The Pyrolysis Characteristics Of The Urban Sewage Sludge Pyrolysis Experimental Research

The problem of sewage sludge in domestic city is serious and pressing to the rapidly and healthy development of the city. Every country in the world is seeking for perfect approach of treatment about sludge. In the past, the sewage sludge is regarded as waste, but now people discovered that sewage sludge is a kind of resource. Once it is reasonable handled the foreground of sewage sludge is more clear and have practical significative. Through the pyrolysis properties and low-temperature pyrolysis experiments of sewage sludge which is treated by the Fourth sewage dispose factory of KunMing, the authored detailedly analysised pyorlysis properties and low-temperature pyrolysis of municipal sewage sludge, and did experiments study under different conditions.First of all ,the author introduced the origin , characteristic, imperil, categorize and the instances of treatment and disposal overseas, and detailedly introduced the new and old technologies of treatment and disposal about sludge. Via the argumentations, the author putted forward that the low-temperature pyrolysis of sludge is an important and developmental potential new technology.Secondly the pyroperties of municipal sewage sludge has been done, and it is one of emphases in the article. It includes proximate analysis, ultimate analysis, quantity of heat, DTG-DSC analysis.From the proximate analysis of sludge, we can get that: in the sludge, the content of M_ar is 85.16%; the content of M_ad is 12.35%; the content of A_ad is 37.23%; the content of V_ad is 42.35% and the content of FC_ad is 8.07%. So we can the conclusion that sludge is a fuel which has high content of water, high content of volatile and low content of fixed char.The results of ultimate analysis are: the content of C is 23.70%; the content of O is 27.71%; the content of H is 3.85%; the content of N is 4.76%; the content of 5 is 0.86%;the content of F_e is 3.47%; the content of C_a is 1.87% and the content of P is 1.34% and so on. We can see that the content of C and O arehigh in the sludge, and the others is low, but the content of heavy metal is cannot ignored.From the measure of calorifacient quantity of sludge we can get that the quantity of heat is 8.65kJ/kg. So we can determinant that sludge is a kind of low quantity of heat fuel.The thermograving is an important measure through which can research the pyroperties and mechanism of sludge pyrolysis. There are three weightlessness phases in the process of pyrogenation. Which are 150³60°C , 360⁴85°C , 660 735 °C, and they corresponding three radiative apexes. The former two are the phases of volatile separating out, and the third one is the phase of fixed carbon burning.Combining the TGA analysis we get the living energy and frequency factor : E=29.85kJ/moL A= 50.38mm-1.At last, we have done the experiments in different conditions. It includes different pyrogenation end temperature ^ different reaction times and different content of water. The higher pyrogenation end temperature is propitious to creating of oil; while the creating of char is descend with the ascending of pyrogenation end temperature.For reaction time, there is a balanceable turning point. Before or after the balanceable turning point, the produce rate of the oil and the char is not achieving maximal. Only close the time of balanceable turning point, the produce rate of the oil and the char is maximal; The different of content rate of water has nothing impact to the result of the low-temperature, but it effects the reaction time of pyrolysis directly: the higher content rate of water the long reaction time, the low content of water the short reaction time.The content of water is a pivotal content which affects the balance of energy about sludge low-temperature pyrolysis. But because of the limit of the experimental condition we did not measure the turning point of sludge water content rate.