A b s t r a c t. This article deals with energetic evaluation and potential of pomace -a waste product originating during production of grape wine. Calorimetric analysis of 19 grapevine varieties was performed in 2013 and 2014. The aim was to specify their combustible limit and the gross calorific value. The evaluations were performed on pristine pomace, pomace without seeds, and only on seeds themselves. The results obtained imply that pomace is an interesting energetic resource with a gross calorific value of 16.07-18.97 MJ kg

Abstract. The paper called 'Possibilities of using grape marc for making fuel pellets' is focused on the topic of efficient usage of grape marc as a renewable energy source. From a global point of view, grapevine pressings, a byproduct of the wine industry, present a significant source of biomass. The organisation Internetionale de la Vignet et du Vin (OIV) estimates that there are over 66.5 mil. tons of grapevines manufactured globally, from which 38 mil. tons in Europe. This means that only in European conditions, there are approximately 8 mil. tons of grape pomace produced. Empirical measurements took place in the years 2013-2015 at grape marc samples from viniculture subjects in the wine-growing area Morava. The results of this paper are divided into two main parts -grape marc usage for energy purposes and for pellet production. There was implemented a wide range of calorimetrical measurements of combustion heat and caloric power of grape marc in its original state, grape marc after seed separation (assumption of oil pressing usage), and in seeds themselves. The results indicate that the heating power varies between 16.07-21.14 MJ·kg -1 . The highest heating power values were stated by seeds and grape marc in its original state. It could be presumed that the main reason is rather high oil component in grapevine seeds. Moreover, the measurement set was supplemented by results focused on grape marc usage for pellet production. Different proportions of dried grape marc combined with wine shoots and hay were used as the input materials. The measured values imply that the highest heating power (19.22 MJ·kg -1 ) was obtained from pellets composited from 60 % grape marc, 20 % wine shoots, and 20 % hay. Their apparent density is 630.9 kg·m -3 . The produced pellets correspond with the norm CSN EN 15210-2 from the perspective of mechanical ruggedness.

The paper deals with the evaluation of the separation efficiency on planar vibrating separator and the purity of the separated seeds from marc of selected grape varieties. Measurements were made in 2013 for the varieties as follows: Traminer, Sauvignon, Riesling, Grüner Veltliner, Riesling, André, Lemberger, Cabernet sauvignon, Cabernet Moravia, Zweigeltrebe. Total weight of the collected samples was 70 kg. From the results obtained it is evident that all of the observed separation efficiency varieties is high and varies between 63-83%. The lowest seed yield was found in Sauvignon (13,9%) and Riesling (15,9%), the highest in the variety André (33,7%). Purity of the separated seeds in most samples was relatively stable (76-90%).

The contribution describe the possibilities of using marc for manufacturing pellets for energy purposes. Experiments associated with pellet production were performed in several variants. Biomass pellet variants consisted of diff erent percentages of vine shoots from vineyards, as well as marc and hay. These test variants were measured for their calorifi c value, which ranged between 17.36 and 19.21 MJ.kg −1. Bulk density was also determined, ranging between 619.27 and 630.9 kg.m −3. Pellets produced with marc content were also tested for mechanical durability, which was between 96.15 and 96.82% for the test variants. The calorifi c value, alongside other parameters assessed, shows favourable characteristics towards use in combustion processes. The results obtained show that in terms of the parameters analysed, marc pellets could be an attractive commodity for combustion.