Design And Research Of Solar Heat Pipes Drying Sludge System

In recent years,the technology of sludge drying has developed rapidly,while the technology of sludge drying with solar energy has not yet matured.Using solar energy heat pipe technology can improve the utilization of solar energy.It is of great significance to develop efficient and low cost sludge drying technology.This paper aims to complete the preliminary design of the drying mud sand system of the solar heat pipe and the research of the drying simulation test of the mud sand heat pipe.Based on the basic theory of solar energy drying,the design and calculation method of solar heat pipe drying sludge is put forward based on the relationship of balance between material and energy in the drying process of mud and sand,and a drying system with a daily drying capacity of 14 tons was initially designed.In order to study the mechanism and characteristics of the double-side heating and drying of solar heat pipe,a simulation test system was designed and built.An orthogonal design method was used to complete the test and analysis of the results which affected by the drying rate of multiple factors.The main contents and results of the paper are as follows:(1)Heat and mass transfer characteristics during sludge drying and research on factors affecting sludge drying.The mathematical model of the evaporation of sludge drying moisture was established and the factors affecting evaporation were analyzed.The results shows that increasing drying medium temperature can effectively increase sludge drying rate.(2)According to the conservation of the energy of the sludge drying in the greenhouse,the design and calculation of the solar heat pipe drying system was completed.Based on the annual amount of dry sludge,under the premise of energy conservation in the greenhouse,through the analysis of the drying capacity in the greenhouse and the influence of the setting of basic parameters on its balance,the determination of the main dimensions of the system and the loss of the energy of indoor maintenance structure were completed,besides,the sizes and types of heat pipe were selected.(3)Through the thermal calculation of the solar drying equipment,the preliminary design of the solar heat pipe drying sludge system was completed,and the size and main relevant components of the solar heat pipe drying apparatus were determined.(4)According to similar theories,the design and construction of a solar drying simulation test platform was completed.The effects of irradiation intensity,thickness,time,and heating temperature on sludge drying and whether there is interaction between factors were studied by the methods of orthogonal design test.Finally,through the comparison of energy consumption,it is concluded that the heating effect of double side heating is better than that of single side irradiation under the condition of the same total power consumption.Under the same conditions,the moisture content can be reduced by 1%-4%.