Conversion Of Municipal Solid Waste Research Articles

Decoupling study of municipal solid waste gasification: Effect of pelletization on pyrolysis and gasification of pyrolytic char

To explore the influence of pelletization on the thermal conversion of municipal solid waste (MSW), pyrolysis characteristics and gasification reactivity of MSW pellet and powder were investigated in this study. Besides, the physicochemical properties of internal char and external char within the char pellet were separately characterized. Moreover, the relationship between the physicochemical properties of char pellet and its gasification reactivity was clarified. Results showed that the pyrolytic gas yields of MSW pellets were increased by 15.47 % and 11.55 % at 700 °C and 800 °C, respectively, compared to powder MSW. It was mainly attributed that the conversion of monocyclic aromatic hydrocarbons to polycyclic aromatic hydrocarbons was promoted by the longer residence time within the pellets. Meanwhile, the physicochemical properties of pyrolytic char pellets exhibited a significant heterogeneity. Specifically, the number of ordered aromatic rings of char pellet was reduced, while the order degree of carbon structure was enhanced, particularly the internal char. However, the difference magnitude between internal and external char was diminished with temperature. This was due to the higher temperature resulting in a larger surface specific area and pore volume of the char pellet, especially the internal char, thereby enhancing the pyrolysis process. Furthermore, an increase in pore volume within the char pellet improved gasification reactivity when the conversion rate > 0.4. These findings provide a reference for the pyrolysis and gasification process of MSW pellets.

Sustainable energy recovery from municipal solid wastes: An in-depth analysis of waste-to-energy technologies and their environmental implications in India

In recent years, in response to an increased demand for renewable energy sources, there has been a rise in the rate of energy recovery from municipal solid trash. This study analyses the feasibility of employing a variety of energy recovery methods to produce clean power from municipal solid waste (MSW). The conversion of MSW into a variety of useable sources of energy, such as fuel, heat and electricity, is required for the process of energy recovery. Other strategies for the recuperation of lost energy include gasification, incineration, anaerobic digestion, and the recovery of landfill gas. This article provides a high-level assessment of the advantages and disadvantages associated with each technology that is currently being utilised in India. According to the findings of the study, recovering energy from municipal solid waste is a sustainable and cost-effective option that can fulfil the growing demand for power while simultaneously lowering emissions of greenhouse gases and the amount of rubbish that ends up in landfills.

Preliminary findings on the potential of converting municipal solid waste into refuse-derived fuel as an alternative renewable energy source from the Jakarta waste case study

Abstract The conversion of municipal solid waste (MSW) to refuse-derived fuel (RDF) is a promising technology for addressing waste management issues and obtaining a sustainable source of renewable energy. However, the implementation of RDF technology for MSW management in Indonesia, particularly in urban areas, has not yet been realized. This study aims to evaluate the viability of producing RDF from MSW, specifically the waste generated by Jakarta city, which is representative of other large cities in Indonesia. The research analyzed the MSW, including its physical and chemical properties, such as composition, proximate and ultimate analysis, and energy content. In order to investigate the potential adoption of bio-drying technology for the production of RDF from waste in Jakarta, a pilot scale experiment was conducted using a batch system. The results of the characterization indicate that the sample comprises of more than 50% organic waste, and furthermore, the moisture content in the samples is greater than 60%. The waste typically contains a carbon content of around 50% and a calorific value of approximately 1400 kcal/kg. RDF products produced through bio-drying can achieve a moisture content of 37.88% and a heating value of 2675 kcal/kg. The results further emphasize the potential of the produced RDF as a feasible source of renewable energy.

