Use Of Methane Research Articles

Development of mathematical model for predicting methane-to-carbon dioxide proportion in anaerobic biodegradability of cattle blood and rumen content

• Prediction of methane-to-carbon dioxide within mesophilic range. • Production of methane for use as renewable energy source. • Optimal methane-to-carbon dioxide ratio in relation to temperature and hydraulic retention time. The potential of methane yield depends on the composition of feedstock which is characterized by a diversity of biodegradable fractions. This study aims at constructing and using the novel kinetic model as a tool to predict methane-to-carbon dioxide ratio from slaughterhouse solid waste using hydraulic retention time and temperature as parameters. The slurries prepared were composed of cattle blood, rumen content and requisite nutrient solution which were fed into a continuously stirred tank reactors. The process was monitored at regular intervals of 3 days for a retention time of 54 days for thermostatically controlled temperatures of 35, 37 and 40 °C. The percentage methane and carbon dioxide gas concentrations in the headspace were measured. The phenomenon was idealized with scatter plots and co-efficient of determination used to establish a reasonable correlation between the identified parameters. In this study, simple, robust and reliable kinetic models have been developed using the Microsoft Excel Add-in Solver Tool with the Generalized Reduced Gradient. The optimum solution of seven unknown constants represented by adjusted values where simulated values adequately matched the observed values for the three zones of this study. Validation of the models also showed that the phenomenon can be produced in a continuum at any fixed temperature.

Comparison of Methods to Measure Methane for Use in Genetic Evaluation of Dairy Cattle.

Simple SummaryMethane is a greenhouse gas with a global warming potential 28 times that of CO2. Enteric methane accounts for 17% of global methane emissions and 3.3% of total global greenhouse gas emissions from human activities. There is, therefore, significant research interest in finding ways to reduce enteric methane emissions by ruminants. Partners in Expert Working Group 2 (WG2) of the European Cooperation in Science and Technology (COST) Action METHAGENE have used several methods for measuring methane output by individual dairy cattle under various environmental conditions. Methods included respiration chambers, the sulphur hexafluoride (SF6) tracer technique, breath sampling during milking or feeding, the GreenFeed system, and the laser methane detector. Respiration chambers are considered the ‘gold standard’, but are unsuitable for large-scale measurements of methane emissions, which are needed for genetic evaluations. In this study, the suitability of methods for large-scale studies was reviewed and compared. All methods showed high correlations with respiration chambers, but comparisons among alternative methods generally had lower correlations. Results confirm, however, that there is sufficient correlation between methods for measurements from all methods to be combined, with appropriate weightings, for use in international genetic studies. This will pave the way for breeding cattle with lower methane emissions.Partners in Expert Working Group WG2 of the COST Action METHAGENE have used several methods for measuring methane output by individual dairy cattle under various environmental conditions. Methods included respiration chambers, the sulphur hexafluoride (SF6) tracer technique, breath sampling during milking or feeding, the GreenFeed system, and the laser methane detector. The aim of the current study was to review and compare the suitability of methods for large-scale measurements of methane output by individual animals, which may be combined with other databases for genetic evaluations. Accuracy, precision and correlation between methods were assessed. Accuracy and precision are important, but data from different sources can be weighted or adjusted when combined if they are suitably correlated with the ‘true’ value. All methods showed high correlations with respiration chambers. Comparisons among alternative methods generally had lower correlations than comparisons with respiration chambers, despite higher numbers of animals and in most cases simultaneous repeated measures per cow per method. Lower correlations could be due to increased variability and imprecision of alternative methods, or maybe different aspects of methane emission are captured using different methods. Results confirm that there is sufficient correlation between methods for measurements from all methods to be combined for international genetic studies and provide a much-needed framework for comparing genetic correlations between methods should these become available.

Catalytic aromatization of ethylene in syngas from biomass to enhance economic sustainability of gas production

Ethylene aromatization is a novel approach that utilizes gas produced from biomass or waste gasification to facilitate the removal of unsaturated hydrocarbons (precursors of coke in downstream synthesis catalysts) while simultaneously producing a valuable aromatic fraction. The recovery of valuable compounds (ethylene and benzene, toluene, and xylene (BTX)) from biomass-derived syngas effectively improves the economic benefits of the gasification process.This study determined the effects of reaction temperature and Ga loading on the conversion and selectivity of bifunctional Ga–zeolite catalysts for the conversion of ethylene to aromatic compounds. The activity and stability of the synthesized materials were analyzed under realistic gasification conditions by using the gas produced from an indirect gasification process. The maximum ethylene conversion (∼97%) was achieved when 0.025 g/g Ga–zeolite catalyst was used. However, 0.005 g/g Ga–zeolite catalyst exhibited the highest carbon selectivity to benzene (∼32%) and the highest total carbon selectivity to aromatics (73%). The temperature markedly influences the distribution of carbon selectivity to aromatics. Lower temperatures favor the production of ethylbenzene and xylenes, whereas benzene, naphthalene, and naphthalene derivatives are yielded at higher temperatures. The results suggest that benzene formation and toluene formation require different active sites. This study proposes a biomass gasification process to obtain methane for use in industrial applications. Substitute natural gas production ensures economic sustainability by generating in situ high-value-added by-products (aromatics).

