CA2285820A1

CA2285820A1 - Pourable methionine-containing shaped bodies and process for the production thereof

Info

Publication number: CA2285820A1
Application number: CA002285820A
Authority: CA
Inventors: Martin Korfer; Gundolf Hornung; Klaus Huthmacher; Hans Joachim Hasselbach; Klaus Bonig
Original assignee: Degussa Huels AG
Current assignee: Evonik Operations GmbH
Priority date: 1998-10-10
Filing date: 1999-10-12
Publication date: 2000-04-10
Also published as: ATE241598T1; JP4588820B2; CN1184897C; EP0992490B2; DE19846825A1; EP0992490A1; ES2200450T3; JP2000116336A; CN1250608A; AU5348199A; ES2200450T5; EP0992490B1; DE59905726D1; MXPA99009235A; BR9904455A; KR20000028898A

Abstract

The invention relates to pourable shaped bodies containing predominantly methionine, and to a process for the production thereof, in which the water is largely removed from an aqueous methionine suspension and the solid so obtained is subjected to a shaping process.

Description

Pourable methionine-containing shaped bodies and process for the production thereof The invention relates to pourable methionine-containing shaped bodies and to a process for the production of those products.
The preparation of methionine or of a salt of methionine, the latter especially as an intermediate stage before isolation of the methionine in a corresponding process, using the starting materials methylmercaptopropionaldehyde and hydrogen cyanide, has long been known and is described in a large number of literature references.
The corresponding methionine salt is produced via the intermediate stage of 5-(~-mercaptoethyl)-hydantoin and subsequent basic hydrolysis using various alkali metal, alkaline earth metal or ammonium compounds. Methionine is freed from the salt with the aid of acids and is isolated by means of a suitable process. The working-up processes for converting the methionine into a condition suitable for further use generally prove to be very expensive.
The methionine produced according to known processes (US-PS

2,557,913, DE-PS 1906405, JP 42/44056) is distinguished by a more or less strongly pronounced crystalline structure.
It is in the form of a white to creamy-white product; the bulk densities are generally from 600 to 700 kg/m3, the particle spectrum range is very widely spread from < 32 ~m to approximately 1200 Vim, the pourability can be greatly impaired especially in the case of a plate structure of the methionine.
From JP-A-59-199670 there is known a process for producing granulated methionine, in which methionine and other granular organic or inorganic materials are mixed as a powder and granulated with the addition of solvents.

The object of the invention is to make available a process which yields shaped, pourable products having a low dust content.
The invention provides pourable methionine shaped bodies, especially extrudates (sic) having a bulk density of from 300 to 850 kg/m3, especially from 600 to 800 kg/m3, and a particle spectrum from 63 ~m to 5000 Vim, especially from 500 ~m to 1500 Vim. They contain methionine in a predominant amount, especially from 60 to 98 wt.%, preferably from 85 to 95 wt.%. Shaped bodies can be produced according to the process known from the prior art.
In a preferred form, the shaped bodies, for example in the form of extrudates or granulates, also contain foreign substances which act as binders.
Those substances are organic or inorganic in nature and are suitable as additives where the products according to the invention are used as feeds.
In an especially suitable embodiment, those compounds come from the methionine preparation process and are optionally contained in the main product as secondary products without having to be separated off beforehand for purification of the main product.
D,L-methionine or a salt of D,L-methionine is generally prepared starting from the components 3-methylmercapto-propionaldehyde, hydrogen cyanide, ammonia and carbon dioxide, or 5-(2-methylmercaptoethyl)-hydantoin.
The synthesis steps can be illustrated by means of the following reaction equations:
formation of 5-(2-methylmercapto)-hydantoin:

O
2H3C-S-CH2-CH2-Crr + 2HCN + 2NH3 + 2C02 .>
O
2H3C-S-CH2-CH2-CH-Crr + 2H20 (1 ) HN NH
~C~
formation of the D,L-methionine salt:
O

2H3C-S-CH2-CH2 ~ H- \ + M2C03 + 3H20 HN~ /NH
C
I I
O
O
O
2H3C-S-CH2-CH2-CH-C + 3C02 + 2NH3 (2) freeing of D,L-methionine:
O
rr 2H3C-S-CH2-CH2-CH-C\ + 2C02 + 2H20 2H3C-S-CH2-CH2-CH-COOH + 2MHC03 (3) M represents an alkali metal, an alkaline earth metal or ammonium, especially potassium.
Processes of that type are described, for example, in DE-PS
1906405.
It is advantageous for the shaping to wash the methionine separated from the preparation process with water or with a mother liquor taken from the preparation process.

