Municipal Solid Waste Gasification Research Articles

H2-rich syngas produced from steam gasification of municipal solid waste: a modeling approach

H2-rich syngas produced from steam gasification of municipal solid waste: a modeling approach

Modeling the impact of some independent parameters on the syngas characteristics during plasma gasification of municipal solid waste using artificial neural network and stepwise linear regression methods

Thermal plasma gasification is considered as an attractive technology to produce high quality syngas from municipal solid waste (MSW). It is imperative to study the effect of operating parameters on syngas quality and find a practical way to predict syngas characteristics. This paper compiled 112 research cases to develop quantitative models for 8 kinds of syngas characteristics and explored the simultaneous effects of input parameters during the plasma gasification by applying stepwise linear regression (SLR) and artificial neural network (ANN) methods. The SLR model has a higher predictive accuracy than the ANN model for gas yield, volume fraction of CH4 and CO2, as well as mechanical gasification efficiency (MGE), with Rtesting2 = 0.659–0.916. The ANN model demonstrates better performance than the SLR model for low heating value (LHV), dry gas ratio, volume fraction of H2 and CO, with Rtesting2 = 0.807–0.939. According to the importance analysis, flow rates of the work gas-N2, feedstock type, flow rates of the work gas-steam, and input power are the most critical parameters for LHV, gas yield, and volume fraction of CH4 and H2, respectively. Input power and specific energy requirements (SER) are the most important factors affecting volume fractions of H2 (25.7–57.3 vol%) and input power plays a dominant role. The models developed in this study could enhance understanding of plasma gasification and are unique to considering multiple input parameters together.

Pyrolysis and Gasification of Municipal Solid Waste (Msw) Pellets: Effect on Temperature and Hdpe Additive on Gaseous and Solid Products with Special Emphasis on Environmental Aspects

Pyrolysis and Gasification of Municipal Solid Waste (Msw) Pellets: Effect on Temperature and Hdpe Additive on Gaseous and Solid Products with Special Emphasis on Environmental Aspects

Methods for Producing Hydrogen-Rich Syngas in MSW Gasification

Although municipal solid waste (MSW) is a concern in many countries, it may be a highly appealing alternative feedstock for gasification to create sustainable gas fuels. The creation of hydrogen syngas from MSW gasification has received a lot of attention. The employment of a catalyst in the MSW gasification process is known to boost the gasification reactor's performance in producing hydrogen-rich syngas. Furthermore, the co-gasification approach is frequently utilized to increase syngas quality and gasification efficiency. This paper discusses many ways for gasifying MSW for the generation of hydrogen rich syngas. Catalytic gasification, co-gasification, and a modified gasification system are the gasification methods under consideration.

Low-carbon biomass-fueled integrated system for power, methane and methanol production

A novel near zero-CO2 emission system based on gasification of municipal solid waste (MSW) is proposed and analyzed for waste-to-power and power-to-fuel purposes. The integrated system includes an externally fired gas turbine (EFGT), a molten carbonate fuel cell (MCFC), a Rankine cycle and an organic Rankine cycle (ORC), methane and methanol synthesis units and proton exchange membrane electrolyzer (PEME). Three different scenarios for synthetic fuel production (methane-only, methanol-only and dual-production) are investigated considering different operating loads of PEME, as green hydrogen route. For the case that 10% of produced power is consumed by PEME to generate the required hydrogen for methane and methanol synthesis, overall energy and exergy efficiencies are obtained 41 and 36%, respectively. In this case, the system consumes 1012 ton/yr of CO2 to produce 179 ton/yr methane and 393 ton/yr methanol with sustainability index of 1.57. The exergy analysis revealed that the employed EFGT unit is the main source of irreversibility with gasifier as the most exergy destructive component. In addition, the results of sensitivity analysis showed that increasing gas turbine inlet temperature improves both thermodynamic performance of the system and rate of synthetic fuel.

