A METHOD OF MANUFACTURING ILLUMINATING GASES
Year: 1867

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough Park,
Brixton, in the County of Surrey, for the Invention of "A METHOD OF
MANUFACTURING ILLUMINATING GASES:"A-communication from abroad by
William Elmer, residing at the City; County, and State of New York,
United States of America.
COMPLETE SPECIFICATION filed by the said George/Tomlinson Bousfield
at the Office of the Commissioners .of. Patents with his Petition, and
Declaration, on the 16th May 1867, pursuant to the. 9th Section of the
.:Patent Law, Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUBFIELD, of Loughborough Park, Brixton, in the County of
Surrey, do hereby declare the nature of the said Invention for "A METHOD
or MANUFACTURING ILLUMINATING GASES," (a communication to me from abroad
by William Elmer, a person resident at the City, County, and State of
New York, United States of America,) and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
In order that this Invention may be 'more clearly understood it is deemed
necessary to present some facts in regard to the ordinary method of manufac-
turing 'illuminating gas." In the manufacture of illuminating gas by the

page_text: ordinary method many reactions and chemical changes occur, which depend
to a great extent upon the temperature to which the gas material is subjected,
for example, when gas coal is distilled at the lowest temperature at which the
coal gives off gases and vapors the weight of coke or carbonaceous substance
left in the retorts is much less than when subjected to a high heat, consequently
the amount of carbon remaining combined with hydrogen is sufficient to form
condensable hydrocarbon vapors, coal oil, and the complex substance known
as coal tar, while a small quantity of gas only is produced. On the other hand
the higher the heat employed the greater is the quantity of gas produced, and
the greater also is the weight of carbonaceous substance left in the retorts, and
the smaller therefore is the amount of carbon combined with the hydrogen
contained in the products given off, which are chiefly light carburetted hydrogen
volatile hydrocarbon vapors, carbonic acid, and carbonic oxide. The coal in
all cases contains a large surplus of carbon over the quantity required to
combine with the hydrogen to form gaseous compounds of the two, and yet
the gases produced by a high heat are always deficient in carbon, the very
substance on which the light depends. Now it has long been known that in
making gas in the ordinary way as the process advances and the temperature
of the retorts and their contents become elevated less tar and condensable
bydrocarbon vapors are formed, and a mixture of gases and volatile hydrocarbons
which possess more equally the proper proportions of carbon and bydrogen
necessary to form a good light is produced. But as the process advances
the carbon in the gaseous mixture begins to diminish from the decomposition
of olefiant gas and volatile hydrocarbons, and the carbon these contain to a
great extent is deposited in the retorts and stand pipes in the form of crysene,
pyrene, paranaphthaline, and free carbon or soot, while the hydrogen, especially
as the temperature becomes still more elevated soon appears greatly in excess
of the carbon until carbonic oxide and light carburetted hydrogen are produced
in abundance; and, lastly, free hydrogen only is given off from the coke left,
all non-illuminating agents. The results produced by both the high and low
extremes of temperatures are valueless to the gas manufacturer, as they
constantly tend to one or other of two narrow extremes, both wasteful with too
high heat; an excess of diluents is produced which thins the gaseous mixture
and deprives it of carbon with too low heat, an excess of tar and other
condensable hydrocarbons is produced, these are constituted mainly of the two
essential elements of illuminating gas, hydrogen and carbon, and are entirely
lost, so far as the production from them of gases is concerned, although these
substances amount to fully one-half of the products of the coal. Gas coal
subjected to an uniform medium temperature, were it possible to maintain

page_text: such a temperature, would, not even then be productive of economy. The
volume of gases produced would be larger than under a low heat, but much
less than the volume produced by the high heat; with the gases evolved by a
medium temperature would also be produced hydrocarbon vapours, some of
which remain with the gases produced and are a variable source of their
luminosity when burned, but the greater proportion of these hydrocarbon
vapors would be condensed and wasted in the process of washing the gas,
while other hydrocarbons would form the substance known as coal tar as-
under a low heat, though not to the same extent.
In the ordinary process of gas making where a charge of several cwts. of coal,
often in large lumps, is thrown into an ignited retort it is impossibie to
maintain an uniform temperature, the heat is conducted very gradually to the
interior of the mass of coal, while the exterior portion becomes highly heated,
and therefore various portions of the charge are exposed to very unequal tem-
peratures, especially in the earlier stages of distillation. The natural and
inevitable consequences of this condition are. the production of a gaseous
mixture of very poor illuminating power, and a waste of the very best light
giving material by conversion into substances, which according to the
uncontradicted testimony of every one who has examined the subject hold
as much illuminating matter as exists in the gases finally obtained. The
quantity of gas manufactured, by any process depends upon the volume of
hydrogen evolved from the gas material employed, if we except the presence
of carbonic oxide, and the luminosity of the gas depends upon the amount of
carbon combined with the hydrogen or conveyed by it to the flame. When
we therefore consider that in all cases gas stock whether it be coal, oil, or
bituminous matter in any other form, invariably contains an excess of carbon
over the hydrogen it is certainly evident that the hydrogen contained in the
tar and in the other condensable hydrocarbons is just so much waste in the
volume of gas which should be obtained. There are also other elements in
some kinds of gas material which go still further in appropriating hydrogen.
Thus, a portion of the hydrogen contained in gas coal uniting with the oxygen
present produces water, some of the hydrogen unites also with a portion of the
sulphur present, forming sulphuretted hydrogen, and again a portion of the
bydrogen combines with the nitrogen present, producing ammonia. Thus a large
quantity of the hydrogen contained in the gas material is appropriated to the
formation of other compounds than illuminating gases; this fact also explains
the reason of the formation of coal tar and the other condensable hydrocarbons
instead of illuminating gases.. If all the hydrogen present in the gas material
were to unite with its corresponding equivalents of carbon. in the required
-

