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The use of fireworks as a sign of celebration is a common practice in many countries. During the last few years, this sector has been subjected to various social criticisms that have even led to a ban on their use in different places. One of the main causes is the environmental pollution they generate, due to emissions from combustion reactions associated with the use of pyrotechnic devices. Nitrate ester-based compounds as propellants are used in other solid rockets such as ammunition, but their use in pyrotechnics is currently limited to a small number of fireworks. This research analyses the substitution of black powder with nitrocellulose ([C6H7(NO2)3O5]n) as a propellant for aerial articles, as well as to the use of nitrocellulose as a perchlorate-free compound. In addition to achieving better clarity effects due to less smoke, the use of nitrocellulose reduces greenhouse gas emissions. However, this nitrogen-rich compound is more unstable, and the ignition sensitivity is higher. Therefore, the benefits and risks associated with this alternative compound need to be evaluated, but the evidence shown suggests a promising direction for the sustainable evolution of pyrotechnic compositions. [ABSTRACT FROM AUTHOR]

A thermochemical equilibrium model is formulated for wood chips downdraft gasification. Steady state ASPEN Plus simulator was utilized to evaluate producer gas composition and low heating value. Three cases are considered, due to mathematical model developed issues, and described in details. Experimental work was carried out within commercial small-scale CHP system where twelve beech wood samples were taken. Equivalence ratio is between 0.32 and 0.38 and air-fuel ratio ranges from 1.49 to 1.81, when gasifier capacity is optimal, at 250 kW. Mole fractions of CO2, H2, CO, CH4 and N2, in dry producer gas, are respectively, 16.06-17.64, 17.98-20.33, 13.71-17.26, 1.65-2.89 and 43.21-48.36. Multiple validation approach was applied for model verification. The results are in reasonable agreement with different literature sources (experimental work and modeling) and in a great agreement with the modified equilibrium model developed in Engineering Equation Solver found in the literature. Result deviations are explained by two major facts: wood downdraft gasification experiments are to a certain extent different and the model parameters could not be adjusted enough to fully minimize differences between model results. Predicted low heating value of dry producer gas is between 4.67-5.61 MJ/Nm3.

In the Republic of Serbia there are significant quantities of coffee and tire wastes that can be utilized as Solid Recovered Fuel (SRF) and used as an additional fuel for co–combustion with coal and biomass in energy production and cement industry sectors. Differences between SRF and base fuel are a cause of numerous problems in design of burners. The objective of this study was to determine the kinetic parameters for the thermochemical conversion of selected SRF using Simultaneous Thermal Analysis (STA). Samples of coffee and tire waste were used for the experimental tests. Thermal analysis was carried out in nitrogen atmosphere at three different heating rates 10, 15 and 20 K/min for each sample, while it was heated from room temperature up to 900°C. Two sample sizes x

Thermogravimetric and kinetic analysis of biomass and plastic co-pyrolysis can provide valuable inputs for a better understanding decomposition mechanisms. Such inputs are important for selecting the appropriate process conditions but can also be helpful for process modelling. This work investigates the properties of heterogenous sawdust mixed with polypropylene and polystyrene. Thermogravimetric analysis is conducted to determine the decomposition mechanism and kinetic parameters of investigated mixtures and to derive appropriate conclusions regarding their further utilisation potential. Co-pyrolysis was performed on mixtures with the following biomass/plastic ratios: 75-25%, 50-50%, 25-75%, over a temperature range of 30-550 ℃, at four heating rates 5, 10, 20, and 30 ℃/min, with pure argon as a carrier gas. The obtained results were then subjected to comprehensive kinetic and thermodynamic analysis. The primary goal was to determine effective activation energies using model-free methods, preexponential factors, and elementary thermodynamic parameters such as enthalpy, entropy, and free Gibbs energy changes. Finally, the influence of the heating rate and mixture composition was extensively investigated by analysing calculated parameters. [ABSTRACT FROM AUTHOR]

Recently, research in the field of coal combustion include impurities, specifically halogen elements (F, Cl, Br, I and At). Emission of chlorides and fluorides from the combustion depends on content and forms of these elements in coal, combustion process and emission reduction equipment. Examination of chlorides and fluorides content in coal and in flue gas is particularly important for design of flue gas desulphurisation plant, the integral part of the modern power plants which ensure meeting the requirements of SO2 emission regulations. In flue gas desulphurisation facilities, the presence of HCl may increase sorbent consumption and HCl and HF have the influence on wastewater treatment. This paper presents the results of chlorine and fluorine contents in domestic lignites and their concentration in flue gas. The aim of investigation was to determine the reference Cl and F concentrations in flue gas that would be used in the design of flue gas desulphurization plant.