CN111032886A

CN111032886A - Method for feeding small, moist leather sheets into a reactor and metering them

Info

Publication number: CN111032886A
Application number: CN201880056687.7A
Authority: CN
Inventors: 迪特里克·特格特迈尔; 延斯·伯恩斯豪森; 克里斯托夫·弗莱舍尔; 迪特马尔·京特; 迪克·维曼
Original assignee: Lanxess Deutschland GmbH
Current assignee: Lanxess Deutschland GmbH
Priority date: 2017-08-29
Filing date: 2018-08-28
Publication date: 2020-04-17
Also published as: WO2019043001A1; EP3676407A1; KR20200044002A; AR113103A1; BR112020003562A2; MX2020001984A

Abstract

The invention relates to a method for feeding small, moist leather pieces into a reactor and metering them; to the use of a pipe chain conveyor for conveying such a leather sheet; relates to a device for processing small, moist leather sheets, comprising a reactor and a conveying device for the leather sheets in the form of a tube chain conveyor; and to a method for treating small moist pieces of leather in order to produce a post-tanned material.

Description

Method for feeding small, moist leather sheets into a reactor and metering them

In leather production, when the thickness (also called shaving) is set, a large amount of leather shavings, so-called leather shaving chips, are produced, which consist mainly of collagen-containing material. In germany alone, this amounts to 7,000 tons, whereas around 600,000 tons are available worldwide each year. There is therefore a constant search for new recycling possibilities for the materials.

The shaved chips (approximately 50% residual moisture) in the moist state herein appeared as flakes (equivalent to wood shavings or sawdust) or strands of herbs. However, transport proves difficult because moist shavings tend to compact under pressure in an irreversible manner. Because wet leather is known to have a rather high frictional resistance, compaction has been observed or has to be expected with most known automatic conveyor systems, so that open conveyor belts have been established as a standard in tanneries.

However, open conveyors are associated with significant disadvantages, such as high contamination, poor metering capability, and inadequate height differential over short distances.

An advantageous process is disclosed in EP 2714756 by which post-tanning material can be produced in a reactor from leather shaving scraps or other small leather pieces. It is therefore advantageous to produce a new starting material for tanning that can be used directly on site and that, therefore, in addition to reducing the waste, at the same time optimizes the complexity in terms of transport, produced from the waste generated in the leather production, which so far has in fact been the most prevalent in tanneries.

However, the establishment and operation of the equipment for such a process requires a great deal of technical knowledge, which is not usually possible to the necessary extent in tanneries.

One solution to this problem is to provide such a device in a modular form, for example in the form of a vessel, advantageously of a size not exceeding the size of a 53ft vessel (16.15m × 2.59m × 2.90m), preferably a 40ft ISO vessel (12.19m × 2.43m × 2.69m), wherein important parts of the equipment for the process (that is to say at least one reactor and conveying equipment for small moist leather pieces) are integrated in the vessel. Moist leather particles, in particular leather shaving crumbs, are transported from the headbox device by means of a transport device to the inlet opening of the reactor at a higher level and are hydrolyzed and optionally subjected to further chemical reactions in the reactor.

In order to realize such a device, a new method for conveying small moist pieces of leather, preferably shavings of leather, is required, which avoids the disadvantages of the prior art. Ideally, a closed delivery device should be used in order to avoid any contamination during delivery. Furthermore, it is also advantageous to design the transition between the conveyor system and the reactor as a closed system. In addition, a greater conveying height per horizontal section should be possible than in the case of a conveyor belt, in order to be able to feed the leather pieces into the reactor from above under the closed conditions of the vessel. Furthermore, the leather shaving debris should not be compressed or only slightly compressed during transport, since the transport system additionally risks becoming blocked. Furthermore, uniform delivery rates should also be targeted in order to achieve a positive metering capability. In addition, it is desirable to accurately detect metered quantities of leather pieces.

Pipe chain conveyors are known to those skilled in the art and are used for conveying bulk goods. The pipe chain conveyors usually comprise in each case at least one tensioning station, a drive station, a tubular housing, a rotating conveyor chain with a driving disk attached at specific intervals. The conveyor chain is guided through the tubular housing and, as a result of the driving disks, defined chambers, so-called tube segments, are constructed in the tubular housing, which tube segments are displaced in the tubes by the movement of the rotating chain and thus enable the transported goods to be transported. Tube chain conveyors are sold primarily by Hartmann, Inc. of Wurden and Schrage, Inc. of Friedberg.

Due to the large surface on the inside combined with the high frictional resistance of the wet leather sheet and the tendency of the leather sheet to bridge and compact, it is expected that strong compression of the leather sheet in the pipe chain conveyor may occur, which leads to a blockage of the conveyor system and is therefore not suitable for transporting such leather particles.

