The use of hydrogen as an energy vector has been considered as one promising way to attend societ... more The use of hydrogen as an energy vector has been considered as one promising way to attend society decarbonization. Hydrogen can be used as a chemical to store electricity and as a fuel to electric fuel cell mobility. This work makes hydrogen production potential economical evaluation of 5 real solar photovoltaic installations intended primarily for self-consumption. The surplus electrical energy can be used to produce hydrogen, which will be used later as a form of energy, potentially in an application. That provides greater economic value. Hydrogen serves as an important career to the storage of energy and can be more interesting and competitive than a battery-based solution. The results show that the use of hydrogen is only economically viable for mediumsized installations, greater than 300MW and for the production of hydrogen for mobility.
In the current world energy scenario with rising prices and climate emergencies, the renewable en... more In the current world energy scenario with rising prices and climate emergencies, the renewable energy sources are essential for reducing pollution levels triggered by carbon‐based fuels. Hydrogen rises in the world energy scenario as an important non‐carbon‐based energy able to replace fossil fuels. For this reason, the rapid development of hydrogen‐related technology has been seen in recent years. This review paper covers hydrogen energy systems from fossil fuel‐based hydrogen production, biomass and power from renewable energy sources, to hydrogen storage in compressed gases, liquefied and solid materials, and hydrogen‐based power generation technology. It represents a quiet complete set of references that may be effective in increasing the prospects of hydrogen as a fuel in the coming years. The main conclusions drawn are that natural gas and coal supply nearly all of the current hydrogen. The commercially available technologies for hydrogen production are steam methane reforming, partial oxidation, and alkaline electrolysis. The most economical methods for hydrogen production are partial oxidation, steam methane reforming, coal gasification, and biomass gasification. Metallic cylindrical reservoirs are the most promising alternative to underground storage of compressed hydrogen at large scales. Some metal compounds and composites can store a significant amount of hydrogen while maintaining reasonable adsorption and desorption kinetics. The transportation sector is likely to see widespread use of hydrogen in the future, helping to reduce pollution. Vehicles can be powered by fuel cells, which are much more efficient than internal combustion engines. There are still several obstacles in the way of widespread hydrogen utilization. The first one is that the cost of producing hydrogen from low‐carbon sources is elevated. As the cost of renewable energy declines and hydrogen production is scaled up, it is anticipated that the hydrogen production costs would decrease over the next years. Innovative technologies are expected to increase the interest on thermochemical hydrogen production to massively substitute electrochemical technologies since they are theoretically cost‐effective. More research is needed to fix concerns with some of the thermochemical cycles in order to rise its maturity. Increasing the chemical reaction conversion ratios, which can be resolved utilizing nonequilibrium reactions, is one of them. The transportation sector is likely to see extensive use of hydrogen in the future, helping to reduce carbon dioxide emissions. The power required by vehicles may be supplied by fuel cells, which are more efficient than internal combustion engines.
Abstract The growing production of non-recyclable urban wastes generates environmental problems t... more Abstract The growing production of non-recyclable urban wastes generates environmental problems that impose new alternatives for their energetic valorisation. Nonetheless, some of these wastes do not have adequate properties to be directly used in waste-to-energy technologies, thus requiring adequate pre-treatments to improve their fuel properties. This work aimed to evaluate dry and hydrothermal carbonisation (DC and HTC) as technologies to convert solid recovered fuel (SRF) from construction and municipal solid wastes to biochars or hydrochars with improved fuel quality. The operational parameters evaluated were temperature, mass ratio of SRF:water, and incorporation of a liquid additive (used cooking oil, UCO). The chars were characterised for chemical composition, calorific value, TGA profiles and surface functional groups. The chemical oxygen demand (COD), concentration of total phenols, pH, conductivity and the main components in process waters were determined. Results showed an improvement of fuel characteristics in terms of hydrophobicity and calorific value, enabling the use of chars for waste-to-energy technologies. HTC produced hydrochars with better fuel characteristics, presenting calorific values of 28–33 MJ/kg db, and lower average ash and chlorine contents (2.8 wt% db and 3.1 wt% db, respectively). The addition of UCO improved these fuel characteristics. However, the generation of an effluent that needs further decontamination and the lower amount of moisture present in SRF possibly made DC more attractive in terms of energy and costs requirements. A treatment at 350 °C during 30 min was recommended for a good compromise among process costs and char properties.
