Year: 1886

page_text: Date of Application, 6th Dec., 1886
Complete Left, 5th Sept., 1887
Complete Accepted, 6th Jan., 1888
I, CHARLES KELLNER, Manufacturing Chemist of Podgora, near Görz, Austria, do
hereby declare the nature of this invention to be as follows:
The substances forming the incrustations of wood, straw, esparto or other ligneous
materials, are decomposed by chlorine, or by certain compounds of the same with
oxygen, such as hypochlorous acid, thereby causing the extraction of hydrogen and
the formation of hydrochloric acid.
The chlorine necessary for decomposing the incrustations or its oxygen compounds
is obtained by the electrolysis of suitable chloride solutions contained in closed vessels,
together with the wood or other vegetable matter to be treated, and by the simultaneous
application of heat to the contents of the vessels. I have obtained excellent results
by using sodic chloride as an electrolyte, the products of the electrolysis being in
this case chlorine or hypochlorous acid on one hand and sodic hydrate on the other
hand, because the liberated ions, namely chlorine and sodium, act on the water and
form thereby the compounds mentioned above.
The hydrochloric acid formed by the decomposition of the incrustations as well as
by the heating of the hypochlorous acid, acts on the sodic bydrate, and forms again
sodic chloride with the same, so that a complete cycle of operations is established and
the same liquid operates in undiminished strength during the whole process; which
constitutes an essential advantage of my process.
I have found that the process works sinoothly at 128° Centigrade and that a snow
white, silk like, fibre is obtained from wood, without loss of strength.
Besides sodic chloride I have tried to use as electrolytes a long series of other com-
pounds, such as dilute hydrochloric acid, and magnesic chloride, and have obtained
good results.
For carrying out my process I use preferably an apparatus in which the liquid
circulates continuously when heated. For instance I may employ a tubular apparatus
having three vertical tubes situated in one plane and connected with one another at
the top and at the bottom. The two electrodes enter at the bottom of the lateral
tubes, and in the upper part of that lateral tube in which the electro-negative ions

page_text: chlorine, hypochlorous acid) ascend during the heating, is interposed the receptacle
containing the fibrous vegetable matter.
The liquids containing the ions or their products of reaction which ascend in the
lateral tubes, are united at the top, after which the liquid descends again through
the central tube. When this liquid passes the electrodes the chlorides are again
decomposed.
Very good results are obtained with this apparatus by changing the current, in
which case the second ono of the lateral pipes is also filled with wood or other fibrous
vegetable matter. With this modification, the vegetable matter is alternately sub-
jected to the influence of alkaline and acid agents. The soda lyo formed by the
process decomposes or prepares the incrustations in such a manner that the latter are
very easily and rapidly dissolved on the changing of the current.
It is evident that the apparatus for carrying out my process may be modified in
various ways; for instance I may employ an apparatus in which the cooking receptacle,
(that which is filled with wood), revolves.
Dated this 6th day of December 1886
FAIRFAX & WETTER,
433, Strand, London, W.C.,
Agents for the Applicant.

