Apc for min maintenance or max profit -part 2
2
H P I N CONTROL PIERRE R. LATOUR, GUEST COLUMNIST [email protected] APC for min maintenance or max profit?—Part 2 While I have promoted proper control system performance indicators'""^'' since 1964, like Dr. Y. Zak Friedman,' 1 also am ,iware of some deeper problems with realizing its full commercial potential.-*'"""*''^'^'^' Friedman once piiblically claimed Clifftcnt"^'^ w,is no panacea,"' without seeing ii in action. Moreover, he LÍi.irged, without any basis, that C'liHtenr, a mathematical pro- cedure, could lead to burning down a furnace. My experience is proper deployment of CÜiflrent to operate the HPI would mitigate Micb events''' because ii mandates caretul modeling ofthe financial consequences of exceeding properly set limits like burning down liirnace.s, so operators would be using better information and models to make appropriate .sctpoint decisions for risky tradeoffs. I >etermining .sucb effects rather than ignoring them is the main idea of science, mathematics and engineering. I refrain from blam- ing MVC^, I'll), IP. SQC. feed-forward, inferentials, six-sigma, .statistics, talculu.s or tiialhematics for burning down furnact'.s. I have published practical examples ol using Clifftent to calcu- late APC benefits many times for real applications'"'''''*'"^^'^*' since [be tow-MiIlur fuel oil example^'* in HP, December 1996. I bavc .1 library ot commercial oil refmery, olefln, aromatics, polymer, synluels, chemicals and gas processing applications now. Every single one is a success because it determines a profit improvement (.sometimes small) and bow to achieve it. I recently sbowed^^ how to (¡uaiitify the value of Friedmans alkylation control approach."^'' As for how Clifftent works, 1 have published that too^"''''^''^*^'*'^^''^* and will repeat it here. Every controlled vari- -ible iCV) has a risky profit tradeoff. Calculus and statistics teach integration ofthe product of a data frequency di.stribution with its associated profit function gives its average (expected value) profit. Repeated integrations witb incremented data means give ihe average profit profile vs. data mean; a smooth hill (for any sianilard deviation >Ü). It's easy to locate the hilltop max profit .md corresponding optimum data mean. Thats how all HI'l sctpoints, limits, targets and specs are set now, although witb less rigor. That's also bow C.VIKPi profit meters can be built. ' 1 he HPI received the panacea in 1996."' A Canadian University ChE Department included deter- mining dynamic system financial performance, ClifTtent, in it.s process control course in September 2009. Hopefully this rekindled academic interest in process control and research on building Clifftent models for integrated alarm management, process maintenance and safety. Once a set of candidate CKs ;ind related manipulated variables (Af Ks) are established and I be pracess operation and économies are known, good process control engineering practicc^'^'''''^'^'^'"^^'^'* calls for determining tbe economic sensitivity of eacb CV, their Clifftents and a vari- ,nice reduction claim for each control system design, providing ihf appropriate sctpoint determination method and benefit for ihat variance reduction. 7 hen the process control engineer is in a •>olid position to design, m;untain and improve the Instruments and control system, the process operator is in a sound posiiuin to use it and operating company management understands it.s role and value. They finally have a chemical engineering method for operation that is pragmatic, prudent and profitable. ln hct, 1 claim had one or iwo computer-integrated manufaciur- ing (CIM) solution suppliers adopted pcrtormancc-based licensing when it was commercialized in the mid-199üs,^"'^'^'*'^^ the land- scape of the APC, and (^IM business in the HPI today would he healthier, more significant and more profitable lor those suppliers and their operating company partners. And much misguided effort and cxpcase would have heen avoided. fViedman wouid certainly not he proposing in a 2009 HP editorial forgoing .