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This study made observations on mineralogy, petrological, and petrographic textures related to diagenesis and traces of methane presence in cuttings samples in sedimentary rock in well XS-01, Makassar Strait, Indonesia. The research methods carried out included a description of the cuttings sample, XRD, and petrography aimed at obtaining information on mineralogy, petrology, and diagenesis aspects of rocks, as well as documenting petrographic texture of the presence of methane in samples that prove the presence of methane in the recent past. The results showed that the identified mineralogy are calcite, quartz, amorphous silica, kaolinite, and montmorillonite. The rock types include claystone, siltstone, wackestone, packstone, and crystalline limestone. There are three (3) petrographic textures related to diagenesis: fracturing, calcite cementation, and silicification. Cement is drusy calcite and amorphous silica, representing the diagenesis stage of mesogenesis. The micrite petrographic texture shows as clotted peloidal micrite in wackestone, which was interpreted as a product of microbial activity during carbonate mineral precipitation stimulated by the Anaerobic Oxidation of Methane (AOM) process. This texture indicates the remnant of methane that characterizes the biogenic gas from the chimney gas zone. The gas chimney is common geological structures within the subsurface realm, which is recorded on the seismic sections.very easy to see or easily distinguished from other geologic features on the seismic section. However, the characterization of mineralogy, petrology, and petrographic textures is still rarely found in the literature due to limited accessibility to the interior of gas chimneystill quite rare. In this study, observations were made on mineralogy, petrological, and petrographic textures related to diagenesis and traces of methane gas presence in cuttings samples in sedimentary rock in well XS-01, Makassar Strait, Indonesia. The research methods carried out included a description of the cuttings sample, XRD test, and thin-section petrography aimed at obtaining information on mineralogy, petrology, and diagenesis aspects of rocks, as well as document-ing petrographic textures of traces of the presence of methane gas in samples that prove the presence of methane gas in the recent past. The results showed that the identified mineralogy are calcite, quartz, amorphous silica, kaolinite, and montmorillonite. The rock types include claystone, siltstone, wackestone, packstone, and crystalline limestone. There are three (3) petrographic textures related to diagenesis, namely fracturing, calcite cementation, and silicification. Cements are, with the types of cement including drusy calcite and amorphous silica which represent the diagenesis stage of mesogenesis. The micrite petrographic texture shows as clotted peloidal micrite in wackestone which were interpreted as a product of microbial activity during carbonate mineral precipitation stimulated by the Anaerobic Oxidation of Methane process. This texture is an indicator of remnant of methane that characterizes the biogenic gas from the chimney gas zone. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) are a technology of high efficiency that is often applied in stacks for modern cogeneration systems as a standalone unit, or hybridized with an internal combustion engine (ICE) or a gas turbine (GT). Such systems successfully process different types of carbohydrate fuels and have close to none local emissions. Simultaneously, SOFCs are faintly available on the market of fuel cells today, and the processes and technologies used for their production and testing are not as popular as those of proton exchange membrane fuel cells (PEMFCs). Thus, in order to better understand the nature and working principles of SOFCs, and to optimize their performance in order to better select and possibly produce a stack with the appropriate working characteristics for a concrete application, a mathematical simulation needs to be performed. This article describes a 0-D steady state model of the reforming and electrochemistry of a low-powered, intermediate temperature, anode-supported planar SOFC stack. The model uses internal reforming with 100% methane as fuel and air as oxidant. The stack is intended for a hybrid power generation system with a low-powered ICE (up to 2 kW) for realization of a bottoming or a combined cycle. The main purpose of the model is to determine a suitable single-cell and stack parameter layout with power also up to 2 kW, based on the comparison of the polarization curves, efficiency, power, and the energy contained in the anode off-gas of the cells in the stack. The varied parameters in the study are operating temperature, operating pressure and fuel utilization factor of the stack. The results show that a stack with T=750 °C, p=1 bar, and Uf=0.75 gives the most favorable characteristic in terms of compromise between performance, cost, stable operation and heat management. [ABSTRACT FROM AUTHOR]

