engleski

The perspective and problems of straw using as a renewable source of energy

Straw as a cereal crop residue has a big potential for bioenergy. As a rule cereal crops occupy the biggest part of arable lands in European countries. Nevertheless, in accordance with expert estimation about 2 million ton of straw may be potentially used for energy purpose. In Europe, the leader in using straw for energy is Denmark. The annual utilization of straw in this country is about 1.3-1.4 mln. ton. The calorific value of straw is 10–17 MJ/kg depending on type of crop, variety, fertilizer and other factors. In accordance with the National Programme of Republic of Belarus for development of local energy, the annual volume of straw for energy purpose should be 1 mln. ton, which corresponds to 0.3 mln. toe. One of the key problems for using straw is a high content of several elements in biomass (chlorine, potassium, sodium) which cause slagging of pipes and accelerates corrosion of the metal surfaces of the boiler during combustion. Other problem is high air pollution by sulphur after straw combustion. The problems may be solved by elution of chemicals from straw biomass. This method can be used in the field after harvesting as well as at a power plant. In our research the straw was left after harvesting in the field for several weeks. The content of water in straw biomass increased for 2-2.5 times. The correlation of water content and some chemicals in biomass was established, and a regression analysis was conducted. The coefficient of determination with water content for sulphur was 0.7-0.8, for chlorine 0.65-0.7, for potassium 0.3-0.4, depending on the type of cereal crop. The problem is that the high water content decreases the efficiency of biomass utilization for energy. Nevertheless, our results may be used for optimization of logistic of using of straw for energy production on the base of optimal balance of water content and chemicals contents in biomass ensuring the safe and efficient boiler operation

straw, renewable energy, contents of chemicals, boiler, pollutants reduction

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