IMPROVEMENTS IN THE MANU- FACTURE OF GAS, AND IN THE APPARATUS TO BE EMPLOYED THEREIN
Year: 1876

page_text: LETTERS PATENT to John Cornish Harcourt Sievier, of Holloway, in the
.
County of Middlesex, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF GAS, AND IN THE APPARATUS TO BE EMPLOYED THEREIN."
Sealed the 19th January 1877, and dated the 23rd October 1876.
PROVISIONAL SPECIFICATION left by the said John Cornish Harcourt
Sievier at the Office of the Commissioners of Patents on the 23rd October
1876.
JOHN CORNISH HARCOURT SIEVIER, of Holloway, in the County of Middlesex.
"IMPROVEMENTS IN THE MANUFACTURE OF GAS, AND IN THE APPARATUS TO BE
EMPLOYED THEREIN."
My Invention relates to certain improvements in the manufacture of gas, and in
the apparatus to be employed therein, the objects of the Invention being to produce
a greater quantity of gas from a given quantity of coal than has heretofore been
obtained, to afford a higher standard of purity and light or illuminating power, to
avoid destructive decomposition or distillation, and thereby effect a saving in all the
resultant elements and constituents of the coal, and to simplify and economize all
the processes in gas manufacture. And in respect of the so called residues the
Invention is eminently calculated to deal with them in a manner more effective,
concise, and satisfactory than is at present the case, as will be hereafter described.
It is well known that according to the system of gas making which has hitherto
been adopted, a more or less high degree of heat has been necessary in order to
effect distillation in the retorts, and that such high and excessive heat has burnt or
consumed a considerable quantity of gas while being generated, and that thus a
great waste has occured, and the quantity of gas due to a given weight of coal has
not been obtained in the gas holder. Moreover the sulphur impurities have been
eliminated in excess, and have necessitated the adoption of many descriptions of
purifying agents and apparatus, requiring constant attention, involving great
expense, and constituting in their best and most recent improvements an inadequate
means of effecting the objects sought.

page_text: Now according to this Invention the first and chief feature is to dispense with
the present necessity of excessive heat in the retorts, and to effect the decomposition,
distillation, and elimination of the constituent elements without destructive
distillation.
The principle is to work in vacuo, and I propose to carry out this principle as
follows-I form a bench of retorts (horizontal iron retorts by preference), the same
being made of a cylindrical form, or of a ☐ shape, or other convenient form,
and they are set in masonry with flue passages circulating or surrounding them, in
order that heat in the nature of heated air from a furnace or fire place may be
brought to bear upon their surfaces, other means of heating may if desired be
adopted.
The retorts may be supplied with a grating on which the coal rests, thereby
facilitating its distillation, and enabling the carbon residue to be withdrawn on the
grating without the necessity of raking out the retort. The liquid residues would
also be facilitated in their flow or pouring down from the solid carbon residue,
and may be collected in reservoirs communicating with the retorts by means of pipes
and valves.
The lids of the retorts are to be made so as to close hermetically, which is easily
arranged by means of a hinged door or lid closed by a lever action, and by suitable
packing. I propose to cut or form a circular, dovetailed, or other groove around the
internal surface of the lid, and to fill the same with a soft metal or metallic
compound or other suitable material which shall. jamb or shut against a projecting
circular rim on the retort. A yielding surface behind the soft metal will facilitate
the sealing of the lid on the mouth of the retort, but of course other means may be
adopted for the purpose.
To each retort a pipe is attached in communication with a main tube, and each
pipe is provided with a valve to shut off or open its connection with the main as
required, which main should be intercepted by or in connection with a water vessel,
chamber, or receptacle, or in other words with an hydraulic main of suitable
construction. The products then traverse the condensers, and are drawn directly to
an air pump, or to a vacuum chamber contiguous thereto, pipes and valves being
arranged for the purpose as required for the proper control of the operations to be
described, as will readily be manifest to any gas or pneumatic engineer. The air
pump is to be worked by a steam engine, and consequently by the apparatus
described it is evident that as perfect a vacuum will be obtained in the retorts as is
possible, the gaseous products being thus drawn to the air pump directly, or to the
vacuum chamber in the first instance, in which case a vacuum is previously effected
therein; the products may then be ejected by the pump (which is suitably con-
structed for the purpose) along a pipe or pipes to the scrubbers and purifiers or other
necessary appurtenances, and finally reach the gas holder, but with these last
mentioned details my Invention does not touch in regard to their improvement or
adoption.
I have given the position of the air pump as between the condenser and scrubber,
but I do not limit myself to such position, because experience may shew that it
would be preferable to let the air pump intervene at some other position in regard to
the retorts and general apparatus used ordinarily in gas manufacture.
Hitherto an exhaust has been used to draw away or to induce or facilitate the gas
following the course of the pipes, but by this Invention no such exhaust as is usual
in ordinary gas works will be I think requisite.
.
Between the retorts and the gas holder whatever scrubbing and purifying
apparatus may be necessary must intervene, the gas should in all cases be made to
pass through water, but in regard to any of these well known and usual appliances
my Invention has no direct reference except in so far as their simplification is
concerned, because there will not be the necessity of such purification as is now so
essential.
.
The modus operandi of this part of the Invention is as follows:-The retorts
I

