Search

The present study is focused on the combustion behavior, performance and emissions of a modified diesel engine working on dual fuel mode with hydrogen as a gaseous fuel by the inclusion of tri-ethylene glycol mono methyl ether and alumina nanoparticles as fuel additives. The inclusion of tri-ethylene glycol mono methyl ether, alumina and hydrogen separately and simultaneously improved the net heat release with reduced cylinder pressure at high loads as compared with neat diesel. The brake thermal efficiency increased by 22.5% and 11.6% by the inclusion of tri-ethylene glycol mono methyl ether and hydrogen respectively at 50% load, when combined together, it was improved remarkably by 28.15%. The addition of alumina was responsible for a slight reduction in NO x formation at all loads, while it was incremented by hydrogen enrichment at the highest load as compared to pure diesel. The CO formation was incremented by the addition of alumina, while the CO 2 and HC formations were reduced up to 50% load, increased at 70% load. The CO, CO 2 , HC and smoke opacity were reduced with TGME and hydrogen enrichment, while the NO x formation was reduced up to 50% load, then increased at the higher load. • The H 2 enrichment incremented NHR by 21.7% at 356°CA. • A minimum ID of 11°CA was observed in case of D + TGME @5%. • BTE increased by 28.15% at a load of 50% for D + TGME @5% +H 2@35%. • For D + TGME @5% , combustion efficiency improved by 10.4%. • The HC formation was reduced by 21.8% for D + TGME @5% at 50% load. [ABSTRACT FROM AUTHOR]

In the present review, using an integrated approach based on the experimental and theoretical study of the processes of thermal decomposition and combustion of practically important polymers, such as polymethyl methacrylate, polyethylene, and glass-fiber-reinforced epoxy resin, the features of the mechanism for reducing the combustibility of these materials with phosphorus-containing flame-retardants (FR), as well as graphene, are identified. A set of original experimental methods was developed and applied that make it possible to study the kinetics of thermal decomposition and the thermal and chemical structure of the flames of the studied materials, including those with FR additives, as well as to measure the flame propagation velocity, the mass burning rate, and the heat fluxes from the flame on the surface of a material. Numerical models were developed and tested to describe the key parameters of the flames of the studied polymeric materials. An analysis of the experimental and numerical simulation data presented showed that the main effect of phosphorus-containing fire-retardants on reducing the combustibility of these materials is associated with the inhibition of combustion processes in the gas phase, and the effect of adding graphene manifests itself in both gas and condensed phases. [ABSTRACT FROM AUTHOR]

Extensive research is being conducted to create and use a wide range of alternative fuels to accommodate the world's growing energy needs. The objective of this experimental investigation was to analyze the effects of Karanja biodiesel blends on the performance, combustion, and emission characteristics of a compression ignition (CI) engine vis-a-vis neat diesel. Important physical parameters of Karanja oil were examined experimentally after transesterification and determined to be within acceptable limits. BTE of Karanja biodiesel blends was about 3-8% lower than diesel. For Karanja biodiesel blends, BSFC was about 2-9% higher than diesel but exhaust gas temperature and volumetric efficiency were lower. Emissions characteristics such as nitrogen oxides, hydrocarbons, and carbon monoxide were also analyzed for various tested fuels. Karanja biodiesel blends resulted in lesser CO and HC formation. Nonetheless, NOx emissions were around 10% greater than diesel. Peak cylinder pressure, heat release rate, and maximum rate of pressure rise versus crank angle were among the combustion characteristics parameters considered in this study. Combustion analysis revealed that for Karanja biodiesel blends heat release rate and peak cylinder pressure were lower than for neat diesel. Findings indicate that Karanja biodiesel can be considered a viable diesel engine fuel. [ABSTRACT FROM AUTHOR]

