Paliva最新文献

{"title":"The Future of the Czech Gas Industry","authors":"K. Ciahotný","doi":"10.35933/paliva.2023.02.02","DOIUrl":"https://doi.org/10.35933/paliva.2023.02.02","url":null,"abstract":"In the Czech Republic, the gas industry is a key sector for ensuring the successful growth of industrial production and the growth of the standard of living. However, the set of Green Deal agreements recently adopted by the European Union envisages the gradual reduction of natural gas consumption and its replacement by ecologically produced (green) hydrogen. However, the production of green hydrogen in the Czech Republic is not yet industrially established, and its realisation will require considerable financial sums as investments in the relevant infrastructure. This will be reflected in a significant increase in the price of gas containing the prescribed proportion of green hydrogen. The planned addition of a certain proportion of hydrogen to natural gas will bring a number of complications to the gas industry. Production of a sufficient amount of green hydrogen, which should be added to natural gas, is not ensured in the Czech Republic or in the EU and will require considerable investment in the production infrastructure, which will in the final phase be transferred for the most part to the end consumer of the mixed gas. Total gas consumption will increase by 13%, as hydrogen has three times lower calorific value compared to methane, which is the majority component of natural gas. The reduction in greenhouse gas emissions will therefore be minimal or, taking into account the carbon footprint of the additional equipment needed for hydrogen production, even negative.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46191731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of rheological properties of crude oil blends","authors":"D. Maxa","doi":"10.35933/paliva.2023.01.05","DOIUrl":"https://doi.org/10.35933/paliva.2023.01.05","url":null,"abstract":"The article presents an overview of widely applicable methods of calculation of viscosity of liquid mixtures, as well as rheology characterisation of crude oil. It is focused on the evaluation of rheological properties, particularly in order to assess the flow conditions in pipelines at different temperatures and flow rates, especially in the case of waxy crude oils. A specific calculation procedure was proposed and described, suitable for practical purposes, i.e. field implementation in the form of a spreadsheet calculator. Using this method, it is possible to calculate the rheological properties of a mixture of known components at a given temperature over a range of shear gradients corresponding to a specified range of flow rates in a circular pipeline of specified diameter. The proposed calculation method was verified on the properties of specific types of oils and their mixtures.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43814432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Properties and Analysis of Liquid Alternative Fuels II: Alcohols and Ethers","authors":"Martin Staš, L. Matějovský, Z. Mužíková, J. Kroufek, P. Šimáček","doi":"10.35933/paliva.2023.01.01","DOIUrl":"https://doi.org/10.35933/paliva.2023.01.01","url":null,"abstract":"The importance of alternative fuels and their share in total energy consumption is constantly growing. The reason is, on the one hand, the saving of the gradually decreasing reserves of fossil fuels and also the effort to gradually reduce the emissions of carbon dioxide and other harmful substances. This article is another in a series of articles focused on an overview of the technical requirements and possibilities for testing alternative fuels. These articles aim to provide an overview of the required properties of individual alternative fuels, an overview of the prescribed analytical tests, and explain their relevance. This article focuses on liquid alternative fuels containing ethanol.\u0000Ethanol is currently the most widespread alternative oxygen fuel and, at the same time, also a biofuel. In pure form (E100), ethanol is used only exceptionally. Far more often, it is used as a bio-component of gasoline fuels.\u0000This article provides an overview of the technical requirements prescribed by legislation and relevant standards for ethanol for blending into gasoline fuels, and fuels containing ethanol. From ethanol-gasoline blends, E5, E10, and E85 are discussed. In addition, E95 fuel is discussed as well. The article also presents prescribed analytical tests for monitoring the quality of these fuels, or fuel components.\u0000Generally, in ethanol fuels or pure ethanol according to EN 15376, the composition is mostly analysed by GC. GC analysis determines the content of main and secondary oxygen components and/or the content of other impurities. In addition, the water content, total acidity, chloride and sulfate content, non-volatile impurities content, and the content of selected metallic and non-metallic elements, especially sulfur, are monitored in these matrices. For fuels intended for combustion in gasoline engines (E5, E10, and E85), important monitored parameters are also vapor pressure, oxidation stability, as well as density and corrosion on copper.