CN113387769A - Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method - Google Patents
Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method Download PDFInfo
- Publication number
- CN113387769A CN113387769A CN202110293935.3A CN202110293935A CN113387769A CN 113387769 A CN113387769 A CN 113387769A CN 202110293935 A CN202110293935 A CN 202110293935A CN 113387769 A CN113387769 A CN 113387769A
- Authority
- CN
- China
- Prior art keywords
- tower
- dry gas
- absorption
- propane
- refinery
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/11—Purification; Separation; Use of additives by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
- C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
- C10L3/08—Production of synthetic natural gas
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Water Supply & Treatment (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention provides a separation method for recovering C1, C2 and C3 in saturated dry gas of a refinery by a combined absorption method, which comprises the following steps: s1, gradually compressing the refinery saturated dry gas to 3-4.5 MPag through a gas compressor, removing impurities through an impurity removal facility, cooling to about 15 ℃ through a cooler, and entering an absorption tower; s2, the absorption tower adopts liquid-phase propane or propane-rich C3 fraction as an absorbent, and the absorbent enters the absorption tower from the top of the tower to absorb components of C2 and above C2 in saturated dry gas; feeding the tower bottom material of the absorption tower to a desorption tower; the invention provides a combined absorption method which adopts propane or C3 fraction rich in propane as an absorbent and adopts toluene or benzene, xylene and industrial hexane as a reabsorber to separate C1, C2 and C3 in saturated dry gas of a refinery, and effectively solves the problems of high energy consumption, large investment, low recovery rate, dry gas non-dryness and the like in the separation process of C1, C2 and C3 in the saturated dry gas of the existing refinery.
Description
Technical Field
The invention relates to a separation method for recovering C1, C2 and C3, in particular to a separation method for recovering C1, C2 and C3 in saturated dry gas of a refinery by a combined absorption method.
Background
The saturated dry gas of the refinery is mainly from primary processing and secondary processing of crude oil, such as by-product gas in the processes of atmospheric and vacuum distillation, hydrocracking, reforming, disproportionation and the like, and mainly comprises components of hydrogen, methane, ethane, propane and the like. At present, most of the saturated dry gas of refineries is directly used as industrial or civil fuel, which causes serious waste of resources. Ethane and propane can be used as raw materials of an ethylene cracking device for producing ethylene and propylene, so that the cost of ethylene cracking raw materials can be effectively reduced, and the economic benefit of enterprises is improved.
At present, the separation method of saturated dry gas in a refinery mainly comprises a cryogenic separation method, an intermediate cooling oil absorption method, a pressure swing adsorption method, a shallow cooling oil absorption method and the like, and various methods have respective characteristics. The cryogenic separation method has high recovery rate and mature process, but has large equipment investment and higher energy consumption; the intercooled oil absorption method has low investment and strong adaptability, but has lower recovery rate, large circulation amount and loss of the absorbent and higher energy consumption; the pressure swing adsorption has low energy consumption, simple operation, large occupied area, poor absorption effect, low product purity and low recovery rate.
Patent publication No. CN106609161A proposes a method for separating saturated dry gas of refinery, which adopts C4 as absorbent, and absorbs C2 fraction and heavier components in the saturated dry gas after compression and cooling in a main absorption tower, the bottom stream of the main absorption tower is sent to a desorption tower, and the top of the desorption tower obtains recovered C2 concentrated gas. The pressure of the absorption tower is about 3.0-4.5 MPag, the temperature of the top of the absorption tower is about 5-25 ℃, and the temperature of the bottom of the absorption tower is 100-160 ℃. The temperature of the top of the desorption tower is 55-65 ℃, and the temperature of the bottom of the desorption tower is 100-160 ℃. The method is provided with a reabsorption tower and a stabilization tower, wherein stabilized gasoline is used as an absorbent to absorb a C4 absorbent carried out from gas at the top of a main absorption tower, rich absorption oil enters the stabilization tower, the temperature at the top of the stabilization tower is 40-80 ℃, and the temperature at the bottom of the stabilization tower is 150-200 ℃. The recovery rate of the C2 in the method is about 97%, the total recovery rate of the C2 and the C3 is about 94%, but the circulating amount and the loss amount of the absorbent are large, the temperatures of the bottoms of the absorption tower, the desorption tower and the stabilizing tower are high, and the energy consumption is relatively high.
