جستجوی مقالات مرتبط با کلیدواژه « بیوگاز » در نشریات گروه « مکانیک »

In this study, the combustion performance of C30 microturbine combustion chamber with biogas fuel with different mass fractions of CO2 has been analyzed and investigated. By assuming the periodic geometry and the two-stage reaction of fuel and oxide, the computational cost was reduced. To simulate the flow inside the chamber, three-dimensional Navier-Stokes equations and the k-ε turbulence model have been used to model the effects of turbulence. The flow inside the combustion chamber with different fuel components was analyzed with the EDDY DISSIPATION combustion model. To validate the solution and compare the results with the fabricated sample, pure CH4 was used as fuel. In this study, it was found that in the case of a constant mass flow rate of the consumed fuel, increasing the share of CO2 in the fuel with different mass fractions, due to the decrease in the calorific value created, caused a decrease in the production temperature, and it was also found that the use of biogas as a premix caused a decrease The amount of NOx becomes desirable. According to the obtained results, it is suggested that the amount of CO2 in the fuel is at most 10%, because the temperature has decreased by only 38 Kelvin and the amount of NOx in the output is 1.4 ppm.

The investigation of alternative fuels, such as biodiesel, have been prompted by the detrimental emissions resulting from the combustion of fossil fuels. Undoubtedly, the primary concern in fuel selection lies in the examination of emissions. Hence, the present study aims to examine the performance and environmental life cycle assessment methodologies of a dual fuel diesel engine. Furthermore, a fuel blend is made by combining biodiesel sourced from sunflower oil with varying concentrations of bioethanol (3%, 5%, and 7%) and pure biogas, with a percentage ranging from 50% to 80%. This fuel blend is intended for use in the combustion process. In this study, a total of eight fuel samples were meticulously produced and subsequently examined, alongside diesel fuel which served as the control fuel. The entire life cycle evaluation encompasses several stages, starting with the manufacturing of inputs to the combustion of fuel samples. This includes the extraction of oil from sunflower seeds, the production of biodiesel and bioethanol, as well as the generation of natural gas produced from pure biogas. These processes are regarded as captivating and pioneering topics within the field. The provided samples underwent combustion within a dual fuel engine. The findings indicate that the B5 fuel sample, when combined with a 3% bioethanol additive, demonstrates superior engine performance and reduced exhaust emissions. Furthermore, enhanced conditions were achieved in terms of engine performance and exhaust emissions when operating at the lowest rate of natural gas fractionation, which was 50%. The findings of a thorough life cycle evaluation, which examines the entire process from farm to combustion, indicate that the blend B5E7, consisting of 50% natural gas portion at maximum engine load, demonstrates both environmental friendliness and appropriate performance characteristics.

With the increase in energy consumption and wastes generation due to human activities, anaerobic digestion (AD), a technology which turns wastes into bio-energy, is receiving more and more attention in the world. Biogas is renewable, clean and relatively mature energy, but most biogas commercial plants still need significant financial incentives. In addition, a shortage of locally available, cheaper and digestible materials reduces biogas productivity, especially for large biogas plants (larger than 1 MWat). Therefore, innovations that can improve the cost and efficiency of biogas energy technology resources are needed. Over the past few years, a number of potentially innovative processes for biogas technology have been proposed and explored. However, most of these new concepts have had little impact on technology development. Therefore, it is necessary to review the reports that compare, analyze and evaluate the appropriateness of these methods and the technological superiority and real commercialization potential. This article reviews the latest innovations and articles related to biogas production. It also provides ideas for new innovations by identifying future research needs.

This paper presents a novel multi-generation system based on biogas fuel for simultaneous production of goods such as electricity, cooling, freshwater, and hydrogen using smart heat recovery of combustion gases. The performance of the proposed system is investigated in terms of the first and second laws of thermodynamics. Also, to acquire a comprehensive evaluation of operation costs, an exergoeconomic analysis has been performed. Furthermore, a comprehensive parametric study has been conducted to understand the behavior of the system performance parameters with the design parameters. In the following, to show the superiority of using a Stirling engine, the investigation of the present study is performed under two different scenarios. The proposed system could produce 986 kW, 137.5 kW, 8.39 m3/h, and 2.96 kg/h, net output electricity, cooling load, distilled water, and hydrogen while working with the Stirling engine. In this case, the energy and exergy efficiencies of the proposed system are obtained at 37.3% and 32.08%, which are improved by about 2.96% and 7.89%, respectively. In terms of cost metrics, the total unit cost of the products is about 0.1086$/kWh which has increased by 8.1% compared to the non-sterling engine mode.

