Showing papers in "Journal of The Energy Institute in 2013"
TL;DR: In this article, a high temperature fast pyrolysis of wood, rice husk and forestry wood residue was carried out in a laboratory scale fixed bed reactor and the results showed that the increase in temperature increased overall gas yield and also increased hy...
Abstract: High temperature fast pyrolysis of wood, rice husk and forestry wood residue was carried out in a laboratory scale fixed bed reactor. The results were compared with pyrolysis of the biomass samples in a different reactor under slow pyrolysis conditions. There was a marked difference in product yield depending on heating rate, for example the gas yield from slow pyrolysis was 24·7 wt-% for wood, 24·06 wt-% for rice husks and 24·01 wt-% for forestry residue; however, for fast pyrolysis, the gas yields were 78·63, 66·61 and 73·91 wt-% respectively. There were correspondingly significantly lower yields of oil and char from fast pyrolysis, whereas for slow pyrolysis, oil and char yields were higher. The composition of the product gases was also influenced by the heating rate. In additional experiments, the influence of pyrolysis temperature was investigated under fast pyrolysis conditions from 750 to 1050°C. It was found that the increase in temperature increased overall gas yield and also increased hy...
35 citations
TL;DR: In this article, a model of a quantum harmonic oscillator Carnot refrigerator with heat resistance, internal irreversibility and heat leakage is established, based on the quantum master equation and semigroup approach, equations of some important performance parameters, such as cooling load, coefficient of performance (COP), exergy output rate, entropy generation rate and ecological function are derived.
Abstract: A model of a quantum harmonic oscillator Carnot refrigerator with heat resistance, internal irreversibility and heat leakage is established in this paper. Based on the quantum master equation and semigroup approach, equations of some important performance parameters, such as cooling load, coefficient of performance (COP), exergy output rate, entropy generation rate and ecological function (a criterion E = A/τ−T0σ representing the optimal compromise between exergy output rate A/τ and exergy loss rate T0σ), for the irreversible quantum Carnot refrigerator are derived. The optimal ecological performance of the refrigerator at high temperature limit is analysed using numerical examples. The effects of internal irreversibility and heat leakage on the optimal ecological performance are discussed. Performance comparisons of the quantum refrigerator under maximum ecological function, maximum COP and maximum cooling load conditions are also performed. Some special cases, i.e. endoreversible, frictionless a...
26 citations
TL;DR: In this article, a combined cooling, heating and power (CCHP) plant model composed of an irreversible closed Brayton cycle and an endoreversible four-heat-reservoir absorption refrigeration cycle is established by using finite time thermodynamics.
Abstract: A combined cooling, heating and power (CCHP) plant model composed of an irreversible closed Brayton cycle and an endoreversible four-heat-reservoir absorption refrigeration cycle is established by using finite time thermodynamics. Equations of exergy output rate and exergy efficiency of the CCHP plant are derived. Numerical examples are provided by using Powell arithmetic, and optimal heat conductance distributions among hot-, cold-, thermal consumer-, generator-, absorber-, condenser- and evaporator-side heat exchangers and compressor optimal pressure ratios are obtained by taking exergy output rate and exergy efficiency as optimisation objectives respectively. The effects of compressor and gas turbine efficiencies on the optimal exergy output rate and exergy efficiency performances are discussed. The maximum exergy output rate and exergy efficiency performances are compared with each other quantitatively. Optimal design region is obtained with considerations of exergy output rate and exergy effi...
20 citations
TL;DR: Carbon reinforced composite plastic (CRCP) waste has been pyrolysed under nitrogen atmosphere in a batch stainless steel autoclave between temperatures of 350 and 500°C and reaction times of up to 60 min this paper.
