Scheduling of Refinery Crude Supply, Operations, Product Blending and Distribution

Check the News Section below for news items.

H/SCHED is a unified approach to scheduling crude supply, refinery operations, product blending, and refinery product distribution. Any one or any combination of these can be provided.

H/SCHED consists of a number of modules which can be assembled and configured to meet the specific scheduling situations of a user.

Every scheduling situation has unique and individual aspects. The H/SCHED approach allows these to be handled from developed software modules and thereby avoid the costs, delays and risks of custom development. Where a new requirement is encounted, it is met by adding small extensions to existing software modules.

The H/SCHED modules can be assembled to have a particular focus which corresponds to the way many companies organize their scheduling responsibilities. These include :

• H/CSS Long Range Crude Supply Scheduling
• H/COSS Crude Supply Scheduling
• H/ROSS Refinery Operations Scheduling
• H/BOSS Product Blending and Scheduling
• H/DARTS Product Distribution via Regional Transportation System

H/SCHED is designed to integrate scheduling with crude data management (H/CAMS) and with planning (GRTMPS). These three provide a single, unified, connected system in which any one or any combination can be used. All can be connected to spreadsheets or external databases such as Access, Oracle, Sybase etc.

H/SCHED is part of OmniSuite which is out integration of Refinery and Crude Planning and Scheduling.

News Section

Short Term Modeling with GRTMPS

GRTMPS is widely used as a planning tool doing monthly and longer range planning. It is excellent for determining the best crudes to buy to meet the best product slate within the flexibility of the refinery.

But the same GRTMPS system can be used to do short term, multi-period modeling (STM). The periods might be weeks or a mixture of periods of different lengths. The model might be set up as four week periods to cover a month. Alternatively, the periods could be 4 days, 4 days and balance of the month, for example. An interesting possibility for a refinery receiving a few major multi-crude cargos per month is to define the periods as the time between crude tanker arrivals.

The point is that you can use the standard GRTMPS system and define your short term model as appropriate for your situation. By using a common data base, the development and support effort is greatly reduced and the application becomes practical and economically.

STM GRTMPS can stand between monthly planning and the powerful, advanced scheduling system, H/SCHED (with its own scheduling optimization and schedule generation).

Just as the same GRTMPS system can be used to optimize both the single refineries models and a multi-refinery model of the refineries, so can the same GRTMPS system be used for a both a monthly model and a multi-period short term model.

Add in the new object oriented, user friendly input and the connectivity to process simulators, GRTMPS is simply the best choice for doing a wide range of refinery optimization situations. If you are not using GRTMPS you are not using the latest and best. (4/14/3)

MUG 36 Conference report

Larry Haverly brought the group up to date with the newest developments in Refinery Scheduling and described some challenging new problems that have been solved. The refinery scheduling team has been expanded to handle new requests and so that multiple working teams can be fielded as required. This is state-of-the-art technology to bring significant optimization benefits in complex scheduling situations.

Dean Trierwiler discussed an example of coupling H/SCHED and H/CAMS to quickly respond to crude oil quality variations. Dean also included remarks about the H/SCHED scheduling system installed at a crude oil public terminal to handle incoming tankers and forward batches by pipelines. (9/26/2)

Refinery scheduling is a Fascinating and Challenging Application

Yet there are so many benefits that it is worth installing the best with schedule optimization and automatic schedule generation.

The latest challenge seemed deceptively simple. A crude unit was run in three modes using different crude mixtures. The reduced crude went to three possible holding tanks. From there two vacuum units were fed. A second crude unit also fed the larger vacuum unit. The smaller vacuum unit made changing amounts of three grades of asphalt (large seasonal demand changes) and at other times paralleled the larger vacuum unit operation. The first crude unit produced reduced crude faster than the smaller vacuum unit could handle so excess had to go into the proper holding tank and the mode changed before the tank overflowed. Because of the holding tanks, the crude unit and the vacuum unit often were operating on different modes.