page_text: proportions of these two elements to form some definite gaseous compound
there would be no formation of tar or other condensable hydrocarbons, but
gas and coke only would be formed as far as these two elements are concerned.
It is not suprising then that so many efforts should have been made to supply
to the carbon an additional quantity of hydrogen from some extraneous source,
as in the "water gas" process. If we examine what really takes place in the
process of manufacturing illuminating gases in the ordinary way we will find that
a considerable portion of the hydrogen contained in the coal is appropriated to
the formation of aqueous vapor which is disposed of in two ways, a portion of
it is decomposed by the red hot carbon present forming carbonic acid, carbonic
oxide, and hydrogen, while the greater portion of it is condensed into water
and passes off by the bydraulic main. Why then introduce more steam into the
retorts when they are constantly giving-off water? The source of carbonic
acid and carbonic oxide in coal gas is the decomposition of aqueous vapor
by carbon and not a direct union of oxygen with carbon. The oxygen present
exists principally in the coal; a small proportion is also derived from the
atmosphere in charging the retorts. The oxygen of the atmosphere introduced
into the retorts would unite directly with the carbon; then as the oxygen
exists in the gas coal it must necessarily be present in manufacturing gas
from coal. The question is how to dispose of the oxygen so as to prevent the
great waste of hydrogen with which it combines to form water. The con-
densable hydrocarbons obtained from the coal operated upon contain no oxygen.
The formation of aqueous vapor takes place under all temperatures from
that sufficient to decompose the coal, to the highest heat to which it is
subjected, but the greater proportion is formed simultaneously with that of
the condensable hydrocarbons, which however are very irregularly given off
when a large mass of coal is introduced suddenly into heated retorts. The
practice of throwing a large quantity of coal into heated retorts, as is usual in
gas works, is attended with great disadvantages. In the first place, the tempe-
rature of the retorts is inimediately lowered so that a large quantity of fuel is
*necessarily expended in again raising the temperature to the degree of heat
essential to the process of distillation; and, in the second place, the products of
'distillation are for the most part complex heterogeneous substances,. no
'uniformity in the character of these products can be obtained under such
circumstances, while the losses attending these results are considerable, and at
the same time the products are not of the character desirable. Moreover, the
quantity of poisonous gases and vapors and particles of carbon or soot constantly
permeating the atmosphere of gas houses is very great, and consequently
-destructive to health. To sum up then in a general way it may be stated, 1st,

page_text: that the ordinary methods of manufacturing what are called "illuminating
gases" are neither productive of economy nor gases of a satisfactory character;
and, 2nd, the manufacture is a great nuisance in all cities and towns where the
gases are made, and noxions not only to the operators, but also to the public
health. To obviate these objections and at the same time produce a gond arti-
ficial light so as to cheapen one of the prime necessities of life constitute the new
system of gas manufacture which is the subject of this Patent, and the modus
operandi of which is as follows:-An ordinary bench consisting of the usual
number of retorts or any number desirable may be employed. The retorts
are D shape, and arranged in a bench in the usual way, but instead of only
one mouth piece to each retort there are two, one attached to either end:
The stand pipe is situated at the back end of each retort instead of the front,
as is usual in gas works; to each of the front mouth, pieces is attached an
upright supply pipe which terminates in a rotary valve; the front mouth
piece contains a slide or piston, to this slide is attached a rod protruding
through a stuffing box in the lid of the mouth piece. To the under side of
the mouth piece on the opposite end of each retort is attached a discharge pipe
or tube which is made to dip into, a reservoir of coal tar or, other suitable
liquid; a valve should be placed in the mouth piece above the reservoir, and
covers when closed the upper and open end of the discharge tube. This valve
is only designed as a convenience to close the retort when the process is not
in operation or in case of repairs.
For illustration of this description reference is made to the accompanying
Drawings which form a part of this Specification.
The gas coal is introduced in small charges and at intervals into the supply
tube through the rotary valve which is made' gas-tight, and as the valve
rotates a certain quantity of coal drops into the front mouth piece, and is
-carried or pushed forward by the slide (which is operated by the projecting rod)
into the heated retort, which is maintained: at a full red heat, or a heat
approaching to whiteness, according to the character of the material subjected
to the process. As each.charge of fresh coal is pushed forward by the slide
the previous charges already in the retort are progressively advanced in it,
and the one that is farthest from the charging end is ejected and permitted
to drop through the discharge pipe or tube into the reservoir. The gas
contained in the chambers of the valve taken up from the tube as the valve
rotates is displaced by exhaustion and discharged into the main leading to the
gas holder. The coal occupying each retort is composed of four equal parts
which have been charged into it in succession; -as the first part of the coal (or
that at the charging end) approaches the heat the volatile products begin to

