USRE11995E - Process of making sulfuric anhydrid - Google Patents

Description

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UNITED STATES PATENT OFFICE.

HENRY SPENCER BLACKMORE, ()F MOUNT VERNON, NEW YORK.

PROCESS OF MAKING SULFURIC ANHYDRID.

SPECIFICATION forming part of Reissued Letters Patent No. 11,995, dated May 27, 1902. Original No. 886,022, dated November 6,1901. Application for reissue filed Earth 29, 1902. Serial No. 100,639.

To to when: it may concern:

Be itkuown that I, HENRY SruNoEnBLAcic MORE, a citizen of the United States, residing at Mount Vernon, in the county of We'stchester and Stateof New York, have invented certain new and useful Improvements in Proc esses of lroducingSulfuric rxnhydrid; and I do hereby declare the following, to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertui us to make and use the same.

The object of my invention is to produce sulfuric anhydrid, (sulfur trioxhlgj and it consists in oxidizing sulfur diox d by the action of a metallic oxid or substances containing the same-in other words, substances containing an oxid.izing'agcnt,such as metallic oxid.

My invention also consists in producing sulfuric anhydrid by oxidizing sulfur dioxid at a temperature maintained below the dissooiating'point of sulfuric anhydrid, which maintenance of temperature and the results attained thereby are hereinafter set forth.

The histo y of the art to which my invention appertains shows that sulfuric anhydrid (S0,) has heretofore been produced by the combination of sulfur dioxid (S0,) with oxygen. It also shows that the product of the prior processes has always fallen below the theorectical yield-that is to say, that the quantity of S0 actually produced by the processes heretofore known has probably not ex ceedcd sixtyscven per cent. of the amount which a complete chemical union of the sulfur dioxid and oxygen should produce. Pro fessor Lung-e, speaking of these prior processes at the end of the year 1897 in The Min oral frtllltsire w; of H66 United States and other C'rmuir'ics, page 130, said: Probably sixty seven per cent. must be considered very good work, and the remaining thirty-three per cent of suliurous acid must be sent intn lead chambers, together with better gas from While the fact of this low percentage of yield has long been known to those who are familiar with the art, no providus investigator has ascertained the cause of the same or suggested a remedy for tho diiliculty. l have discovered that the delicicncy in the quantity of sulfuric anhydrid was due to the high and accumulating heatat which the reaction between the sulfur dioxid and the oxygen was conducted and that by properly controlling the temperature of re action a substantially complete union of the sulfur dioxid and oxygen and a practically quantitative yield of sulfuric anhydrid may be obtained.

In all previous processes mixtures of sulfur diorid and oxygen or oxidizing agents were heated to the con'ibiningpoiut by the application of extraneous heat; but in the performance of these processes the chemical union of the sulfur dioxid and the oxygen evolved a large amount of heat, which when added to the extraneous or initial heat caused the temperature within the sphere of reaction to rise above the point at which sulfuric anhydrid is dissociated, the result having been in every instance that at least thirty per cent. of the product was by dissociation resolved into sulfur clioxid and oxygen agaimwhich, as stated by Professor Lungc, had to be treated separately in lead chambers, into which better gas from other sources was admitted. It has been proposed to combine volumes of sulfur dioxid and oxygen heated to a combining temperature in the presence of contact substances, such as spongy platinum or oxide of chromium or of iron or of copper, at or about a dull-red heat or somewhat below that term pcruture; but nothing is revealed regarding the excessive accumulation of the heat, 32.2 cahiries per unit, (Thomsen,) which is necessarily liberated by the combination of sulfur dioxid with oxygen; nor is any means indiouted for preventing the heat thus liberated from rising to the dissociating-pointof sullfu ric anhydrld, the combining gases being at an initial temperature,- which by the added heat of combination must necessarily risc'to 3 rich higher degree until the point at which sulfuric anhydrid is dissociated is reached, thus terminating the process unless restrained by somc'rcfrigerative influence, the necessity of which was unknown.

The external heat which I suppby' to theretort is used merely for the purpose of starting the reaction, which after being initiated may be maintained thereby and by the heat which is liberated by the oxidation of the sulproduccd by the proces' -i heretofore known fur ilinxid. The sulfurdioxid may, as here- It is obvious from the foregoing inafter stated, be heated before being admiti ted to the retort in order to assist in the maintenance of the combining temperature within the sphere of reaction. Should the temperature rise too rapidly during reaction, refrigeration may be resorted to for the purpose of keeping the temperature below the dissociating-point of sulfuric anhydrid.

In view of the foregoing it is clear that the temperature must not be allowed to rise above the dissociating-point of sulfuric anhydrid, for otherwise the sulfuric anhydrid, if produced, would either in Whole or in part be dissociated. Should the sulfur dioxid be introduced into the retort without being heated above the ordinary tempe ature of the air, which is its normal temperature, it will act as a refrigerant and by its cooling action operate to keep the temperature within the reaction sphere considerably below the point at which he sulfuric anhydrid dissociates.

It is we known that certain metals-such as iron, copper, &c.-have a variable aflinity for oxygen, according to the temperature at which maintained. For example, steam passed over iron at white heat is decomposed, producing iron oxid and hydrogen gas,while if the temperature of the iron oxid thus produced is lowered to a low red heat and the same hydrogen gas conducted over it the affinities are so reversed that the oxygen is again taken up by the hydrogen, regenerating steam and reducing the iron to a metallic state, known commercially as iron-byhydrogen. Utilizing this property of the metal, I have conducted sulfur dioxid over iron oxid at low temperatures-4. e., below the dissociating-point of sulfur trioxid (sulfuric anhydrid)-and found that it has the property of absorbing the oxygen therefrom, reducing iron oxid,and producing sulfur trioxid, (sulfuric anhydrid,) which distils or sublimes and is finally condensed.

