Pinch analysis for energy and carbon footprint reduction user guide to process integration for the efficient use of energy PDF
Preview Pinch analysis for energy and carbon footprint reduction user guide to process integration for the efficient use of energy
PINCH ANALYSIS FOR ENERGY AND CARBON FOOTPRINT REDUCTION In memoriam Dad and Sue Foreword to the first edition Everynowandthen,thereemergesanapproachtotechnologywhichisbrilliant—in conceptandinexecution.Ofcourse,itturnsouttobebothsimpleandpractical.Because of all these things, it is a major contribution to the science and art of a profession and discipline. BodoLinnhoffandtheothermembersofthisteamhavemadeamajorcontributionto chemicalengineeringthroughtheirwork.Itisalreadyrecognisedworldwide,andIhave personal experience of the acclaim that the techniques embodied in this guide have received in the United States. There is no need to underline the necessity for more efficient use of energy: the chemical industry is a very large consumer, as a fuel and as a feedstock. What is equally importantisthatconceptualthinkingofahighorderisnecessarytoourindustrytokeep advancing our technologies to reduce both capital and operating costs. The guide pro vides new tools to do this, which forces the sort of imaginative thinking that leads to major advances. Itisalsoimportanttonotethattheemphasisintheguideisonstimulatingnewcon cepts in process design that are easily and simply implemented with the aid of no more thanapocketcalculator.Inthesedays,whentheteachingandpracticeofmanyapplied sciencestendheavily towardsmathematical theoryand theneedfor sophisticatedcom puterprogrammes,ahighlyeffective,simpletoolthatattainsprocessdesignexcellenceis very timely. R. Malpas Halcon International New Jersey, USA ix Foreword to the second edition The original UserGuide waspublishedmorethan 20years ago, andit isprobably a case of: … “from small acorns big oak trees grow.” Innovation is fascinating. John Lennon once said: “Reasonable people adapt to the world. Unreasonable people want the world to adapt to them. It follows that all inno vation is due to unreasonable people.” IneverthoughtofIanKempasunreasonable,butasayoungengineer,hedidjoinup with those of us who innovated a (then) novel and unorthodox approach to energy management in process design. He became one of the most committed practitioners I remember meeting. It’sfitting that itis Ian who showedthestaying power to produce, 20yearson,thisreallabouroflove,thesecondedition,withmorethandoublethenum ber of pages. Detail, complexity, and sheer volume are often a sign of maturity. As a technology develops,thebooksgetlonger.It’sacommontrendandoftenathanklesstask.Onbehalf of many process design professionals, I thank Ian for tackling this task. Bodo Linnhoff Berlin, Germany x Preface We live in a world of finite fossil fuel resources and an ever increasing threat of climate change. Pinch analysis is a key tool to help us understand the heat and power requirements of a process or site and satisfy them in a way that minimises energy con sumption and carbon footprint. IsaacNewtonsaidthatwhenweseefurtheritisbecauseweare“standingontheshoul dersofgiants.”Forpinchanalysis,thegiantsareBodoLinnhoffandhiscolleaguesatICI andUMIST(nowManchesterUniversity),whotookapromisingideaanddevelopedit intopracticalmethodsgivingrealenergyandcostsavings.Insteadofreamsofequationsor complex computer models, here were straightforward techniques giving fundamental newinsightsintotheenergyuseofprocesses.Rigorousthermodynamicallybasedtargets enabledengineerstoseeclearlywhereandwhytheirprocesseswerewastingenergyand how toputthem right.A key insightwas theexistence ofa‘pinch’temperature,which was the source of the term ‘pinch analysis’ to describe the new methodology. WhenthefirsteditionoftheUserGuideonProcessIntegrationappearedin1982,it wasinstantlyrecognisedasaclassicfortheeleganceandsimplicityofitsconceptsandthe clarity with which they were expressed. It provides the backbone of the present book, supplying nearly half the material, often verbatim but with judicious reordering and expansion. The second edition of 2007 added later discoveries on process change, sep aration systems, batch processes, and industrial applications, and this third edition includes carbon footprint considerations and the water, hydrogen, and carbon pinch. It still aims to be a practical tool for the engineer and does not attempt to duplicate or replace the detailed research papers and texts on the subject that have appeared in the last 40 years, but makes reference to them as appropriate. Chapter 1 introduces the concepts, and Chapter 2 lays the foundations of energy, heat, and power and their relation to carbon footprint. Chapter 3 describes the key aspects—energy targeting, graphical representation through the composite and grand compositecurves,andtheideaofthepinch,showinghowthisiscentraltofindingaheat exchangernetworkthatwillmeetthetargets.Hopefully,thiswillwhetthereader’sappe titeforthemoredetaileddiscussionoftargetingforenergy,areaandcost(Chapter4),and network design and optimisation (Chapter 5). Chapter 6 describes the interaction with heatandpowersystems,includingCHP,heatpumpsandrefrigeration,andtheanalysisof totalsites.Beneficialchangestooperatingconditionscanalsobeidentified,asdescribed in Chapter 7, especially for distillation, evaporation, drying, and other separation pro cesses,whilstChapter8describesapplicationtobatchprocesses,start upandshutdown, and other time dependent situations. Chapter 9 extends the techniques to water and hydrogen networks and the carbon pinch. xi xii Preface The final sections look more closely at practical application. Chapter 10 gives guid anceonapplyingthemethodologyinrealindustrialpractice,includingthevitalbutoften neglectedsubjectofstreamdataextraction.Chapter11showshowpinchanalysiscanbe used in a range of industries. Twocasestudiesrunlikeconstantthreadsthroughthebook,beingusedasappropri ate to illustrate the various techniques in action. Six further complete case studies are covered in Chapter 12, and others are mentioned in the text. Itisamyththatpinchanalysisisonlyapplicabletolargecomplexprocesses,suchasoil refineriesandbulkchemicalsplants.Evenwherecomplexheatexchangernetworksare unnecessaryandinappropriate,pinchanalysistechniquesprovidethekeytounderstand ingenergyflowsandensuringthebestpossibledesignandoperation.Thus,aswillbeseen in the text and in particular the case studies, it is relevant to smaller scale chemical processes, food and drink, consumer products, batch processing, and even non process situationssuchasbuildings.Often,smallandsimpleplantsstillrevealworthwhilesavings, becausenobodyhasreallysystematicallylookedforopportunitiesinthepast.Reducing energyusagebenefitsthecompany(everypound,dollaroreurosavedreducesdirectcosts andgoesstraightonthebottomlineasincreasedprofit)andtheenvironment(bothfrom reduced fossil fuel usage and lower emissions). And even if no major capital projects result, the engineer gains substantially in their understanding and ‘feel’ for their plant. Inseveralcasesapinchstudyhasledtoimprovedoperationalmethodsgivingasubstantial saving—at zero cost. Formanyyearsabarriertothemorewidespreadadoptionofpinchanalysiswasalack ofaffordablesoftware.ToremedythistheInstitutionofChemicalEngineersranacom petition for young members in 2006 to produce a spreadsheet for pinch analysis to accompanythesecondedition.Theentrantsshowedagreatdealofingenuityanddem onstratedconclusivelythatthekeytargetingcalculationsandgraphscouldbegenerated in this way, even without widespread use of programming techniques such as macros. Special congratulationsareduetoGabrielNorwood,whoproducedthewinningentry that is available to download free of charge with this book. Nowadays, therefore, there is no reason why every plant should not have a pinch analysisandaheatandmassbalance,aprocessflowsheet,andapipingandinstrumenta tiondiagram.