page_text: I, CHARLES KELLNER, Manufacturing Chemist, of Podgora, near Görz, Austria, 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 Process for obtaining cellulose or ligneous fibre for textile industries and for
the manufacture of paper from suitable vegetable matter, such as wood, grass and
vegetable stalks, chiefly consists in boiling the said vegetable matter with solutions of
compounds which are decomposed by an electric current into bodies adapted to dissolve
the incrustations (namely the foreign substances or impurities which accompany the
wood fibre), and at the same time conducting an electric current through the said
solutions. By this operation the bodies entering into solution are subjected to the
electrolytic action of the current, and useful bye products are formed.
According to the nature of the electrolyte and the condition of the vegetable matter
to be treated (wood, straw, &c.) I boil or heat the vegetable matter in vessels which
resist a high steam pressure and which allow the liquids to circulate as required. In
some cases impart a rotary motion to the vessel containing the vegetable matter.
For electrolytes which attack iron or which yield corrosive substances by electrolysis,
the boiler or heating vessel must consist of or be lined with incorrodible material.
The application of my new principle may be described as follows:
The foreign admixtures or incrustations of wood, straw, esparto or other ligneous
matter are decomposed by chlorine or by certain oxygen compounds of the same, for
instance hypochlorous acid. The chlorine or its oxygen compound applicable for my
process is produced by the electrolysis of suitable chloride-solutions, preferably
solutions of sodic chloride, which are contained in closed vessels, together with the
vegetable matter, and the contents of the vessels are at the same time heated.
The products of this operation are chlorine or hypochlorous acid on the one hand,
and sodic hydrate on the other hand, because the liberated ions, namely chlorine and
sodium, act on the water, thereby producing the compound mentioned above.
The hydrochloric acid, formed by the decomposition of the incrustations and by the
heating of the hypochlorous acid, acts on the sodic hydrate, so as to produce again
sodie chloride. In this manner a complete cycle is established, and the same liquid
may act repeatedly with undiminished energy. I have found that at 128° centigrade,
the process works smoothly, and yields a snow-white, silky fibre of undiminished
strength.
Besides sodic chloride, and instead of it, I have employed as electrolyte a long
series of other compounds, such as diluted hydrochloric acid and magnesic chloride,
and have obtained good results.
The following example will clearly show the details of procedure.
For obtaining from the wood of coniferous trees white cellulose or wood fibre suit-
able for the manufacture of paper, the wood is first cut into small pieces by well-
known machinery, and then placed into the digestors, the latter being then closed and

page_text: a solution of common salt admitted to the same.
As a rule, a 5 per cent solution and
a temperature of 126° C. maintained for about 3 hours are sufficient for producing
from fir wood a solid white material suitable for the manufacture of fine paper.
The inside of the boilers or digestors must, of course, be rendered proof against
the products of decomposition, by lining them with lead, acid-proof glazing or enamel,
or with acid-proof cement or putty, or by other known means.
The construction of the apparatus may differ in many respects, consequently, I do
not limit myself to any particular form. The accompanying drawing illustrates an
apparatus which has given good results and which is constructed as follows:-
It chiefly comprises two digestors A and A' connected at the bottom with pipes r, 1
and at the top with pipes s, & M and M" are openings for charging the digestors
and M and openings for emptying the same, each being provided with a cover,
b, b,,, are perforated plates which prevent fibres or particles of plants from
being carried by the liquid current into the pipes so as to clog the latter.
The digestors A and A' communicate through the pipes s and s¹ with a vessel B,
hereafter called the expansion boiler. This vessel is fitted with a liquid gauge, safety
valve, and blow-off valve. It also carries a pipe connection n which may be closed
by a valve v. The continuation of this pipe n forms the cooling coil n' situatel in the
cooling tank S and communicating with the absorption-vat K through the pipe n
(which is a continuation of n). The lower end of the pipe n" forms a perforated coil
at the bottom of the vessel K. A pipe n joined to the cover of the vessel K leads
gases, which have not been absorbed in the vessel K, into one or more additional
absorption-vats similar to K.
the
The conical bottom of the expansion-boiler B is connected with a pipe C extending
down below the bottom of the digestors, and terminating into the two branchi-pipes r
and mentioned above. The latter lead up to the bottom of the digestors A, A¹ and
contain two carbon-electrodes e and e' which are insulated from the walls of the said
pipes and w¹ are heating coils in the interior of A and A¹.
After A and A have been filled with wood, and sufficient salt-solution has been
admitted to become visible on the liquid gauge of the expansion vessel B, the valve a
is closed, the valves and are opened, and dry steam is admitted through the
pipes & and d into the heating coils and w. As the contents of the vessels A and A¹
are heated, the liquid will rise in the direction of the arrows and pass through the
pipes s, sinto the vessel B, thereby producing a downward current from B through
the cold pipe (circulating pipe) C. At the bottom of pipe C the liquid flows into the
branch pipes and and after having passed through the same in the direction of
the arrows it enters again the digestors A and A' thus making a complete circuit and
remaining in circulation during the entire boiling process. As the liquid passes the
electrodes e, e while the electric circuit through the latter is closed, it is decomposed
and the secondary processes described above are established. If the positive current
enters at e and the negative current at e¹ the incrustations of the wood contained in A
are strongly subjected to oxidation, owing to the action of the chlorine or of its
derivatives, while the resins and similar admixtures of the wood contained in A' are
saponified by the soda ascending in A'. The products of decomposition (as far as
they are soluble) mect in the expansion vessel B and react on each other in such a
manner, as to form again sodium chloride, because the hydrochloric acid produced by
the influence of the anion decomposes the organic soda compounds entering from the
cathode-side, thus reconstructing the original solution of sodium chloride, and
precipitating the organic matter. The continually renewed influence of the chlorine
and its compounds decomposes the organic matter thus separated, into products which
either remain in solution or escape as gases.
After the process has continued as described for about a quarter or half an hour,
the electric current is reversed, so that the terminal which hitherto was the cathode
now acts as anode and vicé-versû.
This alternation of currents is very beneficial because the alternate action of chlorine
and of soda on the wood greatly accelerates the separation of the wood fibre from
its admixtures.