The energetic valorisation of wastes through gasification is a promising solution with a better e... more The energetic valorisation of wastes through gasification is a promising solution with a better environmental impact in terms of pollutant emissions compared with incineration, landfilling, and heat and power generation from fossil fuels. However, techno-economic studies are imperative to define the viability of these technologies and to optimise heat and power consumptions and costs. This work intended to develop a techno-economic analysis for a small-scale gasification plant processing mixtures of solid recovered fuels and sewage sludge, assuming a capacity of 883 kg/h and two different sale scenarios: (A) production of electric energy, and (B) production of hydrogen. Gasification tests and mass and energy flow analyses were carried out for the economic assessment. The results showed that both scenarios presented viability for implementation. Although scenario A was more attractive in the short-term period due to the lower payback period (9 year) and higher internal rate of return (IRR, 7.5%), the other option was more favourable at the end of plant's life once the net present value was greater (1,801,700 €). Based on the results of a sensitivity analysis, a conclusion could be drawn that the economic indicators payback period and IRR were most influenced by capital expenditures applied in the plant.
Gasification is a promising thermochemical technology used to convert waste materials into energy... more Gasification is a promising thermochemical technology used to convert waste materials into energy with the introduction of low amounts of an oxidant agent, therefore producing an environmental impact that is lower when compared to incineration and landfilling. Moreover, gasification allows a sustainable management of wastes and reduces the use of fossil fuels responsible for the increment of greenhouse gases. This work aimed to perform gasification tests with solid recovered fuels (SRF) containing organic fractions mainly retrieved from construction and demolition wastes to assess the potential for energy conversion. Tests were conducted in a pilot-scale downdraft gasifier (maximum feedstock input of 22 kg/h) at c.a. 800 °C, using SRF samples containing different proportions of polymeric wastes ranging between 0 and 20 wt %. Gas and chars obtained as by-products were analysed to evaluate their properties and to establish valid pathways for their valorisation. The addition of polymer...
The 5th Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology - CIEEMAT 2019, 2019
co-gasification experiments with mixtures in various proportions of waste wood (WW) and sewage sl... more co-gasification experiments with mixtures in various proportions of waste wood (WW) and sewage sludge (SS) were performed in a downdraft gasifier, in order to evaluate process performance and properties of gas and chars. Addition of SS improved the energy conversion efficiency and product gas yield, and minimised the formation of tars. Char production was greater, with formation of agglomerations inside the reactor. The optimal waste mixture contained 87.5 wt.% WW and 12.5 wt.% SS, generating a product gas yield of 2.9 m3/kg waste with a calorific value of 4.8 MJ/m3, and a tar production of 4.7 g/kg waste.
A large number of mould manufactures need to reduce cost production. In fact, the production of a... more A large number of mould manufactures need to reduce cost production. In fact, the production of a part by foundry techniques is influenced by its complex geometry configuration, which affects the solidification conditions and subsequent cooling. The simulation of heat transfer phenomena between metal and mould helps to reduce or even eliminate the need of corrective alterations of the mould. This approach will help to reduce its cost. The main objective of this paper is to describe the development of a finite volume method in order to simulate the heat transfer phenomena during the phase change process. Because of the mould design complexity, the finite volume is described using the generalized curvilinear formulation.Copyright ?? 2003 by ASME
Abstract A two-dimensional CFD computational model has been developed to describe the gasificatio... more Abstract A two-dimensional CFD computational model has been developed to describe the gasification process of coffee husks within a fluidized bed reactor. The Eulerian - Eulerian method is used for both gas and solid phases to provide an explanation for mass exchange, energy, and momentum. The results were obtained after comparing both the numerical model and the experimental data for validation. The current model also predicts the effects of equivalence ratio and moisture content on gasification temperature, and provides sensitive analysis of the model of the produced syngas composition in addition to the higher heating value and cold gas efficiency. The simulated syngas composition was found to be in good agreement with the experiment. The high moisture content of coffee husk has negative effects on cold gas efficiency and HHV, an effect that decreases as the equivalence ratio increases.
