Diesel Exhaust Gas Research Articles

“NaClO2-Sea Water” Wet Denitrification Technology Using NOx Treatment Technology in the Desulfurization and Denitrification of Ship Exhaust Gas

To minimize the emission pollution of nitrogen oxides (NOx) in marine diesel engine exhaust, based on the existing NOx treatment technology, the "NaClO2-sea water" wet denitrification technology was further proposed. The denitrification performance of NaClO2 solution in seawater and NaClO2 solution in fresh water was analyzed by self-designed and built experimental platform. Moreover, the effects of the temperature of the absorption solution, the initial concentration of NaClO2 and the concentration of NO in diesel exhaust gas on the denitrification performance of NaClO2 sea water solution were studied. The experimental results showed that the denitrification rate of NaClO2 solution with seawater as solvent was slightly lower than that of NaClO2 solution with fresh water, but the denitrification duration of seawater solution had obvious advantages over that of fresh water solution. In addition, by increasing the temperature of the absorption solution and the initial concentration of NaClO2 and decreasing the concentration of NO, the denitrification rate of NaClO2 sea water solution was increased. Whereas, if the temperature exceeded a certain limit, the continuous denitrification time of the solution would be decreased. Therefore, “NaClO2-sea water” wet denitrification technology has the advantages of cheap raw materials and long continuous denitrification time. High denitrification efficiency can be achieved by optimizing reaction conditions, so it can be used for denitrification of marine diesel engine exhaust gas.

Integrated diesel engine toxicity reduction system

The issues of natural gas application and recirculation as a complex method of reducing the toxicity of diesel exhaust gases are considered. The results of experimental studies on the influence of natural gas and recirculation on the effective characteristics, toxicity and smokiness of exhaust gases are presented. At the same time, special attention is paid to power and economic characteristics, indicators of the combustion process, toxicity and smokiness of exhaust gases. The presented results of experimental studies prove the effectiveness of the application as a comprehensive system of reducing the toxicity of diesel engine natural gas and exhaust gas recirculation.

ИСПОЛЬЗОВАНИЕ СОИ СЕВЕРНОГО ЭКОТИПА НА БИОТОПЛИВО

The paper presents the results of long-term research on the oil productivity and chemical composition of soybean oil of the Northern ecotype varieties in the Central Non-Black Earth Region. The authors consider its possible use for biodiesel production. Experiments on growing soybeans were carried out on the experimental fi eld of Russian State Agrarian University –Moscow Timiryazev Agricultural Academy (2008-2019) on recognized ultra-early ripening varieties of the Northern ecotype Mageva, Svetlaya, Okskaya (ripeness group 000). Tests were set and the research results were analyzed using standard approved methods. It has been shown that in conditions of high latitudes (57°N), limited thermal resources of the Non-Chernozem zone of Russia (the sum of active temperatures of the growing season not exceeding 2000°С), the yield and productivity of soybeans depend on the variety and moisture supply. Over the years, the average yield of soybeans amounted to 1.94 … 2.62 t/ha, oil productivity – 388 … 544 kg/ha, oil content – 19…20%, the content of oleic and linoleic fatty acids in oil – 60%, and their output from seeds harvested – 300 kg/ha. It has been established that as soybean oil and diesel fuel have similar properties,they can be mixed by conventional methods in any proportions and form stable blends that can be stored for a long time. Experimental studies on the use of soybean oil for biodiesel production were carried out on a D-245 diesel engine (4 ChN11/12.5). The concentrations of toxic components (CO, CHx, and NOx) in the diesel exhaust gases were determined using the SAE-7532 gas analyzer. The smoke content of the exhaust gases was measured with an MK-3 Hartridge opacimeter. It has been experimentally established that the transfer of a diesel engine from diesel fuel to a blend of 80% diesel fuel and 20% lubrication oil leads to a change in the integral emissions per test cycle: nitrogen oxides in 0.81 times, carbon monoxide in 0.89 times and unburned hydrocarbons in 0.91 times, i.e. when biodiesel as used as a motor fuel in a serial diesel engine, emissions of all gaseous toxic components are reduced. The study has confi rmed the expediency of using soybeans of the Northern ecotype for biofuel production.

