Process for Manufacturing Compact Pit Coal out of Pit Coal Dust, Slack, or Small Pieces of Pit Coal.
Year: 1892

page_text: Date of Application, 24th May, 1892-Accepted, 3rd Dec., 1892
COMPLETE SPECIFICATION.
Process for Manufacturing Compact Pit Coal out of Pit Coal Dust,
Slack, or Small Pieces of Pit Coal.
I, HENRY BIRKBECK of 34 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Chartered Institute of Patent Agents, do hereby
declare the nature of this invention (a communication to me from abroad by Erust
Bernhard Muller of 29, Matthesstrasse, Chemnitz, in the Kingdom of Prussia and
German Empire, Merchant) and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement :-
The processes hitherto used for the manufacture of compact coal possess the
following disadvantages
:―
: (1) The small coal has to be very highly heated. A complete chemical alteration
is thereby effected. The carburetted hydrogen (the bitumen) is melted and masses
of a coky nature are produced which are indeed applied for purposes of fuel; but
for chemical purposes (as for example the manufacture of gas) they are useless,
whilst the tarry products are at the same time entirely lost...
(2) In order to bind the small coal a large addition of tar or pitch is necessary,
so that the briquettes manufactured by this process are rendered very costly and as
a matter of fact the binding material and the price thereof is the chief factor in the
manufacture of briquettes by the old methods as well as other costs incidental to
these old methods, and
(3) The soft bodies produced are neither ready for use nor especially capable of
transport, but must rather first for the purpose of hardening be kept in drying
chambers and baked in order to harden same.
Apart from the considerable increase of price occasioned by this process the
products developed upon the said process of drying the briquettes have a most
penetrating and offensive smell which makes the carrying out of the process in any
populated district very obnoxious. The tar and oil products are also by this
process entirely lost.
All these defects are altogether obviated by this invention which affords the
following advantages and according to which
(1) The small coal need only be subjected to a temperature of not under 40° and
not over 70° centigrade.
(2) The tar or pitch addition for the binding of the coal particles is entirely
omitted in some cases while only in the case of inferior coal one to three per cent.
(1 to 3%) of tar is added and this only for the purpose of increasing the resistance
of the coal to the action of water and the weather.
(3) It is clear that this decrease of temperature and dispensing with the addition
of tar (or reduction in the amount thereof) must be compensated for by other means
as otherwise only brittle and quickly perishable briquettes would be obtained. This
compensation is effected as follows
-
(1) The pressure is increased to at least 800 kilogrammes.
(2) The coal by moistening or drying should be allowed to take up or retain
respectively not less than 5% and not more than 12% of water.
It is only by the co-operative action of the three above mentioned factors
(namely (1) a temperature of 40° to 70° (2) a pressure of over 800 kilogrammes
and (3) a water moisture of 5 to 12% of the coal) that the fluid matter (oily and
tarry matter or the bitumen) can be pressed out of the pores of the coal so as to unite
the small particles of coal together so that they do not afterwards fall to pieces.
For the practical application of the process therefore the small coal either by its
natural contents by drying or moistening must be brought to contain from 5 to
12% of water the poorer coal mixed with it 1 to 3% of tar or a correspondingly

page_text: small quantity of pitch and the mass then be subjected to a pressure of over
800 kilogrammes. The resulting product is immediately transportable and
applicable to the same purposes as the coal from the pit.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The improved process for the manufacture of compact blocks of coal from coal
dust, slack or small particles of coal by pressure such coal which must contain
5 to 12 per cent. of water at a temperature of from 40° to 70° centigrade and a
pressure of not less than 800 kilogrammes with the object that the bitumen or
natural tarry or the like matter may be brought to the surface of the coal and the
separate particles may be made to adhere to each other by means of the said
bitumen or the like matter and so avoid the chemical change which the coal would
undergo at a higher temperature substantially as and for the purposes hereinbefore
set forth.
Dated this 24th dove of May 1900
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.