scholarly journals Potential Water Recovery from Biomass Boilers: Parametric Analysis

Computation ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 53
Author(s):  
Daniele Dondi ◽  
Cristina D. López Robles ◽  
Anna Magrini ◽  
Marco Cartesegna
Keyword(s):  
Fossil Fuels ◽  
Fossil Fuel ◽  
Point Of View ◽  
Energy Output ◽  
Biomass Combustion ◽  
Water Recovery ◽  
Water Production ◽  
Combustion System ◽  
Computational Tool ◽  
Energetic Point

A fundamental component of the losses of convection boilers is localized in the warm fumes that are expelled. In the warm fumes, not only energy is lost, but water is also formed from the combustion reaction in the form of steam which is expelled through the exhaust. Modern fuel boilers recover both the heat from the fumes and the latent heat of condensation from water vapor. Depending on the chemical composition of the fuel, different amounts of steam are produced together with heat and different combustion conditions, such as air in excess. In this article, a computational tool was established to simulate a combustion system mainly (but not only) focusing on the prediction of the amount of water produced. In fact, while steam in fossil fuel boilers is commonly condensed, this is not so when the fuel is a biomass. Furthermore, biomasses could contain moisture in different amounts, thus affecting the production of water and the heat of combustion. The study shows that a ten-fold amount of water is formed from biomass combustion with respect to fossil fuels (when the same energy output is produced). As a result, the recovery of water is amenable in biomasses, both from the energetic point of view and for liquid water production. In fact, the water recovered from the fumes might be also reused in other processes such as the cleaning of fumes or agriculture (after treatment).

scholarly journals Gini and Entropy-Based Spread Indexes for Primary Energy Consumption Efficiency and CO2 Emission

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4938
Author(s):  
Hellinton H. Takada ◽  
Celma O. Ribeiro ◽  
Oswaldo L. V. Costa ◽  
Julio M. Stern
Keyword(s):  
Energy Consumption ◽  
Co2 Emission ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Primary Energy ◽  
Point Of View ◽  
Primary Energy Consumption ◽  
Policy Makers ◽  
Responsible Investment ◽  
Global Spread

Primary energy consumption is one of the key drivers of global CO2 emissions that, in turn, heavily depends on the efficiency of involved technologies. Either improvement in technology efficiency or the expansion of non-fossil fuel consumption requires large investments. The planning and financing of such investments by global policy makers or global energy firms require, in turn, reliable measures of associated global spread and their evolution in time, at least from the point of view of the principles for responsible investment (PRI). In this paper, our main contribution is the introduction of index measures for accessing global spread (that is, measures of inequality or inhomogeneity in the statistical distribution of a related quantity of interest) of technology efficiency and CO2 emission in primary energy consumption. These indexes are based on the Gini index, as used in economical sciences, and generalized entropy measures. Regarding primary energy sources, we consider petroleum, coal, natural gas, and non-fossil fuels. Between our findings, we attest some stable relations in the evolution of global spreads of technology efficiency and CO2 emission and a positive relation between changes in global spread of technology efficiency and use of non-fossil fuel.

scholarly journals Energy efficiency of fossil and renewable fuels

2016 ◽  
pp. 1-7
Author(s):  
Winfried Schäfer
Keyword(s):  
Renewable Energy ◽  
Co2 Emissions ◽  
Energy Supply ◽  
Energy Input ◽  
Fossil Fuels ◽  
Energy Intensity ◽  
Fossil Fuel ◽  
Energy Output ◽  
Engine Fuel ◽  
Wide Range

