K-Value Formula:
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Definition: The K-value is defined as the ratio of vapor-phase mole fraction to the liquid-phase mole fraction of a component in a mixture.
Purpose: It's crucial in vapor-liquid equilibrium calculations for designing and analyzing distillation columns and other separation processes.
The calculator uses the formula:
Where:
Explanation: The activity coefficient accounts for non-ideal behavior, while the ratio of pressures determines the equilibrium distribution.
Details: Accurate K-values are essential for designing efficient separation processes, predicting phase behavior, and optimizing chemical processes.
Tips: Enter the activity coefficient (typically between 0 and 10), saturated pressure in Pascals, and total system pressure in Pascals. All values must be > 0.
Q1: What is a typical range for K-values?
A: K-values typically range from 0.001 to 1000, depending on the component and system conditions.
Q2: When is the activity coefficient equal to 1?
A: The activity coefficient is 1 for ideal solutions where components behave similarly to their pure states.
Q3: How does temperature affect K-values?
A: Temperature primarily affects the saturated pressure term - higher temperatures generally increase K-values.
Q4: What's the difference between Raoult's Law and Modified Raoult's Law?
A: Modified Raoult's Law includes the activity coefficient to account for non-ideal behavior, while standard Raoult's Law assumes ideal behavior.
Q5: How do I find activity coefficients?
A: Activity coefficients can be determined experimentally or calculated using thermodynamic models like UNIFAC or NRTL.