Under the “dual carbon” target, the demand for hydrogen in China’s synthetic ammonia industry and its decarbonization path.
Abstract: Ammonia (NH3) is one of the important chemical products in modern society, with important applications in agriculture and industry. Currently, the production of raw material hydrogen in China’s synthetic ammonia process is mainly based on fossil energy. In order to achieve the “dual carbon” target and effectively alleviate the problem of high carbon emissions, green synthetic ammonia technologies such as electrolytic hydrogen production and clean ammonia utilization technologies have become important breakthroughs. This article studies the current status and future trends of China’s synthetic ammonia, and based on the Long-term Energy Alternatives Planning (LEAP) model and economic drivers, considers different raw materials for ammonia synthesis, and simulates the hydrogen demand and carbon emissions trend of China’s synthetic ammonia industry from 2020 to 2060, with hydrogen prices and policies as the main driving factors. The results show that by 2060, China’s synthetic ammonia demand will reach 120 million tons, and the demand for hydrogen will reach 21.28 million tons. The new demand mainly comes from new fields such as ship ammonia fuel and ammonia power generation, exceeding 50% of the hydrogen demand for synthetic ammonia. China’s synthetic ammonia industry has great potential to transition from fossil energy to renewable energy. With the decrease in the cost of renewable hydrogen production, the proportion of renewable hydrogen production for ammonia synthesis will increase substantially, exceeding 97%. In terms of carbon emissions, China’s synthetic ammonia industry will peak in 2030, with a peak of 220 million tons, and carbon emissions from the synthetic ammonia industry will reach 9.2 million tons by 2060. To achieve the carbon neutrality target, China should prioritize the demonstration projects of electrolytic hydrogen production for ammonia synthesis in regions with abundant renewable energy, increase the research and application of key technologies such as electrolytic hydrogen production and mild conditions for ammonia synthesis, and achieve large-scale application of low-carbon ammonia synthesis technology as soon as possible. In terms of ammonia application, more research should be done on ammonia-fueled engines and mixed ammonia power generation.
Keywords: LEAP model; synthetic ammonia; hydrogen energy; carbon emissions; green ammonia.
Source: Energy Storage Science and Technology Authors: Yalin Xiong, Wei Liu, et al. In September 2021, China proposed a vision of achieving carbon peak in 2030 and carbon neutrality in 2060. To achieve the dual carbon target, clean energy such as hydrogen and green ammonia have become important paths for deep decarbonization. Ammonia (NH3) is one of the most important chemical products in modern society and is also the first chemical product to achieve large-scale industrial production through heterogeneous catalysis. Ammonia is closely related to the development of human society. In the past hundred years, the application of ammonia in the field of agriculture has been the main source of China’s synthetic ammonia demand. Thanks to the large-scale application of nitrogen fertilizer produced from ammonia as a raw material, global food production has grown rapidly. A small part of ammonia is used as a raw material for synthetic fibers, explosives, and plastics in the industrial sector, but the synthesis of ammonia has problems such as high energy consumption and high emissions. In 2020, China’s synthetic ammonia energy consumption was 71.983 million tons of standard coal, accounting for about 1.4% of the total national energy consumption. The direct carbon dioxide emissions were 219 million tons, accounting for 19.9% of the total chemical industry emissions and 2.2% of China’s total carbon emissions. The high emissions are mainly due to the production of raw material hydrogen in China’s synthetic ammonia process, which is mainly based on coal. Under the dual carbon target, front-end clean substitution represented by electrolytic hydrogen production for ammonia synthesis.
