In August 2006 Epsilon Solutions contacted Primasonics® International regarding a problem that was being experienced by their customer, Claymark; a manufacturer of timber doors & associated products for domestic & export markets. This enquiry was passed on to their Australian Agent; Bulk Materials Handling to attend.
Assessment of the Problem
The problem was essentially the fouling of the wood waste-fired boiler that was used to supply hot water to timber drying kilns. Increasing production meant higher volumes of wood waste & shavings being burnt which reduced the cleaning time from every six weeks to every ten days. This was having a major effect on drying schedules as the plant has to be shut down for ten hours per week as well as loss of efficiency of the boiler during operation. This reduction equated to 7Mw MCR (Maximum Continuous Rating) to 4.5 Mw.
Brendon Stephenson supplied BMH with drawings of the boiler & this was then
discussed with Primasonics & two PAS-230 units were recommended for the application.
The units were supplied under a trial agreement. The agreement stipulated that the units provide a reasonable payback & not ad deleterious environmental factors by way of noise.
Installation & Commissioning
The two units (PAS-230’s) were installed & commissioned late February, 2007 & were inspected by Graeme Gardiner of BMH at the commissioning stage.
The Claymark plant is in a rural area, however, noise restrictions only allow a level of 60 dBA at the property boundary 500 metres from the boiler. Initial testing showed 62dBA during the day at that point. The noise allowances fell to 40dBa at night. It was also 84dBa adjacent to the boilers. More work was required to meet those restrictions & continue trial.
The units were enclosed reducing the noise output:-
- Within 1 metre from the enclosed units from 84dBa to 73 dBa
- On the ground at the base of the ID Fan 84dBa to 75dBa
- 50 Metres from the boiler, 63dBa to 56 dBa
The units are sounded every half hour between 7 am & 6 pm. There is no possibility of the nighttime restrictions being met.
Assessment of Trial after Three Months
After three months, an inspection was made & found no build up, the tubes being free except for a 0.5mm build up along the tops of the tubes. No cleaning required. The customer is removing 5 cubic metres from the multi clone each week. This would have been hanging up around the tubes prior to the installation of the Acoustic Cleaners.
If no cleaning is needed to be carried out, then the cost of the entire project would be recouped within 12 months. The project consisted of Rotary valves, Multiclone, installation, structural steel work, Acoustic Cleaners etc was $NZ207,000; The Acoustic Cleaners were approx 10% of that cost.