CN1188375C - Method for demethanizing in ethylene production - Google Patents
Method for demethanizing in ethylene production Download PDFInfo
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- CN1188375C CN1188375C CNB011183594A CN01118359A CN1188375C CN 1188375 C CN1188375 C CN 1188375C CN B011183594 A CNB011183594 A CN B011183594A CN 01118359 A CN01118359 A CN 01118359A CN 1188375 C CN1188375 C CN 1188375C
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
- F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
- F25J3/0252—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of hydrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2200/00—Processes or apparatus using separation by rectification
- F25J2200/78—Refluxing the column with a liquid stream originating from an upstream or downstream fractionator column
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J2210/00—Processes characterised by the type or other details of the feed stream
- F25J2210/12—Refinery or petrochemical off-gas
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P30/00—Technologies relating to oil refining and petrochemical industry
- Y02P30/40—Ethylene production
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Abstract
The present invention belongs to the technical field of chemical industry. Initial separation and direct heat exchange are carried out to heavy and light components in cracking gas after compression, drying and heat exchange by a multi-stage counterflow rectifying tower, and cracking gas whose light components are partially eliminated is led in a demethanizing tower for further separation. The demethanizing tower is operated from-72 to-75 DGE C, tail gas on the top is used for recovering ethene by an absorption tower AD1, and purified products of oxygen can be obtained by further treating residual methane and hydrogen gas after ethene is recovered. Absorbed and loaded ethene is recovered after being desorbed. The present invention has the characteristics of reduced energy consumption in the operation of a demethanizing system and reduced investment for equipment.
Description
The invention belongs to chemical technology field, particularly a kind of technology novel method that is used for the ethylene production demethanizing.
The demethanizing process is the important component part of ethylene production.Wherein demethanizing process mainly comprises two steps: the pre-cold-peace demethanizing of raw material.The deep cooling demethanizing process that is used at present producing generally can be divided into methods such as high-pressure process, low-pressure process and ARS.The main operational condition of high-pressure process is high pressure precooling (3.4MPa), high pressure demethanizing (2.94MPa), and the main operational condition of low-pressure process is high pressure precooling (3.4Mpa) and low-pressure methane removing (0.59MPa).Low-pressure methane removing can improve the relative volatility of methane and ethene, greatly reduces minimum stripping amount and minimum reflux ratio (lp system is 0.1-0.2, and high-pressure system is 0.8～1.0), thereby has saved energy.But the low-pressure methane removing flow process is not suitable for all cracking stocks, only is applicable to the CH of cracking product
4/ C
2H
4Bigger occasion.
ARS technology, promptly advanced isolation technique (Advanced Recovery System) are the advanced person's of the common exploitation of Stone Webster company and Mobil chemical company olefin recovery novel procesies.This technology adopts condensation separator, before demethanizing tower, with the hydrogen in the splitting gas, methane is as much as possible to be separated, demethanizing tower can be operated under comparatively high temps, thereby cancelled-101 ℃ ethene cryogen, this is the maximum characteristics and the advantage of this technology.
Compare with high-pressure process, although ARS technology and low-pressure methane removing technology have certain energy-conserving action, but in the industrial implementation process, all need extremely low temperature (generally maintaining-99 ℃), consume a large amount of cryogens, the corresponding apparatus material need adopt the 3.5Ni steel or stainless steel, and pipe material also will all be used stainless steel.There is two-phase flow in total system simultaneously, need adopt bigger line size in order to reduce pressure drop, and these factors have restricted further developing of low-pressure methane removing technology.
The objective of the invention is to propose a kind of method that is used for the ethylene production demethanizing, adopt high pressure conditions (2.94MPa) demethanizing, make it have the operation energy consumption that reduces the demethanizing system, the characteristics that reduce facility investment for overcoming the weak point of prior art.
