Underground Gas Cavern Pressure Relief with Isolation Valves
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Solution Overview
Problem
High-pressure gases stored in underground salt caverns pose safety risks due to excessive pressures exceeding pipeline pressures, and existing pressure control solutions require large and costly vent or flare stacks for pressure relief.
Innovation Solution
A method and apparatus that includes a pressure reducing device, isolation valves, and downstream equipment to monitor and control gas pressure, allowing for reduced size of the vent or flare stack by isolating the flow when pressures exceed certain thresholds, and includes moisture and impurity removal systems to ensure safe pipeline introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure relief valve is used to provide over-pressure protection for the entire underground storage cavern, then safety is improved, but the size and cost of the vent or flare stack must be large enough to handle the entire cavern volume, increasing capital expenditure
Solution Approach 1:
The system divides the pressure relief function into two segments: (1) a pressure control device that normally controls pressure by reducing it to pipeline levels, and (2) a pressure relief valve with isolation valves that provides backup protection. The isolation valves segment the flow path to limit the volume that the pressure relief valve must handle, allowing for a smaller vent or flare stack while maintaining safety for the entire cavern.
2Stress or pressure
If a pressure control device is used to reduce gas pressure before pipeline introduction, then pressure compatibility is improved, but the device becomes a potential failure point that compromises overall safety
Solution Approach 1:
The system implements a backup pressure relief valve positioned downstream of the pressure control device. This backup device acts as a cushion or safety net that will activate if the primary pressure control device fails, preventing over-pressure conditions and maintaining system safety despite the presence of the pressure control device as a potential failure point.
3Reliability
If the vent or flare stack is sized to handle the entire cavern volume, then complete over-pressure protection is achieved, but capital expenditure increases significantly
Solution Approach 1:
The system segments the pressure relief responsibility between the pressure control device (primary) and the pressure relief valve (backup). The isolation valves further segment the flow path to limit the backup relief valve's responsibility to a portion of the cavern volume, enabling a smaller, more cost-effective vent or flare stack while maintaining complete protection through the coordinated operation of both pressure control mechanisms.
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 solution provides enhanced safety and reduced capital expenditure by enabling smaller vent or flare stacks while maintaining operational safety and integrity of the pipeline and downstream equipment.
Implementation Method 1
reducing the pressure of the pressurized gas to form a lower pressure gas
Implementation Method 2
monitoring the pressure of the lower pressure gas
Implementation Method 3
sending a signal to a controller to close a set of isolation valves located upstream of a pressure relief valve
Implementation Method 4
venting at least a portion of the lower pressure gas to a vent or flare stack via a pressure relief valve
Data Source
AI summary
A method and apparatus is provided which will provide over-pressure protection for an underground storage cavern (10) by reducing the pressure of a pressurized gas stream originating from the an underground storage cavern to form a lower pressure gas stream, monitoring (15) the pressure of a lower pressure gas stream and stopping the flow (8) of the lower pressure gas stream to the pipeline should the pressure of the lower pressure gas stream exceed a threshold value.