Nested CO₂ Power Cycle Design for Efficiency Without Emission Increase
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Solution Overview
Problem
Current power production systems using CO2 as a working fluid face limitations in efficiency and power output while also emitting CO2, NOx, and other combustion products into the atmosphere, despite efforts to optimize recuperative heat exchangers and external heat sources.
Innovation Solution
The system employs an independent heat source to heat a high-pressure CO2 stream from a power production cycle, which is then expanded and recombined with the primary cycle to enhance power production and heating, utilizing shared equipment to increase efficiency and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an independent heat source is used to heat compressed CO2 stream beyond internal recuperation, then power production capacity and efficiency are increased, but system complexity and capital expenditures increase
Solution Approach 1:
The patent implements a nested cycle configuration where a second power production cycle is embedded within the first cycle. The independent heat source heats a portion of the compressed CO2 stream, which then expands through a second turbine to generate additional power. The heated stream is recombined with the primary cycle, creating a nested structure that increases productivity while managing complexity through systematic integration.
Solution Approach 2:
The CO2 compression system serves multiple functions: it compresses CO2 for the primary power production cycle and simultaneously provides compressed CO2 for the second cycle that utilizes the independent heat source. This multi-functionality allows the same equipment to support both cycles, reducing the need for separate compression systems and thereby managing device complexity while increasing overall power production capacity.
2Use of energy by moving object
If additional heating is supplied to the CO2 work stream using external heat sources, then efficiency is improved, but equipment requirements and capital expenditures increase
Solution Approach 1:
The second power production cycle is nested within the first cycle, with the independent heat source providing additional heating to a portion of the compressed CO2 stream. This nested configuration enables efficiency improvement through additional heating while managing equipment requirements by integrating the second cycle into the existing primary cycle infrastructure.
Solution Approach 2:
The CO2 stream is segmented into different portions: one portion undergoes internal recuperation heating in the primary cycle, while another portion is directed to the independent heat source for additional heating. This segmentation allows efficient use of both internal and external heat sources without requiring the entire system to be redesigned, thereby improving efficiency while controlling equipment requirements.
3Device complexity
If CO2 is vented to the atmosphere from combustion, then the power production system is simpler, but harmful emissions increase
Solution Approach 1:
The patent uses CO2 as the working fluid throughout the power production cycles, creating an inert atmosphere that prevents the formation of harmful combustion products. The CO2 is recycled through the system and not vented to the atmosphere, eliminating harmful emissions while maintaining system simplicity through the use of a single working fluid that serves both as the medium for power production and as an emission-free exhaust.
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 increases power production capacity and efficiency while minimizing atmospheric emissions by providing additional heating beyond internal recuperation, reducing the need for new equipment and capital expenditures.
Implementation Method 1
an independent heat source can be used to heat at least a portion of a high pressure recycle CO2 stream from the power production cycle
Implementation Method 2
the so heated stream can be rejoined to the power production cycle in a variety of manners to achieve the additional heating of the recycle CO2 work stream. Advantageously, the so-heated recycle CO2 stream can be expanded for additional power production
Implementation Method 3
a first power production cycle wherein a recycled CO2 stream is subjected to repeated compression, heating, combustion, expansion for power production, and cooling
Implementation Method 4
recuperative heat exchange optimization has been pursued, such as via hot gas compression or through external heat sources
Data Source
AI summary
The present disclosure relates to systems and methods useful for power production. In particular, a power production cycle utilizing CO2 as a working fluid may be combined with a second cycle wherein a compressed CO2 stream from the power production cycle can be heated and expanded to produce additional power and to provide additional heating to the power production cycle.