Improvements in and Apparatus for the Separation of Free Carbon from Tar.
Year: 1899

page_text: Date of Application, 31st Jan., 1899
Complete Specification Left, 21st Aug., 1899-Accepted, 23rd Sept., 1899
Improvements in and Apparatus for the Separation of Free
Carbon from Tar.
I, FREDERIC LENNARD, of the Firm of Forbes, Abbott & Lennard Limited, of
70 Gracechurch Street, in the City of London, Chemical Manufacturers, do
bereby declare the nature of my invention to be as follows:-
―
Tar, and especially coal-gas tar, contains free carbon, which retards the dis-
tillation of the tar, causes undue wear and tear of the distilling apparatus and
reduces the value, for agglomerating purposes, of the pitch, produced from dis-
tillation of the tar.
My invention has for its object to separate the free carbon from the tar so as
to increase the value of the pitch produced when the tar is distilled and to obtain
the said free carbon in a valuable form for electrical and other purposes.
According to my invention I dilute the tar, from which the carbon is to be
separated, with naphtha, light oil, or any other suitable oil, or spirit, of low
specific gravity, to such an extent as to neutralize the viscous nature of the
tar and produce a mixture having an appreciably lower distilling point than the
tar alone has. Having so diluted the tar I pass the mixture into a chamber
or retort externally heated to the volatilizing point of the mixture, and subject
it to the action of steam which has the effect of depriving it of practically all
its liquid portion, the free carbon being deposited in the form of a rough powder.
The chamber or retort in which the mixture is so treated is preferably of
somewhat conical form smaller at bottom than at top and is provided
with a rotating scraper and with a spreader at top to distribute the mixture
of tar and light oil or spirit the steam being admitted by a jet or jets pro-
jecting upwards from the lower part of the chamber or retort the bottom of
which is provided with a seal, which may be constituted for example by a
water well or an air-tight receptacle into which the carbon falls and from which
it can be removed at intervals. The volatile products driven off from the mixture
can be condensed the lighter oil or spirit being recovered for re-use and the
remainder being conducted (if desired through an interchanger through which
the aforesaid volatile products pass) to a still which can be heated by the other-
wise waste heat from the aforesaid chamber or retort. The tar to be treated can
be preheated if desired by passing it through an interchanger through which the
products of distillation pass from the still."
nated this 21o4 dow of Ton 1900
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: Improvements in and Apparatus for the Separation of Free
Carbon from Tar.
I, FREDERIC LENNARD, of the Firm of Forbes Abbott & Lennard Limited, of
70 Gracechurch Street, in the City of London, Chemical Manufacturers, 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:-
Tar, and especially coal-gas tar, contains free carbon, which retards the dis-
tillation of the tar, causes undue wear and tear of the distilling apparatus and
reduces the value, for agglomerating purposes, of the pitch, produced from dis-
tillation of the tar.
1. My invention has for its object to separate the free carbon from the tar-so as
to increase the value of the pitch produced when the tar is distilled and to obtain
the said free carbon in a valuable form for electrical and other purposes:...
According to my invention I dilute the tar, from which the carbon is to be
separated, with naphtha, light oil, or any other suitable oil, or spirit, of low
specific gravity, to such an extent as to neutralize the viscous nature of the
tar and produce a mixture having an appreciably lower distilling point than the
tar alone has. Having so diluted the tar I pass the mixture into a chamber,
or retort, externally heated to the volatilizing point of the mixture, and subject
it to the action of steam which has the effect of depriving it of practically all
its liquid portion, the free carbon being deposited in the form of a rough powder.
The chamber, or retort, in which the mixture is so treated is preferably of
somewhat conical form, smaller at bottom than at top, and is provided
with a rotating scraper, and with a spreader at top, to distribute the mixture
of tar and light oil, or spirit, the steam being admitted by a jet, or jets, pro-
jecting upwards from the lower part of the chamber, or retort, the bottom of
which is provided with a seal, which may be constituted, for example, by a
water-well, or an air-tight receptacle into which the carbon falls and from which
it can be removed at intervals.. The volatile products driven off from the mixture
can be condensed, the lighter oil, or spirit, being recovered for re-use, and the
remainder being conducted, (if desired through an interchanger through which
the aforesaid volatile products pass) to a still, which can be heated by the other-
wise waste heat from the aforesaid chamber, or retort. The tar to be treated can
be preheated if desired by passing it through an interchanger through which the
products of distillation pass from the still.
The accompanying drawing represents apparatus suitable for the purposes of
my invention, Figure 1 being a sectional elevation, Figure 2 a plan, and Figure 3
an enlarged section of the chamber or retort B.
The mixture of tar and oil, or spirit, of low specific gravity, is supplied from
a tank A, (provided with an agitator) by the pipe a, to the chamber, or retort, B,
heated by the furnace B2, and provided with a rotating scraper b, and with a
spreader 62. C is a pipe and jet by which steam is admitted and projected
upwards from the lower part of the chamber, or retort, B, the bottom of which
is provided with a water-well B³, constituting a seal into which the carbon falls
and from which it can be removed as required by the outlet b³. The volatile
products driven off from the chamber, or retort, B, pass off by the pipe D and
through the coil of the interchanger and condenser E from which the condensed
portion passes into the receiver F, the uncondensed portion passing through the
coil in the auxiliary condenser G, and thence into the receiver H, and it can be

page_text: used for mixing with a further quantity of tar. The products from the receiver F
pass outside the coil in the interchanger and condenser E through which the
products from the chamber, or retort, B, pass as aforesaid; the said products
then passing, by the pipe e, to a still I, which can be heated by the hot products
of combustion from the furnace B2 which heats the chamber, or retort, B the said
products passing through the flue, or passage, B3. The first, or lighter, products
of distillation from this still I, are passed through the fractionating column J,
and by the pipe j, through the coil in the interchanger K and thence through
the condenser L into the receiver M, or receivers. The heavier, or last, portions
of distillation from the still I, afterwards pass through the pipe i, and inter-
changer K, and condenser L into a receiver, or receivers, therefor. The residue
left in the still is withdrawn by the outlet 22, for use, or for further treatment
if required. The condensing medium for the interchanger K can be products
of distillation from the chamber, or retort, B, as in the case of the inter-
changer E, or water, or other condensing agent, may be used in either, or both,
of them.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I
claim is:-
:-
1. In the distillation of tar, diluting it with an oil, or spirit, of such lower
specific gravity as to produce a mixture having a sufficiently lower distilling
point than the tar alone has, and subjecting the mixture to the action of heat
and of steam to effect the volatilization of the liquid portion and the deposit of
the free carbon substantially as hereinbefore described.
2. In apparatus for the distillation of tar according to the preceding claiming
clause a chamber, or retort, of conical, or approximately conical, form, smaller
at bottom than at top and provided with a distributor and a rotating scraper, and
with means for admitting steam at the lower part and with a seal to allow of the
removal of the deposited carbon substantially as herein before described.
3. Apparatus for distilling tar consisting of the combination of a chamber, or
retort, as described, provided with means for admitting steam, and with a seal
for the removal of the deposited carbon, means for obtaining the lighter oil, or
spirit, a still heated by the waste heat from the said chamber, or retort, and means
for conducting the heavier oils into the said still all substantially as hereinbefore
described and illustrated in the accompanying drawings.
Dated this 21st day of August 1899.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.