Global economic development requires increasing water demand for various purposes. Wastewater treatment in these processes leads to an increase in the volume of sewage sludge. However, a significant amount of renewable energy can be recovered from sludge from wastewater treatment. Biomass is one of the energy sources that has the potential of sustainable replacement for fossil fuels, a significant part of which consists of municipal and industrial wastewater. Anaerobic digestion is used as a strategy to generate energy and biogas from municipal waste and sewage. In this study, the energy production potential of wastewater treatment plants in Khorramabad city has been investigated and evaluated using preliminary data (including BOD) on wastewater treatment performance over one year (2021). The results show that annually 2261728 cubic meters of biogas can be produced using the anaerobic digestion method. Using the combined heat and power system can generate 24879008 MW of thermal energy and 476.34 kWh of electricity. Also, the economic evaluation of the system shows that the annual investment costs and operating costs will be 103251697000 and 14620633 Rials, respectively. On the other hand, the refinery can save 44689938600 Rials annually by saving natural gas consumption, selling fertilizer produced, and selling electricity generated to the network. The rate of return on economic capital for implementing this plan is calculated for 3 years and 6 months. In addition to economic justification, implementing this plan will be able to prevent greenhouse gas emissions significantly.

Increasing energy consumption has led to the use of renewable energy sources to reduce environmental pollution and prevent global warming. The present work has been carried out with the aim of presenting and investigating a new combined cycle based on the gas turbine with biogas fuel and due to the high outlet temperature of the gas turbine, a steam Rankine cycle equipped with open feed water heater and the thermoelectric generator has been combined with it as the bottom cycle. The system is studied based on the variables of air compressor pressure ratio and air preheater temperature efficiency and analyzed from the viewpoint of the first and second laws of thermodynamics and thermo-economics. Also, to find the best-operating conditions, the system is optimized using the genetic algorithm in EES software by employing single and multi-objective optimization. The results showed that the thermal and exergy efficiencies in the base condition are 44.58 and 42.38%, respectively, and in the optimum thermo-economic condition are 49.45 and 47.01%, respectively. In addition, the LCOE in the multi-objective optimization condition was calculated at 17.50 $/GJ, which is 5.1% lower than the baseline.

Nowadays, one of the suitable technologies in terms of power generation and saving energy with high efficiency is using the multigeneration systems that renewable fuels are used as an alternative to fossil fuels. In the present study, a multigeneration system including biogas fired gas turbine, Organic Rankine Cycle (ORC), domestic water heater, Reverse Osmosis (RO) unit and Proton Exchange Membrane (PEM) electrolyzer. The proposed multigeneration system is assessed from energy and exergy viewpoints. After that, a comprehensive parametric study is carried out to show the effects of some key parameters (including pressure ratio of compressor, condenser pressure, evaporator temperature, preheater temperature and inlet temperature of gas turbine) on main performance criteria of the multigeneration system. Finally, the multi generation system is optimized from thermal efficiency point of view. The optimization results indicate that the thermal efficiency has optimum values for evaporator temperature and pressure ratio of compressor. Also, results show that the values of generated power, produced fresh water, thermal efficiency, exergy efficiency, produced hydrogen and total exergy destruction are calculated as 1192 kW, 5.584 kg/s, 55.74%, 30.56%, 1.455 kg/hr and 2827 kW, respectively.

The use of organic fraction municipality solid waste (OFMSW) in the process of anesthetic digestion (AD) can be a good way to manage and extract energy. In the present study, the effect of adding ZnO nanoparticles (ZnO) nanoparticles and iron oxide nanoparticles (Fe3O4) and cobalt oxide nanoparticles (Co2O3) on the production of biomass and biomass from anaerobic digestion organic fraction municipality solid waste (OFMSW) and cattle manure (CM) reviewed and studied. The results showed that using nanoparticles with low and essential nutrients with optimal concentrations in digesters could potentially have positive effects on the stability of the digestion process, the reduction of further impurities and pollutants in the biogas, reduction of volatile fatty acids (VFA) and biogas production has been increased. Due to the toxicity of ZnO nanoparticles on bacterial bacteria in the first days, it directly affected the toxicity of bacterial bacteria and reduced the production of biogas. But after a few days, bacterial bacteria became familiar with the toxicity of added substances and were able to survive in such conditions, and increased the production of biogas. The anaerobic digestion process is highly dependent on nanoparticles. Increasing the iron oxide nanoparticles (Fe3O4) and ZnO nanoparticles (ZnO) and reducing the cobalt oxide nanoparticles (Co2O3) have a positive effect on the biogas production rate and methane yield. The best concentration of nanoparticles for the biogas production rate and maximum methane yields are 20-28 milligrams of iron oxide nanoparticles (Fe3O4) for zinc (ZnO) 0.8 to 1.5 nanoparticles and 0.25 to 0.35 milligrams for cobalt oxide nanoparticles (Co2O3). Most produced biogas and methane were obtained during the digestion process at the points mentioned..