MSW-TO-RDF CONVERSION FOR CEMENT PLANT IN INDONESIA THROUGH PILOT PROJECT AND MODELING

Aiming for sustainable MSW and cement industry practices, this study assessed the conversion of municipal solid waste (MSW) to refuse-derived fuel (RDF) in four major Indonesian areas. Physical and chemical properties, particle size distribution, and MSW fraction analysis were performed to characterize the MSW before utilizing the MSW for the pilot project. In the pilot project, MSW was shredded and separated to produce RDF and low-grade RDF. RDF produced was quantified, and the output was analyzed to determine the RDF quality. RDF modeling was set based on the pilot project outcome, where the potential quantity, analysis, and feasibility were evaluated. The analysis revealed a need for better MSW processing due to a low heating value (LHV) of 5.4 MJ/kg and high moisture content (MC) of 52-57%. Combustible materials were found to be crucial for RDF quality. A pilot processing 1,000 Mg of MSW resulted in RDF with an LHV of 8.7 MJ/kg and MC of 47% and low-grade RDF with an LHV of 3.0 MJ/kg and MC of 61%, highlighting the importance of drying phase to meet quality standards. The modeling incorporated a two-step drying process, including hot gas utilization at the cement plant. 13 RDF units processing 6,500 MSW Mg/day were needed to produce 3100 Mg/day of RDF (equal to 50% fuel substitution), which could significantly reduce CO2 emissions and MSW by 45% in Jakarta and its neighboring cities, marking an effort for eco-friendlier cement manufacturing.

Pyrolysis behavior of densified refuse-derived fuels (d-RDFs) via TGA: Investigating the impact of densification degree on thermal kinetics and thermodynamics

The conversion of municipal solid waste (MSW) into its energy-rich fraction, known as refuse derived fuel (RDF), addresses both MSW management and energy demand. RDF comprises a diverse blend of various non-hazardous waste streams, making it challenging to predict physical properties and chemical compositions. However, densification can help overcome these challenges. This work aims to explore the effect of densification degree on kinetic and thermodynamic parameters during the degradation of densified refuse-derived fuels (d-RDFs) in inert atmosphere. Herein, three d-RDFs samples obtained with varying degree of densification and die temperatures ranging from 55 °C to 118 °C, as well as a mixed fines (MF) sample produced during the pelletization process, were analyzed. Pyrolysis potential of d-RDFs and MF were determined using thermogravimetric analysis in the temperature range from 30 to 800 °C, at multiple heating rates of 5, 10, and 20 K min−1. The effect of the degree of densification on physical characteristics, and kinetic and thermodynamic parameters of d-RDF was investigated. Apparent activation energy (Eα) was estimated employing Friedman (FR), Kissinger-Akahera-Sunnose (KAS), and Flynn-Wall-Ozawa (FWO) methods. Derived Eα values were used to determine the pre-exponential factor (Aα) using the Kissinger method. Experimental results revealed that the durability of d-RDFs increased from 79.26 % to 98.73 % as the densification degree increased from II to IX. Furthermore, the Eα values exhibited a decreasing trend in the first peaks of the DTG profiles, while an opposite trend was observed in the second peaks of DTG curves. However, with an increase in the degree of densification, the mean values of Eα decreased by 5–10 % for all methods. The Aα values, assessed using the FR method, surpassed the critical value of (109 s−1) for all samples. However, with the KAS and FWO methods, these values fell below (109 s−1) within the conversion range of 0.05–0.25. Thermodynamic parameters confirmed the endothermicity of the thermal degradation process.

