US1878227A - Process of making carbureted water gas - Google Patents

Description

Sept. 20, 1932. D4, Y U 1,878,227

PROCESS OF MAKING CARBURETED WATER GAS Filed March 26, 1926 Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE DANIEL J. YOUNG, OF TACOMA, WASHINGTON, ASSIGNOR TO YOUNG-WHITWELL GAS PROCESS COMPANY, OF TACOMA, WASHINGTON PROCESS OF MAKING CABBURETED WATER GAS Application filed March 26, 1926. Serial No. 97,603.

The invention relates primarily to improvements in the process of making carbureted water gas and the present appl cation is a continuation in part of my appllcation, Serial No. 570,207, filed June 22, 1922 now Patent N 0. 1,751,849 granted March 25, 1930.

I have discovered that if the ordinary water gas process be modified, first by superheating steam or other gas, used in a back or down run. in some cases with the addition to the fuel bed, during said back or down run, of finely divided fuel which is capable on distillation of giving off condensible and non-condensible volatiles, a gas is produced which differs in character and composition from gas produced by any commercial process now known to me. These volatiles are passed through the fuel bed without material degradation. and the condensible portions may, if desired, be separated from the non-condensible portions in any'suitable or known manner.

An apparatus for carrying out my process may be obtained by slightly modifying an ordinary water gas-set. Such an apparatus is shown in vertical section by the accompanying drawing. In this apparatus, 1, 2 and 3 represent respectively a generator, carburetor and superheater. these being in the main the same as are now commonly used in making water gas.

The generator has the customary grate 11, an ash pit to which air for the blast is applied through a pipe as 50 and steam is supplied for making gas, as through pipe 6, these being controlled by valves 51 and 60. A gas offtake pipe 7 may also be connected at the same place. A second steam pipe 61 and controlling valve 60 may be connected with the top of the generator for special uses if desired. Likewise, gas may, if desired, be removed from the top of the generator as by pipe 91. Pipes 7 and 91 may be provided with valves as 7 0 and 92. Pipes for the admission of secondary air to the carburetor and superheater as 52 and 54 and controlled by the valves 53 and 55 are provided.

The carburetor 2 has the usual checkerbrick 23 and chamber at the bottom and the superheater 3 has its checkerbrick 33, bottom chamber 30, and stack valve 32, as is common in water gas sets. The bottom chambers 20 and of carburetor and superheater are connected by a pipe 43 in the usual way. The upper ends of generator and carburetor are connected by a flue or pipe 4, which is like the connection used in ordinary water gas sets, except that the hot valve and the down pipe 41 and its valve 42 connecting with the bottom of the generator employed in the usual water gas set are or may be omitted. The carburetor may have means, as pipe 21 through which oil may be supplied to enrich the Water gas. The oif take for gas usual in water gas practice, as 31, may be provided with valve as 34.

In modifying a water as set for carrying out my process, I provi e means for introducing steam at the end of the set furthest removed from the generator. that is, at the point where the gas is discharged in standard water gas practice. Pipe 62 controlled by valve 60 indicates such steam supply. I have also shown a steam supply pipe 64 discharging into the bottom of the carburetor. While the location of locations as that of pipe 64 nearer to the generator, may-be employed. The essential requirement in my process is the introduction of steam for use in the back run at such a point that it has become sufliciently superheated when it reaches the generator.

I also modify the standard water gas set by providing means for introducing finely divided fuel into the generator above the fuel bed. The means indicated in the drawing is to be considered only as typical and not as the only suitable means. This shows a hopper pipe 62 is that preferred, other or feed bin 8, a feed screw 80 discharging into a pipe 81 which discharges into the generator and a distributing device comprising a disk 90 carried in the generator in position to re- 5 ceive thereon the discharge fuel and revoluble with its supporting shaft 9. 'There may be provided a device with which the surface of the fuel bed may be rabbled or otherwise agitated so as to permit of the ready flow through of gases. The fuel supplying means illustrated are recognized as being of a rudimentary character and capable of further refinement of design.

In carrying out my process the first step is 1 a blasting operation designed to heat the checkerwork of the carburetor and superheater, just as in the standard water gas process. On the back run, steam or other gas is introduced at the discharge end of the superheater, or at such point between this and the generator as will sufficiently superheat the gas by the time it reaches the generator.

