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Canadian Forest Products Limited
(Prince George Pulp and Paper Mills), Prince George, BC
Burner Management Systems

Canadian Forest Products Ltd.'s Prince George Pulp and Paper Mill and Intercontinental Pulp Mill are integrated producers of high quality Northern Bleached Kraft Pulp and Paper products. In 1998, the mills produced a combined total of 435,202 tonnes of pulp and 104,582 tonnes of kraft paper.

Universal Dynamics has been involved in the DCS control upgrade of the two mills for the past twelve years. One of the important components of the DCS upgrade that Universal Dynamics has been working on are the Burner Management Systems for the five boilers that Canfor operates at the two mills.

The PG mill has one power boiler and two recovery boilers. The power boiler and #1 recovery are mill original boilers installed when the mill was built in 1965. The #2 recovery boiler was added in 1978. The power boiler and #1 recovery boiler both had relay-based Burner Management systems and the #2 recovery boiler had a card-based hard-wired logic system for its Burner Management System.

The Intercon Mill has a power boiler and one recovery boiler. Both boilers were installed when the mill was built in about 1966 and both had relay based Burner Management systems.

All the BMS systems at the mill were becoming unreliable, they were hard to maintain and troubleshoot and did not give the operators a good indication of what had tripped them out. In 1994, the Intercon recovery boiler was rebuilt as a low odour boiler. At this time, a PLC-based Burner Management System was purchased from a BMS vendor that has since gone bankrupt. Universal Dynamics performed the installation engineering and commissioning services for this project. The PLC program and cabinet supplied by the vendor with this system were not up to the standards that Canfor was accustomed to on their DCS conversion programs, so Canfor hired Universal Dynamics to build the next systems. We worked closely with Canfor to develop logic and PLC cabinet designs to make the BMS system easy to maintain, troubleshoot, and operate.

The systems were based on redundant Allen-Bradley PLC 5/40s tied into a Foxboro DCS system through a KE gateway. A typical system utilizes about 500 I/O points. Graphics screens were developed for the Foxboro system that allow the operators to purge the boilers and open headers. The Power Boiler burners can be started and stopped entirely from the control room with no local operator control other than to change guns to burn different fuels. The recovery boilers require the operators to be on the burner deck when they are starting the burners so Panelview 1000e operator interfaces were provided for each burner deck. The PanelViews give the operator on the burner deck much more information on the boiler status and individual burner status then the old pushbutton and pilot light boxes used to. Over the course of four years, all of Canfor's boilers were converted to this same standard system, including the vendor-supplied system that was installed on Intercon's Recovery boiler.

Click on images to see Recovery Boiler Local PanelView screens:

In conjunction with the BMS systems implemented on the Recovery Boilers, Universal Dynamics revised and implemented a new Emergency Shutdown and Rapid Drain system for each recovery boiler. The Emergency Shutdown (ESP) systems are designed to shut down and drain recovery boilers quickly in the event that water is determined to be entering the boiler. This is an extremely important safety system on a recovery boiler as the explosions caused by water entering the boiler furnace and coming in contact with the molten smelt bed can destroy steam plants with a potential loss of life or at least cause a great deal of equipment damage.

When implementing Burner Management Systems and Emergency Shutdown systems on boilers there are a number of codes and recommendations that must be followed. The systems that Universal Dynamics has built with Canfor are reviewed and approved by Factory Mutual to satisfy the insurance underwriters that these systems are safe and comply with these codes. The codes covered include B.C. Gas Safety Code, Black Liquor Recovery Boiler Advisory Council Recommendations, and various NFPA boiler codes.

These projects were done in conjuction with the overall DCS control upgrades of both steam plants at Canfor, which were done in large part by Universal Dynamics. The result of these projects has provided the mill with improved reliability and increased the throughput of Black Liquor through the recovery boilers. In addition, an auto start feature was implemented on the power boiler that enables burners to start up and stop based on steam demand from the rest of the mill. This has also enabled Canfor to maximize the incineration of hog fuel in the power boilers. This was an important goal for Canfor because it helped them to get rid of beehive burners at their sawmills and to reduce the amount of gas usage in the boilers.

As part of the projects new valves, instrumentation , and piping were installed. The new piping was designed to open up the congested burner decks and allow easier access for the operations and maintenance personnel.

The main Universal Dynamics staff members involved with these projects were Tim Hoy, Nathan Habetler, Alan Martin, and Gord Chilton, though there have been contributions from a large number of other staff over the years.

This type of system can be sold to prospective clients as a package and is an excellent way to for Universal Dynamics to be introduced to other mills. As an example, Universal Dynamics has recently been awarded a fixed price, turnkey, burner management system at Skeena Cellulose in Prince Rupert.