Some Studies on NOX Reduction From a Diesel Engine Using Stabilized Emulsion

2018 ◽  
Author(s):  
Naveen Kumar ◽  
Harveer Singh Pali ◽  
Sidharth Bansal
Keyword(s):  
Diesel Engine ◽  
Water Content ◽  
Volume Fraction ◽  
Nox Reduction ◽  
Flame Temperature ◽  
Water Volume ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Engine Operation ◽  
Water Emulsion

The twentieth century has seen a rapid twenty-fold increase in the use of fossil fuels. Personal and commercial transportation consumes 2% of the total world energy. The main products of combustion of fossil fuel are carbon mono oxide (CO), unburned hydrocarbons (HC), Carbon dioxide (CO2), oxides of sulfur (SOx), oxides of nitrogen (NOx) and particulate matter. Oxides of nitrogen (NOx) are the major diesel engine pollutants and referred to as mixtures of nitric oxide (NO) and nitrogen dioxide (NO2). NOx emissions are required to be controlled because NO and NO2 contribute to the formation of smog, an environmental and human health hazard. NO2 is also directly of concern as a human lung aggravation. To reduce NOx emissions from a diesel engine, the introduction of water in the combustion chamber of a diesel engine is a promising option as vaporization of water reduces adiabatic flame temperature and micro-explosion phenomena lead to improved mixing. In the present study, stable D/W emulsion, with varying water content, up to 3% were prepared using span 80 as a surfactant. The results indicated a reduction in NOx and smoke with increasing water volume fraction in the emulsion compared to diesel baseline. However, beyond 2% water content led to increased ignition delay and higher diffusion phase heat release resulting in noisy engine operation. Therefore, it can be concluded that diesel-water emulsion with 2% water could be used for significant reduction of NOx emissions from diesel and biodiesel operation of a CI Engine.

Stabilizing Excessive EGR With an Oxidation Catalyst on a Modern Diesel Engine

2002 ◽  
Author(s):  
Ming Zheng ◽  
David K. Irick ◽  
Jeffrey Hodgson
Keyword(s):  
Diesel Engine ◽  
Oxidation Catalyst ◽  
Stable Operation ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Engine Operation ◽  
Turbocharged Diesel Engine ◽  
New Approach ◽  
Cyclic Variations ◽  
Gas Recirculation

For diesel engines (CIDI) the excessive use of exhaust gas recirculation (EGR) can reduce in-cylinder oxides of nitrogen (NOx) generation dramatically, but engine operation can also approach zones with high instabilities, usually accompanied with high cycle-to-cycle variations and deteriorated emissions of total hydrocarbon (THC), carbon monoxide (CO), and soot. A new approach has been proposed and tested to eliminate the influences of recycled combustibles on such instabilities, by applying an oxidation catalyst in the high-pressure EGR loop of a turbocharged diesel engine. The testing was directed to identifying the thresholds of stable operation at high rates of EGR without causing cycle-to-cycle variations associated with untreated recycled combustibles. The elimination of recycled combustibles using the oxidation catalyst showed significant influences on stabilizing the cyclic variations, so that the EGR applicable limits are effectively extended. The attainability of low NOx emissions with the catalytically oxidized EGR is also evaluated.

scholarly journals Effects of Oxygenated Additives with Diesel on the Performance of D I Diesel Engine

2019 ◽  
pp. 1-9 ◽  
Author(s):  
P. Venkateswara Rao ◽  
S. Ramesh ◽  
S. Anil Kumar
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Direct Injection ◽  
Primary Objective ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Smoke Emission ◽  
Oxygenated Additives ◽  
Blend Fuel ◽  
Fuel Formulation

The primary objective of this work is to reduce the particulate matter (PM) or smoke emission and oxides of nitrogen (NOx emissions) the two important harmful emissions and to increase the performance of diesel engine by using oxygenated additives with diesel as blend fuel. Formulation of available diesel fuel with additives is an advantage than considering of engine modification for improvement of higher output. From the available additives, three oxygenates are selected for experimentation by considering many aspects like cost, content of oxygen, flashpoint, solubility, seal etc. The selected oxygenates are Ethyl Aceto Acetate (EAA), Diethyl Carbonate (DEC), Diethylene Glycol (DEG). These oxygenates are blended with diesel fuel in proportions of 2.5%, 5% and 7.5% by volume and experiments were conducted on a single cylinder naturally aspirated direct injection diesel engine. From the results the conclusion are higher brake power and lower BSFC obtained for DEC blends at 7.5% of additive as compared to EAA, DEG and diesel at full load. In case of DEC blends the smoke emission is lower, whereas NOx emissions are very low in case of EAA additive blend fuels. The DEC can be considered is the best oxygenating additive to be blend with diesel in a proportion of 7.5% by volume.

