Pinch analysis
Encyclopedia
Pinch analysis is a methodology for minimising energy consumption of chemical processes
by calculating thermodynamically feasible energy targets (or minimum energy consumption) and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions. It is also known as process integration
, heat integration, energy integration or pinch technology.
The process data is represented as a set of energy flows, or streams, as a function of heat load (kW) against temperature (deg C). These data are combined for all the streams in the plant to give composite curves, one for all hot streams (releasing heat) and one for all cold streams (requiring heat). The point of closest approach between the hot and cold composite curves is the pinch
point (or just pinch) with a hot stream pinch temperature and a cold stream pinch temperature. This is where the design is most constrained. Hence, by finding this point and starting the design there, the energy
targets can be achieved using heat exchangers to recover heat
between hot and cold streams in two separate systems, one for temperatures above pinch temperatures and one for temperatures below pinch temperatures. In practice, during the pinch analysis of an existing design, often cross-pinch exchanges of heat are found between a hot stream with its temperature above the pinch and a cold stream below the pinch. Removal of those exchangers by alternative matching makes the process reach its energy target.
under the supervision of Dr John Flower at the University of Leeds
. In 1977 Linnhoff joined Imperial Chemical Industries
(ICI) where he led practical applications and further method development. In 1982 he joined University of Manchester Institute of Technology (UMIST
, present day University of Manchester
) to continue the work. In 1983 he set up a consultation firm known as Linnhoff March International later acquired by KBC Energy Services.
Many refinements have been developed since and used in a wide range of industries, including extension to heat and power systems and non-process situations. Both detailed and simplified (spreadsheet
) programs
are now available to calculate the energy targets. A commonly used, free pinch analysis program is PinchLeni.
In recent years, Pinch analysis has been extended beyond energy applications. It now includes:
Process (engineering)
In engineering a process is a set of interrelated tasks that, together, transform inputs into outputs. These tasks may be carried out by people, nature, or machines using resources; so an engineering process must be considered in the context of the agents carrying out the tasks, and the resource...
by calculating thermodynamically feasible energy targets (or minimum energy consumption) and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions. It is also known as process integration
Process integration
Process integration is a term in chemical engineering which has two possible meanings.1. A holistic approach to process design which emphasizes the unity of the process and considers the interactions between different unit operations from the outset, rather than optimising them separately. This...
, heat integration, energy integration or pinch technology.
The process data is represented as a set of energy flows, or streams, as a function of heat load (kW) against temperature (deg C). These data are combined for all the streams in the plant to give composite curves, one for all hot streams (releasing heat) and one for all cold streams (requiring heat). The point of closest approach between the hot and cold composite curves is the pinch
Pinch
Pinch may refer to:* Pinch , the gripping of part of a substance, such as a powder or the skin* Pinch , a very small amount of an ingredient, typically salt or a spice* Pinch, West Virginia-Mathematics and Science:...
point (or just pinch) with a hot stream pinch temperature and a cold stream pinch temperature. This is where the design is most constrained. Hence, by finding this point and starting the design there, the energy
Thermal energy
Thermal energy is the part of the total internal energy of a thermodynamic system or sample of matter that results in the system's temperature....
targets can be achieved using heat exchangers to recover heat
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
between hot and cold streams in two separate systems, one for temperatures above pinch temperatures and one for temperatures below pinch temperatures. In practice, during the pinch analysis of an existing design, often cross-pinch exchanges of heat are found between a hot stream with its temperature above the pinch and a cold stream below the pinch. Removal of those exchangers by alternative matching makes the process reach its energy target.
History
The techniques were first developed in late 1977 by Ph.D. student Bodo LinnhoffBodo Linnhoff
Bodo Linnhoff is a chemical engineer who developed Pinch Analysis, a technique for minimizing energy usage in the process industries. In its early days, the technique helped companies such as ICI and BASF to design plants that used roughly 30% less energy...
under the supervision of Dr John Flower at the University of Leeds
University of Leeds
The University of Leeds is a British Redbrick university located in the city of Leeds, West Yorkshire, England...
. In 1977 Linnhoff joined Imperial Chemical Industries
Imperial Chemical Industries
Imperial Chemical Industries was a British chemical company, taken over by AkzoNobel, a Dutch conglomerate, one of the largest chemical producers in the world. In its heyday, ICI was the largest manufacturing company in the British Empire, and commonly regarded as a "bellwether of the British...
(ICI) where he led practical applications and further method development. In 1982 he joined University of Manchester Institute of Technology (UMIST
UMIST
The University of Manchester Institute of Science and Technology was a university based in the centre of the city of Manchester in England. It specialised in technical and scientific subjects and was a major centre for research...
, present day University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
) to continue the work. In 1983 he set up a consultation firm known as Linnhoff March International later acquired by KBC Energy Services.
Many refinements have been developed since and used in a wide range of industries, including extension to heat and power systems and non-process situations. Both detailed and simplified (spreadsheet
Spreadsheet
A spreadsheet is a computer application that simulates a paper accounting worksheet. It displays multiple cells usually in a two-dimensional matrix or grid consisting of rows and columns. Each cell contains alphanumeric text, numeric values or formulas...
) programs
Computer program
A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...
are now available to calculate the energy targets. A commonly used, free pinch analysis program is PinchLeni.
In recent years, Pinch analysis has been extended beyond energy applications. It now includes:
- Mass Exchange Networks (El-Halwagi and Manousiouthakis, 1987)
- Water pinch (Yaping Wang and Robin Smith, 1994; Nick Hallale, 2002; Prakash and Shenoy, 2005)
- Hydrogen pinchHydrogen pinchHydrogen pinch analysis is a hydrogen management method that originates from the concept of heat pinch analysis. HPA is a systematic technique for reducing hydrogen consumption and hydrogen generation through integration of hydrogen-using activities or processes in the petrochemical industry,...
(Nick Hallale et al., 2003; Agrawal and Shenoy, 2006)
See also
- CHP DirectiveCHP DirectiveThis refers to the Directive on the promotion of cogeneration based on a useful heat demand in the internal energy market and amending Directive 92/62/EEC, officially 2004/8/EC and popularly better known as the 'Combined Heat and Power Directive'...
- Energy policy of the European UnionEnergy policy of the European UnionAlthough the European Union has legislated in the area of energy policy for many years, and evolved out of the European Coal and Steel Community, the concept of introducing a mandatory and comprehensive European energy policy was only approved at the meeting of the European Council on 27 October...
- Euroheat & powerEuroheat & PowerEuroheat & Power is a pan-European trade association of district heating operators and related companies and associations.Euroheat & Power unites the combined heat and power, district heating and cooling sector throughout Europe and beyond, with members from over thirty countries: including...
- Relative cost of electricity generated by different sources
- CogenerationCogenerationCogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
- Process flowsheetingProcess flowsheetingProcess flowsheeting is the use of computer aids to perform steady-state heat and mass balancing, sizing and costing calculations for a chemical process.The process design effort may be split into three basic steps* synthesis* analysis and* optimization....
- Review of process integration and pinch analysis by Nick Hallale (University of Manchester)
Pinch analysis software
- Pinchleni - Freeware developed by Laboratoire d'Energétique Industrielle de l'Ecole Polytechnique Fédérale de Lausanne, Switzerland Pinchleni
- Online Pinch Analysis Tool - Free for personal and educational use, hosted by the College of Chemical Engineering at the University of Illinois at ChicagoUniversity of Illinois at ChicagoThe University of Illinois at Chicago, or UIC, is a state-funded public research university located in Chicago, Illinois, United States. Its campus is in the Near West Side community area, near the Chicago Loop...