DE3041508C1 - Process for the production of sugar beet pulp with a high dry matter content - Google Patents

Description

The invention relates to a process for the production of sugar beet pulp with a high dry matter content, beet pulp by mixing with dehydrating substances and mechanical pressing freed from liquid to form pressed chips in at least one stage and, if necessary, then to be dried.

In a known method of this type (DE-PS 31 285) is also residual extraction juice, the consists mainly of water, removed from the beet pulp. As dehydrating substances are preferably molasses or (column 4, lines 31 to 34) calcium chloride, aluminum sulfate, aluminum phosphate and silica used, some of which go into solution with the press water and from it in the Juice cleaning must be removed again. The so diluted molasses is z. B. by a multi-stage evaporator thickened and returned to the process. The aforementioned substances can be the press carving Withdraw water to a limited extent only. The undissolved remainder of the dehydrating substances often remains ι undesirable way in the last resulting Endpreßschnitzeln. The handling is cumbersome and requires a lot of equipment and energy. A recycling of the dehydrating substances is economically not possible.

ίο The invention is based on the object Dry matter content of the pressed pulp during mechanical pressing with simple means, energy-saving and to increase inexpensively, to shorten the pressing time and to remove the dehydrating substances from the Keep final pressed pulp away.

This object is achieved according to the invention in that porous bodies are used as the dehydrating substance are used, each after the pressing including the pressing liquid taken up by them be removed from the pressed pulp. In contrast to the well-known "chemical" removal of press fluid is here a "physical" one. Upon contact with water-containing Sugar beet pulp and the at least approximately anhydrous porous bodies become the concentration gradient of the water balanced under pressure, d. i.e., there is water from the chips into the porous ones Body over. This increases the dry matter of the schnitzel in a simple and very effective way.

The porous bodies are preferably inert to the chips, of high mechanical strength and abrasion-resistant and have good sliding properties on the surface. It is also advantageous if the porous bodies are resistant to weak acids (pH 5 to 6) and biodegradation. from It is also advantageous if the porous body, including the pressing fluid they absorb be removed from the respective pressed chips before before the subsequent pressing with These pressed chips are mixed with other porous bodies capable of absorbing pressing fluid. Through this is an undesirable withdrawal of pressing fluid from the loaded porous bodies by the new ones receptive porous bodies excluded.

If the porous bodies are added to the wet beet pulp from sugar production before the first pressing, an increase in the drainage effect can be achieved. In some cases, a second mechanical pressing is no longer necessary because the pressed chips produced after the first pressing already have a sufficiently high dry matter content.
Mixing the porous bodies with the pressed pulp only for the second pressing and, if necessary, for each subsequent pressing creates the possibility of initially pressing a large part of the liquid out of the beet pulp in the conventional manner as coarse drainage before the fine drainage during repeated pressing porous bodies are used.

With claim 2 one obtains porous bodies with a particularly large capacity for the pressing fluid. In addition, it has been observed that open-pore bodies in the under pressure Chip heaps (press cake) promote drainage. It is believed that the

ORIGINAL! MSPECTED

Open pores defined channels in the bodies form favored flow paths.

The dimensional stability of the porous body according to claim 3 is particularly effective in the aim of to form the press cake non-compressible cavities and disturbance channels. In these cavities is to flow released during the pressing process pressing fluid and ultimately accumulate what through the Porosity of the porous body is still favored (suction effect). This effect should especially also in the Run off inside the press cake, as this area is opposite to the outside of the screen jacket or inside of the perforated spindle located areas of the press cake is disadvantaged in the drainage effect.

The porous bodies according to claim 4 are is optimal with regard to the size of the surface offered per volume unit and can, for. B. a Have a diameter of 30 to 50 mm.

When the porous body is formed according to claim 5, the capillary suction effect that the porous body is 2f> exerts on the press liquid surrounding it, particularly large. The materials according to claims 6 to 8 are well suited for the intended application. In the case of claim 8, the porous body z. B. off Polyvinyl chloride, polypropylene or polyethylene are made. Natural substances according to claim 9 are also possible, z. B. pumice stone or coke.

The measure of claim 10 leads to a simple and complete classification of pressed pulp and porous bodies enriched with pressing fluid, without the significant proportions of the absorbed pressing fluid could escape prematurely from the porous bodies.

According to claim 11, it is then possible to very quickly and completely out of the J5 expel porous bodies before the again liquid-free porous body in the sense of a Recycling can be used again.

As a very effective and inexpensive way of removing pressing fluid from the porous Centrifugation has proven to be beneficial for bodies.

The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing explained.

The drawing shows a flow diagram of two alternative processes.

