US2879139A - Method of making hydrogen and apparatus therefor - Google Patents

Description

March 24, 1959 A. M. THOMSEN 2,879,139

METHOD oF MAKING HYDROGEN AND APPARATUS THEREFOR Filed oct'. s. 195e IN VEN TOR.

- METHOD OF MAKING HYDROGEN AND APPARATUS THEREFOR Alfred M. Thomsen, San Francisco, Calif.

Application October 3, 1956, Serial No. 613,621

2 Claims. (Cl. 23-213) This is a continuation-impart of a former -application bearing the same name and the Serial Number 231,967,

2,879,139 Patented Mar. 24, 1959 by contact with an alkaline medium, preferably a caustic ICC s alkali solution at boiling temperatures, to avoid condensation of steam.

- Obviously, there are cheaper ways of removing CO2 than the one indicated, for the sake of simplicity. Whatever means be used is immaterial so far as the operation of my process is concerned. If the secondary accumulators be large enough then virtually all steam can be condensed, removed as water, and then re-evaporated in the corresponding secondary accumulator. Actual removal of CO2v is best of all effected by the use of ammonia,

' an old application, in the event that the hydrogen be filed June 16, 1951, and now abandoned. In said former application I took a very broad view of the raw material that could be used while in the instant application I stre-ss certain features particularly evident when the raw4 `material employed be charcoal. In this manner I am able to describe and illustrate to better advantage the salient countered The composition of the gas from the blower divergence between my own technique and that now in use in the industry of making hydrogen.

l In the actual chemistry involved there is, of course, no such divergence. The reactions between carbon vand steam, whether said carbon be present as solid fuel, or 'i as carbon monoxide, or even as a hydrocarbon, is too well known in the practice of today to require any elucidation. It is assumed that the reader is already familiar with all such matters. As already stated in said former application, and now repeated, I avail myself of the reaction whereby carbon is oxidized by the oxygen resident in steam, the over-al1 effect being the formation of carbon dioxide and the liberation of the resident hydrogen in said steam as hydrogen gas. The technique employed is best elucidated by consideringthe drawing submitted herewith.

It is, of course, a well known fact thatat temperatures below 1200" F. the principal reaction between carbon and steam is that represented by thefollowing equation: 2H2O|C=CO2+2H2-3'5,000 B.t.u., but if carbon be employed in the form of coal of any vtype then residual coke reacts very slowly andthus virtually forces the abandonment of this desirable reaction for the high temperature conversion represented by the conventional practice,"namely, H2O-|-C=CO+H'2-52,850 B.t.u. Obviously, therefore, the use of charcoal as theacepted form of carbon, owing to its much greater reactivity, permits the use of the low temperature reaction.

In the drawing, therefore, let the combustion chamber be lledk with `charcoal vand, the temperaturemaintained at approximately 1200" F. by commingling sufficient 'oxygen with the entering steam to supply the deficiency in the endothermic nature of said reaction, said oxygen forming CO2 rather than CO. The products :of saidreaction then undergo the following treatment.

chamber, alternately in opposite direction, and the prodpcts of reaction commingle with said reversing gas` ow.

used in the manufacture of ammonia, but that demands coolingy to room temperature as an imperative condition.

' Returning n'ow to the drawing. I have used the expedient of representing the reversing ow by two parallel lines and directional arrows, one line being solid and the other a broken or dotted line. Starting -then at the blower and following the dotted line in the direction ofthe Varrow the first device, the scrubber, isenis virtually hydrogen with a little CO, virtually all the CO2 produced having been abstracted in the scrubber traversed by the gas before entering the blower. This Y 'right hand scrubber, therefore; has virtually no function until reversal of ilow, so the gas-passes through substantially unchanged. The amount of steam commingled with said hydrogen depends, of course, on thetemperature to which vthe gas was cooled before entering the blowen-and hence, is optional.. To avoid confusion I have shown a dot-das line connecting the two sec- 'ondary heat accumulators to indicateA that water condensed in one is re-evaporated in the other one. The function of the right hand, secondary heat accumulator is thus simply that of heating the traversing gas to the temperature suited to the catalyst which is selected from 1any conventional practice where it is desired to react steam and ,carbon monoxide for the production of hydroat the blower having been converted to CO2 in the highly veflicient catalyst contact due to previous removal of CO2.