1 Development Status of my country’s Synthetic Ammonia Industry
1.1 CURRENT SITUATION OF MY COUNTRY’S SYNTHETIC AMMONIA INDUSTRY
my country is the largest producer of ammonia, accounting for 30% of global production. According to the statistics of the National Bureau of Statistics, my country’s synthetic ammonia production from 2005 to 2020 is shown in Figure 2. Since 2005, my country’s synthetic ammonia production has been increasing year by year, reaching a peak of 57.91 million tons in 2015. Since the 13th Five-Year Plan, the Ministry of Industry and Information Technology has required key industries to eliminate backward and excess production capacity. Among them, the synthetic ammonia industry must not be less than 10 million tons. In the past five years, my country’s synthetic ammonia production has been reduced year by year due to environmental protection restrictions and the elimination of backward production capacity. , reaching the lowest level of 45.87 million tons in 2018. From the perspective of downstream consumption structure, there is a trend of “weight loss and increase in chemical consumption”. The ammonia used for fertilizer production has dropped from 90% in 2010 to 70% of the current total. As my country’s population growth slows down, gradually stabilizes and declines slowly, the current use of chemical fertilizers per unit of arable land in China is already at a high level, and domestic chemical fertilizer consumption will gradually show a gradual downward trend. The remaining 30% of ammonia is used in a series of industrial production. Ammonia is an important chemical product and raw material. It is an important auxiliary agent for commonly used inorganic solvents, refrigerants, flue gas and tail gas denitrification. The main raw material of chemical products such as acrylonitrile, rubber and chemical fiber. However, synthetic ammonia will play an important role in some emerging fields. Ammonia can replace most of the current application scenarios of fossil fuels, especially in ship fuel and coal-fired power plants mixed with ammonia for power generation, which will become a new driving force for the increased demand for synthetic ammonia. From the perspective of production capacity distribution, my country’s synthetic ammonia production capacity areas are mainly distributed in Shandong, Shanxi, Henan, Inner Mongolia, Xinjiang, Jiangsu and other areas with better resource conditions. The production capacity of synthetic ammonia in these areas accounts for about 2/3 of the total. In the future, the layout of nitrogen fertilizer and other industries will further concentrate on raw material resources to achieve nearby transformation and reduce pollution and losses. With the layout of the green hydrogen industry, there will also be a trend of shifting to the west and other regions rich in renewable energy. From the perspective of hydrogen sources for synthetic ammonia, according to statistics from the China Hydrogen Energy Alliance, the demand for hydrogen from synthetic ammonia is the largest hydrogen terminal consumption area, as shown in Figure 3. In 2019, the output of synthetic ammonia was 57.6 million tons, and the consumption of hydrogen as an intermediate raw material for the production of synthetic ammonia was 10.8 million tons, accounting for 32.3% of the total hydrogen demand. From the perspective of hydrogen source structure, 81% of the hydrogen comes from the coal gasification process, 16.6% of the hydrogen is produced from natural gas reforming, and the remaining 2.4% of the hydrogen comes from coke by-product hydrogen and semi-coke by-product hydrogen, as shown in Figure 4 .
1.2 CURRENT STATUS OF TECHNOLOGY
1.2.1 Ammonia Synthesis Technology At present, the Haber-Bosch method is still the only industrial-scale ammonia synthesis technology in the world. This method mainly includes three main steps: gas generation, purification, and compression synthesis. The first is gas production, which uses natural gas and coal as raw materials to prepare crude raw material gas containing hydrogen, nitrogen, and carbon monoxide; the second is purification. The crude gas produced during the gas production process contains impurities such as carbon monoxide and carbon dioxide, which cannot corrode pipelines equipment, and can poison the catalyst, so the hydrogen-nitrogen raw material gas must be purified before being sent to the synthesis tower to remove various impurities and obtain pure ammonia-nitrogen mixed gas; the third is compression and synthesis, which is mainly the Haber-Bosch process, Compress pure hydrogen-nitrogen mixed raw material gas to high pressure, and synthesize ammonia under catalyst and high temperature conditions. Renewable electricity synthesis ammonia technology replaces fossil energy (coal, natural gas) in traditional processes with hydrogen generated by clean energy electrolysis of water, and reacts with nitrogen obtained from the air separation system to generate ammonia. The traditional Haber-Bosch synthetic ammonia is limited by thermodynamics, and the conversion rate is only 10% to 15%. With the massive consumption of fossil fuels and the increasing environmental degradation in recent years, it is urgent