CN103304358B - Separating method and equipment of low-carbon olefins beneficial to product recovery - Google Patents
Separating method and equipment of low-carbon olefins beneficial to product recovery Download PDFInfo
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Abstract
The invention discloses a separating method and corresponding equipment of low-carbon olefins beneficial to product recovery. The separating method comprises the steps of: pretreating and delivering oxygenated chemical-converted low-carbon olefin flow into a depropanization system, cooling and delivering top products of the depropanization system into a demethanizing tower, cooling the top of the demethanizing tower only with a propylene refrigerant, delivering vapor phase at the tower top into a pressure swing adsorption device for recovering ethylene, returning the recovered crude ethylene gas back before a segment of compressor to be mixed with low-carbon olefin reaction gas flow, so that a copious cooling cold box and an ethylene refrigeration compressor are omitted, and the fixed investment and energy consumption can be reduced. Compared with the prior art, the separating method and corresponding equipment have the advantages of being low in separating energy consumption, high in material recovery rate, small in influence on the following ethylene and propylene separation, and the like.
Description
Technical field
The invention belongs to low-carbon alkene separation, purification techniques field, relate to one with oxygenatedchemicals (mainly methyl alcohol, ethanol, dme, C4 ~ C10 alkylol cpd or its mixture etc.) for raw material, production is in the process of main streams (mainly ethene and propylene) with low-carbon alkene, the separation method of its product low carbon olefin gas and equipment thereof.
Background technology
Traditional ethene and the source of propylene mainly petroleum hydrocarbon steam cracking, its raw material mainly petroleum naphtha, and China's oil resource scarcity, this is the major cause of restriction China Ethylene Development.Along with the growing tension of oil supply, oxygenatedchemicals preparing low-carbon olefins (OTO technique) becomes the focus of research, its representational methanol-to-olefins technology (MTO) is day by day ripe, opens the new technology route by coal or natural gas via gasification production basis Organic Chemicals.
Be that the oxygen-containing organic compound of representative to mainly contain MTO technology (mainly US Patent No. 6166282, the US 5744680 of American UOP company at present for raw material production based on the low-carbon alkene technique of ethene and propylene with methyl alcohol; Chinese patent CN 1359753A), (main patent is US 6673978, US 6717023, US 6613950 for the MTO technology of ExxonMobil company of the U.S.; Chinese patent CN 1352627A, CN 1681753A), the DMTO technology (CN 1166478A, CN 1084431A) of MTP technique (EP 0448000A, DE 233975A) and the Dalian Chemistry and Physics Institute of the Chinese Academy of Sciences.
CN 1962579A discloses a kind of separation method of carbon-containing olefin cracked product, carbon-containing olefin cracked product is first compressed to 1.0 ~ 4.0 MPa by the present invention, enter the first knockout tower, tower top obtains ethene, tower reactor still liquid enters the second knockout tower, tower top obtains C5 and below C5 cut, obtains more than C6 cut at the bottom of tower; C5 and below C5 cut enters the 3rd knockout tower, and the C3 cut that tower top obtains enters the 4th knockout tower, and tower reactor still liquid is C4 and C5 cut; 4th knockout tower lateral line withdrawal function obtains the propylene that weight concentration is 90 ~ 99%, and tower reactor obtains the propane that weight concentration is 80 ~ 95%.
CN 1063051A discloses a kind of energy-saving process for separation of light hydrocarbons, the technical process that the present invention adopts double tower front-end deethanization and low-pressure methane removing to be combined, and takes full advantage of the energy saving of low-pressure methane removing.CN 1157280A discloses a kind of similar flow process, and this invention is double tower front-end deethanization equally, and high pressure deethanizer overhead is through multistage cooling and flash distillation, and liquid is as demethanizing tower charging, and gas sends into methane absorber through cooling; This absorbing tower absorbs ethene using liquid phase methane as absorption agent, and liquid at the bottom of tower is as demethanizing tower charging.
In sum, produce in lower carbon number hydrocarbons at naphtha steam cracking, because hydrogen, methane content are higher, generally adopt deep cooling to come separation of methane and ethene, to improve yield of ethene.Typical deep cooling separating method comprises order separation, front-end deethanization and predepropanization process, and three all needs the Cryogenic Conditions of less than-100 DEG C, needs ethylene compressor, also needs for low-pressure methane removing the cold that methane compressor provides about-135 DEG C.Require also higher to ice chest simultaneously, construction investment is strengthened.
CN 102675019A, CN 102675024A and CN 102675025A disclose a kind of increase carbon monoxide and oxygen removes step guarantee pretreating effect, and by six ice chests and six separating tanks refrigerated separation step by step, finally make the 6th separating tank realize hydrogen and methane separation, obtain molar fraction respectively and be greater than the hydrogen of 90% and the technique of methane.Methane refrigeration compressor is sent into after the fraction of stream that wherein demethanizing tower top produces by CN 102675019A reclaims cold, be cooled to-100 ~-140 DEG C of step-down throttlings again, then cold is reclaimed one by one through ice chest, 5th separating tank bottom liquid successively by entering low-pressure methane compressor after ice chest heat exchange, then enters demethanizing tower after decompression throttling after water cooler and ice chest; Wherein the feature of CN 102675024A is, vapour phase temperature after methane expander of demethanizing return tank is down to 120 ~ 160 DEG C, then successively reclaims cold through ice chest; Wherein the feature of CN 102675025A is, before deethanizing being arranged on separating tank and ice chest.
CN 1847203A discloses the separation method of a kind of converting methanol to prepare low carbon olefin (DMTO) gas, four sections of compressor outlet logistics are sent into deethanizing column by this invention, deethanizing column vapour phase carries out hydrogenation reaction after five sections of compressor pressurizes, then deethanizer reflux tank is entered, return tank liquid phase is as deethanizer reflux, return tank vapour phase enters deep cooling demethanizing system, and material does not need to arrange dehydrogenation system before loaded down with trivial details ice chest after condensing cooling, directly enters high pressure demethanizer.
The feature of its product of preparing low-carbon olefin from oxygen-containing compounds is that hydrogen, methane content are lower, and ethene, propylene content are higher, and the high-carbon hydrocarbon contents such as C5+ are less, the cold causing demethanizing tower to need is less, as adopted deep cooling separating method, high to equipment requirements, investment is large, and energy consumption is high, and economic benefit is not good.
US 7714180 proposes a kind of processing method of olefin recovery.According to the method, first process gas removes C5+ through debutanizing tower after compression, C4-compresses further again, cooling rear first laggard demethanizing tower, deethanizing column, depropanizing tower, and hybrid C 4 at the bottom of depropanizing tower tower is removed the ethene in the top gas of demethanizing tower absorption tower as absorption agent, improves yield of ethene.This invention is avoided adopting deep cooling process for separating, but adopts the technique that oil absorbs, and reduce investment, but for oxygenatedchemicals preparing low carbon hydrocarbons technique, main component is C1 ~ C4 material, a large amount of materials needs the laggard demethanizing tower of precooling, and energy consumption is larger.And hybrid C 4 absorption agent internal circulating load is large and circulation process is long, energy consumption is larger.
US 5326929 and US 5220097 propose a kind of solvent absorbing and are separated hydrogen, methane and carbon two method of component, and the main drawback of the method is the large percentage of solvent and carbon two, and solvent reclamation temperature is very high, may up to 150 DEG C.And then this solvent is cooled to-50 DEG C of laggard methane absorbers.So a large amount of solvents first heats refrigeration cycle again, and energy expenditure is also very remarkable.
CN 101921161A, CN 102115355A, CN 102206128A and CN 102491866A spoken of respectively demethanizing tower introduce absorb flow process, its key distinction be separation sequence and selected cryogen different.Wherein CN 101921161A adopts front decarburization three and fractional condensation cut technology, and absorption agent carbon three is from low pressure depropanizer overhead stream; CN 102115355A employing order separation process, and use ethane, propane or ethane/propane mixture are as absorption agent; CN 102206128A adopts predepropanization process, and absorption agent is the binary mixture of ethane or ethane and propane; CN 102491866A adopts predepropanization process, and absorption agent is the propane at the bottom of from propylene tower tower.
