Experimental investigation on a C.I. engine using orange oil and orange oil with DEE

In the present work, the effect of using neat orange oil, optimum orange oil-diesel blend and the optimum flow rate of DEE with orange oil are evaluated for the performance, emissions and combustion characteristics of a single cylinder, diesel engine. The experimental results show that carbon monoxide (CO), hydrocarbon (HC) and smoke emissions decrease while oxides of nitrogen (NO_x) emissions increase for orange oil and its blends compared to diesel fuel and DEE with orange oil. The brake thermal efficiency in the case of DEE with orange oil is higher than that of orange oil, orange oil-diesel fuel blend and diesel fuel. The peak cylinder pressure and heat release rate for DEE with orange oil are higher than those of diesel fuel operation.     

Combustion performance and emissions of petrodiesel and biodiesels based on various vegetable oils in a semi industrial boiler

This paper intends to investigate combustion of petrodiesel and biodiesels of grape seed, corn, sunflower, soybean, olive and rice bran oils, which were produced through an alkali-based transesterification, in a non-pressurized, water-cooled combustion chamber by determining its combustion performance and gas emissions (CO, CO₂, NO_x, SO₂). First, the influence of fuel pressure which related to the rate of sprayed fuel to the chamber was studied in order to find out an optimum combustion pressure. In the next level, the influence of A/F upon emissions and boiler performances at 13.79 bars was studied. Results show that similar combustion of fuels occurred at 13.79 bars (optimum) where due to the increase in fuel pressure, the effect of viscous forces in flame formation disappeared. Complete combustion of fuels occurred at 19.305 bars where the CO emissions of all the fuels reached to zero.The overall performance of the boiler obtained with the methyl esters and petrodiesel are comparable for the defined operating points (especially at high energy rates and low A/F). All the six kinds of vegetable based methyl ester emitted lower emissions than petrodiesel over the wide fuel pressures, and A/F. Meanwhile, biodiesels emitted higher amounts of NO_x than petrodiesel. Biodiesels also emitted higher amounts of CO than petrodiesel at low fuel pressures when the viscous forces interfered with proper distributions of fuels to the combustion chamber.     

Combustion and air emissions from co‐firing a wood biomass,a Canadian peat and a Canadian lignite coal in a bubbling fluidised bed combustor

The effects of particle size, fuel blending ratio, moisture content and excess air ratio on combustion efficiency and air emissions (CO₂, CO, SO₂ and NO_x) from the co‐combustion of white pine or peat with a Canadian lignite coal, were examined in a pilot‐scale bubbling fluidised bed combustor. Pelletising was important for the efficient combustion of wood due to its high volatile content. Co‐firing lignite and pine pellets gave a proportional reduction in SO₂ and NO_x emissions with blending ratio, while co‐firing of peat and lignite resulted in increased SO₂ emissions, but decreased NO_x emissions. Moisture promotes combustion but with increased CO emissions, and results in increased NO_x emissions, and decreased SO₂ emissions. High excess air decreased CO, but moderately increased SO₂ and NO_x emissions. © 2011 Canadian Society for Chemical Engineering     

Testing the performance and compatibility of degummed soybean heating oil blends for use in residential furnaces

Degummed soybean heating oil (SHO) is a renewable energy resource, which can reduce dependence on foreign oil and create a new market for the soybean industry. This study demonstrated that SHO 20 (20% degummed soybean oil and 80% No. 2 fuel oil) is suitable for application in residential furnaces without modification. The tests conducted were: fuel properties, seal compatibility, long-term storage, and laboratory and field combustion. The physical property tests showed that the kinematic viscosity (0.0346 cm²/s) and the pour point of SHO 20 (−30 °C) were within the ASTM requirement for No. 2 fuel oil; and the net heating value of SHO 20 (43.9 MJ/kg) was only 1-3% lower than the No. 2 fuel oil value (45.6 MJ/kg). Compatibility tests performed on the rubber seals and gasket materials (Nitrile and Viton) found in typical heating fuel pump systems indicated that the tensile strength and hardness values were not significantly affected by SHO blends when compared with No. 2 fuel oil. A long-term storage test revealed that there was no significant change in heat content and no visible stratification of SHO 20 blend during three months of storage. The pump pressure and the type of nozzle used affected the concentration of NO_x, SO₂, and CO in the flue gas. As was expected, increasing the SHO fraction in the blend also reduced the SO₂ emission. The combustion of SHO 20 resulted in a higher flue gas temperature which increased the NO_x emission than with No. 2 fuel oil.     

