Dipeptide-containing granular material

Abstract

The present invention relates to a process for producing a particulate composition containing methionine, methionylmethionine, potassium in the form of potassium salt and ammonium sulphate, and use thereof.

Claims

1. A process for producing a particulate composition containing methionine, methionylmethionine, potassium salt and ammonium sulfate, the process comprising: generating particles from an aqueous mixture by a forming process with upstream and/or simultaneous evaporation of the water; and drying the particles to obtain the particulate composition, wherein the aqueous mixture comprises: 0.5 to 4% by weight of methionine, 0.5 to 5% by weight of methionylmethionine, 1 to 9% by weight of potassium in the form of a potassium salt; and 7 to 35% by weight of ammonium sulfate.

2. The process according to claim 1, wherein the aqueous mixture comprises: 1 to 3% by weight of the methionine, 1 to 4% by weight of the methionylmethionine, 2 to 7% by weight of the potassium in the form of the potassium salt, and/or 10 to 30% by weight of the ammonium sulfate.

3. The process according to claim 1, wherein the aqueous mixture is produced by mixing an aqueous solution (i) comprising 30 to 40% by weight of the ammonium sulfate with an aqueous solution (ii) comprising: 2 to 6% by weight of the methionine; 4 to 8% by weight of the methionylmethionine; and 6 to 14% by weight of the potassium in the form of the potassium salt, such that a ratio of the aqueous solution (ii) to the aqueous solution (i) is from 1.0/0.5 to 1.0/3.0.

4. The process according to claim 3, wherein: the aqueous solution (i) comprises 30 to 40% by weight of the ammonium sulfate; and the aqueous solution (ii) comprises: 3 to 5% by weight of the methionine, 5 to 7% by weight of the methionylmethionine, and/or 8 to 12% by weight of the potassium in the form of the potassium salt.

5. The process according to claim 3, further comprising: preparing the aqueous solution (i) comprising the ammonium sulfate primarily by treating a gaseous mixture comprising hydrogen cyanide and ammonia, generated in the production of hydrogen cyanide from methane and ammonia, with sulphuric acid and, subsequent, neutralizing a resulting aqueous solution with ammonia.

6. The process according to claim 3, further comprising: preparing the aqueous solution (ii) by separating a mother liquor formed in the reaction of 5-(2-methylmercaptoethyl)hydantoin with potassium carbonate, potassium hydrogen carbonate and carbon dioxide to give the methionine.

7. The process according to claim 1, wherein the aqueous mixture is additionally treated with sulphuric acid until a pH of 3 to 6 is reached in the aqueous mixture, measured at room temperature with a glass pH electrode filled with liquid electrolyte in the form of a 3 molar KCl solution.

8. The process according to claim 1, wherein the aqueous mixture is also concentrated, prior to performing the forming process, by evaporation of water to give an aqueous suspension with a solids content of up to 70% by weight.

9. The process according to claim 1, wherein an ammonium sulfate shell layer is applied to the particles by spraying with an aqueous solution comprising 30 to 40% by weight ammonium sulfate with simultaneous evaporation of water, such that a proportion of the ammonium sulfate shell layer formed on the particles is 5 to 30% by weight based on the total solids content of the particles.

10. The process according to claim 1, wherein the potassium salt is present as at least one salt of an inorganic or organic acid.

11. The process according to claim 10, wherein the potassium salt is at least one potassium salt formed from an acid selected from the group consisting of formic acid, acetic acid, propanoic acid, 2-hydroxypropanoic acid, 2-hydroxy-4-methylthiobutanoic acid, KHCO.sub.3, K.sub.2CO.sub.3, KHSO.sub.4 and K.sub.2SO.sub.4.

12. The process according to claim 1, wherein the forming process is carried out as a spray granulation, mix granulation, extrusion or compaction.

13. The process according to claim 12, wherein the forming process is carried out as a spray granulation with a two-phase nozzle, in which a gas component together with the aqueous mixture is sprayed as a liquid component via the two-phase nozzle.

14. The process according to claim 13, wherein air or nitrogen are used as a gas component.

15. The process according to claim 13, wherein the forming process occurs in a fluidized bed at a temperature of 60 to 130° C.

16. A particulate composition, comprising: 5 to 10% by weight of methionine; 2.5 to 9% by weight of methionylmethionine; 4 to 20% by weight of potassium in the form of a potassium salt; and 27 to 80% by weight of ammonium sulfate.

17. The composition according to claim 16, comprising: 2 to 8% by weight of the methionine, 3 to 7% by weight of the methionylmethionine, 5 to 17% by weight of the potassium in the form of the potassium salt, and/or 30 to 76% by weight of the ammonium sulfate.

