MEMS-based electronic nose system for measurement of industrial gases with drift correction methodology

Abstract

This work explores the use of microelectromechanical system (MEMS) sensors in electronic nose systems for the measurement of prominent industrial pollutants and proposes a methodology for the correction of drift induced in sensors during prolonged use for measurement of corrosive compounds. MEMS sensors have the advantages of low recovery and response time, lower power consumption and improved sensitivity. An electronic nose system is developed to quantify the four major pollutants emitted from various process industries, i.e. hydrogen sulfide (H2S), carbon monoxide (CO), ammonia (NH3) and ethanol (C2H5OH). All four pollutants represent major environmental and human health hazards and rapid quantification is vital. A drift correction algorithm was developed using experimental design and robust regression to correct the drift induced in the sensors. The experiments consisted of eight experimental sets with mixtures of H2S, CO, NH3 and C2H5OH measured on the same sensor array at the start and after a gap of 1 year. The methodology consisted of mapping the response of sensors after 1 year compared with that observed at the very start (day 1) of the experiment. The results showed successful implementation of the methodology, with the root mean square error values being significantly reduced at 0.235, 0.354, 0.145 and 0.651, respectively, for the four studied odorants (H2S, NH3, CO, and C2H5OH).