Experimental study on effects of operating conditions and fuel quality on thermal efficiency and emission performance of a 300-MW boiler unit firing Thai lignite

This paper presents the results of an experimental study on a 300-MW boiler unit fired with Thai lignite. Effects of operating conditions (excess air ratio and unit load) and fuel quality on the boiler heat losses and thermal efficiency as well as on the gaseous (CO₂, CO, NO_x and SO₂) and particulate matter (PM) emissions from the boiler unit are discussed. The boiler thermal efficiency was weakly affected by the excess air ratio, unit load and fuel lower heating value, varying from 90.3 to 92.3% for wide ranges of the above variables. In all the tests, the NO_x, SO₂ and PM emissions were below the national emission standards for these pollutants. Quite low level of the SO₂ emission was secured by the high-efficiency flue gas desulphurization system. The CO emissions of rather small values were detected only at extremely low excess air ratios. The emission rate and specific emission (i.e. per MWh of electricity produced) for NO_x, SO₂ and CO were quantified using experimental emission concentrations of the pollutants. Meanwhile, the emission characteristics for CO₂ were determined with the use of fuel-C and fuel consumption by the boiler. In addition, the emission rate and specific emission for PM were estimated by taking into account the actual fuel-ash content and fuel consumption by the boiler, as well as the effects of SO₂ adsorption by fly ash in the boiler gas ducts and overall ash-collecting efficiency of the electrostatic precipitators and flue gas desulphurization system. Elevated CO₂ and NO_x emissions from the 300-MW boiler units firing Thai lignite are of great concern.     

Analysis of the behaviour of pollutant gas emissions during wheat straw/coal cofiring by TG-FTIR

The behaviour of pollutant gas emissions during the firing of wheat straw and coal blends was examined experimentally by using thermogravimetric analysis (TGA). Typical anthracite coal and wheat straw in central China were selected in this study. The ratio of coal to wheat straw by mass was set as 10:90, 15:85, 40:60 and 60:40 and the firing was carried using simulated air with oxygen and nitrogen gases. The emission characteristics of gas pollutants such as HCl, SO₂, CO₂ and NO_x were determined by coupled Fourier transform infrared (FTIR) measurements. The results showed that HCl, SO₂, CO₂ and NO_x emissions were closely related to the volatile combustion and char reacting stages. HCl emission was mainly released during the volatile combustion at the temperature between 220 and 450 °C. The profiles of HCl against temperature exhibit a single-peak, and the HCl peak occurred at 310 °C for all blends no matter what the ratio. The emission profiles of SO₂, and NO_x against temperature had the characteristic of two peaks. The first peak occurred around 320 °C for all blends, and however the second peak shifted towards higher temperatures as the coal content was increased in the blends. The study showed that combining the straw and coal can produce better emission control by reducing the magnitude of the peak releases. The analysis showed that the blended sample with 40% coal and 60% straw by mass produced the lowest levels of HCl, NO_x and SO₂ gas emissions. The CO₂ emission was mainly produced in the char combustion stage and purely increased with the carbon content in the blends.     

