Process and equipment for manufacturing polymer enveloped control-released fertilizer

Abstract

The invention discloses a technics and device belong to material covering technical field for producing polymer envelop with a high molecule for controlled release of fertilizer adopting spray precipitated phase conversion method. The method firstly makes the material grain in a stable circulating fluidized state and then coats the membrane preparation liquid such as organic polymer to the moving grain surface by double-fluid blow head to prompt the phase splitting of the solvent and solute of the membrane preparation liquid which deposits on the grain surface by the means such as heat air. The solvent is volatilizing from the liquid phase to the air phase. The solute transfers from the highly dispersed liquid phase to a solid phase with a transparent film structure. The device comprises: air electric heater, spouted fluidized bed, condensator, solvent absorbing flume and collector thereof, reaction kettle for heating and blending at a constant temperature, double-fluid blow head and circuit thereof and automatic control system. The technics and device is suitable for atomizing and depositing the different envelop liquid containing polymer with a high molecule on the urea or complex fertilizer grain to produce the controlled release of fertilizer with an envelop whose releasing period is 1-9 months.

Description

technical field [0001] The invention belongs to the technical scope of material encapsulation, and in particular relates to a technique and equipment for producing polymer-encapsulated controlled-release fertilizers by using a spray precipitation phase inversion method. The process and equipment are suitable for atomizing and precipitating various coating liquids with high molecular polymers as main materials onto fertilizer particles to form films with controlled-release properties, and producing coated fertilizers with controlled-release properties. The process and equipment are mainly used for granule surface film, and are especially suitable for spraying and wrapping organic polymer on the surface of fertilizer granule to produce film-coated controlled-release fertilizer. Background technique [0002] Controlled release technology can effectively control the release process of nutrients contained in fertilizers, so as to better adjust the action intensity and action time...

AI Technical Summary

Problems solved by technology

At present, in the field of fertilizer coating, there are patents related to fluidized bed equipment applied for: in 1991, Shirley et al. developed continuous coating fertilizer production equipment. The front and back of the equipment are connected by four chambers, and the bottom is an air distribution plate. Ensure that the fertilizer particles are in a fluidized state, and advance room by room, and discharge from the outlet of the fourth room. The granular fertilizer is coated during this fluidization process (U.S. Pat. No. 5211985); invented by the Beijing Academy of Agriculture and Forestry in 2004 The "granule continuous coating equipment" (Chinese patent: 03256417.1), this equipment emphasizes that a gate valve that can be opened and closed is set in the jet flow tower to realize the transfer of particles from one tower to another; these continuous production equipment run The instability in the medium limits its application in practice, while the batch single-chamber fluidized bed is still the main equipment used in actual production

In 2005, Shandong Agricultural University conducted in-depth research on coating liquid configuration equipment, and developed the "high-pressure airflow rapid heating thermostat" (Chinese patent: 200420096624. Patent: 200420096625.4) is used to heat the coating material, which improves the performance of the traditional solution tank, but does not improve the performance of the fluidized bed coating equipment as a whole

However, in the existing patents, there are no related process methods and equipment inventions aimed at this

[0005] A large amount of organic solvent needs to be used when preparing the coating solution. Generally, the concentration of the coating solution (polymer material mass kg / solvent volume L) is about 5%. If the coating rate (polymer mass kg / fertilizer mass kg) is 5% calculation, for every ton of coated fertilizer processed, it needs to consume 1m 3 Solvents, so solvent recovery is very important to reduce costs and protect the environment, but this part was not included in the past processes and equipment

[0006] With the research and development of coating material system and processing technology, the process of preparing coated controlled-release fertilizers by spray precipitation phase inversion method has become more and more common, and the fluidized bed has become the equipment for developing and producing coated controlled-release fertilizers, but The above process and equipment problems have limited its further development

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