Reactor Depressurization Valve Layout for High-Pressure Polymerization
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Solution Overview
Problem
High pressure polymerization reactors face challenges in rapid depressurization, particularly in larger systems, due to flow reversal and stagnant zones caused by multiple pressure relief valves, leading to overheating and potential failure.
Innovation Solution
Locate a pressure relief valve downstream of the reactor and an additional valve in a cooling zone, ensuring that stagnant zones remain within the cooling zone during depressurization, eliminating flow reversal and maintaining rapid depressurization capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple pressure relief valves are used to achieve rapid depressurization, then the depressurization speed is improved, but flow reversal and stagnant zones are created leading to overheating and potential failure
Solution Approach 1:
The reactor is divided into multiple zones with different functions (reaction zones and cooling zones). Pressure relief valves are strategically positioned at specific locations (downstream of the reactor and in cooling zones) rather than uniformly distributed, segmenting the depressurization function to avoid flow reversal while maintaining rapid pressure reduction capability
Solution Approach 2:
Cooling zones act as intermediary regions that receive stagnant flow during depressurization. By positioning pressure relief valves such that stagnant zones form in cooling zones rather than reaction zones, the harmful thermal effects are isolated to regions designed for heat removal, preventing overheating and reactor failure
2Speed
If pressure relief valve is located at the inlet of the preheater or between the preheater and reactor entry, then rapid depressurization is achieved, but flow reversal creates stagnant zones in the highest temperature area leading to decomposition
Solution Approach 1:
Different locations within the reactor system are assigned different functions based on their thermal characteristics. Cooling zones are specifically designed to accommodate stagnant flow, while reaction zones (including the preheater inlet area) are protected from stagnation. Pressure relief valves are positioned to ensure stagnant zones form only in appropriate cooling regions, not in high-temperature reaction zones where decomposition would occur
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
Achieves rapid depressurization of high pressure polymerization reactors, reducing pressure from 2000 bar to 1000 bar in less than 10 seconds without creating stagnant zones that could lead to overheating or failure.
Implementation Method 1
rapid depressurization of a reactor system... opening a first pressure relief valve located downstream of the reactor... opening a second pressure relief valve located along the reactor in a cooling zone
Data Source
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AI summary
Systems and processes for rapidly depressurizing a reactor system are disclosed. The systems and processes are particularly useful in the high pressure polymerization of ethylene.