Improvements in the Removal of Ammonia from Coal Gas, and in the Manufacture of Ammoniacal Salts therefrom, and in Apparatus Employed in such Process.
Year: 1886

page_text: Date of Application, 30th Apr., 1886.
Complete Left, 29th Jan., 1887.
Complete Accepted, 8th Mar., 1887.
Improvements in the Removal of Ammonia from Coal Gas, and in
the Manufacture of Ammoniacal Salts therefrom, and in Apparatus
Employed in such Process.
We JOSEPH HEPWORTH of the Gas Works Civil Engineer, and EDWARD MARRIOTT
of Rome Street, Chemist both in Carlisle in the County of Cumberland do hereby
declare the nature of this invention to be as follows:-
The objects of this invention are to remove or recover the whole of the ammonia from
coal gas and to manufacture or convert the same into salts of ammonia without the
agency of stills and saturators. It also dispenses entirely with the use of lime and with
the greater part of the fuel employed in such manufacture.
In carrying out this invention we use a neutral solution of either sulphate, muriate,
or any other suitable salt of ammonia, and by introducing this solution into the scrubbers
or washers, or other similar vessel in which the coal gas is being washed, the whole of
the ammonia contained in the said gas whilst passing through the scrubber or washer,
is removed by the solution employed.
When the solution thus charged with an excess of ammonia leaves the scrubbers or
washers or other vessel, it enters into a neutralizing cistern where it is brought into
contact with a supply of acid sufficient to neutralize the free ammonia which it contains.
By this means the free ammonia removed from the gas in the scrubber, washer or other
vessel is again neutralized and made available for further use in the scrubber, washer
or other vessel into which it is again delivered.
By a continuation of this process the solution can be used over and over again
until it acquires a density of forty degrees (Twaddel) or other required strength when
it is removed and evaporated in the usual way.
The sulphuretted hydrogen and the carbonic acid gas liberated in the neutralizing
cistern are carried forward into a purifier charged with oxide of iron or lime and are
thus rendered innocuous.
The apparatus which we employ for the above described process consists of two or
more closed boxes, chambers, or vessels of suitable form, to one part of which other

page_text: smaller boxes or chambers lined with lead (and hereafter called "neutralizers") are
attached, the tops of the said neutralizers being open.
The shape of the neutralizers may be varied without affecting the general principle
of the invention.
Into the neutralizers are carried pipes of suitable diameters for conveying the liquor
from the washers, or scrubbers, and also the acid from a suitable store cistern (fixed
in a convenient situation) to neutralize the ammoniacal liquor as it runs down.
It is preferred that at least two of these boxes should be placed side by side so that
one may be in operation whilst the other is being run off.
Each box or vessel is fitted with three or more pipes, one to carry off the sulphuretted
hydrogen carbonic acid or other gas which may be evolved, (other than ammonia) this
pipe is connected to the gas main at the outlet of such washers or scrubbers and the
gas is carried by this main to the purifiers; a second pipe is attached to the bottom
for emptying the vessel when required, and the third pipe is attached to a pump of
suitable construction, the said pump being used to throw the neutralized liquor back
again to the top of the scrubber, where it is spread by means of a suitable distributor,
flowing down such scrubber in intimate contact with the gas; or into the washer, if
the latter he used, taking up an additional quantity of ammonia which is again
neutralized as before.
The acid store tank is fitted with taps whereby the flow of acid may be regulated,
and a test cock is fitted in a convenient position on the delivery pipe from the pump so
that the ascending liquor can be at any time readily tested.
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicants.

