US1505065A - Process for the production of hydrogen or gases rich in hydrogen - Google Patents

Description

Aug. 12. 1924. 1,505,065

J. H. WEST ET AL PROCESS FOR THE PRODUCTION OF HYDROGEN 0R GASES RICH IN HYDROGEDM Filed 00b5, 1922 Patented Auga 12, 1924.

" UNITEDSTATES PATENT OFFICE.

' J 0311' HENRY WEST, OF BAYSWATER, AND ARTHUR JAQUES, OE WATERLOO, ENG-LAND.

PROCESS FOR THE PRODUCTION OF HYDROGEN 0R GASES RICH IN HYDROGEN.

Application filed October 5, 1922. Serial No. 592,496.

To all whom it may concern:

Be it known that we, JoHN HENRY WEST and ARTHUR JA Uns, both subjects of the King of Great Britain, residing, respectively, at Bayswater, in the county of London, England, and Waterloo, in the county of Lancaster, England, have invented certain new and useful Improvements in a Process for the Production of Hydrogen or Gases Rich in Hydrogen, of which the following is a specification.

This invention relates to the manufacture of hydrogen, or gases rich in hydrogen, by a process of completely gasifying coal or similar fuel of a bituminous type, that is containing a relatively high percentage of volatile matter, as opposed to fuels of the type of anthracite and coke which contain a relatively low percentage of volatile matter.

combined process of carbonization in retorts followed by treatment of the carbonized fuel with steam in another part of the same apparatus for the production of'water gas, has hitherto been carried out so as to produce a gas of a certain standard of calorific value, as much gas being obtained per ton of coal as is compatible with this requirement. With this object in view it has therefore been necessary to keep the amount of inert a'ses present low, and this has been the case-with regard to the car ondioxide,

which is more under control than the nitrogen unless, indeed, oxygen were to be used instead of air for the combustion of that part of the fuel charge which is directly articu arly.

method of working is the production of much greater quantities of hydrogen than have hitherto been obtained per ton of coal gasified, without reference to the calorific value of the gas produced.

According to the present invention the process for the production of hydrogen consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction throu h the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the produced portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, and regulating the uantities of steam and air employed and t e points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from theaforesaid zone through the fuel bed in the producer down to "a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn off, whereby the two main reactions which occur, namely the water gas reaction and the direct combustion of a portion of the carbonized fuel to oxides of carbon are carried out in such manner as to favor in their final result the oxidation of the carbon to carbon dioxide instead of to carbon monoxide so that the gases obtained contain a relatively high proportion of carbon dioxide. It isto be understood in carrying out the present process that instead of treating the carbonized fuel in the producer chamber with steam and air mixtures can be employed in which the air is enriched with oxygen so that steam, air, and oxygen can be employed if desired in place of steam and air alone. It is to be understood therefore that throughout the present specification and claims the reference to treatment of the carbonized fuel with steam and air is used in a broad enough sense to include such treatment being carried out with steam, air, and oxygen.

Under the conditions specified for the present invention combustion of that part of the fuel charge which has to be burnt to supply heat for the water gas reaction is carried largely to carbon dioxide, whereby a saving in fuel is effected so that a larger quantity of it is available for the water gas reaction, and the water gas reaction that is principally aimed at as a final result (and without considering intermediate stages) in substitution for that in which carbon monoxide is produced is the reaction to carbon dioxide according to the equation whereby the amount of heat required per pound of carbon gasified is only about 65 per cent of that required in the case of the reaction zones of high temperature occur large quan titles of carbon monoxide will be produced, this carbon monoxide being subsequently transformed into carbon dioxide according to the reversible reaction This reaction tends to take place more from left to right as the temperature decreases and the production of carbon dioxide at a given temperature is also favored by the presence of an excess of steam above that which actually reacts with the carbon.