Chemical characterization of refuse derived fuel (RDF) using Py-GC/MS

The conversion of municipal solid waste (MSW) to refuse-derived fuel (RDF) and its utilization as an alternative fuel in the cement industry has been an emerging trend. However, RDF is highly heterogeneous, with its complex composition changing with season and source. This work is focused on the chemical characterization of six RDF samples listed as A, B, C, D, E, and F from different locations across the country using pyrolysis gas chromatography-mass spectrometry (Py-GC/MS), thermogravimetric instrument and CHONS elemental analyzer. Qualitative and semi-quantitative results were obtained using EGA, single-shot and double-shot analysis methods. EGA has been used to derive qualitative results in correlation with TGA. FTIR analysis was carried out to understand the initial functional characterization. XRF analysis along with ICP-MS triple quad revealed the inorganic makeup of the samples. Single-shot results indicated that apart from non-hydrocarbon gases (CO2 and O2), the long-chain alkenes were most abundant, followed by alkanes, aromatic compounds, and ketones. Double-shot analysis indicated the presence of chloride and sulphur-based compounds in RDF samples as limiting components. Polystyrene contribution to LHV of RDF has been highlighted. The study can be further used to conduct compositional studies of RDF and its pyrolytic behavior in the gasifier. It will further strengthen the future gasifier models where pyrolysis is one of the critical steps. This technique will be very helpful in obtaining a better characterization of volatile and non-volatile (bio-oil and ash) fractions of the pyrolytic products.

Process modelling of waste tyre pyrolysis for gas production using response surface methodology

The search for cleaner and renewable energy sources coupled with the need for environmental protection has necessitated the conversion of municipal solid wastes to energy sources. In this study, the pyrolysis of waste tyres in a fixed-bed reactor was carried out in a bid to generate non-condensable gases. The influence of process variables such as sample weight, reaction temperature, and reaction time were modelled and optimized using the central composite design of the response surface methodology. Based on the central composite design of the response surface methodology, the R2, adjusted R2 and predicted R2 values of 0.968, 0.941 and 0.750 respectively, indicated that the model properly fitted the experimental data. This implied the accuracy of the model prediction. The maximum predicted gas yield of 10.212 wt% was estimated under optimal conditions with desirability of 0.697, a dimensionless value indicating the closeness of the combination of input variables to the desired values for the response variables. The gases obtained upon pyrolysis of waste tyres can serve as a source of hydrocarbon gases in the petroleum and petrochemical industry.

Producing methane from dry municipal solid wastes: A complete roadmap and the influence of char catalyst

The lack of standardized products is a key hindrance to the widespread commercialization of municipal solid wastes (MSW) pyrolysis technology. In this paper, a cost-effective roadmap employing pyro-gasification and methanation processes is developed, with CH4-rich gas as the target product. In this roadmap, a two-stage catalytic conversion of “MSW → syngas → CH4-rich gas” was realized using MSW char, a by-product of the pyrolysis process as the catalyst/catalyst carrier. The results showed that, in the pyro-gasification stage, a syngas yield of 1.3 L/gMSW could be obtained at 800 °C and a steam-to-MSW mass ratio of 0.4, with a H2 fraction reaching 56.6 vol%. The effective conversion of MSW to syngas was attributed to the superior catalytic activity of the MSW char. By comparing the catalytic activity and structural characteristics of the chars produced from various waste components, it could be determined that the high catalytic activity of the char required both active minerals derived from contaminated plastics and residue, and an appropriate proportion of carbon matrix from the biomass components in MSW. The gasified MSW char (G-MSWC), co-produced with the syngas, served as a carrier for the subsequent methanation catalyst. Due to the activation effect of steam during the syngas production stage, the pore structure of G-MSWC was improved and its defect density also increased. Consequently, G-MSWC demonstrated enhanced Ni–C interaction, facilitating the methanation activity. The final product from the methanation stage achieved a CH4 concentration of 52.9 vol%, and a CH4 yield of 11.25 mol/kgMSW. The above findings demonstrate the feasibility of the complete roadmap from MSW to CH4 and provide valuable guidance for decentralized MSW management based on pyrolysis technology.

Sustaining environment through municipal solid waste: evidence from European Union economies.

