Year: 1886

page_text: Date of Application, 5th June, 1886.
Complete Left, 5th Mar., 1887.
Complete Accepted, 3rd June, 1887.
I, CARL FRIEDRICH CLAUS, of Merton Road, South Wimbledon, in the county of
Surrey, Chemist, do hereby declare the nature of this Invention to be as follows:-
In the system of purification of coal gas by ammonia referred to in the Specifications
of my applications for Letters Patent Nos. 7580 and 7584 bearing even date herewith,
the ammonia naturally contained in the crude gas is constantly withdrawn for sale
while a quantity or stock of ammonia is kept in circulation for the purpose of
purification.
Now my present invention has for object the convenient and economical removal of
this surplus ammonia. I can effect this in two different ways:
(1.) In the purifying plant referred to in my above mentioned specifications.
carbonic acid and sulphuretted hydrogen are expelled from the liquor and travel
towards the sulphur kiln as therein described. In the first tower after the heating
towers, that is in tower No. 3. in the series that I have used in the said Specifications
by way of illustration, little besides carbonate of ammonia is found in the liquor,
because the carbonic acid issuing from the heating towers decomposes the sulphide of
ammonium as it meets it, sending sulphuretted hydrogen forward towards the sulphur
kiln. The liquor which enters the heating towers (Nos. 4. and 5.) consists chiefly of
carbonate of ammonia. The requisite surplus ammonia equal to that contained in the
crude gas may therefore be withdrawn either from one of the heating towers or from
the tower next it in the form of nearly pure carbonate. It may be withdrawn either
as liquid, or as vapour from the upper part of the tower. In either case it is carried
into a cool vessel where it may be allowed to crystallize or be dissolved in water.
(2.) The other mode for the removal of the surplus ammonia consists in its
conversion into sulphate of ammonia.

page_text: For this purpose the wash tower No. 1. or the equivalent sulphuric acid catch tower
may be replaced by one or more lead lined towers filled with pebbles or the like down
which a regulated quantity of sulphuric acid trickles.
A regulated quantity of warm ammoniacal vapours from one of the heating towers
or of one of the other purifying towers passes into the bottom of the sulphuric acid
tower, or one of the towers. The strong solution of sulphate of ammonia which flows
from the bottom of the sulphuric acid tower is allowed to crystallize and the mother
liquor is returned to the tower.
The gases evolved are carried to the sulphur kiln and thus there is no risk of loss of
ammonia or of nuisance.
W. LLOYD WISE.
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Preparation of Ammonia Compounds from
Coal Gas.
I, CARL FRIEDRICH CLAUS, of Merton Road, South Wimbledon, in the County of
Surrey, Chemist, 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 :—
In the system of purification of coal gas by ammonia referred to in the specification
of my applications for Letters Patent No. 7580 and No. 7584 bearing even date
herewith, the ammonia naturally contained in the crude gas is constantly or
periodically withdrawn for sale while a quantity or stock of ammonia is kept in
circulation for the purpose of purification.
Now my present invention has for object the convenient and economical removal
of this surplus ammonia. I can effect this in two different ways, according to one of
which carbonate of ammonia is produced whilst according to the other sulphate of
ammonia is produced; and each of these substances is, according to my invention,
produced without special distillation of the liquor such as heretofore has been
necessary in order to produce by the methods that have been adopted either carbonate
of ammonia or sulphate of ammonia. By special distillation I mean the separate
distillation of gas liquor for the express purpose of proparing ammoniacal compounds

