CN101456556B - Carbon dioxide industrial-scale separation and purification system and method in mixture gas by hydrate method - Google Patents

Carbon dioxide industrial-scale separation and purification system and method in mixture gas by hydrate method Download PDF

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CN101456556B
CN101456556B CN2008102206732A CN200810220673A CN101456556B CN 101456556 B CN101456556 B CN 101456556B CN 2008102206732 A CN2008102206732 A CN 2008102206732A CN 200810220673 A CN200810220673 A CN 200810220673A CN 101456556 B CN101456556 B CN 101456556B
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hydrate
gas
decomposition
tower
temperature
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CN2008102206732A
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CN101456556A (en
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陈朝阳
李小森
颜克凤
杨海健
李刚
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中国科学院广州能源研究所
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    • Y02C10/06
    • Y02P20/124
    • Y02P20/152

Abstract

The invention discloses an apparatus and a method for industrially separating and purifying CO2 in mixed gas by a hydrate method. The system consists of a feed gas pretreatment system, a hydrate separation tower, a micro-bubble jet-loop reaction system, a column bottom hydrate decomposition system, a CO2 product collection system, a hydrate formation and decomposition heat comprehensive utilization system and a tail gas energy recovery system. The method integrates hydrate bubbling reaction technology, spraying reaction technology and micro-bubble jet reaction technology, adopts CO2 reflux displacement fractionation technology to improve the concentration of the CO2 in a hydrate phase, has simple separation technology and device and high separation rate and efficiency, comprehensively utilizes the formation heat and decomposition heat of the hydrate during refrigeration cycle, simultaneously recovers compression work of tail gas and cold energy for feed gas pretreatment, and has low energy consumption and cost during separation. The system and the method can be applied to industrial and continuous separation and purification of the CO2 in the mixed gas such as flue gas (CO2/N2), IGCC synthetic gas (CO2/H2), biomass synthetic gas (CO2/H2), natural gas (CO2/CH4), coal bed gas and the like.

Description

CO in a kind of hydrate mist 2Industrial separation purifying plant and method

Technical field

The present invention relates to CO in a kind of mist 2The industrial separation purification technique, especially a kind of CO that utilizes 2The hydrate process is separated CO in the purification mist 2The industrial separation device and method.

Background technology

Global warming and greenhouse gases CO 2Reduction of discharging is the focus and the difficult point problem of whole world concern at present, and Chinese Government's reduction of greenhouse gas discharge target in 2010 is 1,000,000,000 tons, and it is imperative to reduce discharging, and shoulders heavy responsibilities.CO in the atmosphere 2Concentration raises fast and is mainly derived from extensive energy production discharging gas in the industry, the CO of generating discharging 2Account for global CO 2More than 37.5% of total emission volumn is CO 2The emphasis place that reduces discharging.It is the country of main energy sources with coal that China is one, and this energy resource structure will can not change in considerable time from now on.The coal in China major part is used for generating, reduces discharging CO in the power plant 2Extremely urgent.The direct combusting firepower generating of at present traditional coal will be in leading position, the CO of coal-fired power plant in China's power field in considerable time 2Discharge capacity is the industrial CO of control greatly and concentrated relatively 2The main field of discharging.At present emerging integrated gasification combined cycle plants (IGCC) generation technology is as a kind of " clean coal ", its synthesis gas (CO 2/ H 2) middle CO 2Separation with to seal up for safekeeping be the important component part of IGCC technical research, also be the whether key of real " cleaning " of this technology.

CO 2The reduction of discharging measure can reduce following three classes: (1) improves efficiency of energy utilization and energy-conservation; (2) use non-carbon new and renewable sources of energy; (3) continue to use existing fossil fuel, and take measures to capture the CO that seals discharge up for safekeeping 2Because the restriction of development in science and technology level, first and second kind measure respectively can only be as CO 2Reduce discharging the target of mid-term, long-term endeavour, have only the third measure: CO 2Capture and seal technology (CCS) up for safekeeping and just can in short-term, realize global CO 2The extensive reduction of discharging.The CCS technology comprises CO 2Separation and collection, transport and seal up for safekeeping three aspects, wherein CO 2The separation and collection energy consumption is the highest, and economy is the poorest, accounts for whole C O 2Reducing discharging 60~70% of cost, is CO 2The difficult point and the key restraining factors that reduce discharging.Current, the CCS technical research mainly concentrates on high efficiency, CO cheaply 2Process for separation and purification and technical study; Developed multiple CO 2Separation method and capture technology (capture of burning back, the preceding decarburization of burning, oxygen-enriched combusting etc.), various CO 2The separation and collection method does not have problems technically, but ubiquity CO 2Separating energy consumption height, defect of high cost.Up to now, at CO 2The separation and collection aspect does not also have any method to become absolute winner to be generally acknowledged by the whole world and accept that various separation methods all have its pluses and minuses and suitable application area.