scholarly journals Influence of Fuel Injection Pressure on the Emissions Characteristics and Engine Performance in a CRDI Diesel Engine Fueled with Palm Biodiesel Blends

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3837 ◽  
Author(s):  
Sam Ki Yoon ◽  
Jun Cong Ge ◽  
Nag Jung Choi
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Biodiesel Fuel ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Fuel Blend ◽  
Engine Load ◽  
Fuel Injection Pressure

This experiment investigates the combustion and emissions characteristics of a common rail direct injection (CRDI) diesel engine using various blends of pure diesel fuel and palm biodiesel. Fuel injection pressures of 45 and 65 MPa were investigated under engine loads of 50 and 100 Nm. The fuels studied herein were pure diesel fuel 100 vol.% with 0 vol.% of palm biodiesel (PBD0), pure diesel fuel 80 vol.% blended with 20 vol.% of palm biodiesel (PBD20), and pure diesel fuel 50 vol.% blended with 50 vol.% of palm biodiesel (PBD50). As the fuel injection pressure increased from 45 to 65 MPa under all engine loads, the combustion pressure and heat release rate also increased. The indicated mean effective pressure (IMEP) increased with an increase of the fuel injection pressure. In addition, for 50 Nm of the engine load, an increase to the fuel injection pressure resulted in a reduction of the brake specific fuel consumption (BSFC) by an average of 2.43%. In comparison, for an engine load of 100 Nm, an increase in the fuel injection pressure decreased BSFC by an average of 0.8%. Hydrocarbon (HC) and particulate matter (PM) decreased as fuel pressure increased, independent of the engine load. Increasing fuel injection pressure for 50 Nm engine load using PBD0, PBD20 and PBD50 decreased carbon monoxide (CO) emissions. When the fuel injection pressure was increased from 45 MPa to 65 MPa, oxides of nitrogen (NOx) emissions were increased for both engine loads. For a given fuel injection pressure, NOx emissions increased slightly as the biodiesel content in the fuel blend increased.

Application of Diethyl Ether to Reduce Smoke and NOx Emissions Simultaneously With Diesel and Biodiesel Fueled Engines

2008 ◽  
Author(s):  
Masoud Iranmanesh ◽  
J. P. Subrahmanyam ◽  
M. K. G. Babu
Keyword(s):  
Diesel Engine ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Heating Value ◽  
Simultaneous Reduction ◽  
Performance And Emission ◽  
Oxygenated Fuel ◽  
Di Diesel Engine ◽  
Biodiesel Blend

In this investigation, tests were conducted on a single cylinder DI diesel engine fueled with neat diesel and biodiesel as baseline fuel with addition of 5 to 20% DEE on a volume basis in steps of 5 vol.% as supplementary oxygenated fuel to analyze the simultaneous reduction of smoke and oxides of nitrogen. Some physicochemical properties of test fuels such as heating value, viscosity, specific gravity and distillation profile were also determined in accordance to the ASTM standards. The results obtained from the engine tests have shown a significant reduction in NOX emissions especially for biodiesel and a little decrease in smoke of DEE blends compared with baseline fuels. A global overview of the results has shown that the 5% DEE-Diesel fuel and 15% DEE-Biodiesel blend are the optimal blend based on performance and emission characteristics.

NOx Emissions Modeling and Uncertainty From Exhaust-Gas-Diluted Flames

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Antonio C. A. Lipardi ◽  
Jeffrey M. Bergthorson ◽  
Gilles Bourque
Keyword(s):  
Nox Reduction ◽  
Flame Temperature ◽  
No Production ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Kinetic And Thermodynamic Parameters ◽  
Emissions Modeling ◽  
Combustion Processes ◽  
Gas Recirculation

Oxides of nitrogen (NOx) are pollutants emitted by combustion processes during power generation and transportation that are subject to increasingly stringent regulations due to their impact on human health and the environment. One NOx reduction technology being investigated for gas-turbine engines is exhaust-gas recirculation (EGR), either through external exhaust-gas recycling or staged combustion. In this study, the effects of different percentages of EGR on NOx production will be investigated for methane–air and propane–air flames at a selected adiabatic flame temperature of 1800 K. The variability and uncertainty of the results obtained by the gri-mech 3.0 (GRI), San-Diego 2005 (SD), and the CSE thermochemical mechanisms are assessed. It was found that key parameters associated with postflame NO emissions can vary up to 192% for peak CH values, 35% for thermal NO production rate, and 81% for flame speed, depending on the mechanism used for the simulation. A linear uncertainty analysis, including both kinetic and thermodynamic parameters, demonstrates that simulated postflame nitric oxide levels have uncertainties on the order of ±50–60%. The high variability of model predictions, and their relatively high associated uncertainties, motivates future experiments of NOx formation in exhaust-gas-diluted flames under engine-relevant conditions to improve and validate combustion and NOx design tools.

