Process of and Apparatus for Obtaining Glycerin and other Products from Soap Makers' Spent Lyes.
Year: 1894

page_text: Date of Application, 26th June, 1894-Accepted, 28th July, 1894
COMPLETE SPECIFICATION.
Process of and Apparatus for Obtaining Glycerin and other Products
from Soap Makers' Spent Lyes.
We, JOSEPH VAN RUYMBEKE, of No. 78 Wall Street, in the City of New
York, County of New York and State of New York, United States of America,
Chemist, and WILLIAM FREDERICK JOBBINS, of No. 78 Wall Street, in the
City of New York, County of New York and State of New York, United States
of America, Manufacturing 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 :-
This invention relates to a process of and apparatus for obtaining glycerin and
other products from soap makers' spent lyes. In carrying out this process we
make use of the apparatus illustrated in the drawings, in which,
Figure 1, represents a section, partly in elevation, of that portion of the plant
used to treat the lyes previous to evaporation.
Figure 2, a similar view of the salt washer and drier:
Figure 3, a front elevation of the evaporators;
Figure 4, a similar view of the stills:
Figure 5, a top elevation of the catch-all drums of the stills, and.
Figure 6, a front elevation of the concentrators.
The essential points of novelty in the process and apparatus will appear from the
detailed description together with the appended claims.
In the course of salting out closed soap by means of common salt there is
obtained a sub-lye containing common salt, water, glycerin, nitrogenous and some
other impurities. The separated soap still carries impurities and is therefore closed
again and again salted out, and this process is repeated until a soap stock of
sufficient purity is obtained.
In the course of salting out, the sub-lye first obtained is generally used to salt
out fresh batches of soap to increase its percentage of glycerin. In this way
sub-lyes containing varying degrees of glycerin and impurities are obtained, the
most impure of which are called "rosin lye" "niger" or "niger lye."
In the recovery of glycerin from soap lye as usually practised, the very dark
and impure lyes are allowed to run to waste. By this process we recover the
glycerin from all of the various sub-lyes, so that no liquors are allowed to run to
waste from the soap kettle.
We will now describe the apparatus used to carry out this process. Referring
to Figure 1, A, represents a series of connected settling tanks, in place of which
may be used a single settling tank A', divided into compartments. Next to the
settling tank is the liming tank D, which is connected with the mixing tanks E
and F. H, is a filter press supplied with material from the mixing tanks E and F,
through suitable piping by means of the pump H¹. G, is a tank to receive the
filtrate from the filter press H, said tank being connected with the tank K, where
the lye is heated and supplied with a solution of caustic soda when needed, said
tank K, being connected with the filter press M. L, is a tank to receive the
filtered liquor from the filter press M, said tank being also provided with a heating
coil. I, is a tank in which the filter cake from the filter press H, is mixed with
water, such mixture being subsequently passed through the filter press H. The
mixing tanks E, F, and K are supplied with perforated pipes for blowing air
through the liquids to keep them agitated during the process of mixing.
Referring to. Figure 2, U, is a washer, V, is a rose in the washer, X is the cover
of the washer, Y, is a receiver communicating with the washer, and Z, is a vacuum
pump connected with the receiver Y. U¹ is a false bottom or screen within the

page_text: :
บ
washer. is a pipe connecting the bottom of the washer with the cylinder Y, and
¹ is a valve in said pipe.
Referring to Figure 3, 1 and 2, represent cylindrical evaporators made of sheet
iron, 3, 3, are vertical posts or pillars arranged in pairs and of the proper height,
and 4, 4, are supporting braces at the top of said pillars for supporting the
evaporators 1 and 2. 5 and 6 are circular heads or flue sheets within the
evaporator 1,. and 7, 7, are flues connecting said heads. 8 is a steam inlet pipe for
admitting steam into the space between the heads 5 and 6, which space constitutes
a steam drum, said pipe having a valve 9, and 10 is an outlet pipe for condensed
steam from said space, having a valve 11. 12 is a water gauge or column on the
outside of the evaporator connected with the steam drum, for measuring the amount
of water of condensation therein.
13, is a man hole or door in the lower part of the evaporator for removing the
salt or other deposits therefrom, and 14 is a similar door in the evaporator about
two thirds of the way from the bottom thereof, to allow the interior of the
evaporator to be reached for the purpose of cleaning the same. 15, 15 are
draw-off pipes provided with valves 16, 16, and connected with the pipe 17. We
make use of two or more of these pipes arranged one above the other, in order that
the liquid may be drawn off close to the upper layer of the salt deposited in the
evaporator.
18, is a gate valve at the bottom of the evaporator for drawing off the contents
thereof for any desired purpose. 19 is a vacuum draw-off pipe connected with the
interior of the evaporator above the maximum limit of the deposited salt. 21 is a
valve in the pipe from the evaporator which connects with said pipe 19. By
opening the valve 21, a portion of the liquid in the evaporator may be run out into
the pipe 19, after which the valve 21 is closed and the valve 22, is opened and the
small quantity of liquid in the pipe 19, is removed and may be tested.
In this way
a sufficient quantity of liquid in the evaporator may be drawn out for the purpose
of testing, against the vacuum therein and without affecting such vacuum.
