Microchannel Reactor Cooling Surface for Selective Chlorination
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Solution Overview
Problem
Existing chlorination reactions for producing 2-methyl-3-chloroallyl in tubular reactors face issues with temperature control, leading to side reactions, low selectivity, and coking problems due to the lack of a cooling surface, resulting in inefficient production and safety risks.
Innovation Solution
A microchannel reactor with a cooling surface and a high heat exchange area per unit volume is used, where isobutylene and chlorine gas are introduced through small diameter inlet tubes connected in a tee or U-shape, allowing for precise temperature control and efficient mixing, reducing reaction time and maintaining a constant temperature to minimize side reactions and coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a tubular reactor with cooling jacket is used, then the reaction can be carried out at controlled temperature, but the heat exchange area per unit volume is small leading to temperature distribution and local high temperatures
Solution Approach 1:
The reactor is divided into multiple segments with cooling surfaces distributed throughout the reaction path. The reaction tube is segmented into sections, each with its own cooling surface, allowing distributed heat removal rather than concentrated cooling at the ends, thus eliminating temperature distribution issues while maintaining adequate heat exchange area.
Solution Approach 2:
The cooling surface is extended into the reaction path dimension by placing cooling surfaces at multiple positions along the length of the reaction tube. This transforms the traditional external cooling jacket into a distributed cooling system where cooling occurs in the longitudinal dimension, dramatically increasing the heat exchange area per unit volume and eliminating local high temperature zones.
2Device complexity
If no cooling surface is provided at the reaction site, then the reactor structure is simple, but temperature cannot be controlled leading to side reactions and low selectivity
Solution Approach 1:
The reaction tube and cooling surface are merged into an integrated structure where the cooling surface is formed as part of the reaction tube wall system. This integration allows temperature control to be built into the reaction path itself without adding separate complex cooling systems, maintaining structural simplicity while achieving effective temperature control to prevent side reactions.
3Device complexity
If traditional nozzles or spray heads are used for reactant introduction, then the injection system is simple, but they may be blocked due to excessive chlorination and coking
Solution Approach 1:
The traditional nozzle/spray head components are completely removed from the system. Instead of using separate injection devices that are prone to coking and blocking, the reactants are introduced directly through the reaction tube inlet, eliminating the vulnerable nozzle components and their associated reliability issues while maintaining simple system architecture.
4Temperature
If chlorine gas is injected at multiple positions to solve temperature fluctuations, then temperature control is improved, but the flow rate must reach 150-260 m/s and selectivity is limited to 86.5%
Solution Approach 1:
Cooling surfaces are strategically positioned at specific locations along the reaction tube where temperature control is most critical. Rather than uniform cooling throughout, cooling surfaces are placed locally at positions where exothermic reactions generate the most heat, providing targeted temperature control that maintains high selectivity while managing temperature fluctuations effectively.
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 microchannel reactor design achieves high selectivity and stability in the chlorination reaction, reducing side reactions and coking, while maintaining a constant reaction temperature, thereby improving the efficiency and safety of the process.
Implementation Method 1
the cooling surface of the synthesis reactor has a heat exchange area of 8000 ̃20000 m2/m3 based on the actual reaction volume
Implementation Method 2
removes the reaction heat in such a manner that chlorinated reactants circulate to be in direct contact with a reaction gas for cooling
Implementation Method 3
performing a chlorination reaction in a synthesis reactor with a cooling surface, where isobutylene and chlorine gas are introduced
Data Source
AI summary
The present invention relates to a synthesis method and synthesis reactor of high-selectivity 2-methylallyl chloride by taking isobutylene and chlorine gas as raw materials and performing a gas-phase chlorination reaction in a microchannel reactor with a cooling surface. The isobutylene and the chlorine gas are reacted in a T-shaped microchannel reactor, and the mixing speed is extremely fast. Meanwhile, the huge heat exchange area per unit volume can ensure that the reaction proceeds stably at a substantially constant temperature and has good controllability. Therefore, side reactions caused by excessive local temperature can be effectively suppressed, the reaction selectivity is high, and no coking phenomenon occurs.