The use of hydrogen as an energy vector has been considered as one promising way to attend societ... more The use of hydrogen as an energy vector has been considered as one promising way to attend society decarbonization. Hydrogen can be used as a chemical to store electricity and as a fuel to electric fuel cell mobility. This work makes hydrogen production potential economical evaluation of 5 real solar photovoltaic installations intended primarily for self-consumption. The surplus electrical energy can be used to produce hydrogen, which will be used later as a form of energy, potentially in an application. That provides greater economic value. Hydrogen serves as an important career to the storage of energy and can be more interesting and competitive than a battery-based solution. The results show that the use of hydrogen is only economically viable for mediumsized installations, greater than 300MW and for the production of hydrogen for mobility.
In the current world energy scenario with rising prices and climate emergencies, the renewable en... more In the current world energy scenario with rising prices and climate emergencies, the renewable energy sources are essential for reducing pollution levels triggered by carbon‐based fuels. Hydrogen rises in the world energy scenario as an important non‐carbon‐based energy able to replace fossil fuels. For this reason, the rapid development of hydrogen‐related technology has been seen in recent years. This review paper covers hydrogen energy systems from fossil fuel‐based hydrogen production, biomass and power from renewable energy sources, to hydrogen storage in compressed gases, liquefied and solid materials, and hydrogen‐based power generation technology. It represents a quiet complete set of references that may be effective in increasing the prospects of hydrogen as a fuel in the coming years. The main conclusions drawn are that natural gas and coal supply nearly all of the current hydrogen. The commercially available technologies for hydrogen production are steam methane reforming, partial oxidation, and alkaline electrolysis. The most economical methods for hydrogen production are partial oxidation, steam methane reforming, coal gasification, and biomass gasification. Metallic cylindrical reservoirs are the most promising alternative to underground storage of compressed hydrogen at large scales. Some metal compounds and composites can store a significant amount of hydrogen while maintaining reasonable adsorption and desorption kinetics. The transportation sector is likely to see widespread use of hydrogen in the future, helping to reduce pollution. Vehicles can be powered by fuel cells, which are much more efficient than internal combustion engines. There are still several obstacles in the way of widespread hydrogen utilization. The first one is that the cost of producing hydrogen from low‐carbon sources is elevated. As the cost of renewable energy declines and hydrogen production is scaled up, it is anticipated that the hydrogen production costs would decrease over the next years. Innovative technologies are expected to increase the interest on thermochemical hydrogen production to massively substitute electrochemical technologies since they are theoretically cost‐effective. More research is needed to fix concerns with some of the thermochemical cycles in order to rise its maturity. Increasing the chemical reaction conversion ratios, which can be resolved utilizing nonequilibrium reactions, is one of them. The transportation sector is likely to see extensive use of hydrogen in the future, helping to reduce carbon dioxide emissions. The power required by vehicles may be supplied by fuel cells, which are more efficient than internal combustion engines.
Abstract The growing production of non-recyclable urban wastes generates environmental problems t... more Abstract The growing production of non-recyclable urban wastes generates environmental problems that impose new alternatives for their energetic valorisation. Nonetheless, some of these wastes do not have adequate properties to be directly used in waste-to-energy technologies, thus requiring adequate pre-treatments to improve their fuel properties. This work aimed to evaluate dry and hydrothermal carbonisation (DC and HTC) as technologies to convert solid recovered fuel (SRF) from construction and municipal solid wastes to biochars or hydrochars with improved fuel quality. The operational parameters evaluated were temperature, mass ratio of SRF:water, and incorporation of a liquid additive (used cooking oil, UCO). The chars were characterised for chemical composition, calorific value, TGA profiles and surface functional groups. The chemical oxygen demand (COD), concentration of total phenols, pH, conductivity and the main components in process waters were determined. Results showed an improvement of fuel characteristics in terms of hydrophobicity and calorific value, enabling the use of chars for waste-to-energy technologies. HTC produced hydrochars with better fuel characteristics, presenting calorific values of 28–33 MJ/kg db, and lower average ash and chlorine contents (2.8 wt% db and 3.1 wt% db, respectively). The addition of UCO improved these fuel characteristics. However, the generation of an effluent that needs further decontamination and the lower amount of moisture present in SRF possibly made DC more attractive in terms of energy and costs requirements. A treatment at 350 °C during 30 min was recommended for a good compromise among process costs and char properties.
