DOUBLE MEMBRANE GAS HOLDER

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DOUBLE MEMBRANE GAS HOLDER

EnvironTec DMG double membrane gas holder was firstly designed by ENTEC in Austria (since 1992） with originally a pressureless gas bag only inside the ourside steel shell.   After many years development, Environtec have achieved many DMG projects all over the world.

In comparison with traditional steel-made gas holder, Double Membrane Gas Holder is widely used and developed with its advantages of low cost, fast installation , no corrosion maintenance and so on. Moreover, the unique appearance of DMG alywas make it a landscape located in an environmental protection job site.

1、FUNCTION

Double Membrane Gas Holder 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 protect the system against bad weather like storm, typhoon, etc. The internal membrane is used for the effective storage of biogas, and it is always floating up and down according to filling or utilizing the biogas. The bottom membrane seals the storage upon the foundation to ensure gas tightness.

An overpressure protection device (hydraulic or mechanic safety valve) is provided to prevent overpressure at emergency case. EnvironTec uses special stainless clamping rails and Fisher/Hilti anchors  to fix the membranes on concrete surface. No pre-cast items  are required which makes the  civil work more convenient.

2、DESIGN PARAMETER

Volume：       20 -8,000m3

Design storage pressure： 10-35mbar

Design snow load： 0-150kg/m2

Design wind load：         0-150km/h

3、MEMBRANE

EnvironTec biogas membrane is customer-made with many unique feathers i.e. flame retardant, antibacterial, gas-tightness, and anti-ultraviolet. The membrane quality meets the following standards: the light fastness meets the DIN 54004 7 standard, the flame retardant performance conforms to the DIN 4102 B1 design standard, and the thermal expansion and contraction resistance conforms to DIN53361standard, waterproof to DIN 51635 and ductility to DIN 53359 standard.

The external membrane is designed with high strength and self-cleaning function. The internal membrane and bottom membrane require biogas tightness, and chemical-resistance for the main components of the biogas i.e. H2S and CH4. The strength of the membranes range is between 4,000 N/5cm to 9,000 N/5cm, which can be chosen according to wind load and snow load calculation.

4、CONTROL UNIT

Air blower is important for double membrane gas holder. EnvironTec chooses the explosion-proof type blower with FRP materials for outdoor operation. It is recommended for one use and one standby at job site.

Level transmitter is also essential for monitoring the gas holder level, The level signal of biogas storage capacity can be used to control the biogas-user. For example, when the level reaches i.e 90%, the flare ignites automatically; when the level is less than i.e 0%, the biogas booster, boilers, CHPs are closed automatically.

5、STRUCTURE

1. External membrane                           8.   Non-return valve

2. Internal membrane                           9.   Pressure regulating device

3. Bottom membrane                           10.  Level measurement

4. Clamping rail                                   11.  Inspection window

5. Air support blower                           12.  Foundation

6. Gas pipe                                         13.  Air-hose

7. Safety device

6、CHARACTERISTIC

*All membranes from Germany        *Designed by EnvironTec Austria        *Assembled in Shanghai

*Accurate shaping analysis              *Low pressure fluctuation                  *Low pressure fluctuation

*Separated air inlet and outlet         *Prevent air "short-circuiting"             *Quick installation