CN107138025A - The low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized - Google Patents

The low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized Download PDF

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CN107138025A
CN107138025A CN201710396428.6A CN201710396428A CN107138025A CN 107138025 A CN107138025 A CN 107138025A CN 201710396428 A CN201710396428 A CN 201710396428A CN 107138025 A CN107138025 A CN 107138025A
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methanol
low
cold
newly
heat exchanger
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CN107138025B (en
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李国庆
廖藤藤
钟国添
欧春松
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South China University of Technology SCUT
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South China University of Technology SCUT
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1456Removing acid components
    • B01D53/1462Removing mixtures of hydrogen sulfide and carbon dioxide
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1425Regeneration of liquid absorbents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/14Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
    • B01D53/1493Selection of liquid materials for use as absorbents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2252/00Absorbents, i.e. solvents and liquid materials for gas absorption
    • B01D2252/20Organic absorbents
    • B01D2252/202Alcohols or their derivatives
    • B01D2252/2021Methanol

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention belongs to field of energy and chemical technology, the low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized is disclosed.The technique is by middle pressure flash column lateral line withdrawal function methanol rich solution and bottom methanol rich solution through the laggard CO of reducing pressure by regulating flow2Regenerator, is adjusted to advanced newly-increased hydraulic turbine expansion work decrease temperature and pressure, then enters newly-increased low-temperature circulating working fluid heat exchanger recovery cryogenic cold energy, then enters CO2Regenerator;And by hot recycling tower most poor methanol and CO2Regenerator bottom methanol rich solution changes the cold advanced newly-increased forecooler of most poor methanol that is adjusted to and cooled, the CO after being exchanged heat through methanol loop cooler2Methanol rich solution advanced newly-increased low-temperature circulating working fluid heat exchanger in regenerator bottom reclaims cryogenic cold energy, and then most poor methanol changes cold by richness/poor methanol heat exchanger again with methanol rich solution.Present invention process can significantly reclaim work(and cold, with significant economic benefit.

Description

The low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized
Technical field
The invention belongs to field of energy and chemical technology, and in particular to the low temperature that a kind of pressure energy and cold energy high efficiente callback are utilized Methanol cleaning process.
Background technology
It is a kind of gas purification work developed by German Linde Co and LURGI the fifties in last century that low-temp methanol, which is washed, Skill.It does the acidic components in lyosoption, removing unstripped gas with low-temp methanol, thus is widely used in synthesis ammonia, natural gas The industry such as desulfurization and town gas purification.In ammonia synthesizing industry, the first transformed unit of the raw gas from (coal) gas unit processed CO shift reaction CO is converted into CO to greatest extent2H is rich in produce2Conversion gas (wherein CO molar concentrations ≯ 0.4%), then conversion gas enters low-temp methanol and washed, the characteristics of can be strong to acidic components dissolving using low-temp methanol, removes therein CO2And H2The acid impurities such as S (make CO2Concentration ≯ 20ppm, H2S concentration ≯ 0.1ppm;The CO of removing2Or send urea cellular manufacture to urinate Element is discharged or remanufacture dry ice etc., rich in H2S sour gas Ze Songzhi sulphur workshop section production sulphur or sulfuric acid), Ran Houjin Methanation or liquid nitrogen washing unit, in the CO and CO of removing remaining2(its oxycarbide total content ≯ 10ppm) deammoniation synthesis unit afterwards Produce liquefied ammonia.
