A large category of petroleum products. A mixture of complex hydrocarbons (about 4 ~ 12 carbon atoms).
Colorless to yellowish flowable liquid. When the boiling point is about 30 ~ 205℃ and the gas content is 74 ~ 123 g/m3, it will explode. The main component is hydrocarbons with 4 to 12 carbons. Flammable.
The calorific value of gasoline is about 44000kJ/kg. The calorific value of fuel refers to the heat generated by the complete combustion of 1kg fuel.
prepare
It is prepared by petroleum fractionation or heavy distillation. Gasoline components are produced in crude oil distillation, catalytic cracking, thermal cracking, hydrocracking, catalytic reforming and other processes. The straight-run gasoline directly produced by crude oil distillation unit is not used as engine fuel alone, but is refined and blended, and sometimes additives (such as tetraethyl lead) are added to make commercial gasoline.
Classified use
One of the most commonly used light petroleum products is an important fuel for engines.
According to the manufacturing process, it can be divided into straight-run gasoline, thermal cracking gasoline, catalytic cracking gasoline, reforming gasoline, coking gasoline, superimposed gasoline, hydrocracking gasoline, cracked gasoline, alkylated gasoline and synthetic gasoline.
According to the purpose, it can be divided into three categories: aviation gasoline, vehicle gasoline and solvent gasoline. Mainly used as fuel for gasoline engines.
Widely used in automobiles, motorcycles, speedboats, helicopters, agricultural and forestry aircraft, etc. Solvent gasoline is used in rubber, paint, grease, perfume and other industries.
Important performance
The most important characteristics are evaporation resistance and explosion protection.
Evaporation refers to the difficulty of gasoline evaporation in carburetor. It has an important influence on engine starting, warming-up, acceleration, gas resistance and fuel consumption. Comprehensive evaluation of gasoline evaporation by distillation range, vapor pressure and gas-liquid ratio.
① Distillation range. Refers to the temperature range of gasoline fraction from the initial boiling point to the final boiling point. The distillation range of aviation gasoline is narrower than that of automobile gasoline.
② Steam pressure. Refers to the vapor pressure of 38℃ measured in standard instruments, which is an index reflecting the tendency of gasoline to generate gas resistance in the fuel system and the difficulty of engine starting.
Automobile gasoline needs higher vapor pressure, while aviation gasoline needs lower vapor pressure than automobile gasoline.
③ Gas-liquid ratio. Refers to the ratio of vapor volume to liquid volume of liquid fuel at a specified temperature and atmospheric pressure in a standard instrument. The gas-liquid ratio is a function of temperature, and it is more reliable to evaluate and predict the gas resistance tendency of gasoline than to use distillation range and vapor pressure.
Antiknock refers to the ability of gasoline to resist detonation combustion under various conditions of use. The antiknock performance of automobile gasoline is expressed by octane number. Octane number is given as follows: isooctane has good antiknock property, octane number is given as 100, and n-heptane has poor antiknock property, which is given as 0. The octane number of gasoline is determined by using isooctane and n-heptane as standard fuels, so that the detonation intensity produced by them is the same as that of the sample, and the volume percentage of isooctane in the standard fuel is the octane number of the sample. High octane number and good antiknock performance. The grades of gasoline are classified according to the octane number. High octane gasoline can meet the needs of high compression ratio gasoline engine. The higher the compression ratio of gasoline engine, the higher the thermal efficiency, which can save fuel. The antiknock ability of gasoline is related to its chemical composition. Branched alkanes, olefins and aromatics usually have excellent explosion resistance. Improving the octane number of gasoline mainly depends on increasing the components of high octane gasoline, but it can also be achieved by adding antiknock agents such as tetraethyl lead.
# Gasoline
# refers to the octane number index of gasoline. 90, 93, 97, 98.
The so-called 97 # gasoline is 97% isooctane and 3% n-heptane. If the compression ratio of the engine is high, high octane gasoline should be used. If the compression ratio is high, using low octane gasoline will cause abnormal combustion, leading to explosion, oil consumption and driving fatigue.