It is therefore necessary in carrying out this process (a) to provide a certain excess of steam, the total steam used in that part of the apparatus functioning as the producer amounting preferably to between 3 and 5 lbs. r pound or carbon gasified, as compare with about 0.7 lbs. steam generally used in ordinary producers, or 1.7 lb. used in producers with ammonia recovery; and (b) to keep the temperature in the region near the exit point of the gas comparatively low, preferably between about 600 to 750 C. The velocity of the reaction decreases considerably with the temperature, falling to a low value even at 500 C.- The temperature at which this stage of the process is carried out in accordance with the present invention is determined by the two considera per cent ash the proportion of carbon dioxide in the water gas was found always to be high and up to 29 per cent over a certain range of temperature, whereas with almost pure carbon the carbon dioxide did not exceed 8.6 per cent. We therefore prefer, in the operation of the present process to use fuels in which the ash content is high rather than low, say from 8 per cent to 15 per cent or over, and not as low as 4.- per cent or 5 per cent, or to add to the fuel employed some catalyst material which exerts a favorable influence in promoting the formation of carbon dioxide rather than carbon monoxide during the water-gas reaction.

In order that the invention may be clearly understood and readily carried into effect the same will now be described with. reference to the accompanying -drawing which shows a vertical sectional view of one form of apparatus suitable for carrying out the process.

The apparatus comprises an upper retort portion A, into which the coal is fed at the top through a suitable valve of cone or sliding type. This retort may be of truncated conical shape. The coal passes slowly downwards through the retort, whilst being'heated by the hot gases travelling up through the acket B of the apparatus, and is thereby carbonized, the temperature in the retort rising gradually as the fuel travels on from the inlet to the top of the producer chamber C. The carbonized coal descends into the producer Q where a mixture of steam with air, or oxygen. or air admixed with oxygen is blown into it through the pipes D, D, D, and the ports E, E. E. The quantities of thesteam and air or other gases employed and the points at which they are admitted to the producer are regulated so that the reactions take place in the manner required for the production of a gas (consisting prin cipally of hydrogen, carbon dioxide, carbon monoxide and nitrogen) containing a relatively high proportion of carbon dioxide, and in compliance with the conditions previously referred to. Further the proportion of air or other gases employed to steam is so regulated as to maintain a zone of maximum temperature, say 1000 C. to 1200 C. at about the level F, and a gradually fall ing temperature down through the fuel bed tion of the fuel, say 600 C. to 750 in the producer so that the temperature just above the grate G is as low as is consistent with obtaining reasonably complete asii ilpge gases pass downwards through the grate G, and then outwards through the ports H, H, into an annular flue J surrounding the producer. Here the gases are heated somewhat by heat transmitted through the walls of the producer, and they then pass into the chequerwork jacket B, where they serve to heat and carbonize the coal in the retort.

In the ordinary systems of complete gasification the usual practice is to draw off the tarry vapors produced during the car bonization stage and extract from them the tar, benzol, and other by-products. In the case however of the present invention these vapors are passed through the hottest zone of the apparatus so asto crack them, there-' by at the same time freeing the hydrogen contained in the hydrocarbons, and rendering available for the subsequent water-gas reaction the carbon present in the h drocarbons, whilst any portions of the a orementioned vapors which are not so cracked will be burnt to'assist in providing the supply of heatrequired for carrying out the process. If desired there may be blown into the upper retort A of the apparatus a cer tain amount of steam which will react with the carbon liberated by cracking the hydrocarbons to form water-gas.

