In the frame of my BRISK2 mobility, I have stayed at Department of Energy technology at KTH Royal Institute of Technology. The main purpose of the mobility stay was to conduct experimental investigation in order to confirm previously proposed theoretical concept of the new method of quality measurement of biogas and upgraded biogases. The concept of the method is based on the usage of market available sensors for low costs implementation.

The following equipment was used to conduct an experiment.

  1. Gas-mixing station. That allows to prepare gas mixtures equal to biogas and upgraded biogas.
  2. NDIR and TCD sensor array. Two sensor types were used as measurement equipment: NDIR for the hydrocarbons and CO2 concentrations and TCD for direct measurement of thermal conductivity of the gas mixture.

Gas chromatograph Varian CP4900 for validation of measured experimental data.

My work during these two weeks was divided in three steps. The first step was “engineering”.

This step mainly consisted of equipment adjustment: sensors and chromatograph calibration, chromatograph working temperature and pressure selection, detailed calibration of propane channel of gas-mixing station.

The second step was “experimental”. Gas matrixes were prepared for binary and trinary mixtures with minimal step of 0.5% in order to eliminate the influence of gas-mixing station mixing error. Measurements were held in accordance with gas matrixes.  For binary mixtures, chromatograph readings were taken in parallel for validation of gas mixtures received.

The third step was “analytical”.  This step included finding statistical patterns between calorific value and measured data; comparison of values measured by sensors array and gas chromatograph.

The result of work is successful implementation for experimental investigation and collected data for further processing. After preliminary results analysis it was found out that NDIR sensors did well with measurements on CO2 and CH4selective channels, the direct mixture thermal conductivity measurement sensor has also shown good results.