Study on chicken manure combustion and heat production in terms of thermal self-sufficiency of a poultry farm

Abstract

According to regulations of the European Parliament and Council, chicken manure can be used on-site as a fuel to serve as a promising energy source. This study presents a characterization of a combustion process using mixtures of chicken manure with straw or wood (sawdust) in terms of thermal self-sufficiency of a poultry farm. The experiments were carried out in a small-scale laboratory reactor, as well as using thermogravimetric analysis (TGA) in an air atmosphere. The average maximum temperatures obtained during the combustion of all tested mixtures were similar, at approximately 1000 °C. Research showed that adding material with a higher volatile content (manure - 45%, straw/wood >80%) leads to an increase in the overall amount of volatiles in the mixture and a higher flame temperature. The content of volatile parts in the materials determines the flame temperature which rose along with the increase of addition percentage in the sample from 600 °C to 900 °C. On the other hand the addition of a large amount of straw to the manure leads to the formation of sinter on the grate due to low spherical/semispherical temperature of straw-based ash (∼1000–1100 °C). This problem was not observed during experiments for a mixture of wood and manure. Furthermore the NOx emission during combustion was lower for samples containing wood than for samples containing straw by 70 ÷ 280 mg/m3. The energy analysis of the tested samples showed that the on-site combustion of the manure and bedding mixture more than covers the heat demand of the henhouses.