Separate and contain CO 2The industrial method of admixture of gas mainly contains chemical absorbing, physical absorption, cryogenic separation, transformation absorption to be separated with film etc.The chemical absorbing range of application is narrow, and it is big that absorbent reclaims energy consumption.Chinese patent CN1747774A discloses a kind of CO that separates recovery the secondary angry body that chemical absorption method produces from steel plant etc. that adopts 2Method, this method is utilized steel plant's low-grade heat extraction heating recovery chemical absorbent, separation costs reduces greatly.The deep cooling process for separating investment is higher, and energy consumption is big, only when unit scale is big, just has preferable economy.The subject matter that pressure swing adsorption method exists is the energy consumption height, equipment investment is big, the adsorbent utilization rate is low and loss is big.Present widely used membrane separation process then has chemistry and shortcomings such as poor heat stability, selectivity and flux are not high, disposal ability is limited, product purity is low, poor durability.Develop that novel, efficient gas separates, method of purification has important economic implications.

Hydrate separates CO in the recovery mist 2Be based on and contain CO 2Admixture of gas in the hydrate formation condition difference of each component, each component is separated the back with hydrate and is decomposed in the distribution coefficient difference of hydrate in mutually in the mist with mist, can reach and separate purification CO 2Purpose.The obvious advantage of this technology is that it does not need to resemble and uses the regenerating unit of expensive highly energy-consuming to reclaim solvent the solvent method for absorbing and separating.Compare the CO of hydrate isolation technics in power-plant flue gas with traditional separation method 2And CO in " green coal " integrated gasification combined cycle for power generation 2Separate, put forward dense aspect and have more potentiality.The first, the hydrate isolation technics can carried out more than 0 ℃, can save a large amount of refrigeration energy needed; The second, the gas pressure height that hydrate obtains after separating, pressure reduction is little before and after separating, and can save the required energy of gas boosting; The 3rd, the water reusable edible after the decomposition of hydrate does not have significant loss on the whole procedural theory, and technological process is also simple relatively.The hydrate isolation technics has broad application prospects as novel separation means, and might become the mainstream technology that mist separates.

Though in that some researchs are arranged aspect the hydrate isolation technics, also imperfect abroad, domestic research in this respect then is in the starting stage.CO in the flue gas 2Hydrate separates initial experimental study California Institute of Technology during 1993-1995 to carry out, and states CO in their patent 2Hydrate can generate in a running system, this system was confirmed by Los Alamos National Laboratory afterwards, and then confirmed to realize that the industrialization of hydrate isolation technics has very big potentiality (Wong, S.andBioletti, R.Carbon dioxide separation technologies. (2002) .Carbon﹠amp; EnergyManagement, Alberta Research Council, Edmonton, Alberta, T6N 1E4, Canada.).U.S. Pat 6602326B2 discloses a kind of employing oxolane and forms CO in the promoter separating mixed gas as hydrate 2With N 2Method and technology, hydrate forms pressure and reduces products C O after three grades of separation greatly 2Concentration can reach 99.8%, but the direct emptying of tail gas after every grade of hydration reaction of this technology causes CO in the flue gas 2The rate of recovery low, be to improve CO 2The rate of recovery must prolong the hydration reaction time, makes hydration reaction reach poised state, causes system's separating power to reduce.U.S. Pat 20050120878A1 discloses a kind of CO that utilizes in the Hydrate Technology separation of methane gas 2Technology.US6352576B1 discloses a kind of employing salt as CO 2Hydrate forms promoter and separates CO in the multicomponent gas 2Method, adopt simultaneously to contain CO 2The water of hydrate nucleus improves hydrate and forms speed, reduces hydrate and forms induction time.The domestic Chen Guang of China University Of Petroleum Beijing advance etc. to have applied for the multinomial patent of utilizing methane and hydrogen in the Hydrate Technology separating ethene cracking gas (CN1762930, CN1762929, CN1762928).

Separate existing certain research though utilize Hydrate Technology to carry out gas, some mechanism, basic problem in science and some key technologies have been solved, and certain patent report is arranged, but do not see the industrial applications report that relevant hydrate mist separates up to now as yet.Main cause is that the continuous isolation technics of hydrate mist will realize that industrial applications must solve the problem of following five aspects: one, adopt suitable hydrate to form promoter and improve hydrate formation speed, reduce hydrate and form the temperature and pressure condition; Two, adopt suitable gas-liquid mixed mode, improve the gas liquid contacting efficiency of hydration reaction, improve hydrate and form speed; Three, the strengthened aqua compound of adopting an effective measure generates the removal of heat; Four, adopt suitable separating technology, realize that hydrate formation gas, liquid, solid three-phase separates automatically under the condition of high voltage; Five, adopt the technology of economical rationality, improve the rate of recovery of separation process object gas and the purity of gas products, reduce the energy consumption of separation process.

Domestic scientific research institutions also disclose a kind of hydrate mist continuous separation method and device (CN1973959A), adopt hydrate to form promoter and reduce hydrate formation temperature and pressure condition, adopt microbubble jet perfectly mixed reactor to improve gas liquid contacting efficiency, adopt the external heat exchanger strengthened aqua compound to generate the removal speed of heat, adopt three stage countercurrents series connection hydrate piece-rate system, separate the CO in the power-plant flue gas continuously 2, CO 2The rate of recovery can reach more than 98% products C O 2Concentration can reach more than 99%, the rate of departure improves greatly.But also there is certain shortcoming in said method, mainly shows to adopt three grades of separation, and separation equipment quantity is many, investment is big, the flow process complexity of gas, liquid, solid three-phase system in system under the condition of high voltage is difficult to control, is unfavorable for energy-conservation and total energy approach etc. in the industrial applications process.