ÍO'^íi of APC'.perfor- mance, worth >$ü.3()/bbl crtidere-fined,to reduce AI'C. maintetiatice cxjsts. It would not he pragmatic, prudent or profitable. Dr Y. Zak Friedman's HPln Control editorials continue to serve the HPI. 1 hope I can add to them on occasion. W* LITERATURE CITED '" l^tour. V. R.. "Why Invesi in PRt}CRSS CONIROL?". CONTROL Vol. XV. x\S. May 2002. pp. 41-46. ''' l^aiiiur. P R., "Why tune control loops? Wby mdte control loops?", ediio- rial guest columnist, Hydrocarbon Processing, V 8 I . n9. September 2(102. pp. '" McMahon.T K., (& P. R. Latour). "CLIFFTENT For Process Optimization." CONTROL VI7. nl2. December 2004, p. 66. '' l^tdur. P R., "Detisions about risk reduction." litter to Editor, Hydrocarhon Processing, V80. n6, June 2001, p. 3'). ^^ Latoiit. I'. R.. "Quantifying financial values", HP In Control Guest Columnist. Hydrucarhm lhvcrssir,g.V%{i, n7. July 2001. pp. 13-t4. '' ljtoiir. P. R., "Align alkybiion separaiiiin to economics." HPln Cx)ntrol liditorial, Hydrociirbiiti Processing, VHS. i i ! , lanuary 2009. p. 98. ^'' Latour. ['. R.. "Process control: t'l.ll'i'TIÍN I siiows its more profitable than ex|TecEed," Hydnittirhon froressing, V7'i, nl2. December 1')%. pp. 7S-H(). Repiibliühed in Kane. [.es. VA, Aduamrii Process Control ami Informniion Sysifim for the l^ocess ¡ndustrirs. Gulf Piiblisliing, Co. I')')'>. pp. .ÍI-37. ^'' Ldoiir. P. R.. "CLIFHIHNT: Determining I-ull Financial Benefit from Improved Dynamic Performance." PajierCOI, ihirJ Intcrnarioual Conference on l-dundaiions of C\)mpurer-Aided Process Operations. Snowbird, Utah. )uly "i—IO, l')')8. Proceedings published in AlChK Symposium Series No. 320. V94. 1998. pp. 297-302. ^'' Baker. J. A. et ul. "The Rc]X)ri o f l l i e BP U.S. Refineries Independent Safety Review Panel." January 2007. ^' Friedman, Y. Z., (& G. D. Martin. P R. Latour). "APC Survey," Exchange of Ixiiters to the Fldiior, Hydrocarbon Prficessirig., V85. nlO. OttoUr 2006. pp. 45-46 and V85, n i l . November 2006. pp. 45-52. '" l^tour. lî R.. "Align Olefin Operations to Lxonomics - Clifiicnt optimizes scipoints." pn-senteil at 2007 Spring AlChF. Meetinj^ Ethylene Producers Conference, Houston. Tex;«, April 2^. 2007. Published in t^onfcrcnce Proceedir^s C D . ''' Fricdnian. Y. Z., "Alkylatioti prcKluci separation control," HPIn Conttol editorial. Hydrocarbon Processing, V87, n9. September 2008, p. 178. The author, president of CLIFFTENT Inc., is an independent conr.ulting chemic.il engineei specializing in identifying, capturing and sustaining measurable financial value from HPI dynamic process control, IT and CIM solutions (CLIFFTENT) using performance-based shared risk-shared reward (SR2) technology licensing HYDROCARBON PROCESSING NOVEMBER 2009 13
Transcript of Apc for min maintenance or max profit -part 2
HPIN CONTROL
PIERRE R. LATOUR, GUEST COLUMNIST
APC for min maintenance or max profit?—Part 2While I have promoted proper control system performance
indicators'""^'' since 1964, like Dr. Y. Zak Friedman,' 1 also am,iware of some deeper problems with realizing its full commercialpotential.-*'"""*''^'^'^' Friedman once piiblically claimed Clifftcnt" '̂̂w,is no panacea,"' without seeing ii in action. Moreover, heLÍi.irged, without any basis, that C'liHtenr, a mathematical pro-cedure, could lead to burning down a furnace. My experience isproper deployment of CÜiflrent to operate the HPI would mitigateMicb events''' because ii mandates caretul modeling ofthe financialconsequences of exceeding properly set limits like burning downliirnace.s, so operators would be using better information andmodels to make appropriate .sctpoint decisions for risky tradeoffs.I >etermining .sucb effects rather than ignoring them is the mainidea of science, mathematics and engineering. I refrain from blam-ing MVC^, I'l l), IP. SQC. feed-forward, inferentials, six-sigma,.statistics, talculu.s or tiialhematics for burning down furnact'.s.
I have published practical examples ol using Clifftent to calcu-late APC benefits many times for real applications'"'''''*'"^ '̂̂ *' since[be tow-MiIlur fuel oil example '̂* in HP, December 1996. I bavc.1 library ot commercial oil refmery, olefln, aromatics, polymer,synluels, chemicals and gas processing applications now. Everysingle one is a success because it determines a profit improvement(.sometimes small) and bow to achieve it. I recently sbowed^^ how to(¡uaiitify the value of Friedmans alkylation control approach." '̂'
As for how Cli f f tent works, 1 have published thattoo^"''''^''^*^'*'^^''^* and will repeat it here. Every controlled vari--ible iCV) has a risky profit tradeoff. Calculus and statistics teachintegration ofthe product of a data frequency di.stribution withits associated profit function gives its average (expected value)profit. Repeated integrations witb incremented data means giveihe average profit profile vs. data mean; a smooth hill (for anysianilard deviation >Ü). It's easy to locate the hilltop max profit.md corresponding optimum data mean. Thats how all HI ' lsctpoints, limits, targets and specs are set now, although witb lessrigor. That's also bow C.VIKPi profit meters can be built. ' 1 heHPI received the panacea in 1996."'
