Urea Prill Granulation for Mechanical Strength
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Solution Overview
Problem
Current granulation technologies for producing solid urea have high investment costs and are inflexible, making them unsuitable for capacity increases, while prilling technology produces low-quality prills that are not ideal for storage due to poor mechanical strength and size limitations.
Innovation Solution
A method involving a two-stage process where prills from a prilling stage are separated by diameter and the larger prills are used as seeds in a granulation stage to produce granules with improved mechanical strength and size, allowing for high-quality solid urea production with lower investment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional granulation technology is used to produce high-quality granules, then product mechanical strength and storage suitability are improved, but investment costs and device complexity increase significantly
Solution Approach 1:
The invention segments the granulation process into two distinct stages: a prilling stage that produces initial prills, and a granulation stage that converts prills to granules. This segmentation allows each stage to be optimized independently, with the prilling stage using simple, low-cost equipment and the granulation stage focusing only on the transformation of prills to granules, thereby reducing overall device complexity while maintaining product quality
Solution Approach 2:
The invention introduces prills as an intermediary product between the melt and final granules. The prilling stage produces prills that serve as seeds for the granulation stage, allowing the system to achieve granule quality without requiring complex direct granulation equipment, thus reducing investment costs and device complexity
2Device complexity
If prilling technology is used to reduce investment costs, then device complexity and investment costs are reduced, but product quality and mechanical strength deteriorate
Solution Approach 1:
The invention ensures continuity of useful action by feeding prills directly from the prilling stage to the granulation stage without interruption. This continuous process ensures that all prills are converted to granules, maximizing the mechanical strength improvement while maintaining simple, low-cost prilling equipment
Solution Approach 2:
The invention changes the physical parameters of the product during processing: prills produced in the first stage have specific size and structural characteristics that are optimized as input for the granulation stage. The granulation process transforms these prills into granules with improved mechanical strength by controlling parameters such as particle size, density, and crystal structure
3Device complexity
If existing prilling towers are used to maintain infrastructure investment, then investment costs are reduced, but production capacity and product quality are limited
Solution Approach 1:
The invention makes the prilling tower multi-functional by using it not only for direct prilling but also as the first stage of a combined prilling-granulation process. This allows the existing infrastructure to serve dual purposes: producing prills that can be directly stored or fed to the granulation stage for enhanced product quality and increased production capacity
Solution Approach 2:
The invention adds a temporal and process dimension to the existing prilling tower by introducing a sequential two-stage process. The prilling tower operates in the first dimension (producing prills), and the granulation stage adds a second dimension (converting prills to granules), thereby increasing overall production capacity and product quality without requiring complete replacement of existing infrastructure
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 method enhances the mechanical strength and storage suitability of urea products, achieving granule quality equivalent to conventional granulation while utilizing existing prilling towers, and increases production capacity with reduced costs.
Implementation Method 1
a method for solidifying (shaping) a chemical product in melt form
Data Source
AI summary
Method for solidifying a chemical product (10) which is in melt form, comprising the following steps: subjecting a first stream (10a) of said chemical product to a prilling stage, with production of prills (12) of varying diameter; feeding said prills (12) to a screening device, which separates them according to their diameter into at least a first fraction (13) and a second fraction (14), the average diameter of the prills of said first fraction (13) being smaller than the average diameter of the prills of said second fraction (14); subjecting a second stream (10b) of said chemical product and the first fraction (13) of prills to a granulation stage, with the production of granules (16).