The present invention proposes a kind of method that is used for the ethylene production demethanizing, it is characterized in that, may further comprise the steps:
(1) through the splitting gas after the compression drying heat exchange, cooling enters first rectifying tower DT1 bottom in the demethanizing tower intermediate reboiler; The DT1 rectifying tower is divided into up and down two independent parts of A, B, and the vapour phase extraction of bottom rectifying section B is cooled to-37 ℃ ~-38 ℃ with-40 ℃ of propylene refrigerants again after being cooled to-26 ℃ ~-30 ℃ with deethanizing column still liquid in the charging chiller, enter separator SP2 separation; The lime set that separator is told is sent bottom B rectifying back to and is partly done backflow; Uncooled gas enters top A rectifying part as the gas that boils again, the liquid of top rectifying A also enters bottom B rectifying and partly does backflow: like this, tower still still liquid by the first rectifying tower mass-and heat-transfer enters demethanizing tower DA-301, and the top gas phase of first rectifier rectifying A part is through ice chest CD1 and the condensation of ethene cryogen, enter vapor-liquid separation tank SP1, gas phase enters the tower still of second rectifying tower DT2 bottom rectifying C part, and liquid phase then enters first rectifying tower DT1 top A part as refluxing;
The cat head gas phase of (2) second rectifying tower DT2 bottom C rectifying is separated in separating tank SP3 after ice chest CD2 heat exchange and ethene cryogen are cooled to-72 to-75 ℃, liquid enters bottom C rectifying and partly does backflow, the tower still that gas phase then enters the second rectifier D rectifying part gas that boils again.The second rectifying tower DT2 top rectifying D part cat head gas phase is separated in separating tank SP4 after ice chest CD3 heat exchange cooling, and liquid enters the second rectifying tower DT2 top and does backflow;
The liquid phase that (3) first rectifying tower DT1 come out the bottom enters demethanizing tower DA-301, and demethanizing tower is-72 to-75 ℃ of operation operations, and top tail gas has the ethylene recovery of 10%-15% approximately.
The top method for recovering tail gas in the 3rd step of the present invention adopts absorption tower AD1 to reclaim, and the methane and the hydrogen that come out in AD1 top, absorption tower are further handled and obtained purified hydrogen product; The ethene that comes out in the still liquid of demethanizing tower bottom and desorption tower DA1 top enters the further separation of C of deethanizing column
2, C
3
The characteristics of this flow process are:
1, use multi-stage countercurrent contact rectification tower:
(a) once balance of separating tank in traditional demethanizing technology has been made into the repeatedly balance of counter current contact, heavy component ethene is further separated with light component methane;
(b) gas-liquid direct contact heat transfer and mass transfer in tower avoided in the ARS technology that gas-liquid two-phase flows in the plate-fin heat exchanger heat exchanger channels, and heat-transfer effect is reduced, and wayward, shortcoming such as turndown ratio is little;
(c) in rectifying tower, the gas-to-liquid contact area is far longer than two-phase contact area in the ice chest, can obtain better separating effect.
2. behind demethanizing tower and ice chest, adopted solvent absorption process.The main effect on absorption tower is the ethene that reclaims in the demethanizing tower tail gas, and the consumption of absorption agent and energy consumption are all very low.By regulating the consumption of absorption agent, can make the loss of ethene be reduced to minimum, improved the yield of ethene.Adopt this technology, make that methane and the hydrogen more than 70% leaves demethanizing tower before demethanizing tower, and the trim the top of column temperature brings up to-75 ℃, thereby reduce the thermal load of demethanizing cat head condenser, cryogen consumption is obviously descended;
3. in the precooling stage, improved the separation temperature of methane hydrogen, the energy expenditure of ethene cryogen has been reduced significantly cancelled-101 ℃ ethene cryogen, the demand of cryogen is shifted to the cryogen of higher level; Because cold shifts to higher rank, and low temperature resistant steel consumption amount is reduced;
4. this flow process is owing to the no longer strict control of demethanizer column overhead ethylene content, strengthen operational stability.Because flow process requires greatly to reduce to ethylene content in the tail gas, demethanizing tower no longer is " bottleneck " of expanding production and transforming, and unnecessary ethene all can reclaim fully by absorption tower efficiently.
