IMPROVEMENTS IN OBTAINING BENZOL AND OTHER HYDROCARBONS
Year: 1883

page_text: LETTERS PATENT to George Edward Davis of The Willows, Fallowfield,
Manchester, in the county of Lancaster, Consulting Chemist for an Invention
of "IMPROVEMENTS IN OBTAINING BENZOL AND OTHER HYDROCARBONS
"
PROVISIONAL SPECIFICATION left by the said George Edward Davis at
the Office of the Commissioners of Patents on the 18th September 1883.
GEORGE EDWARD DAVIS, of The Willows, Fallowfield, Manchester, in the
county of Lancaster, Consulting Chemist "IMPROVEMENTS IN OBTAINING BENZOL
AND OTHER HYDROCARBONS"
This invention relates to improvements in the extraction of benzol and other
volatile hydrocarbons from a mixture of gases.
In the process described in the specification of Letters Patent granted to me
N° 5717 dated the thirtieth day of November one thousand eight hundred and
eighty two, the oil used for absorbing, and likewise the gases from the
distillation of coal were cooled in an air cooler or a freezing machine of the
ordinary pattern.
I have found by experiment that the said process is also partly applicable to the
gaseous products resulting from the distillation of shale and to a certain degree to
the various mixtures of gases evolved from gas producers, coke ovens and other
processes and which consist essentially of hydrogen and carbonio oxide gases
holding benzol amongst them in a state of vapor. The relatively large volume of
these gases, however, renders it more difficult to extract the benzol from them than
from those evolved in the distillation of coal. Although this may to a certain
extent be effected by the process described in the specification of my said former
Letters Patent I find considerable economy is effected by my improved process as
follows:-
The gases beforementioned, evolved from the distillation of coal or from
coal-shale, or from coke ovens, or from gas-producers, or from any other source,
containing benzol or other light hydrocarbon vapours diffused through them, are
compressed, either by means of an ordinary compressing or condensing engine or
PI1

page_text: by combining the ordinary gas exhauster with a suitable cooling and expansion
apparatus or with a compression cooling and expansion apparatus. This operation
of compression results in the production of much heat. The compressed gases are
cooled by a stream of water or other convenient liquid after which they are brought
into contact with a heavy hydrocarbon oil to absorb the benzol or other volatile
hydrocarbone. In certain dispositions of the apparatus it will be advantageous to
treat the compressed gases with hydrocarbon oils at a later period.
The operation of compression alone will not be sufficient to absorb the whole of
the benzol from the gases, these compressed gases must therefore be allowed to
expand, during which operation they become cooled to as low a temperature as
desired. During the expansion, or afterwards, as may be found convenient, the
cooled gases are passed through the washers, scrubbers or other apparatus
containing the hydrocarbon absorbent and by these means the temperature of the
oil and that of the gases can be kept under control and as low as is practically
required.
The present improvements can also be advantageously employed in connection
with separate air coolers or freezing machines as described in the specification of
my said former Letters Patent but I believe the process above described to be more
economical.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said George Edward Davis in the Patent Office on the 18th March
1884.
GEORGE EDWARD DAVIS, of The Willows, Fallowfield, Manchester, in the
county of Lancaster, Consulting Chemist "IMPROVEMENTS IN OBTAINING BENZOL
AND OTHER HYDROCARBONS".
This Invention relates to improvements in the extraction of benzol and other
volatile hydrocarbons from a mixture of gases.
In the process described in the specification of Letters Patent granted to me
No 5717 dated the thirtieth day of November one thousand eight hundred and
eighty two, the oil used for absorbing, and likewise the gases from the distillation
of coal were cooled in an air cooler or a freezing machine of the ordinary pattern.
I have found by experiment that the said process is also partly applicable to the
gaseous products resulting from the distillation of shale and to a certain degree to
the various mixtures of gases evolved from gas producers, coke ovens and other
processes and which consist essentially of hydrogen and carbonic oxide gases
holding benzol amongst them in a state of vapor. The relatively large volume of
these gases, however, renders it more difficult to extract the benzol from them than
from those evolved in the distillation of coal. Although this may to a certain
extent be effected by the process described in the specification of my said former

