CN4205R

Pinch Analysis and

Process Integration

Sachin V JANGAM

Department of Chemical and Biomolecular Engineering

National University of Singapore

Singapore

Email: chejsv@nus.edu.sg

Office location: E4-05-46

AY 2016-17

Introduction

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Energy: Use, Recovery, Reuse and

Efficiency

Heat Exchanger Networks

• Pinch Analysis

• Industrial Experience

Process Integration

Process Data Analysis

Syllabus and Schedule

Learning Outcomes

Books/References

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(Source: https://www.iea.org/publications/freepublications/publication/KeyWorld_Statistics_2015.pdf)

Energy: Worldwide usage Coal Oil

Electricity

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Source: https://www.ema.gov.sg/cmsmedia/Publications_and_Statistics/Publications/ses/2015/energy-

consumption/index.html

Energy Use: Statistics for Singapore

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Industry Responsible for CO2 Emission

World's CO2 emissions by sector in 2013

Source:

http://www.iea.org/publications/freepublications/publication/CO2EmissionsFromFuelCombustionHighlights2

015.pdf

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Energy Savings Potential for Industrial Sectors

4-Step Approach

o Data Acquisition & Process Simulation

o Mass & Energy Balance Analysis

o Application of Process Integration Techniques

o Techno-economic Evaluation of Selected Projects

(Source: http://www.nrcan.gc.ca/energy/efficiency/industry/processes/systems-

optimization/5495

Energy: Recovery, Reuse and Efficiency

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Energy: Recovery, Reuse and Efficiency

Success Stories of Process Integration

o Chemical

o Food and Drink

o Pulp and Paper

o Oil Refining

o Textile

Energy Efficiency in ExxonMobil

(Source: http://www.exxonmobil.com.sg/Corporate/energy_ops_efficiency.aspx)

o Global Energy Management System (GEMS)

o 2002-2011: Energy Efficiency Improved by 9% in Refining and

by 12% in Chemicals

(Source: http://canmetenergy.nrcan.gc.ca/industrial-processes/industrial-systems-

optimization/process-integration/success-stories/76)

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Energy: Recovery, Reuse and Efficiency

GSK in Singapore

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Energy: Recovery, Reuse and Efficiency

Industry Energy Efficiency (Technology Roadmap)

o Refinery and chemical plant integration

o Supercritical CO2 cycle Heat recovery systems and other low-

grade waster heat recovery systems

o Pinch analysis

Petroleum refining: 2030 technical potential energy savings

2030 Technical potential energy savings contribution, by subsector

Source: https://www.nccs.gov.sg/sites/nccs/files/Roadmap_IEE_1.pdf

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The process design hyerarchy

Reactor

Separation/

Recycle System

Heat Recovery

System

Heating & Cooling

Utilities

Water & Effluent

Treatment

Onion Diagram

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Heat Exchanger Networks

Chemical Process/Plant

Heat Exchanger Network

Steam (Hot Utility) = 1652 + 70

= 1722 kW

Cooling Water (Cold Utility) = 654 kW

Number of Units = 6

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Heat Exchanger Networks

Pinch Analysis – HEN

Design with Targets

Steam = 1068 kW

Cooling Water = 0 kW

Number of Units = 4

Reduction:

Steam = 1722-1068 = 654 kW

CW = 654 kW

Units = 2

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Heat Exchanger Networks

Industrial Experience

ICI, UK

• Crude Preheat Train (Section 9.2, Kemp)

• Bulk Chemical Plants to Specialty Units

• Energy Savings of ~ 30%

Union Carbide, USA

• Better Results than ICI

BASF, Germany

• Over 150 Projects

• Energy Savings of > 25% from Retrofitting

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Heat Exchanger Networks

Why Does Pinch Analysis Work?

Conventional Approach

• Problem and Solution/Design

Role of Thermodynamics

Approach in Pinch Analysis

• Problem, Targets and Solution/Design

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Heat Exchanger Networks

Cost Considerations

Capital Cost (CC) for Units

• Exchangers, Heaters, Coolers

Operating Cost (OC)

