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Record of the Renovation of the Mixed-bed System in Future Energy Company’s Desalination Unit / Author/Source: Yankuang Future Energy / Date: 2022-02-24 / Views: 13. As an **important strategic energy enterprise, Future Energy Company has, over the ten years it has been operating in Yulin, pursued a green and low-carbon development approach. It has continued to increase its investment in wastewater treatment, achieving zero wastewater discharge within the factory; at the same time, some of the treated water is reused. In order to make full use of the wastewater that can be reused beyond meeting the requirements for the normal operation of the coal liquefaction plant and to further reduce the costs associated with production water, the company uses some of the treated wastewater as feed water for the desalination system to produce desalinated water. After the recycled water was integrated into the desalination unit, it was found after some time of operation that although the various technical parameters of the recycled water produced by the dual-membrane process in the wastewater treatment plant were within acceptable limits, it contained a large amount of ions that could not be filtered out by the reverse osmosis membranes. As more and more of these \"ions\" entered the fresh water mixed-bed system of the desalination unit, the original processing procedures of this system gradually gave rise to various problems over time, such as a decrease in the amount of desalinated water produced, frequent system regeneration, high consumption of chemical agents, and an increase in the amount of impurities in the wastewater. These issues had a serious impact on the environmentally friendly and cost-effective operation of the desalination unit, creating obstacles to the recycling of \"recycled water\". Creative thinking reverses production challenges – Lu Fei is the head of the Production Technology Department at Future Energy Company. The issue of low output of \"reused water\" produced by the desalination plant often plagued Lu Fei. Lu Fei made up his mind secretly: no matter how much time it took, he was determined to remove this \"stumbling block\" that was hindering the operation of the desalination system. Therefore, no matter how busy his work is on a regular basis, whenever he has free time, Lu Fei would carefully study the operating patterns of the desalinated water production system using the PIMS flowchart, and seriously consider solutions to increase the water production volume. As time passed day by day, Lu Fei’s understanding of the operation of the desalinated water system also grew deeper. By chance, Lu Fei suddenly discovered that, before the desalinated water unit’s new water mixed-bed stopped functioning, it was the silica parameter, which indicates the failure of the anion resin, that first exceeded its acceptable level. Although Lu Fei had read the operational parameters related to silica thousands of times before, at this moment they inadvertently opened a door that had long troubled him, and a bold hypothesis quietly arose in his mind. “Is the problem of low water production per cycle in the fresh water mixed-bed system caused by an imbalance between cations and anions exchanged during its operation? ” “Currently, in the treatment of recycled water from the fresh water mixed-bed system, a significantly larger number of anions need to be exchanged compared to cations. If the order in which the anion and cation resins in this system are exchanged is reversed, will the operating cycle of the fresh water mixed-bed system change? ” The ideas in his mind became increasingly clear. Drawing on his many years of work experience, Lu Fei thought about it over and over again, and a bold solution gradually emerged: \"If a pre-treatment anion exchange column is added between the reverse osmosis unit and the fresh water mixed-bed system, it will be possible to absorb some of the anions present in the water before it enters that system, thereby balancing the amounts of cations and anions in the water.\" ” With this idea in mind, Lu Fei drafted a new technical renovation plan for the mixed-bed water treatment system overnight. He received support and encouragement from the company’s and department’s leaders, and inspired by this, he promptly contacted the water treatment workshop to coordinate the preparations for the renovation once the plan was approved. In the days that followed, Lu Fei spent his time at the desalination plant, constantly working to refine the details of the technical improvements. After more than ten days of intensive construction, one of the 8 new water mixed-bed units in the desalinated water plant was successfully transformed into a temporary anion exchange bed, without altering the equipment’s structure or the proportion of resin filled inside it. After the “new” unit was integrated into the desalinated water system, after one cycle of actual operation, Lu Fei was surprised to find that the mixed-bed unit, which previously produced 2,000–3,000 tons of fresh water per cycle, was able to produce as much as 9,000 tons in the same cycle after the addition of a temporary anion exchange bed. Meanwhile, the water production time of the new mixed-bed system was significantly extended; during the system regeneration process, the frequency of regeneration as well as the amount of chemical agents required were markedly reduced, and wastewater and concentrated water discharge were further decreased, demonstrating significant effectiveness of the experiment. After the preliminary tests were verified, Lu Fei became even more motivated to work. Over the following two weeks, he led the experimental team to continuously adjust and optimize the equipment, and successfully transformed the \"temporary anion bed\" into a \"pre-front anion bed\". To save on renovation and operation costs, Lu Fei used one \"anion bed\" as a pre-anion bed for two new mixed-bed reactors, operating them in a \"one-to-two\" configuration, which significantly reduced the renovation costs. Thanks to the relentless efforts of the experimental team, the cycle water production capacity of the new mixed-bed system after the \"one-to-two\" modification increased steadily, rising gradually from 9,000 tons per operating cycle to 13,000 tons – an increase of nearly 5 times compared to the 2,000–3,000 tons produced before the modification. Through cost analysis, each operating cycle of the experimental setup enables cost savings of around 22,400 yuan in terms of reduced chemical consumption, handling of wastewater, concentrated liquids, and impurities, as well as increased output of treated water. Over the course of a year, this results in cost savings of more than 2.2 million yuan. Once the entire new mixed-bed water treatment system is completed, it is expected to help the company save around 10 million yuan in costs per year. The success of the new mixed-bed renovation experiment not only resolved the long-standing bottleneck issues in the desalinated water system but also made it possible for the company to use its by-product recycled water to produce large quantities of desalinated water, thereby compensating for the shortcomings of traditional membrane-based processes for desalination. The successful experience has not only laid a solid foundation for the economic and stable operation of the desalinated water treatment units, but also provided practical examples and solutions for other units in the energy group’s chemical sector when dealing with similar issues. To recognize Lu Fei and his experimental team for their outstanding contributions to the renovation of the demineralization unit, the company awarded them 5,000 yuan. This reward is intended to encourage them to continue striving in their respective roles, to further uphold the spirit of innovation, perseverance, and problem-solving, and to make further contributions to the company’s high-quality development.