DE1814064C - Method and device for selective absorption - Google Patents

Description

2. The method according to claim 1, characterized. üaJ the gas mixture up to the condensation area at least one to be absorbed Component is cooled.

3. The method according to claim 2, characterized in that that the gas mixture is removed from the washing column at a point where the The partial pressure of the component to be condensed is as great as U. da «when transferring the to Remove the necessary amount of cold from the solution tank, condensation already occurs: .nd that the Gas mixture ansc '<l, eHend in to the condensed constituent saturated state again in the washing column recirculated w.rd.

4. The method according to claim 3, characterized in that that the liquid condensed out of the gas mixture is at least partially reintroduced into the washing column.

5. The method according to claim 4, dadurcii gekenn / eichnel. that the condensate, together with the mixture of ciases, falls under its own gradient is reintroduced into the wash column.

6. The method according to any one of claims 1 to 5, characterized in that the gas mixture is cooled by heat exchange with a solution cooled by degWn.

7. Falsehood after one of the AiispriidK- I bis (, thereby gcktnnzcitl.net. That the in " Warmeansiausth with the OasiKimsch" linimle Flfcsifkcüsnitnitnitnitnitnitnitnitnitnitnitnitnitnitnad to the ". Jasen durd, eme _{thus the} solubility so

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Solution evolves

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U a pump (3.)

r ,. ⁽ U ^! Zig "Sh A" _Sp , "ch .0, thereby gektnn / eidmet, UaB from the, Ab _S d, dJcr (.IO) S ₅ rinc I tilling (33) you nasty CO. Product wugiisi

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Process have the disadvantage that the amount of increases while the temperature level at which the extraneous cold remaining in the solution when relaxing has to be transferred. Is the heat constituents very large and the desorption capacity of the gas mixture greater than that of the recoverable gas Amount of cold correspondingly low solvent, as can be the case if the is. This increases the need for external cooling. 5 absorption under higher pressure is carried out Due to the large amount of solvent or if the solubility of the gases to be washed out furthermore, an increased consumption of pump energy is very large and the required solvent quantity and at Dai.ipf for regeneration as well as increased relative is correspondingly low, the external cold can at losses in heat exchange. higher temperature than with the loading

If the pure solvent is used before cooling of the washing liquid is known. In this case, the external source of cold enters the column.
turn level, a further increase in energy is the result. If, on the other hand, the idea of an evaporator is that the gas mixture is built into the column, then the required heating up to the condensation area is at least one which is too flattened, and the refrigerant evaporator is only a sorbent component. The Vorsehwer accessible, and in the event of leaks to be washed, part of this procedure consists in the fact that the Löiks gas enters the refrigerant circuit. In the case of working heat, at least some of the heat is dissipated in the form of accounts with a condensation heat arranged outside the column. This means that the cooling stage is a cold pump for large quantities of the temperature difference, which is necessary for transferring saturated solution and a device for restoring a certain amount of cold, is to be provided for the liquid in the column. d. This means that the cold at a higher temperature and lasts: ul in addition, the heat equivalent must be generated with less energy, pimping work can be compensated by the external cold source.
v. it will be. 25 If the coolant removed from the washing column is

l) ie required- · Cold can finally in known lencle gas mixture in the Bc to be condensed

Alternatively, this also means that the washing liquid is in a supernatant unsaturated state, so one achieves

■; it should be ensured that the amount of solvent behaves - the formation of condensate appropriately by

It is kept moderately low that the scrubbing liquid is absorbed by the gas mixture by heat exchange

but bring the dew point stone temperature several times from different columns, then under condensation

b'klen withdrawn and further cools down via the formation of deposits outside the column and the condensate-free

t'corductc Kühlstufeii is performed. In the event of a gas mixture, finally through heat exchange with

a single arranged outside the column warms itself again so far that it enters the

Cooling stage t> e; the disadvantages already outlined can be returned to the washing column. This verse

thereby multiplied. It sint! Experiencing several cold pumps is advantageous if the condensed

Required, the number of connection points on the column component in liquid form; shall be,

and ιΓ. · The number of individual phones will be increased. because at this point in the process there are others in the

The object of the invention is to find more soluble impurities that contain crude gas

drive to create that the disadvantages of the known ones have already been absorbed by the solvent

Method avoids that it is allowed / the 40 are, the condensate falls in a very pure form a: i.

