Application And Correction Of ADM1 And CFD In Anaerobic Digestion To Produce Methane

Anaerobic digestion No.1 mathematical model(ADM1)is a kinetic model used to describe biochemical processes and physicochemical processes of anaerobic digestion.It has functions such as fitting of changes in system substance concentration during anaerobic digestion and prediction of reaction results.Computational Fluid Dynamics(CFD)is a research method used to describe the flow trajectory equation of a fluid flow process and the physical quantity calculation of a fluid flow process.In the study of this paper,the anaerobic digestion reaction system was partially modified and added based on ADM1.At the same time,the CFD research method was used to simulate the flow condition of the anaerobic digestion flow field system,which provided theoretical basis for the full mixed flow field used by ADM1.The main research contents in this paper are as follows:(1)In the process of methane production under the inhibition of ammonia nitrogen,the flow field distribution simulation results show that the reaction system is a full mixed flow field,which is in line with the preconditions for the use of ADM1.The simulation of the reaction system was first carried out using the original ADM1.In the simulation results,the goodness of fit of the propionic acid concentration value and the butyric acid concentration value was low(the goodness of the propionic acid concentration value was 0.13,and the goodness of the butyric acid concentration value was 0.02).At the same time,a description of the valeric acid component is lacking.Therefore,the model has been modified and added.Model A was used to add ADM1 with acetic acid inhibition,ADM1 with valerate production,and ADM1 with acetic acid inhibition and valerate production.The results showed that ADM1 with acetic acid inhibition was added for propionic acid and butyric acid.The goodness of fit was improved(the goodness of the propionic acid concentration value was 0.97,and the goodness of the butyric acid concentration value was 0.2),but the description of the valeric acid component was still lacking.ADM1,which is a valerate-forming term,is described for the valeric acid component,but its goodness of fit is low.(The goodness of fit for propionic acid concentration value is 0.11,the goodness of fit for butyric acid concentration value is 0.02,and the goodness of fit for valeric acid concentration value is 0.01).At the same time,ADMI with the addition of acetic acid inhibition and valerate production has a good fitting result for the carbohydrate methane production under the inhibition of ammonia nitrogen(2)High ammonia nitrogen(4000mg/L NH4+-N)system has obvious inhibitory effect on carbohydrate methanogenesis.In this paper,it is chosen to add bio-enhanced bacteria(Methanosarcina barker ? bacteria(hereinafter referred to as MSC),Methanobrevibacter smith ? bacteria(hereinafter referred to as MBB),Syntrphaceticus schik ? bacteria(hereinafter referred to as S),Tepianaerobacter acetatoxydans bacteria(hereinafter referred to as T),which can be very Goodly restore the inhibitory effect of high ammonia nitrogen system on carbohydrate methanogenesis.In order to more conveniently study the synergistic and antagonistic effects of the biofortification process on the reaction system.Based on ADMI,this paper uses three model methods(method for debugging kmac parameters(hereinafter referred to as KM method),method for debugging ksac parameters(hereinafter referred to as KS method),method for debugging KINH3,and Xac parameters(hereinafter referred to as KI method).Fitting.The results show that the method of debugging kmac parameters has the best fitting goodness for the description of bio-enhancement process(the goodness of fit of CH4 is 0.87,the goodness of fit of total volatile fatty acid(TVFA)).It is 0.92).Therefore,the KM method is used to simulate the bio-enhancement in the reaction system,and the simulation results are good,which is in line with the actual situation(3)The anaerobic digestion process of kitchen waste is often due to the large processing load and complex reaction system,which makes the reaction rate of anaerobic digestion process of kitchen waste is slow and the treatment efficiency is low.Therefore,in the digestion process of kitchen waste,the synthesis gas is added to realize the coupling digestion process.On the one hand,the syngas component can promote the stirring of the kitchen waste and accelerate the efficiency of the reaction process.On the other hand,kitchen waste provides a carrier for bacteria and a bacterial nutrient for the start-up phase for syngas digestion.Thereby,the efficiency of the coupling process of the kitchen waste and the syngas is improved.In this paper,the model is fitted to the reaction process based on the original ADM1.For the syngas components not described in ADMI,the modification of the biochemical process of syngas components is made based on the toxicity mechanism of CO and the saturation absorption curve function of CO.Based on the theory of gas-liquid mass transfer double membrane and the principle of molecular transport process,the modification of the physicochemical process of syngas components was made.The modified model provides a good description of the reaction of the kitchen waste decomposition process,the reaction of the synthesis gas methane production process,and the coupling between the two component reactions.