Effects of Cooled EGR on a Small Displacement Diesel Engine: A Reduced-Order Dynamic Model and Experimental Study

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Christopher Simoson ◽  
John Wagner
Keyword(s):  
Diesel Engine ◽  
Dynamic Model ◽  
Emission Reduction ◽  
Nox Reduction ◽  
Engine Performance ◽  
Small Displacement ◽  
Oxides Of Nitrogen ◽  
Reduced Order ◽  
Reduction Strategies ◽  
Emission Reduction Strategies

Diesel engines are critical in fulfilling transportation and mechanical/electrical power generation needs throughout the world. The engine’s combustion by-products spawn health and environmental concerns, so there is a responsibility to develop emission reduction strategies. However, difficulties arise since the minimization of one pollutant often bears undesirable side effects. Although legislated standards have promoted successful emission reduction strategies for larger engines, developments in smaller displacement engines has not progressed in a similar fashion. In this paper, a reduced-order dynamic model is presented and experimentally validated to demonstrate the use of cooled exhaust gas recirculation (EGR) to alleviate the tradeoff between oxides of nitrogen reduction and performance preservation in a small displacement diesel engine. EGR is an effective method for internal combustion engine oxides of nitrogen (NOx) reduction, but its thermal throttling diminishes power efficiency. The capacity to cool exhaust gases prior to merging with intake air may achieve the desired pollutant effect while minimizing engine performance losses. Representative numerical results were validated with experimental data for a variety of speed, load, and EGR testing scenarios using a 0.697l three-cylinder diesel engine equipped with cooled EGR. Simulation and experimental results showed a 16% drop in NOx emissions using EGR, but experienced a 7% loss in engine torque. However, the use of cooled EGR realized a 23% NOx reduction while maintaining a smaller performance compromise. The concurrence between simulated and experimental trends establishes the simplified model as a predictive tool for diesel engine performance and emission studies. Further, the presented model may be considered in future control algorithms to optimize engine performance and thermal and emission characteristics.

Oxygen Enhanced Exhaust Gas Recirculation for Compression Ignition Engines

2009 ◽  
Author(s):  
Tom Salt ◽  
Dale R. Tree ◽  
Chiwon Kim
Keyword(s):  
Direct Injection ◽  
Flame Temperature ◽  
Exhaust System ◽  
Water Concentration ◽  
Particulate Emissions ◽  
Cylinder Pressure ◽  
Engine Operation ◽  
Water Emulsion ◽  
Specific Heats ◽  
Oxygen Enhancement

The benefits of oxygen enhancement in conjunction with EGR on emissions were investigated in a single-cylinder direct injection diesel engine. Cylinder pressure, NOx, and particulate were measured for EGR sweeps with and without oxygen enhancement. In all cases, the total flow of oxygen to the cylinder was maintained constant. This was achieved by increasing cylinder pressure for typical EGR (N-EGR) and by adding oxygen to the intake stream for oxygen-enhanced EGR (O-EGR). The results show that O-EGR produced a substantially better combination of NOx and particulate than N-EGR. In the N-EGR cases, the EGR dilutes the oxidizer causing lower NOx and higher particulate. In O-EGR, flame temperature reduction leading to lower NOx is achieved by a combination of higher molar specific heats of CO2 and H2O and dilution. Particulate emissions decreased or remain constant with increasing O-EGR. In addition to the obvious challenge of providing a source oxygen to an engine, two operational challenges were encountered. First, as EGR was increased, the ratio of specific heats (Cp/Cv) of the cylinder intake charge decreased and decreased the compression temperature, causing significant changes in ignition delay. These changes were compensated for in the experiments by increasing intake temperature but would be challenging to manage in transient engine operation. Second, the increased water concentration in the exhaust created difficulties in the exhaust system and was suspected to have produced a water emulsion in the oil.

