Solid biofuel combustion

The solid biofuel combustion facility contains test cells for small scale boilers and batch-wise operated stoves. In addition, the facility consists of  a multifuel grate combustion reactor (40 kW) for versatile combustion studies, including aspects from ash behavior, and heat exchanger fouling to formation and characteristics of air emissions. The facility also offers a possibility for test and development work of emission reduction technologies for biomass-fired appliances.

Small-scale heaters, stoves and boilers

The small-scale combustion research facility is equipped with several log-wood fired stoves and heaters and with a modern pellet boiler (25 kW, Biotech). At the test cell of the batch-fired combustion units the heater is situated on a scale to measure the fuel usage during the combustion and enables balance calculations of the flue gas flow, thermal output and efficiency. The test cell of boilers includes a heat exchanger and sensors to measure heat output and efficiency. In both cases the combustion gases are led through a stack which is equipped with several sampling ports. The draught in the stack can be adjusted by an exhaust fan and changing the location of the hood.


Tissari et al., 2015. Zinc nanoparticle formation and physicochemical properties in wood combustion - experiments with Zn-doped pellets in a small-scale. Fuel 143, 404–413.

Tissari et al., 2009 The effects of operating conditions on emissions from masonry heaters and sauna stoves. Biomass and Bioenergy 33, 513–520.

Multifuel grate combustion reactor

The grate combustion reactor allows controlled and well-adjustable combustion of various solid fuels, serving as a flexible experimental system for various studies on combustion processes, ash behaviour and emission formation. The system includes a 40 kW solid -fuel burner, a fully logic-controlled fuel feeding system, a ceramic insulated combustion chamber and a firetube boiler with a cooling circuit. The moving  reciprocating grate burner is designed for solid biomass e.g. wood chips, pellets, peat and straw, and it is also suited for melt-forming fuels. The setup can be easily modified and different burners, heat exchangers and various emission reduction technologies can be connected to the system, depending on the research needs. The setup includes an option to use oil or gas burner simultaneously with the solid fuel burner. In addition, an electrically heated drop tube furnace can be connected to the system when well-defined temperature conditions are required (e.g. high temperature sampling studies, corrosion studies).


Kortelainen, M., Nuutinen, I., Jokiniemi, J., Torvela, T., Lamberg, H., Karhunen, T., Tissari, J., Sippula, O. (2015) Ash behavior and emission formation in a small-scale reciprocating-grate combustion reactor operated with wood chips, reed canary grass and barley straw. Fuel 143, 80-88.

Grigonyte, J., Nuutinen, I., Koponen, T., Lamberg, H., Tissari, J., Jokiniemi, J., Sippula, O. (2014) Evaluation of a Heat Exchanger designed for Efficient Fine Particle Precipitation in Small-Scale Wood Combustion. Energy & Fuels 28, 6058-6065.