The currently applied methodology of absolute gassiness forecasting in roadways being driven in Polish hard coal mines is based on the results of investigations frombefore more than twenty years. At present the roadwa...The currently applied methodology of absolute gassiness forecasting in roadways being driven in Polish hard coal mines is based on the results of investigations frombefore more than twenty years. At present the roadways are being driven in majority ofcases in quite different conditions than those which had been the subject of the said investigations. The application of 'old' methods of forecasting of methane emission during driving of roadways often brings about great discrepancies between the results of the forecasts and actual situation. It is firstly necessary to determine a potential set of factorswhich exert an influence on situation regarding methane emission into roadways beingdriven in order to prepare a verified mathematical model of absolute gassiness forecastingOn the basis of available literature and the investigations conducted by the Central MiningInstitute an initial list of factors has been prepared which can have an impact upon methane emission into roadways being driven. The assumptions of heuristic method have beentaken advantage of for selection of parameters and indices describing the phenomenon ofmethane emission. It has been dictated by the fact that the available literature is lacking apretty unambiguous viewpoint on the subject under consideration and at the same time itis necessary to perform an a priori assessment of the information contained in a givenfeature (factor). A prepared initial set has been scrutinized to be verified on the basis of aconducted expert survey among seventy specialists in this field. After collecting of the results of the survey their statistical elaboration was prepared. The co-efficient of agreementof multiple ordering, the so called concordance co-efficient has been taken advantage of inorder to check the competency of experts. The investigations prove that the experts are inagreement in their opinions. The estimation of a collective assessment of all participants ofthe survey was conducted with the use of the rank sum's test by J. Gren, The results ofthe conducted analysis allowed determining a potential set of factors which influence thesituation of methane emission into roadways being driven. This set, after conductance offurther detailed investigations, can constitute a base for elaboration of a function describ-ing methane emission into roadways being driven in hard coal mines.展开更多
The paper presents the results of a two-year research of properties and the way of use of briquettes and pellets made of separated and partially dehydrated digestate from agricultural BGSs （biogas stations）. Digesta...The paper presents the results of a two-year research of properties and the way of use of briquettes and pellets made of separated and partially dehydrated digestate from agricultural BGSs （biogas stations）. Digestate is a by-product of BGS. There are approximately 170 agricultural BGSs operating in the Czech Republic. Unprocessed digestate with the dry mass content around 6% is usually applied to soil as a lighter mineral fertilizer. If digestate is separated and the separated solid component of the digestate is further dehydrated to 14 % moisture, it can be processed by pressing to the form of very solid pellets and briquettes, also with various additives. It was also ascertained that mechanical strength and shape of briquettes does not change due to long-term storage. In this form, the compressed digestate can be used in various ways. One of the ways is its energetic use by direct burning. That is why we have observed its calorific value and combustion heat. Another alternative use of compressed digestate from BGS is its application in targeted treatment of in particular mechanical properties of soil and its water regime. The briquettes and pellets have great water sorption properties--the briquette retains water and as a consequence grows up to four times in size. This specific property was analysed and it was ascertained that the speed of water sorption depends on the composition of the compressed mixture （i.e., the type of material and the size of its particles）, but also on the total weight of the produced briquettes （i.e., their size）. Similar dependency was ascertained for other briquette materials that were analysed.展开更多
Latin American and the Caribbean countries have one of the world＇s largest sources of renewable energy. Nonetheless, it estimated that nearly three-quarters of their energy consumption relies on the use of fossil fue...Latin American and the Caribbean countries have one of the world＇s largest sources of renewable energy. Nonetheless, it estimated that nearly three-quarters of their energy consumption relies on the use of fossil fuels, with most of the countries being net importers, ultimately imposing a marked economic and political dependence on those energy commodities. Therefore, the opportunity lies in a higher utilization of various renewable energy resources, which contribute to the country＇s energy security while promoting significant environmental benefits. This manuscript aimed to provide a comparative analysis of current energy scenarios of six Latin American countries （Mexico, Honduras, Nicaragua, Brazil, Chile and Ecuador） to evaluate their policies, programs and strategies implemented in the search for greater participation of renewable energy, with a special attention to biogas. Given the importance of the water-energy-food nexus that could foment the use of renewable energies under conditions of water scarcity, a qualitative data comparison was accomplished, considering biogas production potential, biogas projects and CO2 emissions.展开更多
