US1870096A - Manufacture of hydrogen by the partial liquefaction of gaseous mixtures containing the same - Google Patents

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Aug. 2', 1932. G CLA UDE MANUFACTURE OF HYDROGEN BY THE PARTIAL LLZQUEFACTION 0F GASEOUS MIXTURES CONTAINING THE SAME Filed May 4, 1.925

AZ orwey Patented Aug. 2, 1932 UNITED STATES PATENT OFFICE ononons CLAUDE, or PARIS, FRANCE, AssIGNon T soonirn' LAIR LIQUIDE, socntrn ANomE roun LETUDE ET LEXPLOITATION n-ns PRoc'EDns GEORGES CLAUDE,

SIEGE SOCIAL, OF PARIS, FRANCE MANUFACTURE OE HYDROGEN BY THE PARTIAL LIQUEEACTION 0F GASEOUS MIXTURES CONTAINING THE SAME Application filed May 4, 1925, Serial No. 28,028, and in France May 15, 1924.

This invention relates to the manufacture of hydrogen by the partial liquefaction of gaseous mixtures containing the same, such as coke oven gases, ordinary illuminating gas or the like.

It has been observed that owing to the nitrogen generally contained in the gases treated being the most diificultly liquefiable of the constituents other than hydrogen, the m liquid nitrogen which is last produced (namely in the coldest part of the column wherea very low temperature is obtained by the use ofcold expanded hydrogen) subj ects the residual compressed gases to a washing which efiectively completes the elimination of the carbon monoxide.

It has also been observed that by adding to the compressed hydrogen (which constitutes the residual gas from the liquefaction process) prior to its expansion with the external work, a certain proportion of cold compressed nitrogen, this nitrogen liquefies at the end of each expansion and serves to ensure the lubrication-of the expansion engine.

The object of the present invention is to improve the washing of the residual compressed gases with liquid nitrogen, especially in the case when the gases treated contain I but little nitrogen, by utilizing therefor the 0 nitrogen required for the lubrication of the expansion engine.

According to the present invention in processes for the manufacture of hydrogen by partial liquefaction of mixtures of gases 5 containing the same, such as coke oven gas or ordinary illuminating gas, a method for improving the purity of the as obtained consists in employing for the nal washingof the compressed hydrogen, prior to its expan-' 40 sion, the nitrogen intended for the lubrica tion of the expansion engine wherein the hydrogen is expanded, said nitrogen being pre-- viously liquefied. Preferably the said nitrogen is liquefied and cooled to a temperature ofabout 200 C. or lower.

In order that the said invention may be clearly understood and readily carried into effect, there will now be described one method by way of example of carrying out the process in accordance with the present invention.

The' current of nitrogen required for the lubrication, after an initial cooling in the temperature exchangers, is subjected first if requ. red toan additional cooling in a system charged into a rectifying column provided with Raschig rings or with plates, said column constituting a prolongation of the nest of tubes that supply the compressed residual hydrogen which still contains small quantit es of carbon monoxide. of the very cold liquid nitrogen, a suiiicient quantity of which must of course be used, all the carbon monoxide is retained. The nitrogen, by efi'ecting this liquefaction of the carbon monoxide in the course of its passage through the rectifying column, itself becomes heated and then vaporized. Preferably a suflicient quantity of this washing liquid is employed to allow of an excess of liquid nitrogen rema ning with the carbon monoxide condensed by the saidliquid nitrogen; in this case this excess is discharged into the collector at the bottom of the nest of tubes in which the liquefaction of the greater part of the carbon monoxide takes place. The re mainder of the n trogen, which is vaporized as mentioned above, becomes mixed with the hydrogen and liquefies in the expansion englue, the liquid thus produced acting as a lubricant under normal conditions.

The annexed drawing shows diagrammati- Under the action 7 cally, by way of example, one form-0f apparatus suitable for carrying out the present process.

The gaseous mixture, for instance coke oven gas, arrives in compressed and purified condition at A at the heat-exchanger-B in which it is cooled by the separated gases coming out from the apparatus. -It passes through pipe C at the bottom of the heatexchanger to the bottom of the liquefaction apparatus proper and ascends the tube bundles F, F while liquefying. The two liquids that. collect, one consisting chiefly of methane and the other of carbon monoxide, are raised by pipes D and E and discharged at theex-; terior of bundles F and F to be vaporized. After passlng through tubes F, the compressed gaseous mixture consisting chiefly of hydrogen with small quantities of carbon monoxide and nitrogen enters a rectifyin column G filled with Raschig rings in whic it is washed by liquid nitrogen introduced at the top of the column at H. The purified and very cold hydrogen, which still contains a certain amount of nitrogen, escapes at I and is expanded in the expansion engine K, the lubrication of which is provided for by the nitrogen contained in the expanding gas. The expanded hydrogen from the engine circulates first around the tube bundle L containing the liquid nitrogen that is introduced into the column at H; it then passes around the upper part of the bundle F and then is delivered to the lower ends of the central tubes of the bundle of exchangerB and escapes at the top of the tubes at X. The gas rich in carbon monox de which is vaporized around tubes F passes around the tube bundle M wherein circulates the liquid nitrogen which goes afterwards to bundle L; then this carbon monoxide is joined to the gas rich in methane which is vaporized around tubes F, passes through a part of heat-exchanger B and finally escapes at Y. The compressed gaseous nitrogen arrives at N at the heatexehanger B in which it is cooled and liquefied by the separated gases circulating therethrough; the liquid nitrogen formed passing through a regulating valve 0 which brings it to the pressure necessary for its introduc tion at H into the washing tower or column G after circulation through the tube bundles M and L in which it is su temperatures.

mitted to very low When there is used in column G an ex-' fcessiv e quantity of liquid nitrogen, the excess nitrogen descends with the carbon monoxide of column G through the interior of tubes F and is collected at P with the carbon monoxide and, eventually, the nitrogen which are condensed in tubes F; then the liquid from collector P is discharged through pipe E around the tube bundle F.