The reaction which takes place may be illustrated by the following chemical formula or equation: Employing ferric oxidthat the temperature must not be maintained above the dissociating-point of sulfur trioxid, (sulfuric anhydrid;) otherwise it would preclude its formation.

The manner in whichl proceed to carry out my process on a commercial scale is to placeinaretortorcontainerironoxidandtem porarily heat the same slightly-say about 212 Fahrenheit-to start the operation by eliminating moisture, then conveying over or through the said iron oxid sulfur dioxid which has preferably been heated, so that thereafter the reaction may be maintained by the occluded heat of thesuifur dioxid,aud thus 4 avoiding the application of directly-applied heat as much as possible, which is hard to regulate and keep below the dissociating-point of the sulfur trioxid (sulfuric anhydrid) produced. The heated sulfur dioxid passed over the metallic oxid in ordinary cases sufficiently heats the same after starting the reaction to assure the reaction continuously until the iron oxid is reduced. Also considerable heat is liberated by the oxidation of the sulfur dioxid in direct contact with the metallic oxid, so that the reaction is practically maintained after the first heating, which merely serves to start the reaction, by the combined heat of that occluded by the introduced sulfur dioxid and thatliberated during reaction. The sulfur trioxid (sulfuric anhydrid) produced is distilled or sublimed and finally condensed. The iron reduced by oxidation of the sulfur dioxid is then reoxidized by simply elevating the temperature and passing air or oxygen over the same, so that the oxidizing agent (metallic oxid) is regenerated and reused over and over again without loss, thus rendering the process practically continuous.

It is obvious that other metals, such as copper, may be employed without departing from the spirit of my invention, which specifically consists in oxidizing sulfur dioxid by the action of metallic oxid.

If metallic oxid heats too rapidly during reaction, it may be refrigerated to keep below dissociating-point of sulfuric anhydrid.

When cupric oxid is employed, the reaction may be illustrated by the following chemical formula or equation:

SO +CuO=Cu+SO The term metallic oxid or iron oxid as herein employed is intended to include any substance containing a metallic oxid which will give up its oxygen to oxidize sulfur dioxid to sulfur trioxid under the conditions described as well as the pure metallic oxid per 36.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The process of producing sulfuric anhydrid (S0,), which consists in oxidizing sulfur dioxid by the action of metallic oxid, substantially as described.

2. The process of producing sulfuric anhydrid, which consists in conveying sulfur dioxid in contact with metallic oxid at a temperature below the dissociating-point'of sulfur trioxid.

3. The process of producing sulfuric anhydrid, which consists in exposing a metallic oxid to the action of heated sulfur dioxid while maintaining the temperature below the dissociating-point of sulfuric anhydrid.

4. The continuous process of producing sulfuric anhydrid (S0,) which consists in exposing metallic oxid to the action of sulfur dioxid at a temperature below the dissociating-point of sulfur trioxid, conveying the IIO sulfur trioxid produced to a condenser, elevating the temperature of the metallic residue, passing oxygen over the same, cooling, exposing the product to the action of more sulfur dioxid and continuing the process as before.

.5. The process of producing sulfuric anhydrid, which consists in'exposing iron oxid to the action of sulfur dioxid in a heated state and maintaining the temperature below the dissociating-point of sulfuric anhydrid, substantially as described.

6. The process of making sulfuric anhydrid, which consists in oxidizing sulfur dioxid while maintaining the temperature be low the dissociating-point of sulfur trioxid, substantially as described.

7. The process of producing sulfuric anhydrid, which consists in conveying sulfur dioxid in contact with an oxidizing' agent at a temperature below the dissociating-point of sulfur trioxid, substantially as described.

8. The process of making sulfuric anhydrid, which consists in subjecting sulfur dioxid to the action of an oxidizing agent while maintaining the temperature below the dissociating-point of sulfur trioxid, substantially as described.

9. The process of making sulfuric anhydrid, which consists in oxidizing sulfur dioxid and maintaining the temperature below the dissociating-point of sulfur trioxid by refrigeration, substantially as described.

10. The process of making sulfuric anhydrid, which consists in uniting sulfur dioxid with oxygen while maintaining the temperature between the combining and dissociating point of sulfur trioxid by controlled heat and refrigeration, substantially as described.

11. The process of makingacompound composed of one atom of sulfur and three atoms of oxygen which consists in uniting sub stances forming the compound while maintaining the temperature below the dissociating-point of sulfuric anhydrid by refrigeration, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

HENRY SPENCER BLACKMORE- lVitnesses:

(ARREN C. STONE, C. G. WRIGHT.

DEPARTMENT OF THE INTERIOR,

UNITED BTATIB PATENT OFFICE,

\VASHINGTON, D. (3.,Jlarch 25, I908.

iV/iereas, On November 27, W07, the Circuit Court 0! the United States for the Southern District of New York held Reissue Patent No. 11,995 revoked, vacated,

and declared null and void, in a decree which has been recorded in Liber H, 78, page 497, of the assignment records of the United States Patent Oflice,

It is hereby ordered, That the record of the said reissue patent be marked Canaeled. [Ofl'icial Gazette, March 81 1908.]

B. .VIOORE,

( nmm issioner.