Agro-waste combustion in a circulating fluidized bed

In this study a circulating fluidized bed combustor (CFBC) of 125 mm inside diameter and 1800 mm height was used to investigate the combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry. A lignite coal was also burned in the same combustor. The combustion characteristics of the wastes were compared with that of a lignite coal that is most widely used in Turkey. On-line concentrations of O-2, CO, CO2, SO2, NOX and total hydrocarbons (CmHn) were measured in the flue gas during combustion experiments. By changing the operating parameters (excess air ratio, fluidization velocity, and fuel feed rate) the variation of emissions of various pollutants were studied. During the combustion tests, it was observed that the volatile matter from peach and apricot stones quickly volatilizes and mostly bum in the riser. It was found that as the volatile matter of fruit stones increases, the combustion takes place more in the freeboard region

Co-combustion of agricultural wastes in a circulating fluidized bed

In this study a circulating fluidized bed combustor (CFBC) of 125 mm inside diameter and 1800 mm height was used to investigate the co-combustion characteristics of peach and apricot stones produced as a waste from the fruit juice industry, and sunflower stems produced as a waste from the edible oil industry with a lignite coal. The lignite coal is a coal most widely used in Turkey. On-line concentrations of O-2, CO, CO2, SO2, NOX and total hydrocarbons (CmHn) were measured in the flue gas during combustion experiments. By changing the operating parameters (excess air ratio, fluidization velocity, and fuel feed rate) the variation of emissions of various pollutants were studied. During combustion tests, it was observed that the volatile matter from agro-wastes quickly volatilizes and mostly bum in the riser. The temperature profiles along the bed and the riser also confirmed this phenomenon. It was found that as the volatile matter content of agro-waste increases, the combustion efficiency increases and the combustion takes place more in the upper region of the riser. These results suggest that agro-wastes are potential fuels that can be utilized for clean energy production by using CFBC in countries where agricultural activities are heavy.

Investigating benefits from the implementation of environmental management systems in a Greek university

Higher Education Institutions (HEIs) can contribute significantly to the achievement of environmental sustainability through teaching and research activities, and also through improvements in the environmental management of University estates. This article explores the results of implementing Environmental Management Systems (EMSs) in a HEI in Greece. Specifically, the results of two surveys, focusing on students’ perceptions in the University of the Aegean, are presented and analysed. The surveys were conducted prior and after the implementation of an EMS in the University. The survey results demonstrate several positive consequences from the implementation of EMS across the University campus. In particular, there is a positive influence on students’ environmental awareness and behaviour, accompanied by greater preference among them for more participatory environmental management initiatives

Application of the BRC Sequential Extraction Scheme for Assessing the Leaching of Elements in Wood-Based Ash Fractions from a Large-Sized (115 MW) Industrial Power Plant of a Pulp and Board Mill

Extractions tests are widely used as tools to estimate the potential release of constituents, for example from waste materials, over a range of possible waste management activities, including recycling, reuse and landfill disposal. Sequential extraction procedures offer the advantage of simulating, to a certain extent, the vari ous natural environmental conditions. In this study, the mobility and bioavailability of heavy metals in wood-based bottom ash and fly ash was evaluated by the three-stage BCR sequential extraction procedure, in which elements in the bottom ash and fly ash were fractionated between acidsoluble (CH3COOH; BCR1), reducible (NH2OH-HCl; BCR2) and oxidisable (H2O2 + CH3COONH4; BCR3) fractions. For the bottom ash, the extractable concentration of Al (88 mg/kg; d.w.) and Ba (82 mg/kg; d.w.) in the BCR1 fraction were moderate, whereas the extractable concentrations of Mn (110 mg/kg; d.w.), S (310 mg/kg; d.w.) and Zn (200 mg/kg; d.w.) were relatively high. In the fly ash, the highest extractable concentrations in the BCR1 fraction were observed for S (14,400 mg/kg; d.w.) and Ba (26 mg/kg; d.w.). Therefore, when these ashes are disposed of in a landfill or utilized, for example, in earth construction, the above-mentioned metals are likely to be released from the bottom ash and from the fly ash since the elements associated with the acid-soluble (CH3COOH) fraction are more mobile and bioavailable than the metals in easily reduced (NH2OH-HCl) and oxidisable (H2O2 + CH3-COONH4) fractions.</p