Abstract
Data are presented on the relationship between fineness of pulverized coal and combustion rate in the semi-industrial furnace, which is 515cm long, 25cm i.d. and with six windows of mica. Its burner is 16mm i.d. The main results are following;
(1) Elimination of the coarse particles, >200μ>, included about 3 or 4% in the original powdered coal with the residue of about 10-15% on the No. 170 sieve, results improvement of combustion rate of the order of 10%.
(2) When we burn only the superfine particles, <20μ, included about between 10 and 15% in the original, the temperature distribution in the furnace is relatively flat and the average value of the inner surface temperature of the wall is about between 6 and 9% high. But the maximum temperature in the furnace is all but the same as the original.
(3) Also as for the powder without the superfine, the effect of exclusion of the coarse is considerably evident.
