Application Of Concentration Wave Propagation Model In Dry Anaerobic Digestion Of Corn Stover

Based on concentration wave propagation model, model coefficients suitable forsolid-state anaerobic digestion of corn stover were solved out though the use of softwareMATLAB7.0. The model was fitted and validated with the measured data and the resultshowed that matrix characteristics of the solid-state anaerobic digestion of corn stover canbe mathematically simulated using the model. Heat transfer process of solid-stateanaerobic digester was analyzed and a heat transfer model was build. A real-timetemperature monitoring system for temperature acquisition was built and the real-timemonitoring of temperature for the solid state anaerobic digestion system was achieved. Thedetails are as follows:1. Solid-state anaerobic digestion of corn stover was carried out with the initialmoisture content of70%in12reactors (8L,145mm) at37°C. Reactors were taken out onday2,4,6,8,10,12,15,18,21,24,27and30for analysis, respectively. The matrix wassampled by12layers from top to bottom of the reactor. TS, VS, methanogens and VFAconcentration in the sampled matrix were analyzed. According to experimental data, modelcoefficients of concentration wave propagation model were solved out. The modelcoefficients obtained with the initial moister content of70%were fitted with that with theinitial moisture content of75%,80%and85%and the results showed that the modelcoefficients in fit well with the moisture content in the range of70%-80%.2. DS, DBand ρm, the diffusion coefficient of the concentration wave propagationmodel, were modified using pdepe differential function in MATLAB toolbox. Combinedwith numerical integration, numerical solutions of VS, VFA and methanogensconcentration in the solid-state anaerobic digestion of corn stover were solved. Thenumerical solutions were fitted with the experimental measured value and the resultsshowed that: with the initial moisture content in the range of70%-80%, changes of VS,VFA and methanogens concentration in the solid-state anaerobic digestion of corn stovercould be accurately predicted using the solved concentration wave propagation model.Thechanges in the early and mid-digestion of corn stover could be accurately predicted using the model by dividing three parts of digestion，while there were a difference in the latedigestion.3. A temperature monitoring system for solid-state anaerobic digestion of corn stoverwas set up. Using the system, temperature data of the matrix could be automatic collectedand displayed and recorded in real time via wireless transmission. A heat transfer modelwas establish and verified by experimental monitoring data. The temperature monitoringsystem and heat transfer model might provide some technical support for the insulationdesign of a reactor.