Hydropower's Biogenic Carbon Footprint.

Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations.

Mechanism confirmed for methane-making enzyme

In marshes and the guts of some animals, methane-producing bacteria, called methanogens, produce hundreds of millions of metric tons of methane each year. To design improved routes to methane for use as a chemical feedstock or fuel, researchers have long wanted to understand the molecular details of how these microbes generate the important gas. A new study reports data that confirm a proposed mechanism used by a key bacterial enzyme in the methane-making process. The enzyme, called methyl-coenzyme M reductase, catalyzes the final step in methane production, in which an H atom is added to a CH3 group to yield the gas. Methane-oxidizing archaea use the same enzyme to catalyze the reverse process, methane oxidation—a process that uses up less than one-tenth the amount of methane methanogens produce annually. Scientists have been studying the enzyme intensively for about two decades. Experimental studies beginning in the late 1990s favored the so-called

An Evaluation of the Global Potential of Cocoyam (Colocasia and Xanthosoma species) as An Energy Crop

Aims: To evaluate the potential of cocoyam (Colocasia and Xanthosoma species) for the production of ethanol and methane for use as energy sources. Study design: Laboratory experimentation. Place and duration of study: Federal College of Agriculture Ibadan and Institute of Agricultural Research and Training (IAR&T), Moor Plantation, Ibadan, Nigeria between December 2010 and June 2011. Methodology: Five, 15, 25 and 35 kg samples of peeled cocoyam corms were weighed in three replicates. Next, the weighed cocoyam was soaked in clean water for 24 hr, and afterwards placed on a clean tray and allowed to air dry naturally for 4 hr. The cocoyam corms were then cut and the pieces transferred to a mortar where they were mashed to attain sufficient size reduction. The mash was then transferred into a plastic bucket. Five hundred, 650, 800 and 950 ml of N-hexane (C6H14) was added to the 5, 15, 25 and 35kg samples. The mash was thoroughly stirred to achieve an even mixture with the hexane. It was then covered and left undisturbed in the laboratory at room temperature for 8 days. The fermented mash was poured onto a 0.6 mm aperture size sieve and completely squeezed to dryness while the liquid filtered through the sieve. N-hexane was removed from the filtered liquid. The collected liquid was poured into a glass dish and then gradually heated at 79°C for a total of 10 hr (at intervals of 2 hr heating followed by 1 hr cooling) to ensure complete evaporation of any trapped H2O or CO2 remaining in it. Afterwards the final liquid (ethanol) was allowed to cool normally in the lab and its mass, volume and other properties were measured. Results: It was found that ethanol was yielded at the rate of 139 L/tonne of cocoyam. Therefore, 10 million tonnes annual global production of cocoyam is potentially able to Research Article British Journal of Applied Science & Technology, 2(1): 1-15, 2012 2 produce 331 million gallons of ethanol (i.e. 200 million gallons gasoline equivalent) or 39.5 million cubic metres of methane which on burning would produce 179.3 x 10 MJ of energy. The mash obtained as byproduct of the processes is capable of supplying 59 calories of food energy per 100g. Conclusion: Cocoyam has very good potential as a source of ethanol and methane. Its use as a renewable source of energy for the production of biofuels is recommended and doing so poses no threat to the environment or food supply. The mash produced is an excellent feedstock for livestock. The scientific innovation and relevance of this study lies in the fact that cocoyam is a renewable produce and the fermentation and anaerobic digestion methods used are applicable across countries and regions irrespective of available degree of industrialization and climate.

International comparison CCQM-K66: Impurity analysis of methane

This key comparison was performed to demonstrate the capability of NMIs to analyse the purity of methane for use as a source gas in the preparation of standard gas mixtures. This capability is an essential requirement for the preparation of accurate standards of natural gas and some other fuels.Since it is difficult to carry out a comparison with individual samples of pure gas, the sample for this comparison was a synthetic mixture of high purity methane with selected added impurities of nitrogen, argon, carbon dioxide and ethane. These mixtures were prepared by a gas company as a batch of 10 cylinders and their homogeneity and stability were evaluated by NMIJ.The KCRVs for the four different analytes in this key comparison are based on a consensus of values reported by participants. The uncertainties in the degrees of equivalence were calculated by combining the reported uncertainties with the homogeneity of the samples and the uncertainty of the KCRV. The results submitted are generally consistent with the KCRV within the estimated uncertainties.Finally, this comparison demonstrates that the analysis of nitrogen, argon, carbon dioxide and ethane in methane at amount fractions of 1 µmol/mol to 5 µmol/mol is generally possible with an uncertainty of 5% to 10%.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Digestion of wastewater pond microalgae and potential inhibition by alum and ammoniacal-N

