Refinery Flow End-to-End Refinery Scheduling · of crude scheduling, process unit scheduling, crude and product blend optimization, product pro-gression and product lifting. SIMTO

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Scheduling systems play a vitalrole in process industry’s supply chain. The scheduling deci-

sions involve many competing fac-tors such as: achieving economictargets and handling environmentalregulations, meeting quality re-quirements and reducing qualitygiveaway, supplying adequate feed-stock and reducing feedstock inven-tories, responding to operation dis-turbances and maintaining opera-tion safety. Scheduling a site is acomplex and multi-dimensionaltask, requiring the coordination ofmany schedulers and operators.

Planners and schedulers needto visualize the plant level operationand drill down as required to seethe cascading effect of crudechanges and quickly run what-ifscenarios to evaluate alternativeschedules. The advanced technolo-gy provides simultaneous executionof crude scheduling, process unitscheduling, crude and productblend optimization, product pro-gression and product lifting.

SIMTO systems represent thenew technology trend for process

End-to-End Refinery Schedulingindustry’s scheduling systems –visualization and optimization. Visu-alization technology provides theright tool for schedulers to identifythe scheduling problems and inter-actively solve the problems. Optimi-zation technology helps the sched-uler achieve maximum profitabilityand find feasible solutions on short-term and long-term schedules.

SIMTO Refinery SolutionOverviewThis paper describes howM3TECH’s Refinery Schedulingsolution can be applied to a worldclass refinery.

The SIMTO Refinery Solution isan integrated solution for planningand scheduling management inrefineries. The solution covers refin-ery activities from feedstock toproducts, from receiving to ship-ping, from corporate to plant plan-ning, and from internal to externalscheduling:• Summarizing multi-site schedule

data across the supply chain tocommunicate among enterprise

applications and to share withtraders, managers, and enterprisepersonnel.

• Planning activities across the enter-prise on a single user-interface tointegrate data from multiple sourc-es, improve data comprehension,and increase outcome visibility.

• Scheduling feedstock receipts,processing unit operations, andproduct shipments to improveasset utilization.

• Optimizing blends of feedstockand products for multiple periodsto comply with equipment limita-tions, improve yields, meet quali-ty specifications, and deliver prod-ucts on schedule.

• Scheduling receiving and ship-ping docks or terminals with con-siderations for constraints inweather, traffic, vessels, berths,and inventories.

• Integrating planning and schedul-ing activities in an enterprise so-lution to facilitate communicationand enhance coordination andcooperation.

The SIMTO Refinery Solution iscomprehensive but user-friendly. All

Refinery Flow

By : Robert Hutchings, Dr. Dong Dong, Nam Nguyen, M3 Technology Inc., SIMTOTM Refining, US

I OIL AND GAS I ENGINEERING I

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the pieces of the solution workseamlessly together to streamlinebusiness processes and minimizehuman error.

M3 Technology’s refinery solu-tion incorporates innovative applica-tions in business intelligence, plan-ning, scheduling, and optimization.Production plans provide refinerieswith guidelines comprised ofmonthly averages, but refineriesneed efficient schedules to makethose plans a reality. M3’s refinerysolution has applications thatschedule plant activities, optimizeblending, and manage dock or ter-minal operation.

SIMTO™ SchedulingSIMTO Scheduling provides a flexi-ble scheduling platform combinedwith a comprehensive modeling toolthat is functionally powerful, simpleto use, easy to maintain, and easy tointegrate with other systems.

Schedulers need to know theusable capacity of a plant to sched-ule feasible production. This capaci-ty is hidden in the constraints andinterdependencies of the plant’sfacilities. SIMTO Scheduling simpli-fies these complexities with graphi-cal representations or flowsheets ofproduction processes. Modelinginvolves drawing icons and settingtheir parameters on window-basedforms. Relationships among facili-ties like tanks and processing unitsare determined by logic units andoperation modes. The current plantcapacity is represented by a base-line, a set of values including tankinventories, qualities, unit yields,blend compositions, and line fills.From a baseline, schedulers arrangesequences of operational activitiesto meet near-term deliveries.

