Recent advances in biofuel drying

Sweden must be regarded as one of the leading countries to utilize biofuels for heating purposes. A national survey of technique and economy for biofuel drying systems has therefore been deemed to be of wider interest. As well flue gas dryers as steam dryers are used but in different applications. Operating experiences from both types are reported. A thermodynamic analysis of various system solutions is also performed. Rotary flue gas dryers dominate the market in fuel factories, which are not colocated with other industrial activities. Steam dryers are best suited for integrated systems, where their capability for heat recovery can be exploited. A new approach is to recover electricity instead of heat. This is accomplished in a system integrated in a district heating plant with power cogeneration. The environmental issues are of ever increasing concern and the release of volatile organic compounds (VOC) during drying and influence of the fuel moisture content on emissions from the combustion are discussed.