Biomass is one of the most promising renewable energy sources because it enables energy accumulation and controlled production. With this, however, the demand for biofuels grows and thus there is an effort to expand their portfolio. Nevertheless, to use a broader range of biofuels, it is necessary to know their fuel properties, such as coarse and elemental analysis, or lower heating value. This paper presents the results of testing the fuel properties of several new, potentially usable biofuels, such as quinoa, camelina, crambe, and safflower, which are compared with some traditional biofuels (wood, straw, sorrel, hay). Moreover, the results of the determination of water content, ash, and volatile combustible content of these fuels are included, along with the results of the elemental analysis and the determination of higher and lower heating values. Based on these properties, it is possible to implement designs of combustion plants of different outputs for these fuels.

The gasification of sewage sludge (SS) and digestate was investigated in a pilot-scale fluidized bed gasifier with an output of 100 kW_t. The treatment of these by-products is an ongoing challenge for sustainable development. SS and digestate are most commonly used as fertilizers. However, regulations restrict their use, mainly because of the content of heavy metals, pathogens and bacteria. Gasification of these by-products instead of application to agricultural land seems to be more efficient, as the syngas can subsequently be used for combined heat and power (CHP) generation. A series of measurements were carried out to get a better understanding of the gasification process of these fuels and to study the effects of gasifying agent on the syngas composition, particulate matter (PM) and tar. The produced syngas and tar were analyzed using a gas chromatograph with mass spectrometry (GC–MS). The results showed that no ash slagging was observed and therefore it is feasible to operate digestate and SS gasification at 750°C. The lower heating value (LHV) of the syngas from digestate and SS with air as the gasifying agent is comparable, 4.06 MJ·Nm⁻³ for digestate and 4.11 MJ·Nm⁻³ for SS. The addition of steam had a positive effect on the amount of tar and the tar dew point, which was below 150°C. Tar reduction in digestate was 5037.3 mg·Nm⁻³ to 3566.3 mg·Nm⁻³ and in SS 7447.7 mg·Nm⁻³ to 3390.3 mg·Nm⁻³. Furthermore, the concentrations of the individual tar compounds were determined and subsequently divided into tar classes.

OPERATING SPECIFICATIONS OF CATALYTIC CLEANING OF GAS FROM BIOMASS GASIFICATION

The presented set of data contains experimental results from the combustion of various solid biofuels in a small-scale boiler. The biofuels were prepared from agricultural plant residues that included: 4 samples of Melilotus albus, 3 samples of Papaver somniferum, 1 sample of Medicago lupulina, Medicago sativa and Sinapis alba. The residues were processed into 8 mm pellets. Standardized spruce pellets were used as a reference material. The dataset includes basic fuel properties (moisture, ash and volatile matter content and LHV) and elemental composition (C, H, N, S, O). Compared to spruce pellets, the agricultural residues contain considerable amounts of nitrogen, and their combustion thus presents a potential environmental hazard. The combustion tests were carried out on an automatic pellet boiler with a bottom-feed retort burner. The emissions of NO_x were closely monitored and evaluated. The dataset serves primarily for the assessment of NO_x emissions from burning nitrogen-rich biofuels; however, other important parameters are included as well: CO, TOC emissions, O₂ content, flue gas temperature and boiler power output.