Energy performance monitoring.pdf

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Energy performance monitoring

For heavy energy consum-ers such as reneries, totalenergy expenses represent

a considerable amount. On theother hand, complex processesrequire a certain minimalamount of energy to guaranteethe desired production output.The question that naturallyarises is how to use the givenenergy in the most efcientway or, in other words, how to

increase energy efciency.There are several approaches

to tackling the vast challenge ofoptimally using energy. One ofthese is the implementation ofan energy management system(EMS) for closely monitoringand increasing energy perform-ance. An EMS can beinterpreted in different ways.Belsims conception of an EMS

is to prepare all process-relatedenergy information so that it isreliable, centralised and easilyreadable, and can be readilyused as support for intelligent

business decisions.This information includes:

Energy performance indica-tors (EPIs) of equipment, singleunits or the whole site Energy balances to determine

A ra ry maam ym ppr mprm arry prfrmac ry cmp a m cr

RobeRt ChARes, heRv Closon a hugues steFAnski BelsimJeAn-ClAude noisieR SIR

accurately the energy consump-tion of equipment and units Monitoring of emissions(CO

2, SO

2, NO

x).

It is measured on a short-term basis (hourly or daily) andis accessible via customisedreporting tools. The results thatare reported through an EMSare key to providing an insightinto process performance,which is the basis for changes

in operating mode to improveeconomic performance.

However, the quality ofbusiness decisions dependsdirectly on the quality of thedata on which the decisions are

based. Therefore, an EMS shouldhave an additional componentthat increases the quality ofmeasurement data. In particular,EPIs are typically calculated

based on other measurements. Ifthose measurements are alreadyfalse, their errors will propagateand amplify. Consider, for exam-ple, an efciency dened as theratio between two quantities, Aand B. If A and B are both erro-neous, it is possible that theefciency would be calculated ashigher than 100%, which isclearly impossible.

Advanced data validationand reconciliation (DVR) is atechnology that uses measure-ment data and processinformation to correct measure-ments as little as necessary sothat all process constraints(such as material and energy

balances or thermodynamicequilibria) are satised, whiletaking into account the uncer-tainty of measurement.

Belsims EMSs always includea DVR component. There aretwo major reasons for thisinclusion: The reported information isreliable and dedicated actionscan be taken to improve energyperformance The impact of the correctiveactions can be seen directly,since energy-related data is

cleared of any noise.In that sense, an EMS can be

viewed as a tool that givescontinuous decision support totackle various energy-relatedchallenges arising in complexsystems, such as reneries,leading to corrective actionsthat have to be taken to amendthem. These challenges could

be, for example, energy imbal-

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ances (fuel, electricity) aroundsome process units or theinexplicably high energyconsumption of some piece ofequipment. They are observa-tions on the process level basedon measurement data.

The results supplied by anEMS:help to truly understandthe process by providingtransparent and reliable energy-related information that reectsthe actual condition of the ren-ery; are presented in atransparent and easily readablemanner; can be exported andused for further analysis; arequickly accessible and updatedfrequently to enable the rightdecision to be made at the righttime.

Based on the results providedby an EMS, dedicated actionscan be initiated at the manage-ment level for example,sensors, equipment and controlsettings can be questioned andcauses of poor efciency can bedetected leading to a repro-duction of better performances.

The impact of these actions canbe veried with the help of anEMS. In order to ensure a

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continuous improvement, thereshould be a frequent interac-tion between the EMS, situatedat the process level, and theactions taken at the manage-ment level. This concept isillustrated in Figure 1.

impma f a eMsThis conception of energyperformance monitoring has

been successfully implementedat Socit Ivoirienne deRafnage (SIR) in Abidjan,Ivory Coast. SIR renes crudeoil to produce various productsfor inland markets and forexport. At the moment, about3.8 million tonnes of crude oilare processed in the reneryeach year. Within the frame-work of a complete revamp ofthe renerys informationsystem (Projet dIntgration delInformation PII), Belsimimplemented an EMS that meetsthe following requirements: Implementation and congu-ration of a completelyintegrated solution that auto-

matically calculates energybalances and EPIs with a highprecision

Accurate monitoring of airemissions for environmentalreporting Energy performance moni-toring of equipment, severalunits and the whole site Gives everybody in the ren-

ery access to the results.The overall objective of theimplementation of the EMSwas to improve the renerysperformance and to make itmore competitive within theWest African area. This objec-tive was to be achieved bycalculating reliable and accu-rate EPIs and mass and energy

balances, leading to animproved monitoring of fuelconsumption, steam usage,electricity consumption andare, and to a decrease in over-all energy consumption.

The solution that was imple-mented at SIR is entirelyintegrated in PII via a third-party integration platform (m:pro) that is the connection pointfor the EMS and all of the othermodules. It links different types

of data and information comingfrom various systems in diverseforms and arriving at differentfrequencies. It includes report-ing facilities that provide therequested information to theright person at the right time.The integration platformcombines different applications,such as renery material

balance, renery unit perform-

ance monitoring, energymanagement of utilities, withdatabases and provides a singleuser interface for engineers fromvarious departments all over therenery.

