Investigation of the optimal operating temperature and thermal shock effects in a mesophilic biogas reactor with a static vibratory mixer
摘要
The research was conducted in a horizontal oscillating bioreactor with a working volume of 1000 liters and a headspace of 400 liters, located in the Urgench district of the Khorezm region, Republic of Uzbekistan (41.626921° N, 60.607069° E) from 28.06.2024 to 02.09.2024. Special mixing blades were installed on the inner surface of the reactor. The reactor’s mixing system utilizes an oscillating motion based on a 30° angle, mounted on a specialized arc-shaped platform. The process was carried out under completely natural ambient conditions. The average moisture content of the loaded substrate was 76 ± 2.6%, and it was fed into the reactor twice daily at an organic loading rate (OLR) of 1.26 kgVS·m⁻3·day⁻1. The moisture content was increased to 90–92% by adding 5 liters of water for every 4 kg of substrate. After a hydraulic retention time (HRT) of 50 days, the system reached a steady state, with the daily effluent discharge equal to the amount of substrate loaded." The analysis revealed that the produced biogas contained an average methane content of 54 ± 10%. The total cumulative biogas production amounted to 13.626 m3, which is equivalent to 490.5 MJ of thermal energy. The optimal operating temperature for the biogas reactor was determined to be 37.2 °C using polynomial regression and 36.957 °C according to the Arrhenius-Hinshelwood regression model. Upon studying the distribution of biogas production in relation to temperature fluctuations, the thermal shock threshold for the microorganisms participating in the bioprocess was identified as 4.672 °C. Furthermore, the article evaluates the compatibility and reliability of the experimental results obtained from the bioreactor with a static oscillating mixer against Anaerobic Digestion Model No. 1 (ADM1) and previously proposed regression equations.