DE1028874B - Method and device for breaking up straw - Google Patents

Description

GERMAN

For the digestion of cellulosic materials such as ζ. B. rye, wheat and barley straw and others annual plants, the well-known free-standing or ball cookers have been used for a long time, in which the to be digested Cellulose-containing material is heated under pressure with alkaline or acidic liquids will. In order to completely moisten the cellulose-containing starting material with lye and the approach well to mix, the lye is drawn off at the bottom of the cooker and at the top of the cooker Cooker returned while the ball cooker is allowed to rotate slowly. These two measures will be hereinafter referred to as mixture of substances.

It has now been found that existing free-standing and spherical stoves can be used to a greater extent for the digestion of straw if the digestion is carried out in stationary or stationary spherical boilers with an alkali ratio of 1:10 to 1:20, preferably 1:10 to 1 : 15, at normal pressure and temperatures between 90 and 100 ^° C. with stirring of the straw mass.

The drawing shows a device such as that used for carrying out the method according to the invention will. A spherical cooker 1 of conventional design is stored at 2 and 3. His drive device 4 is locked so that the stove can no longer turn. The vertical shaft 6 of the stirring device protrudes through the manhole 5 into the stove. In the embodiment of the device shown in the drawing the stirring device consists of the two propellers 7 and 8 located on a shaft, the upper one Propeller 7 is mounted above the center of the cooker, but so that he is in the normal cooker filling lies within the substance. The blades of the two propellers 7 and 8 can be rotated in opposite directions will. The power requirement of the drive device for the agitator is a multiple of the power requirement the previously used drive device for ball cookers, preferably about 4 to 8 times. At Any other agitator device can be used instead of the agitator consisting of two propellers. The substance can be drained through a lower valve connector 9 attached to the spherical cooker.

To carry out the process of the invention fills the digester with hot liquor, the temperature of 90 to 100 ⁰ C, preferably 90 to 95 ⁰ C, is. It is filled so far that the upper stirrer is covered by the lye and that the lye forms a cone or funnel when the stirrer is started up. If you now pour chaff into the digester, the chaff is sucked in by the intake cone formed by the lye and very quickly brought under the surface of the liquid. So much chaff is filled in that the stock dilution, by which the ratio of chaff to lye is understood here, is in the range from 1:10 to 1:20, preferred method and device
for breaking up straw

Applicant:

Paper and cardboard stock company,
Düsseldorf-Holthausen, Henkelstr. 67

Dipl.-Ing. Franz Offermanns, Inden (Kr.Jülich),

Adolf Rühling, Düsseldorf,

and Albin Körner, Monheim (Rhld.) - Blee,

have been named as inventors

wise from 1:10 to 1:15. The temperature of the kettle contents is maintained by the addition of steam at 90 to 100 ⁰ C, preferably 90 to 95 ° C.

By arranging a propeller above the middle of the digester height is achieved) that with a minimum The force required for the agitator is the strong rotation required to form a feed cone the fluid is maintained. It is not necessary that the one located in the lower part of the cooker Fluid participates in this strong rotation. As soon as the chaff has been entered into the lye, you can even stop stirring completely. Since, however, the digestion of the cellulose-containing materials is evened out by stirring you can ensure that the material in the lower part of the stove is also swirled through will. In the device shown in the drawing, this is done by a two-propeller agitator, wherein the upper propeller pushes the liquid downwards and thus the formation of a cone in the liquid promotes. If the blades of the lower propeller are turned in the opposite direction to the upper propeller, lifts the liquid is applied to it, and an upper and a lower flow circuit is formed. When the filling the chopping is finished, the agitation can be reduced. For example, you have the filling of the chop at a peripheral speed of the agitator of about 9 to 12 m / sec. made so the peripheral speed after filling can be increased to about 4 to 8 m / sec. be lowered.

The method according to the invention makes it possible to reduce the time required for breaking up the straw, which takes about 3 to 5 hours in normal kettle operation, to about ¹ _1/2 to 1 hour. Oei; increased stock throughput equates to the stronger stock thinning

805 5 & 7/223 ¹

the ball cooker at a speed of 2 revs / min. After the end of the boiling, the water content of the cooking material was due to the condensation water that formed increased to about 12000 kg. The material was processed in the refiner and then finely sorted subject.

b) New way of working

For this purpose, a spherical cooker of the same size as under a) was used, the one with a stirrer, as in the drawing was shown, provided.

Add to kettle 155 kg of caustic soda was charged as 0.57 ° / ₀ aqueous solution of 9O ⁰ C. Then it became

not only increases the performance compared to the old digester processes - twice as much more. In addition, the strength properties of the cardboard or papers obtained from these materials are improved.