Abstract: Carbon reinforced composite plastic (CRCP) waste has been pyrolysed under nitrogen atmosphere in a batch stainless steel autoclave between temperatures of 350 and 500°C and reaction times of up to 60 min. The reaction products were dominated by solid residue (72–77 wt-%), gas (2–4 wt-%) and liquid (22–25 wt-%). The solid residue consisted mainly of carbon fibre, giving up to 98 wt-% recovery. However, the mechanical properties of the recovered fibres were lower when compared with a sample of virgin carbon fibre. The gas products contained mainly carbon dioxide and some hydrocarbon gases. The proportion of the combustible gases gave calorific values of up to 35 MJ m−3. The liquid products consisted of 15–20 wt-% water, possibly from the degradation of the amide/ester linkages in the resin, and the rest was dark brownish oils, soluble in dichloromethane. The thermal gravimetric/differential thermogravimetric analysis of the CRCP waste indicated that the primary resin present could be based on polybe...
19 citations
TL;DR: In this article, low grade biomass fibre produced as a byproduct from the flax industry was manufactured into a nonwoven fabric and then pyrolysed in a fixed bed reactor to produce biochar.
Abstract: Low grade biomass fibre produced as a byproduct from the flax industry was manufactured into a non-woven fabric. This material was then pyrolysed in a fixed bed reactor to produce biochar. The resulting biochars were characterised using a variety of techniques including gas adsorption, scanning electron microscopy, pychnometry and elemental and proximate analyses. The fibrous morphology of the precursor was retained during pyrolysis. The temperature of pyrolysis had a significant influence on the biochar properties, with higher temperatures causing an increase in surface area and density along with a decrease in volatile/disorganised carbon. All of the biochars were microporous, with the majority in the ultramicropore size range. Activated diffusion effects were observed during nitrogen adsorption measurements at 77 K. The experimental data show that the flax biochars exhibit properties typical of biochars produced from other lignocellulosic precursors.
18 citations
TL;DR: In this paper, the optimum concentration of oxygen in the torrefier that can be tolerated without greatly compromising the product quality is examined, and the results of torrefaction of relatively large pieces of poplar wood were conducted at different oxygen concentration as well as in inert atmosphere while observing its effect on the temperature profile in the biomass interior, mass yield, energy yield and energy density.
Abstract: Torrefaction, though defined as a low temperature (200–300°C) decomposition of biomass in an oxygen free atmosphere, it is hard to obtain such environment in a commercial unit unless one uses expensive means of nitrogen flushing or indirect heating. Oxygen leakage that adversely affects the product quality is unavoidable in commercial directly heated torrefier. Present work attempts to examine the optimum concentration of oxygen in the torrefier that can be tolerated without greatly compromising the product quality. In this work, torrefaction of relatively large pieces (25·4 and 19 mm diameter) of poplar wood was conducted at different oxygen concentration as well as in inert atmosphere while observing its effect on the temperature profile in the biomass interior, mass yield, energy yield and energy density. Results obtained are in agreement with those obtained in previous work on fine biomass particles that mass yield and energy yield decreases with oxygen presence in the torrefier. It, however, ...
12 citations
TL;DR: In this article, the authors introduced the ecological criterion into the optimal configuation problem of an irreversible light driven engine with a working fluid composed of the bimolecular reacting system, in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law.
Abstract: The ecological criterion is introduced into the optimal configuation problem of an irreversible light driven engine with a working fluid composed of the bimolecular reacting system , in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law []. Piston trajectory for maximum ecological performance is determined with rate dependent loss mechanisms of friction and heat leakage. Numerical examples of optimal configurations for maximum ecological performance are provided. The obtained results are not only compared with those for maximum work output and minimum entropy generation with linear phenomenological heat transfer law but also compared with those for maximum ecological performance with Newton’s heat transfer law. The results indicate that taking maximum ecological criterion as the objective makes larger improvement of the reduction in the entropy generation with the cost of a little decrease in the work output.
11 citations
TL;DR: In this article, a new method named "water steam injection" is introduced as a measure to reduce NOx emissions, where required energy for producing water steam has been obtained from exhaust energy via the heat exchanger which was mounted to exhaust line of the engine.