文摘The currently applied methodology of absolute gassiness forecasting in roadways being driven in Polish hard coal mines is based on the results of investigations frombefore more than twenty years. At present the roadways are being driven in majority ofcases in quite different conditions than those which had been the subject of the said investigations. The application of 'old' methods of forecasting of methane emission during driving of roadways often brings about great discrepancies between the results of the forecasts and actual situation. It is firstly necessary to determine a potential set of factorswhich exert an influence on situation regarding methane emission into roadways beingdriven in order to prepare a verified mathematical model of absolute gassiness forecastingOn the basis of available literature and the investigations conducted by the Central MiningInstitute an initial list of factors has been prepared which can have an impact upon methane emission into roadways being driven. The assumptions of heuristic method have beentaken advantage of for selection of parameters and indices describing the phenomenon ofmethane emission. It has been dictated by the fact that the available literature is lacking apretty unambiguous viewpoint on the subject under consideration and at the same time itis necessary to perform an a priori assessment of the information contained in a givenfeature (factor). A prepared initial set has been scrutinized to be verified on the basis of aconducted expert survey among seventy specialists in this field. After collecting of the results of the survey their statistical elaboration was prepared. The co-efficient of agreementof multiple ordering, the so called concordance co-efficient has been taken advantage of inorder to check the competency of experts. The investigations prove that the experts are inagreement in their opinions. The estimation of a collective assessment of all participants ofthe survey was conducted with the use of the rank sum's test by J. Gren, The results ofthe conducted analysis allowed determining a potential set of factors which influence thesituation of methane emission into roadways being driven. This set, after conductance offurther detailed investigations, can constitute a base for elaboration of a function describ-ing methane emission into roadways being driven in hard coal mines.
文摘The paper presents the results of a two-year research of properties and the way of use of briquettes and pellets made of separated and partially dehydrated digestate from agricultural BGSs （biogas stations）. Digestate is a by-product of BGS. There are approximately 170 agricultural BGSs operating in the Czech Republic. Unprocessed digestate with the dry mass content around 6% is usually applied to soil as a lighter mineral fertilizer. If digestate is separated and the separated solid component of the digestate is further dehydrated to 14 % moisture, it can be processed by pressing to the form of very solid pellets and briquettes, also with various additives. It was also ascertained that mechanical strength and shape of briquettes does not change due to long-term storage. In this form, the compressed digestate can be used in various ways. One of the ways is its energetic use by direct burning. That is why we have observed its calorific value and combustion heat. Another alternative use of compressed digestate from BGS is its application in targeted treatment of in particular mechanical properties of soil and its water regime. The briquettes and pellets have great water sorption properties--the briquette retains water and as a consequence grows up to four times in size. This specific property was analysed and it was ascertained that the speed of water sorption depends on the composition of the compressed mixture （i.e., the type of material and the size of its particles）, but also on the total weight of the produced briquettes （i.e., their size）. Similar dependency was ascertained for other briquette materials that were analysed.
文摘Latin American and the Caribbean countries have one of the world＇s largest sources of renewable energy. Nonetheless, it estimated that nearly three-quarters of their energy consumption relies on the use of fossil fuels, with most of the countries being net importers, ultimately imposing a marked economic and political dependence on those energy commodities. Therefore, the opportunity lies in a higher utilization of various renewable energy resources, which contribute to the country＇s energy security while promoting significant environmental benefits. This manuscript aimed to provide a comparative analysis of current energy scenarios of six Latin American countries （Mexico, Honduras, Nicaragua, Brazil, Chile and Ecuador） to evaluate their policies, programs and strategies implemented in the search for greater participation of renewable energy, with a special attention to biogas. Given the importance of the water-energy-food nexus that could foment the use of renewable energies under conditions of water scarcity, a qualitative data comparison was accomplished, considering biogas production potential, biogas projects and CO2 emissions.
