Improvements in Methods of Generating Gaseous Fuel and in Apparatus therefor.
Year: 1886

page_text: Date of Application, 30th. Nov., 1886.
Complete Left, 17th Aug., 1887.
Complete Accepted, 20th Sept., 1887.
PROVISIONAL SPECIFICATION.
Improvements in Methods of Generating Gaseous Fuel and in
Apparatus therefor.
I, BENJAMIN HOWARTH THWAITE of 37 Victoria Street Liverpool in the County of
Lancaster Civil Engineer do hereby declare the nature of this invention to be as
follows:-
My present Invention relates to methods of generating gaseous fuel and in
apparatus therefor partly improvements on my former Inventions for which Letters
Patent have been granted to me numbered 16328 A.D. 1884 and No. 4 A.D. 1885.
The essential features of my present Invention are described in the following pages.
I provide two or more vessels preferably cylindrical in plan, but they may be square
or rectangular the upper half of these vessels I utilise for the accumulation of the
carbonaceous solid fuel, which I partially convert into combustible gases in a manner
hereafter described. The lower half of said vessel, I utilise for the accumulation or
storage of the sensible heat of the gases generated in the upper chamber, and for the
purpose of increasing the temperature of the atmospheric air or steam that I may
desire to use for the purpose of revivifying or blowing up of the carbonaceous fuel.
The lower half of vessel I term the recuperator chamber, the upper half I designate
as the gas generator chamber.
The entire vessel is preferably covered with a casing of light sheet-iron.
The gas generator is fed with fuel by means of a central feed hopper.
The sides of gas generator I construct of thick refractory material which I prefer to
construct with its internal face slightly inclined from the vertical. The upper part of
said refractory lining I may support upon the internal projection of an iron water
belt, the underside of projection of said belt I also protect with refractory material.
This internal projecting water belt forms a circular cavity for the accumulation of
the fused clinker ash and other residuum, and allows the air or the steam blast from
recuperator chamber to pass into the centre and around the carbonaceous fuel.
The clinker and ash are prevented from falling into the air blast cavities by means
of circular guard walls.
doans for the ramovat of the clinker

page_text: The recuperator chamber roof which forms the floor of gas generator I strongly
construct of refractory material and 1 adopt a novel method of providing heating
surface, and heat, accumulating capacity in recuperator chambers, by means of annular
cavities surrounding one central flue, between this inner flue and the outer annular
one by which the air blast enters into the fuel in upper gas generator chamber 1
provide radiating and corrugated walls formed of specially constructed firebrick tiles
which placed endways divide the annular space into numerous divisions, by which the
heat transmission action is effectually accomplished and which unlike checker
brickwork permits the dust and tar to be removed with very little trouble.
The lower end of central recuperator flue dips into a circular cavity which may be
filled with water so as to form a hydraulic scal, and assist in the removal of the far.
When I desire to remove the clinker or other residuum of the carbonaceous fuel in
a liquid form by the addition of a fluxing agent to the fuel, I prefer to construct the
gas generator chamber iron casing of an inverted cone shape similar in form to a
German cupola and I surround this casing with an annular water belt, the inclined
side of the vessel will allow a thin lining of magnesite, dolomitic lining, mixed with
anhydrous tar, or other equally basic and refractory material to be used. "I incline the
floor of such gas generator in such a way that the fluid clinker runs into a cavity
specially constructed near the clinker door.
I provide an upper platform two feet or thereabouts below the level of floor of gas
generator, or this floor may be the ground floor level and the recuperator half of vessel
be built below.
At the upper end of, and outside gas generator chamber I provide an encircling
steam pipe provided with branch pipes leading into an annular space between
brickwork of lining and iron casing, by which the steam enters over and into the
incandescent fuel.
I prefer to have at least three vessels working together, each vessel connected
together by means of tubular connections and valves, one between each gas generator
chamber, and another between the recuperator chamber.