With the model handling thecomplexities of the production pro-cess, schedulers are free to focus

on scheduling. SIMTO Schedulinggives schedulers the flexibility tomanage operational activities andstill observe the plant’s usable ca-pacity by enforcing dependenciesand constraints. Schedulers assignactivities such as feedstock re-ceipts, tank or pipeline transfers,unit operations and status changes,blending, and product shipments bycreating bars on a Gantt chart andediting their parameters on a win-dow-based form. These activitiescan be serial or parallel and linkedor unlinked. SIMTO Scheduling’suser-friendly interfaces and custom-izable Gantt charts make schedulersmore efficient and support betterdecision making.

Schedulers receive instantfeedback about inventories, productqualities, and constraint violationsafter scheduling changes so thatschedulers can monitor the perfor-mance of schedules. At any given

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time, SIMTO Scheduling’s simulationengine predicts raw materials inven-tories and qualities, productionrates, unit yields, and product quanti-ties and qualities, while enforcinginterdependencies and constraintsdefined by the model. Configurabletabular displays and trend chartshelp schedulers monitor changes ininventories and qualities. Violationicons warn schedulers about tankoverflow or underflow. Schedulerscan identify time gaps on Ganttcharts for possible demurrages andshipment delays. Schedulers can dowhat-if analyses to compare the per-formances of different schedulingscenarios so that schedulers canmanage inventory effectively anddevelop feasible and profitable pro-duction schedules.

SIMTO™ M-BlendPart of scheduling is to ensure thatthe right crude mix is processedand the right product is shipped. M-Blend (Multi Period Blend Optimiza-tion) is a comprehensive, flexible,and versatile solution for blending,which is a common activity in refin-eries and has strong economic andoperational impacts.

M-Blend solves the blend opti-mization problems involving multi-ple products and multiple periods inrefineries. This optimizer finds theoptimal recipes that meet the speci-fications of individual blends acrossthe schedule horizon, while mini-mizing the cost and quality give-away and honoring the constraintsof material balances, logistics, andshipments. Materials are distributedwithin the minimum and maximumlimits of material pool and compo-nent compositions. Logistic consid-erations ensure that tanks servicethe right materials, follow the prop-er switching sequences, do notoverflow or underflow and aretransferred within pumping capabili-ties. Products will be shipped at theright volumes and on schedule.

M-Blend accommodates flexi-ble objectives and breaks infeasibili-

ty. While searching for the optimalrecipes, the optimizer may enforceor relax the requirements to meetspecifications, depending on theuser-assigned penalty factors forthose specifications. The optimizermay try to meet the exact specifica-tions for the user-specified, imme-diate future of the schedule andloosen the specification limits forthe distant future. When flexibilityfails to produce optimal results, theoptimizer specifies the volumes ofmaterials required to break the in-feasible problem.

M-Blend tracks the qualities ofblend products and tank inventoriesduring the optimization search. Theoptimizer blends properties, usingavailable blending methods such asindexes, biases, property bonuses,interactions, formulas, and nonlin-ear correlations. These blendingmethods are versatile and adaptableto a wide range of blending applica-tions including reformulated gaso-line (RFG), diesel, naphtha, fuel oil,crude oil, and asphalt.

SIMTO™ M-Blend forCrude Oil BlendingRefineries must minimize crudecost while meeting production re-quirements. Quickly and accuratelydetermining crude recipes for thecoming week, month or any periodwith SIMTO refinery solution allowsthe crude scheduler to see the cas-cading effects of crude blendingand schedule changes.

M-Blend is a comprehensiveblending tool that helps the crudescheduler deal with the complexconstraints in specifications, inven-tory, logistics, and productionschedules. Key capabilities of theapplication are:• Stabilizing crude feed qualities

and using more economicalcrudes by optimizing crude blend-ing to meet quality specifications

• Minimizing the total cost of multi-ple blends of crude oil over multi-ple periods in the schedule hori-zon, while honoring constraints in

specifications, inventory, logis-tics, and production schedules.

