Biogas Research Articles

Multi-objective optimization of straw-based bio-natural gas supply chains considering cost, CO2 emission, and safety

Bio-natural gas (BNG) has received recent interest as a renewable alternative to natural gas (NG). BNG supply chains (BSC), including production, transportation, and utilization, are compatible and can overlap with existing NG infrastructure. The goal is to develop a set of models that achieve the various trade-offs between economic, environmental and safety risks by combining life cycle assessment (LCA), mixed-integer linear programming (MILP) and fuzzy optimization, expanding the utilization of BSC while quantifying the risk of the whole process, so as to improve the safety awareness of the project operation. BNG technologies were considered: anaerobic digestion (AD), gasification, and syngas methanation. This model can analyze the changes in the different objectives of each module and the distribution of biomass mass flow by comparing different straw-based harvesting rates. Results indicate that AD technology possesses the lowest economic cost, and BNG as transportation fuel will generate the most benefits. The unit cost of BNG for different technologies ranges from 0.36 to 0.67 $/m³，the emission reduction is from 5.18 kg/m³ to 10.28 kg/m³，and the maximum safety risk value is 1.96. The proposed model was applied to a case study in China to illustrate the optimization of a regional straw-based BSC. The results illustrate how BNG supply chains can be systematically planned as part of an integrated decarbonization policy while mitigating safety risks that may occur from handling this fuel.

Point Source Capture of Methane Using Ionic Liquids in Packed Bed Absorbers/Strippers: Experimental and Modelling

Fugitive methane emissions from the mining industry, particularly so-called ventilation air methane (VAM) emissions, are considered among the largest sources of greenhouse gas (GHG) emissions. VAM emissions not only contribute to the global warming but also pose a significant hazard to mining safety due to the risk of accidental fires and explosions. This research presents a novel approach that investigates the capture of CH4 in a controlled environment using 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [BMIM][TF2N] ionic liquid (IL), which is an environmentally friendly solvent. The experimental and modelling results confirm that CH4 absorption in [BMIM][TF2N], in a packed column, can be a promising technique for capturing CH4 from point sources, particularly the outlet streams of ventilation shafts in underground coal mines, which typically accounts for <1% v/v of the flow. This study assessed the effectiveness of CH4 removal in a packed bed column by testing various factors such as absorption temperature, liquid and gas flow rates, flow pattern, packing size, desorption temperature, and desorption pressure. According to the optimisation results, the following parameters can be used to achieve a CH4 removal efficiency of 23.8%: a gas flow rate of 0.1 L/min, a liquid flow rate of 0.5 L/min, a packing diameter of 6 mm, and absorption and desorption temperatures of 303 K and 403.15 K, respectively. Additionally, the experimental results indicated that ILs could concentrate CH4 in the simulated VAM stream by approximately 4 fold. It is important to note that the efficiency of CH4 removal was determined to be 3.5-fold higher compared to that of N2. Consequently, even though the VAM stream primarily contains N2, the IL used in the same stream shows a notably superior capacity for removing CH4 compared to N2. Furthermore, CH4 absorption with [BMIM][TF2N] is based on physical interactions, leading to reduced energy requirements for regeneration. These findings validate the method’s effectiveness in mitigating CH4 emissions within the mining sector and enabling the concentration of VAM through a secure and energy-efficient procedure.

Women's empowerment, modern energy, and demand for maternal health services in Benin.

One of the major concerns for developing countries is improving the use of health services by the general population, and in particular, maternal and child health services. This concern reflects the Sustainable Development Goals 3, which aim to ensure the health and well-being of all by improving reproductive health, and especially maternal and child health. This study analyses the extent to which modern energies improve women's empowerment and the demand for maternal health services in a low income country. The empirical estimations were based on the 2017 Benin Demographic Health Survey data. We adopted the trivariate recursive probit modelling to find out the extent to which modern energies improve women's empowerment and the demand for maternal health services. The results revealed that the demand for maternal health services was significantly and positively associated with women's empowerment. Notably, being an empowered woman (social independence and decision-making) increases the chance of completing antenatal care visits. We further highlighted the importance of women's wealth in accessing maternal health services. To address maternal mortality in sub-Saharan African countries, policymakers should improve women's social independence, decision making power and attitude to violence by promoting access to modern energies such as electricity, Liquefied petroleum gas, and bio gas.