Summary of the invention

The object of the present invention is to provide simple, economic, the CO in the hydrate separating mixed gas efficiently of a kind of separating technology 2Industrial separation purifying plant and method, simplify hydrate separation equipment and operating process, reduce cost of investment and separating energy consumption, improve the stability and the reliability of hydrate lock out operation, be applied to flue gas (CO 2/ N 2), IGCC synthesis gas (CO 2/ H 2), biomass synthesis gas (CO 2/ H 2), natural gas (CO 2/ CH 4), CO in the mist such as coal bed gas 2Industrialization separate continuously.

For realizing above purpose, the present invention has taked following technical scheme: CO in a kind of hydrate mist 2The industrial separation purifying plant includes

A, be used for compressing unstripped gas to predetermined pressure and being cooled to the feed gas preprocessing system of predetermined temperature, it comprises compound compressor, multistage inter-stage heat exchanger and inter-stage gas-liquid separator, be used for compressing unstripped gas to predetermined pressure and being cooled to predetermined temperature, adopt prior art to implement;

B, hydrate knockout tower, it is divided into CO from tower still to cat head 2Displacement fractionation zone, blistering reaction district, spray reaction zone are used to receive the unstripped gas that the feed gas preprocessing system carries, and make unstripped gas fully separate in the hydrate knockout tower; CO 2Displacement fractionation zone and blistering reaction district are hollow cylinder, and inner filling water compound slurries are continuous phase, and the unstripped gas charging aperture is CO 2The separation in displacement fractionation zone and blistering reaction district; The gas that hydration reaction does not take place accumulates in the spray reaction zone, is continuous phase, and gas-liquid interface is the separation of blistering reaction district and spray reaction zone; The operating pressure in tower Zhong Ge district identical (ignoring the fluid column static pressure), but temperature constantly reduces from tower still to cat head.

C, microbubble jet circulating reaction system are used to aspirate the mist that hydrate reaction does not take place in the described hydrate knockout tower, promote the quick generation of the hydrate in the spray reaction zone; Comprise the microbubble jet reactor that is communicated with the top of described spray reaction zone, this microbubble jet reactor also is connected with external primary cooler and circulating pump in turn, also be connected with auxiliary cooler between described microbubble jet reactor and external primary cooler, the effect of auxiliary cooler is can not reach cooling at external primary cooler to provide cold energy by the external refrigeration system when requiring; Extract hydrate slurry by circulating pump from the hydrate knockout tower, be cooled to through external primary cooler and auxiliary cooler that subcooled water compound slurries are laggard goes into the microbubble jet reactor, swabbing action by the microbubble jet reactor sucks the microbubble jet reactor with the mist circulation that hydrate reaction does not take place cat head simultaneously, gas-liquid two-phase returns hydrate and separates cat head after the microbubble jet reactor fully mixes, the effect of generation spray, promote the quick generation of spray reaction zone hydrate, reach by said process and improve hydrate reaction speed, reduce tail gas concentration and remove the purpose that hydrate generates heat.

D, tower still decomposition of hydrate system comprise decomposition of hydrate device and auxiliary decomposer, and the effect of auxiliary decomposer is the heat that decomposition of hydrate is provided by the external heat system when the decomposition of hydrate device can not satisfy the decomposition of hydrate load; The hydrate slurry that is deposited at the bottom of the tower enters decomposition of hydrate device and auxiliary decomposer, and heating is decomposed into water and CO 2, water and portion C O 2Because density diminishes, at the bottom of the tower of backflow backwater compound knockout tower, another part CO 2Rise to CO 2The product acquisition system is collected, by control CO 2The collecting amount of product is controlled CO 2Capacity of returns.

E, CO 2The product acquisition system, it is connected with described tower still decomposition of hydrate system, is used for the isolated CO of acquisition system 2Comprise product collection tube, air accumulation jar and gather control valve, this product collection tube one end is communicated with described decomposition of hydrate device and outputs to described CO by porous backflow distributor 2In the displacement fractionation zone, its other end is by air accumulation jar and gas collecting control valve output gaseous state CO 2, the product collection tube is vertically installed, and extends to the above certain altitude of liquid level of hydrate slurry in the hydrate knockout tower, and air accumulation jar and collection control valve are installed in more than the liquid level of hydrate slurry in the hydrate knockout tower equally.

