The BAG single-membrane biogas storage bag provides flexible buffer storage between gas production and consumption. Gas is contained in a closed membrane envelope whose volume changes as it fills and empties. The bag can be manufactured to fit the available space and the required storage capacity.

Single-membrane construction

The gas-containing envelope is made of polyester fabric coated with PVC on both sides. The textile reinforcement provides tensile strength, while the PVC coating forms the flexible gas barrier. The membrane material has high tear resistance and is resistant to UV exposure and weathering. The membrane sections are welded to form the closed gas envelope.

The bag is designed for non-pressurised gas storage. Its operating conditions and protection settings are coordinated with the gas supply and withdrawal system. The membrane expands as gas enters and contracts as gas is withdrawn, allowing the plant to buffer fluctuations in gas production.

Shape and dimensions to suit the installation

Available shapes include cylindrical bags, cushion-shaped bags and cuboid bags. Length, width, diameter and connection positions are specified to suit the space and gas piping layout. The storage volume is selected for the required buffer capacity.

For a floor-mounted cylindrical bag, the installation area is arranged in a weather-protected room with enough clearance for the membrane to move during filling and emptying. The dimensions of the expanded bag, connection access and service space are taken into account when selecting its position.

Separate gas inlet and outlet

The complete system has a separate flanged gas inlet and flanged gas outlet. Their nominal sizes and positions are selected for the gas flow and piping arrangement. Standard membrane connections are made of HDPE, with the flange configuration matched to the connected pipework.

Connections are sealed at the membrane and joined using the corresponding flange components and gaskets. The arrangement allows the supply and withdrawal lines to be connected separately and accessed for inspection.

A separate condensate drain is provided at the low point of the bag. The two standard gas connections are DN100; other sizes can be selected for the installation.

Protective underlay

A 300 g/m² protective fleece is placed beneath the floor-mounted bag. This separates the membrane from the support surface and reduces direct rubbing against the base. The underlay is sized to cover the bag support area. The base is prepared as a smooth, clean surface suited to the membrane.

Pressure and vacuum protection

The system includes pressure/vacuum protection to limit excessive positive or negative pressure during gas admission and withdrawal. The valve is selected for the permissible conditions of the bag and the required gas flow. Its connection and setting are coordinated with the complete gas system.

The complete package includes the membrane bag, separate gas inlet and outlet connections, condensate drain, safety valve, protective fleece and connecting materials. Dimensions are selected to suit the installation.