US2211547A - Production of liquefied chlorine gas - Google Patents

Description

J. REICHART 2,211,547

PRODUCTION oF LIQUEFIED cHLoRmE GAs Filed Dec. 21, 1957 2 sheets-sheet 1 Aug. 13, 1940.'

INVEN TOR. j]

BY HIJ ATTORNEYS.

Joseph Rel chart III-Ii l//A ug- V13, 1940. '.J. Rr-:lcHART 2,211,547

PRODUCTIN OF LIQUEFIED CHLORINE GAS Filed Dec. 2l, 1937 2 Sheets-Sheet 2 INVENTOR. Josep/z, Reaczar HIS ATTORN E YS Patente-d Aug. '13, 1940 UNITED sTATEs PATENT vOFFICE PRODUCTION OF CHLOE-.INE

Joseph Reichart, Ludwigshafen-on-the-Rhine.

Germany, assignor to I. G. Farbenindustrie r Aktiengesellschaft, Frankfort'- on the Main, 4

Germany Application December 21, `1937, serial No. 130,977 In Germany November 1, 1933 Claims.

This invention relates to improvementsin the production of liquefied chlorine by compression of chlorine gas.

In the compression of chlorine gas in iron 5 compressors there is the diiiiculty that the chlorine gas readily becomes heated to such high temperatures that the iron is attacked by the chlorine. This attack'commences at 60 C. and increases to such an extent at higher temperatures, as for example 90C. and more, that the compressor is destroyed in a short time. In order to avoid this drawback it has already been proposed to cool the gas to be compressed by spraying liquefied chlorine into the suction pipe and to pass the said cold gas, before its introduction into the cylinder, through a cooling jacket surrounding the same. By this cooling by a gaseous cooling agent, which moveover is only available in an amount limited by the suction zo volume, the heat conveyed to the iron walls of the cylinder and the piston by reason of the gas compression and the piston friction is, however, only'withdrawn very incompletely. The injurious heat may, however, be led away from the Walls muchmore eiliciently by a liquid cooling medium.

According to this invention there is used for leading away the compression and friction heat,

a liquid cooling medium remaining liquid at the4 working temperatures which is cooled by evaporating chlorine or cold chlorine gas or both. Non-aqueous liquids which are not, attacked by chlorine or only attacked with diiculty are es pecially suitable, as for example ice machine oil cooled to 0 C. or less but other oils or organic liquids the solidii'lcation point of which is suiliciently low,'such as chlornaphthalene,may also be used. The liquid cooling medium, after it has preferably been cooled by cold chlorineA gas 40 or liquid chlorine in a device attached directly to the compressor, is pumped through a cooling chamber wholly or partly surrounding the cylinder, the piston and thepiston rod. In this manner such a favorable cooling is obtained that the compression proceeds practically isothermally and thus considerable compression Work is saved.

A suitable form of apparatus in accordance with this vinvention is shown in the accompany-V ing drawings as applied by way of example to a 0 two-stage compressor, but the invention is not restricted to the particular form shown. In the drawings, Fig. 1 is a diagrammatic illustration of an apparatus for conducting my process, the compressor herein being shown in verticalsec. tion in' order to show the details thereof; and

.per side, which leaves only an annular cross-section free, forms the second stage. The cooling medium (cooling oil) is cooled tobelow 0 C. in 10 an oil cooler R by re-evaporated or expanded cold chlorine, supplied from the liquid chlorine storage tank Z the flowV of cold chlorine to the oil cooler being regulated by the valveA V. The cooling oil is kept in circulation by means of the 15 pump P.4 The cooling oil enters at A into the 'cooling jacket surrounding the walls and bottom of the cylinder and leaves the sameat B. The entry of the cooling oil into the piston rod takes place atv E and the exit at H. The chlorine 20 sucked in by the first stage at M and the second stage at O and leaves them at N and T respectively is cooled to about 0 C. before the lsuction valves by sprayedin liquid chlorine or by admixture with cooled chlorinegas coming from the 25 re-evaporation condensers R1 and R2. In the re-eva'poration condensers R1 and Rz the liquefaction of the compressed chlorine is eiected by "cooling by means of liquid chlorine released from pressure. VW is a water cooled condenser. Above 30 the cylinder C (Figure 1) there is' arranged an lauxiliary cylinder G which does not take part in the compression of the chlorine gas itself and which has a cross-section only about 1A; as great as that of the cylinder C. The auxiliary cylinder 35 G, through the cover of which the piston rod of the compressor is ledand on which the main stufviing box F is situated, has an automatic suction valves and an automatic pressure valve D. The suctionv valve S is connected through a suction 4o channel K attached to the auxiliary cylinder direct to the double-walled cover of the main cylinder on which there is situated the suction attachment L for the auxiliary cylinder which is connected with the chlorine re-evaporator Rz forces it to the suction side M of the first stage lof the compressor. By the arrangement Aof the auxiliary cylinder there is obtained a utilization of thecold ot the relatively small amount of re- 55 evaporated chlorine which is released to atmospheric pressure and thereby cooled to below 30 below zero C. and also a complete unloading of the main stuiing box F because the auxiliary cylinder only moves against the suction pressure of the compressor (atmospheric pressure). 'I'he said cooling of the suction gas and the whole cylinder renders it possible in both stages of the compression to select a compression ratio up to more than 1:3 without the average gas temperature in the compressor exceeding 50 C.