CN 101234946A discloses a kind of separation method of low-carbon (LC) mixed gas, it be add in low-carbon olefin mixed gas carbonatoms be 1 ~ 4 alcohols, in ethers or ketone at least one as absorption agent, effectively absorb the C3 ~ C5 component in low-carbon alkene mixed gas under certain temperature and pressure, then by the method for absorption, desorb, rectifying, the C3 ~ C5 component in low-carbon olefin mixed gas is separated.This inventive method, for the converting methanol to prepare low carbon olefin technique of middle and small scale, has very strong economy.Have process, facility investment is few, the feature that energy consumption is low.
CN 101353286A and CN 101445419A discloses a kind of " precut+oil absorbs " technique, wherein CN 101353286A carries out the non-clear segmentation of C1 and C2 by arranging precut tower, precut column overhead enters absorption tower, with C3, C4, the mixture of C5 or its hydro carbons is as absorption agent separation C1 and C2 wherein, light gas is discharged by top, absorption tower, precut tower is returned at the bottom of tower, and progressively carry out being separated, without independent solvent reclamation equipment of solvent and other components at precut tower and treating tower in succession.But still need propylene refrigerant condenser and a single-stage ethene refrigerant condenser, totally two freezing compression systeies; And CN 101445419A is similar to above-mentioned flow process, just realizes propylene refrigerant replacement ethene cryogen by increasing side cooler on absorption tower, make ethene refrigerant condenser no longer become required.
CN 101367697A discloses the separation method of light hydrocarbon product in a kind of MTO/MTP reaction product, this invention adopts front-end deethanization technique, deethanizer overhead vapour phase is delivered to absorption and is steamed tower, absorption steams tower and adopts the rich absorbent from oil-absorption tower tower reactor to absorb, deethanizing column tower reactor product introduction subsequent separation system; Absorption is steamed column overhead product and send into oil-absorption tower after cooling, oil-absorption tower adopts ethane as poor absorption agent, absorb from the ethene steamed in tower logistics, all the other light gas are discharged from tower top, absorption steams tower tower reactor product introduction ethylene column, as oil scrubber absorption agent after the cooling of ethylene column tower reactor ethane.
CN 102267850A discloses a kind of separation method of low carbon olefin gas, this invention is front-end deethanization flow process, but in order to use C3, one or more in C4 or C5+ cut are as absorption agent, so be provided with desorption tower after demethanizing tower, absorption agent is circulated between demethanizing tower and desorption tower.
CN 101747128A proposes a kind of separation method of converting methanol to prepare low carbon olefin gas, be characterised in that, adopt on the basis of absorption agent at demethanizing tower, at demethanizer overhead, decompressor is set, or built-in cold condenser is set in demethanizing tower simultaneously, make exhaust temperature lower by tower top decompressor thus reduce ethylene loss.
CN 101381270A discloses a kind of separation method of MTO/MTP reaction mixture, the method feature first reaction gas is sent into depropanization system, and C4 depropanization system separated and more than C4 cut Returning reactor continue reaction or directly deliver to debutanizing tower.By C4 and more than C4 hydrocarbon Returning reactor is increased production alkene.
CN 1833017A discloses for from ethane, ethene, propylene, dme, and the new and effective separation method of separation of polymeric level ethene and propylene in one or more initial stream in propane, acetylene, propadiene, methane, hydrogen, carbon monoxide, carbonic acid gas and C4+ component.But this patent does not relate to the data such as service temperature and pressure of tripping device, so be difficult to its superiority-inferiority of detailed assessment.
In addition, three sections of patents of applying for such as CN 103058812, CN 103086827, CN 103073379 individually disclose a kind of olefin separation system and alkene separation method thereof.Three sections of patents are all based on identical theoretical foundation, and namely in temperature and pressure condition one timing, in unstripped gas, CH4/H2 ratio is less, and in tail gas, ethylene loss is larger, and energy consumption is also higher; Conventional cryogenics and Lu Musi technology are owing to being all that an employing demethanizing process is difficult to obtain desirable methane and the ratio of hydrogen, and energy consumption is high, ethylene loss amount large and invest high shortcoming therefore to cause tail gas to exist in the process of separating ethene.Patent arranges just demethanizing tower, secondary demethanizing tower by adopting in olefin separation system, psa unit, film separation unit, psa unit and film separation unit are set respectively between again in conjunction with three kinds of processing modes, first realize being separated of rich hydrogen and rich hydrocarbon, and then realize the separation of alkene again, improve the yield of alkene.
In sum, according to the feature of preparing low-carbon olefin from oxygen-containing compounds product, low temperature separation process is avoided to be rational; For oil wash flow process, the key distinction is that the selection of absorption agent is different with the order of flow arrangement, its main drawback is: solvent cycle amount is very large, after solvent reclamation, refrigeration cycle energy consumption is remarkable, and partially absorb the utility value that agent can remove to reduce as fuel gas with absorbing tower top gas absorption agent itself, flow process selects there is a definite limitation to solvent, sometimes needs to increase desorption apparatus, improves demethanizing tower temperature and makes ethylene loss compared with cryogenic technology become large; Decompressor flow process is set up for " precut+oil absorbs " of improving and demethanizer column overhead, solvent cycle amount can be reduced and reduce exhaust temperature to improve yield, but because solvent is from internal system, process of cooling after the first heating of solvent reclamation, energy consumption cannot be avoided, solvent cycle still can increase later separation energy consumption, particularly in propylene tower charging propylene content reduce, and need cold start-up first set up solvent cycle give drive, stop make troubles.
The quality of low-carbon alkene separation method is typically implemented in energy consumption, investment and product recovery rate three aspects, especially product recovery rate, but these three aspects are conflicting often, the sepn process of low-carbon alkene is broadly divided into demethanizing system, decarburization two system and decarburization three system three parts, the loss overwhelming majority of ethene occurs in demethanizing system, the original intention of the present invention's design is to reduce on the ethylene loss of demethanizing system and the basis of energy consumption as far as possible, strives avoiding causing the impact on succeeding target product separation because of the transformation of demethanizing tower system.
Summary of the invention
Object of the present invention is exactly provide that a kind of less investment, energy consumption are low, material recovery rate is high, affect little non-deep cooling low-carbon alkene separation method to later separation to overcome defect that above-mentioned prior art exists.
The invention provides a kind of low-carbon alkene separation method being beneficial to Product recycling, it is characterized in that: the low-carbon alkene logistics transformed by oxygenatedchemicals is by sending into depropanization system after pre-treatment, demethanizing tower is sent into after the cooling of depropanization system overhead product, demethanizer column overhead only uses propylene refrigerant to cool, overhead vapor phase sends into pressure-swing absorption apparatus recovered ethylene, the crude ethylene gas reclaimed mixes with the logistics of low-carbon alkene reaction gas before being back to one section of compressor.
