scholarly journals Improving the Combustion Properties of Corncob Biomass via Torrefaction for Solid Fuel Applications

2021 ◽  
Vol 5 (10) ◽  
pp. 260
Author(s):  
Segun Emmanuel Ibitoye ◽  
Tien-Chien Jen ◽  
Rasheedat Modupe Mahamood ◽  
Esther Titilayo Akinlabi
Keyword(s):  
Climate Change ◽  
Residence Time ◽  
Solid Fuel ◽  
Energy Production ◽  
Primary Energy ◽  
Green Energy ◽  
Residence Times ◽  
Heating Value ◽  
Combustion Properties ◽  
Time Lead

The overdependence on fossils as the primary energy source has led to climate change, global warming, and the emission of greenhouse gas. As a result, the United Nations, while setting the goals for the year 2030, has made the provision of a green environment and energy one of the top priorities. In this study, the suitability of corncob for green energy production was investigated. The improvement of corncob’s thermal and combustion properties via the torrefaction process was considered for solid fuel applications. The raw corncob was collected, sorted, and dried for seven days before being used for the torrefaction experiment. Different torrefaction temperatures (200, 240, and 260 °C) and residence times (20, 40, 60 min) were studied. There was no particle reduction—samples were torrefied as collected (whole corncob). The results show that torrefaction temperature and residence time affect the torrefaction products yields along with their properties. Thermal and combustion properties were improved with an increase in torrefaction temperature and residence time. The higher heating value and energy density of the torrefied corncob varied between 17.26 and 18.89 MJ/kg, and 3.23 and 5.66 GJ/m3, respectively. High torrefaction temperature and residence time lead to low solid yield; however, liquid and gas yields increase with torrefaction temperature and residence time. The solid yields varied from 27.57 to 52.23%, while the liquid and gas yields varied from 31.56 to 44.78% and 16.21 to 27.65%, respectively. The properties of corncob improve after torrefaction and are suitable for solid fuel application.

scholarly journals Biochar produced from poultry litter waste

2021 ◽  
Vol 10 (11) ◽  
pp. e351101119704
Author(s):  
Moisés Edevaldo Pereira ◽  
Luciano Donizeti Varanda ◽  
Natália Rodrigues de Carvalho ◽  
Carlos Roberto Sette Jr ◽  
Franciane Andrade de Padua ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Residence Time ◽  
Broiler Chickens ◽  
Poultry Litter ◽  
Proximate Analysis ◽  
Ash Content ◽  
Residence Times ◽  
Heating Value ◽  
Scanning Electron

Brazil generates substantial quantity of poultry litter waste because of its worldwide prominence in the production of broiler chickens. The volume of the poultry litter biomass generates considerable environmental impact. The objective was to characterize the biochar produced from poultry litter residue under different conditions with the aim of determining the best residence time and temperature. Poultry litter was collected after two batches of chicken breeding. Five treatments for biochar production were carried out at a temperature of 450 °C (defined by thermogravimetric analysis - TGA) and residence times of 0.5, 1, 2, 4, and 6h. The biochar produced was assessed using proximate analysis, moisture content, gravimetric yield, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and HHV (higher heating value). The results revealed that the best conditions for biochar production was 450 °C (pyrolysis) and residence time of 0.5h, with 37.21% gravimetric yield. We concluded that the biochar produced in this study is recommended for soil application but was not suitable for energy purposes because of its high ash content (up to 33.66%) and low HHV (18,907 J g-1).

scholarly journals Is the biochar produced from sewage sludge a good quality solid fuel?

2016 ◽  
Vol 42 (4) ◽  
pp. 125-134 ◽  
Author(s):  
Jakub Pulka ◽  
Dariusz Wiśniewski ◽  
Janusz Gołaszewski ◽  
Andrzej Białowiec
Keyword(s):  
Sewage Sludge ◽  
Temperature Profile ◽  
Sulfur Content ◽  
Residence Time ◽  
Solid Fuel ◽  
Initial Energy ◽  
Lignocellulosic Waste ◽  
Fuel Production ◽  
Heating Value ◽  
Treatment Experiment

Abstract The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.

scholarly journals Wind Farm Cable Connection Layout Optimization with Several Substations

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3615
Author(s):  
Adelaide Cerveira ◽  
Eduardo J. Solteiro Pires ◽  
José Baptista
Keyword(s):  
Energy Production ◽  
Wind Farm ◽  
Programming Model ◽  
Optimal Solution ◽  
Wind Farms ◽  
Green Energy ◽  
Fossil Energy ◽  
Proposed Model ◽  
Short Time ◽  
Cable Connection

