DOUG SWEET, P.E.
Process audits in paper mills have existed for years. These can be a “one-man” study with a day or two on site, or heavily staffed events with significant involvement from the corporate level, vendors, and process specialists. Any of these audits require interaction with mill personnel and physical review of process equipment and operating data. Study and analysis cannot be based solely on meetings and presentations of papermaking issues without adequate time for hands-on, eyes-on study of the processes. Also, merely wandering around to look at equipment without involvement from mill personnel will not lead to adequate understanding of system operation under varying conditions.
Regardless, a successful mill audit requires interaction with mill personnel and with information-collecting elements (DCS, instrumentation, trending, etc.). Since early spring of 2020, the coronavirus pandemic has caused a significant and undesirable shift in our ability to manage mill processes when it comes to involving personnel from outside the mill.
Some mills have managed through the disruption better than others. In this article, I’ll offer some best practices and even new practices that I’ve learned from events during 2020.
Our company had two purchase orders for vacuum system reviews/audits set for March and April, 2020, but travel was restricted due to the pandemic. Following discussions with mill personnel, we suggested something unconventional: proceeding without a site visit.
Generally, mills initiate process audits when some issue arises and becomes enough of a concern to cause the mill to request outside expertise. The initial discussion will be a phone call or e-mail, maybe followed with a brief conference call to discuss the situation. Often, the mill team will share some process information prior to me visiting the mill.
The site visit can require 1-3 full days to allow physical observation, study, and analysis of vacuum-dewatering processes and sub-systems. This includes accurate measurements of vacuum levels, vacuum system operating energy, former drive horsepower, etc. Frequently, the study will include trials on the former to retard or enhance dewatering at specific low and high vacuum elements. We’ll conclude the study with an exit meeting with mill management.
Today, we have another option. Where a site visit is not possible (due to the COVID-19 issue, extreme travel time or distances required, or immediate need at the mill that cannot wait until travel is scheduled), we will attempt a “virtual” process study. Experience has shown we can achieve good results even if visiting the mill is impossible.
HOW DO THEY COMPARE?
We’ve developed new processes that adapt to the changes demanded by the current restrictions. Here is how the “virtual” study compares to a traditional, physical site visit:
Step 1—Information Exchange:
• Same as with an on-site study (i.e., we review equipment and process drawings and DCS screen shots; the mill shares forming drainage reports or felt moisture and porosity scan reports).
• Kick-off meeting via phone or web to discuss issues. This should involve process managers, paper machine managers, and reliability managers, same as in a site visit.
• I cannot spend time walking around the process, so mill personnel must be my “eyes.” I’ll send examples of photos and ask them to take similar ones of the mill’s piping and equipment. Experienced troubleshooting will reveal items from these photos that will jump off the screen at me.
Step 2—Examine Data: a few examples:
• Vacuum pump seal water temperature is high. Cooling water is cold… then why is seal water so hot? This was visible in a DCS screen shot (Fig. 1). Mill personnel saw this every day, so the issue had become “normal operation” and didn’t cause concern. The problem was identified as a fouled heat exchanger caused by a bypassed seal water filter.
• In the forming section, aggressive early table dewatering is evident in the DCS screen shot of the table vacuum system. Table drainage reports confirm the problem. The operation had become “normal” for mill staff, and sheet got to the reel. However, this problem causes poor sheet properties and even production limits on some grades.
• Vacuum pump motor loads can be examined and compared with expected power levels.
Overloaded—Why? Can there be an incorrectly operating system or misapplied vacuum equipment?
Underloaded—Why? Is vacuum pump seal water flow being limited, unknowingly, for no reason? Can a vacuum pump be badly worn and in need of overhaul?
Step 3—Analysis and Recommendations:
• Normalization of Deviance—This is the gradual process through which unacceptable practices or standards become acceptable. This is an issue I see in most mills. It is mainly due to loss of talent and knowledge due to retirements and ongoing shrinkage of mill staffs. The first two bullet points in Step 2 are good examples of this. It is a management issue and can be difficult to control; still, it is essential to understand that this unhealthy culture can exist.
