Fuel Gas Conditioning for Compressor Hydrate Prevention
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Solution Overview
Problem
Conventional gas lift compressor systems face limitations in fluid lift rates and are susceptible to hydrocarbon condensation and hydrate formation due to unprocessed feed gas with heavier hydrocarbon molecules, especially in High Pressure Gas Lift (HPGL) applications, where pressures fluctuate and contain produced water, leading to operational issues and increased costs.
Innovation Solution
A specialized gas compressor system with a three-stage compression design and a fuel gas conditioning system that uses scrubbers, heat exchangers, and pressure reducing valves to maintain the gas in the vapor phase, preventing condensation and hydrate formation by controlling pressure and temperature, and utilizing engine coolant as an on-skid heat source to condition the fuel gas for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional gas lift compressor systems use unprocessed feed gas with heavier hydrocarbon molecules, then the system can operate with simpler equipment, but hydrocarbon condensation and hydrate formation occur leading to operational issues
Solution Approach 1:
The system segments the gas processing into multiple stages: a first compressor stage that handles initial compression, followed by a scrubber for liquid removal, then a second compressor stage for further compression. This segmentation allows each component to perform its specific function optimally while preventing condensation and hydrate formation through controlled processing stages.
2Productivity
If High Pressure Gas Lift (HPGL) applications use fluctuating pressures with produced water present, then the system can handle higher production rates, but hydrate formation and operational issues increase
Solution Approach 1:
The system performs preliminary actions by removing produced water through the scrubber before the gas enters the second compression stage. This preliminary removal of liquid water prevents it from combining with hydrocarbons to form hydrates during the high-pressure HPGL operation, thereby maintaining high productivity without hydrate formation issues.
3Device complexity
If the system compresses gas to high pressures without intermediate processing, then the compression process is simpler, but hydrocarbon condensation occurs reducing system reliability
Solution Approach 1:
The scrubber acts as an intermediary component between the first and second compression stages. It removes liquid hydrocarbons and water from the gas stream through adsorption and gravitational separation, preventing these substances from condensing during subsequent compression. This intermediary processing step eliminates hydrocarbon condensation while maintaining a relatively simple overall system design.
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 enhances fluid lift rates and prevents hydrate formation, ensuring reliable operation of gas compressor packages by maintaining the gas in the vapor phase and reducing heavy hydrocarbon content, thus addressing the limitations of conventional systems and reducing downtime and costs.
Implementation Method 1
A heat exchanger is configured to heat the high pressure gas
Implementation Method 2
avoiding precipitation of hydrates as the pressure is reduced (and consequently temperature is lowered)
Data Source
AI summary
Systems and methods are disclosed for conditioning a fuel gas for a gas engine of a multi-stage gas compressor. The system includes a scrubber of the gas compressor, a heat exchanger, a pressure reducing valve, and a pressure vessel. A disclosed method includes causing a stream of gas to flow from the scrubber of the gas compressor to the heat exchanger, adding heat to the gas via the heat exchanger, lowering the pressure of the gas via the pressure reducing valve, providing the gas to the pressure vessel, removing liquids from the gas via a coalescing type filter element of the pressure vessel, and providing the conditioned fuel gas from the pressure vessel to the engine of the gas compressor. The gas is taken downstream from a mist extraction device of the scrubber and the scrubber is part of a last stage of compression in the multi-stage gas compressor.