[1]v 7 39080,442 Ljiilted States Patent Office Peg@-ente-d Mar. 5, 1963 3,080,442 APPARATUS AIND PROCESS FOR TI-IE4 CONVEi RSIGr,4 OF HEA-T TO ELECTRICITY P.1e;-@a-rd 11. I-lobert, Wam,@nhomssic Point, R.F.D. 1, 5 Stanington, Conu. Ftled Dec. 30, 1957, Ser. No. 706,165 6 Claizris. (Cl. 136-86) This invention relates to apparattis and processes of converting tj-iermal energy to electrical energy. 10 ,On-- obiect of triis invention is to proyide - apparatus and a pro,-es,3 for coiiverting thermal ener-Y to chemical energy and thenc.- directly into electrical energy without requiring the use of steam turbines, driving mechanical elecl,ical @enerators, as has heretofore -been customary. 15 Ano'cher object is to provide apparatus and a process for coiiverting tliermal ener.-Y to electrical energy wherein heat from a suitable external source is employed to dissociate a chemical compourid, such as water, into it@ cor-nponent gases, whicli gases are then separated from 20 one another and recombined in a so-called fuel cell containing electrodes which give off electricity generated as the result of the recombh-iation o-@' the gases. Ai,,other object is to provide an apparatus and process for converting thermal energy to electrical energy wherein 25 the chemical compound produced by re-combination of the component ,ases in the fuel cell is returned to the dissociation devic.- for repeated dissociation, thereby re-iitilizin- tfie chemical compourid as a working fluid 1;1 in a cyclical@ process and cyclically-operating apparatus. 30 Another object is to provide an apparatus and process oi'. converting thermal energy to electrical energy wherein beat remairivig in the componeiit gases of the working fluid or chemical compound after dissociation and separation is transmitted from ti-ie -ases before entry into the 35 ftiel cell to tile recombined working fluid or chemical compoul.qd returnin@ from the cell on its way back to the dissociation device. Another object is to provide an apparatus and process of converting thermal energy to electrical energy which 40 possess a hi.-h operating efficiency of energy conversion which can approach that of a Carnot cycle heat engine c,peratin,,y betw,,en the same temperature limits. The draw;ng illustrates diagrammatically one form of apparatus accordipg to the inventior, in which the process 45 of converting thermal e-nera.Y to electrical energy can be carried out, according to the itivention. The dravving in gene,,,al sho@vs diagrammatically a thermal-to-electrical eiiergy-conversion apparatus, gen- 50 ora'ly desigr@ated l'u, by which a working fluid, such as water, convertecl into steam by the application of heat, is partially dissociated by heat from an external source 12 in a ther@iial water d;ssociator 14 into its component gases hydrogen and oxygen, t@fle mixture of which is 55 partially serarated into hydro.-eii -as and a mixture of ox,7,pen aiid water vapor in a gas separator 16 which may be assisted by a-@i alixiliary external source of heat 18. The hydrogen-enriched and oxygen-enriched gases, separated from on@- aiather in ttia separator 16 are pumped through hydrogen and oxy,@en heat exchangers 20 and 60 22 re,.zpectively to impart their heat to retur-@iing working flu-id, after which the gases are passed th@-ou-h a gas cooler 24, the vvater be,@'ng returned to the returning workiiig fluid throu.-h a water disposal unit 26, after wliich the hydroaen and oxygen gas s are separately fed into e' 65 an electro-cheiiical fvkel cell 23 where they are recombined into water, @vith electricity -iven off as a result of this reaction. The water evol@ved in the fuel cell 28 weakens the electrolyte therein, hence the excess water 70 is separaled from the electrolyte in an electrolyte water remover 30 from which the electrolyte is retiirned to the 2 fuel cell 23 and the water through the heat exchangers 20 and 22 back to the thermal dissociator 14, as described in more detail below. Referring to the drawing in detail, the dissociator 14 receives water initially, and superheated steam subseque-itly through a steam supply or return pipe 32 and, in response to intense heat supplied by the external heat source 12, coiiverts a part of this water or steam i'@ito hydrogen and oxygen gases, mixed with steam. The percentage of water dissociated in the dissociator 14 depends upon th.