Catalytic Oxychlorination Process for Ethylene Dichloride
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Solution Overview
Problem
Catalysts used in fluidized bed reactors for oxychlorination of ethylenically unsaturated hydrocarbons suffer from stickiness, leading to reduced reaction rates, increased residual HCl, and economic losses due to the need for reactor shutdowns, despite efforts to address this issue with co-precipitation and promoter-based solutions.
Innovation Solution
A process using a copper-based oxychlorination catalyst with a refractory oxide support, impregnated with CuCl2, and optimized O2/2HCl ratio of 0.50 to 0.58, which maintains high activity and prevents stickiness, ensuring high HCl conversion and EDC selectivity while minimizing COx production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If copper-based catalysts are used in fluidized bed reactors for oxychlorination, then high catalytic activity is achieved, but catalyst particles stick together causing fluidization problems and reduced reaction rates
Solution Approach 1:
Magnesium chloride serves as an intermediary substance that forms a protective layer on the catalyst particle surface, preventing direct contact and adhesion between copper-containing catalyst particles, thereby maintaining fluidization stability while preserving catalytic activity
Solution Approach 2:
The catalyst system employs a composite structure combining copper chloride (catalytic component) with magnesium chloride (anti-sticking component) on an alumina support, creating a multi-functional material that simultaneously provides catalytic activity and anti-agglomeration properties
2Productivity
If oxygen feed ratio is increased to reverse sticking, then conversion rate increases and residual HCl decreases, but oxidation to CO and CO2 increases reducing product yield
Solution Approach 1:
Magnesium chloride acts as an intermediary that disrupts the stickiness mechanism at its source, allowing the reaction to proceed at optimal oxygen levels without requiring excessive oxygen supplementation to counteract sticking-related conversion losses
Solution Approach 2:
The magnesium chloride component continuously performs the anti-sticking function during reaction operation, automatically preventing catalyst agglomeration and maintaining stable fluidization and conversion rates without requiring external intervention or oxygen ratio adjustments
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 process achieves HCl conversion of at least 99.4% and EDC selectivity of at least 98.5%, with a critical O2/2HCl ratio below 0.52, preventing stickiness and maintaining reactor efficiency, thus reducing operational costs and product yield loss.
Implementation Method 1
The present invention relates to a process for the catalytic oxychlorination of ethylenically unsaturated hydrocarbons
Implementation Method 2
During the catalytic reaction the copper ions are reduced from Cu(II) to Cu(I), and again oxidized to Cu(II)
Implementation Method 3
Fluid bed reactors use catalysts based on copper salts, preferably CuCl2, on a support. The support has a particle size suitable for good fluidization
Data Source
AI summary
A process is disclosed for the catalytic oxychlorination of an olefin. In the process a feed containing the olefin, O2 and HCl is contacted with an oxychlorination catalyst. The O2/2HCl ratio in the feed is in the range of from 0.50 to 0.58. Catalyst compositions for use in the oxychlorination reaction, in particular the oxychlorination of ethylene, are also disclosed. The catalyst compositions are in the form of particles suitable for use in fluid bed reactors, in particular baffled fluid bed reactors. Preferred catalyst materials comprise from 5.5 wt % to 14 wt % Cu. They may further comprise an earth alkali metal, such as Mg, and/or a rare earth metal. Preferred compositions contain less than 1 wt % of an alkali metal, which preferably is K.