Combination Of Methane Research Articles

An Innovative Approach for Natural Gas Liquefaction Using a Mixed-Multi-Component-Refrigerant

The natural gas liquefaction is the most expensive and energy-intensive phase in the natural gas-to-liquefied natural gas-to-natural gas chain. In addition, this region has the biggest development potential. As a result, numerous LNG production methods have been developed and are deployed at export facilities around the world. The goal of this study is to describe and assess an innovative approach for mixed-refrigerant (MR) LNG method. The authors have dubbed this technique the MR-X approach. The MR-X process was developed based on the globally proven liquefaction technology C3MR and its large-scale successor AP-X™ (which offers many benefits and flexibility), but with a novel precooling phase construct. In pre-cooling and liquefaction phases, the refrigerant is a combination of methane, nitrogen, propane, ethane, butane, and isobutane. The paper investigates the creation of the MR-X technology, as well as its modelling, energy, and exergy investigations.

A Cogeneration-Coupled energy storage system utilizing hydrogen and methane-fueled CAES and ORC with ambient temperature consideration enhanced by artificial neural Network, and Multi-Objective optimization

The increasing demand for energy in both commercial and residential sectors poses a pressing challenge, driving the ongoing quest for sustainable and virtually limitless energy resources. As nations become increasingly reliant on energy, the need to enhance energy system efficiency while curbing costs and reducing greenhouse gas emissions, particularly CO2 from fossil fuel combustion, becomes imperative. This paper presents a thermodynamics modeling, economic assessment, and optimization of a multigenerational module that utilizes compressed-air energy storing and polymer electrolyte membrane electrolysis with methane and hydrogen fuels, with a case study focused on Munich, Germany. Using EES, a system comprising of a modified organic Rankine cycle, gas turbine, PEM electrolyzer, and CAES unit was modeled. The combustion chamber was used to exploit methane and a combination of methane and hydrogen. The performance of the suggested module under these two scenarios was evaluated using multi-objective optimization to select the optimal scenario based on TOPSIS. In this study, we conducted 700 runs and obtained data on seven inputs. To derive a mathematical function from this data, we employed an Artificial Neural Network (ANN). This function was subsequently integrated into a multi-objective optimization system, allowing us to optimize the desired objectives. It was determined that Scenario 1 was the best choice for lowering the cost rate, reducing CO2 emissions, and optimizing energy round-trip effectiveness (ERTE). The highest exergy destruction rates were observed in the gas turbine, combustion chamber, and recuperator of the suggested system. The cost rates for ORC, CAES, and PEM electrolyzer were the highest according to the economic evaluation of the proposed module. Moreover, the gas turbine had the highest price. The study assessed the power demand of a building and evaluated the efficiency of the proposed power supply system. Additionally, an investigation was conducted in Munich, Germany, to examine how the system's performance is influenced by daily changes the annual variation in the environment temperature. The results revealed that the exergy destruction rates for the charging and discharging units were identified as 1706.38 kWh and 3019.31 kWh, respectively. additionally, based on the economic analysis, the total cost rate for the proposed energy production system was projected to be 68.073 USD per hour. The subsystems were ranked in the following order of costs: CAES > ORC > PEM electrolyzer. Additionally, within the specified system equipment, the gas turbine equipment exhibited the highest cost rate.

Ultra-low emission power generation utilizing chemically stabilized waste plastics pyrolysis oil in RCCI combustion concept

Emission standards in European Union, designed to reduce the environmental impact of power generation, present a significant challenge for fast-response distributed power generation systems based on internal combustion engines. Regulated emissions, such as NOx and particulate matter present a major concern due to their adverse number of environmental and health effects. Simultaneously, European Union strives towards sustainable management of plastic waste and seeks the ways for its upcycling and production of new fuels and chemicals. As an answer to the presented challenges, the present experimental study addresses the potential for use of chemically stabilized Waste Plastics Oil (WPO), a product of pyrolysis process of waste plastics in a Reactivity Controlled Compression Ignition (RCCI) combustion concept. To establish a reactivity-controlled combustion, the study uses a combination of methane (a model fuel for biomethane) and WPO to a) simultaneously reduce NOx and particulate matter emissions due to low local combustion temperatures and a high degree of charge homogenization and b) address waste and carbon footprint reduction challenges. Through experiments, influence of direct injection timing and energy shares of utilized fuels to in-cylinder thermodynamic parameters and engine emission response were evaluated in engine operating points at constant indicated mean effective pressure. Acquired results were deeply investigated and benchmarked against compression ignition (CI) and RCCI operation with conventional diesel fuel to determine potential for WPO utilization in an advanced low-temperature combustion concept. Results show that chemically stabilized WPO can be efficiently utilized in RCCI combustion concept without adaptation of injection parameters and that with suitable control parameters, ultra-low emissions of NOx and PM can be achieved with utilized fuels. For diesel/methane mix, NOx and PM emissions were reduced compared to conventional CI operation for 82.0% and 93.2%, respectively, whereas for WPO/methane mix, NOx and PM emissions were reduced for 88.7% and 97.6%, respectively, which can be ascribed to favourable chemical characteristics of WPO for the utilized combustion concept. In the least favourable operating point among those studied, indicated mean effective pressure covariance was kept below 2.5%, which is well below 5% being considered the limit for stable engine operation.

