Fixed Bed Reactor Solid Acid Inhibitor Suppression
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Solution Overview
Problem
Fixed bed reactors for gas-phase catalytic oxidation face challenges with catalyst inhibitor deposition, leading to increased pressure loss and reduced yield, requiring periodic catalyst restoration and disrupting continuous operation.
Innovation Solution
Incorporating a solid acid with specific acid strength (-5.6 ≤ H0 ≤ 1.5) into the reactor, either as a layer or mixed with the catalyst, using complex oxides containing elements like aluminum, silicon, or zirconium, to suppress catalyst inhibitor deposition and maintain high yield during long-term continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catalyst restoration is performed by taking out the catalyst from the reaction tube, then catalyst performance can be restored, but working time for taking out and re-filling the catalyst is lost and continuous operation is disrupted
Solution Approach 1:
The harmful component (catalyst inhibitor) is extracted from the catalyst surface through selective adsorption by the solid acid, allowing the catalyst to be restored in-situ without removal from the reaction tube, thus maintaining continuous operation while restoring catalyst performance
Solution Approach 2:
A solid acid is introduced as an intermediary substance that selectively adsorbs catalyst inhibitors from the catalyst surface, enabling indirect restoration of catalyst activity without direct contact or removal of the catalyst itself
2Reliability
If catalyst restoration is performed by heat treatment with mixed gas inside the reaction tube, then catalyst can be restored without taking out, but the reaction must be stopped every time
Solution Approach 1:
The solid acid is designed to continuously adsorb catalyst inhibitors during the reaction process, maintaining catalyst activity without interruption and enabling uninterrupted continuous operation, thus preserving both productivity and reliability
3Productivity
If catalyst inhibitor deposition is not suppressed, then pressure loss increases and yield decreases, but periodic restoration disrupts continuous operation
Solution Approach 1:
The solid acid performs self-service by continuously and automatically adsorbing catalyst inhibitors as they are formed during the reaction, eliminating the need for external intervention or periodic shutdowns, thus maintaining both high yield and continuous operation
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 approach stabilizes continuous operation for extended periods by reducing pressure loss and maintaining high yields of acrolein or acrylic acid production, thereby lowering production costs.
Implementation Method 1
a solid acid...is placed in a gas passage containing a starting material compound and/or a produced compound...to suppress the deposition of the catalyst inhibitor
Implementation Method 2
a reaction tube filled with a gas-phase oxidation catalyst...gas-phase catalytic oxidation of propylene...to produce acrolein or acrylic acid
Implementation Method 3
gas-phase catalytic oxidation...oxidizing propylene to produce mainly acrolein and the second stage for oxidizing acrolein to produce mainly acrylic acid
Data Source
AI summary
A fixed bed reactor including a reaction tube filled with a gas-phase oxidation catalyst, wherein a solid acid, of which acid strength (H0) meets an inequality: -5.6 ≤ H0 ≤ 1.5, is placed in a gas passage containing a starting material compound and/or a produced compound; a process for producing acrolein, the process including using the above fixed bed reactor for production of acrolein by gas-phase catalytic oxidation of propylene with molecular oxygen; a process for producing acrylic acid, the process including using the above fixed bed reactor for production of acrolein by gas-phase catalytic oxidation of propylene with molecular oxygen and for subsequent production of acrylic acid by gas-phase catalytic oxidation of the acrolein with molecular oxygen; and a method for suppressing deposition of a catalyst inhibitor in a fixed bed reactor including a reaction tube filled with a gas-phase oxidation catalyst, the method including placing a solid acid, of which acid strength (H0) meets an inequality: -5.6 ≤ H0 ≤ 1.5, in the fixed bed reactor for gas-phase catalytic oxidation.