Separator Vessel Pressure Relief Assembly for Ignition Risk Abatement
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Solution Overview
Problem
High-pressure polymerization plants face risks of ignition and explosion due to ethylene decomposition, and existing pressure relief systems using rupture discs can cause mechanical damage and uncontrolled releases, failing to adequately manage thrust-induced forces and ignition risks.
Innovation Solution
A pressure relief assembly with a stack of rupture discs of common size, supported by tubular bodies and a spool block, where the tubular bodies extend symmetrically into a base portion, and an ignition abatement system that includes wetting the interior surfaces with water or steam to reduce ignition risks, and accommodates thermal expansion and thrust loads using bellows connectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rupture discs are used for pressure relief, then over-pressure can be relieved, but thrusting action and thrust-induced moments cause mechanical damage to vessel components
Solution Approach 1:
The patent applies asymmetry by offsetting the rupture disc from the centerline of the vessel. This deliberate asymmetric positioning allows the thrusting action to be directed away from the vessel center, reducing the thrust-induced moments on vessel walls and supports. The offset arrangement transforms the symmetric thrust into a controlled asymmetric force that minimizes mechanical damage to components.
Solution Approach 2:
The patent introduces an intermediary structure (the offset rupture disc arrangement with extended exhaust pipe) that mediates between the pressure relief function and the vessel structure. This intermediary configuration absorbs and redirects the thrusting action, preventing direct transmission of damaging forces to the vessel walls and supports.
2Reliability
If gases are released from high pressure separators, then over-pressure is relieved, but the gases may ignite and/or detonate causing damage and injury
Solution Approach 1:
The patent applies the inert atmosphere principle by introducing nitrogen gas into the exhaust pipe to displace and dilute the released ethylene gases. This creates an inert environment that prevents ignition and detonation of the decomposing ethylene, thereby eliminating the harmful ignition risk while maintaining effective pressure relief.
Solution Approach 2:
The patent converts the harmful effect of released ethylene gases (ignition risk) into a benefit by using nitrogen injection to create a protective inert atmosphere. The harmful decomposing gases are transformed from a danger into a controlled release scenario where the nitrogen acts as a protective medium that prevents catastrophic ignition while allowing pressure relief to 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
The solution effectively reduces the risk of ignition and explosion, minimizes mechanical damage from thrust-induced forces, and provides efficient pressure relief in high-pressure vessels by symmetrically distributing pressure relief and using aqueous or steam flows to abate ignition risks.
Implementation Method 1
abating risk of ignition during a relief of an over-pressurized gas from the vessel through the stack by at least one of: (i) wetting an interior surface portion of the stack and (ii) introducing a flow of nitrogen through the stack
Implementation Method 2
introducing a flow of nitrogen through the stack
Data Source
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AI summary
A method and pressure relief assembly for relieving a condition of over-pressure in a vessel are provided. In addition, a separator vessel suitable for operation in a process for polymerizing one or more olefins is provided.