Nitrogen Oxides In Exhaust Gas Research Articles

Impact of Biofuel on the Environmental and Economic Performance of Marine Diesel Engines

The results of the research work on biofuel’s impact on the environmental and economic performance of marine diesel engines are presented. During the research, a fuel mixture was used that consisted of the diesel fuel RMA10 and FAME biofuel. The objective of the research was to determine the optimal concentration of biofuel mixed with diesel fuel. The research work was carried out on three of the same type of marine medium-speed diesel engine, 6N165LW Yanmar. One of the diesel engines only operated on diesel fuel, and the other two operated on a mixture of diesel fuel and 5–20% biofuel. During the experiment, the diesel engines operated at a load of 50–80% of the rated value. Experimentally, it was found that using biofuel improved the environmental friendliness of diesel engines: the emission of nitrogen oxides in exhaust gases was reduced by 8.7–23.4%, and the emission of carbon oxides in exhaust gases was reduced by 3.1–24%. However, when using biofuel, the economic efficiency of diesel operation decreased as the specific effective fuel consumption increased by 0.5–9.3%. The highest environmental efficiency was achieved when using a fuel mixture that included 10–15% biofuel in an 80% diesel load. In this case, the emission of nitrogen oxides was reduced by 21–23.5%, the emission of carbon oxides was reduced by 16.5–19.2%, and the magnification of the specific useful consumption of the diesel engine was 1–1.55%.

Ensuring Reliable and Safe Operation of Trunk Diesel Engines of Marine Transport Vessels

In this study, a method for ensuring reliable and safe operation of marine trunk diesel engines is considered. The research was carried out on 5L23/30 MAN-B&W diesel engines of a Bulk Carrier class vessel. The objective of the study was to determine the effect of the structural characteristics of the oil layer (wetting angle and thickness) on the operational parameters of a marine diesel engine (compression pressure, concentration of nitrogen oxides in exhaust gases and temperature of exhaust gases after the cylinder) and performance characteristics of the oil (base number, wear and contaminant elements). It has been established that an increase in the degree of the contact angles of wetting and in the thickness of the oil layer improves the heat and power and environmental performance of a diesel engine. At the same time, the decrease in compression pressure in the cylinder slows down, the temperature of gases after the cylinder decreases, and the emission of nitrogen oxides with exhaust gases decreases. Also, it was found that wear of diesel parts and oil oxidation are reduced. The study confirms the possibility of improving the reliable and safe operation of trunk-type diesel engines of maritime vessels by effective control of variables relating to the characteristics of engine oil.

Расчетное исследование рабочего процесса двухтопливного водородного двигателя

from alternative raw materials. Hydrogen is considered as a promising alternative fuel. Using the Diesel-RK software package, computational studies of the effect of hydrogen supply on the workflow of a D-245 gas-diesel engine were carried out. The diesel cycle of the engine and its gas-diesel cycle with hydrogen supplies equal to 5, 10, 20, 40, 60 and 80 % are calculated (taking into account the difference in the heat of combustion of diesel fuel and hydrogen). The maximum equivalent efficiency of the diesel engine is achieved when 40 % hydrogen is supplied to the combustion chamber. In this case, compared to working only on petroleum diesel fuel, the effective efficiency of diesel increased by 6.7 %. The transition of diesel engines from petroleum diesel fuel to work with the addition of hydrogen in an amount of 40 % is accompanied by a decrease in the specific emission of carbon dioxide by 44 %, the smokiness of exhaust gases by 53 %. However, an increase in the content of nitrogen oxides in exhaust gases by 27 % was noted.

Finding the Optimal Fatty Acid Composition for Biodiesel Improving the Emissions of a One-Cylinder Diesel Generator

Nitrogen oxides (NOx) and particulate matter (PM) currently are the main pollutants emitted by diesel engines. While there is a start in using hybrid and electric cars, ships will still be fueled by mineral oil products. In the quest to achieve zero-pollution and carbon-free shipping, alternative forms of energy carriers must be found to replace the commonly used mineral oil products. One of the possible alternative fuels is biodiesel. This paper explores the optimization of the composition of biodiesel in order to reduce the concentration of particulate matter and NOx in exhaust gases of a one-cylinder diesel generator.

