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Guidelines for Energy Conservation and Carbon Reduction Renovation and Upgrading in the Ammonia Synthesis Industry Author/Source: Date: 2022-02-15 Clicks: 50 I. Basic Information Ammonia has a wide range of applications; in addition to being used in the production of nitrogen fertilizers and compound fertilizers, it also serves as an important raw material for the inorganic and organic chemical industries. The synthetic ammonia process routes vary depending on the raw materials used, and mainly include processes such as raw gas preparation, raw gas purification, CO conversion, ammonia synthesis, and off-gas recovery. Energy consumption mainly consists of raw gas consumption, fuel gas consumption, coal consumption, steam consumption, and electricity consumption. There is a significant variation in the scale of the ammonia synthesis industry, with substantial differences in energy efficiency among different companies. Energy utilization is primarily plagued by issues such as low energy conversion efficiency and insufficient utilization of waste heat, offering significant potential for energy-saving and carbon-reduction upgrades. According to the \"Benchmark and Base Levels of Energy Efficiency in Key Areas of High-Energy-Consuming Industries (2021 Edition)\\", the benchmark level for energy efficiency in ammonia synthesis using high-quality anthracite coal as raw material is 1,100 kilograms of standard coal per ton, while the base level is 1,350 kilograms of standard coal per ton. For ammonia synthesis using low-quality anthracite coal or briquetted coal as raw material, the benchmark level is 1,200 kilograms of standard coal per ton, and the base level is 1,520 kilograms of standard coal per ton. In the case of ammonia synthesis using pulverized coal as raw material, the benchmark level is 1,350 kilograms of standard coal per ton, and the base level is 1,550 kilograms of standard coal per ton. For ammonia synthesis using natural gas as raw material, the benchmark level is 1,000 kilograms of standard coal per ton, and the base level is 1,200 kilograms of standard coal per ton. By the end of 2020, in China’s ammonia synthesis industry, approximately 7% of the production capacity had energy efficiency levels above the benchmark, while about 19% had energy efficiency levels below that benchmark. II. Work Directions (1) Strengthen the development and application of cutting-edge leading technologies, and foster benchmark enterprises. Conduct research and demonstration on green and low-carbon energy-based ammonia synthesis technology. Demonstrate dry pulverized coal gasification technology at 6.5 MPa and above to improve the gasification efficiency of the units; demonstrate, optimize, and timely promote the use of waste heat boilers or semi-waste heat boilers to recover waste heat from high-temperature syngas for steam generation, thereby replacing the fully quenching process used for syngas cooling and enhancing the thermal efficiency of coal gasification units. (II) Accelerate the widespread adoption of mature process equipment, and promote transformation and upgrading in an orderly manner. 1. Green technology processes. Optimize the structure of raw materials for ammonia synthesis and increase the proportion of green hydrogen as a raw material. Select large-scale air separation technologies and advanced processes, coupled with advanced control systems, to reduce power consumption. Increase research on technologies for producing ammonia from renewable resources in order to reduce carbon emissions in the ammonia synthesis process. 2. Major energy-saving equipment. Improve mass and heat transfer as well as energy conversion efficiency; enhance carbon monoxide shift reaction; replace adiabatic shift reactors with isothermal shift reactors. Apply counter-radiation and heat-absorbing coatings to improve the thermal efficiency of a section of the furnace. Large and efficient compressors such as air separation compressors, boosters, and syngas compressors are used, driven directly by steam turbines; electric drive is increasingly adopted to improve compression efficiency and avoid energy conversion losses. 3. Energy system optimization. Optimize the design of the gasifier and add a steam generation system using waste heat from high-temperature gas. Optimize the process design for urea production using carbon dioxide stripping, by adding a medium-pressure system. 4. Utilization of waste heat and pressure. While meeting the requirements of the process equipment, depending on the grade of waste heat generated in the process, this energy is used either to produce supplementary steam, to heat boiler feedwater or to preheat desalinated water and make-up water, or for power generation via an organic Rankine cycle, thereby ensuring that energy supply and demand as well as their respective grades are matched. 5. Renovation of public auxiliary facilities. Select various new types of efficient heat exchangers with low pressure drop based on the applicable scenario, in order to improve heat exchange efficiency. High-efficiency pumps and energy-saving motors are used to improve equipment efficiency. Use high-performance insulation and cold-insulation materials to enhance the insulation of equipment and pipelines. (III) Impose strict policy constraints to phase out outdated and inefficient production capacity. Strictly enforce relevant laws and regulations on energy conservation, environmental protection, quality, and safety technologies, as well as policies such as the \"Guidance Catalog for Industrial Structure Adjustment,\" in order to accelerate the phasing out of the cooling process in which high-temperature gas washing water comes into direct contact with air in open cooling towers, thereby significantly reducing the emission of air pollutants containing phenol, cyanide, and ammonia. III. Work Objectives By 2025, the proportion of production capacity in the synthetic ammonia industry that meets or exceeds the energy efficiency benchmark level is to reach 15%; production capacity below the energy efficiency baseline level is to be virtually eliminated. The industry is expected to achieve significant improvements in energy conservation and carbon reduction, with its capacity for green and low-carbon development being greatly enhanced.