page_text: The current is therefore frequently reversed, about once every half hour, until the
cellulose or wood fibre has been completely laid bare, which occurs after about 3
or 3 hours, if the temperature of the boiling liquid, measured in the digestor, is
about 126° C.
The speed of the circulating liquids should not fall below a certain minimum; con-
sequently the sectional area of A and A' and their height must be kept within certain
limits, or the automatic circulation described above must be assisted artificially, for
instance by a centrifugal pump inserted into the pipe C at p, or by means of a water-
jacket adapted to cool the pipe C.
The gases generated during the process, which take no part in the decomposition
and accumulate in the expansion-vessel B are discharged into the cooling and con-
densing apparatus described above, by periodically opening the valve v inserted
in pipe n.
Each digestor is provided with a thermometer and pressure gauge, in order to
compare the pressure with the corresponding temperatures and to disclose any
abnormal differences which may be caused through the clogging of the sieves by
fibrous particles carried over with the liquid. In this case the valves inserted in s
and s are closed and steam admitted to the top of the sieves b and 6, so as to clear
off any obstructions.
If the process is carried out in the manner described, the digestor under which the
anode is situated at the end of the operation, will contain snowy-white cellulose, suit-
able for the finest kinds of paper without previous bleaching, while the contents of
the digestor situated over the cathode, are slightly coloured yellow by the alkali formed
at the end of the process. The yellow tinge may, however, be removed by treating
the cellulose with a weak chloride of lime solution (one per cent) after the contents of
the digestor have been washed. If the digestion has been continued long the mere
acidulation of the washed product with hydrochloric acid, is sufficient to render it
equivalent to the product of the anion-digestor.
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 as my invention and desire to secure by patent is :—
1. The process for obtaining cellulose or ligneous fibre or for separating the same
from its admixture, which consists in the following simultaneous operations :
a. Boiling or heating fibrous vegetable matter with solutions of compounds,
which, when hot, can be decomposed by an electric current into bodies
adapted to dissolve the incrustations or foreign admixtures of the cellulose.
b. Causing an electric current to pass through the liquid which contains the
vegetable fibrous matter.
2. The process for obtaining cellulose or wood-fibre from ligneous vegetable matter,
which consists in heating the said material with a solution of metallic chloride in a
closed vessel, while the said solution is being decomposed by conducting through it
an electric current.
3. The process for obtaining cellulose or wood-fibre by means of a duplex apparatus
and alternating currents, substantially as described and illustrated.
DL: 1911
T
1
1007
FAIRFAX & WETTER,
433, Strand, London,
Agents for the Applicant.
FAIRFAX & WETTER,
433, Strand, London,
Agents for the Applicant.