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By Kevin Hogan on October 3 2017
One of the aspects of my job as an Energy Management Co-op at Canfor involves creating employee awareness content about energy savings tips, as well as to highlight some of the completed and ongoing projects happening around the mill. Because of this, I have had the opportunity to learn about many different projects at Northwood, and wanted to share some information about some of the types of projects that have been completed, and how these save energy and are important for the mill.
A Variable Frequency Drive, or VFD, is a drive that controls motor speed by altering the input frequency and voltage to a motor. This allows the motor speed to be matched to the load requirement, as without a VFD, the motor either runs at full speed or not at all. VFD’s are an effective way to save energy and allow for enhanced control of systems which supply flow to a process downstream.
One of the larger projects involving VFD’s at the Northwood Mill was the retrofitting of two pumps, one in the river water pump house, and one in the water treatment facility for incoming mill water. A simplified diagram of the incoming water treatment process is shown below.
Water is pumped in from the Fraser River by six river water pumps. The water then flows to one of two reactivator clarifiers, where coagulant and flocculants chemicals are added, and solids are removed through settling. After this, the water flows to a series of filters. Finally, the now treated water is stored in large tanks, before being pumped to the mill by six mill water pumps.
Before this project was implemented, both the river water and mill water pump systems used recirculation by means of a control valve to achieve flow control. With the installation of the VFD’s, finer flow control is possible, and a significant amount of energy has been saved as the flow can now be matched to the load needed by the mill.
Another project that was implemented at Northwood that involves variable speed drives (VSD) was a new air compressor for mill air. Previously, three air compressors were being used. The third air compressor was being run mostly unloaded, meaning that it was on but was not actually making any compressed air, resulting in unnecessary wear on the compressor and wasted energy. To solve this problem, Northwood installed a fourth air compressor with a VSD. This allows the fourth compressor to remain on standby, resulting in energy savings by avoiding unloaded operation and excessive start up and shut down of the third compressor to meet the air demand of the mill.
There have also been many lighting projects implemented around the mill. These included upgrades in the Bleach Plant, the Machine Room Bale Line, and many more. This resulted in energy savings, as much of the older lamps were inefficient and lost a large portion of the input energy to heat. The new lighting also provides a safer work environment as there is now a larger amount of light in these areas.
In my last blog, I had mentioned the capital project going on here at Northwood to upgrade the energy generation capacity at the mill. On top of this, there are also many other energy saving projects being completed, including heat recovery projects, changing certain mill water services to hot water rather than cold water, as well as addition of flow control to different lines.
Being a part of the pulp and paper industry so far has given me the opportunity to apply what I have learned at school and gain a deeper understanding of chemical engineering in the real world. This also applies for many other disciplines of engineering. For example, my office roommate, who has sadly left to go back to UBC (you will be missed Tristin), is studying environmental engineering, and worked with the Environmental Team for the past year. He had the opportunity to work with air and water pollution control, as well as environmental spill prevention and resource recovery, all important subjects that he has touched on in his program at school. There are a vast array of jobs at the mill that relate to different kinds of engineering, including mechanical, electrical, and process control. All of these positions play important roles for the successful and efficient operation of the mill, and provide continuous opportunities for learning and growth. I encourage other students to consider Canfor as a possible position to complete their co-op work terms, as you not only learn a lot about engineering, but you are also surrounded by professionals that have a wealth of knowledge and are always willing to share and teach others.
As always, I hope you enjoyed the post! Until next time.