Experimental study of the characteristics of explosions generated by methane mixtures, as a function of the type of atmosphere and environmental conditions

The combination of methane – air can cause potentially explosive mixtures, which in contact with an energy source can ignite, resulting not only in the destruction of infrastructure but also in the death of people. This paper studies the ignition of different methane–air mixtures as a function of the type of mixture (methane–air, methane–nitrogen–oxygen), the kind of atmosphere (homogeneous, stratified) and the environmental conditions (initial temperature, pressure, and humidity). For this purpose, the Rock Dynamics research group of the University of Oviedo has designed and manufactured an explosive chamber, quasi-spherical in shape, instrumented with dynamic pressure sensors and accelerometers. With the results obtained after a laboratory-scale experimental campaign, pressure-concentration graphs were plotted, obtaining the explosion limits of the different mixtures. Higher oxygen concentrations (O2) have therefore been found to increase the upper explosive limit of mixtures. However, increasing methane (CH4) concentrations lead to different behaviours, depending on the type of mixture. The kind of atmosphere does not seem to affect the recorded pressures, as they are similar for homogeneous and stratified atmospheres. Finally, initial pressures above atmospheric lead to higher detonation pressures, while a high initial humidity content decreases the likelihood of explosion.

Determination of the explosion parameters of methane-air mixtures as function of the ignition source and the volume and shape of the explosion chambers

The combination of methane - air can cause potentially explosive mixtures, which in contact with an energy source can ignite, resulting not only in the destruction of infrastructure but also in the death of people. The aim of this paper is to study the ignition of methane - air mixtures with different concentration of methane, as a function of the ignition sources used and the volume and geometry of the explosion chamber. For this purpose, the ‘Dynamic Behaviour of the Rock mass (DinRock)' research group of the University of Oviedo has designed and manufactured 3 explosion chambers of different sizes and shapes, instrumented with dynamic pressure sensors and accelerometers. In addition, the ignition process has been recorded with a high-speed camera. With the results obtained after a laboratory-scale experimental campaign, the maximum pressure reached, the pressure gradients and the acceleration of the pressure waves were analysed. Thus, it has been determined that the maximum pressure reached is independent of the ignition source used and the chamber volume, but not of the chamber geometry. Methane (CH4) concentrations between 8.0 and 9.0% generated the highest pressures between 1.5 and 2.5 MPa. A correlation between peak acceleration and peak pressure has also been established allowing to identify whether a deflagration or a detonation has occurred.

Theoretical Prediction of CHn Crystal Structures under High Pressures

CHn is the precursor unit for graphene synthesis. We have theoretically predicated a series of CHn structures with n = 1, 2, 4, 6, 8, 10, and 12 at elevated pressures (ambient pressure, 50, 100, 200, 300, 350, and 400 GPa) using evolutionary algorithms. The predicted CH and CH2 structures are graphane-type and polyethylene over the whole considered pressure range, respectively. The molecular crystalline methane is predicted for the stoichiometry of CH4. The combination of methane and H2 for CH6, CH8, CH10, and CH12 up to 300 GPa are obtained. At 400 GPa, the mixture of polymer and H2 for CH6, CH10, and CH12 comes into play. From the computed enthalpy, higher pressure and more hydrogen concentration contributed to the decomposition (to carbon and H2) of CHn systems. The total density of states for these CHn structures show that only the CH12 phase is metallic above 300 GPa. The rotational properties are traced in H2 and the CHn structures. The CH4 rotation is more sensitive to the pressure. The H2 units are nearly freely rotational. Other structures of CHn, including fcc-type and experimentally known structures, are not competitive with the structures predicted by evolutionary algorithms under high pressure region. Our results suggest that the CHn (n > 4) system is a potential candidate for hydrogen storage where H2 could be released by controlling the pressure.

