Hydrogen and nitrogen are directly combined to generate ammonia under a metal catalyst and certain temperature and pressure conditions. Synthetic ammonia is currently the second largest application for hydrogen after refineries. The most commonly used catalyst is based on iron and modified by K2O, CaO, SiO2 and Al2O3. The mixed gas usually passes through four catalyst beds and is cooled between each cooling bed to maintain a reasonable reaction equilibrium constant. Only about 15% of the gas is converted into ammonia each time it passes through a catalyst bed: the liquid ammonia is removed and the unreacted gas is recycled through the compressor. In modern factories, the total conversion rate can reach more than 97%. A 1,000 ton/day synthetic ammonia plant requires 336m3 of hydrogen for each ton of ammonia produced. The main cost of large-scale production of synthetic ammonia depends on the cost of hydrogen.

Methanol can be produced from synthesis gas (carbon monoxide and hydrogen) in a fixed-bed reactor with an alumina particle catalyst coated with copper and zinc oxides. Methanol can also be produced by the direct combination of hydrogen and carbon dioxide. In this process, hydrogen and carbon dioxide are pumped into the sealed chamber of the reaction vessel containing the catalyst and heated to 180-250°C. The maximum conversion of carbon dioxide to methanol is approximately 24%. Unconverted carbon dioxide and hydrogen are recovered and returned to the vessel. A methanol plant with a capacity of 2,500 tons/day requires approximately 560m3 of hydrogen for each ton of methanol produced.

1. In the petroleum refining process, hydrogen is mainly used for naphtha hydrodesulfurization, gas oil hydrodesulfurization, fuel oil hydrodesulfurization, improving the flameless height of aircraft fuel and hydrocracking;

2. Hydrocracking is a catalytic cracking process carried out in the presence of hydrogen. The main characteristics of the reaction are the breakage of C-C bonds, low space velocity, and a large amount of hydrogen used. In the petrochemical industry, hydrogen is mainly used for hydrogenation of C3 fractions, hydrogenation of gasoline, hydrodealkylation of C6-C8 fractions, and the production of cyclohexane.

1. Remove impurities such as sulfides, nitrogen compounds, lead and arsenic in naphtha.

2. The operating pressure of hydrodesulfurization of diesel fraction and heavy fraction is 3-4MPa, and the temperature is 340-380°C. Hydrodesulfurization of fuel oil is mainly due to environmental protection requirements, because 95% of air pollution is caused by SO2 released when fuel oil is burned. Hydrodesulfurization consumes a lot of hydrogen, so direct or indirect desulfurization can be used in the process.

3. Selective hydrogenation is mainly used for high-temperature cracking products. Gas-phase hydrogenation is used for the ethylene fraction, and liquid-phase hydrogenation is used for the propylene fraction. The gasoline fraction is rich in diolefins, olefins and aromatic hydrocarbons. These compounds are in contact with air. Colloids will be produced during the process, so hydrogenation must be carried out to convert unstable compounds into stable products.

The process of hydrogenation to remove harmful compounds. In addition to hydrogen sulfide, mercaptans, and total sulfur, alkynes, alkenes, metals, and metalloids can all be removed during the hydrogenation process. Therefore, in modern petrochemical processing, the use of hydrogenation technology can improve the quality of petrochemicals and increase the production of the most valuable petrochemicals. Reduce the generation of heavy oil residues and tar, reduce the amount of carbon deposits, and improve the efficiency of petroleum processing plants. With its adaptability, many valuable petrochemical products can be obtained from petroleum processing waste, purifying a series of products and removing harmful impurities. Hydrogen is the most common purifier and cross-linking agent for modern petrochemical industry products, and can improve the production capacity of large-scale cracking units.

In the field of petrochemical industry, hydrogen and carbon monoxide can be used to react to synthesize a variety of organic compounds, such as the synthesis of ethylene glycol, the synthesis of polymethylen (polymethylen), the homologation reaction of alcohols, the reaction with unsaturated hydrocarbons to produce aldehydes, etc. Various hydrocarbons can be synthesized using the Fischer-Tropsch method, including engine fuels and a series of valuable single organic compounds, such as solid paraffin, oxygenated compounds, etc.

