Dry Gas Seal Leak Recovery by Ejector Pressurization
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Solution Overview
Problem
The environmental impact of natural gas extraction and transportation is significant due to methane leaks from dry gas seals in turbomachines, which contribute to climate change and waste of valuable feedstock.
Innovation Solution
A system and method for recovering seal leak gas from dry gas seals in turbomachines using an ejector to increase the pressure of the recovered gas, allowing it to be reused as seal gas or further treated, with a leak discharge control valve to manage excess gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If seal leak gas is recovered and pressurized using an ejector, then environmental emissions are reduced and gas reuse is enabled, but system complexity increases due to additional components
Solution Approach 1:
An ejector is introduced as an intermediary device to transfer and pressurize seal leak gas from low pressure to high pressure, enabling the gas to be reused as seal gas or discharged to atmosphere. The ejector uses motive gas to create a vacuum that draws in seal leak gas and delivers it at elevated pressure, thereby reducing environmental emissions without requiring a complex mechanical compressor system
Solution Approach 2:
The system employs pneumatic principles through the ejector, which uses compressed motive gas to create a vacuum effect and transport seal leak gas. This pneumatic approach avoids mechanical moving parts and complex control systems while achieving effective gas recovery and pressurization, thus reducing emissions with minimal added complexity
2Reliability
If a leak discharge control valve is added to manage excess gas flow, then operational availability increases, but device complexity increases
Solution Approach 1:
A leak discharge control valve is incorporated to dynamically adjust the flow of seal leak gas based on system conditions. The valve enables the system to adapt to varying operational requirements by controlling the discharge of excess gas, thereby maintaining operational availability and preventing over-pressurization while adding only a single adjustable component
Solution Approach 2:
The control valve allows for parameter changes in gas flow rate and pressure by adjusting its opening position. This enables the system to respond to changing operational conditions and maintain optimal performance, improving reliability while adding minimal complexity through a single valve component
3Device complexity
If seal leak gas is discharged to atmosphere or flare, then system simplicity is maintained, but valuable feedstock is wasted and environmental impact increases
Solution Approach 1:
Instead of discarding seal leak gas to atmosphere or flare, the system recovers the gas using an ejector to pressurize it for reuse as seal gas or for other beneficial purposes. This recovery approach prevents waste of valuable natural gas feedstock and reduces environmental impact while adding only moderate system complexity
Solution Approach 2:
The system converts the harmful effect of seal leak gas discharge into a beneficial resource by recovering and pressurizing the gas for reuse. The previously wasted seal leak gas becomes a valuable resource that can be recycled back into the system or used elsewhere, transforming an environmental problem into an operational benefit
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 system effectively recovers and pressurizes seal leak gas, reducing environmental emissions and increasing the operational availability of turbomachines by allowing continued operation even when the ejector is non-operational.
Implementation Method 1
an ejector having: a motive gas inlet at a motive gas inlet pressure, a seal leak gas inlet at a seal leak gas pressure, and a mixed gas outlet at a mixed gas outlet pressure higher than the seal leak gas pressure
Data Source
AI summary
The system comprises a rotary turbomachine, including dry gas seals. A seal leak gas collecting line fluidly connects the at dry gas seals to the seal leak gas inlet of the ejector. A seal leak gas discharging line fluidly couples the dry gas seals with a seal leak gas discharge at a discharge pressure, lower than the seal leak gas pressure. A leak discharge control valve along the seal leak gas discharging line is adapted to divert at least part of the seal leak gas in the seal leak gas discharging line. Also, a method for recovering seal gas leaking from a dry gas seal arrangement is disclosed.