Process for operating a shaft kiln for burning limestone uses natural gas, heating oil or coal dust as fuel in two combustion periods

摘要

Process for operating a shaft kiln for burning limestone uses natural gas, heating oil or coal dust as fuel (BS) in two combustion periods. During the first combustion period, the fresh combustion air (Lp) in the preheating zone (VZA) of the shaft (A) is heated regeneratively countercurrently to 700-750o C. Only 60-70% of the total requirement for fuel is directly fed into the bulk material at the upper end of the combustion zone (BZA) of the shaft. Combustion in the combustion zone (BZA) of the shaft occurs stoichiometrically and the waste gases from the combustion zone enters the connecting channel (VK) at 900o C. 40-30% of the residual fuel (BSK) is fed to the bulk material to raise the waste gas temperature to 1250o C by combustion with the aid of cooling air (LK). The bulk material in the combustion zone of the further shaft (B) is deacidified countercurrently. The waste gas leaves the upper end of the combustion zone of the further shaft (B) at a temperature of over 900o C and flows through the preheating zone (VZB) of the shaft (B). These processes are repeated in a second combustion period.