IMPROVEMENTS IN PURIFYING COAL GAS.
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said James Walker at the Office
of the Commissioners of Patents on the 31st March 1882,
JAMES WALKER of 10 Elmwood Place Leeds in the County of York
IMPROVEMENTS IN PURIFYING COAL GAS.
I take coke from which the gas has been extracted and I put it through a suitable
machine to crush it into a coarse grained sand, or I take the small dust of the coke
termed breeze (if clean and free from exteranious matter) and I screen it to the
I
proper size I require, and I crush up the larger lumps cast out of the screen
then impregnate this coke dust with hydrate oxide of iron to oxidize or mineralize
it by saturation in the manner following. I take a vessel or vessels of suitable
size for my intended operations and I put therein a quantity of old scrap iron, or
old scrap metal such as broken up gas mains or any other useless metal in equal
quantities, say two tons to fifty gallons of water or other suitable proportions, or I
use either iron scrap or cast metal seperately, but of sufficient quantity to make a
strong iron liquor, and as an alternative to make the oxidization of the iron more
rapidly I add a small quantity of muratic or sulphuric acids, or one of them, into
the vessels of the water and iron. I let this stand on the iron as long as possible,
I
say one to two weeks or upwards, the longer the better liquor for my purpose.
then decant the liquor off for use into a vessel or vessels, which I fill with as much
of the said crushed coke dust as can be conveniently immersed therein and I let
the coke remain in the iron liquor twenty four hours to one week or upwards, I then
draw the liquor off and return it into the iron vessels or I cast it away of no further
Or I spread the coke on the floor of a shed and sprinkle it with the iron
liquor till it is thoroughly wetted, then I turn it over into a heap so as to equalize
the moisture, in which state it may be left a few days, then spread on the floor
again and exposed to the air to dry till it is in a soft damp state.--I spread the
immersed coke to dry in the same way, for the same object-to bring it to a
use.

page_text: suitable condition for my next process, as follows.-I take hydrated lime in a finely
powdered state, say one part, and one part of the mineralized coke dust as above
described, and mix them well together, or I take one part of lime to two parts of
the mineralized coke dust mixed as aforesaid, or I mix one part of lime to three
parts of the said mineralized or oxidized coke dust, or other suitable proportions
for the work it has to do, but for ordinary general purification I prefer the first or
second named proportions, and I mix them into a thoroughly even equality one
with the other either by hand or by a suitable mixing machine and steam power.
I leave the mixture with sufficient moisture that it will adhere slightly together
when pressed in the hand, it is then ready for charging into the purifying boxes
now in use in all gas works, and I place it in the several layers of such thickness
each as is now done with lime when used for this purpose by itself, and to the
extent the box or boxes will allow to the depth of from two to four feet in each
box. The covers are then replaced and the gas turned on at the ordinary
pressure and in the every day way of working, till the charges become foul, as
with lime.
Or I fill one box in every four boxes of a set with the mineralized coke dust
only, or with the mixture of three coke to one lime to take up any tarry matter or
ammonia left in the gas in its previous operations, in which case when it becomes
foul to change, I replace it by other coke or the mixture of three coke to one lime
and I expose the outcast foul to the atmosphere for revivication turning it over from
time to time and spreading it on the floor of a shed and I re-wet it with the iron
liquor while thus exposed on the floor and dry it again to the damp moisture before
described when it is ready for reentery into the purifying box as at first, and I
repeat this as often as I think it will do purifying work. When finally filled up
with sulphur and other impurities it is ready for sale for the extraction of the
sulphur to make sulphuric acid.
By using this mineralized coke dust mixed with any of the proportions herein
stated of the hydrated lime to purify gas, I extract more impurities such as
bisulphide of carbon, ammonia, tarry matter, and sulphuretted hydrogen, than can
be extracted by lime only, and I can do more work with the same charge, that is,
pass more gas through the purifyer of as good or better quality in a given time
than when lime only is used by itself, because the mineralized coke being more
porous gives the gas more access to the lime offering thereby a larger surface for
the purifying action, and the mineralized coke takes out impurities that the lime of
itself cannot do. But the combined chemical action of the two substances give
results as above stated at a minimum of cost, as it is quite clear that by using one
moiety of the mineralized coke to one moiety of lime I save half the cost, (if all lime
were used,) now expended in purifying gas, and I utilize a waste product (the breeze)
made in all gas works in large quantities, at present sold for little or nothing to
get rid of it.
