The Ohio Democrat. (Logan, O. [Ohio]) 1886-1906, 1888-08-25
HOW GAS IS MADE.
An Explanation OF the Details which Com
plicate the Really Simple Process.

INV WAC 10 mAO6s
An Exploration Of the DETAILS which Com.
piicate tho Really Simple Process.
The principle Of gas manufacture Is
very simple, but there are many prac-
tical details which complicate the actual
process. 1t depends upon the fact that.
when bituminous coal containing car
bon and hydrogen is subjected to heat
in n retort, it is partially decomposed,
giving Off gaseous hydrocarbons and
other products, and leaving behind
mass OF carbon commonly known as
coke. But many other compounds are
formed ut the same time, which must
be separated from the gas before it is
fit to be sent into the pipes, and deliv-
cred to the consumer. The products
OF the distillation of coal may be divi-
ded roughly into four classes-coke,
coal-tar, ammoniacal liquor and illum-
mating gas. Coke contains from ninety
to ninety-five per cent. Of pure carbon.
the remainder being ash and sulphide
of iron. The ammoniacal liquor con-
tains at least five different salts OF am
monia. The coal-tar contains about
forty different liquid and solid hydro
carbons, and the illuminating gas twen-
ty-fve or more gaseous hydrocarbons
"a total of over seventy distinct
chemical substances, all produced
by the distillation of apiece OF soft coal.
1t must be remembered that few or
none Of these exist by themselves in
the coal, but are all formed by the
chemical reactions which take place
during the distillation. The retorts
in which the coal is distilled are
made either of cast-iron or fire-clay;
they are about nine feet long and
one and half feet in diameter.
After being filled with coal, they are
raised to red heat, or even higher.
The impure gas thus formed passes off
through an upright pipe, which oon-
meets with horizontal one partly
| filed with water, known us the hydrau-
| lie main. The pipe from the retort dips
under the water, so that all the gas
must pass through it. The coarser and
less volatile impurities, including a
large proportion Of the tar, are con-
densed in this main. The gas, however,
is still at high temperature, and very
| impure; SO it is sent through Il set of
vertical pipes connected with each
other like steam radiator, which are
either exposed to the air, or cooled
artifcially. Many of the impurities
are condensed and separated from the
gas in the cooler, but it is sometimes
still further purified by being passed
through large iron vessels filled with
Jumps OF coke over which stream of
cold water is constantly flowing. This
| still further purifies the gas, especially
by absorbing the ammoniacal COM
pounds; but the offensive and danger
Gus sulphur compounds remain. and to
| remove these the gas is sent through
large iron boxes containing movable
trays covered with moist, freshly
| Stacked lime. The lime absorbs the
greater part Of the compounds of sui
phur, and the gas is then ready
to be stored in the large holders,
improperly called gasometers, and
from thence delivered to the GUS
toner. After absorbing the i'm
purities, the gas-lime, as it called,
possesses most horrible odor, and in
thiclly settled localities its disposal
without creating a nuisance is an i'm
| portant and sometimes a difficult mat
ter. A more effective and simpler
means OF purifying gas is much to be
desired. What is known as wuter-gas
has been substituted to some extent for
that distilled from coal. 1t is essen
TALLY mixture of hydrogen and car
bonic oxide, and is formed by curious
reaction which takes place when steam
is passed over red-hot Goals. The steam
is decomposed, and hydrogen is set
free, while the oxygen unites with the
carbon OF the coal to form carbonic
oxide (CC). AS this gas burns with a
| non-luminous flame, it must be zen.
riched" with light-giving hydrocar-
bons, which are usually obtained from
the Installations OF crude petroleum. 1t
is claimed that this gas is much cheaper
than that produced by the old process
but practical trials have not as yet con-
firmed this, and the presence of the
highly poisonous carbonic oxide rem
ders it much more dangerous agent
to introduce into dwellings. s.-Populay
Science NeaOs.