This turned out to be a very difficult situation to schedule in an optimal way by existing algorithms. It was a complex multi-period sequential optimization problem where sequence of modes and length of periods (different for the crude and vacuum unit) needed to be optimized.

The breakthrough came when the problem was defined as a state changing problem with some use of dynamic programming approaches to optimize. Thirty day schedules could be generated in a few seconds on a PC. It was all in finding the right approach to the solution. This was readily incorporated as a module in our H/SCHED system with all the graphics, simulation and connectivity provided to achieve ease of use for the scheduler. (5/20/2)

Major New H/SCHED Scheduling Installation

We have installed an H/SCHED scheduling system in the world's largest refinery. Operations at over 800,000 barrels per day in five crude units and a preflash unit while running multiple feed modes posed very complex scheduling problems. The standard H/SCHED was extended to achieve handling the special conditions required. These included fragment blending, scheduling of tankers into the harbor during daylight hours, assignment of tankers to buoys or dock, moving tankers among buoys when appropriate, direct unloading from tankers to charge tanks and more. The H/SCHED handles the crude side including deciding buoy and dock assignments, when to move tankers, what tanks to unload into, automatically maintaining optimal segregation in component tanks, when and with what recipe to make crude blends, tracking line fill and more.

The H/SCHED includes our proprietary automatic schedule generation. It generates a 60 day schedule in several minutes and allows the scheduler full control over the details of the final schedule. A wide assortment of graphical user interface features are included. Automatic connections to external data is provided on both the input and output sides. (2/2/2)

Fragment Blending

When you have done many successful refinery scheduling applications, you have seen most of the common instances and developed algorithms to handle them. Fortunately H/SCHED has the flexible framework that lets us cope with the real refinery scheduling situations as we find them. SGM can and does optimize and generate schedules in the wide range of situations found in the individual refineries. Each refinery has posed some challenges to schedule the real operations of that particular refinery.

But sometimes you see something entirely new. We are reporting on this as an interesting blending situation that we have encountered for the first time in one of our newest implementations. We give it the name "Fragment Blending".

Most are familiar with the widely used Header Blending. In this arrangement, feed comes from multiple sources simultaneously, each in the desired proportion. In many modern systems there are automatic controls on the flows, on-line meters of the blend qualities and computer software to adjust the flows to achieve on-specification blends.

Another blending arrangement is Batch Blending. Here one component of the blend at a time is pumped sequentially into the blend tank. Then the blend tank is mixed.

We have handled hybrid situations which combine header and batch blending. In the hybrid situation, because of equipment limitations, part of the time multiple components are fed in through a header and then additional components are added sequentially to finish the blend.

Fragment blending involves a situation where the refinery has a complex piping header. There are multiple connections to the source component tanks, multiple pump combinations and multiple outlets to the various blend tanks. Components can be going through the piping header to multiple destinations blend tanks at the same time but by different paths. Each fragment of the various blends moves through the piping header from a source to a destination by a unique path. The fragment movements can overlap or occur with gaps in time. Automatically scheduling multiple blends to be made in the same time space from multiple component sources while staying within the constraints of the piping header and meeting the requirement for the different quality blends was different and required new algorithms. We were able to solve the problem once we began to treat the various components of the blend as fragments to be scheduled individually, hence the name Fragment Blending. LP was used to decide the best fragments for the final blends. Other algorithms were developed to sequence and schedule the fragments. All in all, a challenging, interesting, different and successful refinery scheduling application. (12/21/01)

Scheduling Optimization II

A Linear Programming model (including MIP when used) can be viewed as a set of possible individual activities with constraints and driving forces.

Constraints take precedence over driving forces. If, in an LP model of a refinery, you fix the amount of a particular crude oil, then the price you enter for that crude has no influence on the optimal solution. If you fix the amount of a product to be made then the price assigned to it is immaterial.

