CN103585856B

CN103585856B - A kind of pressure swing absorption process of many backflows

Info

Publication number: CN103585856B
Application number: CN201310558091.6A
Authority: CN
Inventors: 张东辉; 张正旺; 鲁东东; 银醇彪
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2013-11-11
Filing date: 2013-11-11
Publication date: 2016-08-24
Anticipated expiration: 2033-11-11
Also published as: CN103585856A; CN104815521A; CN104815521B

Abstract

The invention discloses the pressure swing absorption process of a kind of many backflows, during utilize portioned product gas to be back to tower tower to go displacement, improve product purity and yield further.Each adsorption tower include absorption, equal pressure drop, displacement, along putting, inverse put, evacuation, all press liter, a step in the boosting of light component or number step, cyclic switching works, and is interrupted or continuous print output at least two product gas.Present invention can apply to binary gas phase system and the separation of ternary gas phase system mixed gas, obtain two pure components or two pure components and the gas products of an enrichment intermediate species by the method for pressure-variable adsorption.

Description

A kind of pressure swing absorption process of many backflows

Technical field

The present invention relates to a kind of pressure-variable adsorption separating binary and the separation method of three-element mixed gas body, particularly one contain The pressure-changeable gas-adsorption separation method of multiple reflow step.

Background technology

Pressure swing adsorption, as a kind of novel separation method, is widely used in the Separation & Purification field of gas. Along with going deep into of research, its application is also constantly expanding.From air, such as isolate nitrogen, oxygen, from synthesis gas Isolated hydrogen, carbon monoxide, isolate methane, hydrogen, carbon dioxide etc. from natural gas.Pressure swing adsorption technique is profit With gas with various adsorbance on the sorbent and the difference of the rate of adsorption, High Pressure Absorption, the principle of low pressure desorbing separates mixed Close gas.

Tradition pressure-changeable gas-adsorption separation method is typically only capable to obtain a kind of product, it is desirable to simultaneously to difficult absorbed component with Easily absorbed component mostly uses the method for multistage pressure-variable adsorption or introduces displacement step.Multiple process makes the investment of device entirety become Obtaining huge, operation becomes complicated；Permissible to two kinds of product gas by introducing after displacement step, but can only be to increase adsorption tower Number or auxiliary equipment such as surge tank reach the method improving two kinds of product purities, and replace tail gas and typically again to reclaim use To improve yield.

Summary of the invention

It is an object of the invention to provide the pressure swing adsorption technique of a kind of improvement, overcome above-mentioned present in prior art asking Topic, reduces system dynamics consumption and fixed investment expense.

The technical purpose of the present invention is achieved by following technical proposals:

The pressure swing absorption process of a kind of many backflows, uses adsorption tower parallel way to be connected, and arranges slow in pipeline Rush tank, vacuum pump and compressor, pending unstrpped gas is passed through surge tank, vacuum pump and compression between adsorption tower in parallel Machine realize gas at the bottom of the tower top or tower of adsorption tower in parallel between multi-reflow, with realize component in unstrpped gas point From, obtain with the tower top at adsorption tower and obtain heavy constituent at the bottom of the tower of light component, adsorption tower.

The one in activated alumina, Kiselgel A, activated carbon or molecular sieve is loaded in described adsorption tower.

Separation for binary composition.Using double tower paralleling model, the flow chart of two tower pressure-variable adsorption separation air is the most attached Shown in Fig. 1:

First adsorption tower (being designated A in figure) is in parallel with the second adsorption tower (being designated B in figure), at the first adsorption tower and former On pipeline between material gas import, the first control valve V-1 is set, the pipeline between the second adsorption tower and raw material gas inlet sets Put the second control valve V-2；