to find an alternative route to the green and environmentally friendly ammonia synthesis process. The electrolysis of water to hydrogen synthesis ammonia process will be the trend of future development. The national key research and development plan of the Ministry of Science and Technology of my country is carried out in two aspects, one is the green replacement of hydrogen sources, and the other is the low-temperature and low-pressure synthesis process. The electrochemical synthesis of ammonia can be carried out at low temperature and normal pressure. The reaction process is clean and environmentally friendly. Compared with the Haber-Bosch process, the energy consumption is reduced by about 20%, and it is not limited by thermodynamics. In 2021, the “Hydrogen Energy Technology” project supported the “Electrolytic Hydrogen Production – Key Technology and Application of Ammonia Synthesis at Low Temperature and Low Pressure” and the “100,000-ton Renewable Energy Electrolyzed Water Hydrogen Production and Ammonia Demonstration Project”, and carried out electrolysis hydrogen production and ammonia synthesis under mild conditions. Technology and application, breaking through the new technology of near-atmospheric hydrogen and nitrogen synthesis ammonia, and exploring a new path for the complementary integration of renewable energy and low-temperature and low-pressure ammonia synthesis. 1.2. 2 Ammonia Utilization: Research on Marine Ammonia Fuel With the implementation of the International Maritime Organization (IMO) regulations on harmful emissions and the continuous guidance and promotion of national and local policies, the ship industry has ushered in an opportunity to control air pollutants and address climate change. Ships powered by low-carbon/zero-carbon fuels have entered a period of rapid development, and the market prospect of shipping carbon reduction technology is very broad. Due to the zero-carbon properties of ammonia, it will not produce carbon emissions when used as fuel for internal combustion engines. In addition, the volumetric energy density of ammonia is higher than that of hydrogen, which can improve the space utilization of the hull, thus making it economically feasible to store ammonia fuel on board. According to estimates by the Energy Transitions Council (ETC), ammonia is the “fuel of last resort” for ocean-going vessels in the long run, with the total amount of ammonia used as shipping fuel equivalent to more than half of conventional agricultural and industrial use. To meet the demands of the international shipping fleet, more than 650 million tons of ammonia are required, equivalent to 6,500 TWh of renewable energy generation. Therefore, using electrolysis to produce green ammonia at a reasonable cost is currently the main research direction. Although my country has completed the development and design of ammonia-fueled bulk carriers, the technology of ammonia-fueled engines is relatively backward, and research and development support can be increased in the future. The world’s leading marine powertrain suppliers such as Winterthur Engine Co., Ltd. (WinGD) and MAN Group (MAN) have begun to deploy ammonia-fueled low-speed engine research and development, which is expected to be put on the market in 2024, leading the energy and marine industry. Industrial transition to zero-carbon solutions. 1.2.3 Ammonia utilization: Research on coal-fired ammonia-mixed power generation. my country’s coal-fired power generation has a large installed capacity, short service life, large carbon emissions, and difficult transformation. It is imminent to resolve the structural risks of coal power. my country’s carbon dioxide emissions from coal-fired power generation account for about 34% of my country’s total carbon dioxide emissions. Reducing carbon dioxide emissions from coal-fired power generation is the key to my country’s successful realization of the goal of carbon neutrality. Even if a small amount of ammonia is mixed to replace coal, it can To reduce extremely considerable carbon emissions, many scientific research teams have carried out research on the co-combustion of ammonia and pulverized coal in boilers. However, at present, the combustion characteristics of ammonia under different operating conditions, such as ignition delay time, flame speed and structure, combustion limit, NO More than 500 million tons of ammonia, equivalent to 6500 TWh of renewable energy generation. Therefore, using electrolysis to produce green ammonia at a reasonable cost is currently the main research direction. Although my country has completed the development and design of ammonia-fueled bulk carriers, the technology of ammonia-fueled engines is relatively backward, and research and development support can be increased in the future. The world’s leading marine powertrain suppliers such as Winterthur Engine Co., Ltd. (WinGD) and MAN Group (MAN) have begun to deploy ammonia-fueled low-speed engine research and development, which is expected to be put on the market in 2024, leading the energy and marine industry Industrial transition to zero-carbon solutions. 