MEI Brings Extensive Experience to Sawmills Using Steam
MEI has successfully worked with a wide variety of sawmills producing dimensional lumber, shop, specialty, softwood, hardwood. Some plants we work with have low pressure. Others operate at high pressure. Drying schedules vary widely. Some plants had lift in their return, ganged coils, retrofit, new construction. MEI has developed specialized knowledge enabling us to consult with our clients for a best outcome and a quick payback.[/one_half_last]
How to get the most out of your newly converted kiln
Once your steam kilns have been converted to MEI venturis, you will notice more consistent drying. To get the most out of your kiln, consider the following suggestions:
- Sort your wood – by species and moisture content to the degree possible. This will take advantage of the improvement in the bell curve of wets to drys.
- Adjust your Moisture Content (M.C.) – Again take advantage of the tighter bell curve and adjust the target M.C. Many clients report being able to relax the target moisture content and avoid over drying and still have fewer wets to re-dry. This allows a reduction in charge time and saves energy on less re-dry.
- Adjust your boiler set point – Once the plant has been converted, including the header traps and the drip legs, establish optimal production charge times. Once this has been done, experiment with the boiler set point. Incrementally reduce the set point by 5°F at a time and see if you can still maintain great charge times. Once the charge times fall off, back up the set point to the previous setting. The value of doing this is a reduction in vented steam and will show up as savings in fuel, water, and chemicals
More Field Examples
In March of 2004, Boise Cascade converted the kilns at its LaGrande OR facility to venturis. Within the ensuing six months Boise also began converting their sawmills at Kettle Falls, WA and Elgin, OR.
Conversion Date: March 2004
Before conversion: Significant vent, large natural gas fuel bill.
After conversion: Vent settled down. Savings in fuel resulted in a payback of less than six months.
Portac Beaver WA sawmill was converted to venturis in December 2004. Interfor purchased the mill in October of 2008.
Before conversion: Prior to changing to the new venturi system Portac ran a combination of bucket and heat actuated steam traps. They reported rebuilding 6 to 8 traps a month. They had waterlogged coils and inconsistent drying in the kilns. They used 10 to 20 thousand gallons of make-up water per day.
After Conversion: As reported by Ken Welever, Interfor Lead Boiler Man in 2012, the plant experienced a 50% drop in water usage, eliminated cold zones in the kilns and reduced charge times about 10%. No venturis have been replaced to date. Ken recommended a regular blowdown of the Y-strainers to avoid plugging.
F H Stoltze converted all four kilns between April 29 and August 23 in 2005. As they converted the kilns one at a time to the venturis the benefits improved overall.
William Woods, Kiln Supervisor reported, “Your venturi product has been outstanding in performance in our dry kilns. I have operated our kilns for 20 years. We replaced our bucket traps after a lot of research and phone calls from references and mills that have them in operation.”
F H Stoltze report April 3, 2008 after four years of service with venturis:
- With their four zone-controlled kilns they have seen the elimination of wet pockets and more uniform drying.
- They have seen an improvement in drying times as much as 15-20 hours, depending on wood species.
- They have more control over the kilns and the boilers don’t struggle to keep up with the kiln steam demand.
- Kilns warm up faster and the kiln schedules are not as harsh as they were.
- Their lumber now looks great and has less degrade, tighter moisture content and standard deviation.
- Their grade inspector is very pleased with their lumber.
William Woods, “It was a pleasure to work with your field technician to make sure everything is working properly, your company made the necessary changes to our system to make it function and get the most efficiency. Thank you for your concerns and improvements you have made at our plant, I would recommend this to any plant for replacement.”
JELD-WEN converted all 13 of their kilns in their Bend OR plant to venturis by the end of December, 2005. These venturis are often called orifices because they have a fixed orifice.
Client reported on June 28th, 2006:
All orifices [venturis] were installed and all kilns operating.
Before conversion: They had numerous kilns with mechanical traps that were failing. The traps were installed in locations inside the kilns making them almost impossible to troubleshoot and maintain. They were constantly having to extend kiln schedules due to insufficient kiln temperature due to trap failure.
After conversion to venturis: These problems disappeared. They have had a solid six months of operation with all 13 kilns without a single related occurrence.
Dan Larwin, “I look forward to the continued performance for many more years.”