It has proved to be especially advantageous if small amounts of dissolved methionine and/or potassium salts, especially potassium carbonate and/or potassium hydrogen carbonate, still adhere to the solid. Those amounts generally range from < 0.1 to 10 wt.%, based on the methionine.
A residual moisture content in the range of from 8 to 40 wt.%, especially from 12 to 25 wt.%, based on the total weight, has proved to be advantageous for the shaping.
In a preferred form, the shaped articles, for example in the form of an extrudate, also contain a binder in an amount of from > 0 to 20 wt.%, based on methionine.
Inorganic compounds such as potassium carbonate and/or potassium hydrogen carbonate are especially suitable as binders.
In order to improve the shaping process, organic binders are also additionally used, individually or together.
Those organic binders include dissolved methionine and other substances, such as methylcellulose, ethylcellulose, carboxymethylcellulose, carboxyethylcellulose, carboxy-propylcellulose, hydroxypropylcellulose, hydroxypropyl-methylcellulose, cellulose acetate dibutylaminoacetate and other cellulose derivatives, starch, hydroxypropyl starch, sugar, dextrin, gelatin, other natural high-molecular-weight substances, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylacetal dibutylaminoacetate, it being possible to use one of those substances on its own or several of those substances together and thus improve the shaping. The binders are preferably used in the form of aqueous solutions.
In order to improve handling of the shaped bodies to be produced, it is recommended to shape the methionine in the presence of silicate-based additives.

Those additives include hydrophilic and hydrophobic silicas of pyrogenic nature, or silicas of from 5 to 300 mz/g prepared by precipitation, preferably spray-dried silicas.
Finely divided zeolites, for example of type A, or 5 bentonites may also be used.
The amount of those and other additives is from 0.1 to wt.%, preferably from 0.1 to 5 wt.%, based on the methionine. Of course, in addition to the silicate-like compounds, those additives preferably include substances 10 that are permitted in the feeds sector, especially fatty acids and their salts, preferably alkali metal or alkaline earth metal salts.
The fatty acids include especially stearic acid and palmitic acid or mixtures of fatty acids containing from 16 to 18 carbon atoms or their above-mentioned salts.
Binders, additives and also feed-effective compounds are added to the suspension of the methionine either in solid form or, optionally, in the form of an aqueous solution, or are added to the separated methionine prior to shaping (e. g. extrusion).
The feed-effective compounds include other amino acids, such as lysine, threonine or alanine or their salts, N-acylamino acids, N-hydroxymethylmethionine calcium salts, 2-hydroxy-4-methylmercaptobutyric acid and other amino acid hydroxy analogues, fish meal, casein, other proteins, vitamin A, vitamin A acetate, vitamin A palmitate, vitamin D3, vitamin E, nicotinic acid, nicotinic acid amide, pantothenic acid calcium, ~-carotene.
Those compounds are used in a total amount of from 0 to 40 wt.%, especially from 1 to 20 wt.%, based on methionine.
The shaped bodies produced according to the invention are then suitable as a complex feed for feeding animals.
The invention also provides a process for the production of methionine-containing shaped bodies, characterised in that the water is removed from an aqueous methionine suspension down to from 8 to 40 wt.%, based on the total amount, and the solid so obtained is shaped, but especially extruded.
In particular, a residual moisture content of from 12 to 25 wt.% has proved to be advantageous for the shaping.
That is the case especially when the methionine is processed following the preparation process and the suspension contains potassium carbonate/hydrogen carbonate and organic secondary products.
The use of a twin screw extruder has proved to be especially suitable for the shaping. The solid is then generally forced through an extrusion die at extrusion pressures of up to 60 bar at temperatures of from 20 to 120°C.
In that manner, extrudates having extrudate diameters of from 500 ~m to 5000 mm (sic), preferably from 800 to 1000 ~,m, are produced.
The length of the extrudate can either be adjusted by mechanical cutting, or the extrudate breaks off as it emerges from the die owing to a suitable selection of the process parameters.
Other suitable apparatuses or processes for the production of shaped bodies which may be mentioned are single screw extruders, ring die presses or pan-grinding apparatuses.
If shaping is carried out at an elevated product temperature, then additional evaporation of water takes place, which markedly facilitates the subsequent drying step.
In some cases it is advantageous to treat the resulting shaped bodies in a so-called "spheronizer" prior to final drying, in order to achieve a rounding of the particles.
The subsequent step, which optionally takes place in vacuo, of drying off from the shaped bodies the residual moisture that is still present must be carried out mechanically in a very gentle manner at least at the beginning in order to prevent the shaped bodies from being damaged or destroyed.

A combination of a drying belt for partially drying the shaped bodies, especially extrudates, and subsequent final drying in a disk dryer has proved successful. The product temperatures are in the range of from 50 to 140°C, prefer-s ably f rom 90 to 110°C .
Especially after that drying process, the shaped bodies have the desired high mechanical strength. That allows the product to be handled simply. The bulk density is then generally from 600 to 800 kg/m3.
The dust content is generally < 1 %, measured by the method of Dr. Groschopp.

