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Biomass gasification for energy purposes has several advantages, such as the mitigation of global warming and national energy independency. In the present work, the data from an innovative and intensified steam/oxygen biomass gasification process, integrating a gas filtration step directly inside the reactor, are presented. The produced gas at the outlet of the 1 MWth gasification pilot plant was analysed in terms of its main gaseous products (hydrogen, carbon monoxide, carbon dioxide, and methane) and contaminants. Experimental test sets were carried out at 0.25–0.28 Equivalence Ratio (ER), 0.4–0.5 Steam/Biomass (S/B), and 780–850 °C gasification temperature. Almond shells were selected as biomass feedstock and supplied to the reactor at approximately 120 and 150 kgdry/h. Based on the collected data, the in-vessel filtration system showed a dust removal efficiency higher than 99%-wt. A gas yield of 1.2 Nm3dry/kgdaf and a producer gas with a dry composition of 27–33%v H2, 23–29%v CO, 31–36%v CO2, 9–11%v CH4, and light hydrocarbons lower than 1%v were also observed. Correspondingly, a Low Heating Value (LHV) of 10.3–10.9 MJ/Nm3dry and a cold gas efficiency (CGE) up to 75% were estimated. Overall, the collected data allowed for the assessment of the preliminary performances of the intensified gasification process and provided the data to validate a simulative model developed through Aspen Plus software.

Production of energy or chemicals from biomass and several waste substrates appears a concrete strategy for replacing fossil fuels and reducing carbon dioxide emissions in the atmosphere. In particular, methanol from biomass or bio-waste is considered a reliable energy vector and key intermediate for industrial chemistry. Currently, methanol is industrially produced via syngas conversion using natural gas as the main feedstock. Bio-methane produced via anaerobic digestion (AD) of Organic Fraction Municipal Solid Wastes (OFMSW) may be used as an alternative to natural gas for production of syngas with optimal composition via commercialized reforming processes. In this work, a techno-environmental assessment for methanol production from biogas is presented and discussed. In particular, three case studies were assessed to minimize the environmental impact of bio-methanol production.

Phenol is a major component in the scrubber wastewater used for syngas purification in biomass-based gasification plants. Adsorption is a common strategy for wastewater purification, and carbon materials, such as activated carbons and biochar, may be used for its remediation. In this work, we compare the adsorption behavior towards phenol of two biochar samples, produced by pyrolysis and gasification of lignocellulose biomass, with two commercial activated carbons. Obtained data were also used to assess the effect of textural properties (i.e., surface area) on phenol removal. Continuous tests in lab-scale columns were also carried out and the obtained data were processed with literature models in order to obtain design parameters for scale-up. Results clearly indicate the superiority of activated carbons due to the higher pore volume, although biomass-derived char may be more suitable from an economic and environmental point of view. The phenol adsorption capacity increases from about 65 m/g for gasification biochar to about 270 mg/g for the commercial activated carbon. Correspondingly, service time of commercial activated carbons was found to be about six times higher than that of gasification biochar. Finally, results indicate that phenol may be used as a model for characterizing the adsorption capacity of the investigated carbon materials, but in the case of real waste water the carbon usage rate should be considered at least 1.5 times higher than that calculated for phenol.

This paper addresses the study of a pyro-gasification plant designed, built, and operated to recover inert metals from different types of solid waste. Experimental tests were carried out using pulper as the solid waste. However, while a reliable composition analysis of the produced syngas was carried out, a precise composition evaluation of the pulper used during the experimental activities was not performed and the related data were characterized by unacceptable uncertainty. Therefore, with the aim of reliably characterizing the plant operation, a thermochemical model of the gasification process was setup to simulate the equilibrium operation of the plant and a vector optimization methodology was used to calibrate the numerical model. Then, a decision-making problem was solved to identify the most suitable optimal solution between those belonging to the Pareto optimal front, thus obtaining reliable composition data for the adopted pulper waste. In particular, four different identification criteria were applied for the selection of small subset of solutions over the 3138 dominant solutions found. Among them, the solution (i.e., set of calibration parameters) that minimizes the experimental-numerical difference between the lower heating value of the produced syngas seemed to provide the most reliable approximation of the real plant operation. Finally, a possible plant configuration is proposed for the energetic valorization of the pulper waste and its overall conversion process efficiency is estimated.

