FI62210C - FRAMSTAELLNING AV FODERUREA MED RETARDERAD VERKAN - Google Patents

Description

62210

Manufacture of slow-acting feed urea

The invention relates to a process for the preparation of slow-acting feed urea, the object of which is to reduce the adverse effects of urea when fed to animals.

It is known that ruminants are able to synthesize urea into animal protein with the help of small organisms in their rumen.

Thus, urea has long been used as an animal nutrient, either in part or in full, to replace proteins in animal feed. However, it is harmful for animals if urea is broken down too quickly in the rumen of the animal and the resulting ammonia is absorbed in large amounts into the body.

The decomposition reaction is: (1) h2o + co (nh2) 2 —-reaasl> 2NH3 + co2

The reaction takes place rapidly, in 1-2 hours, by the enzyme urease secreted by the microbes.

Rumen microbes use urea as a source of nitrogen from which they form microbial protein: (2) NH3 -λ microbial protein

The microbial protein is then degraded by the animal's proteolytic enzymes and the products are absorbed in the small intestine.

If ammonia develops suddenly and in large quantities, the animal's body can be poisoned. Therefore, various ways have been developed to slow the release of ammonia.

For example, grain and urea have been mixed using water addition at 160 ° C to a solid mass.

Starch grains break and urea crystals break down during processing. The resulting product has a slower release of NH 2 62210 than the untreated product.

It is also known to incorporate urea into furfural, in which case the rate of ammonia release from the product is about 1/7 of what it is from powdered urea (Salo, M-L, Feed Studies, Department of Animal Science, University of Helsinki, Moniste 1971).

A weakly ground, dry peat powder has been used as a carrier for urea, into which urea is absorbed (FI patent 40 135). One method provides a urea-containing feed which, when administered to animals, causes a delayed release of ammonia in the rumen of the animal. In this case, the urea is coated with hardened tallow or hardened marine animal fat. (FI patent 57 201).

However, the above-mentioned feed ureas have not proved to be reliable and have therefore not gained popularity among farmers and stockbreeders. In addition, methods of making these feed ureas have proven cumbersome and expensive.

It is therefore an object of the present invention to provide a process for the preparation of a reliable, slow-acting feed urea which can be administered to animals either as such or in addition to other feed, and which is a much more economical process.

The main features of the invention appear from the appended claim 1.

Thus, it has now surprisingly been found that the addition of an aqueous solution of formaldehyde and urea to molten urea slows down the decomposition of urea and thus the release of NH 4 in the rumen of a ruminant in a particularly advantageous manner. It is particularly advantageous to add an aqueous solution of formaldehyde and urea to the molten urea before the prilling step as an aqueous solution containing 30-60% formaldehyde and 15-30% urea. For example, the solution UF 65 contains 17.8% urea, 49.5% HCHO and 32.7% 62210 3 from IVO. In this case, the UF-65 solution is added in the normal urea process before prilling, which reduces the amount of water when it evaporates almost completely during prilling. In addition, it has been found that when formaldehyde is added to molten urea as an aqueous solution of urea-formaldehyde, urea-formaldehyde complexes are formed which have a very particularly advantageous effect of slowing down the decomposition of urea.

Two groups of reaction products of urea and formaldehyde are known: - urea resins, and - urea forms.

The molar ratio of urea to formaldehyde in the reaction mixture determines the quality of the product.

The following reactions occur in urea resin syntheses:

NH2 NH-CH-OH

I I Z

(3) C = O + CH «0 -> C = O monomethylol urea NH2 NH2

NH NH · CH_OH

1 'i 2 (4) C = O + 2 CH_0 -> C = O dimethylol urea

'I I

nh2 NH * CH2OH

In the condensate reactions, chain and network compounds are formed through ether bridges and methylene bridges.

The formation of urea forms takes place as follows:

NH- NH - CH- - NH

I 4 t Z, (5) 2 C = O + HCHO -> C = O C = 0 + H ~ 0 * I I ^ NH2 NH2 NH2

Methylene diurea 6221 0 4

The reactions in Ureaa are similar (Chaon, T.Y. George "Urea, its properties and manufacture, Chaos institute 3014 Larkwood St. West Covina, Calif. Printed in Taipei Taiwan 1967, pp. 145-151).

It is probable that the reaction results of urea and formaldehyde or one of them act as an inhibitor of the urease enzyme and thus the urea is not degraded very rapidly in the rumen of the animal. Rumen fluids may play a part in this surprising phenomenon.

Urea produced by the process of the invention, the "glasses" of which are smaller than those made for fertilizer purposes, also does not clump as easily as urea alone without the addition of formaldehyde.

In addition, it was found that the use of the additive according to the invention reduces the dust emission by about half during the prilling of low-content feed urea.

