Improvements in the Distillation of Tar, Oil, Resin, and Liquid Hydrocarbons in the Manufacture of Illuminating and Heating Gases therefrom, and in Apparatus for that Purpose.
Year: 1886

page_text: Improvements in the Distillation of Tar, Oil, Resin, and Liquid
Hydrocarbons in the Manufacture of Illuminating and Heating
Gases therefrom, and in Apparatus for that Purpose.
I WILLIAM BURNS of 32 Elmwood Terrace, Leith in the County of Mid-Lothian,
Consulting Engineer and Chemist, do hereby declare the nature of my said invention
for IMPROVEMENTS IN THE DISTILLATION OF TAR, OIL, RESINS AND FATS, AND IN THE
MANUFACTURE OF ILLUMINATING AND HEATING GASES, FROM LIQUID HYDROCARBONS
AND IN APPARATUS FOR THAT PURPOSE, to be as follows:-
I provide a double distilling retort which may be made of cast iron or malleable iron
or other refractory substance and of any convenient size, and may be made cylindrical
eliptical or egg shaped, I prefer the cylindrical as the most convenient form, I form a
semi-cylindrical channel on the bottom side of the external cylinder extending the
whole length of the cylinder, in which an archemedian screw is made to revolve, the
shaft working through a stuffing box in the end of the cylinder. Inside this said
cylinder I fix another cylinder about 3 inches less in diameter, so as to leave an
annular space between the two cylinders for steam. These cylinders are joined at the
ends steam tight. I cut longitudinal piece out of the bottom of the inside cylinder equal
in width to the diameter of the archemedian screw, so as to leave a free communication
between annular space and the body of the retort. On the top of the inside cylinder
I form a longitudinal gutter, and close the cylinders at the ends with gas tight doors.
The retort constructed as above described I set in a furnace longitudinally and
horizontal so that the semi cylindrical screw bed projects down into the furnace, I
turn a fire brick arch over the whole retort, so as to form a flue space right round the
cylinder. The tar or oil is charged or fed into the retort from the end over the
furnace door by a pipe from a tank placed at a sufficient height above the retort to
allow the tar or oil to flow into the retort by gravitation, I insert a water pipe
through the end of the retort into the gutter on the top, in connection with the
annular space; the other end of the pipe is put in connection with the water cistern
with regulating valve in such a manner that a fine stream of water can be made to
run into the gutter on the top of the internal cylinder. At the opposite end of the
retort from the furnace end, a discharge pipe is inserted in the bottom, with a
regulating valve or cock. The eduction or discharge pipe for the vapours and gases

page_text: is inserted on the top of the retort above the discharge pipe. In connection with the
above described retort and forming part of it I fix an iron decomposing retort or set
of retorts, which may be cylindrical, eliptical or D shaped, with gas tight lids and
exit pipe similar to ordinary gas retorts, with the addition of an inlet pipe which I fix
at the back end of the retort, and connect it with the eduction pipe from the distilling
retort. Inside the decomposing retort I place a loose pipe or saddle piece perforated
with a number of small holes; the perforated pipe to extend the whole length of the
retort, but is smaller in diameter so that the end of the perforated pipe will fit into the
inlet pipe at the end of the retort, and leave a vacant space above.
The discharge pipe from the decomposing retort is inserted in the mouth piece
above the furnace door, and led into a hydraulic main, and then into condensers and
lime purifiers.
These combined distilling and decomposing retorts form one complete novel
apparatus for making gas from tar, oil and other liquid hydrocarbons.
The inode of operating with these said retorts is as follows, I charge the decomposing
retorts with charcoal and scrap iron, so as to completely cover the perforated tubes. I
then charge the distilling retort with tar or oil till it is two thirds full; then I kindle
the fires under the retorts, and turn a small stream of water into the gutter on the top
of the internal cylinder, the water is then converted into superheated steam and
forces its way under the edges of the internal cylinder and then up through the liquid
tar or oil carrying with it the whole of the volatile hydrocarbon vapours of the tar
or oil; these mixed gases, hydrocarbon vapours and steam force their way through
the perforated tubes in the decomposing retorts, and through red hot charcoal and
iron scraps which completely decomposes the steam and vapours converting the
vapours into highly illuminating gas.