Abstract: In the present study, a new method named ‘water steam injection’ is introduced as a measure to reduce NOx emissions. Required energy for producing water steam has been obtained from exhaust energy via the heat exchanger which was mounted to exhaust line of the engine. Main advantages of this method over the fumigation and emulsified fuel techniques, corrosive side effects of water on metallic surface have been eliminated by changing the phase of compressed hot water at 300 kPa and 133°C to superheated vapour conditions at 101·325 kPa and inlet temperature. Optimum steam rate was obtained as 20% from the performance and the exhaust emissions points of view. The test results obtained from the partial load conditions are given comparatively. In a wide speeds and engine loads intervals, while the effective brake power and the efficiency increased, specific fuel consumption and NOx emission decreased.
9 citations
TL;DR: In this article, a study of the heat exchanges in the early stages of the biomass pyrolysis is performed using a thermogravimetry/differential scanning calorimetry device.
Abstract: A study of the heat exchanges in the early stages of the biomass pyrolysis is performed in this work. A thermogravimetry/differential scanning calorimetry device was employed to perform the tests. First, the specific heat capacity of several biomasses is calculated for a determined temperature range, obtaining a fitting curve for each case. Then, using derivative thermogravimetry curves, heat exchanges during the pyrolysis of the same samples are related with the composition in the three main components of the biomass.
7 citations
TL;DR: In this paper, the pyrolysis process of xylan as a hemicellulose model compound has been simulated by molecular dynamics method, and the simulation results show that the process can mostly be divided into three stages.
Abstract: Xylan is the most relevant component in hemicellulose, and in order to understand the mechanism of thermal decomposition of hemicellulose, the pyrolysis process of xylan as a hemicellulose model compound has been simulated by molecular dynamics method. The simulation results show that the pyrolysis process of xylan can mostly be divided into three stages: low, intermediate and high temperature pyrolysis stage. The hydroxyl bonds begin to break down when temperature rises to about 400 K. The glycosidic bonds on side groups begin to break down at about 550 K, and those on main chain begin to break down at about 600 K. Thus, the whole molecule depolymerises and all kinds of fragments are formed. Based on the related experimental results in references, the possible formation pathways of major products have been analysed.
6 citations
TL;DR: Pressed sugar beet pulp with a moisture content of 71% and wood chips with moisture contents of 15 and 55% were co-firing with Thoresby coal in a 25 kW thermal capacity bubbling fluidized bed combustor over a wide range of operating conditions.
Abstract: Pressed sugar beet pulp with a moisture content of 71% and wood chips with moisture contents of 15 and 55% were cofired with Thoresby coal in a 25 kW thermal capacity bubbling fluidised bed combustor over a wide range of operating conditions. The wood chips were blended with the coal in 50/50 (wt/wt) ratio. The overall moisture content of the blends was 10·3 and 30·3%. The pulp was blended with the coal in 70/30, 60/40 and 50/50 (coal/pulp, wt/wt) ratios. The overall moisture content of the blends was 25·2, 31·8 and 38·3% respectively. Emissions of NOx for the tests are compared with those from coal only firing. The emissions of NOx are found to be lower during cofiring as compared to coal only firing due to lower nitrogen content of biomass fuels. The emissions increased with increase in bed temperature when only coal was fired but decreasde with increase in bed temperature when coal pulp blends were cofired. Moreover, the emissions increase with increase in the amount of excess air. The effect of moistu...
TL;DR: In this article, an endoreversible MG cycle model is established using the finite time thermodynamic theory with considerations of heat transfer loss and the non-linear relation between specific heat of working fluid and its temperature.
Abstract: Meletis–Georgiou (MG) vane rotor engine incorporates the exhaust gas recirculation process at the basis of Miller cycle, which produces a new cycle. An endoreversible MG cycle model is established using the finite time thermodynamic theory with considerations of heat transfer loss and the non-linear relation between specific heat of working fluid and its temperature. The analytical formulae of work output and efficiency are derived, and the cycle performance is analysed and optimised by detailed numerical examples. The effects of heat transfer loss, the non-linear relation between specific heat of working fluid and its temperature and design parameters on the cycle performance are discussed. The results obtained in this paper can provide some guidelines for the design of practical MG vane rotary engine cycle.