1. Production of alcohols from aldehydes, production of alkenes from alkynes, production of benzene by dealkylation of toluene, production of aniline by hydrogenation of nitrobenzene, production of hydrogenated naphthalene from naphthalene, etc.

2. Diphenylmethylene diisocyanate (MDI), toluene diisocyanate (TDI), adipic acid, fatty alcohols, etc. used in the light chemical industry all require catalytic hydrogenation processes.

"In the crystal growth of electronic materials and the preparation of substrates, oxidation processes, epitaxial processes, and chemical vapor deposition (CVD) technology, hydrogen must be used as a reaction gas, reducing gas, or protective gas.

Oxidation process: When used for hydrogen-oxygen synthesis and oxidation, high-purity hydrogen and high-purity oxygen are passed into a quartz tube under normal pressure, causing them to burn at a certain temperature to generate high-purity water. The water vapor reacts with silicon to generate high-quality SiO2 membrane.

In the epitaxial process, silicon tetrachloride or trichlorosilane reacts with hydrogen on the surface of the heated silicon substrate to reduce the silicon and deposit it on the silicon substrate to form an epitaxial layer.

Chemical vapor deposition (CVD) technology: A method that uses one or several gas phase compounds or elements containing thin film elements to perform a chemical reaction on the surface of a substrate to form a thin film. Chemical vapor deposition is a new technology developed in recent decades for the preparation of inorganic materials. Chemical vapor deposition has been widely used to purify substances, develop new crystals, and deposit various single crystal, polycrystalline or glassy inorganic thin film materials. These materials can be oxides, sulfides, nitrides, carbides, or binary or multi-element interelement compounds in groups III-V, II-IV, IV-VI, and their physical functions can be passed through the gas phase. The doped deposition process is precisely controlled. "

The preparation of polysilicon in the electronics industry requires the use of hydrogen. When silicon uses hydrogen chloride to generate trichlorosilane SiHCl3, it is separated through a fractionation process. The purified trichlorosilane uses a high-temperature reduction process to reduce and deposit high-purity SiHCl3 in an H2 atmosphere to generate polysilicon. Its chemical reaction SiHCl3 H2→Si HCl reaches the purity required by semiconductors.

In the production process of electric vacuum materials and devices such as tungsten and molybdenum, oxide powder is reduced with hydrogen and then processed into wires and strips. If the purity of the hydrogen used is higher, the water content is lower, and the reduction temperature is lower. , the finer the tungsten and molybdenum powder obtained.

The filling gas purity requirements for various gas-filled electron tubes such as hydrogen thyristors, ion tubes, laser tubes, etc. are higher. The purity of hydrogen used in the manufacture of picture tubes is greater than 99.99%.

The production of semiconductor integrated circuits requires extremely high gas purity. For example, the allowable concentration of oxygen impurities is . The "incorporation" of trace amounts of impurities will change the surface characteristics of semiconductors and even reduce product yields or cause scrap.

High-purity hydrogen is also required in the manufacture of amorphous silicon solar cells. Amorphous silicon thin film semiconductor is a new material that has been successfully developed internationally in the past ten years and has shown attractive application prospects in solar energy conversion and information technology.

The application and development of optical fiber is one of the important symbols of the new technological revolution. Quartz glass fiber is the main type of optical fiber. During the manufacturing process, it is necessary to use hydrogen-oxygen flame heating and dozens of depositions to determine the purity and cleanliness of the hydrogen. All have very high demands.

Gases widely used in the glass industry are hydrogen, acetylene, oxygen and nitrogen. There is molten tin liquid in the float glass forming equipment. It is easily oxidized and generates tin oxide, causing the glass to be stained with tin and increasing the consumption of tin. Therefore, the tin bath needs to be sealed and pure hydrogen must be continuously supplied. Nitrogen mixed gas maintains positive pressure and reducing atmosphere in the tank to protect the tin liquid from oxidation. Hydrogen consumption in float glass plants depends on the production scale, generally between 80-150m3/h.

