time 2 CO, C1-C4 alkanes and C2-C4 alkenes. The bottom hydrocarbon-rich heavy oil wash S209 flowing out from the bottom of the column mainly contains the heavy oil wash and the above-mentioned washed components, and almost all the C5+ hydrocarbons are removed from the stream discharged from the top of the column. According to one embodiment of the invention, the heavy oil wash column is operated at a pressure of 1.5 to 4.0MPaG, preferably 2.2 to 3.0MPaG, and at a temperature of 0 to 50 deg.C, for example 20 to 40 deg.C.
In the embodiment shown in fig. 2, the bottom hydrocarbon-rich heavy oil wash S209 is heat-exchanged with the circulating heavy oil wash S208 (since it has removed the target hydrocarbons in the regeneration tower T202, compared with the "hydrocarbon-rich" wash, this S208 is also referred to herein as a lean oil wash, that is, in this application, the terms of circulating heavy oil wash S208 and lean oil wash are used interchangeably) output from the heavy oil wash regeneration tower T202, and then enters the heavy oil wash regeneration tower T202 after heat exchange in the lean and rich heavy oil wash heat exchanger E201, and the T202 overhead resolved gas S210 mainly contains components separated from the heavy oil wash and may also contain a certain amount of heavy oil (for example, the wash may contain hydrogen, carbon monoxide, a few C1-C4 alkanes, a few C2-C4 alkenes, C5+ hydrocarbons, etc.) and enters the debutanizer T205, and the regenerated lean oil wash output from the bottom of the T202 tower is heat-exchanged with the E201 and then used as the circulating heavy oil wash S208. Since a certain portion of the heavy oil wash loss in the above process needs to be replenished, as shown in fig. 2, a replenished heavy oil wash S205 is supplied from the heavy hydrocarbon separation unit and is input from the top of the heavy oil wash T201 together with the circulating heavy oil wash S208 to keep the amount of the heavy oil wash input from the top of the heavy oil wash T201 constant.
The synthesis tail gas output from the top of the heavy oil washing tower T201 is cooled to-20 to-80 ℃ through a synthesis tail gas cooler E202, for example, -24 to-40 ℃, and enters the low-temperature light oil washing tower T203 from the bottom of the tower to be washed by light oil. The light oil lotion is input into a low-temperature light oil washing tower T203 from the top of the tower, the synthetic tail gas after temperature reduction is in countercurrent contact with the low-temperature light oil lotion (the components are C5-C7), so that most of C2 hydrocarbons and all C3-C4 hydrocarbons are washed and removed, other components such as methane, hydrogen, CO and the like are also washed, the operating pressure of the light oil washing tower T203 is 1.5-4.0 MPaG, preferably 2.2-3.0MPaG, and the operating temperature is-20 to-75 ℃, preferably-24 to-40 ℃. The circulating synthesis gas S201 output from the tower top mainly comprises hydrogen and carbon monoxide, and is subjected to pressure reduction and temperature reduction through an expander, then exchanges heat with the synthesis tail gas from the tower top of the heavy oil washing tower in a synthesis tail gas cooler E202, is subjected to temperature increase (reheating) through a circulating synthesis gas reheater E204, and is then sent to an inlet of a synthesis reactor to be used as a circulating synthesis gas, and is used as a raw material together with a fresh synthesis gas to perform a Fischer-Tropsch (FT) reaction or a process for directly preparing olefins (FTO) from the synthesis gas. The synthetic tail gas output from the top of the tower T203 has higher pressure, the cold energy obtained by decompressing and cooling the expander can provide a refrigeration effect for the synthetic tail gas output from the top of the heavy oil washing tower, and the expander can provide a driving force for the desorption gas compressor to reduce the energy consumption of the system by applying work to the outside.
The hydrocarbon-rich light oil wash S207 flowing out from the bottom of the tower mainly comprises the light oil wash and the washed components, and enters the light oil wash regeneration tower T204 for regeneration after exchanging heat with the lean and rich light oil wash heat exchanger E203, the top gas-separated gas S211 output from the top of the regeneration tower T204 is sent to the debutanizer T205, and the regenerated lean oil wash output from the bottom of the tower bottom of the T204 is used as the circulating light oil wash S206 after exchanging heat with the E203. Since a certain portion of the light oil wash loss in the above process needs to be replenished, as shown in fig. 2, a replenished light oil wash S204 is supplied from the heavy hydrocarbon separation unit, and is input from the top of the light oil wash T203 together with the recycled light oil wash S206 to keep the amount of light oil wash input from the top of the light oil wash T203 constant.
