Role of aldehydes in biomass combustion and pulp and paper industry

• Main Author: Khan, I. (Imran)
• Format: Dissertation
• Language: English
• Published: University of Oulu 2014
• Subjects: Environmental Engineering
• Online Access: http://urn.fi/URN:NBN:fi:oulu-201405281517; http://nbn-resolving.de/urn:nbn:fi:oulu-201405281517

The purpose of this study was to investigate the role of aldehydes in two industrial sectors; biomass combustion and pulp and paper industry. Aldehydes are formed as unwanted intermediate compounds during biomass combustion, however in pulp and paper industry formaldehyde could be an important end product when treating the waste gas streams. Biomass fuels are the major renewable energy sources used in industries due to their environmental benefits. Emissions from biomass combustion depend on the composition of fuel and combustion conditions. In this work, emissions from the combustion of various solid biomass fuels in industrial scale boilers have been studied by a literature survey. It was observed that formaldehyde and acetaldehyde were the predominant intermediate compounds formed during biomass combustion. European Union directives 1999/30/EC and 2008/50/EC provide limiting values for the emissions from biomass boilers to protect human health. Aldehydes are unregulated pollutants that are toxic in nature and can cause adverse effects to human health and the environment. Black liquor is formed in pulp and paper industry during wood processing. Black liquor contains organic matter which can be used as an important biomass fuel in the recovery boiler. Pulping and bleaching processes of a pulp mill release hazardous compounds like methanol and methyl mercaptan. These compounds are commonly treated by incineration in a boiler. Incineration converts the waste stream to carbon dioxide and water thus increasing the greenhouse gases. Currently research is in progress to develop alternative ways for utilizing methanol containing waste gas streams, by converting them to other valuable compounds. In this regard catalytic oxidation has become a very promising technology. This is an environmentally friendly way to treat these emissions and in addition it has a positive economic impact on the pulp mill. This route is in experimental level and needs further research for its application in industrial scale. Formaldehyde is a very useful compound as it can be further utilized in a number of industries for the production of other compounds.