This provisional specification does not in any way, nor is it intended, to interfere
with the patent granted to me No 5269 dated Decr. 2nd 1881 for improvements in
purifying coal gas, nor with the provisional specification of my application No. 387
dated Jany. 26th 1882 for further Improvements in purifying coal gas for which
provisional protection has been granted to me. It is my intention to work all
three patents when completed seperately or in union one with the other, as
circumstances may permit or as occasion may require.

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 29th September
1882.
JAMES WALKER of 10 Elmwood Place Leeds in the County of York.
IMPROVEMENTS IN PURIFYING COAL GAS."
According to my said Invention I take Coke from which the gas has been
extracted in a dry or semi dry state or the small coke and dust from the Coke
heaps called breeze or the Retort breeze that is to say the breeze which falls from the
Retort fire bars if they have been fed with ordinary gas coal (but not if it consists
of Cannel ashes only) but I may employ any other Coke breeze made at Gasworks.
I pick out or separate the large Clinkers and then pass the said Coke or breeze
through a disintegrator or say for example a revolving grinding pan having a
perforated bottom of a mesh of holes through which the Coke or breeze can
escape as it is ground without causing it to, be ground too fine. I require the
size of the grains to be about that of ordinary river sand or Saw dust. It is
then ready for my next operation, to be mineralized or impregnated with hydrate
Oxide of Iron and for this purpose I prepare "iron water in the following
manner--I take a vessel or vessels in size and number in proportion to the
quantity of iron water I require and I put into each vessel a quantity of old scrap
iron or metal of any otherwise useless sort such as broken up gas mains say about
two tons to fifty gallons of water I use either one kind of metal or two or more
together I then fill up the vessel or vessels with water and I let the water
stand on the iron on the first immersion preferably about one week or upwards
the longer time the better for my purpose. I then draw or pass off the water
into other vessels in which I place as much of the ground Coke or breeze from
the grinding pan or disintegrator aforesaid as the iron water will immerse and
the vessels will hold I stir the iron water and ground material well together
as the breeze is put into the iron water and I let the ground Coke or breeze
remain in the iron water preferably about twenty four hours or upwards till it is
thoroughly saturated with the said Iron water. I then draw off the surplus
water from the Coke or breeze-I let the Coke or breeze drain and dry to a soft
moist state it is then ready for my next process.
Should any Gas Works have on their premises or convenient thereto a natural
Chalybeate water that contains a sufficient amount of hydrate Oxide of Iron I can
utilize it for the purpose of mineralizing the Coke or breeze dust instead of making
the above described iron water as aforesaid and it only requires to be pumped or
run by gravitation into tanks or cisterns containing the Coke or breeze dust I let
water run on to it for preferably from twenty four to forty eight hours more or
less, I place at the bottom of the tanks or cisterns an outlet pipe to carry off
the water after passing through the Coke or breeze which will emerge therefrom a
pure useful water having left its Oxide of Iron in the Coke or breeze dust which
will then be sufficiently mineralized (by the passing of the water as aforesaid) to
be ready for removal from the Tanks or Cisterns to be drained or dried to the state
required I then refill the tanks or Cisterns with other ground coke or breeze and
repeat the same process and so on from time to time as fast as the ground coke or
breeze aforesaid becomes sufficiently mineralized by the iron water passing through
it. When the ground Coke or breeze appears of a rusty colour in the tanks or
cisterns it is then fully charged with the oxide of Iron requisite for my purpose
and may be at once removed and a quantity of fresh ground Coke or breeze be
treated as aforesaid. I dry the mineralized ground Coke or breeze thus discharged,

page_text: to the moist state as hereinafter described and it is then ready for the next process
as follows:-
1
I take hydrate of lime in powder one part by measure or weight to an equal part
(or any other suitable proportion) of the mineralized ground coke or breeze and
mix them intimately together by hand or machine and the mixture may then be
placed in the purifying boxes for immediate work in purifying the gas. Or I
take the ground coke or breeze or the Retort breeze from the grinding pan
or disintegrator without having it mineralized as above described-one part by
weight or measure and one part of Hydrate of Lime or any other suitable proportion
more or less and I mix them intimately together either by hand or machine as
aforesaid in a moist condition (not wet). The mixture may then be placed in the
purifying boxes in manner hereinafter described and it is then ready for the gas
being turned on in the usual way and at the normal pressure of the gas made.