page_text: as distinguished from the heating of gas liquor to obtain caustic ammonia in and for
the purification of coal gas; so that it will be understood that by my invention one
heating is made to serve a twofold purpose.
I will describe my invention as carried out, first, by converting the surplus
ammonia into carbonate of ammonia, and secondly, by converting the surplus
ammonia into sulphate of ammonia.
(1) In the purifying plant referred to in the above mentioned specifications,
carbonic acid and sulphuretted hydrogen are expelled from the liquor, and travel
towards the sulphur kiln as therein described. In the first tower after the heating
towers, that is in tower No. 3, in the series that I have first described in the said
specifications by way of illustration, little besides carbonate of ammonia is found in
the liquor, because the carbonic acid issuing from the heating towers decomposes the
sulphide of ammonium as it meets it, sending sulphuretted hydrogen forward towards
the sulphur kiln. The liquor which enters the heating towers (Nos. 4 and 5 in the
first described arrangement of plant in the said former specifications) consists chiefly
of carbonate of ammonia. The requisite surplus ammonia equal to that contained in
the crude gas may therefore be withdrawn either from one of the heating towers or
from the tower next it in the form of nearly pure carbonate. It may be withdrawn
either as liquid, or as vapour, from the tower.
In either case it is carried into a cool vessel where it may be allowed to crystallize,
or be dissolved in water. Suitable condensing vessels may be constructed in various
ways. In the annexed drawing Figs. 1 and 2 (sheet 1) there is shown an arrange-
mont by way of example. Let 3 be the tower referred to as No. 3 in the arrangement
of plant first described in my said former specifications. a is a closed tank of cast or
wrought iron provided with inlet pipe having valve c, and outlet pipe d having
valve e for the gases; fis a cock (or there may be more than one) at the bottom for
the purpose of draining off the condensed liquid; g is a removable lid to permit of
removing the solid product.
The hot gases, which consist of ammonia, carbonic acid and water, sometimes
accompanied by a little sulphuretted hydrogen, on entering the tank a are condensed,
and, according to the proportions in which the various gases are present, there is
formed either a deposit of solid carbonate of ammonia, or a concentrated solution of
the same, which may or may not be accompanied by a small portion of sulphido of
ammonium.
For greater convenience of working, the tank is, in the arrangement illustrated,
surrounded at the sides and bottom with a jacket h, capable of being supplied with
either warm or cold water. By maintaining the temperature slightly above the
crystallizing point of the solution, the deposition of crystals in the tank is prevented,
and the warm saturated solution is run off into closed vessels (not shown) in which
it will in some cases (depending on the proportions of ammonia and carbonic acid and
water) deposit crystals of carbonate of ammonia. When there is such deposition,
the mother liquor may be drained off and returned to the heating towers. The
crystals may then be washed with a saturated solution of carbonate of ammonia to
free them from adhering mother liquor.
As the composition of the gases is liable to vary at any particular point of the
apparatus in which the decomposition of the gas liquor is effected, it is desirable to
provide connections from several points of the apparatus to the condensing tank.
Such connections are, in the example illustrated, shown at i, k, and 7. The connecting
pipes to and from the condensing tank should be provided with steam or hot water
jackets, or be covered with some non-conducting material to prevent deposition of
solid carbonate of ammonia in them.
(2) The other mode of removing the surplus ammonia consists in its conversion
into sulphate of ammonia. This may be conveniently effected by substituting for the
wash tower No. 1, (in the second arrangement of plant described in the before
mentioned specifications), or the equivalent sulphuric acid catch tower, one or more
lead lined towers filled with pebbles or the like down which a regulated quantity of
sulphuric acid trickles.

page_text: A regulated quantity of warm ammoniacal vapours from one of the heating towers
or from one of the other purifying towers passes into the bottom of the sulphuric
acid tower, or one of the towers. The strong solution of sulphate of ammonia which
flows from the bottom of the sulphuric acid tower is evaporated, if necessary, allowed
to crystallize, and the mother liquor is returned to the tower.
The gases evolved are carried to the sulphur kiln, and thus there is no risk of loss
of ammonia, or of nuisance.
Referring to the annexed drawing, (Fig. 3 of the second sheet) No. I is the sulphuric
acid catch tower, No. II is the scrubber tower corresponding to Nos. 2 and 3 in the
first arrangement of plant described in the before mentioned specifications, and
No. IV is the heating apparatus. On the pipe a, by which the gases from the heating
this pipe
apparatus No. IV pass to No. II, is a branch pipe provided with valve
acts as a bye-pass to the tower No. II, by which any desired amount of the warm
ammoniacal vapours from No. 1V may be admitted direct into the acid tower No. I
without passing through No. II. By opening or closing the valve c the amount of
ammonia entering the acid tower No. I may be adjusted so as to be practically equal
to the ammonia entering the scrubbers with the foul gas.
As a modification of the just described method, an acid saturator, such as is
ordinarily used in the manufacture of sulphate of ammonia from gas liquor might be
interposed between the tower No. 2 in the before mentioned series, and the acid catch
tower No. 1. In this case the gases would pass first through the saturator and then
through the catch tower, and the acid would be fed into the top of the catch tower and
would run thence into the saturator. This arrangement is illustrated at Fig. 4 of the
Or the
annexed drawings, s being the saturator and the other parts as in Fig. 3.
catch tower might be dispensed with entirely, assuming the absorption of the ammonia
in the saturator to be sufficiently complete.
Having now particularly described and ascertained the nature of the said invention,
and in what manner it is to be performed, I declare that what I claim is :
-
1. In the purification of coal gas, the method substantially as described of removing
surplus ammonia by converting the same, without special distillation, into carbonate
of ammonia, in the manner set forth.
2. In the purification of coal gas, the method substantially as described of removing
surplus ammonia by converting the same, without special distillation, into sulphate of
ammonia in the manner set forth.
D
1
JC Manch 1007
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.