Environmental Impacts of Electricity from Incineration and Gasification: How the LCA Approach Can Affect the Results

Waste-to-energy (WtE) technologies can offer sustainable solutions for waste, which can no more be reused or recycled, such as the part of municipal solid waste (MSW) that is not suitable for recycling processes. This study focused on the environmental consequences of the production of electricity from incineration and gasification of MSW. To this aim, the standardised life cycle assessment (LCA) methodology was used. A life cycle inventory, mainly composed by primary data, is provided. Starting from these data, different highly shared LCA approaches were used to calculate the potential impacts of 1 kWh provided by the two analysed WtE technologies. The different approaches concern the method of accounting for the by-products (through an economic allocation and a system expansion) and the inclusion/exclusion of environmental benefits due to the avoided landfill for the MSW. For each approach, impact-assessment results were calculated with the ReCiPe midpoint (H) method. A comparison was carried out (i) between the results obtained for the same WtE technology but calculated with different approaches and (ii) between the impact results of electricity generated by the two WtE technologies calculated with the same approach. From the study, it emerged that, according to the accounting rules, the impact results can significantly change and, for some impact categories, even lead to opposite conclusions. In the absence of category rules that harmonise the environmental assessments of WtE processes, it is therefore recommended that the development/use/reproduction/comparison of studies focused on the valorisation of waste should be carried out with caution.

Gasification of Densified Biomass (DB) and Municipal Solid Wastes (MSW) Using HTA/SG Technology

The necessity of economical and rational use of natural energy sources caused a rapid development of research on the possibilities of using non-conventional energy resources. Taking the above into account, a new technological process of thermochemical conversion of biomass and communal waste, commonly known as High Temperature Air/Steam Gasification (HTA/SG) and Multi-Staged Enthalpy Extraction Technology (HTAG-MEET), was developed. In relation to traditional techniques of gasification or combustion of hydrocarbon fuels, the presented concept is characterized by higher thermal efficiency of the process, low emission of harmful compounds of carbon, sulfur, nitrogen, dioxins, furans and heavy metals. The use of a high-temperature gasification factor causes an increased thermochemical decomposition of solid fuels, biomass and municipal waste into gaseous fuel (syngas), also with increased hydrogen content and Lower Calorific Value (LCV). In this study, the possibility of using a batch type reactor (countercurrent gasifier) was analyzed for gasification of biomass and municipal waste in terms of energy recovery and environmental protection. The proposed research topic was aimed at examining the possibility of using the thermal utilization of biomass and municipal waste through their high-temperature decomposition in the presence of air, a mixture of air and steam. The main goals of the research were achieved during the implementation of several parallel stages of the schedule, which included, primarily: (a) study of the possibility of using thermal utilization of biomass and municipal waste through their high-temperature gasification in the presence of air or a mixture of air and steam and, secondary (b) analytical and numerical modeling of high-temperature gasification of biomass and municipal waste with the use of ANSYS CFD Fluent 6.3 software. Selected results of the experimental and numerical studies are properly presented. The higher temperature gasification concept shows the capability of this technology for maximizing the gaseous product yield in an up-draft fixed bed gasifier. It was also observed that at a high temperature, steam addition contributed to the thermal conversion of biofuels to gas with higher production of hydrogen.

Effect of the Colombian Renewable Energy Law on the Levelized Cost of a Substitute Gaseous Fuel Produced from MSW Gasification