Microbial Communities Associated with Bentic Invertebrates of Lake Baikal.

The first results of a study into the microbiomes of benthic invertebrates found in sites with seeps (containing methane, oil, or a combination of methane and mud) and an underwater low-temperature vent of Lake Baikal are presented. Microorganisms were detected in the intestine of an oligochaete from the cold methane seep using microscopy. Analysis of 16S rRNA gene libraries revealed that the highest diversity of microorganisms was found in the nematode microbiomes where the members of 11 phyla were identified. Some of the detected prokaryotes are methanogens, nitrifiers, and nitrogen fixators, while some are involved in the sulfur cycle. Methanotrophs were detected in the microbiomes of oligochaetes and chironomids. The microbiomes of nematodes, chironomids, and bathynellids are composed of members of the Bacteroidetes and Firmicutes phyla, which are related to the symbiotic bacteria found in insects and animals from other ecotopes. Microorganisms typically found in the water and sediments of Lake Baikal were also detected in the invertebrates microbiomes.

Mitigation of harmful exhaust pollutants of DI diesel engine using emulsified fuel and hythane gas in a dual-fuel mode

ABSTRACT The current investigation aims to explore the effects of hythane gas and water in diesel emulsion (WiDE) in a dual-fuel mode. Generally, the Wide gives a drastic reduction of NOX emissions due to the vaporization of water particles in the combustion chamber results in lower combustion temperature. On the other side, the WiDE causes a decline in thermal efficiency due to its lower low heating value. The combination of methane and hydrogen (hythane) gas samples has been used as secondary fuel for getting the promising reduction of exhaust emissions without reduction of thermal efficiency of the engine. Initially, experiments are conducted with Wide fuel with water concentrations of 5%, 10%, and 15% and the rest of the diesel fuel by volume. The physicochemical properties of the prepared fuels were measured using ASTM standards. The base test results revealed that the WiDE10 is shown higher brake thermal efficiency (BTE) and lower exhaust emissions when contrasted with the other emulsified fuel samples. Later, the Wide10 emulsion fuel is further examined as the primary direct fuel along with hythane as a secondary fuel. The hythane fuel is prepared in two samples like hythane10 and hythane20 by means of methane and hydrogen percentage on an energy basis. The hythane fuel samples are supplied to the diesel engine at two flow rates like 4 liters per minute (lpm) and 5lpm. The maximum BTE was found of the WiDE10 with hythane20 at 5 lpm is 28.02% at full of load condition which is 5.69% of the higher when contrasted with the WiDE10 operation in a single fuel mode. The maximum in-cylinder pressure is found for the WiDE10 with hythane20 at a flow rate of 5lpm because of the higher hydrogen content shows the higher the flame speed results in improved combustion phenomena.

Aerobic oxidation of methane to formaldehyde mediated by crystal-O over gold modified tungsten trioxide via photocatalysis

General indirect transformation of methane into formaldehyde is based on methanol as intermediate yet leading to low selectivity. Herein, we report a direct photocatalytic conversion of methane to formaldehyde over gold modified cuboid-shaped tungsten trioxide with exposed (002), (020) and (200) facets containing crystal-O at room temperature (25 °C). Under light irradiation, high spin state crystal-O− ion as a hole can active CH bond in methane and subsequently be consumed to form formaldehyde, then renovated by the addition of oxygen. Isotopic 13CH4 and 18O2 tests reveal that formaldehyde indeed stems from the combination of methane and crystal-O on the exposed (002), (020) and (200) facets. Besides, metallic gold deposited on the surface of cuboid-shaped tungsten trioxide can extract the photoexcited electrons and further enhance the formation of crystal-O− ions. The productivity of formaldehyde over optimized catalyst can reach 7202 μmol g-1 with approximate 100 % selectivity within 24 h reaction time.

