Catalyst Converter Research Articles

An Experimental Study on the Emission Characteristics in CI Engine using Nano Particle Coated Catalytic Converter

A proven viable technology to reduce vehicular exhaust gas emission is the catalytic converter. Although catalyst converters are an effective and efficient method to react to certain pollutants, they are expensive due to the use of noble metals like palladium, platinum and rhodium. Various research has been carried out to find a viable alternative to the noble metal catalyst that can react over vehicular pollutants such as oxides of nitrogen (NOx), carbon monoxide (CO), unburnt hydrocarbon (UBHC) and particulate matter (PM) emitted by the combustion of hydrocarbon burnt internal combustion engine. This paper investigates the emission characteristics of a nano-particle-coated catalytic converter in a conventional fossil-fuelled compression ignition engine. The catalyst used in the research is a nano-particle of metal oxides such as aluminium oxide (nano-sized Al2O3) particle and titanium oxide nano-sized (TiO2) particle. This catalyst is less expensive compared to a noble catalyst. Experiments were made on a single cylinder four strokes water-cooled diesel-fuelled compression ignition engine with a catalytic converter coated with alternative nano-particles. The exhaust gas was allowed to pass through the nano-sized catalyst deposited over the honeycomb structure of the substrate of the catalytic converter and the emission was measured using a five-gas analyser. The result showed a decreased level of oxides of nitrogen.

Laser powder bed fusion of Alumina/Fe–Ni ceramic matrix particulate composites impregnated with a polymeric resin

Additive Manufacturing (AM) plays a key role in meeting the vital demands of Industry. The AM industry needs the range of applicable materials to be expanded by conducting research on novel ones. In the present investigation, alumina/Fe–Ni (steel) ceramic matrix particulate composite was fabricated employing laser powder bed fusion (LPBF) additive manufacturing (AM) technology. The quality of the printed samples was associated with the LPBF process parameters, which were optimized for this process. In general, the fabricated samples showed a microstructure of alumina matrix with uniform distribution of steel (Fe–Ni) particles. The as-printed samples exhibited pores. Thus, they were subjected to a sintering heat treatment cycle under an inert atmosphere. Although the sintering cycle considerably increased the average Vickers hardness, pores were not eliminated entirely. Therefore, polymer impregnation of the as-sintered samples was carried out to reduce porosities and microcracks. The mercury porosimeter showed that the porosity decreased sequentially after sintering and polymer impregnation. In addition, mechanical investigations revealed that the polymer impregnation improved the compressive strength of the sintered samples (from 56 to 120 MPa). Alumina-based materials find wide applications in various fields, including the manufacturing of electronic components, cutting tools, biomedical implants, and catalyst converters, owing to their low density, high hardness, wear and corrosion resistance, and biocompatibility. This study presents a viable approach for the fabrication of these materials, with developed samples exhibiting promising properties. The study emphasizes the potential of additive manufacturing as an approach for the fabrication of ceramic matrix composites reinforced with metallic particulates in future research.

Assessing methods for the production of renewable benzene

Benzene is a widely used chemical feedstock without an alternative in polymer and high energy density liquid fuel production. Produced from fossil carbon, benzene consumption contributes to rising atmospheric CO2 levels at the end of life. Several low maturity routes to produce fossil carbon- free, renewable benzene are being developed, each with merits and shortfalls. However, analysis is lacking to evaluate how these routes compare and assess which show the most potential in a sustainability context. Here, nine diverse approaches to renewable benzene production are evaluated using a multi-step Multi-Criteria Decision Analysis (MCDA) technique across indicators in three sustainability categories: ‘People’, ‘Profit’, and ‘Planet’ (3Ps). Three example scenarios are presented to elucidate how stakeholder preference may inform weighting choices and hence outcome. In all cases, the use of Fe/Fe3O4 nanoparticle catalysts with CO2/H2 feed consistently ranked highest with HZSM-5 catalyst converting lignin feed ranked second. Notably, these routes are exemplified by the simplicity of their respective processes. However, due to the emerging nature of all routes, assessment rankings are likely to change with developmental research and subsequent scale-up. It is probable that any deployed technology would combine a variety of attributes rather than utilise any single route assessed here. Hence, positive and negative hotspots are identified. For example, Zn-ZrO2 nanoparticles on HZSM-5 exhibit exceptional catalyst lifetime, while many locations may lack the infrastructure to produce nanocatalysts, restricting choice of route. Therefore, an open-access model included with this work allows new routes to be added, process data to be updated and priorities altered. This enables practitioners to continue to assess new routes and improvements. Ultimately, the route decision will depend highly on geographic location, local availability of a given feedstock and compatibility with an effective catalyst.