The capital equipment that low-temp methanol is washed is H2S absorption towers, CO2Absorption tower, CO2Regenerator, hot recycling tower, methanol-water point From tower and middle pressure flash column.Wherein, absorption tower is operated to strengthen adsorption effect using cryogenic high pressure, and regenerator is due to that need to seethe with excitement State desorbs sour gas from rich solution, therefore uses low pressure operation, therefore methanol solvate is from lean solution to rich solution, and from There is the phenomenon of decompression into the cyclic process of lean solution in rich solution, such as come from middle pressure flash column side line and bottom is rich in CO respectively2With CO2/H2S methanol, which is just depressurized, enters CO2Regenerator, the build-up of pressure loss of energy.With certain 450,000 tons/year of synthetic ammonia installation low temperature first Alcohol is washed exemplified by unit, and middle pressure flash column extracts methanol rich solution 108t/h and 206t/h out from side line and bottom respectively, they from 1.42MPag is depressurized to 0.09MPag, and difference pressuring loss reaches 1.33MPa.If reclaiming pressure energy or generating or the drive of this two fluids The dynamic hot recycling tower most power-equipment such as poor methanol pump, then can not only increase income electric energy (or saving power consumption), can also therefore produce Low temperature cold, or for this unit or outer defeated to other workshop sections's (such as synthesis ammonia and space division), the compression to reduce device, which is freezed, steams Vapour is consumed.In addition, low-temp methanol washes unit and changes the existing configuration of cold flow and is:Come from CO2Regenerator bottom reabsorbs section bottom Rich in H2S methanol rich solution it is secondary (so that above-mentioned 450,000 tons/year of synthetic ammonia installation low-temp methanols wash workshop section as an example, its flow 421t/ H, about -25.8 DEG C) directly change cold with coming from the most poor methanol (415t/h, about 100 DEG C) of hot recycling tower, most poor methanol is cooled down CO is sent to -7.3 DEG C2Absorption tower, itself is warming up to 77.4 DEG C and enters hot recycling tower, and this is typical high cold low use.If can be with following The most poor methanol of ring hot water or 100 DEG C of recirculated water or air precooling, then it is replaceable go out about -13.1 DEG C~-25.8 DEG C of equivalent it is cold Measure about 5279kw, or the personal reduction present apparatus cooling load or be transferred to neighbouring cold-trap.
The content of the invention
For the defect of above prior art energy loss, it is an object of the invention to provide a kind of pressure energy and cold energy are high Imitate the low-temp methanol washing process recycled.
The object of the invention is achieved through the following technical solutions:
The low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized, including following process step:
(1) by middle pressure flash column lateral line withdrawal function methanol rich solution and bottom methanol rich solution through the laggard CO of reducing pressure by regulating flow2Regenerator, Advanced newly-increased hydraulic turbine expansion work decrease temperature and pressure is adjusted to, then enters newly-increased low-temperature circulating working fluid heat exchanger recovery low temperature Cold energy, then enters CO2Regenerator;
(2) by hot recycling tower most poor methanol and the CO after the heat exchange of methanol loop cooler2Regenerator bottom methanol rich solution is straight Connected richness/poor methanol heat exchanger and change cold, and the advanced newly-increased forecooler cooling of most poor methanol was adjusted to, through methanol loop cooler CO after heat exchange2Methanol rich solution advanced newly-increased low-temperature circulating working fluid heat exchanger in regenerator bottom reclaims cryogenic cold energy, then most poor Methanol changes cold by richness/poor methanol heat exchanger again with methanol rich solution.
Further, increasing hydraulic turbine and low-temperature circulating working fluid heat exchanger in step (1) newly does not influence methanol rich solution to enter CO2Temperature, the pressure and other parameters of regenerator.
Further, the forecooler increased newly in step (2) is equal with the thermic load of low-temperature circulating working fluid heat exchanger, to ensure Methanol rich solution enters hot recycling tower after adjustment, and most poor methanol enters CO2The temperature on absorption tower does not change.
Further, the low-temperature circulating working fluid heat exchanger increased newly described in step (1) and step (2) refer to 4~10 DEG C it is cool Water- to-water heat exchanger.
Further, the forecooler increased newly described in step (2) refers to circulate water precooler.
In above-mentioned adjustment, the cryogenic cold energy cemented out by low-temperature circulating working medium (such as 10~4 DEG C cold water) can be sent to conjunction outside Ammonification or air separation unit (or other are adjacent to cold-trap), to reduce their energy consumption for cooling.And the pressure energy reclaimed can contemplate orphan Island generation mode online (wherein side line hydraulic turbine is contemplated that substitution motor does the power of hot recycling tower most poor methanol pump, because Effective turbine is exerted oneself substantially suitable with the shaft work of pump).