Algae are produced in considerable quantities in oxidation ponds, and may negatively affect receiving waters when discharged at high concentration. Thus in some instances they require removal prior to effluent discharge, which may be enhanced using flocculants such as alum. Harvested algal biomass could be anaerobically digested to methane for use as a renewable energy source, however, alum, has been reported to inhibit anaerobic digestion. Psychrophilic (20°C) anaerobic digestion experiments showed a 13% reduction in methane production with 200 g m(-3) alum in the flocculated algae, and a 40% reduction at an alum concentration of 1600 g m(-3). Elevated ammoniacal-N concentrations (785 g NH(4)(+)-N m(-3)) also inhibited algal digestion at 20°C when using an inoculum of anaerobic bacteria from a mesophylic municipal wastewater sludge digester. However, anaerobic digestion using a bacterial inoculum from a psychrophilic piggery anaerobic pond (in which typical ammoniacal-N levels range between 200 and 2000 g NH(4)(+)-N m(-3)) were unaffected by elevated digester ammoniacal-N levels and methane production actually increased slightly at higher ammoniacal-N concentrations. Thus, selecting an anaerobic bacterial inoculum that is already adapted to high ammoniacal-N levels and the digestion temperature, such as that form an anaerobic pond treating piggery wastewater, may avoid ammonia inhibition of algal digestion.

Evaluation of the effectiveness of the preliminary auto thermal conversion of methane for use in power plants

Evaluation of the effectiveness of the preliminary auto thermal conversion of methane for use in power plants

CO-free production of hydrogen via stepwise steam reforming of methane

CO-free hydrogen is produced by the reversible cyclic stepwise steam reforming of methane for use in fuel cells and other processes that are sensitive to CO poisoning. The process consists of two steps involving the decomposition of methane in a first step followed by steam gasification of the surface carbon in a second step. The ease of carbon removal in step II is strongly dependent on temperature and surface coverage of carbon. To optimize the process conditions, we have investigated this cyclic methane steam-reforming process as a function of temperature and surface coverage of carbon. These studies show that it becomes increasingly difficult to remove the surface carbon at higher temperatures and coverage. Since higher temperatures favor methane conversion and hydrogen production in step I, it is essential to delicately optimize the temperature conditions for the process. The hydrogen produced in step I of the cyclic process in the optimum range of temperature conditions (≤673 K) is CO-free (<20 ppm).The amount of H2 produced in step I varies from 1.0 to 1.3 mol/mol methane consumed. The optimum process conditions for carrying out the two-step process are temperatures of 648–673 K and a carbon surface coverage of 0.10–0.20 monolayer equivalents (MLEs).

Coal Demethanation Principles And Field Experience

Abstract INTRODUCTION A program was initiated by Noval Technologies Ltd., a subsidiary of NOVA, An Alberta Corporation, in 1976 to develop coal demethanation technology and demonstrate its econonic viability. Theoretical studies and field experiments were started in Alberta in 1977 and are continuing. In 1979, in conjunction with Petro-Canada, Naval started a test program in Nova Scotia that is to lead to commercial development. This report is a brief coverage of the theoretical background, and the results of field experience, not only of the Naval project, but also of other major demethanation projects. The relations between basic physical parameters of the coal and their impact on the demethanation process are discussed, as are the results of the field experience using vertical boreholes and the effect of the various stimulation methods used, indicating the advantages and drawbacks of each. After over five years of experience, Noval feels that coal demethanation techniques are sufficiently advanced to make a commercial project feasible. INTRODUCTION Methane has been known to exist in association with coal beds for many years. It has been known under many names, such as firedamp, methane, coal gas, etc. Traditionally, the methane in the coal was only considered when the coal was being mined and then only as a hazard. Recently, mostly as a result of the energy shortage, methane in coal has been given attention as a potential energy source. Its use as a fuel is not entirely new or innovative because, mostly in Europe, collieries have used the gas for many years. However, its use in North America in large quantities is new. Two different methods are known for extracting methane from coal. One is an underground system operating within a mine, normally referred to simply as methane drainage. It was first applied about 50 years ago in Europe. The second takes place on the ground surface and is often referred to as Virgin Coal Demethanation (VCD). The extraction technology was started in the USA approximately 12 years ago. Both methods achieve the same goal, nevertheless they go about it in entirely different ways. The major aim of the methane drainage method has traditionally been to achieve an immediate impact on the mine ventilation system by decreasing the methane concentration in the mining operations. The use of methane as a potential energy source is only a secondary concern, even though many collieries end up utilizing it. VCD, which is independent of mining operations, also reduces the methane content of the coal and makes for safer mining operations. However, being independent of a mine, it can and has been used to obtain methane for use as a fuel, irrespective of whether or not the coal will be mined. This paper will briefly discuss the principles and field experience of VCD in general and relate it to Noval's experience. The terms ?gas? and ?methane? are used interchangeably in this paper, because gas from coal is almost 100% methane. In some cases, traces of other gases are present, such as CO2, Hz, N2 and 02, but these usually constitute less than 2%.