Process and Apparatus for the Production of Invert Sugar and Dextrose.
Year: 1892

page_text: Date of Application, 5th Sept., 1892-Accepted, 8th Oct., 1892
Process and Apparatus for the Production of Invert Sugar and
Dextrose.
1, Dr. ALWIN RUMPLER of Tschauchelwitz near Rothsürben (Prussia) in the
Empire of Germany, 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 present invention relates to the inversion of sugar solutions, and the saccha-
rification of starch, by means of volatile or gascous acids, casily soluble in water,
and especially sulphurous acid.
According to processes in use up to the present time, the acids, when the inversion
or saccharification is complete, are separated by the addition of lime, or neutralized
with soda, so that considerable quantities of salts always remain behind in the sugar
solutions, which detract from the purity of the product.
This disadvantage is avoided by the process forming the subject of the present
invention, according to which, the acid required for the inversion or saccharification
of a certain amount of solution, is recovered, and rendered fit for the inversion or
saccharification of a further quantity of solution.
This process consists in the recovery from the solution, by distillation, of the
used acid, next, introducing it into a new lot of solution, and then, after having
performed the inversion or saccharification upon this second lot, again driving off
the acid by distillation, and leading it into another quantity of solution.
For carrying out the process, the apparatus shewn in the accompanying drawing
is employed.
This consists of two copper vessels a and b, Fig. 1, made capable of withstanding
a pressure of 12 to 15 atmospheres, and similar to those employed for the production
of dextrose from potato starch.
These vessels are connected by pipes to a cooling apparatus c, so as to form a
compound or duplex apparatus.
In these, pipes are placed cut-off valves. By the combination of these two
boiling vessels with the cooling apparatus, the advantage is gained of being able
(by means of the cooling apparatus) to distil over into the one boiling vessel, the
volatile acid used for the inversion of sugar solutions, or the saccharification of
starch in the other vessel, that is, to free the one vessel from the volatile agent,
and to use it over again in the other. In this manner, the volatile agent is
continually and alternately employed first in one vessel and then in the other.
The action of the duplex apparatus is as follows:-
If cane or beet sugar is to be converted into an invert sugar solution, the cañe or
beet sugar is mixed in a pulverised form with water in an agitating vessel situated
above the duplex apparatus. To prevent a vaporization of the solution finally
obtained, the proportions of the mixture of sugar and water should be as 100 to 25.
The invert sugar solution so obtained is of the consistency of honey, and is fit
for use without further manipulation. Thinner or weaker sugar solutions must be
condensed as far as necessary.
After the production of the solution, the varions cocks and valves of one of the
vessels, say a, are closed, with the exception of an air cock in the dome at the
top, and steam is admitted by the cock e (which, instead of being situate in the side
of the vessel, as shewn, is better placed in the bottom thereof), till it issues forcibly
from the air cock d, to effect as complete an exclusion of the air contained in the
vessel as can be obtained. On closing the cock e of the steam pipe, the pressure in
the vessel will fall, by reason of the escape of the steam from the air cock, as
indicated by the manometer, to any desired point, when the air cock d will be closed
in any convenient manner, and the valveg opened to admit the sugar solution from
D

