Best Purging Practices for Minimizing Methane Emissions

Overview

Main Objective

The project will establish best purging practices for the elimination or avoidance of methane emissions during pipeline construction, commissioning, and maintenance. This includes a literature survey and an examination of previous work related to different methods of avoiding and/or eliminating methane emissions.

Public Abstract

The objective of this project is to establish best purging practices for the elimination or avoidance of methane emissions during pipeline construction, commissioning, and maintenance. This will include a literature survey and examination of prior work in these areas related to different methods of avoiding and/or eliminating methane emissions.

Anticipated Results: The deliverables of this project will be a comprehensive literature survey that identifies and details various methods to reduce and/or eliminate methane emissions due to purging and/or blowdown procedures. The technology survey will focus on already existing methods, improvements to these methods, and new technologies and techniques. The different alternatives will be described in relation to the operating scenario and environment as described in American Gas Association or AGA XK1801 "Purging Manual." In addition to a detailed review of commercially available equipment and techniques, a final report will also include operational recommendations and guidance to determine the best practices associated with each technique and method. The review of potential alternatives will also include economic examples and methane emissions avoidance quantification calculations to provide context for comparing the feasibility and benefits of different methods.

Potential Impact on Safety: Methane releases and emissions can occur in transmission, distribution, and gathering pipelines at any point across the system. To achieve decarbonization and climate change goals, the government and the natural gas industry are working to minimize methane emissions. Avoidance of methane emissions from purging operations have both economic benefits for operators and environmental benefits for the community. Using alternatives to venting natural gas into the atmosphere also increases public trust in the natural gas industry and provides a safer work environment for pipeline and gathering system operators.

Summary and Conclusions

The purging alternatives identified and described in this report were gathered through communications and feedback with the project's Technical Advisory Panel (TAP) members, which is composed of industry subject-matter experts, operators, consultants, and equipment providers and manufacturers. This feedback is useful in not only identifying purging equipment and practices, but in learning from their experience about how to best implement different methods for different operations. Recent efforts by gas operators to reduce methane emissions have created questions about what equipment and/or practices are best suited for different emission mitigation scenarios. This report details purging alternatives (purging gas piping systems into and out of gas service) and provides details about some of the specific equipment being used in the field today. This report also provides some of the best practices and lessons learned from various operators, contractors, service providers and manufacturers implementing alternative purging practices. Objectives of this work includes:

• Detailed information about the opportunities and challenges associated with each identified purging alternative method.
• Results from TAP group surveys regarding the implementation feasibility of various alternative purge methods.
• Best practices and guidance collected from interviews with TAP members and industry experts in purging alternative methods.
• Operational procedures provided by operators and lessons learned in their implementation. The project team worked to identify and establish best purging practices for the elimination or reduction of methane emissions during pipeline purging operations.

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