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Energies, Volume 6, Issue 3 (March 2013), Pages 1181-1801

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Open AccessArticle Production of Bioethanol from Carrot Pomace Using the Thermotolerant Yeast Kluyveromyces marxianus
Energies 2013, 6(3), 1794-1801; https://doi.org/10.3390/en6031794
Received: 8 October 2012 / Revised: 20 December 2012 / Accepted: 8 March 2013 / Published: 21 March 2013
Cited by 7 | PDF Full-text (357 KB) | HTML Full-text | XML Full-text
Abstract
Carrot pomace, a major agricultural waste from the juice industry, was used as a feedstock for bioethanol production by fermentation with the thermotolerant yeast Kluyveromyces marxianus. Treatment of the carrot pomace with AccelleraseTM 1000 and pectinase at 50 °C for 84
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Carrot pomace, a major agricultural waste from the juice industry, was used as a feedstock for bioethanol production by fermentation with the thermotolerant yeast Kluyveromyces marxianus. Treatment of the carrot pomace with AccelleraseTM 1000 and pectinase at 50 °C for 84 h, resulted in conversion of 42% of its mass to fermentable sugars, mainly glucose, fructose, and sucrose. Simultaneous saccharification and fermentation (SSF) at 42 °C was performed on 10% (w/v) carrot pomace; the concentration of ethanol reached 18 g/L and the yield of ethanol from carrot pomace was 0.18 g/g. The highest ethanol concentration of 37 g/L was observed with an additional charge of 10% supplemented to the original 10% of carrot pomace after 12 h; the corresponding yield was 0.185 g/g. Our results clearly demonstrated the potential of combining a SSF process with thermotolerant yeast for the production of bioethanol using carrot pomace as a feedstock. Full article
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Open AccessArticle Efficiency of Edible Agriculture in Canada and the U.S. Over the Past Three and Four Decades
Energies 2013, 6(3), 1764-1793; https://doi.org/10.3390/en6031764
Received: 17 January 2013 / Revised: 7 March 2013 / Accepted: 8 March 2013 / Published: 19 March 2013
Cited by 17 | PDF Full-text (398 KB) | HTML Full-text | XML Full-text
Abstract
We examine technological progress in the US and Canada to answer the question: has the efficiency (e.g., the edible energy efficiency, or EEE) for producing agricultural products in the US and Canada increased in recent decades? Specifically, we determined the energy efficiency of
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We examine technological progress in the US and Canada to answer the question: has the efficiency (e.g., the edible energy efficiency, or EEE) for producing agricultural products in the US and Canada increased in recent decades? Specifically, we determined the energy efficiency of agriculture at the farm gate in recent decades by dividing the outputs (the total annual crop and animal output in energy units minus the feed used for animal production and the grain used for ethanol production) by the energy inputs: all the energy used by the nation to produce food (the energy used to generate and apply the fertilizer, pesticides, seed and to operate machinery) minus the energy inputs to produce grain for ethanol. Our data comes primarily from national and international agricultural censuses. Our study found that the energy efficiency of US agriculture has more than doubled from 0.8:1 in 1970 to 2.2:1 by 2000, then increased more slowly to 2.3:1 by 2009. The energy efficiency of the agricultural sector in Canada has not changed appreciably since 1980, and has varied about a mean of 2:1 from 1981 to 2009. Our study found that EEE improvements in the US could be attributable in part to advancements in crop production per hectare, and lower direct fuel consumption, but also a greater proportion of less energy-intensive corn and changes to the diet of livestock (e.g., increased use of meals and other by-products which have increased the availability of grain). Thus increases due to technological progress alone for the last several decades appear small, less than one percent a year. Full article
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Open AccessArticle Intake Manifold Boosting of Turbocharged Spark-Ignited Engines
Energies 2013, 6(3), 1746-1763; https://doi.org/10.3390/en6031746
Received: 5 February 2013 / Revised: 5 March 2013 / Accepted: 8 March 2013 / Published: 13 March 2013
Cited by 4 | PDF Full-text (514 KB) | HTML Full-text | XML Full-text
Abstract
Downsizing and turbocharging is a widely used approach to reduce the fuel consumption of spark ignited engines while retaining the maximum power output. However, a substantial loss in drivability must be expected due to the occurrence of the so-called turbo lag. The turbo
