464 research outputs found
Sustainability assessment of biomethanol production via hydrothermal gasification supported by artificial neural network
Global warming and climate change urge the deployment of close carbon-neutral technologies via the synthesis of low-carbon emission fuels and materials. An efficient intermediate product of such technologies is the biomethanol produced from biomass. Microalgae based technologies offer scalable solutions for the biofixation of CO2, where the produced biomass can be transformed into value-added fuel gas mixtures by applying thermochemical processes. In this study, the environmental and economic performances of biomethanol production are examined using artificial neural networks (ANNs) for the modelling of catalytic and noncatalytic hydrothermal gasification (HTG). Levenberg-Marquardt and Bayesian Regularisation algorithms are applied to describe the thermocatalytic transformation involving various types of feedstocks (biomass and wastes) in the training process. The relationship between the elemental composition of the feedstock, HTG reaction conditions (380 ?C & ndash;717 ?C, 22.5 MPa & ndash;34.4 MPa, 1 & ndash;30 wt% biomass-to-water ratio, 0.3 min & ndash;60.0 min residence time, up to 5.5 wt% NaOH catalyst load) and fuel gas yield & composition are determined for Chlorella vulgaris strain. The ideal ANN topology is characterised by high training performance (MSE = 5.680E-01) and accuracies (R-2 >= 0.965) using 2 hidden layers with 17-17 neurons. The process flowsheeting of biomass-to-methanol valorisation is performed using ASPEN Plus software involving the ANN-based HTG fuel gas profiles. Cradle-to-gate life cycle assessment (LCA) is carried out to evaluate the climate change potential of biomethanol production alternatives. It is obtained that high greenhouse gas (GHG) emission reduction (-725 kg CO2,eq (t CH3OH)-1) can be achieved by enriching the HTG syngas composition with H2 using variable renewable electricity sources. The utilisation of hydrothermal gasification for the synthesis of biomethanol is found to be a favourable process alternative due to the (i) variable synthesis gas composition, (ii) heat integration, and (iii) GHG emission mitigation possibilities
Measuring circularity in food supply chain using life cycle assessment : refining oil from olive kernel
Valorization of food waste is a potential strategy toward a circular food supply chain. In this regard, measuring the circularity of food waste valorization systems is highly important to better understand multiple environmental impacts. Therefore, this study investigated the circularity of a food waste valorization system (refining oil from olive kernel) using a life cycle assessment methodology. An inventory of an industrial-based olive kernel oil production system is also provided in this study. The system boundary was the cradle to the factory gate of the production system. The results indicated that natural gas consumption was the highest contributor to most of the investigated impact categories. The global warming potential of one kg of oil produced from olive kernel was calculated to be 1.37 kg CO(2)eq. Moreover, the calculated damages of 1 kg oil production from olive kernel to human health, ecosystem quality, and resource depletion were 5.29 x 10(-7) DALY, 0.12 PDF center dot m(2)center dot yr., and 24.40 MJ, respectively
Advanced Technology of Waste Treatment
The protection of human health and the environment (representing the main reason for waste management), as well as the sustainable use of natural resources, requires chemical, biological, physical and thermal treatment of wastes. This refers to the conditioning (e.g., drying, washing, comminution, rotting, stabilization, neutralization, agglomeration, homogenization), conversion (e.g., incineration, pyrolysis, gasification, dissolution, evaporation), and separation (classification, direct and indirect (i.e., sensor-based) sorting) of all types of wastes to follow the principles of the waste hierarchy (i.e., prevention (not addressed by this issue), preparation for re-use, recycling, other recovery, and disposal). Longstanding challenges include the increase of yield and purity of recyclable fractions and the sustainable removal or destruction of contaminants from the circular economy.This Special Issue on “Advanced Technology of Waste Treatment” of Processes collects high-quality research studies addressing challenges on the broad area of chemical, biological, physical and thermal treatment of wastes
Key ingredients and recycling strategy of personal protective equipment (PPE): Towards sustainable solution for the COVID-19 like pandemics.
