Closed Fluidized Bed Coating for Controlled Release Fertilizer
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Solution Overview
Problem
Current methods for producing controlled release fertilizers using fluidized bed coating machines face challenges with water-based coatings, including inefficient thermal energy use, humidity issues, material solidification, and difficulty in achieving consistent coating quality, especially in large-scale production.
Innovation Solution
A closed large numerically controlled fluidized bed coating machine with a fluidized drying tower and cyclone separator is used, implementing a closed air circulation system for efficient heat use, automatic feeding, and smart control of coating parameters to ensure consistent and efficient water-based coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If organic solvent coating is used in traditional fluidized bed coating machines, then coating can be applied, but thermal energy is wasted and heat consumption is high due to open air circulation system
Solution Approach 1:
The patent creates a closed circulation system that functions as a controlled environment, preventing thermal energy loss by circulating and reheating exhaust air through a heat exchanger, thereby reducing the energy required to maintain coating temperatures
Solution Approach 2:
The patent recovers thermal energy from exhaust air that would otherwise be discarded, using a heat exchanger to preheat incoming air with hot exhaust air, thereby reducing fuel consumption and improving thermal efficiency
2Temperature
If water-based coating is used with high air inlet temperature, then coating can be dried, but coating material solidifies in spray gun causing blocking
Solution Approach 1:
The patent introduces circulating water as an intermediary cooling medium that flows through the spray gun to prevent coating material solidification, enabling reliable operation with high temperature air inlet while maintaining spray gun functionality
Solution Approach 2:
The patent changes the temperature parameter of the air inlet dynamically by circulating and cooling it through water cooling, allowing the system to operate at high temperatures without causing material solidification in the spray gun
3Ease of operation
If manual control is used for coating parameters, then operation is simple, but coating process repeatability cannot meet technical requirements
Solution Approach 1:
The patent implements automated control systems with sensors and feedback mechanisms that continuously monitor and adjust coating parameters such as air temperature, humidity, and spray rate, ensuring consistent coating quality and process repeatability while maintaining ease of operation through centralized control
4Ease of manufacture
If uncontrolled humidity is present during water-based coating, then coating can be applied, but coating quality is affected and environmental effects occur
Solution Approach 1:
The patent creates a controlled humidity environment during water-based coating by managing air circulation and dehumidification, preventing uncontrolled humidity from affecting coating quality while maintaining a simple coating process through automated environmental control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces energy consumption, widens the scope of applicable materials, and enhances coating process repeatability, addressing issues of thermal efficiency, humidity control, and material handling in large-scale production.
Implementation Method 1
a fluidized drying tower with a dehumidifying function... the wet and hot air from the ID fan to flow through a cyclone separator to remove impurities, and be dehumidified in a fluidized drying tower
Implementation Method 2
the wet and hot air from the ID fan to flow through a cyclone separator to remove impurities
Implementation Method 3
the external air is heated via a steam heat exchanger and flows into the coating machine main tower
Data Source
AI summary
Disclosed is a method for making a controlled release fertilizer with water-based coating using a closed large numerically controlled fluidized bed and a device therefor: collecting a granular fertilizer with a suitable granule size into a barrel; sucking the same into a coating cavity by negative pressure and making the same fluid; directing a water-based coating liquid into a spray gun, then spraying the liquid onto the surface of the fertilizer granules after nebulization; collecting the impurities in the air discharged from the coating cavity by means of a cyclone separator; dehumidifying the air discharged from the cyclone separator by means of a fluidized drying tower; and then the coating is completed. The closed large numerically controlled fluidized bed coating machine has a fluidized bed coating machine main tower, a cyclone separator, a fluidized drying tower, a blower, a heater, an air compressor, a coating liquid inlet system and a control system, and is characterized in that it has a closed air circulation system, and is provided with a dehumidifying mechanism and a water condensing mechanism for the fluidized drying tower. The present invention can reduce energy consumption, increase heating efficiency and has moisture-absorbing function; it can prevent the spray gun from blocking; it has the function of automatic feeding, which improves the efficiency of coating; therefore it is important for the achievement of a water-based coating process.