The patent publication No. CN104560194A proposes a recovery system and a recovery method of saturated dry gas in a refinery plant, wherein the method adopts carbon four or carbon five as an absorbent, a condensate stripping tower is arranged, condensate between sections of a compressor is sent to the condensate stripping tower, and a product after stripping is directly sent to an ethylene device cracking furnace. The method is additionally provided with a reabsorption tower, and the reabsorption agent is gasoline. The total recovery rate of C2 and C3 in the method is about 96 percent, but the circulating amount and the loss amount of the absorbent are large, the temperatures of the bottoms of the absorption tower and the desorption tower are high, and the energy consumption is high.
Patent publication No. CN109553504A proposes a method and a device for recovering refinery saturated dry gas by adopting a shallow cold oil absorption technology, wherein C4 is adopted as an absorbent, the temperature of the top of an absorption tower is about 5-25 ℃, and the temperature of the bottom of the absorption tower is 100-160 ℃. The temperature of the top of the desorption tower is 55-65 ℃, the temperature of the bottom of the desorption tower is 100-160 ℃, most of the liquid phase at the bottom of the desorption tower is used as a circulating absorbent to return to the absorption tower, and the small part of the liquid phase is sent to a gasoline stabilizing tower for treatment. The reabsorption tower adopts stable gasoline as an absorbent to absorb the C4 absorbent carried out from the gas at the top of the main absorption tower, and the rich absorption oil enters the stabilization tower, wherein the temperature at the top of the stabilization tower is 40-80 ℃, and the temperature at the bottom of the stabilization tower is 120-150 ℃. The recovery rate of the C2 is about 98 percent, the total recovery rate of the C2 and the C3 is about 95 percent, but the circulating amount and the loss amount of the absorbent are large, the temperatures of the bottoms of the absorption tower, the desorption tower and the stabilizing tower are high, the energy consumption is relatively high, and the hydrogen cannot be recovered.
In summary, the current refinery gas recycling mainly aims at catalytic dry gas, and the recycling of saturated dry gas is less studied. The existing process for separating C2 and C3 from saturated dry gas has the problems of high energy consumption, large equipment scale, large investment, low recovery rate of C2 and C3, dry gas and the like.
Disclosure of Invention
The invention aims to provide a separation method for recovering C1, C2 and C3 in saturated dry gas of a refinery by a combined absorption method, so as to solve the problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
a combined absorption method for separating C1, C2 and C3 from saturated dry gas of a refinery comprises the following steps:
s1, gradually compressing the refinery saturated dry gas to 3-4.5 MPag through a gas compressor, removing impurities through an impurity removal facility, cooling to about 15 ℃ through a cooler, and entering an absorption tower;
s2, the absorption tower adopts liquid-phase propane or propane-rich C3 fraction as an absorbent, and the absorbent enters the absorption tower from the top of the tower to absorb components of C2 and above C2 in saturated dry gas; feeding the tower bottom material of the absorption tower to a desorption tower;
s3, enabling the tower top gas phase of the absorption tower to enter a reabsorption tower, enabling the reabsorption tower to adopt liquid-phase methylbenzene or benzene, dimethylbenzene and industrial hexane as reabsorbers to absorb C2 and C3 components carried out by the tower top gas phase of the absorption tower, enabling the tower top gas of the reabsorption tower to be used as dry gas to be merged into a fuel gas pipe network, and feeding the tower bottom materials of the reabsorption tower into a reabsorption tower;
s4, condensing the gas phase at the top of the re-desorption tower, pumping the condensate rich in propane, returning the condensate to the absorption tower, and circulating the liquid phase at the bottom of the re-desorption tower as a re-absorbent to return to the top of the re-absorption tower;
s5, feeding the material at the bottom of the absorption tower into a desorption tower, obtaining an ethane and propane mixed component at the top of the desorption tower, and feeding the C3+ component at the bottom of the desorption tower into a depropanizing tower for continuous separation;
s6, separating the top of the depropanizing tower to obtain high-purity propane, wherein one part of the high-purity propane is used as a circulating absorbent and returns to the absorption tower, and the other part of the high-purity propane is used as a propane product separation device; the C4+ liquid phase obtained at the bottom of the tower is sent to a subsequent device for treatment.
