【Ten Years of Rapid Development in Chemical Equipment】The 100% domestically produced perfluorinated ion exchange membranes of Shandong Dongyue Group from 1969 to 2010

Achieving domestic production of perfluorinated ion membranes for the chlor-alkali industry has always been a shared goal of ** and the chlor-alkali sector; it was once designated as the \"Number One Project\" by the former Ministry of Chemical Industry. In 2009, with the support of the 10th Five-Year Plan’s **863 Program** and the 11th and 12th Five-Year Plans’ science and technology support programs, Shandong Dongyue Group and Shanghai Jiao Tong University, through 8 years of joint research, successfully overcame a series of key technical challenges ranging from raw materials and monomers to polymerization and the production of membrane products. They resolved related theoretical, technical, equipment, and engineering issues, developed a technical system with independent intellectual property rights, and built a continuous production line for perfluorosulfonic/perfluorocarboxylic/reinforced composite ion membranes with a width of 1.35 meters. All technical specifications of the domestically produced ion exchange membranes have reached the level of international counterparts, and they have been successfully applied in 10,000-ton-scale chlor-alkali production plants. 　　 Due to the limited number of monopolar electrolyzer units suitable for the first-generation domestic ion exchange membranes, in 2012, Dongyue Group developed a second-generation high-performance domestic ion exchange membrane suitable for high current densities by creating 3D micro-channel structures and reducing the thickness of the membrane layer. The second-generation ion membrane offers better impurity tolerance while reducing the cell voltage. In 2014, they carried out various research and development projects as well as equipment upgrades, including resin optimization, mesh fabric improvement, structural innovation, and equipment modification, resulting in domestically produced ion membranes that are suitable for electrolysis processes with extremely high current densities, possess superior mechanical properties, and are comparable in performance to third-generation ion membranes from abroad. At present, through the upgrading of its membrane-making machinery for ion exchange membranes, Dongyue Group has been able to cover all types of ion exchange membrane electrolyzers.

Promoting the upgrading of the chlor-alkali industry: Domestic ion exchange membranes have demonstrated good practical performance. In 2010, the DF988 ion membrane operated successfully for 3,600 hours in the industrialization test facility for ion membrane electrolysis technology at Lanxing (Beijing) Chemical Machinery Co., Ltd., achieving initial success. Subsequently, the domestically produced ion exchange membranes were tested in the chlor-alkali plants of nearly 20 domestic and foreign companies, including Shanghai Chlor-Alkali Chemical Co., Ltd., Zhongyan Changzhou Chemical Co., Ltd., Evonik Sanzheng Fine Chemicals Co., Ltd., Qingdao Haijing Chemical Group Co., Ltd., and Thailand’s SiamPVC Chemical Company, thereby generating important data on the industrial application of such membranes. 　　 Furthermore, the successful development of domestically produced ion exchange membranes has also promoted the widespread adoption of the ion exchange membrane process for caustic soda production. At present, China has basically completed the full replacement of ion-exchange membrane technology, achieving industrial upgrading in the chlor-alkali industry. According to statistics, from 2010 to 2017, approximately 7.2 million tons of caustic soda production capacity using the diaphragm process was phased out, resulting in annual energy savings of around 2.2 million tons of standard coal. At the same time, the use of domestically produced ion exchange membranes has put significant pressure on imported ones. As a result, foreign companies have accelerated their research and development efforts to introduce products with lower energy consumption and more competitive prices. This has further reduced the costs associated with industrial upgrading and operation in China’s chlor-alkali industry, thereby enhancing the industry’s overall competitiveness.

On May 26, 2019, the China Petroleum and Chemical Industry Federation organized experts to hold an appraisal meeting at Dongyue Group’s Intelligent Control Center for two scientific and technological achievements of the **Key Laboratory of Fluorine-Containing Functional Film Materials: the \"high electric density and low cell voltage chlor-alkali ion membrane\" and the development of \"ethylene-tetrafluoroethylene copolymer resin (ETFE)\”. The appraisal committee for this evaluation was composed of 7 experts, including Academician Yang Wantai from Beijing University of Chemical Technology, Professor Guo Baohua from Tsinghua University, and Secretary-General Zhang Wenlei from the China Chlor-Alkali Industry Association. In accordance with the procedures of the appraisal meeting, the experts present unanimously recommended Academician Yang Wantai to serve as the chairperson, and Professor Guo Baohua to serve as the vice-chairperson. The experts present agreed that the overall technology of both achievements has reached an internationally advanced level; in particular, the core technical parameter of the chlor-alkali membrane, namely the cell voltage, is at an internationally leading level. They approved the approval of these achievements. The chlor-alkali industry is an important foundational sector of China’s national economy. By 2018, China’s total production capacity for chlorine and caustic soda had reached 42.59 million tons + 37.80 million tons = 80.39 million tons, with the ion-exchange membrane process accounting for approximately 99.4% of this production. The output of caustic soda reached 34.20 million tons, ranking first in the world. The core equipment in the chlor-alkali industry is the electrolyzer, and the key material for the electrolyzer is the chlor-alkali ion exchange membrane. Currently, the domestically produced DF2807 chlor-alkali ion exchange membrane has been industrialized and is capable of meeting the requirements of all types of chlor-alkali membrane electrolyzers worldwide. The successful application of domestically produced perfluorinated ion exchange membranes can accelerate the transformation and upgrading of China’s chlor-alkali industry, and help Chinese chlor-alkali companies save over 5 billion yuan in electricity costs each year, bringing significant economic benefits. At the same time, it **enhanced the overall technical level of China’s fluorine materials industry and completely eliminated the bottlenecks that hindered the development of China’s chlor-alkali industry.

