Gas flow measurement with integrated H2-Compensation

Flow measurement and analysis of syngas

Volumetric flow measurements in syngas (e.g., from wood gasifiers) are not trivial because of fluctuating gas compositions. Syngas is a multicomponent gas mixture consisting of a nonflammable nitrogen / carbon dioxide / combustible hydrogen and carbon monoxide as well as small amounts of hydrocarbons. Depending on the material to be gasified and variations in material quality, the gas composition of the resulting gas also varies. Each COMBIMASS(R) thermal mass flow meter is only calibrated to a specific gas composition. If current gas composition deviates from the calibration state, measuring deviation can be high. In particular, fluctuating hydrogen components in the gas stream shift the measurement signal substantially.

An acceptable accuracy of gas flow measurement can be achieved by combining the thermal sensor (optionally with 8-digit integrated display) with a thermal conductivity sensor. With the help of the second sensor in the steady flow area, the hydrogen concentration in the gas can be determined approximately, which is read via a 4-20 mA signal into the electronics of the thermal sensor. The flow reading is corrected accordingly. The gas quantity measuring system COMBIMASS® syngas is a device combination in intermediate flange version.

Combining the COMBIMASS® eco thermal sensor with a COMBIMASS® GA-syngas analyzer, which analyzes the individual components of the gas, can significantly improve the accuracy of gas flow determination because the influence of each gas component on the volume signal is known.