114 santanu

S Bandyopadhyay 1/25

4th International Conference on Advances in Energy Research (ICAER-2013)

Pinch Analysis for Multi-Dimensional Sustainable Energy

Systems Planning

Raymond R. Tan De La Salle University, Manila, Philippines

Santanu BandyopadhyayIndian Institute of Technology Bombay, India



Classification of Design Activities

Hierarchical Analysis

InteractiveAutomatic

Qualitative

Quantitative

Heuristics Rules(rules of thumb)

Knowledge Based Systems (rule-based automated approaches)

Thermodynamic Methods(Pinch Analysis, Exergy Analysis)

Optimization Methods(Mathematical Programming, Stochastic Search Methods) Process Integration and

Optimization



What Is Process Integration?

Systematic and General Methods for Designing Integrated Production Systems, ranging from Individual Processes to Total Sites, with special emphasis on the Efficient Use of Energy and reducing Environmental Effects.

This definition points to design methods, but the term Process Integration is also used to describe physical arrangements such as the interconnection of equipment and process streams in a plant.



Categories of Process IntegrationMathematical optimization based methodologies: preferred to address issues like multiple contaminants,

controllability, flexibility, cost-optimality a good synthesis tool in handling complex systems with

different complex constraints major problems associated with these methodologies

are combinatorial explosion and local optimality do not provide good insight to the process designer

during network synthesis do not exploit special structures of these problems to

develop efficient algorithm



Categories of Process Integration-2Methodologies based on conceptual approaches: help in getting a physical insight through its graphical

representations and simplified calculation procedures efficient calculation procedure due to special structure

of these problems recognize the importance of setting targets before

design and allow different process design objectives to be screened prior to the detailed design

provides graphical representation tools and full control to the process designer over decision making processes

applicable to simple systems with simple constraints



Pinch Analysis

Pinch Analysis is a conceptual process integration approach

Pinch Analysis is a conceptual process integration approach

Development of simple and efficient algorithms by exploiting special structures



Heat Exchanger Network (HEN)

Birth of Pinch Analysis



Problem Definition for HEN Given:

a set of hot process streams to be cooled from the inlet temperatures to the outlet temperatures

a set of cold process streams to be heated from the inlet temperatures to the outlet temperatures

the heat capacities and flow rates of the hot and cold process streams

the external utilities available and the temperatures or temperature ranges as well as their costs

heat-exchanger cost data Objective:

To develop a network of heat exchangers with minimum annualized investment and operating costs



Historical Milestones Ten Broeck, 1944: First known HEN-related paper Westbrook, 1961: First use of mathematical programming for HEN Hwa, 1965: First use of a superstructure in HEN Hohmann, 1971: Composite curves to calculate of minimum

utilities requirement, and estimation for the minimum number of units (attempts to publish in journals were turned down twice)

Umeda et al., 1978 and Linnhoff and Flower, 1978: Identification of heat recovery pinch point (Starting point for Pinch Analysis)

Linnhoff and Hindmarsh, 1983: Pinch Design Method is proposed Furman and Sahinidis, 2001: Mathematical proof that this is N P-

hard (refuting the possibility for the existence of polynomial optimization algorithms → Sequential optimization)



Process Flowsheet

The starting point in the application of pinch technology is a simplified flowsheet showing major unit operations with heating and cooling duties.

2

3175°155°

112°

20°

40°

C385°

1 ReactorH1

45°

C4

125°H2

65°

1080

98°4

Steam

SteamCW

Heat Duty

CW

1320

1300 1400

kW

Ref: U. V. Shenoy, Heat Exchanger Network Synthesis, 1995, Gulf Pub. Com., Houston, Texas



Composite Curves

Composite Curves show the heat availability and heat requirement for the overall process

020406080

100120140160180200

0 2000 4000 6000 8000Enthalpy (kW)

Te

mp

era

ture

(°C

)No Integration

020406080

100120140160180200

0 1000 2000 3000 4000Enthalpy (kW)

Te

mp

era

ture

(°C

) Infeasible Integration

020406080

100120140160180200

0 1000 2000 3000 4000 5000Enthalpy (kW)

Te

mp

era

ture

(°C

) Process to process heat recovery

Min. Hot

Utility

Min. Cold Utility

Pinch



Can We Target the Minimum Energy Requirements in Algebraic Way?



“…some of the greatest advances in science have come about because some clever person spotted an analogy between a subject that was already understood, and another still mysterious subject.”

- Richard DawkinsThe Blind Watchmaker (1986)



Brief History of “Pinch”1970s Synthesis of heat exchanger network (HEN)

1994 Water minimization (water pinch)

1989 Synthesis of mass exchange network (MEN)

2002 Property integration (property pinch)

2007 Energy planning (carbon pinch)

1987 Synthesis of HEN for batch processes

2007 Isolated energy systems



Basic Problem Pattern Minimize use of scarce, high-quality stream Each stream source has fixed quality and quantity

characteristics Each stream demand has fixed quality and quantity

requirements Quality index is inverse and follows a linear mixing rule

What other problems follow a similar pattern?