page_text: Letters Patent I find considerable economy is effected by my improved process as
follows:-
The gases before mentioned, evolved from the distillation of coal or from coal
shale, or from coke ovens, or from gas producers, or from any other source
containing benzol or other light hydrocarbon vapours diffused through them, are
compressed, either by means of an ordinary compressing or condensing engine or
by combining the ordinary gas exhauster with a suitable cooling and expansion
apparatus or with a compression cooling and expansion apparatus. This operation
of compression results in the production of much heat. The compressed gases are
cooled by a stream of water or other convenient liquid or by an air cooler after
which they are brought into contact with a heavy hydrocarbon oil to absorb the
benzol or other volatile hydrocarbons. In certain dispositions of the apparatus it
will be advantageous to treat the compressed gases with hydrocarbon oils at a later
period.
The operation of compression alone will not be sufficient to set free the whole of
the benzol from the gases, these compressed gases must therefore be allowed to
expand, during which operation they become cooled to as low a temperature as
desired. During the expansion, or afterwards, as may be found convenient, the
cooled gases are passed through the washers, scrubbers or other apparatus
containing the hydrocarbon absorbent and by these means the temperature of the
oil and that of the gases can be kept under control and as low as is practically
required.
In order to enable my invention to be fully understood I will proceed to
describe the same by reference to the accompanying drawing in which figure 1, is
a section of the washer I employ in carrying out my invention; figure 2, is a plan
of the perforated divisions in the same and figure 3, shews the complete
apparatus I employ for absorbing benzine and other hydrocarbons from gaseous
mixtures.
The compressed gases arriving by the pipe a, figure 3, are compressed in the
cylinder b, and cooled in the cooler c, they then expand into the cylinder or
expansion chamber d, from whence they pass by the pipe k, into the outer jacket
of the tower g, Leaving this jacket by the pipe 1, they pass through a layer or
layers of oil or other suitable absorbent in the washers e, e, and thence into the
tower by the pipes f.f. The expanded and cooled gases then ascend the tower,
which is packed with boards or other suitable material down which a graduated
quantity of the absorbing liquid is caused to flow. The benzol and other light
hydrocarbon vapor is absorbed by the oil and the denuded gas passes away by the
pipe h. The pump j, supplies the absorbing liquid to the tower cistern h, by means
of the pipe o, o, this absorbing liquid finally finding its way into the washers e, e,
by the pipe m
The present improvements can also be advantageously employed in connection
with separate air coolers or freezing machines as described in the specification of
my said former Letters Patent, the gases may be cooled down by the expansion
method herein before described to a low temperature, or by any other method
already known, in order to free them from any excess of watery vapour, and then
subjected to a further refrigerating influence in the washer itself.
For this purpose the cooled gases are passed into the washers e, e, figure 3, one
of which is shown in detail in figures 1, and 2.
The washer is so constructed as to allow of the circulation of a refrigerating
medium which may be a portion, or the whole, of the expanded and cooled gases,
or any fluid medium capable of being employed for the purpose.
The gases pass in at the inlet pipe q, indicated by the arrow and find their way
into the chamber &, from whence they pass through the central pipe and through
the absorbing material lying in the chamber m. Leaving the chamber m, by the
pipe q, the gases pass in turn similarly through the chambers j, f, and c, finally
leaving the washer by the pipe r, The absorbing material enters the washer by
the pipe s, and runs through the chambers c, f, j, and m, and out of the apparatus

page_text: by the pipe o, saturated with benzol and other hydrocarbon vapours. The
refrigerating medium enters the apparatus by the pipe p, and finds its way through
the refrigerating chambers n, k, g, d, and a, making its exit by means of the pipe t.
Figure 2, is a plan showing the construction of the perforated divisions in the
chambers c, f, and m.
I find that this washer can be used to great advantage in an earlier stage of the
process of obtaining benzol and other hydrocarbons from gaseous mixtures resulting
from the treatment of coal by heat. In the earlier stages of the process it is
necessary to separate the ammonia and the use of this washer enables much
sulphuretted hydrogen which was formerly wasted to be utilized. In this case the
washer is fed with water or unsaturated ammoniacal liquor and the gases passed
through in the same manner as when used for the extraction of benzol. Instead
however of passing cold gases or cold fluids through the chambers n, k, g, d, and a,
warm liquids are used whereby the solution of benzol and other hydrocarbons in
the liquor is to a great extent prevented and the absorption of sulphuretted
hydrogen reduced to a minimum the benzol passing on with the other gases.
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
Firstly. The methods of obtaining benzol and other hydrocarbons from gaseous
mixtures by means of compression, expansion and refrigeration substantially as
herein before described.
Secondly. The use for the purpose of removing benzol and other hydrocarbons
from gaseous mixtures of the apparatus herein before described and represented in
figures 1, 2 and 3 of the accompanying drawing.
Thirdly. The use for the purpose of purifying gaseous mixtures containing benzol
and other hydrocarbons of the washer hereinbefore described and represented in
figures 1, and 2, of the accompanying drawing.
In Witness whereof I the said George Edward Davis have hereto set my hand
and seal this eighteenth day of March, in the year of our Lord one thousand
eight hundred and eighty four
ARODA