| The utilization and development of bioenergy plays an important role to alleviate the energy crisis and environmental pollution.Bamboo is one of potential resources as bioenergy products in China.Bamboo molding charcoal is the most efficient way to use its residues as commercialized utilization.In this study,X-Ray Diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),Thermogravimetry(TGA),Thermogravimetry-Fourier Transform Infrared Spectroscopy(TG-FTIR),pyrolysis gas chromatography mass spectrometry(Py-GC-MS)was used to investigate the pyrolysis characteristics and prouducts to investigate its pyrolysis mechanism.Optimum process of manufacturing bamboo charcoal was gotten including carbonization temperature,dwelling time and heating rate.The main results of research are as follows:(1)The main pyrolysis stage of bamboo was 250~450? of temperature and mass loss was 55.67%.The crystalline region of cellulose was pyrolyzed when temperature was us to 350?.Proximate analysis showed the content of fixed carbon and ash increased with increase in temperature,whose maximum value were 87.42% and 5.88%,respectively.The content of volatiles decreased to 28.47% within 300~350? of temperature.The heating value gradually increased and then decreased and the maximum value of 32442J/Kg was found at 650? of temperature.FTIR showed that functional groups of the principal component peak gradually reduced or disappeared,especially for the absorbance of cellulose or hemicellulose in 1090cm-1 and lignin in 1510cm-1;TG-FTIR curves showed that carbon dioxide(CO2),carbon monoxide(CO),and methane(CH4)were main pyrolysis products of bamboo which main released at 250~450? of temperature.Py-GC-MS results indicated the liquid products of pyrolysis process contained more than ninety kinds of organics,which included Benzofuran,2,3-dihydro-,3-Hydroxy-4-methoxycinnamic acid,4-Hydroxy-3-methylacetophenone,which were the important chemical processing intermediates.(2)The TG curves showed the combustion process of charcoal changed two steps into one step,and activation energy gradually increased and then decreased.The maximum activation energy was 153KJ/mol at 550? of temperature and the minimum value was 38.1KJ/mol at 750? of temperature.Cone results showed that the stage of flame combustion of carbonized bamboo disappeared when it was pyrolyzed,the total smoke product was decreased,combustion characteristics of charcoal showed more stabilization and the time of combustion prolonged respectively.(3)Compared with different heating model,uniform-heat craft was not only helpful to short the dwelling time and increase the yield of charcoal,but also keep the quality.The optimum process was that gradually increasing temperature to 200?from room temperature with 20?/min of heating rate and dwelling time was 60 min.Then carbonization temperature was gradually increased to 500? of temperature with 1?/min of heat rate.Finally,carbonization temperature was increased to 650? of temperature with 20?/min of heating rate and dwelling time was 180 min.In the optimum process,product yield was 27.25%,moisture content was 1.07%,heating value was 32935J/Kg,fixed carbon was 89.51%,volatiles content was 4.15% and ash content was 5.72%,respectively.TG curves showed the combustion region of charcoal was 266~526? of temperature,and inignation temperature was 431?,which was lower than 64?of temperatue compared with the charcoals in the markets. |
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