Holistic Control of Diesel Engines and Exhaust Gas Aftertreatment

Holistic Control of Diesel Engines and Exhaust Gas Aftertreatment

Urea derived deposits in diesel exhaust gas after-treatment: Integration of urea decomposition kinetics into a CFD simulation

Formation of solid urea by-products in mixing sections of SCR systems is a well-known problem in development and design of exhaust gas after treatment systems. Spray impingement induces liquid film formation on mixer blades and tailpipe walls, from which urea by-products can be derived in dependence on temperature and residence time. This work presents a comprehensive modeling approach for prediction of by-product formation. An existing kinetic model for urea decomposition is integrated into CFD simulations by user coding. Implementation is evaluated by 3D simulations of thermogravimetric decomposition of urea and its by-products. Results are compared to experimental data and simulation results from a 0D model. Furthermore, the procedure is applied to simulations of a flow setup including urea injection for demonstration of the model capabilities.

Precise evaluation the effect of microwave irradiation on the properties of palm kernel oil biodiesel used in a diesel engine

Abstract Palm kernel oil (PKO) has an appropriate oil content which can be utilized for biodiesel production. Sparse studies have been performed on its ability as well as the produced biodiesel properties and performance in the diesel engine. Further, no study has been performed on the conversion of PKO via microwave irradiation and comparing the PKO biodiesel abilities combusted in diesel engines with those prepared by conventional methods. For this purpose, PKO was directly extracted from date palm fruits (Phoenix dactylifera) with microwave and conventional heating systems utilized for conversion of PKO to biodiesel. In addition to optimization of microwave-assisted transesterification reaction conditions, variations of temperature during each run were carefully monitored. The results revealed that palm kernel has 10 wt% of oil containing high unsaturated fatty acids and free fatty acid (FFA). The transesterification reaction was sharply accelerated by microwave power such that the reaction time diminished from 90 min for conventional method to 2.5 min. The results of temperature monitoring confirmed great elevation in the reaction temperature (over boiling point of methanol) with the rise of microwave power and methanol/oil ratio. Moreover, reduction of temperature occurred with more loading of catalyst due to greater formation of soap. Both high and low temperatures showed negative effects on the yield of transesterification reaction. The performance and emissions gas evaluation of the engine fueled by PKO biodiesel produced by microwave and conventional heating system indicated that the fuel produced by microwave irradiation can sharply reduce the CO and HC and insignificantly increase NOx in exhaust emission as compared to fuel produced by the conventional method. Also, higher amounts of microwave-assisted produced PKO biodiesel can be blended with net diesel fuel to use in diesel engines. The results suggested that microwave irradiation can considerably influence the phytochemical properties of biodiesel and improve its combustion profile in the diesel engine and exhaust gas emissions.

Study Influences the Jatropha-Diesel Mixing Ratio to the Formation of Soot Emissions in Diesel Exhaust Gases

To cope with the depletion of fossil fuels and the threat of exhaust pollution from internal combustion engines, research finds alternative fuels. Step by step to completely replace fossil fuels that will be exhausted in the future and environmentally friendly due to internal combustion engines is an urgent and important issue. Diversify fuel sources used for internal combustion engines and environmentally friendly when using Jatropha - Diesel fuel mixture. The paper focuses on studying the ability to use biodiesel derived from Jatropha seeds with the volume ratios of 5%, 10% and 15% on experimental engines. Thereby, it will analyze and evaluate the technical features and pollution levels of engines compared to pure fuels. Experimental study assessing the effect of Jatropha - Diesel mixing ratio on the emission formation compared with emissions in Vikyno EV2600 engines.

The Study Influences the Jatropha-Diesel Mixing Ratio to the Formation of Soot Emissions in Diesel Exhaust Gases

To cope with the depletion of fossil fuels and the threat of exhaust pollution from internal combustion engines, research finds alternative fuels. Step by step to completely replace fossil fuels that will be exhausted in the future and environmentally friendly due to internal combustion engines is an urgent and important issue. Diversify fuel sources used for internal combustion engines and environmentally friendly when using Jatropha - Diesel fuel mixture. The paper focuses on studying the ability to use biodiesel derived from Jatropha seeds with the volume ratios of 5%, 10% and 15% on experimental engines. Thereby, it will analyze and evaluate the technical features and pollution levels of engines compared to pure fuels. Experimental study assessing the effect of Jatropha - Diesel mixing ratio on the emission formation compared with emissions in Vikyno EV2600 engines.