23, is a water gauge on the side of the evaporator and connected therewith for
determining the height of the liquid therein. 24, is a steam gauge on the front
or side of the evaporator, connected with the steam space between the heads 5
and 6, for deterinining the pressure therein, and 25, is a vacuum gauge for indicating
the extent of vacuum in the evaporator. 26 is a pipe leading into the evaporator,
by means of which lye, not saturated with salt, may be introduced into the
evaporator for the purpose of dissolving out any salt which may accumulate in the
flues 7 and around the same, and thereby prevent incrustation thereof. Such lye
should be allowed to be in contact with the pipes to be cleaned for a sufficient
length of time to dissolve the incrusting matter. 27, is a pipe with valves opening
into the evaporator above the steam drum therein for introducing the material to
be evaporated. 28 is an annular plate within the evaporator near the top thereof,
strengthened by braces 29 and having the hole or opening 32, at its central part.
30 is a circular dash plate of larger diameter than the opening 32 and supported
directly beneath the same by rods 31. This latter dash plate serves to prevent in
a great measure any of the material from being projected from the evaporator in
case of a sudden application of vacuum or steam heat.
33, is a heavy vapor pipe leading out from the evaporator and provided with a
gate valve 34, therein. 35, is a pipe from the evaporator 2, provided with a gate
valve 36 therein, the latter being arranged above the pipe 33, so that any material
from the evaporator .1 will be prevented from entering the evaporator 2.
37 is an annular dash plate and 38 is a circular dash plate secured beneath the
same. These elements correspond to those in the evaporator 1.
39 is a man hole for entering the evaporator 2. 40 is a steam drum, 41 a steam
gauge connected therewith, 42 a water gauge or column for determining the amount
of water of condensation in the steam drum 40, 43 is a vacuum gauge and 44, a
water gauge for determining the height of the liquid in the evaporator.
45, is a vacuum draw-off pipe on the evaporator 2, corresponding to the pipe 19,

page_text: of the evaporator 1. 47 is a door at the lower part of the evaporator 2, for
removing the salt and other sediments that may be deposited therein. 48, 48 are
draw-off pipes for removing the contents of the evaporator 2, close to the salt
therein, connected with the pipe 49 and provided with valves 50. 51 is a draw-off
pipe corresponding to the draw-off pipe 18 of the evaporator 1. 53, is a steam
pipe for admitting steam into the steam drum 40, and 52 is a pipe for removing
the water of condensation therefrom. 54 and 55 are pipes on the side of the
evaporator 2, for introducing the material therein. 56 represents the continuation
of the pipe 33, leading into the catch-all 57. Within this catch-all 57 is a pipe 58,
its upper end being open and arranged with its opening above the upper level of
the pipe 56, passing down through the bottom of the catch-all 57 and counected
with the drum 60. 59 is a draw-off pipe provided with a valve therein for removing
the condensed liquid material entrained or mechanically carried off with the
distillate that may be deposited in the catch-all 57. The catch-all 57 is provided
with a removable head and with a water gauge 571 for determining the amount of
material that may be caught by and deposited within the same. 60 is a horizontal
cylindrical drum beneath the catch-all 57, and connected with the pipe 58, as
before stated. This drum 60 is provided with a water gauge 61, for indicating the
amount of condensed water therein. 62 is a pipe extending up from the top of the
drum 60 and connected with any desired form of vacuum pump. 63 is a draw-off
pipe for removing the contents of the drum 60, either into a tank placed beneath
said drum or to any desired receptacle. The drum 60 on which rests the catch-
all 57 is supported on the standards 64 by means of lugs or brackets 65, bolted to
the tops of said standards and to the drum 60.
Referring to Figure 4, 66 is a reheater made preferably cylindrical in shape
of iron or of steel; and 67 is a still. The heater 66, and still 67 are vertically.
arranged side by side as shown. 68, 68 are pillars or posts having the braces
or I-beams 71, secured at the top thereof. The heater 66, and still 67 are
supported on these braces by means of lugs or brackets 97, bolted to the same.
72, is a steam pipe from a boiler or any suitable source of steam supply. This
pipe 72 connects with the steam pipe 73, running parallel midway between the
heater and the still, and provided at its lower end with the enlarged. cylindrical
chamber 74, for receiving the water of condensation from said pipe."
Beneath this chamber 74 is a valve 75, for removing the water of conden-
sation. 76 is a small steam pipe connected with the pipe 73, above the
chamber 74 and provided with a valve 77 therein. The steam pipe 76 enters
the heater 66, near the lower part thereof and connects with steam coil 78 in
said heater. This steam coil 78 is preferably made of pipe of considerably
larger diameter than the steam pipe 76, so that the steam from the pipe 76 on
entering the coil 78 will rapidly expand therein, its temperature being corre-
spondingly reduced. Instead of this arrangement it is obvious that the steam
pipe 76 may be of the same diameter as the steam coil 78 or even larger, and
that the valve 77 may be so adjusted as to allow the steam to expand into the
steam coil 78, in the same way.
The steam coil 78 is supported within the heater 66 by means of braces 78',
arranged vertically in the heater. The upper end of the coil 78, which I shall
hereafter refer to as the "expansion coil" connects with the pipe 80, which passes
out through the side of the heater and enters the still 67, being provided at its
lower end with a distributing ring or pipe 81, having perforations therein pre-
ferably extending downwards for injecting steam into the contents of the still.
82 is a pipe extending out from the pipe 72, and provided with a valve 83 therein,
said pipe 82, entering the top of the heater 66. 84 is a pipe at the bottom of the
heater 66, provided with a valve 85 therein for removing water of condensation
from the heater. 86, is an asbestos or other insulated covering around the heater 66,
in order that the heat of the same may be retained without loss by radiation.
