IMPROVEMENTS IN THE PURIFICATION OF GAS AND IN THE PREPARATION OF THE MATERIALS TO BE USED IN SUCH PURIFICATION
Year: 1882

page_text: LETTERS PATENT to George Careless Trewby of Beckton in the Counties of
Essex and Kent Gas Engineer-for an invention of "IMPROVEMENTS IN THE
PURIFICATION OF GAS AND IN THE PREPARATION OF THE MATERIALS TO BE
USED IN SUCH PURIFICATION."--A communication from abroad by Oluf
Andreas, Löwold Pihl of Christiania Norway Gas Engineer.
PROVISIONAL SPECIFICATION left by the said George Careless Trewby at
the Office of the Commissioners of Patents on the 10th March 1882.
"
GEORGE CARELESS TREWBY of Beckton in the Counties of Essex and Kent Gas
Engineer IMPROVEMENTS IN THE PURIFICATION OF GAS AND IN THE PREPARATION
OF THE MATERIALS TO BE USED IN SUCH PURIFICATION." A communication from
abroad by Oluf Andreas Löwold Pihl of Christiania Norway Gas Engineer
The principal object of this Invention is to effect the purification of Coal Gas in
closed vessels with a view to economy and the avoidance of any suisance.
The Gas after having been thoroughly condensed and deprived of its tarry
matter is passed into a scrubber or washer through which an acid or it may be
neutral solution of Sulphite, Sulphate, and Pentathionate of ammonia or their
equivalent is passed the result being that the ammonia is absorbed with a large
proportion of Sulphuretted hydrogen. The gas is then passed through a second
vessel in which caustic ammonia (made in any convenient way) is allowed to pass
by this means the carbonic acid wholly or partially arrested with some of the
sulphuretted hydrogen and the remaining sulphuretted hydrogen is carried forward
with the gas in the shape of hydro-sulphuret of Ammonia. The gas is now
admitted into a third vessel and treated with a similar acid solution as in the first
vessel by this means the sulphuretted hydrogen is reduced to the very minimum
and the after purification required is very small or the Gas may first be passed
through the scrubber of caustic ammonia and afterwards through the scrubber of
acid or neutral solution. The after purification can either be performed in the
ordinary way with oxide of iron and lime or by means of breeze or coke in a finely
CD...
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page_text: divided state or what is better the breeze or coke is saturated with a concentrated
solution of sulphate of iron and the material exposed to the action of red heat.
The passing of the gas through purifiers so charged deprives it of its last trace
of sulphuretted hydrogen and a purifier or purifiers of Lime after this removes the
last traces of carbonic acid. The advantages of this system are first that very
seldom will the breeze or coke have to be removed as it is only necessary from time
to time as the purifiers become charged with sulphuretted hydrogen to throw them
out and open a communication at the top and bottom of the purifiers with the
external air when a brisk oxidation commences and the material revivifies and can
be used in this way several times until the interstices become choked necessitating
the removal of the material. The lime is removed wholly as carbonate thus
avoiding any nuisance.
From time to time the saturated solution of Sulphate and Sulphite of Ammonia
or the like is run off from the scrubbers for evaporation and the requisite quantity
of liquor kept up by driving off the ammonia by a Coffey Still or any other con-
venient arrangement from the ammoniacal liquor formed in the condensers. The
liquid used in the acid solution scrubbers is kept either acidulated or neutral by the
introduction from time to time of Sulphurous acid.
In preparing the said solution a vessel is employed furnished with a furnace for
heating by means of a coke fire so that the solution is concentrated and at the same
time acidulated by sulphur from the coke aided if necessary by sulphur thrown
thereon. The vessel is provided at top with an outlet the heat below facilitating
the separation and driving off of impurities through this outlet. This outlet may
be led to a chimney for escape or to any place for the condensation or utilization
of the impurities.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Careless Trewby in the Great Seal Patent Office on the
9th September 1882.
"
GEORGE CARELESS TREWBY of Beckton in the Counties of Essex and Kent Gas
Engineer IMPROVEMENTS IN THE PURIFICATION OF GAS AND IN THE PREPARATION
OF THE MATERIALS TO BE USED IN SUCH PURIFICATION a communication from
abroad by Oluf Andreas Löwold Pihl of Christiana Norway Gas Engineer.
The principal object of this Invention is to effect the purification of Coal Gas
in closed vessels with a view to economy and the avoidance of any nuisance.
