CN1070840A

CN1070840A - The technology of pressure-changed adsorption concentrating hydrogen

Info

Publication number: CN1070840A
Application number: CN 92110918
Authority: CN
Inventors: 曹寿康; 梁福忠; 刘中捷; 王文彬
Original assignee: Sinopec Luoyang Petrochemical Engineering Corp; China Petrochemical Corp
Current assignee: China Petrochemical Corp; Sinopec Luoyang Guangzhou Engineering Co Ltd
Priority date: 1992-09-24
Filing date: 1992-09-24
Publication date: 1993-04-14
Anticipated expiration: 2007-09-24
Also published as: CN1025110C

Abstract

The invention provides a kind of ten tower process that are applicable to from hydrogeneous unstripped gas with pressure-changed adsorption concentrating hydrogen, i.e. L10-4-4 technology.It by absorption, regenerate and the step of boosting constitutes, be characterized in that four towers are in adsorption step simultaneously, adopted and all pressed for four times, rise and the pressurising of product hydrogen for four times.Improved the processing power of device, made product hydrogen increase the yield of 1～2% (body).

Description

The technology of pressure-changed adsorption concentrating hydrogen

The invention belongs to the gas delivery field, relate in particular to transformation absorption (PSA) process of separating hydrogen gas from hydrogen-containing gas.Its international Patent classificating number is B01D53/04.

As everyone knows, in many oil refining and chemical plant installations dispensing gas, all contain hydrogen, for example: devices such as hydrofining, hydrocracking, catalytic cracking, synthetic ammonia, hydrocarbon cracking system alkene, synthesizing methanol, catalytic reforming.That is discharged out contains hydrogen mixed gas, also contains N usually ₂, CO, CO ₂, H ₂O, Ar and C ₁-C ₄Hydrocarbon etc.

About the separation of gas, as far back as U.S.P3 in 1969,430,418 disclosed the PSA technology of once all pressing; U.S.P.3 in 1971,564,816 disclose the PSA technology that four tower secondaries are all pressed, and this technology is widely used in separates hydrogeneous gas mixture, and its hydrogen purity reaches 99.999%.Be expansion instrument throughput, improve hydrogen recovery rate, U.S.P.3,986,849[1] multitower PSA technology disclosed.[1] be 10 adsorption tower technical process, all pressures are arranged in a loop cycle three times, each constantly always has three adsorption towers to be in adsorption step, and other seven towers are in the different regeneration stages respectively.This technology is called for short 10-3-3 flow process (referring to accompanying drawing 1), and the working routine of adsorption tower is seen accompanying drawing 2.Found out that by figure this technology is promptly carried out all pressing for three times, forward put pressures, reversely puts pressure, washes after certain tower adsorption step finishes, a loop cycle is finished in three pressurisings, the pressurising of product hydrogen.USP4402712[2] new 10 tower PSA technologies (seeing accompanying drawing 3,4) are disclosed.It is three all pressure, the absorption of four towers, abbreviates the 10-3-4 technical process as.Its goal of the invention is to solve the method that can handle two kinds of unstripped gass simultaneously.After certain tower adsorption step finishes, begin to carry out all to press for three times, forward put pressure, reversely then put pressures, wash.Regeneration step finishes.Then, enter the step of boosting, i.e. three pressurisings, the pressurising of product hydrogen has entered adsorption step again.Document [2] is compared with [1], and its difference is that [2] can adopt two kinds of unstripped gass, and two feeding lines are arranged, two waste lines, and four towers are in adsorbed state simultaneously.When processing power was identical, [2] wanted littler than the adsorption tower size of [1].The weak point of document [2] is: when the hydrogen richness of two kinds of unstripped gass differs bigger, if by hydrogeneous high unstripped gas design adsorption time, the absorb leading-edge of then handling in the low adsorption tower of hydrogen richness will penetrate, and can not guarantee the purity of product hydrogen; If by low hydrogeneous unstripped gas design adsorption time, the sorbent material of then handling in the high hydrogenous adsorption tower can not make full use of, and will reduce the yield of product hydrogen.Moreover, when one of unstripped gas flow changes, then can not adjust adsorption cycle automatically, thereby make it can not be in optimal operational condition with fluctuations in discharge.

The present invention proposes a kind of improved being used for from containing ten tower pressure swing adsorption techniques of hydrogen mixed gas separating and concentrating hydrogen.The yield of the hydrogen product of this technology is than prior art height, and under the same treatment ability, its sorbent material lacks than the consumption of 10-3-3 flow process, and the adsorption tower size is littler than 10-3-3.

