ODDA Process Off-Gas Sand Formation Control
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Solution Overview
Problem
The ODDA process for mineral fertilizer production faces significant challenges with sand formation in off-gas piping, leading to clogging, maintenance issues, and safety hazards, with existing solutions requiring additional devices like fluorine precipitation vessels or absorption towers, which are not cost-effective or practical for high-volume production.
Innovation Solution
Introducing a water jet in the off-gas piping near the acidulation vessels to control or eliminate sand formation, utilizing chemical reactions to prevent SiF4 from converting back to SiO2, thereby reducing or eliminating sand deposition without the need for additional equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ODDA process is used for high-volume fertilizer production, then productivity is improved, but sand formation in off-gas piping occurs leading to clogging and maintenance issues
Solution Approach 1:
A water spray system is installed in the off-gas piping to pre-moisten the gas stream before sand can form and deposit. This preliminary action of adding water prevents the chemical reactions that lead to sand formation, thereby maintaining piping reliability during high-volume production without requiring shutdowns for maintenance
Solution Approach 2:
The invention converts the harmful sand formation process into a beneficial outcome by using water spray to promote the formation of soluble calcium fluoride instead of insoluble sand. The water reacts with silicon tetrafluoride and hydrofluoric acid to form calcium fluoride that remains in solution or forms removable deposits, transforming the clogging problem into a manageable byproduct
2Object-affected harmful factors
If additional devices like fluorine precipitation vessels or absorption towers are installed, then sand formation is reduced, but device complexity and cost increase
Solution Approach 1:
The water spray system utilizes the existing off-gas flow and simple spray nozzles to self-regulate sand formation. The system requires no complex control mechanisms, additional chemical dosing equipment, or sophisticated monitoring systems - just water introduced at strategic points in the piping where it automatically reacts to prevent sand deposition
Solution Approach 2:
The invention uses hydraulic principles by introducing water spray into the gas flow to alter the chemical environment. The water creates a humidified zone that promotes favorable chemical reactions, using fluid dynamics rather than mechanical separation devices or complex absorption towers
3Ease of operation
If sand formation is not controlled, then process operation is simplified, but safety hazards and material damage occur
Solution Approach 1:
The water spray system is positioned upstream in the off-gas piping to prevent sand formation before it can cause hazards. By acting preliminarily, the system eliminates the need for complex safety systems, emergency shutdown procedures, or extensive maintenance protocols, keeping operation simple while ensuring safety
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
This method significantly reduces sand formation in the off-gas piping by at least 90%, preferably 95%, and up to 99%, effectively preventing clogging and associated maintenance and safety concerns, while maintaining the efficiency of the ODDA process without additional process steps or devices.
Implementation Method 1
The water reacts with silicon tetrafluoride and hydrofluoric acid to form soluble calcium fluoride instead of sand
Implementation Method 2
Hydrofluoric acid obtained according to chemical equation 1a reacts with reactive SiO2 to form SiF4 and water according to chemical equation 1b
Implementation Method 3
The SiF4 obtained according to chemical equation 1b reacts with HF to H2SiF6 according to chemical equation 1c
Data Source
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AI summary
The present invention is directed at an ODDA process with reduced sand formation in the off-gas piping for fertilizer production. In a preferred embodiment, the improved sand formation is obtained by the addition of water in the off-gas piping.