Journal of Applied Electrochemistry

, Volume 24, Issue 12, pp 1206–1212

Electrolytic process optimization by simultaneous-modular flowsheeting

  • R. D. La Roche
  • M. A. Stadtherr
  • R. C. Alkire
Papers

DOI: 10.1007/BF00249883

Cite this article as:
La Roche, R.D., Stadtherr, M.A. & Alkire, R.C. J Appl Electrochem (1994) 24: 1206. doi:10.1007/BF00249883

Abstract

A procedure is described for computer-assisted optimization of an electrolytic process flowsheet. Material, energy, and economic balances for all process units were incorporated in a nonlinear optimization routine for predicting the minimum selling price based on a discounted cash flow rate of return on investment. The optimization utilized a simultaneous-modular approach which was incorporated into the public version of the Aspen flowsheeting package, and used an infeasible path convergence method based on successive quadratic programming procedures. Electrolyte vapour-liquid equilibrium data were estimated by the ‘non-random two-liquid’ model. The Lagrangian multipliers of the constraint equations were used to determine the sensitivity of the optimum to key process variables. The method was illustrated by evaluation of two process flowsheets for electrosynthesis of methyl ethyl ketone (MEK) from 1-butene based on pilot-plant performance reported in the patent literature.

List of symbols

Ac

cell cost factor ($ cell−1)

AH

heat exchanger cost factor ($ m−2)

Ap

pump cost factor ($ sl−1)

AR

rectifier cost factor ($ kVA−1)

AT

tank cost factor ($l−0.5)

Acm

cell maintenance factor ($ A−1 y−1)

Acl

cell labour ($ cell−1 y−1)

Acw

cooling water cost ($ m−3)

Ae

electricity cost ($ kWh)

Am

membrane cost ($ cell−1 y−1)

Aom

other maintenance factor, fraction of plant capital less cell cost

Cp

cooling water heat capacity (kJ kg−1 °C−1)

H

operating hours per year

IC

current to each cell (A)

ITOT

total current to all cells (A)

LA

Lang factor for auxiliaries

LC

Lang factor for cells

LR

Lang factor for rectifiers

N

number of cells in plant

Q

heat removal load (kJ h−1)

R

production rate (kgh−1)

ΔTcw

cooling water temperature rise (°C)

ΔTLM

cooler log mean temperature difference (°C)

U

heat transfer coefficient for cooler (kW m−2 °C−1)

vc

electrolyte flow to each cell (l∝-1)

vC

cell voltage (V)

εR

rectifier efficiency

ϱ

cooling water density (kg m−3)

ϕT

surge tank residence time (s)

Copyright information

© Chapman & Hall 1994

Authors and Affiliations

  • R. D. La Roche
    • 1
  • M. A. Stadtherr
    • 1
  • R. C. Alkire
    • 1
  1. 1.Department of Chemical EngineeringUniversity of IllinoisUrbanaUSA
  2. 2.Cray ResearchEaganUSA

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