The present invention is further characterized in that: the described low-carbon alkene separation method being beneficial to Product recycling, specifically comprises the following steps:
(1) logistics of oxygenatedchemicals preparing low-carbon olefin by conversion is after one section of compressor and two sections of compressor compresses, heat exchange, in succession removing oxygenatedchemicals and the pre-treatment such as sour gas and water, form mixture flow with the vapour phase from ethylene polishing column top return tank, after three sections of compressor boost, cooling and dehydrations, enter high pressure depropanizer;
(2) gaseous mixture of high pressure depropanizer tower top generation, compressed and cooling after enter demethanizing tower charging stock tank, in charging stock tank, vehicle repair major enters demethanizing tower top respectively as feed stream, after demethanizer overhead gas cooling out, liquid phase stream returns demethanizing tower, and vapor phase stream enters pressure-swing absorption apparatus;
(3) the pressure-variable adsorption agent in pressure-swing absorption apparatus has good selectivity to ethene, light gas methane in gas mixture can be separated with crude ethylene gas with hydrogen, through sorbent material selective adsorption and the crude ethylene gas of desorb gained is back to one section of compressor mixes with the logistics of low-carbon alkene reaction gas, then enter high pressure depropanizer after a series of process;
(4) high pressure depropanizer tower bottoms is delivered to low pressure depropanizer and is separated further, and low pressure depropanizer overhead product returns high pressure depropanizer, and bottom product reclaims or is separated further;
(5) component at the bottom of demethanizer is delivered to deethanizing column and is carried out being separated of C2 and C3;
(6), after the C2 gaseous mixture that deethanizer overhead produces enters return tank cooling, liquid phase stream returns deethanizing column, and vapor phase stream is sent to hydrogenation or directly sent into ethylene polishing column;
(7) ethylene polishing column carries out being separated of ethene and ethane, ethylene polishing column top lateral line withdrawal function ethene liquid-phase product, and ethylene polishing column bottom product is ethane liquid-phase product;
(8) be C3 liquid mixture at the bottom of deethanizing column tower, send to hydrogenation or directly enter propylene refining tower;
(9) vapour phase of propylene refining tower return tank of top of the tower is propylene vapor-phase product, and propylene refining tower bottom product is propane liquid-phase product.
The present invention is further characterized in that: the pre-treatment of described low-carbon alkene logistics mainly comprises to be carried out primary dewatering, heat exchange, remove oxygenatedchemicals, enters soda-wash tower and remove sour gas after one section of compressor and two sections of compressor pressurizes to 1.8 ~ 3.8 MPa, carries out drying and dehydrating afterwards.
The present invention is further characterized in that: described pretreated low-carbon alkene logistics sends into high pressure depropanizer through three sections of compressor boost, cooling and dehydration, and high pressure depropanizer overhead gas enters four sections of compressors and is compressed to 2.0 ~ 4.0 MPa further.
The present invention is further characterized in that: the alkene mixture of four sections of described compressor outlets enters demethanizing tower charging stock tank after cooler cooling.
The present invention is further characterized in that: described high pressure depropanizer tower bottoms is delivered to low pressure depropanizer and is separated further, low pressure depropanizer overhead product returns high pressure depropanizer, bottom product sends into debutanizing tower system, also can send into oxygenate conversion reactor entrance or fluidized catalytic cracker (FCC) to increase production alkene.
The present invention is further characterized in that: described demethanizing tower charging stock tank top vapour phase out and bottom liquid phase are out respectively as two bursts of chargings of demethanizing tower; In demethanizing tower, not only containing methane, hydrogen, nitrogen and oxygen in overhead vapor phase, also containing part C2 and a small amount of C3, this gas enters demethanizer column overhead return tank after the cooling of demethanizer column overhead condenser, the vapour phase of demethanizer reflux tank top enters pressure-swing absorption apparatus, and the liquid of bottom is then as the backflow of demethanizing tower; At the bottom of demethanizer, liquid phase stream is through reboiler, and reboiler top gas is back to demethanizing tower, and bottom liquid is then delivered to deethanizing column and carried out being separated of C2 with C3.
The present invention is further characterized in that: the described gas entering pressure-swing absorption apparatus is divided into two strands by pressure-variable adsorption, is not wherein mainly hydrogen, methane and nitrogen by adsorbent light component, and this light gas can be used as fuel gas and delivers to out-of-bounds; Or deliver to hydrogen manufacturing pressure-swing absorption apparatus or membrane separation unit and purify further and obtain the highly purified hydrogen that molar content is more than 99.9%; Described by the ethene that adsorbs by desorption rear portion as sweep gas, before rest part is back to one section of compressor, mix with the logistics of low-carbon alkene reaction gas.
The present invention is further characterized in that: described deethanizer overhead vapour phase enters deethanizer overhead return tank after cooling, the liquid-phase reflux of deethanizer reflux tank, to deethanizer overhead, directly sends into ethylene polishing column when acetylene molar content is less than 1ppm in the vapour phase of deethanizer reflux tank after super-dry and cooling; Enter acetylene hydrogenation reactor when its acetylene molar content is more than or equal to 1ppm and carry out hydrogenation reaction, the gaseous mixture containing ethene, ethane produced bottom acetylene hydrogenation reactor, sends into ethylene polishing column after cooling and drying.
The present invention is further characterized in that: the gaseous mixture that described ethylene polishing column tower top produces enters ethylene polishing column return tank after cooling and condensation; The liquid phase of ethylene polishing column return tank returns ethylene polishing column tower top as backflow, and the vapour phase of ethylene polishing column return tank is, before the non-condensable gas of hydrogen and methane returns three sections of compressors, mix with alkali cleaning and the low-carbon alkene logistics after washing; Ethylene polishing column top lateral line withdrawal function ethene liquid-phase product, ethylene polishing column bottom product is ethane liquid-phase product, also tower reactor crude pentafluoroethane can be sent into pressure-swing absorption apparatus recovered ethylene.
The present invention is further characterized in that: be C3 liquid mixture at the bottom of described deethanizing column tower, enters propylene refining tower when its propine molar content is less than 5ppm and propadiene molar content is less than 10ppm after pressurization, heat exchange and drying; After pressurization, heat exchange and drying, enter propine hydrogenator when its propine molar content is more than or equal to 5ppm or propadiene molar content is more than or equal to 10ppm and carry out hydrogenation reaction, next reaction product enters propylene refining tower.
The present invention is further characterized in that: the gaseous mixture that described propylene refining column overhead produces enters propylene refining tower return tank after cooling and condensation, the liquid phase of propylene refining tower return tank returns propylene refining column overhead as backflow, the vapour phase of propylene refining tower return tank is propylene vapor-phase product, and propylene refining tower bottom product is propane liquid-phase product.
The present invention is further characterized in that: described high pressure depropanizer tower top working pressure is 1.8 ~ 3.8MPa, and preferred tower top working pressure is 1.8 ~ 3.3MPa; High pressure depropanizer column bottom temperature is 20 ~ 100 DEG C, and preferred column bottom temperature is 40 ~ 100 DEG C.
The present invention is further characterized in that: described low pressure depropanizer tower top working pressure is 0.5 ~ 1.5MPa, and preferred tower top working pressure is 0.5 ~ 1.2MPa; Low pressure depropanizer column bottom temperature is 20 ~ 100 DEG C, and preferred column bottom temperature is 40 ~ 100 DEG C.
The present invention is further characterized in that: described high and low pressure depropanizing tower tower reactor low-pressure steam or hot water heating.
The present invention is further characterized in that: described demethanizer column overhead working pressure is 2.0 ~ 4.0MPa, and preferred tower top working pressure is 2.2 ~ 3.5MPa; Demethanizer column overhead temperature is more than or equal to-45 DEG C, and preferred tower top temperature is more than or equal to-40 DEG C.
The present invention is further characterized in that: described demethanizing tower column bottom temperature is-15 ~ 45 DEG C, and preferred column bottom temperature is-5 ~ 30 DEG C, and tower reactor adopts circulating water heating.
The present invention is further characterized in that: described pressure-variable adsorption agent is the modified activated carbon of supported copper or silver, the preferably modified activated carbon of supported copper.Adsorptive pressure is 2.2 ~ 3.5MPa, and adsorption temp is-5 ~ 50 DEG C.
The present invention is further characterized in that: described deethanizer overhead working pressure is 1.7 ~ 3.3MPa, and preferred tower top working pressure is 2.0 ~ 3.0MPa; Deethanizing column bottom temperature is 20 ~ 100 DEG C, and preferred bottom temperature is 40 ~ 100 DEG C; Deethanizing column tower reactor uses low-pressure steam or hot water heating.
The present invention is further characterized in that: described ethylene polishing column tower top working pressure is 0.1 ~ 2.2MPa, and preferred tower top working pressure is 1.0 ~ 2.0MPa; Ethylene polishing column column bottom temperature is-40 ~ 30 DEG C, and preferred bottom temperature is-30 ~ 30 DEG C; Ethylene polishing column tower reactor uses circulating water heating.
