This paper introduces a new-type of antigravity mixing method, which was applied in the biogas production process, using organic wastewater fermentation. It was found that the digesters with two designs, a highposition, centralized pressure outlet and a high-position, dispersed pressure outlets, both lead to an increase in biogas production rates by 89% and 125%, respectively. The biogas production peak appeared 1 day and 7 days earlier, and the COD removal rates were raised by 27% and 42%, respectively. The results indicated that the optimized flow field had a significant impact. This work also explains the mechanism of flow field optimization using computational fluid dynamics (CFD) software for the simulation of the flow field form in the hydraulic mixing.

Thermogravimetric analyses of Pinus sylvestris from Xinxiang were performed to investigate its kinetic characteristics, which could provide information for industrial applications. Thermal degradation experiments were conducted at various heating rates of 10 °C/min, 20 °C/min, and 60 °C/min using a thermogravimetric analysis-differential scanning calorimetry (TG-DSC) analyzer with an inert environment. The peak pyrolysis temperatures of the three major components (hemicellulose, cellulose, and lignin) were predicted by the Kissinger-Kai method, and activation energy values (Eα) were calculated. The Eα of Pinus sylvestris was also estimated by two model-free methods. The decomposition reactions of hemicellulose, cellulose, and lignin at different temperatures were the main reason for fluctuations in Eα. The time for heat transfer was less sufficient at a high heating rate compared with that at a low heating rate, which caused the temperature gradients in the samples. Therefore, the temperature of maximum exothermic peaks was higher than the maximum pyrolysis temperature. This kinetic study could be useful for providing guidance for optimizing the biomass pyrolysis process.

Pharmaceutical wastewater is a kind of high-hazardous waste. To realize non-waste production, experiment and computational fluid dynamics (CFD) simulation were performed to reveal the hydraulic mechanism of mixing modes. Three digesters, numbered 0# (no-port), 1# (one-port), and 4# (four-port), were conducted by dextran pharmaceutical wastewater. Digester 0# is the control group without mixing. Mixing mode of bottom inlet and high-position outlet is employed to 1# and 4#, the outlets of 1# and 4# are centralized outlet with only one port and distributed outlets with four ports, respectively. Experiment result shows the daily biogas production of 1# and 4# are 45% and 58% higher than 0#, and the pollutants removal rate increased 20% and 24%, respectively. CFD simulation shows the second phase (dextran wastewater) of 4# failing to form a complete hydraulic path like the first phase (water), which explain the mixing modes can greatly improve the biogas yield, but the fourport mode has a weaker advantage than the one-port.