Wood biomass fuels have become increasingly important in terms of achieving future sustainability... more Wood biomass fuels have become increasingly important in terms of achieving future sustainability targets regarding RES, especially to reduce GHG and the use of domestic energy sources, on other hand with these fuels the pulutant air emissions have to be addressed with great attention. Nowadays, air staging and flue gas recirculation are often used as a primary emission reduction measure in large scale biomass fuel fired boilers, but their combined application in small scale commercial wood pellet boilers is not so common. The implementation of this approach to the small scale burning devices can enable further development of small boilers, in order to achieve a more complete combustion and reduction of pollutant emissions, especially CO, NOx, and PM. In the presented work a comprehensive numerical and experimental study on the combustion parameters is performed, in order to determine the overall combustion properties. A commercial 32 kW small-scale hot water wood pellet boiler was ...
Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksi... more Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksida CO 2. Definirani su maseni i volumetrijski indeks i faktor emisije fosilnih goriva i izračunate njihove vrijednosti za najvažnija fosilna motorna goriva. Predstavljen je trend smanjenja specifične emisije CO 2 [g CO 2 /km] osobnih vozila za razdoblje 1995.-2020. koji su predložili proizvođači vozila. Analizirani su procesi pretvaranja primarne energije goriva u pogonskim motorima vozila i njihov utjecaj na stupanj iskorištenja motora i emisiju CO 2 vozila. Na osnovi rezultata statističke obrade podataka o deklariranom-tvorničkom i cestovnom specifičnom utrošku goriva [l/100 km] triju grupa vozila s benzinskim motorom, grupiranih po stapajnom obujmu motora, zbirno je ocijenjen utjecaj emisije CO na okoliš.
Some environmental aspects of meat and bone meal co-incineration in thermal power plant will be d... more Some environmental aspects of meat and bone meal co-incineration in thermal power plant will be discussed. A special attention will be dedicated to the pollutants formation possibilities during the combustion process and flue gas treatment. An accurate experimental analysis of all the residues has been performed and discussed, Some comparisons with other possible MBM treatment technologies, from the environmental point of view, have also been made.
Contemporary development of successful incineration devices is based on computational fluid dynam... more Contemporary development of successful incineration devices is based on computational fluid dynamics (CFD) simulation of reacting flow. Thus, the appropriate numerical simulation is engaged as a tool to develop new or to upgrade old incinerators. State-of-the-art commercial software packages enable reliable and accurate simulation of combustion processes including the ultimate analysis of the physical complete combustion conditions. Turbulence, temperature and residence time can be calculated and predicted by applying various macroscopic empirical fluid flow and combustion models. Direct accurate insight into processes inside the combustion chamber are however possible only through the practical CFD application. In our case the study of achievement difficulties of the complete combustion conditions in a two stage pilot incinerator has been numerically investigated by applying the CFD software package CFX 5.6. Initially all available combustion models were examined and the most appro...
Spent potlining (SPL) from aluminum reduction cell cathodes presents a major environmental concer... more Spent potlining (SPL) from aluminum reduction cell cathodes presents a major environmental concern in the primary aluminum industry. After laboratory tests it has been found that leaching cyanide and fluoride compounds present a major problem of SPL disposal. On the basis of the laboratory investigations, the possibilities of material and energy utilization of SPL have been studied. It has been concluded that SPL refractory material can be utilized directly in red brick manufacturing. A pilot test of the energy utilization of 25 tonnes of SPL carbon waste mixed with green petrol coke in a cement kiln has been performed. Additionally, the energy utilization possibility of SPL carbon waste in a coal thermal power plant have been investigated.
In-house bed model developed for realistic profiles of combustibles into freeboard. • Freeboard C... more In-house bed model developed for realistic profiles of combustibles into freeboard. • Freeboard CFD based on the in-house bed model is reliable for further optimisation. • Impact of in-bed conversion models restricted to the vicinity of the fuel bed. • A simplified bed model still useful for a rough analysis of freeboard combustion. • A more general in-bed conversion model beneficial for both fuel bed and freeboard.
