Turbo-compressor and Ejector for Natural Gas Pressure Boost
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Solution Overview
Problem
Existing methods for increasing low-pressure gas streams in oil and gas production, such as ejectors, are inefficient and costly, particularly when mechanical compressors are not economically viable for small pressure increments, leading to energy wastage and high operational expenses.
Innovation Solution
A method utilizing a turbo-compressor unit with mechanically connected turbine and compressor impellers, where a high-pressure drive fluid is used to power the turbine, and the output is fed to an ejector to boost the low-pressure gas stream before it enters the compressor, optimizing energy use and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a mechanical compressor is used to increase gas pressure, then the pressure increase is reliable and controllable, but the installation and operational costs are too high
Solution Approach 1:
The patent replaces the mechanical compressor system with a pneumatic compression system using ejectors. High-pressure gas from the production stream provides the driving force for compression through pneumatic principles rather than mechanical motors and compressors, eliminating the need for expensive mechanical compression equipment while achieving the required pressure increase for gas lifting.
Solution Approach 2:
The system uses the high-pressure gas already present in the production stream to power the compression process. The same gas that needs to be utilized for lifting is also used as the energy source to compress additional gas, creating a self-sustaining system that eliminates external power requirements and reduces operational costs.
2Ease of manufacture
If an ejector is used to increase gas pressure, then the installation cost is low, but the energy efficiency is poor with significant energy wastage
Solution Approach 1:
The patent combines multiple ejectors into an integrated compression system where the exhaust from one ejector serves as the driving pressure source for the next ejector in sequence. This merging of functions allows the system to achieve higher overall pressure increases while recovering and reusing the energy in the exhaust streams, significantly improving energy efficiency compared to standalone ejectors.
Solution Approach 2:
Instead of discarding the exhaust gas from ejectors, the system recovers its pressure energy by using it as the driving force for subsequent ejectors. This recovery approach transforms what would be wasted energy into a useful resource, maintaining the simplicity and low cost of ejector technology while dramatically reducing energy losses.
3Adaptability or versatility
If high-pressure gas is used to drive ejectors for compression, then the operational flexibility is good, but the energy efficiency deteriorates due to mixing different pressure streams
Solution Approach 1:
The patent extracts the compression function from the gas mixing process. By using a series of ejectors arranged in sequence, each operating with its own dedicated high-pressure and low-pressure streams, the system achieves the required pressure increase without forcing different pressure streams to mix. This extraction of the compression function maintains operational flexibility while avoiding the energy inefficiencies of stream mixing.
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 approach significantly improves efficiency, reducing energy wastage and operational costs by achieving pressure increments of up to 20 bar with an estimated 85% efficiency, compared to 17% for ejectors, and offering substantial savings in fuel consumption and increased production capacity.
Implementation Method 1
passing a drive fluid at a pressure of 30 to 500 bar through the turbine housing of the turbo-compressor unit
Implementation Method 2
passing the natural gas stream through a compressor housing of a turbo-compressor unit
Implementation Method 3
The output from the turbine side is fed to an ejector to boost the low-pressure gas stream
Data Source
AI summary
A method of raising the pressure of a natural gas stream (9) on an oil or gas producing installation (1) comprises using an existing high pressure gas stream (13) at the installation to drive the turbine (12) of a turbo-compressor unit (10). It is common on oil and gas producing installations to require the pressure of a gas stream to be increased by a small amount, e.g. to allow flare gas to be fed to the production gas train thereby avoiding flaring. This system may replace the current practice of using ejectors for this purpose since ejectors are very inefficient. However, it can be advantageous to feed the output of the turbine side (12) of the turbo-compressor (10) to an ejector which can give a small pre-boost to the low pressure natural gas (9) before it enters the compressor side (11) of the turbo-compressor (10). (FIG. 2).