1.2.3 Ammonia utilization: research on coal-fired ammonia-mixed power generation. my country’s coal-fired power generation has a large installed capacity, short service life, large carbon emissions, and difficult transformation. It is imminent to resolve the structural risks of coal power. my country’s carbon dioxide emissions from coal-fired power generation account for about 34% of my country’s total carbon dioxide emissions. Reducing carbon dioxide emissions from coal-fired power generation is the key to my country’s successful realization of carbon neutrality. To reduce extremely considerable carbon emissions, many scientific research teams have carried out research on the co-combustion of ammonia and pulverized coal in boilers. However, at present, the combustion characteristics of ammonia under different operating conditions, such as ignition delay time, flame speed and structure, combustion limit, NO More than 500 million tons of ammonia, equivalent to 6500 TWh of renewable energy generation. Therefore, using electrolysis to produce green ammonia at a reasonable cost is currently the main research direction. Although my country has completed the development and design of ammonia-fueled bulk carriers, the technology of ammonia-fueled engines is relatively backward, and research and development support can be increased in the future. The world’s leading marine powertrain suppliers such as Winterthur Engine Co., Ltd. (WinGD) and MAN Group (MAN) have begun to deploy ammonia-fueled low-speed engine research and development, which is expected to be put on the market in 2024, leading the energy and marine industry. Industrial transition to zero-carbon solutions. 1.2.3 Ammonia utilization: Research on coal-fired ammonia-mixed power generation. my country’s coal-fired power generation has a large installed capacity, short service life, large carbon emissions, and difficult transformation. It is imminent to resolve the structural risks of coal power. my country’s carbon dioxide emissions from coal-fired power generation account for about 34% of my country’s total carbon dioxide emissions. Reducing carbon dioxide emissions from coal-fired power generation is the key to my country’s successful realization of the goal of carbon neutrality. Even if a small amount of ammonia is mixed to replace coal, it can To reduce extremely considerable carbon emissions, many scientific research teams have carried out research on the co-combustion of ammonia and pulverized coal in boilers. However, at present, the combustion characteristics of ammonia under different operating conditions, such as ignition delay time, flame speed and structure, combustion limit, NOxKey parameters such as generation characteristics have not yet been perfected, and the reaction kinetic mechanism of ammonia combustion is still in the stage of continuous verification and improvement. The ammonia-doped power generation technology still faces challenges in the commercialization of coal-fired power plants. Global research on using ammonia as a low-carbon fuel for boilers is still in its infancy, and all of them focus on small-scale research in laboratories or pilot scales. The large-scale use of ammonia as a low-carbon fuel has not yet been verified on an industrial scale. feasibility. The National Energy Group has realized the industrial application of mixed ammonia combustion on a 40 MW coal-fired boiler with a blending ratio of 35%, developed a flexible and adjustable ammonia mixed low-nitrogen pulverized coal burner, and equipped with a multi-variable adjustable ammonia supply system , completed the overall research on ammonia-coal mixed combustion technology, provided basic data and technical solutions for the industrial application of higher-level coal-fired boiler ammonia-mixed combustion systems, and marked that my country’s coal-fired boiler mixed-ammonia technology has entered the world’s leading ranks .
1.3 SUPPLY AND TRADE OF AMMONIA
Ammonia is a global commodity with transparent pricing. The entire production, transportation, and trading market has existed for a long time and is mature. Its markets are all over the world, and global exports account for about 10% of the total output. Regions rich in natural gas such as Russia and Trinidad and Tobago are major exporting countries and regions, achieving economic growth through trade and export of ammonia and its derivatives. Compared with hydrogen, ammonia, as a mature chemical product, has a complete commercial supply chain system from factory preparation, storage, transportation and use. Vital infrastructure such as dedicated ports, pipelines and storage facilities for ammonia is critical to ammonia trade. Under the background of global carbon reduction, the international community has higher and higher low-carbon requirements for commodities, and green ammonia produced by renewable hydrogen has become the development requirement and trend of ammonia trade in the future. my country has a huge advantage in renewable electricity required for the production of clean ammonia fuel. While meeting domestic ammonia application needs, we will develop green ammonia in the future with the help of a mature domestic supply chain system and the surrounding markets with large demand for ammonia in Japan and South Korea. International trade has huge potential.
