COMBUSTION AND GASIFICATION REACTION BEHA VIORS OF PLASTIC IN BLAST-FURNACE

In order to establish the plastic injection technology in the blast fu rnace, the behaviors of plastic pyrolysis, combustion and gasification reaction have been investigated with two kinds of model experiment; o ne is the vertical tower type reactor called the combustion model and the other is the blast furnace type reactor called the hot model. The combustion of plastic does not occur in the blast having the temperatu re of 1250 degrees C and the O-2 enrichment of O% in the blowpipe and tuyere. The combustion starts in the air over the temperature of 1550 degrees C, but the CO2 gasification does not occur at this temperature in the combustion model. The split of plastic occurs in the atmospher e over the temperature of 2000 degrees C in the raceway from 1000 simi lar to 2000 mu m to 200 mu m. The split plastic is burnt in the racewa y, the unburnt plastic is consumed and accumulated in the hot model an d it does not flow out of the top. The entering of plastic contained f ines into the deadman can be suppressed by injecting the plastic direc tly into the raceway through the tuyere or by keeping the distance of the lance tip from the tuyere nose as short as possible in case of the injection through the side of blowpipe. The plastic injection alone i s better than the mixing injection with pulverized coal in order to ma intain the permeability in the lower part of the hot model.