As Biogas generally called, are all gases which result from microbial degradation of organic matters under anoxic conditions (under exclusion of oxygen). In addition to the classical biogas, there is also digester gas from sewage treatment plants as well as landfill gas, which results from fermentation of solid biomass/bio-waste, food leftovers, organic fertilizers, plant remains and energy crops.

• Thermal flow meter for direct measurement of normal volumetric or gas mass flows with integrated humidity correction
• Flow rate measurement unaffected by pressure and temperature
• For gas temperature up to 130°C and gas pressure up to 1,3 bar
• Compact and rugged design for exceptional reliability
• Easy to install and service
• Unmatched accuracy due to digital signal processing
• Expandable due to modular design
• EEx [ed] Zone 1 or Zone 2 optionally available

THE SYSTEM

The field transmitters of the COMBIMASS®eco-bio+ series are suitable especially for biogas flow measurement. The instruments can be employed for process temperatures up to 130°C and are available in different explosion proof versions. The flow transmitters apply thermal dispersion technology in order to measure directly the normal volumetric or gas mass flow, regardless of the operating pressure and temperature of the medium.

All units of the COMBIMASS® series are characterized by high-performance digital signal processing. Important features of the transmitter electronics for the purposes of practical operation are the temperature compensation and the opportunity to select different measuring modes (choice between constant current or constant temperature principle). The flow transmitter can be combined with a wide range of different sensors of the COMBIMASS® family and assembled individually according to the specific application.

While the gas composition (except during on and driving off phase) in liquid fermentation plants changes usually only very slowly over the day, the gas flow is subject to certain short term fluctuations, as they are caused for example by the agitator or different humidity content under variations in temperature. Therefore it is appropriate that at each digester a thermal mass flow meter is installed firmly and connected with the Docking station.

The COMBIMASS®eco bio+ flowmeter is developed particularly for the fermentation gas market, which is available in two different ex-versions: for the installation in ex-zone 1 with a compact and compression-proof stainless steel housing as well as for zone 2 with a cheaper aluminum housing. The electronics of the COMBIMASS®eco-bio + zone 1 is located in a dual compartment stainless steel enclosure. For transmission of the flow signal there are an isolated 4-20 mA analog output as well as a field selectable pulse output are available. Optionally a 10 digits LED display with control panel is available for both housings for the indication of actual flow rate or totalized flow as well as for field programming of the flow meter.

The COMBIMASS®eco bio+ flowmeter for the installation in biogas uses a 2-Pin-Sensor with 12 mm in diameter, which also supplies in this damp and dirty gas a stable signal. The sensor head is completely in high-grade steel manufactured and thus insensitive from a part to corrosion.

Each flow meter will be tested prior to shipment and calibrated at our CAMASS®calibration centre under actual operating conditions (piping layout, gas composition, pipe diameter, flow direction,...).

APPLICATIONS

• Gases with methane from fermentation plants using different technologies
• Digester gases from wastewater treatment plants
• Gas and gas mixtures of known composition (f.e.  exhaust air, process gas, combustion gases such as methane, propane, natural gas or landfill gas) with other flowmeter from COMBIMASS^® family