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Downsizing and turbocharging is a widely used approach to reduce the fuel consumption of spark ignited engines while retaining the maximum power output. However, a substantial loss in drivability must be expected due to the occurrence of the so-called turbo lag. The turbo lag results from the additional inertia that the turbocharger adds to the system. Supplying air by an additional valve, the boost valve, to the intake manifold can be used to overcome the turbo lag. This turbo lag compensationmethod is referred to as intakemanifold boosting. The aims of this study are to show the effectiveness of intake manifold boosting on a turbocharged spark-ignited engine and to show that intake manifold boosting can be used as an enabler of strong downsizing. Guidelines for the dimensioning of the boost valve are given and a control strategy is presented. The trade-off between additional fuel consumption and the consumption of pressurized air during the turbo lag compensation is discussed. For a load step at 2000 rpm the rise time can be reduced from 2.8 s to 124ms, requiring 11.8 g of pressurized air. The transient performance is verified experimentally by means of load steps at various engine speeds to various engine loads. Full article
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Open AccessArticle Experimental Investigation on the Performance of a Compressed-Air Driven Piston Engine
Energies 2013, 6(3), 1731-1745; https://doi.org/10.3390/en6031731
Received: 3 December 2012 / Revised: 7 March 2013 / Accepted: 8 March 2013 / Published: 12 March 2013
Cited by 25 | PDF Full-text (1548 KB) | HTML Full-text | XML Full-text
Abstract
This study presents an experimental investigation of a piston engine driven by compressed air. The compressed air engine was a modified 100 cm3 internal combustion engine obtained from a motorcycle manufacturer. The experiments in this study used a test bench to examine
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This study presents an experimental investigation of a piston engine driven by compressed air. The compressed air engine was a modified 100 cm3 internal combustion engine obtained from a motorcycle manufacturer. The experiments in this study used a test bench to examine the power performance and pressure/temperature variations of the compressed air engine at pressures ranging from 5 to 9 bar (absolute pressure). The engine was modified from a 4-stroke to a 2-stroke engine using a cam system driven by a crankshaft and the intake and exhaust valves have a small lift due to this modification. The highest power output of 0.95 kW was obtained at 9 bar and 1320 rpm. The highest torque of 9.99 N·m occurred at the same pressure, but at 465 rpm. The pressure-volume (P-V) diagram shows that cylinder pressure gradually increases after the intake valve opens because of the limited lift movement of the intake valve. Similar situations occurred during the exhaust process, restricting the power output of the compressed air engine. The pressure and temperature variation of the air at engine inlet and outlet were recorded during the experiment. The outlet pressure increased from 1.5 bar at 500 rpm to 2.25 bar at 2000 rpm, showing the potential of recycling the compressed air energy by attaching additional cylinders (split-cycle engine). A temperature decrease (from room temperature to 17 °C) inside the cylinder was observed. It should be noted that pressures higher than that currently employed can result in lower temperatures and this can cause poor lubrication and sealing issues. The current design of a compressed air engine, which uses a conventional cam mechanism for intake and exhaust, has limited lift movement during operation, and has a restricted flow rate and power output. Fast valve actuation and a large lift are essential for improving the performance of the current compressed air engine. This study presents a power output examination with the pressure and temperature measurements of a piston-type compressed air engine to be installed in compact vehicles as the main or auxiliary power system. Full article
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Open AccessReview Preparation and Doping Mode of Doped LiMn2O4 for Li-Ion Batteries
Energies 2013, 6(3), 1718-1730; https://doi.org/10.3390/en6031718
Received: 5 January 2013 / Revised: 2 March 2013 / Accepted: 6 March 2013 / Published: 12 March 2013
Cited by 39 | PDF Full-text (246 KB) | HTML Full-text | XML Full-text
Abstract
Spinel LiMn2O4 is an appealing candidate cathode material for Li-ion rechargeable batteries, but itsuffers from severe capacity fading, especially at higher temperature (55 °C) during discharging/charging. In recent years, many attempts have been made to synthesize modified LiMn2
