CNG Power System CO2 Capture Storage Integration
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Solution Overview
Problem
Current systems for onboard CO2 capture and storage in vehicles using compressed natural gas (CNG) are either complex or incur a high energy penalty, particularly for solid oxide fuel cells, and lack an economical and lightweight solution for CO2 storage.
Innovation Solution
A compact and energy-efficient system that utilizes the energy from CNG expansion to compress and store CO2 within the same storage tank, employing a movable partition or membrane to separate CNG and CO2 sections, with the CNG expansion turbine powering the CO2 compressor, reducing the need for a separate CO2 tank and minimizing weight and volume penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a separate CO2 storage tank is used, then CO2 storage capacity is improved, but vehicle weight and volume increase
Solution Approach 1:
The patent combines the CO2 storage function with the existing CNG storage tank by adding a CO2 storage section to it. This merging of functions allows CO2 to be stored in the same tank structure that already stores CNG, eliminating the need for a separate CO2 storage tank and thereby reducing vehicle weight and volume while maintaining CO2 storage capacity
2Quantity of substance
If a separate CO2 storage tank is used, then CO2 storage capacity is improved, but vehicle volume increases
Solution Approach 1:
The patent combines the CO2 storage function with the existing CNG storage tank by adding a CO2 storage section to it. This merging of functions allows CO2 to be stored in the same tank structure that already stores CNG, eliminating the need for a separate CO2 storage tank and thereby reducing vehicle volume while maintaining CO2 storage capacity
3Productivity
If conventional CO2 compression system is used, then CO2 compression function is achieved, but energy consumption increases
Solution Approach 1:
The patent uses the expansion energy from CNG itself to drive the CO2 compression process. The CNG expansion turbine, which naturally expands during fuel delivery, is coupled to the CO2 compressor to provide the compression power. This self-service approach uses the system's own operational energy to perform the compression function without requiring additional external energy input
Solution Approach 2:
The patent merges the CNG expansion process with the CO2 compression process by coupling the CNG expansion turbine to the CO2 compressor. This integration allows the energy from CNG expansion to directly drive CO2 compression, combining two functions into one energy transfer chain and eliminating the need for separate compression energy sources
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 solution enables efficient onboard CO2 capture and storage with reduced energy penalty, allowing for more than 60% of CO2 compression power to be supplied by CNG expansion, and avoids the weight and volume penalties of a separate CO2 tank, while maintaining high energy efficiency through heat exchanger integration.
Implementation Method 1
CNG expansion turbine mounted in a fuel circuit between the storage tank and fuel conversion system powered by expansion of the CNG flowing from the storage tank to the fuel conversion system
Implementation Method 2
a CO2 compressor connected between the fuel conversion system and the storage tank along a CO2 circuit for compressing the CO2
Implementation Method 3
the storage tank comprises a CNG section in which CNG is stored and a CO2 section in which captured CO2 is stored, the CNG section separated from the CO2 section by a movable partition
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3(a)~3(b)
AI summary
CNG power system (1) comprising a storage tank (6) connected fluidically to a fuel conversion system (2) via an energy transfer system (4), the fuel conversion system (2) comprising a power unit using CNG as fuel and generating gas emissions comprising C02, the fuel conversion system comprising a C02 capture unit (16) configured for separating out C02 from the gas emissions. The energy transfer system comprises a CNG expansion turbine (22) mounted in a fuel circuit (8) between the storage tank and fuel conversion system powered by expansion of the CNG flowing from the storage tank to the fuel conversion system, and a C02 compressor (24) connected between the fuel conversion system and the storage tank along a C02 circuit (10) for compressing the C02, power for driving the C02 compressor (24) being supplied in part by power generated by the CNG expansion turbine (22).