Tower top at described first adsorption tower is connected, on both connecting lines by the tower top of pipeline and the second adsorption tower 5th control valve V-5 is set；Tower top at described first adsorption tower receives device (not marking in figure) by pipeline with light component It is connected, and the 3rd control valve V-3 is set on pipeline,；Tower top at described second absorption tower is received with light component by pipeline Device (not marking in figure) is connected, and arranges the 4th control valve V-4 on pipeline；

It is being connected with vacuum pump by pipeline at the bottom of the tower of described first adsorption tower, and the 6th control valve V-is being set on pipeline 6, it is connected with compressor also by pipeline, and the 8th control valve V-8 is set on pipeline；Logical at the bottom of the tower of described second absorption tower Cross pipeline to be connected with vacuum pump, and the 7th control valve V-7 is set on pipeline, be connected with compressor also by pipeline, and at pipe 9th control valve V-9 is set on road；

Described vacuum pump is connected with surge tank by pipeline respectively with compressor.

When carrying out pressure-variable adsorption, use arranged side by side two adsorption tower, by the easy adsorbed gas in unstripped gas through absorption Tower Adsorption Concentration, is difficult to absorbed component and flows out from tower top, obtain multiple product gas, and each circulation of its technological process includes inhaling Attached, blood pressure lowering, evacuate, feed, boost:

(1) feed entrance point described in is a certain position charging in the middle of adsorption tower, and optimum chooses gas phase composition and raw material in tower The point charging that gas composition is equal.Charging can select lower pressure column low pressure feed and the two ways of high-pressure tower high pressure charging.

(2) adsorption process described in forces partial reflux displacement to be difficult to absorbed component for using heavy constituent at the bottom of tower so that it is from Overhead extraction part is rinsed for lower pressure column boosting as light product section.

Above-mentioned adsorption process is particularly as follows: pressure feed gas is entered in the middle part of adsorption tower A by imported valve, simultaneously from absorption The adsorption production that is difficult to of tower B top extraction is partly refluxed to adsorption tower A top, by vacuum pump to easily absorption bottom adsorption tower A Component carries out desorbing；Tower A and tower B is attached boost pressure, and the method all pressed can use overhead, at the bottom of tower at the bottom of tower Mode；It is passed through adsorption tower A after the easy absorbed component obtained in vacuum buffer tank being pressurizeed it is boosted；After reaching pressure It is difficult to absorbed component by metathesis from tower A top extraction, stops displacement step when easy absorbed component will penetrate from tower top； Drop pressure is carried out by connecting tower A and tower B；Pressure obtains easy absorbed component with vacuum pump evacuation after reducing and sends into vacuum buffer Tank, part is as easy absorbed component product extraction simultaneously.

For the separation of ternary component, use multitower paralleling model, the wherein flow chart of eight tower pressure-variable adsorption separation air As shown in Figure 3:

Described first adsorption tower (A tower) tower top is connected with light component surge tank by the 5th pipeline, and in the 5th pipeline Control valve V5-A is set；The tower top of remaining seven adsorption tower is connected by respective connecting line and the 5th pipeline, and is each connecting Adapter arranges control valve (V5 B to V5 H) on road；

Described first adsorption tower (A tower) tower top is connected with intermediate species surge tank by the 7th pipeline, and at the 7th pipeline In control valve V7 A is set；The tower top of remaining seven adsorption tower is connected by respective connecting line and the 7th pipeline, and each Control valve (V7 B to V7 H) is set on connecting line；

Described first adsorption tower (A tower) tower top is connected by control valve V6 A and the 6th pipeline, remaining seven adsorption tower Tower top is connected with the 6th pipeline by respective control valve (V6 B to V6 H)；

It is connected by the 4th pipeline and the first compressor at the bottom of described first adsorption tower tower, and control is set in the 4th pipeline Valve V4 A；Described first compressor is connected with heavy constituent surge tank；By respective connecting line at the bottom of the tower of remaining seven adsorption tower It is connected with the 4th pipeline, and control valve (V4 B to V4 H) is set on respective connecting line；