page_text: the mixing vessel above. The portions of the sugar syrup first entering will
condense what little steam is left in the vessel a, and thereby cause the formation of
a vacuum, when the rest of the syrup will be rapidly drawn in.
When the vessel has been filled with the desired quantity of sugar and water, the
valve (Fig. 1) is opened, and, through the connection i in communication
therewith, "100 per-cent." sulphurous acid from an iron bottle is introduced, till
the syrup has taken up the desired quantity, which is ascertained by a sample drawn
from a tap in the vessel.
The best solution is found to consist of 100 parts water and 5 parts of sulphurous
acid free from water, but the quantity of the latter can be increased or diminished,
if the period of boiling be curtailed or lengthened. If it is desired to avoid the
necessity of ascertaining the degree of saturation of the liquid remaining in the
apparatus, the sulphurous acid can be weighed in, that is, by taking the weight of
the iron bottle before and after introducing the gas. After the introduction of the
acid is concluded (ie., when the valve has been closed), the next thing is to boil
the mixture contained in the vessel. For this purpose, the bottom of the apparatus
is furnished with a steam coil k, to which steam is admitted by the valve 1, and fills
not only the coil, but the space m between the double bottom, thus effectively
heating the mass.
The steam escapes through a tube surrounding that used for the admission of
the acid, as shewn in Fig. 2 in horizontal section. The mass is heated by steam
for about 30 minutes to a temperature of 100º. While this is proceeding, the
other vessel has been got ready in the same manner for the boiling operation, by
opening the cock e', filling the vessel with steam, & then, when the steam has,
for the most part, escaped through the air cock d', letting in the sugar syrup
through the valve g¹. If, now, the inversion in vessel a has been completed, the
pressure of the steam is lowered by means of the valve l, and the valves o and pl
opened, these making the connection between both the vessels and the condensing
coil of the cooler c. Simultaneously, the water is turned on surrounding the
worm q.
The sulphurous acid now escapes out of the vessel a, is cooled by passing through
the worm g, and enters, by the pipe, the middle pipe i of the double pipe
body shewn at Fig. 2, passing thence into the mass in the vessel (the upper
part of which is in vacuo), to be absorbed therein.
After all the acid gas has escaped from a, which can be easily tested by taking a
sample therefrom, the valves o and p' are closed, and a new process is begun with
respect to vessel b, the valve l' being opened, and steam admitted to the coil and
into the double bottom of this vessel.
In the meantime, the vessel a is emptied through the exit valves on the tube i,
the air is driven out by filling with steam, and the vessel is then filled with a
fresh mass, by means of the condensation of the steam, so that this vessel is ready
to take the place of in the boiling process, the sulphurous acid gas being again
withdrawn from b into a, and so on.
The mass drawn from the apparatus is placed in a filter press furnished with
cotton cloths, and is either allowed to pass through by its own weight, or is drawn
through by a pump, to be placed in suitable vessels for transport.
The boilers are provided with thermometers tt, manometers u u³, liquid
gauges v vl, sight holes, w w¹, and manholes & x'.
The saccharification of starch, and the like, is effected in the same manner as the
inversion of cane sugar, only the mixture of starch and water is made thinner
(1 and 1 is a good proportion), and boiled longer (about 3 hours), and at a higher
temperature (about 120° C.) than with the inversion of sugar.
Instead of sulphurous acid, other strong, and either gaseous or volatile acids
can be employed, provided that they are soluble in water to a sufficient extent.
For the inversion of sugar, formic acid is particularly suitable, its high cost being
not of much moment, from the fact of its being able to be used over and over again
in this process, if only sugar is employed which does not yield too much ash.

page_text: The peculiarity of this apparatus is not so much in the construction of the
separate operating vessels (as these are commonly employed in all branches of
chemistry, under the names of boiling pans, autoclaves, digesters etc.), but in the
combination of two or more of such vessels (autoclaves) with a
cooler or
condensing arrangement 7, and the valves o p¹, o' p, to each apparatus, thus
enabling the already used gas, or gaseous acid, to be transferred from one
apparatus to the other for reuse.
The condenser is particularly necessary to effect this, as were it not for this, on
opening the valves o p (for example) the gases would only pass out of a into b, until
the pressure in both become equal, and then stop. By condensing the gases,
however, the whole of the acid gas can be got out.
In the practical working of this system, the sulphurous acid, when driven off, is
trapped into water, or lime and water, to prevent contamination of the surrounding
atmosphere. If any acid be lost by leakage, it must be replaced by fresh acid to
a like extent.
Finally, it is to be remarked, that instead of two, a series of 3, 4, or more
apparatus may be combined together and used in turn, one after another.
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:
1. A process for the recovery of the volatile or gaseous acid (soluble in water)
used for the inversion of sugar and the saccharification of starch, etc., and using
it for the same purpose over again, and consisting in recovering the said acid
by distillation, out of the solution, and introducing it into a fresh quantity of
solution, after the complete inversion of the first lot, again expelling it by
distillation, and using it again, and so forth.
2. For the carrying out of the process referred to in Claim 1, an apparatus
consisting of 2 or more vessels or "autoclaves " a and b, connected together by
means of condensing tubes q, and furnished with valves, in such manner, that the
acid driven from one vessel through the pipes q, is transferred to the other vessel
for further use as set forth.
Dated this 5th day of September 1892.
NEWTON & SON,
Agents for the Applicant.