Effect of raw material, moisture and high-temperature tertiary air on a coal gasifier for cement precalciation

This paper proposes a new method of pulverized coal gasification using high-temperature tertiary air in a cement precalciner, in which an external hanging gasifier is added nearby. A full-scale model is established and simulated for the entrained flow gasifier. During the gasification process, the global reaction mechanism is used to model the release and reactions of volatiles from pulverized coal, and a particle surface reaction model is employed to calculate the fixed carbon content. The mechanism by which reducing gas reacts with NO is also considered. The results of the velocity, temperature, gas composition, NO x emissions, calorific value, volatile conversion ratio and char burnout ratio, are achieved in the simulation. The results show that the volatile conversion ratios were close to 100%, and the carbon conversion ratios ranged from 27.97% to 62.76% among all the tested conditions. The concentrations of NO at the outlet of the gasifier were 109, 98, 75, 91, 87, 76, and 90 mg/m 3 separately in 7 conditions. These values are significantly lower than those of complete combustion. However, the addition of raw meal had the best temperature control effect, leading to a significant decrease in thermal NO x production and no side effects on the stability of the production line. • Pulverized coal gasification using high-temperature tertiary air in a gasifier was simulated. The results were compared with the experimental data. The feasibility of the model and the reliability of the algorithm were verified. • The change in the excess air coefficient, the addition of steam, and the addition of raw meal can all be used to control the temperature and protect the materials of the gasifier. • The concentrations of NO at the outlet of the gasifier were 109, 98, 75, 91, 87, 76, and 90 mg/m 3 separately in 7 conditions. These values are significantly lower than those of complete combustion (mostly around 800–900 mg/m 3 ).