Liquefied petroleum gas basic knowledge
First, the source of liquefied petroleum gas, composition
1, the source of liquefied petroleum gas Liquefied petroleum gas is in the process of oil and gas exploration and refining, obtained as a by-product of propane, butane as the main component of hydrocarbons. At room temperature and pressure for the gas, only under pressure or cooling conditions, it becomes liquid, it is called liquefied petroleum gas. At room temperature, ethane, ethylene, propane, butylene, butane and the like in liquefied petroleum gas are all colorless and odorless gases that are lighter than water and insoluble in water. The pungent odor in liquefied petroleum gas is produced by components such as mercaptans and ethers, which are deliberately added during transportation and storage, to facilitate the user's detection of liquefied petroleum gas leakage. LPG, English Liquefied Petroleum Gas, abbreviated LPG.
2, the main components of liquefied petroleum gas composition: propane (C3H8), butane (C4H10) a small amount of ingredients: methane, ethane, propylene, butylene. Raffinate: liquefied petroleum gas cylinders always have a trace amount of liquid used up, the part of the liquid known as raffinate, the main components of pentane and pentane hydrocarbons and above. Liquefied petroleum gas national standard raffinate content of not more than 3%.
Production of liquefied petroleum gas (LPG): Produced mainly from the refinery in the pyrolysis of refined petroleum. Liquefied petroleum gas (LPG) can be obtained during the processing of atmospheric and vacuum distillation, thermal cracking, catalytic cracking, platinum reforming and delayed coking in petroleum refineries and petrochemical plants. Generally speaking, refining 1 ton of crude oil can produce 3% 5% liquefied petroleum gas; liquefied petroleum gas can also be recovered from natural gas. The crude oil and moisture mixture coming out of the oil field is separated by a gas-liquid separator. The natural gas from the upper part is sent to a gas storage tank and is subjected to re-fractionation under pressure (16 kg / cm2) and absorbed by a diesel spray. Natural gas (dry gas) Sent from the tower, the rich gas absorption of liquefied gas through the fractionation tower, at a pressure of 16kg / cm2 condensed into a liquid to form liquefied petroleum gas.
LPG production there are three main ways.
1. Production from oil and gas fields During the exploitation of oil fields, when the hydrocarbon gas or gas field in the crude oil is carried, the other hydrocarbons carried in the natural gas are initially separated and treated and then sent to the gas separation Factory processing, and finally were propane, butane. Under certain pressure or frozen to a certain temperature propane, butane were liquefied separately, and sub-installed in different tanks. Manufacturers can sell propane, butane, respectively, according to user requirements, the propane, butane, according to a certain percentage, deployed to meet the quality standards of the LPG resold.
2, LPG production from refineries is a by-product of the oil refining process. Normally, crude oil is at atmospheric and vacuum distillation, thermal cracking (this process has been basically eliminated in our country), catalytic cracking, catalytic reforming, hydrocracking and delayed coking and other processing plant process will produce hydrocarbon gas off, these After the gas is absorbed and stabilized, dry gas (lean gas) and rich gas are separated under a certain pressure. The main components of dry gas methane and non-hydrocarbon gases, as well as a small amount of ethane and ethylene. Such gas is usually sent directly to the gas tank and then sent to the refiner's furnace for fuel. The main components of rich gas are propane, propylene, butane, butylenes, small amounts of pentenes and Non-hydrocarbon compounds, this type of gas under pressure to become mainly composed of propane, propylene, butane, butene composition LPG. The LPG of China's refinery is mainly obtained from the catalytic cracking unit.
3. Production from Ethylene Plants LPG components are also produced during the cracking of light oil or light hydrocarbons to produce ethylene. The ethylene plant's production goals determine the poor quality of LPG produced by such plants, Carbon four high components. If the refinery and ethylene plant are unitary, it is usually possible to allocate the two LPGs with different sources to obtain LPG that meets national standards.