A series of experiments were conducted with Forintek’s MDF pilot plant to investigate the impact of various process parameters on MDF dryer stack emissions. Resin types, resin loading, wood furnish and scavenger levels were among the factors investigated in this study. Stack emissions were analyzed for particulate matters (PM), speciated volatile organic compounds (VOCs) and total volatile organic compounds (TVOC).
Two series of results were reported. During the first series of test runs, the isokinetic PM sampling was not obtained while with the second series, all test runs were conducted under isokinetic conditions, which make results more reliable. PM results from the second series of runs did not indicate a clear impact of the investigated refining conditions. However, all PM results were well below provincial guidelines for PM emission limits.
Other results clearly showed that increasing resin loading resulted in an increase of individual VOCs (IVOCs) and total VOC (TVOC). The replacement of UF resin by MUF resin contributed to a decrease of both IVOCs and TVOC. The addition of scavenger decreased stack emissions of both IVOCs and TVOC in agreement with what has been observed with the resulting MDF/HDF products suggesting that in order to reduce stack emissions one could reduce resin loading ratios or increase scavenger loading in the manufacturing process by keeping in mind to any modification of these processing factors will impact of products mechanical and physical properties and on the final production costs.
The two trials conducted at a mill member showed excellent results with deviations less than 20% between the duplicates for IVOCs and less than 2% for the TVOCs results. Because of confidentiality, the participating mill is not identified.