Mathematical modelling and numerical optimization of particle heating process in copper flash furnace
(1. School of Energy Science and Engineering, Central South University, Changsha 410083, China;
2. Hunan First Normal University, Changsha 410205, China)
2. Hunan First Normal University, Changsha 410205, China)
Abstract: A mathematical model of the particle heating process in the reaction shaft of flash smelting furnace was established and the calculation was performed. The results indicate that radiation plays a significant role in the heat transfer process within the first 0.6 m in the upper part of the reaction shaft, whilst the convection is dominant in the area below 0.6 m for the particle heating. In order to accelerate the particle ignition, it is necessary to enhance the convection, thus to speed up the particle heating. A high-speed preheated oxygen jet technology was then suggested to replace the nature gas combustion in the flash furnace, aiming to create a lateral disturbance in the gaseous phase around the particles, so as to achieve a slip velocity between the two phases and a high convective heat transfer coefficient. Numerical simulation was carried out for the cases with the high-speed oxygen jet and the normal nature gas burners. The results show that with the high-speed jet technology, particles are heated up more rapidly and ignited much earlier, especially within the area of the radial range of R=0.3-0.6 m. As a result, a more efficient smelting process can be achieved under the same operational condition.
Key words: flash smelting process; particle heating; mathematical model; high-speed jet; numerical simulation