CN106403499B - It is a kind of to wash process coproduction high concentration liquid CO using low-temp methanol2Method - Google Patents

It is a kind of to wash process coproduction high concentration liquid CO using low-temp methanol2Method Download PDF

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CN106403499B
CN106403499B CN201610791573.XA CN201610791573A CN106403499B CN 106403499 B CN106403499 B CN 106403499B CN 201610791573 A CN201610791573 A CN 201610791573A CN 106403499 B CN106403499 B CN 106403499B
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tower
liquid
gas
methanol
phase
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CN106403499A (en
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宫万福
闫兵海
吕建宁
侯宁
黄科
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Wison Engineering Ltd
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Wison Engineering Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/06—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation
    • F25J3/063—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream
    • F25J3/067—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by partial condensation characterised by the separated product stream separation of carbon dioxide
    • 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
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • C10L3/101—Removal of contaminants
    • C10L3/102—Removal of contaminants of acid contaminants
    • C10L3/103—Sulfur containing contaminants
    • 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
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • C10L3/101—Removal of contaminants
    • C10L3/102—Removal of contaminants of acid contaminants
    • C10L3/104—Carbon dioxide
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/151—Reduction of greenhouse gas [GHG] emissions, e.g. CO2

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Separation By Absorption (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Process coproduction high concentration liquid CO is washed using low-temp methanol the present invention relates to a kind of2Method, including high concentration liquid CO2Production process and low-temp methanol wash process, the high concentration liquid CO2Production process is the following steps are included: (A) richness CO2Unstripped gas dehydration, cooling, the first knockout drum of feeding；(B) liquid phase stream of the first gas-liquid separation pot bottom condensation is sent into CO2Product purifying column purification；The low-temp methanol washes process the following steps are included: low temperature poor methanol absorbing carbon dioxide at the top of (C) decarbonizing tower；(D) in desulfurizing tower, rich methanol handles sulfur-bearing gaseous mixture as absorbent；(E) in methane stripping tower, the rich methanol that tower bottom gas phase air lift enters from tower top is to recycle methane gas；(F)H2S concentration tower and methanol hot recycling tower remove sour gas and regenerated methanol recycle through vacuum flashing and hot recycling.Compared with prior art, the present invention is with low energy consumption, liquid CO2The advantages that product design is high, raw material availability is high.

Description

It is a kind of to wash process coproduction high concentration liquid CO using low-temp methanol2Method
Technical field
The present invention relates to field of gas purification, are suitable for rich carbonated thick methane gas more particularly, to one kind and exist The method of coproduction part high concentration liquid carbon dioxide during using low-temp methanol washing process decarburization.
Background technique
Carbon dioxide is widely used in the industries such as chemical industry, machinery, food, agricultural, medicine, tobacco, fire-fighting, not only purposes Extensively, demand also increasingly increases, and development and application prospect is wide.In the carbon dioxide production in China, machine is mostly concentrated on The non-chemical industry such as tool, metallurgy, production scale is small, and coordinative composition of equipments is poor, causes that product quality is low, energy consumption is big, city's field energy Power is small.
Produce liquid CO2Unstripped gas source mainly have the CO generated during high-temperature calcination lime stone2, Alcohol Production The CO generated in fermentation process2And the rich CO generated in synthetic ammonia tailgas, coal gas decarbonizing process2Gas etc., CO in these gases2 Concentration is although relatively high, but there is the features such as pressure is low, impurity component is complicated, either high-pressure process, senior middle school's low-pressure process, low temperature Low-pressure process produces liquid CO 2, and the above-mentioned raw materials gas processes such as purified will clean, dry, compress are handled, and gas pressure The energy consumption accounting of compression process is again larger, causes production liquid CO2The plant investment and energy consumption of product are higher.
