Pinch Technology

Introduction

Chapter 1 Pinch Technology 1

Contents

1.	Pinch Technology			2
	1.1	What this chapter contains...........................................................................................		2
	1.2	What is Pinch Technology?.........................................................................................		2
	1.3	From Flowsheet to Pinch Data ....................................................................................		3
		1.3.1	Data Extraction Flowsheet..............................................................................	3
		1.3.3	Thermal Data ..................................................................................................	4
	1.4	Energy Targets ............................................................................................................		5
		1.4.1 Construction of Composite Curves.................................................................		5
		1.4.2 Determining the Energy Targets.....................................................................		6
		1.4.4	The Pinch Principle.........................................................................................	7
	1.5	Targeting for Multiple Utilities ...................................................................................		8
		1.5.1 The Grand Composite Curve ..........................................................................		8
		1.5.2 Multiple Utility Targeting with the Grand Composite Curve .......................		10
	1.6	Exergy Analysis ........................................................................................................		11
		1.6.1	Carnot factor calculations .............................................................................	11
		1.6.2 Constructing an exergy balance....................................................................		12
	1.7	Capital - Energy Trade-offs.......................................................................................		12
		1.7.1	New Designs.................................................................................................	13
		1.7.2	Retrofit..........................................................................................................	15
	1.8	Process Modifications ...............................................................................................		22
		1.8.1 The plus-minus principle for process modifications.....................................		22
		1.8.2	Distillation Columns.....................................................................................	23
	1.9	Placement of Heat Engines and Heat Pumps.............................................................		27
		1.9.1	Appropriate integration of heat engines ........................................................	27
		1.9.2 Appropriate integration of heat pumps .........................................................		29
	1.10	Heat Exchanger Network Design ..............................................................................		30
		1.10.1 The Difference Between Streams and Branches.........................................		31
		1.10.2 The Grid Diagram for heat exchanger network representation...................		32
		1.10.4 The New Design Method............................................................................		34
		1.10.5 Heat Exchanger Network Design for Retrofits ...........................................		41
	1.11	Data Extraction Principles.........................................................................................		50
		1.11.1 Do not carry over features of the existing solution .....................................		50
		1.11.2 Do not mix streams at different temperatures.............................................		52
		1.11.3 Extract at effective temperatures ................................................................		53
		1.11.4 Extract streams on the safe side..................................................................		53
		1.11.5 Do not extract true utility streams...............................................................		54
		1.11.6	Identify soft data .........................................................................................	55
	1.12	Total Site Improvement.............................................................................................		55
		1.12.1 Total site data extraction.............................................................................		56
		1.12.2	Total site analysis .......................................................................................	58
		1.12.3 Selection of options: Total Site Road Map .................................................		61
	1.13	References .................................................................................................................		64
	1.14	Glossary of Terms .....................................................................................................		66
2.	Index			71

Pinch Technology Introduction

2

Pinch Technology

Chapter 1

1. Pinch Technology

1.1 What this chapter contains

This material aims to give an overview of the fundaments of Pinch Technology. You will learn:

•How to obtain energy targets by the construction of composite curves.

•The three rules of the pinch principle by which energy efficient heat exchanger network designs must abide.

•About capital-energy trade off for new and retrofit designs.

•The best way to make energy saving process modifications.

•How to do multiple utility placement.

•How best to integrate distillation columns with the background process.

•The most suitable way to integrate heat engines and heat pumps.

•The principles of data extraction.

•Some of the techniques applied in a study of a total site.

The text covers all aspects of the technology employed in the SuperTarget suite from KBC [4]. This suite allows the user to carry out an in-depth pinch analysis, using the PROCESS, COLUMN and SITE modules.

1.2 What is Pinch Technology?

Pinch Technology provides a systematic methodology for energy saving in processes and total sites. The methodology is based on thermodynamic principles. The Figure below illustrates the role of Pinch Technology in the overall process design. The process design hierarchy can be represented by the "onion diagram" [2, 3] as shown below. The design of a process starts with the reactors (in the "core" of the onion). Once feeds, products, recycle