F, hydrate generate and divide analgesic utilization system.By by the kind of refrigeration cycle of liquefied ammonia, for decomposition of hydrate provides branch analgesic and remove hydrate and form heat as medium.Comprise by with described CO 2Decomposition of hydrate device, auxiliary condenser, ammonia compressor, external primary cooler, auxiliary evaporator, throttle expansion valve that displacement fractionation zone bottom connects constitute refrigeration cycle; In the hydrate separation process, hydrate generates the removal of heat and the supply of decomposition of hydrate heat, and the energy of consumption is big, because in the separation process, the generation of hydrate is hot and divide analgesic quantity suitable substantially, but taste is different, directly integrated utilization; The present invention is according to These characteristics, between decomposition of hydrate device and external primary cooler, set up ammonia compressor and throttle expansion valve, adopt liquefied ammonia as refrigerant, set up cooling cycle system, the decomposition of hydrate device is as the condenser of cooling cycle system, and external primary cooler is as the evaporimeter of refrigeration system; The compressed machine compression temperature of ammonia steam raises, gasification, and entering the decomposition of hydrate device provides decomposition of hydrate required heat energy, the ammonia steam condensateization, and temperature reduces; Enter through the throttle expansion valve expansion through cooled liquefied ammonia, pressure, temperature all reduce; Low-temperature liquid ammonia enters external primary cooler absorption hydrate and forms heat, the liquefied ammonia vaporization, and temperature raises, and ammonia vaporised steam enters compressor compresses then, finishes kind of refrigeration cycle; For the condensation ability that prevents cooling cycle system decomposition of hydrate device and the evaporability of external primary cooler do not match, in the circulatory system, set up auxiliary condenser and auxiliary evaporator compensates.

G, be used to reclaim CO 2The tail gas energy recovery system of separating the back residual exhaust is because CO 2Separate the remaining tail gas in back and have higher pressure and lower temperature, particularly CO in unstripped gas 2When content hanged down, tail gas was large-minded, and wherein pressure potential that is comprised and cold energy quantity are big; The present invention adopts multistage expansion turbine and multistage inter-stage heat exchanger to reclaim the work done during compression and the cold energy of tail gas, and the low temperature exhaust gas after expanding is used for the cooling of feed gas preprocessing process, and the tail gas energy removal process adopts prior art to implement.

At the inner column plate of installing of described spray reaction zone; Raw material gas inlet and tower still CO at described hydrate knockout tower 2Porous feed distributor and porous backflow distributor are all installed by gas or liquid refluxing opening place.The column plate that is arranged in the spray reaction zone helps lend some impetus to gas liquid contacting efficiency, and the gas that hydration reaction does not take place accumulates in the spray reaction zone, is continuous phase; Porous feed distributor and porous backflow distributor can improve blistering reaction district and CO 2Displacement fractionation zone solution-air or liquid-liquid contacting efficiency and hydration reaction speed.

The present invention also provides CO in a kind of hydrate mist 2The industrial separation method of purification comprises the steps:

1) at first inject a certain amount of promoter aqueous solution that contains by circulating pump in whole hydrate piece-rate system, the auxiliary cooler by the microbubble jet reaction circulatory system reduces aqueous temperature to hydrate and generates temperature;

2) unstripped gas to be separated separates preliminary treatment through multi-stage compression, multistage cooling, multi-stage gas-liquid, makes its pressure be elevated to the operating pressure of hydrate knockout tower, and temperature is reduced to hydrate and generates temperature;

3) enter the blistering reaction district of hydrate knockout tower through pretreated unstripped gas through the porous feed distributor, rise, contact formation CO with the low temperature hydrate slurry in the form of blistering reaction district unstripped gas with bubbling 2The mixed gas hydrate that content is high is because CO 2Hydrate density is greater than solution density, and hydrate crystal grain enters CO to deposit 2The displacement fractionation zone, the gas that hydration reaction does not take place rises to the spray reaction zone; Gas rises in the process of cat head and sprays the reverse formation hydrate that contacts of the subcooled water compound slurries that get off from cat head microbubble jet reactor along the spray reaction zone, and hydrate solids is with flowing to the blistering reaction district under the aqueous solution, the CO in the gas phase 2Concentration constantly reduce;

4) be settled down to CO 2The hydrate solids of displacement fractionation zone further to the enrichment of tower bottom sediments, enters tower still decomposition of hydrate system because density is big, is warming up to the decomposition of hydrate temperature, is decomposed into water and liquid state or gaseous state CO 2, water and portion C O 2At the bottom of the porous liquid distributor is back to tower, the CO of backflow 2Because density is less than the density of water, with bubble or drop form along CO 2The displacement fractionation zone rises; Because CO 2Displacement fractionation zone temperature constantly raises from top to bottom, hydrate solids temperature in tower bottom sediments process raises, simultaneously with the CO of the high concentration that at the bottom of tower, refluxes 2Counter current contacting, partially mixed gas hydrate decomposes, and forms CO simultaneously 2Hydrate, the CO in the gas phase 2Displace the N of hydrate in mutually 2Deng the difficult gas that forms hydrate; Hydrate solids is to the tower bottom sediments, and displacement reaction is carried out continuously, the middle mutually CO of hydrate 2Concentration constantly raise and CO in backflow gas phase or the liquid phase 2Concentration constantly reduces;

