In Poland the use of solid biomass obtained from intentional plantations of energy plants is increasing. This biomass is most often processed into solid fuels. There are growing indications that renewable energy sources, in particular biomass production, will continue to develop, so the better we know the raw material, the more effectively we will be able to use it. The results of tests that determine the impact of compaction pressure on selected quality parameters of pellets made from selected biomass types are presented. Material from plants such as Giant miscanthus (Miscanthus × giganteus Greef et Deu), Cup plant (Silphium perfoliatum L.), Virginia mallow (Sida hermaphrodita (L.) Rusby) was studied. The compaction process was carried out using the SIRIO P400 hydraulic press with a closed chamber with a diameter of 12 mm. Samples were made in four pressures: 131; 196; 262; 327 MPa and three moisture levels: 8%, 11%, 14%. It was found that with increasing compaction pressure and moisture content up to a certain point, the density and durability of the pellets also increased. Each of the materials is characterized by a specific course of changes in the parameters tested.

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Renewable energy sources (RES) represent an increasing share of global energy production. Biomass has the highest potential of all RES. Biomass is used to produce solid biofuels, liquid biofuels, and gaseous biofuels. One of the main directions of research on solid biofuels is to optimize the agglomeration process. The main factors determining the characteristics of the final product in the production of pellets are process and material parameters. Process parameters include compaction pressure, temperature, and geometry of the matrix channel. The parameters of the material are the type of biomass, moisture content, degree of fragmentation, and method of preparation of the material (e.g., drying). The process of pressure compaction is always associated with the negative phenomenon of elastic springback. The aim of this work was to check the influence of compaction pressure and material moisture content on the springback value. The research was conducted on three materials (giant miscanthus, cup plant and Virginia mallow), using four different pressures (131, 196, 262, and 327 MPa) and three different moisture levels (8, 11, and 14%). For all material springback values, the range was 9–16%. Statistical analysis showed that for all plants tested, the effects of compaction pressure and moisture content significantly affected the elastic springback value. Areas of high value springback in the pattern of process parameters were determined.

Fruit and vegetable processing is a difficult problem in the food industry. The raw materials are characterized by limited durability, and at the same time may belong to highly different varieties and species, which is why their suitability for processing varies. The most important task of the agricultural and food industry is to secure harvests so that they can be consumed throughout the year. The factors that determine the quality of fresh and processed food are primarily the type and quality of the raw material, the type of pre-treatment and further processing, as well as the conditions under which the raw material and the finished product were stored. The scope of the paper includes:-preparation of raw material samples (slices),-pre-treatment (blanching in steam, soaking in a starch solution),-drying the raw material (dryer with air circulation, no air circulation),-rehydration of the dried material (cold and warm water, time: 150 minutes). On the basis of the conducted tests, it was found that in the case of patches, the largest mass after the rehydration process was shown by samples dried in an air dryer, blanched in steam and rehydrated in hot water. In comparison with the mass of the fresh raw material, the patch after rehydration returned in 85.5 % to its initial state. The weakest effect on the mass gain of the dried slices results from pre-treatment in the starch solution, drying without air circulation, and then rehydration in cold water. None of the samples after 150 minutes of hydration reached the mass of the fresh raw material.

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