The present invention is based on following principle:
(1) throttling is permanent enthalpy also constant entropy pressure reduction, and the pressure energy of fluid is consumed in height irreversible procedure, used instead It is flat then not only reclaimed pressure energy, and the temperature of fluid is greatly reduced, it is returned into former throttling discharge state, then taken Concurrent heating heats up, and this just creates chance for outer defeated cold energy.So hydraulic turbine is to kill two birds with one stone for choke valve, height has not only been reclaimed The pressure energy of energy fluid, also creates cold energy.
(2) in existing procedure, low-temp methanol rich solution secondary (about -25.8 DEG C) directly with most poor methanol once (about 100 DEG C) It is the so-called high exergy loss process of the second law of thermodynamics to change cold, and high irreversible degree causes the cold energy of methanol rich solution seriously to drop Level is used, even if most poor methanol is finally cooled to -7.3 DEG C by it, low-temperature end heat transfer temperature difference is still up to 18.5 DEG C.It is adjusted to most poor Methanol first changes cold with methanol rich solution again by recirculated water precooling, is also to replace high-quality (about -13.1 DEG C of cold energy with equivalent low-quality energy consumption ~-25.8 DEG C).Therefore above-mentioned adjustment be follow the second law of thermodynamics it " high energy height use, low energy it is low use " energy step by step using original What reason was proposed.
Relative to prior art, the invention has the advantages that and beneficial effect:
(1) pressure of the current middle pressure flash column side line through throttle loss and the bottomsstream has been reclaimed by hydraulic turbine Power energy and first section high temperature heat, and the high-quality cold energy equal with output work numerical value is created, pairing ammonification is this kind of to be needed using big It is highly beneficial for the technique for measuring steam or electricity refrigeration.
(2) the simply inexpensive recirculated water once consumed with recirculated water precooling most poor methanol, and exchange for is high value Cryogenic cold energy output (such as 4~10 DEG C of cold water or the cycle fluid of other lower temperatures), compared to most poor methanol once about 100 DEG C, with circulating hot water or demineralized water precooling, the present invention does not consume recirculated water not only, another many on the contrary income, therefore the present invention With high yield.
(3) present invention only increases hydraulic turbine and heat exchanger newly on pipeline, coordinates the measures such as bypass adjustment to ensure to enter The parameter that associated fluid enters downstream units is strictly constant, therefore will not be to CO2Absorption tower, CO2The behaviour of regenerator, hot recycling tower Make to constitute influence, yield and purity that low-temp methanol washes unit product purified gas are not interfered with naturally.
(4) (also middle pressure flash column side line and bottom distillate methanol rich solution and CO for three bursts of logistics of the invention2Regenerator bottom Distillate methanol rich solution) cold output be to realize that therefore their route does not change by intermediate cycle medium (such as 4~10 cold water) Become, operation is safe and reliable.
Brief description of the drawings
Fig. 1 is the existing low-temp methanol washing process flow chart of comparative example of the present invention;
The low-temp methanol washing process flow chart that Fig. 2 utilizes for the pressure energy of the embodiment of the present invention and cold energy high efficiente callback;
Numbering is described as follows in figure:1- raw materials/synthesis gas heat exchanger;2- unstripped gas ammonia coolers;3- converts qi leel flow container;4- Raw material/synthesis gas heat exchanger;5-H2S absorption towers;6-CO2Absorption tower;7-CO2Absorption tower Intermediate Heat Exchanger;8- methanol loops are cooled down Device;9-H2S absorption towers feed pump;Flash column is pressed in 10-;11-H2S absorption towers feed cooler;12- recycle compressors are imported and exported Heat exchanger;13- recycle compressors charging point flow container;14- recycle compressors;15- recycle compressors export water cooler;16- ammonia is cold Device;17- choke valves;18- choke valves;19-CO2Regenerator;20-CO2Absorption tower feed cooler;21- hot recycling tower feed pumps; 22- richnesses/poor methanol heat exchanger;23- hot recycling towers;24- prewashing methanol heaters;25- hot recycling tower top water coolers;26- heat is again Raw tower reboiler;27- methanol/water fractionating columns;28- methanol/water fractionating column reboilers;29- water/methanol fractionation tower bottom sewage cooling Device;30- hydraulic turbines;31- low-temperature circulating working fluid heat exchangers;32- hydraulic turbines;33- low-temperature circulating working fluid heat exchangers;34- is low Warm cycle fluid heat exchanger;35- circulates water precooler.
