The determination of mercury content in the biomass untended for industrial power plant

Abstract

Biomass is one of the oldest and most widely used renewable energy sources. The biomass is the whole organic matter of vegetable or animal origin which is biodegradable. Biomass includes leftovers from agricultural production, forestry residues, and industrial and municipal waste. The use of biomass in the power industry has become a standard and takes place in Poland and other European countries. This paper discusses the correlation of mercury content in different biomass types used in the power industry and in products of biomass combustion. Different biomass types, which are currently burned in a commercial power plant in Poland, were discussed. A photographic documentation of different biomass types, such as straw briquettes, wood briquettes, pellets from energy crops (sunflower husk and wood husk), wood pellets, wood chips, and agro-biomass (seeds) was carried out. The presented paper discusses the results obtained for 15 biomass samples. Five selected biomass samples were burned in controlled conditions in the laboratory at the University of Silesia. The ash resulting from the combustion of five biomass samples was tested for mercury content. A total of twenty biomass samples and its combustion products were tested. Based on the obtained results, it was found that any supply of biomass, regardless of its type, is characterized by variable mercury content in dry matter. In the case of e.g. wood chips, the spread of results reaches 235.1 μm/kg (in dry matter). Meanwhile, the highest mercury content, 472.4 μm/kg (in dry matter) was recorded in the biomass of straw, wood pellets, and pellets from energy crops (sunflower husk). In the case of combustion products of five selected biomass types, a three or four fold increase in the mercury content has been observed.