高级检索

温度对内旋式移动床热解产物的影响规律研究

Influence law study of temperature on low rank coal pyrolysis products distribution and quality with inner-rotatory moving bed reactor

  • 摘要: 低阶煤热解产物的产率和性质与反应器类型及热解温度等工艺条件密切相关,直接影响下游产业链的开发与延伸,一直是煤热解工艺开发过程中关注的重点。为获得满足产物后续规模化利用要求的最优热解工艺条件,采用1 kg/h内旋式移动床连续热解试验炉,以神木煤为原料,研究热解温度对半焦燃烧性、可磨性、稳定性以及焦油产率和组分分布的影响规律。结果表明:内旋式移动床热解炉控制热解温度500~800 ℃,热解时间150 min时,半焦产率为68.53%~78.62%,焦油产率先升高后降低,在650 ℃时最高,为7.52%;连续试验中半焦挥发分波动在1个百分点以内,气流着火温度为562.1~730.5 ℃,着火性能处于易燃和中等可燃范围,哈氏可磨性指数随着热解温度先升高后降低;热解温度控制为600~700 ℃,获得较高焦油产率的同时,半焦质量可满足电站锅炉和高炉喷吹规模利用的要求;通过反应器温度场控制可以实现焦油组分的调控,反应器底部温度650 ℃,中上部温度450~550 ℃时,焦油中重质组分含量(>360 ℃馏分)最低为25.68%,有利于后续蒸馏、加氢等处理;反应器中上部温度高于550 ℃时,挥发物二次反应加剧,导致轻质组分含量降低。

     

    Abstract: The yield and characteristic of pyrolysis products of low rank coal are closely related to the reactor type and process conditions such as pyrolsis temperature,and further also influence development and extension of downstream processing chain,which attracts more attention during the R&D of new pyrolysis technology.In order to obtain the optimal pyrolysis process conditions to meet the requirements of subsequent large-scale utilization of pyrolysis products,a continuous experimental equipment of an inner-rotatory moving bed reactor with processing capacity of 1 kg/h,was used to research the influence of temperature on the pyrolysis products yield and quality of Shenmu coal,and the characterization of products,including the combustibility,grindability and stability of semicokes,yield and components distribution of coal tar and so on.The results showed that the yields of semicoke were from 68.53% to 78.62% under conditions of pyrolysis temperature at 500~800 ℃ and pyrolysis time 150 min,coal tar yield reached the max value 7.52% at 650 ℃ with increasing pyrolysis temperature.The volatile component of semicokes fluctuated less than 1 percentage point during continuous tests,meanwhile,ignition performance were at the levels of high or medium combustible with the ignition temperature of 562.1~730.5 ℃.Hardgrove grindability index of semicokes increased at first and then decreased with increasing pyrolysis temperature.The pyrolysis temperature of 600~700 ℃ was suitable condition for the new technology to produce semicokes that satisfied the quality requirements of large-scale power plant boiler and blast furnace injection,and obtained a higher tar yield at the same time.Quality of coal tar could be controlled by reducing the temperature rise using the method of stratified temperature distribution.When the bottom temperature of the reactor was 650 ℃ and the temperature of the middle and upper parts is 450~550 ℃, the lowest content of heavy components (>360 ℃ fraction) in tar was 25.68%, which is conducive to further distillation and hydrogenation. When the temperature of middle and upper part was higher than 550 ℃, the secondary reaction of volatiles would be intensified, which led to the decrease of light components.

     

/

返回文章
返回