Colombian municipal solid waste (MSW) production trends indicate that sanitary emergencies could occur in the largest cities of the country by 2030 because of the end of their landfills’ useful life. In this work, the energy recovery from different MSW through the updraft plasma gasification process to produce syngas as a substitute gaseous fuel was assessed from an economic viewpoint. The study was carried out using the results of an implemented model under a thermochemical approach using Aspen Plus. The economic assessment was conducted using the levelized cost of syngas production (LCOS), which was regarded as an economic indicator that considers tax incentives in the context of the Colombian renewable energy regulations (Law 715 of 2014). The combination between operational conditions (air flow and plasma temperature) allowed finding the maximum efficiency by means of a sensitivity analysis. The maximum efficiency ranged from 79,22 to 83,46%, highlighting the flexibility of the plasma gasification process to treat MSW. The lowest levelized syngas production cost reached with tax incentives varied from 13,19 to 22,95 ¢US$/kWh. Therefore, a waste disposal charge was proposed to make these projects feasible, which must range between 11,25 and 23,56 ¢US$/kWh (123-259 US$/t)

Feasibility of non-thermal plasma gasification for a waste-to-energy power plant

The feasibility of non-thermal plasma gasification of municipal solid waste (MSW) was investigated by modeling waste-to-energy (WtE) power plants, such as an incineration power-plant cycle and integrated plasma gasification combined cycles (IPGCCs) with thermal and non-thermal plasma gasification. The energy analysis delineated operation conditions of non-thermal plasma gasification, which would improve the energy efficiency of the existing IPGCCs. The sensitivity analysis of the energy efficiency showed that cold gas efficiency (CGE), which is the ratio of the heating value of the syngas to the heating value of MSW, is more important than the power consumption of the plasma source for the energy efficiency. From the exergy analysis, it was revealed that the largest exergy loss of the IPGCC was at the plasma gasification, regardless of the type of plasma source. The total exergy loss of IPGCC could be reduced by adapting non-thermal plasma gasification if a similar level of CGE to thermal plasma gasification is achieved. Therefore, non-thermal plasma gasification should attain a similar CGE level of thermal plasma gasification along with reduced power consumption. Then, using non-thermal plasma gasification instead of thermal plasma gasification for IPGCC would become feasible.

Effect of calcium-based sorbents on the reduction of chlorinated contaminants during municipal solid waste thermal treatment.

Chlorinated contaminants are a cause of significant concern in the development of municipal solid waste (MSW) thermal treatment techniques. This study investigates the efficacy of two calcium (Ca)-based in-furnace additives, calcium oxide (CaO), and calcined dolomite (CD), at reducing the levels of chlorinated contaminants during MSW thermal treatment. The results reveal that Ca-based additives could effectively reduce the chlorine (Cl) content by more than 76.8% and 37.3% in the gas and tar phases, respectively. The total concentration and the international total equivalent (I-TEQ) value of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) were significantly higher under the incineration condition than pyrolysis and gasification conditions. Adding CaO could reduce the total concentration and the I-TEQ value of PCDD/Fs by more than 43.4% and 36.7%, respectively. The reduction effect on PCDD/Fs was more significant in the gaseous phase and the tar phase than the solid phase. CD was more effective than CaO at reducing the chlorinated contaminants, including hydrogen chloride, Cl in the tar phase, and PCDD/Fs. Thus, adding Ca-based sorbents in the furnace during MSW pyrolysis and gasification can effectively reduce PCDD/Fs generation. Based on the experimental results, the mechanism of Ca-based sorbents on the high-temperature homogeneous reaction of PCDD/Fs formation was analysed.

Techno-Economic Analysis of Municipal Solid Waste Gasification System for Electric Generation, Case Study: City at Central Java

Municipal Solid Waste (MSW) management is a problem in Indonesia because of the rapidly increasing volume and limited land. The Waste to Energy (WTE) concept is a concept that will be carried out for municipal solid waste management where the solid waste will be managed into electrical energy and reduce the volume of solid waste significantly by building a Gasification – engine system, one of which in Surakarta Central Java. MSW management infrastructure in one of the infrastructures that can be cooperated with the scheme of Public Private Partnership (PPP) in the form of investment project with a 20-years concession period and the BOOT (Build, Own, Operate, and Transfer) method. Downdraft Fixed bed gasification from Ankur scientific Energy Technologies Pvt, Ltd used for electric generation. Around 300 tons/day new municipal solid waste and 700 tons/day old waste as fuel resources. Potential power generating capacity of 8 MW (Gross) with an investment cost of Rp. 367.622.450.000. Techno economic analysis used the Capital Budgeting method. Result calculations obtained NPV is positive, IRR on project of 14,5%. Operation of MSW gasification system can reduce CH4 emission with equivalent 85.126,86 tCO2/year.

