Humidity and Partial Pressure

A clear explanation of the basic knowledge necessary to understand distillation, distillation towers, and distillation equipment!

Kansai Chemical will explain "Humidity and Partial Pressure." The atmosphere is a mixture of air and water, and the ratio of this mixture is humidity. Just above a boiling pot, there is no air, only 100% water vapor. Therefore, the pressure of that water vapor is equal to atmospheric pressure. Most liquids have a vapor pressure determined by temperature, and the vapor pressure of water at 30°C (saturated vapor pressure) is 42 hPa. If the atmospheric pressure on Earth were 42 hPa, water would boil at 30°C. However, the atmospheric pressure at ground level is considered to be an average of 1,013 hPa (neither high pressure nor low pressure). If the water in the pot is at 30°C, then the water vapor just above the surface of the water is 42 hPa, and the air pressure is (1,013 - 42) = 971 hPa. When several components are mixed, the total pressure is called the total pressure, and the pressure exerted by each component (air, water) is called the partial pressure. And this is known as "the total pressure is equal to the sum of the partial pressures (Dalton's Law of Partial Pressures)." *For more details, please refer to the PDF document or feel free to contact us.

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