An Improved Process for Denitrating Acid which has been used in the Nitro-glycerine Manufacture.
Year: 1896

page_text: An Improved Process for Denitrating Acid which has been used in
the Nitro-glycerine Manufacture.
We, GEORGE KYNOCH AND COMPANY LIMITED, Manufacturers, and ALLAN THOMAS
COCKING, Engineer, both of Lion Works, Witton, in the County of Stafford, do hereby
declare the nature of this invention to be as follows:-
When acid has been used for nitrating a charge of glycerine in the nitro-glycerine
manufacture, all the nitro-glycerine possible is carefully skimmed off. There still
remains, however, some nitrated carbonaceous matter of an extremely unstable kind
which it is necessary to decompose before treating the sulphuric acid in order to
concentrate it again, and make it fit for re-use. The usual process for this purpose
consists in heating the acid up gently to a sufficient extent to cause decomposition.
Our invention consists in a special and continuous method of producing this
heating and maintaining the heating by the continued decomposition of the nitrated
carbonaceous compounds.
In carrying our invention into effect according to one modification we provide a
small vessel of suitable material into which we place a little water, preferable hot.
We then run in upon this water a portion of the acid to be treated. The mixture of
the sulphuric acid and water at once generates a considerable amount of heat and starts
the decomposition of the nitro compounds in the small quantity of acid at first so
heated. The acid is then allowed to flow into the same vessel at a rate found by
experiment. The initial heat is kept up by the continued decomposition of the
nitrated matter in the acid so added. The acid overflowing from this vessel is thus freed
from the dangerous carbonaceous nitrated matter, and it only necessary to regulate
the flow in order to secure the continuous purification of the acid as it flows in.
Our invention partly consists in starting the heating of the acid by mixing it with
water as described, and partly in causing acid to flow into a vessel slightly heated to
the point proper for securing continuous decomposition.
In some cases we find it advantageous to heat the acid in the first instance by
passing steam into it, in which case the heat is derived from two sources, the heat of
the steam and the heat due to its action on sulphuric acid.
To maintain the vessel at the proper temperature for decomposition a steam coil
may be used.
Dated this 10th day of October 1896
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.

page_text: An Improved Process for Denitrating Acid which has been used in
the Nitro-glycerine Manufacture.
We, GEORGE KYNOCH AND COMPANY LIMITED, Manufacturers, and ALLAN THOMAS
COCKING, Engineer, both of Lion Works, Witton, in the County of Stafford, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
When acid has been used for nitrating a charge of glycerine in the manufacture of
nitro-glycerine, all the nitro-glycerine possible is carefully skimmed off. There still remains
however some nitrated carbonaceous matter of an extremely unstable kind which it
is necessary to decompose before treating the sulphuric acid in order to concentrate
it again, and make it fit for re-use.
The usual process for this purpose consists in heating the acid up gently to a
sufficient extent to cause decomposition. Our invention consists in a special and
continuous method of producing this heating and maintaining the heating by the
continued decomposition of the nitrated carbonaceous compounds present in the
inflowing acid.
In carrying our invention into effect according to one modification we provide a
small vessel of suitable material into which we place a little water preferably hot.
We then run in upon this water a portion of the acid to be treated. The mixture of
the sulphuric acid and water at once generates a considerable amount of heat and
starts the decomposition of the nitro compounds in the small quantity of acid at
first so heated. The acid is then allowed to flow into the same vessel at a rate found
by experiment. The initial heat is kept up by the continued decomposition of the
nitrated matter in the acid so added. The acid passing from this vessel is thus freed
from the dangerous carbonaceous nitrated matter, and it is only necessary to regulate
the flow in order to secure the continuous purification of the acid as it flows in.
Our invention consists partly in starting the heating of the acid by mixing it with
water as described, and partly in causing acid to flow into a vessel slightly heated to
the point proper for securing continuous decomposition. In some cases we find it
advantageous to heat the acid in the first instance by passing steam into it, in which
case the heat is derived from two sources, the heat of the steam, and the heat due to
its action on the sulphuric acid. To assist in maintaining the vessel at the proper
temperature for decomposition a steam coil may be used.
Referring to the accompanying sheet of drawings, Figure 1 is an elevation, and
Figure 2 a plan of an apparatus to illustrate one method of carrying our invention
into effect. A is a tank in which the acid to be purified is placed. It has an
outlet pipe governed by an outlet cock A¹; B is a small spherical or other shaped
vessel placed in a suitable mounting, and having a cock B' to regulate the outflow of
purified acid into the receiver C. The method of working is as follows:-
The tank A is kept supplied with the acid to be purified. The acid flows by
means of the cock A' and the pipe A2 into the vessel B, in which a suitable quantity
of water, preferably hot, has been placed, such that by its reaction with the inflowing
acid sufficient heat is generated to start the decomposition of the nitrated carbonaceous
matter. When the action is thoroughly started and the vessel B partially filled, the
cock B¹ is opened to such an extent that the level of the liquor in B is kept constant.
The cocks A and B are then adjusted to give the rate of flow which will allow of
proper purification of the acid.
Having now particularly described and ascertained the nature of

page_text: invention and in what manner the same is to be performed, we declare that what we
claim is ;-
1. In the purification of acid which has been used for nitrating glycerine in
the manufacture of nitro-glycerine or similar compounds-the method of effecting
the purification continuously by means of the heat generated by the decomposition
of the impurities present in the acid, substantially as described.
2. In apparatus for carrying out the purification of acid as above the use of acid
containing vessels arranged each to supply the next in the series with acid by
gravity, the second being suitably jacketted to retain heat or steam jacketted to
supply heat for maintaining the temperature necessary for the decomposition,
substantially as described.
3. In apparatus for purifying acid as above, the method of starting the decomposition
of the nitrated carbonaceous matter present, by introducing a suitable quantity of
water into the second vessel, then starting the flow of acid into the said vessel and
thus causing the generation of sufficient heat to start the decomposition, substantially
as described.