On-road tailpipe characterization of exhaust ammonia emissions from in-use light-duty gasoline motor vehicles

A Portable Emissions Monitoring System (PEMS) has been used to estimate ammonia emission rates from a representative fleet of 47 in-use light-duty gasoline motor vehicles over 145 on-road Real Driving Emissions (RDE) tests. The PEMS modules were carried onboard the tested vehicles and were wired such that their ceramic exhaust emission sensors were mounted directly in the tailpipe. The on-road RDE tests were conducted over an urban testing route that included residential and highway roads, uphill and downhill road segments, stop signs, traffic lights, and a school zone with a reduced speed limit. The entire vehicle test sample had an average ammonia emission rate of 114.7 mg/mile ±135.3 (StD). This would yield an estimated 2909 metric tons per year of NH3 emissions from the Wasatch fleet on-road gasoline motor vehicles. Old vehicles with aged Three-Way Catalyst (TWC) converters had higher NH3 emissions rates than newer vehicles with newer TWC converters. For instance, Tier 0, Tier I, NLEV, Tier II and Tier III vehicles had average emission rates of 563.1, 177.8, 213.6, 94.4 and 18.9 mg/mile, respectively. Carbon monoxide, and nitrogen oxides had a strong correlation with ammonia emission rates, with r ≥ 0.70. A Moderate correlation was found with vehicles’ mileage (r = 0.6), model year (r = −0.5), engine displacement (r = 0.4), and number of cylinders (r = 0.4). The outcomes highlight vehicle contributions to the atmospheric NH3 inventory and the impact of vehicle characteristics and ammonia precursor concentrations on ammonia emission rates from gasoline vehicles.

Design and Analysis of X Shaped Exhaust System Operation Using Different Types of Profiles on High Capacity Vehicle

The exhaust system used in a 4-stroke IC engine is mounted on the cylinder head of an engine. The gases exhausted from the engine recollected by the exhaust system and it is sent to a catalyst converter. The exhaust manifold has an important role in the performance of an engine system. The exhaust manifold affects the efficiencies of emission and fuel consumption. During the process of collecting the gas from engine and exhaust to catalyst converter, the exhaust manifold experiences temperatures of 800°c and the pressures varying from 100 to 500kpa. Here in this thesis we are going to choose a 4 cylinder 1500cc diesel engine of a car. In this paper, design of the original model and the modified models of X shaped systems using Catia software and then analysed using CFD software for the flow rates and the temperature distribution of the exhaust models. Finally better modification can be determined.

Water evaporation model of a catalyst converter in the context of hybrid electric vehicles energy and pollutants management

The energy and pollutants management of Hybrid Electric Vehicles (HEV) consists in determining at each instant the optimal torque split between the Internal Combustion Engine (ICE) and the Electric Motor (EM). This torque choice aims to minimize both fuel consumption and pollutants emissions. A critical piece of information in this context is the value of the Three-Way Catalyst Converter (3WCC) conversion efficiency. This value is highly dependent on the 3WCC temperature; it is hence of major importance to have an accurate estimation of it. Although the literature is abundant about simple 0D thermal models of 3WCC, it is tempting to implement a more accurate and consequently complex model. In particular, both moisture from the exhaust gases during engine start and from ambient air during cooling phases lead to the formation of a liquid water film on the monolith’s exchange surface, causing a strong temperature plateau during the warm-up phase. The water evaporation causing a delay in the 3WCC temperature increase, it could lead to a serious degradation of the pollutants emissions if not taken into account. This paper proposes hence a 1D thermal model including water phase changing that allows a 72% decrease in the 3WCC temperature estimation error during the warm up phase. This accuracy gain, occurring in a phase where the converter temperature has not reached its full efficiency, provides a 1-2% reduction in CO, HC and NO x emissions.

