TY - JOUR

T1 - Computing multi-species chemical equilibrium with an algorithm based on the reaction extents

AU - Paz-Garcia, Juan Manuel

AU - Johannesson, Björn

AU - Ottosen, Lisbeth M.

AU - Ribeiro, Alexandra B.

AU - Rodríguez-Maroto, José Miguel

PY - 2013

Y1 - 2013

N2 - A mathematical model for the solution of a set of chemical equilibrium equations in a multi-species and multiphase chemical system is described. The computer-aid solution of model is achieved by means of a Newton-Raphson method enhanced with a line-search scheme, which deals with the non-negative constrains. The residual function, representing the distance to the equilibrium, is defined from the chemical potential (or Gibbs energy) of the chemical system. Local minimums are potentially avoided by the prioritization of the aqueous reactions with respect to the heterogeneous reactions. The formation and release of gas bubbles is taken into account in the model, limiting the concentration of volatile aqueous species to a maximum value, given by the gas solubility constant.The reaction extents are used as state variables for the numerical method. As a result, the accepted solution satisfies the charge and mass balance equations and the model is fully compatible with general reactive transport models. © 2013 Elsevier Ltd.

AB - A mathematical model for the solution of a set of chemical equilibrium equations in a multi-species and multiphase chemical system is described. The computer-aid solution of model is achieved by means of a Newton-Raphson method enhanced with a line-search scheme, which deals with the non-negative constrains. The residual function, representing the distance to the equilibrium, is defined from the chemical potential (or Gibbs energy) of the chemical system. Local minimums are potentially avoided by the prioritization of the aqueous reactions with respect to the heterogeneous reactions. The formation and release of gas bubbles is taken into account in the model, limiting the concentration of volatile aqueous species to a maximum value, given by the gas solubility constant.The reaction extents are used as state variables for the numerical method. As a result, the accepted solution satisfies the charge and mass balance equations and the model is fully compatible with general reactive transport models. © 2013 Elsevier Ltd.

KW - Mathematical models

KW - Newton-Raphson method

U2 - 10.1016/j.compchemeng.2013.06.013

DO - 10.1016/j.compchemeng.2013.06.013

M3 - Journal article

SN - 0098-1354

VL - 58

SP - 135

EP - 143

JO - Computers & Chemical Engineering

JF - Computers & Chemical Engineering

ER -