%0 Journal Article
%T 燃煤机组催化剂表面积灰板结层多重分形分析            -
%A 冯延林
%A 卢程
%A 宋健
%A 宋权斌
%A 张巍
%A 邓伟力
%A 陈冬林
%A 龚蔚成
%J 洁净煤技术
%D 2019
%X 燃煤电站烟气中的飞灰在SCR催化剂表面沉积板结形成强垢是导致催化剂失活的重要原因,为及时清理催化剂表面强垢层,通常采用超声共振结合蒸汽吹扫将强垢去除,然而由于燃煤飞灰在催化剂表面的沉积板结使得强垢层形成较为稳定,导致现场高能耗操作下清灰效果不明显。为更好地研究飞灰在催化剂表面沉积板结对强垢形成的影响,借助现场小修期和SCR改造项目热态性能试验将不锈钢采样盘布置在3层催化剂层的迎风面进行采样,将3层SCR催化剂垢层样品采用原子力显微镜(AFM)进行表征测试,通过设置合适的阈值采用Matlab图形处理得到黑白二值图,并通过信息熵法获得盒子尺寸来分析多重分形标度区间的影响。结果表明,随着烟气的流程方向板结层的高程分区逐渐趋于碎片化,沉积飞灰粒度逐渐趋于均匀化,并随烟气流程的增加多重分形参数具有标度不变性;同时关联分形维数D2随着烟气流程的增加逐渐与Hausdorff分形维数D0接近;根据加权矩随变特性还发现板结层微观颗粒会随烟气流程的增加逐渐由疏松不均性演变为致密均匀性;由3层板结层多重分形谱对称性发现,随着烟气流程的延长,催化剂表面垢层多重分形谱宽度Δα明显增加,相应垢层表面粗糙度逐渐增加,且垢层表面奇异峰分布更加明显,催化剂表面飞灰板结形成垢层的主导因素主要源于小颗粒、小高程的概率分布点。研究表明,随着烟气流程的增加,催化剂表面垢层的多重分形特征明显,沉积飞灰颗粒粒度变小,板结层的均匀性增加,微观拓扑表面的高程聚类特征消失,为超声波共振与蒸汽吹扫等现场清灰操作提供理论依据。 The fly ash in the flue gas of coal-fired power station deposits a strong scale on the surface of the SCR catalyst,which is an important reason of catalyst deactivation.The ultrasonic resonance combined with steam purging method is usually used to clean the strong scale layer on the catalyst surface in time,However,due to the deposition of coal-fired fly ash on the surface of the catalyst,the formation of the strong scale layer is relatively stable,which results in the effect of ash removal under high-energy operation in the field not obvious.To better study the influence of fly ash deposition and agglomeration on the surface of the catalyst on the formation of strong scale,the stainless steel sampling tray was placed on the windward side of the three-layer catalyst layer for sampling by means of the field minor repair period and the thermal performance test of the SCR retrofit project.The samples of the three-layer SCR catalyst scale were characterized by atomic force microscopy (AFM).The black and white binary images were obtained by Matlab pattern processing by setting appropriate threshold values,and the box size was obtained by information entropy method to analyze the influence of multi-fractal scale interval.The results show that as the elevation zone of the stratification layer of the flue gas gradually becomes fragmented,the granularity of the deposited fly ash gradually becomes uniform,and the multi-fractal parameters have scale invariance with the increase of the flue gas flow.Meanwhile,the associated fractal dimension D2 gradually closes to the Hausdorff fractal dimension D0 with the increase of the flue gas flow.According to the variation property of weighted moment,it is found that the microscopic particles of the slab layer gradually change from loose non-uniformity to density uniformity with the increase of the flue gas flow.According to the multi-fractal spectrum symmetry of the three-layer slab
%K SCR催化剂
%K 表面垢层
%K 多重分形谱
%K 信息熵 SCR catalyst
%K surface scaling layer
%K multifractal spectrum
%K information entropy
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