5) in the separation process, extract the part hydrate slurry out from the circulation of hydrate knockout tower middle part, be cooled to through external primary cooler and auxiliary cooler that subcooled water compound slurries are laggard goes into the microbubble jet reactor, swabbing action by the microbubble jet reactor sucks the microbubble jet reactor with the mist circulation that hydration reaction does not take place cat head simultaneously, gas-liquid two-phase returns hydrate and separates cat head after the microbubble jet reactor fully mixes, the effect of generation spray, the CO in the cat head mist 2Concentration further reduces, tower top temperature reduces, and reaches separation requirement and removes the purpose that hydrate generates heat;

6) the poor CO of cat head 2Gas stablize extraction as tail gas by the tail gas control valve, work done during compression and cold energy by in the tail gas of tail gas energy recovery system recovery low temperature, high pressure are used for the compression and the cooling of feed gas preprocessing system;

7) another part CO of going out of tower still decomposition of hydrate system decomposition 2Rise to CO along product collection tube bubbling 2The product acquisition system is collected, by control CO 2The collecting amount of product is controlled CO 2Capacity of returns.

The operating pressure in hydrate knockout tower Zhong Ge of the present invention district is identical, and temperature raises from top to bottom continuously, gas phase and the middle mutually CO of hydrate 2Concentration raises from top to bottom continuously; Hydrate separates tower top temperature greater than 273.15K, the operating pressure of hydrate knockout tower is by cat head operating temperature and the decision of tail gas concentration, temperature after the feed gas preprocessing is formed decision by operating pressure and unstripped gas, and tower still decomposition of hydrate system temperature is formed decision by operating pressure and product; The hydrate phase balance temperature deducted certain degree of supercooling (generation motive force) under operating pressure that described hydrate generation temperature is a knockout tower and mist were formed, and the hydrate phase balance temperature added certain decomposition motive force under operating pressure that described decomposition of hydrate temperature is a knockout tower and mist were formed.

The described promoter aqueous solution that contains, the content of its hydrate formation promoter is 0.1%~50%, described hydrate formation promoter is selected from one of following or its mixture: oxolane, 1,4-dioxane, acetone, quaternary ammonium salt, sulfonium salt, phosphonium salt, fluorochlorohydrocarbon, high-carbon hydrocarbon, lauryl sulfate or dodecane sulfonate.

When the operating pressure of described hydrate knockout tower less than the decomposition of hydrate device in temperature and CO 2During liquefaction pressure under forming, the decomposition of hydrate product is gaseous state CO 2, CO 2Gas rises along product collection tube bubbling, is focused to the air accumulation jar, gathers gaseous state CO by the gas collecting control valve 2Product; When the operating pressure of hydrate knockout tower greater than the decomposition of hydrate device in temperature and CO 2During liquefaction pressure under forming, the decomposition of hydrate product is liquid CO 2, liquid CO 2Because of density rises along the product collection tube less than water, and carry out fractionation with the aqueous solution in the product collection tube, accumulate in the top of product collection tube, liquid level is higher than hydrate slurry liquid level in the hydrate knockout tower, can directly gather liquid CO by the liquid acquisition control valve 2Product.

The present invention compared with prior art has following advantage: the present invention is integrated hydrate blistering reaction technology, spray reaction technology and microbubble jet reaction technology, and adopt CO 2The displacement fractionating technology that refluxes improves the middle mutually CO of hydrate 2Concentration, separation method and system are simple, the rate of departure and efficient improve greatly; It is analgesic with branch to utilize hydrate to generate heat by the kind of refrigeration cycle process synthesis, reclaims tail gas work done during compression and cold energy simultaneously and is used for feed gas preprocessing, has significantly reduced the energy consumption and the cost of separation process; The present invention can be applicable to flue gas (CO 2/ N 2), IGCC synthesis gas (CO 2/ H 2), biomass synthesis gas (CO 2/ H 2), natural gas (CO 2/ CH 4), CO in the mist such as coal bed gas 2Industrialization separate purification continuously.

Description of drawings

Fig. 1 is CO in the hydrate mist of the present invention 2Industrial separation purifying technique flow process and apparatus structure schematic diagram;

Description of reference numerals: 1, feed gas compressor, 2, interstage heat exchanger, 3, turbo-expander, 4, the inter-stage gas-liquid separator, 5, the hydrate knockout tower, 501, CO 2The displacement fractionation zone, 502, the blistering reaction district, 503, the spray reaction zone, 5031, column plate, 504, raw material gas inlet, 6, the porous feed distributor, 7, the tail gas control valve, 8, gas-liquid separator, 9, the microbubble jet reactor, 10, the gas collecting control valve, 11, the air accumulation jar, 12, the liquid acquisition control valve, 13, auxiliary cooler, 14, the product collection tube, 15, circulating pump, 16, external primary cooler, 17, auxiliary evaporator, 18, throttle expansion valve, 19, ammonia compressor, 20, auxiliary condenser, 21, the decomposition of hydrate device, 22, auxiliary decomposer, 23, porous backflow distributor.

The specific embodiment

Below in conjunction with the drawings and specific embodiments content of the present invention is described in further details.