An Experimental Study on Fuel Economy Improvement of a Marine Diesel Engine Using a Sequential Turbocharging System

2018 ◽  
Author(s):  
Hechun Wang ◽  
Xiannan Li ◽  
Yinyan Wang ◽  
Hailin Li
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Engine Speed ◽  
Single Stage ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Engine Operation ◽  
Marine Diesel ◽  
High Torque

Marine diesel engines usually operate on a highly boosted intake pressure. The reciprocating feature of diesel engines and the continuous flow operation characteristics of the turbocharger (TC) make the matching between the turbocharger and diesel engine very challenging. Sequential turbocharging (STC) technology is recognized as an effective approach in improving the fuel economy and exhaust emissions especially at low speed and high torque when a single stage turbocharger is not able to boost the intake air to the pressure needed. The application of STC technology also extends engine operation toward a wider range than that using a single-stage turbocharger. This research experimentally investigated the potential of a STC system in improving the performance of a TBD234V12 model marine diesel engine originally designed to operate on a single-stage turbocharger. The STC system examined consisted of a small (S) turbocharger and a large (L) turbocharger which were installed in parallel. Such a system can operate on three boosting modes noted as 1TC-S, 1TC-L and 2TC. A rule-based control algorithm was developed to smoothly switch the STC operation mode using engine speed and load as references. The potential of the STC system in improving the performance of this engine was experimentally examined over a wide range of engine speed and load. When operated at the standard propeller propulsion cycle, the application of the STC system reduced the brake specific fuel consumption (BSFC) by 3.12% averagely. The average of the exhaust temperature before turbine was decreased by 50°C. The soot and oxides of nitrogen (NOx) emissions were reduced respectively. The examination of the engine performance over an entire engine speed and torque range demonstrated the super performance of the STC system in extending the engine operation toward the high torque at low speed (900 to 1200 RPM) while further improving the fuel economy as expected. The engine maximum torque at 900 rpm was increased from 1680Nm to 2361 Nm (40.5%). The average BSFC over entire working area was improved by 7.4%. The BSFC at low load and high torque was significantly decreased. The application of the STC system also decreased the average NOx emissions by 31.5% when examined on the propeller propulsion cycle.

NOx Reduction by Air-Side vs. Fuel-Side Dilution in Hydrogen Diffusion Flame Combustors

2009 ◽  
Author(s):  
Nathan T. Weiland ◽  
Peter A. Strakey
Keyword(s):  
Residence Time ◽  
Diffusion Flame ◽  
Nox Reduction ◽  
Flame Temperature ◽  
Air Entrainment ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Residence Times ◽  
High Hydrogen ◽  
Separation Unit

Lean-Direct-Injection (LDI) combustion is being considered at NETL as a means to attain low NOx emissions in a high-hydrogen gas turbine combustor. Integrated Gasification Combined Cycle (IGCC) plant designs can create a high-hydrogen fuel using a water-gas shift reactor and subsequent CO2 separation. The IGCC’s air separation unit produces a volume of N2 roughly equivalent to the volume of H2 in the gasifier product stream, which can be used to help reduce peak flame temperatures and NOx in the diffusion flame combustor. Placement of this diluent in either the air or fuel streams is a matter of practical importance, and has not been studied to date for LDI combustion. The current work discusses how diluent placement affects diffusion flame temperatures, residence times, and stability limits, and their resulting effects on NOx emissions. From a peak flame temperature perspective, greater NOx reduction should be attainable with fuel dilution rather than air or independent dilution in any diffusion flame combustor with excess combustion air, due to the complete utilization of the diluent as a heat sink at the flame front, although the importance of this mechanism is shown to diminish as flow conditions approach stoichiometric proportions. For simple LDI combustor designs, residence time scaling relationships yield a lower NOx production potential for fuel-side dilution due to its smaller flame size, whereas air-dilution yields a larger air entrainment requirement and a subsequently larger flame, with longer residence times and higher thermal NOx generation. For more complex staged-air LDI combustor designs, dilution of the primary combustion air at fuel-rich conditions can result in full utilization of the diluent for reducing the peak flame temperature, while also controlling flame volume and residence time for NOx reduction purposes. However, differential diffusion of hydrogen out of a diluted hydrogen/nitrogen fuel jet can create regions of higher hydrogen content in the immediate vicinity of the fuel injection point than can be attained with dilution of the air stream, leading to increased flame stability. By this mechanism, fuel-side dilution extends the operating envelope to areas with higher velocities in the experimental configurations tested, where faster mixing rates further reduce flame residence times and NOx emissions. Strategies for accurate CFD modeling of LDI combustors’ stability characteristics are also discussed.

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