For refinery planning optimization, it is common to use economics as the driving forces (also called objective function). The economics are the costs and prices. Normally, most activities have the possibility of a range of answers and the LP will find the combination that maximizes the objective function (which contain prices and costs) while observing the constraints and is therefore considered feasible.

In refinery scheduling optimization many of the activity amounts of a refinery planning optimization have become fixed. The schedule must work with crudes that are in inventory or in transit and therefore the amounts can not be changed. The schedule must work with specific product liftings that have been committed to and the amounts can not be changed.

Scheduling imposes new goals on the optimization. Planning deals in averages while scheduling deals in time sequencing. LP favors extreme points. A multi-period LP might run a unit at 100% in one period and 0% in the next to average 50%. But refinery operations want a solution which is steady, i.e. 50% in both. The driving forces in scheduling are not simple activity prices and costs but include such things as running steady. Thus the driving forces need to include goal factors in addition to prices and costs where these apply.

The objective of both planning and scheduling is to achieve maximum profits for the refinery. But in scheduling it is necessary to go to the basics and identify what are the choices that will truly achieve the maximum profits. It turns out to be considerably more complex that just running a planning model for shorter periods or doing something like setting up a multiple period model (say by days) and expecting this will be a scheduling optimal.

One need to "think like an LP" but in terms of goals and driving forces and introduce other methodology to supplement the behavior of LP. Thus came our development of the progressional approach to achieve schedule optimization. (10/24/01)

World's Largest Refinery selects H/COSS

SK in Ulsan Korea is the largest refinery in the world running over 800,000 barrels per day of crude. The refinery has very complex crude scheduling problems to keep the five crude units each operating on the proper mode with the optimal crude mixtures. Segregating and storing the crudes which arrive in very large tankers is a challenging matter. So is deciding and making the crude blends which are done using a intricate, multi-path, blending header system.

After a thorough study they selected HSI to use H/SCHED to provide the application system. The system will include the advanced, automatic Schedule Generation capability developed by HSI. The work is under way for delivery by year end. (3/23/01)

Scheduling Optimization(1)

It is well known that a planning LP can be extremely valuable in finding the economic optimal solution for crude selection, market commitments, operating levels of a refinery and similar types of decisions. These decisions are often made one to three months ahead. Also a planning LP is very valuable for making longer range decisions on refinery facilities and long range supply and demand commitments. Our GRTMPS system has been providing such a tool for many years.

Some now are proposing that a planning LP can also be used to provide economic optimization for short term scheduling. However there is a major flaw in that proposal. It is that an LP can only do economic optimization when it can change the amounts of the variables.

If the amounts of various crudes are to be decided, then LP will use the costs of the crudes (and other data) to select the combination with the greatest profit potential. However, if the amounts of crudes are already determined by being in tanks at the refinery or in transit, then the cost of these crude is no longer a factor considered by the LP. If the amounts of individual products to be sold are flexible then the LP will consider the prices in determining the optimal amounts. But when the amounts of products are now lifting commitments then the price is no longer considered by the LP.

Thus as one moves from planning situations to short term scheduling situations, then more and more of the variables become fixed and the ability of the LP to do economic optimization is substantially reduced. Rather the LP becomes a barrel balancer and not an economic optimizer. Of course, it can be a valuable tool as a barrel balancer but claims that it is giving you an economic optimal are greatly exaggerated.

Hence we come to the issue of scheduling optimization. It is different from planning optimization. Both have the goal of maximizing profits for a refinery. But the variables are different and the model and tool must necessarily be different. Considerations such as reducing demurrage, making smooth operations and minimizing risks by avoiding the extreme solutions favored by an LP are examples of considerations that play a role in achieving scheduling optimization.

To achieve true schedule optimization one needs to go beyond expecting a planning LP to work and focus on the variables that are in play in the short term. This is why we developed our progressional approach to scheduling optimization. One has to analyze to identify the variables and then direct these to achieve the overall optimal. (1/22/1)

Scheduling Systems Need OR.

