6th International Ege Energy Symposium and Exhibition, İzmir, Turkey, 28 - 30 June 2012, pp.845-857, (Full Text)
In this study, co-combustion of Turkish Bolu-Goynuk lignite and Pinus brutia, the Turkish pine was carried out in a 30 kW thermal capacity of circulating fluidized bed combustor (CFBC) which has 108 mm in diameter and 6 m in height. CFBC system consists of a circulating fluidized bed combustor column, downcomer, a fuel feeding system, electrical heaters, and two cyclones. The combustion temperature was held at 850+50οC. The sizes of the coal and pine chips were between 1-2 mm. Coal and pine chips were fed into the bed from different hoppers. The coal was first combusted alone, and then 20% by wt. of pine chips was added. Then, pine chips addition was cut and limestone was added to coal with the Ca/S ratio of 2. In the last step pine chips (20% by wt.) and limestone (Ca/S=2) were added to coal in order to investigate the effect of biomass and limestone addition on the flue gas emissions. Flue gas emissions were continuously measured and recorded by Gasmet DX-4000 flue gas analyzer. Effect of excess air ratio (l) on the emissions were also investigated.
The results of the experiments showed that when the limestone and pine chips were added during coal combustion, SO2 was reduced. CO emissions increase as the biomass percentage increases in the fuel. Biomass fuels have high CO emission because of their high volatile matter content. In order to reduce CO emission, secondary air injection into the system is suggested.