Effect of the present invention is:
The material that rectifying tower DT1 comes out the bottom in the method for the present invention enters demethanizing tower DA-301, because the content of methane hydrogen reduces significantly in the charging, and the load of demethanizing tower is reduced, and reduces the reflux ratio of demethanizing tower simultaneously, the required cold of demethanizing cat head reduces, and has saved ethene cryogen consumption.And absorption-desorption process then utilizes a large amount of low-grade quenched water of having more than needed in a large amount of quenching processes.Make the energy utilization of ethylene process more reasonable, reduce the ethylene production energy consumption significantly.Adopt this technology can make present 700-800Kcal/ ton ethene be reduced to 400-500Kcal/ ton ethene.Adopt simultaneously this flow process can reduce former flow process ethene machine, propylene machine load each about 50% and 80%, the throughput of former flow process is increased substantially.
Fig. 1 is a process flow diagram of the present invention.
A kind of method embodiment that is used for the ethylene production demethanizing that the present invention proposes.This technical process may further comprise the steps as shown in Figure 1:
(1) through the splitting gas after the compression drying heat exchange, cooling enters first rectifying tower DT1 bottom in the demethanizing tower intermediate reboiler; The DT1 rectifying tower is divided into up and down two independent parts of A, B, and the vapour phase extraction of bottom rectifying section B is cooled to-37 ℃ ~-38 ℃ with-40 ℃ of propylene refrigerants again after being cooled to-26 ℃ ~-30 ℃ with deethanizing column still liquid in the charging chiller, enter separator SP2 separation; The lime set that separator is told is sent bottom B rectifying back to and is partly done backflow; Uncooled gas enters top A rectifying part as the gas that boils again, the liquid of top rectifying A also enters bottom B rectifying and partly does backflow: like this, tower still still liquid by the first rectifying tower mass-and heat-transfer enters demethanizing tower DA-301, and the top gas phase of first rectifier rectifying A part is through ice chest CD1 and the condensation of ethene cryogen, enter vapor-liquid separation tank SP1, gas phase enters the tower still of second rectifying tower DT2 bottom rectifying C part, and liquid phase then enters first rectifying tower DT1 top A part as refluxing:
The cat head gas phase of (2) second rectifying tower DT2 bottom C rectifying is separated in separating tank SP3 after ice chest CD2 heat exchange and ethene cryogen are cooled to-72 ℃, liquid enters bottom C rectifying and partly does backflow, the tower still that gas phase then enters the second rectifier D rectifying part gas that boils again.The second rectifying tower DT2 top rectifying D part cat head gas phase is separated in separating tank SP4 after ice chest CD3 heat exchange cooling, and liquid enters the second rectifying tower DT2 top and does backflow;
The liquid phase of coming out in (3) first rectifying tower DT1 bottom enters demethanizing tower DA-301, and demethanizing tower is-72 ℃ of operation operations, and top tail gas has 12% ethene to enter absorption tower AD1 to reclaim approximately;
(4) methane and the hydrogen that come out at the top of absorption tower AD1 enters pressure swing adsorption system (PSA) and obtains purified hydrogen product.The ethene that comes out in the still liquid of demethanizing tower bottom and desorption tower DA1 top enters the further separation of C of ethane tower
2, C
3
Cracking is produced 300000 tons of design datas per year and is used this flow process and carried out preliminary analog calculation at solar oil.
Above-mentioned technical process significant parameter embodiment 1 is as follows:
First rectifying tower: a tower: 5 of theoretical stages, temperature: at the bottom of the cat head-40.6 ℃ tower :-17.1 ℃
B tower: 5 of theoretical stages, temperature: at the bottom of the cat head-72.3 ℃ tower :-71.3 ℃
The second rectifying tower c tower: 5 of theoretical stages, temperature: at the bottom of the cat head-116.3 ℃ tower :-105.3 ℃
D tower: 5 of theoretical stages, temperature: at the bottom of the cat head-130.8 ℃ tower :-130.7 ℃
Demethanizing tower theoretical stage: 43 temperature: at the bottom of the cat head-76.1 ℃ tower: 7.1 ℃
Absorption tower theoretical stage: 15 temperature: at the bottom of the cat head-30 ℃ tower :-31.2 ℃
2 tons of solvents of the consumption of solvent/ton ethene
Analytic Tower theoretical stage: 15 temperature: at the bottom of 15 ℃ of towers of cat head: 5 ℃
Splitting gas comes out the hydrogen more than 80%, methane separation before advancing demethanizing tower in this technology.Hydrogen in the charging, methane content only are respectively about 0.8% and 10%, thereby greatly reduce the load of demethanizing tower.
