COMBIMASS® series for Process Monitoring and Control

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.

• Combination of biogas flow metering and biogas analysis ensure the best achievable accuracy under field conditions
• Compensation of temperature, pressure, humidity and changing gas composition allow the determination of dry biogas flow at standard conditions according DIN1343  – all flow meters will be supplied with calibration certificates / recalibration certificates
• Easy installation at site, low maintenance of flow meter and analyzer cabinet, special maintenance contracts for gas analyzer cells to en-sure high accuracy, reliability and availability of data
• External access/ data transmission to central server possible
• Manipulation-safe versions of meter can be supplied

Modern biogas fermentation plants cannot meet commercial and environmental requirements without appropriate measuring and analysis technique. As well, process and operational safety becomes more and more important facts. CDM- and Monitoring projects require, besides high accuracy of measured values, a traceable visualization, storage and monitoring as well as easy and reliable maintenance of the equipment at site. All equipment must be delivered with calibration certificates.

For the economical and safe operation of the fementation plant, it is likewise necessary to consider the gas composition and quantity of the individual digester stages. 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 subjected to certain short term fluctuations as they are caused for example by the agitator or different humidity content under variations in temperature. There¬fore it is appropriate to combine flow metering and analysis, to correct actual flow by actual gas composition. In dry bed fermentation stages, the measuring cycle must be, if necessary adapted. Here not only the gas flow but also the gas composition change substantially. The methane concentration can vary from 15 to 70 Vol.-%. A combination of the measurement of volume with the gas analysis is inevitable if the values are to exhibit an acceptable accuracy.

Mainly all available technologies to measure biogas flow determine wet gas flow at operational pressure and temperature. Because of different and changing properties of biogas, there is no custody transfer equipment available. So be-sides common temperature and pressure compensation, a further humidity correction, if gas composition will change, becomes necessary. The COMBIMASS® flow meter eco-bio+ HC can meet all these requirements and measures there-fore the dry biogas flow at standard conditions according DIN 1343. The applied thermal dispersion technology has a further advantage compared to Vortex-, ultrasonic and differential pressure flow meters. The accuracy at low gas speed is even very high and all corrections (besides gas composition correction) can be done in the flow meter without additional devices (no additional sensor and/or compensation calculator necessary). During calibration of the flow meter in the CAMASS® Calibration Lab, operation conditions like gas composition, pressure, temperature and piping orientation are already taken into consideration to achieve the best accuracy and repeatability. Special manipulation-safe versions can be supplied.

Gas analysis stations require a high technical expenditure, which settles in the long run also in the purchase price and in maintenance costs, to achieve long-term accuracy and reliability. If several gas analysis stations are used, not only the acquisition and maintenance costs will add up, but also measurement uncertainties, so that a trend is essentially crucial. If an analysis station must be returned for maintenance, no current data during this time will be available for the control of the process and historical trends of gas composition. Or expensive specialists must be sent to the sites for local service and maintenance.

Binder solves this problem with two different kinds of equipment:

• The COMBIMASS® GA-s Docking Station as a “2-in-1” solution having a portable analyzer in a cabinet with valves, pumps, SPC and different kinds of data transmission or
• The COMBIMASS® GA-s Click! Analyzer Cabinet as a complete modular system with DIN-rail modules for pumps, valves and gas cells.

While using Binder´s portable analyzer in the COMBIMASS® GA-s Docking station, a spare analyzer can be supplied by Binder during maintenance and repair times. All parts of the cabinet can be replaced at site by local contractor or operator. While using the Click! system, modules can be replaced by the enduser and serviced/maintained at Binder.