18. The composition according to claim 16, wherein the potassium salt is at least one potassium salt formed from an acid selected from the group consisting of formic acid, acetic acid, propanoic acid, 2-hydroxypropanoic acid, 2-hydroxy-4-methylthiobutanoic acid, KHCO.sub.3, K.sub.2CO.sub.3, KHSO.sub.4 and K.sub.2SO.sub.4.

19. The composition according to claim 16, further comprising: a binder selected from the group consisting of a porous volcanic silicate rock, a precipitated silica, a fumed silica, and a porous carbonate rock.

20. The composition according to claim 16, wherein: particles of the particulate composition have been coated with an ammonium sulfate layer; and a proportion of the ammonium sulfate layer is 5 to 30% by weight, based on the total solids content of the particles.

21. A fertilizer or fertilizer additives, comprising the particulate composition of claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For the purpose of better illustrating the advantages and properties of the claimed invention, several graphs are attached as non-limiting examples, wherein:

(2) FIG. 1 illustrates an apparatus for carrying out a spray granulation.

(3) FIG. 2 shows sulphur content in the gas phase via the spray granulates.

(4) FIG. 3 shows storage characteristics of the spray granulates with variation over time in a climate cabinet (20° C., 40% rh).

EXAMPLES

(5) Suitable Apparatus and General Description of the Performance of the Process

(6) The spray granulations were carried out with the aid of a fluidized bed system. The principle set-up of a fluidized bed system is shown schematically in FIG. 1. The process chamber (vortex chamber) consists of a conical vessel with sieve trays (diameter here=150 mm, mesh size=100 μm). In the middle of the sieve tray is a two-phase nozzle (nozzle diameter here=1.2 mm) with two inlet nozzles. The solid/liquid mixture is metered in via one nozzle by means of a pump (e.g. peristaltic pump). Compressed air is supplied via the second nozzle in order to finely distribute the liquid in the process chamber and to spray onto the fluidized bed present therein (fluidized solid). At the same time, hot air (or nitrogen) is allowed to flow from bottom to top in the apparatus in order firstly to fluidize the material present and secondly to evaporate the sprayed liquid. The solid sprayed ideally remains adhered to the particles present whereby a discrete particle growth can be adjusted. The particle size to be achieved in the discharge is dependent on the nucleus balance in the fluidized bed system. This is determined essentially by the equilibrium of nucleation by abrasion or non-impinging spraying droplets, and the construction of granules. The particle size can be adjusted in a controlled manner by selecting the drying and spraying parameters and by the use of a chopper in the fluidized bed. The granules thus generated can be discharged continuously from the drying chamber in the desired particle size by a classifying unit (e.g. sifter and underflow weir).

(7) The air required for drying and fluidizing is sucked in using a fan and is heated to the desired supply air temperature by an air heater (e.g. electrical, gas or steam heating). By means of the exhaust air fan, the pressure in the system is regulated. Owing to the diameter of the vortex chamber becoming larger, the speed of the gas decreases over the system height, whereby the discharge of fine particles from the system is reduced. Discharged particles are recycled into the system via a dust extractor (e.g. 6 cartridge filters) by releasing these from the filter elements pneumatically with compressed air. As an alternative to a filter separator, a cyclone or a cyclone/filter combination and wet scrubber may also be used.

(8) The dried residue of the solution (ii) previously mentioned or the mother liquor from the hydantoin hydrolysis circulation described above served as carrier material (starting fill), which had been previously comminuted using a screen mill (e.g. mesh size=150 μm). As an alternative, methionine powder (particle size d50=180 μm) or Ekoperl—an oil binder composed of porous volcanic silicate rock (Perlite) with grain size 0.125 to 2 mm—can be used as starting material.

(9) The suspension to be sprayed was a mixture of the evaporated solution (ii) mentioned above or the mother liquor of the hydantoin hydrolysis circulation mentioned at the outset (ca. 40% by weight dry mass) and an ammonium sulphate solution (solution (i) with a dry mass of ca. 30 to 40% by weight), which had been homogenized with the aid of a stirrer.

(10) For the examples, several spray granulation experiments were carried out using various mixing ratios (solution (ii): solution (i) of 1:2, 1:1; 1:0.8 and 1:0.6) in the apparatus described above. Aqueous solution (i): 35% by weight ammonium sulphate Aqueous solution (ii) 4.6% by weight methionine, 6.3% by weight methionylmethionine, 9.7% by weight potassium

(11) In order to avoid addition to the spray nozzle of coarse solid particles, the solution or suspension used was dispersed using a high-performance dispersing device (e.g. ULTRA-TURRAX®) at ca. 10 000 rpm for 5 min. Subsequently, the solution/suspension was evaporated in an evaporator (e.g. laboratory rotary evaporator) from a solids content of ca. 30 to 40% by weight to a concentration of 60 to 70% by weight.