:In the accumulator stored heat from the previous re- ',versal is now again absorbed raising the gas stream to the reaction temperature desired in thecombustion chamber, i. e., below 1200 F. On traversing this chamber,

A ,an amount of additional hydrogen and some carbon di- By means of the reversible blower, shown'at the bottom-of the ldrawing, a stream of gas is sent 'through the reaction On either side of the combustion chamber I have shown v a heat accumulator in which heat is either abstracted from or imparted to the gaseous uid every time the direction of said flow is reversed. Following the primary heat accumulator I have indicated a pair of catalyst chambers and immediately thereafter another pair of secondary heat accumulators which in turn either abstract from or impart heat to the reversing gas stream. Finally I have shown a pair of scrubbers in which the carbon dioxide formed elsewhere is removed ,oxide-is" added to the gas stream, the little C02 already present passing virtually unchanged 'through the incandescent fuel at this low temperature. The sensible heat ',in said gas is then .stored in the lefthand primary ac- ,cumulator making the temperature that desired for the catalyst. A further increment is stored in the secondary vleft-hand accumulator and the gas isv thus cooled for :the scrubber and nalremoval of CO2. I n passing through Ithe left hand catalyst ,any C O present vis largely, though not completely, oxidized to CO2 with attendant evolution of hydrogen from the steam commingled therewith. Thus is produced the gas consisting essentially of hydrogen which passes through the blower and reaches the point of origin of this description.

On reversal of ow, following now the solid line in the direction of the arrow it is obvious that the same set of circumstances will be in eiect and will produce the same result. I have indicated the hydrogen thus produced removed at the pressure side of the blower, a

solid and a dotted line being used to designate said removal. The salient featureof my process is thus seen to be a reversing ow of steam and hydrogen picking up an increment of carbon `dioxidefrom the charcoal and? parting with same at the scrubber, the one regulator of the entire operation being the amount of oxygen introduced to satisfy the heat requirement of the reactions.

Considering this use of charcoal as the carbon source for my process I have thus given a concise and completeV 4 air, such admixture being determined by gas analysis and empirical procedure.

Apparatus for this entireoperation is conventional as to design though original in operation and results. It is evident that a combustion chamber must be of refractory construction, and this same observation applies to the primary heat accumulators. The catalyst chambers are preferably also made refractory and an excellent packing is made by impregnating brick fragments with a suitable catalyst, one of the best being a soluble iron salt which in use becomes converted to the oxide. However, selection of any acceptable catalyst forms no part g of my process many excellent proprietary materials being the practice to have ve times the amount of steam pres- Timing in reversal is a function of the size of the accumulators. When the temperature at any one point exceeds an arbitrary value, empirically determined, then it is time to reverse. Similarly, if the temperature in the combustion chamber exceeds l200 F. it is time to reduce the ovygen. If the temperature drops too low it will at once show up by decreased quantity of the hydrogen produced. Again, as the amount of CO2 prof duced has an adverse .effect I deem it advisable not to permit too large a concentration before the scrubber removes it. As a limit I place a gas consisting of three times the amount of hydrogen, by weight, as carbon dioxide, this immediately before the scrubber removes it en toto. To decrease said amount obviously only means to increase the speed of the blower, thus re-cycling more pure hydrogen. Had I omitted all reference to said items it would have made no difference. Any person competent to manage such a plant will certainly know enough to supply any apparent deficit in information of which I may be guilty deeming all such material as technical knowledge possessed by any operator.

With a clear knowledge of my process as thus applied to charcoal it will be easy to understand modifications. Thus if the use of coal renders a high temperature mandatory, then the CO3 will be formed but slightly in the combustion chamber and the gas will consist essentially of hydrogen and CO, but when this passes the catalyst conversion to CO2 takes place only to an increased degree. In other words the locus for CO2 formation passes from the combustion chamber to the catalyst chamber. Every thing else remains unchanged.v Similarly, if the temperature of the combustion chamber be held at above 2200 F., at which temperature CH4 decomposes into hydrogen and carbon, then natural gas can substitute for any other type of carbon, the liberated lamp black being in turn decomposed by steam in accord with the reactions previously cited. All such minor modifications I consider as within the scope of this disclosure.