I provide for the lower connections between recuperator chambers one three way
reversing valve of sliding mushroom, or any other pattern and on each side thereof a
stop valve. When three vessels are built I prefer to arrange them triangularly in
respect to each other in plan.
The cycle of my invention just described is as follows.
The fuel having been fed into the gas generator chamber to the height of at least
3 feet, I turn on the air blast which passes through the recuperator chamber and then
ascends the annular cavity connecting recuperator chamber with gas generator
chamber, into the fuel, which soon attains the necessary temperature for gasification,
the oxygen of the air in passing through the fuel, forms in combination with the
latter CO₂, which in passing through layers of incandescent fuel is converted into CO
and along with the volatile hydrocarbons and any CO, not converted, passes through
the upper connection into the gas generator Chamber of other vessel, the CO, in
passing descensionally through the incandescent fuel in this generator is converted
into CO, and the volatile hydrocarbons are converted into permanent gases, the gases
escape through annular cavity into recuperator chamber where they transmit their
sensible heat to the brickwork.
The valves are now reversed and the air blast is directed into the recuperator
chamber that has been highly heated by the passage of the heated gases through it.
The air blast passes ascensionally through the fuel, and the gases resulting
therefrom pass over, into the gas generator chamber of other vessel, the fuel in
this latter chamber being now brightly incandescent, the gases are
now further
hygenated in passing descensionally through the fuel-by the addition of a supply of
steam, from the steam supply pipes already described, the steam is highly superheated
in passing through the cavities, and in contact with the incandescent carbon, the
action is
and enriches the
4 H₂O + C = 4 H + CO2 + C = 4 H + 200
11

page_text: permanent nature-the sensible heat of the gases is accumulated in recuperator
chambers, and the gases so cooled, are distributed to the gas distributing mains.
When one of the vessels requires renewing the stop valves in connections are
lowered, and those of the other vessels are opened so that two of the vessels are
always in action.
Instead of the annular water belt projection around gas generator, I may have
simple vertical walls, and lead the air blast as it ascends from recuperator chamber
into a hollow wall in the centre of gas generator. When I desire to increase the thermic
value of the gases generated, I inject liquid hydrocarbons into the carbonaceous fuel
when incandescent-Substantially in the manner described in the patent granted to
me and numbered 16382 A.D. 1884 or I inject or allow the liquid hydrocarbon,
to fall either by gravity or under a liquid head pressure in special cavities
formed in side walls to allow the oil to be fed regularly I provide needle
feed valves working in the oil supply main-the liquid hydrocarbon falls drop after
drop into the cavities and is deflected on to the heated surfaces of the
walls by means of curtains or by projections built in side walls-the gases resulting
from the volatilization of the liquid hydrocarbon enters the solid carbonaceous fuel in
gas generator chamber through openings in walls at the lower end of cavities, or I
may lead the gas into a vertical iron or clay retort placed in the centre of gas
generator chamber, or forming part of the walls thereof, or I may use, to produce the
heat necessary to volatilize the gas, the combustion of the liquid hydrocarbon to heat-
up to a temperature necessary for volatilization-a nest of checker brickwork—the
products of combustion of the liquid hydrocarbon may be allowed to mix with the
volatilised hydrocarbon which is allowed to drop on to the heated checkerwork. Or I
may separate the gases of products of liquid hydrocarbon from that volatilized by
alternately heating the checker brick work and then feeding the fluid hydrocarbon to
be volatilized on to the checker work as long as the latter retains sufficient heat to
volatilize the fluid hydrocarbon, and to easily ascertain this, I provide mica covered
sight holes and delicate gas pressure gauges fixed on side of vessel. To avoid the
possibility of dangerous pressures being produced by an explosive mixture of gas
and air, provide a simple weighted safety valve fixed where required on the side of
the vessels. In a simpler form of my invention I divide one gas generator into two
equal parts by means of a hollow division wall somewhat similar to my patent
No. 4, 1885 and having a gas delivery opening at the upper part and with or without
the recuperator chamers which if used, would also be divided by said division hollow
wall but in this modification I prefer not to use recuperator chambers.