Embodiment
With reference to embodiment and accompanying drawing, the present invention is described in further detail, but embodiments of the present invention are not limited In this.
Comparative example
This comparative example is existing low-temp methanol washing process, its process chart as shown in figure 1, specific process step is as follows:
Unstripped gas (3.0Mpa, 40 DEG C) from converter unit enters raw material/synthesis gas heat exchanger 1 and unstripped gas ammonia cooler 2 After cooling, conversion qi leel flow container 3 is entered back into, the process condensate isolated delivers to conversion section process condensate stripper, gas Body carrys out gas with recycle compressor charging point flow container 13 and mixed, and raw material/synthesis gas heat exchanger 4 is entered after a small gangs of methanol is sprayed into, Subsequently enter H2Micro constitutent such as NH in the prewashing section on S absorption towers 5, gas3With HCN by from H2S absorption towers feed cooler 11 a small amount of cold methanol washing absorption, after the prewashing methanol of bottom of towe exchanges heat through prewashing methanol heater 24, delivers to hot recycling tower 23 Regenerated, hot recycling tower sets hot recycling tower reboiler 26;Gas enters H through a liter gas tower tray2The main absorber portion on S absorption towers 5, H in gas2S and CO2By from CO2The rich CO on absorption tower 62Methanol washing absorption is clean, then rich in H2S/CO2Methanol is sent to Middle pressure flash column 10 presses flash distillation in carrying out.Tower top sweet gas enters CO2The lower absorbent section on absorption tower 6, with coming that tower top is introduced Self-heating regenerator 23, through richness/shell-side of poor methanol heat exchanger 22 and CO2The pipe side of absorption tower feed cooler 20 is cooled to -51.7 DEG C cold poor methanol carry out counter-current absorption, CO is set in the middle part of absorption tower2Absorption tower Intermediate Heat Exchanger 7, tower top purified gas and raw material/ Synthesis gas heat exchanger 4, raw material/synthesis gas heat exchanger 1 are sent to demethanization or liquid nitrogen washing unit after exchanging heat;CO2The bottom of absorption tower 6 2.8Mpa, -22 DEG C of rich CO2Methanol fractions are through H2S absorption towers charging pump 9 delivers to H2As absorbent at the top of S absorption towers 5, remaining Methanol flow to it is middle pressure flash column 10 top flash zone.In the filler of the bottom flash zone of middle pressure flash column 10, rich H2S/ CO2Valuable H in methanol2With least a portion of CO2Flash off, in order to reduce the total amount of circulation compressed gas, two strands of flashed vapours Flowed up after mixing, with coming from H on the tower tray of the middle pressure bottom flash zone of flash column 102The methanol of S absorption towers bottom feed pump Counter current contacting, absorbs most of CO therein2, saliva is gone out through recycle compressor 14, recycle compressor successively after flashed vapour extraction Cooler 15 enters recycle compressor after entering the pipe side of recycle compressor inlet outlet heat exchanger 12, cooling recycle compressor exit gas Charging point flow container 13;The middle pressure lateral line withdrawal function methanol rich solution of flash column 10 is cooled in ammonia cooler 16, after being depressurized through choke valve 18 It is divided into two strands, one larger delivers to CO2The low pressure flash section at the top of regenerator 19, CO2The operating pressure of tower on regenerator 19 For 0.12Mpa or so, therefore, most of pure CO2Product flash distillation is discharged;Another gang of richness CO2Methanol enters CO2Regeneration On the regenerator section top tower tray of tower 19, the pure CO of another stock is discharged2, then methanol be used as reabsorb medium