The present invention is further characterized in that: described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened at 2nd ~ 15 pieces of theoretical stages from tower top to the tower truth of a matter.
The present invention is further characterized in that: described propylene refining column overhead working pressure is 0.1 ~ 2.5MPa, and preferred tower top working pressure is 1.0 ~ 2.2MPa; Propylene refining tower divides cascade towers to operate, C3 mixture enters 2# propylene refining tower, this column overhead extraction polymerization-grade propylene product, and tower base stream delivers to 1# propylene refining tower, 1# propylene refining tower overhead vapor phase returns 2# propylene refining tower, and tower base stream is bromopropane product.
The present invention is further characterized in that: described propylene refining tower column bottom temperature is 10 ~ 90 DEG C, and preferred bottom temperature is 20 ~ 80 DEG C; Propylene refining tower tower reactor adopts low-pressure steam or hot water heating.
Present invention also offers a kind of separating device being beneficial to the low-carbon alkene of Product recycling, it is characterized in that: comprise depropanizing tower, demethanizing tower, described depropanizing tower upper end outlet is connected with demethanizing tower import, described demethanizing tower upper end is connected with pressure-swing absorption apparatus through demethanizing tower condenser and demethanizer reflux tank, lower end connects deethanizing column, described deethanizing column upper end connects acetylene hydrogenation reactor and ethylene polishing column, and lower end is connected with propine hydrogenator and propylene refining tower.
Described depropanizing tower is double tower system, comprise high pressure depropanizer and low pressure depropanizer, described high pressure depropanizer upper end outlet is connected with demethanizing tower import, lower end is connected with high pressure depropanizer reboiler, also be connected with low pressure depropanizer centre inlet simultaneously, described low pressure depropanizer upper end is provided with low pressure depropanizer condenser and low pressure depropanizer return tank, and lower end is provided with low pressure depropanizer reboiler.
Described high pressure depropanizer upper end is connected compressor by high pressure depropanizer condenser with high pressure depropanizer return tank, and described compressor is connected demethanizing tower by water cooler with demethanizing tower charging stock tank.
Described compressor is four sections of compressors.
Described deethanizing column upper end is connected with reaction product interchanger by deethanizing column condenser and deethanizer reflux tank, described reaction product interchanger connects acetylene hydrogenation reactor and ethylene polishing column feed exchanger simultaneously, and described ethylene polishing column feed exchanger connects ethylene polishing column.
Described deethanizing column lower end connects propine hydrogenator by interchanger, and described propine hydrogenator connects propylene refining tower by propylene refining tower feed exchanger.
Described propylene refining tower comprises 1# propylene refining tower and 2# propylene refining tower, and deethanizing column is connected with 2# propylene refining tower, and 2# propylene refining tower upper end connects propylene refining tower return tank, connects 1# propylene refining tower upper end side line opening for feed at the bottom of tower; 1# propylene refining column overhead discharge port is connected with 2# propylene refining tower bottom side line opening for feed.
Described ethylene polishing column and 2# propylene refining tower upper end are provided with condenser and return tank, and lower end is provided with reboiler.
Low-carbon alkene logistics of the present invention can be provided by usual sources.Such as, the low-carbon alkene mixture that formed of Naphtha cracking or oxygenatedchemicals catalyzed reaction.
In the process of oxygenatedchemicals producing olefinic hydrocarbons, oxygenate feed stream (being typically methyl alcohol or dme blend) is catalytically conveted to low-carbon alkene logistics.Low-carbon alkene logistics of the present invention comprises a large amount of ethene and propylene, and this low-carbon alkene logistics also includes hydrocarbons and hydrogen, carbon monoxide, carbonic acid gas, nitrogen, oxygen, the water etc. such as methane, ethane, acetylene, propane, propine, mixed c 4, mixing carbon five, mixing carbon six.Described water is the common by product be converted into as methanol oxidation in low carbon olefin hydrocarbon.In addition, low-carbon alkene logistics also includes the various oxygenated by-products of dme in interior difference amount, mainly due to conversion reaction not exclusively or side reaction cause.Described oxygenatedchemicals (the various oxygenatedchemicalss in low-carbon alkene logistics) comprises at least one organic compound, and the latter comprises at least one Sauerstoffatom, as fatty alcohol, ether, carbonyl compound (aldehyde, ketone, carboxylic acid, carbonate, ester etc.).
A kind of low-carbon alkene separation method being beneficial to Product recycling of the present invention.Be specially adapted to recovered ethylene, propylene from one or more mixtures comprised hydrogen, oxygen, nitrogen, carbon monoxide, carbonic acid gas, methane, ethane, ethene, acetylene, propane, propylene, cyclopropane, propine and propadiene (namely oxygenatedchemicals is converted into the own low-carbon alkene logistics removed after oxygenatedchemicals, water, C4 and more than C4 hydro carbons that olefine reaction system produces).It compared with prior art has following beneficial effect:
(1) the method for the invention and equipment can obtain the ethylene product of polymerization-grade and the propylene product of polymerization-grade.
(2) the method for the invention is cold in adopting with equipment is separated, and the service temperature that improve demethanizing tower is avoided the explosive combustible material such as oxygen and hydro carbons at low temperature and too assembles under having certain pressure and set off an explosion.
(3) the method for the invention and equipment take into account MTO(methanol-to-olefins) difference of gas composition and naphtha cracking gas, avoid using expensive and high to equipment requirements low ternperature separation process technology.
(4) the method for the invention and equipment are washed in separating technology to exist for current middle cold oil and are made because improve demethanizing tower temperature the problem that in demethanizer column overhead light gas, ethylene loss is large, on the basis of cold separation in same pursuit, the present invention is provided with pressure-swing absorption apparatus after demethanizing tower, the feature utilizing pressure-variable adsorption separating energy consumption low reclaims the ethene in light gas, improves the yield of ethene.
(5) in of the present invention, cold separation only introduces pressure-swing absorption apparatus in demethanizing system, does not use any absorption agent to promote being separated of ethene and methane; In the light Fuel gas component that demethanizing process can be obtained, the molar content of ethene is down to by 3.5% and is less than or equal to 1%.For current " middle cold oil is washed " or " precut+absorption " technique, because absorption agent consumption is large, need constantly to be heated in systems in which, condensation in the regenerative process of absorption agent, its energy consumption is fairly obvious; Secondly, absorption agent also can cause certain influence to subsequent separation system by follow-up separation regeneration, especially to propylene refining system, a large amount of cyclic absorption agent reduces the propylene content of propylene refining system feeding logistics, and this is equivalent to the separation requirement that in a disguised form improve propylene refining tower.The present invention, by the ethene of desorption after absorption is returned one section of compressor, avoids well and causes the impact on later separation unit because of design cold in demethanizing tower system.
(6) the method for the invention and equipment have good suitability to oxygenatedchemicals preparing low-carbon olefins or employing alternate manner preparing low-carbon olefins process.
Accompanying drawing explanation
The a part of Figure of description forming the present patent application is used to provide a further understanding of the present invention, and schematic description and description of the present invention, for explaining the present invention, does not form inappropriate limitation of the present invention.In the accompanying drawings:
The separation process figure of Fig. 1 for the benefit of low-carbon alkene of Product recycling;
Fig. 2 is the schematic flow sheet of pressure-swing absorption apparatus.
