US1624644A - Process of making combustible gas - Google Patents

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w. D. wlLcox PROCESS OF MAKING COMBUSTIBLE GAS April 12,1927. 1,624,644

' Filed April 1. 1921 2 Sheets-Sheet 1 4 4 1,624,644 APT!l 1927' w. o. WILCOX PROCESS MAKING COMBUSTIBLE GAS Filed April 1.. 1921 2 Sheets-Sheet 2 Patented Apr. 12, 1927.

UNITED STATES PATENT OFFICE.

WILLIAM D. WILGOX, OI IDAHd FALLS, IDAHO.

PROCESS OF MAKING COMBUSTIBLE GAS.

Application filed. April 1, j

in one continuous operation, producing a combined coal and water as, with the least possible loss of heat in the operation, and consequently the largest possible output of gas from a given weight of fuel. There are in existingprocesses substantial losses of heat which it seems possible to avoid. In driving the volatile gases from coal by means of'heat passed by conduction through walls of substantial thiclmess and relatively poor conductivity and from the innersur face of these walls through coal which is itself a poor conductor, it is necessary. to generate bythe burning of bench fuel, a much greater quantity of heat than is actually realized in changing the volatiles of the coal from the solid to the gaseous state. Not more than a small proportion ofthe total heat isutilized in ordinary practice.

Where the coke is used to produce water gas in a detached generator, the sensible heat imparted to it in the carbonizing process is removed by quenching and lost. In the production of water gas it is necessary to bring the cold fuel by air blasting to a temperature substantially in excess of the minimum temperature at which the oxygen released by the decomposition of the water molecule H O will unit with the adjacent carbon predominately as carbon monoxide (CO) rather than as carbon dioxide (CO From this necessity, it follows that whatever may be done by increasing the blast pressure or reducing the height ofthe fuel bed, there is during the latter portion of the air blast a loss of fuel value not only as sensible heat in the escaping blast gases, but by the presence in the blast gases of a large proportion of the carbon monoxide. This requiresthe burning of a greater weight of fuel and the production of a eater quantity of heat than is utilized to ecompo'se the steam. Y

I am aware-that apparatus has been in- 1921. Serial No. 457,811.

vented in which regenerator chambers filled with checker brick are heated to a high tem perature by the sensible heat of the escaping blast gases and by the burning therein ofthe carbon monoxide-content, and through which the water gas and steam are made to pass during an intermediate period in the process of generation so that much of thish-eat is 4 made useful in increasing the make of water gas. A considerable gain in thermal efficiency has been secured by the use of this ap:

paratus, but it ,has certain disadvantages when the fuel used is bituminouscoal which it 1s the purpose of my invention to eliminate.

In this apparatus blasting-is upward, the

air being admitted 'under pressure below the grate of the generator. The hot products of combustion pass upward through the layer of green or freshly charged fuel upon the upper surface of the fuel body, and carry forward into the regenerator to be destructively consumed therein during the blasting period a large proportion of the hydrocar bon volatiles of the coal. During the run period, steam admitted below the grate of one generator passes upward, through the regenerators, into the upper portion of a second generator and then downward through the bodyof incandescent fuel, the resulting water gas being withdrawn quite hot from a level a little above the grate in the second generator.

It is claimed as a merit of the process attained in this apparatus that the hydrocarbon gases and -tarry vapors carried forward by the current of water gas are, by.

