Characteristics of microstructures and gasification reactivity of co-pyrolysis coal char with oily sludge and blended coal
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摘要: 以含油污泥与配合煤为原料在850-1150 ℃热解制得焦样, 采用N2吸附-脱附和X射线衍射(XRD)分析煤焦孔隙结构及碳微晶结构, 并运用热重分析(TGA)考察热解温度和含油污泥添加量对煤焦气化反应活性的影响。结果表明, 提高热解温度和添加含油污泥能促进煤焦形成更加丰富的孔隙结构, 强化煤焦-CO2气化反应接触并抑制煤焦石墨化进程, 从而提高煤焦气化反应活性;然而, 热解温度过高或添加油泥量过多则会致使煤焦结构致密或孔隙堵塞, 气化反应活性反而降低。Abstract: Char samples were prepared by pyrolysis of oily sludge and blended coal at 850-1150 ℃. The pore structure and crystallite structure of chars were analyzed by N2 adsorption-desorption and X-ray diffraction (XRD). Effects of pyrolysis temperature and amount of oily sludge on gasification reactivity of the char was investigated by thermogravimetric analysis (TGA). The results show that increasing pyrolysis temperature and adding oily sludge can promote the formation of more abundant pore structure of chars, strengthen chars-CO2 gasification reaction and inhibit graphitization process of chars, thus improving gasification reactivity of the chars. However, too high pyrolysis temperature or too much sludge will also result in dense structure or pore plugging of coal char, and reduce gasification reactivity of the char.
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Key words:
- oily sludge /
- co-pyrolysis /
- char /
- microstructures /
- gasification reactivity
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图 1 实验装置流程示意图
Figure 1 A schematic diagram of the experimental apparatus
1: N2 cylinder; 2: mass flowmeter; 3: one-way valve; 4: gas preheater; 5: high temperature reactor; 6: condenser; 7: tar tank; 8: acetone washing bottle; 9: ice bath; 10: indicator bottle; 11: wet flowmeter; 12: gas bag; 13: gas chromatography
表 1 样品的工业分析和元素分析
Table 1 Proximate and ultimate analyses of samples
Sample Proximate analysiswad/% Ultimate analysisw/% M A V FC Cad Had Nad Sc, ad Oad CYM 4.77 5.69 31.40 58.14 69.84 5.18 0.78 0.87 12.87 QM 2.12 7.42 31.89 58.57 71.42 4.94 0.86 0.94 12.3 JM 3.07 60.67 6.57 29.69 72.56 4.42 0.97 3.77 8.64 DOS(105 ℃) - 12.26 80.35 7.39 64.86 8.27 0.59 2.96 11.06 表 2 含油污泥灰组成的X射线荧光光谱分析
Table 2 Composition of solids in DOS measured by XRF
Sample Composition w/% Fe2O3 SiO2 CaO Al2O3 Na2 K2O ZnO SO3 TiO2 MgO MnO DOS 30.24 17.05 12.56 6.78 6.38 4.27 3.35 3.08 2.01 1.54 0.79 表 3 配合煤添加含油污泥制焦煤焦的孔隙结构特性
Table 3 Pore structure characteristics of char from pyrolysis of mixed coal loaded with oily sludge
Sample and pyrolysis temperature BET Atotal/(m2·g-1) Pore volume vtotal/(mL·g-1) Average aperture Da/nm char temperature t/℃ CQJ 850 51.204 0.0425 5.904 DOS3 57. 142 0.0487 5.517 DOS8 65.637 0.0512 4.246 DOS15 64.892 0.0503 4.231 CQJ 950 69.025 0.0472 5.036 DOS3 74.217 0.0517 4.819 DOS8 90.417 0.0585 4.587 DOS15 85.057 0.0551 4.425 CQJ 1050 81.015 0.0503 5.003 DOS3 104.223 0.0529 4.224 DOS8 115.453 0.0592 4.087 DOS15 108.012 0.0576 4.425 CQJ 1150 78.705 0.0473 4.891 DOS3 87.227 0.0498 4.224 DOS8 88.415 0.0517 4.087 DOS15 70.004 0.0509 4.425 表 4 煤焦样品的动力学参数
Table 4 Kinetic parameters of char samples
Sample CQJ DOS3 DOS8 DOS15 E/(kJ·mol-1) 263.22 237.04 164.02 246.42 A 20.07 18.52 12.25 20.43 -
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