(12) The examples were carried out in the apparatus described above according to FIG. 1 in continuous mode. Here, the following experimental parameters were set.

(13) Parameters Set in the Fluidized Bed Spray Granulation:

(14) T air supply=100-200° C.

(15) T fluidized bed=60-110° C.

(16) T exhaust air=60-130° C.

(17) Spray rate=0.3-3 kg/h

(18) Nozzle pressure (two-phase nozzle)=1.2 bar

(19) Drying air volume flow=40-200 m.sup.3/h. This corresponds to a flow velocity of 0.6-3.1 m/s at the stated inflow area (0.018 m.sup.2)

(20) System pressure above the sieve tray=10 mbar below atmospheric pressure

(21) Mean residence time: 0.5-1 h

(22) Continuous operation with discharge via a zigzag sifter

(23) Parameters Set in the Coating of the Particles:

(24) Two-phase nozzle,

(25) Nozzle pressure: 1.2 bar

(26) Spray rate: 0.3-3 kg/h

(27) P=10 mbar below atmospheric pressure

(28) T air supply=100-200° C.

(29) T bed=60-110° C.

(30) Mean residence time: 0.5-1 h

(31) Batch operation

(32) TABLE-US-00001 TABLE 1 Overview of granulation experiments Mixing ratio Coating [% by wt.] Example solution (ii)/solution based on the total solids No. (i) Binder content of the particles 1 1:1   — 10% by weight ammonium sulphate 2 1:0.8 — uncoated 3 1:0.6 — uncoated 4 1:0.6 volcanic uncoated rock, Perlite (ca. 30% by weight) 5*) 1:2   — uncoated 6 1:0, — uncoated only solution (ii) *)in Example 5 the pH of the starting mixture (prepared from solutions (i) and (ii)) was adjusted to 6 using sulphuric acid.

Examples 1 to 5

(33) The mixtures subjected to the conditions of spray granulation according to Examples 1 to 5 could be granulated to particulate compositions having particle diameters of 1-4 mm. The compositions showed in each case a low tendency to dust formation, good to very good flowability (demonstrated by laboratory shear testing; cf. Table 3) and also good product stability (demonstrated by laboratory storage tests; cf. Table 3). The granules had in each case an especially low clumping tendency, particularly if the pH of the starting mixture was lowered by means of sulphuric acid or if the particles generated were coated additionally with solution (i) (ammonium sulphate) (Example 1). The bulk density of the granules generated were from 700-800 kg/m.sup.3.

(34) The product according to Example 1 was coated in the batch process. The concentration of the ammonium sulphate layer may be determined from a mass balance assuming that a uniform wetting of the granules is ensured and no losses occur on spraying. The amount of ammonium sulphate sprayed minus the water corresponds to the proportion by mass of the ammonium sulphate coating based on the total weight of the end product.

Example 6 (Comparative Example)

(35) The solution (ii) subjected to the conditions of spray granulation did not granulate but formed a sticky mass.

(36) Product Properties Identified (Cf. Table 2):

(37) TABLE-US-00002 TABLE 2 Product properties of the granules obtained Composition Tendency [% by weight] Experiment BD Diameter to dust Clumping (Met/Met- No. [kg/l] (mm) formation Flowability tendency Met/K/(NH.sub.4).sub.2SO.sub.4) 1 0.75 1-2 slight good slight 5.2/4.4/11.7/45.6 2 0.75 1-2 slight good slight 5.5/4.6/12.2/42.8 3 0.75 1-4 slight good slight 6.5/5.5/14.6/34.2 4 0.75 1-4 high moderate slight not investigated 5 0.75 1-4 slight very slight 4.5/4.7/10.4/53.0 good 6 n.a. n.a. n.a. poor high not investigated BD: bulk density, n.a.: not applicable
Storage Stability:

(38) With the exception of the product according to Example 4, which contained a binder, the products according to Examples 1 to 3 and 5 were dust-free and remained solid and dry even after several months at normal ambient air. Only a certain caking and a moderate sensitivity to elevated air humidity were identified but these did not notably limit the practical use of the product. The caking is however sometimes even considerably lower in the granules produced with addition of sulphuric acid (Example 5) compared to the granules produced without addition of sulphuric acid (Examples 2 and 3). It is possible, therefore, to break up again the slight hardening by simple mechanical stress (e.g. tumbling, dropping of sacks).

(39) Assessment of the Odour:

(40) In order to make a statement regarding the release of unpleasant odours from the granulated product, the following laboratory tests were carried out:

(41) For this purpose, the samples were placed in a U-tube and air was passed through them. In the exhaust air beyond the U-tube, the content of sulphur compounds, which are mainly responsible for the unpleasant odour, was determined by means of a UV fluorescence sulphur analyzer (e.g. manufacturer Horiba). The results are shown in FIG. 2. By means of the integral of the respective curve calculated over the same time interval, the concentration of the sulphur components released in the exhaust gas was assessed. The greater the integral, the more sulphur components were released.

