Recently, biomass application as a renewable energy source is increasing worldwide. However, its availability differs in dependence on the location and climate, therefore, agricultural residues as cow dung (CD) are being considered to supply heat and/or power installation. This paper aims at a wide evaluation of CD fuel properties and its prospect to apply in the form of pellets to direct combustion installations. Therefore, the proximate, ultimate composition and calorific value were analyzed, then pelletization and combustion tests were performed, and the ash characteristics were tested. It was found that CD is a promising source of bioenergy in terms of LHV (16.34 MJ·kg−1), carbon (44.24%), and fixed carbon (18.33%) content. During pelletization, CD showed high compaction properties and at a moisture content of 18%, and the received pellets’ bulk density reached ca. 470 kg·m−3with kinetic durability of 98.7%. While combustion, in a fixed grate 25 kW boiler, high emissions of CO, SO2, NO, and HCl were observed. The future energy sector might be based on biomass and this work shows a novel approach of CD pellets as a potential source of renewable energy available wherever cattle production is located.

A b s t r a c t. This paper compares the densification work necessary for the pressure agglomeration of fine-grained dusty nettle waste, with the densification work involved in two-stage agglomeration of the same material. In the first stage, the material was pre-densified through coating with a binder material in the form of a 5% potato starch solution, and then subjected to pressure agglomeration. A number of tests were conducted to determine the effect of the moisture content in the nettle waste (15, 18 and 21%), as well as the process temperature (50, 70, 90 o C) on the values of densification work and the density of the obtained pellets. For pre-densified pellets from a mixture of nettle waste and a starch solution, the conducted tests determined the effect of pellet particle size (1, 2, and 3 mm) and the process temperature (50, 70, 90 o C) on the same values. On the basis of the tests, we concluded that the introduction of a binder material and the use of two-stage agglomeration in nettle waste densification resulted in increased densification work (as compared to the densification of nettle waste alone) and increased pellet density.K e y w o r d s : agglomeration, nettle waste, binder, starch INTRODUCTIONOne of the types of post-production waste produced in herbal companies is the nettle waste obtained during herb processing. The amount of waste left over from the process of herbal production is relatively large, with its utilisation being problematic due to the very small particle sizes of waste fractions.In the case of Herbapol Białystok S.A., the annual production of herbal (usually nettle) waste, amounting to approx. 30 t, is usually sold cheaply or given away for a refund of the transport price.The most common method of herbal waste management is using herbal waste as a fodder additive. Depending on the species of the plant used, herbs exhibit bactericidal (e.g. sage), immunostimulating (Echinacea), antioxidant (e.g. rosemary), sedative, and soporific (e.g. melissa) properties. They can also lower cholesterol levels in the body. In addition, some of these improve the aroma and flavour of fodder. In order to take advantage of this range of properties, mixtures of different plants are often used (Hanczakowska, 2007). The effect of herbal additives in pig fodder on nutritional results is presented in a paper by Paschma (2004), among other studies.One of the methods of plant biomass waste management, including fine-grained herbal waste, is its pelleting or briquetting into a solid fuel (pellets, briquettes), and then using the resulting product as fodder or fuel (subjecting it to combustion). Various kinds of post-production plant waste have been densified into the form of pellets or briquettes: olive tree pruning residues (Carone, 2010), cork powder waste (Montero et al., 2014), blends of poplar and pine sawdust (Monedero et al., 2015), corn stover and switchgrass (Mani et al. 2006a(Mani et al. , 2006b, rice straw and rice bran (Chou et al., 2009), herbaceous crops (Gilbert et al., 2009, mixtures...

Abstract. In the work there are shown the results of experimental studies on methane rich gasification of pinewood pellets in Bio-CONOx technology. The experiment was carried out on a laboratory scale gasifier (5 kW), which design features allow producing a high quality gas with a high methane content. In the results there was identified the impact of the quantity of Bio-CONOx on the amount of flammable gas compounds (methane, hydrogen and carbon monoxide) in the synthesis gas and the gas calorific value. The additive was added in 10,20,30 and 50% concentrations to the gasifier chamber. It has been shown that increasing the amount of the additive has a positive effect on the calorific value of the synthesis gas ( Fig.1,2). Gas with a high content of methane (and high calorific value) was obtained from gasification of biomass with a 50% addition of Bio-CONOx. There was also examined the proportion of blowing air (gasifying medium) for which the properties of obtained syngas were the best.

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