APPLYING OF FUEL ADDITIVES IN MARINE DIESEL ENGINES

A method for improving the operational characteristics of a marine diesel engine by applying fuel additives has been proposed. A marine medium-speed four-stroke cycle diesel 6L20 by Wartsila-Sulzer was used for this research. It was shown that the use of fuel additives improves fuel efficiency of a marine diesel, in particular reduces specific fuel oil consumption by 3.5 to 5.8 % subject to diesel load and additive concentration in the fuel. Improved environmental performance of the diesel – decrease by 1.4 … 4.3 % in the concentration of nitrogen oxides in exhaust gases, was also found. It was shown that the concentration of the additive has an optimal value, can be determined experimentally and depends on the characteristics of the fuel and the load on the diesel engine.

Oxide Emissions Reduction from Combustion Control in a Diesel Engine

The authors showed that the European Union norms for the toxicity of exhaust gases (Euro 1 – Euro 5) contributed to the reduction of main harmful components emissions by several times. In foreign countries, Stage and Tier regulations applied to tractor equipment, which also limited the content of toxic components at the legislative level.(Research purpose) To reduce the content of nitrogen oxides in exhaust gases by more efficient regulation of the fuel charge distribution in the gas-diesel engine cylinder, changes in the concentration of diesel and gas fuel in certain zones, as well as the use of exhaust gas recirculation.(Materials and methods) The authors analyzed the results of modeling the formation of nitrogen oxides by controlling the workflow in the gas-diesel modification of the diesel engine. In the calculations, the geometric parameters of the D-120 engine, operating at 2000 revolutions per minute, with a filling of 0.6-0.9 volume, were used. The average excess air ratio for the charge was 1.2-3.0, and the excess air ratios for the gas-air mixtures did not exceed 1.2-2.5.(Results and discussion) Using the computational model, the authors estimated the parameters at different pressures at the engine inlet within 0.05-0.09 megapascals, as well as with an increase in the residual gas coefficient in the range of 5-15 percent with a decrease in the concentration of nitrogen oxides from 2500 to 1100 parts per million. Experiments showed that when the power changed from 100 to 20 percent, the nitrogen oxides concentration decreased from 1940 to 800 parts per million.(Conclusions) The authors confirmed the adequacy of the calculation model. They determined that a 40-50 percent reduction in the nitrogen oxide concentration in exhaust gases was achieved with various layering schemes in the combustion chamber. They found that the standards for carbon monoxide, hydrocarbons and nitrogen oxides would require mixed engine regulation. It was proved that recirculation of 15 percent of exhaust gases could reduce nitrogen oxide emissions by another 50 percent. 

The effect of methyl hydroxide ignition in CI motor on the volumetric upkeep of nitrogen oxides in exhaust gases

This article presents the results of the education of output values of the volumetric upkeep of NOx in the EG. There are three ways of education of NOx, differing in the method of origin. The education of NOx can occur in the flame front, in which clusters of atomic oxygen and hydroxyl radical are observed, which are several orders of magnitude higher than the equilibrium ones in the zone of ignition products. The calculated data on the education of NOx in the CI motor cylinder by two reactions of the chain mechanism and the reaction of the bimolecular mechanism by equilibrium clusters in the zone of ignition products are in good agreement with the experimental ones.