It is connected with vacuum pump by the 3rd pipeline at the bottom of described first adsorption tower tower, and control valve is set in the 3rd pipeline V3—A；Described vacuum pump is connected with heavy constituent surge tank；By respective connecting line and the 3rd at the bottom of the tower of remaining seven adsorption tower Pipeline is connected, and arranges control valve (V3 B to V3 H) on respective connecting line；

It is connected by the second pipeline and the second compressor at the bottom of described first adsorption tower tower, and control is set in the second pipeline Valve V2 A；Described second compressor is connected with intermediate species surge tank；By respective connecting line at the bottom of remaining seven adsorption tower tower It is connected with the second pipeline, and control valve (V2 B to V2 H) is set on respective connecting line；

It is connected by respective connecting line and the first pipeline at the bottom of described eight adsorption tower towers, and sets on respective connecting line Putting control valve (V1 A to V1 H), described first pipeline is connected with unstripped gas air inlet.

When carrying out pressure-variable adsorption, use multiple adsorption towers arranged side by side, utilize each component in unstripped gas in adsorbent The difference of adsorbance, obtains multiple product gas under different time and step, and each circulation of its technological process includes absorption, puts Change one, blood pressure lowering, along putting, replace two, evacuate, all press liter, final rise pressure:

(1) unstripped gas is the mixed gas of three components, and between component, adsorption capacity has notable difference in predetermined adsorbent To reach the purpose separated.

(2) enter from the bottom of tower after the gas that gas is enrichment intermediate species of displacement one employing is pressurized, the pressure of displacement Identical with adsorptive pressure.

(3) displacement two employing is through entering at the bottom of tower from the easiest absorbed component of extraction at the bottom of tower, and displacement pressure uses normal pressure A certain pressure between adsorptive pressure is carried out.

The detailed process of above-mentioned pressure-swing absorption process is: through pipeline from entering in adsorption tower at the bottom of tower after unstripped gas pressurization, will Component by adsorbance be designated as from small to large difficulty, in, easily, in tower, now also can form absorbed component crest in the middle of three mass-transfer zones Charging is stopped when arriving a certain position but do not penetrate；By another tower along letting slip the richness of extraction in journey and second time replacement process Carry out replacing for the first time from being passed through at the bottom of tower after the gas pressurized of collection intermediate species, displacement the most difficult discarded absorbed component extraction, when Displacement for the first time is stopped when intermediate species will penetrate；This adsorption tower is connected with other adsorption towers and carries out n times and all press that (N is more than Equal to 2 less than adsorption tower number), in the tower being, pressure reduces, and reclaims the difficult absorbed component in dead space, and improves intermediate species Concentration；Carry out second time to replace, use the easy absorbed component of extraction at the bottom of vacuumizing phase tower to do unstripped gas and be passed through from the bottom of tower, with Time obtain replacing tail gas for rich in intermediate species product gas at tower top, stop charging when easy absorbed component will penetrate；When Add forward depressurization step when twice replaced pressure is higher than normal pressure, obtain intermediate species product gas, the most easily absorption group from tower top Divide and completely penetrated through；Vacuum step is from obtaining highly purified easy absorbed component at the bottom of tower and making adsorbent bed be regenerated；Taking out After vacuum terminates, with the gas from other High Pressure Absorption towers, it is carried out the equal boost process of n times, this process and drop pressure mistake Journey is corresponding；After all pressure terminates, in order in reaching tower, pressure changes stable purpose, the difficult absorption of partial high pressure power is used to produce Product gas is back in tower by final rise pressure pipe road, makes pressure in tower reach adsorptive pressure ready for circulation next time.Multiple suctions Attached tower is set up side by side, and alternating sequence carries out above absorption regeneration cyclic process, just can realize the separation for ternary component The purpose purified.

In the inventive solutions, pressure-swing absorption process is selected have 2 24 adsorption towers and install side by side.

