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准东煤中钠高温形态的化学动力学模拟

2017-10-17季杰强程乐鸣刘炎泉王勤辉骆仲泱

动力工程学报 2017年10期

季杰强, 程乐鸣, 刘炎泉, 王勤辉, 骆仲泱

(浙江大学 热能工程研究所,能源清洁利用国家重点实验室,杭州 310027)

准东煤中钠高温形态的化学动力学模拟

季杰强, 程乐鸣, 刘炎泉, 王勤辉, 骆仲泱

(浙江大学 热能工程研究所,能源清洁利用国家重点实验室,杭州 310027)

采用化学动力学软件Chemkin对碱金属含量高的准东煤在燃烧过程中气相钠的高温形态分布进行模拟计算,将模型计算结果与文献中的试验结果进行对比,研究了温度、过量空气系数α和压力对碱金属钠在高温下形态分布的影响,并对含钠气相产物进行了敏感性分析. 结果表明:计算结果与试验结果一致,验证了该模型的正确性;温度对含钠气相产物的转化有很大影响;当α<1时,含钠气相产物的组分分布受α的影响较大;压力对含钠气相产物物质的量分数的影响较小.

准东煤; 钠形态; 化学动力学; 敏感性; 模拟

Abstract: Chemical kinetics software Chemkin was applied to perform analog calculation on morphology distribution of gas-phase sodium at high temperatures in Zhundong coal with high alkali content during combustion process, and the calculation results were subsequently compared with reference data, so as to study the effects of following factors on the distribution of high-temperature morphology of alkali sodium, such as the temperature, excess air coefficient (α) and pressure, etc., and to analyze the sensitivity of relevant products. Results show that the calculation results agree well with actual measurements, proving the model to be correct; temperature significantly influences the conversion of sodium-containing gas-phase products; the component distribution of sodium-containing gas-phase products is remarkably influenced byαin the case ofα<1, which is slightly influenced by pressure.

Key words: Zhundong coal; sodium morphology; chemical kinetics; sensitivity; simulation

准东煤田发现于2005年,其蕴含的煤炭资源非常丰富,预测储量可达3.9×1011t[1],占新疆煤炭储量(2.19×1012t)的17%~18%,占全国煤炭储量(5×1012~6×1012t)的7%~8%. 准东煤的煤质较好,水分和挥发分含量较高,灰分和硫含量较低,应用前景非常广阔. 然而研究表明,准东煤中钠、钾等碱金属含量偏高,国内传统用煤中钠的质量分数一般在1%~2%(以灰分计),而准东煤中钠的质量分数一般在5%以上(以灰分计).燃用含高碱金属和碱土金属的煤会出现结渣、沾污、积灰和腐蚀等各种问题,严重影响锅炉的正常运行. Wang等[2]认为准东煤在燃烧过程中析出的碱金属和碱土金属化合物(NaCl、Na2SO4、CaSO4和K2SO4)[3]先在受热面附近沉积,随后部分硅铝酸盐被初始沉积层捕获,这是沾污……

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