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摘要:The overdependence on crude oil in African countries warrants the need for alternative sources of energy. A 56-litre-capacity biogas digester was designed, fabricated and evaluated. Investigations were made into the production of biogas from the mixture of cow dung, swine dung and poultry dropping. Standard equations and models were used in the design of the components of the manually operated digester. The digester temperature, ambient temperature and pH were monitored during the experiment. The proximate analysis showed that volatile solid, total solid and moisture content for the mixed substrates at the initial stage were: 64.7%, 83.5% and 13.5% respectively. Similarly, at the digestion stage, the volatile solid, total solid and moisture content were: 54.1%, 22.6% and 74.4% respectively. Advancement of decomposition leads to gradual increasing pH value from 7.2 to 7.4, which indicates the stability of organic matter. The moisture content on a wet basis was initially 13.5%. This value latter increased to 74.4%. On the average, 15 kg of mixed substrates with 25 litres of impure water produced biogas within 25 days of digestion. The gas produced from mixed substrates became flammable with blue flame after 16 days of production, indicating that the ratio of methane gas generated with the three mixtures of fresh animal waste was higher than other gases produced....
摘要:Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation and evolution history. The content of rare earth elements in stone coal has been the focus of attention. Stone coal is widely distributed in southern Shaanxi province of China. In order to study the content and distribution of rare earth elements in stone coal, and provide a plan for the comprehensive development and utilization of stone coal, this study tested the rare earth elements content of stone coal, parting and coal ash samples, respectively, compared the content of rare earth elements in stone coal, parting, coal ash with the mean value of China coal, the mean value of world coal and the abundance value of upper crust, and discussed the features of rare earth elements content in different types of samples in southern Shaanxi province of China. The average contents of rare earth elements in the samples of stone coal, parting and coal ash were calculated, and the enrichment coefficients of the samples with the mean value of China coal, the mean value of world coal and the abundance value of upper crust were listed. The distribution rules and characteristics of the contents of rare earth elements in different types of samples in southern Shaanxi province of China were summarized....
摘要:Coal during its carbonization process produces a gas. This gas, mainly formed by methane, can be used. This gas, coalbed methane (CBM), is usually mainly formed by methane and can be considered similar to natural gas as energy source. The evaluation of the techno-economic feasibility of the extraction of this gas depends on a large number of complex different factors. The work carried out covers the different aspects to simplify the first approach for CBM feasibility quantification considering a short number of indicators. A theoretical review and a state of the art description have been carried out, taking into account all the factors that can influence in the development of a CBM project. After that, technical feasibility has been used to evaluate total amount of gas that can be recovered. The last step was to evaluate economic feasibility to know how much gas could be economically profitable. Conclusions got have been used to develop a simple method for evaluating CBM economic feasibility considering just four easy known parameters of coal beds. These are: the rank, the thickness, the gas concentration, and the permeability....
摘要:The Design of Experiments (DOE) and the Analysis of Variance (ANOVA) are used to determine the effect of fuel type, fuel initial load, secondary air inlet and ventilation on thermal efficiency and CO emission of two biomass fire cookstoves during boiling or simmering. Analysis of variance with Fischer’s statistical test (F-test) and Newman-Keuls test were applied to establish the influence of the independent parameters on the studied responses. The results of this study are useful to application of charcoal cooks stoves....
摘要:Peat and peatified wood are significant carbohydrate resources in tropical rainforests. The carbohydrates of cellulose and hemicellulose are important sources of monosaccharides for both vital activities and industrial applications, such as furan production of furfural and hydroxymethyl furfural. Hydrothermal treatment at 200°C and ultrasonic irradiation pretreatment were used to recover monosaccharides from the abovementioned resources. The monosaccharide recovery from peat was shown to be higher than that from peatified wood. The conversion to organic acids is considered to proceed rapidly because acids are always detected with monosaccharides. This conversion is outstripped by the organic acid-to-gas reaction for treatment times longer than 20 min. The monosaccharide recovery from peatified wood was improved by the ultrasonication pretreatment. It is considered that ultrasonic irradiation broke down lignin blockages, enabling water molecules to access the carbohydrates more easily in the subsequent hydrothermal treatment....