In the inventive solutions, unstripped gas fill process uses low pressure feed, and feed entrance point is gas phase group in tower Become place consistent with unstripped gas.

In the inventive solutions, multi-reflow step includes that evacuation at the bottom of tower is back to after obtaining heavy constituent pressurization Another tower carries out absorption displacement, and displacement obtains being rinsed regeneration and boosting in light component Parts is back to lower pressure column.

In the inventive solutions, multi-reflow step includes the first time displacement using part intermediate products, adopts Replace by the second time of absorbed component product easy at the bottom of tower, use part difficult absorbed component backflow to carry out middle final rise pressure.

In the inventive solutions, displacement for the first time refluxes after using the pressurization of intermediate species product gas, is replaced Tail gas difficult absorbed component product gas consistent with absorption tail gas, and cancel displacement tail gas recycle step.

In the inventive solutions, all press gas that intermediate species exceeds standard by the stage along airintake direction gradually to Other adsorption towers carrying out boost pressure or all pressure towers carry out 2 24 drop pressures, the most corresponding adsorption tower or all press Tower carries out 2 24 boost pressures.

In the inventive solutions, second time displacement uses evacuation to return after obtaining the pressurization of easy absorbed component product gas Flowing in tower, displacement tail gas is as enrichment intermediate species product gas extraction.

The mode of traditional pressure-variable adsorption employing high pressure charging, maximum pressure during i.e. adsorptive pressure is cyclic process, and this Patent can which decrease energy consumption, can use two towers or four for the separation of binary composition in the way of using low pressure feed Tower and the operation of multitower.The separation of three components obtains the highly purified product of at least two and one by the way of twice is all pressed Enriched products.Rectification process is combined by present invention process flow process with pressure swing adsorption technique.Use pressure or natural back flow many In the technique of secondary backflow makes tower, component can cross clear segmentation, obtains highly purified two or three material by set of device, Thus reach the energy-saving and cost-reducing purpose reducing investment.

Accompanying drawing explanation

Fig. 1 is to utilize technical solution of the present invention to carry out binary composition two-tower process schematic diagram.

Fig. 2 is to utilize technical solution of the present invention to carry out binary composition four-column process flow schematic diagram.

Fig. 3 is to utilize technical solution of the present invention to carry out ternary component eight tower schematic flow sheet.

Detailed description of the invention

Technical scheme is further illustrated below in conjunction with specific embodiment.

Tradition two tower pressure swing adsorption techniques can only obtain the product that a kind of purity is higher, the most common making oxygen by air separation technique Its raw material such as following table, typically can only obtain oxygen rich air, and rich nitrogen can only be vented owing to purity does not reaches.

Composition	O₂	N₂	Ar	CO₂	Other	Add up to
							Concentration (vol%)	20.93	78.03	0.932	0.03	0.078	100

Temperature :≤45 DEG C

Embodiment 1:

And utilizing the present invention while can obtaining same purity oxygen rich gas, to obtain highly purified rich nitrogen, its purity reaches To 98.5Vol%.Determining that weight component, light component are oxygen absorbing complexity, restructuring is divided into nitrogen, in adsorption tower by Under on equipped with molecular sieve, feed pressure is 101-130KPa, heavy constituent N₂Displacement pressure is 130-300KPa, evacuated pressure For 50-70KPa(absolute pressure).The flow chart of two tower pressure-variable adsorption separation air is as shown in Figure 1:

Circulation step such as following table.

time/s

40

10

40

10

A tower

F/LR

ER

HPP

HR/RP

ED

VU

B tower

HR/RP

ED

VU

F/LR

ER

HPP

Specifically, with A tower and B tower each step of alternate run within a cycle, reach constituting complete cycle The purpose run continuously, realizes twice backflow in a circulation.