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Spinel LiMn2O4 is an appealing candidate cathode material for Li-ion rechargeable batteries, but it suffers from severe capacity fading, especially at higher temperature (55 °C) during discharging/charging. In recent years, many attempts have been made to synthesize modified LiMn2O4. This paper reviews the recent research on the preparation and doping modes of doped LiMn2O4 for modifying the LiMn2O4. We firstly compared preparation methods for doped spinel LiMn2O4, such as solid state reactions and solution synthetic methods. Then we mainly discuss doping modes reported in recent years, such as bulk doping, surface doping and combined doping. A comparison of different doping modes is also provided. The research shows that the multiple-ion doping and combined doping modes of LiMn2O4 used in Li-ion battery are excellent for improving different aspects of the electrochemical performance which holds great promise in the future. From this paper, we also can see that spinel LiMnO4 as an attractive candidate cathode material for Li-ion batteries. Full article
(This article belongs to the Special Issue Li-ion Batteries and Energy Storage Devices)
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Open AccessArticle Mitigation of Asymmetrical Grid Faults in Induction Generator-Based Wind Turbines Using Constant Power Load
Energies 2013, 6(3), 1700-1717; https://doi.org/10.3390/en6031700
Received: 11 October 2012 / Revised: 24 January 2013 / Accepted: 27 February 2013 / Published: 12 March 2013
Cited by 3 | PDF Full-text (515 KB) | HTML Full-text | XML Full-text
Abstract
Constant power loads (CPLs), interfaced through active rectifiers can be used for improving the stability of induction generator (IG)-based wind turbines under balanced grid voltage dips by providing the reactive power. Under asymmetrical grid faults, the negative sequence voltage produces additional generator torque
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Constant power loads (CPLs), interfaced through active rectifiers can be used for improving the stability of induction generator (IG)-based wind turbines under balanced grid voltage dips by providing the reactive power. Under asymmetrical grid faults, the negative sequence voltage produces additional generator torque oscillations and reduces the lifetime of the installed equipment. This article explores the possibility of using a CPL for mitigation of unbalanced voltage dips in an AC distribution system in addition to consuming a constant active power. Unbalanced fault mitigation as an ancillary service by the load itself could greatly increase the stability and performance of the overall power system. A CPL control structure, capable of controlling the positive and negative sequence of the grid voltage is suggested. The simulation results clearly indicate the effects of compensating the positive and negative sequence of the grid voltage on the performance of IG based wind turbines. The maximum Fault Ride Through (FRT) enhancement has been given priority and is done by the compensation of positive sequence voltage. The remaining CPL current capacity is used to compensate the negative sequence voltage in order to reduce the additional torque ripples in the IG. Full article
(This article belongs to the Special Issue Smart Grid and the Future Electrical Network)
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Open AccessArticle Li-Ion Battery Charging with a Buck-Boost Power Converter for a Solar Powered Battery Management System
Energies 2013, 6(3), 1669-1699; https://doi.org/10.3390/en6031669
Received: 26 November 2012 / Revised: 16 February 2013 / Accepted: 5 March 2013 / Published: 11 March 2013
Cited by 12 | PDF Full-text (1970 KB) | HTML Full-text | XML Full-text
Abstract
This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage
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This paper analyzes and simulates the Li-ion battery charging process for a solar powered battery management system. The battery is charged using a non-inverting synchronous buck-boost DC/DC power converter. The system operates in buck, buck-boost, or boost mode, according to the supply voltage conditions from the solar panels. Rapid changes in atmospheric conditions or sunlight incident angle cause supply voltage variations. This study develops an electrochemical-based equivalent circuit model for a Li-ion battery. A dynamic model for the battery charging process is then constructed based on the Li-ion battery electrochemical model and the buck-boost power converter dynamic model. The battery charging process forms a system with multiple interconnections. Characteristics, including battery charging system stability margins for each individual operating mode, are analyzed and discussed. Because of supply voltage variation, the system can switch between buck, buck-boost, and boost modes. The system is modeled as a Markov jump system to evaluate the mean square stability of the system. The MATLAB based Simulink piecewise linear electric circuit simulation tool is used to verify the battery charging model. Full article
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Open AccessCommunication A Demonstration of Carbon-Assisted Water Electrolysis
Energies 2013, 6(3), 1657-1668; https://doi.org/10.3390/en6031657
Received: 19 December 2012 / Revised: 22 February 2013 / Accepted: 5 March 2013 / Published: 11 March 2013
Cited by 11 | PDF Full-text (298 KB) | HTML Full-text | XML Full-text