As a further scheme of the invention: in step S1, the refinery saturated dry gas is compressed by 3-4 stages.
As a further scheme of the invention: 20-70 layers of theoretical plates of the absorption tower, 10-40 layers of feeding positions, 3-4.5 MPag of tower top pressure, 10-25 ℃ of tower top temperature and 60-95 ℃ of tower bottom temperature; the absorption tower is provided with a plurality of middle sections for heat extraction and reflux.
As a further scheme of the invention: 15-70 layers of theoretical plates of the reabsorption tower, 5-40 layers of feeding positions, 3-4.5 MPag of tower top pressure and 10-35 ℃ of tower top temperature; the reabsorption tower is provided with a plurality of middle section heat extraction reflux streams.
As a further scheme of the invention: the reabsorption tower comprises 15-60 layers of theoretical plates and 5-30 layers of feeding positions, wherein the pressure at the top of the tower is 0.6-1 MPag, the temperature at the top of the tower is 10-25 ℃, and the temperature at the bottom of the tower is 200-230 ℃.
As a further scheme of the invention: the desorption tower comprises 20-60 layers of theoretical plates and 10-40 layers of feeding positions, the pressure at the top of the tower is 1.5-3 MPag, the temperature at the top of the tower is 15-30 ℃, and the temperature at the bottom of the tower is 60-85 ℃.
As a further scheme of the invention: the depropanizer comprises 20-70 layers of theoretical plates and 10-50 layers of feeding positions, wherein the pressure at the top of the depropanizer is 0.6-1.5 MPag, the temperature at the top of the depropanizer is 20-45 ℃, and the temperature at the bottom of the depropanizer is 60-100 ℃.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention provides a separation method for recovering C1, C2 and C3 in saturated dry gas by a combined absorption method, aiming at solving the problems of high energy consumption, large investment, low recovery rate, no dry gas and the like in the separation process of C1, C2 and C3 in the saturated dry gas of the existing refinery. The method takes propane as an absorbent and toluene as a reabsorber, can greatly improve the recovery rate of ethane and propane, and solves the problems of high energy consumption, large investment, low recovery rate, dry gas non-drying and the like in the separation process of the saturated dry gas C1, C2 and C3 in the existing refinery.
2. The invention provides a combined absorption method which adopts propane or C3 fraction rich in propane as an absorbent and adopts toluene or benzene, xylene and industrial hexane as reabsorbers to separate C1, C2 and C3 in saturated dry gas of a refinery.
3. The invention takes propane or C3 fraction rich in propane as absorbent, has better effect of absorbing C2 and small dosage of the absorbent. And the propane or the C3 fraction rich in propane is produced by the device, so that the operation cost is reduced.
4. The invention takes toluene (or benzene, xylene and industrial hexane) as the reabsorber which is produced by the refinery, thereby reducing the operation cost.
5. The invention adopts toluene (or benzene, xylene and industrial hexane) as the reabsorber, and has good effect of absorbing C3, little C3 component carried by methane fuel gas, small recycling amount of the reabsorber, and the carrying amount of heavy components in dry gas is not more than 0.2mol percent.
6. The present invention adopts propane or C3 fraction rich in propane as absorbent and toluene (or benzene, xylene and industrial hexane) as re-absorbent, and has ethane and propane recovering rate up to 98%, relatively small circulating amount and leakage loss of the absorbent, basically no need of supplementary absorbent and low power consumption.
