Pellet combustion tests at Helsingin Energia’s Hanasaari power plant have proceeded as planned. The tests seem to indicate that wood pellets could be mixed with coal at a ratio of 5–7%.
The plant has been wound down for the summer with the time being used to analyse in more detail the effects of pellets on the boiler and other equipment of the power plant.
Since autumn 2012, as part of Helsingin Energia’s Development Programme towards a Carbon-Neutral Future, tests have been conducted at the Hanasaari power plant to evaluate the possibility of combusting wood pellets with coal.
These tests are designed to prepare the Hanasaari and Salmisaari plants for continuous co-combustion of biofuels starting in 2014. The aim of the experiments is to find out what percentage of the coal combusted by the power plant can be replaced with wood pellets without significant modifications to the existing pulverisers and burners. A further goal was to determine the emissions from and behaviour of pellet combustion in the combustion process of a large plant.
“For example, the performance of coal pulverisers when using pellets could be improved. With our current equipment, we can combust pellets at a ratio of 5-7%. Our tests seem to indicate that it would be difficult to increase this ratio in continuous combustion without additional investments,” says Jarmo Hagström, Manager of Helsingin Energia’s Hanasaari power plant.
The tests were also aimed to show how pellet combustion would contribute to the contamination and corrosion of the boiler. Samples taken from the boiler will be analysed over the summer.
So far, domestic wood pellets have been used in the trials. In autumn, tests will be continued using other kinds of pellets.