The coal of solid is obtained synthesis gas through gasifier system by Modern Coal-based Chemical, then using synthesis gas as waste methanol, natural The products such as gas, synthetic oil, with the difference of gasification technology, by the pressure for the synthesis gas obtained that gasifies be generally 3.5MPa (G)~ 6.5MPa(G).Mostly use desulfurization and decarburization device by the sulfide and CO in synthesis gas in current coal chemical engineering equipment2Separation, The extremely low high concentration CO of pressure is obtained in desulfurization and decarburization device2, this portion gas or direct emission or also need further Desulfurization, purification, pressurization, cooling produce liquid CO2.In Modern Coal-based Chemical industrial chain, there are high pressure, richness are carbonated Intermediate products, while Modern Coal-based Chemical unit scale is all very big, as can by the CO in the intermediate products gas of this partial high pressure2Gas Liquid CO is made in partial liquefaction2Product, product scale is also very huge, and can save conventional liq CO2Gas in production process Compression, cooling energy consumption.The low-temp methanol washing process sour gas as disclosed in Chinese patent ZL 201010599841.0 removes work Skill, when low-temp methanol washes absorbing carbon dioxide and Mathanol regenerating in this technique, energy consumption is very high.Therefore, if a kind of knot can be developed The technique that low-temp methanol is washed with produces high concentration liquid carbon dioxide is closed, the energy in technical process by combining the two is mutual It mends, is bound to that the energy consumption that the two separately carries out can be greatly reduced.
Summary of the invention
Low-temp methanol is utilized it is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide a kind of Wash technique coproduction high concentration liquid CO2Method.
The purpose of the present invention can be achieved through the following technical solutions:
It is a kind of to wash process coproduction high concentration liquid CO using low-temp methanol2Method, including high concentration liquid CO2Produce work Sequence and low-temp methanol wash process,
The high concentration liquid CO2Production process the following steps are included:
(A) richness CO2It is cooling after unstripped gas dehydration, it is re-fed into the first knockout drum；
(B) liquid phase stream of the first gas-liquid separation pot bottom condensation is sent into CO2Product purifying column purification, CO2Product mentions Pure tower bottom is refining to obtain high-purity liquid CO2, what top gaseous phase exported after compressing pressure-raising with the first gas-liquid separation tank top Gaseous stream is sent into decarburization tower bottom together as carbonaceous gas；
The low-temp methanol wash process the following steps are included:
(C) the low temperature poor methanol at the top of decarbonizing tower absorbs the carbon dioxide from the carbonaceous gas that decarburization tower bottom enters, It is exported as rich methanol from decarburization tower bottom, wherein a part enters methane stripper-overhead, and another part enters desulfurization tower top Portion is discharged after the heat exchange of decarbonizing tower top gaseous phase；
(D) enter the rich methanol at the top of desulfurizing tower as absorbent, processing enters pretreated from desulfurization tower bottom Sulfur-bearing gaseous mixture, wherein desulfurizing tower tower bottom liquid phase rich methanol enters H2S concentration tower, after the heat exchange of desulfurizing tower top gaseous phase a part Discharge, another part enter methane stripping tower tower bottom；
(E) the part rich methanol of decarburization tower bottom enters methane gas stripper overhead after depressurizing, then through methane stripping tower bottom The part top gaseous phase air lift from desulfurizing tower at place generates methane rich gas phase in methane gas stripper overhead and is sent into methane makeup It sets, H is entered after methane stripping tower tower bottom liquid phase processor2S concentration tower；
(F) enter H from the tower bottom liquid phase that desulfurizing tower and methane stripping tower are discharged2Vacuum flashing in S concentration tower, and use nitrogen Air lift, the tail gas emptying that tower top generates, tower bottom are rich in H2The liquid phase of S enters methanol hot recycling tower, and after hot recycling, methanol heat is again Raw column overhead is precipitated sour gas and sends out battery limit (BL), and the absorbent poor methanol after tower bottom regeneration, which is sent to decarbonizing tower, to be recycled.
High concentration liquid CO2In production process:
The rich CO2The dewatered cooling of unstripped gas is divided into precooling and two step of deep condensation, in precooling, rich CO2It is former Expect gas a part and CO2Product purifies the high-purity liquid CO of tower bottom output2Heat exchange pre-cooling, another part with from decarbonizing tower and H2The top gaseous phase of S concentration tower discharge, which exchanges heat, to be pre-chilled, then two parts richness CO2Unstripped gas carries out deep condensation together.
