Air-Breathing Engine Reformer Back-Pressure for Lower Compression Work
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Solution Overview
Problem
Existing gas-to-liquid systems face significant challenges in efficiently converting flare gas into valuable products due to high compression work requirements, environmental pollution from venting and burning, and inefficient combustion, which leads to substantial greenhouse gas emissions.
Innovation Solution
The system employs an air-breathing engine reformer with increased back-pressure and a turbo-expander to reduce compression work, utilizing a turbo-expander heat exchanger system and reactive separation synthesis to convert flare gas into syngas, which is then processed into methanol or other valuable products, while incorporating a recuperative heat exchanger to enhance energy recovery and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional compression systems are used in gas-to-liquid systems, then the system can achieve required synthesis pressures, but the compressor work and energy consumption become excessively high
Solution Approach 1:
The system dynamically adjusts engine operating parameters including compression ratio, inlet manifold air temperature, inlet manifold air pressure, and engine speed to optimize the balance between producing sufficient syngas at required pressure levels and minimizing the compression work needed for downstream synthesis processes
Solution Approach 2:
The invention changes key operating parameters of the engine reformer system, particularly increasing back-pressure from standard 1-2 bar to up to 5 bar, and adjusting compression ratios and temperatures to reduce the pressure differential that must be overcome by compressors, thereby reducing compressor work while maintaining required synthesis pressures
2Productivity
If air-breathing engine reformers are used to convert flare gas, then the system can process hydrocarbon gases, but high compression work requirements increase operating expenses
Solution Approach 1:
The engine reformer system is configured to self-pressurize the syngas production process through increased back-pressure operation (up to 5 bar), reducing the need for external compression energy input while maintaining productivity in converting flare gas to syngas and subsequent liquid products
3Power
If standard back-pressure operation is used in engine reformers, then the engine can operate efficiently, but the pressure differential requires excessive compression work downstream
Solution Approach 1:
The invention changes the back-pressure operating parameter from standard 1-2 bar to elevated levels of up to 5 bar, which reduces the pressure differential that downstream compressors must overcome, thereby reducing downstream compression work while the engine maintains efficient operation through dynamic adjustment of other parameters including compression ratio and inlet conditions
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 reduces compressor work, lowers capital and operating expenses, and achieves negative CO2e emissions by converting flare gas into valuable products like methanol, ethanol, or ammonia, making the process self-sustaining and environmentally friendly.
Implementation Method 1
energy recovery from the engine reformer exhaust stream by expanding the stream in a turbo-expander
Implementation Method 2
heat exchangers, compression system components, and heat exchangers to prepare the syngas for the downstream synthesis reactors
Implementation Method 3
partially oxidizing the fuel source in an air-breathing reciprocating engine to produce a syngas mixture
Data Source
AI summary
There are provided systems and methods for using partial oxidation to produce an end product from hydrocarbon gases, such as flare gas. There are provided methods and systems to minimize the amount of compression work needed for an air breathing engine reformer in a gas-to-liquid system and method by one or more of: (a) reducing the amount of nitrogen; (b) increasing back-pressure of the engine reformer from standard 1 or 2 bar, to up to 5 bar; (c) use of a turbo-expander to recover much of the compression work, thus lowering the cost, among other efficiencies, to operate a plant; and (d) utilizing an intensified synthesis loop to achieve acceptable methanol synthesis at lower overall pressure. In an embodiment, the end product is methanol.