UCS Fertilizer Granules With Staged Moisture-Controlled Granulation
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Solution Overview
Problem
Existing methods for producing calcium sulfate urea (UCS) adduct fertilizers face challenges such as high moisture content in slurries, which hinder UCS adduct formation and practicality of direct granulation, leading to difficulties in producing stable and high-nitrogen content fertilizers.
Innovation Solution
A multi-step process involving the conversion of urea and calcium sulfate to a UCS adduct, followed by optional storage and granulation, allowing for the production of stable UCS fertilizer granules with controlled moisture levels and high nitrogen content, without the need for solid-liquid separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high moisture content slurry is used to produce UCS adduct, then the slurry is easier to pump and handle, but the UCS adduct formation is hindered and direct granulation becomes impractical
Solution Approach 1:
The production process is divided into two separate stages: (1) UCS adduct formation in a reaction vessel with controlled low moisture slurry, and (2) granulation in a separate granulator. This segmentation allows each stage to operate under optimal conditions - low moisture for adduct formation and appropriate moisture for granulation - resolving the contradiction between pumpability and adduct formation.
Solution Approach 2:
The UCS adduct is formed preliminarily in the reaction vessel before granulation occurs. By pre-forming the adduct with controlled moisture content, the subsequent granulation step can proceed effectively without the pumpability requirements constraining the adduct formation process.
2Ease of manufacture
If moisture is reduced to less than 20% in the slurry, then UCS adduct formation is improved, but the slurry becomes difficult or impractical to pump
Solution Approach 1:
The process separates slurry preparation from adduct formation by using a two-stage system. The slurry is prepared with sufficient moisture for pumpability, then transferred to a reaction vessel where controlled conditions (heating, stirring) promote adduct formation. This eliminates the need to maintain low moisture throughout the entire process.
Solution Approach 2:
The moisture content parameter is optimized differently at different stages: higher moisture during slurry preparation and transfer for pumpability, then reduced to optimal levels during the reaction phase for maximum adduct formation. Temperature and stirring parameters are also adjusted to facilitate adduct formation from the prepared slurry.
3Quantity of substance
If urea is used in fertilizer blends, then nitrogen content is increased, but urea reacts with other components producing water that liquefies granules and causes clumping
Solution Approach 1:
The invention creates a composite UCS adduct material where urea is chemically bound to calcium sulfate in a specific stoichiometric ratio (4:1). This composite structure prevents the free urea from reacting with other fertilizer components, thereby maintaining granule stability while preserving high nitrogen content. The adduct itself becomes a stable composite that can be blended with other fertilizers without the clumping problems of pure urea.
Solution Approach 2:
Calcium sulfate acts as an intermediary that binds with urea to form the UCS adduct. This intermediary compound serves as a stable carrier for nitrogen, preventing direct interaction between urea and other fertilizer components that would otherwise cause unwanted reactions and granule degradation.
4Quantity of substance
If urea reacts with other fertilizer components, then nitrogen availability increases, but water production liquefies solid granules and increases reaction rate causing product loss
Solution Approach 1:
The invention converts the potentially harmful reaction between urea and other components into a beneficial process by pre-forming the UCS adduct. The controlled reaction between urea and calcium sulfate produces the desired adduct structure, and any water produced is managed through the drying and granulation process. This transforms what would be a harmful side reaction into the primary formation mechanism for the stable fertilizer product.
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
The process enables the production of high-quality UCS fertilizer granules with controlled moisture and nitrogen content, overcoming the limitations of current methods by ensuring stability and practicality in production.
Implementation Method 1
conversion of urea and calcium sulfate to a UCS adduct
Implementation Method 2
removing at least a portion of water from the aqueous slurry
Data Source
AI summary
A urea calcium sulfate (UCS) fertilizer granule and methods for making and using the same are disclosed. The granule can include a urea-calcium sulfate (UCS) adduct. The method of making can include producing a partially dried material comprising UCS adduct and forming the UCS fertilizer granules by either one or both of feeding the partially dried material into a separate vessel for granulation or granulating after storage of the partially dried material.