• Following a study of mill systems, we will typically discover several opportunities for operational and process improvements, most of which fall into the “low-hanging-fruit” category. Some only require process adjustments. Others require small modifications that can be accomplished during routine shutdowns. A few larger system changes usually require capital but can have significant benefits with good ROIs. Options need to be discussed with mill management.
Step 4—Exit Meeting (via phone or web):
• This is a 1-1.5-hour session involving key mill personnel, during which I’ll present a summary of the study’s findings for discussion. These meetings are essential for good information exchange at the end of the study. “Aha moments” often occur as, together, we examine and explain the issues. Often, some next steps are outlined and plans are made to perform trials and/or make system changes as necessary.
Step 5—Written Report, issued within 2-4 weeks of mill departure.
• The written report is likely followed by an additional phone or web meeting.
• The mill team and I will develop a follow-up list of action items.
• A “Top 5” list is often created to provide some priority of findings and a few easy-to-fix issues.
CAN IT WORK FOR YOUR MILL?
The “virtual” study will not work at all mills. Some mills have poor data collection because of limited DCS capability and/or poor maintenance of instrumentation and transmitters that yield bad data to be collected 24/7. Local instrumentation and gauges must be maintained and must provide accurate information. Many mills have outdated and incorrect system process diagrams, mislabeled equipment, and inaccurate DCS process pages.
For example, it is difficult to troubleshoot a system when you are told that the 2nd suction press vacuum pump is overloading, but the assessment reveals that the 2nd suction press was removed 12 years ago. You discover that the “2nd press vacuum pump” is now the “flatbox vacuum pump” (see Fig. 2). This is a “best practices” tool that includes the need for accurate and up-to-date equipment labeling on DCS screens, physical equipment, and process diagrams.
Mill cultures dictate where good process analysis exists because of high expectations for maintaining equipment and instrumentation. Is there a continuous improvement culture? Is there a search for excellence? There is probably no downside to managing with high expectations, with or without the present health crisis.
As a consultant, I have been working from home since 1983—before it was fashionable, before it was a hip trend, and before the restrictions of the pandemic. This has helped me develop creativity in problem solving, since I can’t simply talk to the person in the office next door or down the hall.
By developing a process for virtual audits, we have been able to continue working and making mill visits without airlines, rental cars, or motels. Our motorhome has been important to allow this. There are always RV parks nearby. We also have taken our instrumentation/gauge business on the road; you can often find my wife, Jacqui, packaging a couple hundred gauges at the picnic table next to the RV. While on the road, she also designs new gauges and fills orders by creating invoices and packing lists while coordinating with another family associate who is handling the physical shipment from the home office.
Following the few virtual studies early in the spring, I participated in a paper machine audit at a large mill where more than 60 people were involved. These audits usually include many people traveling to the mill and being on site from several days to two weeks. I was not at the mill; I was working from home and participated in several web meetings and conference calls during which we discussed issues and made recommendations.
The event was over before I realized that no one had visited the mill during this audit. Our information exchange didn’t make it obvious that no large team was on site. But, for this to have worked well, mill personnel needed to gather a lot of information ahead of time. Also, once the audit began, they needed to assist with getting answers and more data.
The positive point to be made is that the audit was successful without the large, temporary migration of specialists to the mill. Data collection, information-sharing, and communication were all excellent.
Obviously, mills that excel at accurate data collection, good instrumentation, and that have correct and updated DCS process diagrams will always benefit from these best practices. This will be especially useful during our current challenges, which require limited interaction from vendors and specialists. It should continue to be helpful in the future.
While all of our mills are adapting to new procedures, we have an opportunity for positive change. Let’s take what we learn from our personal and work experiences this year to create not a “new normal” but a “better normal” for the coming years.
Doug Sweet, P.E., is president of Doug Sweet & Associates, Inc. in Birmingham, AL. Sweet is a highly experienced engineer specializing in optimization of papermaking processes, especially vacuum-dewatering systems. During a career serving the paper industry that spans more than 40 years, he has visited almost 350 pulp and paper mills in 11 countries. Reach him at [email protected]