US2516141A - Apparatus and method for gasifying carbonaceous material - Google Patents

Description

.Ey 1950 L. L. NEWMAN EIAL 2,516,141

APPARATUS AND METHOD FOR GASIFYING CARBONACEOUS MATERIAL Filed July 1, 1949 Gases dust (co ri -+00 Corundum brick Chrome brick 9 Armstrong A-26 ,g brick or equal A A Pul wleri'zed Pulverlizetli A coo me v coo m et 1 :2 3,500 "P. 5 0 maximum Inlet Optical pyrometers or suitable measuring instruments located at various elevations through combustion zone.

[ Steam CO Cool A inlet 2,500F.

Oxygen 11 B Oxygen or 2 x v A v COOI Inlet 2,5oo|=.

E Seciion XX INVENTORS Y= Nozzle (cool +0 size to Fig 2 L L. NE 71 secure a greater velocity 06k 7.' 00 of entering material than BY the coal +0 flame propagation.

Patented July 25, 1950 APPARATUS AND METHOD FOR GASIFYING CARBONACEOUS MATERIAL Louis L. Newman, Washington, D. 0., and Jack T. Donovan, Louisiana, Mo., assignors to the United States of America as represented by the Secretary of the Interior Application July 1, 1949, Serial No. 102,652

6 Claims. (Cl. 48-203) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention herein described and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to an apparatus and likewise method for gasifying finely granular or divided solid carbonaceous material, such as anthracite, bituminous or sub-bituminous coal or lignite coal, peat or coke thereof for the production of very efiicient heating or lighting gas employing both an oxygen-bearing gas but a deiiciency thereof and superheated steam.

It has been proposed by Van Nuys in U. 8. Patent No. 2,177,379 to avoid the formation of CO2, which reduces the calorific value of the product, by the utilization of the following conditions: employment of an excess of the fuel over that which will react with the oxygen, maintenance of the reaction continuously at the highest attainable temperature whereby CO2 is not produced, and the completion of the reaction by the introduction of steam whereby it mingles with the gases and the highly heated unconsumed carbon. As the patentee has stated: At the temperature resulting from the initial combustion, the steam reacts with the carbon of the fuel in accordance with the reaction with the resultant production of carbon monoxide and hydrogen. These products mingle with the carbon monoxide CO from the initial reaction. Theoperation is continuous. The apparatus for carrying out the method disclosed by Van Nuys involves conduits for injecting oxygen and conduits for injecting the finely divided fuel positioned at opposite sides of the combustion chamber, with steam conduits positioned below the spaced oxygen conduit and on the same side. Deflectors of ceramic material are positioned on a vertical wall so that the steam impinges upon them and is caused to mingle with the gaseous products of the initial combustion and the highly heated surplus fuel which is not burned with oxygen.

Totzek in U. S. Patent No. 2,344,007 has an apparatus for a distinctly stage type of reaction to secure a gas of high CO content from coal using air and superheated steam which is characterized by a horizontal cylinder connected at the upper part on one side to a combustion chamber, for the subdivided coal, the horizontal cylinder having steam inlets which are arranged tangentially to the cylinder wall.

There are features of the present invention, not to be found however in these prior developments, the advantages of the existence of which will be explained.

One of the major features of the gasifier is series of nozzles for jetting the coal with oxygen into the reaction zone, radially disposed so that the jets impinge upon each other thereby producing violent turbulence and intimate mixing of the gases and finely divided coal. Furthermore by this arrangement the rapidly moving jets are thus prevented from striking the opposite wall, which would cause serious erosion to the refractory wall. Another feature is the inlet nozzles for introducing superheated steam and/or carbon dioxide at a point of lower elevation than that of the coal-oxygen inlets. The'steam inletnozzles are arranged tangentially along the circumference. bon dioxide which is ejected tangentially swirls around the inside periphery. and because the outlet for the resulting heating gases formed in the reactions is located at the top of the apparatus, they rise vertically along the inside wall of the reaction chamber. The admission of steam which is slightlybelow the level of admission of-oxygen and coal serves to pick up and return to the combustion zone carbonaceous material which drops out of the stream. Because the steam is superheated, as at 2500 F., the unreacted highly heated particles of coal are capable of reacting with the steam as has been explained in reference to the Van Nuys patent to give carbon monoxide and hydrogen. Another function of the swirling, rising steam or carbon dioxide is the protection of the refractory wall from the high temperature developed at the center of impingement of the opposing coal-oxygen jets.

