Pyrolysis Polygeneration Technology Of Municipal Wastewater Sewage Sludge

This thesis was aimed to investigate the controllable process of the high-temperature and low-temperature pyrolysis technology and the resulted pyrolysis products mechanism of sewage sludge.Firstly, based on the method of orthogonal experimental design, eighteen groups of pyrolysis testing were designed, which ran under a varied heating conditions like different higher ending temperature, heating rate, added catalyst. The factors influencing the properties of three-phase pyrolysis products were discussed on the basis of those obtained results, and thus the pyrolysis process of the three-phase products was optimized. Secondly, the gas chromatograph, GC-MS and calorimeter, and heat value analyzer were employed to analyze and compare the characteristics of the three-phase products derived from18groups of sewage pyrolysis tests under the high-temperature and low-temperature conditions.Finally, on the basis of the law of energy conservation the thermal process of the sludge pyrolysis to produce thress-phase products was analyzed. In addition, reaction dynamics mechanism of the sludge pyrolysis was also discussed. All the obtained experimental results indicated some significant conclusions as follows:1. Form the total heating value and the yield of pyrolysis products, it can be noted that sludge pyrolysis to produce hydrogen-rich gas under lower temperature and sludge pyrolysis to produce bio-oil under higher temperature condition have more advantages. At550℃of the reaction temperature, heating value and the yield of the bio-oil is highest. At850℃of the reaction temperature, heating value and the yield of the hydrogen-rich gas is highest.2. The obtained bio-oil and hydrogen-rich gas are very complex in their chemical compositions. The ending temperature give the most evident impact on chemical characteristics of liquid-gas products, and the heating rate has a decreased impact. Residence time has the minimum influence. The used catalysts also have obvious influences on field and heating value of gas and liquid products, but little influence on the obtained solid products.3. Analysis can be seen from the energy balance, the energy consumption in the process of sludge pyrolysis is closed connected with the selected pyrolysis conditions choose.It can be seen that sludge drying and employing a low temperature condition can contribute to increase energy consumption ratio and the recovery rate.4. Sludge pyrolysis process is a two-serial competitive reaction process. Heating rate and the added catalyst have a significant impact on sludge conversion rate, the maximum weight loss rate, volatile matter precipitates temperature characteristic parameters.