The work presents the results of thermodynamic calculation of the composition of the mixture obtained during the conversion of methane steam carbon dioxide water vapor, carbon dioxide and methane mixture into synthesis gas. As a result of research, it was determined that the minimum value of the conversion temperature of the mixture of water vapor, carbon dioxide and methane to synthesis gas to obtain synthesis gas acceptable for the synthesis of liquid hydrocarbons by the Fischer-Tropsch method is 800°C. The experiments were carried out at a temperature of 450°C in the mixing chamber and 900°C in the reaction zone of the components of the initial gas mixture of different contents of the gas mixture. The temperature in the reaction zone was determined by the strength characteristics of the heat-resistant alloy of the reactor vessel designed to obtain synthesis gas consisting of a mixture of water vapors of methane and carbon dioxide. Data obtained as a result of the experiment show that the proposed technology of conversion of a mixture of methane water vapor, carbon dioxide and methane into synthesis gas allows obtaining synthesis gas with a ratio of hydrogen to carbon dioxide from 1.5 to 4.5. The selectivity of H2 and CO increases by more than 10% with the increase of the conversion temperature of the mixture of water vapor, carbon dioxide and methane to synthesis gas from 800 to 850°C, and it does not change much when the temperature increases from 850 to 900°C. The yield of H2 and CO increases with increasing temperature from 800 to 850°C and remains practically constant with increasing temperature from 850 to 900°C. In the temperature range from 800 to 900°C, the conversion rates of the mixture of CH4 water vapor, carbon dioxide and methane to synthesis gas remain practically unchanged. [ABSTRACT FROM AUTHOR]

In the article, the degree of conversion of methane and carbon dioxide, as well as the dependence of the selectivity for hydrogen on the flow rate of the initial mixture for the process of converting methane to carbon dioxide in a membrane (shell, curtain) reactor designed for the conversion of methane to synthesis gas of the "distributor" type at different temperatures is studied. At the same time, the conversion of methane and carbon dioxide was compared in "contactor" and "distributor" type (T=910°C) membrane (shell, curtain) reactors designed for synthesis gas by conversion of methane. The conversion of methane and carbon dioxide, as well as the observed hydrogen selectivity during the conversion process, in different types of membrane (shell, curtain) reactors designed for the conversion of methane to synthesis gas ("contactor" and "distributor") and in the usual reactor for the conversion of methane to synthesis gas compared. Contactor and distributor membrane (shell, curtain) hydrogen selectivity for reactors designed to obtain synthesis gas by conversion of methane was compared. When comparing the ratio of the reaction products of the mole ratio of hydrogen to carbon dioxide to the conversion of methane to carbon dioxide, then in the case of the "contactor" it does not exceed 0.6 (due to the occurrence of a side reaction), and for the "distributor" it exceeds one for all volumetric flow rates of the initial reactants. [ABSTRACT FROM AUTHOR]

A numerical study on the effects of air/fuel configuration on NOx emissions control using methane fuel combustion at different thermal intensity was conducted in this paper. The investigation employed the structure of small combustors which are influenced by some combustion factors. The layout is produced through diverse air and fuel injection configurations selected due to their potential on distinct combustion characteristics. In reverse configurations mode, the air injection port is located at the exit end of the combustor; while in the forward configurations, the air injection port is placed at the reversed end of the combustor exit, with a change of fuel position. Our investigation indicated that in both non-premixed and premixed combustion modes, the NOx discharge is extremely low. However, in premixed combustion mode, the forward and reverse flow configuration (FP, RP) premixed produced a significantly low level of NO and CO compared to the other air configurations in non-premixed at all equivalence ratios Φ The investigation observed that any changes to the fuel injection position affect the mixture preparation, resulting in premature combustion at very low emissions, hot spots and increased emissions. The reverse-cross-flow configuration (RC1) has more potential to attain lower NO (approximately 1.30E-05 ppm) together with low CO (approximately 223 ppm) emissions when compared to the other flow configuration (RC2 and RC3). More so, a lower combustor volume leads to a very high thermal intensity of 324–393 MW/m3-atm thus resulted in a reduced residence time and gas recirculation, and high CO and NOx emissions. [ABSTRACT FROM AUTHOR]