This paper explores a possible waste-based economy transition strategy. Digestate from the organic fraction of municipal solid waste (OFMSW) is considered, as well as a low-added value product to be properly valorized. In this regard, air gasification may be used to produce syngas. In this work, the production of methanol, hydrogen, or electricity from digestate-derived syngas was assessed by ChemCAD process simulation software. The process scheme of methanol production comprises the following parts: water gas shift (WGS) with carbon capture and storage units (CCS), methanol synthesis, and methanol purification. In the case of hydrogen production, after WGS-CCS, hydrogen was purified from residual nitrogen by pressure swing absorption (PSA). Finally, for electricity production, the digestate-derived syngas was used as fuel in an internal combustion engine. The main objective of this work is to compare the proposed scenarios in terms of CO2 emission intensity and the effect of CO2 storage. In particular, CCS units were used for methanol or hydrogen production with the aim of obtaining high equilibrium yield toward these products. On the basis of 100 kt/year of digestate, results show that the global CO2 savings were 80, 71, and 69 ktCO2eq/year for electricity, methanol, and hydrogen production, respectively. If carbon storage was considered, savings of about 105 and 99 ktCO2eq/year were achieved with methanol and hydrogen production, respectively. The proposed scenarios may provide an attractive option for transitioning into methanol or hydrogen economy of the future.

In this study, a new configuration where syngas produced by downdraft gasifier is feed directly in an externally fired air turbine is discussed. Attention was posed towards the critical component of this configuration: the heat exchanger. To achieve acceptable electrical efficiencies, high temperature of the air at the inlet turbine section was imposed. A code for heat exchanger design was built by using Matlab, while the geometrical optimization was performed by using modeFRONTIER by imposing a multi-objective function to maximize the overall heat transfer coefficient and minimize both costs and pressure drops across the equipment. İ 2018 The Authors. Published by Elsevier Ltd.

Submicronic powder of silicon carbide was synthesized in a pilot novel radiofrequency plasma torch reactor. The precursors were pyrolysis char and silica powders both with micrometric size. The mass rate of the precursor powder varied in the range 600-2500 g/h. The maximum test time was approximately 3 h. With the goal to increase the process yield, several technical measures were implemented. Silicon carbide yield was above 70 wt% when the plasma flame was confined by a tube that prolonged the residence time of the reactants at the useful temperature for the advancement of reaction. The silicon carbide was characterized by XRD, SEM, and DLS. Both α and β-crystalline phases were detected. Resumo Pó submicrométrico de carboneto de silício foi sintetizado em um novo reator piloto de tocha a plasma por radiofrequência. Os precursores foram pós de cinza de pirólise e sílica com tamanhos micrométricos. A taxa de massa do pó de precursor variou na faixa de 600-2500 g/h. O tempo máximo do teste foi de aproximadamente 3 h. Com o objetivo de aumentar o rendimento do processo, várias medidas técnicas foram implementadas. O rendimento de carbeto de silício foi superior a 70% quando a chama de plasma foi confinada por um tubo que prolongou o tempo de residência dos reagentes à temperatura útil para o avanço da reação. O carbeto de silício foi caracterizado por DRX, MEV e DLS. Ambas as fases cristalinas α e β foram detectadas.