By this method of distilation a highly illuminating gas perfectly free from sulphur
compounds can be obtained; or a highly heating gas can be obtained in larger quantity
by increasing the quantity of water injected into the gutter and at the same time
increasing the temperature of the decomposing retorts. The heavy tar or pitch which
forms in the bottom of the distilling retort is forced forward into the discharging pipe
by turning the Archemedian screw. The quantity of tar or oil in the retort can
always be kept at the same level by regulating the speed of the feed and discharging
screw.
The novelty of the above mode of manufacturing gas is as follows, First the tar or
oil is first distilled by a combination of dry external heat and internal superheated
steam; in a retort which admits of being continuously fed and discharged, without
intermission whereby the equal density of, and composition of the hydrocarbon
vapours is maintained throughout the whole time of distilation.
2nd. The hydrocarbon vapours and steam is decomposed in a separate retort where
the vapours are distributed by a perforated pipe through and over a large surface of
red hot charcoal and iron which converts the whole into permanent illuminating or
heating gas as may be required.
3rd. The gas can be manufactured by this method of any required illuminating power
up to 60 candles at less cost than by any other method of making gas hitherto adopted.
Coals may be distilled at a low temperature in separate retorts to produce tar and
ammonia and the tar can then be converted into double the quantity of gas that can
be obtained by making gas direct from the coal, gas made from tar and steam is
perfectly free from sulphur compounds.
4th. When it is not required to make gas from the tar; the vapours from the
distilling retort can be turned into a condenser and converted into oil or naptha.
When resin or fat is required to be distilled, these substances are put into a close
steam tight vessel above the retort, and melted by steam, and the melted resin or fat
is then run into the distilling retort in the manner described for tar and oil.
Dated this 16th day of November 1886.

page_text: Improvements in the Distillation of Tar, Oil, Resin, and Liquid
Hydrocarbons in the Manufacture of Illuminating and Heating
Gases therefrom, and in Apparatus for that Purpose.
I, WILLIAM BURNS of 32 Elmwood Terrace, Leith in the County of Mid Lothian,
Consulting Engineer and Chemist, do hereby declare the nature of my invention for
MAKING ILLUMINATING GAS FROM TAR, RESIN, OIL AND LIQUID HYDROCARBONS, and in
what manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
For distilling tar and other liquid hydrocarbons, 1 employ a double distilling retort,
which may be made of cast iron or of Malleable iron, or other refractory material and
may be made of any convenient size, and may be made cylindrical eliptical or egg
shaped. I prefer the horizontal cylinder as being the most convenient form. I form
a semi-cylindrical channel on the bottom side of the external cylinder, extending the
whole length of the cylinder, in which an archemedian screw is made to revolve, the
shaft working through a stuffing box in the end of the cylinder; inside the said
external cylinder, I fix another cylinder about 3 or 4 inches less in diameter so as to
leave an annular space between the two cylinders for steam to pass through into the
tar. These cylinders I join at the ends steam tight. I cut a horizontal piece out of
the bottom side of the inside cylinder equal in width to the diameter of the screw, so
that I leave a free communication between the archemedian screw, the annular steam
space, and the body of the retort. Inside the cylinder over the screw I fix a hood in
the form of an inverted trough, and another two hoods I fix above the centre of the
cylinder, these hoods are made with serrated edges in the form of saw teeth, for the
purpose of dividing the vapours in passing under the edges. These hoods are for
intercepting and mixing the steam and tar vapours as they rise through the tar; on
the top side of the cylinder I form a longitudinal gutter; and close the ends of the
cylinder with gas tight doors.
The retort constructed as above described I set in a furnace longitudinally and
horizontal so that the semi-cylinder screw bed projects down into the furnace, I turn
a fire brick arch over the whole retort, so as to form a flue space right the cylinder.
The tar or oil fed into the retort from the end over the furnace door by a pipe from
a tank placed at a sufficient height above the retort to allow the tar or oil to flow into
the retort by gravitation.
I insert a water pipe through the end of the retort into the gutter on the top of the
inside cylinder, in connection with the annular steam space; the other end of the pipe
is put in communication with a water cistern with regulating valves in such a manner
that a fine stream of water can be made to run into the gutter on the top of the inside
cylinder; at the opposite end of the retort from the furnace end, a discharge pipe is
inserted in the bottom with a regulating valve.

page_text: The eduction or discharge pipe for the vapours and gas is inserted on the top of the
retort above the discharge pipe.
