Clean Technologies and Environmental Policy

, Volume 15, Issue 1, pp 185–197

Multi-objective optimization of process cogeneration systems with economic, environmental, and social tradeoffs

  • Hisham S. Bamufleh
  • José María Ponce-Ortega
  • Mahmoud M. El-Halwagi
Original Paper

DOI: 10.1007/s10098-012-0497-y

Cite this article as:
Bamufleh, H.S., Ponce-Ortega, J.M. & El-Halwagi, M.M. Clean Techn Environ Policy (2013) 15: 185. doi:10.1007/s10098-012-0497-y

Abstract

Process cogeneration is an effective strategy for exploiting the positive aspects of combined heat and power in the process industry. Traditionally, decisions for process cogeneration have been based mostly on economic criteria. With the growing interest in sustainability issues, there is need to consider economic, environmental, and social aspects of cogeneration. The objective of this article is to develop an optimization framework for the design of process cogeneration systems with economic, environmental, and social aspects. Process integration is used as the coordinating framework for the optimization formulation. First, heat integration is carried out to identify the heating utility requirements. Then, a multi-header steam system is designed and optimized for inlet steam characteristics and their impact on power, fixed and operating costs, greenhouse gas emissions, and jobs. A genetic algorithm is developed to solve the optimization problem. Multi-objective tradeoffs between the economic, environmental, and social aspects are studied through Pareto tradeoffs. A case study is solved to illustrate the applicability of the proposed procedure.

Keywords

Combined heat and powerEnergy integrationProcess integrationGreenhouse gas emissionsOptimization

List of symbols

A

Constant for the turbine efficiency relationship

a0

Constant for the turbine efficiency

a1

Constant for the turbine efficiency

a2

Constant for the turbine efficiency

a3

Constant for the turbine efficiency

ae

Electrical power price

af

Unit fuel cost for fuel f

As

Constant for the saturation temperature correlation

B

Constant for the turbine efficiency relationship

Bs

Constant for the saturation temperature correlation

Cboiler

Cost for the boiler

Costa

Combustion air fan power cost

Costb

Sewer charges for boiler blowdown

Costd

Ash disposal cost

Coste

Environmental emissions control cost

CostBFW

Boiler feed water treatment cost

Costfuel

Fuel cost

Costg

Generation cost

Costm

Maintenance materials and labor cost

Costp

Feed water pumping power cost

Costw

Raw water supply cost

CTurbine

Cost for the turbine

fcP,v

Flowrate times heat capacity for cold process stream v

FCP,u

Flowrate times heat capacity for hot process stream u

Fp

Flexibility factor for the increase in pressure in the boiler

GHG

Greenhouse gas emissions

ghgef

Unit greenhouse gas emissions for fuel f

h

Enthalpy

h1

Enthalpy for the steam at the turbine inlet

ha2

Actual enthalpy for the steam at the outlet from the turbine

hf

Saturated fluid enthalpy

his2

Outlet isentropic enthalpy

HY

Hours per year that operates the plant

JOB

Total generated jobs

jobsf

Unit jobs for fuel f

kF

Factor used to annualize the capital costs

m

Steam flowrate

Mmax

Maximum flowrate in the turbine

NC

Total number of cold process streams

NH

Total number of hot process streams

Np

Factor for accounting for the operating pressure

NT

Factor accounting for the superheat temperature

P

Pressure

Pe

Electric power price

Pt

Turbine shaft power output

Pg1

Gauge pressure of the boiler

Qb

Heat load required in the boiler

Qf

Heat load for the combustion of fuel f supplied to the boiler

Qprocess

Heating requirement for the process streams

s

Entropy

T

Temperature

T1

Inlet temperature to the turbine

TAC

Total annual cost

Tsat

Saturation temperature

Tsat1

Saturation temperate for the steam inlet to the turbine

Tsat2

Saturation temperate for the steam at high pressure

Tsh

Superheat temperature

\( t_{v}^{\text{s}} \)

Temperature supplied for cold process stream v

\( T_{u}^{\text{s}} \)

Temperature supplied for hot process stream u

\( t_{v}^{\text{t}} \)

Target temperature for cold process stream v

\( T_{u}^{\text{t}} \)

Target temperature for hot process stream u

u

Hot process streams

v

Cold process streams

W

Work

Greek symbols

Δhis

Isentropic enthalpy difference in the turbine

ηf

Efficiency in the boiler for the fuel f

ηg

Generator efficiency

ηis

Isentropic efficiency for the turbine

ηis

Maximum efficiency in the turbine

ηturbine

Turbine efficiency

Conditions

1

Low pressure

2

High pressure

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Hisham S. Bamufleh
    • 1
  • José María Ponce-Ortega
    • 2
  • Mahmoud M. El-Halwagi
    • 1
    • 3
  1. 1.Chemical and Materials Engineering Department, Faculty of EngineeringKing Abdulaziz UniversityJeddahSaudi Arabia
  2. 2.Chemical Engineering DepartmentUniversidad Michoacana de San Nicolás de HidalgoMoreliaMexico
  3. 3.Chemical Engineering DepartmentTexas A&M UniversityCollege StationUSA