The EMS automatically fetchesmeasurement data from thedata historian (DAHS), whichretrieves input from the labora-tory information management

Action

Management

ProcessInsight into

processes

Verify corrective

actions

EMS

Challenge

Reporting

DVR

Fr 1 Belsims conception of an EMS


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system (LIMS) and the distrib-uted control system (DCS). Themeasurements can be modied

by manual inputs. The results ofthe EMS are stored on a BelsimSQL database, which can be

accessed through a communica-tion tool on PII by anyone andany application connected to theintegration platform. The inter-connection between the differentcomponents is illustrated inFigure 2.

The EMS is entirely integratedinto PII, and all other applica-tions can access resultsgenerated by the EMS (see

Figure 2). It is also completelyembedded in the daily businessworkow of the end users viathe integration platform toensure a continuous improve-ment in terms of themanagement of energy usage.The end users review the resultsand present them during meet-ings where different businessunits are present.


R acThe project yielded several

benets for SIR. Some of themare described below. More

benets are to be expected assoon as further corrective

actions are undertaken by themanagement of the renery.

ga m a fccyThe integration of the EMS intothe daily workow is the foun-dation of a sustainableimprovement through increasedawareness of energy consump-tion at the renery. Runningthe application takes only a few

minutes every day, whichmeans a signicant gain in timeand efciency: engineers cannow spend time on analysingdata and not waste time oncollecting them.

The ow sheet-based report-ing tools continuously providereliable information on the useof energy at the renery in atransparent manner. Previously,

Integration

platform

Manual

encoding

Oracle

DAHS

Mass

balances

Performance

monitoring ofunits

Production

scheduling

...

LIMS

User interface DCS

Energy

management

Fr 2 Integration of an EMS at SIR

energy balances were estab-lished on a monthly basis notfrequent enough to take actionin due time.

Since it is entirely integratedthrough the integration plat-

form, the whole renery cangain from the informationprovided by the EMS. Forexample, the renery produc-tion balances are establishedpartially based on resultsprovided by the EMS. It turnedout that this helped to calculatethe balances more quickly, witha 50% reduction in time.

Pr f Socit Multinationale deBitumes (SMB) is a companythat is located on the SIR siteand strongly integrated withSIR in terms of energyconsumption among otherlinks. As a consequence of thisenergy integration, SIR sellsSMB fuel gas and fuel oil to beused for treating crude oil for


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estimated fuel consumptionusing raw measurements. Onecan see that an average $60 000of losses could be prevented

per month. This nding aloneensures a return on investmentof less than six months.

ecrcy maac cAn imbalance in the electricitygrid has been identied and

quantied at 2 MW, represent-ing about 10% of total electricityproduction. This imbalancerepresents an accumulatedmonthly value of about$235 000 based on westernEuropean pricing. It is there-fore important to properlyunderstand whether someequipment is consuming moreelectricity than is expected orwhether the difference is dueto measurement errors. As theEMS is based on a data valida-tion and reconciliationtechnology, the electricity

balance is now closed. Table 2ashows SIRs electricity produc-tion on a particular day (14October 2009) and Table 2bshows electricity consumptionon the same day. In both tables,the two columns on the right

indicate the measured andreconciled values respectively.One can see that the electricityconsumption is signicantlyunderestimated and theproduction is slightly overesti-mated, when consideringmeasured values only.

Moreover, the informationprovided by the EMS helped topinpoint erroneous electricity

counters. The imbalance of 2MW was partly due to thecounters at the electricity proc-ess unit substation, which hadnever been calibrated over thepast 30 years. The calibrationof these devices helped toreduce the imbalance in meas-urements to below 1 MW.

Supported by the EMS,further actions will be taken by


the production of road bitumenand by-products. It turned outthat SMBs consumption of fuelhas been systematically under-

estimated by about 215 tonnesof fuel oil equivalent eachmonth. As a result, the averageprice for fuel per tonne ofcrude was underestimated byalmost 20%. This underestima-tion resulted in underchargingfor fuel over recent years. Withthe help of the EMS, the trueenergy consumption of SMBhas been determined with a

higher precision, and losseshave been prevented by invoic-ing the correct amount ofenergy consumed by SMB. Thelosses that were prevented inthe rst six months of 2010 areshown in Figure 3.