Selective catalytic reduction of NO at low temperature using a (ethanol+ammonia) mixture over a Ag/Al2O3 + WO3/Cex-ZryO2 dual-bed catalytic system: Reactivity insight of WO3/Cex-ZryO2

The Selective Catalytic Reduction (SCR) is one of the most efficient process for NOx removal from Diesel exhaust gas. However, the urea/NH3-SCR process implemented in recent vehicles still suffers from a poor activity in the low temperature range (T < 250°C). One main reason is its dependency against the NO2/NOx ratio, limiting the expected fast-SCR reaction in this temperature range. Recently, we shown that the addition of ethanol to ammonia led to a significant increase of the activity of a Ag/Al2O3 catalyst in this low temperature range. Moreover, in a dual-bed configuration (Ag/Al2O3+WO3/Cex-ZryO2), a remarkable improvement was achieved at low temperature using only NO as NOx. The present work aims to highlight the DeNOx chemistry encountered over the WO3/Cex-ZryO2 catalyst in a bifunctional (EtOH+NH3) mixture. In addition to the fact that this process takes advantage of the low temperature NO2 formation over the upstream Ag/Al2O3 catalyst, this work also puts in evidenced unexpected interactions between NO2 and CH3CHO (resulting from ethanol oxidation over Ag/Al2O3) thus leading to NO emission.

Pt–Pd/MnOx–Al2O3 Oxidation Catalysts: Prospects of Application for Control of the Soot Emission with Diesel Exhaust Gases

Together with exhaust gases from motor vehicles with diesel engines, soot and toxic nitrogen oxides are released into the environment. In this work, we consider the possibility of removing diesel soot on the surface of the Pt–Pd/MnOx–Al2O3 oxidation catalyst with a low Pt–Pd content. The rate and activation energy of the catalytic oxidation of diesel soot with oxygen and NOx were studied in the isothermal mode and compared with the kinetic characteristics of the oxidation of charcoal soot and two samples of synthetic soot (Printex U, Vulkan XC-72). The physicochemical properties of soot, such as nano- and microstructure, elemental composition, composition of surface functional groups, determine its oxidative reactivity, which is higher in mixtures with NOx than in oxygen-containing mixtures.

Changes of Mouse Alveolar Epithelial Cells by Diesel Exhaust Gas Inhalation Exposure in Electron Micrograph

Changes of Mouse Alveolar Epithelial Cells by Diesel Exhaust Gas Inhalation Exposure in Electron Micrograph

Thermal performance of a rectangular exhaust gas recirculation cooler subject to hydrocarbon and water vapor condensation

The reliability of exhaust gas recirculation (EGR) coolers, which are commonly used to lower emission of nitrogen oxides (NOx) from diesel-driven engine cars, can profoundly be compromised by deposition of soot particles and hydrocarbon (HC) species on EGR surfaces. This study discerns the impacts of HC and water condensation on deposit formation of a rectangular EGR cooler with surrogate species of soot particles, water and icosane as heavy hydrocarbon. To do so, an experimental test facility was assembled in which a rectangular channel with removable plates was utilized to visualize deposition along with HC and water condensation. Icosane as a hydrocarbon which is common in diesel exhaust gases was injected to the exhaust gas stream during the experiments. The experimental results, under operating conditions attempted in this study, showed that HC condensation could be a dominant factor in diminishing particulate deposition if injected prior to the presence of soot particles, which is of practical implication. The change in coolant temperature from 90 °C to 25 °C also resulted in reduction of fouling resistance of up to 60%. It is thus preferable to maintain the coolant temperature as low as possible during the operation. Furthermore, the condensation of water vapor droplets on the cooler surface can partially result in deposit layer flake-off and consequently mitigate the EGR cooler fouling to some extent.

NO Removal from Simulated Diesel Engine Exhaust Gas by Cyclic Scrubbing Using NaClO2 Solution in a Rotating Packed Bed Reactor

Experiments were conducted to remove NO from simulated flue gas in a rotating packed bed (RPB) reactor with NaClO2 as wet scrubbing oxidant and diesel exhaust gas as carrier gas. The effects of various operating parameters (rotational speed, solution pH, NaClO2 concentration, liquid-gas ratio, and NO and SO2 concentrations) on NO removal performance were investigated preliminarily. The results showed that with the increase of rotational speed, oxidant concentration, and liquid-gas ratio, NO removal efficiency increased obviously. NO removal efficiency increased largely with the decrease of solution pH, and a complete removal of NO could be attained at pH 4. NO concentration imposed little effect on NO removal efficiency while coexisting SO2 in exhaust gas could enhance NOx removal greatly.

