Development and Utilization of Hydrogen Energy

Hydrogen energy is the energy produced by the reaction of hydrogen and oxygen. Hydrogen energy is the chemical energy of hydrogen. Hydrogen appears on the earth mainly in the form of chemical compounds. It is the most widely distributed substance in the universe, and it constitutes 75% of the universe's mass and secondary energy. There are many ways to produce hydrogen in industry. The common ones are hydrogen production from water electrolysis, hydrogen production from coal gasification, hydrogen production from heavy oil and natural gas water vapor, and so on.



Development and Utilization of Hydrogen Energy

Hydrogen energy use in all aspects

There are many aspects of hydrogen energy use, some have already been realized, and some people are trying to pursue it. In order to achieve the goal of clean new energy, the use of hydrogen will be full of aspects of human life. Let us briefly describe the main uses of hydrogen energy from ancient times to the present.

Rely on hydrogen energy

In ancient times, Qin Shi Huang unified China. He wanted to live forever and he actively supported alchemy. In fact, the first contact with alchemists was hydrogen metal compounds. But how many emperors dreamed of being immortal, or dreaming of traveling in space, was constrained by the level of science and technology at that time. It was indeed a ladder. Later, in 1869, the famous Russian scholar Mendeleev organized the periodic table of chemical elements. He put hydrogen on the first place of the periodic table, and then proceeded from hydrogen, looking for the relationship with hydrogen, and laid the foundation for many elements. Basically, people are more scientific in the research and use of hydrogen. By 1928, Zeppelin AG had used the huge buoyancy of hydrogen to create the world’s first “LZ-127 Zeppelin” airship, which was the first time people had been transported from Germany to South America and had achieved a flight across the Atlantic. After about ten years of operation, the range of more than 160,000 kilometers, so that 1.3 million people received the taste of heaven, which is a miracle of hydrogen.

However, it is even more advanced that in the 1950s, the United States used liquid hydrogen as the fuel for supersonic and subsonic aircraft, which enabled the B57 twin-engine bomber to refit hydrogen engines and realized hydrogen-powered aircraft. In particular, 1957, former Soviet Union astronaut Gagarin traveled artificial earth satellites to travel in space, and in 1963 the U.S. spacecraft was launched. The spacecraft Apollo achieved the first man’s first assault on the moon in 1968. All this depends on the merits of hydrogen fuel. In the 21st century for science, the days of commercial operation of advanced high-speed long-range hydrogen aircraft and spacecraft are not far away. In the past, the dream of the emperor will be realized by modern people.

Use hydrogen energy to drive

The use of hydrogen instead of gasoline as the fuel for automobile engines has already been tested by many companies in Japan, the United States, and Germany, and the technology is feasible. At present, it is mainly the source of cheap hydrogen. Hydrogen is a highly efficient fuel, producing 33.6 kilowatt-hours of energy per kilogram of hydrogen, which is almost 2.8 times that of car combustion. Hydrogen combustion not only has a high calorific value, but also has a fast flame propagation speed and a low ignition energy (easy to spot). Therefore, the total fuel utilization efficiency of hydrogen vehicles can be 20% higher than that of gasoline vehicles. Of course, the main product of hydrogen combustion is water. There are only very few nitrogen oxides, and there are absolutely no harmful components that pollute the environment such as carbon monoxide, carbon dioxide, and carbon dioxide that are generated when gasoline is burned. Hydro-powered cars are the cleanest ideal vehicles.

The problem of hydrogen supply for hydrogen vehicles is that metal hydrides will be used as hydrogen storage materials. The heat required to release hydrogen gas may be provided by engine cooling water and waste heat of exhaust gas. There are two kinds of hydrogen cars, one is a full-hydrogen car, and the other is a hydrogen-fueled car that is mixed with hydrogen and gasoline. As long as the engine of a hydrogen-laden automobile is changed slightly or does not change, the fuel efficiency can be improved and the exhaust gas pollution can be reduced. Using a car with about 5% hydrogen, the average thermal efficiency can be increased by 15% and gasoline can be saved by about 30%. Therefore, the use of hydrogen-filled cars is more recently used. After hydrogen is available in large quantities, the hydrogen-fired cars will be promoted. The Mercedes-Benz company in Germany has launched a variety of hydrogen-burning cars, including vans, buses, postal cars and cars. Taking a hydrogen-fueled van as an example, 200 kg of titanium-iron-hydride hydride is used as a fuel tank, instead of a 65-liter fuel tank, it can drive over 130 kilometers continuously. The hydrogen-produced automobile manufactured by Mercedes-Benz company in Germany can be driven on the highway. The hydrogen storage tank used on the car is also a titanium-iron alloy hydride.

Hydrogenated vehicles are characterized by a mixture of gasoline and hydrogen fuel that can operate in a lean, lean area and improve the overall combustion of the engine. In the Chinese city of Xudang, traffic is congested, and automobile engines are mostly operated under partial load. It is particularly advantageous to use hydrogen-produced vehicles. In particular, some industrial residual hydrogen (such as ammonia production) cannot be recycled. If hydrogen is used as a hydrogen-containing fuel, both its economic and environmental benefits are desirable.

Burning hydrogen to generate electricity

Large-scale power stations, whether it is hydropower, thermal power or nuclear power, send the electricity sent to the power grid and deliver it to users. However, the load of various power consumers is different, and the power grid is sometimes peak and sometimes low. In order to regulate the peak load and the power grids often need to be started quickly and more flexibly, hydrogen power generation is best suited to play this role. Combustion with hydrogen and oxygen forms the oxyhydrogen generating set. This unit is a rocket-type internal combustion engine equipped with a generator, it does not require a complex steam boiler system, so the structure is simple, easy maintenance, quick start, open and open, want to stop. When the grid is under low load, it can also absorb excess electricity to carry out electrolyzed water production of hydrogen and oxygen in order to prepare for power generation at peak times. This adjustment is beneficial for running on a net. In addition, hydrogen and oxygen can directly change the operating conditions of conventional thermal power generating units and increase the power generation capacity of the power station. For example, hydrogen-oxygen combustion constitutes a magnetic fluid to generate electricity, and liquid hydrogen is used to cool the power generation device, thereby increasing the power of the unit and the like.