Experimental investigation of NOx emissions in oxycoal combustion

This work presents the results of an experimental investigation on NO_x emissions from coal combustion in a pilot scale test facility. Three oxidiser atmospheres have been compared, namely air, CO₂/O₂, and O₂ enriched recirculated flue gas. NO_x emissions from two different combustion modes have been studied, swirl flame and flameless combustion. The influence of the burner oxygen ratio and the oxidiser O₂ concentration on NO_x formation and reduction have been analysed. With increasing burner oxygen ratio, an increase of NO_x emissions has been obtained for air and CO₂/O₂ in both, swirl flame and flameless combustion. In case of the swirl flame, flue gas recirculation leads to a reduction of NO_x emissions up to 50%, whereas in case of flameless combustion this reduction is around 40% compared to CO₂/O₂. No significant impact of the oxidiser O₂ concentration in the CO₂/O₂ mixture on NO_x emissions is observed in the range between 18 and 27 vol.% in swirl flames. An analysis of NO_x formation and reduction mechanisms showed, that the observed reduction of NO_x emissions by flue gas recirculation cannot be attributed to the reduction of recirculated NO_x alone, but also to a reduced conversion of fuel-N to NO.     

Performance, emission and combustion evaluation of soapnut oil-diesel blends in a compression ignition engine

Soapnut (Sapindus mukorossi) oil, a nonedible straight vegetable oil was blended with petroleum diesel in various proportions to evaluate the performance and emission characteristics of a single cylinder direct injection constant speed diesel engine. Diesel and soapnut oil (10%, 20%, 30% and 40%) fuel blends were used to conduct short-term engine performance and emission tests at varying loads in terms of 25% load increments from no load to full loads. Tests were carried out for engine operation and engine performance parameters such as fuel consumption, brake thermal efficiency, and exhaust emissions (smoke, CO, UBHC, NO_x, and O₂) were recorded. Among the blends SNO 10 has shown a better performance with respect to BTE and BSEC. All blends have shown higher HC emissions after about 75% load. SNO 10 and SNO 20 showed lower CO emissions at full load. NO_x emission for all blends was lower and SNO 40 blend achieved a 35% reduction in NO_x emission. SNO 10% has an overall better performance with regards to both engine performance and emission characteristics.     

Performance and emission characteristics of an CI engine fueled with diesel–biodiesel–bioethanol blends

The paper presents the experimental results obtained concerning performances and pollution of a diesel engine fueled with diesel–biodiesel–ethanol blends compared with diesel fuel in laboratory tests. The main properties of the researched fuels are presented within this paper, in comparison with classical diesel fuel (chemical composition, density, kinematic viscosity, cold filter plugging point, flash point). Engines’ performances were evaluated by determining the brake specific fuel consumption and brake thermal efficiency. For pollution evaluation the emissions of CO, CO₂, NO_x, HC and smoke have been measured. An increasing of brake specific fuel consumption has been observed, especially at lower engines’ loads, with maximum 32.4%, reducing engine brake thermal efficiency with maximum 21.7%. CO emissions decrease, especially at high loads with maximum 59%, on the basis of CO₂ increased emissions. NO_x emissions slightly increase, especially at partial and high loads, meanwhile HC and smoke emissions decrease in all engines’ load cycles.     

Comparisons of pulverized coal combustion in air and in mixtures of O2/CO2

Pulverized coal combustion in air and the mixtures of O₂/CO₂ has been experimentally investigated in a 20 kW down-fired combustor (190 mm id×3 m). Detailed comparisons of gas temperature profiles, gas composition profiles, char burnouts, conversions of coal–N to NO_x and coal–S to SO₂ and CO emissions have been made between coal combustion in air and coal combustion in various O₂/CO₂ mixtures. The effectiveness of air/oxidant staging on reducing NO_x emissions has also been investigated for coal combustion in air and O₂/CO₂ mixtures. The results show that simply replacing the N₂ in the combustion air with CO₂ will result in a significant decrease of combustion gas temperatures. However, coal combustion in 30% O₂/70% CO₂ can produce matching gas temperature profiles to those of coal combustion in air while having a lower coal–N to NO_x conversion, a better char burnout and a lower CO emission. The results also confirm that air/oxidant staging is very effective in reducing NO_x emissions for coal combustion in both air and a 30% O₂/70% CO₂ mixture. SO₂ emissions are proved to be almost independent of the combustion media investigated.     

