Hydrogen Fluoride Production via Controlled Acid Feed
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Solution Overview
Problem
Conventional methods for producing hydrogen fluoride using calcium fluoride and sulfuric acid result in the formation of pasty states, leading to corrosion and energy inefficiencies due to the high corrosivity of sulfuric acid and the adhesion of reaction mixtures to reactor surfaces, which reduces heat transfer efficiency and requires higher energy input.
Innovation Solution
A method where sulfuric acid is supplied to calcium fluoride particles at a controlled flow rate to maintain a particulate state throughout the reaction process, preventing the formation of pasty states and reducing corrosion by ensuring immediate reaction and consumption of sulfuric acid, thereby improving heat transfer and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sulfuric acid is supplied to calcium fluoride particles at a high concentration or rapid rate, then the reaction rate increases, but the mixture transitions to a pasty state causing corrosion and heat transfer inefficiency
Solution Approach 1:
The patent applies dynamics by continuously adjusting the sulfuric acid supply rate based on the reaction progress and maintaining the mixture in a fluidized state. The acid supply rate is dynamically controlled to match the consumption rate, preventing pasty state formation while maximizing reaction efficiency. This dynamic adjustment resolves the contradiction between high reaction rate and avoiding harmful pasty conditions.
Solution Approach 2:
The patent changes key parameters including sulfuric acid concentration, supply rate, and temperature to maintain optimal reaction conditions. By adjusting these parameters, the system keeps the mixture in a particulate/fluidized state rather than transitioning to a pasty state, thereby achieving high productivity without corrosion or heat transfer inefficiency.
2Productivity
If the reaction mixture is heated to high temperatures to increase reaction rate, then productivity improves, but energy consumption increases and corrosion risk increases
Solution Approach 1:
The patent implements continuous reaction and continuous product removal, preventing the accumulation of reaction byproducts that would otherwise require high temperatures for further reaction. This continuous operation allows the reaction to proceed efficiently at lower temperatures, reducing energy consumption and corrosion while maintaining high productivity.
Solution Approach 2:
The patent performs preliminary mixing and pre-reaction steps that prepare the calcium fluoride and sulfuric acid for optimal reaction conditions before main heating. This preliminary action ensures that when heating occurs, the reaction proceeds efficiently at lower temperatures, reducing overall energy consumption and corrosion risk.
3Quantity of substance
If the reaction proceeds to high conversion rates, then hydrogen fluoride yield increases, but the mixture becomes more viscous and adheres to reactor surfaces
Solution Approach 1:
The patent continuously extracts hydrogen fluoride product from the reaction mixture as it forms. This continuous extraction prevents the mixture from becoming overly viscous and adhering to reactor surfaces, while simultaneously maintaining high conversion rates and hydrogen fluoride yield. The product removal shifts the equilibrium forward, enabling high yield without the harmful effects of high viscosity.
4Quantity of substance
If sulfuric acid is supplied in excess to ensure complete calcium fluoride conversion, then hydrogen fluoride yield increases, but unreacted sulfuric acid accumulates causing increased corrosion
Solution Approach 1:
The patent implements feedback control by monitoring the reaction progress and adjusting the sulfuric acid supply rate accordingly. This feedback mechanism ensures that sulfuric acid is supplied at the exact rate needed for complete calcium fluoride conversion without excess accumulation, thereby achieving high hydrogen fluoride yield while minimizing corrosion from unreacted acid.
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 effectively prevents the occurrence of pasty states, reduces corrosion, and enhances energy efficiency by maintaining a particulate state, allowing for lower reaction temperatures and shorter reaction times, thus reducing energy costs and apparatus wear.
Implementation Method 1
reacting calcium fluoride particles with sulfuric acid... CaF2+2H2SO4→Ca(HSO4)2+2HF... Ca(HSO4)2→CaSO4+H2SO4... CaF2+H2SO4→CaSO4+2HF
Implementation Method 2
The reaction mixture is heated to an increased temperature in the rotary kiln 5 while the reaction mixture rolls and advances... The rotary kiln 5 is heated by flowing hot air at about 500° C. through a jacket.
Data Source
AI summary
The present invention provides a novel method for producing hydrogen fluoride which can suppress the occurrence of the pasty state over the whole process of producing hydrogen fluoride, reduce the problem of corrosion caused by sulfuric acid, and improve energy efficiency of the process. A method for producing hydrogen fluoride by reacting calcium fluoride and sulfuric acid comprises: (a) mixing and reacting calcium fluoride and sulfuric acid such that a mixture comprising calcium fluoride particles and sulfuric acid substantially maintains a form of particulate to obtain hydrogen fluoride while supplying sulfuric acid to the calcium fluoride particles at a flow rate of 0.002 to 1 mol/min relative to 1 mol of calcium fluoride to such an amount that a molar ratio of sulfuric acid/calcium fluoride is 0.9 to 1.1.