Modernization of a tractor motor for diesel combustible and methanol

When carrying out research to improve the environmental performance of motors, attention should be paid to reducing the nitrogen oxide content of the effluent gases, since they are the most toxic components among the entire range of polluting chemical compounds contained in exhaust gases, since they are formed in the burning process as a result of chemical reactions atmospheric oxygen and nitrogen. The most effective way of using methanol in internal burning engines is now to feed it directly to the diesel cylinder using a dual combustible supply system, which allows replacing up to 80% of the diesel combustible. The ignition of methanol in this case is due to the supply of a seed portion of diesel combustible. This method, with some changes and additions to the design of the motor, can be implemented on engines already in operation. In this paper, the effect of methanol application on the volumetric content and mass concentration of nitrogen oxides in exhaust gases calculated on the basis of the results of experimental studies of a motor of 2H 10.5 / 12.0 air cooling with a hemispherical burning chamber in a piston using a dual combustible delivery system and injection of diesel combustible (ignition) through a multi-jet nozzle, depending on the change in load.

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It is expected that since 2021, at the initiative of the International Maritime organization, the control zones for nitrogen oxide emissions in the exhaust gases of ship power plants will be expanded to cover the regions of the Baltic and North Seas. In such circumstances, shipowners operating in these regions, at the stages of modernization and construction of new ships inevitably face the problem of choosing a way to meet the new requirements. The following variants of compliance are considered: selective catalytic reduction of nitrogen oxides; application of exhaust gas recirculation system; use of alternative fuels, as well as a number of technical solutions related to the direct impact on the working process of the engine, aimed at reducing the emission of nitrogen oxides. It is noted that the consideration of various technologies to meet the new requirements and analysis of their advantages and disadvantages will create prerequisites for the choice of the concept and the way to achieve the requirements of the environmental standard TIER III, used in emission control zones. Attention is drawn to the fact that in order to achieve the requirements of the TIER III standard, first of all, the systems of selective catalytic recovery and exhaust gas recirculation are considered as the most proven technologies. In conclusion, it is noted that ensuring the environmental requirements of the TIER III standard for a wide range of operating modes of the ship’s power plant is a complex task, the solution of which can be achieved during the engine design by the simultaneous implementation of various technologies to reduce NOx emissions. The increased demand for TIER III engines can be expected to provide additional motivation for manufacturers to find and implement new design solutions aimed at reducing the content of nitrogen oxides in exhaust gases, as well as to refine and make more extensive use of already known methods to combat NOx emissions.

INCREASE OF ECOLOGICAL EFFECTIVENESS OF COMPLEX HEAT-RECOVERY SYSTEMS FOR BOILER PLANTS

It is revealed that the humidifying of blown air in complex heat recovery systems of gas-fired boiler plants provides the significant reduction in the concentration of nitrogen oxides in exhaust-gases due to the suppression of their formation in the boiler furnace when moisture is introduced with this air. 
 Problems of environmental protection and energy-saving became priority in world practice. The main directions of deciding these pressing problems in municipal heat-power engineering is to improve the environmental indicators of heating boiler plants and increase the efficiency of using fuel in them through the use of technologies for deep recovery of the exhaust-gases heat. The relevance of scientific problems in these directions is increasing due to the steady increase in the fuel-energy costs and the strengthening of requirements to reducing environmental pollution.
 When using these technologies of deep heat-recovery of exhaust-gases, the condensation mode of the heat-recovery equipment is realized, when, apart from to the so-called clear heat of these gases, the latent heat of condensation of the water vapor contained in them is also used. The condensation mode implementation also improves the ecological indicators of the boiler due to the reduction of fuel consumption and the dissolution in the resulting condensate of a part of harmful emissions formed during its combustion.
 The use of modern heat-recovery technologies for the gasfired boiler plants with complex use of recovered heat for the preheating of boiler water, water of the chemical waterpurification system and blowing air makes it possible to reduce fuel consumption in the boiler and, accordingly, its harmful emissions by 8...12 %.
 Humidification of the blowing air through the use of the recovery heat also provides a reduction of nitrogen oxides emissions to 60 % by suppressing their formation in the boiler combustion chamber.

