Classifications

• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05C—NITROGENOUS FERTILISERS
  • C05C9/00—Fertilisers containing urea or urea compounds
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05C—NITROGENOUS FERTILISERS
  • C05C9/00—Fertilisers containing urea or urea compounds
  • C05C9/005—Post-treatment
• • C—CHEMISTRY; METALLURGY
  • C05—FERTILISERS; MANUFACTURE THEREOF
  • C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
  • C05G5/00—Fertilisers characterised by their form
  • C05G5/30—Layered or coated, e.g. dust-preventing coatings

Definitions

• the invention relates to a method for producing granular fertilizer containing urea and sulfur, and more particularly to a method for producing granular urea with dispersed particles of elemental sulfur in the volume of the granule.
• fertilizers containing urea and elemental sulfur in which sulfur is distributed in the volume of the fertilizer granule in a finely dispersed (less than 100 ⁇ m) state, is that finely dispersed sulfur is more rapidly oxidized by sulfobacteria into a form accessible to plants, which increases the efficiency of the fertilizer applied.
• a known method of producing granular fertilizers containing urea and elemental sulfur in which the urea melt is mixed with a sulfur melt in the presence of special additives (resistant to temperature C 6 - C 30 fatty acids and their esters) (RU 2296730, C05C 9/00, 2007) .
• the resulting homogeneous phase is then solidified to obtain solid granules.
• the time interval between the introduction of additives and obtaining solid granules should be less than 180 C.
• fertilizer granules are obtained in which sulfur is distributed in the granule volume in a finely divided state.
• the particle size of sulfur is approximately 10-150 microns and depends on the concentration of additives.
• the urea melt and the sulfur melt are mixed prior to granulation in the presence of special additives.
• This requires introducing into the method of fertilizer production an additional stage of mixing the melts and, as a result, introducing an additional apparatus (mixer) into the plant for the production of fertilizer. All this leads to a complication of the technology, as well as additional costs associated with the need to use additional substances. But, as mentioned above, these measures do not lead to the formation of a time-stable system.
• Closest to the proposed method is a known method for producing granular fertilizer containing urea and elemental sulfur, which includes obtaining a homogenized melt of urea and sulfur and spraying it onto retur particles consisting of urea and sulfur in the volume of a rotating inclined drum (US 4330319, ⁇ 05 ⁇ 9 / 00, 1982).
• fertilizer granules are obtained in which sulfur is distributed in the granule volume in a finely divided state.
• the sulfur particle size is less than about 100 microns.
• the urea melt and sulfur melt are passed through one or several devices for high-intensity mixing at temperatures above the melting points.
• the pressure drop through said mixing device is at least 200 kPa.
• a homogenized urea-sulfur melt is a very unstable system.
• the two liquid components of the melt significantly differ in surface tension and density and, thus, tend to immediately delaminate into two separate phases.
• AT The description of this known method indicates that it is desirable to keep the residence time of the homogeneous melt before solidification as short as possible: the time that elapses between the exit of the homogenized melt from the mixing device and the solidification should be of the order of 10 seconds or less. Only under this condition is achieved the distribution of sulfur in the volume of the granule and the production of sulfur particles in the final fertilizer with a size of less than 100 microns.
• the technical problem to which this invention is directed is to simplify the technology for producing granular urea with elemental sulfur distributed in the volume of the granule.
• a method for producing granular fertilizer containing urea and elemental sulfur by spraying urea and sulfur in a liquid state onto a curtain of granular material in the volume of a rotating drum characterized in that the spraying is carried out in a drum with blades mounted on its inner surface.
• the sulfur melt and the urea melt or solution are sprayed simultaneously with two separate disjoint circular torches with diameters approximately equal to half the diameter of approx guns formed by the free ends of the blades of the drum, and the spraying of the urea and sulfur melts is carried out along the axis of rotation of the drum in one direction.
• the technical result that occurs when using the invention is to ensure the distribution of sulfur in the volume of the granule of the fertilizer in a finely divided state without preliminary mixing of the components.
• This result is achieved using the inventive method of applying a sulfur melt and a melt or urea solution to granules.
• the curtain of falling granules which are newly introduced prilled urea and retur (particles with a size less than required), is irrigated with two disjoint torches of circular cross section with diameters approximately equal to half the diameter of the circle formed by the free ends of the blades.
• each granule is alternately subjected to irrigation with a sulfur melt and a melt or urea solution.
• the melt or urea solution in this case is a binder component of sulfur particles.
• Urea binds sulfur particles by coating with thin films during pelletizing.
• FIG. 1 shows a longitudinal section of a drum granulator, which can be used to implement the proposed method.
• FIG. 2 shows a cross section of a drum AA.
• FIG. 3 schematically illustrates the nature of the movement of the granules according to the proposed method in the cross section of the drum BB.