- tempe.-ature and pressure at which dissociation takes place. The following table, for example, indicates the percentage of water d-issociated at varying absolute temperatures in de,- rees Kelvin at various pressures in atmospheres, as calculated from theory and given in Table 8 on page 32 of Chapter IB of the book "Properties of Ordinary WaterSubstance," by Dorsey, published by the Reinhold Publishing Co., of New York, N.Y., as No. 81 of the American Chemical Society Monograph Series. Te-,npera- Pressure (atiiio,,I)heres) ture (degrees K.) 0.1 1.0 10.0 1, 5(0 0.0434 0.0202 0.00936 2,000 1.25 0.579 0.269 2,500 5.77 4.17 1.96 3,000 27.7 14.1 6.85 The same textbook also gives the followin-. observed values of dissociation for different te@nperatures at atmospheric pressure. Percentage Temperature (degrees K.): dissociation 17003 ---------------------------------- 0.182 1863 ---------------------------------- 0.354 1968 ---------------------------------- 0.518 2155 ---------------------------------- 1.18 2257 ---------------------------------- 1.77 1)337 ---------------------------------- 2.8 2505 ---------------------------------- 4.5 Since the dissociatioii of the water into hydrogen and oxygen takes place simply by eievating the temperati-,re while maintaining a low pressure, dif.Lerent forms of dissociators may be used according to the space and wei-ht requirer@ients and efficiency ar@d cost elements irivolv'ed. The dissociator 14 is therefore shoivn in a diagrammatic form for ease of understandin- as consisting of a casitig 34 contai-iiing a partition 36 S'e'parating it into a heater chamber 38 containing the heater 12 and a dissociation chamber 49 in which dissociation takes place. From fne dissociator 14, the pipe 42 carries the mixture of hydrogen gas, oxygen gas and water in the form of steam or water vapor into the gas separator 16. This also in the drawing is shown as a single housing 44 containing low.-r and upper chambers 46 and 43 separated from cne another by a so-called gas diffusion membrane 50 consisting of a wall of maerial having very fine pores m,hich allow passage of the 'Molecules of the gases, but vihich net much as small individual orifi,-es so that the assage of the molecules through the membrane is rep strieted, and a pressure difference can be maintained between the chambers 46 and 48 by mealis of pumps or compressors 52 and 86. The material of the diffusion membrane or barrier 50 is not crilical and various types of porous high teir@perature ceramic membranes or barr.,ers are known to those skilled in this art and are available on the market. Their idetails are conventional and
[2]@@-3)080,442 3 ard,beyo-nd:the scope of the present invention. Since the velocity of effusion of molecules tlirough small -orifices or diffusion membranes is inversely proportional to the square root of the molecular wei.-ht of the gases, at least on@ a statistical basis when@. the --bases are -at a, constanttemperature and.pressure,:the:@hydro,aen mol@ecules will pass through the membrane with a -greater velocity than @the oxygen and @water@molecules. Due, howev--r' to the great abundance of water molecules in the gas, since o.,ily a small@percentage of the water is dissociated, water ,w-olecules will also pass through the membrane in conisiderabl-. numbers. Hence, the, gas . extracted -through the pipe 54,will consist of hydrogen and.,water molecules and a small @ amount -of oxygeii. The, auxiliary source: of beat supply IS ;may receive heat from the: same main source of heat stipply @ 12, and effects @ additional dissociation while gas separation by diffusion is taking- place. , @While the@drawing, for purposes of simplification, shows only :a single-stage gas separator 16, it -will :be understood that;in practice, multiple stages may @be used. Furthermore,% to decrease the partial pressure of the hydrogen in @the upperchamber 48 without requiring a large@ pres@.ure drop across the @ diffusion membrane @ 50, an . inert gas may be introduced into the upper chamber 48. @This inert gas, of any suitable character, must either be re,moved from the working fluid before entering the cell 28 or it must be vented from the cell. . In either case, this gas can then be recirculated to the chamber'48 through appropriate pressure-reducin.