Selective carbene transfer to amines and olefins catalyzed by ruthenium phthalocyanine complexes with donor substituents.

Electron-rich ruthenium phthalocyanine complexes were evaluated in carbene transfer reactions from ethyl diazoacetate (EDA) to aromatic and aliphatic olefins as well as to a wide range of aromatic, heterocyclic and aliphatic amines for the first time. It was revealed that the ruthenium octabutoxyphthalocyanine carbonyl complex [(BuO)8Pc]Ru(CO) is the most efficient catalyst converting electron-rich and electron-poor aromatic olefins to cyclopropane derivatives with high yields (typically 80-100%) and high TON (up to 1000) under low catalyst loading and nearly equimolar substrate/EDA ratio. This catalyst shows a rare efficiency in the carbene insertion into amine N-H bonds. Using a 0.05 mol% catalyst loading, a high amine concentration (1 M) and 1.1 eq. of EDA, a number of structurally divergent amines were selectively converted to mono-substituted glycine derivatives with up to quantitative yields and turnover numbers reaching 2000. High selectivity, large substrate scope, low catalyst loading and practical reaction conditions place [(BuO)8Pc]Ru(CO) among the most efficient catalysts for the carbene insertion into amines.

Making precious metals cheap: A sonoelectrochemical – Hydrodynamic cavitation method to recycle platinum group metals from spent automotive catalysts

Platinum group metals, such as Pd and Pt, found in three-way catalyst converters were recycled in a two-step method: hydrodynamic cavitation followed by sonoelectrochemical dissolution. High shear forces were obtained by using a convergent nozzle with a throat diameter of 0.2 mm, feeded by a plunger pump at a pressure of 60 MPa. Cavitating submerged jets acted locally on the water dispersed waste catalyst. As-obtained samples were analyzed by scanning electron microscopy and transmission electron microscopy. Electron microscopy on the initial sample showed that round shaped Pd and Pt nanoparticles were randomly distributed on the Al2O3 matrix. Cavitated samples show two zones in which Pt and Pd were partially and completely separated from the cordierite. The hydrodynamic cavitation separates the Pd and Pt from the cordierite leading to an apparent increase in Pd and Pt concentrations of 9% and 34% respectively. Conventional electrochemistry showed a dissolution of 20% in 1 h. To further accelerate the dissolution, a sonotrode operating at 20 kHz and 75 W was placed inside an electrochemical cell in order to increase the mass transport and obtain high dissolution rates. Indeed, the results showed that 40% of the available Pd and Pt can be recycled in just 1 h. In the absence of hydrodynamic cavitation and using conventional electrochemistry less than 10% of the available Pt and Pd is recovered in 1 h. The cost analysis showed that Pd and Pt can be recovered at less than 10 EUR per g which is 5 times smaller than their current market price.

Design and Analysis of Exhaust Manifold

The exhaust manifold system is mountedon the cylinder head of theengine. It is associated with the catalyst converter at the other end. The emitted gases transmitted from the chamber come out at temperatures of about 800 °C and with pressures extending from 100 to 500 kPa. The exhaust manifold system is exposed to high temperatures and weights which will lead to thermo mechanical failure. Redesigning an exhaust manifold by determining Thermal stresses and deflections exhibited under various operating conditions with different materials and temperatures. The objective is to ensure the suitability of the design for a particular material from the view point of reliability and serviceability. Defects in existing manifold are cracks usually occur due to prolonged exposure to extreme temperatures, defects in casting and Heat cycling. High end cad cam software such as Unigraphics and Ansys is used for modeling and analysis. The 3d Model of exhaust manifold is subjected to thermal and structural loads and results are tabulated according to the procedure for the Exhaust manifold.

