Co-combustion Of Energy Plants And Lignite

Arundo donax and Spartina alterniflora are energy plants with high calorific value,high production,low land requirement and low sulfur dioxide emission,which have great potential.At the same time,China has abundant lignite resource without thoroughgoing utilization.Therefore,co-firing of energy plants and lignite can effectively alleviate the fossil energy shortage and environmental pollution.Arundo donax,Spartina alterniflora and Yunnan lignite,Mengxi lignite were selected to investigate thermo-chemical characteristics of energy plants and lignite by using thermogravimetric analysis(TGA)method in this study.Individual thermal behavior of energy plants and lignite were investigated in this thesis.Effect of heating rate on the pyrolysis process was evaluated at different heating rates of 10,20 and 30 °C/min,respectively.Also,major degradation products of energy grass and lignite were detected by mass spectrometry(MS)analyses,the components of the gas and product distribution of samples were discussed in this research.The integrated area of each MS curve was also calculated to evaluate releasing strength.Individual combustion and co-combustion characteristics of energy plants and lignite were investigated in the thermogravimetric analyzer.The ignition temperature and burnout temperature were defined by tangent of TG curves.The ignition index and comprehensive combustion index were calculated to evaluate the combustion performance.Besides,energy plants and lignite were mixed at different radios to study the effect of blending.It was found that 30% for Arundo donax in Yunnan lignite and 10% for Spartina alterniflora in Mengxi lignite were the perfect ratios according to the combustion characteristic parameters.To figure out the synergistic effect,the theoretical weight loss of a blend which was obtained from the weighted sum of reference materials was compared with the practical loss.The results showed calculated and experimental weight loss matched each other very well,which presented there was no synergistic effect between ene rgy plants and lignite.The combustion process was mainly characterized by devolatilization stage and char oxidation stage.Based on above research,the Coats-Redfern model was employed to analyze the two combustion stages of energy plants and lignite,respectively.The combustion kinetic parameters of each sample were determined out and linearly dependent coefficients were over 0.98.