The goal of this work is to investigate the potentiality of energetic recovery by sewage sludge gasification. Experimental gasification tests were carried out in a bench scale rotary kiln under simulated autothermal condition. The mass rate of sludge was in the range 170–260 g/h. The gasification temperature was varied from 750 to 850 °C, equivalence ratio was increased up to 0.24. The tests run for about 3 h. Input and output streams of the process were quantified and analyzed as to assess the cold gas efficiency. Tar content in the raw gas was determined as well. The main drawbacks occurred during the tests were highlighted to have a realistic frame of the experimented technology. © 2017 Elsevier Ltd

In this paper a small Organic Rankine Cycle (ORC) plant was tested under different operating conditions and by using refrigerants (R245fa) as working fluids. In particular, attention was posed towards the scroll expander of the power plant in order to identify experimental parameters to use in its predictive semi-empirical model. Experimental results obtained by imposing different operating conditions at the expander inlet section (i.e. temperature, pressure, mass flow rate) and different temperature at the condensation section, were used to validate the mathematical model. An in-house code (MatLab/Scilab based) using CoolProp library for the accurate evaluation of fluid properties, was optimized by using a genetic algorithm implemented in modeFrontier software. Thus, the validated model was used in predictive mode to evaluate the machine performances. İ 2018 The Authors. Published by Elsevier Ltd.

Automotive shredder residue (ASR) can create difficulties when managing, with its production increasing. It is made of different type of plastics, foams, elastomers, wood, glasses and textiles. For this reason, it is complicated to dispose of in a cost effective way, while also respecting the stringent environmental restrictions. Among thermal treatments, pyrolysis seems to offer an environmentally attractive method for the treatment of ASR; it also allows for the recovery of valuable secondary materials/fuels such as pyrolysis oils, chars, and gas. While, there is a great deal of significant research on ASR pyrolysis, the literature on higher scale pyrolysis experiments is limited. To improve current literature, the aim of the study was to investigate the pyrolysis of ASR in a bench scale rotary kiln. The Italian ASR was separated by dry-sieving into two particle size fractions: d 30mm. Both the streams were grounded, pelletized and then pyrolyzed in a continuous bench scale rotary kiln at 450, 550 and 650°C. The mass flow rate of the ASR pellets was 200-350g/h and each test ran for about 4-5h. The produced char, pyrolysis oil and syngas were quantified to determine product distribution. They were thoroughly analyzed with regard to their chemical and physical properties. The results show how higher temperatures increase the pyrolysis gas yield (44wt% at 650°C) as well as its heating value. The low heating value (LHV) of syngas ranges between 18 and 26MJ/Nm3dry. The highest pyrolysis oil yield (33wt.%) was observed at 550°C and its LHV ranges between 12.5 and 14.5MJ/kg. Furthermore, only two out of the six produced chars respect the LHV limit set by the Italian environmental regulations for landfilling. The obtained results in terms of product distribution and their chemical-physical analyses provide useful information for plant scale-up.

The thermodynamic Model "Gibbs Free Energy Gradient Method" (GMM), published on the Vol. 90 (2011) of this Journal and validated with literature data, is now applied to the simulation of an experimental campaign realized at the ENEA Research Centre of Trisaia (Italy). The GMM well reproduces the experimental results of steam gasification of refuse-derived fuel (RDF) obtained on two laboratory and pilot scale rotary kilns. Consequently, the experimental syngas composition is put in relation to the main process parameters through a new approach incorporating the GMM for identifying a reliable correlation between the extent of reactions and the gasifier temperature. This correlation appears independent from the scale of the rotary kiln and the residence time in the investigated range of variables. On this basis, the GMM is adapted to become a tool for designing industrial gasifiers starting from experimental data since the required final composition of the syngas and the required performances may be obtained by designing a gasification zone operating at the temperature calculated by the proposed method. It is believed that this procedure is extendable to other geometries and different type of apparatus by studying and including the effect of other parameters. © 2016 Elsevier Ltd. All rights reserved.