Two kinds of desorption gases S210 and S211 from the heavy oil wash regeneration tower T202 and the light oil wash regeneration tower T204 are respectively fed into the debutanizer T205 from different feeding positions. According to one embodiment of the invention, the input location of the stripping gas S210 is closer to the bottom of the column and the input location of the stripping gas S211 is closer to the top of the column. The debutanizer T205 aims to clearly cut C5+ heavier hydrocarbon components and C4-components (namely low-carbon hydrocarbon components) in the analysis gas, so that the load of a subsequent cryogenic separation unit can be reduced, and the C5+ components with high freezing points can be prevented from being frozen and blocked or coked in subsequent cryogenic equipment and pipelines to influence the operation safety of the cryogenic equipment. C5+ hydrocarbons S202 flowing out of the bottom of the debutanizer are sent to a heavy hydrocarbon separation unit for reprocessing, and C4-components S203 extracted from the top of the debutanizer are sent to a subsequent separation unit shown in figure 4 for further separation of low-carbon olefin and alkane products.
Fig. 3 shows another embodiment according to the present invention. In the embodiment shown in fig. 3, the apparatus structural design and operation steps are basically the same as those in fig. 2, except that the medium light oil wash regeneration column T204 and the debutanizer column T205 of fig. 2 are integrated and operated in the same column 204. Specifically, the analysis gas S210 output from the top of the heavy oil wash regenerator T202 is directly sent to the light oil wash regenerator T204 for clear cutting of C4-C5 +. This design is directed to the case where the hydrocarbon content of the hydrocarbon components contained in the synthesis off-gas is extremely low, for example, C8+ hydrocarbons, and in this case, even if these heavy hydrocarbons remain in the light oil wash, the light oil wash quality can be ensured by the operation of recovering a small amount of light oil wash and sending it to the heavy hydrocarbon separation unit for treatment.
Specifically, in the embodiment shown in fig. 3, the synthesis tail gas S100 obtained after passing through the synthesis reaction unit and the pretreatment unit mainly contains C2-C4 olefins, C1-C5 alkanes, a certain amount of C5+ hydrocarbons, hydrogen and carbon monoxide, the synthesis tail gas S100 enters the heavy oil washing tower T201 from the bottom of the tower, at the same time, the heavy oil washing agent S208 (having a composition of C9-C18, preferably C9-C13) is fed into the heavy oil washing tower T201 from the top of the tower, the two streams are contacted in a counter-current manner, and almost all the C5+ hydrocarbons in the synthesis tail gas S100 are removed by washing with heavy oil, and part of H is washed out at the same time 2 CO, C1-C4 alkanes and C2-C4 alkenes. The bottom hydrocarbon-rich heavy oil wash S209 flowing out from the bottom of the column mainly contains the heavy oil wash and the above-mentioned components to be washed out, and almost all the C5+ hydrocarbons are removed from the stream discharged from the top of the column, so that the ratio of C2 to C4 olefins is remarkably increased. According to one embodiment of the invention, the heavy oil wash column is operated at a pressure of 1.5 to 4.0MPaG, preferably 2.2 to 3.0MPaG, and at a temperature of 0 to 50 deg.C, for example 20 to 40 deg.C.
In the embodiment shown in fig. 3, the bottom hydrocarbon-rich heavy oil wash S209 is compared with the circulating heavy oil wash S208 output from the heavy oil wash regenerator T202 (since it has removed the target hydrocarbons in the regenerator T202, this S208 is also referred to herein as a lean oil wash compared to the "hydrocarbon-rich" wash, that is, in this application, the terms circulating heavy oil wash S208 and lean oil wash are used interchangeably) after heat exchange in the lean heavy oil wash heat exchanger E201, and then enters the heavy oil wash regenerator T202, and the T202 overhead gas solution S210 mainly contains components separated from the heavy oil wash and may also contain a certain amount of heavy oil (for example, the wash may contain hydrogen, carbon monoxide, a few C1-C4 alkanes, a few C2-C4 olefins, C5+ hydrocarbons, etc.) which enters the wash regenerator T204, and the regenerated lean oil wash output from the bottom of the T202 is used as the circulating heavy oil wash S208 after heat exchange in E201. Since a certain portion of the heavy oil wash loss in the above process needs to be replenished, as shown in fig. 3, a replenished heavy oil wash S205 is supplied from the heavy hydrocarbon separation unit and is input from the top of the heavy oil wash T201 together with the circulating heavy oil wash S208 to keep the amount of the heavy oil wash input from the top of the heavy oil wash T201 constant.
