I. After the six-effect evaporator for sodium aluminate is modified into a seven-effect evaporator, the temperature difference between the effects decreases. Will this lead to insufficient thermal power of the evaporator and unstable operation?

Answer: After the six-effect evaporator in Huayu Alumina Plant of Xinfa Group was modified into a seven-effect evaporator, it has been in operation for eight months and runs stably. The operation of the seven-effect evaporator is no different from that of the previous six-effect evaporator.

After the six-effect evaporator for sodium aluminate is modified into a seven-effect evaporator, the temperature difference between the effects decreases, and the area of the evaporator for the same amount of distilled water increases. Does the power of the circulation pump need to be increased? And one more feeding pump and one more circulation pump need to be added. Will the power consumption per unit of distilled water increase in this way?

Answer: Compared with the integrated six-effect evaporator, the power consumption per unit of distilled water of the new split-type seven-effect evaporator will not increase, and it may even decrease slightly. This is because the new split-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 instead. Therefore, the flow rate of the circulation pump will not increase. In addition, the overall height of the split-type evaporator has been reduced, and the head of the circulation pump and the feeding pump has been reduced. At present, the power consumption (installed capacity) of the six-effect integrated evaporator in China is 7.16 KW/T of distilled water, and the power consumption (installed capacity) of the split-type seven-effect evaporator designed by us is only 5.83 KW/T of distilled water.

III. Does the split-type evaporator occupy much more floor space than the integrated evaporator?

Answer: The split-type evaporator has a reasonable layout and good separation effect. The diameter of the separation chamber has been reduced. Therefore, the floor space occupied by the seven-effect split-type evaporator is slightly larger than that of the six-effect integrated evaporator, and it will not exceed 14%. For example, the floor space of the 220T/H six-effect integrated evaporator is 19.5m×63m, and the floor space of the 220T/H seven-effect split-type evaporator is 20m×70m. If both the split-type and the integrated type are made into seven-effect evaporators, there will be almost no change in the floor space.