Embodiment:

See also shown in Figure 1ly, flow is 100kmol/h, and pressure is 1bar, and temperature is the unstripped gas (power-plant flue gas) of 373.15K, its CO 2Molar concentration be 17%, flue gas enters hydrate knockout tower 5 from raw material gas inlet 504 by porous feed distributor 6 after 1 compression of three grades of feed gas compressors, 2 coolings of level Four interstage heat exchanger, three grades of inter-stage gas-liquid separator 4 preliminary treatment, flue gas pressures reaches 24.46bar, temperature 280.25K; Adopt circulating pump 15 to the hydrate knockout tower inject TBAB (TBAB) content be 7.5% contain the promoter aqueous solution, make CO 2Displacement fractionation zone 501 and blistering reaction district 502 are full of and contain the promoter aqueous solution; Enter hydrate knockout tower 5 through pretreated flue gas and carry out the hydration separation reaction, the operating pressure of hydrate knockout tower is 24.46bar, tower top temperature is 273.65K, gas approach temperature 280.25K, tower still decomposition of hydrate device 21 temperature are 286.45K, and temperature reduces on following continuously in the hydrate knockout tower.

Flue gas enters the blistering reaction district 502 of hydrate knockout tower with the form of bubbling after porous feed distributor 6 disperses, in the blistering reaction district, flue gas contains the promoter aqueous solution with low temperature and contacts, and forms CO 2The mixed gas hydrate crystal grain that content is high, hydrate crystal grain with contain the promoter aqueous solution and form hydrate slurry; The gas that hydration reaction does not take place rises to spray reaction zone 503 along the blistering reaction district, contact the generation mixed gas hydrate closely with the subcooled water compound slurries that spray from cat head microbubble jet reactor 9, hydrate solids is with flowing to blistering reaction district 502 under the aqueous solution, the CO in the gas phase 2Concentration constantly reduces; Generate heat and reduce CO in the cat head tail gas for removing hydrate 2Content, in the separation process, adopt circulating pump 15 to extract the part hydrate slurry out from the circulation of hydrate knockout tower middle part, be cooled to through external primary cooler 16 and auxiliary cooler 13 that subcooled water compound slurries are laggard goes into the microbubble jet reactor, swabbing action by the microbubble jet reactor sucks the microbubble jet reactor with the mist circulation that hydration reaction does not take place cat head simultaneously, gas-liquid two-phase returns hydrate and separates cat head after the microbubble jet reactor fully mixes, the effect of generation spray, the CO in the cat head mist 2Concentration further reduces, tower top temperature reduces; Accumulate in the poor CO of cat head 2Gas is stablized extraction, CO in the tail gas as tail gas by gas-liquid separator 8 and tail gas control valve 7 2Content is 3.95%, exhaust flow 86.12kmol/h, tail gas pressure 24.46bar, temperature 273.65K; Owing to have higher pressure and lower temperature in the tail gas, adopt two stage turbine decompressor 3 and two-stage inter-stage heat exchanger 2 to reclaim the work done during compression and the cold energy of tail gas, be used for the compression and the cooling of feed gas preprocessing system.

The hydrate slurry that blistering reaction district 502 and spray reaction zone 503 generate enters CO because density is bigger to deposit 2Displacement fractionation zone 501 is settled down to CO 2The hydrate solids of displacement fractionation zone 501 is further to the enrichment of tower bottom sediments, enters tower still decomposition of hydrate device 21 and auxiliary decomposer 22 and heats up and be decomposed into water and gaseous state CO 2, water and portion C O 2At the bottom of porous backflow distributor 23 was back to tower, reflux ratio was 0.5, the CO of backflow 2Because density is little, with bubble form along CO 2Displacement fractionation zone 501 rises; Because CO 2Displacement fractionation zone 501 temperature constantly raise from top to bottom, hydrate solids temperature in tower bottom sediments process raises, simultaneously with the CO of the high concentration that at the bottom of tower, refluxes 2The back flow of gas contact, partially mixed gas hydrate decomposes, and forms CO simultaneously 2Hydrate, the CO in the gas phase 2Displace the N of hydrate in mutually 2Deng the difficult gas that forms hydrate, hydrate solids is to the tower bottom sediments, and displacement reaction is carried out continuously, the middle mutually CO of hydrate 2Concentration constantly raise and CO in the gas phase 2Concentration constantly reduces; Another part CO that tower still decomposition of hydrate system decomposition goes out 2Gas rises to air accumulation jar 11 along product collection tube 14 bubblings, stablizes extraction by gas collecting control valve 10 then, by control CO 2The collecting amount of product is controlled CO 2Capacity of returns, the CO of collection 2Gas flow is 13.88kmol/h, products C O 2Content 98%.

For the comprehensive utilization hydrate generates heat and decomposition of hydrate heat, reduce separating energy consumption, utilize decomposition of hydrate device 21 and external primary cooler 16 condenser and evaporimeter respectively as cooling cycle system, set up ammonia compressor 19 and throttle expansion valve 18, adopt liquefied ammonia as refrigerant, set up cooling cycle system, provide required heat of decomposition of hydrate and hydrate to form required cold by the liquefied ammonia kind of refrigeration cycle, for the condensation ability that prevents decomposition of hydrate device 21 in the cooling cycle system and the evaporability of external primary cooler 16 do not match, in the circulatory system, set up auxiliary condenser 20 and auxiliary evaporator 17 compensates.

