Improved Method of and Apparatus for Recovering Chemicals from Solutions, or when Mixed with Substances which are Volatilizable or Destructible by Heat, Especially Adapted for Recovering Soda from Waste Liquors of Pulp Digesters.
Year: 1889

page_text: Date of Application, 31st Dec., 1889-Accepted, 8th Feb., 1890
COMPLETE SPECIFICATION.
Improved Method of and Apparatus for Recovering Chemicals from
Solutions, or when Mixed with Substances which are Volatilizable
or Destructible by Heat, Especially Adapted for Recovering Soda
from Waste Liquors of Pulp Digesters.
We MORTIMER BLAKE MASON, SAMUEL DENNIS WARREN and FISKE WARREN,
all of 220 Devonshire Street, Boston, in the State of Massachusetts one of the
United States of America, Merchants 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 :-
This invention relates to a novel method and apparatus for recovering chemicals,
such as alkalies, alkaline earths, and other substances, from solutions, or when mixed
with substances which are volatilizable or destructible by heat, our improved method
being especially adapted for recovering soda from the spent or waste liquors of pulp
digesters.
The waste or spent liquors referred to contain or hold in suspension substantially
large quantities of carbonaceous matter, such as resins, gums, etc., extracted from the
wood, straw or other like material by the soda solution employed in the manufacture
of pulp.
In accordance with our invention, the spent liquor is preferably evaporated to a
consistency of about 35° Beaumé in any suitable form of evaporating apparatus.
The partially evaporated liquid is next introduced into the combustion chamber of
a furnace of any desired construction, through an atomizer, as will be described.
The combustion chamber is preferably heated substantially to an incandescent heat,
so that the carbonaceous matter, fed into the said chamber with the atomized spent
liquor, may be consumed.
The gases generated by the consumption of the carbonaceous matter referred to,
may be conducted to a condenser or wash tower, where any soda carried off from the
combustion chamber thereby, may be recovered, the said gases preferably impinging
upon a boiler located in the furnace to heat water therein to generate steam.
The soda thus freed from carbonaceous matter, which constitutes the chief impurity
thereof, collects upon the floor of the combustion chamber in a substantially fused
liquid condition, and may be discharged therefrom through a suitable door or tap,
preferably into wagons, by which it may be conveyed to the cooling room.
The particular features in which our invention consists will be pointed out in the
claim at the end of this specification.
Fig. 1 shows in section and elevation a sufficient portion of an apparatus embodying
our invention to enable it to be understood, the furnace being shewn in section,
and
Fig. 2, a side elevation of the furnace shown in Fig. 1, looking toward the right.
The furnace A of brick or other suitable material, is divided, as herein shown,
by a substantially horizontal wall A¹ into two chambers b, 61, connected by a
passage b².
The chamber 6', as herein shewn, contains a boiler c of any desired or suitable style
or type, in which steam may be generated, it being provided with the usual appur-
tenances, such as pressure gauge 20, water gauge 21, safety valve 22, etc.
The chamber b, constituting the combustion chamber of the furnace, has commu-
nicating with it, as shown, pipes a herein shewn as three in number, the said pipes
constituting inlet pipes for the said chamber.
Each pipe a, as shown, has connected to it pipes a¹, a², a³, provided with suitable
cocks a, the pipe a' being connected to a steam supply, (it may be the steam dome or
-space of the boiler c) the pipe a* to an oil supply, not shown, and the pipe a'

