Effect Of Mineral Characteristics On Particulate Matter Emission During Pulverised Coal Combustion

Coal is a kind of non-renewable and nongreen fuel; it takes a large share in human energy consumption. China is a huge energy consumption country that lacks of resource, as well as oil and gas, coal takes an extremely important role in our energy consumption. Atmosphere pollution from coal combustion will cause global harm; it will endanger the subsistence and development of human being. Particulate matter from coal combustion, especially the submicron particulate matter (PM₁), can suspend in the atmosphere for a long time and many harmful heavy metal elements could easily condense on its surface; meanwhile, PM could cause the decrease of atmosphere visibility, acid rain, climate change, ozonosphere destroy and so on. Therefore, the research on formation mechanism and emission characteristics of PM₁ from coal combustion is meaningful.This paper first analyzes the formation mechanism and emission characteristics of PM₁ from coal combustion in theory; then it gets low, medium and high density coal by using the floatation method to Liupanshui bituminous, and it gets small, medium and big size coal by using the sieving method to medium and high density coal above. Then, CCSEM is used to analyze the mineral distribution characteristics in the coals above. The CCSEM results show that the weight of included minerals and excluded minerals in the original coal are almost the same; the low-density coal mainly includes included minerals; the high-density coals mainly include excluded minerals; the percent of included minerals and excluded minerals in medium-density coals are between the low-density and high-density coal. What's more, low-density coal mainly includes included minerals with small size; high-density coals mainly include excluded minerals with big size; medium-density and small-size coal mainly includes excluded minerals with small size; medium-density, medium-size and big-size coals mainly include included minerals with big size.Then, some drop tube furnace combustion experiments are done with the coals above for the purpose of research on emission characteristics of PM₁. The experimental results show that the amount of PM₁ emission decreases while the coal density increases, that's mainly because of included minerals, the more the included minerals are, the more the PM₁ would form. For the medium-density coals combustion, the amount of PM₁ emission decreases while the coal size increases. For the high-density coals combustion, the amount of PM₁ emission increases while the coal size increases, that's mainly because there are lots of pyrites in high-density coals. The amount of PM₁ emission is the smallest in original coal combustion except the high-density and small-size coal, that's mainly because the mineral interactions decrease after floatation and sieving.