Addressing Methane Venting: Strategies and Implications on the Environment

Industrial processes, including oil and gas production, landfill operations, and agriculture, emit methane, a potent greenhouse gas. This article examined methane emissions in Rivers State's Soku, Agbada, and Oyigbo oil and gas extraction communities. The net methane emissions(mg/l) for facilities A, B, and C are 0.90, 0.28, and 1.03, respectively. The corresponding temperature rise for the host communities over the same period were 1.87 oC, 0.37 oC, and 1.16 oC, respectively. All three sites have near-neutral unstable methane dispersion using Monin-Obukhov length. This article examined new methane venting mitigation technologies and their effects on bioenergy and environmental engineering. The study analyzed existing methane venting trends in several Rivers State oil production sites and their effects on local temperature and the environment, emphasizing the necessity for adequate mitigation. This paper also examined new methane capture, use, and sequestration technologies. The article also examines methane mitigation and bioenergy industry synergies, stressing co-benefit strategies that improve sustainability and economic feasibility. Methane mitigation strategies in Rivers State increase energy efficiency, carbon footprint, and air quality, according to the paper. This study helps reduce methane emissions by providing possible alternatives and their effects on bioenergy development and environmental stewardship. Interdisciplinarity and innovation are encouraged to accelerate sustainable and resilient development.

CO2 Capture and Enhanced Hydrogen Production Enabled by Low-Temperature Separation of PSA Tail Gas: A Detailed Exergy Analysis

Hydrogen from natural gas reforming can be produced efficiently with a high CO2 capture rate. This can be achieved through oxygen-blown autothermal reforming as the core technology, combined with pressure-swing adsorption for hydrogen purification and refrigeration-based tail gas separation for CO2 capture and recirculation of residual hydrogen, carbon monoxide, and methane. The low-temperature tail gas separation section is presented in detail. The main objective of the paper is to study and quantify the exergy efficiency of this separation process in detail. To achieve this, a detailed exergy analysis is conducted. The irreversibilities in 42 different process components are quantified. In order to provide transparent verification of the consistency of exergy calculations, the total irreversibility rate is calculated by two independent approaches: Through the bottom-up approach, all individual irreversibilities are added to obtain the total irreversibility rate. Through the top-down approach, the total irreversibility rate is calculated solely by the exergy flows crossing the control volume boundaries. The consistency is verified as the comparison of results obtained by the two methods shows a relative deviation of 4·10−7. The exergy efficiency of the CO2 capture process is calculated, based on two different definitions. Both methods give a baseline exergy efficiency of 58.38%, which indicates a high degree of exergy utilisation in the process.

Exceptional capture of methane at low pressure by an iron-based metal-organic framework.

The selective capture of methane (CH4) at low concentrations and its separation from N2 are extremely challenging owing to the weak host-guest interactions between CH4 molecules and any sorbent material. Here, we report the exceptional adsorption of CH4 at low pressure and the efficient separation of CH4/N2 by MFM-300(Fe). MFM-300(Fe) shows a very high uptake for CH4 of 0.85 mmol g-1 at 1 mbar and 298 K and a record CH4/N2 selectivity of 45 for porous solids, representing a new benchmark for CH4 capture and CH4/N2 separation. The excellent separation of CH4/N2 by MFM-300(Fe) has been confirmed by dynamic breakthrough experiments. In situ neutron powder diffraction, and solid-state nuclear magnetic resonance and diffuse reflectance infrared Fourier transform spectroscopies, coupled with modelling, reveal a unique and strong binding of CH4 molecules involving Fe-OH⋯CH4 and C⋯phenyl ring interactions within the pores of MFM-300(Fe), thus promoting the exceptional adsorption of CH4 at low pressure.

Kajian Teknis Dan Finansial Interkoneksi Pembangkit Listrik Tenaga Biogas Dari Palm Oil Mill Effluent (POME) Pada Sistem 20 KV Di Kabupaten Musi Rawas

Using renewable energy is one way to reduce global warming. Minister of Energy and Mineral Resources Regulation No. 21 of 2016 concerning Purchase of Electricity and Biogas Power. The government has supported efforts to develop electrical energy from biogas. PT Evans Lestari is an oil palm plantation company operating in Mura with a plantation area of 9,220 ha and a mill of 60 tons/hour. In order to fulfill PLN's requirements to offer electricity supply, it is necessary to carry out a technical assessment of the connection and an economic analysis. The connection of the EBT PLT to PLN's 20 kV distribution system has been regulated in Directors' Decree No. 0357.K/DIR/2014. The benefits obtained from using DG include reducing power losses and improving the voltage profile of the distribution system. Among the types of DG that are commonly used, one of them is the Bio Gas Power Plant (PTBG) fueled by liquid palm oil waste.