flow downward, Absorb the CO risen2Contained sulfide in gas.Rich H from middle pressure flash column 10 bottom2S/CO2Methanol is through choke valve 17 Two strands are also classified into after decompression, one larger enters CO2The CO of regenerator 192Regenerate on pars infrasegmentalis filler, CO2On a small quantity simultaneously The H flashed off2S and COS are discharged herein, and flashed vapour is flowed up, in CO2By containing CO on the tower tray of regenerator section top2Methanol is again Absorb sulfide therein, CO2Gas continues up flowing, enters CO through a liter gas tower tray2Regenerator 19 low pressure flash section is and low Press the CO of flash zone2Product mix, with delivering to urea plant as product after raw material heat exchange after tower top outflow.From CO2Regeneration The CO of tower 192Regenerator section be rich in H2S/CO2Methanol enters CO2Regenerator 19 is mainly reabsorbed in section, at the same time, in coming from Another strand of methanol of the bottom of flash column 10 is pressed also to enter CO after being depressurized through choke valve 182Regenerator 19 mainly reabsorbs the upper of section. CO2The bottom of regenerator 19 reabsorbs the rich H of section bottom2S methanol is pressurizeed by hot recycling tower feed pump 21, in methanol loop cooler 8 In shell-side and richness/poor methanol heat exchanger 22 with after most poor methanol once exchanges heat, into hot recycling tower 23.From CO2Regenerator is fed The rich H of pump 212S methanol and from H2The rich H of the prewashing of S absorption towers 5 section2S methanol respectively enters the hot recycling of hot recycling tower 23 section, rich H2S Methanol regenerates, water enriching section of the methanol steam part from the bottom of hot recycling tower 23 completely through methanol steam air lift, remaining Tower overhead gas from methanol/water fractionating column 27, methanol/water fractionating column sets methanol/water fractionating column reboiler 28, and bottom of towe is set Water/methanol fractionation tower bottom sewage cooler 29 to sewage disposal.Methanol steam/gas at the top of the hot recycling of hot recycling tower 23 section is mixed Compound passes through a series of cooling procedures, and methanol condensed is got off.First, by the shell-side of prewashing methanol heater 24, heating comes from H2The cold prewashing richness H on S absorption towers 52S methanol, then after the shell-side water cooling of hot recycling tower top water cooler 25, most of methanol condensed Get off, into the reflux section of the bottom of hot recycling tower 23, the remaining sour gas that do not coagulate is drawn from reflux section top, is delivered to after cooling Sulfuric acid apparatus;The condensate liquid isolated flows back to the bottom reflux section of hot recycling tower 23.
Embodiment
The present embodiment has carried out following improvement compared to comparative example flow:
(1) the rich H of pressure flash column 10 bottom in2S/CO2Methanol (206t/h, 1.42MPag, -38.4 DEG C) is through choke valve 18 (206t/h, 0.09MPag, -61.4 DEG C) enters CO after throttling2Regenerator 19, is adjusted to the rich H of middle pressure flash column 10 bottom2S/ CO2After the advanced newly-increased hydraulic turbine 32 of methanol (206t/h, 1.42MPag, -38.4 DEG C), expansion work (206t/h, 0.09MPag, -64.7 DEG C) enter newly-increased low-temperature circulating working medium (such as 4~10 DEG C cold water) heat exchanger 33 again, released cold quantity, by Heat is warming up to before adjustment consistent rear (206t/h, 0.09MPag, -61.4 DEG C) and enters CO2Regenerator 19.In order to ensure CO2Regenerator 19 operation is not affected because of the adjustment, and newly-increased hydraulic turbine 32 and low-temperature circulating working medium cooler 33 are respectively provided with accordingly Regulation measure (is such as bypassed).