Abstract: Triticale, a hybrid between wheat and rye, has gained the attention of researchers as a feasible future energy crop for Canada. The study focuses on development of data intensive techno-economic model for assessment of triticale straw-based electricity generation, its optimum size and the GHG abatement potential through substitution of coal-based power on a commercial scale. Each of the unit operations required for utilization of triticale straw to power generation are developed and assessed. Direct combustion is the power generation technology considered due to its reliability and large-scale commercial availability. The cost of triticale straw-based power production via direct combustion is in the range of $76.33±4.76/MWh, at a boiler unit size of 300MW. The estimated carbon credit required for triticale straw based power plant to be competitive with coal based power is $16.4/MgCO2e. When the unit size of plant is unlimited, the optimum size of power plant and the cost of power are 595MW and $75.02/MWh, respectively. [Copyright &y& Elsevier]

Biomass is nearly carbon neutral and can be used for the production of various liquid fuels and chemicals. Decisions on biomass utilization should be based on the most economical and mature route. This study analyzes mountain pine beetle (MPB) killed wood as the feedstock for production of bio-ethanol and bio-oil and compares it with the direct combustion route to produce electricity. The MPB infestation of British Columbia’s (BC), a western province of Canada, forest has reached an epidemic proportion and is spread over an area of 10 millionha. According to the current estimates of BC‘s Ministry of Forests and Range, about 1 billion m3 of trees would be killed by MPB by 2013. This infestation would result in large scale loss of jobs and the standing dead trees are a fire hazard and if left unharvested will decay and release carbon back to the atmosphere. The cost of bio-ethanol production from a 2100dry tonne/day plant using the infested wood for two locations (one remote and other near the industry) in BC is in the range of C$0.37–C$0.40/l (C$1.40–C$1.51/gallon). Similarly, cost of bio-oil production from a 220dry tonne/day plant using the infested wood for same two locations in BC is in the range of C$0.27–C$0.29/l (C$1.02–C$1.09/gallon). The cost of producing electricity using this bio-oil is above C$100/MWh which is higher than the current power price in BC. This cost is also higher than the cost of production of electricity by direct combustion of infested wood in a boiler (C$68–C$74/MWh). [Copyright &y& Elsevier]

Growing concern over climate change has created pressure on the oil and gas industry to reduce their greenhouse gas emissions (GHG). There have been multiple well-to-tank + combustion (WTT + C) studies that have examined various crude oils in an attempt to determine their GHG emission intensities. The majority of these studies published deterministic point estimates with a limited sensitivity analysis. Due to the variation in results between studies and the lack of uncertainty analysis the usefulness of these studies to policy makers and industry representatives is limited. The goal of this study is to expand on the previous literature by identifying a range of WTT + C emissions for crude oils from Saudi Arabia, Venezuela, and Iran. First, the previously published FUN damental E N gineering Principl E s-based Mode L for Estimation of G reen H ouse G ases in C onventional C rude O ils (FUNNEL-GHG-CCO) was used to perform a WTT + C analysis of the crudes GHG emissions. Then a Monte Carlo simulation was carried out using existing literature to define input distributions for the key inputs. The resulting gasoline WTT + C GHG emission ranges are 113.6–138.5 (Venezuela High Steam), 101.6–109.9 (Venezuela Low Steam), 101.1–109.2 (Sirri, Iran), and 95.3–99.9 gCO 2 eq/MJ (Saudi Arabia). This result indicates that even when uncertainty is taken into account the Venezuelan high steam crude clearly has higher emissions than the Saudi Arabia crude. The results of this study will give policy makers and industry representatives a better understanding of how the WTT + C GHG emissions vary between various crude oils. [ABSTRACT FROM AUTHOR]

