WO2019043001A1

WO2019043001A1 - Method for conveying and dosing small damp leather pieces into a reactor

Info

Publication number: WO2019043001A1
Application number: PCT/EP2018/073129
Authority: WO
Inventors: Dietrich Tegtmeyer; Jens BERNSHAUSEN; Christoph Fleischer; Dietmar Guenther; Dierck WIEMANN
Original assignee: Lanxess Deutschland Gmbh
Priority date: 2017-08-29
Filing date: 2018-08-28
Publication date: 2019-03-07
Also published as: AR113103A1; MX2020001984A; CN111032886A; EP3676407A1; KR20200044002A; BR112020003562A2

Abstract

The invention relates to a method for conveying and dosing small damp leather pieces into a reactor, to the use of a tube chain conveyor for conveying such leather pieces, to a device for treating small damp leather pieces, comprising a reactor and a conveyor means for the leather pieces in the form of a tube chain conveyor, and to a method for treating small damp leather pieces for producing retanning materials.

Description

Process for conveying and metering small pieces of moist pieces of leather into a reactor

In the production of leather fall in the adjustment of the thickness, the so-called folding, large amounts of wood shavings, so-called Lederfalzspäne, which consist mainly of collagen-containing material. In Germany alone, this is about 7,000 t, worldwide about 600,000 t per year. Therefore, there is a constant search for new possibilities for recycling this material. The shavings fall while wet (about 50% residual moisture) as flakes (comparable planing or sawdust) or herbaceous strands. However, a promotion turns out to be difficult, since the damp Falzspäne tend under pressure to irreversible compaction. Since wet leather is known to have a rather high frictional resistance, compaction has already been established or expected in most known automated conveyor systems, so that open conveyor belts have become standard in tanneries.

However, open conveyor belts have significant drawbacks such as increased contamination, poor dosability, and the inability to overcome large differences in altitude over a short distance.

EP 2714756 discloses an advantageous process by means of which retanning agents can be produced from leather shavings or other small pieces of leather in a reactor. This makes it possible to produce from the waste in leather production, which are incurred by far the greater part in the tannery, new raw materials for tanning, which can be used directly on site, thus in addition to reducing the waste and the same expenses to optimize the transport. However, the installation and operation of a plant for such a process requires extensive technical know-how, which is often not available to a required extent in a tannery.

One solution to this problem would be to provide such equipment in modular form, for example in containers, advantageously in dimensions not exceeding the size of a 53ft (16.15m x 2.59m x 2.90m container, preferably a 40ft isocontainer ( 12.19m x 2.43m x 2.69m), with the essential , ,

Plant parts for the method i. at least one reactor and a conveyor for small pieces of moist pieces of leather are integrated into the container. By means of the conveyor system, the wet leather particles, in particular Lederfalzspäne be promoted by a feed device to the higher inlet opening of the reactor and subjected to hydrolysis in the reactor and, where appropriate, further chemical reactions.

In order to enable such a plant, there was a need for a new process for conveying small pieces of moist leather pieces, preferably leather shavings, which avoids the disadvantages of the prior art. If possible, a closed conveyor system should be used to avoid contamination during production. In addition, the transfer between the conveyor system and the reactor would also be advantageous as a closed system. Furthermore, larger conveyor heights should be achieved per horizontal distance than with conveyor belts to allow feeding the pieces of leather from the top of the reactor within the confined conditions of a container. In addition, the Lederfalzspäne should not or only slightly compressed during transport, otherwise there is a threat of blockage of the transport system. In addition, a uniform delivery rate was desirable in order to achieve good metering. Furthermore, a precise detection of the amount of dosed leather pieces would be desirable.

A tube chain conveyor is known to the person skilled in the art and is used for conveying bulk materials. It typically comprises at least one respective tensioning station, a drive station, a tubular housing, a revolving conveyor chain with drive disks mounted at specific intervals. The conveyor chain is guided through the tube housing and forms limited spaces through the driver disks in the tube housing, so-called tube chain segments, which move in the tube as a result of the movement of the circulating chain and thus enable transport of the conveyed material. Tube chain conveyors are u.a. sold by the company Hartmann, Wardenburg and the company Schräge, Friedeburg.

Due to the large surface on the inside in conjunction with the high friction resistance of wet leather pieces, as well as their tendency for bridging and compaction, it was expected that a strong compression of the leather pieces takes place in the tube chain conveyor, which leads to a blockage of the conveyor system and thus is not suitable for the transport of such leather particles.