The demethanizing precooling zone isolating gas-to-liquid contact of rectifying tower substituting disposable in the while novel process, the gaseous stream that makes cold liquid phase stream and heat is through sufficient mass transfer and heat transfer, heavy components such as light component such as methane one hydrogen and ethene are further separated, the methane content that enters demethanizing tower is reduced significantly.Because the first rectifying tower bottom rectifying section has removed heavy component in advance, the flow that enters precooling zone is reduced, also reduced energy expenditure simultaneously, save energy about about 30%.Under identical power loss situation, wherein can save ethylene refrigerant about 30%, propylene refrigerant about 35%.
Above-mentioned technical process significant parameter embodiment 2 is as follows:
First rectifying tower: a tower: 6 of theoretical stages, temperature: at the bottom of the cat head-40.6 ℃ tower :-17.1 ℃
B tower: 6 of theoretical stages, temperature: at the bottom of the cat head-72.3 ℃ tower :-71.3 ℃
The second rectifying tower c tower: 6 of theoretical stages, temperature: at the bottom of the cat head-116.3 ℃ tower :-105.3 ℃
D tower: 6 of theoretical stages, temperature: at the bottom of the cat head-130.8 ℃ tower :-130.7 ℃
Demethanizing tower theoretical stage: 43 temperature: at the bottom of the cat head-76.1 ℃ tower: 7.1 ℃
Absorption tower theoretical stage: 15 temperature: at the bottom of cat head-30 tower :-31.2 ℃
3 tons of solvents of the consumption of solvent/ton ethene
Analytic Tower theoretical stage: 15 temperature: at the bottom of 15 ℃ of towers of cat head: 5 ℃
Splitting gas can come out the hydrogen more than 81%, methane separation before advancing demethanizing tower.Hydrogen in the charging, methane content only are respectively about 0.75% and 9%.Save energy about about 30.5%.Under identical power loss situation, wherein can save ethylene refrigerant 31%, propylene refrigerant 35.5%.
Above-mentioned technical process significant parameter embodiment 3 is as follows:
First rectifying tower: a tower: 6 of theoretical stages, temperature: at the bottom of the cat head-40.6 ℃ tower :-17.1 ℃
B tower: 6 of theoretical stages, temperature: at the bottom of the cat head-72.3 ℃ tower :-71.3 ℃
The second rectifying tower c tower: 6 of theoretical stages, temperature: at the bottom of the cat head-116.3 ℃ tower :-105.3 ℃
D tower: 6 of theoretical stages, temperature: at the bottom of the cat head-130.8 ℃ tower :-130.7 ℃
Demethanizing tower theoretical stage: 50 temperature: at the bottom of the cat head-76.1 ℃ tower: 7.1 ℃
Absorption tower theoretical stage: 20 temperature: at the bottom of the cat head-30 ℃ tower :-31.2 ℃
3 tons of solvents of the consumption of solvent/ton ethene
Analytic Tower theoretical stage: 20 temperature: at the bottom of 15 ℃ of towers of cat head: 5 ℃
Splitting gas can come out the hydrogen more than 80.5%, methane separation before advancing demethanizing tower.Hydrogen in the charging, methane content only are respectively about 0.82% and 9.1%.Save energy about about 31%.Under identical power loss situation, wherein can save ethylene refrigerant 29%, propylene refrigerant 34%.