CO2The high-purity liquid CO of product purifying column tower bottom output2It is divided into three parts, wherein a part and richness CO2Raw material CO is returned after gas heat exchange2Product purifying column tower reactor, a part and richness CO2It is vented after unstripped gas heat exchange, remaining a part is as highly concentrated Spend liquid CO2Output of products.
In step (D): the pretreatment of sulfur-bearing gaseous mixture are as follows: third knockout drum top gas phase and the 4th knockout drum Top gas phase mix after mixing compression with sulfur-bearing conversion gas, liquid methanol, then with the part tower of the discharge at the top of the desulfurizing tower After top gas mutually exchanges heat, into the second knockout drum, the top sulfur-bearing gaseous mixture isolated enters desulfurizing tower processing, bottom liquid phases It is sent into subsequent methanol-water separating；
Desulfurizing tower tower bottom liquid phase enters H2It is also pre-processed before S concentration tower, specifically:
Desulfurizing tower tower bottom liquid phase is cooling by heat exchange, depressurizes, and into third knockout drum, isolates top gas phase through pressing Desulfurizing tower processing is returned to after contracting, bottom liquid phases enter H2S concentration tower.
In step (E) methane stripping tower:
Top gaseous phase, which first exchanges heat, precools the top gaseous phase that is discharged from methanol hot recycling tower, then send to methanation device；
Tower bottom liquid phase, which first exchanges heat, to be cooled down, depressurizes, and is re-fed into the 4th knockout drum, is isolated top gas phase and return after compression Desulfurizing tower processing is returned, bottom liquid phases enter H2S concentration tower.
Step (F) H2In S concentration tower:
Side output par, c H2S concentration material is changed with the tower bottom liquid phase being discharged from decarbonizing tower and methanol hot recycling tower respectively After heat, H is returned again to2It is handled in S concentration tower；
Tower bottom H2S enters methanol hot recycling tower after liquid phase material and the heat exchange of methanol hot recycling tower tower bottom liquid phase is concentrated.
In step (F) methanol hot recycling tower:
Top gaseous phase enters the 5th knockout drum after condensing, and isolates top gas phase and sends out battery limit (BL), bottom liquid phases are returned Return methanol hot recycling tower.
Rich CO2Water content after unstripped gas dehydration is less than 100ppm (v/v%).Rich co2 unstripped gas dehydration Method, including but not limited to using molecular sieve, activated alumina, silica gel, glycol solution and ionic liquid absorption etc., dehydration system System can be arranged using a series of or multi-series.
Rich CO2Unstripped gas condensation after enter the first knockout drum when stream temperature be 0 DEG C~-56 DEG C, preferably -5 DEG C~-40 DEG C.
CO2The tower top pressure of product purifying column is 0.5MPa (G)~6MPa (G), and temperature is -15 DEG C~-56 DEG C, tower bottom pressure Power is 0.5MPa (G)~6MPa (G), and temperature is 25 DEG C~-50 DEG C.
Compared with prior art, the invention has the following advantages that
(1) by combining low-temp methanol to wash in process and high concentration liquid carbon dioxide production process between different material The difference of temperature, raw material etc., so that in the entire system, the mutual conversion of emission and raw material may be implemented between different towers, Also the case where exchange that heat or cooling capacity may be implemented between each stock logistics, compared to two processes are run independently of each other, energy consumption It is substantially reduced with material loss, environmental protection and energy saving greatly enhances.
(2) coproduction high concentration liquid CO2Concentration can reach 99.9% or more food-grade, product is on a grand scale, especially It is suitable for applying in Modern Coal-based Chemical device, the fabulous sulfide for compensating for desulfurization and decarburization device etc. and low-pressure high concentration CO2Direct emission and the defect for causing environmental pollution and material waste.
Detailed description of the invention
Fig. 1 is the structural diagram of the present invention.
Specific embodiment
The present invention is described in detail with specific embodiment below in conjunction with the accompanying drawings.
