Effect of some treatments on emission of volatile organic compounds (VOC) from chips used in pellets making processes

Abstract

Emission of volatile organic compounds (VOC) from wood during processing to pelletssignificance of wood extractives. Cellulose, hemicelluloses and lignin are the main components of the cell wall in wood. Moreover, wood contains different amounts of extractives, depending on the wood species. Extractives in softwoods play an important role during processing of wood to different wood products. This work studies the influence of storage on the change of extractives as well as on the emission of monoterpenes (primary emission) and aliphatic aldehydes, as degradation products of fats and fatty acids (secondary emission). In case of pine wood storage for 2 days at 80uC proved to be more efficient in the reduction of emissions of terpenes and aldehydes than 4 weeks at 40uC. Quantitative differences between pine (Pinus sylvestris) and spruce (Picea abies) wood chips in the emission were evaluated and discussed. Pinewood emits about 10 times higher amounts of terpenes and aldehydes than spruce wood. The results indicate that the intense of change in primary and secondary emissions due to storage depends on the wood species as well as on the boundary conditions under which storage is carried out. In general, storage at high temperature (80uC) is much more effective than at low temperature (40uC). The results also reveal that removal of wood extractives from pine wood by extraction with ethanol-cyclohexane or treatment with sodium hydroxide decreases the emission of primary and secondary volatile organic compounds drastically. Nevertheless, after such treatments minute amounts of volatile organic compounds are still detectable.

The Proof-of-the-Concept of Application of Pelletization for Mitigation of Volatile Organic Compounds Emissions from Carbonized Refuse-Derived Fuel

“…Moreover, the amount of cold-water extractives of spruce wood increases, indicating some hydrothermal degradation of wood during the process of pellet making. Especially, the pressing process at high temperature and pressure appears to thermally degrade wood [36].…”

“…Usually, the produced RDF, due to the risk of self-heating and, in consequence, fire and even explosion [20], is not stored longer than a couple of days. Similarly, wood pellets storage is not recommended to be longer than several days [36]. By analogy, in this paper, we focused on the proposed four days of CRDF storage as being the ‘worst case’ scenario for a production facility and explored VOC emissions.…”

Effect of oxidising and reducing agents on the release of volatile organic compounds (VOCs) from strands made of Scots pine (Pinus sylvestris L.)

“…Interesting results related to the emission of volatile organic compounds have been obtained by Gabriel et al (2014). They established that even after extraction of pine chips with ethanol-cyclohexane, a well-known method for removal of extractives, the chips still emit VOCs, albeit very small amounts.…”

Comparison on Reduction of VOCs Emissions from Radiata Pine (Pinus Radiata D. Don) between Sodium Bicarbonate and Ozone Treatments

“…However, the content of the solvent that remains in the treated samples is high. Some studies have also shown that extraction with ethanol-cyclohexane can significantly reduce the emission of terpenes and aldehydes in pine [18]. The reduction of VOCs by extraction has not been widely used due to the high content of solvent that remains in the treated wood.…”

“…Alkali treatment is a common chemical treatment, and studies have shown that alkaline solutions can promote the hydrolysis of fats and resins in wood [19]. It has been found that the sodium hydroxide solution can partially remove terpenes and aldehydes from pine extract [18]. Sodium bicarbonate has been used as a buffer to significantly reduce the VOC contents in styrene-acrylate emulsion [20] and acrylic elastic emulsion [21].…”