If several stoves are available, this can be done
Process according to the invention designed continuously
be e.g. B. by being in a first cooker with strong
rotating agitator above the center of the
Kochers is appropriate, the mixing of chaff and io
Lye made and the unlocking started
will. The fabric is then peeled off the bottom and from there
into a second and, if necessary, transferred from this in an analogous manner to further digesters, the agitators of which do not need to form feed cones and the agitator is set in motion. It ran at 120 rpm. run at slower speeds. At this rate it formed in the liquid

Since the invention essentially relates to the appara- a strong intake cone, in which 2600 kg tive design as quickly as possible, details of the normal rye straw chop were filled. The chemical part has not been described. Self-made straw immediately disappeared under the surface of the liquid, and the invention can of course be carried out with all the usual topping-up solutions. 1 hour WOR mixture was heated with direct steam at 95 ⁰ C and indeed there are already described Strohkochungen maintained at this temperature. After the lye was used in a much larger amount for 1 hour, the digestion was complete. The cooker was emptied up to about 15.3 times the amount of straw, and the material obtained was processed in the refiner, but in both cases it is a matter of laboratory tests and it has not been neglected to turn off For the substances obtained according to a) and b), it was pointed out that a cardboard box was produced here from the conditions of a test cardboard machine, something that has been removed from practice. In one case, the following table compares the test results with the amount of lye used in practice. When specifying 2.4 times the amount of straw per hour, and in another 3 ° processed amount of chaff, it must be taken into account that the discussion of the results obtained with 8 times the amount of lye, the numerical values refer to the pure cooking time, are no longer obtained considered necessary because working with such amounts of caustic was not considered acceptable. This is understandable
because working with such high amounts of caustic leads to a 35
Means reduction of throughput. According to the invention 3
the technical difficulties caused by this can only be overcome by working under violent
Stirring works. Because of this, the invention
also only in the combination of a large amount of caustic 40 χ
and vigorous stirring in free-standing or stationary spherical boilers.

It is also already known cellulosic materials open with stirring. In one case it acts

If one were to take the filling times into account, these numerical values would be even further in favor of the postpone the new procedure.

Chopped / hour processed yield,% / ₀

Cardboard speed of the
Machine, m / min

. ,,,., ",,. ,, ο ..!, j . _c Cardboard weight, g / m ²

thereby but is wood, not straw, and 45 p _a pnenstärke lie with straw so far very different conditions prevail '

when the finely chopped straw, in contrast to wood, is difficult to submerge in the lye. With others Similar proposals concern apparatuses specially elaborated for stirring, from which not even the problem on which the invention is based can be recognized, which consists in existing systems to make it more exploitable. In addition, in no case does the need for large dilution of the substance be considered pointed out to be able to manage the stirring at all.

mm

H ₂ O content,

Burst pressure at 10 cm ² burst area, kg / cm ²

Burst pressure at 100 cm ² burst area, kg / cm ²

Burst strength

Tear length, m

Elongation, ° / ₀

Old process

1.25 73

279 0.43 8.75

3.6

1.02 3.64 3527 2.95

New procedure

2.6 73

266 0.38 9.47

5.25

1.33 5.04 4523 3.45

example

In the example, the old way of working is compared with the new way of working.

a) Old way of working

5000 kg of chopped rye straw were poured into a spherical cooker of normal design and 33.5 m ^{3 with the aid of a tamper.} At the same time, 350 kg of caustic soda were added as a 3.7% aqueous solution. The cooker was then heated to 5 atmospheres with direct steam. The cooking time was 4 hours, the total rotation 7 hours. During the cooking ran

Claims (3)

Claims 1. Process for digesting straw with increased utilization of existing facilities, thereby characterized in that the digestion at an alkali ratio of 1:10 to 1:20, preferably 1:10 to 1:15, at normal pressure and temperatures between 90 and 100 ° C while stirring the straw mass in Standoder dormant spherical boilers. 2. Apparatus for performing the method according to claim 1, consisting of a stand or dormant ball cooker of known type, which is provided with a stirrer, its vertical stationary drive shaft through a manhole of the Kugelkochers or the closure of this manhole is performed, the power requirement of the drive device for the agitator a multiple of that for the drive device of the material mixing in the old construction. 3. Apparatus according to claim 2, characterized in that the stirring device is above the center of the ball cooker is arranged. Considered publications: German Patent Nos. 553 966, 562 770; French Patent Nos. 703 039, 869 331; British Patent No. 628 171; Der Papierfabrikant, year 1941, p. 269; Writings of the Association of Cellulose and Paper Chemists and Engineers, Volume 24: Cellulose 1939-1946 by Georg Jayme, Darmstadt, 1953, pp. 37, 38. 1 sheet of drawings © «09 507/223 4.58