(1) unstripped gas air inlet and difficult absorbed component backflow (F/LR)

First control valve, the 3rd control valve, the 4th control valve, the 6th control valve and the 9th control valve are opened, remaining valve Close.First adsorption tower (A tower) is in low-pressure state, and unstripped gas is consistent with feeding gas composition via V-1 gas phase composition in tower Position feeds, and adsorbent optionally adsorbs easy absorbed component N₂；First adsorption tower Tower bottom gas controls through the 6th simultaneously Valve, vacuum pump, surge tank, compressor, the 9th control valve, the second adsorption tower (B tower), the 4th control valve, the 3rd control valve backflow To the first adsorption tower, part O of backflow₂, purge in tower and boost；Open V-6 at the bottom of tower to carry out evacuation and obtain N₂.Work as pressure Power stops after being raised to feed pressure 101KPa-130KPa.

(2) boost pressure (ER)

5th control valve is opened, and remaining is closed；Due in the first step, for being two to enter one for the first adsorption tower Go out, cause air pressure inside to rise, cause charging not smooth, therefore charging is opened valve V-5 after terminating and it is connected with the second adsorption tower Carry out boost pressure process so that its pressure continues to raise, and the mode all pressed such as figure uses overhead mode, it is also possible to choosing Select at the bottom of tower at the bottom of tower or mode at the bottom of tower top tower.

(3) easily absorbed component boosts (HPP)

Opening the 7th and the 8th control valve, remaining is closed；In order to make integral pressure change steadily, after needing boost pressure A tower boost further, use mode in V-8 is back to tower after the easy absorbed component pressurization that evacuation obtains, make pressure Reach to replace pressure 130-300KPa.

(4) easily (HR/RP) is replaced in absorbed component backflow

Open second, third, the four, the 7th and the 8th control valve, remaining control valve is closed；Unstripped gas via V-2 at tower Interior gas phase composition forms the charging of consistent position with feeding gas, and adsorbent optionally adsorbs easy absorbed component N₂；Simultaneously second Adsorption tower (B tower) Tower bottom gas through the 7th control valve, vacuum pump, surge tank, compressor, the 8th control valve to the first adsorption tower (A tower), will displace difficulty absorbed component, from tower after part easily absorbed component pressurization in V-8 is back to the first adsorption tower Top obtains through V-3, stops charging when easy absorbed component will penetrate.

(5) drop pressure (ED)

Opening the 5th control valve, remaining control valve is closed；Owing in tower, pressure is higher, the most easily absorbed component is the most complete Penetrate, there is a certain amount of difficult absorbed component in dead space, the first adsorption tower (A tower) is connected warp with the second adsorption tower (B tower) 5th adsorption tower V-5 all presses, the gas in recovery section mechanical energy and space.

(6) evacuation (VU)

6th and the 9th control valve is opened, and remaining control valve is closed；All after pressure drop, in tower, pressure reduces, and opens V-6 and carries out Vacuum step using in tower highly purified easy absorbed component solution suck vacuum buffer tank and be partly refluxed to another tower section as Product extraction.

Shown in the whole circulation following form of inner valve switch conditions, O-opens；X-closes

Time/s

40

10

40

10

Step

1

2

3

4

5

6

V-1

O

X

V-2

X

O

X

V-3

O

X

O

X

V-4

O

X

O

X

V-5

X

O

X

O

X

V-6

O

X

O

V-7

X

O

X

V-8

X

O

X

V-9

O

X

O

In implementation process, if if two adsorption towers (A tower and B tower) in height cannot meet, select first Adsorption tower A tower is split as both two adsorption towers A1, A2(series connection), the second adsorption tower B tower is split as two adsorption towers B1, B2 (both series connection), unstripped gas by pipeline with at the bottom of adsorption tower A1 tower, adsorption tower A2 tower top be connected, and the first control valve be set, former Material gas by pipeline with at the bottom of adsorption tower B1 tower, adsorption tower B2 tower top is connected, and arranges the second control valve, as shown in Figure 2.At tool In body implementation process, use the circulation step identical with embodiment, adsorption tower A1, A2 and adsorption tower B1, B2 are respectively seen as One adsorption tower A and the second adsorption tower B, can obtain heavy constituent at the bottom of tower, tower top obtains light component.