Increase in energy efficiency of tunnel composting by bio leaching and biogas production

Bio waste treatment can be done by composting or by digestion. Both ways of treatment have their advantages and disadvantages. The increase in energy efficiency of tunnel composting approached by a bio leaching system and bio gas production is one part of the EnBV research project. The reduction of organic matter by bio leaching and the enrichment of carbons in the leachate water can be used for increasing the energy efficiency.

Perancangan Media Informasi Berbasis Video Dokumenter Pengenalan Produk Bio Gas Kelompok Tani Simantri Sandakan, Sulangai, Petang

The province of Bali, Indonesia, as a tropical destination with abundant natural resources, exhibits a serious focus on the agriculture and livestock sectors. The Simantri program, as a local government innovation, aims to accelerate the adoption of agricultural technology in rural communities. Bio gas, as a renewable energy alternative, emerges as a crucial solution amid the challenges posed by unsustainable fossil fuels. The Simantri Farmers Group in Br. Sandakan, Sulangai Village, faces challenges in introducing their bio gas products to the community. In the Community Service activity, a documentary video was created as an effective informational medium, successfully introducing, enhancing understanding, and raising awareness about the use of bio gas among the community. The video not only promoted the product but also strengthened the role of Simantri in village development and tourism potential. The success of this activity reaffirms that utilizing video-based informational media is an effective step in introducing innovations, enhancing understanding, and supporting the well-being of the local community.

Thermodynamic and economic analysis of a novel design for combined waste heat recovery of biogas power generation and silicon production

A novel hybrid system based on a combination of a gas turbine cycle, a supercritical carbon dioxide cycle, and an organic Rankine cycle is devised for power generation. Based on the joint layout proposed in this study, the collaborative and efficient utilization of biogas from anaerobic digestion and flue gas from industrial silicon production can be realized. The clean biogas harvested from anaerobic digestion is exploited by a gas turbine, and the resulting hot exhaust gas is then combined with the flue gas from industrial silicon production to power the supercritical carbon dioxide cycle. Addition, the organic Rankine cycle is added as the bottom cycle in the supercritical carbon dioxide cycle to further improve the waste heat utilization efficiency. Energy, exergy, and economic analysis are performed to assess the system's performance and feasibility, the energy and exergy efficiencies are calculated as 43.61 % and 51.07 %, only 4.09 years are needed to recoup the initial investment of the design, and the net present value is as high as 136,864.14 k$.

Optimized scheduling of virtual plants with bio gas and electrohydric alcohol based on stepped carbon transactions

In order to reduce carbon emissions and promote clean energy development and utilization, a virtual plant optimization scheduling strategy for bio gas coupled to methanol synthesis units based on a stepped carbon transaction mechanism is proposed. This strategy is based on the transportation cost of hydrogen energy storage and the reality that methanol is widely used in the industry, to construct a second-order variable pressure adsorptive bio gas and electro alcohols linked production model, to extract high purity natural gas and CO2, and to couple the methanol synthesis unit with the bio gas equipment, while introducing a stepped carbon trading mechanism to realize CO2 recycling and wind with the lowest running cost in a virtual power plant Efficient dissipation of photogenerated electrical energy. Finally, by setting up different scenarios and conducting computational validation, the analytical results confirm that the proposed model strategy can meet the demands of low carbon and economy in virtual power plants.

Anaerobic biodigester as a community-based food waste processor (case study: Canteen area of PT PLN Nusantara Power UP Muara Karang)

In 2022, DKI Jakarta disposed of ± 8,000 tons/day of waste to the Integrated Waste Processing Site (TPST) Bantar Gebang. Among them, 3,761.90 tons/day of organic waste were generated from domestic activities. Considering the amount of organic waste, the potential to convert it into biogas through anaerobic biodigester was feasible. As the organic waste decomposes, it produces methane (CH4) gas, which holds value as a renewable alternative energy source. Processing food waste into biogas is not only perceived as an effective way to reduce CH4 hazards but also provides economic benefits for the community. PT PLN Nusantara Power UP Muara Karang, located in Pluit - North Jakarta, attempted to make a breakthrough in waste management, especially in the Pluit Sub-district, through a methane capture and processing facility. Employing quantitative methods with primary data, this research was conducted from May to August 2023 and focused on the canteen area whose tenants came from the Pluit neighborhood. The anaerobic biodigester facility has a design capacity of up to 5 m3 or 800 kg of food waste. In its initial operation (May to August 2023), the food waste processed 363.5 kg and produced 40.7 m3 of methane gas, or 1.4009 GJ, and was used by canteen tenants for their daily operations. Annually, based on its initial condition, the activity conducted in this research can reduce greenhouse gases by 690 kg CO2e and provide economic benefits of Rp 16,000,000.

