Does dalton's law hold for liquids?

[jimRH9]

hullo, i was wondering; does dalton's law ( pressure*mole fraction = partial pressure) hold for liquids?

I'm doing a design project in uni on natural gas production. I'm trying to do a mass balance for the "hydrocarbon dewpoint contol" aspect of the "plant" which is oil absorption. I'm trying to find out how much hydrocarbon components (methane, ethane, propane, butane and pentane) the oil will absorb. I read in a book that it ereaches equilibrium when partial pressure of the liquid = partial pressure of the gas, so I tried to work out what the partial pressure of the gas will be (by the antoine equation, since both liquid and gas phases exist partial pressure = vapour pressure... right?) so I'm trying to work out all the mole fractions of the liquid phase (by deviding this by the pressure in the tower) but it gives me stupid answers - the oil should adsorb more of the heavier components than the lighter ones.

I thought it might have something to do with henry's law, I thought i might be able to get a table of henry's law constants for methane, ethane, propane, butane and pentane in some non polar solvent similar to my oil, but I can't seem to find any such table.

...as you can probably tell, I'm a little confused! I'll see if I can attach my half-baked mass balance for a bit of clarity:

 

[Navin A S]

G (gas phase) : (Fg*Pvap) + (Fg*Pg) = Fg*Ptotal L (liquid phase) : (Fl*Ptotal) = Fl*Pl Where: Fg = molar flow rate of the gas Pvap = vapour pressure of the gas Pg = pressure of the gas Fl = molar flow rate of the liquid Pl = pressure of the liquid Ptotal = total pressure So, does dalton's law hold for liquids? (i.e. Pl*Xl = Ppartial) Yes, Dalton's law does hold for liquids. In fact, it is more accurately known as Dalton's Law of Partial Pressures and states that the sum of the partial pressures of all components in a mixture is equal to the total pressure. This law applies to both gases and liquids.

 

[oswaler]

Dalton's law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas. This law does not hold for liquids because liquids do not have the ability to exist in a gaseous state. Instead, liquids have their own unique properties and behaviors that are governed by different laws and principles.

In your design project for natural gas production, you are looking at the hydrocarbon dewpoint control aspect which involves oil absorption. This process involves the equilibrium between the liquid and gas phases, where the partial pressure of the liquid is equal to the partial pressure of the gas. This is known as Henry's law, which states that the amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid.

To determine the partial pressure of the gas, you are using the Antoine equation which relates the vapor pressure of a substance to its temperature. However, this equation is typically used for pure substances and may not accurately represent the behavior of a mixture of gases. Additionally, the mole fractions of the liquid phase are not solely determined by the pressure in the tower, but also by the composition of the liquid itself.

To accurately determine the mole fractions of the liquid phase, you may need to use experimental data or thermodynamic models specific to your system. These models can take into account factors such as non-ideal behavior and interactions between the different components in the liquid.

In summary, Dalton's law does not hold for liquids and instead, Henry's law is the relevant principle for your project. It is important to use appropriate models and data to accurately determine the behavior of your system.