Liquid Co2 measuremnt in CSD factory

How can we determine the current amount of liquid CO2 in the tank in the carbonated beverage industry? Please show me the calculation method. BY Pressure and temeperature of method or else

To determine the current amount of liquid CO₂ in a tank, commonly used in the carbonated beverage industry, you typically need to rely on either:

1. Weight Measurement Method
2. Pressure and Temperature Method

1. Weight Measurement Method

This is the most direct and accurate method for determining the amount of liquid CO₂ in a tank.

Steps:

• Weigh the Tank: Weigh the tank when it's full and when it's empty. The difference between the full weight and the empty weight gives the total weight of the liquid CO₂.
• Determine Current Weight: Weigh the tank to determine its current weight.
• Calculate Remaining CO₂: Subtract the empty weight of the tank from the current weight to find out how much CO₂ is left.

Formula:

Current CO2 in tank=Current tank weight−Empty tank weight\text{Current CO}_2 \text{ in tank} = \text{Current tank weight} - \text{Empty tank weight}Current CO2​ in tank=Current tank weight−Empty tank weight

2. Pressure and Temperature Method

This method involves using the pressure and temperature of the CO₂ in the tank to estimate the amount of liquid CO₂. This method is less accurate than the weight measurement method, but it can still provide useful information.

Key Concepts:

• CO₂ Vapor-Liquid Equilibrium: In a tank containing both liquid and vapor CO₂, there exists a relationship between the pressure and temperature. At a given temperature, the pressure in the tank corresponds to a specific equilibrium between the liquid and vapor phases.
• CO₂ Pressure-Temperature Chart: These charts show the equilibrium pressure of CO₂ at different temperatures. By measuring the tank's pressure and temperature, you can estimate the amount of liquid CO₂.

Steps:

• Measure Pressure and Temperature: Use sensors to accurately measure the pressure and temperature inside the CO₂ tank.
• Consult CO₂ Pressure-Temperature Chart: Refer to a CO₂ pressure-temperature chart to determine the saturation pressure at the given temperature. If the tank pressure matches the saturation pressure, there is likely still liquid CO₂ in the tank. If the pressure is below the saturation pressure, most of the CO₂ might have evaporated, leaving only gas.
• Estimate Liquid CO₂: Use the pressure-temperature data to estimate the percentage of liquid CO₂ remaining. For accurate determination, more advanced models or software tools might be needed, as this method involves assumptions about the remaining gas and liquid volumes.

Example Calculation:

Assume the following data for a CO₂ tank:

• Temperature: 20°C
• Pressure: 57 bar (825 psi)

From a CO₂ pressure-temperature chart:

• The saturation pressure at 20°C is about 57 bar. This suggests that the tank is still in equilibrium with liquid CO₂ present.

Considerations:

• This method does not directly give the quantity of liquid CO₂ but rather indicates whether liquid CO₂ is still present.
• To estimate the volume or mass of CO₂, you would need additional data or models that account for the specific tank dimensions and initial fill.

Conclusion:

• Weight Measurement is the most straightforward and accurate method.
• Pressure and Temperature is useful for understanding the state of the CO₂ in the tank but requires additional modeling or charts to estimate quantity.