page_text: Improvements in the Removal of Ammonia from Coal Gas, and in
the Manufacture of Ammoniacal Salts therefrom, and in Apparatus
Employed in such Process.
We JOSEPH HEPWORTH of the Gas Works Civil Engineer and EDWARD MARRIOTT
of Rome Street Chemist both in Carlisle in the County of Cumberland 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:―
The objects of this invention are to remove or recover the whole of the ammonia
from coal gas and to manufacture or convert the same into salts of ammonia without
the agency of stills and saturators.
It also dispenses entirely with the use of lime and with the greater part of the fuel
employed in such manufacture.
The nature of our said invention and the method of carrying the same into practical
effect will be readily understood on reference to the annexed sheets of drawings and
the following explanation thereof.
Fig. 1. is an elevation of the apparatus.
Fig. 2. is a section taken vertically through about the line A. B. in fig. 1 and fig. 3.
is a plan view of the same.
In carrying out this invention we uso (instead of plain water for washing the gas) a
neutral solution of either sulphate muriate, or any other suitable salt of ammonia
and by introducing this solution into the scrubbers or washers or other similar vessels
in which the coal gas is being washed the whole of the ammonia contained in the said
gas whilst passing through the scrubber or washer is removed or absorbed by the solution
employed.
When the solution thus charged with an excess of ammonia leaves the scrubbers or
washers ог other vessel by means of the liquor pipes it enters into a lead lined neutralizing
cistern where it is brought into contact with a supply of acid sufficient to neutralize
the free ammonia which it contains. The acid is supplied to this neutralizing cistern
from an acid store cistern above. By this means the free ammonia removed from the
gas in the scrubber washer or other vessel is again neutralized and made available for
further use in the scrubber washer or other vessel into which it is again delivered.
By a continuation of this process the solution can be used for washing the gas over
and over again until it acquires a density of about forty degrees (Twaddell) or other
required strength when it is removed and evaporated in the usual way thus producing
the aminoniacal salts.
The sulphuretted hydrogen and the carbonic acid gas liberated in the neutralizing
cistern are carried forward into a purifier charged with oxide of iron or lime and are
thus rendered innocuous.
In the annexed drawings of the apparatus which we employ for the above described
process a. u. are the washers or scrubbers b. b. pipe from the scrubbers to the
purifiers c. c. are closed liquor tanks chambers or vessels of suitable form to one side of
which other smaller boxes or chambers, d. d. lined with lead (hereinafter called
"neutralizers") are attached, the tops of the said neutralizers being open. The shape
of these neutralizers may be varied without affecting the general principle of the
invention.

page_text: Into the neutralizers d, d. are carried pipes e, e of suitable diameters for conveying
the liquor from the washers or scrubbers a, a also pipes ff to convey the acid from a
suitable store cistern g, g (fixed above in a convenient situation) to neutralize the
ammoniacal liquor as it runs down. It is preferred that at least two of these liquor
tanks e, e and neutralizers d, d should be placed side by side as shown at Figs. 1 and 3
so that the one may be in operation whilst the contents of the other is being run off by
the pipe h, h to the store tanks.
Each box or vessel c, c is fitted with three or more pipes, one i, i to carry off the
sulphuretted hydrogen, carbonic acid, or other gas which may be evolved (other than
ammonia); this pipe is connected to the gas main at the outlet of the washers or
scrubbers a, a and the gas is carried by this main to the purifiers k, k.
A second pipe h, h leading to the store tanks is attached to the bottom for emptying
the Vessel when required as before mentioned and the third pipe 1, 7 is attached to a
pump of suitable construction, the said pump, being used to throw the neutralized liquor
back again to the top of the scrubbers a, a where it is spread by means of a suitable
distributor flowing down such scrubber in intimate contact with the gas (or into the
washer if the latter be used) taking up an additional quantity of ammonia which is
again neutralized as before.
The acid store tank g, g is fitted with taps whereby the flow of the acid may be
regulated, and a test cock is fitted in a convenient position on the delivery pipe from
the pump, so that the ascending liquor can be at any time readily tested.
In cases where there is more ammoniacal liquor produced in the gas works than can
be treated in the above apparatus we employ an additional closed vessel m, m with a
perforated false bottom in the space beneath which leads a gas pipe n, n from the scrubber
outlet. A steam coil o, o is placed in this vessel.
A portion of the ammoniacal liquor which has not been treated by the first process
being admitted into this vessel through a pipe at, or near the top, (not shown in the
drawing), gas from the scrubber outlet is allowed to flow in beneath the perforated
bottom, and bubbling up through the heated liquor extracts the ammonia therefrom and
acts as a carrier to convey the same along the pipe p, p to the scrubber inlet whence it is
taken up by the other concentrated liquor and proceeds to the neutralizer as before
described.
The water in the tank or vessel m, m when thus deprived of its ammonia is allowed
to flow away to the drains by the pipe 7, the vessel m, m is re-charged and the
operation proceeds as before.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed we declare that what we claim is:-
First: The removal or recovery of the ammonia from coal gas in a concentrated
form by introducing into the scrubbers, washers or other similar vessels wherein the
coal gas is being washed a neutral solution of either sulphate, muriate or other suitable
salt of ammonia, and when this solution is thus charged with an excess of ammonia,
neutralizing the free ammonia by means of acid, and using the same solution over and
over again until it acquires a density of about forty degrees (Twaddell) or other
suitable strength which may then be evaporated to dryness leaving the ammoniacal
salts substantially as hereinbefore described.
Secondly We claim the general construction and arrangement of parts constituting
the improved apparatus for effecting such recovery substantially as hereinbefore
described and illustrated by the drawings annexed.
GEORGE DAVIES,
4, St. Ann's Square, Manchester,
Agent for the Applicants.