7. The tower bottoms of the absorption tower, the desorption tower and the depropanization tower have lower temperature, and the heat source of a reboiler at the tower bottom can adopt hot water, low-temperature process material waste heat and the like, so that the energy consumption is lower.
Drawings
FIG. 1 is a schematic structural diagram of a separation method for recovering C1, C2 and C3 from saturated dry gas of a refinery by a combined absorption method.
In the figure: 1. a gas compressor; 2. impurity removal facilities; 3. a gas cooler; 4. an absorption tower; 5. a reabsorption tower; 6. then desorbing the tower; 7. a desorption tower; 8. a depropanizer.
Detailed Description
The technical solution of the present patent will be described in further detail with reference to the following embodiments.
Referring to fig. 1, a method for separating C1, C2 and C3 from refinery saturated dry gas by a combined absorption method includes the following steps:
s1, gradually compressing the refinery saturated dry gas to 3-4.5 MPag through a gas compressor 1, removing impurities through an impurity removal facility 2, cooling to about 15 ℃ through a cooler 3, and allowing the gas to enter an absorption tower 4;
s2, the absorption tower 4 adopts liquid-phase propane or propane-rich C3 fraction as an absorbent, and the absorbent enters the absorption tower 4 from the top of the tower to absorb components with the contents of C2 and above C2 in saturated dry gas; the tower bottom material of the absorption tower 4 is sent to a desorption tower 7;
s3, enabling the tower top gas phase of the absorption tower 4 to enter a reabsorption tower 5, enabling the reabsorption tower 5 to adopt liquid-phase methylbenzene or benzene, dimethylbenzene and industrial hexane as reabsorbers to absorb C2 and C3 components carried out by the tower top gas phase of the absorption tower 4, enabling the tower top gas of the reabsorption tower 5 to be used as dry gas to be merged into a fuel gas pipe network, and enabling the tower bottom material of the reabsorption tower 5 to be sent into a reabsorption tower 6;
s4, condensing the gas phase at the top of the re-desorption tower 6, pumping the condensate rich in propane, returning the condensate to the absorption tower 4, and circulating the liquid phase at the bottom of the re-desorption tower 6 serving as a re-absorbent to return to the top of the re-absorption tower 5;
s5, feeding the tower bottom materials of the absorption tower 4 into a desorption tower 7, obtaining ethane and propane mixed components at the tower top of the desorption tower 7, and feeding the C3+ components at the tower bottom of the desorption tower 7 into a depropanization tower 8 for continuous separation;
s6, separating the top of the depropanizing tower 8 to obtain high-purity propane, wherein one part of the high-purity propane is used as a circulating absorbent and returns to the absorption tower 4, and the other part of the high-purity propane is used as a propane product separation device; the C4+ liquid phase obtained at the bottom of the tower is sent to a subsequent device for treatment.
In step S1, the saturated dry gas in the refinery is compressed by 3-4 stages.
Further, the absorption tower 4 comprises 20-70 layers of theoretical plates and 10-40 layers of feeding positions, the pressure at the top of the tower is 3-4.5 MPag, the temperature at the top of the tower is 10-25 ℃, and the temperature at the bottom of the tower is 60-95 ℃; the absorption tower 4 is provided with a plurality of middle heat-taking reflux streams.
Further, the reabsorption tower 5 comprises 15-70 layers of theoretical plates and 5-40 layers of feeding positions, the tower top pressure is 3-4.5 MPag, and the tower top temperature is 10-35 ℃; the reabsorption tower 5 is provided with a plurality of mid-section heat extraction reflux streams.
Further, the reabsorption tower 6 comprises 15-60 layers of theoretical plates and 5-30 layers of feeding positions, the pressure at the top of the tower is 0.6-1 MPag, the temperature at the top of the tower is 10-25 ℃, and the temperature at the bottom of the tower is 200-230 ℃.
Furthermore, the desorption tower 7 has 20-60 layers of theoretical plates and 10-40 layers of feeding positions, the pressure at the top of the tower is 1.5-3 MPag, the temperature at the top of the tower is 15-30 ℃, and the temperature at the bottom of the tower is 60-85 ℃.