Progress and industrialization development trends of the anaerobic digestion technologies for bio-natural gas

Progress and industrialization development trends of the anaerobic digestion technologies for bio-natural gas

EFFECTIVE DEVELOPMENT OF INDUSTRY THROUGH USE OF NEW TOOLS AND MECHANISMS

The development of the industry stimulates the functioning of environmental projects related to agriculture, renewable energy sources, and environmentally friendly industry. Improving the system of “green” lending in banks contributes to the development of the private sector on new terms, which implies maximum preservation of natural resources and receiving more profit than from traditional projects. When issuing loans for the development of sustainable entrepreneurship, the banking sector seeks to support clients in the transition to sustainable solutions, since the conservation of resources and the creation of energy-saving technologies determine the future capabilities of the state. Green loans are an effective and significant tool for the development of sustainable entrepreneurship in the industry. And the conditions and procedure for issuing them are the mechanism through which the industry develops. Green loans can also be issued for projects of large clients in support of the industry, which meets the requirements of the SEB system. By choosing a green loan to finance a project, the enterprise becomes part of a sustainable management system. The most relevant areas for obtaining "green" loans are: renewable energy (solar, wind, tidal energy, bioenergy; energy efficiency - in relation to district heating or cooling; clean transport - non-fossil fuels or hybrid transport solutions; waste management - energy from waste and methane capture projects, as well as projects to reduce waste through process improvement; emission reduction - reduction of emissions of particulate matter, heavy metals and dioxins through physical, chemical, mechanical means; sustainable forestry - forestry projects with a forest management certificate or equivalent scheme certification; water and wastewater treatment – drinking water production, wastewater treatment, water resources management.

The Impact of Atmospheric Pressure Changes on Methane Emission from Goafs to Coal Mine Workings

Increased effectiveness of methane drainage from sealed post-mining goaves in hard coal mines contributes to reduced methane emission from goaves into the mine ventilation system. This paper focuses on issues concerning the assessment of the additional amount of methane released from the goaf into mine workings during periods of atmospheric pressure drops, which can be captured with a methane drainage system. Thanks to the solutions presented in the paper, it is possible to control the efficiency of the goaf drainage system, which in turn leads to the reduction of methane emission from the mine ventilation air into Earth’s atmosphere. These solutions are of great added value for both the environment and coal mines as they reduce the costs arising from greenhouse gas emissions that are incurred by mining companies, increasing the efficiency of methane capture and its use in gas engines or district heating systems. The paper uses relationships relating to the influence of atmospheric pressure changes on the process of gas release from the goaf according to the hysteresis loop of methane release during atmospheric pressure changes, which was developed based on conducted research. The analysis and conclusions presented in this paper may facilitate the development of strategies aimed at reducing methane emissions from a mine’s ventilated air into Earth’s atmosphere.

Unravelling the effect of H2O and O2 in flue gas on Integrated carbon capture and dry reforming of methane

Integrated carbon capture and utilization by dry reforming of methane (ICCU-DRM) is an efficient technology for concentrating and utilizing diluted CO2 from flue gas. Significant progresses have been made in developing efficient adsorption-catalytic dual functional materials (DFMs) for ICCU-DRM. However, reaction characteristics are mainly obtained under the idealized flue gas, disregarding the presence of H2O and O2 in industrial flue gases, which may lead to notable distinctions on ICCU-DRM reactions. Herein, reaction characteristics of ICCU-DRM with the presence of single steam or O2 and their coexistence in flue gas are comprehensively investigated using a Ni-CaO DFM. Results show that steam promotes the cladding effect of CaO on catalyst, resulting in the delay of in-situ DRM. Meanwhile, the oxidation of DFM by O2 deactivates the catalyst in DFM, and the increase of O2 concentration in flue gas leads to an aggravated deactivation. With the presence of both steam and O2 in the flue gas, the delayed in-situ DRM is intensified, and O2 dominates the negative effect.