Assessment results of renewable energy supply in agriculture and forestry are often questionable because 1. the methodology does not describe the nature dependent conditions of agricultural production, 2. there is no standard system boundary, 3. thermodynamic laws are violated and/or ignored, 4. direct and embodied energy is mixed, 5. the mainstream life cycle analysis (LCA) takes downstream and upstream inputs arbitrarily into consideration, depending on the research objectives and the research-funding agency. Thus, the calculation results neglect a wide range of specific energy input figures of upstream and down-stream factors outside farm level resulting in non-comparable figures. The EROI describes the ratio between energy output and input. The advantage of this measure is that energy input and output of fuel supply as well as the resulting CO2 emissions are comparable. There are no standards to calculate the indirect energy input of commodities and services hidden in monetary inputs (insurances, rent for land, subsidies and fees etc.). They are usually excluded because procedures to handle them as energy input are rare. The easiest way to quantify the indirect energy is the use of the energy intensity (EI). Multiplying the price of any good or service with the energy intensity results in a rough estimation of energy embodied in the good or service. Applying the EROI and the EI to compare the efficiency of fossil and renewable energy supply released the following results: Substitution of fossil fuels by renewable ones causes always additional costs. Most known renewable energy supply techniques need more energy than fossil fuel exploitation. Polluting the environment is - for the time being – the most competitive alternative. Renewable engine fuel, produced from biomass, is not competitive with fossil fuels in terms of EROI. The energy of one ha biomass may substitute gasoline to drive a car 40 000 km with biogas. Electric power harnessed from one ha solar panels enables to drive an electric vehicle 5 000 000 km applying the same calculation method. The most efficient way to mitigate CO2 emissions is to include the entropy of agricultural products in energy policy decision making. Albeit wood has a high EROI, processing fuels from wood of low entropy makes no sense: Producing a table from a tree and burning the residues and the table at the end of its lifetime renders the same energy gain as using the tree for fuel only. The EROI of fossil fuels remains probably on high level during the next 50 to 100 years. Oil and gas will be replaced by coal, in Finland also by nuclear power, peat and wood. Although biomass is more renewable than fossil fuels, its EROI is lower and substitution will not reduce CO2 emissions. Climate change may force humankind to reduce fossil fuel consumption. The only sustainable way to achieve this is reduction of fossil fuel exploitation.

Energy After COVID

2020 ◽  
Vol 119 (820) ◽  
pp. 317-322
Author(s):  
Michael T. Klare
Keyword(s):  
Renewable Energy ◽  
Electric Vehicles ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
White Collar ◽  
Peak Oil ◽  
Business Travel ◽  
Reduce Energy Consumption ◽  
The Cost ◽  
Energy Companies

By transforming patterns of travel and work around the world, the COVID-19 pandemic is accelerating the transition to renewable energy and the decline of fossil fuels. Lockdowns brought car commuting and plane travel to a near halt, and the mass experiment in which white-collar employees have been working from home may permanently reduce energy consumption for business travel. Renewable energy and electric vehicles were already gaining market share before the pandemic. Under pressure from investors, major energy companies have started writing off fossil fuel reserves as stranded assets that are no longer worth the cost of extracting. These shifts may indicate that “peak oil demand” has arrived earlier than expected.

Assessing desalination as a sustainable alternative using a multiple criteria decision support model

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
M. B. Fernandes ◽  
M. C. Almeida ◽  
A. G. Henriques
Keyword(s):  
Decision Support ◽  
Energy Production ◽  
Fossil Fuels ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
High Energy ◽  
Economic Benefits ◽  
Multiple Criteria ◽  
Water Production ◽  
Decision Support Model

Desalination technologies provide an alternative for potable water production, having significant potential for application where fresh water scarcity exists. Potential benefits have to be balanced with other factors, such as high costs, high energy consumption, and significant environmental impacts, for the understanding of real risks and gains of desalination within the context of integrated water resources management. Multiple factors can be considered when analysing the viability of a desalination project but often a limited approach is used. The complexity in the analysis lies in finding the alternatives that obey to multiple objectives (e.g. reduced environmental impact, social acceptance, less cost associated). In this paper, development of a methodology based on multiple criteria decision support system for the evaluation and ranking the potential of desalination technologies is described and applied to a Portuguese case study. Relevant factors to the selection of desalination technologies were identified using SWOT analysis and the MACBETH (Measuring Attractiveness by a Categorical Based Evaluation Technique) approach was applied. Technical alternatives considered include reverse osmosis and multi-effect desalination (MED), together with energy production by fossil fuels or solar energy. Production of water by conventional approaches was also considered. Results, for non-economic benefits, show higher score for MED solar but, in the cost-benefit analysis, conventional methods of water production have higher ranking since costs of renewable energies are not yet competitive. However, even if not preferred in economic terms, desalination is ranked significantly above the conventional approaches for non-economic criteria.

