US887145A - Process of desulfurizing coke. - Google Patents

Description

ERASTUS L. STONER, OF- SOOTTDALE, PENNSYLVANIA.

PROCESS OF DESULFURIZING COKE.

Specification of Letters Patent.

Patented May 12, 1908.

Application filed November 9, 1907. Serial No. 401,407.

To all whom it may concern;

Be it known that I, ERASTUS L. STONER, a

citizen of the United States, residing at Scottdale, in the county of .VVestmoreland and State of Pennsylvania, have invented or discovered new and useful Improvements in Processes of Desulfurizing Coke, of which the following is a specification.

My invention relates to processes of eliminating sulfur from coke and its object is to improve the quality of coke by removing the sulfur t0 the desired limit by the use of reagents involving chlorin.

Sulfur in coal usually exists in the form of pyrites (FeS gypsum or calcium sulfate (CaSQQ, or organic-sulfur, which is sulfur combined with the carbon, hydrogen and oxygen of the coal.

It is my urpose in the present specification to deal on y with pyrites as it exists in the coal and is transformed to other chemical forms by the coking processes, but it is to be understood that I do not waive the right to protection herein for all uses to which my claims may apply, whatever the character of the combinatlons with sulfur may be.

In the coke-burning processes now in use, one-half of the sulfur is, under very favorable circumstances, volatilized, if the organic sulfur is not present in excessive quantity. The sulfur expelled comes partly from that which is resent in the form of organic compounds, 'ut for the larger part form that which is present as yrites, or di-sulfid of iron, the sulfur of whlch is given ofi, even at a low temperature, as sulfur vapor. The statement in regard to one-half of the sulfur being ex elled by the usual coking processes is exemp ified by the following chemical re action: I

in the coke is, owing to the loss in weight in the coking process increased from one-third to one-half, so that in reality only about onefourth of the original per cent. of sulfur is eliminated in the ordinary method of coking The organic sulfur remains for the most art in the coke. part of the volatile sulfur will also be retained by certain constituents of, the ash, especially com ounds of iron, such as the carbonate, oxi and silicats, and also compounds of calcium and magnesium. These compounds of iron are reduced in the process of coking by compounds of carbon to the metallic condition, and this even at a low red heat. The reduced iron, by'virtue of its powerful affinity for sulfur, combines with a part of the sulfur set free from the original pyrites (FeS,) in the coal, to form iron sulfid (FeS).

The carbon compounds formed in the coke oven and containin sulfur, as carbon di-sulfid (CS form sulfi s with iron and with the red-hot oxids of the alkali metals. The sulfates resent, especially gypsum (CaSO are partia 1y reduce to sulfids in the. oven.

My-process is based on the law that all sulfids are decomposed more or less readily by hydrochloric. acid gas (HCl), hydrogen sulfid (H 8) and a chlorid-being produced, and in some cases sulfur being also eliminated, and consists in chlorinating the coke preferably at or near the completion of the coking rocess. This process is greatly facilitated 1f the sulfids are at a red heat such as is usually found in the ovens at the close of the coking process, or after the volatile matter has been practically driven off. The law above stated may be illustrated by the chemical equations in which some of the sul-' fids that form a part of the coke are used, for example:

From these formulae, it is seen that the sulfids of the coke are converted to volatile and soluble chlorids while the sulfur passes off as hydrogen sulfid, which may later be subjected to an oxidizing influence. The remaining soluble chlorin salts may be washed from the coke by the usual frwatering out processes.

Chlorin gas forms the basis of my rocess for reducing the sulfur in the coke. his gas may be generated in any manner that best suits the circumstances. The chlorin gas is preferably passed into superheated steam and then the resulting gases are applied-to the cokein' the ovens. These gases are expressed by the followingchemical reaction:

In my roces's it is definitely understood that the c lllorin gas and superheated steam must be transmitted. through a chamber heated to bright redness and then the resulting mixed gases of HCl and 0, while still in a hi hly heated condition, are applied to the coIre. 4

In my process it is essential that both the mixed gases be in a highly heated condition and the coke red-hot, for a two-fold purpose;

first, that the various sulfids, whichmust be in such condition as has been enunciated in the chemical law hereinbefore laid down,

may be readily decomposed by the HCl gas:

secondly, that the application of the gases -may haveno quenching effect u on the coke, since it is not the urgose of t e proce ess to fiiench the coy means of the gaseous to the underlying principle of the rocess; namely, a red-hot condition of'all'su ds for a successful reduction thereof.

, In addition to the above chemical and 1 physical laws of the process, I wish to point out one other important factor. It will be noted'that it is a mixture of su erheated gases'that is sup lied to the redot coke, which is com oseil of I-ICl and O. The action of the H 61 gas has been described and forms the primary feature of the process.-

The secondary chemical element is the ,free Q and its action upon the various compounds in the coke. The. free 0' gas, actin' meritoriously, may artly oxidize the su fids of the coke to oxi s of the respective elements thus freeing the sulfur as an oxid, or may Cl and 0. Such an arrangement 'would stultify and be diametrically opposed oxidize the H 8 to water and an oxid of sul fur; and, acting deleteriously, the freeO gas may destroy a certain part of the carbon of the coke. a r

. I do not wish to restrict m self to any of the above reactions for free 'It may react in any one and in all of theabove re- 7 scribed ways and in other ways not descr1 ed in the process.

By the above minutiae of the process tI- claim a new process for desulfurizing coke,

differing materially from any process now extant. v

I do not restrict myself to any method of applying the chlorinating gases to the coke. It may be passed through the same from the bottom or sidesor both, or from the top.

I do not restrict myself to the recise compounds with chlorin although have mentioned the use of hydrochloric acid gas.

The strength of the h drochloric acid may be varied in any desire way, as by-varying' the amount of steam used withthe chlorin. I claim' i f" 1. The process of treating cokemade from coal containing sulfids, which consists in subjecting the coke to the action of a chlorinatlng gas at the close of the coking process and then Watering out the fire and thereby Washing out the remaining soluble salts.