Surprisingly, it has now been found that small pieces of moist leather pieces, preferably leather shavings can be conveyed in a tube chain conveyor, without the , ,

To compress leather pieces appreciably and thereby trigger a blockage of the conveyor system.

This made it possible to provide methods according to the invention which avoid the disadvantages of the prior art.

An essential aspect is therefore a method for conveying small pieces of moist leather pieces, preferably leather shavings comprising the promotion of the leather pieces in a tube chain conveyor.

By finely divided are typically meant dimensions of the leather (LxWxH) of up to 200x30x4 mm, preferably of up to 150x20x3mm and more preferably of up to 120x20x3 mm, with leather-shavings also larger dimensions are included, since the leather-falzspäne when folding occasionally in the form of strands or herbaceous forms.

Moist leather particles are typically understood to mean those having a water content of at least 35% by weight, preferably at least 45% by weight and particularly preferably at least 50% by weight. The upper limit of the water content is arbitrary, preferably 90 wt.%, Particularly preferably 80 wt .-%.

Suitable devices for this process, which are also objects of the present invention, are as follows: The broadest embodiment relates to a device for treating small-sized pieces of moist leather, preferably leather shavings, in a reactor comprising a reactor and a tube chain conveyor as conveying means for the pieces of leather.

The term treatment preferably means the chemical treatment of pieces of leather, more preferably their hydrolysis, ie the chemical reduction of the molecular weight of the collagen chains of the leather, with further reactions being able to follow. With very particular preference, treatment means the chemical transformation of the leather pieces into retanning agents, as described in EP 2714756. With retanning agents are meant auxiliaries, which are incorporated in the re-tanning in the leather matrix. Synthetic tanning agents, vegetable tanning agents and resin and polymer tanning agents can be used for this purpose, in particular also syntheses, substitution tanning agents. Particularly preferred retanning agents are graft polymers of acrylic acid and / or methacrylic acid with hydrolyzed amylose and / or , ,

hydrolyzed proteins, as also described in EP 2714756. Preferably, the hydrolyzed amylose are present in the form of short-chain saccharides and the hydrolyzed proteins in the form of short-chain peptides, as described in each case in EP 2714756.

As a reactor, in principle, any suitable for the respective chemical treatment reaction container is suitable, which can then be suitably selected by the skilled person according to the respective requirement profile. In the device according to the invention, the pieces of leather are typically conveyed through the tube chain conveyor to the reactor. With a corresponding emptying device can thus be achieved a closed feeding system for the leather pieces. Preferably, the filled with the pieces of leather tube chain segments of the tube chain conveyor are emptied from above into the reactor. In a particularly preferred embodiment, the emptying is supported by brushing. The brushes are preferably moved relative to the tube chain segments, for example, oscillating or rotating movements of the brushes are useful. Suitable brush cleaning stations are u.a. in DE19728053. If a precise dosage is desired, the filling of the tube chain conveyor with the pieces of leather can be done by a screw. The degree of filling of the chain segments can be suitably adjusted by adjusting the delivery rate of the screw and tube chain, so that the pieces of leather can be transported without compressing them.

A further improvement in the precision of the metering can be achieved by placing the reactor on weighing elements and thus more accurately monitoring the supply of material, in particular to the pieces of leather in the reactor. A spiked shaft positioned in front of the screw can further reduce bridging and lumping of the pieces of leather in the feeding device, especially in the case of difficult substrates. Preferably, such a shaft is arranged above the worm, so that the leather pieces are conveyed by gravity to the worm.

In a further embodiment, the worm can be equipped on the circumference with cutting edges, which cuts longer strands of leather pieces so that it facilitates the filling of the tube chain segments. , ,

In the system according to the invention, the pieces of leather can be fed batchwise (for example via transport containers by forklift) or continuously into the feed device and can be fed from there into the reactor at a controllable metering rate. A supply of the leather pieces to the feeding station via a conveyor belt is alternatively possible.

Suitable task devices are u.a. sold by the company Hartmann, Wardenburg for oilseeds or by the company Schräge, Friedeburg. By using one or more tube chain conveyors, a vertical lifting of the pieces of leather of at least 1 m, preferably at least 1.5 m and particularly preferably at least 2 m can be achieved even in a compact system, the vertical increase over a horizontal distance of less than 10 m, preferably less than 4 m, and more preferably less than 2 m can be accomplished.

