IMPROVEMENTS IN THE PURIFICATION OF COAL GAS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Miles Williams at the Office of the
Commissioners of Patents on the 24th July 1883.
MILES WILLIAMS of Wigan in the County of Lancaster Varnish Manufacturer
"IMPROVEMENTS IN THE PURIFICATION OF COAL GAS"
The usual method of purifying Coal Gas is to force it through Oxide of Iron or
recently powdered lime until these substances become saturated with Sulphuretted
Hydrogen deposited by the impure Gas. The oxide of Iron if taken out of the
purifiers after having been so employed and exposed to the atmospheric air is acted
upon by the oxygen and reverts to its original condition and can be used again, while
the Sulphuretted Hydrgen [sic] which it has absorbed is released from the iron and
remains in the material as free sulphur in the form of a fine powder. In order
effectually to purify the gas the removal of the oxide from the purifyers is very
frequent and is attended with much labour and loss and is from the objectionable
smell of the sulphuretted hydrogen liable to be a great nuisance. In order to
obviate the necessity for such frequent changes atmospheric air has been used by
being drawn or forced along with the Coal Gas through the purifying materials so
as to super-oxidise or revivicate the oxide of iron but in practise the air thus drawn
or forced in although acting very beneficially upon the purifying materials dilutes
the Gas and lessens its illuminating power
This Invention has for its objects the supply of the necessary amount of
atmospheric air so as to revivify the oxide in the purifyers avoiding the necessity
for the frequent discharging and recharging and at the same time carburate such
air with the most suitable Hydrocarbon, such as Petroleum or Petroleum Spirit, or
Paraffin Oil, or Spirit. In this way the air is made to take up and carry into
the gas sufficient illuminating material to make good that which would otherwise
be lost through the introduction of air alone
The Invention consists in forcing or drawing the necessary quantity of atmospheric
air suitably heated or at the ordinary temperature through a gas Carburettie or
other suitable vessel charged Petroleum, Paraffin or other mineral oils, spirits or
their derivitives in fact any hydrocarbon other than Gas Tar or its derivitives
preferably employing petroleum spirit heated if necessary with a steam coil or
jacket or in any other convenient manner the carburetted air being delivered into

page_text: the main at any suitable point before the Gas reaches the purifyers. Coal tar or
Gas Tar or its derivitives are not applicable for the purposes of my Invention as if
Gas tar is used the air extracts all the light hydrocarbons or napthas and leaves
the great bulk of the tar practically valueless and Gas tar having been so employed
would therefore become a valueless instead of profitable to the Gas maker and by
using petroleum spirit or similar substances as the carburetting material better
results are obtained for the following amongst other reasons.
Petroleum and its derivitives are comparatively cheap, are always ready to hand
and all available for carburetting, leaving no residue, contain no sulphur or other
impurities likely to effect the Gas, are not like Gas Tar mixed with other
compounds (which form seven eights of its bulk) and are not valueable for
carburetting therefore by my Invention much labour is saved in handling the
carburetting material
By this Invention the carburetted air can be sent continuously through the
purifiers until the oxide becomes saturated with sulphur and useless, without the
labour and nuisance of frequently changing the oxide to expose it openly to the
air
The Petroleum spirit or similar compounds when generated into gas alone is the
purest gas that can be made and has moreover an illuminating power three times
greater than ordinary Coal.Gas so that when atmospheric air is forced or drawn
through this material in a suitable vessel it becomes charged with the hydrocarbon
and possesses illuminating properties