Clean Syngas Research Articles

Gasification of Municipal Solid Waste: Thermodynamic Equilibrium Analysis Using Gibbs Energy Minimization Method and CFD Simulation of a Downdraft Gasifier

Millions of tons of municipal solid waste (MSW) are generated annually, posing dramatic threats to our environment. To reduce its environmental impact, MSW can be segregated and thermochemically converted into clean syngas (CO and H2) fuel via gasification process. The feasibility of Gasification of MSW depends on its composition and quantity. In this work, assessment of the gasification metric of MSW is conducted under steam (H2O) as gasification moderator in a pilot scale 20kW gasifier. The characteristic of local MSW are experimentally determined using Flash 2000 organic analyzer (CHNS-O), the thermo-gravimetric analyzer (TGA) and bomb calorimeter following ASTM standards and arriving to molar formula of MSW. A thermodynamic equilibrium model based on Gibbs energy minimization method is used for the steam gasification of MSW to assess the composition of syngas. Using the baseline operating condition from the thermodynamic equilibrium model, a reactive high fidelity numerical model of a downdraft gasifier is developed to gain more fidelity. Result of gasification efficiency of thermodynamic model is 64% while reactive model gives 7% additional efficiency. Nonetheless, the stipulated efficiency and the high-quality syngas produced via the steam gasification of MSW suggest the viability of the process scale up.

High-Purity and Clean Syngas and Hydrogen Production From Two-Step CH4 Reforming and H2O Splitting Through Isothermal Ceria Redox Cycle Using Concentrated Sunlight

The thermochemical conversion of methane (CH 4) and water (H 2 O) to syngas and hydrogen, via chemical looping using concentrated sunlight as a sustainable source of process heat, attracts considerable attention. It is likewise a means of storing intermittent solar energy into chemical fuels. In this study, solar chemical looping reforming of CH 4 and H 2 O splitting over non-stoichiometric ceria (CeO 2 /CeO 2−δ) redox cycle were experimentally investigated in a volumetric solar reactor prototype. The cycle consists of (i) the endothermic partial oxidation of CH 4 and the simultaneous reduction of ceria and (ii) the subsequent exothermic splitting of H 2 O and the simultaneous oxidation of the reduced ceria under isothermal operation at ∼1,000 • C, enabling the elimination of sensible heat losses as compared to non-isothermal thermochemical cycles. Ceria-based reticulated porous ceramics with different sintering temperatures (1,000 and 1,400 • C) were employed as oxygen carriers and tested with different methane flow rates (0.1-0.4 NL/min) and methane concentrations (50 and 100%). The impacts of operating conditions on the foam-averaged oxygen non-stoichiometry (reduction extent, δ), syngas yield, methane conversion, solar-to-fuel energy conversion efficiency as well as the effects of transient solar conditions were demonstrated and emphasized. As a result, clean syngas was successfully produced with H 2 /CO ratios approaching 2 during the first reduction step, while high-purity H 2 was subsequently generated during the oxidation step. Increasing methane flow rate and CH 4 concentration promoted syngas yields up to 8.51 mmol/g CeO 2 and δ up to 0.38, at the expense of enhanced methane cracking reaction and reduced CH 4 conversion. Solar-to-fuel energy conversion efficiency, namely, the ratio of the calorific value of produced syngas to the total energy input (solar power and calorific value of converted methane), and CH 4 conversion were achieved in the range of 2.9-5.6% and 40.1-68.5%, respectively.