Design and techno-economic analysis of an off-grid integrated PV-biogas system with a constant temperature digester for a cost-effective rural application

This study addresses the issue of fluctuating output in cow dung-based biogas (BG) production due to temperature dependence. A thermal model is proposed and implemented in an area with abandoned BG resources, utilizing typical meteorological year (TMY) data. The model aims for constant BG output by maintaining digester temperature at 39 °C throughout the year. It is found that integrating heating with a 3100 CUM cow dung-based biogas digester (BD) increase the energy production capacity from 2.25 GWh/year to 3 GWh/year. Subsequently, three different cases are studied: standalone PV, PV-BG system, and PV-BG system with the heating arrangement, and they are scheduled using the area's TMY data, according to a strategy that can fulfil highly dynamic load curves with 690 kW peak and 264 kW average demand, as reported by the Government of India, with zero loss of power supply probability (LPSP). In the proposed case, the integration of heating reduced the PV and energy storage system (ESS) sizes by 65 % and 52 %, respectively. The current system imposes a COE of INR 2.1/kWh, which is 70 % cheap than grid electricity in the surrounding areas, with the help of proper resource estimation utilizing TMY data, integration of heating, and compressed biogas (CBG) production with energy.

Microwave-Assisted hydrothermal carbonization and characterization of Amazonian biomass as an activated carbon for methane adsorption

Activated carbons were prepared from Amazonian biomass by means of microwave-assisted hydrothermal carbonization and activated with CO2. These materials were investigated as methane adsorption sorbents. The prepared samples were submitted to textural investigations and comprehensive characterizations using scanning electron microscopy, Transmission electron microscopy, energy dispersive X-ray diffraction, Raman and FTIR spectroscopy. Values of specific surface areas and pore volume ranged from 0.35 cm3/g to 0.50 cm3/g and from 840 to 1096 m2/g respectively, this value is likely attributed to the high selectivity of CO2/CH4 and methane adsorption by combining large surface area, narrow micropores. The results of the stability tests attested to the robustness of activated carbon as an adsorbent under the specified operating conditions The assessment, which included measurements after the first cycle as well as the fifth, tenth, and fifteenth cycles, revealed a remarkable consistency in its adsorption behavior, with a maximum recorded standard deviation of 0.05. Isosteric heat showed a decline in Qst from 21 to 20 as surface coverage increases from 0.1 to 0.5, indicating the energetic transformation occurring during the adsorption process. Activated carbon AC C shows the highest methane capture capacity of 150 V/V at 40 bar pressures and CH4/CO2 0.49 selectivity up to 1 bar.

Carbon dioxide and methane capture in metal-organic framework MIL-101(Cr) at high pressure

Due to the presence of high CO2 amounts in the natural gas stream, a variety of efforts have been employed in the search for more efficient materials for the separation of gaseous mixtures such as CO2/CH4. In this article, a metal-organic framework (MIL-101) was synthesized and characterized, which showed a wide surface area (2924.8 m2 g−1 per BET) and a high volume of pores (1.32 cm³ g−1 per DFT). This structure was used to study the adsorption capacity of CO2 and CH4 within systems pressurized up to 100 bar - where a high adsorption capacity of CO2 was evidenced under 45 °C. Moreover, it was possible to distinguish between the high selectivity of this structure for CO2 molecules and its low capture of CH4 molecules. Also, the high stability of MIL-101 was noted after 6 cycles of adsorption and desorption of CO2 under 50 bar and 45 °C, thereby maintaining its adsorption capacity and crystallinity. Finally, isotherms of CO2 adsorption were successfully adjusted with the use of the Toth model.

Integration of in-situ and ex-situ power-to-gas (PtG) strategy for simultaneous bio-natural gas production and CO2 emission reduction

A novel system integrating an in-situ and ex-situ power-to-gas (PtG) system was developed in the current study. A continuous stirred-tank reactor (CSTR) was operated using cattle manure as substrate at mesophilic temperature (37 °C ± 2 °C). The CH4 content in the biogas was upgraded to above 95% by H2 injection, which meets the highest criteria for grid injection without requiring CO2 removal. Furthermore, the bio-nature gas production was promoted by external CO2 and H2 injection. The volumetric methane production rate (VMPR) was significantly increased by 739% from 117.4 mL L−1·d−1 to 985 mL⋅L−1⋅d−1, which is higher than in other studies. Meanwhile, the volumetric biogas production rate (VBPR) was increased by 36.9% by H2 injection, increasing the conversion efficiency (82.56%) of the chemical oxygen demand (COD) to CH4. A significant increase in the specific methanogenic activity of dissolved hydrogen (SMA(Hdissolved)) and the enrichment in hydrogenotrophic methanogens (Methanobacterium) demonstrate that the CH4 production pathway was converted from acetoclastic methanogenesis (AM) pathway to hydrogenotrophic methanogenesis (HM) pathway. It is postulated that the change in proportion of different pathways of the CH4 production was caused by the strengthening of key enzymes (coenzyme F420 hydrogenase and coenzyme-B sulfoethylthiotransferase) by H2 injection. The integrated system represents a promising approach to achieve simultaneous CO2 emission reduction and bio-natural gas production.