The label of gasoline only indicates the octane number of gasoline, and different labels of gasoline should be selected according to the different compression ratios of engines. A mid-range car with a compression ratio of 8.5-9.5 generally uses 93 # gasoline; Cars with compression ratio greater than 9.5 should use 97 # gasoline. At present, the compression ratio of domestic cars is generally above 9, and it is best to use 93 or 97 gasoline.
If the engine with high compression ratio uses low-grade gasoline, the cylinder temperature will rise sharply, the gasoline will burn incompletely, and the machine will vibrate strongly, thus reducing the output power and damaging the parts. If the engine with low compression ratio insists on using high-grade engine oil, it will have the phenomenon of "delayed combustion", that is, it will not reach the auto-ignition point even if it is pressed on the head, and it will also have the phenomenon of incomplete combustion, which is not good for the engine.
The higher the grade of the vehicle, the higher the requirements for fuel quality. For example, for mid-to high-end cars with more than 300,000 yuan, only No.95 or No.97 gasoline can be added. Here, No.95 and No.97 only represent the octane number energy in gasoline, but it does not mean that No.97 gasoline is cleaner than No.93 gasoline. High-end cars, on the cleanliness of gasoline requirements are extremely high. If the label of gasoline is not enough, the impact on vehicles will soon be shown, such as the phenomenon of acceleration weakness immediately after refueling; If there are too many impurities in gasoline, it will take some time to reflect the impact on the car, because the increase of carbon deposit or gum will affect the driving of the car to a certain extent.
The state has strict standards for motor gasoline. It not only requires gasoline to have a certain octane number (commonly known as gasoline label), but also has strict regulations on the content of various chemical components of gasoline. If the olefin content is too high, the car will not burn completely, resulting in a gelatinous substance that accumulates in the intake manifold and valve guide. When the engine is at normal working temperature, there is no abnormality; When the engine is turned off and cooled for a period of time, the glue will stick the valve in the valve guide. At this time, when the engine is started, the phenomenon of valve jacking will occur.
The higher the label, the better. The gasoline grade should be reasonably selected according to the compression ratio of the engine.
Among the parameters of automobile engines, most power-driven riders only pay attention to power and torque, while another important index is often ignored, that is, compression ratio. The compression ratio is the ratio of the maximum stroke volume to the minimum stroke volume of the piston in the cylinder, and it is also equal to the volume ratio of the top dead center and bottom dead center of the whole piston at different stroke positions. At present, most cars use so-called "reciprocating engines". To put it simply, in the cylinder of the engine, there is a piston that is repeatedly reciprocating in a straight line and has been circulating endlessly, so there is a certain range of motion strokes in this repeated working stroke. As far as a cylinder of the engine is concerned, when the stroke of the piston reaches the lowest point, the position point at this time is called the bottom dead center, and the volume formed by the whole cylinder including the combustion chamber is the maximum stroke volume; When the piston moves in the opposite direction to the highest point, this point is called top dead center, and the volume formed is the minimum volume of the whole piston movement stroke. The compression ratio to be calculated is the ratio of the maximum stroke volume to the minimum stroke volume. For example, an engine with a compression ratio of 10 compresses the combustible mixture to the original volume of110.
Generally speaking, the higher the compression ratio, the greater the power, the higher the efficiency and the better the fuel economy when the design of other engines remains unchanged. But if the compression ratio is too high, the stability will decrease and the engine life will be shortened. Moreover, the compression ratio can not be increased indefinitely, because the temperature of combustible mixture will rise sharply during compression. If the temperature exceeds the ignition point of the combustible mixture before reaching the top dead center of the piston, the combustible mixture will deflagrate, which is also commonly known as knocking on the cylinder, and obvious metal impact can be heard. Severe deflagration may even reverse the engine, causing fatal damage to the engine.
