稻秆与煤混燃过程中碱金属迁移转化规律研究  

Study on Migration Mechanism of Alkali Metals During Co-firing of Rice Straw and Coal

作　　者：开兴平[1] 杨天华[1] 孙洋[1] 贺业光[1] 李润东[1] 魏砾宏[1] 

机构地区：[1]沈阳航空航天大学清洁能源与环境工程研究所,辽宁省沈阳市110136

出　　处：《中国电机工程学报》2012年第8期133-138,160,共6页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973计划)(2011CB201500);国家自然科学基金项目(50706030);辽宁省高校创新团队项目(2007T141)~~

摘　　要：以化学热力学平衡计算为基础,利用自行设计的立式管式炉结合X射线衍射(X-ray power diffraction,XRD)、扫描电子显微镜(scanning election microscope,SEM)等分析测试手段探讨稻秆与煤在850℃的条件下混合燃烧碱金属K、Na的迁移转化规律。结果表明,碱金属的主要气态组元KCl、KOH、NaCl、NaOH随稻秆含量的增多而增加,且氯化物的析出量大于氢氧化物的析出量;煤中某些矿物组分或元素对K的气相析出有抑制作用,但对Na的抑制作用不明显;灰中K、Na的存在形式直接受原料秸秆含量的影响,稻秆含量为0%和20%时,灰中K以K2O Fe2O3为主,Na则以Na2SO4为主,稻秆含量大于50%时,K2O 2SiO2、Na2SiO3随稻秆含量的增多表现出上升趋势,K2SO4、Na2SO4趋势则相反,原料K还会以KAlSiO4、KAlSi3O8的形式滞留在灰中。The migration mechanism of alkali metals during co-firing of rice straw and coal in a self-made vertical tube furnace at 850 ℃ was studied on the basis of thermodynamic equilibrium calculations.The X-ray powder diffraction（XRD） and scanning electron microscope（SEM） were performed on the selected bottom ashes.The results indicate that the amount of gaseous KCl,KOH,NaCl and NaOH increase with rice straw content increasing and the concentrations of gaseous alkali chlorides are more than gaseous alkali hydroxides.The volatile potassium from rice straw is reduced after co-firing rice straw with coal due to the capture by reactions with mineral compositions or elements in coal.While the release of sodium is independent on the proportion of rice straw and coal in the fuels.The formation of alkali metals in ashes is related to the composition of fuel.When the proportion of rice straw is 0% and 20%,potassium and sodium in ashes are in the form of K2O·Fe2O3 and Na2SO4 respectively.When the mixing ratio of rice straw is more than 50%,K2O·2SiO2 and Na2SiO3 increase with rice straw content increasing,which is in contrast to K2SO4 and Na2SO4.Meanwhile,some potassium in fuel can be captured in the form of KAlSiO4 and KAlSi3O8.

关 键 词：碱金属 热力学平衡计算 混燃 稻秆 煤 

分 类 号：TK6[动力工程及工程热物理—生物能]