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41796092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen production using nuclear power plants","authors":"J. Ballek, T. Hlinčík","doi":"10.35933/paliva.2023.01.02","DOIUrl":"https://doi.org/10.35933/paliva.2023.01.02","url":null,"abstract":"In the coming years, the global demand for hydrogen can be expected to grow gradually, with increasing pressure to produce without the use of natural gas or oil. As a result, possible ways to produce hydrogen that will have a lower carbon footprint are being sought. Apart from the use of renewable energy sources, nuclear energy appears to be another possible source. This article provides an overview of available and suitable technologies that use nuclear energy. These include in particular water electrolysis, thermochemical decomposition of water or hybrid cycles. The article also includes an overview of individual research programs in the world.\u0000A nuclear power plant, in conjunction with hydrogen production, could serve as a backup flexible energy source in addition to coal and gas power plants to stabilize fluctuations in the electrical transmission system due to the operation of renewable energy sources.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47626928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-temperature treatment of waste crosslinked polyethylene with ruthenium catalyst","authors":"P. Straka, O. Bičáková, J. Cihlař","doi":"10.35933/paliva.2023.01.03","DOIUrl":"https://doi.org/10.35933/paliva.2023.01.03","url":null,"abstract":"A method of processing of waste cross-linked polyethylene (PEX) by low-temperature pyrolysis with a Ru/Al2O3 catalyst was developed. The catalyst used, even in a small amount, significantly supported the splitting of the PEX structure, so that the yield of the key product, oil, reached 90%. Further, an energy gas with a HHV of 48.5 MJ/kg was obtained, suitable for further use. The minority products were paraffin and a solid carbonaceous residue. A mass and energy balances of the process and their comparison with those without a catalyst were carried out. In the case of catalyzed pyrolysis, it was found that 96.5% of the energy content of the starting raw material was preserved in the products with a high utility value. More in details, the ruthenium catalyst favorably affected the low-temperature pyrolysis of waste PEX, as the amount of main product, oil, obtained with the catalyst was clearly higher (90%) compared to the amount of oil obtained without one (85%). The composition of the pyrolysis gas was also favorably influenced by the ruthenium catalyst as the gaseous hydrocarbon contents were significantly higher compared to those of uncatalyzed pyrolysis. A small amount of Ru was needed for such effects, since the Ru/PEX ratio was 0.75/100 (g/g). This fact compensates, or at least partially, the relatively high price of this catalyst compared to, for example, nickel-based or FCC catalysts. Minority products, paraffin and solid carbon residue are well usable in practice. Paraffin is a necessary substance in a number of industries (medicine, cosmetics, wood impregnation, construction, candle production, skiing wax production); the solid carbonaceous residue can be used as clean sulfur-free and low-ash fuel.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44099595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flue gas condensation of solid fuel fired heating plant","authors":"Ondřej Haváček, Alice Vagenknechtová","doi":"10.35933/paliva.2023.01.04","DOIUrl":"https://doi.org/10.35933/paliva.2023.01.04","url":null,"abstract":"In the Czech Republic, increasing trend exists in utilization of biomass as a fuel in heating and power plants. This is preferred solution by EU Climate plans, and it is connected with some economic benefits (e.g. green bonuses, guaranteed purchase price), on the other hand the combustion of fossil fuels is penalized (EU ETS – Emission Trading System). There are many types of biomass with different parameters but one of the most discussed are wooden resides because of its quantity.\u0000There are big differences between quality parameters, especially in moisture content, which is decreasing the LHV. There are some technologies which can decrease moisture. Dryer technologies could be simple so-lution, but final decreasing of moisture is quite low. More effective is application of flue gas condensation. This technology is well known for gas-fired boilers but nowa-days is still more often build by new solid fuels-fired plants.\u0000This deals with design of condensation technology for existing heating plant in Mladá Boleslav. The fuel mixture is based on wood residues (70 %) and pelletized plant biomass (30 %). The calculation was done for three boilers for soild fuels – two same CFBs (steam production 100 t·h-1) and one BFB (steam production 80 t·h-1). Moisture content was calculated for two cases of wooden residues with moisture content 35 and 50 %. System of condensation include three step water scrubber, heat ex-changer, heat pump and humidifier of combustion air.