Air-cooled condensers in thermal power plants have recently become increasingly popular. Besides all the advantages they have, like no demands for water supply on the plant site and no need for taking care of environmental regulations, they also have some serious disadvantages. One of the biggest disadvantages air-cooled condensers do have is precisely the nature of the Earth?s atmosphere being their low temperature reservoir. Low density and low heat capacity of the air as the cooling medium combined with extremely stochastic behavior of the atmosphere itself put some serious challenges in front of the air-cooled condenser?s proper and steady functioning. In this paper, the operating parameters of the air-cooled condenser in the chosen thermal power plant were investigated to gain a clearer insight into the influence of the atmospheric changes on its entropy generation and consequently on its efficiency. Also, the acquired results were further proposed as a starting point for potential optimization of the process inside the device.

Most air pollution originates from combustion processes, so it is important to make quantitative as well as qualitative analysis, as the sources of pollution can be stochastic – especially for road traffic. The point of our study is to better determine road traffic as one of the largest pollution sources in the city of Niš, Serbia. The research was conducted at several locations in the city that represent all of the main roads across the city. Parameters considered in the study were traffic frequency, vehicle type, annual vehicle mileage in the city, and average vehicle velocity. Besides these parameters, roadside CO₂ concentration was measured for evaluation. These data were used as the input for the COPERT methodology of air pollutant emissions calculation from road transport. On the basis of these data, annual CO₂ emissions and major pollutants were calculated, as well as the specific average emissions on roads. According to this, a classification of roads in respect to their specific average emissivity is given at the end of this paper.

As sustainable energy practices become more popular, biomass-fired boilers are becoming a choice over traditional fossil fuel models due to their eco-friendly nature. Despite their environmental advantages, biomass boilers still emit pollutants like particulate matter (PM), sulfur dioxide (SO2), nitrogen oxides (NOX), and carbon monoxide (CO), posing environmental concerns. To mitigate these emissions, modern biomass-fired boilers often incorporate Flue Gas Recirculation (FGR). This research focuses on a 14 MW biomass-fired boiler operating with a 20% FGR rate, examining three scenarios: two with varying FGR levels and one without FGR. The analysis reveals a connection between emission reduction via FGR and boiler efficiency maintenance. Additionally, it suggests optimizing FGR levels to boost boiler efficiency. The study presents a comprehensive approach to effectively implement FGR in biomass-fired boilers while ensuring acceptable efficiency levels. NOX emissions were analyzed using combustion simulation software and the Zeldovich method to estimate thermal NOX production.

This study delves into refining the ideal gas viscosity equation by introducing amendments that account for temperature variations and critical temperature ratios across diverse ideal gases. The investigation involves comparing the adjusted formula with empirical data obtained from various gases under extreme conditions, including ultra-critical temperatures and near-critical points like for water and carbon dioxide. The primary objective is to enhance the equation's accuracy and applicability. The research proposes novel modifications integrating a temperature-dependent dumping coefficient and a redefined temperature exponent. These adjustments aim to capture gas behavior across a wider spectrum of temperatures, pressures, and gas compositions. Building upon foundational works in gas dynamics and molecular theory, this study bridges the gap between theoretical formulations and empirical observations. To validate these modifications, empirical data from gases under diverse conditions, including ultra-critical temperatures and mixtures, were utilized. Notably, the study's focus extends to analyzing gases under extreme conditions, highlighting the formula's improved predictive capability, and assessing its performance against complex gas mixtures using software-generated data. The findings reveal that these proposed adjustments significantly enhance the equation's alignment with real-world observations. Specifically, the analysis showcases improved predictive accuracy, especially in extreme gas conditions, and promising results when evaluating complex gas mixtures. These modifications offer a more comprehensive framework for estimating viscosity across a broad range of gas types and conditions, thereby enhancing the predictive power of the ideal gas viscosity equation.

Fluidization has become a subject of wide interest in chemical engineering during the past few decades. This paper presents one part of the results of the kinetics research into the drying of fine grained material in a two-component fluidized bed. A review of theoretical and experimental investigations of aerodynamics of the fluidized bed and minimum fluidization velocity of particles are given, with a special insight into two-component fluidized beds (binary mixture), as well as the basics of heat and material transfer through a fluidized bed. The interaction between complex hydrodynamics and transfer mechanisms complicates the analysis, design and prediction of gas-fluidized-bed processes. Based on experimental investigations, where zeolits was used as a representative of fine grained material, and polyethylene as a representative of the inert material (another component), an analysis of the influence of working parameters on drying in a two-component fluidized bed has been performed. Before that, the minimum velocities for two-component fluidized bed with particles of different sizes and densities were studied experimentally. Also, the ability of elutriation of fine particles from the fluidized bed is described. The present paper deals with the experimental results on the influence of the considered parameters, such as the drying agent temperature and the mass ratio of zeolite and the inert material on the drying curve. The participation of the inert material can considerably increase the intensity of heat and material transfer in the flui dized bed.