Phase Equilibrium Prediction Using Proximity Ratio Index
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Solution Overview
Problem
Current methods for correlating and predicting phase equilibrium data are hindered by imprecise measurements and experimental errors, leading to inefficient design and operation of component separators and refineries due to unknown phase equilibrium relationships.
Innovation Solution
A method involving the calculation of an index X of proximity ratio to critical points and infinite dilution pressure gradients Y1 and Y2, which are correlated to determine accurate infinite dilution activity coefficients or binary parameters A and B, allowing for precise prediction of phase equilibrium data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase equilibrium data is measured experimentally for each system, then the phase equilibrium relationship can be determined, but measurement errors and experimental uncertainties reduce the prediction accuracy
Solution Approach 1:
The patent introduces an index of proximity ratio to critical points as an intermediary parameter that correlates with infinite dilution activity coefficients. This mediator enables prediction of phase equilibrium relationships without direct experimental measurement for each system, thereby eliminating measurement errors while maintaining reliability through thermodynamic consistency.
Solution Approach 2:
The method utilizes readily available critical point data and vapor pressure information to self-determine phase equilibrium relationships through calculated indices and correlations. This self-service approach eliminates the need for separate experimental measurements for each system while providing reliable predictions based on fundamental thermodynamic properties.
2Reliability
If safety factors are increased in apparatus design to account for unknown phase equilibrium relationships, then product properties and productivity are secured, but economic efficiency decreases
Solution Approach 1:
The patent replaces the mechanical approach of adding safety factors to apparatus design with a theoretical calculation method based on thermodynamic correlations. By substituting empirical safety margins with scientifically derived phase equilibrium predictions, the method achieves both reliability for product properties and economic efficiency by avoiding oversized equipment.
3Ease of manufacture
If the number of contact stages or packed column height is determined using imprecise phase equilibrium data, then the distillation column can be designed, but the design precision and separation efficiency are reduced
Solution Approach 1:
The patent transforms the design approach by changing from using imprecise experimental phase equilibrium data to using precisely calculated parameters including the index of proximity ratio, infinite dilution activity coefficients, and thermodynamically consistent correlations. This parameter transformation enables accurate determination of contact stages and column height while maintaining ease of design through systematic calculation procedures.
Data Source
AI summary
A method for precisely predicting phase equilibrium from existing phase equilibrium data on the basis of a wide range of phase equilibrium data including binary vapor-liquid equilibrium data; a method or apparatus for designing or controlling a component separator or a refiner using the prediction method; and a program for designing this design or control apparatus. Binary phase equilibrium measurement data is used to calculate an index of proximity ratio to critical points and infinite dilution pressure gradients. The obtained index is correlated with the infinite dilution pressure gradients to newly calculate infinite dilution activity coefficients from the respective index to infinite dilution pressure gradients correlations. The obtained infinite dilution activity coefficients values are used to predict phase equilibrium. Thus, the obtained values are used to design or control a component separator or a refiner, such as a distillation column.