IMPROVEMENTS IN APPARATUS FOR RECOVERING SODA ASH FROM WASTE LIQUORS CONTAINING THE SAME
Year: 1880

page_text: LETTERS PATENT to Alfred Chapman, of the Firm of Fawcett, Preston, and
Company, of Liverpool, in the County of Lancaster, Engineers, for an Invention
of "IMPROVEMENTS IN APPARATUS FOR RECOVERING SODA ASH FROM WASTE
LIQUORS CONTAINING THE SAME.”
"
PROVISIONAL SPECIFICATION left by the said Alfred Chapman at the Office
of the Commissioners of Patents on the 12th March 1880.
ALFRED CHAPMAN, of the Firm of Fawcett, Preston, and Company, of Liverpool,
in the County of Lancaster, Engineers. "IMPROVEMENTS IN APPARATUS FOR
RECOVERING SODA ASH FROM WASTE LIQUORS CONTAINING THE SAME.”
"
My Invention relates to apparatus for recovering soda ash from waste liquors
containing the same, and more particularly the waste liquors run from the vessels
in which esparto has been boiled for making paper pulp. As a very large quantity
of water has to be evaporated in proportion to the soda ash recovered, economy in
the fuel used for effecting the evaporation and the subsequent incineration of the
material so as to obtain the ash is of great importance.
My improved apparatus consists of (1) a steam generator placed or set so that
steam may be generated either by its own proper furnace or by the heat from the
burning off furnace hereinafter described; (2) a set of multiple effect vacuum pans
arranged, by preference, horizontally; (3) a condenser and vacuum engine of any
suitable construction; (4) a burning off furnace into which the liquor when
sufficiently treated in the vacuum pans is run, and in which it is ignited, and then
keeps burning till the ash is produced; (5) a series of tubes arranged in the burning
off furnace so as to heat the waste esparto liquor on its way from the supply tank
to the donkey pump; (6) a donkey pump for feeding the steam generator with the
esparto liquor.
The working of the apparatus is, therefore, as follows:-The waste liquor flows
from the supply tank into and through the tubes-in-the-burning off furnace, and
being heated therein goes to the donkey pump; the donkey pump forces it to the
steam generator; the steam from the generator passes to the first pan of the
multiple effect pans and evaporates the liquor therein; the steam evaporated in
this pan goes to the second pan to evaporate the liquor in this pan, and so on

page_text: through the set of pans if three or more be used, the vacuum engine keeping up the
proper degree of vacuum in each of the several pans. When the liquor has been
sufficiently treated in the pans it is run into the burning off furnace, where it is
ignited and burnt as already stated.
The pans may be supplied with liquor either from the generator, or from the
donkey pump, or direct from the supply tank.
The vacuum engine is driven by the steam produced in the generator, so that the
power required for producing the vacuum is obtained by the evaporation of water
from the liquor. The exhaust steam from the engine is carried to the multiple
effect pans, and so evaporates its proportion of water.
Instead of an injection condenser an open surface condenser may be applied,
over which the mother liquor may be passed, and so obtain another effect.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Alfred Chapman in the Great Seal Patent Office on the 11th
September 1880.
ALFRED CHAPMAN, of the Firm of Fawcett, Preston, and Company, of Liverpool,
in the County of Lancaster, Engineers. "IMPROVEMENTS IN APPARATUS FOR
RECOVERING SODA ASH FROM WASTE LIQUORS CONTAINING THE SAME."
My Invention relates to apparatus for recovering soda ash from waste liquors
containing the same, and more particularly the waste liquors run from the vessels
in which esparto has been boiled for making paper pulp. As a very large quantity
of water has to be evaporated in proportion to the soda ash recovered, economy in
the fuel used for effecting. the evaporation and the subsequent incineration of the
material so as to obtain the ash is of great importance.
My improved apparatus consists of (1) a steam generator placed or set so that
steam may be generated either by its own proper furnace or by the heat from the
burning off furnace hereinafter described; (2) a set of "multiple effect" vacuum
pans arranged, by preference, horizontally; (3) a condenser, which may be an
injection condenser, but is by preference a surface condenser; (4) a vacuum
engine of any suitable construction; (5) a burning off furnace into which the liquor
when sufficiently treated in the vacuum pans is run, and in which it is ignited, and
then keeps burning till the ash is produced; (6) a series of tubes arranged in the
flues of the burning off furnace so as to heat the waste esparto liquor on its way
from the supply tank to the boiler; (7) a donkey pump for feeding the steam
generator with the esparto liquor.
Figure 1 of the annexed Drawings is a longitudinal section, and Figure 2 a
horizontal section of an apparatus constructed according to my Invention.
"
A is a tank to receive the liquor to be treated and supply it to the surface
condenser when such is used, or to the donkey engine; B is the surface condenser ;
C, a tank to receive the liquor which passes over the surface condenser; D, a pipe
to convey the liquor from the tank Ċ to the donkey engine; E is the donkey.
engine for feeding the steam boiler; F is the steam boiler; G, the vacuum engine;
H, I, J, are respectively the first, second, and third vacuum pans of a "triple effect'
apparatus; the number of these pans may be varied as thought desirable; K. is the
burning off furnace; L, L, are raking forward doors; M is a raking out door; N is
the fire mouth of the burning off furnace; O, an auxiliary fire mouth for the steam
boiler; P, a chamber for cooling the recovered ash; Q, a pipe connecting the
tank C with the first vacuum pan H; R, R, is a system of tubes forming a support
to the brickwork of the flues through which tubes the liquor is pumped, and so
heated on its way to the boiler; S is a damper to allow the waste heat from the
furnace to pass to the boiler; T, T, are dampers to enable the furnace to be used
independently of the boiler.
The working of the apparatus is as follows:-
The liquor from the supply tank A is allowed to flow by suitable canals over the
horizontal tubes forming the surface condenser B into the tank C, from which it is
removed by the donkey pump E and pumped into the boiler F which supplies the
steam cylinder of the vacuum engine G, and when necessary any of the three vacuum
pans, the connections to which are not shown in order not to complicate the
Drawing. Q is a pipe for conveying the liquor from the tank C to the first of the
series of vacuum pans H, I, J, in the case when water is used in the boiler, but if
the-liquor-is-used-in-the boiler-then the pan H-receives-its-supply from-the-boiler
itself. The exhaust steam from the vacuum engine G passes into the interior of the
heating tubes in the first pan H and causes the liquor in that pan to boil and give
off vapour. This vapour passes into the heating tubes of the second pan I, causing
the liquor therein to boil and give off vapour, which in turn passes into the heating

