Benzene Alkylation Catalyst Regeneration via Heated n-Hexane Washing
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Solution Overview
Problem
Conventional methods for regenerating solid acid catalysts in benzene alkylation processes, such as hot benzene washing and carbon burning, are inefficient in removing residues and cause permanent damage to the catalyst, leading to reduced catalytic activity and short catalyst lifetime.
Innovation Solution
A regeneration method involving purging the catalyst with a gas, injecting heated n-hexane to wash out benzene alkylation reaction residues, and then cooling, which enhances solubility and avoids structural damage, using a process that includes specific pressure, temperature, and duration parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot benzene washing regeneration method is used, then the catalyst can be regenerated, but it cannot remove all residues on the surface and in the channels of the catalyst, resulting in gradual decrease in single pass lifetime
Solution Approach 1:
The patent changes the chemical parameter of the washing solvent from benzene to n-hexane. This parameter change fundamentally improves the solubility of reaction residues (isomerization and cracking products) in the washing liquid, enabling complete removal of residues from catalyst surface and channels, thereby resolving the contradiction between regeneration effectiveness and catalyst lifetime
Solution Approach 2:
The patent uses n-hexane as a substitute solvent that copies the washing function of benzene but with superior solubility properties for the specific residues produced in this reaction system, achieving better regeneration results without the limitations of benzene
2Reliability
If carbon burning regeneration method is used, then residues can be removed by burning, but the channel structure of the catalyst will be permanently damaged, resulting in permanent decrease in catalytic activity and decrease in long period lifetime
Solution Approach 1:
Instead of using high temperature burning (which causes damage), the patent converts the harmful thermal degradation into a beneficial solvent washing process. The n-hexane solvent selectively dissolves and removes the harmful residues without causing damage to the catalyst structure, achieving residue removal while preserving catalyst integrity and extending long-term lifetime
Solution Approach 2:
The patent replaces the mechanical/thermal destruction method (carbon burning at 650°C) with a chemical dissolution method (n-hexane washing). This substitution eliminates the need for high temperature that causes channel structure damage, while still achieving effective residue removal through solubility differences
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 improves the regeneration effect, extends the catalyst's lifetime, and maintains high catalytic activity, with the catalyst being able to be regenerated repeatedly and maintaining 99% or more initial conversion efficiency.
Implementation Method 1
continuously injecting n-hexane at a feed port of the reactor and heating the n-hexane to wash the solid acid catalyst, and discharging the n-hexane entraining benzene alkylation reaction residues
Implementation Method 2
heating the n-hexane to wash the solid acid catalyst
Data Source
AI summary
A regeneration method for a benzene alkylation solid acid catalyst, comprising: purging the solid acid catalyst in a reactor with a gas; continuously injecting n-hexane at a feed port of the reactor and heating the n-hexane to wash the solid acid catalyst, and discharging the n-hexane entraining benzene alkylation reaction residues from a discharge port of the reactor; and stopping injecting n-hexane, cleaning off a liquid in the reactor by purging with the gas, and cooling the reactor. In the regeneration method of the present disclosure, the regeneration liquid used is n-hexane, which can increase the solubility of the residues in channels and enhance the regeneration effect. Meanwhile, permanent damage to the channel structure of the catalyst caused by carbon burning regeneration can be avoided, thereby prolonging the lifetime of the catalyst.