How cost pressures are changing wet end chemistry.
For this Q & A article, Solutions! magazine spoke with the following paper chemistry experts:
* Kasy King, consultant, Papermaking Process Consulting LLC, Appleton, Wisconsin, USA; and member of Solutions! Editorial Board and the TAPPI Journal Editorial Board.
* Mark Meixner, director business development, Hercules Pulp and Paper Division, Wilmington, Delaware
* Sal Mirza, market manager papermaking technologies, Buckman Laboratories International, Memphis, Tennessee
* Laura Schmitt, product specialist at Nalco, Naperville, Illinois
* Steve Tremont, director, business operations, Ciba Specialty Chemicals, Water & Paper Treatment, Suffolk, Virginia
SOLUTIONS! What do you see as the current status and trends in the development of new wet end chemistry technologies? Are these new developments being driven by the papermaker or the supplier? Which countries or regions are "out front" in these new developments?
KING: As a technical editor for TAPPI JOURNAL and Solutions! magazine, I see a lot of new proposed technology come across my desk. Most of what I encounter is a simple altering of existing technologies: different combinations of existing retention aid packages, modifications of microparticulates that have been around since the 1980s, the same promoters/scavengers we've had for nearly 30 years, moving starch charges up and down, fractionation of molecules to get wider or narrower distributions of structures, slight changes to filler particle shape and distribution, and some effort to make fillers effective over a broader pH range. There has been little if anything on sizing technology. I've seen work with deaerators trying to move out defoamers, but with nothing new in the technology; new bromine biocide systems that are now several years old; and the same synthetic biocides, the same dyes and whiteners, the same dry strength agents, and rosin/alum systems that are still rosin/alum. The old standby--papermaker's alum--is still the same and still works across many different grades.
As an industry, what should we expect when the bottom line is the primary driver that has resulted in the severe reduction in paper company, and supplier research/technical staffs? This "driving out costs at all cost" mentality has led to the overhead of Research and Development being cut to the bone--if not completely eliminated--in all business segments. So, unfortunately, the answer to part of the question is that new developments are not coming from either the companies or the suppliers. Europe and the Far East may be a little bit ahead of the United States in new developments for wet end chemistry, but there is nothing to write home about.
I am also discouraged that the paper schools are not active in the wet end chemistry area for new technology. The Institute of Paper Science and Technology (IPST) used to have some involvement here, but with its merger into Georgia Tech, I suspect that in the near future there will be little or no effort in process chemistry development.
Meixner: With industry capital investment historically not returning the cost of capital, mills are focused on other ways of improving performance. For most mills, the driver for wet end chemistry development continues to be cost. As such, efforts tend to focus on chemistries that improve productivity or reduce raw material costs through the use of lower-cost substitutes or more efficient products.
Another wet end chemistry focus area is in paper grade development. Many paper companies are seeking product differentiation through development of higher value paper grades. Most of these developments are driven by end use markets identified by the paper companies as opportunities for paper and board use. The recent rapid rise in energy costs has also driven investment in technologies that provide energy savings. Much of the development comes from either the Nordic region or the United States; but this is a global business, and technology comes from all over.
MIRZA: As the industry has moved to greater competitive heights, communication has become a critical factor in developing and applying successful technologies. One area that companies must excel in is supplier/papermaker collaborations. Suppliers and papermakers need to work together to develop programs to meet the papermaker's specific runnability and quality problems. These collaborations allow for focus on solving papermaker's problems and in bringing new, proven technology to the marketplace.
A couple of the various areas drawing greatest interest are 1) fiber development: due to the significant swings in energy costs; 2) management and control of stickies, hot melts, and waxes: with the increase in use of recycled fiber; and 3) natural pitch, with new technologies proving effective in the management of pitch, such as enzymatic treatments.
TREMONT: New wet end chemistry developments tend to follow the current economic and legislative status of the paper industry. This dates back to the wet end chemistry "overhauls" during the alkaline conversions of the 1980s, the legislative recycling and deinking mandates of the '90s, and now the focus on consumer needs for long term business survival in the new millennium.