Research into emissions of nitrogen oxides when converting the diesel engines to alternative fuels

We conducted theoretical and experimental research into emissions of nitrogen oxides in exhaust gases of the diesel engines, re-equipped for gas. The research is important because the emissions of nitrogen oxides in the exhaust gases are one of the biggest environmental problems at the present stage of development of designs for internal combustion engines. Therefore, reducing the emissions of nitrogen oxides in diesel engines by re-equipping them to gas fuel is an important task for specialists in design and operation of internal combustion engines. The result of theoretical research is the mathematical model that we constructed in order to calculate emissions of nitrogen oxides in the exhaust gases of diesel engines and the engines, converted to gas fuel. Based on experimental research, we have established dependences of emissions of nitrogen oxides in exhaust gases of the diesel engines, re-equipped for gas, on loading and the crankshaft rotation frequency. Studies have shown that diesel engines, which are converted to alternative gas fuel, reduce emissions of nitrogen oxides in the exhaust gases in a range from 13.9 % to 47.1 % depending on engine rotation and load. The results obtained make it possible to reduce the emissions of harmful substances in exhaust gases of automobile engines and optimize design of the systems for exhaust gases recirculation

The influence of non-cooled exhaust gas recirculation on the indicator diagrams and heat release parameters in diesel engine cylinder

This paper presents the results of the diesel engine research on the indicator and heat realized diagrams for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurement was carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine load. Some of the analyzed parameters were read directly from the measurement systems (e.g. indicator diagrams) or engine controller (e.g. start of injection) and the rest of them had to be calculated. The calculation of rate of heat release (dQ/dα) was based on the well-known mathematical model. When the exhaust gas recirculation valve is open, the maximum of combustion pressure and rate of maximum kinetic heat release (dQk/dα)max are smaller than when the valve is closed. These facts are connected with the shorter self-combustion delay for engine working with EGR. But this is also associated with reduction of the rate of maximum diffusion heat release (dQd/dα)max, which means that more particulates (PM) are excreted into the atmosphere. This fact explains e.g. significantly higher smog of exhaust gases for diesel engine which works with EGR system. The analysis results show that exhaust gas recirculation system slightly deteriorates the energetic parameters of VW 1.9 TDI engine, but, at the same time, significantly reduces the level of toxic nitrogen oxides in exhaust gases

Emission reduction methods and split fuel injection in a marine four-stroke engine

The new emission legislation for sea-going vessels issued by the International Maritime Organization (IMO) requires drastic reduction in exhaust gas nitrogen oxides (NOx), and the combination of different primary methods can be an interesting solution without increasing remarkably the machinery. In this paper, the Miller cycle and the dilution with exhaust gas in the combustion chamber were tested to reach the Tier III limits for a four-stroke marine engine. In particular, the Miller cycle is used to reduce the in-cylinder temperature, and lower oxygen content in the combustion chamber is realized with cooled exhaust gas recirculation (EGR). Despite a remarkable reduction in NOx, the main drawback was a significant increase in fuel consumption. Split injection is combined with the abovementioned methods, in order to improve the engine efficiency. The novelty of this study consists in the simultaneous use of a split fuel injection, the Miller cycle and EGR in a marine-size application. Along this study, combining Miller timing with a relatively low EGR rate reduces NOx emissions by 90%. On the other hand, split injection does not bring significant advantages in fuel economy, although the results with very early pilot injection suggest further studies to be realized.

Structures of Bimetallic Copper–Ruthenium Nanoparticles: Incoherent Interface and Surface Active Sites for Catalytic Nitric Oxide Dissociation

Bimetallic alloy nanoparticles are promising candidates for replacing platinum group metals utilized in the catalytic removal of nitrogen oxides in exhaust gas. In this study, we investigated the electronic, interfacial, and surface structures of copper/ruthenium alloy nanoparticles by quantum chemical computations using 135-atomic cluster models. We employed Ru-core/Cu-shell models in which the Ru-core takes both fcc (face-centered cubic) and hcp (hexagonal closed-packed) structures. The fcc-core model has a coherent Cu/Ru interface, while the hcp-core model involves an incoherent interface. This incoherence results in discontinuity in the lattice structure and the valence electronic structure, and generates step-like structures on the surface of the particle. Such a step-like site enhances the catalytic activities for nitric oxide dissociation. The orbital energies suggest that the alloying can control the oxidation tendency of clusters. Charge-transfer occurs between the Cu shell and Ru core; the surfa...