i
At the lower end of hollow part of central division wall I provide openings into the
gas generator on each side, but at the intersection of the side openings, into central
hollow space, I fix a reversing valve similar to the butterfly type used for Siemen's
furnaces. lead the air for revivifying the carbonaceous fuel through numerous
pipes or channels built horizontally under or forming the floors of the gas generator
and connecting the out side air with the bottom of hollow central space in division
wall by reversing the butterfly valve the air can be directed into either one or the
other gas generating chambers. To produce a flow of air and gases I use instead of
the pleuum the exhaust system, I effect this by a novel expedient, at the upper end of
gas generator chambers I provide centrally fixed a horizontal passage from outside to
outside through the two gas generator chamber side walls and through the central
wall-each passage being directly opposite to the other-so that a steam jet placed in the
centre of one side passage, would when the steam pressure was applied, exhaust all the
gas generated in the first chamber over which the flow of steam crossed, aspiring the
air through the air supply tubes forming the floor of the gas generator, and into and
through the carbonaceous fuel until the latter was thoroughly revivified, then a steam
jet placed at the opposite side passage to the other is turned on and that of the latter
turned off. I form the exhaust ducts or passages of fireclay and the central wall and
side walls at the part where the steam jet exhaust passage is formed considerably
thicker in section-so as to give a greater length of passage-the central exhaust passage
or the one through the central wall I taper from both ends inwards so as to produce

page_text: an exhaustive effect the gases thus drawn from one gas generator chamber through
the central passage are forced descensionally through the carbonaceous fuel in the
next gas generator chamber and escape into the opening leading through the central
butterfly valve, into the hollow opening in central wall to the outlet main or flue at
the upper end-by simply reversing the butterfly valve and the steam exhaust jets, the
direction of the currents of gases can be changed, as will be seen.
When the gases are required for heating magnesian filaments for illuminating
purposes or for gas motor purposes or for other purposes when clean gas is a
desideratum I adopt the following condensing arrangement, I construct a rectangular
chamber through which I cause the gases produced to traverse with water jacketted
sides and with numerous bafflers, so arranged as to bring the gases passing through
the condenser into continual contact with the side surfaces of the condenser without
unnecessarily impeding the flow of the gases. I form the sides of, and bafflers of the
condenser with corrugated sheet iron. I maintain a continuous circulation of water
through the sides and bafflers of condensers.

page_text: 1 BENJAMIN HOWARTH THWAITE of 37 Victoria Street Liverpool in the County of
Lancaster Civil 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
-
My present Invention relates to methods of generating gaseous fuel and in
apparatus therefor, partly improvements on my former Inventions for which letters
patent have been granted to me number 16328 A.D. 1884. and number 4. A.D. 1885.
I will now proceed to describe the five sheets of drawings that are intended to
accompany and form part of this specification.
I wish it to be clearly understood however, that I do not wish to be confined to the
exact details herein shewn-as it will be evident that they can be modified without
departing from the nature of my Invention.
Referring to sheet. 1 of drawings shewing one form of my Invention.
Figure 1 is a vertical section. Figure 2 is a part elevation and section through
connecting mains.
Figure 3 is a side elevation and Figure 4 is a plan in section through Recuperator
Chambers.
Figure 5 is a plan in section taken at the clinker door level.
Figure 6 is a plan in section at the level of upper connections.
Figure 7 shews a triangular plan arrangement of three gas generator or gas
producer vessels.
A is the gas generator chamber B the recuperator chamber constructed directly
under the gas generator A.
The Recuperator chambers of each vessel are connected by means of the connection C
and centre valve D.
The gas generator chambers are connected by means of the steam injector
refractory lined aspiratory flue E.
