硝酸铁催化热解桉木制备半焦及其反应性研究
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摘要
【目的】生物质热解可生成生物半焦及生物油,生物半焦可进一步气化生成高附加值的含氢的合成气,但生物半焦的反应性对气化反应有着重要的影响,研究Fe(NO_3)_3在热解过程中对桉木半焦反应性的影响对制备高反应性生物半焦有重要意义。【方法】通过浸渍法将桉木负载不同浓度的Fe(NO_3)_3溶液中,考察Fe~(3+)催化对热解半焦燃烧反应性的影响。【结果】Fe(NO_3)_3催化可明显提高桉木热解半焦的反应性,随着Fe(NO_3)_3浓度由0.17 mol·L~(-1)增加到0.35 mol·L~(-1),半焦的反应性由0.03 min~(-1)增加到0.06 min~(-1),其Laman散射峰强度增大,半焦结构的d_(002)间距由催化前的0.341 nm增至0.382 nm。热解温度由600℃升到800℃时,半焦的反应性下降。【结论】采用硝酸铁催化热解桉木粉可制备出高反应性桉木半焦,450℃下测定的半焦与O_2的燃烧反应活性增大,随着热解温度升高,桉木半焦的反应性下降。
【Objective】Biomass pyrolysis can produce biochar and bio-oil,and biochar can be further gasified to produce high valued syngas with hydrogen,but the reactivity of the biochar has an important influence on the gasification reaction. The effect of Fe(NO_3)_3 on the reactivity of eucalyptus char during pyrolysis is important for the preparation of highly reactive biochar.【Methods】In this research,the effect of Fe~(3+)catalysis on the combustion reactivity of pyrolysis biochar was investigated by impregnation that eucalyptus were immersed in different concentration of Fe(NO_3)_3 solution.【Results】The results showed that Fe(NO_3)_3 catalysis could significantly improve the reactivity of eucalyptus pyrolysis biochar.As the concentration of Fe(NO_3)_3 increased from 0.17 mol·L~(-1) to 0.35 mol·L~(-1),the reactivity increased from 0. 03 min~(-1) to 0. 06 min~(-1). The intensity of Laman scattering peak also increased and the d_(002) spacing of the biochar structure increased from 0. 341 nm to 0. 382 nm before the catalysis.While the pyrolysis temperature increased from600℃ to 800℃,the reactivity of biochar decreased.【Conclusion】Eucalyptus biochar with high reactivity can be prepared by catalytic pyrolysis of eucalyptus powder with Fe(NO_3)_3,the combustion reactivity between biochar and O_2 has greatly enhanced under 450℃. As the pyrolysis temperature increases,the reactivity of the eucalyptus biochar decreases.
【Objective】Biomass pyrolysis can produce biochar and bio-oil,and biochar can be further gasified to produce high valued syngas with hydrogen,but the reactivity of the biochar has an important influence on the gasification reaction. The effect of Fe(NO_3)_3 on the reactivity of eucalyptus char during pyrolysis is important for the preparation of highly reactive biochar.【Methods】In this research,the effect of Fe~(3+)catalysis on the combustion reactivity of pyrolysis biochar was investigated by impregnation that eucalyptus were immersed in different concentration of Fe(NO_3)_3 solution.【Results】The results showed that Fe(NO_3)_3 catalysis could significantly improve the reactivity of eucalyptus pyrolysis biochar.As the concentration of Fe(NO_3)_3 increased from 0.17 mol·L~(-1) to 0.35 mol·L~(-1),the reactivity increased from 0. 03 min~(-1) to 0. 06 min~(-1). The intensity of Laman scattering peak also increased and the d_(002) spacing of the biochar structure increased from 0. 341 nm to 0. 382 nm before the catalysis.While the pyrolysis temperature increased from600℃ to 800℃,the reactivity of biochar decreased.【Conclusion】Eucalyptus biochar with high reactivity can be prepared by catalytic pyrolysis of eucalyptus powder with Fe(NO_3)_3,the combustion reactivity between biochar and O_2 has greatly enhanced under 450℃. As the pyrolysis temperature increases,the reactivity of the eucalyptus biochar decreases.