Green energy has become a media issue due to climate changes, and consequently, the population has become more aware of pollution. Wind farms are an essential energy production alternative to fossil energy. The incentive to produce wind energy was a government policy some decades ago to decrease carbon emissions. In recent decades, wind farms were formed by a substation and a couple of turbines. Nowadays, wind farms are designed with hundreds of turbines requiring more than one substation. This paper formulates an integer linear programming model to design wind farms’ cable layout with several turbines. The proposed model obtains the optimal solution considering different cable types, infrastructure costs, and energy losses. An additional constraint was considered to limit the number of cables that cross a walkway, i.e., the number of connections between a set of wind turbines and the remaining wind farm. Furthermore, considering a discrete set of possible turbine locations, the model allows identifying those that should be present in the optimal solution, thereby addressing the optimal location of the substation(s) in the wind farm. The paper illustrates solutions and the associated costs of two wind farms, with up to 102 turbines and three substations in the optimal solution, selected among sixteen possible places. The optimal solutions are obtained in a short time.

scholarly journals Experimental and Numerical Study of a Microcogeneration Stirling Unit under On–Off Cycling Operation

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 801
Author(s):  
Gianluca Valenti ◽  
Aldo Bischi ◽  
Stefano Campanari ◽  
Paolo Silva ◽  
Antonino Ravidà ◽  
...  
Keyword(s):  
Numerical Study ◽  
Thermal Storage ◽  
Primary Energy ◽  
Operational Cost ◽  
Cogeneration Plant ◽  
Economic Optimization ◽  
Viable Option ◽  
Heating Value ◽  
Energy Flows

Stirling units are a viable option for micro-cogeneration applications, but they operate often with multiple daily startups and shutdowns due to the variability of load profiles. This work focused on the experimental and numerical study of a small-size commercial Stirling unit when subjected to cycling operations. First, experimental data about energy flows and emissions were collected during on–off operations. Second, these data were utilized to tune an in-house code for the economic optimization of cogeneration plant scheduling. Lastly, the tuned code was applied to a case study of a residential flat in Northern Italy during a typical winter day to investigate the optimal scheduling of the Stirling unit equipped with a thermal storage tank of diverse sizes. Experimentally, the Stirling unit showed an integrated electric efficiency of 8.9% (8.0%) and thermal efficiency of 91.0% (82.2%), referred to as the fuel lower and, between parenthesis, higher heating value during the on–off cycling test, while emissions showed peaks in NOx and CO up to 100 ppm but shorter than a minute. Numerically, predictions indicated that considering the on–off effects, the optimized operating strategy led to a great reduction of daily startups, with a number lower than 10 per day due to an optimal thermal storage size of 4 kWh. Ultimately, the primary energy saving was 12% and the daily operational cost was 2.9 €/day.

scholarly journals Effect of bathymetric changes on residence time in Buenaventura bay (Colombia)

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 241-248
Author(s):  
Francisco Fernando Garcia Renteria ◽  
Mariela Patricia Gonzalez Chirino
Keyword(s):  
Finite Elements ◽  
Residence Time ◽  
Particle Tracking ◽  
Hydrodynamic Model ◽  
Residence Times ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Bathymetric Changes

In order to study the effects of dredging on the residence time of the water in Buenaventura Bay, a 2D finite elements hydrodynamic model was coupled with a particle tracking model. After calibrating and validating the hydrodynamic model, two scenarios that represented the bathymetric changes generated by the dredging process were simulated. The results of the comparison of the simulated scenarios, showed an important reduction in the velocities fields that allow an increase of the residence time up to 12 days in some areas of the bay. In the scenario without dredging, that is, with original bathymetry, residence times of up to 89 days were found.

Robotics Application in Remote Data Acquisition and Control for Solar Ponds

2012 ◽  
Vol 253-255 ◽  
pp. 705-715 ◽  
Author(s):  
Mohamed Elbanhawi ◽  
Milan Simic
Keyword(s):  
Data Acquisition ◽  
Real Time ◽  
Energy Production ◽  
Green Energy ◽  
Industrial Robots ◽  
Sampling Station ◽  
Monitoring And Control ◽  
Solar Ponds ◽  
And Control ◽  
Remote Data

This paper presents one application of industrial robots in the automation of renewable energy production. The robot supports remote performance monitoring and maintenance of salinity gradient solar ponds. The details of the design, setup and the use of the robot sampling station and the remote Data Acquisition (DAQ) system are given here. The use of a robot arm, to position equipment and sensors, provides accurate and reliable real time data needed for autonomous monitoring and control of this type of green energy production. Robot upgrade of solar ponds can be easily integrated with existing systems. Data logged by the proposed system can be remotely accessed, plotted and analysed. Thus the simultaneous and remote monitoring of a large scale network of ponds can be easily implemented. This provides a fully automated solution to the monitoring and control of green energy production operations, which can be used to provide heat and electricity to buildings. Remote real time monitoring will facilitate the setup and operations of several solar ponds around cities.