- valves. This gas @ does not need to be inert, but it must be possible to separate the hydrogen, gas therefrom without req-airing large@ amounts of ener.-Y or equipment. The use ;of such gas is optional, and the 1 separation process can be maintained without it, hence the equipment for handling such a -as has not been indicated in the accompanying drawin.a. Such separation.of gases by means of diffusion is known to physical chemists and is described, for example, in the bobk "Textbook on 'Physical Chemistry," by Samuel Glasstone, Van Nostrand, New York, Second Edition, 1946, page 153 of which describes membrane diffusion including the separation of isotopes by di@'fusion metbods and page 154 of which describes thermal- diffusion methods; Also the book "Soureebook on Atomic Energy," by the .@ same author and publisher (-1950), pages 200 to 204, "The Gaseous@ Diffusion -Methods"; also the book "Atomic Eiiergy forMilitary -Purposes,"- by H. B.. Sm th, I Y Princeton University,-Press, 1945,-pages 158-159 and 175-186 in Chaper-XI "The Separation-of -the Uranium Isotopes by Gaseous Diffusion." The hydrogen gas from the,hydrogen chamber 48 of the gas. separator 44 is pumped by a suitable pum]@ 52 through a pipe 54 and heat exchange coil 56 within the hydrogen heat exchanger 20 by way of a pipe 57 containing a valve 53 to a coolin.- coil 60 within the gas cooler'24. A coolant enters the coolant chamber,66 whi-.h.is enclosed within the casin@ 62 by means of a coolant supply pipe 64. A discharge pipe 68 cohducts the now-warm. coblant out of the chamber 66. The purpose of the, gas cooler is three-fold. It furnishes a, mechanism. for rejecting waste heat -to the at@no'sphere or,other.convenient heat sink, it cools the component gases to facilitate.the removal of a large portion of the entrained water vapor, and it reduces -the temperature of the component gases to temperatures compatible - with the requirements of the fu@l cell, and to maintain the appropriate temperature differences reqtiired in the operating system. The nature 611 the coolant will, in general, depend on the application. For example, atmospheric air could beused.directly for certain applications, whereas water or. low temperature steam mi..ht prove attractive in others. The techniques of heat rejection are well known to mechan;cal engineers and are beyond the scope of the present invention. The need for a. gas cooler @ is evident from the second law of th-_rmo.dynamics. The thermal efficiency of the over-all energyconversion proeess cannot exceed@ that of an, ideal Carnot cycle engine operating between the same teniperature limits,,and this efficiency E can be expressed-as: T2-Ti E@- where T2 is the@absblute temperature@atiwhich@thermal energy is supplied Ti is the absolute temperatlire at which thermal energy 10 is rejectdd E is the ideal thermal efficiency. From , this @ @it @ is evident - that - a certain fraction of the energy which is supplied @must be r@,jected as waste heat, 1 5 @nd -that. this, fraction. is I -E in the ideal case. . But since -T2 20 this -is- an @equivalent;@ expression @ for the fraction of: th-therm@l energy which; must be, rejected. Due to other efficien ' cy @ losses in @ @,the @ system, the thermal energy re. jected Will.@be.a lar,-er. fra:ction of the thermal energy sup. plied. iThe@-gas cooler.@-24 rejects excess energy and pre25 vents@overheating@,ofthe:system like:the coolin-@systems on conventional,heat@engines. From:thermodynamic considerations, the.