`It is preferable to construct the pressure valves of both stages as plate valves and to arrange them closely below the suction valves which are actuated from above. In this Way the pressure valves are also eiiiciently cooled by the flow of the suction gas cooled to C.

'I'he compressor is preferably so arranged that the single stages regulatably suck in independently of each other, the fresh gas supplied thereto from the suction side or from the preceding stage together with a variable amount of reevaporated chlorine supplied to each stage.

The control of the suction valve of the cylinder C and thus the regulation of the compressor is effected in the usual mannerv by variable cams or eccentrics or the like which lift the suction valve over a small or larger part of the compression stroke (for example up to l per cent of the stroke) whereby the capacity of the two stages can be regulated within wide limits.

The regulation of the amounts of re-evaporated chlorine to be supplied to the single stages can be effected automatically by regulating valves V, V1, V2 which are controlled in dependence on the temperature of the re-evaporated chlorine by thermostats.

The regulatable compressor ensures a uniform effect and renders possible any desired delivery not only of liquid chlorine but also of chlorine gas from the intermediate stages under any pressure, as for example for chlorination operations, in which only gaseous chlorine is necessary.

What I claim is:

1. In a process for the liquefaction of chlorine gas by compression, the steps which comprise cooling the cylinder and the piston of the compressor by a circulating liquid cooling mediumV remaining liquid at the working temperatures, cooling the said liquid medium outside the compressor by chlorine in the state of expansion and leading the said chlorine to the suction side of the compressor.

2. In a process for the liquefaction of chlorine gas by compression, the steps which comprise cooling the cylinder and the piston of the compressor by a circulating liquid cooling medium remaining liquid at the working temperatures, cooling the said liquid medium outside the cornpressor by chlorine in the state of expansion and supplying the said chlorine to an auxiliary cylinder situated between the main cylinder and the main stumng box, unloading and cooling the main stuiiing box by the said chlorine and then leading the said chlorine to the suction side of the compressor.

3. In a process for the liquefaction of chlorine gas the steps which comprise compressing chlorine gas in a compressor, cooling the compressor by circulating a liquid cooling medium remaining liquid at the working temperatures in heatexchange relation thereto, cooling said cooling medium by the expansion of chlorine and adding the expanded chlorine to the chlorine supplied to the compressor.

4. In a process for the liquefaction of chlorine gas the steps which comprise compressing chlorine gas in a compressor cooling said compressor by circulating a liquid cooling medium remaining liquid at the working temperatures in heatexchange relation thereto, cooling said cooling medium; by the expansion of chlorine, evaporating liquefied chlorine in order to obtain the cooling effect thereof, leading expanded chlorine in heat-exchange relation to the top of said compressor, and then adding the expanded chlorine to the chlorine supplied to the compressor.

5. In a process for the llquefaction of chlorine gas the steps which comprise compressing chlorine gas in two stages in a compressor, cooling said compressor by circulating a liquid cooling medium in heat exchange relation thereto, cooling said cooling medium by the expansion of liqueiied chlorine,evaporating further quantities of liquefied chlorine in order to obtain the cooling effect thereof, adding some of the thus evaporated chlorine to the expanded chlorine from the cooling of the cooling medium and leading the same in heat exchange relation to the top of said compressor and then adding the same to the chlorine supplied to the4 first stage of the compressor, leading the compressed chlorine from the 'rst stage of the compressor to the inlet of the second stage, adding the remainder of said evaporated chlorine to said compressed chlorine, compressing the chlorine in the second stage of the compressor. and cooling the compressed chlorine from the second stage of the compressor in order to liquefy the same.

JOSEPH REICHART.

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