Examples Example 1 Methionine having a residual moisture content of 25 wt.%, a KzC03 content of 1.7 % and a KHC03 content of 2.8 % is used.
It is fed to a twin screw extruder at a rate of 10 kg/h.
120 g/h of tylose are added to the intake via a second metering device. The extruder is heated to 110°C and the methionine/tylose mixture is extruded at a pressure of 15 bar through a die having 150 0.8 mm holes. Granulation is carried out by means of a blade rotating directly at the die. The granulate has a moisture content on exit of 23 wt.% and is pre-dried on a drying belt and subjected to final drying on a disk dryer. The particle spectrum is from 400 to 1000 ~,m. The methionine content of the end product is 88 wt.%. The dust content is < 0.5 %, and the particles have high strength.
Example 2 Example 1 is repeated, with the difference that extrusion is carried out using a die having 80 1.2 mm holes at a pressure of 13 bar. The throughput is 12 kg/h. The granulate has a moisture content on exit of 23 %. The particle spectrum is from 600 to 1500 Vim.
Example 3 Methionine having a residual moisture content of 32 wt.%, a KzC03 content of 2.0 wt.% and a KHC03 content of 3.2 wt.% is dried in a contact dryer to a residual moisture content of 16 wt.%. The product is then extruded, without further additives, in a twin screw extruder at a temperature of 30°C and a throughput of 15 kg/h through a die having 0.8 mm holes. After granulation by means of a blade, the particles are subsequently rounded in a spheronizer. Final drying is carried out in a disk dryer. This procedure yields spherical particles having a particle spectrum from 300 to 1000 Vim. The dust content is < 0.5 %.
Example 4 Example 3 is repeated, with the difference that a ring die press is used for the shaping instead of an extruder. The particle spectrum is from 400 to 1200 Vim. The dust content is < 0.5 %.

Claims

1. Pourable methionine-containing shaped bodies, especially extrudates, having a bulk density of from 300 to 850 kg/m3 and a particle spectrum from 63 µm to 5000 µm and having a predominant methionine content, especially from 60 to 98 %, based on the total weight.

2. Methionine-containing shaped bodies according to claim 1, having a methionine content of from 85 to 95 wt.%.

3. Shaped bodies according to claims 1 and 2, containing an organic and/or inorganic binder.

4. Shaped bodies according to claim 3, containing as binder potassium carbonate or potassium hydrogen carbonate, individually or together.

5. Shaped bodies according to claim 4, in which the binder comes from the mother liquor of the methionine preparation.

6. Shaped bodies according to one or more of the preceding claims, additionally containing organic binders, which include dissolved methionine, methylcellulose, ethyl-cellulose, carboxymethylcellulose, carboxyethyl-cellulose, carboxypropylcellulose, hydroxypropyl-cellulose, hydroxypropylmethylcellulose, cellulose acetate dibutylaminoacetate and other cellulose derivatives, starch, hydroxypropyl starch, sugar, dextrin, gelatin, polyvinyl alcohol, polyvinylpyrroli-done, polyvinylacetal dibutylaminoacetate, individually or in admixture with one another.

7. Shaped bodies according to one or more of the preceding claims, containing hydrophilic and/or hydrophobic silicas and/or silicate-based additives.

8. Shaped bodies according to one or more of the preceding claims, containing other feed-effective compounds such as lysine, threonine or alanine or their salts, N-acyl-amino acids, N-hydroxymethylmethionine calcium salts, 2-hydroxy-4-methylmercaptobutyric acid and other amino acid hydroxy analogues, fish meal, casein, other proteins, vitamin A, vitamin A acetate, vitamin A
palmitate, vitamin D3, vitamin E, nicotinic acid, nicotinic acid amide, pantothenic acid calcium, .beta.-carotene, individually or together.

9. Process for the production of pourable methionine-containing shaped bodies, characterised in that the water is removed from an aqueous methionine suspension down to from 8 to 40 wt.%, based on the total weight, and the solid so obtained is subjected to a shaping process, especially is extruded, and is subsequently dried.

10. Process according to claim 9, characterised in that, prior to shaping, the methionine separated from the preparation process is washed with water or, preferably, with a mother liquor taken from the preparation process.

11. Process according to claims 9 or 10, characterised in that, prior to shaping, organic and/or inorganic binders are

12 added to the methionine separated from the preparation process.

12. Process according to one or more of the preceding claims, characterised in that a silicate-like filler, especially a hydrophilic or hydrophobic silica, is added to the methionine prior to shaping.

13. Process according to one or more of the preceding claims, characterised in that one or more other feed-effective compounds are added to the methionine prior to shaping.

14. Process according to one or more of the preceding claims, characterised in that the water-containing methionine is extruded at a temperature of from 20 to 120°C, especially in a twin screw extruder, is optionally spheronized and is subsequently dried.

15. Process according to one or more of the preceding claims, characterised in that the extrudates are optionally dried on a drying belt and optionally additionally on a disk dryer at temperatures of from 50 to 140°C, optionally in vacuo.