As part of their pursuit to succeed the Sustainable Development Goals (SDGs), European Union (EU) countries have placed great importance on realizing SDG 11, which aims to create sustainable cities and communities. The relationship between environmental quality and municipal solid waste remains understudied despite its significant impact on achieving SDG-11. Consequently, this study seeks to peruse municipal solid waste, renewable energy consumption, human capital, and natural resources impact on load capacity as a comprehensive measure of environmental quality. By utilizing the CS-ARDL approach, this study reveals the inadequacy of municipal solid waste conversion in EU countries and highlights the favorable effect of human capital and renewable energy on enhancing environmental quality. Moreover, this study provides concrete evidence that natural resources contribute to environmental corruption. EU economies should adopt policies to bolster municipal solid waste conversion to improve environmental quality.

A machine learning study on a municipal solid waste-to-energy system for environmental sustainability in a multi-generation energy system for hydrogen production

Municipal solid waste (MSW)-to-energy systems have gained significant attention in recent years for their potential to produce renewable energy from waste. These systems involve the conversion of MSW into electricity, heat or fuel. One of the most promising applications of MSW-to-energy systems is the production of hydrogen, which is considered a clean and sustainable fuel. Machine learning algorithms have the potential to revolutionize the way MSW-to-energy systems are managed. The integration of machine learning into MSW-to-energy systems has the potential to significantly improve the sustainability and profitability of this industry. In this study, a novel integrated MSW-to-energy system is modeled to produce hydrogen, power, and oxygen and with capacities of heating water and air. Hydrogen production, power production, oxygen storage, hot water, hot air, and system emission are predicted using machine learning algorithms based on regression models with high validity and R2 values more than 99.8% having errors smaller than 1%. The reduced regression models are developed by eliminating the insignificant variables from the full algorithms using the analysis of variance. The findings reveal high accuracy for the reduced regression models while their errors slightly decrease to 2%. This suggests that the machine learning algorithms can also be used as an effective tool to further improve MSW-to-energy systems.

The development of an integrated GIS-based optimization framework for power generation from municipal solid waste-to-energy facilities

Waste-to-energy (WtE) is one of the municipal solid waste (MSW) management pathways that can reduce waste volumes while recovering energy. There has been considerable focus on using MSW for energy production; however, there are few integrated assessments of the optimal location and scale of the conversion of MSW to energy. This research develops a novel framework that integrates the analysis of candidate sites for MSW gasification facilities using a geographical information system (GIS) through a multi-criterion decision-making (MCDM) model with a mixed-integer linear programming (MILP) model to determine optimal scale and location. The most suitable candidate locations were identified through a GIS-based location-allocation analysis. A MILP model integrated with GIS was then used to determine the minimum per-unit electricity production costs by optimizing the numbers, locations, and sizes of the proposed WtE and preprocessing facilities. The key inputs to the optimization model are actual road and railway transportation distances, WtE gasification and preprocessing facility capital and installation costs, operation and maintenance costs, gate fee and tipping fees (the fee for disposal of ash at the landfill), and the municipal guidelines. The proposed integrated framework was applied in a case study for Alberta, a western province in Canada. The results indicate that at a 10% rate of return, electricity production is cost-competitive with current electricity prices. The per-unit cost of electricity production (COEP) was found to be only 16.14 $/MWh when the gate fee was treated as a revenue component. The optimal plant location was in Edmonton and the optimum plant size was 175 MW. Sensitivity and uncertainty analysis was conducted to understand the critical input parameters that impact the COEP. The results indicate that the COEP is most sensitive to changes in tipping fees, plant efficiency, capital cost, discount rate, and transportation cost. The developed framework is critical for investment decisions and policy development, and it can be applied globally with adjustments to data and assumptions.