2 Principle of analysis model
This study uses the scenario analysis model, specifically the LEAP model (long-range energy alternatives planning system) tool based on the long-range energy alternatives planning system, which includes energy supply, energy processing and conversion, and terminal energy demand; this model can be used mainly in countries and Urban medium- and long-term energy and environmental planning, analyzing and predicting the medium- and long-term energy supply and demand of the whole society under different driving factors, and calculating the conventional air pollutants and greenhouse gas emissions in the process of energy circulation and consumption. The model divides terminal energy consumption into sectors such as industry and transportation. The operation of the model requires the input of a large amount of statistical data and predictive data. These data mainly come from China Statistical Yearbook, China Energy Statistical Yearbook data, major industry research institutions at home and abroad and related forecasts of leading countries. According to the different downstream application scenarios of ammonia, the LEAP model will analyze the ammonia demand of the traditional agricultural sector and industrial sector and the ammonia demand of the transportation sector and power generation sector in new fields based on economical efficiency and carbon emission reduction effects. The analysis idea is shown in Figure 8.
3 Synthetic ammonia and hydrogen demand forecast
3.1 ECONOMY
For the technical penetration rate of ammonia in the new application fields of the transportation sector and power generation sector represented by ship transportation fuel and combustion power generation, it is necessary to conduct a comprehensive analysis based on the economics and carbon emission reduction benefits of ammonia fuel utilization technology and traditional technology. Ship transportation fuel: Traditional fuel-powered ships use diesel engines for main power and auxiliary power, and the fuel is heavy oil. Ammonia fuel-powered ships use ammonia engines as the main power and hydrogen fuel cells as auxiliary power. According to the parameters of the main and auxiliary engines of traditional fuel-powered ships assumed in Table 1 and the Asia-Europe route settings, the fuel consumption of the main and auxiliary engines is calculated to be 240 t/d and 16 t/d, respectively. Since the ammonia powertrain has not been put into the market at present, the ammonia consumption of ammonia-powered ships is converted to 419 t/d by using the equivalent calorific value method, and the equivalent hydrogen consumption is 9 t/d. The economic analysis is shown in Figure 9. When the price of heavy oil is 4000 CNY/t, considering the carbon emission of traditional power ships, according to the carbon emission coefficient of heavy oil, when the carbon price is 500 CNY/t, renewable hydrogen When the price is 18 CNY/kg, the cost of synthetic ammonia is 3684 CNY/t. At this time, ammonia fuel-powered ships are cost-competitive. Combustion power generation: This article compares the economy of thermal power generation with the economy of 35% ammonia doping. In order to better demonstrate the economic comparison results, this paper mainly considers the economic impact of different fuels and carbon prices on power generation, and does not consider equipment modification and labor depreciation for the time being. The average power supply coal consumption of active coal-fired thermal power plants is calculated as 320 g standard coal/kWh, and the calorific ratio of coal-fired ammonia mixed with 35% is calculated. The comparison of economical calculations based on the combustion calorific value of ammonia and the emission coefficient of standard coal is shown in Figure 10. Considering the carbon benefits produced by the two power generation technologies, and calculating the carbon emissions in the respective power generation processes based on the carbon emission coefficients of standard coal, when the coal price is 1400 CNY/t and the carbon price is 500 CNY/t, the price of renewable hydrogen The cost of synthetic ammonia is about 16 CNY/kg, and the cost of synthetic ammonia is 3275 CNY/t. Only coal-fired ammonia-mixed power generation is economical. Renewable Hydrogen: The cost of renewable hydrogen determines the market penetration of green ammonia in transportation and power generation. As shown in Figure 11, at 2000 m3/h alkaline electrolyzed water hydrogen production project as an example, under the load rate of 95%, the current levelized cost of hydropower, onshore wind power, offshore wind power, and photovoltaics is 0.33 CNY/kWh, 0.41 CNY/kWh, and 0.63 CNY/kWh, respectively. CNY/kWh, 0.40 CNY/kWh, the corresponding levelized hydrogen costs are 22.89 CNY/kg hydrogen, 27.65 CNY/kg hydrogen, 40.05 CNY/kg hydrogen, 26.65 CNY/kg hydrogen. Among