China’s largest controllable heat transfer conversion device has been successfully put into operation

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China’s largest controllable heat transfer shift unit put into operation successfully Author/Source: Yahu Coal Chemical Industry Date: March 26, 2018 Clicks: 20 On March 22, good news came from Shandong Hualu Hengsheng Chemical Co., Ltd.: the controllable heat transfer shift unit (commonly known as isothermal shift) designed to work in conjunction with 6.9MPa water-coal slurry gasification, as part of the company’s initiatives for upgrading its traditional industries and adopting cleaner production methods, was successfully put into operation on March 6 this year. This shift unit is capable of handling a wet basis gas flow rate of 950,000 Nm3/h. It is reported that this is the largest facility in China to operate controlled heat transfer conversion technology. The controlled heat transfer conversion furnace meets or exceeds the design values in all aspects: with a dry basis gas flow rate of 326,000 Nm3/h, an outlet CO level of ≤0.40%, a temperature difference across the same circular surface of ≤5°C, and a bed resistance of ≤0.021 MPa. It marks a major breakthrough in the scaling up of Type V controllable heat transfer conversion technology in our country. It is understood that this technology is the fifth-generation upgraded isothermal conversion technology developed by Nanjing Dunxian Chemical Technology Co., Ltd. In this technology, spherical chamber manifolds are used at the upper and lower ends of the reactor’s heat exchange tubes; the inlet and outlet water pipes are sealed to the shell’s gas-water interface through welding; and special heat exchange tubes are employed to eliminate thermal stress. As a result, the system is not only safe and robust but also allows for the inspection and maintenance of the catalyst frame without the need to remove the catalyst ； Successfully applied for the first time in large-scale coal chemical plants. Wang Qingxin, general manager of Nanjing Dunxian Company, said that since the first set of controllable heat-transfer conversion units came online at the end of 2012, the company has continued to increase its investment in technology and focus on innovation and research. Building on the original Generation I–IV conversion reactors, it developed the Type V controllable heat-transfer conversion reactor. A single-series conversion unit designed to work in conjunction with 6.9 MPa water-coal slurry gasification was successfully put into operation by Shandong Hualu Hengsheng Chemical Co., Ltd., marking a significant advancement in the application of controllable heat-transfer conversion technology in large-scale coal chemical industries. This experience has enabled Nanjing Dunxian Company to acquire valuable expertise in carrying out such projects, including the construction of 2.2 million tons per year of methanol production facilities in Ningxia Baofeng and 2 million tons per year of coal-to-oil production facilities in Inner Mongolia Yitai. Wang Qingxin told a reporter from China Chemical Industry News that this conversion unit features a completely new design. Construction began in late February 2016, and after nearly two years of work, it was successfully put into operation in early March this year. All its performance indicators meet or exceed those specified in the design. The Type V controllable heat transfer conversion technology effectively solves various problems associated with existing water-based heat transfer conversion systems, such as leakage in pressure-bearing components, difficulties in removing catalysts, dew point corrosion, and the challenge of scaling up single-unit systems. It offers a new conversion technology that requires low investment, ensures stable operation, helps reduce energy consumption, and facilitates the scaling up of modern coal chemical projects, including those for producing hydrogen, oil, natural gas, methanol, olefins, and ethylene glycol from coal, as well as for the energy-efficient renovation of existing conventional conversion systems. User feedback from Pan Desheng, Deputy General Manager of Shandong Hualu Hengsheng Chemical Co., Ltd.: This set of controllable heat transfer conversion devices has achieved the desired objectives, and compared with traditional adiabatic conversion technologies, it offers the following clear advantages: First, a single set of such conversion devices is capable of handling a gas flow rate of 950,000 Nm3/h on a wet basis; moreover, it allows for adjustments to the production capacity of ethylene glycol, methanol, and ammonia in response to fluctuations in their market prices, thereby helping enterprises maximize profits. The adjustment process is simple, safe, and rapid, which fully reflects the comprehensive, safe, stable, practical, simple, and versatile characteristics of the device’s process