The demand for petroleum has been rising rapidly due to increasing industrialization and modernization. This economic development has led to a huge demand for energy, most of which is derived from ...fossil fuel. However, the limited reserve of fossil fuel has led many researchers to look for alternative fuels which can be produced from renewable feedstock. Increasing fossil fuel prices have prompted the global oil industry to look at biodiesel, which is from renewable energy sources. Biodiesel is produced from animal fats and vegetable oils and has become more attractive because it is more environmentally friendly and is obtained from renewable sources. Glycerol is the main by-product of biodiesel production; about 10% of the weight of biodiesel is generated in glycerol. The large amount of glycerol generated may become an environmental problem, since it cannot be disposed of in the environment. In this paper, an attempt has been made to review the different approaches and techniques used to produce glycerol (hydrolysis, transesterification, refining crude glycerol). The world biodiesel/glycerol production and consumption market, the current world glycerin and glycerol prices as well as the news trends for the use of glycerol mainly in Brazil market are analyzed. The technological production and physicochemical properties of glycerol are described, as is the characterization of crude glycerol obtained from different seed oil feedstock. Finally, a simple way to use glycerol in large amounts is combustion, which is an advantageous method as it does not require any purification. However, the combustion process of crude glycerol is not easy and there are technological difficulties. The news and mainly research about the combustion of glycerol was also addressed in this review.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•ASPEN® HYSYS software, off-design cycle simulations were done to evaluate Organic Rankine Cycle performance;•Economic calculation, CEPCI based, evaluated the feasibility of plant implementation;•A ...technical and economic analysis for an Organic Rankine Cycle was performed.
The exhaust gases of an ICE leave the equipment still with enough temperature to generate more electric power if a proper system is used for that purpose. Therefore, due to this scenario, in this work a study of an ORC system to recovery energy from the flow gases of a stationary diesel engine. The analyses are in three parts: (1) parametric analysis of an ORC system in on-design to determine the cycle's optimal operating point; (2) parametric analysis in off-design condition, to verify the behavior of power production and cycle efficiency when the heat source's flow and temperature are varied; (3) An economic analysis, a CEPCI based model was used. The system design was determined for a working fluid flow rate of 0.09 kg/s, evaporation and condensation pressure of 3,870 kPa and 25 kPa, respectively, and with exhaust gas at 420 °C and 0.1697 kg/s. For the off-design simulations, the evaporation pressure, the working fluid flow and the heat source inlet conditions were varied. A minimum, average, and maximum net power production of 8.56 kW, 15.59 kW, and 26.29 kW, respectively, was verified, while in the design condition it was 14.72 kW, there was also an average increase in exergy of 9.35%. The initial investment for the system's implementation is US$ 23,257.02 and the financial return and rate of return reach an average of 1.5 years and 90%, respectively. The study shows that the system increases the power plant's thermal efficiency and decreases fuel consumption as well as the emission of pollutant gases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Dual-fuel led to better combustion phasing and lower CO and HC emissions.•Internal exhaust gas recirculation reduced pumping and heat transfer losses.•Increased efficiency with dual-fuel and ...internal exhaust gas recirculation.•NOx reductions of up to 70% were achieved.
This manuscript presents a deep analysis of natural gas-hydrous ethanol dual-fuel combustion in a spark ignition engine with a modified compression ratio and an advanced intake valve opening strategy to promote internal exhaust gas recirculation (iEGR). Both fuels were port-fuel injected and two different liquid fuel replacements by compressed natural gas (CNG) were tested (18 and 45% by energy). Combustion, performance and pollutant emissions were investigated under stoichiometric air-fuel conditions at 4 bar of net indicated mean effective pressure (IMEP) and 1800 rpm. Results show that dual-fuel mode improves fuel conversion efficiency when compared to CNG-only operation, due to lower carbon monoxide (CO) and unburnt hydrocarbons (HCs) emissions as well as to a better combustion phasing. The use of iEGR, despite deteriorating the combustion process as expected (ignition delay, combustion duration and combustion stability), improves efficiency because of a decrease in pumping losses and wall heat transfer, as well as pollutant emissions reduction. Nitrogen oxide (NOx) emissions increase with dual-fuel operation. However, the influence of iEGR was found to be more significant under dual-fuel mode than under single-fuel operation, with NOx reductions of up to 70% and fuel conversion efficiency improvements of around 2.5%.
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GEOZS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
•Direct injection stratified lean burn combustion using hydrous ethanol as fuel.•A single cylinder optical research engine was instrumented and used in this research.•Significant reduction of ...engine-out emissions and fuel consumption was achieved due to the use of lean mixtures.•Combustion analysis considering cyclic variability and combustion duration related to engine fuel conversion efficiency.•Important results and technology for the Latin America market application.
