CO2 Brayton Cycle CHP System for Solid Fuel Combustion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing combined heat and power (CHP) systems face challenges in efficiently utilizing waste organic resources for small-scale applications, particularly due to high costs and inefficiencies in converting organic materials into usable heat and power, as well as the need to capture and sequester CO2 from exhaust gases.
Innovation Solution
A closed, oxy/solid organic fired, CO2 Brayton cycle system is introduced, utilizing high-purity oxygen for combustion and CO2 as the working fluid, which allows for efficient heat transfer and power generation, reducing the need for CO2 capture and increasing power output by 60% due to CO2's higher density compared to air.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gasification of organics into syngas is used to convert solid fuel into hydrocarbon gas for combustion, then power generation is achieved, but system cost increases significantly especially at smaller power/heat applications
Solution Approach 1:
The patent extracts and eliminates the gasification step from the traditional organic-to-power conversion process. By directly combusting organic materials in an oxy-fuel combustion chamber, the system removes the complex and expensive gasification equipment while maintaining power generation capability through direct combustion of organics to drive the CO2 Brayton cycle turbine.
Solution Approach 2:
The patent replaces the mechanical gasification conversion process with a direct chemical combustion process. Instead of converting solids to gases through thermal gasification, the system directly combusts organic materials in an oxygen-enriched atmosphere, substituting a simpler combustion mechanism for the complex gasification system.
2Power
If traditional air-breathing Brayton cycle is used, then power generation is achieved, but CO2 capture becomes necessary increasing system complexity and cost
Solution Approach 1:
The patent uses an oxygen-enriched inert atmosphere instead of air for combustion. By replacing air (which contains nitrogen that forms NOx and dilutes exhaust) with pure or enriched oxygen, the combustion exhaust consists primarily of CO2 and water vapor, creating a naturally concentrated CO2 stream that eliminates or simplifies CO2 capture requirements.
Solution Approach 2:
The patent converts the typically harmful CO2 emission from combustion into a beneficial concentrated CO2 product. By using oxy-fuel combustion, the CO2 that would normally be dispersed and difficult to capture in air-breathing systems becomes highly concentrated in the exhaust, turning an environmental liability into a valuable resource for sequestration or utilization.
3Use of energy by moving object
If organic combustion is used to drive externally fired engines, then heat to power conversion is achieved, but nitrogen oxide emissions are generated
Solution Approach 1:
The patent eliminates nitrogen oxide emissions by conducting combustion in an oxygen-enriched atmosphere free of nitrogen. Without nitrogen present during combustion, NOx formation is prevented at the source, allowing heat-to-power conversion through the CO2 Brayton cycle without generating nitrogen oxide pollutants.
Solution Approach 2:
The patent uses pure oxygen or oxygen-enriched air as a strong oxidant instead of atmospheric air. This accelerated oxidation process in an oxygen-only environment enables complete combustion of organics to CO2 and water vapor without forming nitrogen oxides, maintaining efficient heat-to-power conversion while eliminating NOx emissions.
Data Source
AI summary
A combined heat and power (CHP) system and a method of operating is provided. The CHP system includes an oxygen-air separation device. A combustion chamber has an inlet coupled to the oxygen-air separation device. The combustion chamber receives an expanded heated CO2 working gas for combustion of solid fuel and generates a CO2 exhaust gas. The expanded heated CO2 working gas comprising at least a portion of the CO2 exhaust gas. A heat exchanger receives combustion gases and outputs a cooled CO2 working gas. A turbine is provided having a compression section and an expansion section, the compression section configured to receive and compress the cooled CO2 working gas and to direct it to the heat exchanger. The turbine receives a heated CO2 working gas at the expansion section and expands the heated CO2 working gas. In an embodiment, CO2 products may be generated from the system.