TL;DR: In this paper, the authors presented a fuel characterisation study using Pakistani coals with reference to gasification, and the results showed that the Chakwal coals have manageable quantity of moisture (3-6%), high vol...
Abstract: This article presents a fuel characterisation study using Pakistani coals with reference to gasification. Pakistan has reasonable quantities of coal reserves, but most of this natural resource is underutilised. The energy crisis in the country demands investigating new avenues. Gasification of coal is one of the available alternatives. A detailed analysis of indigenous coal for the feasibility of gasification to generate power is desired. Six samples from the Chakwal coal mines in Pakistan were collected and analysed for proximate, ultimate, thermogravimetric (TG) and X-ray florescent spectrometric analyses. Numerous gasification processes are being employed in the world for power generation, district heating, factory, in-house, utility, etc. Almost all types of coals can be used, but the main issues are the polluting effect on the environment, economic justification and employment of suitable technology. The results show that the Chakwal coals have manageable quantity of moisture (3–6%), high vol...
TL;DR: In this paper, the authors investigated the catalytic properties of four different coal liquefaction catalysts and found that FeS+S and CoMo/Al2O3 catalysts have the highest catalytic activity for the liquefactions of Shenhua coal and sawdust respectively, and the main synergistic interaction is reflected by the promotion of preasphaltene formation.
Abstract: Coliquefactions of a subbituminous coal and sawdust over four different coal liquefaction catalysts were studied, and the coliquefied products were characterised by elemental analysis, Fourier transform infrared spectroscopy and gel permeation chromatogram measurements. It is found that FeS+S and Co–Mo/Al2O3 catalysts have the highest catalytic activity for the liquefaction of Shenhua coal and sawdust respectively. There exists synergistic effect in the coliquefaction of Shenhua coal and sawdust, and the main synergistic interaction is reflected by the promotion of preasphaltene formation. The catalytic activities of the four catalysts in the coliquefaction are quite different from their catalytic activities in the individual liquefaction of coal and sawdust. FeS gives the lowest catalytic activity for the coal liquefaction among the four catalysts but has the highest promotion to the synergistic effect in conversion in the coliquefaction of Shenhua coal and sawdust. diminishes this synergistic ef...
TL;DR: Mn0·4/Co0·1Ce0-45Zr0·45OX was prepared by introducing Co into Mn/Ce-ZrOX and was used for low temperature selective catalytic reduction (SCR) of NO with NH3 at different reaction conditions as mentioned in this paper.
Abstract: Mn0·4/Co0·1Ce0·45Zr0·45OX was prepared by introducing Co into Mn/Ce–ZrOX and was used for low temperature selective catalytic reduction (SCR) of NO with NH3 at different reaction conditions. X-ray diffraction, temperature programmed desorption and temperature programmed reduction were performed to character the physicochemical property of the catalyst and supports. Experimental results showed that the introduction of Co increased the surface acidity and improved the redox properties of the catalysts. Mn0·4/Co0·1Ce0·45Zr0·45OX produced a good activity at low temperature, and the NO conversion of the catalyst was >90% in the temperature range of 120–220°C. Furthermore, Mn0·4/Co0·1Ce0·45Zr0·45OX showed an excellent resistance to SO2 and H2O at different reaction conditions. The catalytic activity was stable during the treatment of SO2 and H2O, and the activity recovered to the original level after cutting off the injection of SO2 and H2O. Therefore, Mn0·4/Co0·1Ce0·45Zr0·45OX is a promising catalyst f...
TL;DR: In this paper, the effects of varying coolant hole diameter, hole pitch/diameter ratio and coolant injection angles on the transpiration cooled (full coverage film cooled) gas turbine cycle performance were investigated for a TIT of 1700 K and a cycle pressure ratio of 23.