(2) (108t/h, 1.42MPag-38.4 after the pressure lateral line withdrawal function methanol rich solution of flash column 10 cools through ammonia cooler 16 in DEG C) enter choke valve 17 and throttle, then (108t/h, 0.09MPag, -57.05 DEG C) enters CO2Regenerator 19, is adjusted to methanol rich solution From ammonia cooler 16 after out rear (108t/h, 1.42MPag-38.4 DEG C), advanced newly-increased hydraulic turbine 30, expansion work (108t/h, 0.09MPag, -64.7 DEG C) enters newly-increased low-temperature circulating working medium (such as 4~10 DEG C cold water) heat exchanger 31 and reclaims cold again Can, it is heated to be warming up to and enters CO with adjustment preceding consistent rear (108t/h, 1.42MPag-57.05 DEG C)2Regenerator 19.In order to ensure CO2 The operation of regenerator 19 is unaffected, and newly-increased hydraulic turbine 30 and low-temperature circulating working fluid heat exchanger 31 are respectively provided with regulation measure.
In addition, can also stop ammonia cooler 16, the lateral line withdrawal function methanol rich solution conceded from middle pressure flash column 10 directly enters newly-increased Hydraulic turbine 30, not only can may be omitted with (or reduction) downstream cryogenic circulation industrial because fluid temperature (F.T.) is higher and does work more The cold output of matter cooler 31, makes the cold obtained by turbine personal (if low-temperature circulating working medium cooler 31 in device Refrigeration duty be more than ammonia cooler 16, ammonia cooler 16 can stop;If the refrigeration duty of low-temperature circulating working medium cooler 31 is less than ammonia cooler 16, ammonia cooler 16 then sets bypass).
(3) CO is come from2The methanol rich solution of the bottom of regenerator 19 secondary (421t/h ,~-25.8 DEG C) is directly with going out self-heating again The most poor methanol (415t/h ,~100 DEG C) of raw tower 23 changes cold, is cooled to -7.3 DEG C and send CO2Absorption tower feed cooler 20, Itself it is warming up to 77.4 DEG C and enters hot recycling tower 23.It is adjusted to methanol rich solution secondary (421t/h ,~-25.8 DEG C) advanced newly-increased low Warm cycle fluid (such as 4~10 cold water) heat exchanger 34, after released cold quantity is warming up to -13.1 DEG C, walks former flow through richness/poor methanol Heat exchanger 22 is warming up to 77.4 DEG C and enters hot recycling tower 23;And most poor methanol (415t/h ,~100 DEG C) then advanced newly-increased recirculated water Forecooler 35 is cooled to after 88.7 DEG C, and former flow of going further cools to -7.3 DEG C through richness/poor methanol heat exchanger 22 and send CO2Absorption tower is entered Expect cooler 20.In the adjustment, the cold end heat transfer temperature difference of richness/poor methanol heat exchanger 22 is reduced to 5.8 DEG C by 18.5 DEG C, while hot Load is reduced, and equivalence has been transferred to circulation water precooler 35 and low-temperature circulating working fluid heat exchanger 34, therefore CO2Absorption tower 6 and heat are again The operation of raw tower 23 is unaffected.
Compared with comparative example, the present embodiment has increased two hydraulic turbines 30 and 32, three low-temperature circulating working fluid heat exchangers newly 31st, 33 and 34, a circulation water precooler 35.They are arranged on corresponding pipeline, coordinate the regulation measures such as bypass, not to tower Operation produce influence.
So that certain 450,000 tons/year of synthetic ammonia installation low-temp methanol is washed as an example, embodiment efficiency income is as shown in table 1~3.
The turbine of table 1 acting income *
* calculated based on turbine isentropic efficiency of expansion 75%.
