Design of a Chaotic Speed-Controlled Mixing Device and Efficiency Analysis in Biogas

This study investigates the impact of chaotic speed-controlled mixing on biogas production efficiency and compares it with conventional fixed-speed mixing. Traditional mixing methods, often operated at fixed speeds or continuous modes, lead to high energy consumption and microbial instability. To address this, a hybrid mixing system combining a helical and propeller shaft was designed to enhance substrate homogenization and biochemical reaction efficiency. A Programmable Logic Controller (PLC) was integrated for automatic process control, while chaotic mixing algorithms, based on Hadley, Halvorsen, Lorenz, and Sprott-A systems, dynamically adjusted the mixing speed to optimize performance. Experiments were conducted at 20°C and 30°C under controlled laboratory conditions. Results showed that chaotic mixing significantly improved methane yield and combustion duration compared to fixed-speed mixing. At 20°C, the Chaotic Sprott-A method produced 18 L/day of methane, compared to 16 L/day with fixed-speed mixing. At 30°C, the Sprott-A method reached 22 L/day, surpassing the 20 L/day of the fixed-speed method. Additionally, combustion duration, an indicator of biogas quality, increased from 740 seconds (fixed-speed) to 829 seconds (Chaotic Sprott-A). These findings confirm that chaotic mixing enhances substrate distribution, improves biochemical reaction efficiency. Chaotic speed-controlled mixing presents a promising alternative for biogas reactors, offering higher methane production.