Microcontroller based logic control system for automated novel paddy straw bale combustor technology applied to greenhouse heating

Abstract

Automation of paddy straw bale combustor technology was achieved by designing a microcontroller based logic control system for controlling bale feeding, ensuring complete combustion of paddy straw bale and cleaning of the grate by removing bottom ash. The system generates flue gas at 350 °C to maintain greenhouse air temperature 10 °C higher (for 24 h continuous operation) than ambient air during winter months for Ludhiana climate (30.56 °N), India. The microcontroller controls the automatic opening of the furnace door, conveyor speed for forward bale speed by motorized operation of chain and sprocket mechanism attached to the door, door closing and opening for specified time, grate shaker with comber driven by 0.5 hp motor actuated by microcontroller and operated by a worm gear.A microcontroller controlled panel was designed with six preset values of small amount of fuel delivery by each injector onto the bale for complete combustion. The resonant circuit was provided with the help of a crystal, X1 10 Mhz and C4, C5 capacitors to get accurate timing calculations in each operation in milliseconds as used in the circuit. The compatible microcontroller used for the purpose was AT89C2051 as it matched with the desired operational parameters at low cost. It was observed that the developed microcontroller based logic control system could achieve the desired operations of bale feeding, fuel injection and grate cleaning at >98% efficiency.