Shallow Seafloor Gas emissions Near Heard and McDonald Islands on the Kerguelen Plateau, Southern Indian Ocean

AbstractBubble emission mechanisms from submerged large igneous provinces remains enigmatic. The Kerguelen Plateau, a large igneous province in the southern Indian Ocean, has a long sustained history of active volcanism and glacial/interglacial cycles of sedimentation, both of which may cause seafloor bubble production. We present the results of hydroacoustic flare observations around the underexplored volcanically active Heard Island and McDonald Islands on the Central Kerguelen Plateau. Flares were observed with a split‐beam echosounder and characterized using multifrequency decibel differencing. Deep‐tow camera footage, water properties, water column δ3He, subbottom profile, and sediment δ13C and δ34S data were analyzed to consider flare mechanisms. Excess δ3He near McDonald Islands seeps, indicating mantle‐derived input, suggests proximal hydrothermal activity; McDonald Islands flares may thus indicate CO2, methane, and other minor gas bubbles associated with shallow diffuse hydrothermal venting. The Heard Island seep environment, with subbottom acoustic blanking in thick sediment, muted 3He signal, and δ13C and δ34S fractionation factors, suggest that Heard Island seeps may either be methane gas (possibly both shallow biogenic methane and deeper‐sourced thermogenic methane related to geothermal heat from onshore volcanism) or a combination of methane and CO2, such as seen in sediment‐hosted geothermal systems. These data provide the first evidence of submarine gas escape on the Central Kerguelen Plateau and expand our understanding of seafloor processes and carbon cycling in the data‐poor southern Indian Ocean. Extensive sedimentation of the Kerguelen Plateau and additional zones of submarine volcanic activity mean additional seeps or vents may lie outside the small survey area proximal to the islands.

Mechanics of Foamy Oil during Methane-Based Cyclic Solvent Injection Process for Enhanced Heavy Oil Recovery: A Comprehensive Review

Summary Foamy oil flow is a commonly encountered drive mechanism in the primary production (depletion of naturally methane-saturated heavy oil) and secondary stage (cyclic gas—mostly methane—injection after primary production). In the former, among other important parameters, pressure depletion rate has been reported to be the most crucial parameter to control the process. In the latter, type and amount of the gas (also described as “solvent”) and application conditions such as soaking time durations and depletion rates are critical. The cornerstone of the foamy oil behavior relies on its stability, which depends on parameters such as oil viscosity, temperature, dissolved gas ratio, pressure decline rate, and dissolved gas (solvent) composition. Although the process has been investigated and analyzed for different parameters in the literature, the optimal conditions for an efficient process (mainly foamy oil stability) has not been thoroughly understood, especially for the secondary recovery conditions (cyclic solvent injection, CSI). In this paper, internal and external gas drive mechanisms for foamy oil performance are reviewed in detail. The optimal conditions of the applications were compiled and listed for different primary production and secondary recovery stages. Combination of methane with other gases as a CSI practice was also discussed to accelerate the process and reduce cost in an effort to improve efficiency. It is reported that combining methane injection with air as a secondary recovery method can save up to 51% of solvent gas.

METHOD OF NATURAL HYDRATE METHANE PRODUCTION WITH SIMULTANEOUS CARBON ACID SEQUESTION

Background Methane hydrate is a combination of methane with water, resistant to low temperatures and high pressure, outwardly resembles compressed snow. According to investigations, the reserves of methane hydrates are considered the largest reserves of natural methane, exceeding the world's oil reserves. Since methane is also a valuable natural energy source, timely development of its reserves is important for the economy and ecology. At present, a search is underway for a promising method for extracting methane from its hydrates. Recent research into the exploitation of this energy resource is related to CO2 sequestration, so this energy source can be obtained through CO2 sequestration, which will help to reduce the threat of global warming. However, be aware that the threat of global warming in this case is itself produced methane which is a greenhouse gas, therefore, must strike a balance in this process. Aims and Objectives Consideration of a new version of the method of extraction of methane from natural hydrates with simultaneous sequestration of carbon dioxide. Results In this paper, we propose a promising method for extracting hydrated methane that allows increasing the rate and depth of dissociation of methane hydrate with a sufficiently high degree of substitution of methane hydrate for carbon dioxide hydrate in the reservoir.