Review of rapid ageing testing methods of three-way catalyst for gasoline engine

Recently, many advanced automotive companies around the world have developed rapid ageing methods for their three-way catalyst (TWC) converters. However, the systematic summary of related research progress is still lacking. Therefore, this work introduces TWC equivalent ageing mechanism, classifieds and summarises the current typical rapid ageing technology for TWC. The primary ageing of TWC on gasoline vehicle is thermal ageing, and the equivalent ageing theory is based on the Arrhenius equation. The current rapid ageing technology for TWC, including vehicle ageing, engine bench ageing, and burner ageing. There are three kinds of modes for engine bench ageing, which are single mode, two-mode and multimode ageing cycle. Introduces the common two-mode and multi-mode ageing cycle in detail. Meanwhile, the paper compares the characteristics of different ageing technologies. In general, engine bench ageing methods and burner ageing methods take less time, manpower and consumable cost than traditional vehicle ageing, but there is a certain deviation from the actual vehicle ageing effect.

Modelling and Fuzzy-Threshold Control of SI Engine for Emission Reduction during Cold Start Phase

We present a controllable model of an internal combustion engine that captures the overlapping of the cylinder valves as a controllable parameter and its effect on engine efficiency and EGR rates. The model parameters have been calibrated for the EF7 engine and validated with experimental data. This model successfully estimates the performance and HC and NOx emissions concentration of the engine under cold start operating condition. A model-based fuzzy-threshold control strategy has been proposed in cold start operating condition. This strategy uses the overlapping angle of the cylinder inlet and outlet valves as an extra degree of freedom in comparison to the regular PID strategy in order to accelerate the warm-up duration the catalyst converter while reduces the exhaust harmful emissions during the warm-up phase. The proposed controller model has been verified in MATLAB Simulink environment and simulation results indicates 8.6% reduction of the start-up time of the catalyst converter and reduction of 3.5%, 8.5% and 7% of HC, NO and fuel consumption respectively during the catalyst warm-up phase.

Nucleation mode particle evolution in a gasoline direct injection engine with/without a three-way catalyst converter

For gasoline direct injection (GDI) engines, as the exhaust gas temperature decreases, the hydrocarbon-to-particle conversion may occur, generating nucleation mode particles. A three-way catalyst converter (TWC) may have effects on the particle evolution as exhaust temperature decreases. In the present study, the effects of TWCs on particulate matter emissions and hydrocarbon-to-particle conversion process under different exhaust gas temperatures are researched.The particle size distributions are compared between the pre-TWC (upstream of the TWC) and post-TWC (downstream of the TWC) positions. Results show that the reduction of total particle number concentrations is 40–80% after exhaust gas passes the TWC, which is higher at higher load. The TWC has higher reduction efficiencies for particles in smaller size ranges. In the size range of 4–8 nm, the reduction efficiencies for particles are more than 96%. For particles larger than 50 nm, the TWC doesn’t show remarkable effects on particle number (PN) concentrations.The particle evolution and the hydrocarbon-to-particle conversion with regard to the exhaust gas temperatures are also investigated. At the post-TWC position, the PN concentrations of nucleation mode are much lower compared with those of accumulation mode, and not sensitive to exhaust temperature variations. The PN concentrations of nucleation mode at the pre-TWC position with the sampling temperature of 170 °C are slightly higher than those at the post-TWC position. PN concentrations of nucleation mode at the pre-TWC position increase sharply when the sampling temperature decreases from 110 °C to 50 °C. It is suggested that TWCs don’t convert the nucleation mode particles directly, but remove those semi-volatile hydrocarbon components as precursors of nucleation mode particles forming in low exhaust temperatures.

Influence of composite after-treatment catalyst on particle-bound polycyclic aromatic hydrocarbons–vapor-phase emitted from modern advanced GDI engines