When the operating pressure of hydrate knockout tower greater than the decomposition of hydrate device in temperature and CO 2During liquefaction pressure under forming, the decomposition of hydrate product is liquid CO 2, because liquid CO 2Density is less than the density of water, liquid CO 2Rise along product collection tube 14, and carry out fractionation with the aqueous solution in the product collection tube, accumulate in the top of product collection tube 14, liquid level is higher than hydrate slurry liquid level in the hydrate knockout tower 5, can directly gather liquid CO by liquid acquisition control valve 12 2Product.

Adopt above-mentioned same technological process, hydrate formation promoter can be used instead and be selected from one of following or its mixture: oxolane, 1,4-dioxane, acetone, quaternary ammonium salt, sulfonium salt, phosphonium salt, fluorochlorohydrocarbon, high-carbon hydrocarbon, lauryl sulfate or dodecyl sodium sulfonate; The content that contains the promoter aqueous solution changes between 0.1%-50%, all can obtain good CO 2Separating effect.

Adopt above-mentioned same technological process, carry out IGCC synthesis gas (CO 2/ H 2), biomass synthesis gas (CO 2/ H 2), natural gas (CO 2/ CH 4) and coal bed gas in CO 2Separate, all can obtain good separating effect.

Above-listed detailed description is at the specifying of possible embodiments of the present invention, and this embodiment is not in order to limiting claim of the present invention, and the equivalence that all the present invention of disengaging do is implemented or change, all should be contained in the claim of this case.

Claims (9)