Catalytic tar conversion and the prospective use of iron-based catalyst in the future development of biomass gasification: a review

Biomass is a promising renewable energy source which is available globally, mostly in developing countries where access to clean and affordable energy is a critical problem. Biomass gasification is an interesting technology that can convert biomasses to a more versatile fuel known as syngas, the energy which can substitute conventional fossil fuels in the future. Syngas can amenably be combusted to produce power and heat as well as a feedstock for synthesis of chemicals and other fuels. The biomass gasification is facing severe operational challenges, one of the problems being tar formation and its removal techniques. Tar condenses at reduced temperature, thus causing blockage in the downstream equipment such as compressors and engines. Many studies have considered syngas cleaning by physical removal and thermal cracking unsuitable as they need downstream processing of scrub liquor and utilizes a part of the produced gas in maintaining the thermal cracking temperature, respectively. The utilization of catalysts has been an interesting focus; however, it has not yet been fruitful as many of the developed catalysts deactivate rapidly, and they are expensive or toxic. The motives of the current study are to review tar formation characteristics and trends on catalytic conversion. In addition, the study elucidates the fascinating behaviour of metallic and oxides of the iron-based catalyst under different syngas composition (oxidizing and reducing environments). The behaviours of the iron-based catalyst indicate its fundamental role in developing a catalyst for tar cracking with respect to less toxic, inexpensive, abundant, and regenerable alternatives.

Environmental Impact and Environmental Cost Assessment of Methanol Production from wood biomass

Increasing demand for biofuel production and global competition for the use of natural resources are key factors in finding new and environmentally safe routes for methanol production. In the present study, life cycle assessment was used to analyse the potential environmental impact and environmental cost of a novel methanol production process from wood compared to a conventional processes. Both the novel and the conventional process were divided into three stages: pre-treatment, gasification, and syngas cleaning and methanol synthesis. The environmental impacts were assessed and compared using Simapro 9 (ecoinvent 3.5 database) and the ReCiPe 2016 (World-H) midpoint method. The results, expressed per tonne methanol, showed that the impact categories of global warming potential (GWP) and marine ecotoxicity potential were lower in the novel process in comparison to the conventional process (48.2 kg CO2 eq. vs. 63.1 kg CO2 eq., and 4.55 kg 1,4-DCB vs. 6.35 kg 1,4-DCB respectively). However, the novel process had a higher environmental impact in the pre-treatment stage. The results of the sensitivity analysis showed that the GWP of the novel process increased from 48.2 kg CO2 eq. to 216 kg CO2 eq. due to the replacement of Na2CO3 by K2CO3. The human toxicity impact categories showed significant impact on environmental cost. These findings will help relevant industries to reduce their environmental impact and improve the production efficiency of methanol from wood.

Syngas Production, Clean-Up and Wastewater Management in a Demo-Scale Fixed-Bed Updraft Biomass Gasification Unit

This paper presents the experimental development at demonstration scale of an integrated gasification system fed with wood chips. The unit is based on a fixed-bed, updraft and air-blown gasifier—with a nominal capacity of 5 MWth—equipped with a wet scrubber for syngas clean-up and an integrated chemical and physical wastewater management system. Gasification performance, syngas composition and temperature profile are presented for the optimal operating conditions and with reference to two kinds of biomass used as primary fuels, i.e., stone pine and eucalyptus from local forests (combined heat and power generation from this kind of fuel represents a good opportunity to exploit distributed generation systems that can be part of a new energy paradigm in the framework of the circular economy). The gasification unit is characterised by a high efficiency (about 79–80%) and an operation stability during each test. Particular attention has been paid to the optimisation of an integrated double stage wastewater management system—which includes an oil skimmer and an activated carbon adsorption filter—designed to minimise both liquid residues and water make-up. The possibility to recycle part of the separated oil and used activated carbon to the gasifier has been also evaluated.

High-Temperature, Dry Scrubbing of Syngas with Use of Mineral Sorbents and Ceramic Rigid Filters

In this research, the idea of multicomponent, one-vessel cleaning of syngas through simultaneous dedusting and adsorption is described. Data presented were obtained with the use of a pilot-scale 60 kWth fixed-bed GazEla reactor, coupled with a dry gas cleaning unit where mineral sorbents are injected into raw syngas at 500–650 °C, before dedusting at ceramic filters. The research primarily presents results of the application of four calcined sorbents, i.e., chalk (CaO), dolomite (MgO–CaO), halloysite (AlO–MgO–FeO), and kaolinite (AlO–MgO) for high-temperature (HT) adsorption of impurities contained in syngas from gasification of biomass. An emphasis on data regarding the stability of the filtration process is provided since the addition of coating and co-filtering materials is often necessary for keeping the filtration of syngas stable, in industrial applications.