摘要:Asphaltenes are complex molecular entities, which together with resins, aromatic hydrocarbons and saturates forms the crude oil. Asphaltenes and resins are in the thermodynamic equilibrium at static reservoir condition. However, asphaltene can precipitate due to changes in thermodynamic condition. Asphaltene deposition in production tubings has been an outstanding problem with wide economic impact on the oil industry. Meanwhile, the use of real-time tools to monitor depositions along the well is of great difficulty. In this work, the asphaltene precipitation region in a single phase flow wellbore is predicted for an oil well of the Iranian oil field. Then, asphaltene deposition thickness along the well is predicted for three time intervals. The simulation results indicated that asphaltene thickness exceeded more than 50% of tubing radius; therefore, a reduction in flow rate, an increase in pressure drop and tubing blockage are expected. Moreover, it is shown the deposits thickness along the wellbore has approximately a skew normal distribution shape, which could be the result of increases in velocity and excess pressure drop....
摘要:Coal mining has proven negative impacts on the landscape and health of inhabitants. Solid dust particles and SO2, which are the main polluting substances in coal mining and burning, are the main causes of diseases in areas with intensive coal mining. This contribution deals with areas in the Czech Republic which have the greatest problems in this regard, being North Bohemia (Chomutov, Most, Teplice and ústí nad Labem districts). It is an area with considerable anthropogenic activity, mainly due to the intensive mining of brown coal, which has a direct effect on the health of the inhabitants of the entire ústí nad Labem region. Along with the growing number of inhabitants, energy consumption demands are constantly increasing. Nevertheless, it’s important to focus primarily on renewable energy sources, which will ensure the sustainable development of the environment and society. At the same time, the question arises, which energy sources can potentially be utilized here after mining ends (2052). In terms of geography, wind energy has the greatest potential in this area. This and associated issues are dealt with by the project “Sustainable Forms of Management in an Anthropogenically Burdened Region” at the Faculty of Environment at the University of Jan E. Purkyně in ústí nad Labem....
摘要:Asphaltenes are complex molecular entities, which together with resins, aromatic hydrocarbons and saturates forms the crude oil. Asphaltenes and resins are in the thermodynamic equilibrium at static reservoir condition. However, asphaltene can precipitate due to changes in thermodynamic condition. Asphaltene deposition in production tubings has been an outstanding problem with wide economic impact on the oil industry. Meanwhile, the use of real-time tools to monitor depositions along the well is of great difficulty. In this work, the asphaltene precipitation region in a single phase flow wellbore is predicted for an oil well of the Iranian oil field. Then, asphaltene deposition thickness along the well is predicted for three time intervals. The simulation results indicated that asphaltene thickness exceeded more than 50% of tubing radius; therefore, a reduction in flow rate, an increase in pressure drop and tubing blockage are expected. Moreover, it is shown the deposits thickness along the wellbore has approximately a skew normal distribution shape, which could be the result of increases in velocity and excess pressure drop....
摘要:Coal mining has proven negative impacts on the landscape and health of inhabitants. Solid dust particles and SO2, which are the main polluting substances in coal mining and burning, are the main causes of diseases in areas with intensive coal mining. This contribution deals with areas in the Czech Republic which have the greatest problems in this regard, being North Bohemia (Chomutov, Most, Teplice and ústí nad Labem districts). It is an area with considerable anthropogenic activity, mainly due to the intensive mining of brown coal, which has a direct effect on the health of the inhabitants of the entire ústí nad Labem region. Along with the growing number of inhabitants, energy consumption demands are constantly increasing. Nevertheless, it's important to focus primarily on renewable energy sources, which will ensure the sustainable development of the environment and society. At the same time, the question arises, which energy sources can potentially be utilized here after mining ends (2052). In terms of geography, wind energy has the greatest potential in this area. This and associated issues are dealt with by the project “Sustainable Forms of Management in an Anthropogenically Burdened Region” at the Faculty of Environment at the University of Jan E. Purkyně in ústí nad Labem....