Embodiment 1
As shown in Figure 1, purifying two different unstripped gas using low-temp methanol washing process, both unstripped gas are respectively to come CO is rich in from methanation device from the sulfur-bearing conversion gas 1 of upstream converting means2, not sulfur-bearing thick methane feed gas 10, The coproduction part high concentration liquid carbon dioxide product through the invention during using low-temp methanol washing process desulfurization and decarburization.
The temperature of unstripped gas 10 is 40 DEG C in the present embodiment, pressure 5.5MPa (G), flow 180kNm3/ h, unstripped gas 10 The concentration of middle each component is respectively CO2: 66.7%, CH4: 32.7%, H2: 0.16%, N2: 0.24%, Ar:0.2%, the present invention It is achieved by the steps of:
(1) unstripped gas 10 is after dewatering system 11 is dry, and water content is less than 20ppm in unstripped gas 10；
(2) is through the dewatered partial raw gas 1 (being controlled by regulating valve 7 12) of step (1), through heat exchanger a14 ( To logistics 15), heat exchanger b16 be cooled to -15 DEG C of feeding knockout drum a18；
(3) through heat exchanger c30, is changed through the dewatered partial raw gas 2 29 (being controlled by regulating valve 8 28) of step (1) Hot device d31 is cooling (obtaining logistics 32), is sent into heat exchanger b16 through regulating valve 1, is cooled to -15 DEG C of logistics 17, is sent into gas Liquid knockout drum a18；At this point, there are also the dewatered other part unstripped gas three controlled by regulating valve 6 35 directly and heat exchanger After e36 heat exchange, it is sent into knockout drum a18；
(4) gaseous stream 19 at the top of knockout drum a18 is sent into 42 bottom of decarbonizing tower, the bottom knockout drum a18 The liquid CO 2 material 20 of condensation is sent into CO after pressure reducing valve a21 is further depressurized222 purification of product purifying column, In CO222 bottom of product purifying column obtains the liquid carbon dioxide product 95.2t/h of purification, pressure 3.0MPa (G), liquid Body CO2Concentration is greater than 99.9%, sends out product 39 through regulating valve 2 38；
(5).CO222 top gaseous phase 25 of product purifying column is fed together de- after compressor a26 pressurization with gaseous stream 19 42 bottom of carbon tower further absorbs the carbon dioxide in mixed gas 27 using the low temperature poor methanol stream 93 at 42 top of decarbonizing tower, Gas 43 after decarburization is sent out after heat exchanger a14 recycles cooling capacity；
(6) rich methanol 47 of 42 bottom of decarbonizing tower is sent into methane stripping tower 48, methane air lift after pressure reducing valve b87 decompression Top gaseous phase is sent into compressor b50 after heat exchanger m52 recycles cooling capacity, and pressurized gas 51 is sent out.Methane stripping tower 48 Tower bottom rich methanol is cooling through heat exchanger h53, after pressure reducing valve c91 decompression, be sent into knockout drum d54；
(7) rich methanol 44 of 42 bottom of decarbonizing tower, after being sent into heat exchanger f46 and heat exchanger g49 cooling by pump 1, It is sent into the tower top of desulfurizing tower 6, the absorbent as sulfur-bearing gaseous mixture 5 uses.The tower bottom rich methanol 10 of desulfurizing tower 6 is through heat exchanger Knockout drum c55 is sent into after i56 is cooling, pressure reducing valve d92 is depressurized；
(8) knockout drum d54 bottom liquid phases 81 and knockout drum c55 bottom liquid phases 82 are sent into subsequent H2S concentration Tower 58；
