The Numerical Simulation And Optimization Study On The Carbon Roaster

Carbon electrode production belongs to the industrial energy in China and carbon calcination is one of important heat treatment process in the production process. It has huge potential to realize saving energy and reducing consumption on the structure and operation parameters optimization. Because of the complexity of the thermal process of carbon calcinations, it is of great significance to improve the baking furnace operating conditions, By using numerical simulation method to the thermal process of carbon calciner system research.Aiming at solving the problem such as temperature distribution of the block of carbon electrode and the long roasting cycle, the influences of the structure and operating parameters are studied on the carbon calcinations. The main work and conclusions are as follows:1) Based on a certain carbon plant room 12 down-draft type carbon roaster as the research object. Firstly, it is found that it is more than 69% of internal loss is exhaust losses, more than 69%, after doing the combustion test and heat balance analysis. Then we established the mathematical model of thermal process on the carbon calciner, based on the reasonable simplification of actual physical model and assumption. Besides, Based on the FLUENT software and the characteristics of carbon baking furnace roasting process, we established a thermal process simulation system on the carbon calciner by using the standard turbulence model, non premixed combustion model, radiation model P- 1, implements the furnace field coupling, and chemical reaction balance, through the calculation of pre PDF.2) It studied on the roaster velocity field, temperature field,concentration field, the carbon electrode heating curves and eventually roasting temperature distribution pattern in the initial conditions by the way of numerical simulation. The simulation results show that the high temperature of furnace smoke flow mainly to drop fire exit pressure direction, other area leading role within the furnace is less, so the performance for furnace fire is opposite bigger, on the contrary, the velocity and the other area of velocity is relatively small. At the same time, in a roasting cycle, carbon electrode piece of actual roasting heating rate lower than the target calcination temperature about 200 ℃,that large behind the target heating rate. In addition, carbon electrode block on the vertical temperature gradient is larger, carbon electrodetemperature gradually raised along the height direction, that makes carbon electrode block maximum temperature over 200 ℃.3) By the method of adding a branch at the bottom of the carbon electrode block,The temperature difference can effectively reduced in the vertical direction. The simulation results show that modified carbon electrode roasting temperature of time shorter, when reaches the same calcination temperature. That save for 15.35 hours and the equivalent of about 655 kg of standard coal saving.4) Based on the structure optimization on the fire, we explored the influence of the combustion air temperature and fire exit negative pressure and other factors on the temperature rate and the temperature uniformity of the carbon electrode. It is shows that the temperature of the carbon electrode was promoted, and its internal temperature decreases, and better uniformity following the increase of combustion air temperature. On the other hand, When negative pressure is about 3 Pa, we found that the fire passage for the average temperature is higher, and the carbon electrode block temperature is relatively uniform. Because of the sufficient oxygen, with the proper fuel combustion fully, and excess air coefficient can guarantee the fuel combustion rate is high, the state all the heat loss is reduced to the minimum at the same time.This is the optimal choice of the size of the negative pressure.