Improvements in Coking Processes and in the Manufacture of Coke and in the Recovery of Products.
Year: 1892

page_text: Date of Application, 17th Sept., 1892
Complete Specification Left, 1st Dec., 1892-Accepted, 7th Jan.. 1893
PROVISIONAL SPECIFICATION.
Improvements in Coking Processes and in the Manufacture of Coke
and in the Recovery of Products.
I JOHN BOWING of Tilbury in the County of Essex Consulting Chemist do
hereby declare the nature of this invention to be as follows:-
The methods of coking in bee hive ovens and closed retorts commonly adopted
hitherto have been found to be defective when applied to many varieties of coals
some of which cannot be coked at all in any sort of oven.
Now I have discovered that the process of coking successfully depends to a great
extent upon the method in which the heat is applied.
A coking action in all cases is due to heat and success in coking both as regards
the quality of the coke and the economy of production depends upon the regulation
of the heat and on the manner in which the materials are heated.
If the whole mass of the coal which is to be coked be rapidly raised to a
coking temperature in the usual manner the coke produced will be poor and in the
case of many coals which are usually said to coke badly, no coke, or at all events
a worthlesss coke will be produced.
But if the arrangement of the coking oven be such that the heat can be caused
to travel gradually through the mass so that the coking action is commenced near
to the source of heat and is set up in the more remote parts as the heat travels
progressively through the mass, excellent coke may be produced from coals which
would fail to coke altogether in the ordinary beehive oven. I may illustrate this
by assuming the coal to be coked to be in the form of a sphere and the heat to be
generated in the centre of the sphere. The heat so generated will travel outwards
in all directions radially from the centre and almost the whole mass will coke
perfectly whereas the same coal treated in a beehive oven would fail to coke.
In practice I have found that it is desirable to have the source of heat in the centre
of the mass and this may be conveniently effected by means of two concentric
cylindrical chambers the inner one of small diameter being the chamber in which
the heat is generated and the outer one of large diameter being the chamber in
which the material to be coked is placed. The heat generated in the inner
concentric vessel travels outwards through the surrounding coal which is being
coked and a comparatively cool layer of the material surrounds the zone where the
coking action is going on.
With such an apparatus I have produced excellent coke in large quantities from
coals which can hardly be coked at all in the common coking ovens as now used
and the very high temperatures which are commonly used are not only unnecessary
but may be undesirable.
I attribute considerable importance to the existence of a comparatively cool zone
beyond the zone where the coking action is going on and also to the gradual travel
of the heat outwards. It appears to me to be very probable that these two con-
ditions exercise an important control over the volatile products which in ordinary
ovens are driven off and pass away almost as soon as they are formed.
The shape and dimensions of the oven may be varied in a great variety of ways
provided that the arrangements are such that the heat is caused to travel gradually
through the mass and so as to have a comparatively cool zone of material in front
of it.
Dated this 16th day of September 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in Coking Processes and in the Manufacture of Coke
and in the Recovery of Products.
I JOHN BOWING of Tilbury in the County of Essex Consulting Chemist do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
The methods of coking in bee hive ovens and closed retorts commonly adopted
hitherto have been found to be defective when applied to many varieties of coals
and there are some varieties of coal which cannot be coked at all in any sort of
oven.
Now I have discovered that the process of coking successfully depends to a great
extent upon the method in which the heat is applied and allowed to travel through
the mass and that certain forms of apparatus are extremely well adapted for
carrying out my invention.
A coking action in all cases is due to heat and success in coking both as regards
the quality of the coke and the economy of production depends upon the regulation
of the heat and on the manner in which the materials are heated.
If the whole mass of the coal which is to be coked be rapidly raised to a coking
temperature in the usual manner the coke produced will be poor and in the case of
many coals which are usually said to coke badly, no coke or at all events a worth-
less coke will be produced.
But if the arrangement of the coking oven be such that the heat can be caused
to travel gradually through the mass so that the coking action is commenced near
to the source of heat and is set up in the more remote parts as the heat travels
slowly and progressively through the mass excellent coke may be produced from
coals which would altogether fail to coke in the ordinary beehive oven or in the
common closed retort. I may illustrate this action by assuming the coal to be coked
to be arranged in the form of a sphere and the heat to be generated or applied
in the centre of the sphere. The heat so generated will travel slowly outwards in
all directions radially from the centre and almost the whole mass will coke
perfectly whereas the same coal treated in a beehive oven will fail to coke.
In practice I have found that these conditions are very effectually secured by
means of two concentric cylindrical chambers the inner one of small diameter
being the one from which the heat comes and the outer one of large diameter
being the chamber in which the material to be coked is placed from which the air
is excluded. The heat from the inner concentric vessel travels outwards through
the surrounding coal which is being coked and thus a comparatively cool layer of
the material always surrounds and is immediately adjacent to the hot zone
where the coking action is going on and this cool zone in its turn becomes the
coking zone and is in its turn surrounded again by a comparatively cool mass outside
of it as the heat travels outwards. These conditions can be secured in vessels or
ovens of a variety of shapes.
With such an apparatus I have produced excellent coke in large quantities from
coals which can hardly be coked at all in the common coking ovens as now used
and the very high temperatures which are commonly used are not only unnecessary
but may be undesirable.
I attribute very considerable importance to the existence of this mass of com-
paratively cool coal beyond the zone where the coking action going on whatever
may be the shape of the vessel in which the coking action is being conducted and
also to the gradual travel of the heat outwards. It appears to me that these two
conditions may exercise a most important control over the coking action in the
following manner. The effect of the cool mass may be that the distillation
products which are formed in the hot or coking zone are arrested instead of being

page_text: allowed to pass off or being burnt off as in the usual forms of coking apparatus and
are thus kept in contact with the coal which is actually coking and may thus play
a part in the coking action which they cannot play if allowed to escape freely
and the effect of allowing the heat to travel gradually through the mass is to
ensure the existence of a cool mass immediately beyond and adjacent to each hot
zone as it is formed.
The actual rate at which the heat must be allowed to travel through the mass
will in all cases depend upon the materials which are being operated on and this
rate can in all cases be determined by one or two trials.
No better general guide can be given than the statement that it must be made to
travel gradually and this is a condition which is attained with certainty when the
heat is generated in a small internal tube.
I have found that coal which cokes comparatively well in ordinary ovens may be
formed into most excellent coke in this manner and that coal which cannot be made
to coke in ordinary ovens in any way such as South Wales steam coals may be
coked in this manner if it be mixed with a small proportion of some coking coal.
For example I have in this manner coked South Wales steam coal mixed with
from 25 to 30 per cent. of coking coal without any difficulty. This process may
also be very advantageously adopted in coking coal and blue billy and other ores
and substances when mixed according to the invention for which I have obtained
Letters Patent No. 11083 dated 30th June 1891.
What I claim as my invention is :-
1. The method of coking substantially as described.
2. Coking in such a manner as to cause the heat to travel gradually through the
mass either substantially radially or otherwise so that a mass of coal shall be kept
in a comparatively cool state for a considerable time in contact with or adjacent to
the hot zone or layer of coal which is actually coking.
3. In coking retaining the products of distillation within the mass by means of a
comparatively cool mass of the material being coked.
4. In coking causing the heat to be communicated to the mass at practically
speaking one point so as to travel gradually outwards through the mass and radially
from that point.
5. Coking by means of apparatus consisting of an internal supply of heat sur-
rounded by the coal to be coked.
JOHN BOWING.