摘要:The current study investigated the effects of novel hybrid polyacrylamide polymers as ash (slime) depressants in fine coal flotation to enhance combustible recovery and ash rejection. Coal samples at P80 of approximately 45 um with ~25% ash content were floated in the presence of in-house synthesized hybrid aluminum hydroxide polyacrylamide polymers (Al(OH)3-PAM, or Al-PAM). All flotation experiments were carried out in a 5-L Denver flotation cell. Various influencing factors were examined to optimize the flotation process in the presence of the Al-PAM polymers, including the Al-PAM dosage, Al-PAM conditioning time, impeller rotation speed and pulp pH. Comparative and synergistic studies were also performed using organic polyacrylamide polymers (PAMs), commercial dispersants and Al-PAM/dispersant system. Results showed a significant improvement in both combustible recovery and ash rejection at an Al-PAM dosage of 0.25 mg/L. The maximum combustible recovery obtained, at natural pH, with Al-PAM and Al-PAM/dispersant system was determined to be 70% and 66% at ash content of 7.74% and 7.4%, respectively. Zeta potential values of both the raw coal and concentrate products showed a large shift toward more positive values (from ˉ50 mV to ˉ13 mV), indicating a significant decrease in ash-forming minerals (slimes) when Al-PAM polymers were applied....
摘要:In this study, the production of synthesis gases has been purposed under between 250oC - 700oC and 1 - 2 bars pressures. The research was conducted over a commercial BASF catalyst and a laboratory prepared catalyst. The catalyst has a content of different substances including basically NiO/Al2O3 and some additionals (Ca, Mg, Cr, Si). The experimental measurements were carried out within a recently developed experimental equipment which can be operated up to 1200o and 1 to 3 bars pressures. The study was conducted over a commercial BASF catalyst and a laboratory prepared catalyst under different ethanol/water ratios, temperatures, and catalyst loads. Under the condition when ethanol/water ratios were decreased from 1/2 to 1/10, it was observed that hydrogen ratios increased in exit gas composition of the reactor. With increments in catalyst loads from 1 to 5 grammes, hydrogen ratios in exit gas composition gradually increased. Reaction of ethanol-steam reforming started nearly at 300oC, and when temperature increments continued further up to 700oC, hydrogen yields in exit gas compositions of the reactor increased significantly to a range of 70% - 80%. In the case of using commercial BASF catalyst, hydrogen ratios in exit gas composition were found slightly higher than laboratory prepared catalyst. According to our observations, life time of laboratory prepared catalyst was found higher than the commercial BASF catalyst. In this study which kinetic measurements were applied, some kinetic parameters of ethanol-steam reaction were calculated. The mean activation energy of ethanol consumptions at 573oK - 973oK was found as 26.87 kJ/mol, approximately. All kinetic measurements were analyzed with a first order reaction rate model. In this study, some diffusion limitations existed, however, overall reaction was chemically controlled....
摘要:Mine Plant 2 is a part of the Ostrava-Karvina Coal District (OKD) that is located in the Czech part of the Upper Silesian Basin. The first coal was exhausted from Mine Plant 2 in 1968. The most used method of mining so far in this area has been strike longwall mining with controlled caving. Due to extensive changes in the surface, which occur as a consequence of deep mining by the method of longwall mining with controlled caving, it is not possible to use this method in densely populated areas. At the present time, therefore, the trial operation of a new mining method called room and pillar is carried out. The method was chosen with the aim to minimize subsidence and deformations of the surface. The room and pillar mining method has never been used before in the conditions of the OKR, therefore it is necessary to prove the real effect of mining by this method on the surface. For this purpose, a surface observation station was designed, consisting of 36 surface points. The position and height of all points of the observation station is determined in stages three times a year....
摘要:The goal of this work is to evaluate and to give evidence to innovative and sustainable technologies applied in the construction industry to carry out self-sufficient energy and to use the surplus energy for the production of hydrogen vector. An architectural integration design along with high technological systems is performed. The intermittency of renewable energy sources along with climatic conditions dependency imposes to store the energy produced, since it is clean and having a big calorific value: the hydrogen vector is currently the better energy carrier. The energy to obtain hydrogen by dissociation of water is supplied by a photovoltaic (PV) system. Through the computations of the annual energy balance between building’s demand and supply energy, it is shown that the extra energy produced by the solar generation system is used also for the hydrogen sustainable mobility. The renewable systems, model’s design and case study are tackled for the bigger one of the Dodecanese islands in the South Aegean Sea: Rhodes (Rodos). The Zero energy building’s integrative design-based approach, applied to the Hotel Buildings type industry is targeted to have new hotels buildings, in the Mediterranean typical warm climate, with zero energy consumption. The designers, authors of this work, have studied a real case or pilot project of an hotel, in the resort formula, suitable to the Greek landscape, showcasing technologies and innovations supporting environmental sustainability, energy efficiency, use of renewable energy, electricity storage by fuel cells that are tools particularly applicable to hotel facility [1]. The feasibility of this case study or pilot project is aligned jointly to the target of Zero Emission and Energy Efficiency EU Policy, as imposed by EU Directives. The strategic position of Rhodes in a geographical point full of sun and wind renewable energy power, enables to ensure the clean energy production, the current interesting development of the hydrogen as energy vector in the buildings [2] and also to satisfy the demand of tourists’ accommodation by having at the same time zero energy costs. Moreover, the presence in the island of the best example worldwide of ancient and sustainable built environment (UNESCO World Heritage site), represents also the best motivation to give witness there of a zero impact environmental urban development through the adoption of these achieved scientific results for a major success of Zero Energy Buildings....