Since last decade of twentieth century, the change in cane harvesting method from manual harvesting of burned cane to mechanical harvesting of green cane brought the real possibility of sugarcane-trash energy use. The sugarcane-trash, also called Sugarcane Agricultural Residues (SCAR) represents 1/3 of total sugarcane energy content. Despite SCAR is considered today the main unexplored energy reserve in the sugarcane agro-industry a negligible part of this residues is used. Starting from the analysis of the current situation and environmental aspects described in Part1 of the present work (Alonso Pippo et al. in Waste Biomass Valoriz 1), an assessment on socio-economic aspects of SCAR and energy use was carried out. The impact of sugarcane mechanized harvesting on employment was described. The food versus biofuels production from crops was analyzed. SCAR characteristic in face 2nd generation biofuels requirements was treated. The social aspects related to land use were evaluated. A Linear Programming model for profitability maximization was used in order to estimate economical benefits derived from SCAR energy use. The model solution showed that among the variables should be considered in order to maximize profitability special attention deserves: sugarcane production and SCAR transportation cost. It seems to be that sugarcane mechanized harvesting combined with train transport are among the best infrastructure conditions to maximize the profit. When it is delivered to sugar-mill by train SCAR cost can be up to five times cheaper than when it is delivered using articulated lorries. Assuming SCAR energy use for electricity cogeneration as main priority, it was calculated the optimal size for sugarcane factory from techno-economic point of view. An added value/added cost analysis on SCAR energy use at a medium size factory was carried out.

The importance of Sugarcane-Trash energy use, also called Sugarcane Agricultural Residues (SCAR) or Barbojo was analyzed in the light of 2nd generation Biofuels. The current challenges and opportunities of SCAR energy use were treated. An analysis focused on current Brazilian situation and experiences around the world, was carried out. The most probable routes for 2nd generation Bioethanol production suitability: Biomass to Liquid and Bio-enzymatic were compared in Brazil. The Brazilian Sugarcane Agro-Industry particularities and its influence on SCAR energy use were analyzed. The most probable use of SCAR, in a short and mid term, is as boiler feedstock. The key environmental aspects related to SCAR use were analyzed. The SCAR decomposition process and its influence into the CO2 emission reduction were explained. The weed control effect of SCAR left in the field was examined.

There are more than 70 sugar producer countries around the world. Most of them are underdeveloped and poor. Especially for the underdeveloped, 3 rd world, the sugarcane residues disposal has first order priority. The lack of an alternative energy carrier to electricity with storage capability for use in off-season has to date been an unsolvable question for the sugar agro-industry. The improvement of cogeneration capacity via implementation of more efficient cogeneration systems and the barriers for their implementation were analyzed. A techno-economic assessment was carried out regarding the three most probable scenarios of sugar producer countries today. The biomass availability and high investment costs continue to be the main barriers to overcome in order to produce Bio-oil starting from sugarcane biomass solid residues.

The main objective of the present experimental investigation was to evaluate the effects of using different bacteria inoculums at identical technical settings on the anaerobic digestion process for the treatment of semi-solid organic waste available from the orthofruit market. As a possible means to improve the biogas production, as well as reduce their pollution potential, the idea of using recycled digested sludge from the reactor, along with the orthofruit waste, while operating the reactor at maximum retention period has been applied. Purification of the biogas produced was done by means of CO2 adsorption, resulting in a higher CH4/CO2 ratio and, thus, improving its use as fuel for power generation.

The main objective of the present research work is to evaluate both the process performance and characteristics of the products obtained from the treatment of automobile shredder residue (ASR) using a pilot scale experimental pyrolysis plant operating under different load and varying process temperatures. ASR samples used for the treatment, solid and liquid by-products obtained and syngas produced were analysed both through on-line monitoring (gas) and laboratory analysis. Brief descriptions of the plant as well as the preliminary experimental results obtained are presented here.