I have found that passage of steam or other gas through the superheater and carburetor produces a reaction upon the carbon which becomes deposited upon the walls and checkerwork, producing gaseous oxides of carbon. One beneficial result of this action is cleaning the carburetor and superheater of carbon deposits. By the time the steam and gaseous oxides of carbon reach the generator they have become very highly heated. In entering the generator the superheated steam and gaseous oxides of carbon may travel either one 85 of two paths. Preferably, since the hot valve (Double bonds are 40 and the connections thereto may thereby be eliminated, they enter the top of the generator, have mixed with them the finely divided fuel supplied through pipe 81 and pass downwardly through the fuel bed. As an alternative, however, by employing down pipe 41 and valves 40 and 42, the steam and gaseous oxides of carbon thus superheated may be caused to pass up through the fuel bed, produce water gas and leave the set by pipe 91. Fuel may be added during this operation. This fuel for best results should be finely divided. It should also contain Volatile hydrocarbons, distillable under heat to form gases.

If the added fuel be finely divided it absorbs heat from the superheated steam, wa ter gas and gaseous oxides of carbon received from the carburetor, giving ofi the volatile components as gas and depositing the remainder as coke upon the fuel bed, except that 65 portion which may combine with the excess steam to form water gas. I have found that the coke supply so produced is suflicient to supply the heat needed for superheating the steam and the water gas component of the resulting gas.

The gas which is the ultimate product of this process contains more B. t. u.s than would a gas produced from the same fuel by any other process known to the art. The reason for this is believed to be that it contains a larger percentage of the higher hydrocarbons, of which methane and benzene are types.

That is, the process is one which does not break up and degrade these higher types of hydrocarbons, but retains them in the form as originally distilled from the fuel.

It is well known that of the higher hydrocarbons, benzene (C H a single ring compound, when treated to 600 C. condenses to solid diphcnyl (C H a double ring compound eliminating hydrogen gas, and when heated to higher temperature, condenser further to a triple ring compound with elimination of more hydrogen until ultimately only solid carbon remains. These reactions may be indicated as follows Benzene L'Hl omitted from ring.)

Benzene If, however, hydrogen and, to a less extent 1 any other diluting gas, as nitrogen, steam, carbon dioxide, ctc., be present the above described decomposition or dehydrogenation is practically nullified up to a temperature of at least 800 C. These or any other gases, may be substituted for the steam in the back run.

It is also well known that, of the hydrocarbons, toluene (C H CH a single ring compound when heated to 600 C. condensed to such compounds as solid stilbene (C I-I a double ring compound, eliminating hydrogen gas. At higher temperatures (800 C.) there is further condensation, the nucleus (C H giving anthracine (G H with elimination of hydrogen gas, the latter, however, reacting further with toluene to give benzene and methane (CH At still higher temperatures the nucleus condenses further actions may e indicated as follows it it it difi'usive power and the speed with which its molecules travel. An inert or non-oxidizing ii. air it Toluene Toluene Stilbene H H H H H a a a e t H4 M... Ha o.. X y a Hd H 1130- drFHd d dd 1 f it a t e t Toluene Toluene Anthracine Hydrogen Lt Lt Hc b-om .2 H bu on.

15 ii III 1'; Toluene Hydrogen a Benzene Methane. (Double bonds are omitted from rings. Reversibility shown thus only where established.)

If then a large quantity of hydrogen is I 1 a u e present mitially, the action is checked as shown in connection-with the formation of diphenyl from benzene. The hydrogen can, however, act directly on the toluene, reducing it to benzene by combinlng wlth the CH group to form methane. Although the presence of hydrogen lessens the formation of solid molecular condensates, it promotes the decomposition of toluene by reduction to benzene, from whence the other reactions involving the latter occur. Diluting gases, other than hydrogen, would act, in some cases, to retard toluene decomposition and, in others, to lessen the degradation of benzene, after the latter has'been formed.

,In like manner, the three zylenes, ortho-, metaand para-, yield, in an atmosphere of hydrogen at 750 C. toluene and benzene by reduction and a limited amount of solid condensates. Cresol, is also reduced extensively at 750 C. in a stream of hydrogen to toluene and necessarily to benzene also.

Finally, it is also well known that all chemical equilibria require time for their complete establishment. Methane, for example, when hydrogen is present becomes increasingly unstable as the temperature rises, so that, at the temperatures prevailing in the carbonization system, the tendency of reaction is all in favor of the destruction of methane. Yet the decomposition occurs sufliciently slowly that, if means he provided for removing the methane from the zone of reaction, such decomposition is noticeably retarded. Any gas sweeping through the reaction zone will so retard degradation by removal of the decomposing gas. Hydrogen is particularly effective in this respect, not only because its action is chiefly chemical, but also because of its lightness, its

- the system and 1i i p Hydrogen gas, as nitrogen, is also effective by reason of its distilling action for it can physically sweep out the forming and reacting gases rom the pores of the fuel, and so remove them from the zone of degradation. Partieularly is this true if the fuel be in a state of fine division.