Further, the depropanizer 8 has 20-70 layers of theoretical plates and 10-50 layers of feeding positions, the pressure at the top of the tower is 0.6-1.5 MPag, the temperature at the top of the tower is 20-45 ℃, and the temperature at the bottom of the tower is 60-100 ℃.
In this example, propane was used as the absorbent, toluene was used as the reabsorber, and the composition of the saturated dry gas, the absorbent and the reabsorber is shown in the following table:
| saturated dry gas | Absorbent agent | Reabsorbing agent | |
| Mass flow rate t/h | 86.99 | 200 | 260 |
| Molar composition (mol%) | |||
| Hydrogen gas | 56.12 | ||
| Nitrogen gas | 4.25 | ||
| Carbon monoxide | 0.10 | ||
| Oxygen gas | 0.04 | ||
| Carbon dioxide | 0.64 | ||
| Methane | 18.01 | ||
| Ethylene | 0.38 | ||
| Ethane (III) | 13.77 | 0.15 | |
| Hydrogen sulfide | - | ||
| Propylene (PA) | 0.02 | 0.07 | |
| Propane | 3.97 | 99.77 | |
| C4 | 1.95 | 0.08 | |
| C5 | 0.47 | ||
| C6+ | 0.26 | ||
| Toluene | - | 100 |
The saturated dry gas of the refinery comes from other devices of the refinery, enters the gas compressor 1, and is compressed in four sections to increase the pressure to 4.2 MPag. The pressurized saturated dry gas passes through an impurity removal facility 2, is cooled to about 15 ℃ by a gas cooler 3, and enters an absorption tower 4. The absorption tower 4 takes propane as an absorbent, enters from the top of the tower, and absorbs C2 and above components in the gas. Wherein, the number of theoretical plates of the absorption tower 4 is preferably 50 layers, the operation pressure is 4MPag, the tower top temperature is 14.5 ℃, the tower bottom temperature is 85.6 ℃, and the absorption tower 4 is provided with a plurality of middle section heat-taking reflux.
The gas at the top of the absorption tower 4 enters a reabsorption tower 5, the theoretical plate number of the reabsorption tower 5 is preferably 35 layers, the operation pressure is 3.5MPag, the temperature at the top of the tower is 17 ℃, and the reabsorption tower 5 is provided with a plurality of middle-section heat-taking reflux; the rich absorption liquid at the bottom of the absorption tower 4 enters a desorption tower 7 for separation. The reabsorption tower 5 adopts toluene as a reabsorption agent to absorb C2 and C3 components brought out by the gas phase at the top of the absorption tower 4, methane-hydrogen fuel gas (dry gas) obtained at the top of the reabsorption tower 5 is merged into a fuel gas pipe network, and materials at the bottom of the reabsorption tower 5 are sent into a re-desorption tower 6. The number of theoretical plates of the re-desorption tower 6 is preferably 20, the operating pressure is 0.8MPag, the temperature at the top of the tower is 22 ℃, the temperature at the bottom of the tower is 216 ℃, the condensate rich in propane and obtained by separation at the top of the re-desorption tower 6 is pressurized by a pump and then returns to the absorption tower 4, and the toluene at the bottom of the re-desorption tower 6 is used as a reabsorber for cooling and pressurizing and then is circulated and returned to the top of the reabsorber 5.
The theoretical plate number of the desorption column 7 is preferably 30 layers, the operating pressure is 2.3MPag, the temperature at the top of the column is about 22 ℃ and the temperature at the bottom of the column is 69 ℃. The mixed component of ethane and propane is separated from the top of the desorption tower 7 and is sent to a downstream ethylene cracking device, wherein the propane amount is basically equal to the propane amount in the saturated dry gas of the refinery; and C3+ components at the bottom of the tower enter a depropanizer 8 for further separation. The number of theoretical plates of the depropanizer 8 is preferably 40, the operating pressure is 0.8MPag, the temperature at the top of the tower is about 22.7 ℃, the temperature at the bottom of the tower is 79.8 ℃, high-purity propane separated from the top of the depropanizer 8 is totally used as a circulating absorbent and returns to the absorption tower in the embodiment, and no propane product is produced; the C4+ product 27 from the bottom of the depropanizer 8 is sent to a subsequent plant for processing.
