Combustion of agro-waste with coal in a fluidized bed


CLEAN TECHNOLOGIES AND ENVIRONMENTAL POLICY, vol.12, no.1, pp.43-52, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 12 Issue: 1
  • Publication Date: 2010
  • Doi Number: 10.1007/s10098-009-0220-9
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.43-52
  • Keywords: Biomass combustion, Olive cake, Peach and apricot stone combustion, Bubbling fluidized bed combustion, BIOMASS, COCOMBUSTION, BEHAVIOR, EMISSIONS, STRAW
  • Middle East Technical University Affiliated: Yes


In this study, a review of the studies done on the co-combustion of some agro-waste in a bubbling fluidized bed combustor (BFBC) having an inside diameter of 102 mm and a height of 900 mm is given. The agro-waste used to investigate the co-combustion characteristics were peach and apricot stones produced as a waste from the fruit juice industry, and olive cake produced as a waste from the olive oil industry. These are typical wastes for a Mediterranean country. A lignite coal was used for co-combustion. On-line concentrations of O(2), CO, CO(2), SO(2), NO (x) and total hydrocarbons (C (m) H (n) ) were measured in the flue gas during combustion experiments. Variations of emissions of various pollutants were studied by changing the operating parameters (excess air ratio, fluidization velocity and fuel feed rate). Temperature distribution along the bed was measured with thermocouples. Emissions were also monitored from the exhaust. Various combinations of coal and biomass mixtures were tested. During the combustion tests, it was observed that the volatile matter from the biomass quickly volatilizes and mostly burns in the freeboard. The temperature profiles along the bed and the freeboard also confirmed this phenomenon. It was found that as the volatile matter of the biomass increases, combustion takes place more in the freeboard region. Better combustion conditions occur at higher excess air ratios. The results showed that co-combustion with these three proposed biomasses lowers the SO(2) and NO (x) emissions considerably. CO and hydrocarbon emissions are lower at the higher excess air ratios.