Combustion is a violent chemical reaction with both exothermic and luminous effects. Exothermia, luminescence and generation of new substances (such as carbon dioxide and water, leaving carbon and ash) are the three characteristics of combustion phenomenon. Combustion is an oxidation reaction, in which oxygen is the most common oxidant, but the oxidant is not limited to oxygen, and oxidation is not limited to combining with oxygen. The heat released by fuel combustion is still the main energy source of people, and its purpose is not to prepare products, but to obtain energy. Studying the conditions and methods of fuel full combustion is not only very important for saving energy and improving fuel utilization rate, but also of great significance for reducing the atmospheric pollution caused by harmful gases such as CO and soot produced by incomplete combustion. Generally speaking, the combustion of fuel in air is a redox reaction between fuel and oxygen in the air. In order to fully oxidize the fuel, we should ensure that there is enough air. At the same time, in order to ensure the full combustion of solid and liquid fuels, it is also an effective measure to increase the contact surface between fuel and air (solid fuel crushing, liquid fuel spraying in mist, etc.). ). Combustion condition: 1. Combustible (whether solid, liquid or gas, anything that can react violently with oxygen or other oxidants in the air is generally combustible, such as wood, paper, gasoline, alcohol, gas, etc. ) 2. Sufficient oxygen. The basic principles and methods to achieve material ignition and fire extinguishing: combustion must meet three conditions at the same time, and at least measures should be taken to destroy one of them. (2) Asphyxiation method: the combustion-supporting substance is diluted and suffocated to the extent that it cannot be burned, such as extinguishing the fire with inert gases such as nitrogen and carbon dioxide. (3) Isolation method: cut off the source of combustible gas, remove combustible substances, apply flame retardant, and cut off flame retardant substances, such as foam extinguisher for oil fire. Common fuels in the world today: coal, oil and natural gas are the three most important fossil fuels in the world today, and they are also extremely important raw materials in the chemical industry. They are subdivided into (1) solid fuels: firewood, smoked coal, bare coal, anthracite, charcoal, coke, pulverized coal, etc. (2) Liquid fuel; Gasoline, kerosene, diesel, heavy oil, etc. ; (3) Gas fuels: natural gas, artificial gas, liquefied petroleum gas and other clean fuels: the development and utilization of marine resources such as liquid ammonia, alcohol, liquid hydrogen (the cleanest fuel, the combustion product is water) and methanol and the marine environment. The ocean is rich in resources. Nowadays, the contradiction between the shortage of global food, resources and energy supply and the rapid population growth is increasingly prominent, and the development and utilization of rich marine resources is an inevitable trend of historical development. At present, the marine resources developed and utilized by human beings mainly include marine chemical resources, marine biological resources, seabed mineral resources and marine energy. Seawater can be directly used as industrial cooling water source and inexhaustible seawater desalination water source. Developing seawater desalination technology and obtaining fresh water from the ocean is one of the important ways to solve the shortage of fresh water in the world. More than 80 chemical elements have been found in seawater. At present, the development of marine chemical resources has reached industrial scale, including salt, magnesium, bromine and fresh water. With the development of science and technology, rich marine chemical resources will benefit mankind widely. There are more than 200,000 species of life in the ocean, including 6,543,800 species of animals and 6,543,800 species of fish. In ancient times, humans began to catch and collect seafood. Now, human marine fishing activities have expanded from offshore to various sea areas in the world. The improvement of fishing gear, fishing boat and fish exploration technology has greatly improved the marine fishing ability of human beings. Marine biological resources are composed of fish, shrimp, shellfish and algae, which can be directly fished for food and medicine, and can also be continuously utilized through cultivation and proliferation. There are abundant mineral resources such as oil, natural gas, coal, sulfur and phosphorus buried in the shallow sea bottom of the continental shelf. The coastal placer in the nearshore zone is rich in building materials and metal minerals such as sand and shells. Deep-sea manganese nodules are widely distributed in most ocean basins and are the most potential metal mineral resources in the future (Figure 3. 14 Deep-sea manganese nodules). Seawater movement contains huge energy, which belongs to renewable energy and has no pollution. However, these energy densities are very small, and special energy conversion devices must be adopted to develop and utilize them. At present, tidal power generation and wave power generation have commercial development value, but the project investment is large and the benefit is not high. Marine fishery production marine fishery resources are mainly concentrated in the coastal continental shelf, that is, the part of the mainland seabed extending from the coast to about 200 meters underwater. Here, the sunshine is concentrated, the photosynthesis of organisms is vigorous, and the rivers entering the sea bring rich nutrients, so plankton is flourishing (Figure 3. 