The first process sequence is drawn with full lines. In doing so, a transport element 1 Wet beet pulp in a first pulp press 2 to carry out a first mechanical pressing process entered. From the first cossette press 2 press liquid emerges through a line 3 and The first pressed pulp reach a second pulp press 5 via a transport element 4.

Already in the transport element 4 or in an unspecified, known inlet of the second cossette press 5 are mixed with the first press cuttings porous body through a Transport element 6 are brought up. In the second pulp press 5, a mixture is made first pressed chips and porous bodies pressed. In the process, pressing liquid is obtained from the second pulp press 5 discharged through a line 7 and a mixture of second pressed chips and press liquid arrives enriched porous bodies via a transport element 8 in a vibrating sieve device 9, in which this mixture is classified in such a way that the second pressed pulp by a transport element 10 and the porous body enriched with press fluid by a transport element 11 are discharged from the vibratory screening device 9.

The transport element 11 promotes the press liquid enriched porous body in a preferably continuously operating centrifuge 12, in which the Pressing liquid is ejected as quickly and completely as possible from the porous bodies and the Centrifuge 12 leaves through a line 13. The processed porous, freed from the pressing fluid in this way Bodies pass from the centrifuge 12 into the transport element 6 and into the process cycle return.

Screw presses are preferably used as the pulp presses 2, 5. The press liquid is largely water.

For example, the wet beet pulp has 8-9% by weight DS (dry matter), the first pressed pulp 22-28% by weight DM and the second pressed pulp 30-40% by weight DM. That’s already a Reached dry matter content that was previously either not at all or only with an unacceptably high total effort is attainable.

Another important advantage of the method according to the invention is the considerable shortening the pressing time, because the temporary storage of the porous body in the pressed chips within the Press cake in the respective pulp press of the press fluid flow paths into the porous body that would otherwise not exist. Without such a porous body It is known that capillaries are used when pressing in the area of the outer drainage surface of the sugar beet pulp squeezed and thereby the removal of pressing liquid from the chips made more difficult. This is especially true for those areas of the press cake which are in relation to the enclosing walls of the pulp press are far away. The porous bodies ultimately enlarge the pressing fluid absorbing Surface within the pulp press quite considerably, so that more pressing liquid in less time Schnitzel can be withdrawn.

The dry matter content of the second pressed pulp in the transport element 10 is not yet sufficient off, the second pressed cuttings can in turn admixed and porous bodies free of pressing fluid this mixture can be entered into a third pulp press, not shown. In most In some cases, however, a third and possibly further pressing stage will prove to be unnecessary. Much more In most cases, the second pressed pulp can either undergo thermal post-drying subjected or immediately used in particular as fodder.

In the drawing, a second alternative process sequence is shown partially with dashed lines. The beet wet chips are already either in the transport element 1 or in one Inlet of the first pulp press 2 receptive porous bodies via a transport element 6 branched transport element 6 'admixed. A mixture of the first pressed pulp and the with Pressing liquid-enriched porous bodies passes through a transport element 4 'from the first pulp press 2 and is separated in a vibrating screening device 14 into the first pressed pulp, which has a Transport element 15 into transport element 4

get, and in the enriched with pressing fluid porous body, which via a transport element 16 in the Centrifuge 12 are introduced. Otherwise, the second process sequence is the same as that described above, and the first process sequence shown in solid lines in the drawing.

1 sheet of drawings

Claims (11)

Patent claims: 1. Process for the production of sugar beet pulp high dry matter content, wherein Beet pulp by mixing with dehydrating substances and mechanical pressing Pressed chips freed of liquid in at least one stage and, if necessary, then are dried, characterized in that the dehydrating substance is porous Bodies are used, each after the squeeze including those ingested by them Pressing liquid can be removed from the pressed chips. 2. The method according to claim 1, characterized in that the porous bodies are open-pored. 3. The method according to claim 1 or 2, characterized in that the porous body below Compression pressure are at least approximately dimensionally stable. 4. The method according to any one of claims 1 to 3, characterized in that the porous body have at least approximately spherical shape. 5. The method according to any one of claims 1 to 4, characterized in that the porous body have a pore size of about 1 mm. 6. The method according to any one of claims 1 to 5, characterized in that the porous body consist of rigid plastic foam. 7. The method according to claim 6, characterized in that the porous body made of rigid polyurethane foam exist. 8. The method according to any one of claims 1 to 5, characterized in that the porous body consist of a foamed thermoplastic. 9. The method according to any one of claims 1 to 5, characterized in that the porous body consist of minerals. 10. The method according to any one of claims 1 to 9, characterized in that the porous body including the pressing liquid taken up by them from the respective pressed chips Vibration screening can be removed. 11. The method according to any one of claims 1 to 10, characterized in that the porous bodies are those made up of those in a preceding one Pressing absorbed press liquid was expelled as completely as possible.