Effects of dimethyl-ether (DME) spray behavior in the cylinder on the combustion and exhaust emissions characteristics of a high speed diesel engine

The purpose of this study was to analyze the exhaust emissions of DME fuel through experimental and numerical analyses of in-cylinder spray behavior. To investigate this behavior, spray characteristics such as the spray tip penetration, spray cone angle, and spray targeting point were studied in a re-entrant cylinder shape under real combustion chamber conditions. The combustion performance and exhaust emissions of the DME-fueled diesel engine were calculated using KIVA-3V. The numerical results were validated with experimental results from a DME direct injection compression ignition engine with a single cylinder.The combustion pressure and IMEP have their peak values at an injection timing of around BTDC 30°, and the peak combustion temperature, exhaust emissions (soot, NO_x), and ISFC had a lower value. The HC and CO emissions from DME fuel showed lower values and distributions in the range from BTDC 25° to BTDC 10° at which a major part of the injected DME spray was distributed into the piston bowl area. When the injection timing advanced to before BTDC 30°, the HC and CO emissions showed a rapid increase. When the equivalence ratio increased, the combustion pressure and peak combustion temperature decreased, and the peak IMEP was retarded from BTDC 25° to BTDC 20°. In addition, NO_x emissions were largely decreased by the low combustion temperature, but the soot emissions increased slightly.     

Diesel engine performance and emission characteristics of biodiesel produced by the peroxidation process

Biodiesel is an alternative fuel that is cleaner than petrodiesel. Biodiesel can be used directly as fuel for a diesel engine without having to modify the engine system. It has the major advantages of having high biodegradability, excellent lubricity and no sulfur content. In this study, the biodiesel produced by a transesterification technique was further reacted by using a peroxidation process. Four types of diesel fuel, biodiesel with and without an additional peroxidation process, a commercial biodiesel and ASTM No. 2D diesel were compared for their fuel properties, engine performance and emission characteristics. The experimental results show that the fuel consumption rate, brake thermal efficiency, equivalence ratio, and exhaust gas temperature increased while the bsfc, emission indices of CO₂, CO and NO_x decreased with an increase of engine speed. The three biodiesels showed a higher fuel consumption rate, bsfc, and brake thermal efficiency, while at the same time exhibited lower emission indices of CO and CO₂ as well as a lower exhaust gas temperature when compared to ASTM No. 2D diesel. Moreover, the biodiesel produced with the additional peroxidation process was found to have an oxygen content, weight proportion of saturated carbon bonds, fuel consumption rate, and bsfc that were higher than the biodiesel produced without the additional process; while at the same time the brake thermal efficiency, equivalence ratio, and emission indices of CO₂, CO and NO_x were found to be lower. In particular, biodiesel produced with the addition of the peroxidation process had the lowest equivalence ratio and emission indices of CO₂, CO and NO_x among all of the four test fuels. Therefore, the peroxidation process can be used to effectively improve the fuel properties and reduce emissions when biodiesel is used.     

Study on the application of DME/diesel blends in a diesel engine

In this paper fuels, based on various DME to diesel ratios are investigated. Physical and chemical properties of DME and diesel display mutual solubility at any ratio. The vapor pressure of DME/diesel blends is lower than that of pure DME at the same temperatures and it decreases with an increase of diesel mass fraction in blends, which is beneficial to the elimination of vapor lock in the fuel supply system on CI engines. Performance, emission and other features of three kinds of DME/diesel blend fuels and diesels are evaluated in a four-cylinder test engine. By taking relative advantages of DME and diesel, the DME/diesel blends could achieve satisfactory properties in lubricity and atomization, which contributed to improvements in spray and combustion characteristics. Simultaneously, smoke emission could be reduced significantly with a little penalty on CO and HC emissions for DME/diesel blended engine at high loads, in comparison to diesel engine. NO_x emissions of the engine powered by DME/diesel blends are decreased somewhat. Moreover, the power output would be improved a little and NO_x emission could be reduced further if the fuel supply advance angle is retarded appropriately.     