The integrated cold energy income of the turbine of table 2
The secondary cold output of the methanol rich solution of table 3
From result above:
(1) pressure the bottomsstream of flash column 10 is depressurized to 0.09MPag through hydraulic turbine from 1.42MPag in, swollen by constant entropy Swollen efficiency 75% calculates acting 396kW, and the middle survey line distillate of pressure flash column 10 is depressurized to through hydraulic turbine from 1.42MPag 0.09MPag, calculates acting 186kW by isentropic efficiency of expansion 75%, adds up to 582kw.
(2) turbine expansion cooling is coordinated, the middle pressure bottom of towe of flash column 10 and side stream harvest about -60 DEG C of cold energy respectively 396kW and 186kW, adds up to 582kw;While average -19 DEG C cold energy 5279kw of methanol rich solution secondary recovery.Three measures are amounted to Reclaim cold energy 5861kw.
Parameter before and after the present embodiment and the adjustment of the main heat transmission equipment of comparative example is as shown in table 4.
Parameter before and after the adjustment of the main heat transmission equipment of table 4
Above-described embodiment is preferably embodiment, but embodiments of the present invention are not by above-described embodiment of the invention Limitation, other any Spirit Essences without departing from the present invention and the change made under principle, modification, replacement, combine, simplification, Equivalent substitute mode is should be, is included within protection scope of the present invention.

Claims (5)

1. the low-temp methanol washing process that a kind of pressure energy and cold energy high efficiente callback are utilized, it is characterised in that including following processing step Suddenly:
(1) by middle pressure flash column lateral line withdrawal function methanol rich solution and bottom methanol rich solution through the laggard CO of reducing pressure by regulating flow2Regenerator, adjustment For advanced newly-increased hydraulic turbine expansion work decrease temperature and pressure, then enter newly-increased low-temperature circulating working fluid heat exchanger and reclaim low temperature cold Can, then enter CO2Regenerator;
(2) by hot recycling tower most poor methanol and the CO after the heat exchange of methanol loop cooler2Regenerator bottom methanol rich solution directly passes through Richness/poor methanol heat exchanger changes cold, the advanced newly-increased forecooler cooling of most poor methanol is adjusted to, after being exchanged heat through methanol loop cooler CO2Methanol rich solution advanced newly-increased low-temperature circulating working fluid heat exchanger in regenerator bottom reclaims cryogenic cold energy, then most poor methanol with Methanol rich solution changes cold by richness/poor methanol heat exchanger again.
2. the low-temp methanol washing process that a kind of pressure energy according to claim 1 and cold energy high efficiente callback are utilized, its feature It is:Increasing hydraulic turbine and low-temperature circulating working fluid heat exchanger in step (1) newly does not influence methanol rich solution to enter CO2The temperature of regenerator Degree, pressure parameter.
3. the low-temp methanol washing process that a kind of pressure energy according to claim 1 and cold energy high efficiente callback are utilized, its feature It is:The forecooler increased newly in step (2) is equal with the thermic load of low-temperature circulating working fluid heat exchanger, to ensure that methanol is rich after adjustment Liquid enters hot recycling tower, and most poor methanol enters CO2The temperature on absorption tower does not change.
4. the low-temp methanol washing process that a kind of pressure energy according to claim 1 and cold energy high efficiente callback are utilized, its feature It is:The low-temperature circulating working fluid heat exchanger increased newly described in step (1) and step (2) refers to 4~10 DEG C of cold water heat exchangers.
5. the low-temp methanol washing process that a kind of pressure energy according to claim 1 and cold energy high efficiente callback are utilized, its feature It is:The forecooler increased newly described in step (2) refers to circulate water precooler.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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WO2022108985A1 (en) * 2020-11-17 2022-05-27 Saudi Arabian Oil Company Amine absorber configuration
CN113532191A (en) * 2021-07-22 2021-10-22 华亭煤业集团有限责任公司 Optimized heat exchange network of low-temperature methanol washing system
WO2023176572A1 (en) * 2022-03-16 2023-09-21 三菱重工業株式会社 Carbon dioxide recovery system

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