How it works – the basics
The triple membrane biogas holder is in effect two balloons that are held squeezed together in a tight constricting space. One balloon is filled with biogas, the other with air.
When the Anaerobic Digestion plant is producing more biogas than can be used, instead of losing money by flaring (or burning) off the excess (or even worse, venting it to atmosphere), it is pumped into the ‘Gas’ storage balloon for use later. To accommodate this added volume of biogas, air is simultaneously removed from the ‘Air’ balloon.
When more biogas is required than is being produced by the AD plant, air is pumped into the Air balloon forcing biogas out of the Gas balloon at a finely controlled pressure and flow rate. Because changes in volume are traded between Gas and Air balloons the total pressure contained by the Outer Membrane is constant. By fixing the structure to the ground via the Outer Membrane, this constant internal pressure is converted into a tension in the membrane giving it a rigidity to resist external loads.
Simple failsafe pressure relief valves ensure the system can never be over-pressurised, and having two independent sources of pressure (Gas and Air) means the system can never be under-pressurised.
Our triple membrane biogas holder is held in place via a patented system of stainless steel hoops that are resin anchored into a concrete base and rolled steel tubes which are fed into a pocket that is attached to the Outer membrane. The steel tube in the pocket is threaded through the hoops thereby securing the biogas holder on the base. The installation process is generally completed within one day.
Uniquely, our gas holder can be installed directly on top of the ground as a temporary structure. A ring of concrete or steel ballast weights can be supplied which overcomes the need for a concrete base. This dramatically improves the flexibility of the system and even opens up the opportunity to introduce our gas holder as a temporary storage device or additional / emergency storage volume if your existing system fails or is being shut down for planned maintenance etc.