The essence of the method is the interaction of nitrate mixtures of metals included in the catalyst and the organic matter in the air at temperatures ≥500 ℃. The reaction is followed by the formation of finely dispersed oxides of metals. The reaction is followed by the formation of finely dispersed oxides of metals. It allows calculating the concentration of system components not only at the outlet of the apparatus but also along the length of the reactor. As a result, the methane supplied to the surface of the catalyst manages to interact with it before methane escapes with a stream of the initial gas mixture. The kinetic curves of the time dependence of the change in the specific amount of carbon in the catalyst do not have an induction period at all. [ABSTRACT FROM AUTHOR]

Methane (CH4) is one of the main constituents of landfill gas (LFG), which is produced through anaerobic degradation of Municipal Solid Waste (MSW). It is also regarded as the most anthropogenic greenhouse gas emission source. Quantification of CH4 emission is essential in order to gain a perception about the LFG recovery potential of a particular landfill area. This paper envisages the estimation of methane emission from Rajbandh landfill area in Khulna city where the emission from year 2020 to 2050 has been calculated using two distinct methodologies, namely IPCC 2006 and LandGEM. The IPCC 2006 methodology has been used in the algorithm for developing the system dynamics model for methane emission, whereas precisely for LandGEM extensively calculated spatially varied parameters has been used. According to the simulated results from the system dynamics model, the emitted methane from Rajbandh landfill area in Khulna city has been found to be 8.29 Gigagram for the base year of 2020 and by 2050 it has increased to 59.447 Gigagram. From LandGEM the CH4 quantity has been found to be 7.15 Gigagram which by 2050 identically increased to 52.258 Gigagram. The variance ratio or statistical F-test value of the extracted results from both the method showed an acceptable variance of 1.12. The paired sample (t-test) represented a P value less than 0.0001, which represents the statistical significance of the compared dataset from both system dynamics and LandGEM model. Finally, from the system dynamics model, it has been observed that the methane accumulation in atmosphere reached 108 Gigagram by 2050, which indicates the shear requirement of LFG recovery mechanics for a sustainable MSW management system of Khulna city. [ABSTRACT FROM AUTHOR]

It is based on combination of theoretical and empirical approaches; combustion chamber design is not precise science. Three-dimensional simulations are used to examine the velocity profiles, species concentration, and temperature distribution inside combustion chamber using methane as fuel (CH4). It tries to establish fair equilibrium between conflicting elements of intricate physical and chemical interactions flow, which may be quite complex. SST turbulence model is based on non-orthogonal curvilinear coordinates; second order accurate discretization, tetra grid iterative solution process and tetra grid iterative solution procedure. An effort has been made in current research utilising ANSYS CFX 12 to evaluate flow pattern with in combustion and via air entry openings. [ABSTRACT FROM AUTHOR]