- temperature@ of @energy rejection should be as.low,.as .possible -@in order to achieve- the maximum efficiency, hence@.the @cell i2S:. should therefore operate at or 30 near the@ temperature 6f energy rejection, whereas from electrochemical' considerations it must operate at a;moderate - temperature in ord-@r @to increase the rate of reaction so @that @the@-. size,. weight @and cost of: the ctll 23 can be,kept @withim reasonable limits. Since @the gas cooler 24 35 does @not-.need. to.@operate at a temperature much lower thanthe temperature.of operation of the cell 23, other than:thetemperature differences required for condensation 'in the.- cool.-r @: 24, and as a means of controlling the teinperature- within the cell 28, the temp@,rature at which 10 heat is rejected:is relativoly high if the Bacon cell is used as the@@cell,. 28. The 'hydrogen;to be cooled is pumped through the coil 60 by a pu.,np 70, which cooling reduces its.-.temperature::to a temperature suitable for handling within the @electrochemical cell 28 and at the san-te time 45 removes water vapor by con-densing it to liquid water. The hydrogen thus-cooled passes through a tank 71, pipe 72, valve 74@@and pipe 76 to the fuel cell 28. The water condensed;from thd hydrogen in the coil 60 is drained @off through:,a.,port 83 controlled by a float valve 85 and 50 through al@pipe 78 and check valvd 80 into a pipe 82 leading to a return line 84. Meanwhile,@.the,mixture of oxygen gas and water vapor left,-in,,the@ -lower chamber !46.bf @the gas separator 44 is pumped by- a, punip-86 throu.-h; a,pipe 38 into a heat ex55 cbange@,coil@;..90@@witbin the oxygen heat @exchanger 22 whence it is @pumped by a pump @93 through a pipe 92 and valve-@,94,.-into - an:oxy,@en,cooling;coil @96 also located in the coo lingchamber.@66:of the @gas cooler,24. The oxygen @thus: cooled passcg through.a tank 99, pipe 100 valve 60 10.2:@alid@pipe.-,104 to @the fuel cell@28. ' The water coiidensed. from the oxygen in the, cooling coil 96 @is drained off tlirouo,h a @port-103; controlled by a@ float valve 105 and through@ a- pipe, 106 and -check valve 1 0,8 into the pipe 82 and thence @ into. the return pipe 84 ' Surge tanks 110 65 and 112 respectively@are connected bY Pipes 114 and 116 to the pipes 72 and 100 immediately ahead of the valves 74 and 102 respectively. The electrochemical fuel @cell .28 in which the hydrogen and oxygen gases @ are :recombined,, accompanied by the 70 emission@ of electricity, is shown diagrammeit,cally in @the drawin- as: itsi details are coiiventional aiid,h-@nce are beyond the scope of @ the, present invention. One suitable fuel cell for this@ptirpose is -knonvn as the Bacon fuel cell invented in. En land by Francis T. Bacon. and disclosed @ 9 75 and claimed.in,-the.Bacon Patent@ 2,716,670. of August-. 30,
[3]19,55, for Alkaline Prii-nary Cells, and a.Iso described by A. Adams in the journal "Cheniical and Process E-,i-,ineering," 35:1 (1954). The BF;.con fuel cell 23 consists @.-.nerally of a cloq.-d and gas-tight tious;, - 120 hal,,ing on opposite sides thereof vertical liydrogen and oxygen gas passageways il22 and 124 -e@-pectively extending from top to bottom and ha-ving itilet ports 126 and 128 Ft Vri-e top. Arra-.,F,,ed within tre housing 120 are t@vo laterallyspaced poro,,ls nickel electrode structures 134 and 136 r,-spectively spaced apart from and insulated 'Lrom one aiiother and from the housi,.ag 120, the spacing therebetween providing a vertical central electrolyte passageway 138 having an outlet port .142 at the top and an inlet port 140 at the bottom. Th.