# How to Calculate Final Pressure in a CO2-Saturated Sealed Vessel?

• nbcromp1
In summary, The sealed vessel contains saturated CO2 at room temperature. The partial pressure of the CO2 in equilibrium with water is 25 C. The vapor pressure of water at 130 C is 2.687 bar.
nbcromp1
I have a sealed vessel, it is 200 ml, it contains 25 ml of water which is then saturated with CO2 (bubbled through at 0.3 l/min unitil pH drops, ~ 1 h) at rt. The vessel is then heated to 130 °C. I wish to calculate the final pressure of the system.

Thus far I have calculated the volume of CO2 in the water using NIST solubility values.
I believe the total pressure of the system to be P= PsatW + Po + Pn + Pco2.
The saturation pressure of water is calculated using the Antonine equation
Then the partial pressures of oxygen, nitrogen and CO2 are calculated using the ideal gas eq.

However, I am not sure whether I can apply the ideal gas equation to the dissolved CO2.
Additionally I am not including Henry's Law to account for air dissolved in water as I am assuming the solution is saturated(or near enough) with CO2.

Is there another way of doing this? Does anyone know how to account for the dissolved CO2?

The water has been saturated with CO2 in water initially at room temperature, and you know the partial pressure of the CO2 in equilibrium with the water at 25 C? Then you heat it up to 130 C in a 200 ml container with air and CO2 initially in the head space?

I have a literature based value of what the partial pressure of the CO2 in equilibrium with water will be at 25C. Your second statement is also correct. I essentially want to ensure I am not going to break the 4 bar pressure limit on the vessel. I believe the CO2 should have an almost negligible effect, however I need to write a risk assessment.

nbcromp1 said:

I have a literature based value of what the partial pressure of the CO2 in equilibrium with water will be at 25C. Your second statement is also correct. I essentially want to ensure I am not going to break the 4 bar pressure limit on the vessel. I believe the CO2 should have an almost negligible effect, however I need to write a risk assessment.
To be conservative, assume all the CO2 comes out of solution at 130 C. What is the vapor pressure of water at 130 C?

Ok so I think what I have initially done is right then, calculated the vapour pressure of water using the Antonine to be 2.687 bar at 130 °C, then added the pressure of the total number of moles of gas, not accounting for final liquid volume and dissolution of gas in water. This should provide a safe estimate.

Chestermiller

## 1. What is pressure in a sealed vessel?

Pressure in a sealed vessel refers to the force exerted by the molecules of a gas or liquid inside a sealed container. It is measured in units of force per unit area, such as pounds per square inch (psi) or pascals (Pa).

## 2. How does pressure in a sealed vessel affect the contents inside?

The pressure in a sealed vessel affects the behavior of the gas or liquid inside. As the pressure increases, the molecules are pushed closer together, causing the volume to decrease and the temperature to rise. In contrast, decreasing pressure causes the volume to increase and the temperature to decrease.

## 3. What factors affect the pressure in a sealed vessel?

The pressure in a sealed vessel is affected by the amount of gas or liquid present, the temperature, and the volume of the container. Additionally, the type of gas or liquid, as well as external factors like altitude and atmospheric pressure, can also impact the pressure inside a sealed vessel.

## 4. How is pressure in a sealed vessel measured?

Pressure in a sealed vessel can be measured using a variety of instruments, such as a manometer, barometer, or pressure gauge. These devices typically measure the force exerted by the gas or liquid in the container and convert it to a readable unit of pressure.

## 5. What happens if the pressure in a sealed vessel becomes too high?

If the pressure in a sealed vessel becomes too high, the container may burst or explode. This can be dangerous and should be avoided by properly regulating the pressure inside the vessel. Additionally, high pressure can also cause changes in the physical properties of the gas or liquid, such as changes in temperature or phase.

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