• Avoiding the problem of optimiz-ing a single blend at the risk ofinventory shortage and unit shut-down or slowdown for subse-quent blends of the crude mix.

• Managing inventory economicallyby accurately predicting demandsof crude oil components. Invento-ry control is important with thetight supply of crude oil.

• Controlling critical properties thatlimit the amount of crude mix canbe processed. For example, sulfurand vacuum resid contents havemaximum targets because of thebattery limits of the sulfur recov-ery and coking units. A crude mixwith a high total acid number maybe incompatible with the metallur-gy of the processing units. Hydro-gen availability and hydrocrackingcapability determine how heavy acrude mix can be processed.

• Predicting blend properties accu-rately with versatile blendingmethods including linear blend-ing, bonuses, formulas, interac-tions, and dynamic libraries. Thelibrary blending method can han-dle complex correlations of oilcompatibility models to predictasphaltene insolubility to preventoil separation and heater fouling.

• Blending the crude mix consis-tently for stable operation andconsistent product quality.

• Increasing refinery flexibility withthe ability to blend crude oils out-side experience and to adaptquickly to changes in crude sup-ply and quality.

• Managing product specificationsand blending methods through ablend knowledge base.

SIMTO™ M-Blend forGasoline BlendingGasoline blending contributes animportant portion to the profit mar-gins of fuel refineries. Fluctuationsin costs and qualities of blendstocks and stringent quality specifi-cations and regulatory requirements

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of gasoline products increase pres-sure on refineries to minimize costand quality giveaway. SIMTO M-Blend for Gasoline Blending canhelp refineries optimize gasolineblending and manage the complexi-ties of this process. Key capabilitiesof this application are:• Minimizing cost and quality give-

away of multiple blends over mul-tiple periods in the schedule hori-zon, while honoring constraints inspecifications, materials, logis-tics, and shipments.

• Providing standard and custom-able blending library such as RFG,CARB, and Distillate and solvingnonlinear blending optimizationproblem.

• Avoiding the problem of optimiz-ing a single blend at the risk ofinventory shortage, shipmentdelay, and even loss of sale forsubsequent blend products.

• Managing inventory economicallyby accurately predicting demandsof blend stocks. Inventory controlis important when the availabilityof qualified blend stocks decreas-

es with stringent regulated proper-ties such as sulfur, NOx, and VOC.

• Predicting blend properties accu-rately with versatile blendingmethods including linear blend-ing, bonuses, formulas, interac-tions, and dynamic libraries. Theinteraction and library blendingmethods can handle complexcorrelations in calculating gaso-line properties such as RON,MON, NOx, and VOC.

• Increasing market flexibility withthe ability to blend stocks outsideexperience and to adapt quicklyto changes in inventory and prod-uct requirements.

• Transitioning efficiently from gradeto grade, season to season, andeven area to area. For example, themulti-blend, multi-period optimiza-tion balances between blend downand draw down for the transitionfrom winter fuel to summer fuel.

• Managing product specificationsand blending methods through ablend knowledge base.

• Tracking material usage and regu-lated properties to comply with

regulations such as anti-dumpingand environmental protection laws.

SIMTO™ Dock ManagerRefineries receive feedstock forprocessing and ship products tocustomers. Scheduling receipts andshipments of large feedstock orproduct cargoes at refineries is chal-lenging with constraints involvingweather, channel traffic, vessels,dock facilities, terminal inventoryand sendout rates, and contractualobligations. Dock Manager consid-ers all these constraints and auto-matically generates an optimalschedule and a report listing thescheduled time of each step forevery cargo and provides an over-view of demurrage and delays.

