השוואת שיטות

	UNIFAC	משוואת מצב פנג-רובינסון	ניתוח צבת
תחום	פיזיקה יישומית	פיזיקה יישומית	פיזיקה יישומית
משפחה	Process / pipeline	Process / pipeline	Process / pipeline
שנת המקור	1975	1976	1978
הוגה השיטה	Aage Fredenslund, Russell Jones, John Prausnitz	Ding-Yu Peng and David Bernard Robinson	Bodo Linnhoff, John Flower
סוג	Activity coefficient model; predictive liquid-phase property method	Equation of state; thermodynamic property correlation	Thermal design and optimization method
מקור מכונן	Fredenslund, A., Jones, R. L., & Prausnitz, J. M. (1975). Group-contribution estimation of activity coefficients in nonideal liquid mixtures. AIChE Journal, 21(6), 1086-1099.	Peng, D. Y., & Robinson, D. B. (1976). A new two-constant equation of state. Industrial & Engineering Chemistry Fundamentals, 15(1), 59-64.	Linnhoff, B., & Flower, J. R. (1978). Synthesis of heat exchanger networks: I. Systematic generation of energy optimal networks. AIChE Journal, 24(4), 633-642.
כינויים	UNIFAC predictive model, UNIQUAC functional-group contribution	PR-EOS, Peng-Robinson model	heat integration, pinch point method, process integration
קשורות	3	4	4
תקציר	UNIFAC (Universal Functional-group Activity Coefficient) is a predictive model for liquid-phase activity coefficients of multicomponent mixtures. Developed by Fredenslund, Jones, and Prausnitz in 1975, it decomposes molecules into functional groups and uses group interaction parameters to estimate non-ideal behavior. UNIFAC is revolutionary because it can predict phase equilibria for mixtures never experimentally measured, making it invaluable for process design and chemical engineering.	The Peng-Robinson equation of state is a cubic model that describes the thermodynamic properties of pure fluids and mixtures. Introduced by Ding-Yu Peng and David Bernard Robinson in 1976, it improves upon earlier models (van der Waals, Redlich-Kwong) by better predicting compressibility factors and phase equilibria, especially near the critical point. It is widely used in petroleum engineering, chemical process design, and natural gas calculations.	Pinch analysis is a systematic method for identifying the minimum energy requirements and optimal heat recovery opportunities in chemical processes. Developed by Bodo Linnhoff and John Flower in 1978, it graphically identifies the 'pinch point'—the most constrained part of the process where heating and cooling demands nearly balance. By targeting these bottlenecks, engineers can design energy-efficient heat exchanger networks and reduce operating costs dramatically.