引文
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[9]YANG J P,MA S,ZHANG J Y,et al.Mercury removal by magnetic biochar derived from simultaneous activation and magnetization of sawdust[J].Environment Science&Technology,2016,50(21):12040-12047.
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[13]ZOU J,YANG H P,ZENG Z W,et al.Hydrogen production from pyrolysis catalytic reforming of cellulose in the presence of K alkali metal[J].International Journal of Hydrogen Energy,2016,41(25):10598-10607.
[14]LI T T,ZHANG L,DONG L,et al.Effects of gasification atmosphere and temperature on char structural evolution during the gasification of collie sub-bituminous coal[J].Fuel,2014,117(Part B):1190-1195.
[2]欧阳平凯,陈可泉,贾红华,等.低劣生物质制备生物甲烷的研究进展与展望[J].广西科学,2014,21(1):1-5.OUYANG P K,CHEN K Q,JIA H H,et al.Progress and prospect of biomethane production with low-valued biomass as material[J].Guangxi Sciences,2014,21(1):1-5.
[3]胡东南.农林废弃物生物质压块燃料[J].广西科学院学报,1994,10(2):68-69.HU D N.An organism pressing fuel derived from the trash of farming and forestry[J].Journal of Guangxi Academy of Sciences,1994,10(2):68-69.
[4]TAY H L,LI C Z.Changes in char reactivity and structure during the gasification of a victorian brown coal:Comparison between gasification in O2and CO2[J].Fuel Processing Technology,2010,91(8):800-804.
[5]廖艳芬,王树荣,骆仲泱,等.钙盐催化纤维素快速热裂解机理试验研究[J].太阳能学报,2005,26(5):654-659.LIAO Y F,WANG S R,LUO Z Y,et al.Catalysis mechanism of calcium salt in cellulose rapid pyrolysis[J].Acta Energiae Solaris Sinica,2005,26(5):654-659.
[6]王树荣,廖艳芬,文丽华,等.钾盐催化纤维素快速热裂解机理研究[J].燃料化学学报,2004,32(6):693-698.WANG S R,LIAO Y F,WEN L H,et al.Catalysis mechanism of potassium salt during rapid pyrolysis of cellulose[J].Journal of Fuel Chemistry and Technology,2004,32(6):693-698.
[7]QUYN D M,WU H W,LI C Z.Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal.Part1.Volatilisation of Na and Cl from a set of Na Cl-loaded samples[J].Fuel,2002,81(2):143-149.
[8]KEOWN D M,LI X J,HAYASHI J I,et al.Evolution of biomass char structure during oxidation in O2as revealed with FT-Raman spectroscopy[J].Fuel Processing Technology,2008,89(2):1429-1435.
[9]YANG J P,MA S,ZHANG J Y,et al.Mercury removal by magnetic biochar derived from simultaneous activation and magnetization of sawdust[J].Environment Science&Technology,2016,50(21):12040-12047.
[10]RAWAL A,JOSEPH S D,HOOK J M,et al.Mineral-biochar composites:Molecular structure and porosity[J].Environ Sci Technol,2016,50(14):7706-7714.
[11]ZHANG M,GAO B,VARNOOSFADERANI S,et al.Preparation and characterization of a novel magnetic biochar for arsenic removal[J].Bioresource Technology,2013,130:457-462.
[12]SHIM H S,HURT R H.Thermal annealing of chars from diverse organic precursors under combustion-like conditions[J].Energy&Fuels,2000,14(2):340-348.
[13]ZOU J,YANG H P,ZENG Z W,et al.Hydrogen production from pyrolysis catalytic reforming of cellulose in the presence of K alkali metal[J].International Journal of Hydrogen Energy,2016,41(25):10598-10607.
[14]LI T T,ZHANG L,DONG L,et al.Effects of gasification atmosphere and temperature on char structural evolution during the gasification of collie sub-bituminous coal[J].Fuel,2014,117(Part B):1190-1195.