\Vhere combustible gas is desired, the nitrogen may be supplied by admitting air into passing it over the heated checkerbrick and through the fuel bed of the generator. The oxygen in the air will be largely converted into gaseous oxides of carbon by reaction With the carbon upon the checkerbrick, and these gases, together with the nitrogen passing through the fuel bed of the generator, sweep out and carry with them the forming and reacting gases contained in the pores of the fuel in the manner described above. Where fuel distillation is the primary object, nitrogen substantially free from oxygen may be employed instead of air.

\Vith proper regulation of conditions large quantities of ammonia can be recovered by means of this process as where steam and a nitrogen containing gas are admitted together during the backrun In summation, therefore, it may be said the dehydrogenation with resulting solid condensates and degradation of the nucleus at high temperatures is noticeably retarded, in the presence of any gas stream, the action being chemical or physical or both and particularly effective when fine division of the. fuel permits of intimate contact between the gas stream and solid fuel particles.

In my process, therefore, by reason of the volumes of steam, water gas and other constituents of the gas stream which is flowing through the zone of distillation and through the fuel bed, degradation of higher hydrocarbons in the distillation gases is retarded. Such retardation of de radation is due, in part, to the presence 0 hydrogen or other gases, not only in the distillation gases themselves but also in the forming of water gas. Degradation of such higher hydrocarbons is further retarded because the distillation gases are quickly removed from the pores of the finely divided fuel and from the high temperature zone thereby materially shortening the time during which they are exposed to the breaking down tendency of such high temperatures. In consequence, the gas produced has a higher percentage of the higher hydrocarbons than the gases of analogous character heretofore commercially produced. The condensable portions of such gas may if desired, be separated out inany suitable manner.

Asthese gases pass through the fuel bed the excess steam contained therein combines with the carbon to form water gas. There may also be interactionbetween the gases distilled from the raw fuel and the carbon of the fuel bed. There is less free hydrogen I as referring to the shells 2 and 3, the terms primary and secondary heat interchangers may be used to refer to the same elements. Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An improvement in the usual two-cycle I process of making carbureted water gas, carriedout in aplant comprising a single generator having a bed of so 1d fuel, a single carburetor and a single superheater, one cycle consisting in air blasting the fuel bed of the generator and storing the resulting heat successively in the carburetor and superheater, and. the other cycle consisting in making a forward steam run through the fuel bed in the generator in an upward direction, then passing the generated water gas through the carburetor and superheater, simultaneously adding oil to the carburetor and withdrawing the resultantcarbureted water gas directly from the superheater; the improvement which consists in introducing nitrogen into the plant, superheating the nitrogen and passing it in a downward direction through the fuel bed of the generator, whereby a combustible gas is produced, and withdrawing the resulting combustible gas directly from the generator.

2. An improvement in the usual two-cycle process of making carbureted water gas, carried out in a plant comprising a single generator-having a bed of solid fuel, a single carburetor and a single superheater, one cycle consisting in air blasting the fuel bed of the generator and storing the resulting heat successively in the carburetor and superheater,

'and the other cycle consisting in making a forward steam run through the fuel bed in the generator in an upward direction, then passing the generated water gas through the carburetor and superheater, simultaneously adding oil to the carburetor and withdrawing the resultant carbureted water gas directly from the superheater; the improvement which comprises introducing a gas having a large nitrogen content into the plant, superheatmg'the nitrogen and passing it through the fuel bed of the generator,whereby combustible gas is pro uced, and withdrawing the resulting combustible gas directly from the generator.

3. An improvement in the manufacture of carbureted water gas, carried out in a plant comprising a single generator having a bed of solid incandescent fuel, a single carburetor and a single superheater; which improvement \comprises the step of introducing nitgrogen into the plant, superheating the nitrogen withinthe plant, mingling said superheated nitrogen with finely divided fuel containing volatiles, extracting said volatiles, passing the nitrogen and volatiles through the incandescent fuel bed of the generator, and withdrawing the resulting gaseous product directly from the generator.

4. An improvement in the manufacture of carbureted water gas, carried out in a plant comprising a single generator having a bed of solid incandescent fuel, a'single carburetor and a single superheater; which improvement comprises the step of introducing a gas having a large nitrogen content into the 1 plant,-superheating the gas within the plant, mingling said superheated gas with finely divided fuel containing volatiles, extracting said volatiles, passing the gasand volatiles through the incandescent fuel bed of the generator, and withdrawing the resulting gaseous product directly from the generator.

5. An improvement in the manufacture of carbureted water gas, carried out in a plant comprising a single generhtor having a bed of solid incandescent fuel, a single carburetor and a single superheater; which improvement comprises the step of introducing agas having a large nitrogen content into the plant, superheating the gas and passing it throu h the fuel bed of the generator, whereby co bustible gas is produced, and withdrawing the resulting combustible gas directly from the generator.

In testimony whereof I afiix my signature.

DANIEL J. YOUNG.

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