Optimal geometric and process parameters related to air staging, which ultimately lead to lower p... more Optimal geometric and process parameters related to air staging, which ultimately lead to lower pollutant formation and a higher thermal efficiency, can be found by utilisation of the CFD simulation method. Simplified and computationally efficient methods for the simulation of complex phenomena which occur in a biomass boiler can, therefore, be of great use, provided they offer reliable and reasonably accurate predictions. A previously developed and validated Computational Fluid Dynamics combustion simulation methodology for largescale waste to energy grate-fired boilers is modified and implemented for the case of a commercial 32 kW wood pellet hot water boiler. An experimental investigation is performed in order to determine process parameters used in the fuel conversion modelling, case setup and, finally, to enable the validation of the numerical modelling approach. The solid fuel conversion is modelled by a coupled empirical 1D bed model which predicts the composition of the combustible gas mixture released from the fuel bed into the freeboard. Compared to the originally proposed fuel bed conversion model, the modified model includes partial char and volatile oxidation, and relies on gas temperatures measured above the fuel bed. Using the modified fuel bed conversion model, several cases were simulated in order to find the most appropriate parameters of the combined finite rate-eddy dissipation combustion model. Results show that by implementing the modified fuel bed conversion model that relies on measurements, reasonably accurate predictions can be achieved of the gas temperature in the combustion chamber and CO concentration at the flue gas outlet.
Abstract An effective air staging strategy is of great importance for achieving low emissions and... more Abstract An effective air staging strategy is of great importance for achieving low emissions and sensible heat losses through flue gas extraction. In cases where a commercially available system needs to be optimised, often the only viable measure is the modification of process parameters. In this work, the aim is to (1) Discover a combination of the most suitable process parameters based on a multi-criteria decision-making method and (2) To unveil relevant correlations between the two process parameters under study (PA/SA ratio and excess air), emissions and combustion temperatures. A modified commercial small-scale hot water wood pellet boiler was installed into a laboratory heating system. Nine different cases have been addressed within a parametric study, differing in the PA/SA ratio and overall excess air. Emissions, temperatures inside the combustion chamber and the flow rate of air entering the combustion chamber were measured. A low PA/SA ratio of 0.53 (54.7% reduction from factory settings), combined with a low O2 concentration in the flue gases of 5.26% (39.8% reduction from factory settings), and the elimination of infiltration air resulted in a simultaneous reduction of NOx and CO emissions by 14.4% and 93.9% respectively and a flue gas sensible heat loss reduction of 31.6%.
The applicability is studied of a simplified equilibrium model for prediction of the composition ... more The applicability is studied of a simplified equilibrium model for prediction of the composition and quality of producer gas from gasification of different waste. A simplified equilibrium model of stoichiometric type based on system thermodynamic equilibrium has been developed in the form of a stand-alone computer application. Standard numerical methods have been implemented for solving the mathematical problem formulation. The model`s predicted results have been compared with the published results for biomass and some waste types - municipal solid wastes and refuse derived fuels. Results are included for a bubbling fluidized bed and downdraft fixed bed allothermal gasification, also for catalytic supported gasification. Producer gas predictions by calibrated and non-calibrated versions of the simplified equilibrium model have been studied. The accuracy of these predictions has been evaluated. The results obtained by the simplified equilibrium model have confirmed that such model is...
The International Conference on Applied Mechanics and Mechanical Engineering, 2012
Waste-to-energy process is essential part of modern and future integrated waste management soluti... more Waste-to-energy process is essential part of modern and future integrated waste management solutions. The waste-to-energy process using municipal solid waste as a fuel was studied in detail for complete understanding of these phenomena especially in terms of energy conversion into electrical power and the influence on the environment. The goal of our research was to substantially upgrade the waste-toenergy process from grate combustion into gasification for more efficient electrical power production and even lower the negative influence on the environment of the whole process. Our research team has remodeled inclined grate combustion chamber into gasification reactor. The reactor is possible to operate in updraft or downdraft mode enabling the more adequate process adoption based on the input waste characteristics. The produced synthetic gas has relatively high calorific value and temperature, both can be turned into useful heat and electrical power.