(Thatbeingsaid,itissalutarytoseehowmanycompaniesdonothavean up to date, verified heat, and mass balance; this is often one of the most valuable by products of a pinch study!) Ourhopeisthatthislatestrevisionwillinspireanewgenerationofengineers,scien tists, and technologists to apply the concepts in processes and situations far beyond the areas where it was originally used, benefiting our many and varied organisations and our one shared planet. Ian C. Kempa, Jeng Shiun Limb aWare, Hertfordshire, United Kingdom bJohor Bahru, Malaysia Acknowledgements Much of the material in the original User Guide has stood the test of time, and it is pointless to reinvent the wheel. A significant proportion of the text and figures in Chapters1,3–6,and12ofthisbookisreproducedfromthefirstedition.Wearegrateful totheIChemEandProfessorLinnhofffor givingusthepermissiontousethismaterial, whichmadethewritingofsubsequenteditionsamanageabletaskratherthananimpos sible one, and we are only too happy to acknowledge our debt to the original team of authors: B. Linnhoff, D.W. Townsend, D. Boland, G.F. Hewitt, B.E.A. Thomas, A.R. Guy, and R.H. Marsland, plus the additional contributors. Many other people have had an influence on this book. Ian Kemp was fortunate enough to attend one of Bodo Linnhoff’s early courses at UMIST and to be trained by several members of the pioneering ICI research and applications teams, particularly Jim Hill, Ajit Patel, and Eric Hindmarsh. I am profoundly grateful to them and also to my colleagues at Harwell Research Centre, particularly Ewan Macdonald who gave me much valuable guidance as a young engineer. Of the many others who have influ enced me over the years, I would particularly like to mention John Flower and Peter Heggs. RobinSmith,GeoffHewitt,GrahamPolley,andAlanDeakinmadesignificantcon tributionswhenthesecondeditionwasfirstmooted.Ourthanksalsogotooureditorsat Elsevier for their assistance through the publishing process. Lastbutnotleast,wewouldliketothankourfamilies fortheir unwaveringsupport and patience during the writing and preparation. Figure acknowledgements The authors acknowledge with thanks the assistance given by the following companies and publishers in permitting the reproduction of illustrations from their publications: AmericanChemicalSocietyforFigs9.11–9.13fromEl Halwagi,M.M.etal.(2003), Industrial & Engineering Chemistry Research, vol. 42, pp. 4319–4328, Figs 9.17–9.21 fromWanAlwi,S.R.andManan,Z.A.(2008),Industrial&EngineeringChemistryResearch, vol.47,pp.2762–2777,Fig.9.29fromFoo,D.C.Y.andManan,Z.A.(2006),Industrial& EngineeringChemistryResearch,vol.45,pp.5986–5995andFig.9.38fromLee,S.C.etal. (2009),AppliedEnergy,vol.86,pp.60–67. Elsevier Ltd for Fig. 4.20 from Linnhoff, B. and Ahmad, S. (1990), Computers and Chemical Engineering, vol. 7, p. 729, Fig. 6.19 from Klemes, J. et al. (1997), Applied Thermal Engineering, vol. 17, p. 993, Fig. 9.22 from Wan Alwi, S.R. et al. (2009), xiii xiv Acknowledgements Resources,Conservation&Recycling,vol.53,pp.588–591andFigs9.23and9.24from Prakash, R. and Shenoy, U.V. (2005), Chemical Engineering Science, vol. 60, pp. 255–268. John Wiley and Sons for Figs 6.20, 6.21, 6.24, and 7.16 from Smith, R. (2005), Chemical Process Design and Integration, Figs 9.4–9.7 from Manan, Z.A. et al. (2004), AIChE Journal, vol. 50, pp. 3169–3183 and Fig. 9.25 from Agrawal, V. and Shenoy, U.V. (2006), AIChE Journal, vol. 52, pp. 1071–1082. SpringerNatureforFig.2.3fromAndersNordelo€fetal.(2014),TheInternationalJour- nal of Life Cycle Assessment, vol. 19, pp. 1866–1890. The Institution of Chemical Engineers (IChemE) for Fig. 7.15 from Smith, R. and Linnhoff, B. (1988), TransIChemE Part A, vol. 66, p. 195. Woodhead Publishing Limited for Figs 9.1, 9.8, and 9.9 from Wan Alwi, S.R. and Manan, Z.A. (2013), Handbook of Process Integration (PI). And special thanks to the IChemE and Professor Bodo Linnhoff for giving us the permission to use many of the figures from the first edition.
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