H2In S concentration tower 58, gas is mentioned using nitrogen 85, side discharging 73 is being changed through 4 59 conveying of pump, a part of material 75 Cooling capacity is provided at hot device g49, another part material 74 provides cooling capacity at heat exchanger o60, then integrated side mixture 72 returns H2S concentration tower 58；Top discharge 49 empties after heat exchanger a14 provides cooling capacity as tail gas 86；Bottom discharge 80 is through pump 2 61 It is sent into heat exchanger k62 after exchanging heat and obtains cooling material 78, after pressure reducing valve g90 decompression, into methanol hot recycling tower 63；
In methanol hot recycling tower 63, top gas phase 71 is successively cooling through heat exchanger m52, heat exchanger n66, is sent into gas-liquid separation In tank e67, isolated top gas phase 69 is vented, and bottom liquid phases 68 return to methanol hot recycling tower 63；63 bottom of methanol hot recycling tower Equipped with circuit is boiled again, heat exchanger l64 is equipped on circuit boiling again.Regenerated poor methanol 79 passes through pump 3 65, a part of poor methanol 70 output is ready for use, and another part poor methanol 76 successively (it is poor to obtain low temperature through heat exchanger k62 (obtaining logistics 77), heat exchanger o60 Methanol stream 93) it is cooling after, input decarbonizing tower 42；
(9) gas phase 83 of knockout drum d54 and knockout drum c55 through compressor c57 pressurization after with sulfur-bearing conversion gas 1 mixing, while a small amount of liquid methanol 84 is sprayed into, knockout drum b3, gas-liquid point are further sent into after heat exchanger j2 is cooling It is sent into subsequent methanol-water separating from tank b3 bottom liquid phases 4, the gas phase on the top knockout drum b3 is sent into desulfurizing tower 6；
(10) desulfurization top gaseous phase 1 is sent out after heat exchanger j2 heat exchange as product 9, and desulfurization top gaseous phase 27 passes through The bottom of pressure reducing valve e88 feeding methane stripping tower 48.
In the present embodiment, the moisture in unstripped gas, dewatered raw material are absorbed using activated alumina in the step (1) Gas water content is less than 20ppm (v/v%).
The present embodiment, heat exchanger b16 is arranged one in the step (2), step (3), and the cooling capacity of heat exchanger b16 is by propylene Refrigerant provides, and the temperature by adjusting the flow control logistics 17 of cryogen is -15 DEG C.
The present embodiment, the CO in the step (4), step (5)20.5~3 MPa of tower top pressure of product purifying column 22 (G), temperature is -15~-40 DEG C.
The present embodiment, 0.5~3MPa of tower bottom pressure (G) of the CO2 product purifying column 22 in the step (4), temperature is- 1~-10 DEG C.
In the present embodiment, using the method and apparatus coproduction of the invention liquid carbon dioxide product of 135t/h, reduce Low-temp methanol washes the corresponding energy consumption of absorbing carbon dioxide and Mathanol regenerating, while if using common process production 135t/h, The liquid carbon dioxide product of pressure 3.0MPa (G) at least needs the gas phase carbon dioxide by 0.3MPa (G) to be pressurized to 3.0MPa (G), 40 DEG C while using recirculated cooling water by unstripped gas are cooled to, recycling refrigerant to provide cooling capacity keeps gas phase carbon dioxide cold It is solidifying, and the energy that this process needs to consume is as follows:
Compressor horsepower, kw Recirculated cooling water, t/h Cooling load, kw
Energy consumption 5420 520 11337
Embodiment 2
As shown in Figure 1, purifying two different unstripped gas using low-temp methanol washing process, both unstripped gas are respectively to come CO is rich in from methanation device from the sulfur-bearing conversion gas 1 of upstream converting means2, not sulfur-bearing thick methane gas 10, in benefit With coproduction part high concentration liquid carbon dioxide product through the invention during low-temp methanol washing process desulfurization and decarburization.