them, the cost of electricity per kilowatt-hour has the highest sensitivity to the cost of renewable hydrogen, accounting for about 70% to 90% of the total cost. The expansion of renewable energy installed capacity and continuous technological progress will drive down the cost of renewable energy power generation. After 2035, the newly installed power generation costs of photovoltaic and wind power are expected to drop to 0.2 CNY/kWh and 0.3 CNY/kWh respectively. By 2050, the cost of new photovoltaic and wind power generation will drop to about 0.13 CNY/kWh and 0.25 CNY/kWh, and wind power and solar power will become the cheapest and most abundant source of electricity. The cost of hydrogen production from renewable energy electrolysis water will be as low as 11.63 CNY/kg hydrogen, which is significantly lower than the cost of hydrogen production from fossil energy + carbon capture and storage (CCS) without considering the carbon tax.Figure 11 Levelized cost of renewable hydrogen Based on the above analysis, whether it is green ammonia synthesis, ship fuel, coal blending and other new fields, it is necessary to achieve economic efficiency when the price of hydrogen is low. On the one hand, it is necessary to promote the scale-up of renewable energy hydrogen production as soon as possible, build a low-carbon and clean hydrogen supply system, give full play to the role of hydrogen itself as an energy interconnection medium, and realize the green development of the entire industrial chain; on the other hand, the domestic carbon market trading mechanism and The price of carbon emission quotas is difficult to support the development of the green ammonia industry, and it is necessary to improve the system and mechanism in time.
3.2 FORECAST OF SYNTHETIC AMMONIA AND HYDROGEN DEMAND
The forecast of hydrogen energy demand in my country’s synthetic ammonia industry is considered from two aspects. One is the original synthetic ammonia market such as fertilizer and chemical industry, and the other is new application fields such as marine ammonia fuel and ammonia-mixed combustion. 3.2.1 The field of traditional synthetic ammonia At present, my country’s synthetic ammonia industry has entered a stage of slight growth. With the improvement of fertilizer efficiency and the substitution of organic fertilizers, the consumption of synthetic ammonia in agriculture will drop to 60% in the future. The consumption in the non-agricultural field is driven by industrial consumption such as environmental protection, new materials, and special chemicals, and the demand is increasing. However, the demand for traditional synthetic ammonia shows a steady and declining trend. In 2060, it will drop to 55 million tons, and the demand for hydrogen will be 9.72 million tons. 3.2. 2 Emerging synthetic ammonia field In the field of transportation, in terms of the penetration rate of ammonia fuel in marine energy, based on the assumption that my country is accelerating the technology research and development of ammonia fuel ships, implement medium-to-high-intensity energy transformation policies to improve the cleanliness rate of energy consumption of fuel ships. Gradually implement pilot projects in advantageous areas. Combining the results of the economic analysis in Figures 9 and 11, the penetration will gradually increase when the economy is achieved. With the rapid reduction of the cost of renewable energy per unit of electricity, especially photovoltaic power generation will take the lead in 2035 when the levelized cost of hydrogen is lower than 15 CNY/kg hydrogen, it is estimated that around 2035, the economy of ammonia-powered ships will be equal to that of traditional fuel-powered ships. The demand for hydrogen reached 1.17 million tons, and the demand for hydrogen was 210,000 tons; since then, the penetration rate has increased rapidly. In 2040 and 2050, the penetration rate of ammonia-powered ships in ship fuels will rise rapidly to 5% and 25%. The demand penetration rate exceeds 40%, the consumption of synthetic ammonia is nearly 65 million tons, and the demand for hydrogen is 11.5 million tons, as shown in Figure 12. In the field of power generation, according to the forecast of my country’s 2020-2060 power installed capacity by the Global Energy Internet Development and Cooperation Organization, my country’s coal power installed capacity will reach a peak of 1.1 billion kilowatts in 2025, and then the coal power installed capacity will decline year by year. By 2060, the coal power installed capacity will be completely withdrawn from my country power structure. In 2035, the economy of ammonia-doped power generation can compete with that of coal-fired power generation. The proportion of ammonia-doped power is based on the National Energy Group’s demonstration coal-fired boiler burning 35% mixed ammonia fuel. It is estimated that the demand for