SIMTO Dock Manager is an inte-gral feature of the SIMTO Schedul-ing system. Dock Manager automat-ically schedules the ships at a dock.The system considers many factorswhich may impact the terminal op-eration including berth/jetty con-straints, traffic congestion, weatherconditions, terminal inventory, ter-

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minal send out rates, contractuallimit, cargo arrival schedule andfacility maintenance. SIMTO DockManager provides the ability to visu-alize the future and to generate aschedule for the cargos arriving atthe jetty or berths.

The automatic scheduling tech-nology addresses major activities atthe dock such as:• Automatical ly choose docks/

berths.• Automatically assign receiving

tanks• Automatically check for constraint

violations before inbound andoutbound transits

• Automatically calculate delaysSIMTO Dock Manager facilitates

inventory management and reducescosts by minimizing demurrageacross feasible schedules while con-sidering active constraints includingthe berth or jetty and channel traffic.

Scenario EvaluationM3’s refinery solution’s power isevident in its ability torapidly explore andanalyze what-if scenari-os to provide refinerypersonnel such as plantmanagers, crude trad-ers and plant operators,with information tomake fast and accuratedecisions. For example:• A refinery manager

may ask what planthe refinery shouldfollow to meet itsgoal when demandsfor certain productshave changed.

• A crude trader mayask what crude oilshould be purchased,how the new crudefits in with the exist-ing crude mix, andwhether it is compat-ible with processingunits.

• A refinery schedulermay ask what inven-

tory levels in crude tanks shouldbe maintained to reduce demur-rage costs due to unloading de-lays and to prevent unit shutdownor slowdown due to low feedsupply or when certain productsshould be blended to prevent lateshipments.

• A unit engineer may ask what theimpacts on downstream units arewhen a unit is taken off-line.

• A plant operator may ask howclose to the operational limits aprocessing unit should run with anew feedstock.

• A shipper may ask which vesselshould be docked first and if it fitsin the first available berth.

M3’s refinery solution can simu-late these scenarios and providerefinery personnel with qualitativeand quantitative information tomake time-constraint decisions.

Enterprise SolutionM3’s refinery solution provides auniform view to the enterprise

through user-friendly interfaces,visualization of results, multi-userand multi-site operation, and dataintegration.

Multi-user and Multi-site Oper-ation – SIMTO applications makecommunication easy by allowingmulti-user and multi-site operation.Users can be assigned to one ofthe following roles: administrator,nominator, scheduler, and viewer.Depending on their roles, someusers can make and save changesto all or certain parts of the sched-uling system, but all users canview the schedule and do what-ifanalysis. The enterprise architec-ture of SIMTO applications im-proves communication and pro-motes coordination and coopera-tion among groups within an orga-nization.

SIMTO™ Integration Depot andWeb Services – Data integration isanother factor in improving commu-nication. Integration Depot providesimporting and exporting abilities to

transfer data amongSIMTO Product Family.Integration Depot,along with Web Ser-vices also facilitatesinterfacing betweenthe Product Familyand external systemssuch as planning sys-tems, ERP, accountingsystems, lab informa-tion systems, processcontrol systems, andreal-time movementtracking systems. Theapplications in Refin-ery Solution aresmoothly integratedwith corporation net-work security sys-tems because theywere developed withMicrosoft .NET tech-nology to producepure managed codeapplications for se-cure internet/intranetdeployment.

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Operational BenefitsThe scheduling applications of M3’srefinery solution can help a refinerynot only improve its promises tocustomers and shareholders but alsoachieve safe and sound operation bypredicting the outcomes against allthe constraints in the model. Theimpacts of any change in weather,feedstock, or product quantities andspecifications can be simulated bySIMTO Scheduling, SIMTO M-Blend,and SIMTO Dock Manager.

SIMTO Scheduling can save therefinery money by tracking feed-stock inventories. It tells schedulersthe exact time window in the nearfuture to bring in a certain feed-stock. Tank underflow and demur-rage can be significantly reduced.