(42) In comparison to the sample from Example 6 (comparative Example), the content of sulphur compounds in the exhaust gas in the granulated product was about one power of ten lower. By irrigating the granules (e.g. by rain), the release of sulphur compounds is however increased, which was simulated by moistening the samples from Examples 1 and 2 (numbers 4 and 5 in FIG. 2).

(43) Flow and Storage Characteristics of the Granules Produced (Cf. Table 3, FIG. 3)

(44) To evaluate the storage stability, the granules were stored at defined climatic conditions (temperature and humidity) over a certain time period. Comparison of the flow properties before and after storage gives information about the storage stability of the product.

(45) To measure the flow properties, so-called shear testers were used (according to ASTM Standards D6128 “Standard Shear Testing Method for Bulk solids using the Jenike Shear Cell”). The sample of flowable solid was filled into a shear cell for the measurement. The shear cell consisted of a base ring sealed below, an “upper ring” placed thereover of the same diameter and also a lid. The lid was subjected to a central load corresponding to a 6 m silo for example. By means of moving the upper ring and the lid with respect to the base ring, the sample of flowable solid was subjected to a shear deformation. The force required for the movement was measured. From the normal force and the shear force, the normal stress (initial shear stress, flow location) and the shear stress σt were calculated by division by the cross-sectional area A of the shear cell. The sample of flowable solid filled into the shear cell in each case was sheared at various normal stresses which was adjusted by applying a particular normal force. The greatest principal stress at stationary flow σ1 (=consolidation stress) arose from the stress circle which affects the flow location and proceeds by the initial shear point. The yield strength (compressive strength) ac arose from the stress circle which affects the flow location and whose smallest principal stress is equal to zero. In contrast to the monoaxial compressive test, the yield strength was not obtained directly in the measurement with shear devices but via the indirect flow location. The bulk density pb was obtained by dividing the mass of the flowable solid in the shear cell by the volume of the shear cell (source: Dietmar Schulze, Pulver und Schüttgüter—Fließeigenschaften und (Grundlagen) Handhabung [Powders and Flowable Solids—Flow Properties and Handling (Fundamentals), Springer-Verlag, 3rd edition, 2014).

(46) TABLE-US-00003 TABLE 3 Flow and storage characteristics of the granules generated Flow Flow location Com- properties Initial Consolidation pressive Bulk Instantaneous shear stress strength density Product flow stress σ1 σc ρb from characteristics Pa Pa Pa kg/m.sup.3 Example 2900 7965 471 709 Example 2 2900 9767 734 738 Example 5 Com- Caking Storage pressive Bulk Product at initial shear Load conditions strength density from stress of 2900 Pa kg — σc ρb Example Storage period 7 20° C., 40% rh 24912 729 Example 2 24 h 7 20° C., 40% rh 4077 714 Example 5 Storage period 7 50° C., 7 kg 10413 694 Example 2 24 h 7 50° C., 7 kg 3764 693 Example 5 6 50° C., 6 kg 18763 741 Example 2 6 50° C., 6 kg 3444 712 Example 5 Storage period 7 40° C., 75% rh 21493 753 Example 2 24 h 7 40° C., 75% rh 16743 801 Example 5 Storage — h conditions Pa kg/m.sup.3 Variation of 0 20° C., 40% rh 471 709 Example 2 storage period 24 20° C., 40% rh 8184 711 Example 2 72 20° C., 40% rh 13303 723 Example 2 168 20° C., 40% rh 47797 708 Example 2 Variation of 0 20° C., 40% rh 734 738 Example 5 storage period 24 20° C., 40% rh 3444 712 Example 5 Load 6 kg 72 20° C., 40% rh 6929 722 Example 5 168 20° C., 40% rh 9780 738 Example 5 rh = relative humidity σ1 = maximum consolidation stress σc = compressive strength (=breaking stress) ρb = bulk density

(47) The compressive strength is in this case a measure of the yield strength or tendency to clumping. The higher the value of the compressive strength, the greater are the inner adhesion forces and greater is the clumping of the flowable solid. The results in Table 3 and in FIG. 3 show that the product additionally pH-adjusted with sulphuric acid prior to the spray granulation (Example 5) has even lower clumping also after weathering in the climate cabinet at 20° C. and 40% relative humidity for up to 168 h and also at extreme climate conditions (40% and 75% rh) has a better storage stability than granulate produced without prior adjustment of the pH to 3 to 6 with sulphuric acid (Example 2).