Open AccessMECHANISMS AND OPTIMIZATION OF COAL COMBUSTION
Author(s) -
Kyriacos Zygourakis
Publication year - 2000
Language(s) - English
Resource type - Reports
DOI - 10.2172/789667
Subject(s) - char , combustion , pyrolysis , ignition system , particle (ecology) , process engineering , coal , materials science , swelling , transient (computer programming) , autoignition temperature , process (computing) , mechanics , biological system , computer science , environmental science , chemical engineering , waste management , composite material , chemistry , thermodynamics , engineering , geology , physics , oceanography , organic chemistry , biology , operating system
The completed research project has made some significant contributions that will help us meet the challenges outlined in the previous section. One of the major novelties of our experimental approach involves the application of video microscopy and digital image analysis to study important transient phenomena (like particle swelling and ignitions) occurring during coal pyrolysis and combustion. Image analysis was also used to analyze the macropore structure of chars, a dominant factor in determining char reactivity and ignition behavior at high temperatures where all the commercial processes operate. By combining advanced experimental techniques with mathematical modeling, we were able to achieve the main objectives of our project. More specifically: (1) We accurately quantified the effect of several important process conditions (like pyrolysis heating rate, particle size, heat treatment temperature and soak time) on the combustion behavior of chars. These measurements shed new light into the fundamental mechanisms of important transient processes like particle swelling and ignitions. (2) We developed and tested theoretical models that can predict the ignition behavior of char particles and their burn-off times at high temperatures where intraparticle diffusional limitations are very important