It has now been surprisingly found that small moist leather pieces, preferably shavings of leather, can be conveyed in a pipe chain conveyor without significantly compressing the small leather pieces and thus causing blockage of the conveyor system.

This is achieved by providing a method according to the invention which avoids the disadvantages of the prior art.

An important aspect is therefore a method for conveying small moist leather pieces, preferably shavings of leather, which comprises conveying the leather pieces in a tube chain conveyor.

Small pieces generally mean dimensions of the leather (l x w x h) of up to 200 x 30 x 4mm, preferably up to 150 x 20 x 3mm, particularly preferably up to 120 x 20 x 3mm, wherein larger dimensions are also included in the case of leather shaving crumbs, since leather shaving crumbs occasionally also occur in the form of strands or herb-like shapes when shaving.

Moist leather particles are generally understood to be leather particles which have a water content of at least 35% by weight, preferably at least 45% by weight, particularly preferably at least 50% by weight. The upper limit of the water content is arbitrary in this context, preferably 90% by weight, particularly preferably 80% by weight.

A suitable apparatus for this process, which is also the subject of the invention, is designed as follows:

the most comprehensive embodiment relates to an apparatus for treating small moist leather pieces, preferably shavings of leather, in a reactor, comprising a reactor and a pipe chain conveyor as conveying means for the leather pieces.

The term "treatment" preferably refers to a chemical treatment of the leather piece, particularly preferably a hydrolysis of the leather piece, that is to say a chemical reduction of the molecular weight of the collagen chains of the leather, possibly followed by further chemical reactions. As described in EP 2714756, treating most particularly preferably means chemically converting the leather sheet into a post-tanned material.

Post-tanned material in this context means an auxiliary material which is embedded in the leather matrix at the time of post-tanning. Synthetic tanning materials, vegetable tanning materials and also resinous and polymeric tanning materials, in particular also synthetic organic substitute tanning materials, can be used for this purpose. Particularly preferred post-tanning materials are graft polymers of acrylic acid and/or methacrylic acid with hydrolysed amylose and/or hydrolysed protein, as also described in EP 2714756. The hydrolyzed amylose herein is preferably present as short-chain sugars and the hydrolyzed protein is preferably present as short-chain peptides, as in each case described in EP 2714756.

Any reaction vessel envisaged for the respective chemical treatment is in principle suitable as a reactor, which can then be appropriately selected by the person skilled in the art according to the respective requirement profile.

The leather sheet in the apparatus according to the invention is typically conveyed to the reactor by a pipe chain conveyor. Thus, a closed feed system of leather sheets can be achieved using a corresponding emptying device. The tube strand of the tube chain conveyor filled with leather sheets is preferably emptied into the reactor from above. In a particularly preferred embodiment, the emptying is supported by a brush. The brush here is preferably moved relative to the tube strand, wherein, for example, an oscillating or rotating movement of the brush is advantageous. A suitable brush cleaning station is disclosed in DE 19728053.

Filling the tube chain conveyor with leather pieces can also be done by a screw if precise metering is desired. The filling level of the chain segments in this context can be suitably adjusted by adjusting the conveying rate of the screw and the tube chain, so that the leather pieces can be transported without these leather pieces being compressed.

A further improvement in the metering accuracy can be achieved, since the reactor is placed on a balance element and the feeding of material, in particular leather pieces, into the reactor can thus be monitored more accurately.

The pin roller shaft, which is positioned in front of the screw, can further minimize the formation of bridges and lumps of leather pieces in the headbox installation, especially in difficult basement situations. Such a shaft is preferably arranged above the screw so that the leather sheet is conveyed to the screw by gravity.

In a further embodiment, the screw may be circumferentially equipped with blades that cut relatively long strands of leather sheet so that they help to fill the tube segments.

In the apparatus according to the invention, the leather sheet can be supplied to the headbox installation batchwise (for example by forklift-handled transport containers) or continuously and fed from there into the reactor at a metering rate which can be closed-loop controlled. It is alternatively possible to feed the leather sheet into the headbox installation by means of a conveyor belt.

Suitable headbox devices are sold, in particular, by Hartmann, Inc. of Wurden Castle (for rapeseed) or Schrage, Inc. of Fredberg.

Due to the use of one or more pipe chain conveyors, a vertical lifting of the leather sheet of at least 1m, preferably at least 1.5m, particularly preferably at least 2m, can also be achieved in a compact plant, wherein the vertical lifting can be done over a horizontal distance of less than 10m, preferably less than 4m, particularly preferably less than 2 m.

Thus, the device according to the invention can be installed as a module in the largest range of vessels with 40ft ISO vessels. This enables such equipment to be transported simply by road, rail or water, and thus also enables tanneries, for example, to equip such devices temporarily.