In connection with the above described retort and forming part of it, I fix an iron
decomposing retort. or set of retorts which may be eliptical, cylindrical, or D shaped,
with gas tight lids, and excite pipes similar to ordinary gas retorts; with the addition
of an inlet pipe which I fix on the back end of the retort, and connect it with the
eduction pipe from the distilling retort. Inside the decomposing retort I place a loose
pipe fluted, and perforated with a number of small holes, the perforated pipe extends
the whole length of the retort, but is much smaller in diameter, so as to leave a vacant
space above it to be filled up with charcoal.
The discharge pipe from the decomposing retort is inserted in the mouth piece
above the furnace door and led into a hydraulic main and then into condensers and
Jime purifiers.
These combined distilling and decomposing retorts form one complete novel
apparatus for making gas from tar, oil, and other liquid hydrocarbones.
The mode of operating with these retorts is as follows
I charge the decomposing retorts with charcoal and scrap iron so as to completely
cover the perforated pipe, and fill the retort full. I then charge the distilling retort
with tar, or oil, till it is two thirds full; then I kindle fires under the retorts and turn
a small stream of water into the gutter on the top of the internal cylinder of the
distilling retort; the water is then and there converted into steam, and superheated
in passing through the annular space into the tar, under the edges of the internal
cylinder.
The superheated steam in passing through the liquid tar, or oil, carries with it the
volatile hydrocarbon vapours of the tar, or oil, which in their passage upwards are
intercepted by the hoods and mixed with the less volatile and heavier vapours
discharged from the thick tar by the heat of the furnace on the bottom of the retort.
These mixed vapours and steam as they accumulate under the hoods force their way
under the edges and upwards through the excite pipe, and then through the perforated
tube in the decomposing retort, then through the red hot charcoal; which completely
decomposes the steam and hydrocarbon vapours into permanent illuminating gas.
By this method of distillation highly illuminating gas perfectly free from sulphur
compounds can be obtained; or a highly heating gas can be obtained in larger
quantity by increasing the quantity of water injected into the gutter, and at the same
time increasing the temperature of the retort. The heavy tar or pitch which forms
on the bottom of the retort is forced forward into the discharge pipe, by turning the
archemedian screw. The quantity of tar, or oil, in the retort can always be kept at
the same level by regulating the speed of the feed, and discharge screw.
The novelty of making gas from tar, and other liquid hydrocarbons by the above
method is as follows.
1st. The tar, or oil, is first distilled by a combination of dry external heat and
internal superheated steam; in a retort which admits of being continuously fed and
discharged, without intermission, whereby the steam and vapours of tar, are thoroughly
mixed and the equal density of the composition of the hydrocarbon vapours is
maintained throughout the whole time of distillation.
•
2nd. The hydrocarbon vapours and steam are decomposed in a separate retort
where the vapours are distributed by a perforated pipe, through and over a large
surface of red hot charcoal and iron scraps, which converts the whole into permanent
illuminating or heating gas as may be required.
3rd. Gas can be made by this method of any illuminating power required up to
60 candles at less cost than by any other method of making gas hitherto adopted.
Coals may be distilled under high pressure and low temperature in suitable retorts to
produce tar and ammonia, and the tar can then be converted into double the quantity of
gas that can be obtained by making gas direct from the coal. Gas made from tar and
steam as above described is perfectly free from sulphur and ammonia compounds.
4th. When it is not required to make gas from tar, the vapours from the distilling
retort can be turned into a condenser and condensed into oil or naptha.

page_text: When resin or fat is required to be distilled these substances are put into a close
steam tight vessel above the retort and melted by steam, and the melted resin or fat is
run into the retort and distilled in the manner described for oil and tar.
Referring to the drawings, Sheet 1. Fig. 1, is a plan of the distilling and
decomposing retorts, Fig. 2, is a longitudinal section on the line E, F, of the
distilling retort. Fig. 3, is a transverse section on the line A, B, Fig. 4, is a
longitudinal section on the line C, D. Fig. 7, is a section of the fluted and perforated
pipe, one quarter full size for distributing the vapours through the decomposing retort.
Fig. 8 shews a vertical section of a vertical retort, that may be substituted for the
horizontal retort C. Sheet 2 Fig. 5, is a front elevation of retorts and vertical
section of condenser. Fig. 6, is a back elevation of the retorts and condenser.
Sheet 3. Fig. 9, is a semi-sectional elevation shewing an arrangement for two benches
of decomposing retorts, one bench of 5 retorts on each side the distilling retort with
a saddle steam boiler placed over the distilling retort, with a fractional still placed over
the flue.
Fig. X is a section of the hydraulic main on a scale of half inch to a foot shewing
the arrangement for spreading the gas over a large area of tar.