scholarly journals New Deterministic Mathematical Model for Estimating the Useful Energy Output of a Medium-Sized Solar Domestic Hot Water System

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2753
Author(s):  
Miroslaw Zukowski ◽  
Walery Jezierski
Keyword(s):  
Thermal Power ◽  
Optimization Procedure ◽  
Climatic Conditions ◽  
Point Of View ◽  
Hot Water ◽  
Energy Output ◽  
Daily Consumption ◽  
Software Environment ◽  
Optical Efficiency ◽  
Domestic Hot Water

According to the authors of this paper, the mathematical point of view allows us to see what sometimes cannot be seen from the designer’s point of view. The aim of this study was to estimate the influence of the most important parameters (volume of heat storage tanks, daily consumption of domestic hot water, optical efficiency, heat loss coefficient, and total area of a solar collector) on the thermal power output of solar domestic hot water (SDHW) system in European climatic conditions. Three deterministic mathematical models of these relationships for Madrid, Budapest, and Helsinki were created. The database for the development of these models was carried out using computer simulations made in the TRNSYS software environment. The SDHW system located at the Bialystok University of Technology (Poland) was the source of the measurement results used to validate the simulation model. The mathematical optimization procedure showed that the maximum annual useful energy output that can be obtained from 1 m2 of gross collector area is 1303 kWh in the case of Madrid, 918.5 kWh for Budapest, and 768 kWh for Helsinki weather conditions.

FOSSIL FUEL ENVIRONMENTAL CONTAMINATION: A STRATEGY USING RADIOCARBON, N-ALKANES, AND ALGAE

Radiocarbon ◽  
2021 ◽  
pp. 1-9
Author(s):  
Túlio César Aguiar Silva ◽  
Carla Carvalho ◽  
Bruno Libardoni ◽  
Kita Macario ◽  
Felippe Braga de Lima ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Environmental Contamination ◽  
Aquatic Ecosystems ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Maximum Intensity ◽  
Effective Technique ◽  
The World ◽  
Work Samples

ABSTRACT Fossil fuels are of utmost importance to the world we live in today. However, their use can cause major impacts on the environment, especially on water resources. In this regard, algae have been intensively used as a strategy for remediation and monitoring of environmental pollution due to its efficient absorption of contaminants. In this work, samples of seaweed collected in Niterói/RJ—contaminated with kerosene and diesel—were analyzed by radiocarbon (14C) accelerator mass spectrometry (AMS) and by n-alkane quantification with gas chromatography to evaluate bioaccumulation in function of the dosage of contaminants. The biogenic content measured by radiocarbon analysis resulted in 95.6% for algae contaminated with 10 mL of kerosene and 67.6% for algae contaminated with 10 mL of diesel. The maximum intensity of n-C17 n-alkane in algae with 5 mL, 10 mL, and 15 mL of diesel was 768.2, 1878.1, and 5699.2 ng.g-1, respectively. While the maximum concentration of n-C27 in algae with 5 mL, 10 mL and 15 mL of kerosene was 3.3, 35.9, and 150.3 ng.g-1. We concluded that, for both contaminants, their incorporation into algae increases as the contamination dosage increases, making this methodology an effective technique for monitoring and remediation of urban aquatic ecosystems.

scholarly journals Photochemistry of 1-Phenyl-4-Allyl-Tetrazol-5-One: A Theoretical Study Contribution towards Mechanism Elucidation

2021 ◽  
Vol 11 (9) ◽  
pp. 4045
Author(s):  
Amilcar Duque-Prata ◽  
Carlos Serpa ◽  
Pedro J. S. B. Caridade
Keyword(s):  
Density Functional ◽  
Reaction Pathway ◽  
Intramolecular Proton Transfer ◽  
Polarizable Continuum Model ◽  
Uv Spectra ◽  
Point Of View ◽  
Basis Set ◽  
Pathway Evolution ◽  
Photodegradation Mechanism ◽  
Energetic Point