This paper presents the most appropriate numerical approach for investigation of the ignition phe... more This paper presents the most appropriate numerical approach for investigation of the ignition phenomena of the premixed confined combustion in a condensing boiler. A transient simulation with the coupling of the burning velocity model was sufficient enough to describe fully the phenomena that are responsible for the ignition sequence and the flame stabilization, representing most of the actual ignition problems in general. Detailed simulation investigation with the ignition model leads to better comprehension of the whole flame stabilization process and, as a consequence, it facilitates the optimization potential of the global ignition process in boilers. Four different ignition power loads were observed in the investigation. Also, the ratio between oxidizer (air in our case) and the fuel (Methane) was based on the normal combustion process for the described condensing boiler. The numerical results were validated with the experimental set up and testing. Results comparison shows very good correlation of numerical simulation with the experimental case. The ignition times both tested and simulated, that have a significant impact on flame stabilization, are in very good correlation. Also, very good correlations were obtained between the pressure profiles of the numerical and experimental studies.
Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In sp... more Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In spite of the recent breakthrough in integration of advanced secondary air systems in grate boilers, grate-firing technology needs to be advanced for higher efficiency and lower emissions. In this paper, innovative staging of combustion air and recycled flue gas in a 13 MW th waste wood-fired grate boiler is comprehensively studied based on a numerical model that has been previously validated. In particular, the effects of the jet momentum, position and orientation of the combustion air and recycled flue gas streams on in-furnace mixing, combustion and pollutant emissions from the boiler are examined. It is found that the optimized air and recycled flue gas jets remarkably enhance mixing and heat transfer, result in a more uniform temperature and velocity distribution, extend the residence time of the combustibles in the hot zone and improve burnout in the boiler. Optimizing the air and recycled flue gas jet configuration can reduce carbon monoxide emission from the boiler by up to 86%, from the current 41.0 ppm to 5.7 ppm. The findings of this study can serve as useful guidelines for novel design and optimization of the combustion air supply and flue gas recycling for grate boilers of this type.
Renewable energy production, storage and utilization has been studied in connection with fluctuat... more Renewable energy production, storage and utilization has been studied in connection with fluctuating renewable power production and demand. The coupling has been considered of surplus renewable power with sewage sludge gasification and renewable syngas storage. High quality syngas produced with power support can be introduced into a gas distribution network or stored and utilized on site. Both systems enable gas consumption at power and heat demand periods. The efficiency of power conversion to syngas produced from high moisture sewage sludge has been studied using a developed equilibrium thermodynamic model for the gasification process providing the calculated prediction of the syngas amount and composition. Furthermore, the total energy efficiency has been studied of the syngas production and utilization system. The results show that the optimum scenario to get syngas suitable to introduce into a natural gas distribution network would be to gasify sewage sludge with 35-40 wt.% moisture, while the optimal parameter for syngas to be valorized onsite is, in terms of efficiency, with SS dried to 20 wt.% of moisture content. In the first scenario, a little more power is produced from stored gas in a natural gas distribution network than consumed, and almost twice as much is produced with on-site production, storage and utilization. The study has showed a technically feasible management option for energy production, storage and consumption with available technologies and infrastructure.
The interdependence between IC engine development and fuel/lubricant quality has existed, ever si... more The interdependence between IC engine development and fuel/lubricant quality has existed, ever since the first engine was born. In fact the first engine was invented and designed for using explicitly only a definite type of fuel. This has required a continuous and strong cooperation between engineers, researchers and other experts of both branches of industries. In this paper a short review of IC engine development during the last century is presented first, and the requirements on IC engine performance in the near future are listed. In continuation only a few of most important physical and chemical properties determining the quality of vehicular engine fuels have been analyzed and discussed: octane and cetane number, fuel chemical composition, fuel S, N, P and N, mainly from the stand point of their influence on IC engine effective parameters, operating engine performance and pollutant emissions.
Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksi... more Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksida CO 2. Definirani su maseni i volumetrijski indeks i faktor emisije fosilnih goriva i izračunate njihove vrijednosti za najvažnija fosilna motorna goriva. Predstavljen je trend smanjenja specifične emisije CO 2 [g CO 2 /km] osobnih vozila za razdoblje 1995.-2020. koji su predložili proizvođači vozila. Analizirani su procesi pretvaranja primarne energije goriva u pogonskim motorima vozila i njihov utjecaj na stupanj iskorištenja motora i emisiju CO 2 vozila. Na osnovi rezultata statističke obrade podataka o deklariranom-tvorničkom i cestovnom specifičnom utrošku goriva [l/100 km] triju grupa vozila s benzinskim motorom, grupiranih po stapajnom obujmu motora, zbirno je ocijenjen utjecaj emisije CO na okoliš.
Thermal treatment of sewage sludge-one of possible disposal methods Waste water treatment is a st... more Thermal treatment of sewage sludge-one of possible disposal methods Waste water treatment is a standard process in developed countries. It is intended to minimize the influence of waste water on the environment. The treatment process produces various remains that are generally called sewage sludge. In general, the remaining material is treated physically to dewater the sludge to reduce the volume and mass before disposal. This treated sewage sludge has around 25% of dry solids. The chemical and physical properties of the sewage sludge have to be monitored to determine the correct method of disposal. If the sewage sludge contains higher concentrations of heavy metals the only method for the disposal is thermal treatment. This article will present possible technologies for sewage sludge thermal treatment and the experience of Slovene waste thermal treatment plant that incinerates sewage sludge.
Wood biomass fuels have become increasingly important in terms of achieving future sustainability... more Wood biomass fuels have become increasingly important in terms of achieving future sustainability targets regarding RES, especially to reduce GHG and the use of domestic energy sources, on other hand with these fuels the pulutant air emissions have to be addressed with great attention. Nowadays, air staging and flue gas recirculation are often used as a primary emission reduction measure in large scale biomass fuel fired boilers, but their combined application in small scale commercial wood pellet boilers is not so common. The implementation of this approach to the small scale burning devices can enable further development of small boilers, in order to achieve a more complete combustion and reduction of pollutant emissions, especially CO, NOx, and PM. In the presented work a comprehensive numerical and experimental study on the combustion parameters is performed, in order to determine the overall combustion properties. A commercial 32 kW small-scale hot water wood pellet boiler was ...
Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksi... more Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksida CO 2. Definirani su maseni i volumetrijski indeks i faktor emisije fosilnih goriva i izračunate njihove vrijednosti za najvažnija fosilna motorna goriva. Predstavljen je trend smanjenja specifične emisije CO 2 [g CO 2 /km] osobnih vozila za razdoblje 1995.-2020. koji su predložili proizvođači vozila. Analizirani su procesi pretvaranja primarne energije goriva u pogonskim motorima vozila i njihov utjecaj na stupanj iskorištenja motora i emisiju CO 2 vozila. Na osnovi rezultata statističke obrade podataka o deklariranom-tvorničkom i cestovnom specifičnom utrošku goriva [l/100 km] triju grupa vozila s benzinskim motorom, grupiranih po stapajnom obujmu motora, zbirno je ocijenjen utjecaj emisije CO na okoliš.
Some environmental aspects of meat and bone meal co-incineration in thermal power plant will be d... more Some environmental aspects of meat and bone meal co-incineration in thermal power plant will be discussed. A special attention will be dedicated to the pollutants formation possibilities during the combustion process and flue gas treatment. An accurate experimental analysis of all the residues has been performed and discussed, Some comparisons with other possible MBM treatment technologies, from the environmental point of view, have also been made.