Use of syngas as an auto fuel additive: State of the art and prospects

A method for the production of a hydrogen-rich gas on board a vehicle was suggested and driving- and bench-tested for application in studies on energy-efficient internal combustion engines with minimum CO, CO₂, CH, and NO _x emissions. The generated gas is further added to the main fuel fed to the engine. Catalysts for hydrocarbon fuel conversion to syngas were developed. A compact on-board syngas generator mounted under the motor hood and a generator control system adapted to the engine control system were designed. It was shown experimentally that the suggested solution allows a reduction of 13–40% in the fuel rate depending on the operating mode under the urban cycle conditions and considerably decreases the release of CO, CO₂, and NO _x . Prospects for the applications of this technology for creating ecologically clean engines were assessed.     

Feasibility of blending karanja vegetable oil in petro-diesel and utilization in a direct injection diesel engine

Karanja (Pongamia pinnata) oil, a non-edible high viscosity (27.84 cSt at 40 °C) straight vegetable oil, was blended with conventional diesel in various proportions to evaluate the performance and emission characteristics of a single cylinder direct injection constant speed diesel engine. Diesel and karanja oil fuel blends (5%, 10%, 15%, and 20%) were used to conduct short-term engine performance and emission tests at varying loads (0%, 20%, 40%, 60%, 80%, and 100%). Tests were carried out over the entire range of engine operation and engine performance parameters such as fuel consumption, thermal efficiency, exhaust gas temperature, and exhaust emissions (smoke, CO, CO₂, HC, NO_x, and O₂) were recorded. The brake specific energy consumption (BSEC), brake thermal efficiency (BTE), and exhaust emissions were evaluated to determine the optimum fuel blend. Higher BSEC was observed at full load for neat petro-diesel. A fuel blend of 10% karanja oil (KVO10) showed higher BTE at a 60% load. Similarly, the overall emission characteristics were found to be best for the case of KVO10 over the entire range of engine operation.     

Exhaust emissions and fuel properties of partially hydrogenated soybean oil methyl esters blended with ultra low sulfur diesel fuel

Important fuel properties and emission characteristics of blends (20 vol.%) of soybean oil methyl esters (SME) and partially hydrogenated SME (PHSME) in ultra low sulfur diesel fuel (ULSD) were determined and compared with neat ULSD. The following changes were observed for B20 blends of SME and PHSME versus neat ULSD: improved lubricity, higher kinematic viscosity and cetane number, lower sulfur content, and inferior low-temperature properties and oxidative stability. With respect to exhaust emissions, B20 blends of PHSME and SME exhibited lower PM and CO emissions in comparison to those of neat ULSD. The PHSME blend also showed a significant reduction in THC emissions. Both SME and PHSME B20 blends yielded small increases in NO_x emissions. The reduction in double bond content of PHSME did not result in a statistically significant difference in NO_x emissions versus SME at the B20 blend level. The test engine consumed a greater amount of fuel operating on the SME and PHSME blends than on neat ULSD, but the increase was smaller for the PHSME blend.     

