Research On Temperature Field Variation And Simulation Of Dry Anaerobic Fermentation Reactor

Energy shortage is already a major problem facing our country.To develop and utilize renewable clean energy including biomass energy is one of the important challenges in the new century.In China,300 million tons of straw are discarded every year or burned in situ.The annual output of livestock and poultry manure is about 3.8 billion tons,and more than 40%of them have not been effectively used,causing serious environmental pollution and waste of resources.Anaerobic fermentation technology is one of the most important ways to realize the energy utilization of agricultural waste.It has the features of clean production process and low operating cost.Dry anaerobic fermentation technology can generate low-energy energy and produce less sludge.Biogas,a.renewable clean energy source and biogas residue,can be composted or used to produce soil amendments.Through the analysis of the research status of anaerobic fermentation technology at home and abroad,a major problem in the dry fermentation technology is the problem of mass transfer and heat transfer in the reactor,which restricts the popularization and application of dry anaerobic fermentation technology.Based on the review of anaerobic fermentation technology and system research at home and abroad,this study uses straw,animal manure and other agricultural organic wastes as raw materials.Through theoretical research,experimental analysis,and simulation,sequencing batch anaerobic dry methods are performed.The design and experimental study of the fermentation test platform analyzes the test results and process parameters.The main research work is as follows:(1)Under certain initial conditions,dry anaerobic fermentation experiments using dry corn stalks and fresh cow dung as raw materials were conducted.The results showed that the test platform was operating normally and the gas production was stable.The average gas production per day reached 37.55L,the average volumetric gas production rate was 0.83L/(L d),and the unit dry matter production gas volume was 151L.(2)Relying on the designed dry anaerobic fermentation test platform to test the temperature change during the dry anaerobic fermentation of the mixed substrate during the temperature increase at 40? and 45?.According to the test results,the heating conditions should be given priority.For 40? temperature conditions.At the same time,relying on the dry anaerobic fermentation platform,between the solids content of 25%and the solid content of 20%,preference can be given to the fermentation conditions where the mixed fermentation substrate contains 15%solids.(3)The cow manure-straw mixed raw material system was used as a "quasi-fluid",and the discrete solid particles were regarded as a virtual continuous phase fluid.Using Fluent to conduct simulation studies to establish a numerical simulation model of the temperature field.The established simulation model results are consistent with the actual experimental data to a certain extent,and the error range is within 20%.Therefore,Fluent has a great role in guiding the entire fermentation process.