Claims (2)
1, a kind of method that is used for the ethylene production demethanizing.It is characterized in that, may further comprise the steps:
(1) through the splitting gas after the compression drying heat exchange, cooling enters first rectifying tower (DT1) bottom in the demethanizing tower intermediate reboiler; (A, B) two independent parts about first rectifying tower is divided into, the vapour phase extraction of bottom rectifying section (B), in the charging chiller, be cooled to-37 ℃ ~-38 ℃ again after being cooled to-26 ℃ ~-30 ℃ with deethanizing column still liquid, enter separator (SP2) and separate with-40 ℃ of propylene refrigerants; The lime set that separator is told is sent bottom (B) rectifying back to and is partly done backflow; Uncooled gas enters top (A) rectifying part as the gas that boils again, the liquid of top rectifying (A) also enters bottom (B) rectifying and partly does backflow: like this, tower still still liquid by the first rectifying tower mass-and heat-transfer enters demethanizing tower (DA-301), and the top gas phase of the first rectifier rectifying (A) part is through ice chest (CD1) and the condensation of ethene cryogen, enter vapor-liquid separation tank (SP1), gas phase enters the tower still of second rectifying tower (DT2) bottom rectifying (C) part, and liquid phase then enters first rectifying tower (DTI) top (A) part as refluxing;
The cat head gas phase of (2) second rectifying tower (DT2) bottom (C) rectifying through ice chest (CD2) heat exchange with in separating tank (SP3), separate after the ethene cryogen is cooled to-72 to-75 ℃, liquid enters bottom (C) rectifying and partly does backflow, the tower still that gas phase then enters second rectifier (D) the rectifying part gas that boils again, second rectifying tower (DT2) top rectifying (D) part cat head gas phase is separated in separating tank (SP4) after ice chest (CD3) heat exchange cooling, and liquid enters second rectifying tower (DT2) top and does backflow;
The liquid phase of coming out in (3) first rectifying tower (DT1) bottom enters demethanizing tower (DA-301), and demethanizing tower is-72 to-75 ℃ of operation operations, and top tail gas has the ethylene recovery of 10%-15%.
2, the method that is used for the ethylene production demethanizing as claimed in claim 1.It is characterized in that the top method for recovering tail gas in described the 3rd step adopts absorption tower (Ad1) to reclaim, concrete steps are: the methane and the hydrogen that come out in top, absorption tower (Ad1), and further handle and obtain purified hydrogen product; The ethene that comes out in the still liquid of demethanizing tower bottom and desorption tower (DA1) top enters the further separation of C of deethanizing column
2, C
3
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011183594A CN1188375C (en) | 2001-05-25 | 2001-05-25 | Method for demethanizing in ethylene production |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB011183594A CN1188375C (en) | 2001-05-25 | 2001-05-25 | Method for demethanizing in ethylene production |
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| CN1326913A CN1326913A (en) | 2001-12-19 |
| CN1188375C true CN1188375C (en) | 2005-02-09 |
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Cited By (1)
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| WO2020069246A1 (en) * | 2018-09-28 | 2020-04-02 | Uop Llc | Pressure swing adsorption integration in steam cracking ethylene plants |
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| CA2543195C (en) * | 2003-10-30 | 2009-02-10 | Fluor Technologies Corporation | Flexible ngl process and methods |
| CN100404482C (en) * | 2005-09-23 | 2008-07-23 | 中国石油大学(北京) | Hydration, film and deep cooling separation combined process for separating ethene cracking gas |
| CN100430351C (en) * | 2005-09-23 | 2008-11-05 | 中国石油大学(北京) | Secondary hydration and deep cooling separation combined process for separating ethene cracking gas |
| CN100404483C (en) * | 2005-09-23 | 2008-07-23 | 中国石油大学(北京) | Hydration, pressure swing adsorption and deep cooling combined process for separating ethene cracking gas |
| CN109867579B (en) * | 2017-12-01 | 2021-11-16 | 中国石化工程建设有限公司 | Device and method for improving start-up operation of demethanizer of ethylene plant |
| US11320196B2 (en) | 2017-12-15 | 2022-05-03 | Saudi Arabian Oil Company | Process integration for natural gas liquid recovery |
-
2001
- 2001-05-25 CN CNB011183594A patent/CN1188375C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020069246A1 (en) * | 2018-09-28 | 2020-04-02 | Uop Llc | Pressure swing adsorption integration in steam cracking ethylene plants |
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