The coiled-tube water-cooled reactor synthesis tower has been successfully put into operation; the large-methanol technology shows promise for domestic production

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The coil-type water-cooled reactor-based synthesis tower has been successfully put into operation; the large-scale methanol production technology shows promise for localization. Author/Source: China Chemical Industry News Date: July 5, 2016 Clicks: 56 On June 29, reporters from China Chemical Industry News learned from Hangzhou Linda Chemical Technology Engineering Co., Ltd. that the DN3600 methanol synthesis tower, designed and manufactured using their coil-type water-cooled reactor technology, was successfully deployed in Henan Shunda Chemical’s 300,000-ton/year methanol production facility, and as of the end of June, the tower was operating stably. The process package for the country’s largest 800,000 tons/year methanol plant has also been developed, which holds promise for the localization of advanced methanol production technologies. Feng Zainan, deputy general manager of Hangzhou Linda Chemical Technology Engineering Co., Ltd., explained that the synthesis tower of Henan Shunda Chemical’s 300,000 tons per year methanol production facility utilizes Linda Company’s coil-type water-cooled reactor technology; after being put into operation, it features a small temperature difference across the catalyst bed and a low circulation ratio. Actual operation data show that the current operating load of the unit is 65%–70%; when a single 50 m3/min circulator is used, the circulation ratio is only 1.9–2.08. Excluding the temperature-raising section at the upper part of the bed, the axial temperature difference is approximately 12°C, while the lateral temperature difference is less than 3°C. Achieving such a level of temperature control in a synthesis tower with a diameter of 3600 mm is relatively rare among the existing coal-to-methanol plants in China. Feng Zainan said that the methanol reactors currently in industrial use in China are mainly water-cooled types, which require a high level of structural reliability from the equipment. Tube-type water cooling towers suffer from high manufacturing difficulties due to the large number of tubes and numerous welds inside the tube sheet; they are prone to leakage issues and are difficult to maintain ； Reactors with catalysts filled outside the tubes are constrained by their structure; their specific surface area is generally less than 20 m2/m3. Overheating of the catalyst bed and excessive circulation rates are common problems, and there is also an issue of too many internal weld points, which makes it impossible to eliminate the risk of leaks ； Plate-type water cooling towers, due to their poor pressure resistance, fail to fully dissipate the stresses within their internal components, which leads to frequent leaks in the reactor during operation. To address the shortcomings of existing methanol reactors, LinDa Company conducted theoretical research and calculations on advanced coil-type heat exchanger structures and processes. It was found that, under the condition of co-current/counter-current flow of water and gas within the tubes, the heat transfer coefficient is nearly twice that of traditional reactors with water flowing inside straight tubes. In 2012, the company successfully developed a new generation of water-cooled coil-type reactors. This reactor not only overcomes the shortcomings of existing technologies, such as low heat transfer efficiency and difficulty in eliminating thermal stress on its own, but also addresses issues like difficult maintenance and leakage problems associated with conventional reactors. It ensures the safety of the equipment fundamentally, while also facilitating maintenance and simplifying production operations. Currently, Linda coiled-tube reactors have been successfully applied in fields such as methanol production, isothermal shift reaction, sulfur recovery, and ethanol synthesis. The reactors that are in operation have a maximum inner diameter of 4 meters, achieving the design objectives of good temperature control and high equipment reliability. In 2015, Linda Company won the bid for the project to produce 800,000 tons of methanol per year in Xinjiang Zhongheng. It has completed the preparation of the process package, and at the end of 2015 it signed an agreement with Sinopec Ningbo Engineering Company for the joint development of a process package for producing 1.8 million tons of methanol per year.