"The carbon emissions caused by the steel industry account for about 18% of my country's total carbon emissions.

Hydrogen steelmaking uses hydrogen as a reducing agent instead of carbon, thereby reducing carbon emissions from carbon reduction. It is aimed at the ironmaking process in the steel production process, that is, the blast furnace ironmaking in the long process and the direct reduction ironmaking in the short process. , in addition to eliminating carbon emissions from the reduction reaction, it can also eliminate carbon emissions from the coal coking process. According to the chemical formula of the carbon reduction iron reaction, the reducing agent carbon required to reduce 1 mol of iron is 1.5-3 mol (depending on the participation ratio of direct reduction and indirect reduction). According to the molar mass ratio of iron, carbon and carbon dioxide of 56:12:44, it is produced The carbon dioxide emissions produced by the carbon reduction reaction of 1 ton of iron are 0.59 tons, plus 0.1 tons of coking carbon emissions in the long process, which is equivalent to the long process theoretically reducing carbon emissions by about 0.69-1.28 tons, a reduction of 34-62% .

Blast furnace hydrogen-rich smelting and hydrogen-rich gas-based shaft furnace are the two main directions for the development of hydrogen metallurgy in my country. Compared with traditional "carbon metallurgy", hydrogen metallurgy can reduce carbon dioxide emissions by up to 85%. Hydrogenation of the steel industry will greatly contribute to carbon emission reduction.

Hydrogen enrichment of the blast furnace means injecting substances with higher hydrogen content into the blast furnace, such as pure hydrogen, natural gas, coke oven gas and other hydrogen-rich gases, to replace part of the carbon reduction and reduce carbon emissions. Hydrogen enrichment of the gas-based shaft furnace means increasing the proportion of hydrogen in the reducing gas in the gas base. "

"Hydrogen is mainly used as a reducing gas to reduce metal oxides to metals.

Hydrogen is used commercially to extract tungsten from ores (wolframite, scheelite, and wolframite). Can also be used to produce copper from chertite and chertite (copper oxide, CuO). "

When forging some metal equipment at high temperatures, hydrogen is often used as a protective gas to prevent the metal from being oxidized.

"Hydrogen is used to convert unsaturated fats into saturated oils and fats. For example, the food industry uses hydrogen to make hydrogenated vegetable oils such as margarine and butter.

Many natural edible oils have a high degree of unsaturation. After hydrogenation, the resulting product is stable for storage and resists the growth of bacteria and increases the viscosity of the oil.

The products of hydrogenated edible oil can be processed into margarine and edible protein. "

Hydrogenation of non-edible oils can produce raw materials for the production of soaps and livestock feeds. The process involves using hydrogen and unsaturated acids (oleic acid, linoleic acid, etc.) in glycerol to introduce hydrogen into the composition of liquid fats or vegetable oils.

It can meet many requirements for future aviation fuel. The most important thing is that hydrogen combustion causes basically no pollution to the environment. On a unit mass basis, the combustion heat value of hydrogen (119900-141900kJ/kg) is 1.8 times greater than the combustion heat value of hydrocarbon fuels. Propellants composed of liquid hydrogen and liquid oxygen have high specific thrust.

Hydrogen releases a large amount of heat when reacting with oxygen, and the combustion temperature can reach 3100K. When hydrogen passes through the arc flame, it decomposes into atomic hydrogen. The generated atomic hydrogen flies to the welding surface, and the metal is further heated and melted by absorbing the heat of atomic hydrogen. The temperature of the metal welding surface is as high as 3800-4300K. This atomic hydrogen can be used for melting and welding the most refractory metals, high carbon steels, corrosion-resistant materials, non-ferrous metals, etc. The advantage of using atomic hydrogen for welding is that the hydrogen atomic beam can prevent the welding part from being oxidized, so that no oxide scale will be produced in the welding place.