Embodiment
Embodiment 1
As depicted in figs. 1 and 2, a kind of low-carbon alkene separation method being beneficial to Product recycling, oxygenatedchemicals preparing low carbon alkene by catalytic conversion mixed gas, remove oxygenatedchemicals and water when pre-treatment after, except comprising ethene and propylene, also comprise one or more materials in hydrogen, oxygen, nitrogen, carbon monoxide, carbonic acid gas, methane, ethane, acetylene, propane, cyclopropane, propine and propadiene.Mixture after overdraft and heat exchange as low-carbon alkene logistics 1, be divided into vehicle repair major, wherein vapour phase is by pipeline 1-1, liquid phase enters high pressure depropanizer 2 by pipeline 1-2, high pressure depropanizer tower reactor reboiler 3 makes tower reactor logistics enter low pressure depropanizer 4 by steam heating to carry out being separated of C3 and C4, low pressure depropanizer tower reactor reboiler 5 makes bottom product 6 send into debutanizing tower system by steam or hot water heating to be further separated, also oxygenate conversion reactor entrance or fluidized catalytic cracker (FCC) can be sent into increase production alkene, low pressure depropanizer 4 overhead product enters low pressure depropanizer return tank 8 after low pressure depropanizer overhead condenser 7 cools, the liquid phase of low pressure depropanizer return tank 8 is divided into two strands, wherein one returns the tower top of low pressure depropanizer 4 as backflow, returns high pressure depropanizer 2 tower top after another strand and the recirculate mixing of high pressure depropanizer, the overhead vapor phase of high pressure depropanizer 2 enters high pressure depropanizer return tank 10 after high pressure depropanizer overhead condenser 9 condensation, the liquid phase of high pressure depropanizer return tank 10 returns high pressure depropanizer 2 tower top as after backflow and the liquid-phase mixing from low pressure depropanizer return tank 8, and the vapour phase of high pressure depropanizer return tank 10 is that C3 and below C3 component enters four sections of compressors 11 and boosts.
Logistics is forced into 2.0 ~ 4.0 MPa by four sections of compressors 11, logistics after compression sends into demethanizing tower charging stock tank 13 after water cooler 12 cools, the vapor phase stream of demethanizing tower charging stock tank 13 delivers to the top of demethanizing tower 14, and the liquid phase stream of demethanizing tower charging stock tank 13 also delivers to the middle and upper part of demethanizing tower 14.
Demethanizing tower tower reactor reboiler 21 adopts circulating water heating.Demethanizing tower 14 tower reactor is that C2 with C3 product stream 22 is sent into deethanizing column 23 and carried out being separated of C2 with C3.Demethanizing tower 14 overhead vapor phase is methane containing part ethene, enter demethanizer reflux tank 16 after the condensation of hydrogen stream stock-traders' know-how demethanizing tower condenser 15, the liquid phase of demethanizer reflux tank 16 returns the tower top of demethanizing tower 14 as backflow, and the vapour phase 17 of demethanizer reflux tank 16 is as the charging of pressure-swing absorption apparatus 18.
Methane containing part ethene, hydrogen stream stock 17 is as the charging of pressure-swing absorption apparatus 18, pressure-swing absorption apparatus 18 is that four pressure-swing absorber parallel combinations form, be respectively 18-1, 18-2, 18-3 and 18-4, for 18-1, during adsorption operations, valve A and B opens, valve C and D closes, logistics 17 enters pressure-swing absorption apparatus 18-1 through valve A and adsorbs, be not mainly hydrogen by adsorbent its component of light gas stream stock 19, methane and nitrogen, this light gas can be used as fuel gas and delivers to out-of-bounds, or deliver to hydrogen manufacturing pressure-swing absorption apparatus or membrane separation unit and purify further and obtain the highly purified hydrogen that molar content is more than 99.9%, when sorbent material reach capacity adsorptive capacity need carry out desorption manipulation time, valve A and B closes, valve C and D opens, first with the ethylene product gas obtained as sweep gas by the road 19-1 enter pressure-swing absorption apparatus, the foreign gas remained in absorbent particles gap is purged, sweep gas is discharged via pipeline 20, complete purge operations, valve-off C again, valve D is kept to open, by vacuumizing, desorption manipulation is carried out to the ethylene gas in pressure-variable adsorption agent, before the ethylene product gas that desorption obtains returns one section of compressor via pipeline 20, mix with the logistics of light olefin reaction gas.
Deethanizing column bottom reboiler 37 utilizes steam or circulating water heating.The gaseous mixture containing ethene, ethane and acetylene of deethanizing column 23 tower top output, cool through deethanizing column condenser 24 and enter deethanizer reflux tank 25 after condensation, the liquid phase of deethanizer reflux tank 25 returns the tower top of deethanizing column 23 as backflow, the vapour phase of deethanizer reflux tank 25 is the vapour mixture logistics containing ethene, ethane and acetylene.
If be less than 1ppm containing acetylene molar content in the vapour mixture logistics of ethene, ethane and acetylene, then the vapour mixture logistics containing ethene, ethane and acetylene after drying, directly enters ethylene polishing column 30 after ethylene polishing column feed exchanger 29 heat exchange, if containing ethene, in the vapour mixture product of ethane and acetylene, acetylene molar content is more than or equal to 1ppm, then will containing ethene, the vapour mixture logistics of ethane and acetylene is as the raw material of acetylene hydrogenation reactor 28, first acetylene hydrogenation reactor hydrogen make-up 27 is allocated into, acetylene hydrogenation reactor 28 top is entered after both mixing, what produce bottom acetylene hydrogenation reactor 28 contains ethene, the gaseous mixture of ethane is after reaction product interchanger 26 with the charging heat exchange of acetylene hydrogenation reactor 28, after entering ethylene polishing column feed exchanger 29 heat exchange after drying, enter ethylene polishing column 30 again.
Ethylene polishing column tower reactor reboiler 35 utilizes circulating water heating.At the bottom of ethylene polishing column 30 tower, the liquid phase ethane of output is delivered to outside device as Organic Chemicals, also can send into pressure-swing absorption apparatus recovered ethylene.
The gaseous mixture containing ethene, ethane, methane and hydrogen that ethylene polishing column 30 tower top produces, cool through ethylene polishing column condenser 31 and enter ethylene polishing column return tank 33 after condensation, the liquid phase of ethylene polishing column return tank 33 returns the tower top of ethylene polishing column 30 as backflow, the vapour phase of ethylene polishing column return tank 30 is the non-condensable gas of the ethylene polishing column backflow tank deck main hydrogen of non-condensable gas 32(and methane) after heat exchange, return three sections of compressors before, with alkali cleaning, wash after low-carbon alkene logistics mix.The ethylene molar content of ethylene polishing column 30 top side take-off is the ethene liquid-phase product 34 of more than 99.95%, delivers to outside device or preferentially enters polyethylene production device as polyethylene raw material.
Output at the bottom of deethanizing column 23 tower is containing the liquid mixture of propylene, propane, cyclopropane, propine and propadiene, if its propine molar content is less than 5ppm and propadiene molar content is less than 10ppm, then the liquid mixture containing propylene, propane, cyclopropane, propine and propadiene of output at the bottom of deethanizing column 23 tower is after interchanger 38 heat exchange, enter moisture eliminator and slough the minor amount of water of carrying secretly in C3 fraction, then after propylene refining tower feed exchanger 41 heat exchange, directly enter propylene refining tower 42, if its propine molar content is more than or equal to 5ppm or propadiene molar content when being more than or equal to 10ppm, then at the bottom of deethanizing column 23 tower out containing propylene, propane, cyclopropane, the liquid mixture of propine and propadiene is after interchanger 38 heat exchange, enter moisture eliminator and slough the minor amount of water of carrying secretly in C3 fraction, then allocate propine hydrogenator hydrogen make-up 39 into and export recycle stream with one propine hydrogenator and mix, enter propine hydrogenator 40 top, remove after propine and propadiene through shortening, bottom propine hydrogenator 40 out containing propylene, the mixture of propane is divided into two strands, one turns back to the entrance of propine hydrogenator 40, 2# propylene refining tower 42 is entered after another stock-traders' know-how and propylene refining tower feed exchanger 41 heat exchange.