87, is a draw-off pipe provided with a valve for removing the contents of the
still when desired. 89, is a door in the lower part of the still, provided with a

page_text: valved pipe 90, for removing the sediment and residue from the still. 91, is a
water gauge or column on the still 67, for determining the amount of material
therein. 92, is a pipe branching out from the steam pipe 72, and having a valve 93,
therein. This pipe 92, connects with a steam coil 94 within the still for heating
the contents thereof.
88, is a valved steam pipe connected with the lower end of the coil 94, for
carrying off the steam or condensed water therefrom. 95 is a pipe having valves 96
for introducing the material into the still. The still may be provided with a dash
plate if desired, arranged in any suitable way.
98, is a pipe for carrying off the distillate or vapor from the still 67 which pipe
connects with the upper end of the drum 69. 100 is a pipe connecting the upper
end of the drum 69, with the upper end of a similar drum 70 arranged at the side
of the drum 69, both of these drums being supported on the braces 71 by means of
the saddles or, brackets 99. 101 are pipes leading out from the bottom of the
catch-all drums 69 and 70, and provided with valves 102 therein. The pipes 101,
connect at their lower ends with the pipe 103, which enters the side of the still and
which is provided with a valve 104. 105 is a pipe connected with the pipe 103
which enters the side of the still and which is provided with a valve 106 therein.
107 is a tank beneath the pipe 105. Instead of making use of two drums, as
described, it is obvious that only one drum, or two or more drums, may be
employed.
a
Extending up from the top of the drum 70, is a vertical pipe 108, provided with
a horizontal branch pipe 109, at its upper end. This pipe 109 connects with the
upper end of the upright cylindrical condenser 114. Within this condenser are the
heads or drums 110 and 112, connected together by tubular flues 111. 113, are
pipes leading into the top and out of the bottom of the space formed between the
heads 110 and 112 for maintaining a circulation of water or other cooling agent
therein. 115 is a pipe leading out of the lower end of the, condenser 114 and
connected with the receiving drum 116. This receiving drum 116 is provided with
a water gauge 117 thereon, for determining the amount of condensed distillate
therein. The said drum is also provided with a draw off pipe 118, having
valve 119 drawing off the condensed distillate. A tank 120 placed beneath the
receiving drum 116 may be used for receiving this distillate. The receiving
drum 116 and also the condenser 114 are supported on pillars or posts 121 by
means of lugs or brackets 122, bolted to the tops of said pillars and to the side of
said drums. Referring to Figure 6, 123 represents a concentrator made preferably
either of iron or of steel. This concentrator 123 is supported on pillars or
posts 124, by means of brackets or lugs 125, bolted to said concentrator and to
braces 116, connecting the tops of the said posts. 127 is a steam pipe provided
with a valve 128 having a steam gauge thereon, for registering the amount of
pressure in the pipe. This pipe connects with a steam coil 129 within the concen-
trator for heating the contents thereof. 130, is a steam pipe having a valve therein
for carrying off the condensed steam from the coil 129. 131 is a water gauge or
column on the side or front of the concentrator 123 for indicating the height of the
material therein. 132 is a vacuum draw-off pipe connected with the concentrator 123,
at one or more levels, and provided with valves 133, 134, for drawing material into
said pipe 132, from any desired portion of the liquid in the concentrator.
135 is a
valve beneath the pipe 132 for removing the material drawn therein for the purpose
of testing the same. 135 is a pet cock at the top of the pipe 132 for admitting air
into the same.
136 is a draw-off pipe at the lower end of the concentrator for removing the
concentrated material therefrom. 137 is an annular dash plate within the con-
centrator near the top of the same and provided with a circular dash-plate 138
supported beneath the plate 137, by means of rods 139. 140 is an opening in the
aunular plate 137 above the circular dash plate 138, but of smaller diameter than
the same. 141 is a pipe from the concentrator 123 for carrying off the aqueous
vapors and other volatile matters therefrom and provided with a valve 142

page_text: This pipe 141 is connected with a catch-all 143, provided with a pipe 144 therein,
having its upper open end arranged above the opening of the pipe 141. 145 is a
water gauge for indicating the amount of liquid that may be caught by and
retained in the catch-all 143. 146, represents the continuation of the pipe 144, and
which connects with the top of the drum 147 provided at one of its ends with a
water gauge 148.
149 is a draw-off pipe for removing the contents of the drum 147, provided with
a valve 150. 151, 151 are pillars or posts on which the drum 147 is supported by
means of lugs or brackets 152, bolted to the top of said pillars or posts and to said
drum. 153, is a pipe which leads out from the bottom of the catch-all 143 at one
side of the pipe 144 and is connected with a horizontal pipe 154, by means of a
four way casting as shown, to enable the pipes 153 and 154 to be cleaned.
The pipe 154 enters the side of the concentrator 123, and is provided with a
valve 154 therein. 155 is a valved pipe entering the pipe 154 between the
concentrator and the valve 154¹ in said pipe for introducing the material into
the concentrator.
156 is a second concentrator provided with a steam pipe 157; having a valve 158
therein, and with a steam gauge 159 thereon. This steam pipe 157, connects
with a coil 160 on the inside of the concentrator 156. 161 is a water gauge on
the concentrator, and 162 is a vacuum draw-off pipe connected therewith and
having the valves 163, 163. 164 is a draw-off pipe for the concentrator 156 and
having the valve 165, and 166 is a steam pipe connected with the end of the coil 160
for carrying off the steam therefrom, or for removing the water of condensation
therein. 167, is a pipe having valves 168 for introducing material into the.
concentrator 156. 169 is an annular dash plate near the top of the concen-
trator 156, provided with a circular dash plate 170, supported by rods 171, as
before explained. 172 are pillars or posts for supporting the concentrator 156,
by means of lugs or brackets 174 bolted to the braces 173 and to said
concentrator.