摘要:The goal of this work is to evaluate and to give evidence to innovative and sustainable technologies applied in the construction industry to carry out self-sufficient energy and to use the surplus energy for the production of hydrogen vector. An architectural integration design along with high technological systems is performed. The intermittency of renewable energy sources along with climatic conditions dependency imposes to store the energy produced, since it is clean and having a big calorific value: the hydrogen vector is currently the better energy carrier. The energy to obtain hydrogen by dissociation of water is supplied by a photovoltaic (PV) system. Through the computations of the annual energy balance between building's demand and supply energy, it is shown that the extra energy produced by the solar generation system is used also for the hydrogen sustainable mobility. The renewable systems, model's design and case study are tackled for the bigger one of the Dodecanese islands in the South Aegean Sea: Rhodes (Rodos). The Zero energy building's integrative design-based approach, applied to the Hotel Buildings type industry is targeted to have new hotels buildings, in the Mediterranean typical warm climate, with zero energy consumption. The designers, authors of this work, have studied a real case or pilot project of an hotel, in the resort formula, suitable to the Greek landscape, showcasing technologies and innovations supporting environmental sustainability, energy efficiency, use of renewable energy, electricity storage by fuel cells that are tools particularly applicable to hotel facility [1]. The feasibility of this case study or pilot project is aligned jointly to the target of Zero Emission and Energy Efficiency EU Policy, as imposed by EU Directives. The strategic position of Rhodes in a geographical point full of sun and wind renewable energy power, enables to ensure the clean energy production, the current interesting development of the hydrogen as energy vector in the buildings [2] and also to satisfy the demand of tourists' accommodation by having at the same time zero energy costs. Moreover, the presence in the island of the best example worldwide of ancient and sustainable built environment (UNESCO World Heritage site), represents also the best motivation to give witness there of a zero impact environmental urban development through the adoption of these achieved scientific results for a major success of Zero Energy Buildings....
摘要:The catalytic pyrolysis of lignites is a technical process whose development is complex and time-consuming with the goal to maximize the yield of the desired low-volatile hydrocarbons of choice and to minimize the yield of solid residual products. Not every type of lignite is suitable for this process due to its particular chemical composition. In order to be able to predict which lignite specimen will be an especially promising raw material for the pyrolytic liberation of target products, the chemical classification by IR spectroscopic methods was investigated. MIR spectroscopy has been demonstrated to be a valuable tool to characterize the the molecular composition of lignites and to determine the concentrations of aliphatic and aromatic functional groups in lignite as well as alcoholic OH and other forms of bound oxygen. These data provide a comprehensive chemical characterization of the material and help to predict the composition of the chemical components liberated by catalytic decomposition. With a complementary NIR spectroscopic approach, a chemometric method has been developed with which the elemental com-position of the lignites can be determined in a fast and pragmatic way leading to a prediction of the product range of a theoretical pyrolytic product range. Thus, this spectroscopic investigation is a toolbox that can answer the question if the commercial exploitation of catalytic pyrolysis of a lignite sample in question will make sense without preliminary conduction of long and time-consuming testing....
摘要:Coal is a dirty fuel contaminated with F- and other elements. Several million tons of coal are burnt in Korba basin, central India to generate electricity with pouring fluorine and other elements into the environment. The water is contaminated with F- and other chemicals beyond the permissible limits. The contaminated water is consumed by the human and animals by excreting the balanced toxicants through the stool and urine. Several folds higher concentration of F- in urine (44 mg/L) and stool (266 mg/kg) samples of the cattle are observed. The prevalence of fluorosis diseases in cattle of the Korba basin is reported....