\u0000The final designed output of unit for BFB is 12.7 MW (19 MW for each CFBs), but from these the output of heat pump is 5 MW (7.5 MW). The source of heat for heating pumps is steam, which can be used in current heater, so the final net output from condensation is 7.7 MW (11.5 MW). These parameters are only for 50 % of moisture content in wooden residues.\u0000The application of these system is not cost-effective for moisture content of fuel around 35 %. It is possible to build this technology for 50 % of fuel moisture content, but technology will not raise the temperature parameters of hot water. There are two differences between Mladá Boleslav heating plant and Finnish Vuosaari power plant in Helsinky, where the similar unit is already built. First of them is moisture content of fuel more than 50 %. Second one is temperature of hot water system 60 °C, however in Mladá Boleslav is at least 80 °C, sometimes it could be more than 110 °C. The decreasing of this temperature is problem because the most of heating systems were designed by current standards with temperature 80 °C.\u0000The only possible solution is to build two steps scrubber and the waste heat utilize as preheater of hot water.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46404704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of sulfur dioxide on adsorption capacity of zeolite sorbents for carbon dioxide","authors":"M. Staf","doi":"10.35933/paliva.2022.04.01","DOIUrl":"https://doi.org/10.35933/paliva.2022.04.01","url":null,"abstract":"The article discusses a rather serious problem limit-ing the use of adsorption for the CO2 capture from flue gas, in the presence of sulfur dioxide. An apparatus with a vertical batch adsorber was constructed to study adsorption under elevated pressure in a wide range of temperatures and evaluation of CO2 breakthrough curves with an infrared analyzer. The article summarizes the results of experiments conducted with zeolite clinoptilolite, which represented natural materials, and molecular sieve 13X as a representative of synthetic sorbents. Adsorption capacities achieved during cyclically repeated tests with a model gaseous mixture free of SO2 and a mixture of the same composition but enriched with a low volume fraction of SO2 (0.3 %) were compared.\u0000Adsorption took place at a temperature of 20 °C and at two overpressures (200 and 500 kPa) of the gas with a 13 % volume fraction of CO2. Each sub-experiment consisted of five adsorption and desorption cycles, where desorption was based on depressurization followed by temperature increase to 120 °C under nitrogen atmosphere. There were no changes in capacities when tested with the gaseous mixture without SO2. Relative to the weight of the sample, the 13X sample at an overpressure of 500 kPa had a capacity of 11.3 % and clinoptilolite 3.8 %. Tests in the presence of SO2 led to a permanent reduction of the equilibrium capacities for both samples and at both pressures. At the overpressure of 500 kPa, the capacity decreased to 7.4 % for the 13X and to 2.5 % for the clinoptilolite. A more intensive desorption involving a thermal and vacuum step did not lead to any improvement for the 13X sample. In contrast, the effect for clinoptilolite was very positive. Its capacity in the fifth cycle reached 3.4 % close to the state without SO2 exposition.\u0000In the case when SO2 in the gas was accompanied with 40 % relative humidity, vacuum desorption did not lead to positive results in any case. After five cycles, the capacity of 13X dropped to 3.2 % and clinoptilolite to 1.4 %. When moisture, SO2 and the presence of O2 (volume fraction of 6 %) in the model mixture were further combined, the capacity of 13X decreased to 1.4 % and clinoptilolite to 0.4 % after five cycles.\u0000Tests with SO2 (dry gas) caused a decrease in the specific surface area from 512 to 211 m2.g‒1 for the 13X sample. On the other hand, for clinoptilolite it decreased from only 29 to 28 m2.g‒1 under the same conditions. Ac-cording to XRF, it was not possible to remove sorbed SO2 from the 13X sample even by evacuation followed by heating up to 200 °C. Using the XRD method, it was found that SO2 remains in the matrix, although it does not undergo transition to the crystalline phase. The study verified that synthetic molecular sieve 13X, unlike natural clinoptilolite, is not applicable for CO2 adsorption from SO2 containing flue gas.