Development of data-intensive techno-economic models for the assessment of a biomass, waste heat, and MSW integrated waste-to-electricity facility

This study develops a framework for an assessment of the integrated processing of various types of waste in a single waste-to-energy (W2E) facility. The FUNdamental ENgineering PrinciplEs-based model for Estimation of Cost of Energy from Biomass and Municipal Solid Waste (MSW) (FUNNEL-Cost-Bio-waste) was developed and used to assess the conversion of MSW, agricultural residue, forest residue, and waste heat to electricity via gasification. A geographic information systems (GIS)-based model was developed to estimate the availability of wastes at collection points and the transportation distances to the facility. A case study for Alberta (Canada) was conducted to assess the techno-economic feasibility of a 199 MW gasification-based facility. Depending on whether one or two waste heat sources are used for drying MSW, internal rates of return and the costs of generating electricity were estimated to be 11.18 % and 8.09 % and US $21.90/MWh and US $33.23/MWh, respectively. This information can be used for investment decision-making.

Sustainable production of hydrogen, pyridine and biodiesel from waste-to-chemicals valorization plant: Energy, exergy and CO2-cycle analysis

This study deals with the simulation of waste-to-chemicals plant for the conversion of municipal solid waste to hydrogen, biodiesel and pyridine. The study analyses a Waste to Chemical plant, in order to evaluate the future scenarios of the integrated management of municipal waste from a technical and economic point of view and compare them, both in terms of material flows and related costs. In a first phase, the characteristics of the simulation model created with the help of the Aspen Plus software are analysed. Subsequently, with the help of a calculation model, the operating costs, emissions and energy and exergy efficiency are evaluated for the two identified scenarios.Starting from about 3000 t/h of waste, as a main result, about 8.4 t/h of pyridine and 300 t/h of biodiesel are produced and about 7.94 t/h of H2 as a by-product. The main purpose of the design cycle is to reduce the amount of waste to landfill, valorising it and limiting CO2 emitted in the atmosphere at the same time.Two system configurations are considered to maximize the reuse of all waste streams. In particular, the comparison was made between two scenarios: in the first the stream separated by extraction is considered a waste for the plant, while in the second scenario, this stream is sent to a fermentation section to obtain an excess bioethanol stream, which represents another product with high added value. The treatment of the stream separated from the extraction in the second scenario allows to obtain an additional stream of bioethanol in addition to the target products.A complete energy, exergy, environmental and economic analysis of the simulated plant have been carried out. The work shown that in the second case the waste exergy is dramatically reduced, leading to a raise of exergy efficiency from 30.2% up to 84.9%. While, from the environmental point of view both scenarios have low CO2 emissions, 0.52 kgCO2/kg products and 0.87 kgCO2/kg products respectively.

Importance of Microalgae and Municipal Waste in Bioenergy Products Hierarchy—Integration of Biorefineries for Microalgae and Municipal Waste Processing: A Review

In the context of global advancements, the imperative of a sustainable energy supply looms large. Biomass, an adaptable and renewable resource, has garnered attention for its potential contributions, although economic uncertainties persist due to the intricate web of processing pathways. In response, the biorefinery concept emerges as a structured strategy to optimize the processing of microalgae and municipal solid waste (MSW), capitalizing on their multifaceted potential to yield diverse end-products. This review underscores the critical significance of a cohesive biorefinery paradigm that unites the processing of microalgae and MSW, unveiling their capacity to generate a spectrum of high-value products. The utilization of mixed-integer linear programming paves the way for an optimal biorefinery model that navigates through complex decisions. Challenges encompass the array of diverse feedstocks and the preliminary nature of data availability. The overarching goal of this research is to discern optimal pathways for the conversion of MSW and microalgae into energy and valuable products, with a focus on enhancing waste utilization and augmenting the energy supply. In the broader landscape, this comprehensive review advances strategies for sustainable energy generation and waste management, invigorating innovative approaches to shape future progress. By illuminating pathways towards maximizing the potential of biomass resources, this review contributes to the ongoing discourse on sustainable energy and waste utilization.