A further aspect of the invention is a method for treating small moist leather pieces, preferably shavings of leather, comprising conveying the leather pieces by a pipe chain conveyor and chemically treating the leather pieces in an apparatus according to the invention.

The invention also relates to a method for producing post-tanning material from small moist leather pieces, preferably from shavings of leather, comprising conveying the small leather pieces by means of a pipe chain conveyor and hydrolyzing the leather pieces in the device according to the invention. For example, an amylase hydrolysate may also optionally be added. Preferably, a polymerization step using acrylic acid or methacrylic acid is also carried out subsequently.

A further aspect of the invention is a process for the production of leather (tanning), wherein small moist pieces of leather, preferably leather shavings, present in the production are converted into post-tanned material by the apparatus according to the invention, and the post-tanned material is returned to the process for the production of leather.

Example (c):

an example of a device for carrying out the method according to the invention is shown in fig. 1. The apparatus comprises the following components:

1. a headbox installation, which is arranged beside the production plant and has a storage vessel;

2. an integrated needle roller for avoiding bridge formation;

3. a conveyor screw for conveying the leather sheet into the pipe chain conveyor, capable of closed-loop control in terms of rotational speed in order to adapt the conveying rate;

4. circulating transport system (pipe chain conveyor) with

-a pipe chain for transporting the leather pieces to the hydrolysis reactor of the test plant;

a drive system which can be closed-loop controlled in terms of rotational speed in order to achieve different metering rates;

5. a dedicated brush system for emptying the transferred volume completely from the chain segment into the reactor (optionally through a down pipe);

6. a reactor for receiving and treating leather pieces, the reactor having

-a weight or volume measuring unit;

-a suction unit;

-stirring means; and

-optionally means for supporting hydrolysis, such as a dispersing device;

7. process management technology/automation, having

-a program for executing a formula according to a process technology;

metering parameters (e.g. metering rate and total amount) including the feed for shaving the crumb;

-processing reactor information on weight and volume;

open/closed loop control of the drive of the transport system (pipe chain conveyor);

-open/closed loop control of the drive of the disperser;

-open/closed loop control of the drive of the stirring device;

-processing of information and derivative actions of reliable operation

-conveying and metering of leather pieces.

Claims

1. A method for conveying small moist leather pieces, preferably shavings of leather, comprises conveying the leather pieces in a pipe-chain conveyor (4).

2. The method of claim 1, wherein the pipe chain conveyor (4) conveys the leather pieces to a reactor (6).

3. The method according to claim 1 or 2, wherein emptying the tube strand into the reactor (6) is performed by the support of a brush (5).

4. The method as claimed in one or more of claims 1 to 3, wherein the metering of the leather pieces into the pipe chain conveyor (4) is carried out by means of a screw (3).

5. The method as claimed in one or more of claims 1 to 4, wherein the pipe chain conveyor (4) lifts the leather pieces vertically by at least 1m, preferably by at least 1.5m, particularly preferably by at least 2 m.

6. Method according to one or more of claims 1 to 5, wherein vertical lifting takes place over a horizontal distance of less than 10m, preferably less than 4m, particularly preferably less than 2 m.

7. Method according to one or more of claims 1 to 6, wherein the amount of leather pieces conveyed is measured by means of a balance element on which the reactor (6) rests.

8. The method of one or more of claims 1 to 7, wherein the method is carried out in an apparatus comprising a container of maximum extent with 53ft shipping containers, preferably 40ft ISO containers, wherein at least the pipe chain conveyor (4) and the reactor (6) are integrated in the container.

9. A method for treating small moist leather sheets, comprising the method according to one or more of claims 1 to 8, and the subsequent chemical treatment of these small moist leather sheets in a reactor (6).

10. The method for treating small moist leather pieces according to claim 9, wherein the chemical treatment comprises hydrolysis.

11. The method for treating small moist leather pieces according to claim 10, wherein the chemical treatment comprises a polymerization reaction after the hydrolysis.

12. Method for treating small moist leather sheets according to one or more of claims 9 to 11, preferably according to claim 11, wherein a post-tanning material is generated from the small moist leather portions.

13. A process for the production of leather, wherein small moist pieces of leather, preferably leather shaving scraps produced in production, are converted into post-tanning material by the process as claimed in claim 14, and these post-tanning material are returned to the process for the production of leather.

14. A method for post-production tanned materials from small moist leather pieces, preferably leather shaving crumbs, comprising conveying the leather pieces and subsequently hydrolyzing them as claimed in one or more of claims 10 to 12.

15. Use of a pipe chain conveyor for conveying small moist pieces of leather, preferably shavings of leather.