"Because hydrogen has a high thermal conductivity, hydrogen is often used as the rotor coolant in large generator sets.

Since hydrogen is a gas with an extremely low boiling point except helium, liquid hydrogen can obtain a low temperature of 14-15K when evaporated in a vacuum. Therefore, hydrogen is often used as a refrigerant in scientific research that requires ultra-low temperatures. "

Atomic hydrogen welding (AHW) is an arc welding process between two metal tungsten electrodes in a hydrogen protective atmosphere. It can be used to weld refractory metals and tungsten.

Hydrogen is one of the gases that can be used as a carrier phase in gas chromatography to separate volatile substances.

Due to its low density, hydrogen can be used to fill high-altitude weather balloons and airships.

"The transportation field is the most important application scenario of hydrogen energy. Hydrogen fuel cell vehicles are the entry point and key point for the promotion and application of hydrogen energy in the transportation field at this stage. In the short term, passenger cars and medium and light logistics vehicles will be the entry point, and in the medium and long term, hydrogen energy will be the entry point. Fuel heavy trucks are the main body.

Fuel cell vehicles are suitable for heavy-duty and long-distance transportation, and are more competitive in markets with high mileage requirements and large load capacity.

The future development direction is heavy-duty trucks, long-distance transportation passenger vehicles, etc. Fuel cell vehicles have more cost advantages in the transportation market with a cruising range of more than 650 kilometers. Since passenger cars and city buses often have shorter driving ranges, pure electric vehicles have advantages. Fuel cell vehicles overcome the problems of long energy replenishment time and poor adaptability to low-temperature environments, improve operating efficiency, and complement the application scenarios of pure electric vehicles. "

"Inland waterway and coastal shipping can be electrified through hydrogen fuel cell technology, and ocean shipping can be decarbonized through new fuels such as biofuels or zero-carbon hydrogen synthesis of ammonia.

Some enterprises and institutions in my country have started the development of hydrogen-powered ships based on the advancement of domestic hydrogen energy and fuel cell technology. At this stage, hydrogen-powered ships are usually used in lakes, inland rivers, offshore and other scenarios, as the main power for small ships or the auxiliary power for large ships. Large hydrogen-powered ships such as offshore engineering ships, offshore ro-ro ships, and super yachts are the future development trend. "

"Hydrogen energy provides the possibility for low-carbon aviation. Hydrogen energy can reduce the aviation industry's dependence on crude oil and reduce greenhouse and harmful gas emissions. Compared with fossil energy, fuel cells can reduce carbon emissions by 75%-90%. Direct combustion of hydrogen in gas turbine engines can reduce carbon emissions by 50%-75%, and synthetic fuels can reduce carbon emissions by 30%-60%.

Hydrogen-powered aircraft may become a carbon-reducing solution for short- and medium-distance aviation. "

"The application of hydrogen energy in the field of railway transportation is mainly to combine with fuel cells to form a power system to replace the traditional internal combustion engine. The advantage of hydrogen-powered trains is that there is no need to modify the existing railway tracks, the train is filled with hydrogen through a pump, and the noise is low , zero carbon emissions.

"Hydrogen refueling stations are the central link in the utilization and development of hydrogen energy. They are specialized places for refueling fuel cell vehicles. As the central link serving the commercial application of hydrogen energy transportation, they are important infrastructure for the development of the hydrogen energy industry.

Hydrogen from different sources is pressurized by a hydrogen compressor, stored in a high-pressure storage tank, and then filled with hydrogen for hydrogen fuel cell vehicles through a hydrogen filling machine. As a very critical link in the hydrogen energy strategy, hydrogen refueling stations radiate surrounding areas with their hydrogen fuel reserves, allowing vehicles to replenish energy in a timely manner and forming a good cycle to promote the development of fuel cells.

