| Industrial wastewater and sewage sludge generated increasing with the rapid development of the city,and because internal sludge biomass ratio and moisture content is higher,is likely to cause pollution of the environment,processing becomes the key problem about them.Sludge drying is one of the important methods of excess sludge reduction processing,and bio-drying generate heat with their own biomass,thereby discharging the water,there is a new technology has broad prospects of sludge treatment.In this paper,a continuous bio-drying reactor is designed,the purpose is to make the sludge drying to the level of economic dry solids content,so that the sludge can be economical and safe combustion in the boiler to recover energy.In all the tests,the sludge dry solids content have reached the economic level.In bio-drying process,in addition to forced ventilation,the sludge drying rate can increase through the heat from activity of the mesophiles and the thermophiles,and these microorganisms naturally present in the sludge of the porous medium,which makes bio-drying process due to having an internal heat source than conventional drying technology advantage.To optimize biological sludge drying technology,improve its efficiency,with the help of simulation software COMSOL numerical simulation to the pile body in the biological sludge drying process,to simulate the internal temperature and is compared with the experimental value,in order to study internal heat and mass transfer characteristics of the sludge.By studying the existing literature,this paper analysis the play a key role in the process of biological sludge drying variables,such as residence time,ventilation rate,ventilation,temperature and relative humidity,etc.In this paper,in order to identify what we establish the applicability and accuracy of 2-D model,we through the adjustment of the key variables,determine the four groups of experiment conditions of different experiment scheme.First of all,by determning condition of experiment,four groups of experiments and the experiment of sludge in the process of temperature,sludge moisture content,and import and export air temperature and humidity measurement,in order to facilitate analysis,we will be the whole experiment is divided into four stages,each stage for a quarter of the overall retention time,after the experiment,the result of the experiment were analyzed,and the major of biological drying process validated whether the quality of the water balance,if the balance,we experiment data with reliability,secondly,using the software COMSOL to sludge drying pile body 2-Dmodel,simulate the temperature distribution of the pile body internal biological,through to the numerical and experimental simulation numerical comparison,analysis of sludge drying in the process of matrix movement regularity of the internal heat and moisture.Experiment and simulation results of this article a few theoretical analysis results applied to the analysis,the actual drying process of sludge dryiing process to realize optimization design and optimal operation has important reference value. |
