Study On Pyrolysis Characteristics Of Straw In Central China And Southwest

Biomass is one of the world’s fourth largest energy, straw is a kind of important biomass resources. Many countries attach importance to the use of biomass pyrolysis technology,getting Biomass energy is one of the most promising way by Using pyrolysis technology in the future. In the study,rape, rice, maize, wheat and cotton stalks as the research object. The straw pyrolysis experiment was carried out by using SDT- Q600 synchronous thermal analyzer. combined with wood fiber content and thermo-chemical engineering properties of Biomass pyrolysis characteristics. Pyrolysis kinetics model was established,obtaining pyrolysis kinetics parameters. the main conclusions are as follows:(1)Straw pyrolysis TG curve shows a substantially similar shape,curve rendered as "S" shape. But in terms of starting and ending temperature,rate of weight loss and weight loss rate peak point,the residue content of the pyrolysis reaction is characterized there are some differences. The pyrolysis process is divided into the pre-heating and drying phase,preheated solution phase,solid phase decomposition and carbon residue decomposition stage in four phases.(2)The TG curves of rape,rice,wheat and cotton samples substantially coincide,TG curves significantly different from other samples of corn sample. Five kinds of straw sample of DSC curves in similar, But each sample DSC curve between heat flow values are not equal;the DTG curves of wheat straw samples are not the same between three areas,the maximum pyrolysis rate is also not equal each,there is a clear peak in the lower temperature side of wheat straw samples from Yunnan and Hubei;the DSC curve difference is significant between wheat straw samples from three distinct areas,DSC heat flow curve of each sample are not equal,wheat straw samples apparent peak in Sichuan,the other two areas the straw sample was not obvious. The species and origin are a greater influence on the pyrolysis characteristics of biomass straw.(3)The first phase of major weight loss rape straw pyrolysis activation energy distribution in the range of 35.10 ~ 37.30 k J / mol,The first phase of the frequency factor distribution in the range of 0.12 ~ 0.39 S-1; the second phase of the activation energy distribution in the range of 112.77 ~ 124.99 k J / mol,The second phase of the frequency factor distribution in the range of 7.07E+06~8.73E+07 S-1, the linear correlation coefficient is 0.99. The first phase of major weight loss wheat straw pyrolysis activation energy distribution in the range of 48.51~132.37 k J/mol,The first phase of the frequency factor distribution in the range of 5.64~8.85E+07 S-1;the second phase of the activation energy distribution in the range of 75.07~144.38 k J/mol,The second phase of the frequency factor distribution in the range of 2.27E+03~3.4E+09 S-1,the linear correlation coefficient is 0.99. The first phase of major weight loss corn straw pyrolysis activation energy distribution in the range of 59.79~89.86 k J/mol,The first phase of the frequency factor distribution in the range of 59.79~89.86 k J/mol;the second phase of the activation energy distribution in the range of 96.35~121.98 k J/mol,The second phase of the frequency factor distribution in the range of 1.09E+05~3.89E+07 S-1, the linear correlation coefficient is 0.99. The rice straw sample weight loss phase of activation energy solutions ranged from 89.21 to101.08 k J/mol,the frequency factor distribution in the range of 4.97 E + 04 ~ 3.53 E + 05 S-1,the linear correlation coefficient is 0.99. Rape straw heat required in the range of 414.41~1182 J/g,wheat straw heat required in the range of-187.84~2525.37 J/g, corn straw heat required in the range of 2486.88~2873.92J/g,rice straw heat required in the range of 1680.75~2374.5J/g. Wheat straw wide range of heat,heat concentrated corn straw. Pyrolysis heat canola, wheat,maize and rice straw are very different. Heat corn straw sample average of the maximum,wheat straw pyrolysis heat the sample mean minimum. Description Biomass category affects a lot of heat for pyrolysis.(4)Compare the heat absorption between wheat and corn straw,the heat absorption of Hubei region is higher than other two region of straw sample size;both straw of Hubei also has a higher LHV,it shows regional influential straw thermal desorption heat,straw pyrolysis species also has a high heat required LHV generally more.