Application of Gas Permeation for Biogas Upgrade - Operational Experiences of Feeding Biomethane into the Austrian Gas Grid

The process design, plant erection and operational experiences of a novel biogas upgrading plant that produces approximately 100m³(STP)/h of fully-fledged natural gas substitute from about 180m³(STP)/h of raw biogas will be presented. The upgrading is based on the membrane separation process Gas Permeation and allows low energy consumption as well as very low methane losses. The quality of the upgraded biomethane is controlled continuously regarding various unwanted or malicious substances to assure the agreement with the quality prescribed by Austrian laws. The produced biomethane is introduced to the natural gas grid and delivered to the households of the neighboring city Bruck/Leitha in Lower Austria. During the summer months the gas consumption in the local grid is far too small compared to the produced biomethane stream and the excessive biomethane is compressed to 60bar and fed into the regional natural gas grid. The process of Gas Permeation is continuous, stable and relatively easy to handle and to control; furthermore, no regeneration or chemicals are needed. Additionally, a dynamic process simulation model has been developed to gain knowledge of startup and shutdown procedures, as well as to test control strategies and parameterize the implemented PID controllers.