The isolated products are shown in the following table:
in the present example, the ethane recovery rate was 99.68%, the propane recovery rate was 97.54%, the C2 and C3 recovery rates were 99.04%, and the entrainment of heavy components in the methane fuel gas was less than 0.2 mol%.
The working principle of the invention is as follows: the content of C2 and C3 in the saturated dry gas of the refinery is about 20mol percent, and the balance is hydrogen, methane, water, impurities, components with more than C4 and the like. Wherein, the gas product of the saturated dry gas contains about 30-60 mol% of hydrogen, about 15-20 mol% of methane, about 10-15 mol% of ethane and about 2-5 mol% of propane. The invention is particularly limited to the absorbent which is propane or a C3 fraction rich in propane and the reabsorber which is toluene or benzene, xylene, industrial hexane or other components.
The specific process flow is as follows:
saturated dry gas from a refinery enters a gas compressor 1 at the temperature of 40 ℃, is compressed to 3-4.5 MPag through three-stage or four-stage compression, is desulfurized and subjected to other impurity removal, is cooled to 15 ℃ through refrigerant water, and enters an absorption tower 4. The absorption tower 4 takes propane or C3 fraction rich in propane as an absorbent, the gas phase material at the top of the absorption tower 4 enters a reabsorption tower 5, and the rich absorption liquid at the bottom of the absorption tower 4 enters a desorption tower 7 for separation. The reabsorption tower 5 adopts toluene as a reabsorption agent to absorb part of components C2 and C3 which are carried by the non-condensed steam at the top of the absorption tower 4, the dry methane-hydrogen fuel gas obtained at the top of the reabsorption tower 5 enters a fuel gas pipe network, and the liquid phase at the bottom of the reabsorption tower 5 is sent to a reabsorption tower 6.
The condensate rich in propane obtained by the separation at the top of the re-desorption tower 6 is pressurized by a pump and then returns to the absorption tower 4, and the toluene at the bottom of the re-desorption tower 6 is used as a re-absorbent and circularly returns to the top of the re-absorption tower 5. The mixed components of ethane and propane separated from the top of the desorption tower 7 can also be separated to obtain high-purity ethane, and the C3+ components at the bottom of the desorption tower enter a depropanizing tower 8 for further separation. A part of the high-purity propane separated from the tower top of the depropanizing tower 8 is used as a circulating absorbent to return to the absorption tower 4, and a part of the high-purity propane is used as a product outlet device; the C4+ product from the bottom of the depropanizer 8 is sent to a subsequent plant for processing.
Although the preferred embodiments of the present patent have been described in detail, the present patent is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present patent within the knowledge of those skilled in the art.
Claims (7)
1. A combined absorption method for separating C1, C2 and C3 from saturated dry gas in a refinery is characterized by comprising the following steps:
s1, gradually compressing the refinery saturated dry gas to 3-4.5 MPag through a gas compressor, removing impurities through an impurity removal facility, cooling to about 15 ℃ through a cooler, and entering an absorption tower;
s2, the absorption tower adopts liquid-phase propane or propane-rich C3 fraction as an absorbent, and the absorbent enters the absorption tower from the top of the tower to absorb components of C2 and above C2 in saturated dry gas; feeding the tower bottom material of the absorption tower to a desorption tower;
s3, enabling the tower top gas phase of the absorption tower to enter a reabsorption tower, enabling the reabsorption tower to adopt liquid-phase methylbenzene or benzene, dimethylbenzene and industrial hexane as reabsorbers to absorb C2 and C3 components carried out by the tower top gas phase of the absorption tower, enabling the tower top gas of the reabsorption tower to be used as dry gas to be merged into a fuel gas pipe network, and feeding the tower bottom materials of the reabsorption tower into a reabsorption tower;
s4, condensing the gas phase at the top of the re-desorption tower, pumping the condensate rich in propane, returning the condensate to the absorption tower, and circulating the liquid phase at the bottom of the re-desorption tower as a re-absorbent to return to the top of the re-absorption tower;
s5, feeding the material at the bottom of the absorption tower into a desorption tower, obtaining an ethane and propane mixed component at the top of the desorption tower, and feeding the C3+ component at the bottom of the desorption tower into a depropanizing tower for continuous separation;
s6, separating the top of the depropanizing tower to obtain high-purity propane, wherein one part of the high-purity propane is used as a circulating absorbent to return to the absorption tower, and the other part of the high-purity propane is used as a propane product to be discharged out of the device; the C4+ liquid phase obtained at the bottom of the tower is sent to a subsequent device for treatment.
