OCR Text |
Show - 9 - 1.0,...----- --------------, 08 '"' 06 a d ~ 0.4 0.2 R/ Ro=O Reo=wdo/ v 0.01----.L.---.1---..I.....----'-------' o 10 1.0.,.----------------, 0.9 '"' 0.8 a IS .... :;: 0.7 0.6 0.6 0.0 0.2 R/ Ro=O ex = o. giReoPr 1/3 Reo=wdo/v 0.4 ex 0.6 0.8 1.0 Fig. 4 The effect of relative velocity on the diffusion limited total char combustion time, f(a,O). 10 0.8 a 0.6 a:: "- ~ § O. ~ 0.2 o ~.o 0.2 0.4 0.6 R/ Ro Fig. 5. Values of function f(a,R/R o). 0 0 . 1 0 .2 0 .5 1 2 ex 5 10 0.8 1.0 The coal particle combustion with high Reynolds number is considered in /11/ and with oscillating flow in /12/. The total combustion time and the dependence of the instantaneous particle radius on time can be calculated as the sum of the combustion time with infinite fast chemical reaction and the combustion time with infinite fast diffusion t t t h t = Ro-R = d + c were c ~ p ( 1 5 ) The rate of the chemical reaction is, for example, of the A -E/RT form kc = e . The transient particle temperature during the char canbustion is calculated from the thermal balance 31 PCRddTt + h ( T-Tef ) + EO (T'+ -Tr'+ ) + p~HddRt = ° ( 1 6) |