The synthesis tail gas output from the top of the heavy oil washing tower T201 is cooled to-20 to-80 ℃ by a synthesis tail gas cooler E202, for example, -24 to-40 ℃, and enters a low-temperature light oil washing tower T203 from the bottom of the tower to be washed by light oil. The light oil lotion is input into a low-temperature light oil washing tower T203 from the top of the tower, the synthetic tail gas after temperature reduction is in countercurrent contact with the low-temperature light oil lotion (the components are C5-C7), so that most of C2 hydrocarbons and all C3-C4 hydrocarbons are washed and removed, other components such as methane, hydrogen, CO and the like are also eluted, the operating pressure of the light oil washing tower T203 is 1.5-4.0 MPaG, preferably 2.2-3.0MPaG, and the operating temperature is-20 to-75 ℃, preferably-24 to-40 ℃. The circulating synthesis gas S201 output from the tower top mainly comprises hydrogen and carbon monoxide, and is subjected to pressure reduction and temperature reduction through an expander, then exchanges heat with the synthesis tail gas from the tower top of the heavy oil washing tower in a synthesis tail gas cooler E202, is subjected to temperature increase (reheating) through a circulating synthesis gas reheater E204, and is then sent to an inlet of a synthesis reactor to be used as a circulating synthesis gas, and is used as a raw material together with a fresh synthesis gas to perform a Fischer-Tropsch (FT) reaction or a process for directly preparing olefins (FTO) from the synthesis gas. The synthetic tail gas output from the top of the tower T203 has higher pressure, the cold energy obtained by decompressing and cooling the expander can provide a refrigeration effect for the synthetic tail gas output from the top of the heavy oil washing tower, and the expander can provide a driving force for the desorption gas compressor K301 by applying work to the outside so as to reduce the energy consumption of the system.
For some cases, light hydrocarbons in the synthesis tail gas S100 are mainly C2-C6 hydrocarbons with extremely low C8+ hydrocarbon content, and the C5-C7 light hydrocarbons can be used as light oil lotion, so that the light oil lotion regeneration tower and the debutanizer are combined into a whole. When the light oil lotion regeneration tower T204 is regenerated, only C4-components are cut out and sent to a subsequent separation unit as an overhead material flow S203 for product separation, most of the lean oil lotion extracted from the tower bottom is used as the circulating light oil lotion S206, and a small part of the heavy hydrocarbon-containing light oil lotion S202-2 is extracted and sent to a heavy hydrocarbon separation unit for reprocessing, so that the quality stability of the light oil lotion can be guaranteed. Since a certain portion of the light oil wash loss in the above process needs to be replenished, as shown in fig. 3, a replenished light oil wash S204 is supplied from the heavy hydrocarbon separation unit, and is input from the top of the light oil wash T203 together with the recycled light oil wash S206 to keep the amount of light oil wash input from the top of the light oil wash T203 constant.
The next step is to subject the mixture mainly containing C2-C4 olefins and H to a subsequent cryogenic separation step 2 CO and S203 (resolving C4-components) of C1-C4 alkanes. Fig. 4 shows a flow chart of the separation of S203 according to an embodiment of the invention.
According to one embodiment of the invention, the top gas phase of the depropanizer T301 is subjected to four-stage condensation and two-stage separation operations. By this mode of operation, the subsequent demethanizer load can be significantly reduced and the adverse effect on the C2-C3 hydrocarbon recovery is minimized.