The goal of the present work was to carry out a review of the disposal practices for the agro-industry’s sugarcane residue and the trends of energy use in Cuba. The lack of an alternative energy carrier to electricity with storage capability for use in off-season has to date been an unsolvable question. The improvement of cogeneration capacity via implementation of CEST or BIG/GTCC and the barriers for their implementation, the introduction of a medium size (3 ton/h) fast pyrolysis module (FPM3) as a solution for off-season energy demand in the agro-industry, and an assessment of the energy required to do so, were also analyzed. Bio-oil production from bagasse and sugarcane agriculture residues (SCAR) and their particularities at the sugar mill are treated. The influence of sugar facility production process configuration is analyzed. The fast pyrolysis products and the trends of their end uses in Cuba are presented. The production cost of a ton of Bio-oil for FPM3 conditions was calculated at 155 USD/ton and the payback time as a function of selling price between 160 and 110 USD/ton was estimated to be from 1.5 to 4 years. The economic feasibility of the FPM3 was estimated, comparing the added values for three scenarios: 1st case, currently-used sugar production, 16.5 USD/ton of cane; 2nd case, factoring in the cogeneration improvement, 27 USD/ton of cane; and 3rd case, with cogeneration improvement and Bio-oil production, 40 USD/ton of cane. The energy use of SCAR and the introduction of FPM3 in the sugar mill are promising improvements that could result in a potential surplus of 80 kW he/ton of cane in-season, or 6 × 106 ton of Bio-oil (LHV=15 MJ/kg) for use off-season in a milling season of 4 million tons of raw sugar.

The aim of this work is the evaluation, on a pilot scale, of scrap tyre pyrolysis process performance and the characteristics of the products under different process parameters, such as temperature, residence time, pressure, etc. In this frame, a series of tests were carried out at varying process temperatures between 550 and 680 °C, other parameters being equal. Pyrolysis plant process data are collected by an acquisition system; scrap tyre samples used for the treatment, solid and liquid by-products and produced syngas were analysed through both on-line monitoring (for gas) and laboratory analyses. Results show that process temperature, in the explored range, does not seem to seriously influence the volatilisation reaction yield, at least from a quantitative point of view, while it observably influences the distribution of the volatile fraction (liquid and gas) and by-products characteristics.

The lack of an alternative energy carrier to electricity with storage capability for use in off-season has to date been an unsolvable question for the sugar agroindustry. The improvement in cogeneration capacity via implementation of condensing extraction steam turbines or biomass integrated gasifier/gas turbine combined cycle and the barriers for their implementation were analyzed. The introduction of a fast pyrolysis (3 tons/h) module (FPM3) as a solution for off-season energy demand in the sugarcane agroindustry was also analyzed. The production cost of 1 ton of bio-oil for FPM3 condition was calculated at 87 USD/ton of bio-oil (0.104 USD/l of bio-oil). The economic feasibility of the FPM3 was estimated, comparing the added values for two alternatives: first alternative regarding the sugar and bioethanol simultaneous production (first generation biofuel production) and second alternative regarding the sugar and bio-oil simultaneous production (second generation biofuel production). Although the highest added value figure for a ton of sugarcane (49.30 USD) was gotten by the second alternative, the bioethanol production for cars fuel continues to be most attractive business option because of large fuel ethanol market demand.

The aim of this study is the characterization of recycled carbon fibres, in view of their potential application in long-fibre reinforced thermoplastic composite. The fibres were obtained from epoxy matrix composite panels, applying a patented process that includes the pyrolisis of the matrix followed by an upgrading of the fibres. Then, recycled fibres were further subjected to thermal and acid treatments in order to modify their surface morphology and chemistry. Scanning electron microscopy and energy dispersive spectrometry were used to characterize the morphological and compositional changes of the fibre surface. The fibres were characterized in terms of mechanical properties and adhesion to an epoxy matrix. The fibres treated by thermal processes at high temperatures (600°C) were shown to be too severely damaged, making them unsuitable for the production of fibre-reinforced composites. A thermal treatment at lower temperatures (450°C) involved a very limited damaging without any evident chemical modification of the fibre surface, which in turn involved a limited increase of the adhesion properties to an epoxy matrix. Chemical treatment by nitric acid caused a very limited damage of fibres, coupled with a significant modification of surface chemistry, which in turn involved a further increase of the fibre/matrix adhesion properties.