The project of "Research and Development of the Seven-effect Two-stage Energy-saving Evaporator", jointly completed by Henan Jiuye Chemical Equipment Co., Ltd., Xinfagroup Co., Ltd., and Zhengzhou Research Institute of Chinalco Corporation, has for the first time achieved seven-effect two-stage continuous falling film evaporation in the alumina industry at home and abroad, and has been successfully applied in Xinfagroup. According to Ju Lirang, the general project director and the general manager of Henan Jiuye Chemical Equipment Co., Ltd., the developed two-stage continuous evaporation technology has greatly reduced the consumption of new steam; the design of the separate layout of the heating chamber and the separation chamber has been innovated, achieving sufficient vapor-liquid separation, pure evaporation condensed water, which can all be used as soft water for boilers; the developed new type of film distributor ensures that the inner wall of the heating tube does not have dry film or broken film, stably maintaining a high heat transfer efficiency, and realizing the overall integration of the seven-effect two-stage evaporation technology. It is reported that currently, the six-effect falling film evaporator is commonly used in the alumina industry at home and abroad, and most of its steam consumption is above 0.3t steam per ton of water, with the best level being 0.28t steam per ton of water. In the transformation of the Chiping alumina evaporation system of Xinfagroup, this project applied a set of 220t/h seven-effect falling film evaporator. When the temperature of the original evaporation solution is 70℃, the steam consumption reaches 0.22t steam per ton of water, and all the condensed water can be used for boilers. Compared with the six-effect evaporator before the transformation, the steam consumption is reduced by 0.08t steam per ton of water, saving 150,000 tons of steam annually; compared with the best domestic level, the steam consumption is reduced by 0.06t steam per ton of water, saving 110,000 tons of steam annually, with outstanding energy conservation and emission reduction effects. This technology and equipment have a good energy-saving demonstration effect and can be comprehensively promoted in the alumina industry, saving 20 to 30 million tons of steam annually and creating an economic benefit value of 3.6 billion yuan. At the same time, this project can also be popularized and applied in industries such as chemical engineering, with very significant economic and social benefits.