Layer-wise Agglomerated Urea Granules for Controlled Release
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Solution Overview
Problem
Conventional urea fertilizers suffer from high nitrogen loss due to leaching, leading to economic and environmental issues, and existing slow-release fertilizers are expensive and limited in use, necessitating a more environmentally friendly and economically feasible controlled release solution.
Innovation Solution
A layer-wise agglomerated controlled release granular urea composition comprising a core with a water-soluble plant nutrient and a binding material, coated with a hydrogel layer having higher closed porosity, which extends the nutrient release time and matches crop demand curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional urea fertilizers are used, then high nitrogen content (up to 46%) and low price are achieved, but around 70% of applied urea is lost to leaching in regions with high precipitation
Solution Approach 1:
The fertilizer granule is divided into two distinct layers: an inner core layer containing water-soluble plant nutrients and an outer coating layer comprising hydrogel materials with higher closed porosity. This segmentation allows the core to provide rapid nutrient release while the outer layer controls leaching, resolving the contradiction between preventing nitrogen loss and maintaining manufacturing simplicity.
Solution Approach 2:
The invention uses composite material structure combining different materials with complementary properties: the inner core uses water-soluble nutrients for rapid dissolution, while the outer coating uses hydrogel materials with specific porosity characteristics to control water penetration and nutrient release. This composite approach prevents nitrogen loss while keeping the manufacturing process compatible with conventional fertilizer production.
2Duration of action of moving object
If coating material is added to fertilizer granules to extend release time, then dissolution behavior is improved and nutrient use efficiency increases, but the price becomes high limiting use to developed countries
Solution Approach 1:
The outer coating layer is designed with higher closed porosity compared to the inner core, creating a controlled porous structure that regulates water penetration and nutrient release rate. This porous hydrogel structure extends the release time of nutrients while using cost-effective materials and manufacturing methods suitable for developing countries.
Solution Approach 2:
The invention controls the closed porosity parameter of the outer coating layer to be higher than that of the inner core, creating an optimized gradient structure. This parameter optimization extends nutrient release duration while maintaining cost-effectiveness by using simple agglomeration processes rather than expensive coating technologies.
3Duration of action of moving object
If biodegradable materials such as starch and hydrogel are added to urea granules to extend release time, then slow-release performance is achieved, but the structure becomes more complex
Solution Approach 1:
The granule is segmented into two functional layers with distinct porosity characteristics, where the inner core provides rapid nutrient release and the outer porous coating controls the release rate. This simple two-layer segmentation achieves extended release time without requiring complex multi-layer structures or sophisticated manufacturing equipment.
Solution Approach 2:
The outer coating layer utilizes porous hydrogel materials with controlled closed porosity to regulate water and nutrient transport. This porous structure achieves the desired release time extension while maintaining a simple granule architecture that is easy to manufacture using conventional agglomeration processes.
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 solution provides a cost-effective, environmentally friendly fertilizer with a controlled nutrient release pattern that aligns with crop needs, reducing nitrogen loss and environmental pollution while improving nutrient use efficiency.
Implementation Method 1
the closed porosity of the coating layer is higher than the closed porosity of the core
Implementation Method 2
a coating layer comprising the water-soluble plant nutrient and a hydrogel
Implementation Method 3
a core comprising a water-soluble plant nutrient and a binding material to bind the water-soluble plant nutrient
Data Source
AI summary
The present disclosure generally relates to layer-wise agglomerated controlled release granular urea composition and methods of making and using the layer-wise agglomerated controlled release granular urea composition. In a particular composition, the water-soluble plant nutrient comprises urea, the binding material for the core comprises corn starch, the hydrogel for the coating layer comprises corn starch hydrogel, the core has a thickness of 2.5-3.5 mm and a closed porosity of 0.05-3%, and the coating layer has a thickness of 1.35-1.5 mm and a closed porosity of 0.1-5%.