RESOURCE CONSERVATION AND ALLOCATION VIA PROCESS INTEGRATION A Dissertation ...

200 Pages·2004·0.56 MB·English

RESOURCE CONSERVATION AND ALLOCATION VIA PROCESS
INTEGRATION

A Dissertation
by
DUSTIN ASHLEY HARELL

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

May 2004

Major Subject: Chemical Engineering
RESOURCE CONSERVATION AND ALLOCATION VIA PROCESS
INTEGRATION

A Dissertation

by

DUSTIN ASHLEY HARELL

Submitted to Texas A&M University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Approved as to style and content by:

________________________________ ________________________________
Mahmoud El-Halwagi Guy Curry
(Chair of Committee) (Member)

________________________________ ________________________________
Sam Mannan Charles Glover
(Member) (Member)

________________________________
Kenneth Hall
(Head of Department)

May 2004

Major Subject: Chemical Engineering
iii
ABSTRACT

Resource Conservation and Allocation via Process Integration. (May 2004)
Dustin Ashley Harell, B.S., Michigan Technological University
Chair of Advisory Committee: Dr. Mahmoud El-Halwagi

Throughout the process industry, the conservation and allocation of mass and energy
resources plays a pivotal role in the site wide optimization of a plant. Typically, raw
materials are transformed into products, byproducts and wastes through pathways
involving heating/cooling, pressure changes, mixing, reactions and separations. These
pathways often require the addition or removal of energy from the system. The optimal
management of such a system therefore requires conserving resources through the
appropriate allocation of materials and energy.

In a typical plant, there are both mass and energy objectives that require optimization.
This dissertation will focus on optimizing the mass and energy resources present in a
utility system. This will entail developing a novel framework of techniques to: target
and design steam cogeneration networks while minimizing fuel requirements,
identifying and utilizing sources of waste heat and incorporating heat pipes to enhance
heat exchange networks. Additionally, a specific case of waste recovery will be
examined when properties are the primary concern.
iv
DEDICATION
This dissertation is dedicated to my loving wife Georgina. Since our decision that I
would pursue a PhD, she has stood by my side regardless of the difficult times we have
faced both together and individually. Her quick-witted and high-spirited nature
constantly challenges me to improve myself both mentally and physically, and for that I
thank her. She has a loving and unselfish nature that is truly rare in today’s society, and
I am fortunate to have her by my side.
v
ACKNOWLEDGEMENTS
I wish to express my gratitude to my advisor, Dr. Mahmoud El-Halwagi, for providing
both guidance and encouragement during my career as a graduate student. His patience
for his students and novel approach to examining any problem are inspirational.

Many thanks to the numerous group members I have had the pleasure of working
alongside while I have been a student under Dr. El-Halwagi. I consider myself fortunate
to have been able to meet and interact with such a diverse group of people.

A special note of gratitude to Fred and Qin whom I spent many long hours with
discussing everything from research to Chinese politics while in the lab.

Finally, I would like to thank my loving parents for always supporting me in my
endeavors.
vi
NOMENCLATURE
AUP augmented property index
C1 cold stream 1
C2 cold stream 2
C3 cold stream 3
C4 cold stream 4
C average cluster of property i
i
C cluster of property i from source s
i,s
Cost cost of interception technology k
k
C heat capacity
p
C heat capacity of source s
p,s
e extractable energy
E extractable power
F flow rate
F flow rate of source s
s
F flow rate of source s to interceptor k
s,k
g a function
G flow rate of a sink
G flow rate to sink j
j
Glower lower bound on flow rate to sink j
j
Gupper upper bound on flow rate to sink j
j
vii
h a function
H enthalpy
H1 hot stream 1
H2 hot stream 2
H3 hot stream 3
H4 hot stream 4
Hin inlet enthalpy
Hout outlet header enthalpy
header
Hout outlet isentropic enthalpy
is
HEN heat exchange network
HP high pressure
HRSG heat recovery steam generation
i index of property
I binary integer for interceptor k
k
j index of sinks
k index of interceptors
K flow rate to interceptor k
k
K flow rate from interceptor k to sink j
k,j
Kint intercepted flow rate from interceptor k
k
LP low pressure or linear program
•
m mass flow rate
viii
M1 mass flow rate of header 1
M2 mass flow rate of header 2
M3 mass flow rate of header 3
M4 mass flow rate of header 4
MINLP mixed integer nonlinear program
MP medium pressure
N number of interceptors
int
N number of properties
prop
N number of sinks
sinks
N number of sources
sources
P average property
Pref reference of property i
i
P property of source s
s
q constant observed by Salisbury
Q heat load to be supplied by turbine
s index of sources
T sat inlet saturation temperature
in
T sat outlet saturation temperature
out
T supply temperature of stream s
supply,s
T target temperature of stream s
target,s
TID temperature interval diagram
u index of substreams
ix
VHP very high pressure
w specific work
W power
WHB waste heat boiler
x fractional contribution of source s
s
b cluster domain fractional contribution of source s
s
DHheader enthalpy difference between headers
DHisentropic isentropic enthalpy difference
DHreal actual enthalpy difference
DQC minimum cooling utility
min
DQH minimum heating utility
min
DT temperature difference in interval 1
1
DT temperature difference in interval 2
2
DT temperature difference in interval 3
3
DT temperature difference in interval 4
4
DT minimum temperature driving force
min
e power coefficient
h carnot efficiency
c
h header efficiency
header
h removal factor of interceptor k for property i
i,k
h isentropic efficiency
is
x
r density
W dimensionless property
y property operator
y (Psink) average operator of property i going to sink j
i i,j
y (P ) average operator of property i going to interceptor k
i i,k
y (Pint) intercepted operator of property i from interceptor k
i i,k
y (Plower) lower operator bound of property i for sink j
i i,j
y (Pupper) upper operator bound of property i for sink j
i i,j
y (Psource) operator of property i from source s
i i,j