US2318876A - Liquefaction of chlorine - Google Patents

Description

May 11, 1943. D. R. MEANS LIQUEFACTION OF CHLORINE Filed Oct. 5, 1940 2 Sheets-Sheet 1 Uncondensed Chlorine Liquid Chlorine INVENTOR DWIGHT MEANS BY g y jgw ATTORNEY.

y 1943. D. R. MEANS 2,318,876

LIQUEFACTION 0F CHLORINE Filed Oct. 5, 1940 2 Sheets-Sheet 2 To Secondary Condenser I8 I liquid Liquid overflow ChlormeLeveLU to storage Chlorine q Gas '5 I I I?. L l 3,. I4 v 0:4 flint Interchange:-

Refrigem ted Brine m INVENTOR. V mwem- Mmus BY @wizw ATTORNF Patented Ma, 11, 1943 LIQUEFACTION OF CHLORINE Dwight It. Means, Wadsworth, Ohio, asslgnor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application October 5,1940, Serial No. 359,915 Claims. (o1. (ta-115.5)

This invention relates, to a method of condensing gaseous chlorine. In the usual methods of condensing chlorine, it is often observed that the cooling surface within the condenser becomes coated with a layer of waxy substance to such a degree that the heat transfer capacity of the equipment is greatly reduced. Accordingly, it has been found that such condensers require cleaning at regular intervals. The exact composition of the waxy deposit has not been determined, but

it appears that such deposits are due to the presence of certain organic impurities, generally chlorinated compounds 'such as hexachloro ethane, polychlorobenzene or other chlorohydrocarbons which often occur in gaseous electrolytic chlorine. These impurities are present in low concentration, generally below about 1 percent y weight.

In accordance with the present invention, I have been able to avoid the formation of this objectionable deposit, and thus, to obtain a more eificient operation of the chlorine condensers, I have found that formation of this deposit may be minimized or substantially eliminated by bathing or Washing the cooling surfaces of the condenser with liquid chlorine. This may be done, for example, by causing a stream of liquid chlorine to flow along the cooling'surfaces of the condenser. Alternatively, the cooling surfaces may be immersed in a pool of liquid chlorine.

The invention will be more fully understood by reference to the accompanying drawings, in

which, Y

Fig. 1 is a diagrammatic sectional view of a preferred modification of my invention, and

, Fig. 2 is a flow diagram which diagrammatically illustrate-S a further: modification ofnthe invention.

In accordance with the invention, as illustrated in Fig. l. the condenser I, is provided with cooltions. By maintaining a pool of liquid chlorine of substantial depth in which all or a portion of the cooling coils are immersed, the formation of a waxy deposit, upon the surfaces thereof is thereby prevented. If desired, this pool may be maintained in contact with the entire cooling surface throughout the cooling operations. On the other.

hand, however, this may be unnecessary since the chlorine may be cooled and condensed without utilization of the large pool of liquid chlorine and the-waxy deposit removed from the surfaces periodically by raising the level .of the liquid chlorine sufficiently high to immerse the coated cooling coils and thereby to remove the deposit. Thus, while in the present modification, the liquid chlorine outlet is shown to be above the cooling level, it should be understood that this outlet may be placed at the bottom of the condenser, if desired. 1

The liquid chlorine withdrawn from outlet It will usually contain a substantial portion of the impurities which have been removed from the deposit or' from the iricoming gaseous chlorine. This chlorine may be used as such or, if desired, may be revaporized to leave the waxy impurities in the solid state and the vaporized chlorine may thereafter be condensed in a substantially pure form by any convenient method. The uncon- 'densed chlorine leaving\the-condenser is found to be in a highly purified state and may be condensed by conventional methods. In-the usual practice, the temperature maintained within the condenser is -10 C. The gaseous chlorine is introduced under a pressure of lbs. per sq. in.-

gage and at a temperature of40" C. V

In accordance with the modification diagrammatically illustrated in Fig. 2, I may provide a suitable cooling condenser withheat exchanger l2, havingthe usual brine'inle'ts and outle l3 and M respectively, and chlorine inlets and outlets l5 and I6 respectively. In orderto prevent ing coils I. an inlet for chlorine 8, outlets for withdrawing chlorine 6,. and liquid chlorine Ill. The device is also provided with a suitable manhole 9. I

In the operation of the device, the condenser is filled approximately to the level of the liquid chlorineoutlet with liquid chlorine. Thereafter, gaseous chlorine is introduced through inlet 8, underneath baflle 2, and is allowed to pass in contact with the cooling coils 1, whereby at least a portion of the chlorine is condensed, liquid ch10.-

. tine is withdrawn from time to time through outlet l0, and uncondensed chlorine is withdrawn through outlet 6 for further condensation operaformation of a deposit upon the surfaces of the heat exchanger, a. quantityof chlorine is introduced at H, with gaseous chlorine to be cooled and condensed, whereby a stream 01'- liquid chlorine is caused to flow along a large portion of the cooling surface of the interchanger and is withdrawn with the uncondensed chlorine and liquid chlorine condensed during treatment at IS. The condensed chlorine and uncondensed gaseous chlorine at It is introduced into separator H, wherein gaseous and liquid chlorine are separated.- The uncondensed gaseous chlorine i then introduced into a separate condenser through conduit l8, and liquid chlorine is withing gaseous chlorine through a heat transfer wall at a pressure sufficiently high to insune liquiiaction of at leasta portion of the chlorine and bathing the cooling surface of the wall with liquid chlorine in addition to chlorine which may be condensed upon such surface to prevent accumulation of a waxy deposit upon the surface and recovering cooled gaseous and purified chlorine.

2. A method of treating impure chlorin containing an organic impurity which comprises introducing impure chlorine into a pool of liquid chlorine, cooling the pool by heat transfer through a cooling surface while bathing the cooling surface with said liquid chlorine to prevent accumulation of a wars deposit upon the surface and removing .purified gaseous chlorine from the pool. 3. A method of treating impure chlorine containing an organic impurity which comprises introducing impure chlorine into a pool of liquid and withdrawing impure liquid chlorine from the pool.

4. A method of treating impure gaseous chlorine containing an organic impurity which comprises introducing impure gaseous chlorine beneath thesurface of a pool of liquid chlorine, cooling the pool by heat transfer through a cooling surface while bathing the cooling surface with said liquid chlorine to prevent accumulation of a waxy deposit upon the surface and removing purified gaseous chlorine from the pool.

5. A method which comprises cooling gaseous chlorine containing an organic impurity by heat transfer through a. cooling surface, washing said surface with liquid chlorine in addition to ch10- rine which may be condensed upon such surface whereby accumulation of waxy deposits on said surface is prevented and recovering the cooled aseous chlorine.

DWIGHT R. MEANS.

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