Brief Overview of Refuse-Derived Fuel Production and Energetic Valorization: Applied Technology and Main Challenges

A large part of municipal solid waste (MSW) still goes to landfills, representing an environmental concern. A circular economy approach can enable safe management of MSW while mitigating the increasing energy needs when waste is used as a feedstock in energy production processes (waste to energy). Currently, MSW can be converted into refuse-derived fuel (RDF) through mechanical and biological treatment processes. This study analyzes the status of MSW and RDF production, as well as its main destinations in Portugal and Europe. The legislation applied, possible energy-recovery routes, and challenges associated with energy recovery are discussed throughout this paper. This research finds that the production of RDF in Portugal has been neglected, mostly because of RDF composition being quite heterogeneous and its poor fuel properties. Therefore, the need to improve and upgrade the characteristics and properties of RDF for waste-to-energy processes was detected. RDF can be pretreated to be further applied to waste-to-energy and waste-to-gas processes, such as incineration and gasification. The technology readiness level data, costs, and SWOT analysis allowedto assess that although incineration is the most mature and widely used technology, gasification becomes more attractive, having lower costs and gaseous emissions, proving to be more efficient and sustainable for MSW and RDF conversion.

The Thermochemical Conversion of Municipal Solid Waste by Torrefaction Process

In this work, the thermochemical properties of municipal solid waste (MSW) are studied using the torrefaction process as the main method for investigation. Torrefaction experiments were carried out using an electric laboratory furnace, at temperatures of 200, 250, and 300 °C. The residence time was set to 90 min. Proximate and ultimate analysis were performed on the torrefied MSW samples and compared with the properties of the raw MSW samples. In addition, the thermal properties of the obtained torrefied MSW samples were evaluated by thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). The following could be stated: the obtained results showed that mass and energy yields (MY and EY, respectively) decrease with increasing when torrefaction temperature, while the heating values (HHV) increased under the same conditions (from 24.3 to 25.1 MJ/kg). Elemental analysis showed an increase in carbon content (C), from 45.7 ± 0.9 to 52.8 ± 1.05 wt.%, and decrease in oxygen content (O), from 45.6 ± 0.9 to 39.5 ± 0.8 wt.%, when torrefaction temperature is increased, which is consistent with the general definition of the torrefaction process. In addition, enhancement factors (EFs) and fuel ratios (FRs) were calculated, which ranged from 1.00 to 1.02 and 0.16 to 0.23, respectively. Some anomalies were observed during the thermal analysis, which are assumed to be related to the composition of the selected MSW. This study therefore shows that torrefaction pretreatment can improve the physicochemical properties of raw MSW to a level comparable to coal, and could contribute to a better understanding of the conversion of MSW into a valuable, solid biofuel.

Economic evaluation of thermochemical conversion of municipal solid waste to syngas: a case study of Cape Town municipality

Economic evaluation of thermochemical conversion of municipal solid waste to syngas: a case study of Cape Town municipality

Life cycle analysis of gasification and Fischer-Tropsch conversion of municipal solid waste for transportation fuel production

Non-recyclable municipal solid waste (MSW) can be used as feedstock for liquid fuel production via gasification followed by Fischer-Tropsch (FT) processes. Given the heterogeneity of MSW material composition and variation in material properties, its convertibility to liquid hydrocarbon fuels could vary widely, affecting the sustainability of utilizing non-recyclable MSW for fuel production. This study evaluates the life cycle greenhouse gas (GHG) emissions (carbon intensities [CIs]) of FT fuels from non-recyclable MSW. Key issues that could greatly affect the CIs were examined, including fossil carbon content of the MSW, emission implications of diverting non-recyclable MSW from landfills to fuel production, and conversion efficiency. Results show that the CIs of fuels produced from various waste streams range 80–105 gCO2e/MJ, which may exceed the CI of petroleum fuels. Higher fossil carbon content in the MSW feedstock tends to incur higher GHG emissions as biogenic carbon emissions are considered carbon neutral. Meanwhile, diverting different fractions of non-recyclable MSW, such as food waste and low-quality paper, from landfills may result in GHG emissions that may include the potential avoidance of methane emissions and potential sequestration of biogenic carbon that is foregone. To reduce GHG emissions, a carbon capture and sequestration option in the fuel production stage is considered, which could reduce the CI by 53–64 gCO2e/MJ. Carbon fates of different non-recyclable MSW in landfills are further evaluated to determine how they vary and impact the CIs of MSW-derived fuels.

