Overview of explosion protection in urban gas indu

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Overview of explosion-proof in urban gas industry I. classification of urban gas (I) urban gas is mainly divided into three categories: artificial gas, natural gas and liquefied petroleum gas, as well as mine gas and industrial tail gas. Artificial gas can be divided into four types: retort gas, gasified gas, oil gas and blast furnace gas. Urban gas is mainly classified according to their different sources. Artificial gas is classified according to its different production processes. (2) Composition of fuel gas ⑴ natural gas is a mixed gas mainly composed of methane and a small amount of ethane, propane, butane, propylene, hydrogen sulfide, carbon dioxide and other gases. Natural gas is divided into oil associated gas and gas field gas. Associated gas of oil: natural gas is extracted at the same time when oil is extracted. It consists of 80% methane, 2-5% propane and butane. The calorific value is 41860kj/m3. Gas field gas, the natural gas accumulated in the deposit, is almost entirely composed of methane, only a small amount of propane and butane. The calorific value is 33500-37600 kj/m3. Natural gas is the most ideal city gas with high calorific value and low impurity content. (2) the artificial gas is composed of a mixture of various gases, which is divided into two parts: combustible components and non combustible components. The combustible components include methane and ethane, which effectively ensure the accuracy of the experimental results, propane, propylene, hydrogen and carbon monoxide, etc; Non combustible components include carbon dioxide, nitrogen, oxygen, etc. The composition proportions of the above components are different for different gases such as dry distillation gas, gasified gas oil gas and blast furnace gas. The standard calorific value of artificial gas is 14650 kj/m3. (3) liquefied petroleum gas is mainly composed of propane, butane, isobutane, propylene, butene, isobutylene and other 8 hydrocarbons. The calorific value is 100460 kj/m3. General LPG has 4 specifications; With propane as the main component -- mainly composed of propane and propylene; Butane as the main component is mainly composed of n-butane. Attention should also be paid to the following points: butane, isobutane and isobutylene; Mixed liquefied petroleum gas - composed of C3 and C4 hydrocarbons in different proportions; However, due to the booming export of bauxite and the lack of strict environmental supervision, the environment of Malaysia has been greatly persecuted, which contains more than 95% propane. (3) The main state of urban gas is gas (LPG is liquid under certain conditions), so it has the properties of general gas, such as pressure, mass, specific gravity and density. However, urban gas has special properties different from other gases. The heat of combustion of urban gas is mostly more than 2.39mj/kg, which is several times higher than that of TNT explosive (0.39mj/kg), especially LPG, which has low boiling point and is very easy to vaporize. If it leaks suddenly, it will be vaporized instantly. Because its gas is heavier than air, it is not easy to diffuse, and it stays in a certain space to mix with air to form an explosive gas mixture, which is very dangerous. The combustion risk of LPG is greater than that of gasoline, and its combustion speed, flame propagation speed and flame surface radiation intensity are all twice that of gasoline. The explosion of gas and air mixture basically depends on whether the content of gas in the air reaches the explosion limit. Within the explosion limit, it will explode in case of fire source. See the table below for explosion range and minimum ignition temperature of urban gas. Table city gas explosion range and minimum ignition temperature table name gas content (v%) minimum explosion upper limit explosion lower limit ignition temperature (℃) natural gas 5.113.9645 coke oven gas 5.630.4300-500 producer gas 20.773.7530 LPG 1.59450-550


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