17 is a pipe for carrying off the aqueous vapor from the concentrator 156 and
provided with a valve 176 which pipe 175 connects with the. catch-all 143. In
practice it is desirable that the concentrator 156 which concentrates the glycerin
after the second distillation should be made of copper, preferably tinned on its
interior, in order that there may be no danger of contaminating or discoloring the
glycerin.
In carrying out this process, the sub-lye is first run into the compartment B, of
the settling tank A, or into the first tank B', if the series of connected settling
tanks A is used. When using a single tank the compartments are so connected
that the liquid flows from one compartment at a distance of about one-third of the
way from the bottom to the next compartment. By this arrangement the sediment
which is deposited accumulates in the bottom of the first compartment or in the
first tank B when the tanks A' are used, while the greater part of the soap will
rise to the top of and float on the liquid therein, whence it may be removed from
time to time and will often be found to be of considerable value, as it may be
added to the batches of the subsequent soap boiling. This preliminary clarification
is made more effective by allowing the sub lye to cool to about 120° F. in the
settling tank, whereby the soap will separate more quickly and thoroughly at the
top and the suspended material will also be more quickly deposited as a sediment,
which sediment is removed by valved pipes at the bottom of the compartments.
After this preliminary clarification, the liquid is drawn from the last compartment
if a single tank is used, or from the last tank when a series of tanks is used, as in
this way both the clearest and coolest portion of the settled lye is obtained. From
the settling tank or tanks the sub lye is passed into the liming tank F, where it is
partially clarified by the addition of slaked lime. The quantity of lime added for
this purpose need not be closely limited. We may state that a quantity of
lime varying from one quarter to two pounds of lime calculated as calcium

page_text: monoxide (CaO) will generally be found suitable for the treatment of one hundred
gallons of sub lye.
After the lye has been introduced into the mixing tank, it is analysed for caustic
and carbonated alkali the alkali which is combined with rosin and fatty acids not
being included, such determination being readily effected in the ordinary way by
means of a standard acid, phenol phthalein being used as an indicator. After the
percentage of caustic and carbonated alkali has been determined, ferric sulfate is
added in quantity sufficient to neutralize such free alkalies within two to six
ihundredths of one per cent. of the total alkalinity. The amount of ferric sulfate
needed having been thus determined, it is dissolved in hot water, added to the sub
lye and thoroughly mixed therewith in the mixing tanks E and F; tubs E' being
provided in which the ferric sulfate is dissolved. After this operation, the lye
is passed through the filter press H, by means of the pump H', generally cold;
but when the lye is rich in glycerin it is necessary to heat it; heating coils
(not shown) being provided for the purpose in the mixing tanks, because the
ferric hydrate and ferric soap formed by the reaction partly remain dissolved
in the cold, although they do not redissolve after having been heated and
precipitated. The cake in the press is generally steamed before removing it so
as to wash out its contained glycerin. For this purpose steam is supplied to the
filter press H, by means of a valved pipe h. Sometimes, and especially when
abundance of exhaust steam is available for evaporation, the filter cake obtained
from the first filtration is mixed with water in the tank I and the mixture is
.filtered so as to ensure a more complete recovery of the glycerin.
The liquid coming from the filter press is generally almost white and clear, but
sometimes, through a defect in one or more of the filter cloths, it shows some
turbidity. Besides, it always contains in solution certain salts of iron, such as
and mainly ferric acetate. If it were concentrated in this condition the sodium
chlorate or common salt obtained would be contaminated by the suspended insoluble
.matter not separated in the filter press and by the ferric hydrate or basic ferric
-acetate precipitated by the decomposition of the ferric acetate and other decom-
posable ferric salts. To avoid this, the lye is conducted to the tank K, heated to
the boiling point by the steam coil in said tank, and if necessary to precipitate
the iron completely, a small yet sufficient quantity of caustic soda is added.
After such precipitation, the lye is passed through the filter press M, whence it
will issue perfectly clear into the tank L, and is ready for evaporation.
We have discovered that in evaporating these lyes the first salt which separates
after the salting point has been reached consists essentially of sodium sulfate,
-often to the extent of eighty per cent., the remaining twenty per cent. consisting of
.sodium chloride or common salt. Therefore, when it is desired to manufacture
glauber salt, or to obtain the sodium chloride or common salt as free as possible
from the sulfate, the evaporation is stopped when most of the sulfate has separated,
and the crude sulfate thus obtained is purified by solution in water and crystal-
lization, such operation being repeated, if necessary, until sufficiently pure glauber
.salt is obtained.
After the separation of the impure sodium sulfate as above described, the
evaporation of the liquid is continued until it reaches a density of 28° Beaume
as drawn from the evaporator, or thirty degrees Beaume at fifteen degrees C.
Where the evaporation of the sodium sulfate is not desired, the evaporation may be
carried on to this point continuously from the beginning. At the above described
density (30° Beaume at 15° C.) the lye contains about fifty per cent. of glycerin and
most of the salt originally contained therein has been separated. The evaporation
above described, although capable of being performed in an open vessel, is
preferably carried on in a vacuum evaporator, such as shown in Figure 3, of the
drawings. This lye is introduced into the evaporator 1, through the pipe 27. We
then close the valve 36, so as to maintain a fairly high vacuum, preferably, say,
about twenty inches within the drum 60 and catch-all 57 and evaporator 1. Steam

page_text: is now introduced through the pipe 8, into the steam drum of the evaporator and
heats the flues 7, and the heads 5 and 6 to the proper temperature. This beat.
should be sufficient to concentrate the lye until it has been concentrated to the
proper degree, preferably to about twenty eight degrees Beaume when drawn from:
the evaporator, or thirty degrees Beaume at fifteen degrees C. as stated. This.
heating may be conveniently accomplished by means of exhaust steam.