Flow pattern and residence time of conduit flow and diffuse flow in calcareous sandstones (Bohemian Cretaceous Basin, Czech Republic)

2021 ◽  
Author(s):  
Iva Kůrková ◽  
Jiří Bruthans
Keyword(s):  
Czech Republic ◽  
Groundwater Flow ◽  
Residence Time ◽  
Dispersion Model ◽  
Tracer Tests ◽  
Water Levels ◽  
Northwestern Part ◽  
Residence Times ◽  
Karst Springs ◽  
Bohemian Cretaceous Basin

<p>Localities containing karst features were studied in the northwestern part of Bohemian Cretaceous Basin. Namely Turnov area in facies transition between coarse-delta sandstones and marlstones (Jizera Formation, Turonian) and Miskovice area in limestones and sandy limestones - sandstones (Peruc-Korycany Formation, Cenomanian). Evolution of karst conduits is discussed elsewhere (Kůrková et al. 2019).</p><p>In both localities, disappearing streams, caves and karst springs with maximum discharge up to 100 L/s were documented. Geology and hydrogeology of this area was studied from many points of view to describe formation of karst conduits and characterize groundwater flow. Tracer tests were performed using NaCl and Na-fluoresceine between sinkholes and springs under various flow rates to evaluate residence times of water in conduits and to describe geometry of conduits. Breatkthrough curves of tracer tests were evaluated by means of Qtracer2 program (Field 2002). Groundwater flow velocity in channels starts at 0.6 km/day during low water levels up to 15 km/day during maximum water levels, the velocity increases logarithmically as a function of discharge. Similar karst conduits probably occur in other parts of Bohemian Cretaceous Basin where lot of large springs can be found.</p><p>Mean residence time of difussed flow based on tritium, CFC and SF<sub>6</sub> sampled at karst springs is 20 years for 75% of water and 100 years for remaining 25%, based on binary mixing dispersion model. This shows that most of the water drained by karst conduits is infiltrated through the soil and fractured environment with relatively high residence time. Residence times in different types of wells and springs were also measured in whole north-western part of Bohemian Cretaceous Basin. Results indicate long residence times in semi-stagnant zones represented by monitoring wells and short residence times in preferential zones represented by springs and water-supply wells.</p><p> </p><p>Research was funded by the Czech Science Foundation (GA CR No. 19-14082S), Czech Geological Survey – internal project 310250</p><p> </p><p>Field M. (2002): The QTRACER2 program for Tracer Breakthrough Curve Analysis for Tracer Tests in Karstic Aquifers and Other hydrologic Systems. – U.S. Environmental protection agency hypertext multimedia publication in the Internet at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=54930.</p><p>Kůrková I., Bruthans J., Balák F., Slavík M., Schweigstillová J., Bruthansová J., Mikuš P., Grundloch J. (2019): Factors controlling evolution of karst conduits in sandy limestone and calcareous sandstone (Turnov area, Czech Republic). Journal of Hydrology: 574: 1062-1073</p>

scholarly journals Alan Betts: Green Energy Times, 2018

2019 ◽  
Author(s):  
Alan Betts
Keyword(s):  
Climate Change ◽  
Energy Policy ◽  
Climate Science ◽  
Green Energy ◽  
Collective Decision ◽  
The Public ◽  
Systems Perspective ◽  
Climate Change Denial ◽  
The Earth ◽  
The Future

This is a collection of my 2018 articles in the Green Energy Times (http://www.greenenergytimes.org/ ).This series started in 2016. Many of these articles have been edited or updated from articles I wrote forthe Rutland Herald, sometimes with different titles and pictures.They blend science and opinion with a systems perspective, and encourage the reader to explorealternative and hopeful paths for their families and society. They are written so that a scientist willperceive them as accurate (although simplified); while the public can relate their tangible experience ofweather and climate to the much less tangible issues of climate change, energy policy and strategies forliving sustainably with the earth system.The politically motivated attacks on climate science by the current president have sharpened my politicalcommentary this year; since climate change denial may bring immense suffering to our children and lifeon Earth.I believe that earth scientists have a responsibility to communicate clearly and directly to the public1 –aswe all share responsibility for the future of the Earth. We must deepen our collective understanding, sowe can make a collective decision to build a resilient future.

scholarly journals A short history of climate change

2020 ◽  
Vol 246 ◽  
pp. 00002
Author(s):  
Dirk Notz
Keyword(s):  
Climate Change ◽  
Energy Production ◽  
Short History ◽  
Unique Challenge ◽  
Climate Conditions ◽  
The Earth ◽  
Two Factors ◽  
History Of ◽  
Natural Climate ◽  
First Time

The flux of energy through the climate system determines the living conditions of our planet. In this contribution, I outline the main processes regulating this flux of energy, how these processes have changed throughout Earth history, and how today they are changing by human activities, in particular by activities related to energy production. The changes in the climate state of our planet, which have been ongoing ever since the formation of the Earth some 5 billion years ago, have shaped the world we live in today. Yet, today’s climate change is special in two overarching ways. First, it is the first time that a major climate change is globally affecting a civilisation that is perfectly adapted to thousands of years of stable climate conditions. Second, today’s climate change is occurring at a rate much faster than preceding natural climate changes. In combination, these two factors make today’s climate change a unique challenge to humankind, with direct consequences of future energy production as outlined in the other contributions to this volume.

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