The newer way to produce hydrogen energy is hydrogen fuel cells. This is a device that uses hydrogen and oxygen (air) directly to generate electrical energy through electrochemical reactions. In other words, it is also the water electrolysis cell that produces a reverse reaction of hydrogen and oxygen. Since the 1970s, Japan, the United States, and other countries have stepped up research on various types of fuel cells and have now entered commercial development. Japan has established 10,000 kilowatt-class fuel cell power stations, and more than 30 US companies are developing fuel cells. Germany, Britain, France, More than 20 companies in Netherlands, Denmark, Italy, and Austria have invested in the research of fuel cells. This new type of power generation has attracted worldwide attention.

The simplest and most original method of the fuel cell is to convert the chemical energy of the fuel directly into electrical energy without burning, and the energy conversion efficiency can reach 60%-80%, and the pollution is small, the noise is small, the device can be large or small, and very flexible. In the earliest days, this kind of power generation unit was very small and costly. It was mainly used for aerospace as a power source. The price has been greatly reduced and gradually turned to ground applications. At present, there are many kinds of fuel cells, mainly the following:

Phosphate fuel cell

Phosphate fuel cells are the earliest type of fuel cell, and the process flow is basically mature. The U.S. and Japan have built commercial power stations with 4500 kilowatts and 11 thousand kilowatts respectively. The operating temperature of this fuel cell is 200°C, the maximum current density can reach 150 mA/cm2, the power generation efficiency is about 45%, the fuel is preferably hydrogen, methanol and the like, the oxidant is air, but the catalyst is platinum series, and the current power generation The cost is still high, about 40 to 50 cents per kilowatt-hour.

Fused Carbonate Fuel Cell

Fused carbonate fuel cells are generally called second-generation fuel cells. Their operating temperature is about 650°C, and their power generation efficiency is about 55%. Japan's Mitsubishi has already built a 10 kilowatt-class power generation unit. The electrolyte of the fuel cell is liquid. Due to the high working temperature, it can withstand the presence of carbon monoxide. The fuel can be hydrogen, carbon monoxide, natural gas, and the like. Air for oxidants. The cost of generating electricity can be less than 40 cents per kilowatt-hour.

Solid oxide fuel cell

Solid oxide fuel cells are considered to be third generation fuel cells. Their operating temperature is around 1000°C, and their power generation efficiency can exceed 60%. Currently, many countries are researching and it is suitable for the construction of large-scale power stations. The Westinghouse Company is developing. It is expected that the cost of power generation will be less than 20 cents per kilowatt-hour.

In addition, there are several types of fuel cells, such as alkaline fuel cells, operating temperatures of about 200°C, power generation efficiencies as high as 60%, and precious metals as catalysts. Sweden has developed a 200-kilowatt device for submarines. The first small-scale fuel cell used in the United States for the Apollo spacecraft is called the American type. It is an ion-exchange membrane fuel cell. Its power generation efficiency is as high as 75%, and its operating temperature is lower than 100°C. However, pure oxygen is required as an oxidant. Later, the United States developed a fuel cell for hydrogen vehicles, which can charge hydrogen for 300 kilometers at a speed of up to 100 kilometers per hour. This is a reversible proton exchange membrane fuel cell with a power generation efficiency of up to 80%.

The ideal fuel for fuel cells is hydrogen because it is the reverse reaction of hydrogen production by electrolysis. The main purpose of fuel cells is to be used as a power source for mobile power and vehicles, in addition to the establishment of a fixed power station. Therefore, it is also the twin brother of hydrogen energy utilization in the future.

Home hydrogen is convenient

With the development of hydrogen production technology and the lack of fossil fuels, the use of hydrogen energy will sooner or later enter the family. First, it is a developed large city. It can be sent to millions of households through the hydrogen pipeline just like the city gas. Each user uses a metal hydride storage tank to store hydrogen gas, and then connects kitchen stoves, bathrooms, hydrogen refrigerators, air conditioners, etc., respectively, and is connected to a car hydrogen charging device in a garage. People’s lives depend on a hydrogen energy pipeline that can replace gas, heating, and even power lines. Even gas stations for cars are saved. This clean and convenient hydrogen energy system will create a comfortable living environment for people and relieve many complicated tasks.

Hydrogen energy has a long history in the industrial field (such as cutting and welding). Especially in the jewelry processing industry, flame polishing of plexiglass products, cutting of continuous casting billets, and application of water injection and drawing seal in pharmaceutical plants are very popular.

As a new energy source, its safety has attracted widespread attention. Technically speaking, the use of hydrogen is absolutely safe. Hydrogen is highly diffusible in the air. When hydrogen leaks or burns, it can quickly rise vertically into the air and disappear without a trace. Hydrogen is not toxic and radioactive, and it does not harm the human body. Produces a greenhouse effect. Scientists have done a lot of hydrogen safety tests and proved that hydrogen is a safe fuel. For example, in a car ignition test, hydrogen and natural gasoline fuel tanks were respectively ignited. As a result, hydrogen gas burned violently after the hydrogen-fueled car fired. However, the flame always rushed upwards, causing relatively slow damage to the car. After a long time to escape, natural gas fueled the car. As natural gas was heavier than air, the flames spread around the car and quickly surrounded the car, hurting the safety of the people in the car.