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ppendixdditional Opportunityssessment Questions

1 Increase Benefits in all areasa. Do you have loops not running in the highest design mo de(e.g., au to, cascade, superviso ry) because of oscillations, poorcontrol, upsets? Look for impro vem ent by the use of autotuners, gain scheduling, fast reproducible measurements,better loop d esigns, and negligible valve stick-slip.b. Do you have upse ts (bumps) on critical process param etersfrom process interactions? Look for mo del predictive control todecouple and anticipate upsets.c. Do you hav e upsets from cycling back and forth across a splitrange po int? Look for ways to eliminate split range or ma ketransitions sm oother w ith mod el predictive control.d. Do you hav e a tool to define correlations and interactions insystems? Install a performance mo nitoring-system andadva nced data-analysis tools.e. Do you have ba d measurem ents that you can't rely on?Improve measurem ents by using advanced technologies.Calculate batch ave rages an d alert on deviations. (e.g., Don'trely on pH for end po int de tection if curve is different frompreviou s good batches.)f. Do you have areas you can't control because they are ha rd tomeasure? Calculate prop erty estimators from othermeasurem ents and design new control schemes.g. On continuou s processes, do you have ratios installed onrelated flow loops or is everything set individu ally based onmax feed rates? Ratio control can be installed on wastew ater-

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to-feed rate, steam-to-column or reactor-feed rate, additives(soap,oil, anti foam)-to-filter or column-feed rate.h. On set poin t changes, does it take a long time for the variable toreally start to move an d once m oving d oes it go into anovershoot (or unde rshoot)? Use a head start by putting thevalve fully ope n or closed in the beginn ing an d brin g only intocontrol wh en co ming close to the desired set p oint.i. Are you interested in controlling rate of change of a variable(e.g., heat-u p or cooling rates)? If so, don 't try to con trol thevariable itself but u se a RATE calculation for the loo p PV andSP to control the ra te ofrise.The new loop can be used as an

override controller wh ere a signal selector chooses the safestcontroller output.2 Improve yield s

a. In the areas wh ere byp rodu cts are m ad e, can you look for othersequences, other parameters (temperatures, hold times,agitation, etc.)? Com pare p lan t system s to the lab (theoretical)and look for differences. Redesign plant system to match labsituation as close as possible.b. Would mo re accurate end poin t detection imp rove yield orquality? Consider rate-of-change indication of one or moreme asurem ents after a designated b atch time or feed total as anendpoint indicator.c. Do you have sequential batch loads in yo ur reactors? W ouldparallel feed add itions or ratio control impro ve reaction,generate fewer byp rodu cts, imp rove quality and yield, orreduce cycle time?d. Do you run yo ur recovery systems just high enou gh to recover

produ cts at the strengths you need to reuse them? Higherpu rity w ill require more energy a nd create mo re effluent.e. Do you have ma nually set pur ge or vent flows? Look for wa ysto control them an d ratio them to prod uct flows. Calculate andcontrol minimum required p urge or vent rates.

3 Reduce energy and utilitiesa. Are steam, utilities, was te wa ters and b ig mo tors switched offon temporary shutdow ns? Implement systems that will shutoff these systems automatically on tem porary and other

shutdowns.b. Do you run dryer temperatures just high enough with goodcontrols or do you ru n always well above critical w et

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Appendix A Additional Opportunity Assessm ent Questions 411

tem perature? Install better controls (feedforward from feed)and adjust set poin ts for lower energy usag es.c. Cou ld you reduce energy sources (e.g., refrigeration unittemp erature, compressor pressure, boiler pressure) until uservalves reach maximum controllable position? Consider avalve-position controller to optimize use.d. Can you downsize over-designed pu m ps and motors? Can youeliminate flow valves with variable-frequency drive s formotors?

4 Reduce effluenta. Did you think about reusing your waste streams back into yourprocess? Hot water and condensate can be reused for heatingpurposes or as reactor ingredients.b. Can you reuse second w aste wa ters as first wa ste wa ter forfiltering your produ cts? W hen byprod ucts are created can y outhink ab out the cause (e.g., poo r agitation, hot sp ots on h eatingcoils, bad mixing) and adjust controls to reduc e by produ cts?

5 Reduce operating costa. Can you autom ate fieldwork to reduce the m anpo wer ne ededto operate your plant?b. Can you re-schedule your operations better in time so you cansend people to other departm ents or use operators to help onmaintenance during shu tdow n periods?c. Are critical quality and economic variables calculated,analyzed, and indicated online? Give operator information onyields, energy consump tion and production rates, reworkamounts,etc.Make operator aw are to keep operating costs

und er control.6 Reduce maintenance costa. Do you have m aintenance costs du e to poo r operatio n (e.g.,pu m ps cavitating, overloaded, overpressures etc.)? Au toma testartu p procedures an d best operating practices for equipm ent.b. Do you blow rup ture discs and activate relief valves due tom anual disoperation or bad control systems? Use better controland autom ate to reduce safety risk and possible dow n time.c. Cou ld smo other control (reduced therm al and press ure shocks)or tighter control (less byp rod uct a nd co ntamination) increasetime between repairing, replacing or cleaning equipm ent?

