Low-cost real-time monitoring and automated control system for a bench-scale portable downdraft gasifier

This research work focuses on the development of a real-time monitoring and automated control system with remote access, as well as integrated data collection and storage, for a portable biomass gasification prototype to generate electricity from agricultural waste. The prototype consists of an air-blown downdraft fixed-bed gasifier and a producer gas conditioning unit, which operate together in a remotely controlled ensemble. The proposed system stands out for its compact size, transportability, and low-cost design, making it suitable for implementation in small agricultural facilities, especially in areas where conventional electrification is limited or non-existent. Two preliminary tests were conducted to evaluate the performance of the monitoring system. In the first test, the system achieved a target temperature of 600 $°C$ in less than 20 min and maintained it within a variation range of $\pm 25°C$. After holding this temperature for an hour, the setpoint was raised to 800 $°C$, with the system achieving the new target in less than 10 min. In the second test, a setpoint of 800 $°C$ was reached in 16 min, with an additional 3 min required for stabilization. Both tests, lasting approximately 4 h, consumed a total of 13.43 kg of biomass. The results demonstrate the system’s ability to reach target temperatures in less than 25 min while maintaining stable temperature oscillations. The system’s graphical interface enables intuitive, real-time, and remote monitoring and management of temperatures in several zones along the gasifier’s height. Additionally, the interface allows manual or algorithmic control of the system’s actuators, with the ability to modify the control algorithms through over-the-air updates.