Source: A stream which contains the targeted species. Each source has: Flowrate Fi Quality Qi

Quality load:

mi = Fi Qi

Source: A stream which contains the targeted species. Each source has: Flowrate Fi Quality Qi

Quality load:

mi = Fi Qi

Source/sink representation

Sink: An existing process unit/ equipment that can accept a source. Each sink has: Flowrate Fj

Quality Qj where:

Qjmin ≤ Qj ≤ Qj

max

Load capacity:

mi = Fi Qi

Sink: An existing process unit/ equipment that can accept a source. Each sink has: Flowrate Fj

Quality Qj where:

Qjmin ≤ Qj ≤ Qj

max

Load capacity:

mi = Fi Qi

Source i

j = 1

j = 2

Sink j

?j = 3

i = 1

i = 2

i = 3



Philosophy of Pinch AnalysisGeneralized Problem Definition and Solution:

Flows and Qualities Laws of thermodynamics, conservation relations Phenomenological relations, design correlations Overall optimization with system constraints Algebraic methodology Graphical representation

Setting Targets (Prediction of the optimum performance prior to any synthesis/ detailed design):

Physical insights to the designer Tool: preliminary analysis/directions for improvements Preliminary screening of design alternatives Step change to learning curves



Flows and Qualities in PA Flows Qualities Examples/Problems

Heat Temperature

Heat integration (1971, 1979)Total site integration (1984)Integration of thermal equipments (1982)

Mass Concentration

Mass integration (1989)Water/Hydrogen management(1994,1996)Pollution prevention/Treatment networks

Mass Properties Recycle/reuse networks (2004)

Steam Pressure Cogeneration (1993, 2008)

Energy CO2 Carbon-constraint energy planning (2007)

Mass Time Supply chain management (2002)

Energy TimeStand-alone energy system (2007)Isolated power system (2007)



The “PINCH” Concept Processes and Utility Systems From Scheduling to Strategic Planning Improving Efficiency (Energy and Raw Material) Continuous to Batch Processes All aspects of Processes: Reactors, Separators, etc. Integration between Processes Waste and Wastewater Minimization Emissions Reduction to Pollution Prevention Hydrogen Management Aggregate Production Planning Sizing Renewable Energy Systems ……… etc.



Sustainable Energy Systems Sustainable development meets the needs of the

present without compromising the ability of the future generations to meet their needs (Brundtland, 1987)

Sustainable energy systems provide energy services to the present while ensuring that similar energy services for future generations (Manish et al., 2006)

Atmospheric CO2 levels recently exceeded 400 ppm, (safe limit is 350 ppm, Rockstrom et al., 2009)

Sustainability indices: Economic cost EROI: energy return on investment (Hall, 1972) Land/water/carbon footprints ….. etc.



Problem Definition Given a set of energy sources (i = 1, 2, 3… m)

fixed EROI (EROIsi)

cost per unit energy (Csi)

carbon intensity or footprint coefficient (Fsi)

availability limits (Esimax)

Given a set of demands (j = 1, 2, 3… n). energy quantity (Edj)

quality (carbon emissions) specifications (Edj × Fdj)

Determine the source-sink mapping (system network) using EROI and cost as objectives

Multi-Objective optimization problem: Pareto optimal front using weighted-objective method



Case Study: Philippines

Ref.: DOE, 2013; Evans et al., 2009; Gupta et al., 2011

Region A Region BDemand 17,500 GWh 5,000 GWhCO2 limit (t/GWh) 500 200

Energy Sources

EROI Relative Cost CF (kg CO2/kWh) Limit (GWh)

Natural Gas 7 1.14 0.55 No limitCoal 18 1 1 No limitGeothermal 15 1.67 0.17 3,000Hydroelectric 40 1.19 0.04 10,000Wind 20 1.67 0.03 1,500Others 6 5.71 0.09 350



Pareto Optimal FrontMinimum energy invested solution (EROI-23.47, cost - 26773)

Wind and hydroelectric at maximum, coal (8958 GWh) and geothermal (2042 GWh).

800 900 1000 1100 1200 1300 1400 1500 160024500

25000

25500

26000

26500

27000

Total Energy investment (Ω)

Re

lati

ve

co

st

Co

st

(Φ)

Minimum cost solution (EROI-14.46, cost - 25380)

Hydroelectric at maximum, coal (5500 GWh) and natural gas (7000 GWh).

Mixed solution (EROI-17.78, cost - 25932)

Wind and hydroelectric at maximum, coal (7233 GWh) and natural gas (3767 GWh).



Conclusions Pareto optimal front is piece-wise linear in nature Weighted objective methods can identify only discrete optimal

points (where slope of the Pareto optimal front changes) Line joining consecutive optimal point is also optimum Extended pinch analysis method for multiple-objective source-sink

problems Concept of prioritized cost (Shenoy and Bandyopadhyay, 2007)

can be extended to address multi-objactive pinch analysis problems

Demonstrated with a case study of Philippines



Thank You

My father rode a camel. I drive a car. My son flies a jet plane. His son will ride a

camel. - Saudi proverb

[email protected][email protected]

114 santanu

Technology

pareto optimal

4th international

cold process

heat exchanger

process integration

process designer

problem definition

pinch analysis