Development and characterization of innovative carbon-based waste ashes/epoxy composites

In this study, carbon based ashes were produced by the wooden biomass pyro-gasification plant CMD ECO20. CMD ECO20 is a micro-scale combined heat and power system powered with biomass, under development by the Italian company Costruzioni Motori Diesel (C.M.D) S.p.A. It is an integrated system combining a downdraft gasifier, a spark ignition internal combustion engine, an electric generator and syngas cleaning devices, and it is able to produce electric and thermal power up to 20 kWe and 40 kWth.Three different types of fillers were produced from ashes starting from innovative green waste: the first type (MA) was obtained by mortar milling, while the second (DBA) and the third (WBA) one were produced by dry and wet ball milling, respectively. MA, DBA e WBA fillers were characterized by several techniques including Scanning Electron Microscopy (SEM), Multi-angle light scattering (MALS) and Energy Dispersive X-ray (EDX) Spectrometry. Each filler was added to epoxy resin EC01 in an amount equal to 1, 3, 5 and 10 wt%. The curing agent (22phr) was added to the resin that was cured for 1 h at 60 °C and 2 h at 150 °C. Finally, the flexural properties and the glass transition temperature of the cured neat epoxy and ashes filled epoxy composites were measured.The elastic modulus of the epoxy resin containing an amount of fillers from 1 to 10 wt% is higher in comparison to that of the neat epoxy. The flexural strength of the epoxy resin containing an amount of DBA of 3 wt% is also higher than that of the neat epoxy.

Syngas cleaning for coal to methanol demo plant – H2S and COS removal

Syngas cleaning, especially the removal of COS and H2S, is a crucial step in the production of valuable chemicals from coal. As a part of the Tuncbilek Coal to Methanol project, a gas cleaning demo plant has been built. The aim of this paper is to disseminate the experience gained from these demo plant experiments concerning the performance of the gasifier and syngas cleaning demo-plant, especially about the removal of sulfur compounds. Additionally, some practical recommendations regarding the design and operation of such demo plants are given. The design-basis for the demo plant was a gas stream of 450 m3/h (at STP) containing 4,000 ppmv H2S and 2,000 ppmv COS. The performance target was to reduce H2S and COS concentrations to less than one ppmv each. The gas cleaning process consisted of a particulate filter, COS hydrolysis reactors, caustic scrubbers, H2S guard beds and heat exchangers. Two demo plant runs were conducted, and Tuncbilek lignite was gasified in the 6 ton/day (coal feeding capacity) entrained flow gasifier. The gasifier produced syngases with lower heating values of 7.64 and 8.86 MJ/m3 (at STP), and cold gas efficiencies of 71 and 81% were achieved. The H2S and COS content of the successful run were 3,300 ppmv and 550 ppmv, respectively. At the exit of the gas cleaning demo plant, a concentration of 0.12 ppmv for H2S and 0.72 ppmv for COS were measured. Consequently, it was concluded that the performance of the gas cleaning demo plant was satisfactory for methanol production.