The temperature of unstripped gas 10 is 40 DEG C in the present embodiment, pressure 3.1MPa (G), flow 162kNm3/ h, unstripped gas 10 The concentration of middle each component is respectively CO2: 68%, CH4: 31.33%, H2: 0.18%, N2: 0.35%, Ar:0.14%, the present invention It is achieved by the steps of:
(1) unstripped gas 10 is after dewatering system 11 is dry, and water content is less than 20ppm in unstripped gas 10；
(2) is cooled to -30 DEG C through heat exchanger a14, heat exchanger b16 through the dewatered partial raw gas 1 of step (1) It is sent into knockout drum a18；
(3) is through the dewatered partial raw gas 2 29 of step (1), through heat exchanger c30, heat exchanger d31 cooling, through adjusting Valve 1 is sent into heat exchanger b16, is cooled to -30 DEG C of logistics 17, is sent into knockout drum a18；
(4) gaseous stream 19 at the top of knockout drum a18 is sent into 42 bottom of decarbonizing tower, the bottom knockout drum a18 The liquid CO 2 20 of condensation is sent into CO after pressure reducing valve a21 is further depressurized222 purification of product purifying column, in CO2 22 bottom of product purifying column obtains the liquid CO of purification2Product 126t/h, pressure 1.5MPa (G), liquid CO2Concentration is greater than 99.9%, it is sent out through regulating valve 2 38.
The present embodiment, 1.5~2.5MPa of tower top pressure (G) of the CO2 product purifying column 22 in the step (4), temperature It is -15~-45 DEG C, 1.5~2.5MPa of tower bottom pressure (G), temperature is -1~-20 DEG C.
In the present embodiment, using the method and apparatus coproduction of the invention liquid carbon dioxide product of 126t/h, reduce Low-temp methanol washes absorbing carbon dioxide and the regenerated corresponding energy consumption of methanol solution, while if being produced using common process The liquid carbon dioxide product of 126t/h, pressure 1.5MPa (G) at least need for the gas phase carbon dioxide of 0.3MPa (G) to be pressurized To 1.5MPa (G), unstripped gas is cooled to 40 DEG C using recirculated cooling water, recycling refrigerant to provide cooling capacity makes gas phase titanium dioxide Carbon condensation, and the energy that this process needs to consume is as follows:
Compressor horsepower, kw Recirculated cooling water, t/h Cooling load, kw
Energy consumption 3270 315 12662
Embodiment 3
As shown in Figure 1, purifying two different unstripped gas using low-temp methanol washing process, both unstripped gas are respectively to come From the sulfur-bearing conversion gas 1 of upstream converting means with from methanation device rich in CO2, the thick methane gas 10 of not sulfur-bearing, pass through Method and apparatus of the invention, can flexible modulation liquid carbon dioxide product yield.
The temperature of unstripped gas 10 is 40 DEG C in the present embodiment, pressure 5.5MPa (G), flow 180kNm3/ h, unstripped gas 10 The concentration of middle each component is respectively CO2: 66.7%, CH4: 32.7%, H2: 0.16%, N2: 0.24%, Ar:0.2%, the present invention It is achieved by the steps of coproduction liquid carbon dioxide product:
(1) unstripped gas 10 is after dewatering system 11 is dry, and water content is less than 20ppm in unstripped gas 10；
(2) is cooled to -15 DEG C through heat exchanger a14, heat exchanger b16 through the dewatered partial raw gas 1 of step (1) It is sent into knockout drum a18；
(3) is through the dewatered partial raw gas 2 29 of step (1), through heat exchanger c30, heat exchanger d31 cooling, through adjusting Valve 1 is sent into heat exchanger b16, is cooled to -5 DEG C of logistics 17, is sent into knockout drum a18；
(4) gaseous stream 19 at the top of knockout drum a18 is sent into 42 bottom of decarbonizing tower, the bottom knockout drum a18 The liquid CO 2 20 of condensation is sent into CO after pressure reducing valve a21 is further depressurized222 purification of product purifying column, in CO2 22 bottom of product purifying column obtains the liquid carbon dioxide product 41t/h of purification, liquid CO2Concentration is greater than 99.9%, warp Regulating valve 38 is sent out；
The present embodiment, the CO in the step (4)21.5~3MPa of tower top pressure (G) of product purifying column 22, temperature be- 15~-40 DEG C, 1.5~3MPa of tower bottom pressure (G), temperature is -1~-10 DEG C.
