US1720290A - Method of operating molten-slag gas producers - Google Patents

Description

- July 9, 1929.

H. .1 F. PHILl PON METHOD OF OPERATING MOLTEN SLAG GAS IRODUCERS Filed Jan. 31, 1923 it A 0 Jm w 4 z 1%.. 1: a, A a f d Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

HENRI JEAN FRANCOIS PHILIBON, OF ST. ETIENNE, FRANCE, ASSIGNOR TO THE SOCIETE ANONYME LAIB CHAUD, ST. ETIENNE (LOIRE), FRANCE, A CORPO- RATION 0F FRANCE.

METHOD OI OPERATING IOLTEN-BLAG GAS PRODUCERS.

Application filed January 31, I928, Serial No. 816,169, and in Belgium March 8, 1922.

This invention relates to a method of operating molten slag gas producers. The gasification of combustibles is usually effected by means of apparatus which eliminate the ashes b or residues either in the solid or in the molten state.

The earliest forms of gas producers, invented about the ear 1840 by Ebelman, were of the kind yiel ing molten slag. In such producers air was blow upon the combustible fuel through one or more tuy'eres, and upon increasing the pressure of the blast there resulted a suflicient rise in temperature within the apparatus to bring about a scorification and in some cases even a fusion of the resiues.

In the operation of gas producers of this character if the ashes or residues of the combustibles are of a fusible nature or if suitable fluxes are added, fusion of the residues can be obtained and thereby for a short time operation of the producer secured. It is in this Way that certain installations have been able to function, but their duration has always been very short; as soon as the factors (nature of the fuel, variation in the content of the slag and the like) favorable to successful operation were changed, stoppages were found to occur within the apparatus rendering its further continued operation impossible. Furthermore, in all gas producers hitherto operated with success, the gases have been evacuated at the producer top at a very high temperature.

It has heretofore been proposed to increase the temperature within the producer by recuperatinv a portion of the heat contained in these high temperature gases, and for this purpose the hot gases are made to traverse 4o nests of tubes through which the air to be heated was passed in the reverse direction. This method has made it possible to deliver to the tuyeres a heated blast, but rarely heated to a temperature exceeding 200 C.

The condition of the practical art is such that at the present time regular and eflicient operation of gas producers of this type has been carried on for any considerable period onlyby treating special coke as the fuel in I the producers, and operating the same at a high capacity, with suitable fluxes. So far as I am informed, however, such apparatus is not satisfactory when inferior fuels are employed or when the output of the producers is reduced, say to 50% of its maximum capacity, since there is a risk of clogging scorification and the regular operation of the producer becomes uncertain.

The object of the resent invention is to provide a method 0 operating a gas pro ducer whereby the residues of the charges employed shall be reduced to a state of great fluidity and thus readily evacuated from the apparatus in a liquid state, even if the producer is worked much below its maximum '65 capacity, thereby avoiding interruption to the operation of the apparatus which would result from extended scorification and consequent clogging of the gas producer and final stoppage of its operation.

A further object is to secure the combustion of the carbon to carbon monoxide as completely as possible. In short, the object is to secure a continuous operation of a gas producer adapted to treat all manner of combustibles, capable of being operated much below its normal capacity, and yieldinga gas richer in carbon monoxide than would producers heretofore in use. Further benefits will result from the practice of the invention so whichit is not necessary here to detail.

The present invention consists of a method of operating a molten slag gas producer which includes the step of blowing on the fuel a very highly heated blast. I have found that by as heating such blast to approximately 500 C. or above (depending upon the character of fuel, fluxes, etc.) I obtain a very fluid slag and all of the residues of the charges whether fuelsv are employed alone or have added fluxes of any kind, such as calcium carbonate, are reduced to a state'of great fluidity, whereby they may be readily run out from the producer. For example, with a blast of 800 C., or more, delivered through tuyeres into the producer, as a very high temperature (2000 C. or more) within a certain zone or portion of the producer, may be readily produced, which temperature will result in the formation of a fluid slag and the melting of the other residues of the charge as stated. Not only this,but the combustion of the carbon in contact with such high temperature blast is complete and gives approximately only carbon monoxide. The gas obtained may have for example the following composition: carbon dioxide, 1 to 3%, carbon monoxide, 30 to 33%, and nitrogen, 66 to 67%.

