飞灰残碳量对除尘器性能影响规律

Effect of residual carbon on precipitator performance

  • 摘要: 燃煤工业锅炉应用单一布袋除尘器已难以满足愈发严格的排放标准,电袋除尘器是实现燃 煤工业锅炉超低排放的选择之一。 基于耦合电袋除尘器实验平台,研究了残碳量对飞灰特性及布 袋除尘器和电袋除尘器除尘性能、运行情况及能耗等的影响,结果表明,堆积密度随飞灰残碳量降 低而增大,残碳量高于 18.18% 时增速较慢,低于 18.18% 时增速较快。 与布袋除尘器相比,电袋除 尘器出口总尘质量浓度和不同粒径颗粒物质量浓度均降低,总尘脱除效率和分级脱除效率均提高, 喷吹周期延长,喷吹压降最低值普遍降低,总能耗均降低,并且残碳量越低,除尘性能越好。 布袋除 尘器对不同残碳量飞灰有不同穿透窗口,脱除效率随飞灰残碳量降低而提高,而电袋除尘器对残碳 量低于 18.18% 的飞灰无明显穿透窗口。 两除尘器喷吹周期均随着喷吹次数增加而减小,压降最 低值随着喷吹次数增加而升高。 电袋除尘器对 4 种飞灰的平均喷吹周期分别是布袋除尘器的 3.27 倍、4.27 倍、4.91 倍和 1.92 倍,并且随着飞灰残碳量的降低,布袋除尘器的喷吹周期延长,压降最低 值减小,总能耗先减后增,电袋除尘器的喷吹周期则先延长后缩短,压降最低值先减后增,总能耗先 增后减,布袋压降是布袋除尘器和电袋除尘器总能耗的主要因素。 总体而言,电袋除尘器在除尘性 能、长周期运行和能耗等方面均优于布袋除尘器,是燃煤工业锅炉实现超低排放的有效途径之一。

     

    Abstract: Hybrid electrostatic precipitator is one of prospective devices for ultra⁃low emissions in coal⁃fired industrial boilers because a single bag filter has been difficult to meet stricter emission standards. An experiment has been car⁃ ried out based on the coupling electric bag filter experimental system to investigate the effect of carbon residue on par⁃ ticle characteristics,dust removal performance,operating conditions and energy consumption of the bag filters and hy⁃ brid electrostatic precipitators. The results show that the bulk density increases slowly and then increases sharply as the carbon residue increases more than 18.18%. Compared to the bag filter,the total and grade dust mass concentrations at the outlet of hybrid electrostatic precipitators are lower, the total and grade dust removal efficiencies are higher,the blowing cycles are extended,the minimum pressure drop is reduced,and the total energy consumption is decreased. Moreover,dust removal performance is better with lower carbon residue of fly ash. The penetration win⁃ dows of the bag filter distribute at different particle sizes with different carbon residues. Also the hybrid electrostatics has no obvious penetration window expected for the fly ash with residual carbon less than 18.18%. The blowing cycles of both dust collectors decrease and the minimum pressure drop of both dust collectors increases as the number of blows increases. An average blowing cycle of the hybrid electrostatic precipitators for four kinds of fly ash is 3.27,4.27,4.91 and 1.92 times of the fiber filter,respectively. With carbon residue decreasing,the blowing cy⁃ cle of the fiber filter extends and the minimum pressure drop decreases,the blowing cycle of hybrid electrostatic pre⁃ cipitators first extends and then shortens and the minimum pressure drop decreases firstly and then increases. In addi⁃ tion,with the residual carbon reduction,the total energy consumption first decreases and then increases for the bag fil⁃ ter and first decreases and then increases for the hybrid electrostatic precipitators. Bag pressure drop is the main factor in the total energy consumption of the bag filters and hybrid electrostatic precipitators. Overall,the hybrid electrostatic precipitator is better than the bag filter in terms of dust removal performance,long⁃cycle operation and energy con⁃ sumption. Therefore,the hybrid electrostatic precipitator is one of the prospective ways to achieve ultra⁃low emissions for coal⁃fired industrial boilers.

     

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