These days it is easy to do a scheduling system which is not very effective. One can create some very nice looking GANTT charts and Inventory Flow charts without a lot of work. However, if it were an auto, there would be nothing much under the hood. The engine would be weak, the ride bumpy and the steering not working well.

It takes more than computer skill to develop an effective scheduling system. It also takes Operation Research (OR) and engineering skills and experience with real applications.

LP is an essential item in planning systems. One can buy an inexpensive LP in a spreadsheet. However this will not serve as an effective refinery planning system. It is the same for effective scheduling systems and any OR specialist will tell you that scheduling is basically a more difficult problem to solve than planning.

It takes a lot of technology to go with a nice look to achieve a useful scheduling system. That combination is what we promise you. We hope you come to us if you want a real scheduling system. (7/27/98)

H/SCHED

We hear confusion regarding scheduling. There are many types of scheduling approaches. We find that crude and refinery scheduling has many aspects different from the run-of-the-mill scheduling applications. For example, the proper handling of live tanks and layering seems unique to our industry.

Our focus has been on crude and refinery scheduling. We have developed the technology to do these properly. Our experience and success that we talk about is exclusively in crude and refinery scheduling and not in unrelated fields. That is why we can offer you so much in support of your needs in these areas.

We can assemble your application from developed modules using three ingredients:

• Great graphics
• Great technology behind the graphics - especially in Schedule Generation where we have a commanding lead.
• The experience and dedication to make the scheduling application work for you.

We take the time and effort to discover your exact needs.  Then we can tailor H/SCHED to your unique requirements.  We support you to ensure you are an effective, happy user. (7/20/98)

H/SCHED and Data Bases

Our H/SCHED scheduling system (and GRTMPS) are designed to connect with any of the usual data base systems to obtain data from and provide data to them. We have developed the generalized interfacing approach and will provide the connection service. H/SCHED will use as much information as is available electronically.

Therefore you can get the world's best in Refinery and Crude Planning and Scheduling tools without regard to the Data Base System you prefer to use or the amount of information currently in that data base. (7/8/98)

Emergency Handled by H/SCHED

A major unit in the refinery of one our H/SCHED user sites came down unexpectedly for ten days. This necessitated a quick shift in operations. It is a critical time with lots at stake. H/SCHED was the tool used to make the corrective response quickly and with confidence and in a way to keep operations as close to optimal as possible.

A really good scheduling tool can have important pay offs. We are here to make a reality of the best in Refinery and Crude supply scheduling for you too. Give us a call.(6/30/98)

New Member H/SCHED team

We welcome Bill Tromans as a new member to the H/SCHED Team. Bill works in the HSE office in England. Many of our clients in Europe and elsewhere already know Bill. Bill has had many years of experience with Haverly Systems and is recognized as having superior skills and background. The team says, "Welcome aboard Bill". Bill is already making major contributions toward our seventh H/SCHED delivery. (6/22/98)

H/SCHED Simulation of Live Tanks

The Denville H/SCHED Development Team has mastered the complex matter of simulating tank tracking of live tanks which are feeding other tanks or operations which themselves may be live. This had been done as needed for specific situations in earlier H/SCHED deliveries. However now it is essentially implemented in reusable code and will be a building block available for assembly of all future H/SCHED systems. We think this H/SCHED technology is a first in the industry. Contact Ken Spencer for details on H/SCHED. (5/27/98)

New H/SCHED Project

HSI has begun a seventh H/SCHED project based upon working from the existing, developed modules of the H/SCHED refinery and crude scheduling system. This will include advanced Scheduling Generation as well as a wide range of other features and is targeted for completion in the fall. (5/19/98)

H/SCHED News

As we support five installed systems and are working on our sixth and seventh new H/SCHED, many advances continue to be made. HSI has special leadership and success in the very challenging area of Automatic Schedule Generation. New proprietary technology has been developed and implemented. Further, HSI now has a comprehensive standard suite of Graphical User Interface options including GANTT, process flows, graphs and other modules. The system is developed as coded and tested modules which can be assembled to meet the unique needs of each site. The Denville office is now the official H/SCHED Development Center for coordinating all aspects of H/SCHED. To learn more about H/SCHED, contact Ken Spencer.