1. CO in the hydrate mist 2The industrial separation purifying plant includes and is used for compressing unstripped gas to predetermined pressure and being cooled to the feed gas preprocessing system of predetermined temperature, is used to reclaim CO 2Separate the tail gas energy recovery system of back residual exhaust, it is characterized in that, also include:
Hydrate knockout tower (5), microbubble jet circulating reaction system, tower still decomposition of hydrate system, CO 2Product acquisition system, hydrate generate and divide analgesic utilization system;
Hydrate knockout tower (5), it is divided into CO from tower still to cat head 2Displacement fractionation zone (501), blistering reaction district (502), spray reaction zone (503) are used to receive the unstripped gas that the feed gas preprocessing system carries, and make unstripped gas fully separate in the hydrate knockout tower;
Microbubble jet circulating reaction system is used to aspirate the mist that hydrate reaction does not take place in the described hydrate knockout tower (5), promotes the quick generation of the hydrate in the spray reaction zone (503);
Tower still decomposition of hydrate system is used to add the hydrate slurry of thermal decomposition at the bottom of from described hydrate knockout tower (5) tower, water and portion C O 2Be back at the bottom of hydrate knockout tower (5) tower another part CO 2Output to described CO 2The product acquisition system;
CO 2The product acquisition system, it is connected with described tower still decomposition of hydrate system, is used for the isolated CO of acquisition system 2
Hydrate generates and divides analgesic utilization system, by by the kind of refrigeration cycle of liquefied ammonia as medium, forms heat for decomposition of hydrate provides the analgesic and removal hydrate of branchs.
2. CO in the hydrate mist as claimed in claim 1 2The industrial separation purifying plant, it is characterized in that: described microbubble jet circulating reaction system comprises the microbubble jet reactor (9) that is communicated with the top of described spray reaction zone (503), and this microbubble jet reactor (9) also is connected with external primary cooler (16) and circulating pump (15) in turn.
3. CO in the hydrate mist as claimed in claim 2 2The industrial separation purifying plant is characterized in that: also be connected with auxiliary cooler (13) between described microbubble jet reactor (9) and external primary cooler (16).
4. CO in the hydrate mist as claimed in claim 1 2The industrial separation purifying plant is characterized in that: described hydrate generate and divide analgesic utilization system include by with described CO 2Decomposition of hydrate device (21), auxiliary condenser (20), ammonia compressor (19), external primary cooler (16), auxiliary evaporator (17) and throttle expansion valve (18) that displacement fractionation zone (501) bottom connects constitute refrigeration cycle, provide required heat of decomposition of hydrate and hydrate to form required cold by the liquefied ammonia kind of refrigeration cycle.
5. CO in the hydrate mist as claimed in claim 1 2The industrial separation purifying plant is characterized in that: the inner column plate (5031) of installing of described spray reaction zone (503); On described hydrate knockout tower (5), be provided with raw material gas inlet (504), described raw material gas inlet (504) and tower still CO 2Gas or liquid refluxing opening place install porous feed distributor (6) and porous backflow distributor (23) respectively.
6. CO in the hydrate mist as claimed in claim 1 2The industrial separation purification system is characterized in that: described CO 2The product acquisition system includes product collection tube (14), and air accumulation jar (11), gas collecting control valve (10), these product collection tube (14) one ends are communicated with decomposition of hydrate device (21) and output to described CO by porous backflow distributor (23) 2In the displacement fractionation zone (501), its other end is by air accumulation jar (11) and gas collecting control valve (10) output gaseous state CO 2
7. CO in the hydrate mist 2The industrial separation method of purification is characterized in that, comprises the steps:
(1) injection contains the promoter aqueous solution in the hydrate piece-rate system, reduces aqueous temperature to hydrate by the microbubble jet reaction circulatory system and generates temperature;
(2) unstripped gas to be separated separates preliminary treatment through multi-stage compression, multistage cooling with multi-stage gas-liquid, makes its pressure be elevated to the operating pressure of hydrate knockout tower, and temperature is reduced to hydrate and generates temperature;
(3) the pretreated unstripped gas of process enters the blistering reaction district of hydrate knockout tower, rises in the form of blistering reaction district unstripped gas with bubbling, contacts with the low temperature hydrate slurry and forms CO 2The mixed gas hydrate that content is high, hydrate crystal grain enters CO to deposit 2The displacement fractionation zone, the gas that hydration reaction does not take place rises to the spray reaction zone; Gas rises in the process of cat head and sprays the reverse formation hydrate that contacts of the subcooled water compound slurries that get off from cat head microbubble jet reactor along the spray reaction zone, and hydrate solids is with flowing to the blistering reaction district under the aqueous solution;
(4) be settled down to CO 2The hydrate solids of displacement fractionation zone enters tower still decomposition of hydrate system further to the enrichment of tower bottom sediments, is warming up to the decomposition of hydrate temperature, is decomposed into water and liquid state or gaseous state CO 2, water and portion C O 2At the bottom of porous backflow distributor is back to tower, the CO of backflow 2With bubble or drop form along CO 2The displacement fractionation zone rises; Because CO 2Displacement fractionation zone temperature constantly raises from top to bottom, hydrate solids temperature in tower bottom sediments process raises, simultaneously with the CO of the high concentration that at the bottom of tower, refluxes 2Counter current contacting, partially mixed gas hydrate decomposes, and forms CO simultaneously 2Hydrate, the CO in the gas phase 2Displace the N of hydrate in mutually 2Deng the difficult gas that forms hydrate; Hydrate solids is to the tower bottom sediments, and displacement reaction is carried out continuously, the middle mutually CO of hydrate 2Concentration constantly raise and CO in backflow gas phase or the liquid phase 2Concentration constantly reduces;
(5) in the separation process, extract the part hydrate slurry out from the circulation of hydrate knockout tower middle part, subcooled water compound slurries are laggard goes into the microbubble jet reactor through being cooled to, swabbing action by the microbubble jet reactor sucks the microbubble jet reactor with the mist circulation that hydration reaction does not take place cat head simultaneously, gas-liquid two-phase returns hydrate and separates cat head after the microbubble jet reactor fully mixes, the effect of generation spray, the CO in the cat head mist 2Concentration further reduces, tower top temperature reduces, and reaches separation requirement and removes the purpose that hydrate generates heat;
(6) the poor CO of cat head 2Gas stablize extraction as tail gas by the tail gas control valve, work done during compression and cold energy by in the tail gas of tail gas energy recovery system recovery low temperature, high pressure are used for the compression and the cooling of feed gas preprocessing system;
(7) another part CO of going out of tower still decomposition of hydrate system decomposition 2Rise to CO along product collection tube bubbling 2The product acquisition system is collected, by control CO 2The collecting amount of product is controlled CO 2Capacity of returns.
8. CO in the hydrate mist as claimed in claim 7 2The industrial separation method of purification, it is characterized in that: the described promoter aqueous solution that contains, the content of its hydrate formation promoter is 0.1%~50%, described hydrate formation promoter is selected from one of following or its mixture: oxolane, 1,4-dioxane, acetone, quaternary ammonium salt, sulfonium salt, phosphonium salt, fluorochlorohydrocarbon, high-carbon hydrocarbon, lauryl sulfate or dodecane sulfonate.
9. CO in the hydrate mist as claimed in claim 7 2The industrial separation method of purification is characterized in that: when the operating pressure of described hydrate knockout tower less than decomposition of hydrate device (21) in temperature and CO 2During liquefaction pressure under forming, the decomposition of hydrate product is gaseous state CO 2, CO 2Gas rises along product collection tube (14) bubbling, is focused to air accumulation jar (11), gathers gaseous state CO by gas collecting control valve (10) 2Product; When the operating pressure of hydrate knockout tower (5) greater than the decomposition of hydrate device in temperature and CO 2During liquefaction pressure under forming, the decomposition of hydrate product is liquid CO 2, liquid CO 2Because of density rises along product collection tube (14) less than water, and in product collection tube (14), carry out fractionation with the aqueous solution, accumulate in the top of product collection tube (14), liquid level is higher than the interior hydrate slurry liquid level of hydrate knockout tower (5), can directly gather liquid CO by liquid acquisition control valve (12) 2Product.
CN2008102206732A 2008-12-31 2008-12-31 Carbon dioxide industrial-scale separation and purification system and method in mixture gas by hydrate method CN101456556B (en)

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