Influence of electric heating on pressure increase in the liquefied petroleum gas storage tank

Published on:

2022-11-11 10:05

Liquefied petroleum gas is a mixture of hydrocarbons consisting of two elements, carbon and hydrogen Chemically organic compounds formed by carbon and hydrogen are collectively called hydrocarbons. Relatively high pressures are required to liquefy methane, ethane and ethylene with carbon atoms of less than three. More molecular hydrocarbons with more than four carbon atoms are in a liquid state at room temperature, so under normal conditions they are not components of liquefied petroleum gas. The main components of liquefied petroleum gas are hydrocarbons containing three carbon atoms and four carbon atoms, which in industry is also called carbon three and carbon four.

The saturated vapor pressure of a mixture of liquefied hydrocarbon gases is the vapor pressure when the gas-liquid phase of the mixture is in equilibrium at a certain temperature. That is, when the evaporation rate of the vapor molecules is equal to the condensation rate, the pressure and temperature are different, and the saturated vapor pressure is different The higher the temperature, the higher the saturated vapor pressure of each component. The temperature, the components are different, the saturated steam pressure is different, and the carbon vapor saturated pressure of compounds with shorter chains than those with longer carbon chains. Since the liquefied gas is a mixture, not a pure substance, the pressure in the cylinder depends on the mixture.

Taking as an example the catalytic liquefied petroleum gas of the refinery, its content is about 63.3% propylene and 36.7% butene. It was found that the pressure of saturated propylene vapor is 1.32 MPa at 30 ° C. and the pressure of saturated butene vapor is 0.35 MPa. After calculation, its saturated steam pressure is 0.82 MPa, which is very close to the working pressure of 0.8 MPa in our normal production. Therefore, we only need to maintain the storage tank temperature at 30 °C in winter to match the performance. Needs.

The application principle of the electric heating cable is as follows: when the medium is stored or flows in the container tank of the pipeline, it must give heat to the outside. The temperature required for the environment meets the technological requirements. After repeated negotiations, we put a powerful 50 W/meter electric heating belt at the plant.

The series of constant power parallel electric heating tapes has a constant calorific value per unit length. The longer the electric heating belt is used, the greater the total output power, and the maximum usage length of one circuit is longer; it is mainly used for various high-temperature piping, instrumentation, and tanks. hull equipment insulation, Maintaining temperature and heating high, can be used in explosive gas situations in the first and second premises of the plant.

Latest News

Please search according to your needs.