The ultra-large-scale ammonia synthesis energy-saving technology has passed the evaluation

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Industrial operation indicators are excellent, reaching international advanced levels. Source: China Chemical Industry News. On June 24, the JR ultra-large-scale ammonia synthesis energy-saving technology developed by Hebei Yangmei Zhengyuan Chemical Group Co., Ltd. passed the evaluation of scientific and technological achievements organized by the China Petroleum and Chemical Industry Federation in Shijiazhuang. The appraisal committee unanimously agreed that the technical and industrial performance indicators of this technology are excellent, stable, and reliable, reaching an internationally advanced level, and recommended accelerating its promotion and application. This technology has been in use for over 2 years at the largest single-ammonia synthesis plant in China, the \"60-80\" project of Cangzhou Zhengyuan Fertilizer Co., Ltd., which has an annual production capacity of 600,000 tons of ammonia and 800,000 tons of urea. The results of the 72-hour continuous operation test conducted on site in May by the China Nitrogen Fertilizer Industry Association showed that the degree of localization of the system’s equipment was 100%, and the daily production capacity of each ammonia synthesis tower was 2,186.3 tons, which represented 109% of the designed capacity ； System pressure: 15.14 MPa; system pressure drop: 0.708 MPa; pressure drop in the ammonia synthesis tower and high-pressure water system: 0.336 MPa; net ammonia yield: 17.56% ； The device operates stably and reliably, with all performance indicators meeting or exceeding the design values. It is reported that the main innovation of this technology lies in the development of a technical system for the storage, transportation, and loading of fully reduced catalysts, which reduces startup time and costs ； The internals of the ammonia synthesis tower adopt a suspension structure, which improves the reliability of the connection between the internals and the outer cylinder ； The inter-segment channels in the ammonia synthesis tower use self-weight sealing, which reduces the workload associated with installing the internal components and lowers the safety risks associated with filling them. This technology also uses heat transfer by water to recover the heat generated during the ammonia synthesis reaction, which allows for a reduction in the temperature of the gas exiting the tower, simplifies the ammonia synthesis process, reduces equipment costs, and significantly improves the efficiency of heat recovery. Liu Jincheng, the project’s overall supervisor and vice chairman of Yangmei Zhengyuan Chemical, told reporters that foreign large-scale ammonia synthesis plants of a single series have an early start in terms of technology development and high levels of maturity; the annual production capacity of the largest such plants exceeds 600,000 tons. At present, there are over 50 large-scale ammonia synthesis plants in operation in China. Among them, only one plant has a capacity of 600,000 tons per year – it is an imported plant – while the rest all have a capacity of 450,000 tons per year. Due to the immaturity of technology for large-scale ammonia synthesis plants in China, aside from the four large fertilizer projects in Shanghai, Sichuan, Jiangsu, and Ningxia that use domestically produced plants, all other plants were imported from abroad, at a cost of up to 15 million yuan. To break through technical monopolies, Yangmei Zhengyuan has independently developed a super-large JR ammonia synthesis tower with an annual production capacity of 600,000 tons, along with the associated process technologies, based on the existing patents for JR ammonia synthesis technology. This technology utilizes high-pressure water along with the recovery of waste heat from the ammonia synthesis reaction, along with two-stage ammonia cooling ； The ammonia synthesis tower features a three-stage adiabatic design, indirect heat exchange between stages, and a fully radial structure; it leads the industry in terms of indicators such as ammonia yield and reaction heat recovery rate. Currently, the heat utilization rate of reaction heat in ammonia synthesis units both domestically and internationally is 85%, while that of the JR3000-type ammonia synthesis unit reaches 95.3%. This technical device saves a total of 63.129 million yuan in terms of technology introduction costs, benefits from reduced-state catalysts, product profitability, and annual heat recovery benefits. International mainstream ammonia synthesis processes: Representative low-energy ammonia production processes around the world include the KBR process from the United States, the Topsoe process from Denmark, the Cassali process from Switzerland, and the Wood process from Germany. Among them, KBR’s ammonia synthesis towers are horizontal in design, which presents problems such as large space requirements, complex internal track structures, and difficulties in installation and maintenance ； The internal components of the ammonia synthesis tower in Casale are of a segmented design; their assembly is complex, sealing is difficult to ensure, and backmixing occurs, which hinders uniform airflow distribution within the tower as well as the smooth progress of the ammonia synthesis reaction. Currently, large-scale ammonia synthesis largely employs fully radial ammonia synthesis reactor internals with multi-stage adiabatic and indirect heat exchange; the design philosophy is primarily to increase the ammonia yield, as well as to ensure ease of installation and safety and reliability. The support for the internal components is located at the bottom of the ammonia synthesis tower, and the auxiliary lines for these components are connected using metal hoses or articulated bellows. Due to the limitations of the performance of metal hoses or articulated bellows, the amount of expansion of the inner component and the outer tube should not be excessive; in other words, the height of the inner component is limited. The full-radial ammonia synthesis tower is suitable for larger length-to-diameter ratios, which reduces the design and manufacturing complexity of the outer cylinder of the ammonia synthesis tower and lowers investment costs.