Mobile CNG Vessel and Unloader for Compressor Emissions Testing
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Solution Overview
Problem
Compressors often face challenges in emissions testing due to insufficient gas supply or composition, leading to frequent and costly testing, as well as failed tests due to lower load factors and higher emissions from non-standard gas compositions, which complicates infrastructure and operational requirements.
Innovation Solution
A mobile natural gas vessel and unloader system that provides sufficient gas supply and recirculates compressed gas to maintain optimal pressure and flow rates, enabling emissions testing at or above 90% load, thereby reducing testing frequency and improving pass rates by using a mobile CNG storage system and unloader to ensure consistent gas supply and consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If emissions testing is performed at below 90% load due to insufficient gas supply or composition, then testing can be conducted with available infrastructure, but testing frequency increases and pass rates decrease
Solution Approach 1:
A mobile gas supply vessel is introduced as an intermediary component to provide the necessary gas supply for high-load emissions testing. The vessel connects to the compressor system and delivers standardized natural gas, enabling tests at ≥90% load even when local infrastructure cannot provide sufficient gas supply or composition control.
2Device complexity
If emissions testing is performed at below 90% load, then infrastructure requirements are reduced, but emissions exceed tolerance windows and tests fail
Solution Approach 1:
The system changes the gas composition parameter by supplying standardized natural gas from the mobile vessel, and changes the load factor parameter by enabling operation at ≥90% load. These parameter changes ensure emissions fall within EPA tolerance windows while maintaining testing reliability.
3Object-generated harmful factors
If pipeline gas is used for compressor fuel during emissions testing, then emissions are reduced, but additional infrastructure and operational complexities are required
Solution Approach 1:
The mobile gas supply vessel provides a temporary, dedicated gas supply solution specifically for emissions testing duration. Rather than permanently connecting to pipeline gas infrastructure, the portable vessel delivers standardized gas only when needed for testing, avoiding long-term infrastructure commitments and operational complexities.
4Productivity
If gas supply is increased to achieve ≥90% load, then testing frequency is reduced, but gas supply infrastructure must be enhanced
Solution Approach 1:
The mobile gas supply vessel provides a dynamic, flexible gas supply solution that can be deployed and relocated as needed. The system adapts to different testing locations and compressor configurations without requiring fixed infrastructure installation, maintaining mobility and flexibility while enabling high-load testing 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
The system allows for compliant emissions testing at reduced frequencies and improved pass rates by ensuring optimal operating conditions, reducing costs and complexities associated with frequent testing and higher emissions from non-standard gas compositions.
Implementation Method 1
reducing, via the unloader, a pressure of compressed gas received at the inlet of the unloader
Implementation Method 2
recompressing, via the compressor, the reduced pressure gas received from the unloader
Data Source
AI summary
A mobile compressed natural gas (CNG) vessel and unloader are used to supply CNG to a compressor during regulatory emissions testing of the compressor (e.g., U.S. EPA's Quad J testing). CNG output by the compressor is recirculated to an inlet of the unloader so that it is reused during the emissions testing. Lean CNG from the vessel may be used to power the compressor during the testing. The unloader ensures that the compressor is run at at least a predetermined load factor during the emissions testing.