Evaluation of sorbents for high temperature removal of tars, hydrogen sulphide, hydrogen chloride and ammonia from biomass-derived syngas by using Aspen Plus

Biomass gasification is a promising technology to produce secondary fuels or heat and power, offering considerable advantages over fossil fuels. An important aspect in the usage of producer gas is the removal of harmful contaminants from the raw syngas. Thus, the object of this study is the development of a simulation model for a gasifier including gas clean-up, for which a fluidized-bed gasifier for biomass-derived syngas production was considered, based on a quasi-equilibrium approach through Gibbs free energy minimisation, and including an innovative hot gas cleaning, constituted by a combination of catalyst sorbents inside the gasification reactor, catalysts in the freeboard and subsequent sorbent reactors, by using Aspen Plus software. The gas cleaning chain simulates the raw syngas clean-up for several organic and inorganic contaminants, i.e. toluene, benzene, naphthalene, hydrogen sulphide, hydrogen chloride and ammonia. The tar and inorganic contaminants final values achieved are under 1 g/Nm3 and 1 ppm respectively.

Fluidised Bed Reactors for the Thermochemical Conversion of Biomass and Waste

The growing population and economic development globally has led to increasing resource consumption and waste generation. This has generated concern at local, national and international levels on environmental issues including air quality, resource scarcity, waste management (including plastics) and global warming. The resulting antipathy towards fossil fuels and waste landfilling has spurred the demand for alternative bioenergy and biofuels production methods, making use of abundant biomass and waste feedstock. Although not new concepts, there has been renewed impetus recently to develop advanced thermochemical processes such as pyrolysis and gasification to treat biomass and municipal solid waste (including refuse-derived fuel therefrom). This is because these processes have the potential to add value to cheap and abundant materials by converting them into advanced biofuels and chemicals. The work presented in this paper is concerned principally with the technical analysis and review of new-generation, state-of-the-art systems based on fluidised bed reactors operated with biomass and solid waste. A comprehensive assessment of fluidised bed reactor types and operations is considered, with particular attention given to those processes aimed at the production of clean syngas for the subsequent synthesis of high-value products, including bio-hydrogen, synthetic natural gas (SNG), and liquid fuels.

Process Optimization of Wood Particles Microwave Pyrolysis with Combined Production of Bio-Oil and Syngas.

Microwave is an alternative method which can rapidly pyrolyze biomass by thermal treating, and produce clean syngas and bio-oil products. In this research, the wood particles microwave pyrolysis process was proposed for preparing bio-oil and syngas production. The wood particles were first pyrolyzed by microwave reactor in the process, and then the bio-oil products were separated by cyclone separator and multi-phase separator, syngas products were prepared by steam reforming reactor and absorption tower. Kinetics for larch microwave thermogravimetry reactions were proposed and correlated with lab-scale experiments; the microwave pyrolysis process was simulated in Aspen HYSYS, and the results showed that when pyrolysis reaction temperature and microwave power were 900℃ and 2.0 kW respectively, the maximum bio-oil and syngas production can be achieved. The H2/CO and CO2 content in syngas which can be used in chemical processes such as Fischer-Tropsch synthesis, can be controlled by the molar ratio function of steam and pyrolysis gas.

Exergy analysis of the multi-stage slag waste heat recovery system

Based on the black-box model, this paper analyzed the multi-stage slag waste heat recovery system. The exergy efficiency, the exergy loss coefficient and the exergy loss rate were adopted as evaluation indexes to investigate the energy consumption and the weakness of the system. Meanwhile, the performance of waste heat recovery was analyzed by comparing the comprehensive exergy efficiency between the system and other conventional waste heat recovery methods. The results showed that the comprehensive exergy efficiency of the system reached 75.75%, which was much higher than other methods, and the weakness of the system was the subsystem of waste heat boiler. In general, the system recovered the slag waste heat effectively and converted coal to clean syngas through gasification reaction, which had incredible potential in energy saving, emission reduction and consumption reduction.