page_text: preferably to an evaporating chamber in which the spent liquor is condensed to
about 350 Beaumé.
The pipes a, a, a³, are connected together, as herein shown, to the pipes a and
constitute the atomizer of our apparatus, by which the spent liquor is injected into the
chamber 6 in substantially a finely divided state or spray, but we do not desire to
limit our invention to this particular form of atomizer as any other form of atomizer
or arrangement of pipes by which the spent liquor is sprayed or finely divided, may
be used.
In operation, the chamber bis first preferably heated substantially to the point of
incandescence by oil supplied by the pipe a² or in other suitable manner.
The cock at of the pipe a³ is now opened to admit the partially evaporated spent
liquor, which is atomized or injected into the chamber 6 by preferably super-heated
steam, admitted into the pipe a through the pipe a¹, the cock at in the pipe a' being
opened.
с
The carbonaceous matter contained in the spent liquor is consumed in the chamber b,
and the gases thus generated pass into the chamber b¹ by passage 62, the said heated
gases after impinging upon the boiler c and generating steam therein, finding an exit
through a pipe d connected to a condenser or wash tower e, the said gases in the
condenser or wash tower e, as herein shewn, being subjected to a spray of water,
issuing from a pipe f connected to a suitable source of supply, and by which any soda
carried over may be condensed or washed out of the gases passing therethrough, the
resulting liquid being carried away as shown by the pump D.
The consumption of the carbonaceous matter maintains the temperature of the
furnace b substantially at the point of incandescence, so that after the chamber 6 has
been once heated, the oil or other source of supply may be cut off, but if desired, the
oil may be admitted with the super-heated steam through the pipe a² to assist in the
combustion of the carbonaceous matter.
The soda injected into the chamber 6 strikes the walls thereof, which are preferably
circular or concaved, so that the soda in substantially a fused or liquid condition may
flow toward a duct or channel 63 leading to the outlet door or tap d thus facilitating
removal of the fused soda from the said chamber.
If it is desired to recover the soda in the form of black ash, that is with part of
the carbon remaining unconsumed, a grate d¹º rocked or made movable by a lever d²,
or in any suitable manner, may be located above the floor of the combustion
chamber, and the soda collected upon the said grate, and sifted therethrough, as
desired, the said soda not being exposed to the heat sufficiently long to burn off all
the carbon, or the temperature of the furnace being maintained somewhat below the
incandescent point.
Instead of using super-heated steam to inject the spent liquor into the combustion
chamber, we may employ compressed air or other gas.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1: The method of recovering chemicals, which consists in injecting in a combustion
chamber as spray a mixture containing the chemical to be recovered and burning said
mixture as fuel, substantially as described.
2-The method of recovering chemicals, which consists in injecting the chemical
into a combustion chamber, burning said chemical as fuel, and then separating the
floating chemical particles from the gaseous products of combustion, substantially as
described.
3: In a furnace for the recovery of chemicals, a combustion chamber, an atomizer
consisting of a liquid inlet pipe connected to the supply of chemical to be recovered,
and a steam and oil pipe connected to said inlet pipe, whereby the chemical mixed
with oil is discharged into the combustion chamber in a finely divided state, and the
carbonaceous matter contained in the said chemical liquor is consumed, substantially
as described

page_text: 4 In a furnace for the recovery of chemicals, a combustion chamber, an atomizer
consisting of a liquid inlet pipe connected to the supply of chemical to be recovered,
and a steam pipe connected to said inlet pipe to discharge the chemical into said
combustion chamber in a finely divided state, substantially as described.
5: In a furnace for the recovery of chemicals, a combustion chamber, and a boiler
located in said furnace, an atomizer consisting of a liquid inlet pipe connected to the
supply of chemical to be recovered, and a steam pipe communicating with the said
boiler and connected to the said liquid pipe, to discharge the chemical into said
combustion chamber in a finely divided state, the said boiler being heated by the
combustion of carbonaceous matter contained in the said chemical, substantially as
described.
6: In a furnace for the recovery of chemicals, a combustion chamber, and a boiler
located in said furnace, an atomizer consisting of a liquid inlet pipe, and a steam
pipe communicating with the boiler and connected to the said inlet pipe to discharge
the chemical into said combustion chamber in a finely divided state, and with a
condenser or wash tower connected to said furnace, whereby the gases are freed from
the chemical, substantially as described.
7: In a furnace for the recovery of chemicals, a combustion chamber, a feed pipe
to supply the chemical, and an oil pipe connected to the said feed pipe, substantially
as described.
8: In a furnace for the recovery of chemicals, a combustion chamber, an atomizer
or burner communicating with the said chamber and connected to the supply for said
chemicals, and a condenser or wash tower connected to the said furnace, to operate,
substantially as described.
Dated the or
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicants.