I. Introduction of Hydrogen Energy
As the existing main fuels, the production of gasoline and diesel depends almost entirely on fossil fuels. With the increasing consumption of fossil fuels, their reserves are decreasing, and these resources will be exhausted one day. Therefore, it is urgent to find a new type of energy that is independent of fossil fuels and rich in reserves. Hydrogen energy is a kind of new energy that people expect when the conventional energy crisis appears and new energy is developed.
Hydrogen is at the top of the periodic table, and its atomic number is 1. It is gaseous at normal temperature and pressure, and can become liquid at ultra-low temperature and high pressure. As an energy source, hydrogen has the following characteristics:
1. Of all the elements, hydrogen is the lightest. In the standard state, its density is 0.0899 g/L; At -252.7℃, it can become liquid. If the pressure is raised to several hundred atmospheres, liquid hydrogen can become solid hydrogen.
2. Among all gases, hydrogen has the best thermal conductivity, which is 10 times higher than that of most gases, so hydrogen is an excellent heat transfer carrier in energy industry.
Hydrogen is the most common element in nature. It is estimated that it accounts for 75% of the mass of the universe. Except hydrogen in the air, it is mainly stored in water in the form of compounds, and water is the most widely distributed substance on the earth. It is estimated that if all the hydrogen in seawater is extracted, the total heat generated is 90O0 times greater than that released by all fossil fuels on the earth.
4. The calorific value of hydrogen is the highest among all fossil fuels, chemical fuels and biofuels except nuclear fuel, which is 142 438+0kJ/kg, three times that of gasoline.
5. Hydrogen has good combustion performance, fast ignition, wide combustible range when mixed with air, high ignition point and fast combustion speed.
6. Hydrogen itself is non-toxic. Compared with other fuels, hydrogen burns cleanest. Except water and a small amount of hydrogen nitride, it will not produce pollutants harmful to the environment, such as carbon monoxide, carbon dioxide, hydrocarbons, lead compounds and dust particles. A small amount of hydrogen nitride will not pollute the environment after proper treatment, and the water produced by combustion can continue to produce hydrogen and be recycled.
7. There are many uses of hydrogen, which can generate heat energy through combustion and mechanical work in a heat engine, and can also be used as an energy material for fuel cells, or converted into solid hydrogen as a structural material. Replacing coal and oil with hydrogen does not require a major transformation of the existing technical equipment, and the current internal combustion engine can be used with a little transformation.
8. Hydrogen can appear in the form of gaseous, liquid or solid metal hydride, which can meet the different requirements of storage and transportation and various application environments.
It can be seen from the above characteristics that hydrogen is an ideal new energy source. At present, liquid hydrogen has been widely used as fuel for aerospace power, but the large-scale commercial application of hydrogen energy still needs to solve the following problems:
1. Cheap hydrogen production technology. Because hydrogen is a kind of secondary energy, its preparation not only consumes a lot of energy, but also the efficiency of hydrogen production is very low at present, so it is a common concern of scientists all over the world to seek large-scale and cheap hydrogen production technology.
2. Safe and reliable hydrogen storage and transmission methods. Because hydrogen is easy to vaporize, catch fire and explode, how to properly solve the problem of storage and transportation of hydrogen energy has become the key to the development of hydrogen energy.
Many scientists believe that hydrogen energy may become an important energy source on the world energy stage in 2 1 century. Hydrogen energy is a kind of secondary energy, because it is produced by other energy sources in a certain way, unlike coal, oil and natural gas, which can be directly mined from underground. In nature, hydrogen combines with oxygen to form water, and hydrogen must be separated from water by thermal decomposition or electrolysis. It is obviously not feasible to use the heat generated by the combustion of coal, oil and natural gas or the converted electrolyzed water to produce hydrogen. Now it seems that the basic way to produce hydrogen efficiently is to use solar energy. If we can use solar energy to produce hydrogen, it is equivalent to converting endless and scattered solar energy into highly concentrated clean energy, which is of great significance. At present, the methods of using solar energy to decompose water to produce hydrogen include solar thermal decomposition of water to produce hydrogen, solar electrolytic water to produce hydrogen, solar catalytic photolysis of water to produce hydrogen, solar biological hydrogen and so on. Hydrogen production from solar energy is of great practical significance, but it is a very difficult research topic, and there are a lot of theoretical and engineering problems to be solved. However, all countries in the world attach great importance to it, invest a lot of manpower, financial resources and material resources, and have made various progress. Therefore, in the future, hydrogen energy made from solar energy will become a high-quality clean fuel widely used by human beings.
Two. Application and prospect of hydrogen
As early as the Second World War, hydrogen was used as a liquid propellant for the A-2 rocket engine. Liquid hydrogen was used as space power fuel for the first time in 196O. The take-off rocket used by the Apollo spacecraft launched by the United States in 1970 also used liquid hydrogen as fuel. Now hydrogen is a common fuel in rocket field. For the modern space shuttle, it is more important to reduce the self-weight of fuel and increase the payload. The energy density of hydrogen is very high, which is three times that of ordinary gasoline, which means that the self-weight of fuel can be reduced by two-thirds, which is undoubtedly very beneficial to the space shuttle. today
The space shuttle uses hydrogen as the propellant of the engine, pure oxygen as the oxidant, and liquid hydrogen is packaged in an external propellant barrel to form a fuel cell. Each launch requires H2 1450 m3 and weighs about 100t. The reaction equation is as follows: (using sodium hydroxide as electrolyte)
Negative electrode: 2h2-2e-+2oh-= 2h2o
Positive electrode: O2+4e-+2h2o = 4oh-
Total reaction equation: 2h2+O2 = 2h2o.
Now scientists are studying a "solid hydrogen" spacecraft. Solid hydrogen is not only used as structural material of spacecraft, but also as power fuel of spacecraft. During the flight, all non-important components on the spacecraft can be converted into energy and "consumed". In this way, the spacecraft can fly in the universe for a longer time.
Daimler-Benz's hydrogen-fueled vehicle has been studied on supersonic aircraft and long-range intercontinental passenger aircraft for many years, and has now entered the prototype flight test stage. In terms of transportation, the United States, Germany, France, Japan and other major automobile countries have already launched demonstration vehicles fueled by hydrogen and conducted hundreds of thousands of kilometers of road tests. Among them, the United States, Germany, France and other countries use hydrogenated metals to store hydrogen, and Japan uses liquid hydrogen. Experiments show that cars fueled with hydrogen have good prospects in economy, adaptability and safety, but there are still two obstacles: low hydrogen storage density and high cost. The former limits the continuous driving distance of the car, while the latter is mainly caused by the high cost of the liquid hydrogen supply system. The United States and Canada joined forces to use liquid hydrogen as fuel on railway locomotives. After further research, locomotives burning liquid hydrogen and liquid oxygen will run on the continental railway from western Canada to eastern Canada.
Hydrogen is not only a high-quality fuel, but also an important raw material and material for petroleum, chemical industry, fertilizer and metallurgical industry. The refining of petroleum and other fossil fuels requires hydrogen, such as hydrogen enrichment of hydrocarbons, gasification of coal, refining of heavy oil, etc. In the chemical industry, hydrogen is also needed to make ammonia and methanol. Hydrogen is also used to reduce iron ore. Hydrogen fuel cells can directly generate electricity. Using fuel cell and hydrogen-steam combined cycle to generate electricity, its energy conversion efficiency will be much higher than that of existing thermal power plants. cladus
With the progress of hydrogen energy technology and the improvement of hydrogen storage means, hydrogen energy will show its elegance on the energy stage of 2 1 century.
White pollution becomes fuel oil.
The mountains of plastic garbage and plastic food bags flying around the city can be recycled and smelted into gasoline and diesel. After more than 8 years of research and pilot test, Beijing Menglan Solid Waste Recycling Company has successfully solved the key problems such as coking, slag discharge and temperature control in the oiling process of waste plastics, and developed its own process system and complete sets of equipment. The National Petroleum Product Quality Supervision and Inspection Center has strictly tested the samples submitted by the company, and determined that they meet the national standards for vehicle fuels and environmental emission standards. Relevant experts suggest organizing popularization and application as soon as possible to alleviate the environmental crisis caused by white pollution.
For many years, the disposal methods of waste plastics at home and abroad are generally landfill and incineration. However, the research shows that waste plastics can only be decomposed after more than 200 years of landfill, and toxic substances will be dissolved in the process of decomposition, which is easy to destroy the soil; Incineration will release harmful gases into the air, affecting the atmospheric environment and surrounding environment. Beijing Menglan Solid Waste Recycling Technology Co., Ltd. believes that the catalytic cracking of waste plastics into fuel is an important way to recover substances and avoid secondary pollution, which represents the treatment direction of waste plastics. Practice has proved that the equipment using this technology has strong daily processing capacity of waste plastics and high conversion rate of gasoline and diesel oil under continuous production conditions, which meets the vehicle fuel and environmental emission standards.
Combustible ice-the new hope of human energy
The scientific name of combustible ice is "natural gas hydrate", which is an "ice cube" crystallized from natural gas at 0℃ and 30 atmospheric pressure. Methane accounts for 80% and 99.9% of "ice" respectively? Future energy ".
1 m3 combustible ice can be converted into 164 m3 natural gas and 0.8 m3 water. Scientists estimate that the distribution of combustible ice on the seabed is about 40 million square kilometers, accounting for 10% of the total ocean area, and the reserves of combustible ice on the seabed are enough for human use 1000 years.
With the deepening of research and investigation, the number of combustible ice found in the world's oceans has gradually increased, with 57 on the seabed in 1993 and 88 on the seabed in 200 1. According to exploration estimation, the combustible ice resources of Black Ridge in the southeast coast of the United States are as high as1800 million tons, which can meet the natural gas consumption of the United States 105. The combustible ice resources in the Sea of Japan and its surrounding areas can be used by Japan for more than 0/00 years.
According to experts' estimation, the world's total oil reserves are between 270 billion tons and 650 billion tons. According to the current consumption rate, the world oil resources will be exhausted in another 50-60 years. The discovery of combustible ice has brought new hope to mankind caught in the energy crisis.
Joint investigation under great strategic significance
On June 2 this year, 26 Chinese and German scientists boarded the German scientific research ship Susafeng from Hong Kong and began a 42-day comprehensive geological survey of the South China Sea. Through submarine TV observation and submarine TV monitoring grab sampling, giant carbonate rocks with an area of about 430 square kilometers were discovered for the first time.
Chinese and German scientists unanimously suggested that one of the most typical structures in this authigenic carbonate area be named "Jiulong Methane Reef". Among them, the word "Dragon" stands for China, and "Nine" stands for the cooperation of several research groups. Isotopic dating analysis shows that the carbonate crust in the "Jiulong methane reef" area was first formed about 45 thousand years ago and is still releasing methane gas.
Huang Yongyang, chief scientist of China and chief engineer of Guangzhou Marine Geological Survey, was very excited about this. He said that the detection evidence shows that the combustible ice reserves in the northern part of the South China Sea alone account for about half of the total onshore oil in China; In addition, the distribution area of combustible ice has been preliminarily delineated in Xisha Trough, and the estimated resource amount is 4. 1 trillion cubic meters.
China has become a pure oil importer since 1993. It is estimated that by 20 10, the net oil import will increase to about10 billion tons, and will increase to about 200 million tons in 2020. Therefore, it is of great strategic significance to understand the background of combustible ice and develop combustible ice resources for China's subsequent energy supply and sustainable economic development.
Huang Yongyang introduced that in the next decade, China will invest 8 1 100 million yuan to conduct a resource survey of this new energy source. It is expected that the properties of combustible ice will be found out around 2008, and combustible ice will be tested and mined in 20 15 years.
A "double-edged sword" created by strategy and danger.
So far, at least more than 30 countries and regions in the world are conducting research, investigation and exploration of combustible ice.
