Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/14—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic in rotating dishes or pans
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
  • A01N25/12—Powders or granules

Definitions

• Pan granulating has been used extensively for granulating ores and raw meal for cement kilns. In this process, a pan granulator is used to mix a solid particle with a liquid, usually water, to form
• pan granulator it is also known in the art as an inclined dish granulator, a disc granulator, a granulating table, an inclined pan, or a coating pan.
• pan granulating is that the liquid applied during the granulation step must be removed in a drying step.
• drying step is the slowest step in the process and is often the capacity-limiting feature.
• pan granulating can be improved if sufficient saturated or superheated steam is applied to the ingredients on the surface of the rotating pan to raise their temperature to 30-120°C, preferably 35-70oC.
• This steam reduces the amount of liquid necessary for granulation, thereby requiring less drying time for the product granules.
• the process is particularly useful in granulating ingredients that normally require large amounts of moisture during glcanulation.
• the improved process of the invention can be used to granulate many materials. It is particularly useful to granulate crop protection chemicals. When these materials are granulated with steam, the resultant granules display optimum properties such as rapid dispersion in various fluids (e.g., water) and attrition resistance.
• various fluids e.g., water
• the Figure is a view of a conventional pan granulator having means for applying steam to the ingredients on the surface of the pan.
• the invention relates to an improved process for pan granulation by the simultaneous application of heat and moisture, in the form of saturated or superheated steam, to the tumbling ingredients on the surface of the rotating pan.
• An apparatus useful in the process of the invention will be described with reference to the Figure.
• a shallow cylindrical pan 1 is attached to a base support 2 and rotated about an inclined axis. The rotation is accomplished by a drive means (not illustrated) which is operably connected to the pan 1 through the axle 3.
• the angle of inclination and the speed of rotation of the pan are usually variable and are adjusted as is conventional to produce the desired size granule.
• the ingredients that are granulated on the pan are a mixture of solids and liquid, usually water.
• the solids are supplied to the surface of the pan through a discharge means 4 and liquid is supplied by spray means 5.
• the solids can be either one material or a mixture, and often it is desirable to premill to a particle size between 2 and 30 microns.
• the solids can also be supplied partly by a recycle of over- or undersized granular product.
• the liquid be sprayed on a moving bed of the solid materials and absorbed and not sprayed on the surface of the pan.
• the spray droplet size is determined in the
• the granulator can also contain a side wall scraper 6 and a bottom scraper 7 to prevent build up of the ingredients on the pan surfaces.
• the bottom scraper can be of the reciprocating type and also can serve to maintain a uniform deposit of material on the surface of the pan.
• ingredients are mixed and treated with the steam, granules grow in size and the largest granules overflow from the bottom edge of the pan in the usual fashion.
• the pan angle and rotation rate are selected using known relationships to provide the desired granule formation.
• the amount of water added is determined based on the desired granule size.
• moisture requirement for the desired granule size is reduced by as much as 30 to 40%, and preferably at least 20% .
• the pan is rotated clockwise with the steam nozzles located near where the granules overflow. As this pan rotates, after the steam addition, the water is added and then the premix of solid ingredients.
• crop protection chemical is intended to refer to biologically active compositions
• These chemicals are commonly known as herbicides, fungicides, insecticides, nematocides, acaricides, miticides, virucides, algicides, bactericides, plant growth regulants and their agriculturally suitable salts. These chemicals may be water-soluble or water-insoluble and may be solid or liquid at room temperature, providing the liquids are first adsorbed onto solid carriers before granulation. Examples of suitable crop protection chemicals are shown in, but not limited to. Table I.
• a conventional pan granulator (Mars Mineral DP14), after being modified for steam addition, was employed to produce herbicide granules.
• Water was first added to the pan at a rate such that the moisture content was 15% by weight. Thereafter the water feed was reduced to produce a moisture content of 11% by weight and sufficient steam added to raise the temperature of the ingredients in the pan to 32°C. The addition of the steam reduced the drying time from about 10 minutes to 7 minutes and the observed quality of the granular product was good.
• the granule size ranged from about 500 to 3000 microns.
• pan granulator (Teledyne Corp.), after being modified for steam addition to the pan, was employed to produce herbicide granules. Diameter of pan 91.4 cm
• the granulation was reduced from 18-20% with water to 11-13% when steam was added at a rate to produce a material temperature in the pan of 65-75°C.
• the drying time was reduced from about 8 minutes to 6 minutes by the use of steam.
• the granule size ranged from about 300 to 3000 microns and the granules were uniformly spherical in shape.
• the moisture requirement for pan granulation was reduced from 18-20% with water to 11-14% when steam was used to increase the material temperature in the pan to 65-70°C.
• the drying time was reduced from about 8 minutes to 6 minutes.
• the granules ranged in size from about 300 to 3000 microns and the granules were uniformly spherical in shape.

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Plant Pathology (AREA)
• Pest Control & Pesticides (AREA)
• Agronomy & Crop Science (AREA)
• Toxicology (AREA)
• Engineering & Computer Science (AREA)
• Dentistry (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Environmental Sciences (AREA)
• Agricultural Chemicals And Associated Chemicals (AREA)
• Glanulating (AREA)
• Led Device Packages (AREA)
• Magnetic Ceramics (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

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Family Applications Before (1)

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• 1990
  • 1990-04-23 IL IL94169A patent/IL94169A0/xx unknown
  • 1990-04-24 KR KR1019910701427A patent/KR920700756A/ko not_active Withdrawn
  • 1990-04-24 CN CN90104133A patent/CN1047220A/zh active Pending
  • 1990-04-24 EP EP90304390A patent/EP0395354A1/de not_active Withdrawn
  • 1990-04-24 WO PCT/US1990/002123 patent/WO1990012643A1/en not_active Ceased
  • 1990-04-24 AU AU55294/90A patent/AU647387B2/en not_active Ceased
  • 1990-04-24 JP JP2506498A patent/JPH06509496A/ja active Pending
  • 1990-04-24 CA CA002015295A patent/CA2015295A1/en not_active Abandoned
  • 1990-04-24 NZ NZ233432A patent/NZ233432A/en unknown
  • 1990-04-24 BR BR909007314A patent/BR9007314A/pt not_active Application Discontinuation
  • 1990-04-24 EP EP90906704A patent/EP0470129A1/de active Pending
  • 1990-04-24 HU HU903636A patent/HU209073B/hu not_active IP Right Cessation

Non-Patent Citations (1)

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