The effect of methane and odd-chain fatty acids on 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) synthesis by a Methylosinus-dominated mixed culture

A methanotrophic community was enriched in a semi-continuous reactor under non-aseptic conditions with methane and ammonia as carbon and nitrogen source. After a year of operation, Methylosinus sp., accounted for 80% relative abundance of the total sequences identified from potential polyhydroxyalkanoates (PHAs) producers, dominated the methane-fed enrichment. Prior to induction of PHA accumulation, cells harvested from the parent reactor contained low level of PHA at 4.0 ± 0.3 wt%. The cells were later incubated in the absence of ammonia with various combinations of methane, propionic acid, and valeric acid to induce biosynthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Previous studies reported that methanotrophic utilization of odd-chain fatty acids for the production of PHAs requires reducing power from methane oxidation. However, our findings demonstrated that the PHB-containing methanotrophic enrichment does not require methane availability to generate 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV)—when odd-chain fatty acids are presented. The enrichment yielded up to 14 wt% PHA with various mole fractions of 3HV monomer depending on the availability of methane and odd-fatty acids. Overall, the addition of valeric acid resulted in a higher PHA content and a higher 3HV fraction. The highest 3HV fraction (up to 65 mol%) was obtained from the methane–valeric acid experiment, which is higher than those previously reported for PHA-producing methanotrophic mixed microbial cultures.

Titanium(IV) isopropoxide as a source of titanium and oxygen atoms in carbon based coatings deposited by Radio Frequency Plasma Enhanced Chemical Vapour Deposition method

This paper presents properties of TiOx-DLC (titanium oxides incorporated diamond like carbon) coatings deposited by RF PECVD (Radio Frequency Plasma Enhanced Chemical Vapour Deposition) method using combination of methane (CH4) and titanium(IV) isopropoxide (Ti[OCH(CH3)2]4) atmospheres. The obtained results show that the deposition process of TiOx-DLC coatings is strongly affected by the concentration of TTIP (titanium (IV) isopropoxide) precursor in working atmosphere. The proposed technology allows to obtain TiOx-DLC coatings with Ti concentration up to 10 at.%. Higher concentrations of Ti in the coating (5 and 10 at.%) result in twice the concentration of oxygen. As the results of the investigation it was noticed, stable TiOx-DLC coatings showing acceptable hardness and residual stress, as well as good optical properties contain up to 1.5 at.% of Ti and can be deposited at 400 V of the negative self-bias using 0.05 of TTIP partial pressure ratio.

Thermophilic production of poly(3-hydroxybutyrate-co-3-hydrovalerate) by a mixed methane-utilizing culture

The production of polyhydroxyalkanoates (PHAs) from methane is limited to mesophiles and thus suffers from high energy requirements for cooling. To address this issue, the use of thermophilic processes is gaining interest, as this strategy may deliver improved economic feasibility for PHA production. This study reports the first thermophilic PHA-producing culture grown on methane at 55 °C in fill-and-draw batch reactors. Harvested cells were incubated with various combinations of methane, propionic acid and valeric acid to assess their capacity for the synthesis of poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Only PHB was produced when fed with methane alone. The addition of odd-carbon-number fatty acids resulted in higher PHA content with 3 HV fractions in the range of 15–99 mol%, depending on the types of fatty acids added. Acetic acid addition enhanced the synthesis of 3HB monomer, but not of 3 HV. On increasing the temperature to 58 °C, PHA productivity was not significantly affected.

Deposition behavior and tribological properties of diamond-like carbon coatings on stainless steels via chemical vapor deposition

A systematic investigation was carried out to observe the deposition rate of a diamond-like carbon (DLC) coating on two stainless steel substrates by chemical vapor deposition (CVD). The objective of this research is to study the deposition behavior of the DLC coating and its tribological properties in different combinations of methane (CH4) and nitrogen, which were used as precursor gases. The results reveal that the deposition rate increases with increasing CH4 content up to 50vol%. The hardness of the DLC-deposited layer also increases while the friction coefficient decreases with increasing CH4 gas content up to 50% in the precursor gas mixture.

Tribological and corrosive investigations of perfluoro and alkylphosphonic self-assembled monolayers on Ti incorporated carbon coatings

Abstract This paper presents tribological and corrosion properties of perfluoro and alkylphosphonic self-assembled monolayers formed on Ti incorporated carbon coatings. The Ti-DLC incorporated coatings were deposited on Ti6Al4V substrates by Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF PECVD) method using combination of methane (CH 4 ) and titanium (IV) isopropoxide (Ti [OCH(CH 3 ) 2 ] 4 ) atmospheres. The obtained coatings were subsequently modified by perfluoro and alkylphosphonic self-assembled layers having hydrocarbon or perfluorocarbon chains (DP and PFDP). Presented results show that application of these compounds on the top of Ti-DLC coatings significantly improves their tribological properties. After 1000 m of ball-on-disc test the DP- and PFDP- modified coatings presented low coefficient of friction, showing particularly more stable and lower value in case of PFDP while the unmodified coating was worn out already after 160 m of the test under the same conditions. The corrosion tests show varied results for both modifiers. In the case of PFDP an increased reactivity of the coating is observed, whereas for DP the results prove the anti-corrosive effect of this self-assembled layer.