The invention is described in more detail below by means of examples. Example 1

The test substance was a UF 54 solution containing 37.5% formaldehyde, 16.7% urea and the rest water.

The test run consisted of two feed-urea run cycles of about one hour, I without additive and II with UF 54 additive, in order to determine the agglomeration properties of the product with a view to possible bulk transports. The UF 54 additive was fed to the urea melt circuit by a membrane pump.

6221 C

5

Trial period I II

Additive (% CH 2 O) - 0.18

Melting point ° C 143 143

Product temperature at the bottom of the tower (° C) +7 +6

Outdoor temperature (° C) - 2 - 2

During each experimental period, intermittent samples of the product were collected for laboratory studies.

The results are given in Table I.

Table I

Dust and NH 2 emissions from the prillation tower when running feed urea + UF 54

Flow __ m Vh mg / iV kg / h mg / m ^ kg / h 51623 733.5 37.87 57.3 2.96 55515 1132.5 62.87 65.1 3.61 56731 751.3 42.62 54.5 3.09 57306_689.8 39.53_34A_1.95

Issue 182.9 11.61

Both treated and untreated feed urea meet the quality requirements for feed urea in terms of impurities.

The untreated product packed in the bag forms a uniform lump within a short storage time, the hardness of which increases as the weight on the bag increases. However, the lump is crushed into free-flowing glasses when the sack is dropped on different sides. The product treated with UF 54 solution agglomerates considerably less than in the untreated bag, and even in a weighed bag the product remains almost fluid or becomes fluid when the bag 6 62210 is moved. In the 1-month laboratory test, the caking value of a sample of feed urea treated with UF 54 is 1/10 of that of the untreated sample.

Example 2

Except for the prevention of urea clumping, where a formaldehyde addition of about 0.2% is good, the effect of formaldehyde addition on the retardation of ammonia release in the rumen of an animal is shown below. The example demonstrates the effect of formaldehyde on urease enzyme activity on a laboratory scale.

On a laboratory scale, urea batches containing different concentrations of HCHO (0-10%) were prepared by adding a solution of UF 86 (26.1% urea, 59.9% HCHO and 14% t 2 O) to the urea melt in a glass reactor. The reaction was allowed to proceed for about 3 minutes, after which the reaction mixture was cooled and crushed into granules. The manufacturing conditions correspond to the process conditions of the urea plant. Table II shows the amounts of UF 86 and urea required for products with different HCH0%.

Table II

UF 86 and urea quantities required for different urea-formaldehyde products with HCH0%

Product UF 86 Urea Dry HCH0% amount incl. HCHO incl. Urea amount of product (g) (g) (g) (g) amount (g) 0.5 4.17 2.5 1.09 496.4 500 1.0 8 .35 5.0 2.18 492.8 500 1.5 12.52 7.5 3.27 489.2 500 2.0 16.69 10.0 4.36 485.6 500 3.0 25.05 15.0 6 , 54,478.5,500 5.0 41.74 25.0 10.86 464.1 500 10.0 83.48 50.0 21.78 428.2 500

6221 O

400 mg of urea or urea + HCHO (i.e. 2 g / l) were weighed into 7,200 ml of rumen fluid. The test solutions were incubated at 39 ° C and sampled 1/2 h, 1 h, 2 h, 4 h, Id, 2 d and 5 d from the onset. Sampling was performed as follows: Approximately 10 ml of test solution was poured into a centrifuge tube and the precipitate was separated by centrifugation. The nearly clear solution was pipetted into a 5 ml volumetric flask and diluted to volume. From the above dilution, the amount of solution required for the determination of NH 4 was taken with a syringe equipped with a microfilter to eliminate residual turbidity. The clear solution was determined colorimetrically by the NH 4 phenol hypochlorite method. The results are shown in Table III.

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Thus, it can be stated that the addition of formaldehyde to the urea melt slows down the release of NH 4 from urea in the rumen fluid. With an addition of 0.5-2% HCHO, the initial release of NH 4 (up to about 1 h from dosing) is similar to that of pure urea. With larger additions, however, already at this stage a slower, 2 h after dosing, a maximum concentration of NH 2 Sn is reached with pure urea; then the HCHO-urea products have a NH4 concentration of only 75-40% of the corresponding to HCHO additions of 0.5-10%. In the treated products, decomposition continues for 2-5 d.

Claims (2)

6221 0 A process for the preparation of a slow-acting feed urea which, in addition to urea in a partial form, contains a reaction product of urea and formaldehyde which inhibits the degradation of urea in the gastrointestinal tract of an animal by reacting a formaldehyde with a formaldehyde an aqueous solution of formaldehyde and urea is mixed with molten urea, which is finally granulated. A process according to claim 1, characterized in that an aqueous solution of about 30-60% formaldehyde and about 15-30% urea is added to the molten urea.