Methane is the second most abundant anthropogenic greenhouse gas (GHG) after carbon dioxide (CO2). It is estimated1 that the concentration of methane in the atmosphere is approximately 2.6 times higher than the pre-industrial levels (1750) and this contribute for at least a quarter of the global warming. Methane is a more potent GHG than CO2, as it attracts more heat per unit of mass than CO2.
As methane is the main component of natural gas, a strong reduction of its emissions in the atmosphere is paramount.
The turbomachinery normally used in the Pipeline sector frequently release emissions of natural gas: its recovery represents one of the many challenges and opportunities the industry has. To ensure that future technical developments and new machinery contribute to mitigate and if possible to eliminate the gas emissions is a key factor for the industry to comply with increasing regulatory limits as well as perform voluntary actions.
Baker Hughes and Enagás have developed a methane emissions recovery system able to:
- reduce emissions capturing gas vent flows as primary vents of centrifugal compressor seals and the compressor loop blowdown vent
- reinject it into a plant live section, as station suction header instead of venting on atmosphere
- reuse part of this gas vent flow for preheating the gas turbine fuel.
This methane emissions recovery system has been successfully installed and commissioned in Spain at the Enagás’ Lumbier compressor station and will save about 3,400 tCO2e per year2.
This project is included in Enagás’ Decarbonization Strategy, committed to reach carbon neutrality by 2040 and focused on prioritize measures with the greatest impact on its emissions reduction. Methane emissions reduction initiatives are a key priority.
The scope of this paper is to describe the methane emissions reduction system experience acquired by Enagás as operator and Baker Hughes as OEM.