Pyrolysis Properties Of Municipal Organic Wastes And Study On The Improvement Effects Of Biochar On Soil

Biochar technology can not only reduce municipal organic waste, it also canincrease carbon storage、serve as soil active conditioners and improve soil fertility whenstored in soil, it has significant effect to maintain soil ecosystem balance and mitigateglobal warming, so biochar technology is getting more and more attention. However, inthe study of biological carbon, the raw material is limited to biomass of vegetation、straw、peanut shells、palm shell、sludge and so on, there are very few people to carry outbiochar techlonogy municipal organic waste pyrolysis, there are also few people studythe formation mechanism of biochar structural characteristics、carbon sequestration andimproving soil performance. The paper carried out the pyrolysis characteristics ofmunicipal organic waste and the effect of biochar on soil properties、study theweightloss properties of each single component and mixed wastes pyrolysis and theeffect of pyrolysis temperature and heating rate on the biochar yield and surfacestructure of biochar on soil pH and CEC。The purpose is to explore the technologicalparameter of biochar pyrolysis from municipal organic waste and provide theoreticalbasis for application of municipal organic waste pyrolysis technology and biocharsequestration technology. Through the experimental study, conclusions were drawn asfollows:1）when the final temperature is500°C, the carbon yield of single componentsamples is respectively: kitchen：30%、plastic：52%、cloth：20%、leaves and pericarp：35%、paper:32%and wood:26%; and the rapid weightlessness interval is: kitchen:270~350°C、plastic:260~310°C and400~500°C、cloth:300~390°C、paper:250~390°C、leaves and pericarp:150~400°C、wood:350~400°C. The TG curve of plastic is slowbecause of the large content of polymer which is difficult to decompose, so theweightlessness rate is the lowest. The weight loss interval of mixed wastes is260~720°C, the organic matter has basicly decomposed after720°C and the carbonyield is24%.2）The TG curves of different heating rate （10、30、50°C/min） indicating that，the faster the heating rate is, the higher the start-stop temperature is, the faster theweight loss is, the more narrow of rapid weightloss temperature interval is, and thegreater fluctuation of heat curve; the carbon yield is highest when the heating rate is30°C/min for municipal organic waste. 3）As the final pyrolysis temperature increased gradually,the C content of biocharincreased, and H and O content decreased, so H/C ratio gradually decreased, whichindicating that aromatic degree of biochar gradually increased with increasingtemperature; O/C reduced gradually as the final pyrolysis temperature increased,indicating that the oxygen-functional groups was gradually reducted on the biocharsurface, and the hydrophilism was gradually weakened; the BET-surface area andporosity increased as the final pyrolysis temperature increased gradually to700°C; therewere hydroxy-OH、fatty C-H、carboxyl group-COOH、aromatic rings C-H、C=C onthe surface of biochar.4）Adding biochar to soil can increase the CEC and pH significantly aftercultivating20days, and remained stable in the next60days. So,biochar could improvethe physical and chemical properties of the soil, and improve soil fertility.5）The experiment indicating that，the optimum conditions for minicipal organicwaste pyrolysis to produce biochar were: heating rate:30°C/min、final temperature:700°C.