Abstract: Gas turbine cycles are extensively used in view of their capability of offering high specific work output with high thermal efficiency compared to steam turbine cycles. Studies are being carried out worldwide to further improve the gas turbine cycle performance. Among different options for improving cycle performance, the use of high turbine inlet temperature (TIT) along with efficient means and methods of turbine blade cooling is an attractive option. Studies show that transpiration cooling technique uses the coolant more effectively than the film and convection cooling techniques.The present study investigates the effects of varying coolant hole diameter, hole pitch/diameter ratio and coolant injection angles on the transpiration cooled (full coverage film cooled) gas turbine cycle performance. The results have been taken for a TIT of 1700 K and a cycle pressure ratio of 23, as used in the advanced ‘H’ class gas turbines. It is found that the coolant requirement increases with the increasing coo...
TL;DR: In this paper, the authors investigated the ignition temperature and burnout characteristics of coal by thermal gravimetric analysis and found that coals and wastes type had significant influences on the catalytic combustion.
Abstract: Steel slag, desulphurisation slag of molten iron during steelmaking and red iron oxide in cold rolling were used as coal burning additives. The objective of this study was to investigate ignition temperature and burnout characteristics of coal by thermal gravimetric analysis. The results indicated that coals and wastes type had significant influences on the catalytic combustion. The ignition temperature and burnout time of catalytic samples were all decreased; meanwhile, the burnout index of catalytic samples were enhanced. Red iron oxide in cold rolling was the optimal coal burning additive. The study exploits a new way to use the wastes of steel industry and provides some important theoretical data and a useful basis for further applying coal with high efficiency.
TL;DR: In this article, a multistage isothermal endoreversible chemical pump system with a finite potential capacity high chemical potential mass reservoir and the linear mass transfer law was investigated, and the minimum power consumption was derived by applying Hamilton-Jacobi-Bellman optimisation theory analytically.
Abstract: A multistage isothermal endoreversible chemical pump system with a finite potential capacity high chemical potential mass reservoir and the linear mass transfer law (g∝Δμ) is investigated in this paper. For the fixed initial time and fixed initial concentration of the key component, the minimum power consumption of the multistage chemical pump system and the corresponding optimal concentration configuration of the key component in the high chemical potential reservoir are derived by applying Hamilton–Jacobi–Bellman optimisation theory analytically, and the obtained results are also compared with those obtained for the maximum power output of the multistage endoreversible chemical engine system. The results in this paper provide a new performance limit for fluid flow energy conversion processes, which is different from that given by conventional classical thermodynamics.
TL;DR: In this article, an experimental study has been performed for mixed (solid+gas) fuelled boiler operating at 7000 kPa pressure and 778·15 K temperature with a nominal capacity of 25 kg s−1 in order to find improvement in the boiler efficiency and to reduce its environmental emissions.
Abstract: In this paper, an experimental study has been performed for mixed (solid+gas) fuelled boiler operating at 7000 kPa pressure and 778·15 K temperature with a nominal capacity of 25 kg s−1 in order to find improvement in the boiler efficiency and to reduce its environmental emissions. In this scope, while the boiler was working under operating conditions, temperature, pressure, velocity, and combustion gas measurements were performed and the measured data were used to establish mass and energy balance. Main efficiency loses were identified as operation of the boiler with high excess air factor (39·78%), leakage air in the rotary air hater and surface thermal losses. Calculations, were performed with the use of measured data, estimated that the boiler and second law efficiency were calculated as 85·3 and 39·6% respectively. When the injected heat value on water is 67 433·65 kW in the boiler, by the reduction of excess air factor is 550 kW and by the prevention of leakage air is 1251·6 kW, including to...
TL;DR: In this paper, a late mixing porous burner (LMPB) that is safe to operate with preheating zone of fuel and air mixture, resulting in an increase in the thermal efficiency, is studied.
Abstract: In this work, the new concept of a late mixing porous burner (LMPB) that is safe to operate with preheating zone of fuel and air mixture, resulting in an increase in the thermal efficiency, is studied. This is unlike conventional premixed porous burner technology, where the fuel and air are mixed early and have only a mixture preheated zone. The numerical model is calculated based on a single step global reaction, a steady state approach and a local thermal non-equilibrium between gas and solid phase. The results of the numerical model are validated by comparison with experimental data. Results from the simulation emphatically agree with the experimental data. The modelling can predict the burner performance at various operating conditions. Furthermore, modelling can also provide importation information; for example, it predicts the equivalence ratio and firing rate. This indicates that the LMPB achieved higher heat recirculation efficiency and higher radiant output efficiency compared with the co...
