Using dynamic process simulation for business and risk management; more pulp and paper companies are investing in process simulation to build and operate their mills. The payoff can be substantial.

Managing business risk is a requirement at all levels in an organization. Squeezing more from less while dealing with this uncertainty is the name of the game. The pulp and paper industry consumes enormous amounts of capital. To ensure the continued support of bankers, investors, and insurers, the industry must show that it can design, construct, start up, and operate process plants more effectively and with less business uncertainty. High fidelity, object-oriented simulation where every significant piece of equipment undergoes modeling is a potent tool to achieve this result. The following factors will improve:

* Business concept verification and process design

* Operator training

* Distributed control system (DCS) checkout and startup

* Process optimization 

* Data reconciliation

* Profitability analysis.

The economic incentives are significant as Fig. 1 shows. Moving from a 12 month startup to a six-month startup on a billion dollar project, the savings are US$ 25 million. with the associated simulator costs of US$ 1 million, the return on investment is consider able.

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BUSINESS CONCEPT VERIFICATION AND PROCESS DESIGN

Using process simulation in business concept verification and process design is a reasonably well accepted practice because of the clearly demonstrated results in reducing business and process design risk. For example, CELPAC in Chile wanted to reduce capital cost by eliminating the need for a package boiler by installing a huge steam accumulator. Simulation proved the concept and allowed construction with an accumulator. This saved US$ 30 million in capital cost.

In another example, a simulator creates plant deoxyribonucleic acid (DNA). High fidelity, object-oriented dynamic plant simulation enables much tighter "virtually optimized design" of complex chemical and mechanical processes. This allows improved detail for mechanical, materials, and control design as well as reduced capital cost.

Also, Enbridge, the largest pipeline company in North America, now uses simulation as a tool for optimizing pressure control valve performance.

Equipment suppliers are now using this technology to design production equipment. In the future, equipment "simulation objects" will be available during process design to allow much tighter equipment selection to reduce costs. Andritz, an equipment supplier to the pulp and paper industry, is now using this technology for process and equipment design.

The historical engineering practice of over-design to ensure meeting initial production targets is now obsolete, in the past, designers and engineers were often proud of the tact that they could "tune" a mill over five years to produce 30% more production with little or no additional capital. They had no concern that it took five years--not five months--to reach "true capacity."

COMPETENCY-BASED TRAINING

Unlike the airline industry, the paper industry has expected operators to "fly" complex and expensive machinery with simple book learning, classroom training, and on-the-job-trial-and-error experience. Airlines long ago recognized that they could net afford to have pilots training on planes that did not have revenue-producing passengers on board.

The key issue is that the paper industry also cannot afford to continue this practice. It cannot continue to make "training-based production or quality hiccups" on actual equipment. The industry must realize that a 12 month startup is a very expensive training and learning exercise. It typically represents a 2.5% reduction in project return on investment (ROI).

With sophisticated models and computer enabled and tracked competency-based training techniques, teaching and testing operators is possible. This can ensure that they are truly ready to make from day one--the safest and best business use of sophisticated equipment. The paper industry can also continue to train and test the operators on a continuing basis to maintain their competency. In particular, this can evaluate their ability to respond predictably and correctly to difficult, costly, or dangerous situations. This practice mitigates operating risk.

DCS CHECKOUT AND STARTUP

Equipment today demands complex and sophisticated control that stretches the ability of the best engineers to design, integrate, implement, test, tune, and maintain. This complexity has made it impossible to adequately verify all control actions with traditional means. Control inadequacy is often responsible for expensive failures. Fortunately, new simulation technology enables DCS check-out to prove control efficacy well before project completion. Aracruz in Brazil commissioned a new 700,000 metric tons/year world-class pulp line. This plant was fully simulated in seven operating areas:

* Digester and pressure diffusers

* Oxygen-delignification an screening

* Bleaching

* Chlorine dioxide plant

* Pulp drying

* Evaporation

* Recausticizing and lime reburning.