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7 Reduce lab costa. Can you install in-line analyzers and control to reduce thenu m ber of lab analyses? It will also reduce cycle time if yo udon 't have to wait for lab results.b. Can you reduce the num ber of lab analyses by improved end -point detections and automation resulting in moreconsistency? Analyze lab results using SPC and adjustfrequency.

8 Improve product qualitya. Can you measure or calculate constraints from existingmea suremen ts? O nce measu rable, it is controllable.b. Ho w close are you run ning to constraints (critical reactiontem perature s, pressures, feed rates, etc.)? Use advan ced controlto ru n closer to or rid e con straints. Switch off reset intoconstraint direction to run closer. Use override controls,feedforward, dead -time compe nsators, valve constraintcontrollers, rate-of-change control, and mo del predictivecontrol to imp rove quality and capacity witho ut violatingconstraints.c. Do you automatically capture pro du ct param eter settingswh en qu ality is good? Use last-run data on star tups to com pareand find ideal settings for each product.

9. Reduce reworka. Do you prod uce rework because the operator som etimesmak es hum an m istakes? Look for autom ation in the areaswhere most mistakes are being mad e.b. Are all you r operating instructions clear, up-to-d ate and easily

accessible? Use uniq ue process param eter d escriptions a ndun its to avoid confusing th e operator at any time.10 Reduce shutdown s and upsets

a. Do you have too ma ny or too few alarms? Is the operatoralerted in advan ce and is he not confused b y too m any alarms?Make alarms smart (e.g., don't wan t Low Flow alarm whenpu m p is stopped). Use advanced alarm handling a nd logging.b. Does the operator have easy access to information w hensomething goes wrong? Can he do his troubleshooting wh en

things fail? Provide help d isplays with dyn am ic informationand instructions on wh at to do to correct.

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Appendix A Additional Opportunity Assessm ent Questions 413

c. Does auto mation level defineIF THENactions to be performedby software w hen something goes wrong? Do not just stop andgive control to the operator.

d. Do you have interlocks shutting you d ow n? Is it easy to trackwh at exactly happe ned ? P ut all the interlocks (soft wired an dcopy hardw ired) into an automation system and providealarms an d dynamic-interlock h elp display s for all interlockconditions. Color display access nu m bers to reflect m od echanges an d interlock condition status.e. Do you have shutdo wn s, upsets, and incidents du e tobyp assing of interlocks? Use interlock-bypass proced ures andindications (forms). Display interlock and byp ass status oncontrol system.f. Do you have buffer tank s in betw een batch and con tinuousprocesses? Smart level control can be u sed to p reven tshu tdow ns in continuou s process by looking at batch cycletimes and smoo thing continuou s feed on batch problem s (seeAp pend ix B).g. Do you hav e a system set u p to track every problem and faultthat generates upsets, rework or shutdowns? Learn frommistakes and set actions to preve nt their happ enin g again. Useproblem reports.h. Can pro duc t changeover (transition) time be reduced?Automate changeover operations (emptying, cleaning, andwash ing). Look for meth ods to reduce transition times an d setoperating parameters for every product.

11 Reduce cycle timea. Can you reduce batch cycle times by eliminating unn ecessary

wa its and introducing parallel sequences (e.g., starting he atingbefore loading , using head starts, combining hold pe riods w ithcooling, etc.)?b. Can you eliminate concurrent actions that slow do w n yourprocess (e.g., blowing cold air in a tank for mixing pu rpo seswhile heating it up)?c. Can you speed up heating times and cooling times by usingenergy more efficiently (colder water, bette r insu lation, be tteragitation, improved burn er performances etc.)?d. Can you prepare premixes in separate tanks in parallel withother sequences, and u se bigger pu m ps , feed lines, and valves?

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e. Is the operator informed and wa rned w hen a system is waitingfor a variable to reach a condition, if the variable do esn't mo vetow ard th at condition (anymore)? If not the system wo uld wa itforever and the operator will find out too late. Configuremultiple dynam ic waits.f. Cou ld yo u detect end poin ts sooner? Consider rate of change orsustained change detection.g. Can you replace weigh ing systems with mass-flow meters?Mass flow can also be calculated for raw ma terials from flow,tem peratu re and pres sure measu rem ents. Coriolis ma ss flow ismo re accurate than load cells and can reduce batch load tim esand cycle times dramatically.h. Can you redesign process param eters and interlock settingsbased on experience from the past? Ada pt settings to processevolution.

12 Avoid costs for other investmentsa. Could autom ation of existing adjustments eliminate the needfor a blend or adjustment tank?b. Can automation and the associated improvement inconsistency of operation reduce the risk for disop eration thatcauses spills and technical incidents?