contact with the hot carbon in the lower portion of the second generator, broken up into hydrogen and carbon monoxide so that the gas can be used with very little effort toward the removal of the tan But where an enrichedgas containing a greater number of heat units in a given volume is desired this is not an advantage, but rather the reverse. The apparatus which I have designed is somewhat similar to that just described, consisting of twin generators, discharging into corresponding regenerators which are cross connected at the top, but with such changes in the arrangement of parts, and in the method of operation, as to produce a very difierent product. The air is admitted not below the grates, but at a level intermediate. betweenv the upper surface of the fuel body and the grate The air does notpass upward, but downward. The passages conducting the blast gases from the generators into the regenerators are not above the upper surface of the fuel but just above the grates. The conserved gases, instead of passing downward through a body of highly heated coke to an outlet just above the grate arewithdrawn through an outlet above the level of "the fresh coal. Only a very small proportion of the rich hydrocarbons in the coal given off during the blasting are decomposed by contact with hot carbon during the generation period. In. order to minimize the destruction of the rich coal gases given off from the material in the upper levels of the generator chamber during the air blasting period, as a result of precedent heating, the conserved gas outlets may be left partly open; the openings being controlled by the observation of pressure gauges indicating the pressure at the air inlet and gas outlets, so that the pressure of gas generation will balance the blast pressure and permit no'air to pass upward and little or no coal gas to pass downward below the level at which air is admitted.

The hydrocarbons are distilled off by the upward passage of the water gas during the steam run period, hence are littledecomposed and the sensible heat of the hot water gas which as a usual practice is removed by cooling, is thus made useful, taking the place of and accomplishing the work done by a much larger quantity of heat generated by the burning of bench fuel in the usually employed method of carbonizing coal. This sensible heat acts with greater efficiency because the gas which imparts it to the coal passes upward in direct contact with the coal in a fairly uniform Volume throughout the horizontal cross section of the coal body.

The process and the design of the apparatus can be better understood by reference to the accompanying drawings. Figure 1 shows a vertical elevation viewed from one end. Figure 2 is a vertical cross section of the apparatus. Figure 3 is a horizontal cross section taken at XX as shown by Figure 2 but not showing the fuel and checker work. A and A are gas generators. These are filled nearly to the top with bituminous coal intr0- duced from time to time through charging doors, J and J During the blasting period, air is admitted through air inlets C and C and smaller air inlets 1 and 2 admit-.

ting to enerators A and A respectively. At this time gas outlets D and D are closed. Waste or blast gas outlet E is open. The combustion products pass downward and through. passages L and L into the regenerator chambers B and B where they are fully' burned by air entering at H and H. A limited quantity of air entering during this period below the grates G and G at H and H secures a complete combustion of the generator fuel to ash. When the desired temperature has been attained by blasting,

the air is shut off. Steam is then admitted,

at both C and C through M and M? to purge the apparatus. One steam inlet is then closed. In one period this is M M being open, E is closed, gas outlet 1) is opened, steam entering at C under the'pressure supplied by its generation in a boiler passes down through the body of fuel in A through L ,up B across, down B though L into A up A and through the body of fresh or uncarbonated fuel above the level of C in A to which it imparts a large portion of its Doors F and F are provided to permit the cleaning of the grates and removal of dust which may drop out of the blast gases in the regenerators. K and K are manholes which may be periodically opened to permit a replacement of burned out checker brick.

The process may be carried out in apparatus of somewhat different design, as, for example, the generators maybe detached and of the more usual cylindrical form dischargingthrough pipes into corresponding detached regenerators. It is not my purpose to restrict myself to a particular design of apparatus in carrying out the process.

I claim:

The herein described process of generating coal and Water gas by admitting air for blasting at an intermediate level to a body of coal contained in each of two generators, and thereby heating the fuel to incandesence, passing the blast gases downwardly and into corresponding regenerators, adding additional air for the combustion of the blast gases therein, alternately thereafter admitting steam to one of the two generators at the same level at which air was previously admitted, passing the steam downwardly through the incandescent fuel to form water gas, passing the water'gas into and up the adjoining regenerator, across, and down the second regenerator and thereby superheating the water gas, passing the superheated water gas into the second regenerator, and then upwardly through a body of fuel having a layer of uncarb'onized coal to a gas .outlet above the coal, whereby mixed coal and water gas is produced.

WILLIAM n. wi co x.

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