The development of China’s chlor-alkali industry has always been closely linked to the growth of the national economy. Over the 40 years since the reform and opening up, China’s annual production of caustic soda and polyvinyl chloride (PVC) has increased from less than 2 million tons initially to tens of millions of tons today. The country has become the world’s largest producer and consumer of chlor-alkali products. Its technical capabilities have seen significant improvements, industrial concentration has continued to rise, and the concepts of safety and environmental protection have taken root among the population. Thus, a remarkable journey from a small-scale operation to a major industry has been achieved. 　　According to statistics from the China Chlor-Alkali Industry Association, there are currently 160 caustic soda production enterprises in China, with a total annual production capacity of 41.02 million tons, accounting for 44% of the world’s total capacity. There are 75 PVC production enterprises, with a total annual production capacity of 24.06 million tons, representing 41% of the world’s total capacity. In 2017, China’s caustic soda production reached 33.65 million tons, which is 20.4 times that of 1978 (1.648 million tons), representing an average annual growth rate of 8.04%. In the same year, PVC production amounted to 17.9 million tons, 70 times higher than in 1978 (256,000 tons), with an average annual growth rate of 11.51%. After 40 years of development, China’s chlor-alkali industry leads the world in terms of the production volume of its two main products: caustic soda and PVC. The production capacity for chlorine-consuming products has grown rapidly, with the output of some of these products also ranking among the highest in the world. Among them, PVC has become the largest organic chlorine product in China, accounting for about 40% of the country’s total chlorine production volume; it is the main product used to regulate the balance between alkalis and chlorine. 　　The annual apparent consumption of caustic soda increased from 1.75 million tons in 1978 to 32.14 million tons in 2017, accounting for over 30% of the global consumption market. PVC has also expanded into a wide range of consumer applications such as profiles, pipes, films, and sheets; by 2017, its apparent consumption volume had reached 17.71 million tons. 　　Driven by technological progress and market forces, the industrial product chain of China’s chlor-alkali industry is becoming increasingly diverse. According to rough estimates, China’s chlor-alkali enterprises are currently capable of producing over 200 chlorine-consuming products. In addition to PVC, which accounts for the largest share, there are more than a dozen major categories of products, including epoxides, methyl chlorides, chlorinated polymers, phosgene derivatives, chlorinated aromatics, as well as fine chemicals. Among them, PVC, paste resins, chlorinated paraffins, epichlorohydrin, methyl chlorides, propylene oxide, MDI/TDI, etc. have relatively large production capacities. 　　In terms of industrial layout, chlor-alkali industry belts in the eastern and western regions are gradually taking shape, resulting in a clearer spatial distribution of these industries. The eastern provinces have a long history in the chlor-alkali industry and are also the main consumer markets for chlor-alkali products. Through years of development, the chlor-alkali industry in the eastern region has explored new cross-sectoral development models that integrate it with industries such as chemical new materials, fluorine chemicals, fine chemicals, and pesticides. The chlor-alkali industry in the western region began to develop rapidly only after the turn of the new century. By leveraging its resource advantages to build large-scale, integrated \"coal-electricity-salt-chemical\" projects, this has become a key characteristic of the development of the chlor-alkali industry in that region. Moreover, the chlor-alkali enterprises in the western region are all local leaders, playing a significant role in promoting the local economic and social development. 　　According to a responsible official from the China Chlor-Alkali Industry Association, over the past 40 years, thanks to technological advancements, the energy and resource consumption in the chlor-alkali industry has continued to decline, while the level of comprehensive resource utilization, technical equipment, and clean production has improved further. 　　Following Germany and Japan, our country has become the third in the world to be able to produce complete sets of equipment for ion membrane electrolyzers; the number of domestically produced ion membrane electrolyzer units in use accounts for over 20% of the total worldwide. Devices using the caustic soda diaphragm method are being phased out one after another, and membrane electrode proton exchange membrane electrolysis technology is gradually becoming the absolute mainstream. Compared to conventional electrolyzers, membrane electrode electrolyzers save over 100 kWh of electricity, reaching an internationally leading level; their energy-saving effect is very significant. 　　In June 2010, a milestone event occurred in the chlor-alkali industry: Dongyue Group’s domestically produced perfluorinated ion exchange membranes were successfully used in a chlorine-alkali plant with a production capacity of 10,000 tons. This marked a significant breakthrough in China’s own core technologies and manufacturing capabilities related to ion exchange membranes for chlor-alkali production, breaking the long-standing foreign monopoly. 　　Furthermore, over the course of 40 years, the industry has developed a set of fully automatic PVC production technologies with independent intellectual property rights, capable of handling 200,000 tons per year, thereby achieving full domestic production of both the processes and equipment used in large-scale PVC manufacturing. The industry has also developed a series of large-scale PVC polymerization reactors, with their capacity increasing from 30 m3 and 70 m3 to 135 m3 at present, and the production capacity of each reactor rising from 5,000 tons per year to 67,000 tons per year. Various advanced treatment technologies such as membrane-based nitrate removal techniques, treatment methods for polymerization centrifuge mother liquor wastewater, and desulfurization techniques using calcium carbide slag have been adopted, resulting in a significant reduction in the emissions of waste materials, chemical oxygen demand, sulfur dioxide, and other key pollutants across the industry. Coupled with the ongoing use of mercury prevention and control technologies such as low-mercury catalysts, efficient gas-phase mercury removal techniques, hydrochloric acid desorption methods, and treatment technologies for mercury-containing wastewater, the industry’s environmental protection and mercury pollution control capabilities have been further enhanced, making significant contributions to the implementation of international conventions and global environmental governance.