Solar thermochemical conversion of carbonaceous materials into syngas by Co-Gasification

Transitioning from fossil fuel based energy sources to more viable and alternative renewable energy sources requires intermediary methods that bridge the gap between existing technology and newer innovative renewable technologies. The objective here is to provide for a more reliable power source that can extend its reach to even the remotest rural areas.This paper provides a numerical method that tests the possibility of coupling a solar energy heat source with a co-gasification process dependent on biomass and coal for producing syngas throughout all hours of the day. A hybrid reactor that is modeled by the Monte Carlo ray tracing method for its geometric and maximum temperature is obtained in the cavity. Numerous factors were accounted for that determined the performance of the reaction in the indirectly irradiated fluidized bed solar reactor. The co-gasification modeling calculation utilized 50% lignite coal and 50% olive pomace with oxygen and steam to estimate the gasification performance parameters.The co-gasification process, using solar energy as the heat source, had in fact shown to produce clean syngas. Oxygen and steam were mixed to ensure the continuous production of syngas, as oxygen was critical in enabling some of the feedstock to be combusted during the low/absence of solar energy. The stoichiometric equilibrium model was also used to estimate the gasification performance and the effect of the gasifying agent ratios. The results also indicate that the effect of variation of O2: C ratio is an important factor that affects both the bed temperature and the carbon conversion, whilst the negative impact of combustion was apparent on the H2:CO, cold gas ratio, solar-fuel efficiency, and CO2 production. Changing H2O:C ratio was less apparent but still significant in the co-gasification process.

Study on kinetics and bio-oil production from rice husk, rice straw, bamboo, sugarcane bagasse and neem bark in a fixed-bed pyrolysis process

In this study, rice husk, rice straw, bamboo, sugarcane bagasse, and neem bark were pyrolyzed in a fixed-bed pyrolyzer to examine the influence of operating conditions, such as the temperature of the pyrolysis process, residence time of volatiles, and reactor length, on the yield of bio-oil and individual gas components. The temperature of pyrolysis was varied from 350 to 650 °C at increments of 50 °C, and the length of the reactor was varied from 45 to 60 cm at intervals of 5 cm. The maximum bio-oil production of 46.93 wt% and the pyrolysis char of 26.2 wt% was obtained for bamboo at 450 °C. The highest amount of clean syngas (carbon monoxide and hydrogen) was produced for neem bark (52.61 vol%). The gaussian distributed activation energy model data exhibited a superior fit with the experimental data compared with the single-reaction model for bio-oil and all other individual component gases. The presence of C–H, CC, alcohols and phenolic compounds indicated that the bio-oil obtained from all the biomass species could potentially be used as fuel. The steady-state mass and energy balances for the entire pyrolysis plant were obtained using the Aspen Plus simulation.

(Invited) Design Consideration of an IGFC System with CO2 Capture

Due to vast coal reserve and its lower cost, integrated Gasification Combined Cycle (IGCC) and Integrated Gasification Fuel Cell (IGFC) power generation system are being developed to use coal effectively and reduce air pollution. Compared to IGCC, the advantage of IGFC is higher efficiency and lower overall cost, especially pressurized system. An IGFC system is being developed using syngas as fuel with CO2 capture at National Institute of Clean Low-Carbon Energy (NICE). In the system, the high temperature solid oxide fuel cell (SOFC) stacks are used to convert fuel to electricity. The system design principles, syngas composition and SOFC stack performance effect on system efficiency, and the system cost will be discussed, estimated, and analyzed based on the model established. The method of CO2 capture will also be discussed and recommended based on experimental data. There is variety of impurities in syngas, such as sulfur, PH3, Siloxane, chlorine, Arsine, etc, which may poison SOFC anode and significantly affect system performance. Syngas cleaning is needed before powering the stack using syngas. Besides, there is significant amount of CO2 in initial syngas which will dilute flammable H2 concentration which may affect both power generation and the efficiency of the system, which eventually resulted in higher cost. Two syngas cleaning methods were evaluated and recommendation was made based on experimental results. Syngas composition may vary based on the cleaning method to be used. The CO in syngas has two potential negative effects on SOFC operation. First, the Boudouard reaction is of concern in the temperature range from 500 to 600oC when CO can dissociate into C and CO2 (equation 1), which is called carbon coking. The method to prevent carbon coking was discussed. Second, if dry syngas is used as fuel, the water-gas shift reaction (equation 2) may occur in SOFC stack with the accumulation of water steam formation from electrochemical reaction, which is exothermic. The heat release from water-gas shift reaction would increase temperature difference between stack inlet and outlet which make it difficult to manage stack temperature to achieve optimized performance. SOFC stack electrical efficiency was analyzed with different fuel compositions and under different designed operation conditions, such as anode recycle ratio, using the model established. CO ↔ CO2 + C (1) CO + H2O ↔ H2 + CO2 (2) In order to capture CO2 from exhaust fuel gas, CO2 has to be concentrated higher than 98% first in the tail gas. Technical approaches were identified. Small scale matrix tests show promising results to meet expectation. Fabrication of scale-up testing equipment for technology verification is in process.