The photodegradation mechanism of 1-phenyl-4-allyl-tetrazol-5-one has been studied using (time-dependent) density functional theory with the M06-HF, B3LYP, and PBE0 functionals and the VDZ basis set. All calculations have been carried out using the polarizable continuum model to simulate the solvent effects of methanol. The reaction pathway evolution on the triplet state has been characterised to validate a previously postulated experimental-based mechanism. The transition states and minimums have been initially located by local scanning in partial constrained optimisation, followed by a fully relaxed search procedure. The UV spectra has shown to be better described with PBE0 functional when compared with the experimental results, having the M06-HF a shift of 40 nm. From the energetic point of view, the postulated mechanism has been validated in this work showing a concerted photoextrusion of the N2 molecule. The intramolecular proton transfer occurs at a later stage of the mechanism after cyclization of the allyl group on a triplet biradical intermediate. The photoproduct observed experimentally, a pyrimidinone, has been characterised. The infrared spectroscopic reaction profile has also been proposed.

Quitting (The) Habit: Fossil Fuels, Governmentality and the Politics of Energy Dependency

2021 ◽  
Vol 103 (103) ◽  
pp. 63-77
Author(s):  
Imre Szeman
Keyword(s):  
Specific Energy ◽  
Fossil Fuels ◽  
Energy Use ◽  
Fossil Fuel ◽  
Daily Life ◽  
Practice Theory ◽  
State Power ◽  
System Change ◽  
Analytic Tool ◽  
Energy Dependency

This paper investigates habit in relation to fossil-fuel dependency. Habit names sets of actions and practices that are deeply codified into daily life, including practices connected to the use of large amounts of energy. Developing an understanding of energy habits appears to constitute a possible site of intervention into the ongoing use of fossil fuels. I argue that by tending to focus on individual energy practices, habit makes it difficult to raise larger, systemic questions related to energy use. Indeed, more critical explorations of habit, such as practice theory or via Bourdieu's notion of habitus, emphasise the need to attend to system more than specific energy habits. Investigating habit in relation to energy does, however, reveal some of the current limits and problems involved in changing fossil-fuel dependency on the part of many states. The paper turns to an investigation of the operations of governmentality in relation to energy to show the multiple ways in which the contemporary configuration of state power makes it unable to fully attend to fossil-fuel dependency. Making small changes to energy use via changes to energy habit never results in the system change required. While habit can thus be a useful analytic tool in understanding state power in relation to energy use, the paper argues that it is not a mechanism through which one might fundamentally change current configurations of energy dependency.

scholarly journals The Use of Urea and Kelp Waste Extract is A Promising Strategy for Maximizing the Biomass Productivity and Lipid Content in Chlorella sorokiniana

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 463 ◽  
Author(s):  
Ali Nawaz Kumbhar ◽  
Meilin He ◽  
Abdul Razzaque Rajper ◽  
Khalil Ahmed Memon ◽  
Muhammad Rizwan ◽  
...  
Keyword(s):  
Lipid Content ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Lipid Production ◽  
Total Lipid Content ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Biofuel Production ◽  
Promising Strategy ◽  
Waste Extract

The decline in fossil fuel reserves has forced researchers to seek out alternatives to fossil fuels. Microalgae are considered to be a promising feedstock for sustainable biofuel production. Previous studies have shown that urea is an important nitrogen source for cell growth and the lipid production of microalgae. The present study investigated the effect of different concentrations of urea combined with kelp waste extract on the biomass and lipid content of Chlorella sorokiniana. The results revealed that the highest cell density, 20.36 × 107 cells−1, and maximal dry biomass, 1.70 g/L, were achieved in the presence of 0.5 g/L of urea combined with 8% kelp waste extract. Similarly, the maximum chlorophyll a, b and beta carotenoid were 10.36 mg/L, 7.05, and 3.01 mg/L, respectively. The highest quantity of carbohydrate content, 290.51 µg/mL, was achieved in the presence of 0.2 g/L of urea and 8% kelp waste extract. The highest fluorescence intensity, 40.05 × 107 cells−1, and maximum total lipid content (30%) were achieved in the presence of 0.1 g/L of urea and 8% kelp waste extract. The current study suggests that the combination of urea and kelp waste extract is the best strategy to enhance the biomass and lipid content in Chlorella sorokiniana.

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