design and control system ； II. Compared with the traditional two-stage adiabatic shift process using 300,000 tons of synthetic ammonia, the adoption of controlled heat transfer shift technology reduced the CO content at the outlet of the shift system from 1.5% to 0.4%. Without increasing the volume of the feed gas, simply by improving the CO conversion rate, an additional 4,142 Nm3 of hydrogen was produced per hour; this resulted in an annual increase in synthetic ammonia production of 16,680 tons. The overall energy consumption per unit of synthetic ammonia produced decreased by about 1.5%, with annual energy savings amounting to 23,000 tons of standard coal. With just this alone, such enterprises can achieve a net profit of around 41.7 million yuan per year. Currently, there are nearly a hundred adiabatic conversion units for pressurized gasification of water-coal slurry in China, and the successful application of controlled heat transfer conversion technology will provide favorable conditions for these enterprises to save energy and improve efficiency ； III. The controllable heat transfer conversion technology primarily utilizes water housed in the heat transfer tube bundles embedded within the catalyst bed to remove the heat generated by the reactions. The temperature at the outlet of the catalyst bed remains constant. For water-coal slurry conversion units, this approach not only enables the production of superheated steam, results in greater recovery of high-quality thermal energy and less recovery of low-quality thermal energy, ensures stable subsequent heat recovery, and reduces engineering costs, but it also helps to extend the service life of the catalysts in each reactor ； IV. The resistance of the first radial adiabatic catalyst bed is ≤0.036 MPa, and that of the second variable heat-transfer radial bed is ≤0.021 MPa. Although the conversion system is equipped with 4 stages of steam evaporators, the total system resistance remains ≤0.37 MPa, which represents a reduction of 0.13–0.18 MPa compared to conventional two-stage axial adiabatic conversion systems. The operation of the radial catalyst beds lays a solid foundation for scaling up the system as a single-unit installation ； V. The terminal reactor in this conversion unit is a controllably heat-transferred conversion reactor; during the production of hydrogen for ethylene glycol and synthetic ammonia, a single pass of the gas through this reactor ensures that the CO level at the exit of the conversion system is ≤0.40%. This eliminates any impact of the conversion unit on the startup time, thereby reducing the costs associated with startup significantly ； VI. Type V controllable heat transfer transformation reactor: the upper and lower spherical chambers serve as heat exchange tube bank manifolds, effectively addressing the problem of thermal stress caused by isothermal conditions on the water side and non-isothermal conditions on the gas side of the manifolds. This setup facilitates the installation of an insulating layer around the catalyst bed, thereby achieving a balance between high temperatures on the outside and lower temperatures on the inside, effectively extending the catalyst’s service life and reducing operational energy consumption. It also facilitates the removal of the catalyst from the reactor. Expert opinion: Yang Chunsheng, senior advisor to the Shandong Fertilizer Industry Association, believes that innovation is the primary driving force for a company’s development. Only those who innovate can progress, become strong, and achieve success. Whenever a new technology emerges, it inevitably has various shortcomings, and it is up to those who innovate to continuously improve and refine it in order to keep this new technology at the forefront. Controllable heat transfer transformation (commonly known as isothermal transformation) is the only patent technology in the field of coal chemistry that was developed independently by Chinese researchers and is ahead of international standards. Nanjing Dunxian managed to develop reactors for types I to V of controlled heat transfer transformation within less than six years, and these reactors have been successfully applied in various systems such as exhaust gas utilization, coal-to-hydrogen production, fixed-bed coal gasification, pressurized coal gasification using pulverized coal, and pressurized coal slurry gasification. This demonstrates that the company places a strong emphasis on innovation and continuous improvement; it also shows that there are still many areas where improvements are needed in this technology. Transformation technology has a wide range of applications and utilizes diverse raw gas sources; it is hoped that patent technology companies will continue to strive for progress, be innovative, avoid arrogance and impatience, and further develop controlled heat transfer transformation (commonly known as isothermal transformation).