IMPROVEMENTS IN PURIFYING COAL GAS
Year: 1882

page_text: LETTERS PATENT to James Walker, of 10, Elmwood Place, Leeds, in the
County of York, for an Invention of "IMPROVEMENTS IN PURIFYING COAL
GAS," being an enlargement or extension of the Invention secured to him by
Letters Patent dated 2nd December 1881, No. 5269.
PROVISIONAL SPECIFICATION left by the said James Walker at the Office
of the Commissioners of Patents on the 26th January 1882,
JAMES WALKER of 10 Elmwood Place Leeds in the County of York. IMPROVE-
MENTS IN PURIFYING COAL GAS. Being an enlargement or extension of the
Invention secured to me by Letters Patent dated December 2nd 1881 No. 5269.
I take coke from which the gas has been extracted in a dry or semi dry state as
slacked from the retorts, and I put it through a suitable machine to crush into bits
the size of a pea together with the amall made in crushing as described in my
Provisional Specification of my aforesaid Patent. I then impregnate the crushed
coke prepared as above with the hydrate oxide of iron, to mineralize it in the
manner following.
I take a vessel or vessels of size or sizes in proportion to the extent of my
intended operation and I put into them a quantity, say two tons, to fifty gallons of
water or other proportions, of old scrap wrought iron of any kind, and old cast
metal scrap, such as broken up gas mains, or any other useless metal, in equal parts
to each vessel in the proportions above stated or any other suitable proportions, or
I use one or the other separately but sufficient to make a strong oxidized or
mineralized liquor, I let the water stand on the iron twenty four hours to one week
or upwards, the longer the better liquor, after that, I decant the liquor off the iron
into an empty vessel or vessels, which I fill with as much crushed coke as the
liquor will immerse and I let the coke remain in the liquor from twenty four hours
to one week or upwards. I then draw off the liquor and return it to its former
vessel or vessels or I cast it away of no further value.
After draining, the saturated coke is ready for placing in the purifying boxes

page_text: while in its damp state, and I place it therein either in one, two, three or four
layers not exceeding two feet in thickness, or according to the depth of the puri-
fying boxes then under operation. When the purifyers are thus charged the covers
are replaced and the gas turned on at the usual pressure and continued as to the
time it should pass from one end of the set of purifyers to the other end before its
reversal to enter at the end it had come out purified, at the discretion of the
engineer or superintendent in charge of the works, on seeing the nature of the
purifying work it is doing. And also after its reversed passage, the time for its
discharge out of the box for revivication by exposure to the atmosphere in the
usual way. After this exposure, if dry, I re-wet the coke to its original dampness
with the oxidised water as it is being stored up under a roof, when it is then ready
for a second or other course in the purifyers till it is fully charged with sulphur
and other impurities as described hereafter.
I keep up the stock of oxidized or mineralized water by refilling the vessel or
vessels as fast as I draw off the liquor keeping them always full of water, and from
time to time I add fresh iron as the old wastes away in the water so I keep the
strength of my liquor as equal as I can before its use on the coke.
In the passage of the gas through the purifying boxes as above described, the
mineralized coke by its angularity porocity and affinity, filters, absorbes, and
retains the sulphur and other impurities which the gas contained when it entered
into the purifying boxes.
When it is ascertained the coke has absorbed, say forty to fifty per cent. of sulphur
or thereabouts it may be taken as fully charged and incapable of doing much more
profitable work in purifying and may be cast out and replaced by fresh or other
coke as before and so on continuously without further trouble than using the
ordinary labour.
The coke.is then ready for sale or use for the extraction of the ammonia it contains,
and the sulphur for making sulphuric acid, in the usual way.
By using this mineralized coke to purify coal gas I obtain a better gas, more
pure, giving a greater illuminating power than is obtained by any other materi :ls
now used for that purpose, 1 extract more sulphur, ainmonia and other impurities,
I also save the sulphur and ammonia both valuable products which are entirely lost
when lime is used in purifying. I save the carriage and cost of other materials as
all gas works have what I use on hand, and utilize them at minimum of cost which
is a most important consideration in the economy of manufacturing gas, I also
make the coke a more profitable article and increase its consumption value and
sale by making it the vehicle for the absorbtion of the sulphur and ammonia. The
material variation of this Specification with my aforesaid Patent is, mineralizing or
oxidizing the coke before it enters the purifying boxes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Walker in the Great Seal Patent Office on the 26th July
1882.
JAMES WALKER of 10 Elmwood Place Leeds in the County of York. IMPROVE-
MENTS IN PURIFYING COAL GAS being an enlargement or extension of the.
Invention secured to me by Letters Patent dated December 2nd 1881 No. 5269.
I take coke from which the gas has been extracted or the small from the coke
heaps called breeze, or the breeze which falls from under the retort fire bars
generally called pan breeze first screening out the ashes and largest clinkers and I
put the coke or breeze into a suitable machine such as a disintegrator pulveriser or
a revolving grinding pan with perforated bottom having holes of sufficient mesh to
allow the coke or breeze to escape without being ground to small about the size of
river sand or of ordinary saw dust I then take the ground coke or breeze and
impregnate it with the soluble hydrated oxide of iron by immersion in any natural
Chalybeate water or iron water prepared in the manner following. I take a tank or
tanks of the size required by my intended operations and I put into these tanks a
quantity of old scrap iron or cast metal using about two tons to fifty gallons of
water the proportions being sufficient to make a strong iron water let the water
remain on the iron on first introduction one week or upwards the longer the better
liquor I then decant the water off the iron into other empty tanks or cisterns and
place in such last named tanks as much of the ground coke or breeze as the iron water
will conveniently saturate or the tank will hold stirring them together as the coke
or breeze is added I allow the coke or breeze to remain in the iron water twenty four
hours or upwards till thorougly saturated and then cast it out to get rid of the
superflous water until the mixture arrives at the soft moist condition required for
my next operation the refuse water is thrown away as of no further use.
In the case of gas works possessing natural sources of chalybeate water available
this water may be utilised for the purposes of my Invention by simply conveying
it on to the coke or breeze in the tanks or cisterns for immersion as above
described in the iron water which will equally impregnate the coke or breeze
with iron for my purpose.
When the coke or breeze is after this operation
withdrawn and dried to such a condition of moisture as to remain adherent
in a ball or lamp when pressed in the hand it is ready for the purifyers
to be placed therein in layers in the usual way, each layer of this material may be
pressed at the sides of the boxes and rolled with a moderate sized roller so as to
somewhat solidify the charge so that the gas shall not pass too rapidly through it
without leaving its impurities behind In a set of four purifying boxes I charge the
first and second or one of them with the mineralized coke or breeze placed in
layers in the usual way to the full capacity of the box or boxes and pressed as
above stated and the remaining boxes of the set I fill with the mixture of hydrate
of lime and the ground coke or breeze whether mineralized or not in the same
proportions and manner as already specified in the Specification of Letters Patent
granted to me dated December second One thousand eight hundred and eighty one
Number 5269. I take one part of the mineralized coke or breeze to one part of
hydrate of lime or the proportion of lime may be increased to two parts or to three
parts or even more to one of coke or breeze and I mix them intimately together
in the condition for purifying before mentioned the mixture is then ready for the
purifyers placed in layers as aforesaid I prefer this mixture of lime and mineralized
coke or breeze to follow the purifyers charged with the mineralized breeze only in
preference to using lime by itself as hereinafter described Or I fill all the boxes of