Demonstration of a Biogas Methanation Combined with Membrane Based Gas Upgrading in a Promising power-to-gas Concept

The further development of photovoltaic and wind power as renewable energies with their production rate fluctuations both on short- and medium-time-scale result in the necessity of smarter grids and higher energy storage capacities. One very prominent and promising technology for meeting this future electric energy storage demand is the concept of power-to-gas. Here, the excess electric energy is converted to hydrogen using alkaline or PEM electrolysis. Most concepts incorporate an immediate subsequent conversion to methane using a local carbon dioxide source and a process of thermo-catalytic or biological methanation. After a final gas upgrading mainly comprising the separation of H2, CO2 and H2O the produced SNG can be fed to the natural gas grid owning a huge potential for energy storage and distribution. The current work presents the joint research efforts undertaken by the authors in the field of power-to-gas processes. A process chain consisting of a coupled hydrogen dark fermentation and a biogas fermentation, a thermo-catalytic methanation step and product gas upgrading applying membrane-based gas-permeation is developed and demonstrated on laboratory scale. The described process chain has been demonstrated on a scale of roughly 0.5 m³(STP)/h and experimental results will be presented. Special emphasize is laid on the analysis of the methanation performance considering the changing content of the mixed raw biogas. It is shown that the combination of methanation with membrane-base gas separation technology provides significant advantages for process integration.

Pyrolusite–CO reduction kinetics

Pyrolusite is an inexpensive and nontoxic manganese ore with exceptional oxygen transfer capacity that makes it a potential candidate for chemical looping combustion. We evaluate the oxygen transfer capacity and kinetics of pyrolusite, an inexpensive and nontoxic manganese ore. We reduced it with carbon monoxide and a combination of carbon monoxide, methane and hydrogen. At 960°C, carbon monoxide and hydrogen reduce the calcined pyrolusite 86% more than does a pure CO stream. We derived a mechanistic kinetic model based on the effluent species concentration during reduction with a combination of methane, carbon monoxide and hydrogen from 810°C to 960°C. The direct reduction of surface oxygen sites by carbon monoxide, in equilibrium with the reverse CO2 reoxidation, in addition to the reoxidation of the surface by oxygen atoms from the bulk of the lattice, explains more than 95% of the variance of the data. We estimated surface parameters by comparing the carbon monoxide and helium washout curves and by analyzing the initial response to a step change in the inlet concentration. Adsorbed CO increased with temperature, up to 910°C, where it peaked at 55μmolm−2, corresponding to a 70% covered surface. The estimated oxygen surface site density followed an asymptote at 40μmolm−2, in agreement with measured values.

An overview of physico-chemical mechanisms of biogas production by microbial communities: a step towards sustainable waste management.

Biogas is a combination of methane, CO2, nitrogen, H2S and traces of few other gases. Almost any organic waste can be biologically transformed into biogas and other energy-rich organic compounds through the process of anaerobic digestion (AD) and thus helping in sustainable waste management. Although microbes are involved in each step of AD, knowledge about those microbial consortia is limited due to the lack of phylogenetic and metabolic data of predominantly unculturable microorganisms. However, culture-independent methods like PCR-based ribotyping has been successfully employed to get information about the microbial consortia involved in AD. Microbes identified have been found to belong mainly to the bacterial phyla of Proteobacteria, Chloroflexi, Firmicutes and Bacteroidetes. Among the archaeal population, the majority have been found to be methanogens (mainly unculturable), the remaining being thermophilic microbes. Thus, the AD process as a whole could be controlled by regulating the microbial consortia involved in it. Optimization in the feedstock, pH, temperature and other physical parameters would be beneficial for the microbial growth and viability and thus helpful for biogas production in AD. Besides, the biogas production is also dependent upon the activity of several key genes, ion-specific transporters and enzymes, like genes coding for methyl-CoM reductase, formylmethanofuran transferase, formate dehydrogenase present in the microbes. Fishing for these high-efficiency genes will ultimately increase the biogas production and sustain the production plant.