Summer – time to work!
17 July 2015
What is it all about? A pellet plant being currently constructed in Uddevalla (a town in the West of Sweden), which is to be put into operation as soon as in August! What is special about the idea of a pellet plant working in summer time? Basically nothing, if not considering the fact that it is to operate only in summer.
Just a small note – not only in summer time, but during the whole warm season that due to the climate peculiarities lasts in Sweden no longer than, e.g. in Siberia.
Isn’t it improvidently to construct a plant designed for seasonal work and what lies behind that? Innovative and rational approach to different tasks has always been one of the key features of the Swedes, with this case not being an exception.
A special pellet plant
In fact a new pellet plant is being constructed in the dump site. Although sounds strange, it actually means literally that the plant will operate in close cooperation with the local power station, where household wastes are used as raw materials. Power station capacity of only 35 MW (10 MW of electric energy) is enough to provide the whole town and its suburbs with population of about 50 th. people with electricity, heat and hot water.
Construction of the pellet plant is primarily aimed at ensuring ecofriendly and cost-effective utilization of household wastes. The appearance of garbage is not a seasonal issue, it must be utilized year -round, which in this particular case requires continuous operation of the boiler house. But, how is it all related to pellets?
During warm season, when central heating system is closed, there is a significant excess of heating energy generated by power station for electricity production. That is the very same excess that Uddevalla municipality decided to use rationally.
The operating pellet plant is to consume 1.0-1.2 MW/h of heating energy for production of each ton of pellets (for raw material drying). The plant not working year-round, it is rather difficult to calculate its annual production capacity, however, as calculated per hour, production capacities will allow getting at least 14 ton of pellets, which can be increased in future.
To utilize the excess of heat energy in the technological process of pellet production there exist special solutions that allow application of a low temperature (~80°C) heat carrier. Belt dryer for sawdust is the best of the solutions existing today.
Otherwise Uddevalla project – with Hekotek being a general supplier – is rather typical from the technological viewpoint: 3 pellet presses by CPM (the Netherlands) and complex machinery of the pellet plant, including automation and control system all supplied by Hekotek.
As for the ready pellets storage, the choice was made in favor of huge silos (2 silos of 4 th. ton each) due to seasonal operation of the pellet plant, which allows producing a significant stock of pellets to be dispatched later.
Interesting is the fact that selling pellets is not the only income item in this Swedish project. The new pellet plant will ensure not only effective use of the excess energy produced within household wastes utilization. Due to pellet production the power station in Uddevalla will be able to accept more wastes and, thus, generate more electric energy, getting significant additional income in both cases. These two income stipulating constituents definitely made the business plan of the future pellet plant especially attractive, and due to that the idea of seasonal pellet production generated a strong interest from both nearby towns in Sweden and other countries.