ammonia will reach 5.4 million tons, and the demand for hydrogen will reach 1 million tons. In 2050, as the penetration rate of ammonia-doped power generation in coal power applications gradually increases to 30%, the demand for ammonia will be 47 million tons and the demand for hydrogen will be 8.4 million tons. On the whole, the total demand for hydrogen in the synthetic ammonia industry has shown a trend of rising year by year and then fine-tuning and falling, from 10.8 million tons of hydrogen in 2019 to 25 million tons in 2050, and then due to the withdrawal of coal power, the demand for ammonia-doped power generation decreased. In 2060, it will be reduced to 21.28 million tons. According to the forecast results of the model, with the advancement of technology, the reduction of the cost of renewable hydrogen, and the maturity of the carbon market, the main increase will be in emerging fields such as ammonia-fueled shipping and ammonia-doped power generation. In 2060, the hydrogen required for emerging fields will reach 11.5 million tons, more than 50% of the total hydrogen demand in the ammonia industry. On the whole, the total demand for hydrogen in the synthetic ammonia industry has shown a trend of rising year by year and then fine-tuning and falling, from 10.8 million tons of hydrogen in 2019 to 25 million tons in 2050, and then due to the withdrawal of coal power, the demand for ammonia-doped power generation decreased. In 2060, it will be reduced to 21.28 million tons. According to the forecast results of the model, with the advancement of technology, the reduction of the cost of renewable hydrogen, and the maturity of the carbon market, the main increase will be in emerging fields such as ammonia-fueled shipping and ammonia-doped power generation. In 2060, the hydrogen required for emerging fields will reach 11.5 million tons, more than 50% of the total hydrogen demand in the ammonia industry. On the whole, the total demand for hydrogen in the synthetic ammonia industry has shown a trend of rising year by year and then fine-tuning and falling, from 10.8 million tons of hydrogen in 2019 to 25 million tons in 2050. Then, due to the withdrawal of coal power, the demand for ammonia-doped power generation decreased. In 2060, it will be reduced to 21.28 million tons. According to the forecast results of the model, with the advancement of technology, the reduction of the cost of renewable hydrogen, and the maturity of the carbon market, the main increase will be in emerging fields such as ammonia-fueled shipping and ammonia-doped power generation. In 2060, the hydrogen needed in emerging fields will reach 11.5 million tons, more than 50% of the total hydrogen demand in the ammonia industry.
4 Prediction of hydrogen energy supply structure in ammonia industry
4.1 ECONOMIC ANALYSIS
The total cost of my country’s current ammonia synthesis process using fossil fuels as raw materials includes the depreciation cost of fixed investment, operation and maintenance costs and raw material energy consumption costs. In order to better reflect the impact of different raw material substitutions on the economics of synthetic ammonia, and the depreciation costs and operation and maintenance costs of different processes are not much different, the differences in raw material and energy consumption costs are mainly considered. According to the relevant literature, the parameters of the economic analysis model are shown in Table 2, and the economic comparison of different processes is calculated in combination with the power electricity and cooling water required by different processes, as shown in Figure 13.
The cost of raw materials for the synthesis of ammonia from traditional fossil energy is based on the price of coal at 1400 CNY/t and the price of natural gas at 3.0 CNY/m3, the industrial electricity price is 0.56 CNY/kWh. Considering the carbon emissions of different processes, the comprehensive cost of each ammonia synthesis process is calculated with a carbon price of 500 CNY/t, as shown in Figure 13. Based on the assumption that the carbon market will mature in 2030 and the carbon price will reach 500 CNY/t, the coal-synthesized ammonia + CCS technology has an economic advantage over coal-synthesized ammonia, with an economical increase of 6%; the cost of natural gas-synthesized ammonia equipped with CCS remains almost unchanged. When the prices of hydrogen produced by renewable energy reach 23 yuan and 21.5 yuan respectively, the prices of green ammonia, coal-to-ammonia, and coal-to-ammonia+CCS remain the same; when the price of hydrogen further drops to around 21 yuan, the price of synthetic ammonia On par with natural gas ammonia production. According to the levelized cost analysis of renewable hydrogen in Figure 11, it is expected that renewable hydrogen will be competitive with fossil energy synthetic ammonia in 2030.
