| With the rapid development of our economy and the acceleration process ofindustrialization, the population aggregated rapidly to urban areas, followed by theenvironmental pollution and energy shortage, seriously impacting on thesustainable development of the city and resident life. It’s urgent to take measure toharmless municipal solid waste. But the waste disposal technology was restrictedby existing techniques, just solving the present problem and leaving pollution to behandled in future. This is a short sighted behavior, and we still have a long way togo. While waste incineration was used to deal with garbage with a good effect, butlimited to the character of waste in our country, unable to achieve good results.Further exploration and attempt are still needed in MSW disposal. Pyrolysistechnology initially used in coal pyrolysis was extended to waste treatment in earlyseventies of last century, which can be widely applied to various composition anddifferent content, recovering energy in form of gas or liquid oil. This technologycan fully make MSW harmless and utilize the garbage resource, having aprospective future. In this paper, organic municipal solid waste was studied bycatalytic pyrolysis of waste treatment technology, giving suggestions for futureMSW disposal.Firstly, the organic municipal solid waste sample was collected from a garbagecollection station and analyzed. The results show that the garbage sample mainlyconsists of kitchen garbage, plastic, paper, fabric and wood, accounti ng for62.96wt%,11.95wt%,8.17wt%,6.4wt%and10.52wt%respectively, with heatingvalue of5279kJ/m3. It can be seen that the main components of the sample werekitchen garbage. Further investigation also has been carried and showed that thekitchen garbage has a high moisture content of65.23%, lower the heat value of thesample, while the plastic and rubber have a moisture content of less than2%. TheTG/DTG analysis of typical organic municipal solid waste component showed thatthe nature of weight loss was depending on the property of itself. The kitchengarbage component has a complex composition and wide weight-loss temperaturewith two mass loss peaks.Secondly, the modified dolomite as the carrier, Ni-Fe/MD, Ni-Cu/MD,Ni-Co/MD, Ni-Ce/MD, Ni-La/MD catalysts were prepared by co-precipitationmethod. The catalyst active component distributed on the surface of the support asa shell-like structure during homogeneous precipitation process with specificsurface area and pore volume. The active components of Ni-Fe/MD catalyst wereNiO and Fe2O3with an uneven surface consisting of irregular particles; TheNi-Co/MD catalyst were Co2NiO4, Co3O4and NiO with a surface of fluffy-balls like particles; The Ni-Cu/MD catalyst were (Cu0.2Ni0.8)O and NiO with a layerstructure; The Ni-Ce/MD catalyst were NiO and CeO2particles with a uniformparticle size; The Ni-La/MD catalyst were NiO and La2O3constructing of uniformspheres.Subsequently, organic municipal solid waste catalytic pyrolysis was carriedout in a self-designed fixed bed reactor. The pyrolysis temperature and particle sizeof the feedstock were investigated, the results showed that both the increase oftemperature and reduce particle size can lead to improve the gas quality. Forincreasing the pyrolysis temperature, higher temperature promote the endothermicreactions and helps tar catalytic cracking to gas. While smaller particle size leads tohigher heating rates with a little difference in temperature, which helps releasevolatile gases. Comparing the difference of the catalysts, the catalytic activit y ofthe catalysts were arranged from high to low as Ni-Fe/MD>Ni-La/MD>Ni-Ce/MD>Ni-Co/MD>Ni-Cu/MD. Higher catalytic activity both helps improvethe quality of the gas and increas the H2and CO content in the gas composition. |
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