As shown in fig. 4, the desorption gas S203 produced in the previous step is introduced into a desorption gas compressor K301 (1 to 3 stages) to be pressurized to 1.1 to 5.0MPaG, for example, 1.5 to 2MPaG, more preferably 1.6 to 1.8MPaG, and then the pressurized desorption gas S301 is sent to a depropanizer T301 to remove C4 components (butene and butane) from the desorption gas S301. C3-light components are extracted from the top of the depropanizing tower T301, and C4 components are extracted from the bottom of the depropanizing tower and are sent to a butene tower T302. The butene tower T302 is used for clearly cutting butene and butane, a polymer grade butene product S302 is extracted from the tower top, and a butane product S303 is extracted from the tower bottom. The overhead gas phase C3-fraction of the depropanizer T301 is passed through a compressor (4 stages) to 2-8MPaG, preferably 2.5-5.0MPag, more preferably 2.8-4.0MPaG, and then through a first condenser E301 (wherein a first condensing temperature is employed, for example-20 to-60 ℃, preferably-30 to-50 ℃, more preferably-35 to-40 ℃), a second condenser E302 (wherein a second condensing temperature is employed, which is lower than the first condensing temperature, for example-50 to-100 ℃, preferably-60 to-90 ℃, more preferably-70 to-80 ℃), a first separator V301, a third condenser E303 (wherein a third condensing temperature is employed, which is lower than the second condensing temperature, for example-80 to-130 ℃, preferably-90 to-120 ℃, more preferably-95 to-110 ℃), a condenser E304 (wherein a fourth condensing temperature is employed, which is lower than the third condensing temperature, for example-110 to-130 ℃, preferably-90 to-120 ℃, more preferably-95 to-110 ℃), a fourth condensing temperature is employed, and a fourth condensing temperature is preferably-120 to-140 ℃ and a fourth stage separator E304.
The liquid phase components of the first-stage separator V301 and the second-stage separator V302 are respectively fed into the demethanizer T303 from different feeding positions, and the gas phase S312 at the top of the demethanizer T303 and the gas phase S311 of the second-stage separator are merged and then are taken as fuel gas S304 to be sent out of the system. According to this embodiment of the present invention, the S312, S311, and S304 are mainly separated components other than C2 and C3, such as methane, hydrogen, CO, and a very small amount of C2, etc. The produced material flow at the bottom of the demethanizer T303 is a mixture of C2-C3 hydrocarbons, which are sent to a deethanizer T304 for clear cutting of C2 and C3 components. Feeding the gas phase at the top of the deethanizer T304 into an ethylene tower T306 for clear cutting of ethylene and ethane to obtain a polymer grade ethylene product S305 and an ethane product S306; the liquid phase product at the bottom of the deethanizer T304 is sent to a propylene tower T305 for clear cutting of propylene and propane to obtain polymer grade propylene product S307 and propane product S308.
Without wishing to be bound by any particular theory, the present invention has the following advantages over the prior art:
the invention adopts the special combination of the process steps, and can realize higher recovery rate of the low-carbon olefin with lower investment and less energy consumption. The method avoids the adverse effect of specific components on the cryogenic separation unit, obviously reduces the processing load and energy consumption of the cryogenic separation unit while obtaining high recovery rate of the low-carbon olefin, and reduces the equipment scale of the cryogenic separation. The specific combination of the invention is suitable for light hydrocarbon recovery and separation in technical routes of coal-to-olefin, fischer-Tropsch synthesis tail gas or synthesis gas to olefin and the like, which cannot be realized by the prior art.
Examples
Preferred embodiments of the present invention are specifically exemplified in the following examples, but it should be understood that the scope of the present invention is not limited thereto. In the following inventive and comparative examples of the present application, the product lower hydrocarbon fraction of syngas direct to olefins (FTO) was used as the feedstock, and the syngas direct to olefins (FTO) was carried out according to the process conditions of the literature [ Cobalt carbide nanoparticles for direct production of lower olefins from syngas (nare 2016,538, 84-87) ].
Example 1:
the apparatus of example 1 was constructed in the manner shown in fig. 2 and 4. Firstly, the equipment shown in fig. 2 is operated, and the synthetic tail gas S100 enters a two-stage oil washing light hydrocarbon recovery unit after passing through a synthesis and pretreatment unit, wherein the working conditions and the components are shown in table 1. The synthetic tail gas S100 enters a heavy oil washing tower T201 to be in countercurrent contact with heavy oil washing agent (with the components of C9-C13) from the top of the tower, and C5+ hydrocarbons and part of H in the synthetic tail gas are removed 2 CO and C1-C4 components, the top pressure of a heavy oil washing tower is 2.85MPaG, and the temperature is 40 ℃. The bottom hydrocarbon-rich heavy oil lotion S209 and the bottom lean oil lotion from the heavy oil lotion regeneration tower T202 enter the heavy oil lotion regeneration tower T202 after heat exchange in a lean and rich heavy oil lotion heat exchanger E201, the top desorption gas S210 of the T202 enters the debutanizer T205, and the lean oil lotion regenerated from the bottom of the T202 is used as a circulating heavy oil lotion S208 after heat exchange in the E201. The lost heavy oil wash is replenished by the heavy oil wash S205 from the heavy hydrocarbon separation unit such that the heavy oil wash supply remains substantially constant.