For printing and writing papers, the current development trends are economic and market driven, in that papermakers still envision a cost-effective filler that bonds more like a fiber in order to load up the sheet and improve printing properties. Paperboard producers are focused on manufacturing paperboard with equal strength at lower basis weights, as per "Rule 41" in the North American Free Trade Agreement (NAFTA), which allows for lower weight paperboard that still meets strength requirements.
Papermakers continue to drive developments in meeting consumer needs, especially with competition from non-paper communication media for printing and writing grades, and plastics for packaging grades. Suppliers still support these new developments in wet end chemistry, with legal patents becoming vital for protecting these R & D investments. With the partial or full closure of most paper company R & D sites in North America, look for the long term developments in technology to come from regions where new paper machine building technology is still a priority, such as Scandinavia and Germany.
SOLUTIONS! What is the greatest "need" in wet end chemistry? Is it product or process driven? Are the mills aware of these needs, and if so, are they pushing for their resolution?
KING: The industry makes products to sell to our customers, so it is appropriate that customer needs and thus product needs are the major drivers for process development and improvement. Mills are certainly aware of customer and product needs, but they are less informed as to how wet end chemistry can and does impact these product systems. Much of my career has been spent trying to marry process technologies to product and quality enhancements.
Every wet end additive can and does affect some product and/or quality parameter. Depending on the product type, some of these connections are more important than others, so it becomes very difficult to select one need as the greatest. A good place to start is with the need to educate mill operations and suppliers about the importance of linking wet end chemistry to product quality enhancement and control. These links need to be understood and applied by mill personnel in coordination with suppliers, not merely turned over to suppliers alone. Suppliers are not always tuned into product needs as closely as mill personnel.
MEIXNER: Needs are most identifiable by market segment. In printing and writing, development efforts to increase filler loadings, such as substituting filler-for-fiber, are certainly getting a lot of attention from mills and from Hercules because of the significant cost leverage. In packaging, particularly in Asia, deteriorating supply and increased recycled fiber use are driving the development of strength and contaminant control technologies.
MIRZA: I assume "product driven" to mean from the papermakers' perspectives. Papermakers are continuously pushing the edge with grade development and quality improvements, resulting in paper machines producing grades they were not designed to produce. In a similar manner, papermakers are pushing the paper machines to run faster, sometimes well beyond machine design limitations. This requires flexibility and innovation on behalf of the specialty chemical supplier to provide the appropriate wet end chemistry allowing the papermaker to produce these new grades.
TREMONT: One of the greatest needs is to capitalize on the true synergies between functional and process wet end chemistries, to bridge the gap of technical knowledge with a focused commercial understanding. As the value of water and the cost of water treatment increases, wet end systems become more concentrated, with less fresh water. The functional chemicals that provide the physical properties of paper strength, sizing, opacity, shade, etc. must complement the process chemicals that provide deposit & biological control, retention, drainage, and machine runnability.
To remain competitive and survive in this business, both papermakers and suppliers must drive the need for new functional wet end paper chemicals that meet customer demands for innovative paper and board products. During the design of these new functional additives, thought should be taken on the new additives' effect in the wet end to avoid even more process chemicals being required due to chemical imbalance.
SCHMITT: The greatest need in wet end chemistry is dependent on the goals of the papermaker and the grade of paper produced. Stability of wet end conditions is an important factor in achieving high efficiency of operation and consistent product quality. Once stability is achieved, papermakers can focus on process efficiency and quality optimization rather than chasing unpredictable upsets. We recommend using a mechanical, operational, and chemical approach to balance critical wet-end interactions. This approach uses all tools available in the manufacturing process to optimize operational efficiency and improve finished product performance.
SOLUTIONS! What are the current trends in wet end chemistry monitoring and control--retention, charge, air content, turbidity, freeness, flow measurement, drainage, on-line/off-line, supplier/mill testing, or none at all? What are the strengths and weaknesses in these measurement and control strategies?
KING: Just as in the chemistry discussion above, there has not been a great deal of new development in monitoring and control for the wet end. There have been new generations of older technologies and in general a better acceptance of on-line wet end monitoring instrumentation. Currently there are effective on-line systems for solids content, entrained air, consistency, turbidity, freeness, and charge, as well as the old standbys of pH and conductivity. Flow control for additives is accurate and effective, but the papermaker typically does not focus here, so that systems become out of calibration, frequently resulting in incorrect chemical feed levels. Flow alarms and system interlocks for shut downs are helpful in these areas. There has not been much of a change since the early '80s in the areas monitored or the equipment available. Solids content down the wire (drainage), moisture into the first press, particle size, soluble organics, and starch residual are a few that come to mind as potential areas that would help the papermaker in controlling the process more effectively.
