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

Abstract

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.

Keywords

• Biogas production
• Chaos
• Mechanical mixing
• Speed control

References

1. Boesinger C, Le Guer Y, Mory M. 2005. Experimental study of reactive chaotic flows in tubular reactors. AIChE J, 51(8): 2122-2132.
2. Demirsoy MS, El Naser YH, Sarıkaya MS, Peker NY, Kutlu M. 2024. Development of elbow rehabilitation device with iterative learning control and internet of things. Turk J Eng, 8(2): 370-379.
3. Gbadeyan OJ, Muthivhi J, Linganiso LZ, Deenadayalu N, Alabi OO. 2024. Biogas production and techno‐economic feasibility studies of setting up household biogas technology in Africa: A critical review. Energy Sci Eng, 12(10): 4788-4806.
4. Hamida El Naser Y, Karayel D. 2024. Modeling the effects of external oscillations on mucus clearance in obstructed airways. Biomech Model Mechanobiol, 23(1): 335-348.
5. Kabeyi MJB, Olanrewaju O. 2022. Optimum biodigestor design and operations. In: Fifth European Conference on Industrial Engineering and Operations Management, July 26-28, Rome, Italy, pp: 424.
6. Kalayci O, Pehlivan I, Akgul A, Coskun S, Kurt E. 2021. A new chaotic mixer design based on the Delta robot and its experimental studies. Math Probl Eng, 2021(1): 6615856.
7. Kapłan M, Klimek K, Syrotyuk S, Konieczny R, Jura B, Smoliński A, Wałowski G. 2021. Raw biogas desulphurization using the adsorption-absorption technique for a pilot production of agricultural biogas from pig slurry in Poland. Energies, 14(18): 5929.
8. Kashfi ME, Kouhikamali R, Khayati G. 2021. The effect of mixing rate on performance of anaerobic reactor in methane production. Iran J Energy Environ, 12(3): 209-219.

9. Lemmer A, Naegele HJ, Sondermann J. 2013. How efficient are agitators in biogas digesters? Determination of the efficiency of submersible motor mixers and incline agitators by measuring nutrient distribution in full-scale agricultural biogas digesters. Energies, 6(12): 6255-6273.
10. Mahmoodi-Eshkaftaki M, Rahmanian-Koushkaki H. 2022. Multi-objective optimization of pneumatic mixing systems for anaerobic digesters: A hybrid technique of statistical modeling and numerical simulations. Waste Biomass Valoriz, 13(6): 2815-2830.
11. Martí-Herrero J, Alvarez R, Rojas MR, Aliaga L, Céspedes R, Carbonell J. 2014. Improvement through low cost biofilm carrier in anaerobic tubular digestion in cold climate regions. Bioresour Technol, 167: 87-93.
12. Mousa H, Obaidat A, Khaled HB, Alawaneh A, Tarawneh A. 2016. Experimental investigation of biogas production from kitchen waste mixed with chicken manure. J Eng Res, 13(2): 115-123.
13. Obileke K, Mamphweli S, Meyer EL, Makaka G, Nwokolo N. 2020. Design and fabrication of a plastic biogas digester for the production of biogas from cow dung. J Eng, 2020(1): 1848714.
14. Obileke K, Onyeaka H, Nwokolo N. 2021. Materials for the design and construction of household biogas digesters for biogas production: A review. Int J Energy Res, 45(3): 3761-3779.
15. Rajendran K, Aslanzadeh S, Taherzadeh MJ. 2012. Household biogas digesters A review. Energies, 5(8): 2911-2942.
16. Sarıkaya MS, Hamida El Naser Y, Kaçar S, Yazıcı İ, Derdiyok A. 2024. Chaotic-based improved Henry gas solubility optimization algorithm: Application to electric motor control. Symmetry, 16(11): 1435.
17. Sebayuana K, Nindhia TGT, Surata IW, Nindhia TS, Shukla SK, Khanal SK. 2021. Performance of 500-liter stainless steel portable biogas anaerobic digester with agitator designed for the tropical developing country. Key Eng Mater, 877: 160-165.
18. Shapovalov YB, Salavor OM, Yakymenko IL. 2023. The economic potential of enhanced method of anaerobic fermentation with green ammonia production for European energy market. In: IOP Conference Series: Earth and Environmental Science, October, 20, Online, pp: 012025.
19. Singh B, Kovács KL, Bagi Z, Nyári J, Szepesi GL, Petrik M, Szamosi Z. 2021. Enhancing efficiency of anaerobic digestion by optimization of mixing regimes using helical ribbon impeller. Fermentation, 7(4): 251.
20. Singh B, Singh N, Čonka Z, Kolcun M, Siménfalvi Z, Péter Z, Szamosi Z. 2021. Critical analysis of methods adopted for evaluation of mixing efficiency in an anaerobic digester. Sustainability, 13(12): 6668.
21. Spodoba MO, Zablodskiy MM. 2021. Залежність енергетичних витрат від типу використаної механічної мішалки у біогазовому реакторі. Electr Eng Power Eng, (1): 26-33.
22. TabkhPaz M, Mahmoodi M, Arjmand M, Sundararaj U, Chu J, Park SS. 2015. Investigation of chaotic mixing for MWCNT/polymer composites. Macromol Mater Eng, 300(5): 482-496.