The synthetic tail gas from the top of the heavy oil washing tower T201 is cooled to-40 ℃ by a synthetic tail gas cooler E202, and enters a low-temperature light oil washing tower T203 for light oil washing. The cooled synthetic tail gas is in countercurrent contact with low-temperature light oil lotion (with the components of C5-C7) to remove C2-C4 and part of H 2 CO and CH 4 And the pressure of the top of the light oil washing tower T203 is 2.8MPaG, and the temperature is-40 ℃. The produced light oil lotion S207 rich in hydrocarbon at the bottom of the tower exchanges heat with the heat exchanger E203 rich in light oil lotion at the bottom of the tower, the light oil lotion enters a light oil lotion regeneration tower T204 for regeneration, the top of the tower is analyzed gas S211 and sent to a debutanizer T205, and the regenerated light oil lotion at the bottom of the T204 is used as a circulating light oil lotion S206 after exchanging heat with the E203. The make-up light oil wash S204 comes from a heavy hydrocarbon separation unit as the oil wash entrainment losses need to be made up.
Two kinds of desorption gas S2010 and S211 from the heavy oil lotion regeneration tower T202 and the light oil lotion regeneration tower T204 are respectively sent into the debutanizer T205 from different feeding positions, and C5+ heavier hydrocarbon components in the desorption gas are cut off. C5+ hydrocarbons S202 extracted from the bottom of the debutanizer are sent to a heavy hydrocarbon separation unit for reprocessing, and C4-components S203 extracted from the top of the debutanizer are sent to a subsequent cryogenic separation unit for product separation.
The subsequent operation is repeated in the equipment shown in FIG. 4, the desorption gas S203 enters a desorption gas compressor K301 (1-3 stages) to be pressurized to 1.6MPaG, and the desorption gas is sent to a depropanizer T301 to remove C4 components (butylene and butane) in the desorption gas. C3-light components are extracted from the top of the depropanizing tower T301, and C4 components are extracted from the bottom of the depropanizing tower and are sent to a butene tower T302. The butene tower T302 is used for clearly cutting butene and butane, a polymer grade butene product S302 is produced at the top of the tower, and a butane product S303 is produced at the top of the tower. The C3-component of the gas phase at the top of the depropanizer is pressurized by a compressor (4 stages) for 3.0MPaG, and then passes through a first-stage condenser E301 (the condensation temperature is minus 37 ℃), a second-stage condenser E302 (the condensation temperature is minus 72 ℃), a first-stage separator V301, a third-stage condenser E303 (the condensation temperature is minus 108 ℃), a fourth-stage condenser E304 (the condensation temperature is minus 133 ℃) and a second-stage separator V302 respectively.
The liquid phase components of the first-stage separator V301 and the second-stage separator V302 are respectively fed into the demethanizer T303 from different feeding positions, and the gas phase S312 at the top of the demethanizer T303 and the gas phase S311 of the second-stage separator are merged and then are sent out of the system as fuel gas S304. C2-C3 extracted from the bottom of the demethanizer T303 are sent to a deethanizer T304 for clear cutting of C2 and C3 components. Feeding the gas phase at the top of the deethanizer T304 into an ethylene tower T306 for clear cutting of ethylene and ethane to obtain a polymer grade ethylene product S305 and an ethane product S306; the liquid phase product at the bottom of the deethanizer T304 is sent to a propylene tower T305 for clear cutting of propylene and propane to obtain polymer grade propylene product S307 and propane product S308.
The components of each stream are listed in table 1 below.
TABLE 1 materials data sheet
As can be seen from the data in the material flow table 1, the ethylene recovery rate reaches 93.48%, the propylene recovery rate reaches 99.86%, and the butene recovery rate reaches 99.68%. In addition, the purity of ethylene, propylene and butylene products can exceed 99.9 percent.