OmniSuite at Sunoco

H/COSS, H/ROSS, and H/BOSS are installed and in routine use at Sunoco.  The three are integreated together and with GRTMPS and H/CAMS.  They are all part of an installed system which truly integrates planning and scheduling.

Crude Oil Scheduling System In Use at Conoco

Conoco is an active, routine user of H/SCHED at two sites since 1996. One site does long range crude procurement scheduling for tankers, multiple pipelines, and barges. The other schedules the crude receipts at the terminal and makes up and delivers over a pipeline the crude blends for three crude units in the refinery. Communication between the sites, which are in different cities, is done over the network electronically.

H/SCHED includes not only extensive graphics and scheduling tools but also does schedule generation.

H/SCHED has been instrumental in aiding operators to achieve smoother operations, provide greater utilization of the crude tankage farm and in providing "what-if" scenarios to the planning and scheduling staff. Schedulers can now reach the optimum solution to problems in an efficient and rapid manner.

One unexpected benefit is a lower than anticipated electricity consumption for transfers of crude from the tank farm to the refinery by scheduling transfers in off peak hours and maximizing the use of transfer pumps. This benefit alone is giving a rapid pay-back which Conoco attributes directly to the H/COSS implementation.

Another notable improvement is in much improved vacuum gasoil/residue separation due to more stable crude blends. H/COSS has assisted in significantly improving control of this separation to the point where the standard deviation of metals content of the vacuum gasoil has improved by 75%.

For more information on the Conoco project, contact us by email.

H/SCHED connection to Access

The Access data base connection is being supplied with the seventh H/SCHED. The connection is automatic and will be used for some special reports and graphics and to provide the user with the ability to do their own custom reports in Access. (7/27/98)

Schedule Generation

We are pleased to report that for our latest scheduling project we have made further extensions to the automatic schedule generation modules of H/SCHED and pushed back the frontiers further. Extensions  integrate the scheduling and blending decisions in H/BOSS II better.

Schedule generation is the most challenging option in our H/SCHED. It is also be quite valuable in scheduling systems involving crude supply, crude receipt and blending, refinery operations, product blending and product distribution. We have developed, and continue to extend the proprietary technology required.

We thank those users who have had the confidence in us to authorize such interesting work and we have worked hard to be sure they get the most advanced scheduling systems in the world and ones with the most advanced schedule generation options. (9/7/98)

Optimum Chronologistic Scheduling

Dr. Martin Fieldhouse has been studying the underlying aspects of scheduling. In his talk at MUG, he points out that ordinary LP models are unlikely to give satisfactory schedules because they result in extreme point solutions.  Real schedules need to consider security, i.e. have some safety margin and buffers for event variations. After considering techniques such as bounding, quadratic optimization, and smoothing first, second and third order differences he proposes a method he names Chronologistic Scheduling.  It is defined as schedules which work out well if events happen as expected but gives as much warning and lead time to reschedule should events not happen as expected.

This gives the type thinking we incorporate in our H/SCHED systems where we include such considerations along with the economics to give Chronologistic schedules. (9/21/98)

Lube Manufacturing Planning and Scheduling

At the recent MUG conference we heard a talk on how HSI software was used to do the planning system for a large lube manufacturing operation. This talk included topics on determining when, how much and in what kettle to do the blends; when, how much and on what lines to do the lube filling and packaging; use of sales and inventory levels to set re-order points; inventory control and many related topics.

