The research on viscosity-temperature characteristics of the mixed slag of biomass and bituminous coal
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摘要: 以神华烟煤和玉米秸秆为实验原料,研究弱还原性气氛下生物质掺混量对神华烟煤的灰熔融特性和黏温特性的影响。利用XRD和SEM对灰渣的矿物质组成和微观形貌进行检测和表征。并利用热力学软件FactSage对不同温度下灰渣的物相及矿物质转化过程进行模拟计算。结果表明,随着玉米秸秆掺混量的增加,灰渣中高熔点的石英、钙长石和堇青石的含量降低,低熔点的钾长石含量增加,在玉米秸秆掺混量为20%(质量分数)时,灰渣的临界黏度温度(tcv)和最低操作温度(tlp)降到最低,此时灰渣的黏度最低,温度升高至1255 ℃时黏度值小于25 Pa·s,满足气化炉的液态排渣要求。结合Urbain均相模型和Einstein-Roscoe非均相模型,以及FactSage软件计算的不同温度下的液相含量得出适合玉米秸秆和神华烟煤混合灰渣的黏度预测经验公式。
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关键词:
- 烟煤与生物质混合燃料 /
- 气化 /
- 灰渣 /
- 熔融特性 /
- 黏温特性
Abstract: Shenhua bituminous coal and corn stalks were selected as experimental materials, and the effects of biomass blending ratio on the ash melting characteristics and viscosity-temperature characteristics of Shenhua bituminous ash in a weakly reducing atmosphere were studied. The mineral composition and micro-morphology of ash were detectd by XRD and SEM, and the phase and mineral transformation of ash at different temperatures were simulated by thermodynamic software FactSage. The results indicate that with the increase in corn stalks addition, the contents of high melting point quartz, anorthite and cordierite in ash decrease, and the content of low melting point potassium feldspar increases. Besides, the critical viscosity temperature (tcv), the lowest operation temperature (tlp) of ash and the viscosity of slag reach to the minimum values as the blending ratio of corn stalk to Shenhua coal is 20%. When the temperature arrives at 1255 ℃, the value of viscosity is less than 25 Pa·s, which can meet the liquid slag discharging requirements of the gasifier. Combining the Urbain homogeneous model with the Einstein-Roscoe heterogeneous model and using the FactSage software to calculate the liquid phase content at different temperatures, an empirical formula for the viscosity prediction of the corn stalks and Shenhua bituminous coal mixed gasification slag has been obtained. -
表 1 神华烟煤和玉米秸秆的工业分析
Table 1 Proximate analysis of Shenhua bituminous coal and corn stalk
Sample Proximate analysis wad/% M A V FC SH 10.21 11.83 31.91 46.05 CS 9.21 5.08 66.42 19.29 表 2 烟煤、玉米秸秆及其混合灰的成分分析
Table 2 Chemical compositions of Shenhua bituminous coal ash, corn stalk ash and blending ashes
Sample Content w/% Na2O MgO Al2O3 SiO2 P2O5 SO3 K2O CaO Fe2O3 SH 1.86 2.34 19.12 58.03 0.50 5.66 1.09 8.29 3.11 CS10 1.69 3.02 17.37 54.72 1.11 5.47 5.40 8.38 2.84 CS20 1.51 3.71 15.59 51.35 1.74 5.27 9.78 8.47 2.57 CS30 1.33 4.41 13.79 47.95 2.37 5.08 14.20 8.57 2.29 CS40 1.15 5.13 11.95 44.46 3.02 4.88 18.75 8.66 2.01 CS50 0.97 5.85 10.09 40.94 3.67 4.67 23.33 8.76 1.72 CS60 0.78 6.59 8.19 37.35 4.34 4.46 28.00 8.86 1.43 CS70 0.59 7.34 6.27 33.71 5.01 4.25 32.74 8.96 1.13 CS80 0.40 8.10 4.31 30.01 5.70 4.04 37.55 9.06 0.83 CS90 0.20 8.87 2.32 26.24 6.40 3.82 42.45 9.16 0.52 CS 0 9.66 0.30 22.42 7.11 3.60 47.43 9.27 0.21 表 3 牛顿型流体模型类型和适用范围
Table 3 Newtonian fluid model types and applications
Model type Applicable conditions Reid Slags containing more than 3% MgO and less than 5% CaO, or where the alkalies exceed 2.5% S2 SiO2: 31%−59%; Al2O3: 19%−37%; Fe2O3: 0−38%; CaO: 1%−37%; MgO: 1%−12%; Na2O+K2O: 1%−6%; silica ratio: 45−75; SiO2/Al2O3: 1.2−2.3 Watt SiO2: 30%−60%; Al2O3: 15%−35%; Fe2O3: 3%−30%; CaO: 2%−30%; MgO: 1%−10%; silica ratio: 40−80; SiO2/Al2O3: 1.4−2.4 Shaw any system Lakatos SiO2: 0.61−0.77; Al2O3: 0−0.05; CaO: 0.09−0.14; MgO: 0−0.10; Na2O: 0.10−0.15; K2O: 0−0.06 (ratio is molar) Urbain SiO2-Al2O3-MO and SiO2-Al2O3-M2O mixtures (where MO and M2O represent divalent and monovalent oxides respectively) Riboud SiO2: 27%−56%; Al2O3: 0−12%; CaO: 8%−46%; Na2O: 0−22%; CaF2: 0−18% -
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