The combustion of preheated ultra-lean dimethyl ether/air mixture was investigated numerically. A laminar burner stabilized flame of preheated ultra-lean dimethyl ether was stabilized by methane co-flow and combustion respectively. Steady burning of co-flow methane ensured ignition of dimethyl ether/air mixture at temperature ca 330 °C. A detailed reaction mechanism of dimethyl ether low-temperature combustion and methane combustion were applied in the two-dimension axisymmetric numerical simulation. The state-of-the-art low-temperature chemistry of dimethyl ether and methane was applied in numerical simulation. The thermal interaction of flame and solid boundaries was achieved by solid-fluid coupled boundary conditions in numerical simulation. 2D axisymmetric numerical simulation was performed based on the physical measurement and experimental setup. The axial temperature profile of the flame was obtained by experiments and numerical simulation relatively well agreed with the experiment. The chemical radicals, like OH, CH2O, and HO2, occurrence in lean dimethyl/air flame were also obtained by experiment. The computational simulation of flame showed that there was thermal interaction between flames and solid parts of the experimental burner. The dimethyl ether/air mixture was preheated upstream by the thermal conductivity of solid parts. High and Low-temperature combustion zones were identified on the base of results of numerical simulation and the presence of radicals specific for the appropriate type of combustion respectively. [ABSTRACT FROM AUTHOR]

Global warming caused by greenhouse gas (GHG) emissions is a global problem. Solid municipal waste landfills are the third largest source of artificial methane emissions. Methane is one of the greenhouse gases contributing to global warming. The net zero emissions target was set to strike a balance between emissions and anthropogenic GHG disposal by 2050. Methane emissions from active or closed landfills may be reduced by methane oxidation, which is developed as a coating over these landfills. Methane (CH4) is an important gas that causes greenhouse effects on Earth and has an atmospheric warming potential of 28 times higher than carbon dioxide (CO2). The aim of this study is to find out whether cellulose in the biocover contributes to improving the performance of biocover and to decreasing methane emissions. An experiment was conducted in laboratory conditions that studied the effectiveness of biocover developed in the laboratory. Three experimental columns were created with a diameter of 160 mm and a height of 1500 mm. An active compost saturated with water at a thickness of 500 mm was used as a source of methane, a permeable layer of sand at a thickness of 300 mm was further applied and finally covered with biocover. The first biocover consisted of 50% of fine fraction waste, 50% of clay soil. The second biocover consisted of 40% of fine fraction waste, 40% of clay soil and 20% cellulose (shredded paper). Measurements were performed with the CRDS device, Picarro G2508. The measurements were taken weekly for 5 months. [ABSTRACT FROM AUTHOR]

In the energy field hydrogen will be more obvious to use by certain technologies than by direct combustion. The paper presents a conceptual analysis on the use of hydrogen by hydrogen by hydrogenation of carbon dioxide with final product methane, by hydrogenation of carbon dioxide, with the final product of methanol and by injection in certain proportions into the natural gas network. A new application of carbon dioxide hydrogenation is the decarbonisation of flue gases. To this end, conceptual analyses have been carried out for the capture of CO2 from flue gases, including through cascading energy production, required by a significant decrease in pollution. The experimental development for the hydrogenation of carbon dioxide with an experimental pilot plant shall also be submitted. At the same time, the pressure and temperature conditions for the methaneization plants are also presented. References are also made to catalysts of the latest generation, for a high efficiency of the respective hydrogenation processes. With regard to the hydrogenation of carbon dioxide from flue gases, the effect of water vapor and oxygen on the overall efficiency of the process shall also be clarified. By converting carbon dioxide into combustible substances, an important step towards transforming it into an energy vector is taken. This reduces expenditure by storing it and important steps are taken towards a circular energy. [ABSTRACT FROM AUTHOR]

This article presents a review of the existing techniques for the quality improvement or value addition of biogas by means of the enhancement of its methane content. Biogas has been in use in both rural and urban areas for a very long time but with the increase in the demand of energy its up-gradation slowly become inevitable. The best possible way to increase its efficiency is to increase its methane content and to eliminate the other non-performing constituents. In a way it process re-energies the existing biogas and makes it more suitable for advanced applications. This article has tried to summarize the various existing techniques for the value improvement of biogas and has proposed it as a sustainable source of energy. [ABSTRACT FROM AUTHOR]