• Utilities/Energy

• Pumping Cost

CC and OC are often conflicting

Pinch analysis may reduce both CC and OC

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Process Integration

Deals mainly with optimal use of

Heat

Utilities

Also, considers environmental protection,

control and safety aspects

The approach consists of developing

alternatives to arrive at cost-effective and

sustainable solutions

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Process Integration

Heat and Power Systems

Interaction of heating and cooling utilities

with power requirements

• Combined heat and power (CHP) systems

• Heat pump and refrigeration systems

• Steam systems and cogeneration

• Total site analysis - Optimizing the heating,

cooling and power requirements of entire

plant

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Process Integration

Process Modifications for Energy

Efficiency

Distillation column

• Distillation sequencing – heat integration

characteristics

• Heat pumping in distillation

Evaporators and Dryers

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Process Integration

Wastewater minimization

Water use in process industries

Targeting and design for maximum water

reuse for single contaminants

Process changes to reduce water

consumption

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Process Data Analysis

Process Measurements

Measured process data Inevitably contain some

inaccurate information

Observed value of measured variable is

composed of true value and some error value

(random or gross error)

Leads to significant deterioration of plant

performance

Important to estimate true condition of process

state ‘using measurements’, for process control

and optimization

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Process Data Analysis

Data Reconciliation (DR)

Estimation of process variables based on process

measurements and models (usually mass and

energy conservation equations)

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Process Data Analysis

Gross Error Detection

Companion technique to data reconciliation, to

identify and eliminate gross errors

DR is based on the assumption that only

random errors are present. When gross error is

present, gross error detection techniques are

used to improve accuracy of reconciled data

Makes use of a statistical test known as

‘measurement test’

Industrial applications

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Syllabus

Overview (1 hour)

Pinch Analysis (12 hours)

Basic Concepts of Pinch Analysis (Data Extraction, Energy Targeting,

Supertargeting), and Heat Exchanger Network Design (Basic Principles,

Stream Splitting, Network Relaxation, Retrofit Design)

Process Integration (16 hours)

Heat Integration Issues for Utilities, Heat and Power Systems (Combined

Heat and Power, Heat Pumps, Refrigeration Systems, Total Site Analysis),

Process Modifications for Energy Efficiency (applied to Distillation

Columns), Wastewater Minimization, Project Presentations

Process Data Analysis (10 hours)

Data Reconciliation, Gross Error Detection and Identification, Multiple

Gross Errors, Industrial Applications

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Lectures and Tutorials indicated in the

following table will be held in E5-02-32 (Wed).

Each of the many sessions includes tutorial

for about one hour.

The details of changes (if any) will be

discussed in the class and communicated

through IVLE

Schedule

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Tentative Schedule

No. Date Topic

1 TBA Overview, Pinch Analysis (Basic Concepts)

2 TBA Pinch Analysis (Basic Concepts)

3 TBA Pinch Analysis (Heat Exchanger Network Design)

4 TBA Pinch Analysis (Heat Exchanger Network Design)

5 TBA Lecture on Process Integration (Heat Integration Issues for Utilities)

6 TBA Test 1 on Pinch Analysis; Process Integration (Heat and Power

Systems)

7 TBA Process Integration (Process Modifications for Energy Efficiency)

8 TBA Process Integration (Process Modifications for Energy Efficiency;

Wastewater Minimization)

9 TBA Process Integration (Wastewater Minimization), Process Data Analysis

(Data Reconciliation)

10 TBA Lecture on Process Data Analysis (Data Reconciliation, Gross Error

Detection and Identification)

11 TBA Test 2 on Process Integration; Process Data Analysis (Gross Error

Detection and Identification)

12 TBA Process Data Analysis (Multiple Gross Errors, Industrial Applications);

Project Presentations

13 TBA Test 3 on Process Data Analysis; Project Presentations

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Learning Outcomes

On successful completion of this module, students will be

able to:

1. Extract stream data, and find targets for heat exchanger network

synthesis

2. Design and evolve heat exchanger networks

3. Reduce utility loads in chemical process industries by using

energy recovery techniques

4. Analyse opportunities for altering process operating conditions

for cost savings by maximizing heat integration

5. Reconcile, detect and identify gross errors in industrial/

measured data

6. Work on a group project to improve energy efficiency of a

chemical process using the concepts taught in this module, and

communicate the work

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Assessment

CA – 100% (No Final Examination)

Test 1 on Pinch Analysis: 22%

Test 2 on Process Integration: 28%

Test 3 on Process Data Analysis: 15%

Project (Reports and Presentation): 35%

May require minimum use of HYSYS, only in the later part of the

project (towards the end of semester)

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Books/References

1. Pinch Analysis and Process Integration: A

User Guide on Process Integration for

Efficient Use of Energy, I.C. Kemp, 2nd

Edition, Butterworth-Heinemann (2007)

2. Chemical Process Design and Integration, R.

Smith, John Wiley (2005)

3. Narasimhan S. and Jordache C., “Data

Reconciliation and Gross Error Detection: An

Intelligent Use of Process Data”, Gulf

Publishing (1999).