2. The combined absorption process for recovering C1, C2 and C3 from refinery saturated dry gas according to claim 1, wherein in step S1, the refinery saturated dry gas is compressed in 3-4 stages.
3. The combined absorption method for separating C1, C2 and C3 from saturated dry gas in a refinery according to claim 1, wherein the absorption tower has 20-70 layers of theoretical plates, 10-40 layers of feeding positions, 3-4.5 MPag of pressure at the top of the tower, 10-25 ℃ of temperature at the top of the tower and 60-95 ℃ of temperature at the bottom of the tower; the absorption tower is provided with a plurality of middle sections for heat extraction and reflux.
4. The combined absorption process for separating C1, C2 and C3 from saturated dry gas in a refinery according to claim 1, wherein the reabsorption tower has 15-70 layers of theoretical plates, 5-40 layers of feeding positions, 3-4.5 MPag of overhead pressure and 10-35 ℃ of overhead temperature; the reabsorption tower is provided with a plurality of middle section heat extraction reflux streams.
5. The combined absorption method for separating C1, C2 and C3 from saturated dry gas in a refinery according to claim 1, wherein the re-desorption tower has 15-60 layers of theoretical plates, 5-30 layers of feeding positions, 0.6-1 MPag of overhead pressure, 10-25 ℃ of overhead temperature and 200-230 ℃ of bottom temperature.
6. The combined absorption method for separating C1, C2 and C3 from refinery saturated dry gas according to claim 1, wherein the desorption tower has 20-60 layers of theoretical plates, 10-40 layers of feeding positions, 1.5-3 MPag of top pressure, 15-30 ℃ of top temperature and 60-85 ℃ of bottom temperature.
7. The combined absorption method for separating C1, C2 and C3 from refinery saturated dry gas according to claim 1, wherein the depropanizer has 20-70 theoretical plates, 10-50 feeding positions, 0.6-1.5 MPag overhead pressure, 20-45 ℃ overhead temperature and 60-100 ℃ bottom temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110293935.3A CN113387769A (en) | 2021-03-19 | 2021-03-19 | Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110293935.3A CN113387769A (en) | 2021-03-19 | 2021-03-19 | Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113387769A true CN113387769A (en) | 2021-09-14 |
Family
ID=77617556
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110293935.3A Withdrawn CN113387769A (en) | 2021-03-19 | 2021-03-19 | Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113387769A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102304010A (en) * | 2011-07-11 | 2012-01-04 | 中国天辰工程有限公司 | Method for separating low carbon olefin mixed gas by rectifying and absorbing |
| CN104419465A (en) * | 2013-09-10 | 2015-03-18 | 中国石油化工股份有限公司 | Dry gas recovery system and dry gas recovery method for refinery plant |
| CN104557384A (en) * | 2013-10-23 | 2015-04-29 | 中国石油化工股份有限公司 | Refinery mixed dry gas recovery system and recovery method |
| CN105273757A (en) * | 2014-07-25 | 2016-01-27 | 中国石油化工股份有限公司 | Method for separating refinery dry gas by NMP absorption |
| CN109678635A (en) * | 2017-10-19 | 2019-04-26 | 中国石油化工股份有限公司 | A kind of utilization method of saturated hydrocarbons cracking gas separating system and rich ethane/propane saturated hydrocarbons |
| CN109912379A (en) * | 2017-12-12 | 2019-06-21 | 中国石油化工股份有限公司 | A kind of oil refinery dry gas separation method and device |
-
2021
