Co-Combustion of Forestry Biomass with Tyres in a Circulating Fluidised Bed Combustor

Abstract

Combustion studies of mixtures of forestry biomass and used tyres were undertaken in an atmospheric circulating fluidised bed. The combustor was operated over a temperature range of 700 to 1000 °C.

The main parameters that were investigated are i) where and how to feed both forestry biomass and used tyres to the combustor, ii) the ratios of amounts of forestry waste/used tyres, iii) air staging, and iv) excess air levels along the riser.

Whole waste tyres are usually incinerated in cement kilns. There are boilers designed to burn whole tyres but the experience has not been successful because the time for combustion is not long enough, the temperature is relatively lower for complete combustion and the distribution of air has been proven to be insufficient. The work of INETI investigates the combustion of waste tyres which are reduced in size prior to their burning in a fluidised bed. This type of combustion studies with waste tyres is new and as results obtained by far are encouraging this option could be an alternative to the eventual utilisation of waste tyres as a boiler fuel.