When the gasoline engine is running, the mixture of gasoline and air is inhaled. In the process of compression, the piston goes up, which not only squeezes the mixture to reduce its volume, but also produces two phenomena: vortex and turbulence. When the gas in the closed container is compressed, the pressure increases with the increase of temperature. If the compression of the engine is relatively high, the cylinder pressure and temperature generated during compression will also increase accordingly, and the gasoline in the mixture will vaporize more completely. In addition, under the action of high compression ratio, when the spark plug jumps out of the spark, the mixture can burn instantly, releasing energy and becoming the power output of the engine. On the contrary, if the combustion time is prolonged, the energy will consume and increase the temperature of the engine, instead of participating in the power output of the engine. Therefore, a high compression ratio engine means greater power output.
ethanol gasoline
Compared with the technical requirements of GB 17930- 1999 "Standard for unleaded gasoline for vehicles", the standard for ethanol gasoline for vehicles has the following characteristics: (1) The ethanol content is increased. The ethanol content is required to be in the range of 9.0% ~ 10.5% (v/v), and no other substances can be artificially added, but higher alcohols are allowed to be used as cosolvents. (2) 0. 15% (m/m) of mechanical impurities and moisture in the unleaded gasoline of the original vehicle.
As early as the 1920s, Brazil began to use ethanol gasoline. Because Brazil is short of oil resources, but rich in sugarcane resources, a set of technologies for producing sucrose and alcohol from sugarcane has been formed. At present, Brazil is the country that uses the most ethanol in the world, and the ethanol content in gasoline has reached 20%.
The United States is another big consumer of fuel ethanol in the world. Ethanol gasoline was first marketed in Nebraska in the 1930s. 1978 gasoline (E 10 gasoline) containing 10% ethanol is widely used in Nebraska. Since then, the federal government of the United States has implemented tax reduction or exemption for E 10 gasoline, and the fuel ethanol output has rapidly increased from 30,000 tons in 1979 to 2.69 million tons in 1990. In 2000, the output of fuel ethanol in the United States reached 5 million tons. With the decrease of MTBE usage in the United States and its final ban, fuel ethanol will become the best substitute for MTBE oxygenates. It is estimated that by 2004, the demand for fuel ethanol in the United States will reach100000 tons.
octane rating
Octane number is an index of gasoline antiknock and the most important quality index of gasoline. The label of automobile gasoline in China is determined by research method, and the octane number of No.93 gasoline is not lower than No.93, and so on. The engine should choose different grades of gasoline according to different compression ratios, which will be indicated in the user manual of each car. Too low gasoline label will cause knocking, engine power decline, car weakness and so on.
Actual colloid
The actual gum is an important index to evaluate the stability of gasoline, judge the tendency of gasoline to form gum in the engine, and judge whether gasoline can be used and stored continuously. According to the national standard, the actual gum content per 100 ml gasoline should not be greater than 5 mg. When the actual gum content of gasoline is too high, gum and carbon deposit will be produced during combustion, which will damage the engine. In severe cases, whether it is a hot car or a cold car, the engine will make abnormal noise and shake at idle speed, resulting in serious power shortage and even the engine can't start.
Cold filtration point
The cold filter point is an important index to measure the low temperature performance of light diesel oil. Specifically, it is the highest temperature at which diesel oil begins to block the engine filter screen under specified conditions. The cold filter point can reflect the actual performance of diesel oil at low temperature, which is closest to the actual minimum use temperature of diesel oil. When choosing a diesel brand, users should consider the local temperature and the cold filter point corresponding to the diesel brand. The cold filter point of No.5 light diesel oil is 8℃, No.0 light diesel oil is 4℃,-10 light diesel oil is -5℃, and -20 light diesel oil is-14℃.
flash(ing) point
Flash point is an index indicating the evaporation and safety performance of diesel oil. If the flash point is too low, it means that diesel oil is mixed with a little light oil, and the engine works rudely, which will bring great security risks to the storage, transportation and use of diesel oil and the safety after traffic accidents. Therefore, the flash point value strictly stipulated by the national standard is ≥55℃.
