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Robert Junga
Department of Thermal Engineering and Industrial Facilities, Faculty of Mechanical Engineering, Opole University of Technology, 5 Mikołajczyka Str., 45-271 Opole, Poland

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Journal article
Published: 08 July 2021 in Energies
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In this study, the combustion of olive byproducts was investigated using the TG-FTIR technique. Different types of olive biomass were considered: twigs, leaves, olive-mill waste from the two-phase decanting method, and wastewater from the three-phase system. The reaction regions, ignition, and burnout temperatures at different heating rates were determined using TG/DTG analysis and the thermogravimetry results. Comprehensive combustion, ignition, burnout, and flammability indexes were also calculated. The highest combustion index values were obtained for waste from the three-phase system, followed by the two-phase decanting method, then with leaves and small twigs. The order of the index values indicated that the sample from the three-phase process ignited more quickly and yielded faster. The changes in activation energy calculated using different model-free isoconversional methods—Friedman, Ozawa–Flynn–Wall, and Kissinger–Akahira–Sunose—fell within the range of 130–140 kJ/kmol. FTIR analyses presented differences in the exhaust gas composition for specific combustion temperature ranges.

ACS Style

Małgorzata Wzorek; Robert Junga; Ersel Yilmaz; Bohdan Bozhenko. Thermal Decomposition of Olive-Mill Byproducts: A TG-FTIR Approach. Energies 2021, 14, 4123 .

AMA Style

Małgorzata Wzorek, Robert Junga, Ersel Yilmaz, Bohdan Bozhenko. Thermal Decomposition of Olive-Mill Byproducts: A TG-FTIR Approach. Energies. 2021; 14 (14):4123.

Chicago/Turabian Style

Małgorzata Wzorek; Robert Junga; Ersel Yilmaz; Bohdan Bozhenko. 2021. "Thermal Decomposition of Olive-Mill Byproducts: A TG-FTIR Approach." Energies 14, no. 14: 4123.

Journal article
Published: 06 July 2020 in Applied Thermal Engineering
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The aim of research is to provide a comprehensive view of the combustion process of coal with a liquid fuel additive. The studies were carried out in laboratory conditions and on low and high power boilers which are usually used in households and local district heating plants. TGA/DSC analysis shows that the additive decreases the ignition temperature of coal as well as increases the maximal heat flow and its temperature. Application of the additive significantly decreases oxygen O2 concentration, while maintaining the same flue gas temperature. This affects the increase of efficiency of low power boiler by 2.49 p.p. (percentage point). Emission of hydrocarbons, formaldehyde, benzene and hydrogen cyanide was lowered, whereas there was no significant impact on SO2 and NOx emission. The studies carried on the industrial boiler with thermal output of 12 MW demonstrate that the flue gas heat loss and unburnt fuel heat loss decreased by ca. 2 p.p. As a result, the efficiency increased from ca. 86 to 88% which, in turn, influences the decrease of CO2 emission per unit of energy by 5%. The originality of the work is comprehensive research on the impact of additive on the coal combustion process, mainly concerning the efficiency.

ACS Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec; Maciej Dudek; Rafał Szleper. Improvement of coal boiler’s efficiency after application of liquid fuel additive. Applied Thermal Engineering 2020, 179, 115663 .

AMA Style

Robert Junga, Janusz Pospolita, Patrycja Niemiec, Maciej Dudek, Rafał Szleper. Improvement of coal boiler’s efficiency after application of liquid fuel additive. Applied Thermal Engineering. 2020; 179 ():115663.

Chicago/Turabian Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec; Maciej Dudek; Rafał Szleper. 2020. "Improvement of coal boiler’s efficiency after application of liquid fuel additive." Applied Thermal Engineering 179, no. : 115663.

Journal article
Published: 18 September 2019 in Renewable Energy
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The main goal of this paper is the evaluation of combustion and grindability of torrefied palm kernel shells (PKS) obtained in a pilot-scale installation. The torrefied samples were prepared in different time conditions and temperatures, ranged from 220 to 300 °C. The physico-chemical properties were identified. Thermogravimetric analyses (TG-DTA) were used for characterization of the combustion performance and evaluation of the activation energy Eα. The grindability of the pre-treated biofuel was investigated in a pilot-scale, coal bowl-roller milling unit. The results were compared to those of the raw PKS and bituminous coal. Torrefaction was found to increase carbon C content and HHV by 2–33 and 2–26%, respectively. Moreover, the combustion characteristics of the torrefied PKS samples are close to each other, but the ignition and burn-out temperatures differ significantly. The torrefaction changes the activation energy Eα and it approaches the Eα values to those of coal. Both the torrefaction temperature and residence time significantly affect the grindability. The grinding effect of PKS torrefied at 220 °C reached the value of 10%, whereas after torrefaction at 300 °C it doubled. The torrefaction considerably improves the properties and combustion behaviour of biomass, which is a good predictor for burning and co-burning in industrial units.

ACS Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec. Combustion and grindability characteristics of palm kernel shells torrefied in a pilot-scale installation. Renewable Energy 2019, 147, 1239 -1250.

