IMPROVEMENTS IN PURIFYING ILLUMINATING GAS, AND IN TREATING THE PRODUCTS OBTAINED IN THE VARIOUS PROCESSES OF PURIFICATION
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by George Thomas Livesey at the
Office of the Commissioners of Patents, with his Petition, on the 26th
May 1862.
1. GEORGE THOMAS LIVESEY, of the South Metropolitan Gas Works, Old
Kent Road, in the County of Surrey, do hereby declare the nature of the
sand vention I IMPROVEMENTS IN PURIFYING ILLUMINATING GAS, AND IN
TREATING THE PRODUCTS OBTAINED IN THE VARIOUS PROCESSES OF PURIFICATION,"
to be as follows:-
One part of my Invention consists in purifying illuminating gas produced
by the distillation of coal from the impurities, such as ammonia and sulphu-
retted hydrogen, contained therein by means of sulphurous acid. The manner
of causing the sulphurous acid to act upon the gas, so as to make it combine
with and remove these impurities, may be variously modified. but, by pre-
ference, employ the following method: cause a solution of sulphurous
acid to pass in a downward direction through an ordinary scrubber" filled
with coke or other suitable material, through which the impure gas is passing
in an upward direction. The ammonia contained in the gas is by this means
made to combine with the sulphurous acid forming sulphite of ammonia,
which is carried down to the bottom of the scrubber into a tank or other
vessel for collecting the liquid. A portion of the sulphuretted hydrogen is

page_text: also decomposed by the sulphurous acid. the sulphur being precipitated and
collected in the tank at the bottom of the scrubber in any convenient manner.
then pass the gas up through a second scrubber, which is supplied only with
water at the top: this causes any sulphurous acid that may pass over with
the gas from the first scrubber to combine with the remaining sulphuretted
hydrogen contained in the gas, and the resulting solution may be conducted
into the same vessel as that containing the solution of the first scrubber; or
it may be conducted into a separate vessel. Should some of the sulphurous
acid be still contained in the gas after it leaves the second scrubber, I pass it
through a third scrubber, down which water is passed containing a little pure
ammonia, or some of the ammoniacal liquor from the condensers, and, if
requisite. afterwards pass the gas through a fourth scrubber with water only,
so as to remove the last traces of the ammonia introduced into the third
scrubber. which should be slightly in excess of the quantity necessary to
combine with the sulphurous acid coming with the gas from the second
scrubber. I do not, however, limit myself to the number of scrubbers herein-
before indicated, as I may employ a greater or less number, according to the
nature of the gas. In some cases instead of employing the last two above-
mentioned scrubbers i pass the gas after it leaves the second scrubber through
the ordinary lime purifiers to remove the remaining sulphurous acid. In
some cases first remove the ammonia by water or other known means,
and then apply the above-described process for removing the sulphuretted
hydrogen alone.
Another part of my Invention consists in converting the products resulting
from the before-described method of purifying the gas, as also the ammoniacal
liquor resulting from its previous purification by condensation into useful or
marketable substances. By the action of the sulphurous acid upon the sul-
phuretted hydrogen, as before described, sulphur is precipitated into the tank
of the scrubber in the state of powder, which has only to be removed, washed
and dried to be fit for market. The solution of sulphite of ammonia formed
in the scrubber, as before described, is first rendered of sufficient strength
by using it over and over again in the scrubbers, adding each time fresh
sulphurous acid to combine with more ammonia. When it is sufliciently
strong, expose the solution to the action of the atmosphere, so as to absorb
oxygen; or cause it to combine with oxygen in any convenient manner, by
which convert it into sulphate of ammonia in a more or less pure state,
which is then evaporated in the ordinary way, so as to obtain a marketable
salt. The crude ammoniacal liquor resulting from the purification by con-

page_text: densation is first converted by the admixture of sulphurous acid into sulphite
of ammonia, which is then converted into sulphate of ammonia, as above
described. The sulphuretted hydrogen contained in the liquor is also decom-
posed by the above process, and sulphur is deposited, which is removed, as
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