diesel engine
Diesel oil; Diesel fuel; diesel
Light petroleum products, complex hydrocarbon (about 10 ~ 22 carbon atoms) mixture. Diesel fuel. It is mainly made from diesel oil fractions produced in crude oil distillation, catalytic cracking, thermal cracking, hydrocracking, petroleum coking and other processes; It can also be made from shale oil processing and coal liquefaction. It is divided into light diesel oil (boiling point range is about 180 ~ 370℃) and heavy diesel oil (boiling point range is about 350 ~ 4 10℃). Widely used in large vehicles, railway locomotives and ships. The most important characteristics of diesel oil are flammability and fluidity. ① Flammability. High-speed diesel engines require that diesel can quickly form a uniform mixture with air after being injected into the combustion chamber, and immediately ignite and burn automatically, so the fuel is required to be easy to spontaneously ignite. The time interval from fuel injection into the cylinder to ignition is called ignition delay or ignition lag. If the self-ignition point of the fuel is low, the ignition delay time is short, that is, the ignition performance is good. Cetane number is generally used as an index to evaluate diesel spontaneous combustion. ② Liquidity. Freezing point is an important index to evaluate the fluidity of diesel oil, which indicates the lowest temperature at which fuel can be transported without heating. The freezing point of diesel oil refers to the highest temperature when oil is cooled to lose fluidity under specified conditions. Diesel oil has high content of n-alkanes, high boiling point and high freezing point. Generally, the freezing point of diesel oil is required to be 3 ~ 5℃ lower than the ambient temperature.
Liquid petroleum fraction with boiling point range and viscosity between kerosene and lubricating oil. It is a complex mixture with a boiling point range of 180? 370℃ and 350? 4 10℃. It is made of crude oil, shale oil, etc. By direct distillation or pyrolysis. According to the different properties of crude oil, there are paraffin-based diesel oil, naphthenic-aromatic-based diesel oil and so on. According to different densities, for petroleum and its processed products, it is customary to call those with low boiling point or low boiling point range light, and vice versa. Generally divided into light diesel oil and heavy diesel oil. Paraffin-based diesel oil is also used as raw material for cracking ethylene and propylene, and can also be used as absorption oil.
Commercial diesel oil is classified by freezing point, such as 10, -20, etc. , indicating low working temperature. Diesel oil is widely used in large vehicles and ships. It is mainly used as liquid fuel for diesel engines. Because high-speed diesel engines (automobiles) are more fuel-efficient than gasoline engines, the demand for diesel is growing faster than gasoline, and some small cars are also switching to diesel.
The main indexes are cetane number, viscosity and freezing point. The quality requirements for diesel oil are good combustion performance and fluidity. The higher the cetane number, the better. The cetane number of diesel oil made from annual crude oil can reach 68. The cetane number of light diesel oil used in high-speed diesel engine is 42? 55, low speed below 35.
Method for producing diesel oil; A method for synthesizing biodiesel from oil raw materials; Biodiesel prepared from animal oil and its preparation method: biodiesel and biofuel additive; Emulsifier for producing light diesel oil from waste animal and vegetable oil and its application: biomass liquefaction process and device with low cost and no pollution; Low-energy-consumption biomass pyrolysis process and device: a method for preparing biodiesel by rapid pyrolysis of microalgae: a depolymerization kettle for extracting gasoline and diesel from waste plastics, waste oil and waste vegetable oil residues, a method for preparing fuel gas by biomass gasification and a gasification reaction device; A method for extracting petroleum products from vegetable oil residues; A method for preparing synthesis gas by plasma pyrolysis of gasified biomass and a method for preparing biodiesel by hydrolyzing heterotrophic algae with amylase; A method for producing liquid fuel from biomass; The technological method of producing fuel oil from vegetable oil leftovers, the method of preparing bio-oil from biomass hydrolysis residues, and the production method of extracting gasoline and diesel from vegetable oil residues; Device and method for regenerating fuel oil from waste oil; Methods of removing colloid from FCC diesel oil: a new environmental protection process for refining fuel oil from waste rubber (waste plastics and waste engine oil), and a chemical refining method for total oxidized insoluble matter and colloid in diesel oil; Additives to prevent discoloration and gelation of diesel oil and gasoline; Flocculation separation treatment method of waste lubricating oil.
Vehicle diesel models: No.0,-10, -20, -35, Zheng No.5, Zheng 10, etc.