Above the zone of admissions and major reactions, which has been explained, there is a conical zone and above that another larger and preferably cylindrical zone. The purpose of these zones is to provide additional reaction space with an enlarged cross section in which the velocities of flow would be reduced sufficiently to permit some of the entrained fuel to drop back into the reaction zone. The gases of high calorific value but still carrying minute particles leave the large cylindrical zone through an off-take pipe which preferably is steeply sloping to prevent the settling ofrefuse along the bottom of the offtake pipe.

This immediately preceding paragraph explains features which are associated with the preferred embodiment. The essential features of this con- The steam or highly heated car-.

\ ratus.

Figure 2 represents a section along the line 11-3 of Figure 1.

After the generator (Figure 1) has been brought up to a temperature high enough to insure immediate ignition, pulverized coal admitted at conduits A and oxygen admitted at conduits B are mixed in nozzles C. The amount of oxygen is not sufllcient for complete combustion of the coal. shown) and designed to secure a velocity of the mixture which exceeds the velocity of flame propagation of the coal and oxygen. The nozzles C are radially disposed, as can be seen from Figure 2, so that the jets of burning oxygen and coal emanating from them impinge at the center of the circle around which the nozzles are disposed. By this structural arrangement corrosion of the refactory lining of the reactor is prevented, since the streams do not reach the opposite side of the circle. The impingement causes violent mixing and combustion of the oxygen and coal at flame temperatures which may reach or exceed 4000 F. At these temperatures and with the above designated control of coalzoxygen ratio the products of combustion are principally carbon monoxide. As a result of the impingement and of gravitation, some ash and unburned fuel which may or may not have agglomerated tend to drop out of the stream toward water-cooled hopper D. steam is admitted through tangential nozzles E at a level below the level of the oxygen and coal nozzles C. The admission of steam below the level of the oxygen and coal serves to pick up and return to the combustion zone any material which drops out of the stream. The flow of the steam in a vertical manner along the circumference also protects the refractory wall from the high temperatures developed at center of impingement. When the steam reaches the level of combustion of the oxygen and carbon it reacts with the unconsumed' hot carbon to produce substantially carbon monoxide and hydrogen.

The zone of admission, F, of oxygen, coal and steam is cylindrical. Immediately above this zone is an expanding conical zone G, superimposed by another cylindrical zone H. The purpose of these zones is to provide additional reaction space with an enlarged cross section in which the velocities of flow would be reduced sufflciently to permit some of the entrained fuel to drop back into the reaction zone. The gases leave zone H through an oiftake pipe J which preferably is steeply sloping to prevent the settling of refuse along the bottom of the pipe. Immediately below reaction zone F is a narrowing conical zone K beneath which is attached ash receiver D referred to supra. Ash receiver D is preferably water cooled by the water bath L provided with waterinlet pipe L and outlet pipe L". The ash receiver is provided with a suitable rlnnr mvahm u Nozzles C may be water cooled (not for the discharge of the ash. In place of a door or valve the base of the ash receiver M, when the operation is at pressures which are close to at mospheric, may discharge directly into a sluiceway through a pipe which is dipped sufficiently below the water level to prevent the gas pressure from blowing the seal (not shown). Although the external steel jacket N surrounding the refractories is shown as a combination of cylinders, cones, etc., it is recognized that for operation at high pressures, for example 30 atmospheres, the external jacket, may be entirely composed of a combination of cylinders and hemispheres; and it may be wholly or partly water jacketed in any manner which may be devised by persons Skilled in the art. Similarly, the manner of and means utilized for pumping and mixing the oxygen and coal or the steam is left to the option of persons skilled in the art. The innermost lining of zones H, G, F and K may be made of corundum brick, which is surrounded by a layer of chrome brick which in turn is surrounded by Armstrong A-26 brick or the equal.