Energy requirements and the outlay on equipment when using a particularly advantageous embodiment of the

To reduce the dissipation of the heat of solution. Condensation of a cast part working

According to the invention, this object is achieved in that the gas mixture solves that the gas mixture is at least partially removed from the pre-Waschsaule at a point In some cases completely, from a central section 45 the partial pressure of this component is so great that the washing column <nnomnien, cooled down and during the transfer of the substances for the discharge of the solution is fed back into the washing column. heat necessary amount of cold already Kondeiisa-Das The gas to be washed is entered on its way and that the gas mixture then enters once withdrawn from this column by the column and saturated with the condensed constituents the next higher column floor is returned to the washing column via a standstill, Half of the column arranged cooling stage closed again The Temperaltirnivcau, in which the heat of solution guided. is to be paid, but is now the responsibility of

With this method, the valid value for leading the soldering with pure gas cooling. This sungswärme necessary cold to transfer is particularly important where the gas line is connected to the fact that the solvent mixture has a lower heat capacity Ικ-sits than the amount due to the temperature and pressure caused by the solvent, because then also here the minimum possible can become. The consequence of this is that it is possible to operate the external cold at a temperature that cannot be recovered during relaxation than when cooling is used, and that the energy requirement of the scrubbing liquid is reduced,
for the pumps, the control of the war and the training. In addition, the thank you is that the liquid condensed out of the gas apparatus for one or more cold mixtures is at least partially pumped and for which, when removed several times, is reintroduced into the washing column, the column has a correspondingly high number of connections. This embodiment recommends then ask when. Finally, to compensate for the washing stage operated according to the invention, a waste heat equivalent of the pump equipment with less additional sorption section is added upstream, in order to provide better cold at egg (. Soluble component beforehand with the same solution.

As the heat capacity of the gas mixture increases, the solvent must be removed. That way it flows

the gas mixture with the poorly soluble constituent because of the saturated solvent, so that liier only the heat of solution of the better soluble component needs to be removed. In the column section in which the to be absorbed If components are fed back in as condensate, only the heat of the mixture is then used free between solvent and condensate; the resulting warming can be neglected will.

It is particularly advantageous here to absorb the Components in the liquid state together with the gas mixture under its own gradient to be reintroduced into the washing column. Under these circumstances, a Kallpumpc is completely unnecessary. It however, it can also be useful to collect the condensate in a separator and at least partially pumped back into the column. In this case only one is for a small amount of liquid designed potash pump to be provided.

The gas mixture is preferably cooled by heat exchange with a solution cooled by degassing. The irreversible cold losses are expediently covered by the fact that a tin heat exchange The amount of liquids determined by the gas mixture before degassing by an external one Cold source is cooled.

The device for performing the method uciiiäü of the invention is characterized by a iiif the middle height of the column from the gas flow above - • inern Säulenbodencn outgoing line, which over a Külilstufc led and is connected to the column again over the next higher [iodine. The cooling level is preferably attached at such a height that condensate is below its own slope get back into the pillar. However, it can also be advantageous to connect a separator downstream of the cooling stage and this not only via the gas line but also via a liquid line with a pump with the Pillar to connect; it is then expedient to have a line for liquid COy from this separator Branch off product.

The raw gas to be processed has the following composition:

R, 61 ° o

N ', CO, Ar, CH ₄ 4 ". Η H., S CO ₂ 34.5 ° · β

0.5 «Vn

It is fed to the system through line 1 at a pressure of about 76 atm. Water-containing condensate collects in separator 2. Methanol is injected into the gas mixture through line 3 in order to prevent the formation of ice in the parts of the apparatus which are below the sound. The raw gas now passes into the heat exchanger 4, in which it is cooled against cold Zcricgungsproduktc, namely against the hydrogen-nitrogen mixture arriving through line 5 α from the nachgcschallcten, not shown liquid nitrogen scrubbing and against a CO _s -rich gas mixture from line 5 Λ . The raw gas is introduced into the! Now enters into the CO ₄ absorption process, in which part of the * C () _; - (is first taken up by the methanol. At position 7, where the gas mixture has a temperature of -20 ° C and has a CO. parallel thickness of about 25 ata, it is withdrawn from the column and cooled to 45 "C in the cooling stage consisting of the heat exchangers 8 and 9. The majority of the CO ₂ condenses out. Both heat exchangers are set this high that the condensate flows back under its own gradient together with the gas mixture of the column

pure solvent is fed to the gas mixture. The gas mixture leaves the top of the column 6 at a temperature of 60 _{° C. and a residual content of 1 ppm H 0} S and 20 ppm CCi.,.

