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

Authors

  • Hisham S. Bamufleh
    • Chemical and Materials Engineering Department, Faculty of EngineeringKing Abdulaziz University
  • José María Ponce-Ortega
    • Chemical Engineering DepartmentUniversidad Michoacana de San Nicolás de Hidalgo
    • Chemical and Materials Engineering Department, Faculty of EngineeringKing Abdulaziz University
    • Chemical Engineering DepartmentTexas A&M University
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 power Energy integration Process integration Greenhouse gas emissions Optimization

List of symbols

A

Constant for the turbine efficiency relationship

a 0

Constant for the turbine efficiency

a 1

Constant for the turbine efficiency

a 2

Constant for the turbine efficiency

a 3

Constant for the turbine efficiency

a e

Electrical power price

a f

Unit fuel cost for fuel f

A s

Constant for the saturation temperature correlation

B

Constant for the turbine efficiency relationship

B s

Constant for the saturation temperature correlation

C boiler

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

C Turbine

Cost for the turbine

fc P,v

Flowrate times heat capacity for cold process stream v

FC P,u

Flowrate times heat capacity for hot process stream u

F p

Flexibility factor for the increase in pressure in the boiler

GHG

Greenhouse gas emissions

ghge f

Unit greenhouse gas emissions for fuel f

h

Enthalpy

h 1

Enthalpy for the steam at the turbine inlet

ha2

Actual enthalpy for the steam at the outlet from the turbine

h f

Saturated fluid enthalpy

his2

Outlet isentropic enthalpy

H Y

Hours per year that operates the plant

JOB

Total generated jobs

jobs f

Unit jobs for fuel f

k F

Factor used to annualize the capital costs

m

Steam flowrate

M max

Maximum flowrate in the turbine

N C

Total number of cold process streams

N H

Total number of hot process streams

N p

Factor for accounting for the operating pressure

N T

Factor accounting for the superheat temperature

P

Pressure

P e

Electric power price

P t

Turbine shaft power output

Pg1

Gauge pressure of the boiler

Q b

Heat load required in the boiler

Q f

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

Q process

Heating requirement for the process streams

s

Entropy

T

Temperature

T 1

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

T sh

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

Δh is

Isentropic enthalpy difference in the turbine

η f

Efficiency in the boiler for the fuel f

η g

Generator efficiency

η is

Isentropic efficiency for the turbine

η is

Maximum efficiency in the turbine

η turbine

Turbine efficiency

Conditions

1

Low pressure

2

High pressure

Copyright information

© Springer-Verlag 2012