- hydrogen supp'y pip-- 76 is connect-d to the hydroge-.i inlet port 126 of the elec@rocher@iical cell 28. Similarly, the oxygen supply pipe 104 is co,@inected to the oxygen inlet port 120. Conceritrated electrol@Yte is supplied to the cell throu-.h the electrolyte sup]@ly pipe 156 which is attached to the inlet port 140. The electrolyt-- is puti-iped through the electrolyte supply pipe 156 fro,@-a the electrolyte water remw,,er 39 by a 7,imp 152, whereas an 'ectrol ei yte return pipe 158 rv,.ns from the electrolyte outlet port 142 back to the electrolyte water reiiaov,,r 39 iiliile the pressure is reduced by a throttling v,-Ive 154 to facilitate the evaporation of excess water in the electrolyte water remover. From the latcer, the rettirn pipe 84 containing tfie pumps 16@3 and 162 and the check valive 164 rurs.back to beat exchange coils 166 and 163 within the hydrogeli heat exchanger 20 and oxy-,en heat exchanger resp-, etively, the@ e being provided with valves 170 aiid 'I.72 between them and the return pipe 84. A sur-.e tar-lk 174 is conilected by a pipe 176 to the return pipe 81, between the pump 160 ai-id check valve 164 and a drain pipe 178 is likew:@se connected to tli-- return pipe 84 and p@-ovided with a drain valve 180 for draining the pipe 84. From the opposit@- ends of the heat exchange coils 166 and 168 the steam return or supply p:ipe 32 ruiis back to tl-.e dissociation chamber 40 of the therinal w,)@er dissociator 14 by way of a valve 182, completipg tl-le circuit. A pressure relief valve 184 is coniiected by a p@pe 186 to the steam rellurn or supp'IY p@'@pe 32. Mult-IP!e c-.11 arrays or batceries of tl-ic cells 29 rray b@provided to furnish hi,-.her volta.-es b,v eleelrically c@,nnecting the cell 28 -in series, e-.-@id to fur-@iish larc,,er currents by electricall@r connecting the cells 2'0 iii Darallel. L-i any case, the ftiel gases c,,in be stippl:ied to the cel-s by pipe lines in a "parallel" arrang,-merit, aiid 'che eiect-olyte c@,in be wicndravin and recire-alated t,irougii a commo-,l water ren-iover 3a in oost cases. Special provision should be r-qade for the isolatior, of the electrolyte from grol,ps of cells 28 if a great -@nary of fie cells 23 were arranged in series. Th:s arran,@em-,iit of rntiltiple cells would use common irlpi:,ts from common I-eat exchangers. In the operatio@-1 of the apparatus 10 and in the c-@ri,ying out of t'@ic process o'L the irive.- @tio-@i, and assurialn.-, for 6xample (but rot by way ol limitation), that the fuc-I cell 28 is of the so-callect Bacoil type, a 27% potassiiim hydrox:LLic aqueotis soltition is supplied to the electrolyte passageway 138 of the fuel cell 29@ and circulated by fne pump 152 and aided iii its flow by tliemosyphon aclion Lipward througl-i the passageway -il.38. At t'.-..e saiiie tilii--, a coolant such as water which is tised for tl,.e remov,-,! of waste heat, is sup ied frorn an exlernal source (not Pi shown) thre-tigh the pipe 64 to the -is cool,-r 24. Water or steam is iiiiiidly suppl.-ied through the stearn supply pipe 32 to the dissoc;a'@ion chamber of the water dissociator 14 ,@ih@@le heat from the heater 12 act@. upon tN stcain ia the chamber 4,a to coilvert it to , mixture of hydrogei@ (H2), oxygen (02) aid steam or wat,.r vapor (H20). In accordati@;e with the table given above, the temperat-Lire within the dissociator chamber 4@,l is maintained as high as possible and the pressure as low -,s practical, pref,-rably below 10 atmospheres, in order to oblain th-- rraxinur@i percentage of d-"ssociation. 'nis irixttire 3,080,442 6 flows tlirough the pipe 42 iito the lower chamber 46 of the gas separ-@tor 1.6@ where fiirth-,r dissociation is assisted by heat from the auxiliary h-,ater 18, the flow beiiig enhanced by the action of the pumps 52 and 86. The high velocity fiydrogeia nioleclil-.s pass rapidly tilrough the pores of tne diffusion m.-mbrane SO, where-,is the oxygen and v@,ater molecules, by virtue of their hi.-her molecular weights, ar@- travelin-. at much slower velocities, and hence a smaller fraction of th-- total nunib@r of oxygen and water molecules pass through the 10 membra-@ie ii any c,,;ven time period. 'I'he action of the membrane 50 provides a nieans for sepprating, to some exte-@it, the molecules in a mixed gas, on tf.,e basis of their molec,.Liar weights. Since the hydrogen i-no,e-,ules which pass through the i-nembran-, 50 and en'Ler the chamber 43 15 deplete the amount of hydrogen iii the niixed -as in the chainber 46, there is a chan.