In-situ study of Ningdong char particles gasification characteristics on the interface of ash layer and slag
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摘要: 以典型宁东煤-羊场湾煤为气化原料, 采用热重分析仪和高温热台显微镜原位研究了1100、1200、1300 ℃下煤焦颗粒及其在灰层界面和熔渣界面的气化反应。结果表明, 不同气化温度下灰层界面和熔渣界面的形态变化是影响煤焦颗粒气化反应性的主要因素。气化温度为1100 ℃, 灰层在高温下收缩并包裹在煤焦颗粒表面, 阻碍气化剂与煤焦颗粒的接触, 使煤焦颗粒气化反应速率降低, 而熔渣界面未发生明显变化, 其界面处煤焦气化反应速率不变。气化温度为1300 ℃, 灰层界面与熔渣界面均转变为液态, 在表面张力作用下煤焦颗粒破碎, 有效反应面积变大, 传热速率增大, 进而提高了煤焦的气化反应速率。Abstract: A thermogravimetric analyzer and in-situ heating microscope were used to study gasification reaction of coal char particles on the interface of ash layer and slag at 1100, 1200 and 1300 ℃, using typical Ningdong coal-Yangchangwan coal as gasification raw material. The results show that the shape change of ash layer interface and slag interface under different gasification temperature is the main factor that affects the gasification reactivity of coal char particles. When the gasification temperature is 1100 ℃, the ash layer shrinks and wraps on the surface of coal char particles at high temperature, preventing the contact between gasifying agent and coal char particles and reducing the gasification reaction of char particle. However, the interface of slag does not change significantly, and the gasification reaction rate of coal char on the slag interface remains unchanged. When the gasification temperature is 1300 ℃, the interface of both ash layer and slag turns into a liquid phase. Under the surface tension, the char particles are broken, the effective reaction area became larger, and the heat transfer rate increases, thereby increasing gasification reaction rate of the coal char.
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图 2 1100、1200和1300 ℃煤焦颗粒、灰层/熔渣层界面煤焦颗粒气化反应活性
Figure 2 Gasification reaction activity of char particles, char particles at the interface of ash layer and slag at 1100, 1200 and 1300 ℃
(a): gasification temperature at 1100 ℃; (b): gasification temperature at 1200 ℃; (c): gasification temperature at 1300 ℃
图 3 1100、1200和1300 ℃煤焦颗粒气化反应
Figure 3 Gasification reactions of char particles at 1100, 1200 and 1300 ℃
图 4 41100 ℃灰层界面煤焦颗粒的气化反应
Figure 4 Gasification reactions of char particles at the interface of ash layer at 1100 ℃
图 5 1200和1300 ℃灰层界面煤焦颗粒的气化反应
Figure 5 Gasification reactions of char particles at the interface of ash layer at 1200 and 1300 ℃
图 6 1100和1200 ℃渣层界面煤焦颗粒的气化反应
Figure 6 Gasification reactions of char particles at the interface of slag layer at 1100 and 1200 ℃
图 7 1300 ℃熔渣界面煤焦颗粒的气化反应
Figure 7 Gasification reactions of char particles at the interface of slag layer at 1300 ℃
表 1 样品的煤质分析
Table 1 Characteristic data of tested coal sample
Proximate analysis wd/% Ultimate analysis wd/% Ash fusion temperature t/℃ V FC A C H N S O* DT ST HT FT 26.64 56.81 16.55 64.42 3.63 0.67 1.14 13.59 1183 1201 1207 1.14 note:V: volatile matter; FC: fixed carbon; d: dry basis; *: calculated by difference; DT: deformation temperature; ST: softening temperature; HT: hemispherical temperature; FT: flow temperature 
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表 2 样品的灰化学组成
Table 2 Ash chemical compositions of raw sample
Sample Composition w/% SiO2 Al2O3 Fe2O3 CaO Na2O K2O MgO YCW 41.59 18.28 9.27 12.25 2.19 1.51 4.77
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