Nano-crystalline Co 3 O 4 is synthesized using solution combustion method. Characterization is done using XRD, TEM and BET surface area analysis. XRD shows pure nano-crystalline phase of Co 3 O 4 . Crystallinity of as prepared material improves by calcining the compound at 900 °C for 10 h while no effect is seen at 600 °C. TEM studies show that particles of around 50 nm size are formed at 400 °C. At 600 °C a well-defined hexagonal morphology could be seen both by TEM and SEM and the particle size is around 70 nm. However, TEM of the sample at 900 °C shows big agglomerates of cobalt oxide and no specific geometry could be obtained. Estimated BET surface area for the sample calcined at 600 °C is 10 m 2 /g. Detailed electrochemical studies are carried out in neutral and basic electrolytes where Ag/AgCl is used as the reference electrode. It is found that Co 3 O 4 is active for oxygen evolution reaction in basic medium as well as in neutral medium. KOH is used as the basic medium while KNO 3 , K 2 SO 4 and phosphate buffer is used for neutral medium. However, it is not active for hydrogen evolution reaction in any of the medium even at − 1.0 V. This is confirmed by gas analysis of the output gas in the cell by using a mass spectrometer. When compared with the buffer medium, it is observed that local pH changes in KNO 3 and K 2 SO 4 medium are possibly affecting the oxygen evolution reaction. [ABSTRACT FROM AUTHOR]

A life cycle assessment (LCA) is an extremely useful tool to assess the greenhouse gas (GHG) emissions associated with all the stages of a crude oil’s life from well-to-wheel (WTW). All of the WTW life cycle stages of crude oil consume energy and produce significant amounts of GHG emissions. The present study attempts to quantify the WTW life cycle GHG emissions for transportation fuels derived from five North American conventional crudes through the development of an LCA model called FUNNEL-GHG-CCO ( FUN damental E n gineering Principl E s-based Mode L for Estimation of G reen H ouse G ases in C onventional C rude O ils). This model estimates GHG emissions from all the life cycle stages from recovery of crude to the combustion of transportation fuels in vehicle engines. The contribution of recovery emissions in the total WTW GHG emissions ranges from 3.12% for Mars crude to 24.25% for California’s Kern County heavy oil. The transportation of crude oil and refined fuel contributes only 0.44–1.73% of the total WTW life cycle GHG emissions, depending on the transportation methods and total distance transported. The GHG emissions for refining were calculated from the amount of energy use in the refining of crude oil to produce transportation fuels. All the upstream GHG emissions were allocated to gasoline, diesel, and jet fuel. Refining GHG emissions vary from 13.66–18.70 g-CO 2 eq/MJ-gasoline, 9.71–15.33 g-CO 2 eq/MJ-diesel, and 6.38–9.92 g-CO 2 eq/MJ-jet fuel derived from Alaska North Slope and California’s Kern County heavy oil, respectively. The total WTW life cycle GHG emissions range from 97.55 g-CO 2 eq/MJ-gasoline derived from Mars crude to 127.74 g-CO 2 eq/MJ-gasoline derived from California’s Kern County heavy oil. [ABSTRACT FROM AUTHOR]

Agricultural residues, although widely available, are an unused source of energy in Bolivia. Although the government of Bolivia plans to increase the share of renewables in the power portfolio, none of the proposed projects includes agricultural residues as a source of electricity. The present study investigated the techno-economics of a biomass-based electricity generation facility, including the optimum facility size and the levelized cost of electricity from agricultural residues in Bolivia. The biomass feedstocks are the residues from harvesting sugarcane, soybean, corn, rice, sorghum, and sunflower. A novel framework was developed to geographically locate biomass collection points (BCPs), sites for collecting/storing biomass on roadsides using a model developed using GIS. The cost components are the costs of harvesting biomass from fields, baling, transportation to BCPs, storage, nutrient replacement, the premium paid to the farmer, and capital cost for the plant. The transportation costs were estimated using a detailed GIS study through the analysis of the actual road network, and the transportation costs were optimized. Regression models were developed to assess the capital costs of the combustion plants. The conversion technologies considered for Bolivia were grate-firing and fluidized bed combustion. A novel integrated framework, named EN ergy from BIO mass T echno E conomic M odel (ENBIOTEM), was developed. Using this model, we estimated the energy cost to be 71.6 $/MWh for an optimal plant capacity of 300 MW. The main barrier against promoting renewables in Bolivia is the fossil fuel subsidy. Although biomass is currently not competitive with fossil fuels in Bolivia, the results provide information to decision makers for future planning. • A data-intensive techno-economic model was developed for estimation of biopower in Bolivia. • GIS was used to estimate the actual transportation cost using road network in Bolivia. • Regression model-based capital cost was integrated with GIS model to estimate biopower cost. • The biopower cost could be an option for providing in long term when natural gas runs out in Bolivia. [ABSTRACT FROM AUTHOR]