In Italy more than 7 Mtons of organic solid waste are generated each year, on average 117.29 kg/hab.year The eating habits of the Italian population was studied to identify the most consumed foods. The most consumed foods were used to prepare a representative sample of food waste. Two methods were used to estimate the bio-methane production potential. The first method, calculate the bio-methane production potential based on the concentrations of lipids, carbohydrates and proteins, the second method use the results of the elemental analysis. The characterization results showed a potential for generating bio-methane of 219 ml.CH4/g for method 1 and 534 ml.CH4/gSV for method 2. Considering the generation of food waste in Italy and the potential for bio-methane production results show that it would be possible to produce 1,543.x 106 and 3,092 x 106 m3CH4 for method 1 and 2 respectively and thus For the method 1, it is possible to recovery equivalent energy 50,942 TJ/year and 102,044 TJ/year for method 2. [ABSTRACT FROM AUTHOR]

Natural gas offers several advantages such as clean combustion, high octane number (approximately 120), high availability, and attractive price. Additionally, its relatively high auto-ignition temperature is suitable for higher compression engines.CFD modeling of internal combustion engines is playing an increasingly important role in improving engine design, leading to a reduction in fuel consumption and pollutant emissions, a comprehensive insight into the wide-ranging physics, such as the ignition, combustion chemistry, knock occurrence, power output and efficiency. This paper deals with the simulation of Spark Ignition engine fuelled with methane, a major composition of natural gas by varying the compression ratio. The work involves CFD analysis using trimmed unstructured polyhedral moving grid that would complete four strokes of the engine. The simulation was carried out for compression ratios of 9.5:1, 10.5:1, 11:1, 12:1, 14:1 and 15:1. STAR-CD software package was used for simulation and combustion was carried out using ECFM-3Z model. From the analysis, the knocking of the engine was found at a compression ratio of 15:1. The performance parameters such as Indicated power, Indicated mean effective pressure, Indicated specific fuel consumption are calculated. [ABSTRACT FROM AUTHOR]

The process of removal of hydrogen sulfide from methane in the plasma of a barrier discharge in the presence of octane vapor is studied. The use of octane vapors in the initial mixture with methane and hydrogen sulfide permits to avoid the formation of a deposit on the electrodes of the plasma-chemical reactor. The degree of hydrogen sulfide removal reaches 98%, the methane conversion does not exceed 10%. Energy consumption for hydrogen sulfide removal is 83 kW h/kg. The main gaseous products of the treatment of the initial mixture in the barrier discharge are hydrogen (30%) and ethane (30%). Among sulfur-containing products, mainly mono- and dialkylsulfides are identified. A possible mechanism of the process is presented. [ABSTRACT FROM AUTHOR]

The effect of coal additives on the properties of the Mo/HZSM-5 catalyst is described. The effect on the physicochemical, texture, adsorption and catalytic properties of the catalyst is investigated. The investigation is carried out using the methods of IR spectroscopy, X-ray phase analysis, and low-temperature nitrogen adsorption. Water vapor adsorption is carried out using a laboratory bench. The methane conversion is studied using a flow-through laboratory apparatus. It is found out that the addition of coal significantly increases the adsorption capacity and the rate of adsorption of zeolites in water vapor and also stabilizes the operation of the catalyst over time. [ABSTRACT FROM AUTHOR]

Spatial distributions of positively charged species naturally occurring in the stoichiometric and fuel-rich premixed H2/CO/O2/Ar flames are measured with molecular beam mass spectrometry. The hydronium (H3O+) ion and its clusters are found to be most abundant cations in the flames. The ion chemistry model proposed earlier by Belhi et al. (2018) for lean methane flames is validated against the measurement data. The model was found to adequately predict the observed tendencies in the flames, once the exact mixture composition, including hydrocarbon impurities (∼5 ppm), is considered. [ABSTRACT FROM AUTHOR]