page_text: the set with this mixture of hydrate of lime and mineralized coke or breeze as in
manner stated according to the nature of the purifying work required to be done
The gas may then be turned on at the regular every day working pressure.
When the mineralized coke or breeze used in the purifiers by itself becomes
fouled by the sulphur and other impurities extracted by the passage of the gas it
can be revivified by exposure to the air and after such revivification it is ready for
further work on being again replaced in the purifying boxes till it contains 40 to
50 per cent of sulphur when it may be sold for the recovery of sulphur and
ammonia.
In preparing the iron water as aforesaid I keep up the stock on hand for daily
use by turning on fresh water as often as I draw off the iron water and from time
to time I add other old scrap iron so that I have always a stock of iron water on
hand for immediate use for immersing the coke or breeze when required and I use
the chalybeato water when available exactly in the same way.
The gas in passing through the purifiers filled with the mineralized coke or
breeze and then through the others filled with the mixed mineralized coke or breeze
and hydrate of lime or either of them is by the action of the coke or breezo filtered
the sulphur ammonia tarry matter and other impurities which the gas contained on
its entry are retained in the purifying boxes which lime when used by itself will
not separate these impurities from the gas I therefore do more work that is I can
pass more gas through the purifyers in a given time than by the use of any other
material in purifying gas whether I use one or other or both of the preparations
herein described The mixture of lime and coke or breeze gives no pressure or
back pressure to the gas as lime does when used by itself and whether I use one
or two purifyers of the mineralized coke or breeze of the set or all the set of mixed
lime and coke or breeze as aforesaid I turn out a better gas of greater illuminating
power freer-from-impurities-than-is obtained by the use of lime by itself or oxide
of iron. Another advantage arising from my Invention is the utilization of the coke
or breeze upon the spot.
Having now described and particularly ascertained the nature of my 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 herein before in part
recited Letters Patent is :-
First Effecting the purification of coal gas by the employment and use of ground
coke or breeze impregnated with or made to contain compounds of iron when in a
state of division substantially in the manner and for the purposes hereinbefore
mentioned.
Second Effecting the purification of coal gas by the employment and use of
ground coke or breeze impregnated with or made to contain compounds of iron
the same being employed in conjunction with hydrate of lime substantially in the
manner herein before mentioned.
In witness whereof I the said James Walker have to this my Specification
set my hand and seal this twenty fourth day of July One thousand eight
hundred and eighty-two