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This paper examines the influence of pressure on the crystalline properties of CaCO3 precipitate from drinking water and model aqueous solutions. Seven different evaporation models were examined. Evaporation was performed with a rotary evaporator, pressure vessel, and evaporation at atmospheric pressure at 373 K. Evaporation was also performed with a pressure vessel using a model aqueous solution in the presence of Mg2+ ions, which are CaCO3 inhibitors. Measurements of absorbency, turbidity, pH value, zeta potential and particle size were performed at different time units after the precipitation of CaCO3 from a model aqueous solution and tap water. The precipitated crystals were determined by XRD and SEM. It can be concluded that pressure affects the properties of CaCO3, but not immediately after CaCO3 precipitation. The changes began after 15 min of model sample processing. Calcite was precipitated in all experiments, except in one with Mg2+ ions when aragonite was found. The treatment of tap water in a pressure vessel favoured aragonite precipitation, although later the aragonite modified into calcite.
Marjana Simonič; Darko Goričanec; Danijela Urbancl. Influence of pressure and Mg2+ ions on crystalline properties of calcium carbonate. Journal of Molecular Liquids 2021, 334, 116462 .
AMA StyleMarjana Simonič, Darko Goričanec, Danijela Urbancl. Influence of pressure and Mg2+ ions on crystalline properties of calcium carbonate. Journal of Molecular Liquids. 2021; 334 ():116462.
Chicago/Turabian StyleMarjana Simonič; Darko Goričanec; Danijela Urbancl. 2021. "Influence of pressure and Mg2+ ions on crystalline properties of calcium carbonate." Journal of Molecular Liquids 334, no. : 116462.
The article presents an original and innovative technical solution for the exploitation of low-temperature excess heat from hot water boilers that use gas or liquid fuel for the needs of high-temperature heating in buildings or in industry. The primary fuel efficiency used for hot water boilers can be significantly increased by utilizing the excess low-temperature heat of flue gases that are discharged into the environment and thus also reduce CO2 emissions. Hot water systems usually operate at higher temperatures of the heating water, which is transported to the heat consumer via supply pipe, and the cooled heating water is returned to the hot water boiler via the return pipe. For the excess low-temperature heat exploitation of the flue gases from hot water boiler, it is necessary to install a condenser in the flue gas discharge pipe, where condensation of water vapour present in the flue gas heats water or a mixture of water and glycol. The heating water, which is cooled and returned from the heat consumer via the return pipe, is led to the condenser of the high-temperature heat pump, where it is preheated and then led to the hot water boiler, where it is heated to the final temperature. A computer simulation with the Aspen plus software package for the series or parallel connection of high-temperature heat pump to a hot water heating system and the economic analysis of the excess heat exploitation from the flue gases are also performed.
Darko Goričanec; Igor Ivanovski; Jurij Krope; Danijela Urbancl. The Exploitation of Low-Temperature Hot Water Boiler Sources with High-Temperature Heat Pump Integration. Energies 2020, 13, 6311 .
AMA StyleDarko Goričanec, Igor Ivanovski, Jurij Krope, Danijela Urbancl. The Exploitation of Low-Temperature Hot Water Boiler Sources with High-Temperature Heat Pump Integration. Energies. 2020; 13 (23):6311.
Chicago/Turabian StyleDarko Goričanec; Igor Ivanovski; Jurij Krope; Danijela Urbancl. 2020. "The Exploitation of Low-Temperature Hot Water Boiler Sources with High-Temperature Heat Pump Integration." Energies 13, no. 23: 6311.
Waste gases that cannot be released into the environment are generated in chemical industrial processes. There are various physico-chemical processes for the treatment of these gases, but in most cases, they present a major cost to the company. There is an EU directive for each industrial area describing the best available techniques (BAT) and the prescribed environmental limits for the maximum discharge of dangerous substances into the environment. The current process for the removal of formaldehyde and volatile organic compounds from waste industrial gases meets EU environmental regulations. However, expected new EU directives will require a significant reduction in formaldehyde and volatile organic compounds’ concentrations in industrial exhaust gases, thus necessitating a new technical solution for the removal of formaldehyde. This paper describes two methods of removing formaldehyde and volatile organic compounds from waste gases, generated by the metal oxide catalyst formaldehyde production processes. The first method involves upgrading existing processes of removing formaldehyde from waste gases with an additional absorption plant, with which emissions can be significantly reduced. The second method describes the co-incineration of waste gases generated by a metal oxide catalyst formaldehyde production process with natural gas in a gas turbine, where formaldehyde and volatile organic compounds are completely removed, while electricity is also produced. The second method is also useful for removing various concentrations of volatile organic compounds from waste gases generated in chemical industrial processes.
Jozsef Mursics; Danijela Urbancl; Darko Goricanec. Process of Formaldehyde and Volatile Organic Compounds’ Removal fromWaste Gases. Applied Sciences 2020, 10, 4702 .
AMA StyleJozsef Mursics, Danijela Urbancl, Darko Goricanec. Process of Formaldehyde and Volatile Organic Compounds’ Removal fromWaste Gases. Applied Sciences. 2020; 10 (14):4702.
Chicago/Turabian StyleJozsef Mursics; Danijela Urbancl; Darko Goricanec. 2020. "Process of Formaldehyde and Volatile Organic Compounds’ Removal fromWaste Gases." Applied Sciences 10, no. 14: 4702.
Torrefaction is an effective way to upgrade biomass for producing fuels. The experimental results of torrefaction for three materials, oak wood, mixed wood mainly from deciduous trees and sewage sludge are presented. The comparison between three materials is performed to evaluate the influence of temperature and time on torrefaction operation. The influence of the operating temperature and time was analysed in order to determine optimal operation parameters for the newly developed process which has been patented. Properties, such as heating value, mass loss, chemical compositions, energy yield and enhancement factor were investigated. The results show that from an energy point of view the optimal operation time for oak and mixed wood is around 1.2 h at 260 °C. The torrefaction of sewage sludge is energetically unjustified. The highest carbon loss is shown for mixed wood, following by sewage sludge and oak wood. Torrefaction severity index was established based on the, most severe conditions. Torrefaction severity index could be applied as an indicator for prediction of torrefaction efficiency of chosen material.
M. Simonic; D. Goricanec; D. Urbancl. Impact of torrefaction on biomass properties depending on temperature and operation time. Science of The Total Environment 2020, 740, 140086 .
AMA StyleM. Simonic, D. Goricanec, D. Urbancl. Impact of torrefaction on biomass properties depending on temperature and operation time. Science of The Total Environment. 2020; 740 ():140086.
Chicago/Turabian StyleM. Simonic; D. Goricanec; D. Urbancl. 2020. "Impact of torrefaction on biomass properties depending on temperature and operation time." Science of The Total Environment 740, no. : 140086.