Or I prepare the ground coke or breeze and lime differently in the manner
following which I prefer that is to say, I saturate, the Coke or brecze or Retort
breeze in its rough unground state in the iron water prepared from the old Iron or
metal as above described or in the natural Chalybeate water containing the Hydrate
Oxide of Iron aforesaid or if the said Coke or breeze be used without being
mineralized saturated in water only. In either case that is, whether saturated
with water only or with iron water I place one part of the Coke or breeze by
measure in its wet state in the grinding pan or disintegrator aforesaid and at the
same moment I add one equal part by measure or other suitable proportion of quick
or unslacked lime in lumps as received from the Kiln and I grind the two materials
together preferably to the size of River Sand as aforesaid and they become thoroughly
mixed together while in the grinding pan or if not well mixed on being discharged
from the grinding pan I cause the matter to pass into a mixing machine which
completes the operation without any other labour than filling the pan and casting
the mixed materials into a heap ready for use in the purifying Boxes.-If the Coke
or breeze be not wet enough to cause the Lime to fall into a hydrate powder
sufficient water or iron water may be dropped into the grinding pan while in
operation to slack the Lime which I leave in the heap for preferably about twenty
four hours for that purpose.-I require the mixed coke or breeze dust and lime thus
prepared to be in such a moist state when placed in the purifying boxes that when
it is pressed in the hand it will slightly adhere in a ball, then it is in a proper state
for immediately passing the gas through at the ordinary pressure. I have named
one equal part of the ground Coke or breeze to be added to one equal part of Lime
mixed in the Hydrate state or quick lime ground from the kiln with the Coke or
breeze as above stated in the revolving pan or disintegrator but I give these
quantities as approximate only and as an example of one proportion of the ingredients
which will do good purifying work; but any other proportions of lime and ground
Coke or breeze may be used whether the Coke or breeze dust is mineralized as
above or used without being mineralized for example one part of Coke or breeze
dust to three parts of Lime whether hydrate or ground from the quick lime or one
part of coke or breeze dust and two parts of lime as aforesaid or any other suitable
proportions as the nature of the work to be done requires that is if much gas is
wanted to be passed through the Purifiers quickly then use more Breeze and less
Lime. When the two mixed materials are prepared I fill the purifying boxes in
layers in the usual way to the total thickness of the several layers in one box of
three to four feet or to the capacity of the depth of the boxes under operation more
or less and I cause each layer to be pressed or rolled on its surface and the sides of
the boxes to be pressed so as to solidify to a moderate extent the layers and if the.
materials of the charge consist of more coke or breeze dust than lime, a heavier
pressure or rolling on the surface is required than when more line is used than
breeze in the mixture because the Coke or breeze dust being lighter requires more
weight to effect the same object, namely the partially solidifying of the layers so
that the gas shall not pass too rapidly through the charge and carry the impurities
along with it. To each set of four purifying boxes I prefer to have three constantly

page_text: in working operation while one fouled is being changed I fill each box with the
mixed materials Coke or breeze dust and line as above described whichever
proportions of Coke or breeze dust and lime may be used and in the aggregate of
the set I calculate the gas to pass through twelve to sixteen feet of thickness of the
charge as if the lime by itself or oxide of iron were used to purify with.
Or I charge the first purifying box of each set of four boxes and if necessary the
second box also with mineralized Coke or breeze dust only in layers as above
stated to the total thickness in one box of three to four feet or upwards or the
depth or capacity of the box more or less to catch or extract any tarry matter or
Ammonia that may have escaped with the gas in its previous processes. The two
or three remaining purifying boxes of the set I charge with one or other of the
above named mixtures of line and coke or breeze dust as hereinbefore described.