The hot gases and dust leaving the generator through ofitake J may be handled in a manner suitable for the end use of these gases. Generally the gases and dust are passed through a cyclone-type dust remover capable of operating at high temperatures. The gases, free of the major portion of dust leaving the dust remover, then pass through a waste heat boiler capable of supplying all of the steam required by the generator. After the waste heat flow through water scrubbers, precipitators, puriflers, CO converters, etc. when operating close to atmospheric pressure exhausters may be required to draw the gases through the scrubbers and precipitators.

Our apparatus is suitable for the gasiflcation of coal under pressure because it lends itself to the use of cylinders and hemispherical heads for the external jacket. The advantages of operating under pressure when the product gas is to be used under pressure consist of smaller generating and gas cleaning and conversion apparatus, a greater concentration of the gaseous molecules around the solid fuel particles with consequently improved reaction rates. A still greater advantage gained by operating at high pressure is in the saving of pumping costs. Instead of pumping the entire volume of the product gas from atmospheric pressure up to, say, 30 atmospheres which may be the operating pressure required for a given gas synthesis o eration, our apparatus would only require the oxygen to be compressed. The steam would be available at operating pressure from suitably provided boilers, and the coal, being in solid form, would only require handling under pressure. Since the volume of oxygen is normally about 25 percent of the volume of the product gas, pumping costs are reduced by percent.

The apparatus described above is designed to operate at reaction zone temperatures of 3500- 5000 F., and for off-take gas temperatures above 1800 F. It can operate at pressures up to atmospheres internal pressure. The nozzles and reaction zones are also designed to operate with coal particles finer than 40 mesh.

We have now above described our present invention on the lines of a preferred embodiment, but our invention is not limited to this in all of its aspects. Various changes may be made in the form and structure of the apparatus n1 mm" on in a... axcnn- -..ru

boiler the gases may departing from the invention or sacrificing any of the advantages. Accordingly it is not our intention to be limited in the scope of this invention except as claimed.

We claim as our invention:

1. An apparatus for producing a fuel gas comprising a substantially vertical chamber for carrying on the primary and secondary stages of the reaction, a plurality of nozzles for introducing the finely divided solid fuel admixed with an oxygenbearing gas positioned on substantially opposite sides of this chamber for the pairing member, at least one nozzle for introducing a gas of the member of the group consisting of steam and carbon dioxide, positioned within this chamber at a point of elevation below that of the nozzle for introducing dispersed fuel, an enlarged chamber overlying the primary reaction chamber and joined directly thereto, a restricted portion above this chamber and a conduit connected to it for leading off the resulting fuel gas, a chamber below the primary reaction chamber and directly joined thereto for collecting the ash.

2. An apparatus for producing a fuel gas comprising a substantially vertical chamber for carrying on the primary and secondary stages of the reaction which chamber is substantially circular in cross-section, a plurality of nozzles for introducing the finely divided solid fuel admixed with an oxygen-bearing gas radially positioned in the cylindrical wall so that the streams from these said nozzles impinge upon each other, at least one nozzle for introducing a gas of the member of the group consisting of steam and carbon dioxide, positioned both tangentially in the interior cylindrical wall and below the level of the nozzles for the dispersed fuel, an enlarged chamber superimposed upon the primary reaction chamber, a restricted portion above this chamber and a conduit connected to it for leading off the resulting fuel gas, and a chamber below the primary reaction chamber and connected thereto for collection of ash.

3. An apparatus for producing a fuel gas com prising a substantially vertical chamber for carrying on the primary and secondary stages of the reaction, which chamber is substantially circular in cross-section, a plurality of nozzles for introducing the finely divided solid fuel admixed with an oxygen-bearing gas radially positioned in the cylindrical wall so that the streams from these said nozzles impinge upon each other, at least one nozzle for introducing a gas of the member consisting of steam and carbon dioxide, positioned both tangentially in the interior cylindrical wall and below the level of the nozzles for the dispersed fuel, a conical enlarging portion superimposed upon the reaction chamber, an enlarged substantially cylindrical chamber superimposed upon this eonical portion, a restricted narrowing portion, above this chamber, a conduit connected to it for leading off the resulting fuel gas, and a substantially cylindrical chamber narrower than the primary chamber positioned below the latter and directly connected thereto for collection of ash.