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48554087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operational concerns from compliance of IMO2020 sulphur limit through VLSFO","authors":"Abhay Singh, S. Shanthakumar","doi":"10.35933/paliva.2022.04.02","DOIUrl":"https://doi.org/10.35933/paliva.2022.04.02","url":null,"abstract":"From Jan 01, 2020, International Maritime Organisation (IMO) reduced the permissible sulphur content from bunker fuel used on ships from 3.5 % m/m in 2012 to 0.50 % m/m. The maritime industry is consequently abandoning High Sulphur Fuel Oil (HSFO) and employing Very Low Sulphur Fuel Oil (VLSFO) blends or using the Exhaust Gas Cleaning System (EGCS) that allows the combustion of HSFO by removing access sulphur from the exhaust gas of a ship. However, these compliance mechanisms present their own Technical and operational challenges. The concern that the specifications of VLSFO are hidden is groundless, as they must comply with ISO 8217. Thus, the problems with VLSFO blends are not their specs but the difficulty attached to their handling and use. Major problems with VLSFO blends are the breakdown of the main engine, poor liner conditions, collapsed piston rings, and consequential scuffing caused by mismanagement of cylinder oil and feed rate, improper maintenance of Piston Rings and Cylinder liner. Some other concerns with VLSFO blends are low shelf life, high sensitivity, admissibility of onboard testing, the readiness of seafarers, and other compliance difficulties. Training seafarers, technological awareness, and constant care can only achieve adequate compliance.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47130191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas production in the Czech Republic yesterday, today and tomorrow","authors":"K. Ciahotný, Josef Kahlen","doi":"10.35933/paliva.2022.04.03","DOIUrl":"https://doi.org/10.35933/paliva.2022.04.03","url":null,"abstract":"The Czech Republic is one of the most advanced countries in the world in the field of gas industry. The production of gas from coal started here as early as 1847 and has been developing intensively since then. Initially, the gas was used to light the streets, which is why it was referred to as town gas. Soon its use also spread to other areas, e.g. for heating water and housing heating, but also for washing clothes and almonds and a number of other activities. A significant change occurred in the middle of the 20th century, when the process of coal gasification was developed, which began to replace the less effective methods of gas production with carbonization. The first pressurized gas plant in Bohemia was put into operation during the 2nd world war in Záluží near Litvínov and supplied gas not only to local chemical plants, but also to large cities in its vicinity via a high-pressure gas pipeline. Other pressurized gas plants were located in the 1950s in Úžín and in the early 1970s in Vřesová. The production of town gas in the Czech Republic at that time reached a volume of almost 4 billion m3/a. The construction of the transit gas system from the Soviet Union to mainland Central and Western Europe and its commissioning in the first half of the 1970s meant a gradual decline in the production of town gas and its replacement by natural gas. Therefore, the pressurized gas plants were gradually taken out of operation. The last gas plant in Vřesová ceased operation in the summer of 2020. However, gas production technologies are still being developed in the Czech Republic. Several devices for gasification of bio-mass and devices intended for gasification of various al-ternative fuels have been implemented. The interruption of natural gas supplies from Russia in the summer of 2022 has again revived interest in these technologies, especially in industrial enterprises with high gas consumption in technological processes.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46194005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrosion of structural materials for salt melt technologies","authors":"Jana Rejková, Marie Kudrnová","doi":"10.35933/paliva.2022.04.04","DOIUrl":"https://doi.org/10.35933/paliva.2022.04.04","url":null,"abstract":"Molten salt mixtures are considered media for many modern technologies using their ability to store thermal energy, thermal stability at high temperatures, low melting point, and other properties. The disadvantage of their use is high corrosion aggressiveness towards metal structural materials. In particular, impurities contained in salt mixtures can significantly increase the corrosion rates of alloys. This paper compares the corrosion behaviour of Inconel 625, 321, 316L and 316Ti alloys in a mixture of chloride and nitrate salt melts. The parameters in which both mixtures are stable and in melt form were chosen -400 °C, an inert argon atmosphere, and a pressure of 0.2 MPa. After exposure, the state and composition of the surfaces were analysed by XPS (X-ray photoelectron spectroscopy) and SEM (Scanning Electron Microscopy). These materials are better suitable for nitrate salt environments, where only very thin surface layers were formed without local types of corrosion. In chloride melts, Alloy 321 and Inconel 625 have shown greater resistance than 316L and 316Ti stainless steels.","PeriodicalId":36809,"journal":{"name":"Paliva","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42768855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}