A NEW OR IMPROVED APPARATUS FOR PURIFYING AND ENRICHING COAL GAS
Year: 1886

page_text: Coal Gas.
"
I, ALEXANDER DEMPSTER of the Rose Mount Iron Works, Elland, Yorkshire,
Gas Engineer do hereby declare the nature of my invention for "A NEW OR
IMPROVED APPARATUS FOR PURIFYING AND ENRICHING COAL GAS and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention consists in a new arrangement and construction of apparatus for
purifying and enriching coal gas on its passage through the tar extractor, by
which means I am enabled to arrest the heavy impurities of coal gas such as tar,
ammonia, carbonic acid, and sulphuretted hydrogen at an early stage in the
manufacture of gas.
Such being the nature and object of my invention I will now proceed to describe
the same more fully, and the manner of putting same into practice.
In the accompanying drawings Fig. 1 is section, and Fig. 2 plan view of
apparatus constructed according to my invention.
A is a rectangular or other form of box or chamber and is subdivided by
perforated plates B which extend downward nearly to the bottom of the chamber.
Underneath the chamber A is another chamber or carburetter C having a coiled
pipe D therein charged with steam for heating the tar, and E is a pipe perforated
with small holes for supplying atmospheric air which is arranged to pass through
the light volatile oils on the top of the tar.
The gas on its way to the ordinary purifiers passes through this apparatus and
enters at F and of necessity must impinge against the surfaces of the perforated
plates B which arrest the tarry matter contained therein.
The bodies thus arrested and collected will fall down between the plates B and
lodge in the bottom of the chamber A overflowing through the outlet G and into
the carburetter C the tar finally passing out of the said carburetter at the
overflow H. The lighter volatile oils float on the top of the tar, but I extract
therefrom as much of the hydro-carbons as is possible by means of jets of warm
air which are discharged under the surface of the floating matter.
To do this I employ a chamber I containing a quantity of tar which is kept at
a suitable temperature by a steam pipe J which is immersed in the tar, and is also
connected to the coil D which is supplied with steam thereby. Atmospheric air

page_text: enters the chamber I at point K which intermingles with the warm hydro-carbon
vapours arising from the tar, both of which pass out from the chamber at L and
are conducted by pipe M to the perforated ring E from which perforations the
warm air escapes, the position of the ring E being so arranged that the perforations
are clear of the floating bodies; but in order that the warm air may penetrate and
pass through the light volatile floating bodies I place over each perforation in the
ring E a concave dish a the lower edges of which dip in the liquor, consequently
the warm air must pass through it, in doing which it takes up a further quantity
of hydro-carbons which pass up the small pipes N and get forward through the
perforated plates B and pass out at point P and forward to the purifiers.
It will be apparent that when the vapours escape out of pipes N that they will
meet and come into contact with any tarry matter which may be falling into the
chamber A in doing which the value of the properties will be increased.
If the gas passing through this purifier or extractor is not sufficient to give off
enough tar as to continuously supply the carburetter, additional tar may be
supplied thereto at point R from other sources.
The carburetter herein referred to can be employed without the extractor.
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 construction of a purifier, tar extractor, and gas carburetter
composed of a box A divided by plates B, and employed in combination with a
carburetter C for purposes set forth.
Secondly. The perforated ring E and concave dishes a for discharging air into
the floating volatile oils.
Thirdly. The chamber I and parts connected therewith when employed in
combination with carburetter C, and used in the manner and for purposes set
forth.
Dated this 90th day of March 1886