OCR Text |
Show 1 7 So we suggest that ion radicals (CH20, H, etc.) in the flame reduce iron-oxide-Iayer of the steel strip. (1) Long and high speed flame Flame touch the steel strip widly, strongly and long time. (2) High temperature of the flame The combustion air is able to be preheated up to 500°C, so the high temperature of the flame produce many ion radicals. (3) Homogeneous flame The air ratio difference in the flame is small. (4) Good flame stability Ignition is very easy and safety. Air Center pipe COG - t:=::=====:::::~ __ --- ~======~=r==========================~====~======~~~ -: Fig. 27 Structure of SNM burner 3.6.3 Combustion characteristics Combustion . is conducted in a castable refractory furnace using a SNM burner of 70 x 103 kcal/h and 500°C air with coke oven gas. The distance between the burner and the plate is 300mm. (1) At 2% CO emission ratio of exhaust gas reducing effect is maximum, when the plate can be heated up to 900°C. (Fig. 28) (2) The higher the combustion load, the better the reducing effect. So, the combustion load of this burner must be high, if possible, over 60%. (Fig. 29) I - I I I I "..... P '-' 900- l:::.. © @ - "..... _ CO in exhaust gas: 2% G) P '-' ~ 0 @ @ - 900 ::s G) +0Gc~d.)l . BOO- 0 @ @ - +~:c=:ds' e @ @ @ ~ 800 G) G) 0.. +=' @ @ @ e 700 r- - G) G) +=' +=' cd - @ @ @ - Q) 700 0r-.I .. , +c=d' r-I 2 3 0.. CO in exhaust gas (%) - X ~ 0 0) - X 0 0 0) - X 0 @ ©> @ Clear than 1 raw A 0 0 ~ 0 Equal to raw - ~ 0 0 ~ ~ . .6. L~otxtildea tion Q). Week - ~ 0 ~ 0 ++=='' 4 oxidation 4) X Oxidation 1 I 1 I al 50 60 70 80 Fig. 28 Experimental result Combustion load (%) Fig. 29 Experimental result |