Embodiment 2:

The unstripped gas of this example is the low concentration coal-bed gas containing carbon dioxide or oilfield fireflood tail gas, after the pretreatment of front end It is purified and removes wherein C²The impurity such as above hydro carbons and sulfur-containing compound.Obtain composition such as the gas of following table:

Composition	N₂	CH₄	CO₂	Add up to
					Concentration (vol%)	85	9	6	100

Temperature :≤45 DEG C

The present invention uses one-stage process that ternary component adsorbing separation obtains at least two height pure component and a kind of ambuscade component, Device flow chart as shown in Figure 3, adsorption tower A-H totally eight composition pressure-swing absorption apparatus.Active oxidation is loaded in adsorption tower Aluminum and activated carbon, tower top obtains two kinds of products in different phase, obtains a kind of product at the bottom of tower, during adsorption step pressure be 200KPa-2000KPa(absolute pressure).Obtaining nitrogen gas purity after flow process of the present invention is 99.4%, and methane gas purity is 77.1%, two Carbonoxide purity is 99.3%.Eight composition pressure-swing absorption apparatus as shown in Figure 3, described eight adsorption tower parallel connections:

A kind of circulation time-scale of adsorbent equipment is as follows:

(1) adsorption step (AD)

Being entered in adsorption tower by valve V1-A after unstripped gas is pressurized, adsorption tower internal adsorption agent is adsorbed the most successively Carbon dioxide, methane and nitrogen component, the part nitrogen of difficult absorption flows out from outlet V5-A, and a part is made as a product part Boost in V5-B enters and is in the B tower of whole pressurising step for backflow gas, when adsorbent unstripped gas is the most saturated, Stop air inlet adsorption step to terminate.

(2) displacement step (RP1) for the first time

The gas pressurized of enrichment intermediate species methane is passed through in adsorption tower through V2-A backflow after identical with adsorptive pressure, Nitrogen is replaced by the effect strong compared with nitrogen by the adsorbed ability utilizing intermediate species methane, and displacement tail gas is equally from tower Top V5-A extraction.Stop when methane will penetrate being passed through displacement gas, for the first time a replacement completion.

(3) drop pressure (ED)

For the first time after replacement completion, in adsorption tower, in dead space and headroom, nitrogen gas concn is higher, this part nitrogen and Pressure needs to recycle, to this end, the gas in adsorption tower is discharged warp from upper buck, gas from adsorption tower top V6-A V6-E/F enters this section and is complete in the corresponding adsorption tower of regeneration, and ED number of drop pressure can be thought 1 time or repeatedly (2-7 Secondary).(4) displacement step (RP2) for the second time

After all pressure step ED terminates, now in adsorption tower, nitrogen major part is replaced, is adsorbed with substantial amounts of methane gas and portion Divide carbon dioxide.By after the gas pressurized of carbon dioxide-enriched in V4-A is passed through tower higher compared with methane according to its adsorbed ability Principle methane in adsorption tower is replaced, displacement tail gas be enrichment methane product gas enter surge tank through V7-A.When two Second time displacement step is stopped when carbonoxide will penetrate.

(5) step (CoD) is forward bled off pressure

After second time displacement, in tower, methane content reduces, but also remaining has a large amount of methane in tower top and dead space, It is thus desirable to reclaim this portion of methane to simultaneously work as improving the purpose of carbon dioxide purity, now it is similarly high methane gas along venting Collect from tower top V7-A and obtain.After pressure reduces to normal pressure, now in tower, carbon dioxide completely penetrates through, and stops the step of forward blood pressure lowering Suddenly.

