Improvements in the Method of Working Blast Furnaces.
Year: 1890

page_text: Date of Application, 22nd Jan., 1890
Complete Specification Left, 21st Oct., 1890-Accepted, 6th Dec., 1890
PROVISIONAL SPECIFICATION.
Improvements in the Method of Working Blast Furnaces.
THOMAS TURNER of 217 Ladywood Road Birmingham, in the County of Warwick,
Lecturer on Metallurgy, do hereby declare the nature of this invention to be as
follows:-
In the ordinary method of working a blast furnace large quantities of combustible
gases pass out of the top of the furnace. These gases which consist essentially of
carbon monoxide carbon dioxide and nitrogen are sometimes allowed to burn and
are in this way wasted, but they are now more generally utilized for heating the
blast and for raising steam. My invention has for its object the better utilization
of these gases so as to economise fuel in the blast furnace. For this purpose I
draw off a portion of the gases say about one third of the whole though I do not
restrict myself to this proportion. The waste gas so obtained is caused to pass
once more through the blast furnace by being forced in under pressure either
around the hearth of the blast furnace or at such higher level as may be found
best suited to the conditions of any particular furnace. The waste gases may be
used either in their ordinary condition or may be heated before being passed again
into the furnace. They may be forced in either by a steam injector by the blast
being used as an injector by force pumps or by other suitable means.
The object
of thus introducing the gases is to save fuel owing to the chemical reaction
CO₂+ C = 200
2
taking place the result being that only one half the amount of carbon is used to
produce one part of carbonic oxide as is the case at present.
This economy can however only he carried to a certain limit as beyond that point
the temperature of the furnace would be unduly lowered. It will be understood I use
ore flux and fuel as is at present universally done but using part of the gases over
again I save part of the fuel hitherto necessary and thus an important economy is
effected.
Dated this 21st day of January 180n
THOMAS TURNER.
COMPLETE SPECIFICATION.
Improvements in the Method of Working Blast Furnaces.
I THOMAS TURNER of 84 Wellington Road, Edgbaston, Birmingham in the County
of Warwick, Lecturer on Metallurgy 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
--
My invention has for its object an improvement in the method of working blast
furnaces so that less fuel may be used than has been employed heretofore and that the
waste gases from such blast furnaces may be more fully utilized.
In the ordinary method of working a blast furnace large quantities of combustible
gases are produced and pass out of the top of the furnace. These gases contain
carbon monoxide, carbon dioxide and nitrogen, and when smelting iron with coke
usually contain at least two volumes of carbon monoxide to one volume of carbon
dioxide. These gases were formerly allowed to burn at the top of the furnace and
were thus wasted, but are now generally utilized for heating the blast and raising
steam though usually more gas is produced than can be so used.
In carrying out my invention I draw off the waste gases from the furnace by the
Prina 17

page_text: methods which are in common use and employ as much as may be required for heating
the blast, raising steam, and other similar purposes, as is the usual custom.
The rest of the waste gases which may amount to one third of the whole though I
do not restrict myself to any proportion I cause to pass once more through the blast
furnace. For this purpose I force the gases into the blast furnace under pressure and
at such height as is found most suitable to the conditions of any particular furnace.
A convenient method of carrying out my invention is to deliver the waste gas
through the ordinary twyers the pipes attached to which are very simply and
inexpensively modified so as to cause the high pressure blast to force the waste gas
into the furnace. This is accomplished by breaking joint in the blast pipe a short
distance from the furnace and allowing the blast to pass for the remaining distance
through a wider pipe than is at present used. The nozzle of the blast pipe enters a
short distance into the wider pipe, while waste gas is delivered into a suitable space
around the mouth of the wider pipe. Such a form of injector is familiar to engineers.
Suitable flap or other valves may be used to prevent any danger of explosion in case
the nose of the twyer should get accidentally closed.
The waste gases may also be forced into the blast furnace by a suitable pump or
pumps, or by the use of injectors with steam. But a fan is unsuitable for this
purpose as the pressure produced is usually insufficient. The gases may be heated if
desired. The object of thus introducing the waste gases into the furnace is to save
fuel in accordance with the following chemical reaction
CO₂ + C = 200.
One part of solid carbon thus produces two volumes of carbon monoxide instead of
only one volume as at present. But the carbon dioxide which is thus reduced is
usually accompanied by at least twice its bulk of carbon monoxide which is at the
same time rendered available for the reduction of the ore in the furnace. The result
is therefore that one part of solid carbon produces four volumes of available reducing
gas instead of only one volume as at present.
This economy can however only be carried to a certain moderate limit which varies
in different furnaces, as beyond that point the temperature of the furnace would be
unduly lowered. For this reason I prefer to use the blast as hot as possible so as to
counteract any tendency to cool the furnace. I do not alter the shape of the furnace
in any way, nor change the present method of drawing off and utilizing the waste
gases. Nor do I claim the use of any other gases than the residue of unused waste
gas as above described. I do not enrich this gas in any way, and my invention is not
applicable to a cupola furnace.
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 introduction of blast furnace gases into the ordinary iron blast furnace sub-
stantially in the manner and for the purposes herein set forth.
Dated this 18th day of October 1890.
THOMAS TURNER.