摘要:Mine Plant 2 is a part of the Ostrava-Karvina Coal District (OKD) that is located in the Czech part of the Upper Silesian Basin. The first coal was exhausted from Mine Plant 2 in 1968. The most used method of mining so far in this area has been strike longwall mining with controlled caving. Due to extensive changes in the surface, which occur as a consequence of deep mining by the method of longwall mining with controlled caving, it is not possible to use this method in densely populated areas. At the present time, therefore, the trial operation of a new mining method called room and pillar is carried out. The method was chosen with the aim to minimize subsidence and deformations of the surface. The room and pillar mining method has never been used before in the conditions of the OKR, therefore it is necessary to prove the real effect of mining by this method on the surface. For this purpose, a surface observation station was designed, consisting of 36 surface points. The position and height of all points of the observation station is determined in stages three times a year....
摘要:In this study, the production of synthesis gases has been purposed under between 250oC - 700oC and 1 - 2 bars pressures. The research was conducted over a commercial BASF catalyst and a laboratory prepared catalyst. The catalyst has a content of different substances including basically NiO/Al2O3 and some additionals (Ca, Mg, Cr, Si). The experimental measurements were carried out within a recently developed experimental equipment which can be operated up to 1200o and 1 to 3 bars pressures. The study was conducted over a commercial BASF catalyst and a laboratory prepared catalyst under different ethanol/water ratios, temperatures, and catalyst loads. Under the condition when ethanol/water ratios were decreased from 1/2 to 1/10, it was observed that hydrogen ratios increased in exit gas composition of the reactor. With increments in catalyst loads from 1 to 5 grammes, hydrogen ratios in exit gas composition gradually increased. Reaction of ethanol-steam reforming started nearly at 300oC, and when temperature increments continued further up to 700oC, hydrogen yields in exit gas compositions of the reactor increased significantly to a range of 70% - 80%. In the case of using commercial BASF catalyst, hydrogen ratios in exit gas composition were found slightly higher than laboratory prepared catalyst. According to our observations, life time of laboratory prepared catalyst was found higher than the commercial BASF catalyst. In this study which kinetic measurements were applied, some kinetic parameters of ethanol-steam reaction were calculated. The mean activation energy of ethanol consumptions at 573oK - 973oK was found as 26.87 kJ/mol, approximately. All kinetic measurements were analyzed with a first order reaction rate model. In this study, some diffusion limitations existed, however, overall reaction was chemically controlled....
摘要:The catalytic pyrolysis of lignites is a technical process whose development is complex and time-consuming with the goal to maximize the yield of the desired low-volatile hydrocarbons of choice and to minimize the yield of solid residual products. Not every type of lignite is suitable for this process due to its particular chemical composition. In order to be able to predict which lignite specimen will be an especially promising raw material for the pyrolytic liberation of target products, the chemical classification by IR spectroscopic methods was investigated. MIR spectroscopy has been demonstrated to be a valuable tool to characterize the the molecular composition of lignites and to determine the concentrations of aliphatic and aromatic functional groups in lignite as well as alcoholic OH and other forms of bound oxygen. These data provide a comprehensive chemical characterization of the material and help to predict the composition of the chemical components liberated by catalytic decomposition. With a complementary NIR spectroscopic approach, a chemometric method has been developed with which the elemental com-position of the lignites can be determined in a fast and pragmatic way leading to a prediction of the product range of a theoretical pyrolytic product range. Thus, this spectroscopic investigation is a toolbox that can answer the question if the commercial exploitation of catalytic pyrolysis of a lignite sample in question will make sense without preliminary conduction of long and time-consuming testing....
摘要:Coal is a dirty fuel contaminated with F- and other elements. Several million tons of coal are burnt in Korba basin, central India to generate electricity with pouring fluorine and other elements into the environment. The water is contaminated with F- and other chemicals beyond the permissible limits. The contaminated water is consumed by the human and animals by excreting the balanced toxicants through the stool and urine. Several folds higher concentration of F- in urine (44 mg/L) and stool (266 mg/kg) samples of the cattle are observed. The prevalence of fluorosis diseases in cattle of the Korba basin is reported....
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