Journal
COMPUTERS & CHEMICAL ENGINEERING
Volume 36, Issue -, Pages 99-118Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.compchemeng.2011.07.009
Keywords
Phase equilibrium; Phase stability; Helmholtz free energy; Global optimisation; Equations of state; Statistical associating fluid theory (SAFT)
Funding
- Engineering and Physical Sciences Research Council (EPSRC) of the UK
- EPSRC [GR/T17595, GR/N35991, GR/R09497, EP/E016340]
- Joint Research Equipment Initiative (JREI) [GR/M94427]
- Royal Society-Wolfson Foundation
- EPSRC [EP/E016340/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/E016340/1] Funding Source: researchfish
Ask authors/readers for more resources
The HELD (Helmholtz free Energy Lagrangian Dual) algorithm is proposed to solve the isothermal, isobaric phase equilibrium problem (P, T flash). The flash is posed as a minimisation of the Helmholtz free energy in the volume-composition space, reformulated through duality theory. The proposed solution strategy consists of: an initialisation stage, containing a stability test; a phase identification stage, in which linear and nonconvex optimisation problems are solved alternatively; and an acceleration and convergence stage. The stability test is solved with a tunneling algorithm and the nonconvex part of the second stage with a multistart approach. Examples are presented for three equations of state, SRK, SAFT-HS and SAFT-VR. Non-ideal mixtures of up to fifteen components are examined; they exhibit features such as azeotropy, liquid-liquid, and liquid-liquid-liquid equilibria. The HELD algorithm is found to be reliable over a variety of challenging phase behaviour, converging to the best known solution in all of the calculations undertaken. (C) 2011 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available