(6) vacuum step (VU)

Forward bleed off pressure rear tower internal adsorption for carbon dioxide, by vacuum pump by adsorbent carbon dioxide through V3-A Extract out side by side as in vacuum buffer tank a part make the backflow displacement after pressurization of a product part, suction in the adsorption tower being simultaneously Attached dose is regenerated.

(7) boost pressure step (ER)

When adsorption tower completes regeneration, utilize forward blood pressure lowering ED step expellant gas, enter adsorption tower from the port of export and make it Pressure raises, this step and forward depressurization step one_to_one corresponding.

(8) whole boosting step (FR)

Utilize the high pressure nitrogen that adsorption step tower top flows out, carry out the adsorption tower after refluxing for boost pressure and carry out finally Boosting so that pressure reaches adsorptive pressure.

Concrete circulation inner valve switch conditions form is as follows, and O-opens；X-closes

Time/s

60

Step

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

V1-A

O

X

V1-B

X

O

X

V1-C

X

O

X

V1-D

X

O

X

V1-E

X

O

X

V1-F

X

O

X

V1-G

X

O

V1-H

O

X

O

V2-A

X

O

X

V2-B

X

O

X

V2-C

X

O

X

V2-D

X

O

X

V2-E

X

O

X

V2-F

X

O

V2-G

O

X

V2-H

X

O

X

V3-A

X

O

X

V3-B

X

O

X

V3-C

O

X

O

V3-D

X

O

X

V3-E

X

O

X

V3-F

X

O

X

V3-G

X

O

X

V3-H

X

O

X

V4-A

X

O

X

V4-B

X

O

X

V4-C

X

O

X

V4-D

X

O

V4-E

O

X

V4-F

X

O

X

V4-G

X

O

X

V4-H

X

O

X

V5-A

O

X

O

V5-B

X

O

X

V5-C

X

O

X

V5-D

X

O

X

V5-E

X

O

X

V5-F

X

O

V5-G

O

X

O

V5-H

O

X

O

V6-A

X

O

X

O

X

V6-B

O

X

O

X

O

V6-C

X

O

X

O

X

V6-D

X

O

X

O

X

V6-E

X

O

X

O

V6-F

O

X

O

X

V6-G

X

O

X

O

X

V6-H

X

O

X

O

X

V7-A

X

O

X

V7-B

X

O

X

V7-C

X

O

X

V7-D

O

X

O

V7-E

O

X

V7-F

X

O

X

V7-G

X

O

X

V7-H

X

O

X

Above the present invention is done exemplary description, it should explanation, in the situation of the core without departing from the present invention Under, any simple deformation, amendment or other those skilled in the art can not spend the equivalent of creative work equal Fall into protection scope of the present invention.

Claims

1. the pressure swing absorption process of backflow more than a kind, it is characterised in that use adsorption tower parallel way to be connected, and at pipeline In surge tank, vacuum pump and compressor are set, by pending unstrpped gas between adsorption tower in parallel by surge tank, vacuum Pump and compressor realize gas at the bottom of the tower top or tower of adsorption tower in parallel between multi-reflow, to realize group in unstrpped gas The separation divided, obtains with the tower top at adsorption tower and obtains heavy constituent at the bottom of the tower of light component, adsorption tower, divide for binary composition From, use two component four tower patterns: the first adsorption tower and the second adsorption tower are in parallel, select to be split as the first adsorption tower two strings Adsorption tower A1, A2 of connection, is split as adsorption tower B1, B2 of two series connection by the second adsorption tower, and unstripped gas passes through pipeline and absorption At the bottom of tower A1 tower, adsorption tower A2 tower top be connected, and the first control valve is set, unstripped gas by the bottom of pipeline and adsorption tower B1 tower, absorption Tower B2 tower top is connected, and arranges the second control valve；