Syngas for biorefineries from thermochemical gasification of lignocellulosic fuels and residues\u20145\xa0years\u2019 experience with an advanced dual fluidized bed gasifier design

In many processes proposed for biorefineries, recycling procedures, and industrial or agricultural production processes, residue is generated which could be further transformed by thermochemical conversion via gasification. The technology of dual fluidized bed steam gasification is capable of producing a valuable product gas out of such residue. The generated nitrogen-free product gas can be used for heat and power production and is suitable for separating gases (e.g. hydrogen). However, if the product gas is cleaned, its use as syngas is more beneficial for manufacturing renewable chemical substances, like synthetic natural gas, methanol, Fischer–Tropsch liquids, or mixed alcohols. This paper presents the results of experimental research from gasification test runs of different biogenic fuels, carried out with an advanced 100 kW pilot plant over the last 5 years at TU Wien. The focus is to provide an overview of measured results validated by mass and energy balances and to present key calculated performance indicating key figures of the test runs. In this way, the influence of various operational parameters and the composition of the product gas are evaluated. The presented results form the basis for the proper design of suitable gas-cleaning equipment. Subsequently, the clean syngas is available for several synthesis applications in future biorefineries.

Biomass-derived syngas production via gasification process and its catalytic conversion into fuels by Fischer Tropsch synthesis: A review

The Fischer–Tropsch (FT) synthesis has been investigated over decades as an alternative route to obtain synthetic fuels from synthesis gas. FT is a high-performance synthesis based on metallic catalysis, mainly using ruthenium, cobalt and iron catalysts, which converts syngas in hydrocarbons and chemical precursors. This work presents a review on the aspects of the syngas production from biomass gasification and its subsequent conversion into fuels through the Fischer-Tropsch synthesis. The usage of biomass, including lignocellulosic residues, as a raw material in the gasification process. Biosyngas is highlighted as a synthetic fuel source to replace nonrenewable, conventional fossil fuels. Lignocellulosic material must be considered a low-cost feedstock to the liquid biofuel production on a large scale. Studies on syngas cleaning to attain the purity required by the FT process is revised. Recent understanding of reaction kinetics and thermodynamics has contributed to increasing the FT performance and economic viability. This paper includes also the debate on main catalysts, industrial process requirements, and chemical reaction kinetics and mechanisms of Fischer–Tropsch synthesis.

Syngas production from sugarcane leftover gasification integrated with absorption process for green liquid production