A 16.77 kW thermal power bayonet-tube reactor for the mixed reforming of methane using solar energy has been designed and modeled. A test bench for the experimental tests has been installed at the Synlight facility in Juelich, Germany and has just been commissioned. This paper presents the solar-heated reactor design for a combined steam and dry reforming as well as a scaled-up process simulation of a solar reforming plant for methanol production. Solar power towers are capable of providing large amounts of heat to drive high-endothermic reactions, and their integration with thermochemical processes shows a promising future. In the designed bayonet-tube reactor, the conventional burner arrangement for the combustion of natural gas has been substituted by a continuous 930 °C hot air stream, provided by means of a solar heated air receiver, a ceramic thermal storage and an auxiliary firing system. Inside the solar-heated reactor, the heat is transferred by means of convective mechanism mainly; instead of radiation mechanism as typically prevailing in fossil-based industrial reforming processes. A scaled-up solar reforming plant of 50.5 MWth was designed and simulated in Dymola® and AspenPlus®. In comparison to a fossil-based industrial reforming process of the same thermal capacity, a solar reforming plant with thermal storage promises a reduction up to 57 % of annual natural gas consumption in regions with annual DNI-value of 2349 kWh/m2. The benchmark solar reforming plant contributes to a CO2 avoidance of approx. 79 kilotons per year. This facility can produce a nominal output of 734.4 t of synthesis gas and out of this 530 t of methanol a day. [ABSTRACT FROM AUTHOR]

The reaction of indoles with carbonyl compounds in the presence of 5 mol% Meglumine Sulphate (MS) in acetonitrile was executed to synthesize bis(indolyl)methane derivatives using conventional and ultrasonication methods. The reaction proceeded in shorter reaction time in ultrasonication methodology leading to high yield of the products. [ABSTRACT FROM AUTHOR]

Biogas is one of promising renewable fuel produced from several numbers of organic substrates. In fact, biomass as the organic matters has an opportunity to generate a cheaper and cleaner energy than using other resources. Therefore, many researchers have been studied about the production of biogas from various kinds of biomass. In Indonesia, there are many cows and lemongrass in nature. Therefore, this study is focused on the utilization of cow manure and lemongrass as the substrate for the production of biogas. The purpose of this study is to obtain the optimum condition of biogas production, including composition of the substrate and temperature of the bio digester. Besides, the addition of rumen bacteria was also investigated in this study. The composition of cow manure and lemongrass were varied at the ratio of 1:0, 3:1, 1:1, 1:3 and 0:1 in weight. The temperature of bio digester was also varied at room temperature, 39℃, and 50℃. Result shows that the volume of biogas produced by using lemongrass was less than using cow manure. However, the mixture of cow manure and lemongrass improved the quality and quantity of biogas produced. Based on the results, the highest volume of biogas at 890 mL and the highest percentage of methane at 14.90 % were produced from the composition of substrate with the ratio of 1:1 at the temperature of 50℃ with the addition of rumen bacteria. It was revealed that the higher temperature of bio digester was better for the production of biogas in the range of room temperature to 50℃. It was also proved that rumen bacteria are important for the production of biogas. [ABSTRACT FROM AUTHOR]

Methane is one of the most useful gas that can be used directly as fuel. Nevertheless, toxic gas emission after used is still at high number while its efficiency is still very low. On the other hand, methane can be converted to methanol via partial oxidation reaction for further use. In this study, HY zeolite, synthesized from kaolin impregnated with iron (III) oxide, were used as catalysts in methane partial oxidation reaction. Two types of HY zeolite were synthesized with or without additional cetyltrimethylammonium bromide as secondary template, which were labeled as hierarchical and microporous Y zeolite, respectively. Then, both zeolites were modified via cation exchange with NH4+ and impregnated with iron (III) oxide which produced Fe2O3/HY after calcined at 550 °C. As comparison, Y zeolites were also prepared using synthetic precursors such as colloidal silica and sodium aluminate. All materials then were analyzed with X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and infrared spectroscopy (FTIR). The XRD analysis showed that both as-synthesized Y zeolites had similar pattern to standard zeolite Y. The FTIR analysis also showed that both zeolite have all peaks attributed to functional groups in Y zeolite. Application test was carried out on each catalyst towards the conversion of methane to methanol by using methane pro analysis as the source of methane and reacted in atmospheric fixed batch reactor with the ratio of CH4 and N2 (0.5 % O2) is 0.075:2 Bar. Reaction is performed at 150 °C for 120 min. Products of each reaction was analyzed with GC-FID to know the percentage of methanol yield. The results showed that the % yield of methanol was similar for all catalysts, in which Fe2O3/microporous HY-syn gives as high as 19.11 %, then 18.73 % from Fe2O3/hierarchical HY-nat, 18.60 % from Fe2O3/hierarchical HY-syn, and 18.46 % from Fe2O3/microporous HY-nat. [ABSTRACT FROM AUTHOR]