Tower top at described adsorption tower A1 is connected with the tower top of adsorption tower B1 by pipeline, arranges the 5th on both connecting lines Control valve；Tower top at described adsorption tower A1 receives device by pipeline with light component and is connected, and arranges the 3rd control on pipeline Valve processed；Tower top at described adsorption tower B1 receives device by pipeline with light component and is connected, and arranges the 4th control on pipeline Valve；

It is being connected with vacuum pump by pipeline at the bottom of the tower of described adsorption tower A2, and the 6th control valve is being set on pipeline, also by Pipeline is connected with compressor, and arranges the 8th control valve on pipeline；Pipeline and vacuum is being passed through at the bottom of the tower of described adsorption tower B2 Pump is connected, and arranges the 7th control valve on pipeline, is connected with compressor also by pipeline, and arranges the 9th control on pipeline Valve；Described vacuum pump is connected with surge tank by pipeline respectively with compressor；

For the separation of binary composition, carry out including that evacuation at the bottom of tower is back to after obtaining heavy constituent pressurization with multi-reflow step Another tower carries out absorption displacement, and displacement obtains being rinsed regeneration and boosting in light component Parts is back to lower pressure column, with first Adsorption tower and the second adsorption tower each step of alternate run within a cycle, to constitute what complete cycle reached to run continuously Purpose, realizes twice backflow in a circulation, and in the cycle, step is as follows:

(1) unstripped gas air inlet and difficult absorbed component backflow (F/LR)

First control valve, the 3rd control valve, the 4th control valve, the 6th control valve and the 9th control valve are opened, remaining valve closing； First adsorption tower is in low-pressure state, and unstripped gas feeds via the first control valve, and adsorbent optionally adsorbs easy absorbed component； First adsorption tower Tower bottom gas is through the 6th control valve, vacuum pump, surge tank, compressor, the 9th control valve, the second absorption simultaneously Tower, the 4th control valve, the 3rd control valve are back in the first adsorption tower, purge and boost in tower；The 6th control is opened at the bottom of tower Valve processed evacuates, and stops after pressure is raised to feed pressure；

(2) boost pressure (ER)

5th control valve is opened, and remaining is closed；Charging is opened the 5th control valve after terminating and it is connected with the second adsorption tower and carries out Boost pressure process so that its pressure continues to raise；

(3) easily absorbed component boosts (HPP)

Opening the 7th and the 8th control valve, remaining is closed；In order to make integral pressure change steadily, need the after boost pressure One adsorption tower boosts further, the side that the easy absorbed component using evacuation to obtain is back in tower through the 8th control valve after pressurizeing Formula, makes pressure reach to replace pressure；

(4) easily (HR/RP) is replaced in absorbed component backflow

Open second, third, the four, the 7th and the 8th control valve, remaining control valve is closed；Unstripped gas enters via the second control valve Material, adsorbent optionally adsorbs easy absorbed component；Simultaneously the second adsorption tower Tower bottom gas through the 7th control valve, vacuum pump, Surge tank, compressor, the 8th control valve, to the first adsorption tower, will reflux through the 8th control valve after part easily absorbed component pressurization To the first adsorption tower, difficulty absorbed component is displaced, obtain through the 3rd control valve from tower top, when easy absorbed component will penetrate Time stop charging；

(5) drop pressure (ED)

Opening the 5th control valve, remaining control valve is closed；Connect to enter through the 5th control valve by the first adsorption tower and the second adsorption tower Row is all pressed, the gas in recovery section mechanical energy and space；

(6) evacuation (VU)

6th and the 9th control valve is opened, and remaining control valve is closed；Open the 6th control valve and carry out vacuum step by Ta Neigao The easy absorbed component solution of purity sucks vacuum buffer tank and is partly refluxed to another tower section as product extraction.

The pressure swing absorption process of a kind of many backflows the most according to claim 1, it is characterised in that built-in at described adsorption tower Enter the one in activated alumina, Kiselgel A, activated carbon or molecular sieve.