### I. After converting the six - effect sodium aluminate evaporator to a seven - effect evaporator, the temperature difference between effects decreases. Will this cause insufficient thermal power and unstable operation of the evaporator? **Answer**: After the six - effect evaporator at the Huayu Alumina Plant of Xinfa Group was converted to a seven - effect one, it has been operating smoothly for eight months. The operation of the seven - effect evaporator is no different from that of the previous six - effect evaporator. ### II. After converting the six - effect sodium aluminate evaporator to a seven - effect evaporator, the temperature difference between effects decreases, and the area of the evaporator for the same amount of water evaporation increases. Does the power of the circulation pump need to be increased? And one more transfer pump and one more circulation pump need to be added. Will the power consumption per unit of evaporated water increase? **Answer**: Compared with the integrated six - effect evaporator, the power consumption per unit of evaporated water of the new type of separate - type seven - effect evaporator will not increase; instead, it will slightly decrease. This is because the new type of separate - type seven - effect evaporator uses a new type of film distributor. Although the area of the evaporator has increased, the amount of feed liquid required for film formation has decreased. Therefore, the flow rate of the circulation pump will not increase. In addition, the overall height of the separate - type evaporator has decreased, and the heads of the circulation pump and the transfer pump have also decreased. Currently, the power consumption (installed capacity) of the domestic integrated six - effect evaporator is 7.16 KW/T of evaporated water, while the power consumption (installed capacity) of the separate - type seven - effect evaporator we designed is only 5.83 KW/T of evaporated water. ### III. Does the separate - type evaporator cover a much larger area than the integrated evaporator? **Answer**: The separate - type evaporator has a reasonable layout and good separation effect. The diameter of the separation chamber is slightly reduced. Therefore, the floor area of the seven - effect separate - type evaporator is only slightly larger than that of the six - effect integrated evaporator, with an increase of no more than 14%. For example, the floor area of a 220T/H six - effect integrated evaporator is 19.5m×63m, while that of a 220T/H seven - effect separate - type evaporator is 20m×70m. If both the separate - type and the integrated type are designed as seven - effect evaporators, there will be almost no difference in the floor area.