This work investigates the cost-efficient integration of renewable hydrogen into steelworks for the production of methane and methanol as an efficient way to decarbonize the steel industry. Three case studies that utilize a mixture of steelworks off-gases (blast furnace gas, coke oven gas, and basic oxygen furnace gas), which differ on the amount of used off-gases as well as on the end product (methane and/or methanol), are analyzed and evaluated in terms of their economic performance. The most influential cost factors are identified and sensitivity analyses are conducted for different operating and economic parameters. Renewable hydrogen produced by PEM electrolysis is the most expensive component in this scheme and responsible for over 80% of the total costs. Progress in the hydrogen economy (lower electrolyzer capital costs, improved electrolyzer efficiency, and lower electricity prices) is necessary to establish this technology in the future.

The objective of the study was the analysis of trace elements contents in coals of the Upper Silesian Coal Basin (USCB), which may pose a potential threat to the environment when emitted from coal processing systems. Productive carbon overburden in central and southern zones of the USCB is composed mostly of insulating tertiary formations of a thickness from a few m to 1,100 m, and is represented by Miocene and Pliocene formations. In the data study the geological conditions of the coal seams of particular zones of the USCB were taken into account and the hierarchical clustering analysis was applied, which enabled the exploration of the dissimilarities between coal samples of various zones of the USCB in terms of basic physical and chemical parameters and trace elements contents. Coals of the northern and eastern zones of the USCB are characterized by high average Hg and low average Ba, Cr, and Ni contents, whereas coals of southern and western zones are unique due to high average concentrations of Ba, Co, Cu, Ni, and V. Coals of the central part of the USCB are characterized by the highest average concentration of Mn and the lowest average concentrations of As, Cd, Pb, V, and Zn.

The objective of the work was testing the suitability of X-ray Diffraction (XRD) and Scanning Electron Microscopy with X-ray microanalysis (SEM/EDS-Energy Dispersive X-ray Spectroscopy) for qualitative assessment of mercury present in coals and furnace wastes (slag, ash). Such information is essential e.g. for determination of the potential effects of waste coal dumps on the environment (mercury compound emissions through leaching and erosion to water and soil). No minerals of mercury, i.e. containing mercury as a necessary and substantial component were identified with the application of the above mentioned techniques in studied hard coal and fly ash samples provided by a heat and power plant. In hard coal, mercury was detected as an impurity only in the alumina silicates. EDS spectra of pure coal grains did not show the emission lines of mercury. In fly ash, the minerals of mercury were also not detected; mercury was present in an amorphous component (mineral glass) and probably as an impurity in hauyne Na3Ca(Si3Al3)O12(SO4)

This paper presents the results of a study on the influence of the temperature of characteristic zones of coal combustion in a stoker fired boiler (drying, degassing, and burn-out), on changes in physical and chemical parameters of bituminous coal and slags. This information is important as it helps identify the impact of coal properties on the accumulation of trace elements, primarily mercury, in combustion waste. The study is the continuation of research work on the impact of mercury compounds accumulated in combustion waste on the natural environment (mercury from landfills of slag, and fly ash). Studies were undertaken because no in-depth analysis of the impact of the temperature of particular zones of stoker fired boilers on the physical and chemical parameters of the post-process slag, including mercury content, had been reported in literature. Both of the coals examined, classified as bituminous coal according to the International Classification of Seam Coals and of type 32.1 according to the PN-G-97002:1982 standard, showed an average mercury content of 0.0849 μg/g. In the chemical composition determined for the ash derived from burnt coal, the dominance of SiO2 and Al2O3 over other oxides was found. This feature results in the increase of the softening temperature and ash melting and, therefore, during the combustion of coal tested in a stoker fired boiler, only ash was subjected to the sintering process. Mercury content in the other examined samples taken from various locations of the stoker fired boiler (drying – 32–1050 °C, degassing – 1050–1020 °C, and burn-out – 1020–400 °C) varied from 0.0668 to 0.0009 μg/g and was determined with the use of a LECO atomic absorption spectrometer. The analyses of the elemental composition, performed with the application of XRF spectrometry, for ash obtained from samples collected from different sampling points of the stoker fired boiler showed that the largest concentration of trace elements was observed for the ash derived from the samples collected in the degassing zone (temperature range 1050–850 °C)

This article presents the results of comparing mercury content measurements made with the AMA254 automatic atomic absorption spectrometer with measurements obtained using the CVAAS method in a different laboratory. The aim of the article is to show the potential of applying the AMA254 analyzer to measure low mercury content (including trace amounts) without the pre-treatment (mineralization) of the samples. Mercury, as one of the more toxic elements (Agency for Toxic Substances and Disease Registry), which is present in hard coal, is the main cause of the problems resulting from the environmental pollution associated with hard coal combustion, as well as storing coal processing waste, such as extractive waste and combustion by-products including slag, ash, and slag-ash mixtures (CBP). Precise measurements of trace mercury content in extractive waste and combustion wastes (CBP) is very important in the context of the act on waste (2008 and 2013), BAT regulations 2016 and new BAT regulations (coming into force by 2021), which introduce more and more rigorous limits on mercury emission into the environment. The AMA254 analyzer performs analysis in a short period of time (approximately 5 min), enables repeatability, is intuitive to use and has very high accuracy and precision (the lower limit of quantification is 0.00001 μg Hg), is an ideal tool for measuring low mercury content in samples of both fuels and coal processing waste.

The co-firing of coal and refuse-derived fuel (RDF) from municipal solid waste recycling is gaining support in countries in which energy production is based on solid fuels. It is the result of the rising priority given to renewable energy sources, the circular economy, and effective waste management through sorting, recycling, and thermal conversion. Despite the increasing efficiency of recycling and the ever-lower quantities of waste delivered to waste dumps, the problem of the residual fraction remains unsolved. The portion of mixed municipal waste that cannot be recycled exhibits a high energy value. For this reason, it should be neither stored nor burnt in household boiler rooms, as doing so would constitute an environmental hazard. However, the waste can be used as an additive to fine coal in power boilers, provided that they are equipped with flue gas monitoring and purification systems. Tests involving proportionally prepared compositions of fine coal and refuse-derived fuel burnt in a laboratory boiler revealed a major variability in the flue gas parameters (physicochemical), depending on the applied proportions of the individual components. For instance, when burning a composition of 50% fine coal and 50% refuse-derived fuel, a reduction in CO₂ emissions by about 12% was noted compared with that when burning fine coal exclusively. Furthermore, when burning refuse-derived fuel, an addition of 20% fine coal is enough to produce a 2.8% reduction in CO emission. Meanwhile, a composition of 80% fine coal and 20% refuse-derived fuel would reduce the emissions by 393 ppm. During the measurements, it was also noted that most of the measured parameters indicated a decrease in individual gas contents relative to the emissions obtained when burning fine coal or refuse-derived fuel exclusively. These relationships can be applied to prepare fuel compositions based on refuse-derived fuel and fine coal, depending on the power and flue gas purification capabilities of individual cogeneration systems.