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This company relies on technological innovation to enhance its advantages in the caprolactam industry! Author/Source: Coal Chemical Industry Information Network Date: 2022-11-18 Clicks: 20 Recently, the application of new hydrogenation technology in the second-phase caprolactam production process at the Cangzhou plant of China Xuyang Group was successful. Unsaturated impurities often form during the caprolactam rearrangement reaction; if these impurities are not removed, they will affect the PM value of the resulting caprolactam. Hydrogenation converts unsaturated impurities into saturated ones, widening the boiling point difference between caprolactam and the impurities, thereby facilitating their removal during the evaporation distillation process. Currently, slurry bed technology is widely used for caprolactam hydrogenation in China. In simple terms, in a slurry bed reactor, the aqueous solution of caprolactam containing impurities is brought into contact with hydrogen through the continuous circulation of a catalyst; the unsaturated substances in this solution are hydrogenated to form saturated substances. Afterwards, a centrifugal separator is used to separate the catalyst from the reaction mixture after hydrogenation, so that it can be reused. This method requires the regular addition of catalysts, poses a high risk level, and involves significant labor costs for loading and unloading the catalysts; therefore, China Xuyang Group has adopted the country’s first fixed-bed hydrogenation technology for caprolactam production. The bubble column technology independently developed by Xuyang Group involves introducing hydrogen beneath the liquid phase, where it passes through the catalyst in a bubbling form to carry out the hydrogenation reaction. The caprolactam project in the second phase of Xuyang Cangzhou Park has further optimized its process flow: the hydrogenation and dissolution reactor has been removed, replaced by an efficient hydrogen mixer, thereby reducing investment costs ； At the same time, the fixed-bed process flow was innovated by installing parallel and series pipelines between the hydrogenation reactors, thereby enhancing the operational flexibility of the plant. Through the testing conducted during this feeding operation, this technical modification improved the hydrogenation efficiency; the PAN value of the produced hexanol-water mixture remained stable and controllable. Moreover, the preparation method of the hydrogenation catalyst required for this process is simple, the catalyst is easy to operate during use, it offers high safety, results in low production costs, and reduces the space occupied by the equipment. As a result, it helps to reduce catalyst consumption in the facility and improve the quality of the hexanol-water mixture. The stable and high-quality product quality has enhanced the image of our company’s caprolactam products, enabling us to secure a favorable market position. At 11:38 on September 25, 2022, the expansion project of Xuyang Group’s Cangzhou plant, designed to produce 300,000 tons of caprolactam per year, successfully produced high-quality caprolactam, achieving full operational capability and a successful commissioning in just one attempt. The main product of Xuyang Group’s Cangzhou plant is caprolactam, one of whose key raw materials is **. In China, the **production processes in use include oxidation, hydration, and phenol processes. The Cangzhou plant of Ruyi Group is equipped with two production units: the first unit uses the traditional oxidation method and has an annual production capacity of 135,000 tons, while the second unit employs the hydration method and has an annual production capacity of 270,000 tons. The second-phase hydration **unit is one of the key facilities in Xuyang Group’s Cangzhou plant’s expansion project, which aims to increase production capacity of caprolactam to 300,000 tons per year. It not only meets the raw material needs of the caprolactam production line in this expansion project but also satisfies 50% of the cyclohexane requirements of the first-phase oxidation **unit. This reduces the amount of raw materials that need to be purchased from outside, thereby helping to lower production costs and enabling synergistic benefits between the two phases. The hydroformylation unit in the second phase of Xuyang Group’s Cangzhou plant uses benzene and hydrogen as raw materials; it produces cyclohexene through partial hydrogenation of benzene, with cyclohexane as a by-product ； Cyclohexene hydration to produce cyclohexanol ； Cyclohexanol is dehydrogenated to produce **, which is then sent to the caprolactam plant after purification; hydrogen is generated as a by-product, and this hydrogen is used in the hydrogen peroxide plant after being purified. The hydration process it employs offers significant overall advantages over traditional oxidation processes: first, it reduces raw material consumption. The by-product of the hydration process is cyclohexane, which serves as the raw material for the first-stage oxidation process; this results in a conversion rate of nearly 100% for cyclohexane and 100% for carbon, while hydrogen consumption is reduced by one-third. The second is to reduce emissions. Gases and liquids are reduced by over 90% prior to separation, and a portion of the remaining waste is used as a clean fuel, thereby achieving both a significant improvement in green production levels and a substantial reduction in treatment costs. Third, it is safer. Both partial hydrogenation and hydration reactions are mild reactions that take place in an aqueous phase; they are safer, avoid corrosion or clogging by by-products, and offer greater operational stability. Fourth, the products have a high purity and excellent quality; there are virtually no by-products of acids and esters resulting from traditional manufacturing processes, which significantly reduces the requirements for wastewater treatment systems in subsequent processing steps. Throughout the entire process of design, construction, and commissioning of this second-phase hydration **facility, the highest standards of excellence were upheld in every aspect. In particular, extensive optimization efforts were carried out during the design phase and the early stages of construction, with a commitment to achieving the best possible results. For example, the country’s first hydrogenation reactor and hydration reactor of such large single-line capacity are used here, and an energy-saving solution for the dehydrogenation reaction products was implemented for the first time in collaboration with a design institute ； Building on the experience from Phase 1, light tower heat recovery, the second light tower, and dry vacuum pumps are directly included in the design scope ； Precise adjustments and continuous optimization to ensure the highest level of operability and safety, while minimizing energy consumption, resource use, and costs ； Wait.