The development of synthetic ammonia

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On the arduous path to synthesizing ammonia, it not only brought disgrace upon two outstanding chemists, Le Chatelier and Nernst, but also caused Haber, who made significant contributions to human societal development and was awarded the Nobel Prize in Chemistry for that, to degenerate into a shameful figure who aided the oppressors and turned against the people. Later, people referred to synthetic ammonia as the “Watergate incident” in the history of chemical development. In 1900, the French chemist Le Chatelier, based on his studies of equilibrium shifts and through theoretical calculations, concluded that N2 and H2 could combine directly to form ammonia under high pressure. He then attempted to verify this hypothesis experimentally, but an explosion occurred during the experiment. He did not investigate the cause of the accident; instead, he considered the experiment to be dangerous and abandoned the research work, resulting in the failure of his ammonia synthesis experiment. It was only later that the reason for the experiment’s failure was identified: the mixture of gases he used contained O2, and during the experiment, an explosive reaction occurred between H2 and O2. Later, the German chemist Nernst concluded through theoretical calculations that the synthesis of ammonia was not possible. As a result, research on the synthetic production of ammonia met with misfortune once again. It was only later that it was discovered he had used an incorrect thermodynamic value in his calculations, resulting in wrong conclusions. Faced with repeated setbacks in the research on ammonia synthesis, Haber persevered and conducted comprehensive and systematic studies and experiments on it. Finally, in July 1908, he managed to synthesize ammonia in the laboratory using N2 and H2 at 600°C and 200 atmospheres of pressure; although the yield was only 2%, it represented a significant breakthrough. Once Haber’s process was demonstrated, it immediately caught the attention of Germany’s military and political leaders, who had long harbored ambitions to conquer Europe and dominate the world through war. In order to make use of Haber, the German emperor even went to the trouble of inviting him to take up the position of director at Germany’s Wilhelm Institute. And the demon happened to cater to Haber’s greedy desire to become a millionaire. In just two years, from 1911 to 1913, Haber not only increased the yield of synthetic ammonia but also produced 1,000 tons of liquid ammonia, which was used to manufacture 3,500 tons of the powerful **T*T**. By the time of World War I in 1913, Haber had built numerous small ammonia synthesis plants for Germany, producing millions of tons of ammonia for the aggressors, which led to and spread this world war that brought disaster to the entire globe. This is the answer to the mystery of why Germany was able to hold out for so long during World War I. When the truth came to light, Haber faced fierce criticism from scientists around the world; his receipt of the Nobel Prize in Chemistry in 1918 only intensified the anger of people across the globe. The success of the artificial ammonia synthesis experiment was encouraging, and its great significance for industry, agricultural production, and international science and technology is self-evident; yet for those three outstanding scientists, it was a dark \"Watergate scandal\". Before 1949, there were only two ammonia synthesis plants across the country, located in Nanjing and Dalian, and a small ammonia synthesis workshop in Shanghai that used hydrogen produced by water electrolysis as raw material; the combined annual production capacity was 46 kt of ammonia. After the founding of the People’s Republic of China, the production of synthetic ammonia grew rapidly. To meet the urgent needs of agricultural development, in addition to restoring and expanding existing plants, four ammonia plants were built in Jilin, Lanzhou, Taiyuan, and Sichuan during the 1950s. Building on the successful development of high-pressure reciprocating nitrogen-hydrogen compressors and high-pressure ammonia synthesis towers, more than 20 medium-sized ammonia plants were constructed in Yunnan, Shanghai, Quzhou, Guangzhou and other places in the 1960s. Furthermore, drawing on international experience, a generic design for an ammonia plant with an annual production capacity of 50 kt was developed using the “three-catalyst” process (zinc oxide desulfurization, low-temperature shift, and methanation), which was then applied at the Shijiazhuang Fertilizer Plant. At the same time, a new process for the combined production of ammonia and ammonium bicarbonate was developed, and a large number of small ammonia plants with an annual production capacity of 5–20 kt of ammonia were built; a considerable portion of these plants used bituminous coal instead of coke in their production. From the 1970s through the 1980s, large ammonia plants with advanced technology were built to produce 300 kt of ammonia per year, using natural gas, naphtha, heavy oil, and coal as raw materials; these plants were located in Sichuan, Jiangsu, Zhejiang, Shanxi, and other regions. The production in 1983 and 1984 was 16,770 kt and 18,373 kt respectively (excluding Taiwan Province), ranking second in the world after the Soviet Union. Currently, there are 15 large-scale plants using various fuels as raw materials and operating through different processes, 57 medium-sized plants, and over 1,200 small-scale plants, with an annual production capacity of nearly 20 Mt of ammonia. Currently, China is the largest producer and consumer of fertilizers in the world, with an annual production capacity for synthetic ammonia reaching 42.22 million tons. However, synthetic ammonia has always been a major energy consumer in the chemical industry. From June 7th to 8th, a technical exchange meeting on national synthetic ammonia energy-saving renovation projects was held in Beijing, where specific goals for synthetic ammonia energy-saving projects during the 11th Five-Year Plan period were established in terms of reducing consumption and protecting the environment. In line with the plans outlined in the \"Implementation Plan for Energy Optimization and Saving Projects in Ammonia Synthesis during the 11th Five-Year Plan Period,\" the goal of this key energy-saving project is to enable large-scale ammonia synthesis plants to use advanced energy-saving processes, new types of catalysts, and efficient energy-saving equipment in order to improve conversion efficiency and enhance the recovery and utilization of waste heat ； The waste heat recovery technology for the flue gas of the first-stage furnace is adopted in ammonia synthesis using natural gas as raw material, and the steam system is upgraded ； The use of petroleum as a raw material for synthetic ammonia is accelerating the transition to using clean coal or natural gas as alternatives to crude oil ； Small and medium-sized ammonia synthesis plants use energy-saving equipment and pressure swing adsorption recovery technologies to reduce energy consumption. Coal gasification uses water-coal slurry or advanced pulverized coal gasification technology to replace the traditional fixed-bed gasification technique. By 2010, the energy-saving target for the synthetic ammonia industry was to reduce energy consumption per ton from the current level of 1,700 kilograms of standard coal per ton to 1,570 kilograms of standard coal per ton ； Energy utilization efficiency has increased from 42.0% to 45.5% ； It is possible to achieve energy savings of 5.7 million to 5.85 million tons of standard coal, thereby reducing carbon dioxide emissions by 13.77 million to 14.13 million tons. It is understood that over the past decade or so, China’s ammonia synthesis plants have undergone numerous repeated modifications to their feedstock pathways as well as energy-saving upgrades, including changes from oil to coal, from coal to oil, from oil to gas, and from anthracite to pulverized coal. Dozens of major renovations have been carried out in areas such as the hydrocarbon steam conversion section, the shift reaction section, the decarburization section, and the control systems. Among them, technical upgrades such as gas generation furnaces, furnace condition monitoring and system optimization, and desulfurization systems have always been a priority. However, due to various factors such as the raw material supply chain for the equipment, resource availability, transportation, as well as the maturity of funds and technology, the effectiveness of energy-saving technological upgrades for ammonia synthesis has never met the expected goals. By the end of 2004, the average energy consumption per unit of synthetic ammonia was 1,700 kilograms of standard coal per ton; the average level for ammonia production was 600–700 kilograms of standard coal lower than the international advanced level. It is understood that the specific implementation of the energy-saving renovation project for synthetic ammonia is carried out by the China Chemical Industry Energy-Saving Technology Association.