I cause each layer of the mineralized coke or breeze dust to be well rolled or pressed
so that the gas shall not pass too rapidly through the charge as before stated:
When the charge of mineralized coke or breeze dust becomes fouled in the box I
replace it with other mineralized Coke or breeze dust and I expose the fouled
matter discharged from the boxes to the atmosphere for revivification after which
it will then be capable of being again employed in purifying when again placed
in the purifying boxes and so on in succession from time to time till it is fully
charged with sulphur and other impurities. It may be taken to be fully charged
when it contains forty to fifty per cent of Sulphur and can then be sold for the
recovery of the Sulphur for making Sulphuric Acid in the usual way. The
Ammonia can be extracted by immersing the discharged breeze in water for
such a time as it may require and added to the regular Ammoniacal liquor
for sale.
By grinding the lime from the Kiln with the Coke or Breeze as above stated I
save the cost and labour of slacking to make a hydrate of Lime and the cost of
mixing the Coke or breeze dust and lime together as the machinery performs both
operations at the same time.
I keep up my stock of Iron water other than Chalybeate water aforesaid for
any sized works by using tanks or cisterns of sufficient capacity say old or
superseded purifying boxes or old steam boilers or wooden cisterns and the same
for saturating the ground Coke or breeze dust in the iron water and so often as I
draw off the iron water from the breeze I add fresh water into the tanks so that
my supply of iron water will not fail and I add more iron from time to time as
the other wastes away in the water; and if I require a rapid oxidation I add a
suitable proportion of Muriatic or Sulphuric Acid into the water in the tanks but
if time be given the Acid is not necessary. Or if the natural Chaly beate water be
used to mineralize the Coke or breeze dust these tanks will hold the breeze for the
purpose as above described.-The Coke or breeze dust whether mineralized as
herein stated or not being mixed so intimately with the lime, hydrate or ground
from the kiln makes the lime in the purifying boxes open and porous and gives
thereby a greater surface of lime for the attraction and the purifying action of the
gas and the gas passes through the layers of Coke or breeze dust and limo more
easily and the Coke or breeze dust prevents the lime giving pressure or back
pressure against the passage of the gas its purifying action is thereby enlarged and
the Coke or breeze dust filters absorbs and retains impurities from the gas that
lime of itself will not take up and I require no auxilliary material or substanco
than this mixture of ground coke or breeze dust and lime whether mineralized or
not to procure a good gas.
I anticipate a saving of gas by the use of mixed breeze and lime as all gas made
by the Retorts will pass casily through the purifiers charged with this mixture of
lime and breeze. I utilize the breeze and Retort breeze which is mostly of little
value and which all gas Works make in large quantities and at a great number of
Works are often unable to sell it at any price worth notice. 1 save half the cost
of Lime when I use equal parts of lime and Coke or breeze dust or its proportionate
cost when more or less of the Coke dust is used in the mixture. When the charges

page_text: of mixed lime and coke or breeze dust have become finally fouled by having done
the purifying work on the gas it may be used as a fertilizing manure on land of
for incorporating into stiff clay for bricks and for fuel to assist in burning bricks ir
spread in layers between the walls of bricks in the kilo, or for burning other lime
in suitable kilns.
Or if the lime be reburned for revivification as is now done in some of the gas
works in England, the Coke or breeze dust mixed in the lime will greatly assist
the operation and the ashes of the Coke or breeze dust left in the lime when
reburnt will be of use in its next purifying action when again placed in the
purifying boxes.
Having now fully described the nature of my Invention and the manner in
which the same is to be performed or practically carried into effect I wish it to be
understood that what I consider to be novel and original and therefore claim as the
Invention secured to me by the herebefore in part recited Letters Patent is :-
Purifying coal gas as herein before stated by using the waste product called
breeze Retort breeze mineralized or without being mineralized ground and mixed
as aforesaid with Hydrate of Lime or ground quick lime from the kiln in the
manner and for the purpose substantially as herinbefore described.
In witness whereof I the said James Walker have to this my Specification set
my hand and seal this Twenty third day of September One thousand eight
hundred and eighty two.