The COVID-19 pandemic has intensified the complications of plastic trash management and disposal. The current situation of living in fear of transmission of the COVID-19 virus has further transformed our behavioural models, such as regularly using personal protective equipment (PPE) kits and single-use applications for day to day needs etc. It has been estimated that with the passage of the coronavirus epidemic every month, there is expected use of 200 billion pieces of single-use facemasks and gloves. PPE are well established now as life-saving items for medicinal specialists to stay safe through the COVID-19 pandemic. Different processes such as glycolysis, hydrogenation, aminolysis, hydrolysis, pyrolysis, and gasification are now working on finding advanced technologies to transfer waste PPE into value-added products. Here, in this article, we have discussed the recycling strategies of PPE, important components (such as medical gloves, gowns, masks & respirators and other face and eye protection) and the raw materials used in PPE kits. Further, the value addition methods to recycling the PPE kits, chemical & apparatus used in recycling and recycling components into value-added products. Finally, the biorenewable materials in PPE for textiles components have been discussed along with concluded remarks
Gasificação direta de biomassa para produção de gás combustível
The excessive consumption of fossil fuels to satisfy the world necessities of
energy and commodities led to the emission of large amounts of greenhouse
gases in the last decades, contributing significantly to the greatest
environmental threat of the 21st century: Climate Change. The answer to this
man-made disaster is not simple and can only be made if distinct stakeholders
and governments are brought to cooperate and work together. This is
mandatory if we want to change our economy to one more sustainable and
based in renewable materials, and whose energy is provided by the eternal
nature energies (e.g., wind, solar). In this regard, biomass can have a main role
as an adjustable and renewable feedstock that allows the replacement of fossil
fuels in various applications, and the conversion by gasification allows the
necessary flexibility for that purpose. In fact, fossil fuels are just biomass that
underwent extreme pressures and heat for millions of years. Furthermore,
biomass is a resource that, if not used or managed, increases wildfire risks.
Consequently, we also have the obligation of valorizing and using this
resource.
In this work, it was obtained new scientific knowledge to support the
development of direct (air) gasification of biomass in bubbling fluidized bed
reactors to obtain a fuel gas with suitable properties to replace natural gas in
industrial gas burners. This is the first step for the integration and development
of gasification-based biorefineries, which will produce a diverse number of
value-added products from biomass and compete with current petrochemical
refineries in the future. In this regard, solutions for the improvement of the raw
producer gas quality and process efficiency parameters were defined and
analyzed. First, addition of superheated steam as primary measure allowed the
increase of H2 concentration and H2/CO molar ratio in the producer gas without
compromising the stability of the process. However, the measure mainly
showed potential for the direct (air) gasification of high-density biomass (e.g.,
pellets), due to the necessity of having char accumulation in the reactor bottom
bed for char-steam reforming reactions. Secondly, addition of refused derived
fuel to the biomass feedstock led to enhanced gasification products, revealing
itself as a highly promising strategy in terms of economic viability and
environmental benefits of future gasification-based biorefineries, due to the
high availability and low costs of wastes. Nevertheless, integrated techno economic and life cycle analyses must be performed to fully characterize the
process. Thirdly, application of low-cost catalyst as primary measure revealed
potential by allowing the improvement of the producer gas quality (e.g., H2 and
CO concentration, lower heating value) and process efficiency parameters with
distinct solid materials; particularly, the application of concrete, synthetic
fayalite and wood pellets chars, showed promising results. Finally, the
economic viability of the integration of direct (air) biomass gasification
processes in the pulp and paper industry was also shown, despite still lacking
interest to potential investors. In this context, the role of government policies
and appropriate economic instruments are of major relevance to increase the
implementation of these projects.O consumo excessivo de combustíveis fósseis para garantir as necessidades e
interesses da sociedade conduziu à emissão de elevadas quantidades de
gases com efeito de estufa nas últimas décadas, contribuindo
significativamente para a maior ameaça ambiental do século XXI: Alterações
Climáticas. A solução para este desastre de origem humana é de caráter
complexo e só pode ser atingida através da cooperação de todos os governos
e partes interessadas. Para isto, é obrigatória a criação de uma bioeconomia
como base de um futuro mais sustentável, cujas necessidades energéticas e
materiais sejam garantidas pelas eternas energias da natureza (e.g., vento,
sol). Neste sentido, a biomassa pode ter um papel principal como uma matéria prima ajustável e renovável que permite a substituição de combustíveis fósseis
num variado número de aplicações, e a sua conversão através da gasificação
pode ser a chave para este propósito. Afinal, na prática, os combustíveis
fósseis são apenas biomassa sujeita a elevada temperatura e pressão durante
milhões de anos. Além do mais, a gestão eficaz da biomassa é fundamental
para a redução dos riscos de incêndio florestal e, como tal, temos o dever de
utilizar e valorizar este recurso.