Ten tower flow processs of the present invention are four all pressures, and four towers adsorb simultaneously, abbreviate the L10-4-4 technical process as.This technology at any time in, always have four towers to be in adsorption step, other six towers then are in the different regeneration and the step of boosting respectively.This technology by absorption, regenerate and three steps of boosting constitute a loop cycle.Separated unstripped gas enters adsorption tower through feed line, and through adsorbents adsorb, product hydrogen is delivered to the hydrogen basin by the product pipeline.After adsorption step is finished, enter regeneration step.Regeneration step comprises all presses, forward puts pressure four times, reversely puts pressures, washes.After regeneration step finishes, enter (also claiming pressurising, the down together) step of boosting.The step of boosting comprises: four pressurisings and the pressurising of product hydrogen.So just finished a loop cycle.L10-4-4 technology of the present invention always has four towers to be in adsorption step in arbitrary moment of operation, and all the other each towers are in the regeneration and the step of boosting respectively.

Adopt the present invention can bring into play the effect of sorbent material to greatest extent, can improve hydrogen yield 1-2%(body).

Accompanying drawing 1-8 and nomenclature thereof:

Accompanying drawing 1 is the PSA10-3-3 schema;

Accompanying drawing 2 is each tower working routine of PSA10-3-3 flow process;

Accompanying drawing 3 is PSA10-3-4 schemas;

Accompanying drawing 4 is each tower working routine of PSA10-3-4 flow process;

Accompanying drawing 5 is PSAL10-4-4 schemas;

Accompanying drawing 6 is each tower working routine of PSAL10-4-4 flow process;

Accompanying drawing 7 is each tower working routine of PSA L8-2-3 flow process;

Accompanying drawing 8 is each tower working routine of PSA L5-2-2 flow process.

Symbol in the accompanying drawing:

A-absorption, E1D-once all presses,

The E2D-secondary is all pressed, and E3D-all presses for three times,

E4D-all presses for four times, and PP-is forward put pressure,

The reverse pressure of putting of D-, the P-flushing,

A pressurising of E1R-(promptly boosting, down together), the pressurising of E2R-secondary,

Three pressurisings of E3R-, four pressurisings of E4R-,

The pressurising of R-product gas, the Ff-unstripped gas,

Wg-waste gas, P _H-product hydrogen;

The numbering of adsorption tower is respectively with Arabic

numerals

1,2,3,4,5,6,7,8,9,10 expressions; Dated digital valve among the figure (

) be stopping valve.

PSA L10-4-4 technology of the present invention is that 10 adsorption towers are divided into odd number (being

tower

1,3,5,7,9) series and two series of even number (being

tower

2,4,6,8,10) series, their shared feed line, an exhaust pipe and a product pipeline respectively.

Below by accompanying drawing 5-8 PSAL10-4-4 technology of the present invention is carried out concrete description.

Now take tower 1 as example. Unstripped gas enters adsorption tower 1 by valve 11, and product hydrogen is delivered to product storage tank by valve 12 by shared product line, and impurity is adsorbed by the adsorbent in the tower. The absorption step of tower 1 enters the regeneration step after finishing, and the adsorbent of tower 1 is regenerated. Tower 1 is once all pressed (E1D) by

valve

16,66 pairs of towers 6, (this moment tower 6 be the 4th time boost), by

valve

16,76 pairs of towers 7 carry out secondary and all press (E2D) (tower 7 is to boost for the third time), undertaken three times and all press (E3D) by

valve

13,83 pairs of towers 8, (tower 8 be boost for the second time) all presses (E4D) to be by

valve

13,93, tower 9 is once boosted the 4th time. All press the hydrogen that to store in the tower 1 to be recovered in

tower

6,7,8,9 four towers by above-mentioned four times, improved simultaneously their pressure, impurity on tower 1 adsorbent obtains the part desorb, tower 1 after all pressing for four times forward bleeds off pressure (PP) by valve 15,105,104, to tower 10 flushings, the impurity on desorber 10 adsorbents. Afterwards, tower 1 carries out reverse bleeding off pressure (D) by valve 14, makes the further desorb of impurity on tower 1 adsorbent, and the exhaust pipe discharger by sharing. Then, forward bleed off pressure gas with tower 2 and wash (P) by

valve

25,15,14 pairs of towers 1. Tower 1 regeneration step finishes. The gas of then, all pressing for the 4th time with tower 3 carries out pressurising (E one time by

valve

33,13 pairs of towers 1₁R); The body of all calming the anger for the third time with tower 4 passes through valve 43,13 couples of tower 1 for the second time pressurising (E₂R); Pass through with the body of all calming the anger the second time of tower 5 Valve 56, the 16 pairs of towers 1 be pressurising (E for the third time₁R); All calm the anger for the first time body by valve 66, the 4th pressurising of 16 pairs of towers 1 with tower 6, use at last product hydrogen that adsorptive pressure is arrived in tower 1 pressurising (R). Finished a cycle period of absorption divided gas flow.