Contemporary development of successful incineration devices is based on computational fluid dynam... more Contemporary development of successful incineration devices is based on computational fluid dynamics (CFD) simulation of reacting flow. Thus, the appropriate numerical simulation is engaged as a tool to develop new or to upgrade old incinerators. State-of-the-art commercial software packages enable reliable and accurate simulation of combustion processes including the ultimate analysis of the physical complete combustion conditions. Turbulence, temperature and residence time can be calculated and predicted by applying various macroscopic empirical fluid flow and combustion models. Direct accurate insight into processes inside the combustion chamber are however possible only through the practical CFD application. In our case the study of achievement difficulties of the complete combustion conditions in a two stage pilot incinerator has been numerically investigated by applying the CFD software package CFX 5.6. Initially all available combustion models were examined and the most appro...
Spent potlining (SPL) from aluminum reduction cell cathodes presents a major environmental concer... more Spent potlining (SPL) from aluminum reduction cell cathodes presents a major environmental concern in the primary aluminum industry. After laboratory tests it has been found that leaching cyanide and fluoride compounds present a major problem of SPL disposal. On the basis of the laboratory investigations, the possibilities of material and energy utilization of SPL have been studied. It has been concluded that SPL refractory material can be utilized directly in red brick manufacturing. A pilot test of the energy utilization of 25 tonnes of SPL carbon waste mixed with green petrol coke in a cement kiln has been performed. Additionally, the energy utilization possibility of SPL carbon waste in a coal thermal power plant have been investigated.
In-house bed model developed for realistic profiles of combustibles into freeboard. • Freeboard C... more In-house bed model developed for realistic profiles of combustibles into freeboard. • Freeboard CFD based on the in-house bed model is reliable for further optimisation. • Impact of in-bed conversion models restricted to the vicinity of the fuel bed. • A simplified bed model still useful for a rough analysis of freeboard combustion. • A more general in-bed conversion model beneficial for both fuel bed and freeboard.
Optimal geometric and process parameters related to air staging, which ultimately lead to lower p... more Optimal geometric and process parameters related to air staging, which ultimately lead to lower pollutant formation and a higher thermal efficiency, can be found by utilisation of the CFD simulation method. Simplified and computationally efficient methods for the simulation of complex phenomena which occur in a biomass boiler can, therefore, be of great use, provided they offer reliable and reasonably accurate predictions. A previously developed and validated Computational Fluid Dynamics combustion simulation methodology for largescale waste to energy grate-fired boilers is modified and implemented for the case of a commercial 32 kW wood pellet hot water boiler. An experimental investigation is performed in order to determine process parameters used in the fuel conversion modelling, case setup and, finally, to enable the validation of the numerical modelling approach. The solid fuel conversion is modelled by a coupled empirical 1D bed model which predicts the composition of the combustible gas mixture released from the fuel bed into the freeboard. Compared to the originally proposed fuel bed conversion model, the modified model includes partial char and volatile oxidation, and relies on gas temperatures measured above the fuel bed. Using the modified fuel bed conversion model, several cases were simulated in order to find the most appropriate parameters of the combined finite rate-eddy dissipation combustion model. Results show that by implementing the modified fuel bed conversion model that relies on measurements, reasonably accurate predictions can be achieved of the gas temperature in the combustion chamber and CO concentration at the flue gas outlet.
Abstract An effective air staging strategy is of great importance for achieving low emissions and... more Abstract An effective air staging strategy is of great importance for achieving low emissions and sensible heat losses through flue gas extraction. In cases where a commercially available system needs to be optimised, often the only viable measure is the modification of process parameters. In this work, the aim is to (1) Discover a combination of the most suitable process parameters based on a multi-criteria decision-making method and (2) To unveil relevant correlations between the two process parameters under study (PA/SA ratio and excess air), emissions and combustion temperatures. A modified commercial small-scale hot water wood pellet boiler was installed into a laboratory heating system. Nine different cases have been addressed within a parametric study, differing in the PA/SA ratio and overall excess air. Emissions, temperatures inside the combustion chamber and the flow rate of air entering the combustion chamber were measured. A low PA/SA ratio of 0.53 (54.7% reduction from factory settings), combined with a low O2 concentration in the flue gases of 5.26% (39.8% reduction from factory settings), and the elimination of infiltration air resulted in a simultaneous reduction of NOx and CO emissions by 14.4% and 93.9% respectively and a flue gas sensible heat loss reduction of 31.6%.
