RESUMEN
The main purpose of this research was to determine the chemical composition of deposits in gas engines fuelled by coal mine methane (CMM), as well as its dependence on the place of collection. This composition was compared with that for deposits formed in biogas-powered engines. It was also found that the chemical composition of deposits varies depending on the place of their formation in the engine and on the gaseous fuel used. The dominant mineral deposits found in gas engines fuelled by CMM contained Ca, Zn, P, and S, which originate from oil additives. The Al, Cr, Cu, Ti, and Fe elements present in the tested samples are related to the wear of the engine under normal operation. The remaining trace elements can originate as impurities from the air.
RESUMEN
Municipal landfills generate a significant amount of high-energy biogas, which can be used as a renewable gaseous fuel. However, it is necessary to improve the quality of this biogas due to the presence of various chemical compounds. The most common pollutants in landfill biogas include volatile compounds of silicon, sulphur, phosphorus and chlorine. The aforementioned elements, as well as other metals, were found both in the deposits and in the engine oil. The paper presents detailed characteristics of the solid residues formed in selected parts of gas engines powered by landfill biogas. Its elemental composition and morphology were investigated in order to determine the structure and influence of these deposits. In order to better understand the observed features, selected analyses were also conducted for biogas, engine oil and the condensate generated during biogas dewatering. It was found that the content of individual elements in samples collected from the same part of the gas engine but sourced from various landfills vary. The occurrence of elements in deposits, e.g., Mg, Zn, P and Cr, depends on the location of sampling sites and the type of engine. It was also observed that the deposits formed in parts that come into contact with both biogas and engine oil contain Ca or Zn, which can be related to biogas pollutants as well as different oil additives. The presence of Al, Fe, Cu, Cr, Sn or Pb in selected motor oil samples can be explained by the penetration of metallic abrasives, which confirms the abrasive properties of the formed deposits. The analysis of the characteristic deposits may contribute to the selection of an appropriate landfill biogas purification technology, thus reducing the operating costs of energy cogeneration systems. Finally, we highlight challenges for biogas purification processes and anticipate the direction of future work.
RESUMEN
The aim of the research was to compare the chemical composition and morphology of the surface of the backsheet growing on the metallic and surface substrate growing already on the prepared mineral substrate. Moreover the aim of this study was also to analyze the dispersion of chemical elements on the cross-sections of deposits formed on parts of landfill biogas-driven engines. The chemical composition of extreme layers of mineral deposits extracted from the engine piston and their cross-sections from four pistons and one head was examined by SEM-EDS. The bottom side showed a much smaller heterogeneity of the topography of the surface than the topside. The chemical composition of the deposit bottom side it primarily S (41%), Si (34%) and Al (17%). In the case of the top side, the dominated of Ca (52%) with a relatively high share of S (32%) and Si (14%). The presence of P and Mg it was also found, but only on the bottom side, and the share of Fe and Zn only on the top side. In the case of cross-sections, Ca, S and Si were the dominant elements. In general, there were higher Si participations in the zone of the bottom layer with a downward trend to the top sheet. The mass shares of S and Ca were lower in the zone of the bottom layer with the upward trend to the top sheet, also undergoing fluctuation.
RESUMEN
This paper presents the determination of total iron, copper, zinc, chromium, nickel, lead, cadmium and mercury contents in the compost obtained from sorted municipal organic solid waste applying the following methods of sample mineralization: 40% hydrofluoric acid with preliminary incineration of a sample, a mixture of concentrated nitric(V) and chloric(VII) acids with preliminary incineration of organic matter and a mixture of nitric(V) and chloric(VII) acids without sample incineration. The speciation analysis of Tessier was used to estimate the bioavailability of the metals. Elution degrees of the mobile forms of the metals from the compost with 10% nitric(V) acid and 1 mol/dm(3) hydrochloric acid were compared. The contents of the elements in the eluates were determined applying atomic absorption spectrometry.
