化工学报 ›› 2020, Vol. 71 ›› Issue (12): 5735-5744.DOI: 10.11949/0438-1157.20200530

• 能源和环境工程 • 上一篇    下一篇

菱镁矿输送床轻烧过程反应与产物微观结构特性

孙聪1(),闫博威1,蔡长庸1,韩振南1(),许光文1,2()   

  1. 1.沈阳化工大学能源与化工产业技术研究院,资源化工与材料教育部重点实验室,辽宁 沈阳 110142
    2.中国科学院过程工程研究所多项复杂系统国家重点实验室,北京 100190
  • 收稿日期:2020-05-08 修回日期:2020-06-30 出版日期:2020-12-05 发布日期:2020-12-05
  • 通讯作者: 韩振南,许光文
  • 作者简介:孙聪(1994—),男,硕士研究生,1187875448@qq.com
  • 基金资助:
    辽宁省教育厅重点项目(LZ2017001);国家自然科学基金项目(U1903130)

Characteristics of reaction and product microstructure during light calcination of magnesite in transport bed

SUN Cong1(),YAN Bowei1,CAI Changyong1,HAN Zhennan1(),XU Guangwen1,2()   

  1. 1.Institute of Industrial Chemistry and Energy Technology, Laboratory on Resources Chemicals and Materials of Ministry of Education, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning, China
    2.State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2020-05-08 Revised:2020-06-30 Online:2020-12-05 Published:2020-12-05
  • Contact: HAN Zhennan,XU Guangwen

摘要:

利用高温烟气加热实验室规模输送床模拟菱镁矿闪速轻烧工业输送床反应器,建立基于热重分析计算菱镁矿中MgCO3分解率方法,研究了煅烧条件和原料粒径对菱镁矿细粉输送床分解的转化率和产品活性的影响,揭示了煅烧过程中产物微观结构变化特性。菱镁矿粉(<150 μm)轻烧为秒级快速反应,仅需1~2 s菱镁矿中MgCO3分解率即可达98%以上,验证了输送床闪速轻烧技术的可行性。输送床煅烧产物的柠檬酸显色时间17~55 s,活性显著高于固定床煅烧产物(显色时间294 s),且产物活性由菱镁矿分解率和微观结构共同决定;煅烧过程中产物MgO晶粒尺寸逐渐增大,表面结构由疏松多孔变为致密光滑,该结构变化可在数秒内完成。

关键词: 菱镁矿, 轻烧, 流态化, 活性, 微观结构

Abstract:

A gas-heating laboratory transport bed was adopted to simulate the industrial transportbed reactor for flash calcination of magnesite, and a method based on TG analysis of a reacted sample was further developed to calculate the decomposition rate or conversion of its containing MgCO3. The study investigated how the conversion and product reactivity as well as microstructure vary with reaction conditions including temperature, particle size and times of re-calcination for powder magnesite. Magnesite powder (<150 μm) calcination is a quick reaction that reaches 98% decomposition of its containing MgCO3 in 1—2 s,corroborating the feasibility of magnesite flash-calcination in transport bed reactors. The coloration time given by the citric acid chromogenic method was 17—55 s and 294 s for the obtained products from transport and fixed beds, respectively. This proves the obviously higher activity and thus improved microstructure of the product from transport bed. During the calcination process, the MgO grain size of the product gradually increases, and the surface structure changes from loose and porous to dense and smooth. This structural change can be completed within a few seconds.

Key words: magnesite, light calcination, fluidization, reactivity, microstructure

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