There is thus obtained a continuous operation of the producer with all varieties of combustible fuels and, in addition, there is secured, even when the producer is not operated at its normal capacity, a gas richer in carbon monoxide than with ordinary producers.

One form of construction of a gas producer capable of use with the present invention for producing the high temperature blast and molten slag as indicated above is shown by way of example in the accompanying drawing, which represents a longitudinal section of the plant.

The gas producer A is similar to a foundry cupola, the lower section a of which is preferably formed by a thick plate of metal cooled by a water spray. The water is distributed by one or more circular rings'b, b, from which it is delivered in the form of jets which spray upon the plate a. The sprayed cooling water is collected just above the tuyeres 0 by an angle ring d riveted upon the plate a of the producer.

The producer is provided with two tap holes e, f e is situated at the very bottom of the apparatus to receive the cast iron orother metal formed by the reduction of oxides which may be present in the combustibles, and the other tap hole I is arranged at the top of the hearth-well and serves to discharge. the slag. The space around the hopper g of the producer is closed to permit the collection of the combustible gases by means of a takeoff pipe 12.; a branch pipe 0, from said takeoff pipe n, leads off a part of said gases,

which is used to heat the blast.

The means for heating the blast to the high temperature required is here shown as a special continuous recuperator apparatus supplied by gas led through the pipe 0 to the burner it, through which air is also admitted. It is to be understood, however, that any other suitable fuel may be employed in the apparatus for heating the blast, and that instead of a continuous air heater commonly called a recu erator, as illustrated in the accompany-i ing rawing, any heater of the reversing type known as a regenerator) could he used for t e same purpose. The heating gases, the

path of which is represented by the single arrows, are burnt in a combustion space i in the secondary recuperator k and travel to the flue Z after .having circulated successively around the nests of tubes 7: in the secondary recuperator k, and similar nests m in the primary regenerator m. The air to be heated for the blast follows the path represented by the double arrows and reaches the tuyeres 0 of the producer after having passed successively through the interior of the primary and secondary nests of tubes 'm. and la. By this means it is possible to heat the blast to as high a temperature as may be required for the character of fuels and other conditions obtaining in the producer. I have found that the temperature of the air blast as it is delivereid into the combustion chamber of the producer by the tuyeres should be approximately 500 C. or above and that with varying classes of fuel and conditions of operation, such as presence of fluxes and the like, it is necessary to increase the temperature of the blast very materially above 500 0., going even as high as 800 C. or more. In all cases, however, if the temperature of the blast is sufliciently high, the fluidity of the slag is secured and all of the residues of the combustibles, Whether alone or with added fluxes, are reduced to a state of great fluidity, thereby enabling them to be very easily evacuated from the apparatus in .a liquid state. This renders possible a continuous operation of the producer without clogging by reason of scoritication of the ashes and fluxes as in producers heretofore employed.

Moreover, the highly heatedbla'st of air results in the direct production of carbon monoxide near the bottom of the charge and consequently there is a limited highly heated zone at the bottom of the charge in which the temperature drops rapidly.

While for the sake of clearness one expression of the inventive idea has been herein described and illustrated in detail, it is'to be understood that the invention is susceptible of various expressions within the limits of the appended claims. It is further to be understood that where in the description and claims the word charge is used, I mean either a body of fuel alone, or a fuel or combustible associated with fluxes, or any other added matter dependent upon the uses to be subserved.

What is claimed is 1. In a method of operating a gas producer, the step which consists in maintaining in a limited zone adjacent the bottom of the charge in the gas generating chamber, a temperature of substantially 2000 C. or above, by delivering an air blast heated to 500 C.

' or above, into the generating chamber at said Water-cooling externally the lower part of the gas generating chamber.

3. In a method of operating a molten residue gas producer, the steps consisting in de- 5 livering into the gas generating chamber an air blast heated to a temperature of approximately 500 C. or above, and in externally water-cooling the lower part of the gas generating chamber at a point above the level of the blast inlet into said chamber. 10

In testimony whereof I have signed my name to this specification.

HENRI JEAN FRANCOIS PHILIPON. [L. 5.]

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