Fulfilling emission restrictions is the most challenging task considering future engine development. Stratified lean burn combustion mode associated with the use of biofuels has been widely studied to overcome current and future environmental regulation and global weather concerns. Power modulation by means of a throttle valve increases the pumping mean effective pressure with a corresponding penalty in engine fuel consumption at part load. De-throttling by means of direct injection (DI) is an attractive way of improving fuel economy and exhaust emissions at low and part load operation in spark-ignition (SI) engines. In this research, a study has been made of the investigations concerning stratified lean burn combustion in a wall-air guided type SI single cylinder optical research engine (SCORE) using Brazilian hydrous ethanol (E100) as fuel. Experiments were conducted at a constant load of 3 bar of net indicated mean effective pressure (NIMEP), for a wide range of injection, ignition and mixture formation parameters. Engine fuel conversion efficiency, combustion characteristics and emissions were evaluated for each excess air ratio (λ). Optical visualization illustrated the spray behavior and flame propagation. Specific fuel consumption and engine fuel conversion efficiency achieved an improvement of 8.1% and 2.6%, respectively, for λ = 1.4. Engine-out specific emissions were reduced by 66% for nitrogen oxides (NOx) and by 20% for total hydrocarbon (THC) and carbon dioxide (CO). A detailed combustion analysis based on in-cylinder pressure measurement was carried out and provided useful data for ethanol direct injection engine development.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•A technical and economic analysis for an Organic Rankine Cycle power plant was performed.•ASPENtech® HYSYS software, cycle simulations were done to evaluate Organic Rankine Cycle ...performance.•Economic calculation evaluated the feasibility of plant implementation on wet and dry areas.
Due to its low complexity, the Organic Rankine Cycle can be considered as one of the best options for waste heat recovery at low (at most 230°C) and average (230–650°C) temperatures. A technical and economic study has been conducted in this work in order to increase the efficiency of electricity production, and thus reduce fuel consumption and polluting gas emission from Internal Combustion Engines. For such a purpose, two Organic Rankine Cycle sets were suggested. The first one is facing deployment in water shortage areas (Organic Rankine Cycle using a cooling tower for the condensing system) and another one with the water supply condenser being made by the urban water net. Both simulated systems were able to increase electricity production by almost 20% when toluene was the working fluid. The economic analysis was based on the Engineering Chemical Cost Plant Index model which showed that the financial return from the implementation of the Organic Rankine Cycle system can occur in six years. Thus, it is noted that the Organic Rankine Cycle system can be installed in areas where there is no water abundance and without much yield loss. Despite being an appropriate technological solution to recover the waste heat present in Internal Combustion Engines exhaust gas, it still lacks in governmental incentives for a wide application of the system.
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GEOZS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
•Analysis of low-grade waste heat source recovery on a Brazilian offshore platform.•Multiobjective optimization analysis of ORC application with different fluids.•ORC increased the energy and ...exergetic efficiency of the platform processes.•Net power generation of 2063 kW providing a 23.6% increase in exergy efficiency.
This paper presents an analysis of the application of an Organic Rankine cycle (ORC) for power generation of a Brazilian FPSO (Floating Product Storage Offload). The peculiarity of this analysis is the investigation of power generation using low-temperature waste heat sources. Low-grade sources represent a significant amount of heat rejected on the platform. The primary production in the platform processes was evaluated using ASPEN-HYSYS® software v.8.6. The main sources of low-temperature residual heat were preliminarily identified, and the highest potential for energy recovery was: the heat rejected in the intercoolers and aftercoolers of the compression processes in the Main Compression Unit and the CO2 Compression Unit. For the development of this study, a computational tool was elaborated in MATLAB® to evaluate the thermodynamic performance and to predict the design of the heat exchanger of the ORC. A multi-objective optimization was conducted to verify the ORC application at the established sources. The higher net power was obtained at Main Compression Unit heat recovery, operating with R245CB2 as working fluid. This application allows to generate up to 2063 kW with a heat transfer area of 2997 m2, providing a 23.6% increase in exergy efficiency of the system. The results of this study suggest that the application of ORC cycles on FPSO platforms for heat recovery from low-temperature sources allows an essential increase in the energy and exergetic efficiency of the production processes of the platform. Although the ORC doesn’t give a substantial increase in the supply of electricity, they contribute to less gas consumption in gas turbines. In this way, contributing to a significant reduction of GHG emissions.
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GEOZS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
•Mathematical model developed for pre-chamber torch ignition system design.•Experimental characterization with hydrous ethanol (PFI) and lean burn combustion.•Improved turbulent kinetic energy is ...generated by the pre-chamber.•Faster combustion process characterized by combustion analysis and visualization.•52% reduction of NOx emissions and improvements in ethanol conversion efficiency.