Catalytic Properties of Double Substituted Lanthanum Cobaltite Nanostructured Coatings Prepared by Reactive Magnetron Sputtering

Lanthanum perovskites are promising candidates to replace platinum group metal (PGM), especially regarding catalytic oxidation reactions. We have prepared thin catalytic coatings of Sr and Ag doped lanthanum perovskite by using the cathodic co-sputtering magnetron method in reactive condition. Such development of catalytic films may optimize the surface/bulk ratio to save raw materials, since a porous coating can combine a large exchange surface with the gas phase with an extremely low loading. The sputtering deposition process was optimized to generate crystallized and thin perovskites films on alumina substrates. We found that high Ag contents has a strong impact on the morphology of the coatings. High Ag loadings favor the growth of covering films with a porous wire-like morphology showing a good catalytic activity for CO oxidation. The most active composition displays similar catalytic performances than those of a Pt film. In addition, this porous coating is also efficient for CO and NO oxidation in a simulated Diesel exhaust gas mixture, demonstrating the promising catalytic properties of such nanostructured thin sputtered perovskite films.

Оптимизация состава смесевых биотоплив с добавками растительных масел

The paper deals with a topical issue of using biofuels in internal combustion engines. Promising biofuels may be derived from vegetable oils. In agriculture, using blends of petroleum fuel and a moderate amount of vegetable oil is economically feasible. We consider rapeseed oil and sunflower oil as these possible additives. We list physical and chemical properties of vegetable oils and blends of vegetable oils and diesel fuel. We analysed the experimental investigation results concerning the D-245.12S diesel engine running on petroleum fuel and its blends with vegetable oil additives specified above. We demonstrate that it is possible to improve environmental performance of a diesel by using these biofuel blends. We present a method for optimising the composition of petroleum fuel blends with vegetable oil additives that is based on determining a generalised optimality criterion as a sum of partial optimality criteria characterising regulated toxic component content in diesel exhaust gas emissions. We used the method presented to perform optimisation calculations and determine the optimum composition for biofuel blends with vegetable oil additives. We developed a method for estimating environmental safety of diesel power plants that takes into account the concentration of polycyclic aromatic hydrocarbons in the diesel exhaust gases. We show that knowing benzo[a]pyrene emission levels of a diesel running on a specific type of fuel is enough to estimate the degree of environmental threat of its exhaust gases

Titchenko Prospects for the use of dry carbamide in diesel exhaust gas aftertreatment systems

Improvement of diesel exhaust gas aftertreatment systems is one of the most urgent methods of technical competition with the electric transmission, which has been developing rapidly in recent times. The search for the most optimal technical solutions will reduce the environmental load when using diesel engines. This article discusses the prospects for the use of dry carbamide in neutralization systems of diesel engines. A dry carbamide system is free from a significant drawback of the widely used SCR Nitrogen Oxide Reduction System. Such systems are not resistant to low temperatures below -11 °C and require heating, which entails significant energy costs and design complexity. The methods for the direct use of ammonia for the reduction of nitrogen oxides are known. Amminex Company uses ammonia bound in the form of salts. A design that already has practical application is considered. The buses used blocks, generating the required amount of ammonia. One set is enough to work for one two days. Blocks are replaced by infrastructure. The design is simple enough and undoubtedly efficient. There are also patents describing devices based on direct thermolysis of carbomide. In this case, it is possible to create a compact design that requires practical application. The main reactions occurring upon receipt of ammonia from a solution (urea), ammonia salts, and dry carbamide are presented. The features of thermolysis at various heating rates and temperature levels are considered. The paper analyzes the reactions proceeding in three design options. An energy analysis has been carried out and a conclusion has been drawn on the advantage of direct thermolysis of carbamide. A design variant of the exhaust gas aftertreatment system for diesel engines using direct thermolysis is proposed. Based on the results of a wide analysis, it was concluded that the structures constructed on the basis of direct thermolysis of dry solid carbamide are promising.

Effects of Retarding Fuel Injection Timing on Toxic Organic Pollutant Emissions from Diesel Engines

ABSTRACT Retarding the fuel injection timing is an effective strategy for controlling NOx emissions from diesel engines. However, the influence of retarding the fuel injection timing on polycyclic aromatic hydrocarbon (PAH) and persistent organic pollutant (POP) emissions has not yet been investigated. In this study, the diesel engine was tested using four of the existing thirteen European steady state cycle (ESC) modes. The fuel injection timing was retarded from –8° to –6° and the diesel exhaust gas samples were analyzed for PAH and POP emissions. The NOx emission factor reduced by ~25% when the fuel injection timing was retarded. However, the strategy had a negative effect on combustion efficiency. The carbon monoxide (CO) and particulate matter (PM) emissions were 1.4 and 1.2 times higher for the –6° scenario, respectively. The emission factors of all the toxic organic pollutants increased drastically when the fuel injection timing was retarded. For instance, the emission factors of PAH and polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) for the –6° scenario, based on BaPeq and WHO-TEQ, were 22 and 10 times higher than for the –8° scenario. The retardation had more influence on these pollutants in the particle-phase than in gas-phase. The resultant negative impact on combustion increased the emissions of products of incomplete combustion, enhancing the potential of POP formation via de novo synthesis. The study concludes that although retarding the fuel injection timing leads to a decrease in NOx emissions from diesel engines, it also results in an increase in PAH and POP emissions.