Scaling-up defect-free asymmetric hollow fiber membranes to produce oxygen-enriched gas for integration into municipal solid waste gasification process

Municipal solid waste (MSW) gasification is an attractive waste-to-energy (WTE) technology with promise for future solid waste management, owing to the production of syngas which can be used as an alternative energy resource. However, quality of produced syngas is not meeting expectation. One promising solution is to use oxygen-enriched gas (OEG) to elevate produced syngas quality but producing OEG is costly. Herein, we demonstrated an asymmetric defect-free hollow fiber membrane made up of Matrimid® 5218 polyimide for scaling-up to 2-inch membrane modules. Our modules have an effective surface area up to 2.6 m2 with a packing density of up to 44% to produce OEG of 45% O2 purity. The 2-inch membrane module was integrated into a lab-scale gasification process to produce syngas using refuse derived fuel (RDF) generated from MSWs collected from the university campus. Prior to this, the lab-scale gasification was first optimized by tuning the gasification temperature, O2 purity and equivalence ratio (ER). Then, MSW gasification using membrane-based OEG was carried out, and compared against air gasification and synthetic OEG of the same O2 purity. Our results showed that, at O2 purity of 45%, gasification temperature of 900 °C and ER of 0.15, the quality of produced syngas was elevated with a lower heating value (LHV) of 9.15 MJ/m3 and H2/CO ratio of 1.43, which was substantially higher than air gasification with LHV and H2/CO ratio reported at 5.38 MJ/m3 and 0.81, respectively. Gasification results for membrane-based OEG and synthetic OEG were also comparable, while process simulation evidence suggested that membrane-based separation was at least 2-fold less energy-intensive than cryogenic distillation and pressure swing adsorption. Overall, this proof-of-concept successfully demonstrates the viability and competitiveness of membrane process for producing OEG at medium O2 purity (i.e., 40–50%) to support MSW gasification for WTE conversion.

High temperature slagging gasification of municipal solid waste with biomass charcoal as a greener auxiliary fuel

During high temperature slagging gasification of municipal solid waste (MSW), coal coke is typically used as an auxiliary fuel to maintain the high temperature in the gasifier and convert ashes into slag. Herein, biomass charcoal was utilized as a greener and more sustainable auxiliary fuel to replace the coal coke during stable and continuous gasification of MSW. Several monitoring characteristics were assessed, like operating conditions of the gasifier, influence of local MSW properties generated in Singapore, environmental impacts, and main by-products (slag, fly ash and metals). The performance data revealed that the replacement of coal coke with biomass charcoal provided significant environmental benefits. The use of biomass charcoal resulted in 78% less SO2 emissions, and 22% less generated fly ash because the lower sulfur content in biomass charcoal resulted in a 32% reduced use of sorbent for flue gas treatment. Furthermore, there was clear evidence of a 22% carbon footprint reduction due to replacing fossil fuel as auxiliary fuel. In addition, the slag characteristics demonstrated lower heavy metals leaching as compared to the incineration bottom ash generated from the conventional MSW incineration plant suggesting its great potential in the application as clean and green waste-derived material in the construction industry.

Thermodynamic modeling of a power and hydrogen generation system driven by municipal solid waste gasification

Thermodynamic modeling of a power and hydrogen generation system driven by municipal solid waste gasification

Hydrogen-rich syngas from wet municipal solid waste gasification using Ni/Waste marble powder catalyst promoted by transition metals.

