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Process Control: Process Control Benefits and the Bottom Line: How I See It!

Today's global marketplace is continuing to increase the pressure on Forestry Based Corporations to improve their bottom line for their shareholders. The Pulp and Paper Industry must adapt more rapidl...


April 1, 2002
By Pulp & Paper Canada

Topics

Today’s global marketplace is continuing to increase the pressure on Forestry Based Corporations to improve their bottom line for their shareholders. The Pulp and Paper Industry must adapt more rapidly to the new opportunities becoming available to us.

The rate of return on capital employed (ROCE) is low for most companies in Canada. How do we improve the rate on capital employed?

Process control is seen as one of success factors needed for the improvement of ROCE. Process control has the unique benefits of reducing costs and improving product quality simultaneously.

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Today’s situation

“Business is going to change more in the next ten years than it has in the last 50.”- Bill Gates

The start of this new millennium is a challenging one for the pulp and paper industry in Canada and Scandinavia. Today’s industry is facing global competition from low cost, fibre rich players in Latin America and Asia.

In Canada, the return of capital employed for the last few years is typically less than 4% as shown in Figure 1. If we want to keep our shareholders from selling their stake in the pulp and paper industry, then we must improve our profitability.

The general public is pressuring the pulp and paper industry to become more environmentally accountable for its actions. The industry must do its share to meet the Kyoto Agreement on greenhouse gases.

These are some of the concerns that forestry-based corporations are facing today. How does process controls address these concerns which are affecting the bottom line?

Why are we not doing

Performance Monitoring?

The pulp and paper industry is one of the most capital-intensive industries in the world. How do we generate more return on investment from our existing capital?

First we must return to the basics. As a professor once wisely told me in my university days:

“Count the number of bananas going into the building and count the numbers of bananas going out. If the two numbers do not match, go into the building to find the monkey who is eating the bananas.”

In our mills today, we still have hundreds of control loops, which are not functioning to their full expectations. The necessary manpower to daily monitor the performance of a 1000 or so loops is typically not there at the mill level. So we haven’t been counting the bananas too well, and the monkeys are eating our profits!

However, the information age is coming to the rescue to the process control system. With high-speed data historians and with the loop performance monitoring software being developed by PAPRICAN and others, a single engineer can monitor an entire mill daily performance within two hours.

The daily analysis of that engineer allows for preventative maintenance instead of costly unexpected shutdowns due to instrument equipment failure. If you avoid five unexpected shutdowns per year and each shutdown has an average duration of two hours, then you have saved approximately $250,000/year in additional production costs.

The fact that our control loops are not working to their optimum is costing us millions of dollars. Bill Biakowski of Entech has shown that the typical savings generated when process control is properly maintained at Kraft Bleach Plant are approximately $1 million per year. The monkeys that have been eating the bananas are the poorly sized and worn out valves. If the cost is between $150,000 and $200,000 per year to replace and repair these valves for the bleach plant, then why are we not constantly monitoring our process to detect non-performing control loops and repairing these control loops?

Taking advantage

of an untapped resource

In today’s marketplace, retail companies are taking advantage of the data generated from their point of sales devices. They are using this information to develop just in time delivery systems, supply chain management, etc.

In the pulp and paper industry, a typical mill generates over 1000 data points every second. Many mills have data historians collecting these data points every minute or so. What are we doing with this data? The typical response is to look at the data for trouble shooting purposes. Is process data an untapped natural resource? The answer is yes.

Chemometrics can be broadly defined as statistics for chemistry. This area of expertise is being used today in the pharmaceutical, food, cosmetic, petrochemical, and pulp and paper industries. Our industry must be willing to take advantage of our untapped natural resource of data and use chemometric techniques to transform real-time data into timely information which operators, process engineers and managers can use to make rapid decisions to correct problems and optimize their process.

Chemometric techniques such as principal component analysis (PCA) and Partial Least Squares (PLS) provide a new visualization tools to pulp and paper makers. These new tools allow us to see how our processes work together as a system instead of individual parts.

Figure 2 is a simple example to explain this concept. A customer is asking that we provide statistical process control charts to monitor two key paper properties. While these two paper properties on their own are well controlled, they together are not well controlled as a system. If the ellipse is the multivariate control chart 3-sigma control limit, we can easily see that under certain conditions the system does not provide good product.

How does new visualization tools affect the bottom line? Converting tens to hundreds of variables to five or six variables for monitoring purpose speeds up the troubleshooting process. If we can reduce typical mill troubleshooting time from 12 hours to two hours per month, there would be 10 hours of additional prime production available each month.

The 120 hours of additional prime production per year has the potential of generating an additional $600,000 to $1.2 million per year to the bottom line. The cost to implement this technology is the salary of a qualified engineer or specialist trained in chemometric techniques.

These techniques allow us to better understand how our process variables affect the end product quality. We can now transform pulp making and papermaking from an art into a science, when we use other multivariate tools such as design of experiments.

Conclusion

Process control is now a key tool in today’s business environment. From the examples I have discussed, process control has a major impact on the financial bottom line. Process control, when properly implemented, allows us to improve our product quality and reduce our environmental impact while improving our bottom line.P&PC