HSI has the software which can be used to handle all aspects of lube manufacturing planning and scheduling. This includes both the manufacture of lube stocks and the production, filling and packaging of the finished lube products. Discuss your requirements with us to find out how we can satisfy them with a modern, advanced system. (10/26/98)

NPRA Meeting

HSI will have a booth in the Showcase at the NPRA meeting in San Antonio November 16-18. The showcase will be open Monday 11 - 1:30 and 5 - 7:30 and Tuesday 12 - 2:30. Refreshments will be available in the Showcase area.

This year we will showcase OmniSuite™, our supply chain management solution for integrated planning and scheduling. We will be demonstrating OmniSuite modules including our GRTMPS planning module, our H/CAMS crude assay management module, our H/SCHED scheduling modules, our exciting, new non-linear optimization process simulator interface module GRTMPS-PSI, and our new H/MONITOR plan/actual graphical monitoring module. Ask about OmniSuite support for Relational Database Management System interface links to your information system. These and other OmniSuite solutions will be discussed and demonstrated.

We cordially invite you to stop by and say hello and tell us your immediate or long term problems. We may have just the solution you need. (10/28/98)

Multi-User H/SCHED

Use of a crude or refinery scheduling system typically involves multiple people. From our experience of providing practical H/SCHED scheduling systems in many different environments, we have found that "multi-user" has a variety of meanings. The different users may be in the same office or in entirely different geographical locations. In our latest installation, people in three different cities are involved in creating a schedule, and communication is done electronically over their network to a central database. In the prior installation, all the people were in the same physical office.

Also we find that different sites may be responsible for different parts of the data input. In one of our installations, the long range crude supply schedule was done in one city and the short range crude arrival scheduling was done in another. H/SCHED integrated the information electronically.

Furthermore, different persons may be responsible for different parts of the scheduling. For example, one person may focus on scheduling the crude arrivals, tank assignments and crude blends. Another may focus on scheduling the process units. A third may focus on the product blending and liftings.  H/SCHED handles this too.

Finally, there is a read-only version of the system that may be available in the operations area or manager's office to see but not change the current schedule.

We have worked with all these situations and provided our H/SCHED system with the options to meet the specific needs of different situations. (12/7/98)

Another New H/SCHED Commissioned

We are pleased to undertake delivery of another H/SCHED. The focus of this system will be on the complex matter of gasoline product blending and scheduling. The H/SCHED will include the latest of our advanced Schedule Generation capabilities.

We are excited that more and more refineries are seeing the advantages of our offerings. (2/16/99)

H/SCHED Consolidates Scheduling

A major advantage of H/SCHED for many users is that it consolidates a lot of unconnected spreadsheets into an integrated system. The integrated system has rigorous calculations and automatically connects all the data and maintains it in one system. Being event based, H/SCHED clearly shows all situations where a proposed schedule might lead to a tank runout or overflow, to off-specification stream, to process units operating outside limits, or to other problems. Corrective actions can be taken in a timely way and before there is a crisis. All of this is done rapidly, accurately and consistently by H/SCHED so that the scheduler has time to consider "what-if" alternatives.

Also H/SCHED is invaluable when there are upsets in the plant. It helps adjust the schedule to get the plant back on track toward the monthly plan as quickly as possible.

Further, the use of the unique, advanced schedule generation feature of H/SCHED leads to more profitable schedules.  H/SCHED offers major benefits to refineries still using old fashioned methods. (2/16/99)

Two more H/SCHED projects underway

Haverly Systems, Inc. has received approval to proceed with another H/SCHED delivery. It will include Haverly's Advanced Schedule Generation. HSI looks forward to improving efficiency and profitability at their site.

