Direct observations of single particle fragmentation in the early stages of combustion under dry and wet conventional and oxy-fuel conditions |
| |
Authors: | Miriam Rabaçal Renan B Kops Fernando M Pereira Mário Costa |
| |
Institution: | 1. Mechanical Engineering Department, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal;2. Mechanical Engineering Department, Federal University of Rio Grande do Sul, Porto Alegre, Brazil |
| |
Abstract: | This article investigates the single particle fragmentation of three solid fuels in the early stages of combustion under dry and wet conventional and oxy-fuel conditions. The three solid fuels studied were a low rank sub-bituminous Colombian coal, a low-rank/high-ash sub-bituminous Brazilian coal, and a charcoal residue from black acacia. Particles, with size in the range 125–150 µm, were burned in a drop tube furnace with a constant wall temperature of 1475?K, under six different mixtures of O2/N2/CO2/H2O, which allowed simulating dry and wet conventional and oxy-fuel combustion conditions. A high-speed camera was used to record the fragmentation process during the early stages of combustion and the collected images were treated to characterize the fragmentation mode, probability and time. The observed fragmentation modes are characterized by the occurrence of exfoliation, radial fragmentation or a combination of both. The results disclose that the fragmentation mode is strongly affected by the fuel type, but less affected by the atmosphere; the fragmentation probability is strongly affected by both the fuel type and the atmosphere; and, finally, fragmentation in air occurs significantly dispersed after ignition, but it tends to cluster closer to the ignition under simulated oxy-fuel conditions. |
| |
Keywords: | Solid fuels Single particle Drop tube furnace Oxy-fuel combustion Fragmentation |
本文献已被 ScienceDirect 等数据库收录! |
|