4.2 HYDROGEN SOURCE SUPPLY STRUCTURE OF SYNTHETIC AMMONIA INDUSTRY
At present, the hydrogen source of the synthetic ammonia industry mainly comes from non-low-carbon hydrogen such as coal gasification hydrogen production and natural gas reforming hydrogen production, all of which are used in traditional agricultural and industrial sectors. In the future, in the field of traditional ammonia synthesis, hydrogen production from water electrolysis by renewable energy will gradually become competitive. At the same time, considering that both renewable hydrogen and CCS technology economics will appear around 2030, and CCS technology is a transitional technology, industrial investment The enthusiasm is far lower than that of renewable energy electrolysis water hydrogen production technology, so this paper predicts that the existing non-low carbon hydrogen will be gradually replaced by renewable hydrogen. In the emerging application field of synthetic ammonia, its industrial deployment is mainly driven by decarbonization factors. The demand forecast in this paper is based on the development trend of the cost reduction of renewable hydrogen. Therefore, the hydrogen used for shipping ammonia fuel and ammonia power generation is all derived from renewable hydrogen. After 2030, the deployment of renewable hydrogen will accelerate. In 2035, renewable hydrogen will account for 20%. In 2040, renewable hydrogen will dominate the structure of hydrogen sources for ammonia synthesis. By 2060, the proportion of renewable hydrogen will reach more than 97%. . As shown in Figure 14. In terms of carbon emissions in the ammonia industry, the carbon emission trend of the ammonia industry is obtained according to the prediction results of the LEAP model of the hydrogen source supply structure, as shown in Figure 15. Under the accelerated cost reduction of renewable energy hydrogen production and the large-scale deployment of electrolyzed water installations, it is estimated that my country’s synthetic ammonia industry will reach its peak around 2030, with a peak carbon emission of 222 million tons of carbon dioxide. Since then, carbon emissions have been reduced year by year, and carbon emissions will drop to 9.2 million tons in 2060.
5 Conclusion
With the help of LEAP related models and methods, this paper realized the scenario analysis of the development of my country’s synthetic ammonia field based on the economic drive, carried out a simulation study on the implementation of the transformation of the synthetic ammonia industry under the permeability of different hydrogen source structures, and drew the following conclusions: (1) Green ammonia It is not yet economical in new terminal application scenarios such as ship transportation, power generation and heating. However, the preparation of green ammonia is economical (under the condition that the electricity price is within 0.3 CNY/kWh), which can give priority to the synthesis of green ammonia. In regions rich in renewable energy, priority will be given to the demonstration project of electrolytic water hydrogen production to ammonia synthesis, and more efforts will be made to develop key technologies and applications of electrolytic hydrogen production and mild ammonia synthesis, so as to realize the large-scale application of low-carbon ammonia synthesis technology as soon as possible. (2) The demand for hydrogen energy in the field of synthetic ammonia: With the reduction of the cost of renewable hydrogen, the maturity of the carbon market and the advancement of synthetic ammonia utilization technology, the synthetic ammonia industry has gained momentum in emerging fields such as shipping with ammonia as fuel and ammonia-doped power generation. freed. In 2060, the demand for synthetic ammonia will be 120 million tons, and the demand for hydrogen will be 21.28 million tons, of which the hydrogen needed in emerging fields will reach 11.5 million tons, exceeding 50% of the total hydrogen demand in the ammonia industry. (3) Contribution of renewable hydrogen to carbon emission reduction in the field of synthetic ammonia: my country’s synthetic ammonia industry has great potential to transform the energy supply structure from fossil energy to renewable energy. After 2030, the deployment of renewable hydrogen will accelerate. Around the peak, the peak carbon emission is 221.8 million tons of carbon dioxide. In 2035, renewable hydrogen will account for 20%, and in 2040, renewable hydrogen will dominate the structure of hydrogen sources for ammonia synthesis. By 2060, the proportion of renewable hydrogen will reach more than 97%, and carbon emissions will drop to 9.2 million tons. (4) Ammonia fuel ship technology is recognized globally as an important technical path to achieve carbon neutrality in the shipping industry. However, my country’s marine ammonia fuel engine technology research and development foundation is weak. Increase support for national key scientific and technological projects and major scientific and technological demonstration projects in this regard.