Title: Effects of preignition on pulverized-coal combustion. Second quarterly report, 1 January 1981-31 March 1981. [Above 800K]
Abstract: The technical effort on pore structure optimization is complete. The basic conclusion is that particle size and porosity are the most important physical properties of char when considering char oxidation above 800K. The distribution of porosity with pore size is of secondary importance. The internal surface area and pore aspect ratio have no significant influence on char oxidation above 800K. The apparatus for the bench scale pore evolution experiments has been constructed. Coal samples will be heated at various rates to various final temperatures and the pore structure of the remaining char will be measured. Preliminary data have been analyzed using N/sub 2/ and CO/sub 2/ adsorption, Hg porosimetry and Hg and He densities. In future studies, the CO/sub 2/ and N/sub 2/ adsorption will be omitted as they have not yielded any surprising empirical results and do not offer any information which is useful to the theory of a tailored pore structure for enhanced char reactivity. The Hg and He densities are important as they yield the char pososity and the Hg porosimetry is important as it yields the size distribution of the large pores which control char oxidation. Both the He pycnometer and Hg porosimeter have been purchased. All future experiments and char analyses will be performed in-house. The theory of pore evolution has been initiated. A statistical description of the pore tree has been developed.