Abstract
It is shown that carbon fuel cell technology can be combined with that of high temperature steam electrolysis by the incorporation of carbon fuel at the cell anode, with the resulting reduction of the required electrolysis voltage by around 1 V. The behaviour
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It is shown that carbon fuel cell technology can be combined with that of high temperature steam electrolysis by the incorporation of carbon fuel at the cell anode, with the resulting reduction of the required electrolysis voltage by around 1 V. The behaviour of the cell current density and applied voltage are shown to be connected with the threshold of electrolysis and the main features are compared with theoretical results from the literature. The advantage arises from the avoidance of efficiency losses associated with electricity generation using thermal cycles, as well as the natural separation of the carbon dioxide product stream for subsequent processing. Full article
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Open AccessArticle Percolation Theory in Solid Oxide Fuel Cell Composite Electrodes with a Mixed Electronic and Ionic Conductor
Energies 2013, 6(3), 1632-1656; https://doi.org/10.3390/en6031632
Received: 6 December 2012 / Revised: 26 February 2013 / Accepted: 6 March 2013 / Published: 11 March 2013
Cited by 12 | PDF Full-text (1698 KB) | HTML Full-text | XML Full-text
Abstract
Percolation theory is generalized to predict the effective properties of specific solid oxide fuel cell composite electrodes, which consist of a pure ion conducting material (e.g., YSZ or GDC) and a mixed electron and ion conducting material (e.g., LSCF, LSCM or CeO2
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Percolation theory is generalized to predict the effective properties of specific solid oxide fuel cell composite electrodes, which consist of a pure ion conducting material (e.g., YSZ or GDC) and a mixed electron and ion conducting material (e.g., LSCF, LSCM or CeO2). The investigated properties include the probabilities of an LSCF particle belonging to the electron and ion conducting paths, percolated three-phase-boundary electrochemical reaction sites, which are based on different assumptions, the exposed LSCF surface electrochemical reaction sites and the revised expressions for the inter-particle ionic conductivities among LSCF and YSZ materials. The effects of the microstructure parameters, such as the volume fraction of the LSCF material, the particle size distributions of both the LSCF and YSZ materials (i.e., the mean particle radii and the non-dimensional standard deviations, which represent the particle size distributions) and the porosity are studied. Finally, all of the calculated results are presented in non-dimensional forms to provide generality for practical application. Based on these results, the relevant properties can be easily evaluated, and the microstructure parameters and intrinsic properties of each material are specified. Full article
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Open AccessArticle Dried Spent Yeast and Its Hydrolysate as Nitrogen Supplements for Single Batch and Repeated-Batch Ethanol Fermentation from Sweet Sorghum Juice
Energies 2013, 6(3), 1618-1631; https://doi.org/10.3390/en6031618
Received: 2 October 2012 / Revised: 18 February 2013 / Accepted: 25 February 2013 / Published: 11 March 2013
Cited by 4 | PDF Full-text (267 KB) | HTML Full-text | XML Full-text
Abstract
Dried spent yeast (DSY) and its hydrolysate (DSYH) were used as low-cost nitrogen supplements to improve ethanol production from sweet sorghum juice by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation (280 g·L−1 of total sugar) conditions. The supplemented DSY and
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Dried spent yeast (DSY) and its hydrolysate (DSYH) were used as low-cost nitrogen supplements to improve ethanol production from sweet sorghum juice by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation (280 g·L−1 of total sugar) conditions. The supplemented DSY and DSYH concentrations were 11, 16 and 21 g·L−1, corresponding to a yeast extract nitrogen content of 6, 9 and 12 g·L−1, respectively. The initial yeast cell concentration for ethanol fermentation was approximately 5 × 107 cells·mL−1. The fermentation was carried out in single batch mode at 30 °C in 1-L air-locked bottles with an agitation rate of 100 rpm. Ethanol production from the juice with and without yeast extract (9 g·L−1) was also performed as control treatments. The results showed that DSY at 21 g·L−1gave the highest ethanol concentration (PE, 107 g·L−1) and yield (Yp/s, 0.47 g·g−1). The use of DSYH at the same DSY concentration improved ethanol productivity (Qp), but not PE and Yp/s. The ethanol production efficiencies of the juice under DSY and DSYH supplementations were markedly higher than those without nutrient supplementation. However, the PE and Qp values of the juice containing 21 g·L−1 of DSY was approximately 7 g·L−1 and 0.62 g·L−1·h−1 lower than those under the presence of yeast extract (9 g·L−1), respectively. At the end of the single batch fermentation under the optimum DSY concentration, the sugar consumption was approximately 80%. Therefore in the repeated-batch fermentation, the initial total sugar was reduced to 240 g·L−1. The results showed that the system could be carried out at least 20 successive batches with the average PE, Yp/s and Qp of 95 g·L−1, 0.46 g·g−1 and 1.45 g·L−1·h−1, respectively. Full article
