Effects of fine ash particles and alkali metals on ash deposition characteristics at the initial stage of ash deposition determined in 1.5 MWth pilot plant tests
Effects of fine ash particles and alkali metals on ash deposition characteristics at the initial stage of ash deposition determined in 1.5 MWth pilot plant tests
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DOI：
10.1016/j.fuel.2012.01.036
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发表时间：
2012-07
期刊：
影响因子：
7.4
通讯作者：
Miki Shimogori;Toshihiko Mine;Noriyuki Ohyatsu;Noboru Takarayama;Y. Matsumura
中科院分区：
文献类型：
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作者：
Miki Shimogori;Toshihiko Mine;Noriyuki Ohyatsu;Noboru Takarayama;Y. Matsumura
本研究的目的是评估细灰颗粒和碱金属对在灰沉积的初始阶段的热通量下降的影响，这在整个灰沉积过程中的传热特性具有显着的影响。为此，在1.5MW的中试装置上进行了一系列结渣试验。采用模拟锅炉水冷壁的高温区结渣探头，对四种烟煤和三种次烟煤的传热特性进行了实验研究。计算了通过结渣探头的热通量，并对每种煤的每单位重量分数的灰的热通量的降低率（dq/dt-灰）进行了比较。在每次测试运行后，对结渣探头上的沉积物进行取样和分析。分析结果表明，烟煤中小于10μm（R10 under）的粒级变化范围很大，从5 ~ 45 wt.%，而次烟煤的那些变化不大：从16到30 wt.%。在碱性组分方面，烟煤沉积物内层倾向于富集Al、Fe和Ca。在次烟煤的情况下，难熔化合物的Si，Al和Ti，碱金属化合物的Na，K，Fe和P。为了评估的影响因素的热通量的下降率在灰沉积的初始阶段定量，热通量数据（dq/dt灰）进行多元回归分析，使用以下参数：R10下，也Na 2 O和K2 O值在每个母煤。回归方程的计算结果与实验数据吻合较好。
The purpose of this study was to evaluate the effect of fine ash particles and alkali metals on the decreasing heat flux at the initial stages of ash deposition which has a significant effect on heat transfer characteristics during the whole ash deposition process. For this purpose, a series of slagging tests were conducted in a 1.5MWthpilot plant. The heat transfer characteristics of four bituminous and three sub-bituminous coals were studied using a slagging probe set in the high temperature zone simulating the water wall in actual boilers. The heat flux through a slagging probe was calculated and the decreasing rate of heat flux per unit weight fraction of ash (dq/dt-ash) was compared for each coal. Deposits on the slagging probe were sampled and analyzed after each test run. Analysis results showed that particle fractions with a diameter less than 10μm (R10under) of bituminous coals varied in wide range: from 5 to 45wt.%, while those of sub-bituminous coal did not change greatly: from 16 to 30wt.%. In terms of alkali components, the inner layer of deposits of bituminous coals tends to enrich Al, Fe and Ca. In the case of sub-bituminous coals, refractory compounds of Si, Al and Ti, alkali compounds of Na, K, Fe and P. To evaluate the influence of factors on the decreasing rate of heat flux at the initial stage of ash deposition quantitatively, a multiple regression analysis of heat flux data (dq/dt-ash) was performed using the following parameters: R10under, and also Na2O and K2O values in each parent coal. Calculation using a regression equation agreed well with experimental data.