Perancangan dan Pengujian Prototype Syngas Analyzer dengan Mekanisme Pengaturan Laju Aliran dan Pengenceran Gas Menggunakan Sensor MQ Series

Abstract

Indonesia is one of the world's largest coffee producers, generating substantial coffee husk waste with the potential to serve as biomass feedstock for gasification, producing syngas composed of H₂, CO, CH₄, and CO₂. Measuring syngas composition requires a syngas analyzer; however, previous studies' sampling systems lacked adequate flow rate regulation, gas mixing, and dilution mechanisms, resulting in fluctuating MQ-series sensor readings. This study designed, built, and tested a syngas analyzer equipped with a motorized air flow mechanism to regulate air and syngas flow rates, a baffled mixing chamber with a pneumatic vacuum valve for gas dilution and sampling, and MQ-4, MQ-7, MQ-8, and MQ-135 sensors for syngas concentration readings. The research method comprised design, fabrication, assembly, and performance testing of each subsystem. Test results showed the flow regulation mechanism achieved an air flow rate of approximately 30 LPM and a syngas flow rate of approximately 0.3 LPM, maintaining a consistent 1:100 dilution ratio. The mixing chamber produced more better gas mixing and continuously drew syngas into the measurement chamber. Testing across a gasification temperature range of 200–360.2°C showed H₂ levels rising from 1% to 2%, CO from 2% to 8%, while CH₄ decreased from 28% to 16% and CO₂ from 26% to 5%. All subsystems operated leak-free (Qin ≈ Qout), and sensor readings demonstrated good repeatability. The developed syngas analyzer thus produces representative measurement data supporting the characterization of syngas from coffee husk biomass gasification.