Application and selection of combustible gas detectors
Before we choose a combustible gas detector, we must first understand which are combustible gases. The more common combustible gases in our daily life are: natural gas, liquefied petroleum gas, biogas, gas, coal gas
natural gas
The main component of natural gas is methane, and also contains a small amount of ethane, butane, pentane, carbon dioxide, carbon monoxide, hydrogen sulfide, etc. The specific gravity is 0.65, which is lighter than air, and has the characteristics of colorless, odorless and non-toxic. Natural gas companies all add odorants in accordance with government regulations, so that users can smell them. It is lighter than air. Generally, the way we install it is 30-60cm above the ceiling, and heavier than air, and it is installed 30-60cm below.
Natural gas is generally used in: Civil fuel: natural gas has low price, high calorific value, good safety performance and good environmental performance. It is the fuel for civil gas. Industrial fuel: Substitute natural gas for coal for factory heating, production boilers and gas turbine boilers in thermal power plants. Process production: such as paint production line, tobacco drying, asphalt heating and heat preservation, etc.
liquefied petroleum gas
Liquefied petroleum gas is obtained from petroleum processing or oil and natural gas extraction, and its main components are propane, propylene, butane and butene. Gaseous liquefied petroleum gas is heavier than air, and its specific gravity is 1.5-2 times that of air. It needs to be installed at the bottom 30-60CM
When the concentration of liquefied petroleum gas in the air is high, it has an anesthetic effect on the central nervous system of people. If the combustion is incomplete, it will produce toxic gases such as carbon monoxide. LPG has a peculiar odor that can be detected when it leaks. Liquefied petroleum gas is flammable and explosive after mixing with air. When the concentration of liquefied petroleum gas in the air reaches 1.5-9.5%, it will explode when it encounters fire, so leakage must be prevented. When liquefied petroleum gas is completely burned, a large amount of air is required to assist the combustion.
Biogas
Biogas is a kind of combustible gas produced by organic matter under the condition of isolating air and certain temperature, humidity, pH, etc. through the action of biogas bacteria. Since this gas was first discovered in swamps, it is called biogas. The main components of biogas are methane, the rest are carbon dioxide, oxygen, nitrogen and hydrogen sulfide. Among them, the methane content is about 55% to 70%, and the carbon dioxide content is about 30% to 45%. Biogas is a mixed gas.
gas
The main component of gas, methane, is a flammable gas, colorless, odorless, insoluble in water, and less dense than air. After mixing with oxygen or air, it is easy to explode in a certain space when it reaches a certain temperature.
gas
The main components of coal gas are carbon monoxide, hydrogen and alkanes, olefins, aromatic hydrocarbons, etc. Coal gas is poisonous because the carbon monoxide and aromatic hydrocarbons in it can combine with hemoglobin in the human body, resulting in hypoxia, making people unconscious or even dying. At low concentrations, it can also make people dizzy and collapse. Therefore, special care should be taken when using gas, and gas pipelines, stoves and related valves should be checked frequently, and the valves should be tightly closed after each use to prevent leakage.
The selection should be targeted, and each unit encounters different types of gases in production, so all possible situations must be considered when selecting a gas detector. If there are many methane and other less toxic alkanes, and if there are toxic gases such as carbon monoxide and hydrogen sulfide in the production, it is necessary to choose a specific gas detector to ensure the safety of workers. If there are more organic toxic and harmful gases, considering that other concentrations that may cause human poisoning are low, such as aromatic hydrocarbons, halogenated hydrocarbons, ammonia, ethers, alcohols, fats, etc., photoionization detectors should be selected. If the gas types cover the above types of gases, choosing a composite gas detector may achieve twice the result with half the effort.
