Assessment of air emissions from industrial kiln drying of Pinus radiata wood

Abstract

The nature and mass flows of atmospheric emissions from an industrial kiln, drying radiata pine (Pinus radiata D. Don) at 100°C dry bulb and 70°C wet bulb, were assessed by measuring the concentration of chemical components in the kiln atmosphere at regular time intervals and determining air-flows and temperature differentials across the stack. The volatile organic compounds (VOC) were trapped on activated carbon and analyzed by GC-MS. The aldehydes were trapped in 2,4-dinitrophenol-hydrazine solution and the aldehyde derivatives analysed by HPLC. Polar compounds were trapped in water and then alcohols were analysed by GC and organic acids by ion exchange chromatography. The two major VOC found were a-pinene and b-pinene, which made up 90% of the total discharge (405 g/m 3 wood). Most of the VOC fraction was released during the early stages of drying. The release of potentially hazardous components (formaldehyde, acetaldehyde, furfural) was found to be relatively low (1.1, 8.7, and 0.1 g/m 3 wood, respectively) provided the kiln emissions are well dispersed, these levels of release are unlikely to cause adverse environmental effects. Abschätzen der Luftemissionen beim industriellen Trocknen von KiefernholzArt und Menge der gasförmigen Emissionen während des industriellen Trocknens von Kiefernholz (P. radiata D. Don) wurden abgeschätzt. Die Trockentemperatur betrug 100°C, die Feuchttemperatur 70°C. Chemische Komponenten in der Ofenluft wurden in regelmäßigen Zeitintervallen gemessen sowie die Luftbewegungen und Temperaturdifferenzen innerhalb des Holzstapels bestimmt. Die flüchtigen organischen Bestandteile (VOC) wurden an Aktivkohle adsorbiert und mittels GC-MS analysiert. Aldehyde wurden in Lösungen von 2,4-Dinitrohydrazin aufgefangen und die entsprechenden Aldehydderivate mittels HPLC analysiert. Polare Komponenten wurden in Wasser absorbiert, wonach die Alkohole mittels GC und die organischen Säuren mit Ionenaustauschern aufgetrennt wurden. Die Hauptkomponenten der VOC waren Alpha-und Beta-Pinen, die zusammen 90% des Massenverlustes (405 g/m 3 Holz) ausmachten. Die Hauptmenge wurde im frühen Trockungsstadium freigesetzt. Die Freisetzung von eventuell schädlichen Komponenten war relativ gering (Formaldehyd 1,1 g/m 3 , Acetaldehyd 8,7 g/m 3 und Furfural 0,1 g/m 3 ). Wenn die Ofenabluft gut verdünnt ist, sollten diese Mengen kaum Umweltschäden verursachen.

Volatile organic compounds emitted from hardwood drying as a function of processing parameters

“…Examples of typical thermal degr adation products are methanol, formaldehyde (Barry and Corneau, 2006;Su et al, 1999), acetaldehyde (McDonald et al, 1995), pentanal, hexanal (Otwell et al, 2000) formic acid, acetic acid, alcohols and furfurals (Bridgwater et al, 1995). There are studies published on thermic degradation emissons from lumber drying (McDonald et al, 2002;Milota, 2006), rotary drum drying of fragmented wood (Banerjee et al, 2006) and drying in a ceramic tube furnace (Otwell et al, 2000;Su et al, 1999). The results from these studies are not necessarily transferable to the drying of sawdust in spouted/fluidized beds.…”

Evaluation of hydrocarbon emissions from heart- and sapwood of Scots pine using a laboratory-scale wood drier

“…McDonald et al (2002) reported that in addition to the monoterpene emissions, small amounts of diterpenes were present. In the present work a large amount of pimaral is released when drying the heartwood of pine at higher temperatures (above 708C).…”

“…The appropriateness (Word et al 1998) as well as the inappropriateness (McDonald et al 2002) of this method for detection of compounds such as formaldehyde, formic acid and methanol have been emphasized. An alternative method has been reported by Dallons et al (1994) who utilized a Total Hydrocarbon Analyzer to measure the levels of VOC from wood samples obtained before and after the drying process.…”

Antifungal and Antioxidant Activities of Volatile Organic Compounds Generated During the Drying Process of Chamaecyparis obtuse

“…편백나무는 열기 건조가 진행 되는 동안 다양한 휘발성 유기화합물들을 포함한 기체를 발생한 다 (Cronn et al, 1983;Mcdonald and Wastney, 1995). 지금까지 편백나무의 정유성분에 대한 생리활성 효과로는 항생효과, 살충 효과, 타감효과 등이 보고되고 있다 (Yaeno et al, 2003;Gwak et al, 2006;Park et al, 2008 (Englund and Nussbaum, 2000;McDonald et al, 2002). 이와 같은 terpenoids는 식물 자신의 보호 기능을 넘어 인 간에게 항 염, 항 바이러스, 항 박테리아, 면역기능 강화 등의 효 과를 가지고 있다 (Soliman et al, 1994;McGarvey and Croteau, 1995;Vila et al, 1999).…”