Mathematical modeling of anaerobic digestion is a powerful tool to predict gas yields and optimize the process.The Anaerobic Digestion Model No.1(ADM1)is a widely implemented model for this purpose.However,modeling fu...Mathematical modeling of anaerobic digestion is a powerful tool to predict gas yields and optimize the process.The Anaerobic Digestion Model No.1(ADM1)is a widely implemented model for this purpose.However,modeling full-scale biogas plants is challenging due to the extensive substrate and parameter characterization required.This study describes the modification of the ADM1 through a simplification of individual process phases,characteristic components and required parameters.Consequently,the ability of the simplified model to simulate the co-digestion of grass silage and cattle slurry was evaluated using data from a full-scale biogas plant.The impacts of substrate composition(crude carbohydrate,protein and lipid concentration)and variability of carbohydrate degradability on simulation results were assessed to identify the most influential parameters.Results indicated that the simplified version was able to depict biogas and biomethane production with average model efficiencies,according to the Nash-Sutcliffe efficiency(NSE)coefficient,of 0.70 and 0.67,respectively,and was comparable to the original ADM1(average model efficiencies of 0.71 and 0.63,respectively).The variability of crude carbohydrate,protein and lipid concentration did not significantly impact biogas and biomethane output for the data sets explored.In contrast,carbohydrate degradability seemed to explain much more of the variability in the biogas and methane production.Thus,the application of simplified models provides a reliable basis for the process simulation and optimization of full-scale agricultural biogas plants.展开更多
Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid（VFA） production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid s...Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid（VFA） production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1（ADM1） was modified to simulate the VFA generation in batch, semicontinuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0.Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms,were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the Ksof acetate is 0.025, the km,acis 12.51, and the KI_NH3is 0.02,respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH 10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30 m^3full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation.展开更多
基金the Teagasc Walsh Scholarship Programme(Ireland)(Ref:2021010).The input of Dr.Ciara Beausang and Dr.J J Lenehan in the study concept and design is acknowledged.
文摘Mathematical modeling of anaerobic digestion is a powerful tool to predict gas yields and optimize the process.The Anaerobic Digestion Model No.1(ADM1)is a widely implemented model for this purpose.However,modeling full-scale biogas plants is challenging due to the extensive substrate and parameter characterization required.This study describes the modification of the ADM1 through a simplification of individual process phases,characteristic components and required parameters.Consequently,the ability of the simplified model to simulate the co-digestion of grass silage and cattle slurry was evaluated using data from a full-scale biogas plant.The impacts of substrate composition(crude carbohydrate,protein and lipid concentration)and variability of carbohydrate degradability on simulation results were assessed to identify the most influential parameters.Results indicated that the simplified version was able to depict biogas and biomethane production with average model efficiencies,according to the Nash-Sutcliffe efficiency(NSE)coefficient,of 0.70 and 0.67,respectively,and was comparable to the original ADM1(average model efficiencies of 0.71 and 0.63,respectively).The variability of crude carbohydrate,protein and lipid concentration did not significantly impact biogas and biomethane output for the data sets explored.In contrast,carbohydrate degradability seemed to explain much more of the variability in the biogas and methane production.Thus,the application of simplified models provides a reliable basis for the process simulation and optimization of full-scale agricultural biogas plants.
基金supported by the Joint Innovative R&D Program of University and Industry(No.BY2014023-03)National Key Technology R&D Program of the Ministry of Scienceand Technology(No.2014BAD24B03-02)
文摘Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid（VFA） production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1（ADM1） was modified to simulate the VFA generation in batch, semicontinuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0.Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms,were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the Ksof acetate is 0.025, the km,acis 12.51, and the KI_NH3is 0.02,respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH 10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30 m^3full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation.
