Liquefied Petroleum Gas (LPG)

Highly flammable mixture of hydrocarbon gases used as a fuel for heating appliances and vehicles is known as liquefied petroleum gas. In the efforts going to protect ozone layer, LPG replaces chlorofluorocarbons and it is used as aerosol propellant and refrigerant.  LPG includes mixes that are primarily propane, primarily butane and most common mixes include both propane and butane. In winter more propane is used and in summer more butane is used. To detect the leak of gas, a powerful odorant ethanethiol is added to it.  To synthesize LPG, petroleum or wet natural gas has to be refined.  It is generally obtained from fossil fuel sources. LPG is normally provided in pressurized steel cylinders as it easily evaporates at normal pressure and temperature. The gas is highly flammable also.

Characteristics of LPG

The specific calorific value of LPG is 46.1 MJ/kg. Its energy density per volume unit is 26 MJ/I. The gas evaporates easily at normal temperature and pressure. The volume of vaporized gas and liquefied gas is typically around 250:1. The pressure at which LPG becomes liquid is known as vapour pressure. The gas allows efficient cooking. It is heavier than air. The gas is odourless and colorless. LPG can be stored in a number of ways.

Uses

LPG can provide an alternative to electricity and heating oil. It is mostly used in places where there are no facilities for piped natural gas. It is a power source for combined heat and power technologies. LPG is used as a fuel in internal combustion engines where the gas is known as auto gas or auto propane. It is used in spark ignition engines as an alternative for petrol. With the help of gas absorption refrigerator, LPG provides off-the-grid refrigeration. LPG is the most commonly used cooking fuel all over the world.

Comparison of LPG with natural gas

 The calorific value of LPG is 94 MJ/m³. This is greater than that of natural gas (38 MJ/m³). This proves that LPG cannot be replaced by natural gas. When LPG is combined with air a synthetic natural gas is formed and this can be replaced easily. Synthetic natural Gas is used as an emergency backup system for many public and industrial uses in case of unavailability of natural gas.LPG that is used commercially is derived from fossil fuels. When LPG is burned it releases CO₂.  Carbon dioxide is a greenhouse gas and it leads to global warming.

Questions:

• What are the characteristics of LPG?
• What are the uses of LPG?