Table 1 shows the averagemonthly invoiced amount

based on true fuel consump-tion, as opposed to wrongly

ta 1

u Mar RccGTA5230 11.71 11.25

GTA5240 11.28 11.09

CIE 0.00 0.00

Total 22.98 22.34

ecrcy mpr/prc, MW

u Mar RccP10 3.72 3.91

P11 2.08 2.14

P12 3.75 3.94

P13 8.78 9.82

P14 2.45 2.53

Total 20.78 22.34

ecrcy mpr/cmp,MW

ta 2a

ta 2

im Am, $Jan-Jun 2010 average monthly invoice for SMB, using true energy consumption 321 000Jan-Jun 2010 average monthly invoice for SMB, using underestimated energy consumption 261 000Prevented losses due to energy consumption underestimation 60 000

effc f c f r a rma ry cmp

Fr 3 Prevented losses in fuel invoicing, JanuaryJune 2010


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the renery to close the remain-ing imbalance of the electricitymeasurements, in particular bychecking the accuracy of elec-tricity production. This willhelp to distribute energycorrectly among the process

units in order to accuratelycalculate their effective operat-ing costs.

ga arReneries have are systemsfor burning excess gas. The

burning of some gas might benecessary because it could bedifcult to transport it to otherplaces in the renery, or torelease some pressure for secu-rity reasons. A large amount ofgas being ared indicates non-optimal operation of therenery.

The results of the EMS indi-cate that 2000 tonnes of gas isared each month, correspond-ing to about 24 000 Gcal. Figure4 illustrates the average amountof gas ared per hour on 1March 2010.

This aring of gas amountsto more than $1 million oflosses per month. The EMSdetected and identied oneow meter to the are that issystematically providing wrongdata. Despite this erroneousow meter, the EMS calculatedthe reconciled ow rate to thatare. A team was appointed bythe renerys management to

analyse the possibility ofinstalling a compressor, withthe aim of transforming part ofthe are gas to fuel gas.

em mrEmissions are now monitoredon a more frequent basis, dailyas opposed to monthly, onseveral levels renery-wide,on a unit level and for each


item of equipment and in amore rigorous manner. Theemissions are calculated basedon the consumption of fuel andits sulphur content, which ismeasured four times permonth. Previously, the monthlyaverage of these values had

been used to determine thesulphur content. The EMSalways uses the latest values toprecisely determine emissionsof CO

2, SO

2 and NO

x, which

are then reported directly tothe Ministry of Environment.

The daily availability of thesevalues has been acknowledged

by ISO 14001 auditors.

l arThe implementation of an EMS

based on an advanced DVRtechnology has clearly demon-strated its rst benets. It iscompletely integrated into thedaily workow at the renery

of SIR. It is actively used forproviding continuously reliableenergy-related data. Businessdecisions can now be based ona trustworthy set of informa-tion. SIR has acquiredownership and therefore fullcontrol of the application.Awareness in terms of energyconsumption has been increasedand losses can be prevented

without installing new equip-ment or instrumentation.

The management of SIR hasnoticed a huge time saving inthe collection of reliable infor-mation for both energy balancesand environmental indicatorsas a result of the implementa-tion of this project. The timesaved is available for engineersto analyse in greater depth therenerys current situation andto propose operating improve-ments. In other words, SIR hashighlighted a noticeable

improvement in workingproductivity.

Actions taken by the manage-ment of SIR are steps towardsthe improved competitivenessof the renery. Moreover, theeffects of corrective actions can

be detected more easily andquickly as a result of theremoval of measurement noise

by the DVR technology.

scc facrThere were three importantfactors in the success of thisproject. First, there was a strongcommitment to the project bythe management of SIR and apositive attitude towards themanagement of change. Second,a dedicated, multi-disciplinaryteam was established, formed

600

700

500

400

300

200

100

HSK2 SMB DHC Total

Acid

flare

production,

kg/h

0

Measured

Reconciled

Fr 4 Amount of acid gas ared


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by staff from SIR and Belsim,working together towards thedened objectives. Third, thetransfer of knowledge fromBelsim to SIR was provided bytraining, on-site missions andcontinuous support during the

project and following itscompletion. These factors notonly guaranteed that the projectwas successful for both parties,

but also ensured continuousimprovement after the projectwas completed.

Rr Car is Marketing SolutionEngineer at Belsim, Awans, Belgium,

specialising in energy management and

energy production. He has a masters in

mathematics from Chemnitz University

of Technology, Germany, and a PhD in

applied mathematics from University of

Louvain, Belgium.

Email: [email protected]

hr C is Director, Services andTechnology, at Belsim. He has a masters in

chemical engineering from the Universityof Lige, Belgium, and in management

from HEC, Lige.


Ja-Ca nr is Performance andQuality Manager at SIR in Abidjan, Ivory

Coast. He has a masters in engineering

and a PhD in physics and mathematics

from the French Petroleum Institute, part

of Paris University.


h sfais an Advanced ProcessEngineer at Belsim. He specialises in

energy management, performance

monitoring and production accounting

for downstream applications and has a

masters in chemical engineering from

the University of Lige, Belgium.



links

Mr arc frm fwcar:ery efccy/eryMaamAma & Prc Cr
http://www.digitalrefining.com/article/1000401http://www.digitalrefining.com/articles.html?categoryId=14http://www.digitalrefining.com/articles.html?categoryId=14http://www.digitalrefining.com/articles.html?categoryId=1http://www.digitalrefining.com/articles.html?categoryId=1http://www.digitalrefining.com/articles.html?categoryId=14http://www.digitalrefining.com/articles.html?categoryId=14http://www.digitalrefining.com/article/1000401

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