Improvements in the Method of and Means for Enriching Coal Gas:
Year: 1896

page_text: Date of Application, 6th Mar., 1896
Complete Specification Left, 15th July, 1896-Accepted; 15th Aug:; 1896
PROVISIONAL SPECIFICATION.
Improvements in the Method of and Means for Enriching
Coal Gas:
We, ROBERT GEORGE SHADBOLT, of The Gas Works, Grantham, Lincoln-
shire, Gas Engineer; and JOHN WILSON BROADHEAD, of the Firm of Robert
Dempster and Sons, Limited, of Elland, Yorkshire, Gas Engineers, do hereby
declare the nature of this invention to be as follows:-
This invention relates to a new method or means of enriching coal gas, and this
we propose to accomplish whilst the gas is being manufactured, and by the aid of
its own products.
In enriching gas according to our invention we convey a portion of the partly
purified gas 10 per cent., more or less, from say the scrubber, washer, or
exhauster outlet or at that point where the gas contains the lighter hydro carbon
or oil vapour after the removal of the heavy tars which are sent back again into
the condenser inlet or at any point determined by local considerations, inter-
mingling with the foul gas. Our object in returning the purified or partially
purified gas is to take up from the foul gas hydrocarbon vapours, which would
otherwise. be useless, and to utilise these vapours in absorbing and carrying
forward the heavier of the many constituents that may have been deposited. This
action of blending gas is based upon the well known affinity of marsh gas for
hydro carbon vapours and the absorbing power of light vapours for the heavier
illuminating constituents. Under certain conditions it may be advisable to bring
the temperature of the returning gas to about the same as that of the foul gas;
this may be regulated by means of a steam hot air jacket or other equivalent
means. By blending gases where one is in a higher state of manufacture that the
other, the illuminating power of the fully manufactured gas is greatly increased
and this is obtained without increasing the quality of the coal used in the
manufacture of the said gases.
Dated this 5th day of March 1896.
TASKER & CROSSLEY;
Halifax, Patent Agents.
Improvements in the Method of and Means for Enriching
Coal Gas.
We, ROBERT GEORGE SHADBOLT, of The Gas Works, Grantham, Lincoln-
shire, Gas Engineer, and JOHN WILSON BROADHEAD, of the Firm of Robert
Dempster and Sons, Limited, of Elland, Yorkshire, Gas Engineers, 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 a new means or method of enriching coal gas, and this
we propose to accomplish whilst the gas is being manufactured and by the aid of
its own products

page_text: It is well known that coal gas in the earlier stages of manufacture deposits in
the form of tar, oil, etc. the greater part of its heavy vapours; a small proportion
of which if retained would have a material effect upon the resultant illuminating
power of the gas; and we claim by our method to retain a portion of these
vapours, which, under ordinary treatment would be precipitated and absorbed in
the tar.
In enriching gas according to our invention, we convey a portion of the partly
purified gas ten per cent. more or less according to requirements-from a point
generally found between the exhauster and purifiers (as usually placed) that point
varying with local conditions. The place required is where the gas contains the
lighter hydro-carbon or oil vapours after the extraction of the tar, or in other
words where the gas contains the minimum of tar vapours with the maximum of
oil vapours.
From this point taking advantage of the difference in pressures here and at the
foul main if the point be after the exhauster a portion of the gas is returned to
another point generally found between the hydraulic main and the condensers,
the position of this point varying according to the quantity of gas being made
viz. :-
Under normal conditions and with the maximum make of gas, we should
introduce the returning gas somewhere about the condenser inlet; with a smaller
make of gas, at a point nearer the retorts, and with the minimum make of gas at a
point possibly half way or more back towards the retorts; taking care always that
all the tar extracted from the newly made gas be drained off previous to its
reaching this point; generally speaking the temperature of the gas here will be
between 100° and 130° F., although under normal conditions the best results are
obtained when the temperature is from 120° to 130° F. at the point where the
returned and newly made gases intermingle. We claim that the oil vapours
contained in the returned gas prevent the precipitation of a portion of the heavier
vapours still retained in the newly made gas which, if left to ordinary influences
would condense out and be deposited either as liquids or solids; these heavier
vapours being saturated or blended with the oil vapours of the returned gas, and
this being done in the presence of marsh gas, are carried forward away from the
condensing influence of vapours already become liquid and subsequently become
fixed in the finished gas.
Under certain conditions as extreme cold &c. it is sometimes advisable to
slightly raise the temperature of the returning gas, and when necessary we do this
by means of steam jackets, hot air jackets, or other equivalent means.
The returning gas is conducted by means of ordinary pipes properly fixed,
drained, &c., to a meter suitable in size and construction where it is duly measured
and conducted through one or more of the three or more branches to the point
selected as before mentioned.
When blending gases in different stages of manufacture as herein described, the
illuminating power of the fully manufactured or finished gas is greatly increased
without altering the quality of the coal used, or introducing any foreign enriching
agent whatever; or an inferior quality of coal may be used in many cases to
obtain gas of the ordinary illuminating power.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
The means or method herein described of enriching coal gas.
TASKER & CROSSLEY,
Halifax, Patent Agents.