An improved method for selective catalytic reduction of nitrogen oxides in exhaust gases

The selective catalytic reduction (SCR) of nitrogen dioxide in an air flow modeling the exhaust gas from an internal combustion engine is studied. Granulated V2O5 (13.5%)–MnO2 (0.7–1.0%)/Al2O3 powder (AVK-10M catalyst) and ammonia injected into a SCR catalytic cell are used as a heterogeneous catalyst of NO2 reduction and a reducing agent, respectively. If the efficiency of NO2 removal is high enough and satisfies the requirements of the State Sanitary Standards for the maximum permissible concentrations of substances emitted into the atmosphere ( $$MP{C_{N{O_2}}}$$ = 0.085 mg/m3), the reducing agent (ammonia) is not completely consumed during SCR, so a considerable amount of NH3 can be released into the atmosphere. Therefore, a strict control of both NO2 and unreacted ammonia emissions is needed. The dependences of the concentrations of [NH3] and [NO2] on the [NH3]/[NO2] ratio for the model air flow passed through the AVK-10M granular heterogeneous catalyst are measured. It is found that the maximum degree of removal of NO2 from the air takes place at [NH3]/[NO2] = 1.3. In the conventional process, the concentration of [NO2] drop from 530.00 to 0.07 mg/m3, i.e., below the $$MP{C_{N{O_2}}}$$ . At the same time, the ammonia concentration increases to [NH3] = 3.4 mg/m3, which becomes 85 times the $$MP{C_{N{O_2}}}$$ , 0.04 mg/m3. To remove unreacted ammonia from air flows, we developed [P–(SO3 -)2 · Me2+] sulfocationites, where Me are the Cu and/or Ca ions, P is a styrene–divinylbenzene copolymer. It is shown that the concentration of ammonia passed through the adsorption cell filled with a freshly sulfocationite drops below $$MP{C_{N{H_3}}}$$ = 0.04 mg/m3. The dependences of the dynamic exchange capacity (DEC) before ammonia breakthrough for the [P–(SO3 -)2 · Cu2+] delta-sulfocationite on the air flow rate, [NH3] concentration, and humidity are measured. The maximum value of the DEC, δ = 59.5 mg/cm3, is observed at an air flow velocity of 2.171 m/s, [NH3] = 0.0035 mg/L, and 75% humidity. To illustrate practical applications of the proposed improved SCR method, it is shown that a 3-L replaceable [P–(SO3 -)2 · Cu2+] sorbent cartridge in a SCR exhaust gas purifier for a car internal combustion engine does not need replacement more frequently than every 50000 km.

An overview of systems supplying water into the combustion chamber of diesel engines to decrease the amount of nitrogen oxides in exhaust gas

The paper analyses legal requirements for the composition of exhaust gas emitted by ships, marine engines including. The background for this paper is the increasingly stricter limits set for the emission of the toxic exhaust gas components by marine engines. Legal requirements force designers to search for new constructions of marine propulsion systems and constantly improve the existing ones. One of the solutions is supplying water into the combustion chambers of diesel engines—the solution widely known for many years n ow wins favour and, according to the authors, has a chance to gain competitive advantage over alternative constructions. A special attention has been paid to the allowed amount of nitrogen oxides and sulphur oxides in exhaust gas resulting from the International Convention for the Prevention of Pollution from Ships. So far, one, global evaluation of brand new and retrofitted marine propulsion system designs presenting this issue thoroughly has not been done. The authors’ interest in the issue derives from this fact and has been confirmed by many papers. We showed the mechanism of decreasing nitrogen oxides in exhaust gas by means of water supply into the combustion chambers of diesel engines. We presented an overview of designs which might be used to retrofit vessels already in operation or introduced at the stage of vessel construction in the shipyard. The paper also contains an evaluation of the described designs. The following systems have been discussed: continuous water injection into the scavenging air, humid air motor, direct water injection with the use of combined nozzles, water-cooled residual gas system and fuel–water emulsion supply system using emulsifiers or devices of high-pressure water injection into fuel. We have made a comparison of the effectiveness of different methods used to reduce the emission of nitrogen oxides. Advantages and disadvantages of supplying water into the combustion chambers of diesel engines have been shown together with the comparison of the range of changes in their construction. The authors have indicated potential opportunities derived from injecting Brown’s gas into the combustion chamber in order to change the composition of the exhaust gas. As a consequence, it will also affect the natural environment where vessels operate.

Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

Abstract This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode, i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol. Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets, bio-ethanol production methods and dynamics of its production worldwide and in Poland. Te considerations are illustrated by results of the tests on spark- ignition and self- ignition engines fed with two fuels: petrol and methanol or diesel oil and methanol, respectively. Te tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. Te other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. Te tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters (maximum power and torque). In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI (petrol) engine, and 2-3 fold lower smokiness in case of ZS (diesel) engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx - for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.

D213 NOx吸蔵触媒を用いた排気中の窒素酸化物の選択的吸収・再生(OS5 バイオマス・新燃料・環境技術(1))

D213 NOx吸蔵触媒を用いた排気中の窒素酸化物の選択的吸収・再生(OS5 バイオマス・新燃料・環境技術(1))

Investigation of selective catalytic reduction for control of nitrogen oxides in full-scale dairy energy production

Selective catalytic reduction (SCR) was used to reduce exhaust gas nitrogen oxides (NOx) from the emissions of a 710kW combined heat and power system fueled by dairy biogas. Exhaust gas NOx was reduced from 63.1±31.9 to 14.2±17.5ppmvd@15% O2 such that emissions were 0.33±0.40gkW−1h−1, based on data averaged over 15min intervals. Online exhaust gas sensors with integrated process control algorithms were effective in improving NOx removal by automated control of urea, the ammonia source used for catalysis of NOx reduction reactions. Pre-SCR NOx was most strongly correlated with equivalence ratio (R2=0.39), indicative of the air–fuel ratio. A concave relationship between NOx production and thermal conversion efficiency was not observed since lean-burn operation of the engine was consistent and only altered under low engine load. Following installation of pre- and post-SCR NOx sensors, average daily exhaust gas NOx reduction in the SCR was 82.6±8.5%. Post-SCR NOx emissions were typically impacted by pre-SCR NOx (R2=0.36), suggesting that altered operation of the anaerobic digesters or modifications to the engine would be effective in reducing NOx emissions as well as urea demand. After nearly three years of operation, the SCR catalyst remains in service without requiring replacement. Average daily urea demand was 31.8±16.3Ld−1 for the system that produced 369±136kW of electricity. During the second year of observation the regulatory limit of 0.804gkW−1h−1 was met 94% of the time while the regulatory target of 0.201gkW−1h−1 was only met 45% of the time, based on data averaged over 15min intervals. These results provide guidance for dairy energy projects in locations with stringent NOx emissions standards.

Verification of the concept of spray mechanism assisted with air dissolved in diesel oil

In reference to the paper “The application of gas dissolved in fuel with a view to improve the mechanism of spraying“ [1], this article continues with the issue of spray mechanism improvements. It includes the results of tests with a one-cylinder CI engine powered with a solution of diesel oil and air. The proposed changes in the spray mechanism were evaluated contrastively. The analysis encompasses: indicator pressure in the cylinder as well as the maximum value of pressure increase rate, self-ignition delay angle, the time span of combustion, the content of carbon oxide, hydrocarbons, nitrogen oxides in exhaust gas, as well as the degree of exhaust gas blackening. Some positive changes in the combustion process, induced by the improvements in spray mechanism, have been shown.