Example 2:
the apparatus of example 2 was constructed in the manner shown in fig. 3 and 4. The plant shown in FIG. 3 was first operated and the synthesis off-gas S100 obtained via the synthesis and pretreatment unit was reprocessed in the plant shown in FIG. 3, the composition of which is shown in Table 1. Specifically, the synthetic tail gas S100 enters a heavy oil washing tower T201 to be in countercurrent contact with heavy oil washing agent (with the components of C9-C13) from the top of the tower, and C5+ hydrocarbons and part of H in the synthetic tail gas are removed 2 CO, C1-C4 components, heavy oil tower top pressure 2.85MPaG, and temperature 40 ℃. The bottom hydrocarbon-rich heavy oil wash S209 and the lean oil wash from the bottom of the heavy oil wash regeneration tower T202 enter the heavy oil wash regeneration tower T202 after heat exchange in the lean and rich heavy oil wash heat exchanger E201 (the tower top pressure is 0.38 MPaG), the top resolved gas S210 of the T202 tower is sent to the light oil wash regeneration tower T204, and the regenerated lean oil wash from the bottom of the T202 tower is used as the circulating heavy oil wash S208 after heat exchange in the lean and rich light oil wash heat exchanger E201. The depleted heavy oil wash is replenished by a replenishment heavy oil wash S205 from the heavy hydrocarbon separation unit to maintain a substantially constant heavy oil wash loading.
The synthetic tail gas discharged from the top of the heavy oil washing tower T201 is cooled to-40 ℃ by a synthetic tail gas cooler E202, and enters a low-temperature light oil washing tower T203 for light oil washing. The cooled synthetic tail gas is in countercurrent contact with low-temperature light oil lotion (with the components of C5-C7) to remove C2-C4 and part of H 2 CO and the like, the pressure of the top of the light oil scrubber T203 is 2.8MPaG, and the temperature is-40 ℃. The bottom rich hydrocarbon light oil wash S207 exchanges heat with the lean rich light oil wash heat exchanger E203 and then enters a light oil wash regeneration tower T204 (the pressure at the top of the tower is 0.32 MPaG) for regeneration. For the loss of light oil wash, make-up is done using the make-up light oil wash S204 from the heavy hydrocarbon separation unit so that the supply of light oil wash remains substantially constant.
The subsequent operation is repeated in the apparatus shown in FIG. 4, and the stripping gas S203 enters a stripping gas compressor K301 (1-3 stages) to be pressurized to 1.6MPaG, and is sent to a depropanizer T301 to remove C4 components (butylene and butane) in the stripping gas. C3-light components are extracted from the top of the depropanizing tower T301, and C4 components are extracted from the bottom of the depropanizing tower and are sent to a butene tower T302. The butene tower T302 is used for clearly cutting butene and butane, a polymer grade butene product S302 is produced at the tower top, and a butane product S303 is produced at the tower top. The C3-component of the gas phase at the top of the depropanizer is pressurized by a compressor (4 stages) for 3.0MPaG, and then passes through a first-stage condenser E301 (the condensation temperature is minus 37 ℃), a second-stage condenser E302 (the condensation temperature is minus 72 ℃), a first-stage separator V301, a third-stage condenser E303 (the condensation temperature is minus 108 ℃), a fourth-stage condenser E304 (the condensation temperature is minus 133 ℃) and a second-stage separator V302 respectively.
Liquid phase components of the first-stage separator V301 and the second-stage separator V302 are respectively fed into the demethanizer T303 from different feeding positions, and a gas phase S312 at the top of the demethanizer T303 and a gas phase S311 of the second-stage separator are merged and then are fed out of the system as a fuel gas S304. C2-C3 extracted from the bottom of the demethanizer T303 are sent to a deethanizer T304 for clear cutting of C2 and C3 components. Feeding the gas phase at the top of the deethanizer T304 into an ethylene tower T306 for clear cutting of ethylene and ethane to obtain a polymer grade ethylene product S305 and an ethane product S306; the liquid phase product at the bottom of the deethanizer T304 is sent to a propylene tower T305 for the clear cutting of propylene and propane to obtain a polymer grade propylene product S307 and a propane product S308.