4. A process for producing a gas of high calorific value comprising the steps of introducing a mixture of finely divided solid fuel into a combustion reaction zone, from a plurality of points impinging the burning jets one against the other whereby turbulence is set up but the burning jets do not directly impinge upon the walls forming the combustion zone, ejecting steam under high pressur below the inlet level of the ejected dispersed fuel contiguous tothe walls of the primary reaction zone thereby causing unconsumed carbonaceous particles to be carried upwardly into the combustion zone and also the steam as it ascends to sweep past the walls of the chamber protecting them from the highest heat, enlarging the cross-sectional stream of fuel gas to cause a decrease in the velocity of its flow whereby a greater time for reaction and settling of suspended particles is afforded, thereafter removing the resulting gas suitable for heating.

5. A process for producing a gas of high calorific value comprising the steps of introducing a mixture of finely divided solid fuel into a combustion reaction zone, from a plurality of points impinging the burning jets one against the other whereby turbulence is set up but the burning 7 jets do not directly impinge upon the Walls forming the combustion zone, ejecting carbon dioxide under high pressure below the inlet level of the ejected dispersed fuel contiguous to the walls of the primary reaction zone thereby causing unconsumed carbonaceous particles to be carriedv upwardly into the combustion zone and also the carbon dioxide as it ascends to sweep past the walls of the chamber protecting them from the highest heat, enlarging the cross-sectional streams of fuel gas to cause a decrease in the velocity of its flow whereby a greater time for reaction and settling of suspended particles is afforded, thereafter removing the resulting gas suitable for heating.

6. A process for producing a gas of high calorific value comprising the steps of introducing a mixture of finely divided solid fuel into a combustion reaction zone, from a plurality of points impinging the burning jets one against the other whereby turbulence is set up but the burning jets do not directly impinge upon the walls forming the combustion zone, ejecting steam tangentially under high pressurebelow the inlet level of the ejected dispersed fuel contiguous to the wall of the primary reaction zone thereby causing unconsumed carbonaceous particles to be carried upwardly into the combustion zone and also the steam as it ascends to sweep past the walls of the chamber protecting them from the highest heat, enlarging the cross-sectional stream of fuel gas to cause a decrease in the velocity of its flow whereby a greater time for reaction and settling of suspended particles is afforded, thereafter removing the resulting gas suitable for heating.

LOUIS L. NEWMAN. JACK T. DONOVAN.

No references cited.

Claims (1)

1. 6. A PROCESS FOR PRODUCING A GAS OF HIGH CALORIFIC VALUE COMPRISING THE STEPS OF INTRODUCING A MIXTURE OF FINELY DIVIDED SOLID FUEL INTO A COMBUSTION REACTION ZONE, FROM A PLURALITY OF POINTS IMPRINGING THE BURNING JETS ONE AGAINST THE OTHER WHEREBY TURBULENCE IS SET UP BUT THE BURNING JETS DO NOT DIRECTLY IMPINGE UPON THE WALLS FORMING THE COMBUSTION ZONE, EJECTING STEAM TANGENTIALLY UNDER HIGH PRESSURE BELOW THE INLET LEVEL OF THE EJECTED DISPERSED FUEL CONTIGUOUS TO THE WALL OF THE PRIMARY REACTION ZONE THEREBY CAUSING UNCONSUMED CARBONACEOUS PARTICLES TO BE CARRIED UPWARDLY INTO THE COMBUSTION ZONE AND ALSO THE STEAM AS IT ASCENDS TO SWEEP PAST THE WALLS OF THE CHAMBER PROTECTING THEM FROM THE HIGHEST HEAT, ENLARGING THE CROSS-SECTIONAL STREAM OF FUEL GAS TO CAUSE A DECREASE IN THE

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