By means of the pipe 19, the specific gravity of the lye may be tested from time.
to time, and when it has reached the desired strength, preferably that indicated,.
the lye is drawn off as closely as possible to the salt through one of the draw-off"
pipes 15. By making use of the annular and circular dash plates 28 and 30, the
liquid is prevented from being injected into the pipe 33, by any sudden increase of
the vacuum or steam heat.
At the above described density, (thirty degrees Beaume at fifteen degrees C.)
the lye contains about fifty per cent. of glycerin and most of the salt contained therein.
has been deposited. The salt which has thus been deposited in the evaporator 1,.
is removed therefrom through the door 13, while still hot and is introduced into.
the shallow tank N, which, as before explained, is provided with a false screen U',..
a couple of inches above the bottom thereof, said false bottom being preferably
covered with a coarse cloth. After the salt has been placed in this shallow tank
and leveled, connection with the cylinder Y is established by opening the valve
of the pipe v. In this way most of the lye adhering to the salt is removed by
suction produced by the vacuum in the cylinder Y, and the salt becomes fairly dry.
in a few minutes. After all the adhering lye, removable by suction, as above
described, has been separated from the salt, the cover X, carrying a helical per-
forated pipe, or the rose V, is put on the tank, and steam is admitted from any
suitable source of supply by opening the valve u, the vacuum pump Z being also set
in motion. The jets of steam from the perforated pipe or rose V, strike the upper-
layer of the salt and steam is drawn through the salt in a more or less condensed.
form, whereby the salt is washed and thus further purified, after which it is ready
for the soap house. The liquid passing from the shallow tank U, to the cylinder Y,..
is transferred from the latter to any desired point by gravity, suction or other
means, but preferably to a second concentrator, or to a still. After the lye has.
been evaporated to the proper specific gravity, it is removed through one of the
draw-off pipes 15, into the evaporator 2, this removal being generally accomplished
by the suction of the high vacuum therein. The concentrated lye, having a density
of thirty degrees Beaume at fifteen degrees C. as before stated, is now subjected to.
a second concentration in the evaporator 2, by means of steam introduced into the
steam drum 40, until the lye has attained a specific gravity of thirty four degrees
Beaume at fifteen degrees C. An additional quantity of salt separates during
this operation, which salt may be removed and dried in any suitable way. The
reason for carrying on the evaporation process in two steps, as above described,..
is that when the salt is impregnated with concentrated crude glycerin, it is..
difficult to dry and to free from its adhering mother liquor, but by evaporating it
in the first evaporator until it reaches a specific gravity of not more than thirty
degrees Beaume at fifteen degrees C. as before explained, we are enabled to free-
it of most of the salt originally contained therein.
By carrying on the evaporation in a vacuum of about twenty-six to twenty-eight
inches, and with steam at a low pressure, the loss of glycerin by evaporation is.
reduced to a minimum and in fact there is practically no loss of glycerin from this
source when the process is properly carried out.
A sufficient quantity of the concentrated lye is now introduced into the still 67,.
through the pipe 95, preferably by reason of the vacuum therein. We now close.
the valve 96 and maintain the vacuum in the still, and steam is introduced through
the pipe 72 and passing through the pipe 92 into the steam coil 94, heats the
contents of the still up to a temperature approximating the boiling point thereof
at the vacuum used. Steam from the pipe 72 also passes through the pipe 82,
into the heater 66, and heats the expansion coil 78 therein to the proper-

page_text: temperature. Steam from the pipe 72, also passes through the pipe 73, into the
smaller pipe 76 and thence into the large expansion coil 78, where it rapidly.
expands, its temperature being reduced corresponding to the extent of expansion.
By heating the expansion coil 78 by means of free steam in the heater 66, the
expanded steam in such expansion coil will be reheated approximately to its
original temperature and in its expanded and reheated form will pass through the
pipe 80 and be injected into the material through the perforated pipe or ring 81.
By first allowing this steam to expand and by then reheating it before injecting it
into the liquid, we find that expansion in the still in the presence of the vacuum
used is reduced to a minimum. This injected steam, at a temperature of about
300 F. at a vacuum of twenty eight inches or more, in passing through the liquid
will rapidly distill the same and the distillate passes out through the pipe 98 into
the drum 69. The less volatile distillate, comprising glycerin, generally of an
excellent quality will be deposited in the drum 69. From the drum 69 the distillate
passes by means of the drum 100 into the drum 70 and more glycerin will be
condensed and retained therein. The more volatile distillate, consisting of glycerin
with a large percentage of watery vapour passes up from the drum 70 by means of
the pipe 108 and enters the condenser 114, where it is condensed by passing through
the cooling pipes 111. The condensed distillate will now be deposited in the
receiving drum 116. The sweet water thus collected in the receiving drum 116,
may be removed therefrom into the tank 120, after the distillation has ceased, or by
stopping the vacuum pump. The less volatile distillate collected in the drums 69
and 70, which as before mentioned, is concentrated glycerin, generally of a bright
color and of an excellent quality, may be drawn out of said tanks into the tank 107
through the pipes 101, 103 and 105 but if upon test it is found that this glycerin is
not of sufficient purity, it may be returned through the pipes 103, into the still by
opening the valve 104.