Porous permeable metal-ceramic materials on base of iron oxides with addition of the ground complex ores

The self-propagating high-temperature synthesis (SHS) was used to obtain the heat-resistant porous permeable metal-ceramic material (PPMM) on base of the mixture composed of the alloyed steel's scale powder and the oxides of both metals and complex ore (monazite). The prepared SHS-material can be used as the catalytic agent for the diesel's exhaust gas purifcation. However, instead of the expensive rare-earth elements (REE) cerium and thorium the ground complex ores containing these REE can be used. The influence of the monazite's content up to 18 wt. percents on the physical, mechanical and service properties of the prepared materials were regarded in the article.Ill.8. Ref. 17. Tab. 2.

Study of the characteristics of PM and the correlation of soot and smoke opacity on the diesel methanol dual fuel engine

Methanol is regarded as an alternative fuel of diesel for reducing the particulate matter emissions on diesel engines. However, recent studies reveal that methanol has the different effects on particulate matter characteristics at high loads. In order to reduce particulate matter emissions further within the full operating range of the engine, the characteristics of particulate matter and the correlation between soot and smoke opacity were investigated on a turbocharged and intercooled diesel engine under diesel/methanol dual fuel mode. During the experiment, particulate characteristics are primarily exhibited by the characteristics of soot and particulate number. Results show that the engine-out soot and particulate number emissions increase with the increase of methanol substitution percent under high intake temperature at high loads. On the contrary, the engine-out soot and particulate number decrease with the increase of methanol substitution percent under low intake temperature at high loads. There is an applicable scope of methanol substitution percent that effectively reduces soot and particulate number emissions. Methanol substitution percent which is larger than 20% has a significant effect on the decrease of soot and particulate number. At low and medium loads, the effect of methanol substitution percent on soot and particulate number emissions is dependent on the start of injection. The effect of methanol substitution percent on the decrease of particles strengthens as the start of injection is away from the top dead center. The inflection point of particulate number and soot emissions moves forward with the increased methanol substitution percent. Compared to pure diesel mode, the strong correlation between soot and smoke opacity does not exist on diesel/methanol dual fuel mode. However, the correlation between soot and smoke opacity comes back in usage of the diesel oxidation catalyst or exhaust gas recirculation on diesel/methanol dual fuel mode. Most of nitrogen dioxide and unburned hydrocarbons are reduced by the diesel oxidation catalyst on diesel/methanol dual fuel mode.

Differentiation between O2 and NO2 impact on PtOx formation in a diesel oxidation catalyst

NO oxidation activity of platinum-based catalysts undergoes reversible changes during operation in oxidative atmosphere typical for Diesel engine exhaust gas due to platinum oxides (PtOx) formation and reduction. In recent years, these changes were studied mostly with the mixtures containing both O2 and NO2 so that it was difficult to quantify individual impacts of the oxidants on PtOx formation. In this paper, Pt/Al2O3 catalyst deactivation and PtOx formation with O2 and NO2 was examined separately by the means of transient isothermal experiments at 150, 175 and 200 °C with alternating deactivation and probe periods. The largest extent of deactivation was detected at 175 °C where the NO conversion in the isothermal experiment dropped from 85% (reduced catalyst) down to 10% (steady-state PtOx level) over 4 h. The experimental data were then utilized for parameter evaluation in global kinetic model of NO oxidation on a diesel oxidation catalyst extended by the reactions describing PtOx formation and reduction. Though the rate coefficient for PtOx formation with NO2 is higher than with O2, the overall PtOx formation rate and the steady-state PtOx level are higher with O2 at typical component concentrations (8% O2 or 250 ppm NO2). Similar activation energies were observed for both PtOx formation reactions. Validity of the model was verified also at lower O2 and NO2 concentrations (4% O2 or 125 ppm NO2). The developed model is thus capable of sufficiently precise prediction of catalyst deactivation at various O2 and NO2 concentrations relevant to diesel exhaust gas.