The burning behavior of polyoxymethylene in the counterflow of oxidizing air has been studied experimentally and numerically. Measurements have been performed using a specially designed burner. The temperature profiles were measured in gas phases by a microthermocouple technique. The burning surface temperature and the mass burning rates of solid fuel were determined. The chemical structure of counterflow flame was investigated using the mass spectrometric sampling by microprobe. The composition of the gas sample was analyzed on-line with a mass spectrometric complex (Hiden HPR 60), based on a quadrupole mass spectrometer. The species CH 2 O, CO, CO 2 , H 2 O, O 2 , N 2 were identified and their concentration profiles were measured. The composition of products and kinetic parameters of POM thermal degradation have been determined by mass spectrometry and thermogravimetric analysis. Quasi one-dimensionality of considered diffusion flame has been established experimentally, which allows analysis of flame parameters in relation to the only coordinate normal to the solid fuel's burning surface and substantially simplifies the theoretical description. Predictions have been performed by a coupled model describing feedback heat and mass transfer between gas-phase flame and polymeric solid fuel. A two-dimensional elliptic equation in axisymmetric formulation has been employed to simulate heat transfer in solid fuel, and a set of one-dimensional hyperbolic equations has been used to determine the solid-to-gas conversion degree of the pyrolysis reaction. Gas-phase formulation is presented by one-dimensional conservation equations for multi-component flow with a detailed kinetic mechanism of combustion. Numerical results showed good agreement with the measurements for temperature and species concentration profiles, as well as for the mass burning rate and the surface temperature of solid fuel. [ABSTRACT FROM AUTHOR]

Carbonation of sodium aerosols is the most important aspects to be considered for the evaluation of chemical hazards as a part of fast reactor safety studies. The sodium oxide, immediately formed as the combustion product due to sodium fire, undergoes chemical changes to NaOH, Na 2 CO 3 and NaHCO 3 upon reactions with moisture and CO 2 prevailed in the atmosphere. Of which, hydroxide aerosols are highly corrosive and harmful, and it has stringent concentration limit for human exposure. Hence, in order to assess the condition for human intervention in the event of sodium fire, chemical composition of aerosols resulting from controlled sodium fires in a closed Aerosol Test Facility was investigated. The real time chemical species of aerosols generated from sodium fire and the effect of relative humidity (RH) and carbon dioxide concentration in air on carbonation have been studied. The experiments were carried out with the initial mass concentration of ∼4 g m −3 , RH between 20% and 90% and the CO 2 concentration in surrounding environment at 390 and 280 ppm. It is observed from the experimental study that aerosols are enriched with NaOH (0.8 mol fraction) in the beginning stage (samples collected during first few minutes after sodium fire) when surrounding atmosphere contains any of the following compositions – (i) ∼90% RH and 390 ppm CO 2 , (ii) ∼90% RH and 280 ppm CO 2 or (iii) 50% RH and 280 ppm CO 2 whereas they are almost equally distributed between NaOH and Na 2 CO 3 in the beginning stage when the atmosphere has any of the compositions (i) 50% RH, 390 ppm CO 2 , (ii) 20% RH, 390 ppm CO 2 or (iii) 20% RH, 280 ppm CO 2 . Carbonation of aerosols is completed between 20 min and 1 h just after sodium fire depending upon the prevailing atmosphere. The present study shows that highly humid condition promotes carbonation process. Faster the carbonation process the lesser would be the chemical hazard. [ABSTRACT FROM AUTHOR]