The distillate in the tank 120 is now ready for the first concentration in the
concentrator 123, which may be an iron concentrator. The valve 176 is closed so
as to cut off the concentrator 156 and a vacuum is maintained in the concentrator 123
by means of a vacuum pump connected with the receiving drum 147. By thus
maintaining a vacuum in the concentrator, the glycerin from the receiving tank 120,
may be drawn through the pipe 155 by suction, or by any other suitably located
pipe. Steam is now admitted into the coil 129, through the pipe 127 and the
glycerin is maintained at a temperature above the boiling point of water at the
vacuum used.
The watery vapour thus driven off passes through the pipe 141 and enters the
catch-all drum 143. This watery vapor generally carries with it small and varying
quantities of glycerin. The watery vapor and glycerin passing into the catch-all
will impinge against the pipe 144 and the glycerin contained in the vapor will
condense and deposit in the drum 143. The watery vapor thus driven off passes
into the pipe 144 and accumulates in the receiving drum 147, from which it may
be removed as desired.
The glycerin which is condensed in and collected by the catch-all drum 143,
by reason of the fact that it is of a less volatile nature than the watery vapor
passing through the same, may be returned to the concentrator 143, by the
pipe 154, by opening the valve 154' therein. When the glycerin has been
sufficiently concentrated, which can be determined by means of the pipe 132, it
is passed through another distilling apparatus, preferably like that illustrated in
Figure 4 except that it is advisable that the catch-all drums 69 and 70, con-
denser 114 and receiving tanks 116 of the second still should be made of copper
lined with tin so as not to contaminate the glycerin of the second distillation.
After this second distillation, the glycerin is introduced into the concentrator 156,
through the pipe 167 and is heated so as to drive off the water therein by
steam in the steam coil 160. The watery vapor passing out of the still 156
enters the catch-all 143, by means of the pipe 175 and is condensed and
collected in the receiving drum 147. This concentration is carried on until the

page_text: distillate has reached a specific gravity of 1·262 for dynamite purposes, or even
higher if necessary.
It is obvious that by making use of a catch-all 143 and in providing means for
returning the glycerin caught therein back to the concentrators, that the loss of
glycerin during the operation of concentration is reduced to a minimum.
Although it is not necessary to subject the crude glycerin to a second distillation
and concentration, yet such course is desirable, because it is impossible to completely
prevent small quantities of glycerin from being entrained or carried over by the
distillate of the first concentration, which distillate will often contain one-one
hundredth of one per cent. of chloride. It is also apt to be contaminated by a
recognisable quantity of an organic impurity of a resinous nature, which, as it has
a lower boiling point than the glycerin, comes off with the first portion of the
distillate and may thus be separated from the first or from the second distillate.
In place of separating this resinous impurity by fractional distillation, it may be
removed by washing the sweet waters of the first distillation with lime and in
filtering it through bone black, prepared black or any other suitable filtering
materials.
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. In the art of recovering products from spent soap lyc, the improvement which
consists in removing the suspended heavy impurities as a sediment, allowing the
lye to cool, whereby suspended soap is brought to the surface and dissolved soap is
separated and suspended and as such is brought to the surface and then skimming
off separated soap from the surface, the operation being carried on previous to the
addition of any chemical to the lye.
2. In the art of recovering products from spent soap lye, the improvement which
consists in first allowing the lye to cool, then removing separately the suspended
heavy impurities and part of the soap contained therein and subsequently liming
the lye as and for the purpose described.
3. In the art of recovering products from spent soap lye, the improvement which
consists in separately removing the suspended heavy impurities and part of the
soap contained therein previous to any addition of chemicals and subsequently
adding to the lye sufficient ferric sulfate to almost neutralize the contained alkaline
hydrate and carbonate, as and for the purpose described.
4. In the art of recovering products from spent soap lye, the improvement which
consists in separately removing the suspended heavy impurities and part of the
contained soap, then liming the lye and adding to the lye sufficient ferric sulfate to
almost practically neutralize its contained alkaline hydrate and carbonate as and
for the purpose described.
5. In the art of recovering products from spent soap lye, the improvement which
consists in first separately removing suspended impurities and part of the soap
previous to any addition of the chemicals, then adding ferric sulfate to the lye to
almost neutralize its contained alkaline hydrate and carbonate and then filtering
the lye, as and for the purpose described.
6. In the art of recovering products from spent soap lye, the improvement which
consists in precipitating fatty and other impurities by addition of ferric sulfate in
quantity sufficient to almost neutralize the contained alkaline hydrate and carbonate,
passing the lye through a filter press, and subsequently steaming the filter cake
produced, as and for the purpose described
7. In the art of recovering products from spent soap lye, the improvement which
consists in precipitating fatty and other impurities by addition of ferric sulfate in
quantity sufficient to almost neutralize the contained alkaline hydrate and carbonate,
passing the lye through a heated filter press, and subsequently steaming the filter
cake produced, as and for the purpose described.
8. In the art of recovering products from spent soap lye, the improvement which
В

page_text: consists in precipitating fatty and other impurities by addition of ferric sulfate in
quantity sufficient to almost neutralize the contained alkaline hydrate and carbonate,.
passing the lye through a filter press, removing the filter cake, mixing it with
water, and passing the mixture through a filter press, as and for the purpose
described.
9. In the art of recovering products from spent soap lye, the improvement which
consists in precipitating fatty and other impurities by the addition of ferric
sulfate, without previous addition of acid, filtering the liquid, bringing it up to
the boiling point and filtering it again, as and for the purpose described.