page_text: being made by preference of large dimensions a charge of even one ton of coal may
be made in each retort, because the work will be slow and gradual instead of com-
paratively rapid as is now the case where the retorts are charged every six hours
with, say, five cwt. of coal, so that a charge of one ton will require renewal at
intervals of from 12 to 24 hours, more or less, the production of gas however will
not be in the result slower but quicker. The lids being closed the heat is supplied,
it being of course understood that the vacuum is already as perfect as possible, as
indicated by the gauges placed at suitable positions on the main or otherwise. The
air pump being set in motion the vacuum will very speedily be effected, and I
propose if practice should confirm me that the eduction pipe shall then be
temporarily closed by a valve. The reason of this is that it may be found in practice
preferable not to commence the withdrawal of the products at the first moment of
their elimination, but to keep the retort closed until such time as the decomposition
has become more active, and some pressure is indicated in consequence within the
retorts by suitable pressure gauges, then the eduction may be opened partly or fully,
and the action of the air pump resumed.
Since nature is opposed to a vacuum the gaseous or volatile elements of the coal,
such as hydrogen and carbon and other products, will be gradually eliminated, aided
in the most effectual manner by caloric, and thus decomposition will set in under
the most favorable circumstance which artificial means can promote, and with this
most important feature, viz., that no waste can possibly occur. The valves form a
subject of careful adjustment in such manner that when once the vacuum is
practically perfect communication between the retorts and the air pump may be
maintained, regulated, or checked as desired. Whether hereafter any modifications
in the adoption of this principle may be made experience may show, but at present
the foregoing appears to be a consistent modus operandi. Other valves will of
course be open to the gas holder and its interventions, and the holder being sub-
stantially in vacuo, the whole system of working will be facilitated.
When the gaseous and volatile products have become exhausted from the retorts
which will easily be ascertained, the valves will be closed wherever necessary, and
air will be let into the retorts by means of cocks on the eduction pipes, and the lids
can then be removed in order to withdraw the residue of carbon and any liquid
residues therein, but I propose to convey the greater part of the liquid residue by
a channel from the retorts to small reservoirs from which they may be collected at
will for further treatment. The liquid residues will also be collected by the
hydraulic main or water vessels or by condensation.
I have now explained the process of elimination in vacuo aided by caloric, but it
is evident that the degree of caloric will be far lower than at present required for
the destructive and wasteful distillation and elimination as now carried on."
Now I further propose to aid the elimination of gaseous products, and to effect
the general decomposition of the coal while subject to heat in a vacuum by means
of electricity. If galvanic electricity is used I employ powerful batteries of a
constant nature, and bring the poles in contact with the coal by means of metal
plates or rods, the conducting copper wires are passed through insulated connections
permanently set air-tight in the retorts, but other well known means of applying
electricity may be adopted such as are used for decomposing bodies. The object
here is that inasmuch as the power or influence of electricity is very great in
decomposing bodies, so it will in this Invention be especially useful in conjunction
with heat and a vacuum. But in practice I should prefer to use what is called or
known as thermo or thermal electricity, not only on account of its greater power,
but of the facility which exists in its application to such a case as this, where it is
desirable to avoid unnecessary complication, and the attendance requisite to keep up
a supply of ingredients. Moreover the necessary heat would be at hand for the
general development of thermo electricity, and there would be no risk of the battery
getting out of order, or other suitable means of generating and applying electricity
may be adopted. Therefore as soon as the vacuum is established the heat and
electricity would simultaneously be brought to bear on the contents of the retorts,

page_text: and a complete disorganization and decomposition would ensue, but I do not wish
it to be understood that I propose necessarily to use electricity in conjunction with
a vacuum, as I propose to work also with a vacuum alone. Now let it be considered
what would take place under the former principle of the Invention with or without
the aid of the latter; first, the easily eliminated products would be freed from the
coal, then by degrees the further series, and so on until a general elimination of the
gaseous and volatile products would occur, regulated or limited however by the
reduced degree of heat, and especially is this limitation to be borne in mind in so
far as sulphurous impurities are to be regarded, because it is well known that
sulphur elimination is promoted by excessive temperature in the retorts, whereas
by this Invention excessive temperature is avoided and sulphur controlled. What-
ever of liquid residues would be converted into vapour or gas would follow their
natural order, and the remainder of the liquid residues would flow to the reservoirs
or remain in the carbon residue with sulphur and other impurities not capable of
being eliminated or driven off at low heats. It is not however necessary to dwell
further on this subject so long as the rationale of the process is explained. Now
, although the treatment of the residues is an after consideration I desire to explain
that the carbon residue may not properly be what is termed coke, it will be a
residue of carbon and impurities, such as sulphur capable of further treatment. I
however propose to deal with it in any of the following ways:-I propose if
necessary to burn it in coking ovens and convert it into coke, or else to make it
into artificial fuel by compression with other suitable materials used for that purpose;
or I may deal with it in many other ways; I may mix it with the liquid residues
and other materials for fuel, and it would thus become available where ordinary
coke cannot be used. It is however certain that in this Invention nothing is lost as
nothing is burnt up and destroyed, and therefore whatever the coal may contain (be
it cannel or other coal) its elements will be reproduced in other ways, i.e., in gas and
in solid and liquid residues, and since by the low heat employed the sulphur will
scarcely be eliminated at all, an immense saving will be effected in the troublesome
and imperfect purification of gas. A greater quantity must be produced and a
quality of high illuminating property, burning a pure light and giving off no
deleterious sulphurous fumes as is at present the case.
Moreover a vast saving in
labour and in charging and discharging the retorts will inevitably result. What-
ever further apparatus may be necessary as used in gas making need not be dwelt
upon here, as it would form no part of the Invention.
I have mentioned coal as being used in the retorts, but of course if desired other
substances or materials may be used, such as shale, or the refuse from oil works, or
indeed any others that may be suitable for yielding hydrogen and carbon, although
in no case do I propose to use mineral oils.