1960, the first combustible ice gas reservoir was discovered in Siberia by the former Soviet Union. 1969 was put into development, producing gas 14 years, with a total gas production of 50170,000 cubic meters.
The investigation of combustible ice began in America 1969. 1998 combustible ice was included in the national long-term plan as a strategic energy source for national development, and it is planned to conduct commercial trial mining by 20 15.
Japan pays attention to combustible ice in 1992. At present, the investigation and evaluation of combustible ice in the surrounding waters have been basically completed. Seven exploratory wells have been drilled, and 12 ore concentration area has been delineated, and combustible ice samples have been successfully obtained. Its goal is to conduct commercial trial mining on 20 10.
However, mankind still faces many new problems when exploiting combustible ice buried in the deep sea. Some scholars believe that the role of methane in global warming is 20 times greater than that of carbon dioxide. Even the smallest damage to combustible ice deposits is enough to cause a large amount of methane gas leakage. In addition, it is very difficult to mine combustible ice on the coast of continental margin. Once a blowout accident happens, it will lead to tsunami, submarine landslide, seawater poisoning and other disasters.
It can be seen that combustible ice is not only a new energy source in the future, but also a dangerous energy source. The development and utilization of combustible ice is like a "double-edged sword", which needs to be treated with care.
The background of the news story
Qiangtang basin may be rich in combustible ice.
After years of research on the Qinghai-Tibet Plateau, frozen soil experts in China believe that the permafrost region of Qiangtang Basin on the Qinghai-Tibet Plateau has the temperature and pressure conditions to form natural gas hydrate, which may contain a lot of combustible ice.
According to Wu, a researcher at the Institute of Environment and Engineering in Cold and Arid Regions, Chinese Academy of Sciences, the Qinghai-Tibet Plateau is a plateau permafrost region with the youngest mid-latitude and the highest altitude, with deep Carboniferous, Permian, Tertiary and Quaternary sediments, and high organic matter content in marine sediments of rivers and lakes. The Quaternary suffered from extensive glacier-periglacial action with the strong uplift of the plateau, and the ice sheet pressure enhanced the stability of natural gas hydrate in the underlying sediments, especially in Qiangtang Basin and Tianshuihai Basin, and it is entirely possible to have the conditions for the stable existence of combustible ice.
Combustible ice, also known as natural gas hydrate, is solid natural gas, which widely exists on the earth, and its reserves are estimated to be 2.6 times of conventional reserves. It is also a clean energy source, and combustion will hardly produce harmful pollutants. This makes the development and utilization of this material, which is expected to become a new energy upstart in the new century, in full swing.
China is the third largest country in the world in terms of frozen soil area, accounting for about 10% of the world's frozen soil area, of which the frozen soil area of Qinghai-Tibet Plateau accounts for 7% of the world's frozen soil area. In 1960s and 1970s, Lanzhou Institute of Glacier and Frozen Soil of Chinese Academy of Sciences drilled in Qilian Mountain frozen soil area at an altitude of 4,000 meters and Wudaoliang frozen soil area of Qinghai-Tibet Plateau at an altitude of 4,700 meters, respectively, and found a lot of signs and phenomena similar to natural gas hydrate. The results of large-scale geophysical exploration conducted by Wuhan Branch of China Geo University and the Fifth Geophysical Brigade of Central South Petroleum Bureau in Qiangtang Basin of northern Tibet Plateau show that Tibet may become the second strategic replacement area of petroleum resources in China in 2 1 century after Tarim Basin.
Wu Shuo, at present, they are carrying out a plan to find combustible ice, and have begun to do a lot of preliminary work in the laboratory. After that, they will study the search for natural gas hydrate in Qiangtang basin in three steps, and if it does exist, study its distribution law and basic properties; Estimated reserves and research and development prospects; Research on mining technology and environmental protection. "But this is a long period, at least 10 years." "Once these combustible ice are discovered, it will have important theoretical significance and broad application prospects for China's macro-energy strategic decision-making, opening up new disciplines and maintaining the sustainable development of human society."