In operating with the above apparatus I fill the tanks T, with tar and W, with
water, and I fill the distilling retort C, two thirds full with tar, and the decomposing
retort D¹ I fill with charcoal and scrap iron, and then close the doors tight, and kindle
fires under the retorts, at the same time I turn a small stream of water into the
gutter G, on the top of the internal cylinder C. The flame and hot gases from the
furnace are made to completely envelope the retort; the water as it runs along the
gutter G, is rapidly converted into steam, which is superheated in the annular space g,
between the two cylinders as it passes under the edges of the internal cylinder near the
furnace shewn at E Fig. 3. The steam with the volatile vapours from the thin tar, and
the less volatile, and heavier vapours from the thick tar, that are discharged from the
bottom of the still by the heat of the furnace, are intercepted by the hoods H, H, and
thoroughly mixed, and then escape under the serrated edges of the hoods and then up
through the top tar into the space above; the mixed steam and tar vapours then pass
through the perforated screen I, which intercepts and breaks up the froth that accumu-
lates on the top of the tar. The mixed vapours and steam now pass up the pipe J, and
down the injection pipe K, and enters the retort D₁, by passing through the perforated
pipe L which distributes the steam and vapours uniformly through the red hot charcoal
in the retort and connects the steam and tar vapours into permanent illuminating gas.
The gas formed in the retort D' passes up the pipe M and enters the hydraulic main N,
which is kept half full of tar; the hot gas passes into an inverted trough, which has its
edges diped into the tar; the gas in passing under the edges of the trough is devided
into small bubbles, by the saw teeth, and then passes up through a perforated plate
shewn at T, Fig. X, Sheet 3. which devides the gas into still smaller bubbles, which
distills off the volatile vapours of the tar, which are carried with the gas into the
condenser P, where the gas is cooled and the greater part of the suspended vapours
are condensed into the liquid state; and returned into the hydraulic main. The most
volatile part of the vapours taken up by the gas in the hydraulic main remain
permanently incorporated with the gas under all ordinary temperatures of the
atmosphere. The gas is led from the condenser by the pipe d, to a lime purifier
which absorbs the carbonic acid, but if the heat of the retorts is properly regulated
there will be no carbonic acid found in the gas, and therefore no necessity for a lime
purifier. As the distillation proceeds, the retort C, is fed with tar and water from the
tanks W and T, through the regulating valves V V₁ the quantity being measured by
the tumbling boxes Z, Z'. The tar passes down the pipe O, and enters the retort by
the mouth-piece Q. The heavy tar or pitch after it has discharged the greater part
of its volatile vapours is forced out at the valve R. by the screw S, which is kept
constantly revolving, and prevents the tar from charing and adhering to the bottom
of the retort.
The feed water enters the condenser at the top and falls upon a set of shallow trays U,U,
through which the air pipes pass, leaving a narrow annular space between the pipe

page_text: and the tray through which the water and gas flow in opposite directions, a current of
air passes through the condensing pipes e, and cools the gas, the water passes down
the pipe X and enters the gutter G, on the top of the retort.
The gas from the hydraulic main passes up the pipe a, into the condenser P, at the
bottom, and makes its exit at d, on the top. The ejected pitch from the retort (1, is
mixed with ground coal and chalk, as much coal dust being incorporated with the
pitch as it will absorb and mould easily into blocks, these blocks of pitch, coal dust
and chalk, are then submitted to destructive distillation in a separate retort, under
high pressure and low temperature to form additional quantities of tar to be made into
gas and the coke made into fuel and used in the distilling retort.
When it is required to make heating gas, a larger quantity of water must be used
in the retort C, and a quantity of air should be blown into the body of the retort D¹,
through the perforated pipes n, n, these tubes are inserted in the retorts in a position
where they are completely surrounded with the charcoal, the oxygen combining with
the charcoal, increases the temperature in the centre of the retort, to the required
degree to decompose the steam, and the carbonic acid formed in the centre of the
retort is rapidly converted into carbonic oxide in passing through the superincumbent
charcoal; by this means we get a large quantity of highly heating gas. The air
ought not to be mixed with the tar vapours in passing through the tube L because the
oxygen would in that case combine with the carbon in the vapours, and deteriorate
the in both heating and illuminating power.
gas
When cannel coal tar, is used alone, which contains the largest quantity of rich
hydrocarbons for making gas, it is advisable to blow a small quantity of air into the
decomposing retort in order to keep up a steady heat in the centre of the retort and at
the same time dilute the gas to the required standard.