-e in the partial presstires or the mixed -.ases in the chamber 46. This favors the further dissociaticii of the water molecl,.Ies contained iii these mixed gases provided thal sufficient theriiial energy 20 is added, as for example, by the auxiliary heater 18. Thus, the fraction of water admitted to the dissociation chamber and separator, which is dissociated, may b@larger than the value given in the dissociation products listed in the ttble above provided that the products of 25 dissociatio-@i are withdrawn, and that the press,,ires in chambers -46 and 48 are maiiitained at their proper values by means of ti-ic plmps 86 and 52 respectively, by means of 'Lhe adjusting val,,,e 192, and by furnishing sufficieit thermal energy by heaters 12 and '18. It will also 30 be apparent to physical cliemists thnt the degree of yarity can be improved by us,'@ng mult-iple sta,-Cs of dif-fi-ision sepai-ators (,not showii) and that other means illpy be used to achieve or accelerate the separation of mixed gas,-s. The membrane dif:usion separator 50 used in 35 the illustration indicates one method wliich has been found attractive wiien one of the mixed gases is liydrogeri. OtL-er means of separatioi ipcl@ude but are not limited to: changes of state, differential solubiiity in other 40 fi-uids, a@@id intermediate chemical reactions with siibseqiient decomposition facilitating the above niethods. The oxyg,-n molecules and water vapor are pumped by the nunip 86 through the pine 88 and heat exchanger coil 90,- w@iere the liot mixture g:tvcs up heat to the re45 turni'@ig steam passiiig throu.-h the coil 168 iii the opposite directio,). The oxy-e-@i, thiis reduced, i-@i temperature, is plniped by the piimp 98 thro-,ign tne pipe 92 and r@ow-oden valve 94 throu@,,h the cooli.,i.- coil 96 wh.-re its water -vapor is conde,.ised into water and passes throu,-Il 50 the tar@k 99, port 103, when open, pipes 106 and 32 and ch,--ck valve 108 into the return line 84. The oxygen, thus fre-.d from water, passes through pipes 100 and 104 and the now-open valve 102 through the oxy-en iiilct port 123 and oxyg.-n passa.@eway 124 of 'Lbe fuel' cell 28, 55 where it passes throu.,-h the pores of the Doro,,is eiectrode 136 to the electrolyte in the electrolyte passageway 138. Mear,-vi,h;le, the hydrogen gas -,Nihich has passed throu---h the diffusion rnembrare 50 of the gos separator 16 in'to 6( the upper chamber 48 thereof has been pump.-d by the pump 52 throtigh the pipe 54 into the heat e),change co;j 56 of the hydrogen heat exchan-er 20, where it gives t,.p he,@t to the returiiii@ water or @water vknor passirg in the opposite direction'throti-h the licat exchange coil 65 166 to the steam return a-@id supply p;pe 32. The byd-rogen gas, thus redticed iii temperature, is pumped by the pamp 70 tliroj,-h the pipe 57 ar@d now-ope-.i valve 58 throtigh ttie cooli@-ig @.oil 60 v@hence the ivater candensed th.refro@n passes tilrough the taiik 71 and port 83, when 70 open, into the pipe 78. The hydrogen, thilis freed from water, passes throil-a,h the pipes 72 apd 76@, the now-open valve 74 and the hydrogen inlet port 126 into the hydron passa-eway 122 where it passes through the pores of the nickel diffusion electrode 134 to the potassium 75 hydroyide electrolyte passiig upv;prd through the elec-
[4]7 trolytepassageway.138. Meanwhile, any traces-,of water vapor whiqh may, have. accoriipanied the hydrogen gas through the dii'jusion membrane 50 of the:gas s,- parator 16 are condensed to liquid water, which@-flows dow-riw,zrd tlirough @.the, pip-.s @ 73 . and ' 3Z.and the check.yalve 00 to ,the,-vvater return pipe 84. The hydrogen and oxygen are introduced into the clec-jtrochemical fuel@ cell .28 ;in the molectilar pro@ortions 2: I @ and.eventually combine within the cell in a manner :known to @electrochemists,and @described i-@i Bacon Ur@ited .States Patent No. 2,716,670 of August 30, 1955 to form 10 ,ivater,:hence.the details thereof are.coiiventional and accordingly -beyond the scope @of the present invention. The water thus formed dilutes the electrolyte in the-cell, :and tlie diluted clectr6lyte. is. removed through ithe elee@trolyte. outlet port,142 through the pipe 158@ and valve 15 154,into the water remover 30 where the excess