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Open AccessArticle Impact of Furfural on Rapid Ethanol Production Using a Membrane Bioreactor
Energies 2013, 6(3), 1604-1617; https://doi.org/10.3390/en6031604
Received: 9 January 2013 / Revised: 26 February 2013 / Accepted: 1 March 2013 / Published: 11 March 2013
Cited by 15 | PDF Full-text (444 KB) | HTML Full-text | XML Full-text
Abstract
A membrane bioreactor was developed to counteract the inhibition effect of furfural in ethanol production. Furfural, a major inhibitor in lignocellulosic hydrolyzates, is a highly toxic substance which is formed from pentose sugars released during the acidic degradation of lignocellulosic materials. Continuous cultivations
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A membrane bioreactor was developed to counteract the inhibition effect of furfural in ethanol production. Furfural, a major inhibitor in lignocellulosic hydrolyzates, is a highly toxic substance which is formed from pentose sugars released during the acidic degradation of lignocellulosic materials. Continuous cultivations with complete cell retention were performed at a high dilution rate of 0.5 h−1. Furfural was added directly into the bioreactor by pulse injection or by addition into the feed medium to obtain furfural concentrations ranging from 0.1 to 21.8 g L−1. At all pulse injections of furfural, the yeast was able to convert the furfural very rapidly by in situ detoxification. When injecting 21.8 g L−1 furfural to the cultivation, the yeast converted it by a specific conversion rate of 0.35 g g−1 h−1. At high cell density, Saccharomyces cerevisiae could tolerate very high furfural levels without major changes in the ethanol production. During the continuous cultures when up to 17.0 g L−1 furfural was added to the inlet medium, the yeast successfully produced ethanol, whereas an increase of furfural to 18.6 and 20.6 g L−1 resulted in a rapidly decreasing ethanol production and accumulation of sugars in the permeate. This study show that continuous ethanol fermentations by total cell retention in a membrane bioreactor has a high furfural tolerance and can conduct rapid in situ detoxification of medium containing high furfural concentrations. Full article
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Open AccessArticle Understanding the Mechanism of Cypress Liquefaction in Hot-Compressed Water through Characterization of Solid Residues
Energies 2013, 6(3), 1590-1603; https://doi.org/10.3390/en6031590
Received: 26 November 2012 / Revised: 4 February 2013 / Accepted: 28 February 2013 / Published: 11 March 2013
Cited by 27 | PDF Full-text (360 KB) | HTML Full-text | XML Full-text
Abstract
The mechanism of hydrothermal liquefaction of cypress was investigated by examining the effects of temperature and retention time on the characteristics of the solid residues remaining after liquefaction. The solid residues were divided into acid-soluble and acid-insoluble residues. Results showed the polymerization reactions
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The mechanism of hydrothermal liquefaction of cypress was investigated by examining the effects of temperature and retention time on the characteristics of the solid residues remaining after liquefaction. The solid residues were divided into acid-soluble and acid-insoluble residues. Results showed the polymerization reactions also mainly occurred at low temperatures. The reactive fragments transformed into acid-insoluble solid residue in the form of carbon and oxygen through polymerization reactions. The process of cellulose degradation consists of two steps: an initial hydrolysis of the more solvent- accessible amorphous region and a later hydrolytic attack on the crystalline portion. Hemicelluloses were decomposed into small compounds during the initial stage of the cypress liquefaction process, and then these compounds may rearrange through polymerization to form acid-insoluble solid residues above 240 °C. The higher heating value of the solid residues obtained from liquefaction at 260–300 °C was 23.4–26.3 MJ/kg, indicating that they were suitable for combustion as a solid fuel. Full article
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Open AccessArticle Catalytic Upgrading of Bio-Oil by Reacting with Olefins and Alcohols over Solid Acids: Reaction Paths via Model Compound Studies
Energies 2013, 6(3), 1568-1589; https://doi.org/10.3390/en6031568
Received: 5 January 2013 / Revised: 1 February 2013 / Accepted: 26 February 2013 / Published: 11 March 2013