10. In the art of recovering products from spent soap lye, the improveme..t
which consists in precipitating fatty and other impurities by the addition of
ferric sulfate, filtering the liquid, adding a small quantity of an alkali, bringing the
liquid to the boiling point and filtering again, as and for the purpose described.
11. In the art of recovering products from spent soap lye, the improvement
which consists in precipitating fatty and other impurities by the addition of ferric
sulfate without previous addition of acid, filtering the liquid, evaporating the liquid,
and recovering separately a mixture of sodium sulfate and chloride and separating
the sulfate from such mixture, as and for the purpose described.
12. In the art of recovering products from spent soap lye, containing sodium
sulfate, the improvement which consists in recovering separately a mixture of
sodium sulfate and chloride by evaporating the liquid to a density of 30° Beaume
at 15 degrees C. and separating the sulfate and chloride obtained, as and for the
purpose described.
13. In the art of recovering products from spent soap lye containing sodium
sulfate, the improvement which consists in recovering separately a mixture of
sodium sulfate and chloride by evaporating the liquid, then concentrating the
glycerin up to a density of 30° Beaume at 15° C. as and for the purpose
described.
14. In the art of recovering products from spent soap lye, the improvement
which consists in first purifying the lye by a suitable precipitating agent, then
evaporating the lye until it reaches a density of about 30° Beaume at 15° C.
and separating the salt obtained during such evaporation, then continuing the
evaporation until the liquid is sufficiently concentrated and recovering separately
the salt obtained in the latter operation, as and for the purpose described.
15. In the art of recovering products from spent soap lye, the improvement
which consists in first precipitating the impurities from the lye, filtering the lye,
precipitating crystalline salts by concentration, removing the adherent liquid
material from such crystalline salts and subjecting the salts to the action of a
steam spray to cause further removal of the adhering liquid, as and for the purpose
described.
16. In the art of recovering products from spent soap lye, the improvement
which consists in first precipitating impurities from the lye, filtering the lye,
precipitating crystalline salts by concentration, removing the adherent liquid
material from such crystalline salts and subjecting the salts to the action of a
steam spray in vacuo to cause further removal of the adhering liquid, as and for
the purpose described.
17. As an improvement in vacuum evaporators, the combination of an evaporator
body, an eduction pipe therefrom, connected with a chamber, and a perpendicular
pipe in said chamber, communicating by means of its upper open end located
in the upper part of said chamber with a vacuum pump, substantially as
described.
18. As an improvement in vacuum evaporators, the combination of an evaporator
body, an annular dash plate in the upper part thereof, and a circular dash plate
located beneath the annular dash plate, substantially as described.
19. As an improvement in vacuum evaporators, the combination of an evaporator
body, an annular dash plate in the upper part thereof, a circular dash plate located
beneath the annular dash plate, an eduction pipe from said evaporator body

page_text: connected with a chamber and a perpendicular pipe in said chamber, communicating
by means of its upper open end located in the upper part of said chamber, with a
vacuum pump, substantially as described.
20. As an improvement in vacuum evaporators, the combination of an evaporator
body, an eduction pipe therefrom connected with a chamber, a perpendicular pipe
in said chamber communicating by means of its upper open end located in the
upper part of said chamber, with a second chamber, and a vacuum pump connected
with said second chamber, substantially as described.
21. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, an eduction pipe
therefrom connected with a pump, and a perpendicular pipe in said chamber com-
municating by means of its upper open end located in the upper part of said
chamber with a vacuum pump, substantially as described.
22. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, draw-off pipes below
said drum and located at a distance from the bottom of the evaporator, an eduction
pipe from said evaporator connected with a chamber, and a perpendicular pipe in
said chamber communicating by means of its upper open end located in the upper
part of said chamber, with a vacuum pump, substantially as described.
23. As an improvement in vacuum evaporators, the combination of the
evaporator body, an annular dash plate in the upper part of the evaporator, a
circular dash plate located beneath the annular dash plate, and a tubular steam
heating drum in the lower part of the evaporator, substantially as described.
24. As an improvement in vacuum evaporators, the combination of the
evaporator, an annular dash plate in the upper part of the evaporator, a circular
dash plate beneath the annular dash plate, a tubular steam heating drum in the
lower part of the evaporator and draw off pipes below said drum and located at a
distance from the bottom of the evaporator, substantially as described.
25. As an improvement in vacuum evaporators, the combination of an evaporator
body, an annular dash plate in the upper part of the evaporator, a circular dash
plate located beneath the annular dash plate, a tubular steam heating drum in the
lower part of the evaporator, an eduction pipe therefrom connected with a
chamber, and a perpendicular pipe in said chamber communicating by means of
its upper open end located in the upper part of said chamber, substantially as
described.
26. As an improvement in vacuum evaporators, the combination of an evaporator
body, an annular dash plate in the upper part thereof, a circular dash plate located
beneath the annular dash plate, a tubular steam heating drum in the lower part of
the evaporator, draw-off pipes beneath said drum and located at a distance from the
lower part of the evaporator, an eduction pipe in said evaporator connected with a
chamber, and a perpendicular pipe in said chamber communicating by means of its
upper open end located in the upper part of said chamber, with a vacuum pump,
substantially as described.
27. In an evaporating apparatus, the combination of the evaporators 1 and 2, and
a catch-all 57, common to both evaporators, substantially as described.
28. In an evaporating apparatus, the combination of the evaporators 1 and 2, a
catch-all 57, common to both evaporators, and a vacuum pump connected with said
catch-all, substantially as described.
