Segmented Urea Feed for Additive Control
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Solution Overview
Problem
The existing urea fluid-bed granulation process lacks accuracy in determining and controlling the additive concentration, particularly for additives like formaldehyde, which is high and poses environmental concerns in agricultural use.
Innovation Solution
A process where the urea solution is introduced into a fluidized bed through multiple inputs along a longitudinal path with varying additive concentrations, allowing for precise control and strategic addition of additives at different stages, enabling the production of granules with specific core and outer layer compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the full amount of additive is introduced in the fresh urea solution prior to entering the fluidized bed, then the additive concentration is uniform along the entire bed, but the additive content in the final product cannot be determined accurately and the concentration is relatively high generating environmental concerns
Solution Approach 1:
The urea solution feed is segmented into multiple separate feeds distributed along the longitudinal growth path of the fluidized bed. Each feed can have different additive concentrations, allowing precise control of additive distribution throughout the granulation process and in different zones of the final granules.
Solution Approach 2:
Different additive concentrations are applied locally at different positions along the granulation path. The additive concentration in each urea feed can be optimized for the specific zone where it is applied, enabling lower overall additive content while achieving the desired stabilizing effect in the outer layers of granules.
2Manufacturing precision
If multiple urea inputs with non-uniform additive concentrations are used, then the additive distribution can be precisely controlled, but the device complexity increases
Solution Approach 1:
The fluidized bed granulator is designed to perform multiple functions: it processes urea solution feeds with varying compositions, accommodates different additive concentrations in different zones, and produces granules with controlled additive distribution. This multi-functionality is achieved through the flexible feed distribution system.
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 allows for accurate control of additive distribution, reducing the amount of additive needed, improving granule stabilization and storage properties, and enabling the production of granules with desired compositions, such as lower formaldehyde content for environmental benefits.
Implementation Method 1
Fluidization is usually achieved with air
Implementation Method 2
fine droplets of a urea solution with a high concentration, usually 96% or greater, are sprayed onto particles of a fluidized bed
Data Source
AI summary
A process for preparation of a granular urea product by granulating a urea solution in a fluidized bed, where the granulation process takes place along a substantially longitudinal growth path, from a granulation starting end (1S) to a product discharge end (1E) of said fluidized bed, and said urea solution enters the fluidized bed by means of several urea inputs (2A, 2B, 2C) taken from a main urea feed (2), where an additive (6) is mixed with said urea solution said additive has a non-uniform concentration in said urea inputs, so that at least two of said urea inputs have a different concentration of additive.