AMA Style

Robert Junga, Janusz Pospolita, Patrycja Niemiec. Combustion and grindability characteristics of palm kernel shells torrefied in a pilot-scale installation. Renewable Energy. 2019; 147 ():1239-1250.

Chicago/Turabian Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec. 2019. "Combustion and grindability characteristics of palm kernel shells torrefied in a pilot-scale installation." Renewable Energy 147, no. : 1239-1250.

Journal article
Published: 01 April 2019 in Energies
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Animal waste, including chicken manure, is a category of biomass considered for application in the energy industry. Poland is leading poultry producer in Europe, with a chicken population assessed at over 176 million animals. This paper aims to determine the theoretical and technical energy potential of chicken manure in Poland. The volume of chicken manure was assessed as 4.49 million tons per year considering three particular poultry rearing systems. The physicochemical properties of examined manure specimens indicate considerable conformity with the data reported in the literature. The results of proximate and ultimate analyses confirm a considerable effect of the rearing system on the energy parameters of the manure. The heating value of the chicken manure was calculated for the high moisture material in the condition as received from the farms. The value of annual theoretical energy potential in Poland was found to be equal to around 40.38 PJ. Annual technical potential of chicken biomass determined for four different energy conversion paths occurred significantly smaller then theoretical and has the value from 9.01 PJ to 27.3 PJ. The bigger energy degradation was found for heat and electricity production via anaerobic digestion path, while fluidized bed combustion occurred the most efficient scenario.

ACS Style

Mariusz Tańczuk; Robert Junga; Alicja Kolasa-Więcek; Patrycja Niemiec. Assessment of the Energy Potential of Chicken Manure in Poland. Energies 2019, 12, 1244 .

AMA Style

Mariusz Tańczuk, Robert Junga, Alicja Kolasa-Więcek, Patrycja Niemiec. Assessment of the Energy Potential of Chicken Manure in Poland. Energies. 2019; 12 (7):1244.

Chicago/Turabian Style

Mariusz Tańczuk; Robert Junga; Alicja Kolasa-Więcek; Patrycja Niemiec. 2019. "Assessment of the Energy Potential of Chicken Manure in Poland." Energies 12, no. 7: 1244.

Journal article
Published: 21 December 2018 in Journal of the Energy Institute
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The purpose of the work is to determine the impact of a commercial coal additive on the efficiency and the pollutants emissions of an industrial boiler. The tests were carried out in a 41.1 MW thermal output moving grate boiler in common operating conditions for a period of two months. At that time, coal was alternately dosed with and without the additive. The amount of the additive to coal ratio was fixed at 1L/Mg during the tests. The additive applied was a 20% aqueous solution of four compounds, i.e. isopropanol, manganese (II) acetate tetrahydrate, acetic acid glacial … % and N,N-Dimethylethanolamine. The samples of coal, bottom and fly ash were collected from the installation twice a day during the tests in order to check their properties. The boiler's main energy parameters and the emission levels of CO, NOx, SO2 and dust were measured and registered. The additive influence on the boiler operation was evaluated based on the efficiency and three indicators which highlighted this impact. The additive influence was mainly demonstrated in boiler efficiency increase, in the range of 0.5–1 p.p., as well as the oxygen concentration in the flue gas which indicates that there was a decreased amount of the combustion air. On the other hand, the studies do not show any evident influence on the NOx, SO2 and CO emissions with the applied catalyst to fuel ratio. The research showed that even a little improvement of efficiency gives a measurable economic effect.

ACS Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec; Maciej Dudek. The assessment of the fuel additive impact on moving grate boiler efficiency. Journal of the Energy Institute 2018, 92, 1807 -1820.

AMA Style

Robert Junga, Janusz Pospolita, Patrycja Niemiec, Maciej Dudek. The assessment of the fuel additive impact on moving grate boiler efficiency. Journal of the Energy Institute. 2018; 92 (6):1807-1820.

Chicago/Turabian Style

Robert Junga; Janusz Pospolita; Patrycja Niemiec; Maciej Dudek. 2018. "The assessment of the fuel additive impact on moving grate boiler efficiency." Journal of the Energy Institute 92, no. 6: 1807-1820.

Journal article
Published: 30 March 2018 in Energies
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Coal continues to dominate in the structure of the heat production system in some European countries. Coal-fired boilers in district heating and power generation systems are accompanied by the formation of large quantities of slag and ash. Due to considerable high temperature, slag may be used as a source of waste energy. In this study, the technical possibilities of recovery slag’s physical enthalpy from grate-fired district heating boiler of 45 MW thermal capacity are analyzed. The aim of the work is to estimate the waste energy potential of the slag in analyzed boiler and proposition of the heat recovery system. The construction and design of the existing deslagging system was examined. Studies have shown that high water temperature accelerates system wear. Recovering heat from this system decreases the water temperature, which extends the trouble-free working time. The slag parameters were determined, including the temperature at the outlet of the boiler and the temperature after leaving the slag water tub. The annual amount of heat regenerative potential was estimated. On the basis of the research, the authors propose a waste heat recovery facility with high temperature R134a heat pump system. The result of the conducted research is that the proposed heat pump provides energy savings that are worth considering by recovering from 58.8% to 88.0% of energy slag potential.

