基于大型电厂配煤方案的颗粒物生成实验研究

燃煤电厂常采用混煤燃烧，为降低颗粒物的排放，需选择合适的配煤方案。基于国内某大型电厂常用的配煤方案，在实验室条件下进行了颗粒物生成实验研究。选择山西煤（SX）、澳洲煤（AZ）、伊泰煤（YT）3种烟煤和1种印尼褐煤（YN），配煤方案为SX∶YN=3∶2，AZ∶YN=3∶2和AZ∶YT=3∶2（质量比）。在沉降炉中进行了原煤及混煤的燃烧实验，实验温度均为1 300 ℃，生成的颗粒物被低压撞击器所收集。实验结果表明，混煤及原煤燃烧生成的颗粒物具有相似的质量粒径分布；在所研究的条件下，混煤燃烧生成的颗粒物均少于由原煤燃烧颗粒物所得的计算值，不同煤中矿物质之间的交互作用是导致混煤燃烧颗粒物减少的主要原因；在所关注的3种配煤方案中，以混煤SX∶YN=3∶2燃烧生成的颗粒物总量最少，因此为最优配煤方案。

Experimental investigation on particle formation in combustion of coal blends based on a large-scale power plant scheme

Coal-fired boilers normally burn blended coal.For particle reduction，coal blending schemes should be optimized.Based on the coal blending schemes in a large-scale power plant，the combustion experiments of raw coals and their blends were carried out on a drop tube furnace at 1 300 ℃.Four types of raw coals，including three bituminous coals (SX，AZ，and YT) and one lignite (YN)，and three coal blends (i.e.SX∶YN=3∶2，AZ∶YN=3∶2 and AZ∶YT=3∶2) were tested.Combustion particles were collected by a low pressure impactor and their formation characteristics were investigated.The results show that the particle mass size distributions for all cases are similar.Under the conditions investigated，the blended coal combustion produces less particulate matter compared to the value calculated based on the data of corresponding raw coals.It is due to the interactions between minerals from different type of coals.Among the three blending schemes，SX∶YN=3∶2 produces the least particulate matter，and thus it is the best choice for power plant to reduce particle emissions.