The gaseous mixture containing propylene, propane that 2# propylene refining tower 42 tower top produces, 2# propylene refining tower return tank 45 is entered after the cooling of 2# propylene refining tower condenser 43 and condensation, the liquid phase of 2# propylene refining tower return tank 45 returns the tower top of 2# propylene refining tower 42 as backflow, the vapour phase of 2# propylene refining tower return tank 45 to be mole content be more than 99.6% propylene product 44, deliver to device outer or preferentially enter polypropylene production apparatus as pp material.2# propylene refining tower tower reactor reboiler 46 utilizes steam or circulating water heating.2# propylene refining tower 42 bottom product sends into 1# propylene refining tower 48.
1# propylene refining tower 48 overhead vapor phase directly returns as 2# propylene refining tower 42 bottom feed, 1# propylene refining tower 48 tower reactor reboiler 49 utilizes steam or circulating water heating, and at the bottom of 1# propylene refining tower 48 tower, the propane liquid-phase product 50 of output is delivered to outside device as Organic Chemicals.
In the present embodiment, the numerical parameter related to is: described high pressure depropanizer tower top working pressure is 3.2MPa, and high pressure depropanizer column bottom temperature is 40 DEG C; Described low pressure depropanizer tower top working pressure is 1.2MPa, and low pressure depropanizer column bottom temperature is 40 DEG C; Described demethanizer column overhead working pressure is 2.2MPa; Demethanizer column overhead temperature-40 DEG C; Described demethanizing tower column bottom temperature is 30 DEG C, and tower reactor adopts circulating water heating; Described pressure-variable adsorption agent is the modified activated carbon of supported copper, and adsorptive pressure is 2.2MPa, and adsorption temp is 30 DEG C; Described deethanizer overhead working pressure is 3.0MPa, and deethanizing column bottom temperature is 40 DEG C; Described ethylene polishing column tower top working pressure is 2.0MPa; Ethylene polishing column column bottom temperature is 30 DEG C; Ethylene polishing column tower reactor uses circulating water heating; Described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened from tower top to the 7th of the tower truth of a matter the piece of theoretical stage; Described propylene refining column overhead working pressure is 1.0MPa; Described propylene refining tower column bottom temperature is 80 DEG C.
Embodiment 2
Embodiment 2 is from the different of embodiment 1, and involved numerical parameter is: described high pressure depropanizer tower top working pressure is 1.8MPa, and high pressure depropanizer column bottom temperature is 100 DEG C; Described low pressure depropanizer tower top working pressure is 0.5MPa, and low pressure depropanizer column bottom temperature is 100 DEG C; Described demethanizer column overhead working pressure is 3.5MPa; Demethanizer column overhead temperature-45 DEG C; Described demethanizing tower column bottom temperature is-5 DEG C, and tower reactor adopts circulating water heating; Described pressure-variable adsorption agent is the modified activated carbon of supported copper, and adsorptive pressure is 3.5MPa, and adsorption temp is-5 DEG C; Described deethanizer overhead working pressure is 2.0MPa; Deethanizing column bottom temperature is 20 DEG C; Described ethylene polishing column tower top working pressure is 1.0MPa; Ethylene polishing column column bottom temperature is-30 DEG C; Ethylene polishing column tower reactor uses circulating water heating; Described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened from tower top to the 15th of the tower truth of a matter the piece of theoretical stage; Described propylene refining column overhead working pressure is 2.2MPa; Described propylene refining tower column bottom temperature is 20 DEG C.
Embodiment 3
Embodiment 3 is from the different of embodiment 1, and involved numerical parameter is: described high pressure depropanizer tower top working pressure is 3.8MPa, and high pressure depropanizer column bottom temperature is 20 DEG C; Described low pressure depropanizer tower top working pressure is 1.5MPa, and low pressure depropanizer column bottom temperature is 20 DEG C; Described demethanizer column overhead working pressure is 4.0MPa; Demethanizer column overhead temperature-43 DEG C; Described demethanizing tower column bottom temperature is 45 DEG C, and tower reactor adopts circulating water heating; Described pressure-variable adsorption agent is the modified activated carbon of supported copper, and adsorptive pressure is 3.0MPa, and adsorption temp is 50 DEG C; Described deethanizer overhead working pressure is 3.3MPa, and deethanizing column bottom temperature is 100 DEG C; Described ethylene polishing column tower top working pressure is 2.2MPa; Ethylene polishing column column bottom temperature is-40 DEG C; Ethylene polishing column tower reactor uses circulating water heating; Described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened from tower top to the 2nd of the tower truth of a matter the piece of theoretical stage; Described propylene refining column overhead working pressure is 2.5MPa; Described propylene refining tower column bottom temperature is 90 DEG C.
Embodiment 4
Embodiment 4 is from the different of embodiment 1, and involved numerical parameter is: described high pressure depropanizer tower top working pressure is 3.3MPa, and high pressure depropanizer column bottom temperature is 60 DEG C; Described low pressure depropanizer tower top working pressure is 0.8MPa, and low pressure depropanizer column bottom temperature is 60 DEG C; Described demethanizer column overhead working pressure is 2.0MPa; Demethanizer column overhead temperature 100 DEG C; Described demethanizing tower column bottom temperature is-15 DEG C, and tower reactor adopts circulating water heating; Described pressure-variable adsorption agent is the modified activated carbon of load silver, and adsorptive pressure is 2.7MPa, and adsorption temp is 10 DEG C; Described deethanizer overhead working pressure is 1.7MPa; Deethanizing column bottom temperature is 60 DEG C; Described ethylene polishing column tower top working pressure is 0.1MPa; Ethylene polishing column column bottom temperature is 30 DEG C; Ethylene polishing column tower reactor uses circulating water heating; Described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened from tower top to the 5th of the tower truth of a matter the piece of theoretical stage; Described propylene refining column overhead working pressure is 0.1MPa; Described propylene refining tower column bottom temperature is 10 DEG C.
Embodiment 5
As illustrated in fig. 1 and 2, comprise depropanizing tower 2, demethanizing tower 14, described depropanizing tower 2 upper end outlet is connected with demethanizing tower 14 import, described demethanizing tower 14 upper end is connected with pressure-swing absorption apparatus 18 through demethanizing tower condenser 15 and demethanizer reflux tank 16, lower end is connected with deethanizing column 23, described deethanizing column 23 upper end is connected with return tank 26, acetylene hydrogenation reactor 28 and ethylene polishing column 30, and lower end is connected with propine hydrogenator 40 and propylene refining tower 42.
Described depropanizing tower is double tower system, comprise high pressure depropanizer 2 and low pressure depropanizer 4, described high pressure depropanizer 2 lower end is connected with high pressure depropanizer reboiler 3, also be connected with low pressure depropanizer 4 centre inlet simultaneously, described low pressure depropanizer 4 upper end is provided with low pressure depropanizer condenser 7 and low pressure depropanizer return tank 8, and lower end is provided with low pressure depropanizer reboiler 5.
Described high pressure depropanizer 2 upper end is connected compressor 11 by high pressure depropanizer condenser 9 with high pressure depropanizer return tank 10, and described compressor 11 is connected demethanizing tower 14 by water cooler 12 with demethanizing tower charging stock tank 13.
Described compressor 11 is four sections of compressors.
Described deethanizing column 23 upper end is connected with reaction product interchanger 26 by deethanizing column condenser 24 and deethanizer reflux tank 25, described reaction product interchanger 26 connects acetylene hydrogenation device 28 and ethylene polishing column feed exchanger 29 simultaneously, and described ethylene polishing column feed exchanger 29 connects ethylene polishing column 30.
Described deethanizing column 23 lower end connects propine hydrogenator 40 by interchanger 38, and described propine hydrogenator 40 connects propylene refining tower by propylene refining tower feed exchanger 41.
Described propylene refining tower comprises 1# propylene refining tower and 2# propylene refining tower, and deethanizing column 23 is connected with 2# propylene refining tower 42, and 2# propylene refining tower 42 upper end connects 2# propylene refining tower return tank 45, connects 1# propylene refining tower upper end side line opening for feed at the bottom of tower; 1# propylene refining column overhead discharge port is connected with 2# propylene refining tower bottom side line opening for feed.