TL;DR: In this paper, the second law approach has been used to evaluate component wise exergy destruction for different values of investigated parameters and the effect of varying values of air/fuel ratio and compression ratio on the performance parameters like component-wise percentage exergy degradation and rational efficiency of gas turbine and steam turbine.
Abstract: The paper presents exergy analysis of a gas/steam combined cycle also called gas turbine combined cycle. The second law approach has been used to evaluate component wise exergy destruction for different values of investigated parameters. The cycle components, i.e. compressor, gas turbine (high pressure and low pressure), combustor, heat recovery steam generator (HRSG), stack, steam turbine and water cooled condenser have been investigated with respect to the effect of varying values of air/fuel ratio and compression ratio on the performance parameters like component-wise percentage exergy destruction and rational efficiency of gas turbine and steam turbine and the results have been presented. Results show that higher values of compression ratio and low air/fuel ratio correspond to lower exergy destruction associated with combustion. The effect of turbine exit temperature on the rational efficiency of plant has been discussed. It has been concluded that for maximising plant efficiency, turbine inle...
TL;DR: In this article, an experimental study was performed to analyse the emission of hydrophilic particulates in nanometre size range in the exhaust gas of a small non-road gasoline engine.
Abstract: An experimental study has been performed to analyse the emission of hydrophilic particulates in nanometre size range in the exhaust gas of a small non-road gasoline engine. Such engines are widely used in agricultural and farmland applications, and emission from them is receiving serious attention from environment protection agencies in recent times. The engine coupled with an eddy current dynamometer was operated at different loads while maintaining the speed constant. A small portion of the exhaust gas was extracted and passed through deionised water to disperse any hydrophilic substance to form a colloidal suspension. Any volatile compound and low boiling point liquid are removed from the samples by continuous sparging before analysis. Absorption and fluorescence studies of the hydrosol confirm the existence of combustion generated nanosized soot precursor particles in the sample. The particle size distributions at different loads were studied using dynamic light scattering, and the number conc...
TL;DR: In this paper, the authors investigated the performance of a through flow (TF) wave rotor for the potential of application in gas turbine or engine and found that it has good efficiency ranging from middle to even higher compression pressure ratios.
Abstract: The wave rotor is a pressure exchanger utilising direct pressure transfer between fluids by pressure waves. This paper presents the investigation of the performance of a through flow (TF) wave rotor for the potential of application in gas turbine or engine. A test rig was built to test the performance of the TF wave rotor, which was tested in different conditions. The wave rotor ran at different speeds, while the supplies of air and fuel were kept the same. The results show that the TF wave rotor has good efficiency ranging from middle to even higher compression pressure ratios. In addition, the rotor speed has great effects on its performance. Both the pressure and temperature of hot gas have great influence on its performance. The effect of gas temperature is more important. It is useful to improve the wave rotor efficiency by increasing the gas temperature.
TL;DR: In this paper, the shape of charge was converted to SC and used liquid petroleum gases (LPG) fuel, and the mixture was taken into the engine as stratified by two steps.
Abstract: The energy conversation and values of limited emission level are very important issue for manufacturers and engine designers. Therefore the investigations about homogeneous charge engine and stratified charge (SC) engine have commonly been considered by the literatures. Homogeneous charge engines run with stoichiometric mixture, and SC engines run with lean mixture. The main purpose of this study, in order to run with poor mixture of gasoline engine like diesel engine, the shape of charge was converted to SC and used liquid petroleum gases (LPG) fuel. In this point of view, LPG–air mixture is prepared in two different environments and rates, and the mixture was taken into the engine as stratified by two steps. The effects of engine performance, fuel consumption and emission characteristics are investigated for SC application. The experiments were made under full load and full throttle position. According to the results of the experiments, both the engine power and torque did not change and the fuel consum...