• the drum granulator comprises a drum 1 with a conveying nozzle in the form of distribution blades 2 mounted on the inner surface in several rows, a loading chamber 3 and an unloading 4, which are fixed relative to the rotating drum.
• the loading chamber 3 contains a loading pipe 5, an air outlet fitting 6, a mechanical nozzle 7 and a mechanical nozzle 8 located parallel to the axis of the drum in the direction of the discharge chamber.
• the discharge chamber 4 contains an air inlet fitting 9 and an outlet fitting for the finished product 10.
• the apparatus also contains an additional external drum 11, a return screw 12 located between the drums and rotating with them, a classifier 13 fastened to both drums, and receiving windows 14.
• the casing 15 with partitions 16 and cooling water supply fittings 17 and cooling water drain 18 is made outside the outer drum 1 1 so in such a way as to ensure water cooling of the surface of the drum and, consequently, of the product returned as retur to the zone of the falling curtain of granules.
• the proposed method is implemented in the granulator shown in FIG. 1 as follows. Prilled urea, fed through a pipe 5, mounted in a fixed loading chamber 3, enters a drum 1 equipped with a transporting nozzle 2. When the drum rotates, the nozzle blades 2 lift and eject product particles along a parabolic path in the drum cross section to form a dense and uniform curtain falling particles of the product. At the same time, sulfur melt and a urea solution and two non-intersecting circular torches with diameters approximately equal to half the diameter of the circle formed by the free ends of the blades are sprayed into the front of the drum 1 onto the formed curtain of falling particles by means of nozzles 7 and 8 along the drum axis in the direction of the discharge chamber .
• the granules of the required size, reaching the end of the classifier, fall into the discharge chamber 4 and in the form of the finished product through the nozzle 10 are removed from the apparatus.
• a small fraction of the product passes in the classifier 13 into the space between the inner 1 and the outer drums and, using the screw 12, is transported to the front of the outer drum 11 to the receiving windows 14, through which the product enters the inner drum 1 for further growth in a falling curtain.
• the granules acquire a smooth smooth surface (without bumps).
• To remove heat in the fitting 17 of the casing 15 Provided (if necessary) supply of cooling water with a temperature of 22 28 C.
• the invention is also illustrated by examples of the proposed method.
• Example 1 Prilled urea from a granulation tower with a temperature of 60 ° C in an amount of 1.2 t / h is fed into the drum granulator through a loading tube 5. The rotational speed of the drum is 27 rpm.
• a sulfur melt with a temperature of 127 ° ⁇ is supplied in an amount of 2.5 t / h using a pump, and carbamide melt with a temperature of 135 ° ⁇ and an amount of 6.4 t is fed through a pump 8 with a pump / h
• the sulfur melt through the nozzle 7, and the urea melt through the nozzle 8 are sprayed onto the formed curtain of urea granules and retur.
• droplets of sulfur melt and carbamide melt fall and solidify on the granules.
• Example 2 The process is carried out analogously to example 1 with the difference that prilled urea is fed from a warehouse with a temperature of 20 ° C in an amount of 1.3 t / h, the drum rotation speed is 30.5 rpm, the sulfur melt is at a temperature of 123 ° C fed in the amount of 1.3 t / h through the nozzle 7, and in the nozzle 8 serves 98% solution of urea with a temperature of 134 ° C and in the amount of 7.4 t / h Moisture evaporated from the urea solution is removed by the air supplied to the granulator. The resulting fertilizer is discharged from the apparatus in an amount of 9.9 t / h with a temperature of 70 ° C. The sulfur content in the finished product is 13.0%.
• Example 3 The process is carried out analogously to example 1 with the difference that prilled urea is supplied from a granulation tower with a temperature of 37 ° C in an amount of 1, 2 t / h, the drum rotation speed is 30 rpm, the sulfur melt with a temperature of 125 ° C is served in the amount of 0.7 t / h, melt urea with a temperature of 136 ° C is fed in an amount of 7.6 t / h The resulting fertilizer is discharged from the apparatus in an amount of 9.5 t / h with a temperature of 85 ° C. The sulfur content in the finished product is 7.4%.
• Example 4 The process is carried out analogously to example 1 with the difference that prilled urea is supplied from a warehouse with a temperature of 20 ° C in an amount of 1.2 t / h, the drum rotation speed is 29.5 rpm, the sulfur melt with a temperature of 124 ° C served in the amount of 2.1 t / h through the nozzle 7, and into the nozzle 8 serves 96% urea solution with a temperature of 137 ° C and in the amount of 7.1 t / h Moisture evaporated from the urea solution is removed by the air supplied to the granulator. The obtained urea with the addition of sulfur is discharged from the apparatus in an amount of 10.1 t / h with a temperature of 68 ° C. The sulfur content in the finished product is 20.8%.
• the invention relates to a method for producing granular fertilizer containing urea and sulfur, and can be used in the production of fertilizers.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Pest Control & Pesticides (AREA)
• Fertilizers (AREA)

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• 2012
  • 2012-01-17 RU RU2012101574/13A patent/RU2484072C1/ru not_active IP Right Cessation
  • 2012-12-27 IN IN5928DEN2014 patent/IN2014DN05928A/en unknown
  • 2012-12-27 UA UAA201407173A patent/UA110740C2/uk unknown
  • 2012-12-27 WO PCT/RU2012/001132 patent/WO2013109167A1/ru active Application Filing

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