SIMTO Scheduling’s inventoryplanning board can improve invento-ry management and prevent incidentssuch as unit shutdown, tank overflow,tank underflow, and late shipment.

SIMTO Scheduling can also helpthe refinery plan for the long-term.Refinery traders can decide when tobuy and sell certain materials and inwhat approximate amounts. SIMTOScheduling gives a refinery the abili-ty to evaluate a new or price-advan-taged feedstock available in themarket and to determine its com-patibility with existing feedstockand processing units. Along with M-Blend, a refinery can save moneythrough feedstock blending to pro-vide the optimal feed qualities forthe processing units.

SIMTO Scheduling gives usersthe flexibility to simulate the wholeplant or just one processing unit.Users can easily change operatingparameters through an interfacewindow to evaluate the impact ofdifferent operating conditions be-fore applying the selected conditionto the real world production.

SIMTO Scheduling providesusers the ability to prepare for andadapt to daily supply changes.

Dock Manager automatically ad-justs docking schedule according toweather conditions to avoid traffic con-

gestion and to direct inbound and out-bound vessels to the right berths forsafe docking, loading, and unloading.

SummaryM3’s refinery solution provides aworld class refinery with an inte-grated system to help plan andschedule productions that meetcustomers’ demands and increaseshareholders’ return on invest-ments. The solution is comprehen-sive and extensible. SIMTO Schedul-ing simplifies scheduling with flow-sheets to model manufacturingprocesses, Gantt charts to arrangeoperational activities, and case com-parisons to evaluate various opera-tional scenarios. SIMTO Scheduling

solution will help a world class re-finery make difficult and time-con-strained decisions regarding un-precedented changes in feedstockand additive costs. SIMTO Schedul-ing simulates the impact of feed-stock quality and compositionchanges on product yields. M-Blendoptimizes multiple blends over mul-tiple periods to minimize costs andquality giveaway. Dock Managerautomatically schedules cargo re-ceipts and shipments within con-straints from weather to terminalinventory. These applications worktogether seamlessly and communi-cate with other systems throughSIMTO Integration Depot and WebServices.

Robert Hutchings has 30 years experience in the oil & gasand petrochemical sectors with 10 years working in TexasGulf Coast oil refinery. Bob has extensive experience in upperlevel sales, marketing and consulting roles for majorcomputer integrated manufacturing and supply chainmanagement software companies. Bob has worked as leadengineer and project manager on U.S. domestic and globalprojects including Russia, Korea, Japan, Czech Republic, Saudi Arabia, Chinaand many more. Bob has a BS Degree, University of Tennessee in ChemicalEngineering and a Master’s in Business Administration, University of Phoenix.

Dr. Dong Dong has 18 years of experience of research,development and service in process automation, productoptimization and information integration applications forprocess industries. Dong founded M3 Technology in 2002and he has instituted a clear vision that has guided M3 tobecome a leading provider of planning, scheduling, multi-period blend optimization and distribution systems andsolutions for both the plant and enterprise level. Dong has extensive industryexperience, including acting as a Senior Consultant and Team Lead and projectmanager at Aspen Technology. Dong has a B.S. degree in Electrical Engineeringfrom Tsinghua University, a Masters in Process Control from TsinghuaUniversity, and PhD in Chemical Engineering from the University of Maryland.

Nam Nguyen has 18 years experience in oil refining industry.He is the lead engineer in rolling out the SIMTO refinerysolution to Tesoro Corporation, a leading independent refinerwith 7 refineries. Nam has worked as senior engineer intechnical teams to support joint ventures and supply chainof several refineries in the Texas Gulf Coast. Nam hasextensive experience working for Pennzoil – Quaker Statewhere his duties included conducting pilot plant tests and providing technicalexpertise to support refineries and process development. Nam hasexperience in catalyst, feedstock, and crude oil evaluations and is skilled atinterpreting process data and developing models and correlations. Nam hasa B.S. in Chemical Engineering from the University of Houston.

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