Canada Weyerhaeuser Kamloops
The Situation
The Weyerhaeuser Company has been producing forest products for the past 105 years. Employing 55,000 people in 18 countries, it is a major player in the forestry, lumber, containerboard, and pulp and paper business throughout the world. Weyerhaeuser currently operates facilities in almost every province in Canada, including their first Canadian purchase in 1964 – a major cellulose fibre mill – located in Kamloops on the Thompson River.
The Kamloops pulp mill currently produces 465,000 tonnes per year of bleached and semi-bleached softwood kraft pulp, mostly destined for Asia, Japan, and Europe. Commitment to forest stewardship, environmental improvement, aboriginal partnerships, community support, and energy efficiency are key aspects of Weyerhaeuser's operations at Kamloops and throughout Canada. Weyerhaeuser Kamloops was one of the first customers to join the Power Smart Partner Program as a commitment to their energy-efficiency policy.
In order for Weyerhaeuser Kamloops to produce steam for its pulp process, it fires boilers with hog-fuel supplied through a chain reclaimer and a large conveying system. The original chain reclaimer was situated at the bottom of a pit. Hog fuel was pushed and shovelled into the pit by a front-end loader continuously throughout the day to ensure that the pit stayed full, but not too full. Three ladder chains at the bottom of the pit forced hog fuel to one end of the pit, before dropping it onto a conveyor. The hog fuel, however, often became plugged and bridged the exit, becoming so compacted that it had to be loosened by air cannons and a cherry picker with a long probe. Whenever the unreliable chain reclaimer broke down or caused the hog fuel to plug up, natural gas was used to supplement the boilers, potentially costing an extra $86,000 (2003 costs) per day. With gas prices increasing, something had to be done.
The Solution
Weyerhaeuser Kamloops considered replacing their chain reclaimer with other types of reclaimers, including a traveling screw or a hydraulic stoker. However, these both suffer from potential plugging and bridging of hog fuel. These systems also operate on the basis of "brute force", which requires excessive amounts of energy. This, in turn, results in high electricity costs, wear and maintenance. So the company looked at another technology – a "moving hole" feeder – a feeder that overcame the other reclaimers' limitations.
Weyerhaeuser Kamloops was already using 12 Kamengo moving hole feeders on their two boiler intakes since as far back as 1992. It was curious to see if the moving hole technology could replace the unreliable chain reclaimer and save electricity at the same time. Weyerhaeuser Kamloops wasimpressed with its current moving holes' reliability and performance, which had allowed the mill to significantly increase energy from wood waste and reduce supplemental fuel requirements. Nevertheless, it was concerned because the moving hole technology had yet to be proven as a hog-fuel reclaimer. To address its concerns, the company decided to replace its chain reclaimer with both a proven screw feeder reclaimer technology, alongside a moving hole feeder, in order to provide redundancy and comparison.
Weyerhaeuser approached BC Hydro and asked for financial support for the moving hole feeder part of their project. This would achieve potential energy savings and offer BC Hydro Power Smart the opportunity for monitoring, as well as to proving this technology as a demonstration project for other facilities throughout British Columbia. Kamengo Technologies provided project engineering and Willis Energy Services completed the project monitoring. A new screw and moving hole feeder were installed in February 2004.
Hog fuel is piled on top of the moving hole feeder hopper by a front-end loader and slowly falls through the holes of the moving hole feeder. The feeder consists of four tables that oscillate slowly back and forth a distance about the same as the width of a single table. A single bar sits on top of each table and sweeps the table as the table moves beneath it. These bars ensure that all of the hog fuel is swept off of the moving hole feeder tables. Hydraulic cylinders, powered by a single 10 HP hydraulic pump, drive the feeder tables back and forth. The hog fuel then falls through the constantly moving holes via gravity onto the main conveyor below. Very little friction exists between the feeder and the stored material, thus avoiding material compaction. As the moving holes traverse the entire pit base, all material is fully discharged.
The Benefits
Since February 2004, the moving hole feeder has proven itself a worry-free and consistent piece of machinery. When delivering 1,000 BDU per day for 355 days per year, the moving hole feeder uses 761 MWh/yr ($25,721/yr) less than the original chain reclaimer and 591MWh/yr ($19,981/yr) less than the new screw feeder. Weyerhaeuser Kamloops has also benefited greatly from improved reliability, uninterrupted feed, increased wood waste utilization, consistent fuel blending, and reduced natural gas usage. Significantly higher "live" storage is now feasible, thus resulting in manpower and equipment savings. At only one day of preventative maintenance required a year, the moving hole feeder has reduced Weyerhaeuser Kamloop's maintenance costs by $57,000 over the chain reclaimer and $27,000 over the screw reclaimer.
The moving hole feeder has been proven outside of the forest product sector with materials such as coal, gypsum, grain, plastic and minerals in manufacturing plants, breweries, granaries, food processors, plastic product manufacturers, mines and bulk loading terminals. Any fibrous material that is prone to clumping, sticking, packing and bridging can be reliably fed out of a variety of storage and feeding configurations including hoppers, metering bins, day bins, silos and reclaims. The mechanical cost of the moving hole feeder is very competitive with other technologies, including belt, vibratory and apron feeders.
Contact Us
Find out how Power Smart can energize your bottom line. Call us today at 604 453-6400 in the Lower Mainland or 1 866 453-6400 elsewhere in B.C.