Described ethylene polishing column 30 and 2# propylene refining tower upper end are provided with condenser and return tank, and lower end is provided with reboiler.
Embodiment 6:
As table 1, method according to embodiment 1, low-carbon alkene reaction gas is after pre-treatment, with to adsorb through pressure-swing absorption apparatus and the crude ethylene gas that obtains of desorb mixes, be forced into 2.0MPa, and be cooled to raw material feeding high pressure depropanizer, the low pressure depropanizer as olefin separation system after 15 DEG C.Low pressure depropanizer bottom product sends into debutanizing tower, and high pressure depropanizer top product is forced into 3.2MPa and enters demethanizing tower after being cooled to-37 DEG C step by step.Product introduction deethanizing column at the bottom of demethanizer also carries out later separation, and the overhead condenser cryogen refrigeration of-40 DEG C, the components such as uncondensable hydrogen, methane and part ethene send into pressure-swing absorption apparatus recovered ethylene.Do not sent out-of-bounds by light constituents such as adsorbent hydrogen, methane as tail gas (fuel gas), or continue purifying hydrogen of hydrogen.The crude ethylene gas desorbed returns one section, compressor and mixes with pretreated low-carbon alkene logistics.Material balance is carried out to above technical process.
Embodiment 2-4 has effect similar to Example 1, and in the light Fuel gas component that demethanizing process can be obtained, the molar content of ethene is down to by 3.5% and is less than or equal to 1%, and run through absorption-rectifying coupling, ethene total recovery reaches 99.6%-99.8%.
Embodiment 1 calculation result listed by table 1:
| Stream names | Charging | Discharging at the bottom of depropanizing tower tower | Discharging at the bottom of demethanizer | Pressure-swing absorption apparatus charging | Pressure-variable adsorption emission | Return the recovered ethylene gas of compressor |
| Logistics number | 1 | 6 | 22 | 17 | 19 | 20 |
| Temperature/DEG C | 15 | 62.8 | 8.0 | 20 | 22 | 22 |
| Pressure/bar | 20 | 8.84 | 27.91 | 27.6 | 1.15 | 1.12 |
| Mass rate kg/h | 104664.7 | 12924.6 | 81729.1 | 10010.9 | 2346.2 | 7664.7 |
| Molar flow kmol/h | 3149.235 | 231.6241 | 182.2784 | 507.0549 | 205.088 | 301.9668 |
| Mole composition | ||||||
| H2 | 0.027344 | 0 | 0 | 0.17 | 0.398893 | 0.014259 |
| N2 | 0.002199 | 0 | 0 | 0.0137 | 0.032082 | 0.001147 |
| O2 | 9.63E-06 | 0 | 0 | 5.98E-05 | 0.00014 | 5.02E-06 |
| CO | 0.002663 | 0 | 0 | 0.0165 | 0.03884 | 0.001388 |
| CH4 | 0.056323 | 0 | 8.47E-07 | 0.35 | 0.518916 | 0.234956 |
| C2H4 | 0.507883 | 0 | 0.574634 | 0.422539 | 0.010447 | 0.702422 |
| C2H6 | 0.012155 | 0 | 0.014575 | 0.006202 | 0.000153 | 0.010311 |
| C3H6 | 0.296498 | 0.014379 | 0.381687 | 0.020392 | 0.000504 | 0.033899 |
| C3H8 | 0.026141 | 0.051084 | 0.029039 | 0.000971 | 2.40E-05 | 0.001614 |
| C4H8 | 0.062039 | 0.842836 | 6.19E-05 | 0 | 0 | 0 |
| C4H10 | 0.00477 | 0.064829 | 1.98E-06 | 0 | 0 | 0 |
| C5H10 | 0.001976 | 0.026872 | 2.14E-09 | 0 | 0 | 0 |
Claims (13)
1. one kind is beneficial to the low-carbon alkene separation method of Product recycling, it is characterized in that: the low-carbon alkene logistics transformed by oxygenatedchemicals is by sending into depropanization system after pre-treatment, demethanizing tower is sent into after the cooling of depropanization system overhead product, demethanizer column overhead only uses propylene refrigerant to cool, overhead vapor phase sends into pressure-swing absorption apparatus recovered ethylene, the crude ethylene gas reclaimed mixes with the logistics of low-carbon alkene reaction gas before being back to one section of compressor; Specifically comprise the following steps:
(1) logistics of oxygenatedchemicals preparing low-carbon olefin by conversion is after one section of compressor and two sections of compressor compresses, heat exchange, in succession removing oxygenatedchemicals and the pre-treatment such as sour gas and water, form mixture flow with the vapour phase from ethylene polishing column top return tank, after three sections of compressor boost, cooling and dehydrations, enter high pressure depropanizer;
(2) gaseous mixture of high pressure depropanizer tower top generation, compressed and cooling after enter demethanizing tower charging stock tank, in charging stock tank, vehicle repair major enters demethanizing tower top respectively as feed stream, after demethanizer overhead gas cooling out, liquid phase stream returns demethanizing tower, vapor phase stream enters pressure-swing absorption apparatus, and adsorptive pressure is 2.2 ~ 3.5MPa, and adsorption temp is-5 ~ 50 DEG C;
(3) the pressure-variable adsorption agent in pressure-swing absorption apparatus has good selectivity to ethene, light gas methane in gas mixture can be separated with crude ethylene gas with hydrogen, through sorbent material selective adsorption and the crude ethylene gas of desorb gained is back to one section of compressor mixes with the logistics of low-carbon alkene reaction gas, then enter high pressure depropanizer after a series of process;
(4) high pressure depropanizer tower bottoms is delivered to low pressure depropanizer and is separated further, and low pressure depropanizer overhead product returns high pressure depropanizer, and bottom product is used for reclaiming or being separated further;
(5) component at the bottom of demethanizer is delivered to deethanizing column and is carried out being separated of C2 and C3;
(6), after the C2 gaseous mixture that deethanizer overhead produces enters return tank cooling, liquid phase stream returns deethanizing column, and vapor phase stream is sent to hydrogenation or directly sent into ethylene polishing column;
(7) ethylene polishing column carries out being separated of ethene and ethane, ethylene polishing column top lateral line withdrawal function ethene liquid-phase product, and ethylene polishing column bottom product is ethane liquid-phase product;
(8) be C3 liquid mixture at the bottom of deethanizing column tower, send to hydrogenation or directly enter propylene refining tower;
(9) vapour phase of propylene refining tower return tank of top of the tower is propylene vapor-phase product, and propylene refining tower bottom product is propane liquid-phase product.
2. the low-carbon alkene separation method being beneficial to Product recycling according to claim 1, it is characterized in that: the described gas entering pressure-swing absorption apparatus is divided into two strands by pressure-variable adsorption, wherein be not mainly hydrogen, methane and nitrogen by adsorbent light component, this light gas can be used as fuel gas and delivers to out-of-bounds; Or deliver to hydrogen manufacturing pressure-swing absorption apparatus or membrane separation unit and purify further and obtain the highly purified hydrogen that molar content is more than 99.9%; Described by the ethene that adsorbs by desorption rear portion as sweep gas, before rest part is back to one section of compressor, mix with the logistics of low-carbon alkene reaction gas.
3. the low-carbon alkene separation method being beneficial to Product recycling according to claim 2, it is characterized in that: the pre-treatment of described low-carbon alkene logistics mainly comprises to be carried out primary dewatering, heat exchange, remove oxygenatedchemicals, enters soda-wash tower and remove sour gas after one section of compressor and two sections of compressor pressurizes to 1.8 ~ 3.8 MPa, carries out drying and dehydrating afterwards; Described pretreated low-carbon alkene logistics sends into high pressure depropanizer through three sections of compressor boost, cooling and dehydration, and high pressure depropanizer overhead gas enters four sections of compressors and is compressed to 2.0 ~ 4.0 MPa further; The alkene mixture of four sections of described compressor outlets enters demethanizing tower charging stock tank after cooler cooling.