Another refinery has selected HSI as sole source for an H/SCHED implementation, in recognition that HSI offers the best. This decision will allow the refinery to obtain H/SCHED's advantages more quickly. This H/SCHED also includes HSI's Advanced Schedule Generation. (3/4/99)

H/SCHED can be phased in

Some refineries want to economize and not proceed with a full scheduling system. For them HSI offers H/SCHED without the Advanced Schedule Generation. This allows a phased approach for implementation, in which the refinery installs a working scheduling system that improves operations. Later the full features can be added. HSI's systems are modular so the phased approach is fully feasible and the initial investment would not be lost. (3/4/99)

Transient Schedule Generation

Our H/SCHED system has an advanced schedule generation module (SGM) which seeks an optimal and balanced schedule.

But a further refinement included in SGM is not only the ability to work out the optimal schedule but also the capability to handle the transition from current conditions to that target schedule. The SGM begins with conditions as they exist and schedules through the transition period to the optimal operating situation. The initial situation may not be optimal with tank inventories out of balance, an arrival late, a change in liftings, a process unit down unexpectedly or other problems. But the transient handling features of H/SCHED work to schedule operations back to optimal. (4/8/99)

An Observation

A refinery scheduling system without Advanced Schedule Generation is like an eight year old PC running DOS. Not as effective as it could be. (5/13/99)

Additional Advanced Scheduling Algorithm

Joe Walsh, one of our client schedulers, described a way he staggers crude tank changes to keep the crude feed mixture as constant as possible and the crude distillation unit operating smoothly. We have checked the method out mathematically and find it superior. On the computer it can be made even better than it was by hand because of the use of extra computing power. It is now a part of our H/SCHED Simulator and is being added as a new option in our Advanced Schedule Generation Module.

Thanks Joe. We are really happy when we can combine the skills and experience of our users with our own to achieve synergism and a system that best serves the needs of the users. (5/18/99)

A Refinery Scheduling System - Now or Later, H/SCHED or something less?

If you run 100,000 barrels of crude per day, a state of the art refinery scheduling system like H/SCHED can save you millions of dollars per year. Contact us for more details.

Our users find that the savings come from making optimal, rather than just good choices. They come from handling emergencies and the unexpected better. They come from considering alternatives quicker and with rigor.

With this amount of potential savings, does it pay to delay going ahead? Does it pay to install less than the best? With project payoff just a few month time, shouldn't you have an H/SCHED project under way now? (6/18/99)

Larry will be Moderator for Refinery Scheduling Sessions at NPRA

Larry Haverly will be the moderator for two information exchange sessions on Refinery Scheduling at the upcoming NPRA meeting.

The topic will be; "Scheduling Software for Refineries - The role, challenges and status of software in meeting requirements for optimal scheduling of crude receipts, refinery operations, and product blending."

This is an exciting and timely topic. Larry is expecting lively and productive sessions and invites people to email him comments, questions and suggestions at larryh@haverly.com.

The sessions will start at 2:15 and 3:30 on Tuesday November 16. The conference site is Kansas City. Conference details are at www.npradc.org. (10/14/99)

Refinery Scheduling Breakout Sessions

Two breakout sessions at NPRA on Refinery Scheduling were led by Larry Haverly who was assisted by Victor Haverly. A lot of ground was covered. The place of scheduling between refinery planning and refinery operations was discussed. This leads to the assignment of the responsibility for making specific decisions to the appropriate level. Decisions involving major facility revamps, long term crude supply contracting and market planning are made with long range planning tools (often involving LP). "Monthly" planning can involve multiple months when the crude supply chain is long, when seasonal inventory or plant turnaround planning is involved. The objective is to set a monthly plan to make optimal decisions (most refineries use LP) on what specific crudes to acquire, what product demands can be committed to and generally how to run the refinery on an average, balanced, feasible basis.

Scheduling takes the monthly plan as a goal but deals with the actual conditions in the refinery regarding such things as inventory in tanks, arrivals in transit, liftings committed to, status and condition of process units, etc. Scheduling decisions result in a schedule of the major operating decisions which need to be followed to maintain feasible plant operations. The desire is to also make the decisions which optimize the operations within the scope of the scheduling decisions. [H/SCHED does this] These decisions involve use of specific tanks for arrivals, rundowns, feeds and liftings. It involves specifying key operating variable on process units (such as severity on the reformer), and similar decisions.