In the last decade, renewable energy sources have been proposed as an appropriate alternative to meet the energy needs of remote rural areas. The present work focuses on the feasibility of locally available renewable energy production systems development (including solar systems and biomass resulted from manure dung). The studied rural area, Eastern Alamut, located in Qazvin province and consists of three cold and impassable villages of Pichebon, Narmelat and Dinheroud. In order to fulfill energy supply of the rural region, three scenarios have been presented and related techno-economic analyses have been done. Firstly, all heating (cooking and hot water are included) and electricity demands have been met solely by photovoltaic system. In the second scenario, heating and electricity have been supplied by biogas as well as CHP system. Moreover, the heat loss of CHP has been used to warm up the digester. In the last survey, the electricity need has been supplied by photovoltaic system along with covering heating demand through biogas. In this scenario, the required heat to operate digester is provided using the photovoltaic system. In each scenario, volume of digester and equipment of solar system have been calculated. The techno-economic analysis shows that the second scenario that has a positive Net Present Value in each discount rate (5%, 10% and 15%) and Internal Rate of Return is 24.24% 23.26% and 38.6% for Pichebon, Narmelat and Dinehroud villages, respectively, is as a practical design and economic option.

The purpose of the present research is to perform the energy analysis of a Combined Heat and Power (CHP) plant using a Solid Oxide Fuel Cell (SOFC) system fed by biogas from a Waste Water Treatment Plant (WWTP) and a solar system. CHP is a reliable and cost-effective option for WWTPs where anaerobic digesters are equipped. Biogas produced in WWTPs can be utilized to fuel a CHP system to produce electricity and useful thermal energy using a variety of prime movers. The thermal energy produced by the CHP system can be used to meet a part of the anaerobic digestion process heat demand in the WWTP digester. In the present study, a steady-state model is developed for the fuel cell simulation and the integrated plant system. Tabriz WWTP is studied in this work. Three SOFC modules produce, in cogeneration mode, 180 kW electricity and 125 kW thermal energy. The results show that supplying a part of the digester heat demand through solar energy can save natural gas combustion in the plant.

Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. The purpose of this study was investigation the feasibility of biogas production from domestic wastewater in an industrial unit. In this research, firstly the characteristics, production sources, importance, usage and models of biogas production systems were studied. Then, the calculations related to the amount of biogas production of the mentioned industry were performed based on influent and effluent wastewater flow rate and biological tests. According to the results, because of the low flow rate of influent wastewater, the amount of produced biogas production was not considerable and it could not supply the heating/cooling demand of the industrial unit and only the electrical energy of the lighting of the area will be supplied by the energy of produced biogas. However, in terms of reducing greenhouse gas emissions, the production of liquid and solid contaminated solid fertilizers can be considered. However, if the wastewater is added to the wastewater of adjacent animal husbandry, poultry houses and slaughterhouses and the flow reaches at least 1300 m3 per day, the biogas production will be considerable and economical.

An experimental investigation has been done on the effective parameters on biogas extraction from the combination of food waste (FW) and cow manure and organic. Samples of FW were collected from the university restaurant and they mixed with the manure with different ratios of 1: 1, 1: 2, 1: 3, 3: 1 in a 1 liter polymeric bottles. These bottles embedded in a hot water bath at a thermophilic temperature of 55-60 ° C in a period of 15 days. The volume of biogas produced was measured. The results of gas production showed that the ratio of 1: 1 obtained the highest volume of cumulative gas ( 5 liters). Ten grams of chemical additive of silica gel and organic additives like rosemary plant, walnut shells, banana and tomato skin were added to the optimum selected ratio of digester. The produced cumulative biogas was increased 24.4%, 7.2%, 2.3%, 1.9%, 6.6% by volume respectively in compare with that of optimum based mixture. During the digestion period, PH changes showed that the highest volume of biogas was generated in neutral pH. And the use of walnut shells resulted in PH stabilization in the process. Measuring thermophysicsl properties (Total solids, volatile matter, moisture content, ash content), for the mixture of food waste and manure were shown the high capacity of food waste to convert to biogas (43%) Based on the laboratory experiments, energy analysis was performed for portable biogas reactor.

