Catalyst HF Removal via Thermal Desorption

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Solution Overview

Problem

The existing methods for removing catalysts from reactors containing hydrogen fluoride (HF) are unsafe as they fail to completely purge HF, risking exposure to operators due to residual HF absorption on catalysts, which can desorb later.

Innovation Solution

A method involving heating the reactor to at least 80°C and purging with inert gas at a rate of ≥ 10 ml/min per gram of catalyst after the reaction to desorb and discharge HF, ensuring the ambient temperature is higher than the reaction temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the reactor is purged with inert gas to remove HF after reaction, then the HF concentration in the gas phase is reduced, but HF absorbed on the catalyst surface remains and can desorb later causing operator exposure

Engineering Contradiction:
ImproveHF exposure risk to operatorsVSAvoidcompleteness of HF removal
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies preliminary action by performing heat treatment at 80°C or higher before the inert gas purging step. This pre-heating treatment causes HF absorbed on the catalyst surface to desorb in advance, converting it to gas phase HF that can then be effectively removed by the subsequent inert gas purging. This resolves the contradiction by ensuring both gas phase and catalyst-absorbed HF are removed, eliminating operator exposure risk while achieving complete HF removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses heat treatment as an intermediary process between the reaction completion and inert gas purging. This intermediary heat treatment step facilitates the transfer of HF from the catalyst surface to the gas phase, making it accessible to the inert gas for removal. This intermediary action ensures both phases of HF are addressed, resolving the reliability issue while maintaining safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the reactor is disassembled to remove the catalyst, then the catalyst can be replaced to maintain reaction performance, but operators are exposed to residual HF that was not completely purged

Engineering Contradiction:
Improvecatalyst replacement frequencyVSAvoidoperator safety
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs heat treatment at 80°C or higher before disassembly to preliminarily remove HF from the catalyst surface. This preliminary action ensures that when the reactor is disassembled for catalyst replacement, the catalyst has already been detoxified, protecting operators from HF exposure while maintaining regular catalyst replacement schedules for productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts HF from the catalyst surface through heat treatment before catalyst removal. By extracting the harmful substance (HF) from the catalyst in advance, the catalyst can be safely removed and replaced without exposing operators to residual HF, thus maintaining both productivity and safety.

Inventive Principle:
Principle #2Taking out (Extraction)

3Use of energy by moving object

If inert gas purging is performed at low temperature, then energy consumption is reduced, but HF absorbed on the catalyst is not effectively removed

Engineering Contradiction:
Improveenergy consumption for purgingVSAvoidHF removal efficiency
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary heat treatment at 80°C or higher to release HF from the catalyst surface before inert gas purging. This preliminary thermal energy input facilitates subsequent low-temperature purging, as the HF is already in gas phase and doesn't require high energy consumption for desorption during the purging step itself, thus maintaining energy efficiency while ensuring complete HF removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the need for high-energy mechanical or thermal purging systems by using low-temperature heat treatment followed by simple inert gas flow. The thermal energy is applied selectively and minimally (just 80°C or higher), substituting complex high-energy removal systems with a simple thermal-preparation plus gas-flow approach, reducing overall energy consumption while maintaining high HF removal efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 HF concentration in the reactor, minimizing the risk of operator exposure and enabling safe catalyst removal and apparatus disassembly.

Implementation Method 1

heating the inside of the reaction system at a predetermined ambient temperature... heating the reactor to at least 80°C... desorb and discharge HF

Methodology Applied
Scientific EffectDesorption: Desorption

Implementation Method 2

performing heat-treatment so that the ambient temperature of the reactor is ≥ 80°C

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 3

HF is easily absorbed to catalysts... flowing inert gas into the reactor... absorb HF

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 4

flowing inert gas into the reactor at a rate of ≥ 10 ml/min per gram of the catalyst to discharge the hydrogen fluoride

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3238820B1Method for removing catalyst used in reaction
Publication Date: 2020.03.11 DAIKIN INDUSTRIES LTD

AI summary

Provided is a method for easily and safely removing, from a reactor, a catalyst used in a reaction that is performed using hydrogen fluoride in the presence of the catalyst. In a reaction performed in a reactor containing at least hydrogen fluoride and a catalyst, the catalyst is removed through a process comprising a heating step of performing heat-treatment so that the ambient temperature of the reactor is 80°C or more after completion of the reaction, and a purge step of flowing inert gas into the reactor to discharge the hydrogen fluoride to the outside of the reactor after completion of the reaction.