ENVIRONTEC DMG double membrane gas holder was firstly designed by our headquarter ENTEC in 1992. The gas holder have been continuously developed with more than 1,000 real project feedbacks and proven the State of Art technology.
In comparison with traditional steel-made gas holder, DMG is low cost, quick to install, and no corrosion maintenance needed. Furthermore, the unique appearance of DMG is definitely a landscape in an Environment Engineering Plant.
In order to serve the market of China and South-East Asian countries with cost-effective price and quick delivery time, Environtec set up an assembling workshop in Shanghai. However, the membrane material is still imported from Austria/Germany directly to ensure the quality.
DMG contains of 3 main parts: external membrane, bottom membrane and inner membrane. The external membrane is always sustaining a positive pressure to maintain the shape and protecting the system against i.e. storm or bad weather. The internal membrane is used for the effective storage of biogas, and it is always floating up and down according to the filling level of the biogas storage. The bottom membrane seals the storage upon the foundation to ensure gas tightness.
An overpressure protection device (hydraulic safety valve) is provided to prevent overpressure at emergency case. Antifreeze can be added to the water sealing for working during cold weather.
Stainless steel rails and Hilti Anchors are used for fast and efficient installation.
Biogas membrane is made of basic fabrics plus special PVC/PVDF coating with flame retardant, fungicide and UV- protection functions. The membrane meets the following criteria: light fastness complying with DIN standard 540047 , flame retardant complying with DIN standard 4102 B1, anti-thermal expansion and contraction performance complying with DIN standard 53361 ,water resistance complying with DIN standard 51635 , ductility complying with DIN standard 53359 .
The external membrane always requires a high strength and high self-cleaning function. The internal membrane and bottom membrane require very good biogas tightness, and remaining chemical-inert from the main components of the biogas i.e. H2S and CH4. The strength of the membranes range is between 4,000 N/5cm and 9,000 N/5cm, which can be chosen according to wind load and snow load calculation.
Air blower is an important part of the double membrane gas holder. Environtec chooses the explosion-proof type blower with special fiber glass FRP materials against possible corrosion on site. The level signal of biogas storage capacity can be used to control the subsequent biogas users, for example, when the level reaches i.e. 90%, the flare is started automatically; or when the level is less than i.e. 20%, all biogas booster , boilers, CHPs are closed automatically.
An electrical control board , IP55, is provided with all automatic control functions and indicating on site the necessary storage level signals and pressure signals.