page_text: tubes of the third pan J, producing a like effect on the liquor therein contained;
the vapour given off by the third pan passes into the surface condenser, where it is
condensed, at the same time that an amount of water is evaporated from the liquor
passing over the tubes of the condenser equal to the vapour condensed inside them.
Thus, for one evaporation in the boiler I obtain one in the first pan, one in the
second, one in the third, and one in the surface condenser; each evaporation may
be less in practice than the amount indicated by theory, but in practice I have
found the arrangement to be economical. From the third pan the liquor is
extracted at a suitable density (I prefer 60° Twaddel, 1300 to 1350 specific gravity)
and fed into the end of the burning off furnace. In this furnace it thickens
immediately and takes fire, aided by the coal fire N, and in the course of a few
hours it is ready to be raked out by the door M, having in the meantime been
stirred up from time to time by means of the raking forward doors L.
When so treated the noxious vapours usually perceptible when reboiling the
spent liquors from straw and esparto boilers are entirely suppressed or consumed,
and the recovered ash is raked into the chamber P, where it can be stored until
required for use.
By means of my improved apparatus great economy of fuel is effected, first,
because the waste heat from the burning off furnace is used for producing steam in the
boiler; secondly, because the liquor itself is used in the boiler for producing steam,
and one evaporation from it is thus effected; thirdly, by the use of the multiple system
of vacuum pans, well known in the manufacture of sugar from cane and beetroot,
in conjunction with the surface condenser, by which means no injection water is
needed, at the same time that another evaporation is obtained that would otherwise
be lost or not effected. Another advantage resulting from the use of my improved
apparatus is the absence of noxious smells and of drainage of all refuse matter by
which streams are polluted, as no refuse matter is formed, the water being distilled
from the liquor and the magma remaining being consumed until only the soda ash
remains. I may remark that sometimes the spent or waste liquor, especially that
which has been used for boiling straw, primes to such an extent that it is more
advantageous to forego the economy obtained by evaporating it in the steam boiler
and to use ordinary water in the boiler; in this case, by a simple arrangement of
cocks and connections, as will be readily understood, the donkey engine supplies
the boiler with the condensations from the first pan, which acts as a surface
condenser to the vacuum engine; the exhaust from the cylinder of the said engine
always going to the coils or tubes in the first pan is therein condensed. If liquor
is being used in the boiler the condensations are run away; if however water is
used in the boiler the condensations are returned to the boiler by the donkey
engine through the heating pipes R, or the liquor from the tank C can be passed
through the pipes R so as to become heated on their way to the first pan. The other
operations with the liquor take place in the way already described.
4
Having now described the nature of my said Invention, and in what manner the
same is to be performed, I declare that I claim,-
The combination of parts arranged and working substantially as hereinbefore
described and shown in the annexed Drawings, and forming an improved apparatus
for recovering soda ash from waste liquors containing the same.
In witness whereof, I, the said Alfred Chapman, have hereunto set my hand
and seal, this Tenth day of September, One thousand eight hundred and