The steam jets F are placed at each end and opposite the cone shaped sectional
flue G in centre wall opposite the flue F¹.
For enriching the gas with fluid hydrocarbons a special valve and connections H
are provided by which the fluid hydrocarbons can be injected either per se or along
with steam into the incandescent fuel in generator or into the cavity between the

page_text: external casing and refractory lining of gas generator I by which the liquid hydro-
carbon enters into the fuel containing chamber by means of the passages J formed in
refractory lining.
In the recuperator chambers special radial and corrugated tiles K are provided
for the accumulation of the sensible heat of the gas and its restoration to the air,
proceeding to support the partial combustion of the fuel for the production of
the gas.
The steam jets valve F are provided with a reversing valve by which it can be turned
alternately into one chamber and then into another, the same action reversing the
supply of liquid hydro-carbon, and by certain well known mechanical arrangements
the centre valve may also be reversed.
The process is as follows:-
The carbonaceous and preferably semi-bituminous, or it may be anthracite, fuel is
charged into the gas generator chambers A and by means of a steam jet air aspirator
is rapidly raised to a fairly uniform condition of incandescence.
When the temperature equivalent to this condition is attained the steam jet valve
of air aspirator and the lower reversing gas and air centre valve are reversed and the
steam jet aspires the air through centre valve and recuperator chamber (becoming
heated therein) into the fuel, which is soon raised to a condition of bright
incandescence.
The steam, the volatile hydrocarbons-the CO2 and CO resulting from the vivification
of the fuel are aspired by the steam jet over division wall into second gas generator,
the steam in contact with incandescent fuel is split up into its constituent parts H,
and O the following reactions resulting viz.
2 H, OC 4 H + CO2 + C = 4 H + 2 CO
the carbon-dioxide (CO2) produces in contact with incandescent carbon and by the
following reaction viz. CO, +0= 2 CO or carbon-monoxide-adding to the volume
of carbon-monoxide already produced by a former action.
The liquid hydrocarbon is permanently gasified and its watery vapour is dissociated
consequently the resultant gas is of a high calorific character, its sensible heat in
passing descensionally through recuperator is absorbed and this heat at an alternate
and sequent period is given up to the air flowing to support combustion, consequently
the latter action is more intense and less fuel is required to be oxidised to CO₂ to
raise the fuel to the desirable condition of incandescence.
The corrugated vertical radiating tiles in recuperator have the advantage over
checker-brickwork that they are more durable and do not get so easily clogged
with deposited carbon or tarry matter.
The gas outlet at the base of recuperator chamber may be provided with a
hydraulic seal.
The circular or guard wall providing an annular cavity around hearth of gas
generator allows the air to enter equally around and into fuel.
I provide clinker doors M as shewn in figure 5 by which I can easily remove the
clinkers and ash.
I provide a special platform N at the level of the clinker doors or I may place the
recuperator part of vessel below floor level as shewn.
When I desire to remove the clinker in semi-liquid form by the addition to the fuel
of a fluxing agent such as lime, I construct the gas generator in the form shewn in
figure 8 in sheet 2 of drawings.
The cone shaped section offers facility for a light construction of refractory lining
for gas generator of a basic character as distinct from a siliceous one; this allows the
use of a fluxing agent such as lime to be added to the fuel to form a fusible
amalgamation of the earthy and incombustible constituents of the fuel, and without
destroying the refractory lining of the vessel.
I prefer to construct the basic lining of dolomitic limestone, ground and mixed
when hot with highly heated anhydrous tar, and placed in situ at a high temperature.
For the liquid clinker arrangement I may employ the water casing as shewn, in

page_text: order to maintain the lining at a lower temperature. I may inject the steam into
generator when fuel therein is in a state of incandescence, by means of an encircling
steam pipe placed above the upper level of fuel and rely upon a pleuum pressure to
supply the necessary air for the revification of fuel but I usually prefer the arrange-
ment shewn by which the steam injector acts as an aspiratory agent.
In sheets 3 & 4 of drawings, Figures 11. 12. 13 and 14 shew rospectively a vertical
section, plan in section and elevation and plan of another modification, which I term
the Duplex, of my Invention.
In this arrangement instead of having two gas generating vessels working in
unison according to a cycle of reactions already described and built quite in
separate casings, I construct the two gas generator chambers in one casing divided
from each other by a hollow division wall.
Referring to Figures 11, 12, 13 and 140 is one gas generator chamber, P is the
other is the hollow division wall, the hollow part or Cavity R of which, serves
for the escape of the gas into vertical down cast flue S.
The air to support initial and partial combustion of fuel is heated by passing
under or flowing through special floor tubes or pipes T.
The fuel is fed into generator chambers by the feed hoppers U, in which the planed
and sliding cover plate V is moved by lever and handles W.
Before the fuel is fed or charged into balanced and weighted close contact hopper
bell X, the sliding plate V is moved over the hopper, and the bell can he lowered or
raised to allow the fuel to fall into gas generator chamber without causing any
serious escape of gas.
A reversing swing valve Z is placed in centre of division wall; a chain wheel
arrangement and handle Z Z is provided for actuating said valve, simultaneously
with the steam jet air aspirating valve ZZZ.
After the fuel is charged into both gas generator chambers to the height of say,
five feet, the steam jet air aspirator F is turned on by the movement of handle ZZ,
the same manoeuvre throwing over or reversing swing gas and air valve Z so that
the products of combustion of the fuel in the generator through which the air is being
aspired, are compelled to descensionally traverse the fuel in the other chamber before
escaping into down cast flue S. When the fuel in the generator has been raised to
the temperature of incandescence; the steam jet valve is reversed and with it the
reversing swing valve Z.
The steam jet aspires the volatile hydrocarbons from the newly charged fuel that
is just beginning to be revived, and with the carbon monoxide and carbondioxide pass
descensionally through the incandescent fuel in other gas generator chamber the steam
becoming dissociated according to the following reaction viz.
* H, O + C = A E + CO, + C = ± H + 2 CO
The volatile hydrocarbons are rearranged and escape along with other constituent
gases of which carbon-monoxide forms a high percentage.
The carbon-dioxide carried over from first gas generator, in passing through
incandescent fuel loses its stability and relinquishes half its volume of oxygen to an
equivalent of carbon forming CO-the combustible gases finally escape into and
through valve Z into down casi flue S from whence they pass to the gas supply
delivery or distributing main.
The
The reactions in first generator-NO₂ + 20 N + CO + C = 2 CO + N.
actions in second generator are as follows. 2 H, O+ U H₁ + CO + C
H,+2 CO-The combined gas from both generators is composed as follows 4 CO +
N+ 4 H.
=
4
This action continues as long as the fuel remains incandescent, as the temperature
of incandescence is reduced by the absorption of heat necessary to effect the before
mentioned reactions, viz. the dissociation of the steam and formation of carbon-
monoxide, the heat absorbed is however returned to the consumer, if the latter
rationally utilises the gas produced.

page_text: As soon as the temperature of incandescence has fallen below the degree necessary
to effect chemical reaction and the temperature in other gas generator has been
raised to the desired degree the steam jet valve and air and gas valves are
reversed.
It will be seen that the air constantly passes through both gas generator floor tubes
and that the gases produced in both gas generator chambers escape into the same flue.
When I require gas free from Nitrogen I may use, instead of air, pure oxygen
prepared by the Brin or other well known process.
Clinker doors are placed at two sides of each gas generator chamber, about a foot
above ground floor to facilitate removal of clinkers.
In sheet 5 of drawings the arrangement shewn in figures 15 and 16 which are
respectively a longitudinal section and plan is a modification of my Invention designed
to effect the production of a continuous supply of gas without requiring the reversal
of valves.
1 and 2 are the gas generator chambers 3 is the central hollow division wall with
gas escape flue 4 over which is turned the arch 5 enclosing if desired a steam
superheater coil or if necessary a steam generator 6 for steam air inducing jet
purposes.
The air is injected into fuel by means of the steam jet air inducers or air injectors 7
placed above the inclined double clinker doors S.
The fuel is fed into the gas generator chambers by means of the usual bell feed
hoppers already described or by the automatic arrangement shewn at 9 consisting of
travelling endless chain, revolving on two chain wheel drums 10 actuated from the
outside.
The fuel falls on to chain through the openings 11, which are always kept covered
with fuel, the slow forward movement of chain grate carries the fuel into gas
generator chamber.
The clinkers are removed and the fires are agitated by a similar automatic
arrangement 12 the clinkers falling into the ash pit 13 from which they can be easily
withdrawn.
I may provide the ordinary firebars instead of the automatic arrangement shewn
and for a finely divided condition of fuel I may use a solid hearth.
I provide a flue cleaning door 14 by which I can clean central flue and I also
provide a swing gas regulating valve 15 actuated by a weighted lever 1.6.
In this last described modification of my Invention the chemical action involved in
my process is as follows.-A given depth or thickness of fuel suitable for the range of
direct chemical action, generally about 3 feet 6 inches is obtained, and the steam
pressure effecting a supply of air to the lower level of the fuel oxidizes the latter
to CO2, the sensible heat of this gas and the direct contact of the heated embers
raises the super level fuel to a state of incandescence, in contact with this latter fuel
in its condition of incandescence the CO, is converted into Carbon-monoxide and the
steam used for the injection of the air is also dissociated. The fuel newly charged is
maintained at such a level as to be above the soffit of central arch that is directly over
the escape or central outlet in division wall.
Consequently the volatile hydrocarbon gases evolved, as soon as the newly fed fuel
attains the temperature of volatilisation, cannot escape into gas main without
descending through the incandescent level of fuel and becoming in their contact with
the incandescent fuel less liable to deposit as tar in the flues.
The gas therefore produced from this latter combination or arrangement although
not so equable and rich in calorific units nevertheless is suitable for many operations
in which gaseous fuel is an agent.
Referring to sheet 2 of drawings figures 9 and 10 shew the condensing apparatus
I use when I desire to condense the gases produced in the gas generators herein
described.
The apparatus consists of a rectangular casing of sheet or cast iron having
Water is
horizontal shelves or water lined baffers formed of corrugated sheet, iron.

page_text: kept in continuous circulation in the bafflers or divisions each baffler having its own
delivery and escape pipe.
The condensed liquid from gas flows away by a pipe provided with a hydraulic
seal.
The corrugated surfaces of the bafflers offer a great area of cooling surface to
the gas.
The divisions or bafflers can be placed vertically instead of horizontally in
condensing apparatus.
Having now particularly described and ascertained the nature of my said Invention
and in what manner the same may be performed I declare that what I claim is
1st. The method of generating gaseous fuel and in plant therefor substantially as
shewn and described in figures 1 to 8.
2nd. The steam jet arrangement for aspirating the gas and air through central
division wall substantially as herein shewn and described.
3rd. The method of constructing the recuperator chambers substantially as herein
shewn and described.
4th. The method of constructing gas generator chamber or vessel the use of basic
refractory linings substantially as shewn and described in figure 8.
5th. The method of generating gaseous fuel and in apparatus therefor substantially
as shewn and described in figures 11. 12. 13 and 14.
6th. The manner of heating the air required for generating the gas substantially
as shewn and described in figures 11. 12. 13. and 14.
7th. The modified arrangement of plant for generating gaseous fuel substantially
as shewn and described in figures 15 and 16.
8th. The apparatus for condensing the gas substantially as shewn and described.
Dated this 12th day of August 1887.
B. H. THWAITE.