Question

The main constituent of LPG is:

• A. methane
• B. ethane
• C. propane
• D. butane

Answer 1

Answer:

D. butane

Liquefied Petroleum Gas (LPG) Explained

• Composition of LPG

  • LPG is a highly flammable mixture of hydrocarbon gases, primarily used as a fuel for heating, cooking, and in vehicles.
  • The main constituents of LPG are butane and propane. The exact proportion varies based on geographical region and seasonal demand.
  • In many domestic applications, especially in countries like India, butane (including n-butane and iso-butane) is often the predominant component.

• Key Properties and Benefits

  • LPG is stored under pressure in its liquid state and converts into gas when the pressure is released. This allows a significant amount of energy to be stored in a compact form.
  • It is recognized as a cleaner-burning fuel compared to traditional fossil fuels like coal, contributing to lower greenhouse gas emissions.
  • LPG possesses a high calorific value, meaning it releases a large amount of heat energy per unit mass, making it an efficient fuel source.

• Safety Feature: Odorant Addition

  • Pure LPG is inherently odorless, which makes leaks undetectable by smell alone.
  • To ensure safety and facilitate the detection of leaks, a strong-smelling chemical called ethyl mercaptan (also known as ethanethiol) is intentionally added to LPG.
  • Ethyl mercaptan has a distinct, unpleasant odor, often described as rotten cabbage or sulfur, serving as an important warning agent for gas leaks.

• Butane vs. Propane in Competitive Exams

  • Butane: It has a relatively higher boiling point (around -0.5 °C or 31 °F) and generally provides more energy per unit volume than propane. It is commonly preferred for indoor use and in regions with warmer climates.
  • Propane: Characterized by a much lower boiling point (approximately -42 °C or -43.6 °F). This property allows propane to vaporize effectively even in very cold temperatures, making it ideal for outdoor applications and colder geographical areas.
  • The blend ratio of butane and propane in commercial LPG is often adjusted to optimize performance based on the prevailing climatic conditions of the region.

• Storage and Applications

  • LPG is typically stored in specially designed steel cylinders or tanks, ranging from small domestic bottles to large industrial storage vessels.
  • Beyond its primary use as a fuel, LPG also finds applications as a refrigerant and as a propellant in aerosols.