UV Urea Feed Treatment for Low-Ammonia Fertilizer Granulation
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Solution Overview
Problem
Existing fertilizer production processes face challenges in reducing ammonia emissions during granulation, which require complex and energy-consuming ammonia offgas scrubbers, leading to increased capital and operating costs, and result in unwanted product properties due to ammonium salts formation.
Innovation Solution
A method involving photocatalytic decomposition of ammonia using UV radiation in the urea melt or solution supply line before it enters the granulator, effectively decomposing ammonia to nitrogen and water, eliminating the need for traditional scrubbers and preventing biuret formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If offgas scrubbers are used to remove ammonia emissions, then ammonia emission limits are met, but device complexity and energy consumption increase significantly
Solution Approach 1:
The invention extracts and removes ammonia from the urea melt or concentrated urea solution before granulation using a stripping column. This prevents ammonia from entering the granulator offgas stream, thereby eliminating the need for complex offgas scrubbing apparatus while still meeting emission requirements.
Solution Approach 2:
The invention performs preliminary ammonia removal from the urea melt or concentrated urea solution in a stripping column before the granulation process. By removing ammonia in advance, the subsequent granulation process generates offgas with ammonia concentrations below detection limits, eliminating the need for downstream scrubbing equipment.
2Object-affected harmful factors
If offgas scrubbers are used to remove ammonia, then emission limits are satisfied, but operating costs and energy consumption increase
Solution Approach 1:
The invention extracts and removes ammonia from the urea melt or concentrated urea solution before granulation using a stripping column. This prevents ammonia from entering the granulator offgas stream, thereby eliminating the need for complex offgas scrubbing apparatus while still meeting emission requirements.
Solution Approach 2:
The invention performs preliminary ammonia removal from the urea melt or concentrated urea solution in a stripping column before the granulation process. By removing ammonia in advance, the subsequent granulation process generates offgas with ammonia concentrations below detection limits, eliminating the need for downstream scrubbing equipment.
3Productivity
If ammonia is absorbed in the urea melt during granulation, then granulation process proceeds, but unwanted biuret formation increases
Solution Approach 1:
The invention performs preliminary ammonia removal from the urea melt or concentrated urea solution in a stripping column before the granulation process. By removing ammonia in advance, the subsequent granulation process generates offgas with ammonia concentrations below detection limits, eliminating the need for downstream scrubbing equipment.
Solution Approach 2:
The invention changes the ammonia concentration parameter in the urea melt or concentrated urea solution by using a stripping column to reduce ammonia content to below detection limits. This parameter change prevents biuret formation during granulation while maintaining the granulation process efficiency.
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
Reduces ammonia emissions without additional equipment complexity, lowers energy consumption, and maintains product quality by preventing ammonium salt accumulation, thus optimizing production efficiency and cost-effectiveness.
Implementation Method 1
ammonia is decomposed by UV radiation at least predominantly to nitrogen and water
Implementation Method 2
fluidizing air is blown in from below, causing the particles to be maintained in a fluidized state in the reactor space of the granulator
Data Source
AI summary
A method for producing a fertilizer that comprises urea and/or at least one ammonium compound may involve obtaining ammonia as an impurity in the production process, and photocatalytically decomposing the ammonia by irradiation with UV radiation. Further, an apparatus for producing fertilizer granules that comprise urea and/or at least one ammonium compound may include a plant section having a fertilizer granulator configured to produce the fertilizer granules, a supply line configured to pass a urea melt or a concentrated urea solution to the plant section, a UV lamp arrangement that is proximate the supply line and is configured to irradiate with UV radiation the urea melt or the concentrated urea solution flowing in the supply line.