摘要
采用高温水平管式炉热解制取含有机结合态钠和无机态钠的木质素半焦,利用扫描电镜/能谱分析仪(SEM/EDS)和热重分析仪(TG)对半焦的形貌、元素分布及气化特性进行研究,借助热重红外联用技术(TG-FTIR)考察2种状态钠对木质素半焦气化反应性影响机理。结果表明,随着制焦温度由400℃增加到800℃,结合态钠木质素半焦表面出现大量鼓泡,半焦表面钠元素相对含量由5.36%增加到15.72%,半焦的CO_2和水蒸气气化碳转化率分别增加30%和20%;无机态钠催化木质素实验结果与结合态钠木质素相反。反应温度低于600℃时,结合态钠与木质素半焦反应主要为—CO_2Na与半焦反应;反应温度600~800℃范围内,主要为—CO_2Na和—CONa与半焦反应;当温度高于800℃时,主要为—CONa与半焦反应。
The sodium sahs in black liquor exists in two main forms： as phenolic sodium （--CONa） and carboxylate sodium （--COONa） groups （PCSG） forming a part of alkali lignin or as dissolved salt （NaOH and Na2CO3 ）. The purpose of this study is to investigate the effect of inorganic and organic bound sodium on the char characteristics of alkali lignin, char samples were prepared by a high- temperature furnace as pyrolysis temperature at 400℃, 600℃ and 800℃, respectively. The char morphology, elemental distribution, gasification reactivity and catalytic mechanism were studied by scanning electron microscopy/energy spectrum analyzer （SEM/EDS） , thermal gravimetric analysis （TG） and thermogravimetric analyzer coupled with Fourier transform infrared spectrometry （TGA - FTIR）. The results suggested that for organic bound sodium lignin, a large number of bubbling occurred at the char surface and the sodium content of char surface was increased from 5.36% to 15.72% as the pyrolysis temperature was increased from 400℃ to 800℃. Meanwhile, the carbon conversions of CO2 and steam gasification were increased by 30% and 20% , respectively. The effect of organic bound sodium on the reaction characteristic was varied with temperature. When the reaction temperature was lower than 600℃ , the reaction mainly occurred between --CO2Na and char. As the temperature was in the range of 600- 800℃, both --CO2Na and --CONa can react with char. As the temperature was higher than 800℃, the reaction mainly occurred between --CONa and char.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2017年第3期332-337,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(31500492)
浙江省自然科学基金项目(LY16C160005)
浙江理工大学科研启动基金项目(14012079-Y)
化学工程与技术浙江省高校重中之重学科优秀青年人才培养基金项目(ZYG2015012)
纺织科学与工程浙江省高校重中之重学科优秀青年人才培养基金项目(2013YBZX06
ZYG2015012)
关键词
碱木质素
半焦
气化
结合态钠
无机态钠
alkali lignin
char
gasification
organic bound Na
inorganic Na