TABLE 2 Logistics data sheet
As can be seen from the data in the material flow table 2, the ethylene recovery rate reaches 93.52%, the propylene recovery rate reaches 99.86%, and the butene recovery rate reaches 99.67%. In addition, the purity of ethylene, propylene and butylene products can exceed 99.9 percent.
Claims (4)
1. A process for purifying a lower olefin containing stream, the process comprising:
step (i): providing a feed stream comprising C2 to C4 olefins;
step (ii): conveying the raw material flow into a heavy oil washing tower, and washing the raw material flow by using a heavy oil lotion in the heavy oil washing tower to obtain a hydrocarbon-rich heavy oil lotion flow and a gas phase flow at the top of the heavy oil washing tower, wherein the heavy oil lotion is C9-C18 hydrocarbon, and the pressure in the heavy oil washing tower is 1.5-4.0 MPaG;
step (iii): cooling the gas phase flow at the top of the heavy oil washing tower, conveying the cooled gas phase flow into a light oil washing tower, and washing the gas phase flow at the top of the heavy oil washing tower by using a low-temperature light oil lotion to obtain a hydrocarbon-rich light oil lotion flow and a light oil washing tower top gas phase flow, wherein the light oil lotion is C5-C7 hydrocarbon, the pressure in the light oil washing tower is 1.5-4.0 MPaG, and the temperature is-20-75 ℃;
step (iv): separating the hydrocarbon-rich heavy oil wash stream to yield a circulating heavy oil wash and a first product stream comprising C2-C8 olefins;
step (v): separating the hydrocarbon-rich light oil wash stream to obtain a recycle light oil wash and a second product stream comprising C2-C4 olefins;
step (vi): separating the first and second product streams to obtain C2-C4 olefins in a mixed or separate state;
the circulating heavy oil wash and optionally fresh makeup heavy oil wash are conveyed to the heavy oil wash column; the recycled light oil wash and optionally fresh makeup light oil wash are delivered to the light oil wash column.
2. The method of claim 1, wherein in step (vi), the first and second products are each independently or after being combined, treated sequentially with:
(a) Separating the C4-components from the C5+ components in a debutanizer column;
(b) Pressurizing the C4-component obtained in the step (a), conveying the pressurized C4-component to a depropanizer, separating the C3-component from the C4-component, and conveying the C4-component to a butene tower to separate butane and butene;
(c) Subjecting the C3-component obtained in step (b) to multistage condensation and multistage separation to separate ethylene, propylene, methane, ethane and propane therefrom.
3. The method of claim 1, wherein the method employs an apparatus for purifying a lower olefin containing stream, the apparatus comprising a heavy oil wash column, a low temperature light oil wash column, a heavy oil wash regenerator, and a light oil wash regenerator, and further comprising at least one of the following: a debutanizer, a depropanizer, a butene tower, a multi-stage condensing and separating device, a demethanizer, a deethanizer, a propylene tower, and an ethylene tower.
4. The method of claim 1, wherein the method employs equipment for purifying a low carbon olefin-containing stream, the equipment comprises a heavy oil washing tower, a low-temperature light oil washing tower, a heavy oil lotion regeneration tower and a light oil lotion regeneration tower, and further comprises the following connection modes:
the raw material flow supply device is connected to the inlet of the heavy oil washing tower through a pipeline, the outlet of the top of the heavy oil washing tower is connected with the inlet of the synthesis tail gas cooler, and the outlet of the synthesis tail gas cooler is connected with the inlet of the low-temperature light oil washing tower;
the gas phase outlet of the low-temperature light oil washing tower is connected with the inlet of an expansion machine, the outlet of the expansion machine is connected with the other inlet of the synthesis gas cooler, the other outlet of the synthesis gas cooler is connected with the inlet of a synthesis tail gas reheater, and the outlet of the reheater is connected with the inlet of a synthesis reactor;