The simulator helped the project team achieve an exceptional mill startup and then rapidly ramp up to full production. To do this, the simulator examined the role of DCS staging and operator training.

The new line began operations on May 23, 2002, significantly ahead of schedule. The mill startup--from first chips to the digester to the first bale of pulp-proceeded continuously over a period of 45 hours without a single control configuration stoppage. The first significant stop page was mechanical in nature. To date, no downtime has been due to control errors. After four months, Aracruz is 17% ahead of budgeted production.

PROCESS OPTIMIZATION

High fidelity simulation offers a way to optimize and maintain return on capital investment. Once process plants are operational, managers and engineers must continue to find ways to reduce production costs and concurrently improve plant efficiency and product performance. Process simulation can enable this in many different ways, including control loop tuning, simulation of alternative production schedules, and individual equipment performance monitoring.

To do this effectively, the simulator must be able to track information beside that required for mass and energy balances. This becomes apparent when modeling or predicting macroscopic phenomena such as paper quality properties. Leading paper companies have used modern high fidelity process design tools to predict paper stiffness to address customer quality concerns.

Engineering of paper products is now possible to improve their performance and tailor them to business needs of specific customers. Since customers often require those products on a just-in-time basis, the industry can also use model reference control to deal with more grades and associated grade changes. Lastly, the German Paper Institute is now using the same technology to simulate water treatment. Work such as this is providing better understanding of these processes to give improved and more predictable environmental performance.

DATA RECONCILIATION AND PROFITABILITY ANALYSIS

with the plethora of instruments today that provide readings in a largely "inferred" or "highly correlated manner," considerable data results that does not provide accurate and useful business information. with high fidelity process models, developing "corrected data and virtual information" is possible.

The data can be used with confidence for production reporting, maintenance management, and profitability analysis. One can now determine what measurement devices are out of calibration or when a boiler or other piece of production equipment is not delivering the best economic performance. Determining costs for an individual reel of paper is also possible to enable calculating profitability on an order line item.

PROVEN TECHNOLOGY

Dynamic process simulation can improve business performance in the paper industry. Properly applied, it can significantly boost the financial performance of new and existing facilities. For this reason, the paper industry must embrace it as did other industries.

The automotive and airline industries have embraced new optimizing tools to improve returns on capital employed and manage risk. If owners and engineers in the paper industry do not drive use of these tools, customers, bankers, and insurance companies will. S!

IN THIS ARTICLE YOU WILL LEARN:

* How mills can use high fidelity, object oriented simulation on all major equipment.

* Why mills cannot continue to have training-based production or quality "hiccups" on actual equipment.

* How new simulation technology enables DCS check-out to prove control efficacy well before project completion.

ADDITIONAL RESOURCES:

* "Dynamic simulation as a tool far optimizing pressure control valve performance" J. W. Broyles and R. W. Shirt, Proceedings of IPC 2002: International Pipeline Conference, 2002.

* "A case study of the use of actual controls in simulation trainers," M. McGarry, B. Bickell, and G. Pelkey, CPPA, 1997.

* "Aracruz uses a dynamic simulator for control system staging and operator training," A. L. Bogo et al., ABTPC Conference, 2002.

* "Dynamic simulation of retention chemistry effects using a material attribute array structure," R. W. Shirt and M. Manness, TAPPI Engineering/Process and Product Quality Conference, 1999.

About the author: Bill Thomas is director of business systems, forest industry consulting group, for AMEC E&C Services Ltd, (formerly H.A. Simons), Vancouver, British Columbia, Canada. He was with Simons from 1981 to 1993, where he became director of systems engineering and was responsible for integrated millwide and corporate systems. In 1993 he joined BC Hydro as manager, systems planning. In 1995 Thomas joined MB Paper as manager of manufacturing support, a job that included the rollout of a new SAP ERP system. In 1998 he served Port Townsend Paper as director, business systems. In late 2001, he rejoined AMEC. Contact him at: [e-mail]