In the foregoing description 1 have supposed that the water used would be soft
water, because if hard water containing much lime were used, it would soon chock up the
water channel, and steam annular space. In order to meet the case of hard water,
where soft water cannot be conveniently got; we must use a separate steam boiler
with proper blow off cocks, where the water can be converted into steam before it
enters the distilling retort. For that purpose, I use a saddle boiler placed over the
distilling retort, as being the most convenient form.
Fig. 9 on Sheet 3, shews an arrangement of apparatus that may be used with either
soft or hard water, S, is a saddle boiler placed over the retort C³, and heated by the
furnace flue, the water is injected into the bottom of the boiler by the pipes U, U, and
steam is blown from the top of the boiler into annular space in the retort C¹, by the
pipe U, this is a convenient form of apparatus; by having a set of decomposing
retorts on each side of the distilling retort we are enabled to work continuously,
because when one set of retorts require replenishing with charcoal we can shut down
the valve I which disconnects the retorts with the still and charge them with fresh
charcoal while the other set continues to do duty in decomposing the vapours; so that
there would be no intermission in the work.
When the temperature of the retorts get too low for decomposing from any cause,
it is easy to bring them up to the required temperature by shutting off the connection
with the still of one set at a time, and opening the valves n' which connects the mouth-
pieces with the flue of the retorts, then blowing air through the pipes n, n, the air
blast will soon bring up the heat of the interior of the retort to the proper temperature
and the carbonic oxide from the interior of the retorts being consumed in the flues,
heats up the exterior of the retorts. As soon as the temperature of the retorts is
brought up to the proper degree, the air blast is shut off, the valves n' are shut and
the valve I opened, and a connection established between the still C¹, and the hot
decomposing retorts.
The permanent gas in passing out of the retorts into the hydraulic main and
condenser is made to pass through the tar in numerous small globules, by first
entering the long trough T which is formed with serrated edges in the form of saw
teeth, the gas passes under the edges of the trough between the saw teeth,
which divides the gas into small bubbles and the gas is then divided into still

page_text: smaller bubbles by passing through a horizontal plate perforated with a number of
small holes, shewn in section by T, Fig. X. The hot gas by this means is spread over
a large surface of tar, and carries off the volatile naptha intimately mixed with the gas
into the condenser, where the greater part of the naptha, is condensed and returned
to the hydraulic main by the pipe X¹. The naptha and fresh tar frorm from the tank
meet at the point X" and mix as they pass into the hydraulic main; and enters the
bottom of the fractional still A, where the naptha and tar are thoroughly mixed by
passing through the perforated plate, E, and a portion of the naptha and a part of the
tar, is distilled, and the vapours pass into the hydraulic main by the pipe A¹ and mix
with the gas as it flows into the condenser, where part of the naptha is again
condensed into the liquid state, and again returned through the hydraulic main with a
fresh supply of tar, into the low temperature fractional still A, again to undergo
redistillation. It is this redistillation of a portion of the naptha along with fresh tar,
over and over, as described, that produces the highly volatile essential
which
increases the illuminating power of the gas. The greater part of the mixed tar and
naptha overflows into the pipe O, and enters the high temperature distilling retort
at Q, and is forced forward and mixed with the heavy tar by the revolving screw S.
The naptha dissolves the thick tar and makes it easier to evaporate.
.
vapours
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed I declare that what I claim is ;
1st. I claim the particular mode of making gas from liquid hydrocarbons by distilling
the said liquids in a double distilling retort, with steam annular space between the outer
and inner shells of the retort, and in mixing the vapours under hoods placed inside
the retort and then decomposing the said vapours in a separate retort, by passing
the vapours through red hot charcoal contained in the seperate retorts, constructed
and operated substantially as herein described.
2nd. I claim the use of a fluted perforated pipe surrounded with charcoal inside the
decomposing retort for distributing the hydrocarbon vapours and steam equally
through the charcoal.
3rd. I claim the blowing of air through fluted and perforated pipes placed inside
the decomposing retorts and surrounded with charcoal.
4th. I claim the mixing of the fresh hydrocarbon liquids with distilled naptha in
the hydraulic main, and then distilling the mixture in a low temperature still placed on
the top of the high temperature distilling retort, and then distilling the unevaporated
portion in the high temperature still.
5th. I claim the particular combination of the whole of the retorts and apparatus
shewn by the drawings marked sheet 1. 2. 3. and particularly described in the
foregoing Specification.