The applicability is studied of a simplified equilibrium model for prediction of the composition ... more The applicability is studied of a simplified equilibrium model for prediction of the composition and quality of producer gas from gasification of different waste. A simplified equilibrium model of stoichiometric type based on system thermodynamic equilibrium has been developed in the form of a stand-alone computer application. Standard numerical methods have been implemented for solving the mathematical problem formulation. The model`s predicted results have been compared with the published results for biomass and some waste types - municipal solid wastes and refuse derived fuels. Results are included for a bubbling fluidized bed and downdraft fixed bed allothermal gasification, also for catalytic supported gasification. Producer gas predictions by calibrated and non-calibrated versions of the simplified equilibrium model have been studied. The accuracy of these predictions has been evaluated. The results obtained by the simplified equilibrium model have confirmed that such model is...
The International Conference on Applied Mechanics and Mechanical Engineering, 2012
Waste-to-energy process is essential part of modern and future integrated waste management soluti... more Waste-to-energy process is essential part of modern and future integrated waste management solutions. The waste-to-energy process using municipal solid waste as a fuel was studied in detail for complete understanding of these phenomena especially in terms of energy conversion into electrical power and the influence on the environment. The goal of our research was to substantially upgrade the waste-toenergy process from grate combustion into gasification for more efficient electrical power production and even lower the negative influence on the environment of the whole process. Our research team has remodeled inclined grate combustion chamber into gasification reactor. The reactor is possible to operate in updraft or downdraft mode enabling the more adequate process adoption based on the input waste characteristics. The produced synthetic gas has relatively high calorific value and temperature, both can be turned into useful heat and electrical power.
This paper presents the most appropriate numerical approach for investigation of the ignition phe... more This paper presents the most appropriate numerical approach for investigation of the ignition phenomena of the premixed confined combustion in a condensing boiler. A transient simulation with the coupling of the burning velocity model was sufficient enough to describe fully the phenomena that are responsible for the ignition sequence and the flame stabilization, representing most of the actual ignition problems in general. Detailed simulation investigation with the ignition model leads to better comprehension of the whole flame stabilization process and, as a consequence, it facilitates the optimization potential of the global ignition process in boilers. Four different ignition power loads were observed in the investigation. Also, the ratio between oxidizer (air in our case) and the fuel (Methane) was based on the normal combustion process for the described condensing boiler. The numerical results were validated with the experimental set up and testing. Results comparison shows very good correlation of numerical simulation with the experimental case. The ignition times both tested and simulated, that have a significant impact on flame stabilization, are in very good correlation. Also, very good correlations were obtained between the pressure profiles of the numerical and experimental studies.
Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In sp... more Grate-fired boilers are commonly used to burn biomass/wastes for heat and power production. In spite of the recent breakthrough in integration of advanced secondary air systems in grate boilers, grate-firing technology needs to be advanced for higher efficiency and lower emissions. In this paper, innovative staging of combustion air and recycled flue gas in a 13 MW th waste wood-fired grate boiler is comprehensively studied based on a numerical model that has been previously validated. In particular, the effects of the jet momentum, position and orientation of the combustion air and recycled flue gas streams on in-furnace mixing, combustion and pollutant emissions from the boiler are examined. It is found that the optimized air and recycled flue gas jets remarkably enhance mixing and heat transfer, result in a more uniform temperature and velocity distribution, extend the residence time of the combustibles in the hot zone and improve burnout in the boiler. Optimizing the air and recycled flue gas jet configuration can reduce carbon monoxide emission from the boiler by up to 86%, from the current 41.0 ppm to 5.7 ppm. The findings of this study can serve as useful guidelines for novel design and optimization of the combustion air supply and flue gas recycling for grate boilers of this type.