4. the low-carbon alkene separation method being beneficial to Product recycling according to claim 3, is characterized in that: described demethanizing tower charging stock tank top vapour phase out and bottom liquid phase are out respectively as two bursts of chargings of demethanizing tower; In demethanizing tower, not only containing methane, hydrogen, nitrogen and oxygen in overhead vapor phase, also containing part C2 and a small amount of C3, this gas enters demethanizer column overhead return tank after the cooling of demethanizer column overhead condenser, the vapour phase of demethanizer reflux tank top enters pressure-swing absorption apparatus, and the liquid of bottom is then as the backflow of demethanizing tower; At the bottom of demethanizer, liquid phase stream is through reboiler, and reboiler top gas is back to demethanizing tower, and bottom liquid is then delivered to deethanizing column and carried out being separated of C2 with C3.
5. the low-carbon alkene separation method being beneficial to Product recycling according to claim 4, it is characterized in that: described deethanizer overhead vapour phase enters deethanizer overhead return tank after cooling, the liquid-phase reflux of deethanizer reflux tank, to deethanizer overhead, directly sends into ethylene polishing column when acetylene molar content is less than 1ppm in the vapour phase of deethanizer reflux tank after super-dry and cooling; Enter acetylene hydrogenation reactor when its acetylene molar content is more than or equal to 1ppm and carry out hydrogenation reaction, the gaseous mixture containing ethene, ethane that acetylene hydrogenation reactor produces, after cooling and drying, send into ethylene polishing column; The gaseous mixture that described ethylene polishing column tower top produces enters ethylene polishing column return tank after cooling and condensation; The liquid phase of ethylene polishing column return tank returns ethylene polishing column tower top as backflow, and the vapour phase of ethylene polishing column return tank is, before the non-condensable gas of hydrogen and methane returns three sections of compressors, mix with alkali cleaning and the low-carbon alkene logistics after washing; Ethylene polishing column top lateral line withdrawal function ethene liquid-phase product, ethylene polishing column bottom product is ethane liquid-phase product, also tower reactor crude pentafluoroethane can be sent into pressure-swing absorption apparatus recovered ethylene.
6. the low-carbon alkene separation method being beneficial to Product recycling according to claim 5, it is characterized in that: be C3 liquid mixture at the bottom of described deethanizing column tower, after pressurization, heat exchange and drying, enter propylene refining tower when its propine molar content is less than 5ppm and propadiene molar content is less than 10ppm; After pressurization, heat exchange and drying, enter propine hydrogenator when its propine molar content is more than or equal to 5ppm or propadiene molar content is more than or equal to 10ppm and carry out hydrogenation reaction, next reaction product enters propylene refining tower; The gaseous mixture that described propylene refining column overhead produces enters propylene refining tower return tank after cooling and condensation, the liquid phase of propylene refining tower return tank returns propylene refining column overhead as backflow, the vapour phase of propylene refining tower return tank is propylene vapor-phase product, and propylene refining tower bottom product is propane liquid-phase product.
7. the low-carbon alkene separation method being beneficial to Product recycling according to claim 6, is characterized in that: described high pressure depropanizer tower top working pressure is 1.8 ~ 3.8 MPa, and high pressure depropanizer column bottom temperature is 20 ~ 100 DEG C; Described low pressure depropanizer tower top working pressure is 0.5 ~ 1.5MPa, and low pressure depropanizer column bottom temperature is 20 ~ 100 DEG C; Described high and low pressure depropanizing tower tower reactor low-pressure steam or hot water heating.
8. the low-carbon alkene separation method being beneficial to Product recycling according to claim 7, is characterized in that: described demethanizer column overhead working pressure is 2.0 ~ 4.0MPa, and demethanizer column overhead temperature is more than or equal to-45 DEG C; Described demethanizing tower column bottom temperature is-15 ~ 45 DEG C, and tower reactor adopts circulating water heating.
9. the low-carbon alkene separation method being beneficial to Product recycling according to claim 8, is characterized in that: described pressure-variable adsorption agent is the modified activated carbon of supported copper or silver.
10. the low-carbon alkene separation method being beneficial to Product recycling according to claim 9, it is characterized in that: described deethanizer overhead working pressure is 1.7 ~ 3.3MPa, deethanizing column bottom temperature is 20 ~ 100 DEG C, and deethanizing column tower reactor uses low-pressure steam or hot water heating.
The 11. low-carbon alkene separation methods being beneficial to Product recycling according to claim 10, it is characterized in that: described ethylene polishing column tower top working pressure is 0.1 ~ 2.2MPa, ethylene polishing column column bottom temperature is-40 ~ 30 DEG C, and ethylene polishing column tower reactor uses circulating water heating; Described ethylene polishing column is from top lateral line withdrawal function ethene liquid-phase product, and lateral line withdrawal function mouth is opened at 2nd ~ 15 pieces of theoretical stages from tower top to the tower truth of a matter.
12. according to the low-carbon alkene separation method being beneficial to Product recycling one of claim 1-11 Suo Shu, it is characterized in that: described propylene refining column overhead working pressure is 0.1 ~ 2.5MPa, propylene refining tower divides cascade towers to operate, C3 mixture enters 2# propylene refining tower, this column overhead extraction polymerization-grade propylene product, tower base stream delivers to 1# propylene refining tower, and 1# propylene refining tower overhead vapor phase returns 2# propylene refining tower, and tower base stream is bromopropane product; Described propylene refining tower column bottom temperature is 10 ~ 90 DEG C, and propylene refining tower tower reactor adopts low-pressure steam or hot water heating.
13. 1 kinds of separating devices being beneficial to the low-carbon alkene of Product recycling, it is characterized in that: comprise depropanizing tower, demethanizing tower, described depropanizing tower upper end outlet is connected with demethanizing tower import, described demethanizing tower upper end is connected with pressure-swing absorption apparatus through demethanizing tower condenser and demethanizer reflux tank, described pressure-swing absorption apparatus is that the pressure-swing absorber parallel combinations of at least one forms, described demethanizing tower lower end connects deethanizing column, described deethanizing column upper end connects acetylene hydrogenation reactor and ethylene polishing column, lower end is connected with propine hydrogenator and propylene refining tower,
Described depropanizing tower is double tower system, comprise high pressure depropanizer and low pressure depropanizer, described high pressure depropanizer upper end outlet is connected with demethanizing tower import, lower end is connected with high pressure depropanizer reboiler, also be connected with low pressure depropanizer centre inlet simultaneously, described low pressure depropanizer upper end is provided with low pressure depropanizer condenser and low pressure depropanizer return tank, and lower end is provided with low pressure depropanizer reboiler;
Described high pressure depropanizer upper end is connected compressor by high pressure depropanizer condenser with high pressure depropanizer return tank, and described compressor is connected demethanizing tower by water cooler with demethanizing tower charging stock tank; Described compressor is four sections of compressors;
Described deethanizing column upper end is connected with reaction product interchanger by deethanizing column condenser and deethanizer reflux tank, described reaction product interchanger connects acetylene hydrogenation reactor and ethylene polishing column feed exchanger simultaneously, and described ethylene polishing column feed exchanger connects ethylene polishing column; Described deethanizing column lower end connects propine hydrogenator by interchanger, and described propine hydrogenator connects propylene refining tower by propylene refining tower feed exchanger;
Described propylene refining tower comprises 1# propylene refining tower and 2# propylene refining tower, and deethanizing column is connected with 2# propylene refining tower, and 2# propylene refining tower upper end connects propylene refining tower return tank, connects 1# propylene refining tower upper end side line opening for feed at the bottom of tower; 1# propylene refining column overhead discharge port is connected with 2# propylene refining tower bottom side line opening for feed; Described ethylene polishing column and 2# propylene refining tower upper end are provided with condenser and return tank, and lower end is provided with reboiler.
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| WO2016204977A1 (en) | 2015-06-15 | 2016-12-22 | Uop Llc | Processes and apparatuses for recovery of ethylene from hydrocarbons |
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