the outlet of the heavy oil washing tower kettle is connected with the inlet of a lean and rich heavy oil lotion heat exchanger, the outlet of the lean and rich heavy oil lotion heat exchanger is connected with the inlet of a heavy oil lotion regeneration tower, the outlet of the heavy oil lotion regeneration tower top is connected with the inlet of the debutanizer bottom, the outlet of the heavy oil lotion tower kettle is connected with the other inlet of the lean and rich heavy oil lotion heat exchanger, and the other outlet of the lean and rich heavy oil lotion heat exchanger is connected with the inlet of the heavy oil washing tower top;
the outlet of the tower bottom of the low-temperature light oil washing tower is connected with the inlet of a heat exchanger for the lean and rich light oil lotion, the outlet of the heat exchanger for the lean and rich light oil lotion is connected with the inlet of a light oil lotion regeneration tower, the gas phase outlet of the light oil lotion regeneration tower is connected with the inlet at the upper part of the debutanizer, the outlet of the tower bottom is connected with the other inlet of the heat exchanger for the lean and rich light oil lotion, and the other outlet of the lean and rich light oil lotion is connected with the inlet at the top of the low-temperature light oil washing tower;
the gas phase outlet of the debutanizer is connected with the inlet of a desorption gas compressor, the outlet of the compressor is connected with the inlet of the depropanizer, and the kettle outlet of the depropanizer is connected with the inlet of a butene tower;
the outlet of the tower top of the depropanizing tower is connected with the inlet of the compressor between stages, the outlet of the compressor tail section is connected with the inlet of a first-stage condenser, the outlet of the first-stage condenser is connected with the inlet of a second-stage condenser, the outlet of the second-stage condenser is connected with the inlet of a first-stage separator, the gas phase outlet of the first-stage separator is connected with the inlet of a third-stage condenser, the outlet of the third-stage condenser is connected with the inlet of a fourth-stage condenser, and the outlet of the fourth-stage condenser is connected with the inlet of the second-stage separator;
1. the liquid phase outlet of the second-stage separator is respectively connected with the upper inlet and the lower inlet of the demethanizer, the gas phase outlet of the demethanizer and the gas phase outlet of the second-stage separator are connected with a fuel gas pipeline, the liquid phase outlet of the demethanizer is connected with the inlet of the deethanizer, the gas phase outlet of the deethanizer is connected with the inlet of the ethylene tower, and the liquid phase outlet of the deethanizer is connected with the inlet of the propylene tower.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4401450A (en) * | 1980-09-11 | 1983-08-30 | Linde Aktiengesellschaft | Economic recovery of ethylene and/or propylene from low concentration feeds |
| EP1887072A1 (en) * | 2006-08-10 | 2008-02-13 | Shell Internationale Researchmaatschappij B.V. | a process for the treatment of fischer-tropsch tail gas |
| CN101559320A (en) * | 2009-04-15 | 2009-10-21 | 上海惠生化工工程有限公司 | Separation method of Fischer-Tropsch synthesis gas by combining rectification and solvent absorption |
| CN105733647A (en) * | 2014-12-09 | 2016-07-06 | 中科合成油工程股份有限公司 | Method for recovering liquefied petroleum gas from Fischer-Tropsch synthesis tail gas |
| CN110156557A (en) * | 2019-06-11 | 2019-08-23 | 东营亿鑫化工有限公司 | A kind of recovery method of petrochemical industry output gas |
| CN210560161U (en) * | 2019-09-19 | 2020-05-19 | 北京恒泰洁能科技有限公司 | Fischer-Tropsch synthesis tail gas recycling device |
-
2020
- 2020-11-02 CN CN202011203219.3A patent/CN112174766B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4401450A (en) * | 1980-09-11 | 1983-08-30 | Linde Aktiengesellschaft | Economic recovery of ethylene and/or propylene from low concentration feeds |
| EP1887072A1 (en) * | 2006-08-10 | 2008-02-13 | Shell Internationale Researchmaatschappij B.V. | a process for the treatment of fischer-tropsch tail gas |
| CN101559320A (en) * | 2009-04-15 | 2009-10-21 | 上海惠生化工工程有限公司 | Separation method of Fischer-Tropsch synthesis gas by combining rectification and solvent absorption |
| CN105733647A (en) * | 2014-12-09 | 2016-07-06 | 中科合成油工程股份有限公司 | Method for recovering liquefied petroleum gas from Fischer-Tropsch synthesis tail gas |
| CN110156557A (en) * | 2019-06-11 | 2019-08-23 | 东营亿鑫化工有限公司 | A kind of recovery method of petrochemical industry output gas |
| CN210560161U (en) * | 2019-09-19 | 2020-05-19 | 北京恒泰洁能科技有限公司 | Fischer-Tropsch synthesis tail gas recycling device |
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