In the present embodiment, using the method and apparatus coproduction of the invention liquid carbon dioxide product of 41t/h, reduce Low-temp methanol washes absorbing carbon dioxide and the regenerated corresponding energy consumption of methanol solution, while if using common process production 41t/h, The liquid carbon dioxide product of pressure 3.0MPa (G) at least needs the gas phase carbon dioxide by 0.3MPa (G) to be pressurized to 3.0MPa (G), unstripped gas is cooled to 40 DEG C using recirculated cooling water, recycling refrigerant to provide cooling capacity condenses gas phase carbon dioxide, And the energy that this process needs to consume is as follows:
Compressor horsepower, kw Recirculated cooling water, t/h Cooling load, kw
Energy consumption 1626 157 3402
It is achieved by the steps of using the present invention when not needing coproduction liquid carbon dioxide product:
(1) unstripped gas 10 is after dewatering system 11 is dry, and water content is less than 20ppm in unstripped gas 10；
(2) is cooled to -15 DEG C through heat exchanger a14, heat exchanger b16 through the dewatered partial raw gas 1 of step (1) It is sent into knockout drum a18；
(3) is through the dewatered partial raw gas 2 29 of step (1), through heat exchanger c30, heat exchanger d31 cooling, through adjusting Valve 2 34 is sent into knockout drum a18；
(4) gaseous stream 19 at the top of knockout drum a18 is sent into 42 bottom of decarbonizing tower, the bottom knockout drum a18 The liquid CO 2 20 of condensation is sent into CO after pressure reducing valve a21 is further depressurized222 purification of product purifying column, in CO2 22 bottom of product purifying column obtains the liquid carbon dioxide product of purification；
(5) is decreased or turned off the aperture of regulating valve 3 38, reduces the yield of liquid carbon dioxide product, while increasing tune The aperture of valve 4 37 and regulating valve 5 40 is saved, and passes sequentially through heat exchanger d31 and heat exchanger e36 withdrawal liquid carbon dioxide gasification The cooling capacity released in the process, atmospheric carbon dioxide 41 are vented in home.
The above description of the embodiments is intended to facilitate ordinary skill in the art to understand and use the invention. Person skilled in the art obviously easily can make various modifications to these embodiments, and described herein general Principle is applied in other embodiments without having to go through creative labor.Therefore, the present invention is not limited to the above embodiments, ability Field technique personnel announcement according to the present invention, improvement and modification made without departing from the scope of the present invention all should be of the invention Within protection scope.

Claims (10)

1. a kind of wash process coproduction high concentration liquid CO using low-temp methanol2Method, which is characterized in that including high concentration liquid CO2Production process and low-temp methanol wash process,
The high concentration liquid CO2Production process the following steps are included:
(A) richness CO2It is cooling after unstripped gas dehydration, it is re-fed into the first knockout drum；
(B) liquid phase stream of the first gas-liquid separation pot bottom condensation is sent into CO2Product purifying column purification, CO2Product purifying column Bottom is refining to obtain high-purity liquid CO2, gas phase of the top gaseous phase after compressing pressure-raising with the output of the first gas-liquid separation tank top Logistics is sent into decarburization tower bottom together as carbonaceous gas；
The low-temp methanol wash process the following steps are included:
(C) the low temperature poor methanol at the top of decarbonizing tower absorbs the carbon dioxide from the carbonaceous gas that decarburization tower bottom enters, as Rich methanol is exported from decarburization tower bottom, wherein and a part enters methane stripper-overhead, and another part enters at the top of desulfurizing tower, It is discharged after the heat exchange of decarbonizing tower top gaseous phase；
(D) enter the rich methanol at the top of desulfurizing tower as absorbent, handle the pretreated sulfur-bearing entered from desulfurization tower bottom Gaseous mixture, wherein desulfurizing tower tower bottom liquid phase rich methanol enters H2S concentration tower is discharged after the heat exchange of desulfurizing tower top gaseous phase a part, Another part enters methane stripping tower tower bottom；
(E) the part rich methanol of decarburization tower bottom enters methane gas stripper overhead after depressurizing, then through methane stripping tower bottom Part top gaseous phase air lift from desulfurizing tower generates methane rich gas phase in methane gas stripper overhead and is sent into methanation device, first Enter H after alkane stripping tower tower bottom liquid phase processor2S concentration tower；
(F) enter H from the tower bottom liquid phase that desulfurizing tower and methane stripping tower are discharged2Vacuum flashing in S concentration tower, and with nitrogen air lift, The tail gas emptying that tower top generates, tower bottom are rich in H2The liquid phase of S enters methanol hot recycling tower, after hot recycling, methanol hot recycling tower Tower top is precipitated sour gas and sends out battery limit (BL), and the absorbent poor methanol after tower bottom regeneration, which is sent to decarbonizing tower, to be recycled.
2. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, high concentration liquid CO2In production process:
The rich CO2The dewatered cooling of unstripped gas is divided into precooling and two step of deep condensation, in precooling, rich CO2Unstripped gas A part and CO2Product purifies the high-purity liquid CO of tower bottom output2Heat exchange pre-cooling, another part with from decarbonizing tower and H2S is dense The top gaseous phase of contracting tower discharge, which exchanges heat, to be pre-chilled, then two parts richness CO2Unstripped gas carries out deep condensation together.
3. a kind of utilization low-temp methanol according to claim 2 washes process coproduction high concentration liquid CO2Method, feature It is, CO2The high-purity liquid CO of product purifying column tower bottom output2It is divided into three parts, wherein a part and richness CO2Unstripped gas changes CO is returned after heat2Product purifying column tower reactor, a part and richness CO2It is vented after unstripped gas heat exchange, remaining a part is used as high concentration liquid Body CO2Output of products.
4. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, in step (D): the pretreatment of sulfur-bearing gaseous mixture are as follows: third knockout drum top gas phase and the 4th gas-liquid separation tank deck Portion's gas phase mix after mixing compression with sulfur-bearing conversion gas, liquid methanol, then with the part tower top of the discharge at the top of the desulfurizing tower After gas phase heat exchange, into the second knockout drum, the top sulfur-bearing gaseous mixture isolated enters desulfurizing tower processing, and bottom liquid phases are sent Enter subsequent methanol-water separating；
Desulfurizing tower tower bottom liquid phase enters H2It is also pre-processed before S concentration tower, specifically:
Desulfurizing tower tower bottom liquid phase is cooling by heat exchange, depressurizes, and into third knockout drum, isolates top gas phase after compression Desulfurizing tower processing is returned to, bottom liquid phases enter H2S concentration tower.
5. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, in step (E) methane stripping tower:
Top gaseous phase, which first exchanges heat, precools the top gaseous phase that is discharged from methanol hot recycling tower, then send to methanation device；
Tower bottom liquid phase first exchanges heat cooling, decompression, is re-fed into the 4th knockout drum, isolates top gas phase and returns after compression and takes off The processing of sulphur tower, bottom liquid phases enter H2S concentration tower.
6. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, step (F) H2In S concentration tower:
Side output par, c H2S concentration material, respectively and after the tower bottom liquid phase heat exchange that decarbonizing tower and methanol hot recycling tower are discharged, Return again to H2It is handled in S concentration tower；
Tower bottom H2S enters methanol hot recycling tower after liquid phase material and the heat exchange of methanol hot recycling tower tower bottom liquid phase is concentrated.
7. a kind of utilization low-temp methanol according to claim 6 washes process coproduction high concentration liquid CO2Method, feature It is, in step (F) methanol hot recycling tower:
Top gaseous phase enters the 5th knockout drum after condensing, and isolates top gas phase and sends out battery limit (BL), bottom liquid phases return to first Alcohol hot recycling tower.
8. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, rich CO2Water content after unstripped gas dehydration is less than 100ppm.
9. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, rich CO2Stream temperature when entering the first knockout drum after unstripped gas condensation is 0 DEG C~-56 DEG C, preferably -5 DEG C ~-40 DEG C.
10. a kind of utilization low-temp methanol according to claim 1 washes process coproduction high concentration liquid CO2Method, feature It is, CO2The tower top pressure of product purifying column is 0.5MPa (G)~6MPa (G), and temperature is -15 DEG C~-56 DEG C, tower bottom pressure For 0.5MPa (G)~6MPa (G), temperature is 25 DEG C~-50 DEG C.
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