Closed loop control is available on most of the current technologies and is used successfully in a large number of applications. With closed loop control, people should not become complacent about what is going on in the machine room. It is still important for the operators and technical support personnel to walk the floor and observe the process first hand. I am "old school" on this last point, in that I like to see mill personnel involved in wet end chemistry measurement and control. If it is turned over completely to the suppliers, there needs to be some direct linkage for the supplier to benefit from machine uptime and/or product quality.
The best control strategy is where the systems are proactively controlled, the data are collected frequently enough to provide meaningful product related information, and the information is acted on by mill personnel in the proper time frame. Well-run process monitoring systems are continuously reviewed and improved.
MEIXNER: Today, mills have access to more data that are more accurate than in the past. The real issue is how we are taking advantage of this information. Are the data being analyzed properly and used for troubleshooting purposes? Certainly, wet end chemistry monitoring and control is moving to more online measurements as sensor technology improves. The approach provides more real time and continuous process control. This reduces reliance on the supplier for in-mill lab testing. The difficulty is having someone at the mill who understands and can interpret the multitudes of data being generated. It is not uncommon for mills to rely on suppliers to interpret that data. I see mills and chemical suppliers becoming more comfortable with remote monitoring and analysis of these process control parameters, as a more cost effective approach.
MIRZA: Over the past few decades, papermakers have become increasingly knowledgeable about the complexity of the wet end. On-line monitoring of variables such as turbidity, charge demand and conductivity are providing more information about the stock as it approaches the headbox. This knowledge allows for control and management strategies to be in place to offset swings in key parameters that effect runnability and/or quality. On-line measurement of whitewater solids and headbox consistencies provides information regarding what is occurring in the headbox and forming section. Monitoring this information--comparing it to the target numbers--helps troubleshoot the process and bring it quickly back into control.
The next step in this type of instrumentation is on-line control. Once a process has been profiled and baseline data obtained, on-line instrumentation can be controlled to manage the wet end. The goal is to reduce the system variations to a minimum, increasing machine runnability and product quality. The one constant with all on-line instrumentation is the need for a detailed and regular maintenance/service program. Only through this type of attention can the benefits of on-line monitoring or control be attained.
TREMONT: The technologies for wet end process measurement of tray solids, freeness, conductivity, charge, etc. are available and primarily used for system monitoring rather than on-line closed loop control of functional and process wet end chemicals. The new technology on the horizon is on-line predictive control of functional wet end additives for strength, sizing, and optical properties. Linking "soft sensors" with on-line wet end control has been successfully applied at an Australian linerboard mill to predict the highly furnish-dependent Ring Crush Test.
The strengths of applying these on-line monitoring and control systems include the improvement in wet end stability, the more uniform paper properties achieved, and the tools now available to develop new paper grades. A major hurdle is deciding who should pay the bill for the initial installation and the continued service/calibration of the equipment. The debate continues about whether the chemical supplier should be financially responsible for these measurement and control strategies to help market the associated wet end additives, or whether the papermaker should foot the bill to help the mill produce a more efficient product with less downtime and waste.
WHAT YOU WILL LEARN:
* How cost and other factors are shaping wet end chemistry
* Greatest "needs" in the wet end chemistry arena
* The newest directions in wet end chemistry monitoring and control
* "Managing retention, drainage and formation," Alan Rooks, Solutions!, June 2004. To access this article, enter the following Product Code into the search window at www.tappi.org: 04JUNSO40
* "Taking wet end chemistry to the next level," Jan Bottiglieri, Solutions!, June 2003. Product Code: 03JUNSO48.
EDITED BY JAN BOTTIGLIERI, SENIOR EDITOR
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|Title Annotation:||WET END CHEMISTRY|
|Publication:||Solutions - for People, Processes and Paper|
|Date:||Jun 1, 2005|
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