The aim of research is to present favorable operating conditions for the clean syngas production from sugarcane leftover through the gasification process by using AspenPlus™ software. In order to obtain the suitable syngas for liquid fuel production, this process should be integrated with gas cleaning. The simulation was performed by comparing three gasifying agents, i.e., steam, air, and steam-air. To find favorable operating conditions that provide the highest syngas molar flow rate, the effect of operating conditions in gasifier was also examined. In addition, the possibility of syngas production operated under a thermal self-sufficient condition was studied. The gasification results showed that the syngas production significantly increases with the increase of temperature. The proper gasifying temperature for three processes is at 750 °C. When the maximum syngas molar flow rate was considered, it was found that the use of steam (at S/B of 0.6) and steam-air (at S/B of 0.8 and A/B of 0.04) in gasification can achieve this criterion. Both processes can provide syngas molar flow rate as ∼149 kmol/h. However, it was found that thermal self-sufficient operation is possible when air and steam-air are used as gasifying agent. The result indicated that syngas molar flow rate obtained from air gasification (at A/B of 1.309) is more than that from steam-air gasification (at S/B of 0.1 and A/B of 1.375). In order to obtain the cleaner production of syngas, the absorption process with capturing CO2 and H2S was studied via using monoethanolamine (MEA) as solvent. The optimal column pressure is 40 bars and the number of trays equals to 10. To obtain the H2S content below 0.1 mg/m3, the MEA molar flow rates are 325, 450, and 465 kmol/h for steam, air, and steam-air gasification processes, respectively.

Key factors influencing the environmental performance of pyrolysis, gasification and incineration Waste-to-Energy technologies

Waste-to-Energy (WtE) has started playing an increasingly important role in the recovery of energy from municipal solid waste (MSW). A number of WtE technologies are being developed. However, selecting a more environmentally sustainable option is difficult due to data limitation and methodological inconsistencies. Using life cycle assessment (LCA) as a tool, this paper aims to identify key factors influencing the potential environmental impacts of four representative WtE technologies, namely the incineration (S1), pyrolysis (S2), gasification (S3), and gasification coupled with ash melting (S4). The systems are constructed using inventory data based on on-site operation of several industrial-scale reference plants. A comprehensive sensitivity analysis is conducted, assessing a range of critical input parameters, processes, operating conditions and modelling assumptions. The results demonstrate that all analysed WtE systems exhibit environmental benefits (i.e. negative environmental impacts) for most of the impacts, while S3 seems to be more optimal due to an intermediate syngas cleaning process, which results in both reduced emissions and increased energy recovery. Parameters driving the environmental impacts are energy recovery efficiency, feedstock variability, NOx and CO2 emissions at stack, and recycling of metals. Moreover, the overall ranking of different WtE systems is strongly dependent on operating conditions, such as effectiveness of the air pollution control process, utilization pathway of pyrolysis char, and to a lesser extent, bottom ash management (landfill or recycling). The LCA modelling conditions, such as substituted source of electricity, choice of functional unit and time frame are also shown to significantly affect the quantified environmental performance. Finally, the study highlights the directions, towards which, efforts should be focused throughout all stages of each WtE technology to obtain further improvements.

Experimental analysis and preliminary assessment of an integrated thermochemical process for production of low-molecular weight biofuels from municipal solid waste (MSW)

This work explores the use of advanced thermal technologies for the conversion of refuse derived fuel prepared from MSW into clean syngas suitable for catalytic transformation into light hydrocarbon products. In particular, the possibilities for the specific production of C1–C4 hydrocarbons utilising a good quality syngas produced by two-stage plasma assisted gasification method are investigated. A number of catalytic tests were prepared with modified chemistry to evaluate the preliminary component activities on real waste-derived syngas. C1–C4 paraffins formed in all cases as a main products, with different product distribution for different conditions examined (up to 95% bioSNG on hydrocarbon product for supported nickel, 40% bioLPG for Cu–Zn/ZSM-5 catalysts mix). CO2 was the main byproduct with outlet concentrations ranging from 10 to 50% in volume. When increasing H2:CO in the syngas by external addition of hydrogen, CO conversion increases, as well as paraffin selectivity and hydrocarbons yield. Projections on a 65 MW thermal input bioSNG plant show that if 40 MW of electrical output from renewable sources are used to power a PEM stack during high power availability, the production of bioSNG could be increased by more than 33%, with a simultaneous reduction in CO2 emissions of more than 43%.