Of course, the gas rich in carbon monoxide vaporized around tubes F, and the gas rich in methane vaporized around tubes F, may not be brought together, butmay be circulated separately through the exchanger B.

I claim as my invention:

1. A process for separating the constituents of gaseous mixtures, by partial liquefaction, which comprises expanding with production of external work the residual gaseous product of said liquefaction, using this cold expanded product for liquefying a washing medium, using this liquefied medium for washing the residual gaseous product while still under pressure and using the gaseous medium as lubricant in the above expansion.

2. A process for separating the constituents of gaseous mixtures, by partial liquefaction, .which comprises purifying the residual gaseous roduct of sad liquefaction under pressure y a washing liquid medium, expanding the gaseous product and circulating it in indirect contact with the gaseous mixture under liquefaction immediately before the said purifying step.

3. A process for separating the constituents of gaseous mixtures, by partial liquefaction, which comprises purifying the residual gaseous product of said liquefaction under pressure by a washing liquid medium, expanding the gaseous product, and circulating it in indirect contact first with the washing medium and then with the gaseous mixture under liquefaction immediately before the said purifying step.

4. A process for separating the constituents of gaseous mixtures, by partial liquefaction, which comprises purifyifig the residual gaseous product of said liquefaction un der pressure by a washing liquid medium, thereafter expanding the gaseous product with production of external work, and using the gaseous medium as lubricant in the above expansion. f

5. A process for obtaining a hydrogen-nitrogen mixture in the separation by partial liquefaction of the constituents of gaseous m xture containing hydrogen, which comprises liquefying compressed gaseous nitrogen by the cold expanded hydrogen-nitrogen mixture obtained as the result of the operation, using this liquid nitrogen for washing the compressed residual gaseous product of the separation by liquefaction, expanding. with production of external work the hyd ro gen-nitrogen mixture obtained, and using this cold expanded mixture for the above liquefaction of the nitrogen and for the partial liquefaction of the gaseous mixture.

6. A process of manufacturing hydrogen.

comprising the steps of partially liquefying a gaseous hydrogen-containing mixture. thereby obtaining compressed residual hydrogen; liquefying a current of nitrogen; washing the compressed residual hydrogen with the liquid nitrogen; expanding the washed hydrogen; and circulating said washed bydrogen in indirect contact with the gaseous mixture under liquefaction immediately before the said washing step.

7. A process of manufacturing hydrogen in apparatus including heat-exchanging means and an expansion engine,comprising the steps of partially liquefying a gaseous hydrogen-containing mixture, thereby obtaining compressed residual hydrogen; subjecting a current of'nitrogen to an initial cooling in heat-exchange relation with the separated products and then to an intense final cooling-in heat-exchange relation with expanded hydrogen, whereby the nitrogen is liquefied; washing the compressed residual hydrogen with the coldliquid nitrogen; and

then expanding the washed hydrogen with production of external work.

8. A process for separating gaseous'mixqtures' by partial liquefaction, which comprises cooling to liquefaction the compressed gaseous mixture and a gaseous medium, further cooling the thus liquefied medium by means of separated products, washing under 2 pressure by said cold liquid medium the compressed residual gas of the partial liquefaction, and using the liquid re sulting from said washing in the liquefaction of the gaseous mixture.

9. A process for separating the constituents of gaseous mixtures by liquefying a partof said constituents and expanding the whole amount of non-liquefied constituents, which comprises the steps of totally liquefying a single gas and further cooling the same 'by means of the cold expanded non-liquefied constituents; and washing the said non-liquefied constituents of the gaseous mixture, while still under pressure, with said liquefied and cooled single gas.

10. A process for separating the constituents of gaseous mixtures by liquefying a part of said constituents and expanding the whole amount of non-liquefied constituents, ,which comprises the steps of totally liquefying a single gas and further cooling the same by means of the cold ex panded non-liquefied constituents and the cold separated products of the liquefaction; and washing the said non-liquefied constituents of the gaseous mixture, while still under pressure, with said liquefied and cooled single gas.

11. A process for separating gaseous mix- 7 tures by partial liquefaction, which comprises cooling to liquefaction the compressed gaseous mixture and a gaseous medium \in heat exchange with all the separated products resulting from the separation, further cooling the thus liquefiedmedium by means of cold separated products, and washing under pressure by said cold liquid medium the com pressed residual gas of the partial liquefaction.-

12. A process-of manufacturing hydrogen,

i washed hydrogen in indirect contact with the gaseous mixture under liquefaction immediately before the said washin step.

In testimony whereof I a x my signature.

GEORGES CLAUDE.

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