| It has been the most urgent problem how could be disposal and utilization of municipal domestic sludge in china, especially high moisture content. Currently, With the increasing amount of sewage sludge produced in China. Annual emissions of sewage sludge (moisture weight percentage) growth rate of greater than10%. traditional treatment and disposal methods for sludge must reduce its volume for its utilization as resources firstly. It is typical energy consumption of the sludge-drying, a part of the water could be filter out in high pressure process, in order to reduce the energy consumption, solar energy and reclaimed water heat pump drying technology included energy of Solar and reclaimed water Combined with heat pump technology organically, by Means of the solar energy, reclaimed water and heat pump provide thermal energy for drying. Through the Solar Energy and Reclaimed Water with Double High-temperature Heat Source, the sludge would significantly reduce the moisture content in drying process, significantly cost reduction, to achieve the goal of energy conservation and emissions reductionFirstly dehydration by high pressure, taking both dewatering effect and cost-effectiveness into account, the sludge filtration pressure is controlled from13MPa to15MPa, filter-pressing period of20min, and the moisture content decreased to54%after dewatering by plate-frame pressure filtration finally. The experiment of sludge conditioning and filter-pressing results show that:lime and FeCl3united for sludge on conditioning, the sludge resistance decreased obviously. When the lime dosage was20g/kg (DS), ferric chloride was200mg/L, the dewatered sludge was observed by electron microscopy (SEM). Could find the floc structure and the stability of sludge colloidal particles were destroyed. The surface of sludge attached water was removed, therefore, the sludge dewater ability achieves best.Secondly, solar and reclaimed water as heating heat source, the solar energy and air source heat pump was the main heating source, when the heat is insufficient, reclaimed water heat pump was turned on as energy supplementary, aim to make the drying system perfect, which could run normally under different environment conditions, ensure heat pump system of double heat source would produce sufficient hot air (>70℃) for drying chamber, after the drying process, moisture content (MC) of sewage was shrunk from60%to40%.According to the basis of parameter analysis about weather in Kunming, and the law of conservation of mass and the law of conservation of energy, energy balance equation and mass balance equation the energy about the solar energy heat-collecting system and drying chamber were derived. Considering the technical index of main structure components, and adding effect of hot-air drying experiment in the laboratory, the best condition was attained: hot-air temperature of70～85℃, thickness was20nm, so we could ensure the main technical target and specification of equipment for system. In the Xundian county sewage treatment plant, according to monitoring statistics such as air flow, temperature and electricity consumption etc. On sunny day, under the condition which total ventilation was certain, improve ventilation of solar collector, not only make the total heat quantity of system increased, and also improve the COP of system; with the increasing of outside air temperature, the COP decreased slightly from4.6to4.4when the heat pump ran separately, the whole system COP maintained above3.7.Combined high pressure filter and Solar Energy and Reclaimed Water Heat Pump, the treatment cost could be lower than￥60per ton, and soldAll the above analysis shows that the way brought environmental, economic and social benefits, which would help to set a paradigm for resource disposal and comprehensive utilization of Sludge... |
PDF Full Text Request