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This paper presents an innovative mathematical model of solid fuel gasification, which is not described in the available literature. The calculation of the components of the heterogeneous phase (including both solid and gaseous phases) as well as the calculation of the homogeneous phase (only gaseous components) is based on the balance of the total amounts of carbon, oxygen, hydrogen, and nitrogen entering the reactor space. Additionally, this paper introduces a new method for calculating the composition of the gaseous phase, based on reducing the heterogeneous mixture (composed of solid and gaseous phases) to a homogeneous gaseous phase. This approach to calculating the gaseous phase composition in the solid fuel gasification process has not been found by the authors in the cited literature. This paper also presents a model for calculating the heterogeneous and gaseous phases using the number of moles that participate in the assumed chemical reactions of the solid fuel gasification process. This approach to calculating the composition of the heterogeneous and gaseous phases of the solid fuel gasification process is also not represented in the cited literature. For comparison with the literature data, municipal solid waste (MSW) and cashew nut shell (Cashew Shell Char (CNSC)) were used as fuels in the calculation of gasification composition. The results of the calculation of the gaseous phase composition using the model presented in the paper show good agreement with the data from the literature. The calculation of the composition of the heterogeneous mixture during the steam gasification of MSW (α = 0.4) shows the presence of a solid phase (carbon) up to approximately 735 °C. At that temperature, the synthetic gas contains only gaseous components: CO = 33.10%, H2 = 52.70%, CH4 = 2.54%, CO2 = 4.97, H2O = 5.93% and N2 = 0.76%. Increasing the temperature above 735 °C eliminates the solid phase from the equilibrium mixture. The literature data on solid fuel gasification generally do not consider the proportion of the solid phase (carbon) in the equilibrium mixture. To satisfy the material balance at the input and output of the gasification reactor, it is necessary to determine the proportion of the solid phase (carbon) in the equilibrium mixture. Since the proportion of the solid phase (carbon) in the heterogeneous equilibrium mixture can only be determined through measurement, the development and application of a mathematical model in engineering practice is of great importance, so this developed model can be considered a useful tool for simulating the influence of process parameters on gas characteristics. [ABSTRACT FROM AUTHOR]

Crop residues could provide a local, sustainable, and low-cost solid fuel alternative to woody biomass for heat supply in the agricultural community. However, utilization of crop residues on a small scale is associated with increased pollutant emissions, as well as ash-related operational problems. There is ongoing research on fuel conditioning measures, such as fuel leaching, fuel blending, and using mineral additives, as a manner to mitigate these issues. The purpose of this study is to investigate the applicability of additives in the combustion of crop residues under everyday conditions. To this end, wheat straw pellets were combusted in a 30 kW boiler with and without additives (kaolinite and MgO, 2 wt. % and 4 wt. %). Carbon monoxide (CO) and particulate matter (PM) emissions have been monitored during combustion experiments, as well as changes in bottom ash behavior and composition. The results have shown that additives slightly decrease the heating value of the fuel (3%–6%). During experiments with additized wheat straw pellets, higher emissions of CO were observed. Combustion of pure not additized wheat straw pellets resulted in a PM emission of 568 mg/Nm3, which decreased with additives. Both researched additives increase the four characteristic ash deformation temperatures. [ABSTRACT FROM AUTHOR]

Flows of transformer, motor and other types of oil in electric power distribution system require certain analyses over the safe handling and efficient management of oil flow in the above mentioned system for not only the purpose of environmental protection but the integration with other forms of protection and the implementation of adequate protection measures. The set of system activities is to be realized in the distribution of electrical energy and other complex activities, which includes continuous education of all participants in charge of monitoring, control and management of various types and quantities of the flows of waste and new oils, creation and update of the internal documents, collection and temporary storage of waste oils within the organizational units and final disposal of waste. The study presents the analysis and treatment of transformer, motor and other oils in the MH "ERS" ZEDP "Elektro-Bijeljina" joint-stock company Bijeljina, which shows the types, quantities and flows of oil, treatment and solution methodologies, including other activities to be implemented in the electricity distribution system in developing countries. [ABSTRACT FROM AUTHOR]

Safe handling and manipulation of transformer oil in the electrical energy distribution and other sectors are to be realised in a manner and procedure that will not pose a risk of water, soil or air pollution for the protection of environment, life and health of people. Implementation of the necessary preventive and corrective measures for environmental protection, fire protection, safety and health at work is, among other things, mandatory, including the respect for and the realisation of legal provisions, standards and regulations for the purpose of safe and optimal treatment and management of transformer oil, and prevention or reduction of negative impact on the environment and human health. The study presents the sources of transformer oil, testing and determining the trend of transformer oil's important features in the exploitation, with particular emphasis on potential negative impact on the environment, safety and health, therefore the results, recommendations and conclusions are given. [ABSTRACT FROM AUTHOR]

Combustion of wheat straw was investigated in a fixed-bed reactor for two air flow rates, 1,151 and 2,125 kg/m2h. Measured temperatures, mass loss, and gas composition were used to evaluate the combustion characteristics in terms of ignition front speed, burning rate, and quality of combustion in general. At lower value of air flow rate difference between the ignition rate and burning rate was significant, which can be easily noticed by the measurement results. At higher value of air flow rate, there was still a small difference between the ignition and burning rate, while the content of oxygen in the flue gas was 10%, which leads to the conclusion that a change in the method of delivering the combustion air is necessary. [ABSTRACT FROM PUBLISHER]