- 2021-03-19 CN CN202110293935.3A patent/CN113387769A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102304010A (en) * | 2011-07-11 | 2012-01-04 | 中国天辰工程有限公司 | Method for separating low carbon olefin mixed gas by rectifying and absorbing |
| CN104419465A (en) * | 2013-09-10 | 2015-03-18 | 中国石油化工股份有限公司 | Dry gas recovery system and dry gas recovery method for refinery plant |
| CN104557384A (en) * | 2013-10-23 | 2015-04-29 | 中国石油化工股份有限公司 | Refinery mixed dry gas recovery system and recovery method |
| CN105273757A (en) * | 2014-07-25 | 2016-01-27 | 中国石油化工股份有限公司 | Method for separating refinery dry gas by NMP absorption |
| CN109678635A (en) * | 2017-10-19 | 2019-04-26 | 中国石油化工股份有限公司 | A kind of utilization method of saturated hydrocarbons cracking gas separating system and rich ethane/propane saturated hydrocarbons |
| CN109912379A (en) * | 2017-12-12 | 2019-06-21 | 中国石油化工股份有限公司 | A kind of oil refinery dry gas separation method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109912380B (en) | Pyrolysis gas separation method and device | |
| CN109912379B (en) | Refinery dry gas separation method and device | |
| JP2022509733A (en) | Methods and systems for separating light hydrocarbons | |
| EP4053251A1 (en) | Method and device for recovering c2-c4 components in methane-containing industrial gas | |
| CN113121301B (en) | Recovery method of light hydrocarbon in refinery dry gas | |
| CN112410070B (en) | Energy-saving process and device for recovering carbon dioxide from refinery dry gas | |
| CN105273757B (en) | A kind of method of NMP absorption and separations oil refinery dry gas | |
| CN113354506B (en) | Method for recovering and separating low-carbon hydrocarbons from refinery saturated dry gas by combined absorption | |
| CN111393252B (en) | Light hydrocarbon separation device and method | |
| CN110407658B (en) | Low-energy-consumption cryogenic separation process method for ethane pyrolysis gas | |
| CN111320523B (en) | Method and device for separating ethylene from refinery dry gas | |
| CN113354501B (en) | Separation method for recovering C1, C2 and C3 in catalytic rich gas by combined absorption method | |
| CN113354502B (en) | Method for separating low-carbon hydrocarbon from unsaturated dry gas by combined absorption and recovery | |
| CN111004079A (en) | Separation method and device for preparing ethylene reaction gas through oxidative coupling of methane | |
| CN109748771A (en) | The method for recycling carbon two in oil refinery dry gas | |
| CN112707787B (en) | Pyrolysis gas separation system with purification function and utilization method | |
| CN113387769A (en) | Separation method for recovering C1, C2 and C3 in refinery saturated dry gas by combined absorption method | |
| CN111320522B (en) | Method and device for separating ethylene from refinery dry gas | |
| CN113350974B (en) | H in saturated dry gas2C1, C2 and C3 separation and recovery method | |
| CN112920007A (en) | Catalytic cracking gas separation process and device for producing high-concentration ethylene | |
| CN111238164A (en) | Intercooling separation device and process for catalytic cracking product gas | |
| CN112760130A (en) | Oil-gas separation and recovery device and method | |
| CN112707785B (en) | Pyrolysis gas separation system with cold energy recovery function and separation method | |
| CN105273758B (en) | A kind of method of DMF absorption and separations oil refinery dry gas | |
| CN113355135A (en) | Separation method of saturated dry gas of refinery plant |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20210914 |
|
| WW01 | Invention patent application withdrawn after publication |