Rich Engine Control for Flare Gas to Syngas Conversion
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Solution Overview
Problem
There is a long-standing need for systems and methods to convert uneconomic hydrocarbon-based fuels, such as flare gas, into value-added products like methanol, ethanol, and other chemicals, while efficiently operating air-breathing engines under rich conditions, as conventional engine control systems are not effective in producing syngas with a desirable H2/CO ratio.
Innovation Solution
The development of a spark ignited reciprocating engine with a control system that monitors and adjusts the fuel-air ratio, using sensors and actuators to maintain engine operation, and incorporates a Lambda sensor for rich operation, along with a gas-to-liquid reformer system that includes sensors for monitoring fuel composition and gaseous products, enabling the production of syngas suitable for downstream synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional engine control systems are used, then the engine can operate under standard conditions, but the H2/CO ratio of produced syngas is not desirable for downstream synthesis
Solution Approach 1:
The patent implements dynamic control of engine parameters including variable spark timing, variable intake air flow, and variable fuel flow to maintain optimal H2/CO ratio under rich operating conditions. The control system continuously adjusts these parameters based on feedback from sensors monitoring exhaust gas composition and engine performance, enabling the engine to operate dynamically in the rich regime while producing syngas with desirable H2/CO ratio for downstream synthesis.
2Manufacturing precision
If the engine operates under rich conditions to produce syngas, then the H2/CO ratio improves, but the combustion stability and engine reliability deteriorate
Solution Approach 1:
The patent employs a feedback control system that uses sensors to monitor exhaust gas composition (including H2, CO, and hydrocarbon levels), engine speed, and combustion characteristics. This feedback information is fed to the control system which adjusts spark timing, air flow, and fuel flow in real-time to maintain stable combustion under rich conditions while achieving the desired H2/CO ratio in the produced syngas.
3Object-generated harmful factors
If flare gas is burned or vented conventionally, then the handling is simple, but greenhouse gas emissions increase
Solution Approach 1:
The patent converts the harmful effect of flare gas combustion (greenhouse gas emissions) into a beneficial outcome by using the engine to produce syngas with controlled H2/CO ratio, which is then fed to downstream synthesis units to produce liquid fuels and chemicals. This process transforms what would be wasted or harmful emissions into valuable products, reducing greenhouse gas emissions while generating economic value from flare gas.
4Manufacturing precision
If sensors and control systems are added to monitor fuel-air ratio and engine operation, then the syngas production quality improves, but the system complexity increases
Solution Approach 1:
The patent integrates multiple functions into the control system, including monitoring of fuel-air ratio, exhaust gas composition analysis, engine performance optimization, and syngas quality control, all managed by a single sophisticated control unit. This multi-functional approach achieves high syngas production quality with desirable H2/CO ratio while managing system complexity through consolidation of control functions.
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 allows for the conversion of flare gas into economically viable products with negative CO2e emissions, achieving a H2/CO ratio suitable for synthesis, reducing greenhouse gas production, and enabling efficient operation of air-breathing engines under rich conditions.
Implementation Method 1
a spark ignited reciprocating engine for a rich mixture of hydrocarbon fuel and air that when burned produces a syngas
Implementation Method 2
incorporates a Lambda sensor for rich operation
Implementation Method 3
a gas-to-liquid reformer system that includes sensors for monitoring fuel composition and gaseous products
Data Source
AI summary
There are provided systems and methods for using fuel rich partial oxidation to produce an end product from waste gases, such as flare gas. Lambda sensor modifications and other control parameters that provide closed-loop mixture control at extremely fuel-rich operating conditions utilizing feed-forward and feedback approaches, physics-based engine models, novel use of a lambda sensor (O2-based sensor), sensors with intermittent contact with the gas stream. In an embodiment the system and method use air-breathing engines having control systems, control parameters, sensors and input/output (I/O) for the fuel rich (ER of 1.2 and greater), partial oxidation of the flare gas to form syngas. In embodiments the syngas is further converted into an end product. In an embodiment the end product is methanol.