On the premise of ensuring safety, new models such as hydrogen refueling stations integrating hydrogen production, storage and refueling are also being actively explored. The "Medium and Long-term Plan for the Development of Hydrogen Energy Industry (2021-2035)" encourages full utilization The advantage of low production cost of on-site hydrogen production promotes the distributed production and nearby utilization of hydrogen energy. "

Hydrogen is produced by electrolyzing water from renewable energy sources such as photovoltaic power generation, wind power, and solar energy. Basically no greenhouse gases are produced during the hydrogen production process, so it is called "zero-carbon hydrogen."

"Pumped hydro storage accounts for more than 86% of electric energy storage. Hydrogen energy storage has the advantages of long discharge time, high cost-effectiveness of large-scale hydrogen storage, flexible storage and transportation methods, and will not damage the ecological environment. There are many application scenarios for hydrogen energy storage. On the power supply side, hydrogen energy storage can reduce power abandonment and smooth fluctuations; on the power grid, hydrogen energy storage can increase the peak capacity of the grid and alleviate transmission line congestion.

Hydrogen energy storage is currently mostly accomplished using alkaline electrolyzer technology combined with high-pressure gaseous hydrogen storage technology and proton exchange membrane fuel cells. Renewable energy storage and electricity-to-electricity conversion, energy conversion efficiency needs to be improved. Improve the efficiency of renewable energy storage by improving alkaline stack, electrode and separator materials, optimizing the design and manufacturing process of proton exchange membrane electrolyzers, and improving hydrogen storage efficiency by increasing hydrogen storage pressure and developing hydrogen liquefaction equipment and storage tanks. By 2025, an electricity-to-electricity conversion efficiency of 40-45% and a hydrogen storage density of 15-20 mol/L can be achieved. "

By utilizing the properties of metal hydrides that absorb hydrogen and release heat and dehydrogenate and absorb heat, a heat pump cycle or a thermal adsorption compressor can be established.

Utilizing the reverse reaction of electrolyzing water, hydrogen and oxygen (or air) undergo an electrochemical reaction to generate water and release electrical energy, which is "fuel cell technology". Fuel cells can be used in fixed or mobile power stations, backup peak power stations, backup power supplies, combined heat and power systems and other power generation equipment.

"Pure hydrogen or a mixture of hydrogen and natural gas can power gas turbines, thereby decarbonizing the power generation industry. There are two ways to generate electricity from hydrogen. One is to use hydrogen energy in gas turbines, which undergoes suction, compression, combustion, and exhaust. The hydrogen energy generator can be integrated into the power transmission line of the power grid and work in conjunction with the hydrogen production device to electrolyze water to produce hydrogen when electricity consumption is low. During peak hours, hydrogen energy is used to generate electricity, thereby rationalizing the application of electric energy and reducing resource waste. Hydrogen production using valley power is used at night, and renewable energy is used to produce hydrogen during the day, including photovoltaic power generation, including hydrogen production plants, public auxiliary devices, and storage. transportation engineering, environmental protection engineering, and filling functions."

Early use of hydrogen in buildings will primarily be in hybrid form. Hydrogen can be mixed with natural gas at a ratio of up to 20% by volume without the need to modify existing equipment or pipelines.

Compared with using pure hydrogen, blending hydrogen into natural gas pipelines can reduce costs and balance seasonal energy needs. As the cost of hydrogen falls, regions with natural gas infrastructure and access to low-cost hydrogen, such as North America, Europe and China, are expected to gradually use hydrogen in building heating and heating.

When the price of hydrogen is as low as 10-21 yuan/kg, it can compete with natural gas in distributed heating;

It is expected that by 2030, the demand for hydrogen energy from building combined heat and power generation will reach 30,000-90,000 tons/year; Det Norske Veritas DNV predicts that in the late 2030s, the use of pure hydrogen in buildings is expected to exceed that of mixed hydrogen; by In 2050, hydrogen will account for approximately 3-4% of the total energy demand for building heating and heating.