Neste trabalho, foi obtido novo conhecimento científico para suporte do
desenvolvimento das tecnologias de gasificação direta (ar) de biomassa em
leitos fluidizados borbulhantes para produção de gás combustível, com o
objetivo da substituição de gás natural em queimadores industriais. Este é o
primeiro passo para o desenvolvimento de biorrefinarias de gasificação, uma
potencial futura indústria que irá providenciar um variado número de produtos
de valor acrescentado através da biomassa e competir com a atual indústria
petroquímica. Neste sentido, foram analisadas várias medidas para a melhoria
da qualidade do gás produto bruto e dos parâmetros de eficiência do processo.
Em primeiro, a adição de vapor sobreaquecido como medida primária permitiu
o aumento da concentração de H2 e da razão molar H2/CO no gás produto sem
comprometer a estabilidade do processo. No entanto, esta medida somente
revelou potencial para a gasificação direta (ar) de biomassa de alta densidade
(e.g., pellets) devido à necessidade da acumulação de carbonizados no leito
do reator para a ocorrência de reações de reforma com vapor. Em segundo, a
mistura de combustíveis derivados de resíduos e biomassa residual florestal
permitiu a melhoria dos produtos de gasificação, constituindo desta forma uma
estratégia bastante promissora a nível económico e ambiental, devido à
elevada abundância e baixo custo dos resíduos urbanos. Contudo, devem ser
efetuadas análises técnico-económicas e de ciclo de vida para a completa
caraterização do processo. Em terceiro, a aplicação de catalisadores de baixo
custo como medida primária demonstrou elevado potencial para a melhoria do
gás produto (e.g., concentração de H2 e CO, poder calorífico inferior) e para o
incremento dos parâmetros de eficiência do processo; em particular, a
aplicação de betão, faialite sintética e carbonizados de pellets de madeira,
demonstrou resultados promissores. Finalmente, foi demonstrada a viabilidade
económica da integração do processo de gasificação direta (ar) de biomassa
na indústria da pasta e papel, apesar dos parâmetros determinados não serem
atrativos para potenciais investidores. Neste contexto, a intervenção dos
governos e o desenvolvimento de instrumentos de apoio económico é de
grande relevância para a implementação destes projetos.Este trabalho foi financiado pela The Navigator Company e por Fundos Nacionais através da Fundação para a Ciência e a Tecnologia (FCT).Programa Doutoral em Engenharia da Refinação, Petroquímica e Químic
Advanced Technologies for Biomass
The use of biomass and organic waste material as a primary resource for the production of fuels, chemicals, and electric power is of growing significance in light of the environmental issues associated with the use of fossil fuels. For this reason, it is vital that new and more efficient technologies for the conversion of biomass are investigated and developed. Today, various advanced methods can be used for the conversion of biomass. These methods are broadly classified into thermochemical conversion, biochemical conversion, and electrochemical conversion. This book collects papers that consider various aspects of sustainability in the conversion of biomass into valuable products, covering all the technical stages from biomass production to residue management. In particular, it focuses on experimental and simulation studies aiming to investigate new processes and technologies on the industrial, pilot, and bench scales
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