Study On Low-temperature Pyrolysis Of Municipal Solid Waste And Sludge

In urban China, the waste generation rates in major Chinese city are increasing.The main component of which is organic matter, thus making them a predominantlyrenewable energy source. During the exploration for many years, low temperaturepyrolysis is considered as more advantages and a huge potential.Pyrolysis experiments of the mixtures from nine different combustibles in MSW(municipal solid waste) and sludge have been performed in the laboratory scalereactor under nitrogen atmospheres. All runs were carried out at 300℃-700℃. In thepaper, different behaviors of the pyrolysis also have been investigated and compared.The results indicate:In the process of MSW, volatile contents decrease and fixed carbon and ashcontents increase with the increasing pyrolysis temperature. In the initial temperaturestage, volatiles vary quickly from 53.06% at 300℃ to 11.96% at 550℃, heating valuedecreases slowly with the rising FPT(final pyrolysis temperature). In addition,ignition temperature increases with the rising temperature and quickly varies attemperatures below 400℃. Compared to MSW, bulk density for solid residue is 2.1times more than that of MSW, heating value of per volume is about 6 times more thanthat of MSW. It is also shown that characteristic of solid fuel obtained from MSWpyrolysis is improved, and volume of MSW is greatly lessened and heating value involume as well as ignition temperature increase, which is profitable to reducing costsin combusting and to storage and safety.In the process of sludge: With the rising of FPT, solid residues gradually lowdown, accounting for 89%-73.5% of net sludge, which easily are stored longer,totalgas volume and max gas rate rise. The max gas rate for sludge range from1.5L/(g·min)to 4.8 L/(g·min) at the temperature ranges 300℃-500℃, occurring within 10-25minat the beginning of pyrolysis. The tendency of max gas rate is basicly same indifferent FPT, which shows that the gas rate quickly reaches max value in short time,then dropping slowly, up to the end of reaction,therefore, which provide basic andtrue date for real application of engineering about low-temperature pyrolysis ofsludge .