29. In an evaporating apparatus, the combination of the evaporators 1 and 2, a
catch-all common to both evaporators, a receiving vessel 60 connected with said
catch-all and a vacuum pump connected with said receiving tank, substantially as
described.
30. In an evaporating apparatus, the combination of the evaporators 1 and 2, a
catch-all 57, common to both evaporators, a perpendicular pipe 58 in said catch-all
communicating by means of its upper open end located in the upper part of said
catch-all, with a receiving vessel 60, and a vacuum pump connected with said
receiving vessel, substantially as described.

page_text: 31. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, and two or more
draw-off pipes 15, arranged vertically one above the other for the purpose
mentioned, substantially as described.
32. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, a door in the
evaporator beneath said steam beating drum,' aud one or more draw-off pipes
beneath said steam heating drum arranged vertically one above the other for the
purpose mentioned, substantially as described.
33. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, one or more draw-off
pipes beneath said steam heating drum and a vacuum draw-off pipe 19 beneath said
steam heating drum for the purpose mentioned, substantially as described.
34. As an improvement in vacuum evaporators, the combination of an evaporator
body, a tubular steam heating drum in the lower part thereof, a door in the lower
part of said evaporator beneath said steam heating drum for the purpose mentioned,
one or more draw-off pipes 15 beneath said steam heating drum, a vacuum draw off
pipe 19 beneath said steam heating drum, and a door 14 above said steam heating
drum, substantially as described.
35. In an evaporating apparatus, the combination of the evaporators 1 and 2, the
pipe 33, from the evaporator 1 and the pipe 35 from the evaporator 2, connected
with the pipe 33 at the top of the same for the purpose mentioned, substantially as
described.
36. In an evaporating apparatus, the combination of the pillars 3, the braces 4 at
the top of said pillars, the evaporators 1 and 2, supported by said braces, and a
catch-all 57 common to both evaporators substantially as described.
37. In an evaporating apparatus, the combination of the still, the heater and
expansion coil in the heater, a coil in the still and a steam pipe connected with the
coil in the still, the expansion coil of the heater and the space in the heater
surrounding the expansion coil, substantially as described.
38. In an evaporating apparatus, the combination of the still, a heater and
expansion coil in the heater, a coil in the still, a steam pipe connected with the coil
of the still, the expansion coil of the heater and the space in the heater surrounding
the expansion coil and a perforated delivery pipe in the still connected with the
expansion coil, substantially as described.
39. The combination of a still and eduction pipe connected with the first of
a series of communicating drums and a perpendicular pipe connected with the last
of said drums and with a condenser, substantially as described.
40. In an evaporating apparatus, the combination of a still and eduction pipe
connected with the first of a series of communicating drums, pipes communicating
between said drums and the still, and a perpendicular pipe connected with the last
of such drums and with a condenser, substantially as described.
41. In an evaporating apparatus, the combination of a still, a catch-all drum or
drums connected therewith, a condenser 114 connected with said catch-all drum or
drums, a receiving tank 116 connected with said condenser and a vacuum pump
connected with said receiving tank, substantially as described.
42. In an evaporating apparatus, the combination of a still, a heater and
expansion coil in the heater, a coil in the still, a steam pipe connected with the coil
of the still, the expansion coil of the heater and the space surrounding the expansion
coil, a perforated pipe in the still connected with the expansion coil, an eduction
pipe connected with the first of a series of communicating drums, a perpendicular
pipe connected with the last of said drums, and with a condeuser and a vacuum
pump connected with said condenser, substantially as described.
43. In an evaporating apparatus, the combination of a still, catch-all drums 69
and 70 connected together and with said still, a pipe 101 from each of said catch-all
drums, a pipe 103 connecting said pipes 101 and communicating with the still,
a pipe 105 connected with the pipe 103, a condenser 114, connected with the catch-

page_text: all drum 70, a receiving tank 116 connected with the condenser 114, and a vacuum:
pump connected with said receiving tank, substantially as described.
44. In an evaporating apparatus, the combination of the standards 68, the-
braces 71 at the tops of said standards, the heater 66, still 67 and catch all.
drums 69 and 70 supported by said braces, the condenser 114 connected with the
catch-all drum 70, the receiving tank 116 connected with the condenser 114 and.
vacuum pump connected with said receiving tank, substantially as described.
45. As an improvement in vacuum concentrating apparatus, the combination of a.
concentrator and eduction pipe leading into a chamber, a perpendicular pipe in said
chamber open at its upper end and a pipe connecting said chamber with the
concentrator, substantially as described.
46. As an improvement in vacuum concentrating apparatus, the combination of
two concentrators communicating with a common catch-all and a pipe establishing a
communication between said catch-all and one of said concentrators, substantially
as described.
47. As an improvement in vacuum concentrating apparatus, the combination of a.
dash plate in the upper part of a still, an opening therein, of a circular imperforate
dash plate located below or above and opposite the opening in the large dash plate,.
substantially as described.
48. As an improvement in vacuum evaporators, the combination of an evaporator
body, the annular dash plate in the upper part thereof, a circular dash plate located
above or beneath the annular dash plate, an eduction pipe from said evaporator
body connected with a chamber, and a perpendicular pipe in said chamber with its
upper open end located above the level of the eduction pipe, and communicating
with a vacuum pump, substantially as described.
49. An improved dash plate for use in vacuum evaporators or similar chambers,
in which liquids or fusible solids are heated, comprising the annular dash plate
within the chamber and an imperforate dash plate supported above or below the
annular dash plate, and in line with the opening, therein, substantially as.
described.
Dated this 26th day of June 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants..