A 1/4 full 3D computer model of 160 kA aluminum reduction cell during coke preheating was built by using finite element analysis
software ANSYS.The simulation on three typical kinds of cathode carbon blocks(semi-graphitic,semi-graphatizied and graphatizied) under the same preheating conditions was carried out.The results show that,because the electric and thermal conductivities of the three kinds of blocks increase in order the temperature distribution of the cathode becomes even in order;compared with that of the first kind(the semi-graphitic),the maximum temperature differences in blocks of the last two(the semi-graphatizied and the graphatizied) are decreased by 133℃ and 232 ℃,respectively;the average temperatures on block surface are increased by 34℃ and 57 ℃,respectively;the average temperatures in the circumjacent paste are increased by 77℃ and 126 ℃;the proportion of block surface with temperature higher than 900℃ increases from 52.4% to 63.0% and 70.5%,respectively;but the preheating time with the same preheating(end-point) increases from(96) h to(132) h and(205 h,) respectively. When the coke bed thickness increases from 20 h to 30 mm,the preheating time with the kind of the graphatizied is reduced from 205 h to 90 h,and although this measure influences the preheating effect negatively,the preheating effect is still much better than that corresponding to other two kinds of carbon blocks preheated under the condition of 20 mm coke bed.