Polycyclic Aromatic Hydrocarbons in Liquid Fuels Martin Staš, Tomáš Hlinčík Chemicke Listy, 2026 Polycyclic aromatic hydrocarbons (PAHs) are a group of aromatic compounds containing two or more fused aromatic rings. In liquid fuels, they are considered undesirable components, as some PAHs have proven carcinogenic effects, and their combustion contributes to the formation of harmful particulate matter, negatively impacting both the environment and human health. Among the liquid fuels discussed in this article, PAH content is monitored only in selected diesel-type fuels. The most commonly used diesel fuel in the Czech Republic and across the EU is B7 diesel, which contains a maximum of 7 % (V/V) bio-component and must comply with the requirements of the EN 590 standard. This standard sets a maximum PAH content of 8 % (m/m) for B7 diesel. For aviation fuels and automotive gasolines, no specific PAH limits are defined; the relevant standards only specify maximum permissible levels of total aromatic hydrocarbons.
Properties and Analysis of Solid Alternative Fuels Martin Staš, Zdeněk Beňo Paliva, 2025 As environmental challenges grow and efforts to reduce dependence on fossil fuels intensify, alternative fuels, including biofuels, are gaining attention. This article provides an overview of the technical requirements and testing methods for solid alternative fuels, focusing on two key types: solid biofuels and solid recovered fuel (SRF). It summarizes their essential properties, available testing methods, and the significance of individual analyses for evaluation and practical use. Solid biofuels, such as wood pellets, briquettes, and wood chips, play a vital role in the transition to renewable energy. They offer an eco-friendly alternative to fossil fuels, enhancing energy selfsufficiency and reducing CO₂ emissions. SRF, derived from processed waste, enables the efficient use of materials that would otherwise end up in landfills. However, strict quality control is necessary to ensure safe and environmentally responsible combustion, particularly regarding harmful substances. Both fuel types are crucial for sustainable energy management, supporting the circular economy and environmental protection.
Determination of Hydrocarbons in Gaseous and Liquid Fuels Martin Staš, Hugo Kittel, Pavel Šimáček Paliva, 2025 This article focuses on the analysis of hydrocarbon compounds in both conventional fossil fuels and alternative gaseous and liquid fuels. The main objective is to provide a comprehensive overview of the types of fuels that are monitored for total hydrocarbon content or for the presence of individual hydrocarbon compounds, the reasons for such monitoring, and the analytical methods used for this purpose. The text places particular emphasis on methods and parameters defined by technical standards, although in some cases it also addresses supplementary tests that are not directly required by normative regulations. The technical requirements and test methods for conventional fossil fuels and certain alternative fuels are defined in relevant technical standards, which establish a range of parameters essential for assessing fuel quality. Many of these monitored parameters have been discussed in detail in previous parts of this series of publications, which are dedicated to presenting common methods for evaluating both conventional and alternative fuels. The first four articles in this series focused on the determination of elements and non-hydrocarbon compounds in fuels [1], the evaluation of physical [2] and chemical [3] properties of fuels, and methods to assess the purity of fuels and combustion characteristics [4]. This current article presents the monitored parameters related to hydrocarbon content in both gaseous and liquid conventional and alternative fuels, as well as the analytical tests used for this purpose. It also addresses the reasons why monitoring hydrocarbon compounds in the respective fuels is important; specifically, the role that individual hydrocarbons play in terms of fuel quality, safety, or environmental impact. Among the test methods, the article focuses on those defined by technical standards, which form the standardized framework for evaluating various types of fuels. In some cases, additional or alternative procedures are also mentioned, which, although not standardized, can help expand knowledge about the composition and properties of fuels.
METODY HODNOCENÍ ČISTOTY A SPALOVACÍCH CHARAKTERISTIK MOTOROVÝCH PALIV Martin Staš, Hugo Kittel, Lukáš Matějovský, Pavel Šimáček Paliva, 2024 This article is the fourth in a series of articles aimed at introducing common methods for evaluating both conventional and alternative fuels. In previous articles, we focused on the determination of elements and non-hydrocarbon compounds, as well as the evaluation of physical and chemical properties. This article focuses on other not yet-discussed properties such as gum content, total impurities, ash content, carbonization residue, octane number, cetane number, and cetane index. The main goal of the article is to provide an overview of which fuels are used, why these properties are monitored, and what methods are used for this monitoring. Emphasis is placed mainly on standardized tests, but in some cases, additional tests not required by the standard are also discussed. Conventional and alternative fuels must meet the technical requirements defined by the relevant product standards. The fulfillment of these requirements is to ensure that, in addition to other properties, the relevant fuel will be of good quality and that the engine will not be damaged during its use. In addition to the technical requirements for fuels, the product standards also define the tests that are used to verify that the fuel meets the defined requirements. As mentioned above, this article is another in a series of articles aimed at presenting methods for evaluating both conventional and alternative fuels. In this article, we present an overview of the properties of fuels that have not yet been discussed in this series of articles. These are properties associated with the content of impurities present in the fuel (total impurities) or those impurities, or products that may arise during thermal stress on the fuel in the combustion system (ash content, carbonization residue, gum content). Furthermore, in this text, we will focus on the properties of fuels that characterize the fuel susceptibility to knocking (octane number) or the so-called hard running of the engine (cetane number and cetane index). In the article, we present for which fuels these properties are monitored, what are the limit values of these parameters and what are the reasons for their monitoring. We also present the testing methods that are used to determine these properties.
General Methods for the Analysis of Chemical Properties of Fuels Martin Staš, Hugo Kittel, Lukáš Matějovský, Eliška Vachková, Pavel Šimáček Paliva, 2024 This article is the third in a series of articles focused on presenting common methods for evaluating conventional and alternative fuels. The first two articles of the series were devoted to the determination of elements and non-hydrocarbon compounds in fuels [1]) and the determination of the physical properties of fuels [2]). This text presents an overview of the chemical properties determined for individual fuels. The chemical properties, acidity and alkalinity of fuels, content of unsaturated compounds, aniline point, water content, oxidation stability, and corrosive properties of fuels are presented in this article. The main goal of the article is to provide a comprehensive overview of which fuels are monitored, why they are monitored, and what methods are used for this monitoring. The emphasis is mainly on standardized parameters and tests, but in some cases, non-standardized tests are also discussed, or (additional) determinations not required by standards. For conventional and alternative fuels, several physical chemical, or other properties are used to evaluate the quality of these fuels. In this article, we present an overview of the chemical properties that are monitored for liquid and gaseous conventional and alternative fuels. These are acidity and alkalinity, content of unsaturated compounds, aniline point, water content, oxidation stability, and corrosive effects of fuels. In the article, we present the testing methods that are used to monitor these properties. Furthermore, we also present the reasons why these properties are monitored for individual fuels. Emphasis is placed on standardized parameters and tests, i.e., those prescribed by the relevant standards for individual fuels. However, parameters and alternative methods are also discussed, which are not prescribed by any standard for the respective fuels, but are supplementary determinations. The determination of elements and hydrocarbon and non-hydrocarbon compounds in fuels potentially falls within the scope of this article. However, since two separate articles [1] were devoted to these parameters, they will not be discussed here