The energetic valorisation of wastes through gasification is a promising solution with a better e... more The energetic valorisation of wastes through gasification is a promising solution with a better environmental impact in terms of pollutant emissions compared with incineration, landfilling, and heat and power generation from fossil fuels. However, techno-economic studies are imperative to define the viability of these technologies and to optimise heat and power consumptions and costs. This work intended to develop a techno-economic analysis for a small-scale gasification plant processing mixtures of solid recovered fuels and sewage sludge, assuming a capacity of 883 kg/h and two different sale scenarios: (A) production of electric energy, and (B) production of hydrogen. Gasification tests and mass and energy flow analyses were carried out for the economic assessment. The results showed that both scenarios presented viability for implementation. Although scenario A was more attractive in the short-term period due to the lower payback period (9 year) and higher internal rate of return (IRR, 7.5%), the other option was more favourable at the end of plant's life once the net present value was greater (1,801,700 €). Based on the results of a sensitivity analysis, a conclusion could be drawn that the economic indicators payback period and IRR were most influenced by capital expenditures applied in the plant.
Gasification is a promising thermochemical technology used to convert waste materials into energy... more Gasification is a promising thermochemical technology used to convert waste materials into energy with the introduction of low amounts of an oxidant agent, therefore producing an environmental impact that is lower when compared to incineration and landfilling. Moreover, gasification allows a sustainable management of wastes and reduces the use of fossil fuels responsible for the increment of greenhouse gases. This work aimed to perform gasification tests with solid recovered fuels (SRF) containing organic fractions mainly retrieved from construction and demolition wastes to assess the potential for energy conversion. Tests were conducted in a pilot-scale downdraft gasifier (maximum feedstock input of 22 kg/h) at c.a. 800 °C, using SRF samples containing different proportions of polymeric wastes ranging between 0 and 20 wt %. Gas and chars obtained as by-products were analysed to evaluate their properties and to establish valid pathways for their valorisation. The addition of polymer...
The 5th Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology - CIEEMAT 2019, 2019
co-gasification experiments with mixtures in various proportions of waste wood (WW) and sewage sl... more co-gasification experiments with mixtures in various proportions of waste wood (WW) and sewage sludge (SS) were performed in a downdraft gasifier, in order to evaluate process performance and properties of gas and chars. Addition of SS improved the energy conversion efficiency and product gas yield, and minimised the formation of tars. Char production was greater, with formation of agglomerations inside the reactor. The optimal waste mixture contained 87.5 wt.% WW and 12.5 wt.% SS, generating a product gas yield of 2.9 m3/kg waste with a calorific value of 4.8 MJ/m3, and a tar production of 4.7 g/kg waste.
A large number of mould manufactures need to reduce cost production. In fact, the production of a... more A large number of mould manufactures need to reduce cost production. In fact, the production of a part by foundry techniques is influenced by its complex geometry configuration, which affects the solidification conditions and subsequent cooling. The simulation of heat transfer phenomena between metal and mould helps to reduce or even eliminate the need of corrective alterations of the mould. This approach will help to reduce its cost. The main objective of this paper is to describe the development of a finite volume method in order to simulate the heat transfer phenomena during the phase change process. Because of the mould design complexity, the finite volume is described using the generalized curvilinear formulation.Copyright ?? 2003 by ASME
Abstract A two-dimensional CFD computational model has been developed to describe the gasificatio... more Abstract A two-dimensional CFD computational model has been developed to describe the gasification process of coffee husks within a fluidized bed reactor. The Eulerian - Eulerian method is used for both gas and solid phases to provide an explanation for mass exchange, energy, and momentum. The results were obtained after comparing both the numerical model and the experimental data for validation. The current model also predicts the effects of equivalence ratio and moisture content on gasification temperature, and provides sensitive analysis of the model of the produced syngas composition in addition to the higher heating value and cold gas efficiency. The simulated syngas composition was found to be in good agreement with the experiment. The high moisture content of coffee husk has negative effects on cold gas efficiency and HHV, an effect that decreases as the equivalence ratio increases.
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