In this paper, a novel biogas steam reforming system for producing hydrogen is presented. The mixture of biogas contains a largepercentage of Methane, Carbon Dioxide,negligible amounts of other gases. A thermodynamic comprehensive modeling (energyand exergy) was done on the suggested system. The impact of various system parameters in the mixture of biogas such as,temperature,molar ratio of carbon dioxide to methane is also done on the hydrogen production rate, energy,exergyefficiencies of the entire system. The results show that by increasing the temperature of the steam reforming reaction in reactor, in aconstant molar ratio of carbon dioxide to methane in the mixture of biogas, hydrogen production rate,energy,exergyefficiences are increased. Moreover, increasing the molar ratio of carbon dioxide to methane in the biogas combination at hightemperatures, resulted a decrease in hydrogen production per mole of methane,so the energy,exergy efficiencies of the entiresystem (decreased). As well as the most energy,exergy efficiencies of the whole in the case of hydrogen production is maximum,achieved to 52%,42%, respectively.

In this study, the production of biogas from vinasse by using three SGBR reactors with the same volume of 5.6 liters for three hydraulic retention times (2, 3 and 4 days) and organic loading rates of 86002, 28667 and 21500 mgCOD/L.d was investigated. The water bath method was used to provide the temperature of mesophyll reactors at 35, and NaOH solution was used for buffer. The biogas volume was measured using the water displacement method. The results showed that the methane production was almost constant with HRT of 4, 3, and 2 days after 11, 13, and 16 days, respectively. Methane gas production with HRT of 2, 3, and 4 days was 6.66, 16.66 and 27.38 LCH4(STP)/L.day per liter of vinasse, respectively. For three reactors, methanogen and acidogenic bacteria were in the equilibrium state at pH 5.57 after 2 days. The amount of methane gas production per volatile solids with the HRT of 2, 3, and 4 days was 244, 345 and 434 m3CH4/gvs, respectively.

Limitation of fossil fuel resources together with commitment to conservation of environments have caused the views to be focused on the use of renewable energy resources. Biogas is produced by the anaerobic decomposition of organic matter in WWTPs (wastewater treatment plants) and is considered to be a sustainable energy resource due to permanency of wastewater flow. This research focuses the process of biogas fuel engine implemented in Kashan WWTPs. This system can reduce the fuel consumption rate and use renewable energies in production of heat and electrical power reliable a part of processing consumption of WWTPs. Specifications of biogas production in Kashan WWTPs is taken as sample and the necessary elements for installation and construction of biogas fuel engine are described and then two cogeneration units are designed for producing 466 kW electricity and 556 kW heat.. Costs of installations and total capital investment required for this power plant is calculated about 270,000$, which can be returned in 4 years through sales of electricity and other by-products. Also using wastewater for producing biogas reduces greenhouse emission such as methane and carbon dioxide.

Current study aims to numerically investigate the steady state performance of integrated cycle consisting of biomass gasification process and planar type solid oxide fuel cell for different biomass moisture content and amount of air as gasification agent in the gasifier. Single stage lumped gasifier is analyzed by use of a modified thermodynamic equilibrium model, while the steady-state intermediate temperature solid oxide fuel cell model developed hear is one-dimensional which allows for monitoring of the temperature gradients along the cell length under different operating conditions. Complete electrochemical model, species mass balances and energy conservation equation beside the kinetics describing internal methane steam reforming and water-gas shift reactions organize the structure of fuel cell model. Developed model for two main parts of the integrated cycle are validated against the available experimental and numerical dates. Results indicated that the low heating value of the product syngas with 30% moisture content decreases with decreasing of the modified equivalence ratio and increasing of the biomass moisture content from 10 to 50%. Based on the obtained results, the cell electric power mitigates by increasing of the biomass moisture content.

In recent years, the growing rate of fossil fuels consumption all over the world has faced the humankind with two big crises: environment pollution and increasing rate of resource depleting. Therefore, movement towards clean and renewable energies is a top priority decision in the world. Biogas is one of these energies, which is flammable blend caused by fermentation of organic materials in a given temperature range and exact PH in anaerobe environment in presence of microbes. Fermentation reaction inside biogas production unit consists of chemical and biological activities of two groups of acid and methane-generating bacteria. Bacteria growth and survival and also the amount of biogas depend on fermentation environment condition. Separation of H2S, CO2, and steam from biogas is essential, otherwise, the gross amount of methane will be higher and then its heating value will be decreased. The biogas is a colorless and odorless gas without any smoke which has heating value of about 4580-5495 kcal/m3 for 50% to 65% purity of methane. Biogas can be utilized for thermal applications, as fuel for internal combustion engines and electricity production units and also providing raw materials for chemical industries and organic fertilizer production.