i wat,-r..is iemoved 'through the pipe @ 84 and the @electrolyte, once .again at ilts initial concentration,. re-enters the cell ' 28 ithrough@ the. pipe .156@,aLd,.pump 152 by means of the 20 ,electrolyte inlet port 140. The reactions within the. ceil ,are -.accoinpanied @ by: tbe: evolution of eleetrical energy and. some.heat. @The electrical eper,@y is the useful end' .product of the cycle, and is conve ed to iLs ultimate use @by means -of -the electrical conductors 192 and :194. Despite, the -fact -that @heat is evolved,i,.l the bittery, its tem- 25 .perature is @maintai-@ied @at favorable operating conditions by means of controlling the temperatures of thei fuel -ases -w.hich, are introduced, and by means of heat removal ,f , -rom the -electrolytein the -water remover. A cell heater @(not'shown) imay:.also beused to heat the fuel cell 2,3 30 -so - as @ to maintain the proder cell temperature under transic,it,conditions when heat may @@be required, as for .example when starting the system. . As @ a result of this @ action, by withdranval @of electrons 35 .from @the oxygen electrode 136 and depos'ition of electrons.. on the hydrogen: electrode @ 134, a @.flow of electric -current takes iplace through @the co-@iductors 192 and 194 and the external circuit from the hydrogen electrode -134 back, to the oxygen electrode 136. @ The' fuel cell 28 40 during this operation;is preferably operated at pressures of 40 to :55 atmospheres (approximately @QO to @ 800 pounds per square inch)- at temperatures preferably lyin.a between 392' F. and 464' F. (200' C. and 240' C.), -the cell giving an open circuit voltage output of 1-05 volts 45 at-the above-named temperat,,ire ,ind pressure. Meanwhile, ihe water@produced within the cell 28 by ;the above@ action:dilutes the electrolyte. flowing through :the electrolyte- passageway 133 @ at:a relatively slow rate, -the clectrolvte beina kept from excessive dilution ..by 50 ,the @ action 6f the water remover 30, N@,hich extracts water from the ;electrolyte., atid returns it throu.-h the return pipe 84,,containing @the pump 160 and check valve 164 and ',hence -through the heat exchange coils 166 and 168 and tlle steam return pipe @ 32 to @the@ water dissociator: 14, 55 completing the circuit. 11, will be evident to those skilled in the fuel cellart tilat pressure-regulating vaINes,@ relief valves, vents and condensate traps may be added to the ci@-cuit shown@ in the drawing for more improved op.-ration aid control of 60 the gas pressure at the various locations. After operation has once commenced, it will also be evident that several of the pumps ard valv,-s would not be,needed, being made use of.princ;pally during tlle start-@ng and warmlip period of oleration. For bringing @the fuel cell .28 up to i'ts 65 prc@Tjer operatitig temperature, a cell heater (not, shown may @be 1 added and may be supplied with heat from an ,external source (not shown). It,will be understood that the carrying out of @this inven'cion is not limited to the use of the Bacon cell and To of-ber suitable tfuel cells @ may be used, and the temperattires and @pressures in @the system may be adjusted to the niost favorable conditions. i It will also be iinderstood thq@t the carrying out; of this invention is not limited to the use fL7ct cell. 23, but that electrodes of 'ot' icr su;table m.,,iterials may optionally be used, such@asi for example, ppri)us carbon. It will be furt@er tinderstood that while wo,'@Cr b-as L@of-n given as the working fl,,iid, the carrying out of the inverition:-is not limited to water, but may en-iploy, as a workin- fluid, other suitable liq,,iid or gaseous working :fluids_ made, up of dibsocialable compon-@nts vjhich when recombined in the- fuel cell gine. off electricity. One stich vior@ing liquid:of,this.@ciiar 4cter is hy,,drog--n r-hlo@-ide, which ,o c e - perat s, iii the fu I cell by redlction of@ cblorine qt the external 'oositive electrode or cathode, and oxidation of Ilydro.-en at-,:the exter al n.-gative electrode - @n @anode, usin.- c.lectrodes of platinum . or platinized carbon. What I
