USRE18563E - Signors to w - Google Patents

Description

9, 1932. 3, COOPER AL Re. 18,563

DEHYDRATION OP FUEL GASE Original Filed Jan. 30; 1926 INVNTQRS C.COOPER g0. M. HEN SHAW R lLL. i.

Reiaued Aug. 9, 1932 UNITED STATES PATENT OFFICE I CHARLES COOPER AND DANIEL MAYON HEN SHAW, OF HUI DDERSFIELD, ENGLAND, LIMITED, OF HUDDERSFIELD, ENGLAND.

SIGNOBB TO W. C. HOLMES ANDCOMPANY,

DEHYDRATION or FUEL GASES Original No. 1,614,347, dated January 11, 1927, Serial No; 85,044, filed January 30, 1926, and in Great Britain December 11, 1924. Application for reissue filed January 2, 1929. Serial No. 329,857.

This invention relates to the manufacture of fuel gases. 7

As is well known, mains used for conveying fuel gases become corroded relatively q rapidly and particularly in cases Where the oxygen content of the gas is somewhat high, or where other bodies promoting corrosion are present therein.

Of the several bodies present in fuel gas to which the corrosion may be attributed, sulphur compounds, cyanogen compounds, carbon dioxide, oxygen and water may be cited.

The invention is based upon the observa tion that the corrosive action of some of all of the constituents of fuel gases to which the corrosion may be attributed may be minimized or inhibited by the reduction in moisture content of the gas, our experiments appearing to indicate that the desired result may be secured if the content of water vapour in the gas is reduced to such an extent that deposition of water in the pipes cannot occur, by subiecting fuel gases preferably at the normal pressures under which such gases are distributed and under temperatures not materially below atmospheric temperature to the action of hygroscopic or water-absorbing bodies in the liquid state with preferablv the continuous or intermittent treatment of the hygroscopic material to convert it. by the expulsion of the absorbed water, into the condition in which it may be used in the treatment of further quantities of gas.

Convenientlv for brin sing the gas and absorbent material into intimate contact when employing a hvgroscopic liquid. a so-called brush-washer of the character described, for instance. in the specification of British Patent No, 162,166. is employed but it will be understood that the invention is not limited in this respect.

The drying operation may be of such character as to effect substantially complete removal of the water, or to secure such a reduction in the moisture content that deposition of water within the mains is prevented, or to secure that on the average the dew point of the gas is such that any moisture separating due to cooling will subsequently be evaporated, or to the reduction of the moisture content to a degree which will render the removal of a of moisture by other means, for instance, by the use of reagents such as silica gel, commercially practicable or economical. Referring to the third procedure set forth in the preceding paragraph, it will be obvious that since the gas has thus been partially dehydrated but not to such degree as to pre cent any deposition at all of moisture'at any point in the mains (as in the first andseoond instances mentioned) such cooling as will cause deposition, in the said third instance, can only take place at points of minimum temperature in the distributing mains.

It will also be obvious that while in this instance the gas is dehydrated eventually prevent the presence of moisture in the mains, consistently with the general object of the invention as a whole, nevertheless the gas is not' dehydrated to such extent as to be capable of picking up'excessiveamounts of moisture from the mains and thus causing an excessively rapid dying out of the mains, which is undesirable for many reasons.

Where moisture-absorbing material .em-

ployed in such further treatment of the gas is of a solid character, the procedure and apparatus forming the subject-matter of the application for British Patent No. 162,166 mav be adopted. v

The treatment to secure thesevarious degrees may-vary in intensity or in the means employed .or-in the material, used as the dehydrating substance. For example,- for a partial removal it might be sufficient to employ a solution in water of a substance not recognized as hygroscopic, as it is known that the vapour pressure of such-a solution is in general lower than that of waterv at the same temperature. Such a solution is to be considered included in the following .de-:

scription under the term hygroscopic or water-absorbing material.

Anarrangementof apparatus for carrying the invention into effect is illustrated sufficiently to a diagrammatically and by way of example in the accompanying drawing, in which z- Figure 1 is a side elevation, and Figure 2 is a view in plan. I In the drawing, A is the brush-washer, B

the inlet and (Hills outlet for the liquid employed. A solution of calcium chloride is prepared in the tank D and pumped into the ofthe pinup E connected to the inlet B. The liquid reservoir of the washer is filled with a solution of such concentration as will give desired results by virtoe of its partial pressure of water vapour.

Dilution occurs in the liquid due to the absor tion of water from the gas.

- furtherquantity of solutionis now added and it is obvious that the quantit is deterlined by the necessity for reproducing the conditions, or making a permanent cyc e 01 rations. I

The uted liquor is partially displaced from the washer and passes from the outlet G into the tank F. When the operation of intnoducing the fresh material is completed the pump is employed tocirculate the diluted solutim as follows; i

A continuous. stream of the liquid is (I through a. pipe line G, G,,returnmg the tankF,anditisarr edsotbata smaller stream can be tapped o intoa trough H perforations or serrated edges to Va a reasonably uniform distribution oi liquid along its Icngth.- This arrangement is an plicatlon of known devices. The (Iiior divided streamsare allowed to trickle down over horizontally laid tubes .1, verti call over each other, and connected together at ends to form aconduit for the heating medium, for instance live or exhaust steam. The heated liquid is deprived of a portion of its water content by exposure to the air in this manner and returns to the tankF. 'In course of time a concentration is reached which is suitable for the fresh liquid'entering the washer. Duringthe last stages therefor the regenerated liquid is gradually transferred to'the other tank I) so as to leave the tank F fees for the next charge. of diluted solution- The regenerated solution may be cooled by any suitable means if desired before being pumped into the washer again.

l't Is evident that the periodical introductron of fresh absorbin liquid maybe substia continuous ow of liquid. For example, the overflowing diluted solution may be to'pass through the concentration immediately on leaving the washer and may be further continuously repumped th the wlsher'imlet, the rate of operation of a this pump venting the rate of circulation granny. uch pump may conveniently be ven by any power unit driving the mechanism of the washer.

Such a continuous circulation would be 'mitedtos'uchtypesofgaswasmdesigned to contain only a small quantity of wash liquor at a time, whereas the type mentioned in the above detailed description has relatively lar e reservoirs for liquid.

Such modi ations of practice do not afiect the principle of the invention nor does the introduction in either the first or the alternative methods of storage tanks to retain a stock of strong or diluted absorbent, or the introduction of cooling devices for the liquid.

Instead of the construction of evaporator referred to in the above detailed description,

. any other convenient form of evaporator may be employed.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is 1- The process of treating industrial fuel gases prior to transportation in the mains which comprises, subjecting said gases to the action of hygroscopic or Water-absorbing bodies in the liquid state until the moisture content of the gas has been reduced merely to such degree that on the average the dew int of the gas is such that moisture separated from thegas by cooling at points of minimum temperature in the mains will subsequently be evaporated by the gas, whereby permanent deposition of moisture is prevented and corrosion oi the mains inhibited without an excessively rapid drying out of the mains.

2. The process oi treating industrial fuel gases prior to transportation in the mains which comprises, dehydrating said gases until the moisture content of the gas has been reduced merely to such degree that on the aver-. age the dew point. of the gas is such thatmois ture separated from the gas by cooling at points of minimum temperature in the main will subsequently be evaporated by the gas, whereby ermanent deposition of moisture is prevented and corrosion of the mainsinhibitcd without an excessively rapid dryingout ofthe mains. 7

CHARLES COOPER. DANIEL MAYON HENSHAW.

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