When tower 1 had been finished absorption (A) step, tower 5 had entered the absorption step. Enter the tower 1 of regeneration step when having finished the second time when all pressing, tower 2 has been finished the absorption step, and tower 6 has entered the absorption step. This shows two adjacent adsorption towers (

tower

1,2,3 for example ...) between differed for two steps (seeing accompanying drawing 6), whenever carrying out two step regeneration then has a tower to finish the absorption step, has simultaneously another adsorption tower to finish to boost step and enters the absorption step.

PSA L10-4-4 technology of the present invention, in operational process, parts under certain tower break down, when causing this tower not run well, then can (automatically or manually) switch to the operation of eight towers by the operation of ten towers, promptly become secondary and all press, eight tower flow processs of three towers absorption abbreviate PSA L8-2-3 flow process as.

Switch the operation of 8 towers by the operation of 10 towers, respectively cut away a tower in Ying Congqi, two series of idol, and should from a series, not cut away two adsorption towers.10 towers become 8 towers, and five kinds of handover schemes can be arranged, and each tower working routine of these five kinds of schemes is seen accompanying drawing 7.Suppose that now tower 9 breaks down, then cut away tower 9, tower 10, become

tower

1,2,3,4,5,6,7,8 and be in running status.Be that example illustrates the L8-2-3 technical process now with tower 1.That is:

Unstripped gas enters tower 1 by valve 11, and product hydrogen is delivered to the hydrogen basin by valve 12 by shared pipeline, and impurity is attracted on tower 1 sorbent material.Tower 1 adsorption step is once all pressed (E by 16,56 pairs of towers 5 of valve after finishing ₁D), tower 5 is secondary booster (E ₂R), tower 1 once all presses the back forward to put pressure (PP) by

valve

15,75, and tower 7 is washed (P), makes the impurity desorb on tower 7 sorbent materials.Afterwards, carry out secondary by

valve

15,75 and all press (E ₂D), to the tower 7 (E that once boosts ₁R).Secondary carries out the reverse pressure (D) of putting by valve 14 after all pressing, and makes impurity desorb further on the sorbent material in the tower 1, and by shared waste line discharger.Then, pressure (PP) gas of forward putting by

valve

35,15 usefulness towers 3 washes (P) to the reverse tower of putting after the pressure 1, makes the impurity on its sorbent material obtain desorb, then all presses (E with the secondary of tower 3 ₂D) gas advances once (the E that boosts by 35,15 pairs of towers 1 of valve ₁R), once all press (E with tower 5 ₁D) gas carries out secondary booster (E by 56,16 pairs of towers 1 of valve ₂R).Afterwards, arrive adsorptive pressure with product hydrogen by 12 pairs of tower 1 pressurisings of valve.Finish a fractionation by adsorption loop cycle.

When being switched to 8 towers (L8-2-3) flow process by 10 towers, its processing power remains unchanged substantially, and just yield slightly reduces, and the 10-3-3 of document [1] is when switching to 8-2-2, and its processing power descends about 20%, and yield slightly descends.

L10-4-4 flow process of the present invention is in operation, if the synergic system parts in odd number series or the even number series, perhaps break down simultaneously with two or more adsorption towers in a series of, then can (automatic or manual) switching fall out of order adsorption tower series, make trouble free series continue operation.At this moment operational scheme is the L5-2-2 flow process, and promptly secondary is all pressed (E ₁D, E ₂D), two towers adsorb simultaneously.The working routine of this each tower of flow process is shown in accompanying drawing 8.Here suppose that even number series is cut off, become

tower

1,3,5,7,9 these five tower operations.Be that example illustrates the L5-2-2 flow process still now with tower 1.As follows:

Unstripped gas enters adsorption tower 1 by valve 11, and product hydrogen is delivered to the hydrogen basin by valve 12 by shared pipeline, and impurity is attracted on the sorbent material in the tower 1.After tower 1 adsorption step (A) finished, tower 1 was once all pressed (E by 16,76 pairs of towers 7 of valve ₁D), (this moment, tower 7 was to boost for the second time).After once all pressing, tower 1 is forward put pressure (PP) by

valve

15,95, and tower 9 is washed (P), makes the impurity desorb on tower 9 sorbent materials.Then, tower 1 carries out secondary and all presses (E ₁D) gas once boosts by 15,95 pairs of towers 9 of valve.Tower 1 after secondary is all pressed carries out the reverse pressure (D) of putting through valve 14, makes the impurity desorb further on tower 1 sorbent material, and by shared waste line discharger.The gas of forward putting pressure (PP) with tower 3 washes (P) to tower 1 then, with the impurity on its sorbent material of desorb.Afterwards, all press (E with tower 3 secondaries ₂D) gas carries out pressurising (E one time by 35,15 pairs of towers 1 of valve ₁R), once all press (E with tower 5 ₁D) gas carries out secondary pressurising (E by 56,16 pairs of towers 1 of valve ₂R), use product hydrogen to arrive adsorptive pressure then through 12 pairs of tower 1 pressurisings of valve (R).Finish a fractionation by adsorption loop cycle.

The 10-3-3 flow process ratio of the same document of L10-4-4 flow process [1], when all switching to the operation of five towers, L5-2-2 flow process of the present invention is bigger than the treatment capacity of the 5-2-1 flow process of document [1].

Embodiment

Example 1, unstripped gas composed as follows, its pressure is 2.45MPa.Requiring the purity of product hydrogen is 99.99%

Form	H ₂	CO	CH ₄	CO ₂
					The %(body)	70.91	2.96	6.5	19.56

(V), CO content is not higher than 10ppm, CO ₂Content is not higher than 10ppm.Examination is the long-pending and hydrogen yield of tower body of 10-3-3, L10-4-4 flow process relatively.It the results are shown in table 1:

Be not difficult to find out that from table 1 the present invention exceeds at the hydrogen yield under 1% the situation, the cumulative volume of its 10 towers is littler 35.3 meters than 10-3-3 ³, be equivalent to save sorbent material 25%.This is very favourable to the cost, the saving sorbent material that reduce adsorption tower.

The composition of example 2, unstripped gas and its pressure are with example 1.Purity and foreign matter content to product hydrogen require identical with example 1.Examination relatively switches to the 8-2-2 of 8 towers operation, the difference of L8-2-3 flow process by the operation of 10 towers, the results are shown in Table 2.

Table 2

Process indicator	8 － 2 － 2	L8 － 2 － 3
			Loop cycle, second	779	640
Adsorption time, second	180	240
			Processing power (comparing) with 10 towers	Descend 20%	Substantially do not descend

The result shows that the processing power of L8-2-3 flow process is originally identical with original 10 column foots, can not influence the hydrogen supply amount of downstream unit.

Equally, technical process of the present invention, when switching to the operation of five towers, promptly still the 5-2-1 flow process than document [1] is superior for the L5-2-2 flow process, and its processing power is big more a lot of than the latter.

Claims

1, a kind of ten tower process that are applicable to from hydrogeneous unstripped gas with pressure-changed adsorption concentrating hydrogen, form a loop cycle by adsorption step, regeneration step and the step of boosting, the time there are four towers to be in adsorption step simultaneously in operation, it is characterized in that the L10-4-4 process using all presses (E four times ₁D, E ₂D, E ₃D, E ₄D), forward put pressure (PP), the reverse pressure (D) of putting, flushing (P); Adopt four times the (E that boosts ₁R, E ₂R, E ₃R, E ₄R) and product hydrogen pressurising (R), improve the yield of product hydrogen.

2, L10-4-4 technology according to claim 1, it is characterized in that when a certain adsorption tower of having finished adsorption step enters regeneration step, whenever carry out two step regeneration and enter adsorption step, just have a tower to finish adsorption step with regard to having a tower to finish to boost step.

3, L10-4-4 technology according to claim 1, when this technology can not normally be moved because the parts of a certain adsorption tower break down in operational process, changeable one-tenth eight tower flow processs turn round, it is characterized in that this eight tower process flow process is L8-2-3, promptly always have three towers to be in adsorption step at any one time; Adopt secondary all to press (E ₁D, E ₂D), secondary booster (E ₁R, E ₂R) and the pressurising of product hydrogen to adsorptive pressure.

4, L10-4-4 technology according to claim 1, synergic system parts in odd number series or even number series, when perhaps breaking down with the two or more adsorption towers in a series of, changeablely fall out of order series, becoming five tower flow processs moves, it is characterized in that this five tower process flow process is L5-2-2, promptly always have two towers to be in adsorption step at any one time; Adopt secondary all to press (E ₁D, E ₂D), secondary booster (E ₁R, E ₂R) and product hydrogen pressurising (R) to adsorptive pressure.