A Canadian University ChE Department included deter-mining dynamic system financial performance, ClifTtent, init.s process control course in September 2009. Hopefully thisrekindled academic interest in process control and research onbuilding Clifftent models for integrated alarm management,process maintenance and safety. Once a set of candidate CKs;ind related manipulated variables (Af Ks) are established andI be pracess operation and économies are known, good processcontrol engineering practicc^'^'''''^'^'^'"^^'^'* calls for determiningtbe economic sensitivity of eacb CV, their Clifftents and a vari-,nice reduction claim for each control system design, providingihf appropriate sctpoint determination method and benefit forihat variance reduction. 7 hen the process control engineer is in a•>olid position to design, m;untain and improve the Instruments
and control system, the process operator is in a sound posiiuin touse it and operating company management understands it.s roleand value. They finally have a chemical engineering method foroperation that is pragmatic, prudent and profitable.
ln hct, 1 claim had one or iwo computer-integrated manufaciur-ing (CIM) solution suppliers adopted pcrtormancc-based licensingwhen it was commercialized in the mid-199üs,^"'^'^'*'^^ the land-scape of the APC, and (^IM business in the HPI today would hehealthier, more significant and more profitable lor those suppliersand their operating company partners. And much misguided effortand cxpcase would have heen avoided. fViedman wouid certainly nothe proposing in a 2009 HP editorial forgoing .ÍO'̂ íi of APC '. perfor-mance, worth >$ü.3()/bbl crtide re-fined, to reduce AI'C. maintetiaticecxjsts. It would not he pragmatic, prudent or profitable.
Dr Y. Zak Friedman's HPln Control editorials continue toserve the HPI. 1 hope I can add to them on occasion. W*
LITERATURE CITED
' " l^tour. V. R.. "Why Invesi in PRt}CRSS CONIROL?". CONTROL Vol.XV. x\S. May 2002. pp. 41-46.
''' l^aiiiur. P R., "Why tune control loops? Wby mdte control loops?", ediio-rial guest columnist, Hydrocarbon Processing, V8 I . n9. September 2(102. pp.
'" McMahon.T K., (& P. R. Latour). "CLIFFTENT For Process Optimization."CONTROL V I7 . n l2 . December 2004, p. 66.
' ' l^tdur. P R., "Detisions about risk reduction." l i t ter to Editor, HydrocarhonProcessing, V80. n6, June 2001, p. 3').
^̂ Latoiit. I'. R.. "Quantifying financial values", HP In Control Guest Columnist.Hydrucarhm lhvcrssir,g.V%{i, n7. July 2001. pp. 13-t4.
' ' l j to i i r . P. R., "Align alkybiion separaiiiin to economics." HPln Cx)ntrolliditorial, Hydrociirbiiti Processing, VHS. i i ! , lanuary 2009. p. 98.
'̂' Latour. ['. R.. "Process control: t ' l . l l ' i 'T I ÍN I siiows its more profitable thanex|TecEed," Hydnittirhon froressing, V7'i, n l2 . December 1')%. pp. 7S-H().Repiibliühed in Kane. [.es. VA, Aduamrii Process Control ami InformniionSysifim for the l^ocess ¡ndustrirs. Gulf Piiblisliing, Co. I')')'>. pp. . Í I -37.
'̂' Ldoiir. P. R.. "CLIFHIHNT: Determining I-ull Financial Benefit fromImproved Dynamic Performance." PajierCOI, ih i rJ Intcrnarioual Conferenceon l-dundaiions of C\)mpurer-Aided Process Operations. Snowbird, Utah.)uly "i—IO, l')')8. Proceedings published in AlChK Symposium Series No.320. V94. 1998. pp. 297-302.
^'' Baker. J. A. et ul. "The Rc]X)ri o f l l i e BP U.S. Refineries Independent SafetyReview Panel." January 2007.
^' Friedman, Y. Z., (& G. D. Martin. P R. Latour). "APC Survey," Exchange ofIxiiters to the Fldiior, Hydrocarbon Prficessirig., V85. nlO. Ot toUr 2006. pp.45-46 and V85, n i l . November 2006. pp. 45-52.
'" l^tour. lî R.. "Align Olefin Operations to Lxonomics - Clifiicnt optimizesscipoints." pn-senteil at 2007 Spring AlChF. Meetinj^ Ethylene ProducersConference, Houston. Tex;«, April 2^. 2007. Published in t^onfcrcnceProceedir^s CD.
''' Fricdnian. Y. Z., "Alkylatioti prcKluci separation control," HPIn Conttoleditorial. Hydrocarbon Processing, V87, n9. September 2008, p. 178.
The a u t h o r , president of CLIFFTENT Inc., is an independent conr.ulting chemic.ilengineei specializing in identifying, capturing and sustaining measurable financialvalue from HPI dynamic process control, IT and CIM solutions (CLIFFTENT) usingperformance-based shared risk-shared reward (SR2) technology licensing
HYDROCARBON PROCESSING NOVEMBER 2009 13
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