As another modication the substitution of air for oxygenbecomes a factor. In the event that ammonia be the `ultimate objective then a mixture of almost theoretical composition, the'3:1 ratio, is readily obtained. In this case nal adjustment is made by the admission of a very small amount of oxygen commingled with said available.

In the event that a brick packing impregnated with a soluble salt of some metal be selected then the mass of said packing also converts the catalyst chamber into a. type of supplementary heat accumulator, the gradient of highest efficiency of saidv catalyst moving forwards and backwards with each reversal of ow.

When they erce heat of the combustion chamber has beentempered by passage through the primary accumu lators and through the catalyst chambers then a metallic packing, such as turnings or other subdivided material with much surface, will be advantageous in the secondary accumulators. Stainless steel, Monel metal, and other resistant metals or alloys are all acceptable. Scrubber l and blower, of course, are conventional.

Having thus fully described my process, I claim:

1. The method of making hydrogen which comprises; passing a gaseous uid consisting essentially of hydrogen, nitrogen and steam, alternately in opposite directions,

through a body of carbon maintained at reaction ternperatures by the controlled admission of air, at such a rate that the carbon dioxide produced shall at no time exceed three times the weight of the resident hydrogen; storing a portion of the sensible heat in said gaseous uid as it ,fleavesthe combustion chamber in two alternate heat accumulators on each reversal of ow; removing the carbon dioxide thus produced from said iuid after said cooling through the heat accumulators; splitting off a fraction of said gaseous iluid as an accepted fraction; conveying stored heat to the remaining fraction by passage through the alternate heat accumulator and then kre-cycling said fraction to the body of carbon originally References Cited in the file of this patent, UNITED STATES PATENTS 1,223,242 Ben Apr. 17, 1917 1,505,065 West `et al. Aug. 12, 1924 1,794,232 Humphrey Feb. 24, 1931 2,502,670 Roberts et al Apr. 4, 1950 2,755,321 Hasche July 17, 1956 FOREIGN PATENTS 897,610

Germany Nov. 23, 1953

Claims (2)

1. THE METHOD OF MAKING HYDROGEN WHICH COMPRISES; PASSING A GASEOUS FLUID CONSISTING ESSENTIALLY OF HYDROGEN, NITROGEN AND STEAM, ALTERNATELY IN OPPOSITE DIRECTIONS, THROUGH A BODY OF CARBON MAINTAINED AT REACTION TEMPERATURES BY THE CONTROLLED ADMISSION OF AIR, AT SUCH A RATE THAT THE CARBON DIOXIDE PRODUCED SHALL AT NO TIME EXCEED THREE TIMES THE WEIGHT OF THE RESIDENT HYDROGEN; STORING A PORTION OF THE SENSIBLE HEAT IN SAID GASEOUS FLUID AS IT LEAVES THE COMBUSTION CHAMBER IN TWO ALTERNATE HEAT ACCUMULATORS ON EACH REVERSAL OF FLOW; REMOVING THE CARBON DIOXIDE THUS PRODUCED FROM SAID FLUID AFTER SAID COOLING THROUGH THE HEAT ACCUMULATORS; SPLITTING OFF A FRACTION OF SAID GASEOUS FLUID AS AN ACCEPTED FRACTION; CONVEYING STORED HEAT TO THE REMAINING FRACTION BY PASSAGE THROUGH THE ALTERNATE HEAT ACCUMULATOR AND THEN RE-CYCLING SAID FRACTION TO THE BODY OF CARBON ORIGINALLY CITED.

2. THE METHOD OF MAKING HYDROGEN SET FORTH IN CLAIM 1, WITH THE ADDED STEP THAT AFTER PARTIAL COOLING BY PASSAGE THROUGH A HEAT ACCUMULATOR SAID GASES BE NEXT PASSED OVER A CATALYST SUITABLE FOR PROMOTING THE REACTION BETWEEN CO AND STEAM, THE TOTAL HEAT THUS GENERATED AS WELL AS THE HEAT NOT ABSTRACTED IN THE FORMER ACCUMULATOR BEING STORED IN A SECONDARY ACCUMULATOR PRIOR TO REMOVAL OF CO2.

Images