PR015-242008-Z01 Recompression System Best Practice Guideline

Pipeline operators are under increasing pressure to minimize methane emissions from pipeline blowdowns. The draft methane regulations from Environment and Climate Change Canada (ECCC) have required operators to minimize operational blowdowns. Both the US and Canada have also implemented carbon pricing on methane emissions.

Historically, turbine driven centrifugal or multi-stage reciprocating mobile transfer compression packages have been used by operators to minimize methane emissions from pipeline blowdowns. However, they can only draw the pipeline pressure to approximately 200 psig. The remainder of the gas in the pipeline is then either vented to the atmosphere or flared. These leftover volumes can range between 0.5 to 15 MMSCF. For context, 15 MMSCF is equivalent to 8,000 tCO2e worth of emissions and $640k worth of carbon tax payment in Canada.

While technically feasible solutions exist, the real barrier is economic. Current options for full mobile transfer compression or package combination that can evacuate large volumes (~40 MMSCF+) to near-zero pressure are limited and costly.

To address this, project member companies were surveyed for recompression data during their day-to-day operations. This data was compiled and incorporated into the conceptual design of cost-effective packages aimed at maximizing value without compromising throughput. Major components in each package were selected, sized, and costed. A technoeconomic tool was developed to assist pipeline operators in assessing the technical and economic tradeoffs of each package. Each package was then evaluated using this tool to assess its competitiveness against existing commercial off-the-shelf (COTS) recompression units. Two versions of this tool (i.e., SI and English units) are included with this report and available for use under the terms of the PRCI spreadsheet end user license agreement.

This document is intended to serve as a guideline that provides recommendations on engineering practices for natural gas pipeline recompression. It provides pipeline operators with a framework for assessing the technical and economic feasibility of using recompression units to draw down natural gas pipelines. These guidelines are primarily intended for midstream and downstream pipeline operators, including transmission pipeline operators, storage facility operators, and distribution pipeline operators.