Ammonium Sulfate Nitrate Granulation for 2:1 Salt Conversion
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Solution Overview
Problem
Existing methods for producing ammonium sulfate nitrate (ASN) fertilizers often result in a mixture of 2:1 and 3:1 double salts, with the 3:1 double salt being more stable, but lacking control over water content, which affects the stability and safety of the final product.
Innovation Solution
A method is developed to produce solid ammonium sulfate nitrate primarily as the 2:1 double salt by controlling the water content between 0.4 and 1.5 wt.% through precise temperature and moisture management in the granulation process, using a granulation bed at 90 °C to 120 °C and supplemental ammonia to facilitate conversion, and further drying to achieve the desired moisture level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional granulation methods are used to produce ASN fertilizer, then production is efficient and continuous, but the product contains a mixture of 2:1 and 3:1 double salts with uncontrolled water content
Solution Approach 1:
The patent applies parameter changes by precisely controlling the water content to 0.4-1.5 wt.% and maintaining the granulation bed temperature between 90-120°C. These specific parameter ranges enable the conversion of 3:1 double salt to 2:1 double salt while achieving the desired product composition and stability.
Solution Approach 2:
The patent employs preliminary action by adding supplemental ammonia to the granulation bed before the melt slurry is applied. This preliminary addition of ammonia creates the necessary chemical environment to facilitate the conversion of 3:1 double salt to 2:1 double salt during the granulation process.
2Reliability
If water content is not controlled in ASN production, then the process is simpler, but the product has increased moisture sensitivity and safety hazards
Solution Approach 1:
The patent achieves improved reliability by changing the water content parameter to a specific range (0.4-1.5 wt.%). This parameter control eliminates moisture sensitivity and safety hazards associated with uncontrolled water content, while the granulation process itself handles the moisture management.
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting the water content during granulation to maintain it within the 0.4-1.5 wt.% range. This feedback mechanism ensures consistent product stability and safety while automating the moisture control aspect of manufacturing.
3Object-affected harmful factors
If 3:1 double salt is the dominant form in ASN fertilizer, then the product is more stable, but it retains detonation hazards and moisture sensitivity
Solution Approach 1:
The patent changes the chemical composition parameters by controlling water content at 0.4-1.5 wt.% and temperature at 90-120°C during granulation. These parameter changes drive the conversion of 3:1 double salt to 2:1 double salt, eliminating detonation hazards and moisture sensitivity.
Solution Approach 2:
The patent uses supplemental ammonia as an intermediary substance added to the granulation bed. This ammonia mediator facilitates the chemical conversion of 3:1 double salt to 2:1 double salt by providing the necessary nitrogen environment for the transformation reaction.
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 maximizes the presence of the 2:1 double salt, enhancing stability and safety by reducing detonation hazards, moisture sensitivity, and classification as a non-hazardous material, while maintaining structural integrity and achieving efficient conversion from 3:1 to 2:1 double salt.
Implementation Method 1
the melt slurry is solidified in the granulation bed of the granulation device to form ammonium sulfate nitrate granules
Implementation Method 2
The solid mixture is conveyed to a drying device and is at least partially dried in the drying device
Data Source
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AI summary
Ammonium sulfate nitrate double salts may be produced using a process that result in complete or nearly complete conversion to the 2:1 double salt. In some embodiments, the disclosure pertains to methods of controlling moisture content during the production process.