Cited by 12 | PDF Full-text (338 KB) | HTML Full-text | XML Full-text
Abstract
Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. Reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol) were studied at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid
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Catalytic refining of bio-oil by reacting with olefin/alcohol over solid acids can convert bio-oil to oxygen-containing fuels. Reactivities of groups of compounds typically present in bio-oil with 1-octene (or 1-butanol) were studied at 120 °C/3 h over Dowex50WX2, Amberlyst15, Amberlyst36, silica sulfuric acid (SSA) and Cs2.5H0.5PW12O40 supported on K10 clay (Cs2.5/K10, 30 wt. %). These compounds include phenol, water, acetic acid, acetaldehyde, hydroxyacetone, d-glucose and 2-hydroxymethylfuran. Mechanisms for the overall conversions were proposed. Other olefins (1,7-octadiene, cyclohexene, and 2,4,4-trimethylpentene) and alcohols (iso-butanol) with different activities were also investigated. All the olefins and alcohols used were effective but produced varying product selectivities. A complex model bio-oil, synthesized by mixing all the above-stated model compounds, was refined under similar conditions to test the catalyst’s activity. SSA shows the highest hydrothermal stability. Cs2.5/K10 lost most of its activity. A global reaction pathway is outlined. Simultaneous and competing esterification, etherfication, acetal formation, hydration, isomerization and other equilibria were involved. Synergistic interactions among reactants and products were determined. Acid-catalyzed olefin hydration removed water and drove the esterification and acetal formation equilibria toward ester and acetal products. Full article
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Open AccessArticle A Novel Pumped Hydro Combined with Compressed Air Energy Storage System
Energies 2013, 6(3), 1554-1567; https://doi.org/10.3390/en6031554
Received: 21 December 2012 / Revised: 10 February 2013 / Accepted: 18 February 2013 / Published: 11 March 2013
Cited by 14 | PDF Full-text (1079 KB) | HTML Full-text | XML Full-text
Abstract
A novel pumped hydro combined with compressed air energy storage (PHCA) system is proposed in this paper to resolve the problems of bulk energy storage in the wind power generation industry over an area in China, which is characterised by drought and water
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A novel pumped hydro combined with compressed air energy storage (PHCA) system is proposed in this paper to resolve the problems of bulk energy storage in the wind power generation industry over an area in China, which is characterised by drought and water shortages. Thermodynamic analysis of the energy storage system, which focuses on the pre-set pressure, storage volume capacity, water air volume ratio, pump performance, and water turbine performance of the storage system, is also presented. This paper discovers how such parameters affect the performance of the whole system. The ideal performance of this novel system has the following advantages: a simple, highly effective and low cost structure, which is comparable to the efficiency of a traditional pumped hydro storage system. Research results show a great solution to the current storage constraints encountered in the development of the wind power industry in China, which have been widely recognised as a bottleneck in the wind energy storage industry. Full article
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Open AccessArticle Analysis and Performance Comparison of Different Power Conditioning Systems for SMES-Based Energy Systems in Wind Turbines
Energies 2013, 6(3), 1527-1553; https://doi.org/10.3390/en6031527
Received: 20 November 2012 / Revised: 19 February 2013 / Accepted: 1 March 2013 / Published: 6 March 2013
Cited by 8 | PDF Full-text (718 KB) | HTML Full-text | XML Full-text
Abstract
Suitability of energy systems based on Superconducting Magnetic Energy Storage (SMES) has been widely tested in the field of wind energy, being able to supply power in cases such as low wind speeds or voltage dips, and to store energy when there are
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Suitability of energy systems based on Superconducting Magnetic Energy Storage (SMES) has been widely tested in the field of wind energy, being able to supply power in cases such as low wind speeds or voltage dips, and to store energy when there are surpluses. This article analyzes and compares the performance of three SMES-based systems that differ in the topology of power converter: a two-level Voltage Source Converter (VSC), a three-level VSC and a two-level Current Source Converter (CSC). Their performance has been improved by means of an appropriate modulation strategy. To obtain a high reliability and accuracy, a co-simulation between MATLAB/Simulink® (running the control system) and PSIM® (running the power system) has been executed. Full article
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