By setting clear targets for reducing pollutant emissions, the researchers in the field of combustion are pushed lately to find new alternatives for cleaner combustion. The partial or total transition to other types of fuels, such as hydrogen, involves substantial changes in the combustion process and possible necessary constructive changes. In the study of the combustion of CH4 -H2 mixtures, both numerically and experimentally, preliminary calculations are required, which will help to easily establish the parameters and working regimes and then to use for verifying the results. This paper aims to find an easier method of calculating these parameters, depending on the percentage of gas in the fuel mixture. The calculated values resulted this way will lead to some logical estimates of important aspects of combustion, such as flame field and temperature variation, related to the variation of the amount of hydrogen in the mixture. The method can be a useful tool in the preliminary design of a combustion chamber for CH4 -H2 mixtures. [ABSTRACT FROM AUTHOR]

Development of marine engine technology is driven increasingly by strict emissions regulations. Dual fuel technology which uses natural gas as supporting fuel is a smart solution due to it is cleaner, cheaper and can reduces dependency on fossil fuel oil. However the phenomenon of methane slip is the biggest challenges on applications of diesel – natural gas dual fuel engine. A large amount of fuel with poor oxygen especially when engine on low load condition make some parts of methane were unburned, these uncompleted combustion raises methane slip. Meanwhile crevice or dead volume in the cylinder make gas trapped and come out as exhaust gas without participating on combustion. It is evident that being the same greenhouse gases the effect of methane slip is more dangerous than CO2 causing global warming and climate change. This research was carried out experimentally to find out how the natural gas injection time affected on the combustion performance and methane slip. On this study, three variation pulse width as injection timing of natural gas 260° BTDC, 230° BTDC and 214° BTDC were investigated to single cylinder diesel engine on constant speed 2000 rpm. The pressure of gas injection was taken fixed 3 bar, while the pilot injection timing was constant at 18 BTDC. From 30 cycles analyzed at each injection time, a significant relationship was found between optimizing the gas injection time and the gas duration to the methane slip value. Backing the injection time towards the closing of the intake valve with the right injection duration can reduce the value of methane slip. Although the 260° BTDC injection time in this research is optimal compared to the others due to the CNG wasted due to the duration of the injection that passes through the intake valve. [ABSTRACT FROM AUTHOR]

The novelty of the research was that the transformations were carried out in a pulsed mode at small contact times. A rise in temperature increases the amount of activated methane but decreases the H/C ratio in the surface hydrocarbon fragments. The optimal contact time of methane with the catalyst is in the range from 1 to 2.5 s. It provides the required methane activation depth and, which is most important, the optimal H/C ratio in the surface hydrocarbon fragments CHx equal to 3 at./at. An increase in the amount of strong LAS (a.b. at 2200 cm-1 and higher) in the support enhances methane activation at a considerable decrease in the H/C ratio in the surface hydrocarbon fragments, whereas a substantial increase (in the case of Pt/Al2O3-F, up to 150 μmol/g) deteriorates the activity toward methane activation and the H/C ratio. [ABSTRACT FROM AUTHOR]

