The Dynamics of LPG in Cooking Cylinders

Summary

This narrative explores the thermodynamic principles governing the behaviour of liquefied petroleum gas (LPG) in cooking gas cylinders. It details the process of gas expansion when the valve opens, the subsequent phase change as liquid LPG evaporates to restore equilibrium, and the self-regulating mechanism that maintains pressure balance. The interplay of pressure, temperature, and latent heat is highlighted, ensuring efficient cooking gas delivery.

Hashtags

#cooking #LPG #kitchen #gas #thermodynamics

Script
In a kitchen, a cooking gas cylinder stores liquefied petroleum gas-LPG, primarily composed of propane-C₃H₈ and butane-C₄H₁₀, under high pressure.

When the valve opens, pressure drops, causing the liquid to vaporize into gas. This gaseous LPG flows to the burner, mixes with air, and combusts, releasing heat for cooking.

Thermodynamically, the gas performs expansion work, W=−PextΔV, as it exits the cylinder. When the valve is closed, the system is no longer in equilibrium, pressure drops due to release of some gases.

To restore equilibrium, more of the liquid LPG evaporates, a phase change, absorbing latent heat from the surroundings. This evaporation increases the vapor pressure inside the cylinder until it matches the external pressure again, re-establishing equilibrium.

This self-regulating mechanism ensures that liquid LPG remains inside the cylinder as long as enough remains and the temperature stays sufficient.

Видео The Dynamics of LPG in Cooking Cylinders канала VARIENTICA