Renewable energy production, storage and utilization has been studied in connection with fluctuat... more Renewable energy production, storage and utilization has been studied in connection with fluctuating renewable power production and demand. The coupling has been considered of surplus renewable power with sewage sludge gasification and renewable syngas storage. High quality syngas produced with power support can be introduced into a gas distribution network or stored and utilized on site. Both systems enable gas consumption at power and heat demand periods. The efficiency of power conversion to syngas produced from high moisture sewage sludge has been studied using a developed equilibrium thermodynamic model for the gasification process providing the calculated prediction of the syngas amount and composition. Furthermore, the total energy efficiency has been studied of the syngas production and utilization system. The results show that the optimum scenario to get syngas suitable to introduce into a natural gas distribution network would be to gasify sewage sludge with 35-40 wt.% moisture, while the optimal parameter for syngas to be valorized onsite is, in terms of efficiency, with SS dried to 20 wt.% of moisture content. In the first scenario, a little more power is produced from stored gas in a natural gas distribution network than consumed, and almost twice as much is produced with on-site production, storage and utilization. The study has showed a technically feasible management option for energy production, storage and consumption with available technologies and infrastructure.
The interdependence between IC engine development and fuel/lubricant quality has existed, ever si... more The interdependence between IC engine development and fuel/lubricant quality has existed, ever since the first engine was born. In fact the first engine was invented and designed for using explicitly only a definite type of fuel. This has required a continuous and strong cooperation between engineers, researchers and other experts of both branches of industries. In this paper a short review of IC engine development during the last century is presented first, and the requirements on IC engine performance in the near future are listed. In continuation only a few of most important physical and chemical properties determining the quality of vehicular engine fuels have been analyzed and discussed: octane and cetane number, fuel chemical composition, fuel S, N, P and N, mainly from the stand point of their influence on IC engine effective parameters, operating engine performance and pollutant emissions.
Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksi... more Prikazan je utjecaj motornih goriva i pogonskih motora osobnih vozila na emisiju ugljičnog dioksida CO 2. Definirani su maseni i volumetrijski indeks i faktor emisije fosilnih goriva i izračunate njihove vrijednosti za najvažnija fosilna motorna goriva. Predstavljen je trend smanjenja specifične emisije CO 2 [g CO 2 /km] osobnih vozila za razdoblje 1995.-2020. koji su predložili proizvođači vozila. Analizirani su procesi pretvaranja primarne energije goriva u pogonskim motorima vozila i njihov utjecaj na stupanj iskorištenja motora i emisiju CO 2 vozila. Na osnovi rezultata statističke obrade podataka o deklariranom-tvorničkom i cestovnom specifičnom utrošku goriva [l/100 km] triju grupa vozila s benzinskim motorom, grupiranih po stapajnom obujmu motora, zbirno je ocijenjen utjecaj emisije CO na okoliš.
Thermal treatment of sewage sludge-one of possible disposal methods Waste water treatment is a st... more Thermal treatment of sewage sludge-one of possible disposal methods Waste water treatment is a standard process in developed countries. It is intended to minimize the influence of waste water on the environment. The treatment process produces various remains that are generally called sewage sludge. In general, the remaining material is treated physically to dewater the sludge to reduce the volume and mass before disposal. This treated sewage sludge has around 25% of dry solids. The chemical and physical properties of the sewage sludge have to be monitored to determine the correct method of disposal. If the sewage sludge contains higher concentrations of heavy metals the only method for the disposal is thermal treatment. This article will present possible technologies for sewage sludge thermal treatment and the experience of Slovene waste thermal treatment plant that incinerates sewage sludge.
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