Planning makes one set of decisions. Scheduling makes further decisions within the framework of the actual situation and the decisions from planning. Finally Operations makes their decisions to operate the plant within the framework of the scheduling decisions.

Note there is a distribution of decision making. The Integrated Distributed Decision (IDD) form of organization is well suited to carry out the tasks. Todays challenge is to provide the best tools and the integration which make these tasks effective. Computers, networking and software are key elements. Computers and the latest software provide the individual tools. Networking allows fast, accurate information flow. The data passed has to be selected and focused to provide just the right information needed by the decision makers. [In OmniSuite HSI has devoted substantial effort to the question of what information should be passed.]

Some discussion was held regarding the data which should be passed from planning to scheduling. Because of lack of time, discussion on details of the data to be passed electronically from scheduling to operations was only partially covered. The latter would include establishing set points and targets for DCS and where appropriate, the marginal economics for real time optimizers. A discussion was held of providing target recipes and other information to product blend controllers (particularly gasoline).

A survey of scheduling people present indicated that the majority use spreadsheets. Some also use LP for product blending. The newest software will include graphics and simulation. The most advanced are addressing the matter of automatic generation of schedules which are feasible operationally and also optimal. [We are proud that H/SCHED is the world leader in the latter category].

Addition of new scheduling software remains a significant task. However the benefits are large and appear sufficient to make the effort well worth while. Benefits were discussed at the second session and are listed below. (11/18/99)

Benefits of Advanced Scheduling Software

At the NPRA breakout session on Refinery Scheduling the following benefits of better schedule were listed (not in any special order):

1. Increase in throughput without adding facilities.
2. Eliminate crisis actions by better look ahead.
3. Faster, better responses to emergencies.
4. Reduced demurrage.
5. Faster, more accurate scheduling.
6. Achieve schedule optimization.
7. Ability to evaluate special opportunities.
8. Ability to consider what-if possibilities.
9. Reduction in quality give away.
10. Improved product slate.
11. Better sizing of inventories.
12. Use in strategic studies.

These benefits translate into real bottom line improvements. (11/18/99)

H/SCHED at Veba Oel

HSI is actively implementing our proven H/SCHED system at the large refinery complex in Gelsenkirchen Germany. It includes two integrated refinery sites connected by pipelines, three large crude distillation units each operating differently, many processing units, and a major chemical production complex.

The system will include crude arrival and feed mix scheduling, optimization of scheduling for the blocked operations, OUR LATEST IN product blending and scheduling, process unit optimization and scheduling, etc. H/SCHED will include the latest full event scheduling, schedule optimization and automatic schedule generation features. H/SCHED will be integrated with installed data base systems. It will combine with already installed GRTMPS and H/CAMS into an OMNI Suite installation. Delivery will be made in phases for early use of parts of the system with final delivery to be fully integrated. (2/10/00)

Two More H/SCHED Systems Delivered

Two more H/SCHED systems have been delivered, installed and are in use. Both include HSI's unique advanced schedule generation, transient scheduling and optimization. (rev 5/9/00)

Model-Based Reconciliation

H/SCHED is being used to do model-based reconciliation of refinery operating data. This is more advanced than just raw data reconciliation since it considers the specific operating modes and feed mixtures used. It relates expected yields to actual yields under the actual conditions the units were operated (severity, particular feed mixture, etc.).

Some of the benefits include: pinpointing ways to operate better, improving the scheduling model, improving the planning model, quickly identifying bad meters and other plant problems, supplementing traditional static yield accounting methods with more meaningful information.

Standard modules in H/SCHED are used for model-based reconciliation. (6/15/00)

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