page_text: and hydrogen; the latter element in the act of its liberation from the aqueous
vapor is so exalted as to instantly combine with a portion of the carbon in the
volatile products, forming a definite hydrocarbon gas, while the volatile products
also partaking in the reactions are converted into illuminating gases. A very
small electric spark passed through this mixture of gases and carbon-vapours
causes the hydrogen instantly to unite with the latter in the combining
proportions to form some definite compound. This effect is due to the direct
exaltation of the chemical affinities of these bodies induced. by the action of
electricity. Only that portion of the coal that has been deprived of volatile
products, and is brought to a full red heat is capable of decomposing water;
hence only a portion of the aqueous vapor formed in the ordinary process of
gas making is decomposed, while by the new method the aqueous vapor is
brought directly in contact with the coke, and by the additional aid of
electricity the decomposition is not only rapid and complete, but involves also
the decomposition of a portion of the carbonic acid. When water is decomposed
by highly heated carbon out of contact with the air an electric current is produced,
the vapor of water becoming the electrolyte, and is decomposed by the hot
charcoal, just as the water in an ordinary voltaic couple is decomposed by the
zinc, so that the charcoal becomes charged with - E, and the aqueous vapor
and carbonic acid with + E. Chemical action is always accompanied by
disturbánce of the equilibrium between the molecules of a body, and may
therefore be expected to give rise to electric excitement. It is true that
if the whole of the aqueous vapor formed in the process of gas making be
decomposed, there would be an increase of carbonic oxide remaining with
the gases formed, but, on the other hand, there would also be a large
volume of bydrogen appropriated to the formation of illuminating gases.
About fifty per cent. more of illuminating gases is made by the new method
than by the ordinary process, while the gases have also a higher illuminating
power, from the fact that both acetylene and olefiant gases are produced by this
method, and in much larger quantities than by the ordinary process. Again
the amount of gases and volatile hydrocarbons that are lost in the ordinary
way of charging the retorts is by no means a small item. The loss from
each bench of retorts has been estimated at an average of a hundred cubic
feet every time the. charges are withdrawn and the retorts again charged.
This estimate which is probably too low would amount to 600 cubic feet.
of gases from each bench in twenty-four hours, provided the retorts were
always charged every four hours which is the ordinary rule. At this rate in
all large gas works a loss of several thousand cubic feet. of gases occurs every
twenty-four hours

page_text: 1. Dy tuist
material are converted into permanent illuminating gases and etherial
hydrocarbons, hence no tar or other condensable hydrocarbon is formed.
2. Fully fifty per cent. more gases from a given quantity of material is made
by this system than by the ordinary process, while the luminosity of the gases
is much superior.
3. The gases do not deteriorate like ordinary coal gas, hence there is no
condensation of volatile bydrocarbons in the purification of the gases nor in the
holder or mains.
4. The new method of gas manufacture is not confined to bituminous
coal, but any one of the great variety of other hydrocarbons may be used, most
of which abound quite as much weight for weight in elements convertible
into substantially the same illuminating gases as those obtain from the best
cannel coal, and some of them still more so among the valuable material of
this nature, being all forms of bitumen, asphaltum, rock oil, or petroleum,
the latter when mixed with woody fibre in the formn of sawdust and also when
mixed with peat produces most brilliant illuminating gases.
5. An uniform temperature is easily maintained, and the expense for fuel
is much less than in the ordinary process, while the advantages of charging
and discharging the retorts in the manner described are that it requires much
less manual labor, as the whole process can be worked by machinery, and at
the same time the retort house may be kept perfectly cleanly, wholesome, and
free from poisonous gases, vapors, and carbon or. soot.
•
The Invention is not limited to the particular forms of the supply valve slide
and retorts, as these may be varied as found expedient.
.
What I claim as the Invention and desire to secure by Letters Patent is,―
First, the combination of the gas making retort with a supply valve (for
the introduction of the gas material), and with a slide (to move the said material
forward in the retort), substantially as set forth.
Second, the combination of the gas making retort with a discharge tube
terminating in a reservoir of liquid which prevents the entrance of air or the
escape of gas, and permits the residuum of the gas material to be removed
without opening the retort, substantially as set forth.
Third, the progressive method or process of manufacturing gas, substantially
as herein-before set forth, consisting in moving the gas material forward at
intervals in the retort.
Fourth, the method or process, substantially as herein-before set forth, of

page_text: decomposing the gas material in a heated retort in presence of a current of
electricity..
Fifth, the combination of the gas making retort with a battery in such
manner that a current of electricity is caused to operate upon the gaseous
matter evolved in the retort from the gas material, substantially as set forth.
In witness whereof, I, the said George Tomlinson Bousfield, have hereunto
set my hand and seal, this Sixteenth day of May, in the year of our Lord
One thousand eight hundred and sixty-seven.