240t/d固体热载体粉煤热解工艺及中试研究

Pilot plant study on 240 t/d pulverized coal pyrolysis technology with solid heat carrier

以粉煤分质梯级利用为背景,提出了一种固体热载体粉煤热解工艺,该工艺主要包含基于循环流化床技术的热解-缺氧燃烧耦合系统、缺氧燃烧煤气的脱灰及余热回收系统和热解煤气的脱灰及油气净化分离系统,并于2016年底完成了该工艺中试装置72 h满负荷连续稳定运行。中试试验以0~10 mm的神木煤为原料,原料煤满负荷输入量为240 t/d,试验结果表明:热解煤气中CH_4和H_2的体积分数分别为35.3%和12.5%,热解煤气热值达到20 920 kJ/Nm^3以上;热解焦油产率为9.24%,为原料煤格金焦油产率的81.8%;产品焦油的含尘率为0.47%,焦油中的正庚烷可溶物质量分数为84.3%;热解半焦的固定碳含量为86.3%,热值为29 985.5 kJ/kg。计算表明,该中试装置72 h连续稳定运行期间的物料平衡偏差为1.93%,能量利用效率为87.95%。

Taking the cascade utilization of pulverized coal as the background,a pulverized coal pyrolysis technology with solid heat carrier was proposed in this study.The proposed technology mainly includes the pyrolysis-gasification coupled system based on circulating fluidized bed,the system for removing coal ash and waste heat recovery from gasification gas and the system of deashing,purification and separation for pyrolysis oil-gas. The pilot plant of this technology has achieved a continuous and stable operation for 72 hours at the end of 2016.In the pilot experiment,the coal of 0-10 mm was used as the raw material and the feed amount of raw coal was a full load of 240 t/d.The experimental results show that the volume content of CH_4 and H_2 in the pyrolysis gas are 35. 3% and 12. 5%,and the calorific value of the pyrolysis gas is over 20 920 kJ/Nm^3; the yield of pyrolysis tar is 9. 24%,which is 81. 8% of the Gray-King tar yield of raw coal; the dust content of the product tar is 0. 47%,and the mass fraction of N-heptane soluble in tar is 84. 3%; the fixed carbon content in the pyrolysis semicoke is 86. 3% and the calorific value of the semicoke is 29 985 kJ/kg.For the pilot plant that operated continuously and steadily for 72 hours,the calculated mass balance deviation and energy efficiency are 1. 93% and 87. 95%,respectively.