Gasification of wet municipal solid waste (MSW) coupled with in-situ CO2 capture is an attractive option for MSW disposal, allowing chemical and energy recovery. In this study, the Ni-CaO based catalysts were prepared with waste marble powder (WMP) as an alternative to CaO and promoted by different transition metals (i.e., Fe, Cu, Co and Zn). The bimetallic catalysts were prepared by the impregnation method and characterized by different analytical techniques. The catalyst performance for wet MSW gasification was evaluated in a fixed-bed reactor at optimized conditions (850°C and 50% moisture content of MSW). The results revealed that the addition of Ni-WMP catalyst greatly enhanced the dry gas yield (DGY), H2 yield, carbon conversion efficiency (CCE) and reduced the tar content from 0.73 to 1.16N.m3/kg, 212 to 509mL/g, 61.70% to 76.40% and 9.11 to 3.9wt%, respectively, compared to without catalyst. In contrast to the Ni-WMP catalyst, the transition metal promoted catalysts showed higher catalytic activity towards H2 yield (549-629mL/g), DGY (1.19-1.30N.m3/kg), and lower tar content (3.45-2.93wt%). The results revealed that Co promoted bimetallic catalyst performed better than Fe, Cu and Zn promoted catalysts. The tar content produced was also analyzed via GC-MS (gas chromatography-mass spectrometry) to understand the effect of different catalysts on tar composition. According to experimental results, the bimetallic promoted catalysts can be ranked as Ni-Co-WMP>Ni-Cu-WMP>Ni-Fe-WMP>Ni-Zn-WMP based on H2 yield and tar removal.

Selected Environmental Aspects of Gasification and Co-Gasification of Various Types of Waste

The process of gasification of carbonaceous fuels is a technology with a long-standing practice. In recent years, the technology has been extensively developing to produce energy or chemicals on the basis of obtained gas. Studies focused on the improvement of the gasification process aims at developing the process by increasing environmental safety, the efficiency and the possibilities to utilize various types of alternative fuels (post-consumer waste, various types of biomass waste, by-products and post-process residues, sewage sludge) independently or by co-gasification with coal. The choice of the gas purification system, the process operating parameters and introducing the necessary modifications to the existing technologies are essential steps while processing these kinds of feedstock, with regard to their individual characteristics. This paper discusses selected environmental aspects of the gasification and co-gasification of municipal solid waste, sewage sludge, various types of biomass waste and post-process residues. Selected alternative fuels are also characterized, focusing on the influence of their presence in the feedstock in terms of production and the emission of polychlorinated organic compounds, tars, heavy metals and toxic elements.

Novel two-stage fluidized bed-plasma gasification integrated with SOFC and chemical looping combustion for the high efficiency power generation from MSW: A thermodynamic investigation

A novel municipal solid waste (MSW)-based power generation system was proposed in this study, which consists of a bubbling fluidized-bed (BFB)-plasma gasification unit, a high-temperature solid oxide fuel cell (SOFC), a chemical looping combustion (CLC) unit and a heat recovery unit. Process simulation was conducted using Aspen Plus™ and validated by literature data. The energetic and exergetic assessment of the proposed system showed that the net electrical efficiency and exergy efficiency reached 40.9% and 36.1%, respectively with 99.3% of carbon dioxide being captured. It was found that the largest exergy destruction took place in the BFB-Plasma gasification unit (476.5 kW) and accounted for 33.6% of the total exergy destruction, followed by the SOFC (219.1 kW) and then CLC (208.6 kW). Moreover, the effects of key variables, such as steam to fuel ratio (STFR), fuel utilization factor (Uf), current density and air reactor operating temperature, etc., on system performance were carried out and revealed that the system efficiency could be optimized under STFR = 0.5, Uf = 0.8 and air reactor operating temperature of 1000 °C. Furthermore, the proposed process demonstrated more than 14% improvement in net electrical efficiency in comparison with other MSW incineration and/or gasification to power processes.