In order to secure this result the gas is caused to travel downwards through the fuel bed in the lower producer chamber C and the air supply is regulated so that the zone of highest temperature occurs at or near the top of the fuel bed, thus causing the hydrocarbons to be cracked immediately on leaving the retort, while the carbon monoxide produced in this zone of high temperature reacts with the steam in the lower cooler part of the bed roducing hydrogen and carbon dioxide. is already mentioned the gases pass from the bottom of the fuel bed through the ports H, H, into an annular jacket or chamber B surrounding the retort. A certain amount of excess steam will pass away with the gases from the bottom of the producer, and this may be augmented by further steam admitted through the pipes K, K, so that the reaction CO 2 2 i' z will take place in the chequerwork, where the surface of firebrick will ass st the reaction catalytically, while, in order to cause this reaction to take place more completely, the upper part of the jacket L may contain some catalyst material such as coke ashes. The catalyst material may conveniently be supported on' trays M, M, of cast iron or other suitable material and steam may be admitted at several points through pipes N, N, so that advantage is taken of the greater speed'of the reaction at higher temperatures by converting a large proportion of the carbon monoxlde to carbon dioxide at temperatures between say 700 C. and 550 C., and leaving but a small amount to be converted at lower temperatures, where the equilibrium oint is more favorable to the formation 0 CO and hydrogen, but where the reaction velocity is comp-aratively very slow. Steam is added through the pipes N, in such a way as to cause a fall of temperature towards the top of the catalyst jacket, which may be maintained, for example between 400 C. and 550 C. The heat of the exothermic reaction.

is absorbed partly by the steam and partly by transmission through the walls of the retort. The gases leave the apparatus by the pipe 0. If desired the catalyst material may be contained in an apparatus sep- -main constituents only being given Percent. 00 12 C0 18 H, 47 N 23 This gas, after removal of carbon dioxide would contain 57 per cent of hydrogen, whilst the power gas remaining after removal of hydrogen by, for example, the liquefaction process would contain approximately:

Per cent. CO 30 H, 14 N 56 In the case of the example above given, the heat of combustion of the carbon monoxide and hydrogen in the power gas is just about sufiicient to produce the whole of the steam required for the water-gas reaction, including the necessary excess. It will be seen therefore that as compared with the gases obtained by the methods heretofore employed the gas produced in accordance with this invention is of but low calorific power, but on the other hand the quantity of hydrogen obtained from a ton of coal is about dou le that produced by existing methods of complete .gasification,

In other cases where the necessary steam required in the operation of the process is provided from a separate boiler plant, or partly from a separate boiler plant and partly from water-heat boilers or heat interchangers heated by the gases and excess steam issuing from the gasification plant, the conversion of carbon monoxide and steam into carbon dioxide and hydrogen 2 may be carried considerably further, until,

for example, only a few per cent of carbon monoxide remain in the gas. In such cases the total amount of steam employed must be proportionately increased.

From the gaseous products obtained by the process'in accordance with the present invention the hydrogen may be separated by any of the known methods, as for example by liquefying all the gases present other than hydrogen, the carbon dioxide having been previously removed in a convenient manner, for example, by extraction with water or alkalis or water and alkalis and preferably under pressure. As before indicated the gases remaining after removal of carbon dioxide and hydrogen may be burnt under boilers for the production of the necessary steam. In certain cases however as above indicated it may be preferred to carry as far'as possible the conversion of carbon monoxide into carbon dioxide according to the equation and then remove the few remaining per cent of carbon monoxide by converting it into methane for example by the aid of a suitable catalyst. I

The present method of manufacture of hydrogen is particularly suitable for use in connection with the production of synthetic ammonia, and further if the ammonia is to be converted into ammonium chloride by the modified ammonia soda process that is employed for this purpose, an abundant supply of carbon dioxide is available. By means of the present process the requisite nitrogen for the synthesis of ammonia is also readily obtained, as, if the flue gases from the boilers under which the power gas is burnt are treated for the removal of steam and carbon dioxide, practically pure nitrogen will result, particularly if the' minimum possible quantity of air be used for. the combustion.

' What we claim and desire to secure by Letters Patent of the United States is 1. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber, and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly-from the retort to the producer, the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, and regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the tempera ture decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn off.

2. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the in let of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the ,zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, the quantity of steam employed being in considerable excess above that actually required to react with the carbon, and regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn off.

3. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising van upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the

series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the prod-ucer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, the quantity of steam employed amounting to between 3 and 5 pounds per pound of carbon gasified, and regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber s that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the {producer chamber where the gases are drawn off.

l. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the pro ducer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, and regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so as to form a zone of highest temperature in the neighborhood of 1000 C. to 1200 C.

at the top of the fuel bed in the producer chamber and produce a gradual decrease in temperature down to a temperature of comparatively low value in the neighborhood of 600 C. to 750 C. at the bottom of the poduccr chamber where the gases are drawn 0 5. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the said retort being surrounded with an ex ternal jacket charged with a suitable catalyst material for assisting the catalytic conversion to carbon dioxide of the carbon monoxide contained in the hot gases obtained as a result of the process which are passed through the said external jacket, and the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed the producer chamber to simultaneous treatment with steam and air, and regulatin the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn oil". I

6. A process for the production of gases rich in hydro en by the complete gaslfication of coal, w ich consists in subjecting the coal to carbonization in a retort chamber, passing the hot gases obtained as a result of the process together with an additional quantity of steam to assist the reaction of the carbon monoxide in the gases to carbon dioxide through an external jacket surrounding the retort chamber, the said external jacket being charged with a suitable catalyst material for assisting the catalytic con-i version of the carbon monoxide in the ases to carbon dioxide, and the said retort 0 amber being arranged in open communication with a lower producer chamber so as to allow the carbonized fuel to fall directly from the retort to the producer, and the series of steps of completely gasifying the coal consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, and regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn ofi.

7. A process for the roduction of gases rich in hydrogen whic consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow-the carbonized coal to fall directly from the retort to the producer, the series of steps of the rocess consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part'of the fuel bed situated at the bottom of theretort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the pro- 'ducer chamber to simultaneous treatment with steam and air, regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gasesare drawn off, removing the. carbon dioxide firom the mixture of gases obtained as :1

result of the process and separating the hydrogen from the remaining constituents of the gases.

8. A process for the production of gases rich in'hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the series of steps of the process consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer cham'ber, cracking the vapors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so that the zone of highest temperature is located at the top of the producer chamber and the temperature decreases gradually from the aforesaid zone through the fuel bed in the producer down to a temperature of comparatively low value at the bottom of the producer chamber where the gases are drawn ofii', removing the carbon dioxide from the mixture of gases obtained as a result of the process and separating the hydrogen by a liquefaction process from the remaining constituents of the gases.

9. A process for the production of gases rich in hydrogen which consists in completely gasifying coal in an apparatus comprising an upper retort chamber and a lower producer chamber arranged in open communication with the retort chamber so as to allow the carbonized coal to fall directly from the retort to the producer, the said retort chamber being surrounded by an external jacket through which are passed the hot gases obtained as a result of the process and drawn off at or near the bottom of the producer chamber, and the series of steps in the process consisting in carbonizing the coal by subjecting it to temperatures which increase gradually as the coal passes from the inlet of the retort chamber to the top of the producer chamber, cracking the vaors and gases produced during the carbonization of the coal in the retort chamber by passing them in a downward direction through the zone of highest temperature located in the neighborhood of that part of the fuel bed situated at the bottom of the retort portion and the top of the producer portion of the apparatus, subjecting the carbonized fuel in the producer chamber to simultaneous treatment with steam and air, the quality of steam employed amounting to between 3 and 5 pounds per pound of carbon gasified, regulating the quantities of steam and air employed and the points at which the said steam and air are admitted into the producer chamber so as to form a zone of highest temperature in the neighborhood of 1000 C. to 1200 C. at the top of the fuel bed in the producer and roduce a gradual decrease in temperature own to a temperature of comparatively low value in the neighborhood of 600 C. to 750 C. at the bottom of the producer chamber where the gases are drawn ofi', removing the carbon dioxide-from the mixture of gases obtained as a result of the process and separating the hydrogen by means of a liquefaction process from the remaining constituents of the gases.

JOHN HENRY WEST.

ARTHUR JAQUES.

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