A comparative techno-economic assessment of fast pyrolysis, hydrothermal liquefaction, and intermediate pyrolysis of municipal solid waste for liquid transportation fuels production

The conversion of municipal solid waste (MSW) to transportation fuels can be an attractive route to reduce greenhouse gas emissions from the transportation and municipal sectors. Thermochemical conversion routes like hydrothermal liquefaction (HTL), fast pyrolysis (FP), and intermediate pyrolysis (IP) have been shown to be adept at converting organic dominant MSW into bio-crude or bio-oil. However, to produce compatible transportation grade fuels, it is necessary to upgrade the intermediate product (bio-crude or bio-oil) from all the processes, the extent of which differs depending on the process. Moreover, depending on the conversion technique, the production configuration can be either centralized or decentralized. In a centralized system, feed is transported to a facility to produce the intermediate and upgrade it (on-site upgrading), while in a decentralized system, the intermediate is produced elsewhere and transported to an upgrading facility (off-site upgrading).. Four scenarios were developed and modeled to compare the cost of production of gasoline, diesel and jet fuel from bio-crudes produced from HTL, FP, and IP.. The scenarios are: 1) a centralized HTL plant (C-HTL); 2000 dry t per day; on-site upgrading, 2) a centralized FP plant (C-FP); 2000 dry t per day; on-site upgrading, 3) a decentralized FP plant (D-FP); 50 dry t per day; off-site upgrading, and 4) a decentralized IP plant; 12 dry t per day; off-site upgrading.. Jet fuel was the primary fuel for comparison and the production costs were calculated to be $ 0.72, $ 0.85, $ 1.04, and $ 0.81 per liter for the C-HTL, the C-FP, the D-FP, and the D-IP plants, respectively. Secondary products (gasoline and diesel) can be produced alongside in cost ranges of $ 0.97 - $ 1.40 per liter and $ 1.02 - $ 1.47 per liter, respectively. The information conveyed in this study helps to identify the potential of thermochemical conversion processes to produce transportation fuels at competitive prices. The critical barriers to adopt such large-scale production processes and the opportunities of small-scale decentralized production are also mentioned. The outcomes of this study can be used to direct research and investment to address the major roadblocks that are slowing the extensive development of these technologies.

Development of a MSW-fueled sustainable co-generation of hydrogen and electricity plant for a better environment comparing PEM and alkaline electrolyzers

Efficient conversion of Municipal Solid Waste (MSW) into useful energy by anaerobic digestion is a sustainable method which received growing interest, particularly for small-scale decentralized energy systems. This paper aims at development of an efficient combined cogeneration cycle for production of electricity and hydrogen from biogas generated using anaerobic digestion of MSW. When it comes to the topping cycle, the proposed system makes use of a micro gas turbine, whose waste heat is converted to electricity by an absorption power cycle. This additional electricity is provided to a water electrolyzer, which uses it to generate hydrogen. Two types of electrolyzers, including the Proton Exchange Membrane Electrolyzer (PEME) and the Alkaline Electrolyzer (AE) are considered, and their performances (as a component of the overall suggested combined systems) are compared from economic and thermodynamic viewpoints. The CO2 emission index is also addressed, and tri-objective optimization based on exergy, cost, and emission indices is carried out to compare the two systems. Obtained results indicated important outcomes, including that the system integrated with PEME is superior in terms of exergetic performance and emissions, whereas the system with AE is superior in terms of economics. The former has a 3.0% greater efficiency and a 3.3% lower emissions at optimal point established by tri-objective optimization, while it has a 9.3% higher levelized product cost.