Thus, it is possible to incorporate the device according to the invention as a module in a container with the maximum extension of a 40 foot isocontainer. This allows easy transport of such a system on the road, the rail or on the water and thus, for example, a temporary equipment a tannery with such a device.

Another aspect of the invention is a process for the treatment of small pieces of moist leather pieces, preferably leather shavings, comprising the promotion of the leather pieces by means of a tube chain conveyor and the chemical treatment of the leather pieces in a device according to the invention.

The invention also relates to a process for the preparation of retanning agents from small pieces of moist pieces of leather, preferably leather shavings, comprising the promotion of the leather pieces by means of a tube chain conveyor and the hydrolysis of the leather pieces in a device according to the invention. Optionally, for example, amylase hydrolyzate can be added. Preferably, a further polymerization step is then carried out with acrylic acid or methacrylic acid. A further aspect of the invention is a process for the production of leather (tanning), wherein the resulting in the production of small-sized moist pieces of leather, preferably leather shavings, converted by a device according to the invention in retanning and the retanning agents are returned to the process for the production of leather , - -

Example:

An example of a plant for carrying out the process according to the invention is shown in FIG. This includes the following components:

1 . Feeding device, arranged next to the production plant, with storage container

2. integrated spike shaft to avoid bridging

3. screw conveyor for discharging the pieces of leather in the tube chain conveyor, speed adjustable to adjust the flow rate

4. circulating transport system (tube chain conveyor) with

Tube chain for transporting the leather pieces to the hydrolysis reactor in the pilot plant

variable-speed drive system for the realization of different dosing rates

5. Special brush system for complete emptying of the discharge from the chain segments into the reactor (possibly via a downpipe)

6. reactor for receiving and processing the leather pieces with

Weight and / or volume measurement

- Suction

Stirrers and

optionally means for promoting hydrolysis, e.g. B. Dispersing machine

7. Process control technology / automation with

Procedures for processing procedural recipes

including the metering specifications for the Falzspanzufuhr (e.g., dosing rate and

Total quantity)

Processing of weight and volume information of the reactor

Control of the drives of the transport system (tube chain conveyor) Control of the drive of a dispersing machine

Control of the drive of a stirring device

Processing of information and derivation of actions for safe operation of conveying and dosing of pieces of leather.

Claims

claims

A method for conveying small pieces of moist leather pieces, preferably leather shavings comprising the promotion of the leather pieces in a tube chain conveyor (4).

A method according to claim 1, wherein the tube chain conveyor (4) conveys the pieces of leather to a reactor (6).

Process according to claim 1 or 2, wherein an emptying of the tube chain segments into the reactor (6) takes place by means of brushes (5).

Method according to one or more of claims 1 to 3, wherein a dosage of the leather pieces in the tube chain conveyor (4) by a screw (3).

Method according to one or more of claims 1 to 4, wherein the tube chain conveyor (4) causes a vertical lifting of the leather pieces of at least 1 m, preferably at least 1, 5 m and more preferably at least 2 m.

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

Method according to one or more of claims 1 to 6, wherein the conveyed amount of leather parts is measured by balance elements on which the reactor (6) stands.

Method according to one or more of claims 1 to 7, wherein this is carried out in a plant comprising a container with the maximum extent of a 53 foot transport container, preferably a 40 foot isocontainer, wherein at least the tube chain conveyor (4) and the reactor (6 ) are integrated in the container.

A process for the treatment of small-sized pieces of moist leather comprising a process according to one or more of claims 1 to 8, and a subsequent chemical treatment of the small pieces of moist pieces of leather in the reactor (6).

A method of treating small-particle wet pieces of leather according to claim 9, wherein the chemical treatment comprises hydrolysis.

1 1. The method of treating small-particle wet pieces of leather according to claim 10, wherein the chemical treatment comprises a polymerization reaction subsequent to the hydrolysis.

12. A process for the treatment of small-sized moist leather pieces according to one or more of claims 9 to 1 1, preferably claim 1 1, wherein from the small-particle moist leather parts retanning agents are produced.

13. A process for the production of leather, wherein the obtained in the production of small-sized moist pieces of leather, preferably the leather shavings, converted by a method according to claim 14 in retanning and the retanning agents are recycled to the process for the production of leather.

14. A process for the preparation of retanning agents from small pieces of moist leather pieces, preferably leather shavings, comprising the promotion and subsequent hydrolysis of the leather pieces according to one or more of claims 10 to 12.

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