ACS Style

Mariusz Tańczuk; Maciej Masiukiewicz; Stanisław Anweiler; Robert Junga. Technical Aspects and Energy Effects of Waste Heat Recovery from District Heating Boiler Slag. Energies 2018, 11, 796 .

AMA Style

Mariusz Tańczuk, Maciej Masiukiewicz, Stanisław Anweiler, Robert Junga. Technical Aspects and Energy Effects of Waste Heat Recovery from District Heating Boiler Slag. Energies. 2018; 11 (4):796.

Chicago/Turabian Style

Mariusz Tańczuk; Maciej Masiukiewicz; Stanisław Anweiler; Robert Junga. 2018. "Technical Aspects and Energy Effects of Waste Heat Recovery from District Heating Boiler Slag." Energies 11, no. 4: 796.

Conference paper
Published: 23 October 2017 in E3S Web of Conferences
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This paper treats about the impact fuels from biomass wastes and coal combustion on a small boiler operation and the emission of pollutants in this process. Tests were performed in laboratory conditions on a water boiler with retort furnace and the capacity of 10 kW. Fuels from sewage sludge and agriculture wastes (PBZ fuel) and a blend of coal with laying hens mature (CLHM) were taken into account. The results in emission changes of NOx, CO2, CO and SO2 and operating parameters of the tested boiler during combustion were investigated. The obtained results were compared with corresponding results of flame coal (GFC). Combustion of the PBZ fuel turned out to be a stable process in the tested boiler but the thermal output has decreased in about 30% compared to coal combustion, while CO and NOx emission has increased. Similar effect was observed when 15% of the poultry litter was added to the coal. In this case thermal output has also decreased (in about 20%) and increase of CO and NOx emission was observed. As a conclusion, it can be stated that more effective control system with an adaptive air regulation and a modified heat exchanger could be useful in order to achieve the nominal power of the tested boiler.

ACS Style

Robert Junga; Mirosława Kaszubska; Małgorzata Wzorek. Technical and environmental performance of 10 kW understocker boiler during combustion of biomass and conventional fuels. E3S Web of Conferences 2017, 19, 1009 .

AMA Style

Robert Junga, Mirosława Kaszubska, Małgorzata Wzorek. Technical and environmental performance of 10 kW understocker boiler during combustion of biomass and conventional fuels. E3S Web of Conferences. 2017; 19 ():1009.

Chicago/Turabian Style

Robert Junga; Mirosława Kaszubska; Małgorzata Wzorek. 2017. "Technical and environmental performance of 10 kW understocker boiler during combustion of biomass and conventional fuels." E3S Web of Conferences 19, no. : 1009.

Journal article
Published: 01 October 2017 in Renewable Energy
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ACS Style

Robert Junga; Waldemar Knauer; Patrycja Niemiec; Mariusz Tańczuk. Experimental tests of co-combustion of laying hens manure with coal by using thermogravimetric analysis. Renewable Energy 2017, 111, 245 -255.

AMA Style

Robert Junga, Waldemar Knauer, Patrycja Niemiec, Mariusz Tańczuk. Experimental tests of co-combustion of laying hens manure with coal by using thermogravimetric analysis. Renewable Energy. 2017; 111 ():245-255.

Chicago/Turabian Style

Robert Junga; Waldemar Knauer; Patrycja Niemiec; Mariusz Tańczuk. 2017. "Experimental tests of co-combustion of laying hens manure with coal by using thermogravimetric analysis." Renewable Energy 111, no. : 245-255.

Journal article
Published: 04 April 2009 in Powder Technology
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Graphical abstract Based on the measurements of the thickness of a bulk coal layer, several calculations were performed for the following parameters, i.e. average radial velocities for different rotary velocities of the table, feed stream, pile-up ring heights, and two different table–roller spacings. The results were then supplemented with test based on the movement of markers over the surface layer of the coal bulk. The test enabled the material's average radial and tangential velocities in the surface layer to be determined. A change in the table's rotary velocity results in an accumulation or release of a considerable part of the material. Thus, the rotary velocity may be a useful parameter in a mill control system.

ACS Style

Robert Junga; Stanisław Mateuszuk; Janusz Pospolita. Investigations into the movement of milled medium in the bowl of a ring-roller mill. Powder Technology 2009, 191, 61 -71.

AMA Style

Robert Junga, Stanisław Mateuszuk, Janusz Pospolita. Investigations into the movement of milled medium in the bowl of a ring-roller mill. Powder Technology. 2009; 191 (1):61-71.

Chicago/Turabian Style

Robert Junga; Stanisław Mateuszuk; Janusz Pospolita. 2009. "Investigations into the movement of milled medium in the bowl of a ring-roller mill." Powder Technology 191, no. 1: 61-71.