Energy is the key to wellbeing and sustainability of modern civilization and its demand continues to increase. With the end of oil availability perspectives and the world energy crisis, technological solutions are needed from the scientific community to promote the reduction of fossil fuel consumption, the maximization of fuel conversion efficiency and the reduction of emission levels in internal combustion engines. Aiming at reaching these needs, the use of a pre-chamber ignition system in spark-ignition (SI) engines is a potential alternative enabling such engines to operate with lean mixtures and with a wide variety of fuels. In this study, a methodology was developed to design and characterize experimentally a homogeneous charge pre-chamber torch ignition system fuelled with hydrous ethanol (with 6–7% in mass of water content) and using lean burn mixtures (excess air ratio (λ) > 1.0). The methodology, which has not been reported previously in other works, consisted of a one-dimensional mathematical model, that allowed for the definition of pre-chamber geometrical parameters. The device was manufactured and adapted to an SI engine, requiring no additional work to the cylinder head, as the pre-chamber was mounted in the original spark-plug screw thread. The prototype was experimentally characterized on an active dynamometer, and performance, combustion, emission and combustion visualization were studied. The pre-chamber ignition engine expanded the flammability limit in comparison with the baseline engine. For λ = 1.4, engine fuel conversion efficiency was increased by 5.4%, specific fuel consumption decreased by 22% and nitrogen oxides (NOx) emissions reduced by 52%, but total hydrocarbons (THC) emissions increased. Improvements achieved were due to the faster burn rates characterized by the reduced MBF 0–10%, combustion duration and combustion instability, and also the increased thermodynamic efficiency and the lower combustion temperatures achieved with lean burn technology. From the conclusions obtained in this research, the homogeneous pre-chamber torch ignition system developed for hydrous ethanol has potential for application and marketability integration, as an alternative technology able to help meet energy demands in a sustainable manner.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This work reports the experimental study of a single-cylinder compression ignition engine fueled with a renewable diesel from sugarcane called farnesane. The engine is representative of current ...small-scale power generation in very isolated rural areas existing in Brazil. A complete experimental assessment was made on engine combustion, performance, and pollutant emissions at 1800 rpm under different loads (from 4 to 7 bar IMEP). Results showed reduced values for the ignition delay, in-cylinder peak pressure and mean temperature when using farnesane compared to conventional diesel fuel, as well as lower heat release rate peaks at the premixed combustion phase and shorter diffusion combustion duration. Physicochemical properties differences, such as cetane number, H/C ratio and the biofuel paraffinic structure led to interesting emission behavior. Farnesane reduced NOx emissions by up to 34% (and further 48.6% using EGR), and particulate matter by up to 92%. Despite the higher in-cylinder peak pressure and greater fuel conversion efficiency for diesel fuel at the highest load, the biofuel exhibited gains of up to 3.3% in combustion efficiency and 5.9% in fuel conversion efficiency at intermediate and lower loads. Such improvements are closely related to the HC and CO levels depletion and the absence of aromatic compounds.
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•Renewable diesel from sugarcane (Farnesane) was tested in a single-cylinder engine.•Engine application is representative of small-scale power generation in rural areas.•Physicochemical properties of Farnesane improved combustion behavior.•Farnesane reduced gaseous and particulate matter emissions compared to diesel.•Fuel conversion efficiency increased up to 5.9% when using Farnesane.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of this work is to develop stoichiometric equilibrium models that permit the study of parameters effect in the gasification process of a particular feedstock. In total four models were tested ...in order to determine the syngas composition. One of these four models, called M2, was based on the theoretical equilibrium constants modified by two correction factors determined using published experimental data. The other two models, M3 and M4 were based in correlations, while model M4 was based in correlations to determine the equilibrium constants, model M3 was based in correlations that relate the H2, CO and CO2 content on the synthesis gas. Model M2 proved to be the more accurate and versatile among these four models, and also showed better results than some previously published models. Also a case study for the gasification of a blend of hardwood chips and glycerol at 80% and 20% respectively, was performed considering equivalence ratios form 0.3 to 0.5, moisture contents from 0%–20% and oxygen percentages in the gasification agent of 100%, 60% and 21%.
•Shows in detail the equilibrium modeling process of biomass gasification.•Four models were developed and tested; the more accurate and versatile was selected.•A case study on gasification of a hardwood-glycerol blend is presented.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
An analysis of Brazilian public costs indicates that, although a significant part of its financial resources is destined for electricity consumption, only a small portion of the distributed ...generation belongs to public institutions. A technical and economic analysis of a PV power plant in the Brazilian public sector was proposed and various scenarios were evaluated, indicating that a change in the Brazilian tariff policy could be an alternative for boosting PV generation in the public sector. Risk analysis demonstrated that the minimum acceptable rate of return is the variable that most affects the system’s viability. In addition, a Monte Carlo Simulation (MCS) showed that the proposed PV system has a viability probability higher than 92%. A statistical analysis indicated that the system has a probability of at least 80% for supplying more than 25% of the building’s peak demand for all seasons. Finally, such systems have also been found to represent an alternative for improving the electricity grid’s stability, while supplying part of the building’s energy demand.
•A PV power plant was projected for a building of a Brazilian public university.•The variable that most affected the system viability is the MARR.•Changes in the tariff policy could boost the PV generation in the public sector.•There is an 87% chance of the maximum inverter power being reduced in at least 25%.•Similar systems can reduce the summer peak consumption in public buildings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