Combustion, performance and emission characteristics of a DI diesel engine fueled with ethanol-biodiesel blends

In this study, Euro V diesel fuel, biodiesel, and ethanol-biodiesel blends (BE) were tested in a 4-cylinder direct-injection diesel engine to investigate the combustion, performance and emission characteristics of the engine under five engine loads at the maximum torque engine speed of 1800 rpm. The results indicate that when compared with biodiesel, the combustion characteristics of ethanol-biodiesel blends changed; the engine performance has improved slightly with 5% ethanol in biodiesel (BE5). In comparison with Euro V diesel fuel, the biodiesel and BE blends have higher brake thermal efficiency. On the whole, compared with Euro V diesel fuel, the BE blends could lead to reduction of both NO_x and particulate emissions of the diesel engine. The effectiveness of NO_x and particulate reductions increases with increasing ethanol in the blends. With high percentage of ethanol in the BE blends, the HC, CO emissions could increase. But the use of BE5 could reduce the HC and CO emissions as well.     

Improvement of combustion efficiency and reduction of NO x emission by external oscillation of reactants in an oil burner

The important requirement for the development of burners is the achievement of low emissions, particularly NO _x , while maintaining high combustion efficiency. In this work, an externally oscillated oil burner was developed which provides both high-efficiency combustion and low NO _x emission simultaneously. To investigate combustion characteristics and NO _x emission, parametric studies were carried out about oscillation frequency, forcing amplitude, and air velocity. Optimum combustion was achieved at frequency of 1,900 Hz, amplitude of 3 V _pp , and air velocity of 6.8 m/s. The NO _x and CO emissions were reduced by 47% and 22%, respectively. In particular, the mechanism responsible for the inherently low NO _x emission levels from an externally oscillated oil burner has been shown to be a short residence time at high temperature caused by rapid mixing with cooler residual gases.     

Exhaust emissions from a diesel powered vehicle fuelled by soybean biodiesel blends (B3-B20) with ethanol as an additive (B20E2-B20E5)

The effects of diesel oil-soybean biodiesel blends on a passenger vehicle exhaust pollutant emissions were investigated. Blends of diesel oil and soybean biodiesel with concentrations of 3% (B3), 5% (B5), 10% (B10) and 20% (B20) were used as fuels. Additionally, the effects of anhydrous ethanol as an additive to B20 fuel blend with concentrations of 2% (B20E2) and 5% (B20E5) were also studied. The emissions tests were carried out following the New European Driving Cycle (NEDC). The results showed that increasing biodiesel concentration in the fuel blend increases carbon dioxide (CO₂) and oxides of nitrogen (NO_X) emissions, while carbon monoxide (CO), hydrocarbons (HC) and particulate matter (PM) emissions are reduced. The addition of anhydrous ethanol to B20 fuel blend proved it can be a strategy to control exhaust NO_X and global warming effects through the reduction of CO₂ concentration. However, it may require fuel injection modifications, as it increases CO, HC and PM emissions.     

Co-combustion of rice husk with coal in a cyclonic fluidized-bed combustor (ψ-FBC)

Thailand is well-endowed with renewable energy resources. In Thailand, rice husk, a by-product of the rice-milling process and one of the most potentially sustainable cultivated biomasses, has an annual energy equivalent of 6.6 × 10⁷ GJ. Using rice husk alone, however, can be problematic, particularly if there is a deficit during the off-season. Coal, the most abundant fossil fuel, has thus been considered an appropriate supplementary fuel. This paper describes the combustion characteristics of co-firing rice husk with bituminous coal in a 120 kW_th-capacity cyclonic fluidized-bed combustor (ψ-FBC), and how excess air ratios and fuel blends impacted emissions and combustion efficiency (E_c). Overall, excess air and blending ratios did not have tremendous effects on E_c, easily achieving >97%. Radial temperature profiles revealed that vortex combustion prevailed along the combustor walls. Concurring with axial temperature profiles, axial O₂ profiles suggested that the combustion was confined chiefly to regions under the vortex ring. Despite massive CO production in the lower section, CO emissions were satisfactory (range 60-260 ppm, at 6% O₂). Due to the high bed temperatures, NO_x appeared rather high (260-416 ppm, at 6% O₂). Not only were NO_x emissions affected by coal ratio, it were also highly reliable on the operating conditions. SO₂ emissions varied directly, but not proportionally, with the sulfur content of the fuel mixture.