Expander Power Extraction from High-Pressure Fuel Gas
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Solution Overview
Problem
Existing plant technologies do not effectively utilize the pressure energy of high-pressure fuel gas to improve output and efficiency.
Innovation Solution
Incorporating expanders in the fuel supply line to extract power from high-pressure fuel gas, with optional heaters upstream of expanders to enhance power extraction, and utilizing waste heat from compressors to further improve efficiency, along with CO2 rich gas processing for enhanced oil recovery and carbon sequestration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high-pressure fuel gas is supplied directly to the plant without power extraction, then the fuel gas can be used immediately for power generation or heating, but the pressure energy of the fuel gas is wasted and the overall plant efficiency is reduced
Solution Approach 1:
The high-pressure fuel gas supplies power to the compressor that pressurizes the fuel gas itself, creating a self-service system where the fuel gas contributes to its own pressurization. This is achieved by extracting power from the fuel gas through an expander and using that power to drive the compressor, eliminating the need for external power sources and reducing overall energy loss.
Solution Approach 2:
Instead of discarding the pressure energy of the high-pressure fuel gas, the system recovers this energy through an expander that extracts power from the fuel gas during expansion. The recovered power is then utilized to drive the compressor and other plant operations, converting what would be wasted energy into useful work.
2Productivity
If an expander is added to extract power from high-pressure fuel gas, then the overall plant efficiency and output are improved, but the device complexity and initial investment increase
Solution Approach 1:
The expander serves multiple functions: it extracts power from the high-pressure fuel gas to increase plant output, and simultaneously the extracted power drives the compressor and other plant operations. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component.
Solution Approach 2:
The system creates a feedback loop where the expander extracts power from the fuel gas, and this extracted power is fed back to drive the compressor and support plant operations. This feedback mechanism ensures that the additional complexity of the expander is compensated by the useful work it performs within the system.
3Power
If the fuel gas is not preheated before entering the expander, then the plant configuration is simpler, but the power extraction efficiency at the expander is reduced
Solution Approach 1:
The fuel gas is preheated in a heater before entering the expander, which is a preliminary action that improves the subsequent power extraction process. By heating the fuel gas beforehand, the expander can extract more power from the same pressure differential, enhancing overall system efficiency.
Solution Approach 2:
The heater is integrated into the fuel supply line, merging the heating function with the fuel delivery system. This combination allows for efficient heat transfer and ensures the fuel gas is properly heated before expansion, while avoiding the need for separate, standalone heating equipment.
4Loss of energy
If waste heat from compressors is not utilized, then the system operation is simpler, but the overall energy efficiency and output of the plant are reduced
Solution Approach 1:
The waste heat from the compressor, which would normally be discarded as a harmful byproduct, is converted into a beneficial resource by using it to preheat the fuel gas in the heater. This transforms energy loss into useful thermal energy that improves expander performance and overall plant efficiency.
Solution Approach 2:
Instead of discarding the waste heat from the compressor, the system recovers this thermal energy and utilizes it for heating the fuel gas before it enters the expander. This recovery process reduces energy loss and improves the overall thermodynamic efficiency of the plant.
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 configuration effectively utilizes pressure energy to enhance plant output and efficiency, recovers additional power, and optimizes energy use through waste heat recovery and CO2 processing.
Implementation Method 1
at least one expander disposed in the fuel supply line and configured to extract power from the high-pressure fuel gas by expanding the high-pressure fuel gas
Implementation Method 2
a heater, disposed in the fuel-supply line at an upstream side of an expander of the at least one expander, for heating the high-pressure fuel gas flowing into the expander
Implementation Method 3
at least one compressor, disposed in the CO2 rich gas line, for pressurizing the CO2 rich gas
Implementation Method 4
The heater is configured to heat the high-pressure fuel gas by using waste heat of the at least one compressor
Data Source
AI summary
A plant includes a fuel supply line for supplying high-pressure fuel gas; and at least one expander disposed in the fuel supply line and configured to extract power from the high-pressure fuel gas by expanding the high-pressure fuel gas.