The solution which runs out of the CO. One part is returned through line 10 into the column section (itt . The remaining part is cooled to 30 ° C in the heat exchanger 11 by an ammonia cooling machine and first into the

ao separator 12 to 25 ata and then into the separator 13 relaxed to about 2 ata. A hydrogen-rich one escapes from the separator 12 through line 14 Gas mixture which is returned to the raw gas via the compressor 15. To this In this way, the hydrogen losses are reduced. The running out of the separator 13, of CO, already largely freed solution now flows through the heat exchanger 9 and is there during the desorption released balls from the gas mixture.

The solution heated in this way is applied to the top of the degassing rot 16 operating at about 2 ata. A central portion of this column is also supplied to the outflowing from the bottom of Absorplionssäule 6 with about 10 ° C, with H ₂ S beladcne solution: This is first in heat exchanger 17 by a foreign Kältcqueile to -30 ⁿ C, by then in the heat exchanger 18 CO., -Richcs gas and finally cooled by decompression to a pressure of 25 ata and separated in the separator 19 from the hydrogen-rich gas released in the process. In order to increase the hydrogen yield, this gas is also added to the raw gas via the compressor 15. The solution leaving the separator 19 opens after further expansion

the pressure of the Entgasungssäulc 16 a Temperatui of about 60 C and is fed into the column 16 in this 7 'stand Line 20 of flowing nitrogen serving as stripping gas is a large part of the dissolved CO., So-

like some If ₁ S released from the solution. The HS-free solution from the CO ₁ absorption stage 6ft which is applied to the top of _{the column 16 retains the IL 1} S carried along by the ascending gas stream, so that the top product of the column 16 is H ₂ S-free CO _{2 diluted with nitrogen} can be taken. This cools the stripping gas in the heat exchanger 21 and is finally released from the system through the heat exchangers 18 and 4 _{together with the CO 2 escaping from the separator 13.}

By degassing the washing liquid, sicii has cooled it to around -65 ° C. The liquid wedge is withdrawn from the column 16 by the pump 22 first of all cools the dci in the heat exchanger 23 Warm regcncration of the alcohol coming in unc then in the heat exchanger that from the dcrr The gas mixture withdrawn from column section 6 ft is finally returned to column 16 at 24

feeds. _{A solution containing H 2} S, which has been largely freed _{of CO 2} , is drawn off from the bottom of the column 16 and fed to the tub regeneration.

In Fig. 2 is only that section of the Verauien shown, which differs from the method according to FIG. 1 differs. The same parts are the same Numerals. The gas mixture is withdrawn from column 6 at 7, in heat exchangers 8 and 9

cooled to such an extent that the CO ₂ partially condenses and then returned to the column 6 via the separator 30. The liquid CO ₂ collected in 30 is fed back into the column via the pump 31 at 32. The advantage of this process variant is that part of the CO ₂ separated off in 30 can be given off as product via line 33.

1 sheet of drawings

209684/320

Claims (1)

1. Process for removing at least one component of a gas mixture from this, by selective absorption with a solvent * - medium in which the heat of solution is dissipated not only through the media involved, but also through the cold released during the subsequent desorption of the absorbed components and through an external cold source is characterized in that the gas mixture is nnndezum
at which the heat of solution Mciücn by the at ckr ρ of the absorbed constituents ^ _by ^ ne fi.mde, as well as a device SJhradfcsesVerfahrens, urchfuhren aes _seIektive n Absoφtίon Ve represents the ^tan ^ i _{Ungs temperature} of the column by heat and ZuÄ ^ S s. SL2 m au Wa ^ e Cngespeia