Treatment and valorization of municipal solid waste gasification effluent through a combined advanced oxidation – microalgal phytoremediation approach

Liquid effluents generated during the gasification process of municipal solid wastes (MSW) represent highly heterogenous and recalcitrant substrates, and thus require energy-intensive treatments prior to their discharge into the environment. However, these streams represent untapped carbon sources which can be converted, under the right conditions, to platform molecules, decreasing thus the elevated costs of current mitigation approaches. Thus, the present study describes a novel two-step chemical and biological effluent treatment process which co-generates microalgal biomass containing valuable functional components. The detoxification potential of ozone, ultrasonication and a combination of both of these advanced oxidation processes (AOPs) were initially evaluated using wastewater generated from scrubbing primary syngas produced from the gasification of MSW. The pretreated effluents were subsequently used to cultivate Chlorella vulgaris microalgae under various illumination (light/dark cycles of 24h/0h, 12h/12h and 0h/24h) and nutrient (supplementation of yeast extract) regimes, in order to assess their potential to further convert the remaining carbon into value-added functional biomolecules, such as photosynthetic pigments. The use of ozone, either individually or combined with ultrasounds, showed the best performances for the substrate detoxification prior to the biological treatment step. It was determined that 20 min of oxidative reaction using ozone coupled with ultrasounds was sufficient to degrade up to 70% of the total phenol compounds, 64% of the COD, and 75% of the color initially present in the gasification wastewater. The further microalgal phytoremediation and conversion experiments showed that 12 h of illumination per day, together with 0.5 g/L of yeast extract, generated the highest microalgae growth rate (0.29 d−1), biomass productivity (244 mg/L/d), photosynthetic pigment accumulation (12.0 and 4.5 mg/L of total chlorophyll and carotenoids, respectively) as well as total carbon removal (57 %). Therefore, the combination of AOPs with mixotrophic cultivation of C. vulgaris demonstrates for the first time an alternative to current treatment strategies of highly-recalcitrant industrial wastewaters, which includes the further valorization of the carbon available in these streams.

Thermodynamic Assessment of a Gas Turbine System Combined with A Solid Oxide Fuel Cell Powered by Synthetic Gas from Municipal Solid Waste

In this work, a detailed thermodynamic analysis is performed on a solid oxide fuel cell-gas turbine combined system. The fuel input to the fuel cell is the synthetic gas produced from the gasification of municipal solid waste. The efficiency and output power of the system are calculated and the system is analyzed for its performance by variation of parameters which includes compression ratio, fuel utilization factor and current density. The work is done based on the Municipal solid waste generated in Indian cities. Destruction of exergy is calculated from exergy analysis. System is modelled using flow sheeting program Cycle Tempo®. Components contributing to major exergy destruction are combustor and fuel cell. Energy efficiency of 44.5%, exergy efficiency of 39.2% and a power output of 170 kW is obtained in this system. This CHP system is very much acceptable for restaurants, shopping complex and other small-scale applications where power requirement is less.

Advanced technology of municipal solid waste conversion for a circular economy

One of the most important environmental problems of the big urban areas is represented by the large volume of waste resulted from different human activities. In the last decades, different technologies have been developed to resolve this significant issue, and the most representative is the conversion of municipal solid waste (MSW) in different types of by-products. The first part of this paper presents the current state of plasma conversion technology that can be used for processing waste, and also, its potential in the construction sector which could be taken advantage of the by-products (syngas and slag) resulted from the plasma gasification of municipal solid waste (MSW), to enhance energy-efficiency in this domain. In the second part of the paper, there are analyzed different technologies for managing and processing municipal solid waste (MSW), which can be used nowadays, and the parameters, related to the costs, the period of use, the energy consumption and the environmental impact. All these aspects are compared with those of plasma conversion technology. The plasma conversion system can be commercialized successfully, and its costs can be reduced by generating income in the form of by-products and added-value in producing performant products in a circular economy.