According to Regulation of the Minister of Environment of December 29, 2016, on the detailed method of selective collection of selected waste fractions, selective collection of biowaste is mandatory. Biowaste stream can consist of both kitchen waste and biodegradable waste from gardens and parks. Kitchen waste and “green waste” can be selected separately or collectively. Properties of kitchen waste and green waste can differ significantly. Considering fermentation as the main treatment method for these types of waste, the biggest difference between green and kitchen waste are the organic matter content, and the type of polymers forming it. Because of that initial study of biowaste, the collection system's influence on methane production was performed. For this purpose, three types of biowaste were investigated. Separately collected kitchen bio waste, green biowaste and its mixture. This approach will allow analyzing both separate and joint collection system. The result indicated that kitchen waste exhibited the highest methane yield reaching 435 m³·kg-1 (total solids) which was more than 6 times higher compared to the result obtained for green waste. Obtained data may help to decide the best approach for treating biowaste collected in separate systems. [ABSTRACT FROM AUTHOR]

In Brazil, about 12 million tons of rice is produced annually, among the types of rice produced is parboiled rice, which according to data from the Brazilian Association of the Parboiled Rice Industry represents 23% of Brazil's rice consumption. In the production of parboiled rice, a hydrothermal process is carried out in which the rice is subjected to a period of waterlogging, followed by autoclaving and subsequent drying, with the diffusion of nutrients from the bark to the interior of the grains, also occurring at the same time leaching of several compounds for the water of waterlogging. Thus, the parboiling of rice has high generation of effluent rich in organic matter, for each kilogram of rice subjected to the parboiling process are generated of two to four liters of effluent. One of the treatments used in Effluent Treatment Stations for the removal of organic matter from this effluent is the anaerobic digestion process, during this biological treatment occurs generation of sludge. In anaerobic digestion a several groups of microorganisms interact in the conversion of complex organic matter to methane, carbon dioxide, water, hydrogen sulphide and ammonia, the energy for the own growth, that is forming the anaerobic sludge. The sludge can be use as inoculum in others process of anaerobic digestion for production of biogas and methane for generation of energy, an important parameter to be considered for better control of the anaerobic digestion process is the maximum efficiency in the production of methane which can be obtained by the test of Specific Methanogenic Activity (SMA). The test can be defined as the maximum capacity of methane production by a consortium of anaerobic microorganisms, carried out under controlled laboratory conditions, to enable the maximum biochemical activity of conversion of organic substrates to biogas. This study had an objective to evaluate the specific methanogenic activity of parboiled rice sludge. The biodigesters used for the test was fed with sludge, ideal macro and micronutrient solutions, glucose solution, sodium bicarbonate and distilled water. The test occurred for a period of 144 hours and quantification of the volume of methane generated was performed based on the principle of displacement of fluids. The Chemical Oxygen Demand analysis required for the determination of SMA was performed according to Standard Methods for the Examination of Water & Wastewater and the total solids, fixed and volatile according to the norm NBR 10664.The SMA obtained in this study was 1.396E-05 gCODCH4(gVSSh)-1 [ABSTRACT FROM AUTHOR]

The anaerobic fermentation of biomass in methane-tank during the biogas production is considered. The process of individual bubbles lifting upwards and its simultaneous interaction with solid particles with mixing of the nascent substrate is analyzed. The forces acting on the bubble are given and a differential equation is developed that characterizes the biogas bubble movement in the organic mass substrate. The mathematical dependence of the flooding rate of the biogas bubble is developed and an example of solving the differential equation is given. Productivity of biogas production is determined by the rate of bubble burst and its concentration. Biogas volume modeling is carried out under the following conditions: 54-56 °C fermentation temperature, 99% humidity, absolute dry organic matter content is 0,2-0,35 kg, 5 m3 methane tanks, degree of decomposition of organic mass is 40%, methane content in biogas is 65%. The results of modeling of biogas production productivity are presented. [ABSTRACT FROM AUTHOR]