The gas after having been thoroughly condensed and deprived of its tarry
matter is passed into a scrubber or washer through which an acid or it may be
neutral solution of sulphite, sulphate and pentathionate of ammonia or their
equivalent is passed the result being that the ammonia is absorbed with a large
proportion of sulphuretted hydrogen-The gas is then passed through a second
vessel in which caustic ammonia (made in any convenient way) is allowed to pass,
by this means the Carbonic acid wholly or partially arrested with some of the
sulphuretted hydrogen and the remaining sulphuretted hydrogen is carried forward
with the gas in the shape of hydro-sulphuret of Ammonia and in this state can be
very readily decomposed in the third vessel it being essential to the success of the
process that the sulphuretted hydrogen should at first be absorbed by the Ammonia.
The gas is now admitted into a third vessel and treated with a similar solution
to that used in the first vessel by this means the sulphuretted hydrogen is reduced
to the very minimum and the after purification required is very small or the gas
may first be passed through the scrubber of caustic ammonia and afterwards
through the scrubber of acid or neutral solution or the gas may be passed first
the caustic ammonia scrubber and then through one or more dry scrubbers for the
purpose of separating the Hydro-sulpburet and Carbonate of ammonia and there-
after if found necessary the gas may be passed through the acid scrubber. The
after purification can either be performed in the ordinary way with oxide of iron or
lime or breeze or coke or other like porous material in a divided state (one or more
of them) or what is better the breeze or coke or the like is saturated with a solution
of sulphate of iron and the material exposed to the action of red heat after which
on cooling the material can if found necessary be washed with cold water to get rid
of any acid salts of iron that may be left or be sprinkled with crude ammoniacal
liquor to neutralize them.
The passing of the gas through purifiers so charged deprives it of its last trace
of sulphuretted hydrogen and a purifier or purifiers of Lime after this removes the
last traces of carbonic acid. The advantages of this system are first that very
seldom will the breeze or coke have to be removed as it is only necessary from time
to time as the purifiers become charged with sulphuretted hydrogen to throw them
out and open a communication at the top and bottom of the purifiers with the
external air when a brisk oxidation commences and the material revivifies
and can be used in this way several times until the interstices become choked
necessitating the removal of the material. The lime is removed wholly as carbonate
thus avoiding any nuisance. In the working of this process the gas will be admitted
at the top of the scrubbers or if washers are employed at the point where the fresh
Liquor is introduced so that the stream of gas flows in the same direction as the
scrubbing or washing liquor by which means neither sulphurous acid nor ammonia
is carried over from one vessel to another.
The saturated solution of sulphate and sulphite of ammonia or the like is run off

page_text: from the scrubbers or the store tank for evaporation and the requisite quantity of
liquor kept up by driving off the ammonia by a Coffey Still or any other convenient
arrangement from the ammoniacal liquor formed in the condensers The liquor
used in the acid solution scrubbers is kept either acidulated or neutral by the
introduction of sulphurous acid.
The sulphur with which the spent material is charged can be burnt out for the
purpose of furnishing sulphurous acid to be used in this process. The sulphur
which settles out of the sulphurous solution in the process of working can also be
used for the same purpose or if found more profitable it can be sold and sulphur in
spent oxide of iron or pyrites or any convenient form can be employed.
The caustic ammonia may be conveniently prepared by decomposing the fixed
salts of ammonia in the residue left in the Coffey Still after the volatile Ammonia
has been distilled over.
The following is a convenient way of preparing the acid solution. A vessel is
employed furnished with a furnace suitable for burning sulphur and in any of the
forms which it is considered desirable to use. The vessel is provided at top with
an outlet the heat below facilitating the separation and driving off of impurities
through this outlet. This outlet may be led to a chimney for escape and to produce
a vacuum or partial vacuum or to any place for the condensation or utilization of
the impurities.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is.
First The improvements in the purification of gas consisting in conducting the
process of purification as berein before described.
Second The process of preparing the acid solution for use in the said purification
process as hereinbefore described.
Third-The preparation and use for the purification of gas of breeze or coke or
like porous material saturated with a solution of sulphate of iron and subjected to
beat as herein before described.
In witness whereof I the said George Careless Trewby have to this my
Specification set my hand and seal the Seventh-day of September One
thousand eight hundred and eighty two.
G. C. TREWDI.
(87)