PROCESS AND APPARATUS FOR CALCINING CEMENT CLINKER WITH PRE-HEATING AND PRE-DECOMPOSITION AT HIGH SOLID-TO-GAS RATIO

摘要

Disclosed is a process for calcining a cement clinker with pre-heating and pre-decomposition at a high solid-to-gas ratio. During the firing of the cement clinker, the cement raw materials first exchange heat with heated flue gas in a pre-heater having a high solid-to-gas ratio, and then enter an outer circulation decomposition furnace having a high solid-to-gas ratio to complete the decomposition of carbonates in the cement raw material. The materials after decomposition enter a rotary kiln for calcination, and the sufficiently calcined materials enter a cooler for cooling so as to complete the calcination of cement clinker. The present invention uses a heat treatment apparatus with crossing material flows at a high solid-to-gas ratio to pre-heat the raw materials, and at the same time recycles the enthalpy in the waste flue gas efficiently; it employs the outer circulation decomposition furnace at a high solid-to-gas ratio to complete the decomposition of the pre-heated cement raw materials in a suspension form, reduces effectively the temperature of waste gas discharged by the system and the heat consumption per unit cement clinker, improves the thermal efficiency of the system, the apparent decomposition ratio of the materials entering the kiln, the production per unit volume of the decomposition furnace and of the rotary kiln, enhances the heat stability of the decomposition furnace, and simultaneously decreases the discharge of harmful gases, such as SO2, NOx, etc.