Improvements in Coal Gas and like Gases and in the Manufacture thereof.
Year: 1889

page_text: Date of Application, 14th Oct., 1889-Accepted, 30th Nov., 1889
COMPLETE SPECIFICATION.
Improvements in Coal Gas and like Gases and in the Manufacture
thereof.
I EDWIN TATHAM of Mullens Street Balmain near Sydney in the Colony of
New South Wales, Gas Engineer 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 :-
This invention relates to improvements in carburetted hydrogen gases and specially
in that kind commonly termed carburetted or bi-carburetted hydrogen or coal gas
and in hydro-carbon gases and to improvements in the manufacture of such gas or
gases from coal, shale, crude oils, tars, and such like and from other hydro-
carbonaceous substances and materials. Now this invention has been specially devised
with the following distinctive objects in view, first. to produce an improved explosive
Gas of a nature similar to that described and claimed in my application for Letters
Patent filed the 31st day of August one thousand eight hundred and eighty nine
and numbered 13763-secondly to improve the illuminating and heating power of
carburetted or bi-carburetted hydrogen or coal gas and hydro-carbon gas or vapours
and at the same time attain at a comparatively cheap cost a standard of purity
heretofore impossible, and thirdly to prevent or minimise the deposit of naptholine
and tar in gas works and pipes and to utilize tar and other deposited or residual
hydro-carbons by converting them into fixed illuminating and heating gas or gases.
The improvement in coal gas and like gases consists in the admixture with them in
reasonable quantity of oxygen and the improvement in the manufacture of such gases
and particularly in the manufacture of coal gas consists in the admixture of like
quantities of oxygen during the process of manufacturing of said coal gas and at
particular stages of such process. When I use the term ", oxygen" I would bave it
understood to mean oxygen either in a pure form or in the form known as commer-
cially pure and in both forms whether partially ozonised or not and further when the
words "reasonable quantity" are used they are to be understood to convey the idea
of such quantity of oxygen, or thereabouts, as will produce the best result attainable
in the direction desired and not to mean a comparatively very small quantity which
will only produce a somewhat similar result in a very much lesser degree.
In order that I may be clearly understood I will take an arbitrary standard for a
carburetted hydrogen or hydro carbon gases and point out in what quantity I would
add the oxygen. For example say I take as a standard gas containing say by bulk
two parts of hydrogen and six parts of carbon the after mentioned reasonable quantities
of oxygen are added and when the proportion of carbon, in the gas to be improved is
less than in said standard gas I would decrease the quantity of oxygen, bearing in
mind that, unless I wish to produce my said improved explosive gas, only just
sufficient oxygen is required as will combine or mingle with the whole of the carbon
in the gas to which it is added. To produce the said improved explosive gas I would
add to a Hydro-carbon gas or vapour of the standard before mentioned say from
seventy to one hundred and fifty per cent. by bulk of oxygen while to obtain the best
illuminating and heating results from a hydro carbon gas or vapour of the said
standard I would add say from thirty to sixty per cent. by bulk of oxygen and in no
case would I propose adding to carburetted or bi-carburetted hydrogen to improve it
for illuminating and heating purposes less than one per cent. by bulk of oxygen.
Where the object of the addition of oxygen is the improvement for illuminating and
heating purposes of the gas to which it is added, the addition may be made at any
stage of the manufacture of or processes to which the gas to be so improved may
be subjected subsequent to the carbonising of the material from which it is manu-
factured or during its storage as may be found most suitable.

page_text: I
In carrying out the improvement in the manufacture of coal gas and like gases
prefer to add the oxygen to the gas just after it leaves the retorts and has been
reduced in temperature below say three hundred degrees (300°) Fahrenheit and do so
by forcing the oxygen into the main conveying the gas from the retorts. In the
said main a chemical change takes place, the oxygen, having a chemical affinity for
the carbon (which at a later stage would otherwise be partly deposited in the form
of naptholine and other hydro-carbons) mingles or combines with the carbon leaving
any sulphur and like impurities free either to be easily absorbed by lime (through
which the combined gas so formed may be passed or with which it may be otherwise
treated) or to be deposited in the water in the gas holder. Where any tar or other
hydro-carbon is extracted or deposited in the process of gas manufacture or is to be
used in said manufacture I place the same in the retorts and there convert it into
hydro-carbon gas and vapour. The hydro-carbon gas and vapour so produced passing
from the retorts meets either in the main or in the gas holder with the oxygen which
as before mentioned mingles or combines with the carbon and the product is a fixed
gas of bigh illuminating and heating power.
In the cases above described (except in the manufacture of the explosive gas) and
in similar cases for the oxygen there might be substituted carburetted oxygen or
oxygen charged with hydrogen and carbon and it is to be noted that the admixture of
such carburetted oxygen with hydro carbon gas is described and claimed in an
application for Letters Patent by myself of even date herewith.
I would have it distinctly understood that I do not claim the admixture of a
comparatively small quantity of oxygen to coal gas to assist merely in the purification
of the same nor do I claim any of the admixtures described and claimed in my other
applications for Letters Patent hereinbefore mentioned.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed I declare that what I
claim is
First. The improvement in coal gas and like gases consisting in the admixture
therewith during or after manufacture of oxygen in reasonable quantity substantially
as herein described and explained.
Second. The improvement in the manufacture of coal gas and like gases consisting
in the admixture therewith during manufacture and preferably as they issue from
the retorts of oxygen in reasonable quantity substantially as herein described and
explained.
Third. The improvement in the manufacture of coal gas and like gases consisting in
converting the tar produced or other similar hydro carbons into gas or vapour which
is admixed preferably while still hot with oxygen substantially as herein described
and explained
Dated this Fourth day of September One thousand eight hundred and eighty-
EDWIN TATHAM.