TL;DR: In this article, energy and exergy analyses are carried out for a double effect series flow type absorption cooling system with different high temperature generator (HTG) pressures, and the results are compared for a 1 kg s−1 coolant, where LiBr-H2O is chosen as the working fluid pair.
Abstract: In this paper, energy and exergy analyses are carried out for a double effect series flow type absorption cooling system with different high temperature generator (HTG) pressures. In the cases, the pressure of HTG is selected as 100, 70 and 50 kPa respectively. Thermal loads of each component, mass flowrates of each stream, coefficient of performance (COP), exergy destruction of each component and second law efficiency are calculated, and the results are compared for a 1 kg s−1 coolant, where LiBr–H2O is chosen as the working fluid pair. In increasing the pressure of HTG, the COP increases. At the same time, the exergy efficiency and the mass flowrate of steam, which are necessary to drive the cooling system, decrease. The COP and the second law efficiency are calculated as 1·215 and 9·5% for 100 kPa HTG pressure. Exergy destruction ratio, exergy loss ratio and exergy improvement potential of the system components are calculated. The highest irreversibility is found in the absorber, and the exergy...
TL;DR: In this article, the best ignition timing for an SI engine with the use of E10 ethanol blend was experimentally investigated and it was generally observed that overall efficiency increases with advanced ignitions.
Abstract: In this study, the best ignition timing for an SI engine with the use of E10 ethanol blend was experimentally investigated. Ignition timing was retarded successively by 2° up to 6° at most (denoted as −2, −4 and −6 respectively) and then advanced by 2° successively up to 6° (denoted as +2, +4 and +6 respectively) with respect to the advance values realised with gasoline (termed as ‘original advance values’) at full load operation. It was generally observed that overall efficiency increases with advanced ignitions. The best performance and emissions were obtained with +4. This increase amounts to 6% for 4° advanced ignition at 3000 rev min−1. Advanced ignition timing resulted with increase in NOx emissions, while CO and CO2 remained relatively unaffected. Increasing retard in ignition timing caused poorer combustion and hence more fuel consumption but less hydrocarbon emissions.
TL;DR: In this paper, the authors examined an industrial burner by numerically simulating the fuel particle flows in the tube leading to the burner mouth, and concluded from the flame data that this effect does not significantly influence the combustion flame in the furnace.
Abstract: The co-combustion of pulverised coal and biomass is increasingly being used for environmental reasons, and a number of computational fluid dynamic investigations are being undertaken to understand the details of the combustion process. These investigations assume that the particle flow entering the burner is uniformly distributed across the burner mouth or inlet. In this paper, this assumption is examined for an industrial burner by numerically simulating the fuel particle flows in the tube leading to the burner mouth. While there is evidence of maldistribution of the particles at the burner mouth, it is concluded from the flame data that this effect does not significantly influence the combustion flame in the furnace for the cases investigated.
TL;DR: In this article, two different ceramic materials, namely, Al2O3 and ZrO2, were used separately to create thermal insulation on the cylinder head to a thickness of 300 μm.
Abstract: The objective of the present work is to partially insulate the combustion chamber of an SI engine using two different ceramic materials and investigate its effect on engine performance and exhaust emissions. Two different ceramic materials, namely, alumina (Al2O3) and partially stabilised zirconia (ZrO2), were used separately to create thermal insulation on the cylinder head to a thickness of 300 μm. The engine was fuelled with 15% ethanol–85% gasoline blend (E15). The experimental results of alumina and zirconia coated engine were compared with baseline unmodified engine. The results show that both the partially insulated engines improve brake thermal efficiency and reduce exhaust emission. Around 20% reduction in hydrocarbon and 23% reduction in carbon monoxide emission from baseline values were achieved at part loads. However, ∼30% increase in NOx emission was observed at higher loads in partially insulated engines. Significant changes in performance and exhaust emission between alumina and zirconia co...