15 Schematic Diagram of Continental Shelf Profile). These plankton are the bait of fish, and their distribution in the ocean is very uneven, usually in temperate waters. The seasons in temperate regions vary greatly. When surface seawater and bottom seawater are exchanged in winter, the submerged bottom seawater is rich in nutrients, which come from decaying biological debris in the ocean. At the intersection of warm current and cold current, or where there is cold seawater flooding, the bait is rich. These places are usually fishing grounds (Figure 3. 16 Distribution of major fishing areas in the world). Therefore, although the continental shelf waters only account for 7.5% of the total ocean area, the catch accounts for more than 90% of the total ocean catch in the world. The main fishing countries in the world are located in temperate regions, where the consumption of fish products is high and the market demand is large. China and Japan are countries with a large amount of marine fishing in the world. China has made full use of offshore fishing grounds (Figure 3. 17 "Zhoushan Fishing Ground and shenjiamen Fishing Port") and shallow beaches to vigorously develop marine fishing and mariculture, while offshore fishing has also made great progress. Japan has limited arable land and high population density, so seafood accounts for a large proportion in the food structure. Offshore oil and gas development The development of submarine oil and gas began in the early 20th century. Its development has gone through the process from offshore to offshore and from shallow sea to deep sea. Limited by technical conditions, only oil and gas deposits extending directly from the coast to the shallow sea can be mined at first. Since the 1980s, stimulated by the energy crisis and technological progress, offshore oil exploration and development have developed rapidly, and offshore oil development has rapidly advanced to the continental shelf, gradually forming a brand-new offshore oil industry sector. Geologists and geophysicists usually use seismic wave method to find submarine oil and gas deposits, and then estimate the types and distribution of mineral deposits through offshore drilling to analyze whether they have commercial development value. Offshore drilling platform (Figure 3. 18 "Offshore Drilling Platform") is the working base for offshore oil and gas exploration and development, which indicates the level of offshore oil and gas development technology. The transportation of personnel and materials between the platform and the land is generally completed by helicopters. Oil and gas fields are generally far from refineries, and oil and gas should be shipped to their destinations through oil loading stations or directly transported to the coast by submarine pipelines. The exploration and development of submarine oil and gas is a project with high investment, high technical difficulty and high risk, and international cooperation and project bidding are one of the feasible ways. The rapid growth of the world population makes the land space more and more crowded, and the development and utilization of marine space is paid more and more attention. The available space of the ocean includes three parts: the ocean, the middle of the ocean and the seabed. With the gradual advance of mankind to the ocean, the ocean will become a vast space for human activities (Figure 3. 19). The marine environment is different from the land, and its environmental and ecological conditions are complex and special. Human activities are at the seaside, on the surface of the ocean, and need to resist the changeable meteorological conditions of the ocean and the movement of seawater; Deep-sea activities should be able to adapt to the dark, high pressure, low temperature and anoxic environment; Seawater is corrosive and sea ice is destructive, so there are strict requirements for materials and structures of engineering equipment. Therefore, the development of marine space resources is highly dependent on science and technology and capital investment, which is technically difficult and risky. The utilization of marine space has expanded from traditional transportation to many fields such as production, communication, power transmission, storage, culture and entertainment. Traffic includes seaports, ships, waterways, undersea tunnels, bridges, airports and pipelines. The production space includes offshore power station, industrial artificial island, offshore oil city, land reclamation, marine pasture, etc. Communication and power transmission space is mainly submarine cables. As far as storage space is concerned, there are submarine freight yards, submarine warehouses, offshore oil depots and marine waste treatment plants. Cultural and recreational facilities include marine parks, bathing beaches and marine sports areas.

The content may be a little too much, but it is comprehensive. I hope it will be adopted by you.