US1386723A - Method of producing nitrogen compounds during the dry distillation of nitrogenous fuel - Google Patents

Description

can be readily separated from the new r0 7?) r p n] r Pieiahhwl "WALTER OS'I'WAL'D, OF GROSSBOTHEN, NEAR LEIPZIG, GER/TEA:

AEiSaIGrNCUR, BY

OF DELAWARE.

METHOD GT3 PRODUCING NITROGEN COMPOUNDS DURING- il-IE DRY DISTILLATION OF NITROGENOUS FUEL;

No Drawing. Application filed September '7, 1916, Serial lilo. 118,838. Renewed January 27, 1926.

Specification of Letters Patent.

Serial No. 354,748.

To all 21:71am it may concern:

Be it known that LWVALTER QSTWALD, of Grossbothen, near Leipzi Germany, Hans Dowa, have invented a certain new and usei'ul Improved Method of Producing Nitro' gen Compounds During the Dry Distillation of Nitrogenous Fuels, of which the following is a specification.

During the dry distillation of a charge composed of coal mixed with chlorids, it is frequently found that in the pipes of the plant thick tar-like masses are formed which principally consist of ammonium chlorid and cause serious trouble in the operation of the plant. For obviating this defect it has been customary to use so-called wet receivers in which the ammonium compounds in question are carried away partly in aqueous solution.

in the process according to my present invention the opposite procedure is adopted. The invention consists in converting the nitrogen at the outset uniformly into the form of ammonium chlorid, so that it can be readily condensed.

For this purpose, the nitrogen may, for instance, be converted into ammonium chlorid by the addition of chlorids to the charge to be subjected to dry distillation. The temperature of sublimation of ammonium chlorid is about 450 O, so that it gases by fractional condensation.

My present invention, therefore, essentially consists in converting into the form of ammonium chlorid the entire nitrogen, which can be obtained by the dry distillation of the charge. The nitrogen contained in the coal may be divided into two parts, namely into one which may easily be obtained in a bound form, that is the so-called non-fixed nitro-' gen, and into a second part which is not liberated before the pyrogenous destruction 0-2 the colre has started. This latter part may be designated fixed nitrogen. The entire amount of nitrogen is divided in approximately equal parts into fixed and noni'izred nitrogen. In the process according to my present invention only the non-fixed nitrogen can be obtained. It is, however, pos sible by means of my invention to prevent the combustion of the nitrogen compounds which are produced from the non-fixed nitrogen by converting the ammonia into ammonium chlorid. The material increase in the yield of nitrogen is thus partly explained. When the distillation is carried out in the mannercustomary heretofore, only 15% of. the nitrogen of the coal can be won, of the nitrogen remaining as fixed nitrogen in the coke and 15% in the tar. The remaining part of non-fixed nitrogen (about 15% to 20% of the total nitrogen) can be obtained in the process according to my present invention if care is taken that the formation of ammonium chlorid is not diminished owing to lack of water or steam. in order to bind this remaining part of the nitrogen which may be obtained during the dry distillation in the form of ammonium chlorid, according to my invention water or steam is introduced during formation of the ammonium chlorid. This water may consist of the moisture contained in the coal, or a further addition of water may be made, and the action may be enhanced by the water of hydrated salts; however, the preheating of the charge in the retorts should not be suiiicient to expel, as steam, the water added to supplement the moisture contained in the coal. Owing to the addition of chlorids and by regulating the supply of water or steam, it is possible to set free the two constituents of the ammonium chlorid in such a manner that they will be equivalent to each other at any moment of the carbonizing period. This is of special importance, since an excess of free ammonia might be decomposed by glowing walls and since free hydrochloric acid is lia ble to injure the apparatus. The chloride used, may be the chloride oi the alkaline earth metals or hydrochloric acid either in liquid'or gaseous form.

At the same time, obtaining the nitrogen in form oi ammonium chlorid has material advantages as regards the method or working itself. Ammonium chlorid is uniformly volatile, this being exactly contrary to most other nitrogen compounds which have heretofore been found with the usual methods in gas-water and in other constituents of the distillation gases. By simply washing the gas with water and cooling the solution to the temperature of crystallizatiomit is possible to obtain directly, a pure marketable ammonium chlorid instead of theusual complicated mixture of various kinds of nitrogen compounds, all employment of sulfuric The solution obtained by the present method is preferably evaporated in a neutral or slightly alkaline state, and thls can be effected without material expense by waste heat, the ammonium chlorid being obtained.

directly in crystalline form. Lastly, obtaining the nitrogen in the form of ammonium chlorid has the further advantage that the chlorid can easily and cheaply .be freed from impurities not only by recrystallization, but also by re-sublimation. Ammo-' nium chlorid containing 25% nitrogen is richer in nitrogen than-the ordinary com-' IIlGIClEll ammomum sulfate.

1 claim 1. In the dry-distillation or coking of a nitrogenous fuel, the process of obtaining as a by-product the non-fixed nitrogen of the fuel, which consists in mixing a chlorid with the fuel, in heating the mixture in a closed chamber and supplying steam thereto with the exclusion of air, whereby hydro chloric acid is produced and the nitrogen of the-fuel is converted into the form of ammonium chlorid, and in subsequently separating the ammonium chlorid from the remaining products; substantially as described.

2. In thedry-distillation or coking of a nitrogenous fuel, the process of obtaining as a 'by-product, the non-fixed nitrogen of the fuel, which consists in mixing a chlorid with the fuel, in heating the mixture in' a closed chamber and supplying steam thereto with the exclusion of air, the quantity of admixed chlorid being approximately equivalent to the percentage of non-fixed nitrogen in the fuel, whereby hydrochloric acid is produced and nitrogen of the fuel is converted into the form of ammonium chlorid,

and in subsequently separating the ammonium chlorid from the remaining products.

substantially as described.

3. In the dry dlstillation or coking of a nitrogenous fuel, the process of obtaining as a by-product, the non-fixed nitrogen of the fuel, which consists. in'-mixing a hydrated chlorid with the fuel, in heating the mixture in a closed chamber and thereby generating steam therein with the exclusion of air, whereby hydrochloric acid is produced and nitrogen of the fuel is converted into ammonium chlorid, and in subsequently separating the ammonium chlorid from the remaining products, substantiallyas described.

4. In the dry-distillation orv coking of a nitrogenous fuel, the process of obtaining as a by-product, the non-fixed nitrogen of the fuel, which consists in mixing a chlorid with the fuel, in heating. the mixture in' a closedchamber and generating steam therein with the exclusion of air, whereby hydrochloric acid is produced and the nitrogen of the fuel 1s converted into ammonium chlorld, and in subsequently scrubbing the gases produced.

With water and thereby obtaining the ammonium chlorid in the form of an aqueous solution, substantially as described.

In testimony whereof I affix mysign'ature in presence of two witnesses.

. WALTER OSTWALD.

Witnesses:

RUDOLPH FRIOKE, 'THEKLA Fmomi.