With mutagenic and cacogenic potential polycyclic aromatic hydrocarbons (PAHs) generated from engine source which have contributed to a substantial share of air toxic, so in order to characterize and eliminate the PAHs emissions of commercial engine fuelled, an experimental study has been carried out on a V6 gasoline engine working in spark-ignition (SI) and homogeneous charge compression ignition (HCCI) equipped with smart three-way catalyst converter (TWC). The particle phase and gas phase of PAHS in engine exhaust, downstream and upstream the catalyst were collected by stainless-steel cartridges containing XAD-2 resin to capture PAHs species. The vapour phase and particulate bound PAHs compounds observed with two and three rings to exist almost entirely in the gas phase, on the other hands, five or more fused rings are predominantly adsorbed on soot particles, the intermediate – 4 ring PAHS exist in the two PAHS phases, naphthalene is the most abundant polycyclic aromatic hydrocarbon that was detected in the exhaust vapour-phase on both engine modes. The prototype catalytic converter eliminates most of the polycyclic aromatic hydrocarbons species in both PAHS phases, particle phase and gas phase, except for NAP species. A prototype catalyst showed higher efficient conversion on PAHS particulate-bound phase than vapor phase for both engine modes. However, when hydrogen was added upstream of the catalyst, the catalyst conversion efficiency in reducing naphthalene was increased by approximately 20%.

NOx adsorption on K and Ba loaded on zirconia-titania NSR catalysts: A comparative study by in situ and operando IR spectroscopy

An intensive in situ and operando IR study on NOx adsorption over potassium (K) loaded zirconia-titania NSR catalyst in comparison to a barium (Ba) loaded one is reported. Based on in situ IR experiments, NOx adsorption under heated environment was confirmed to favor potassium bidentate nitrate species rather than ionic nitrate species observed for Ba-loaded NSR catalyst (previously published). Complementary operando IR experiments revealed different mechanisms for NOx adsorption over the two NOx storage materials (NSMs): initial simultaneous NO2− and NO3− formation over K loaded catalyst while over Ba-loaded one, NO2− is first accumulated before being converted to NO3−. Isotopic labelling in combination with operando experiments identified distinct dynamic behaviors regarding the exchange between nitrogen containing species on surface and in gas phase. This work provides beneficial inputs for advanced catalyst converter design, for example with zone-coated washcoat that contains more than one catalyst formulations.

Evaluating real-world emissions of light-duty gasoline vehicles with deactivated three-way catalyst converters

Three-way catalyst (TWC) converter is one of the most important after-treatment device for modern light-duty gasoline vehicles (LDGVs), which can efficiently control exhaust emissions of carbon monoxide (CO), total hydrocarbons (THC) and nitrogen oxides (NOX). Nevertheless, a considerable part of in-use taxis in Beijing would operate with TWC purposely removed, which have been indicated by vehicular on-board diagnostic (OBD) systems. In light of high vehicle-use intensity for taxis, we recruited three China 4 non-TWC taxis and three China 4 normal taxis in a comparative experimental test by using a portable emissions measurement system (PEMS). The results indicated that non-TWC taxis emitted significantly higher emissions of air pollutants than normal taxis with TWC functioning. For example, average emission factors of non-TWC vehicles were comparable to emission levels of China 1 LDGVs measured in previous studies. By contrast, emissions from normal China 4 taxis were all below China 4 emission limits. Furthermore, an operating mode binning method and a micro-trip approach have been employed to link vehicle emissions with driving conditions. For non-TWC taxis, we identified strong correlations of all pollutant categories between emission factors and average speed. However, such correlations for normal taxis were less strong, in particular for CO and THC emissions that were hardly sensitive to speed changes. This phenomenon indicates that the role of traffic conditions in affecting real-world emissions would become weaker when TWC can effectively mitigate emissions. This paper highlights the importance of in-use emission inspection to avoid any “high emitters” that have violated regulation enforcement.

Effect of electrically heated catalytic converter on emission characteristic of a motorcycle engine in cold-start conditions: CFD simulation and kinetic study

Emissions from motorcycles are well known to be a serious cause of environmental pollution. One of the most effective ways to reduce the emissions during cold start of the motorcycle engine is using electrically heated catalytic converters (EHC). In this study, a kinetic model has been developed by using CFD methods to investigate the effects of using EHC on CO emission from motorcycle engines. Apart from three different heating temperatures (600, 800 and 1000K), the other studied parameters included the heating position (the inlet and the mid-section of the catalyst converter) and heating duration (20, 25 and 35s). Results showed that using the heater at the inlet of the catalytic converter is more effective than when it is in mid-section and the converter has a higher reaction performance. Moreover, the results indicated that the minimum heating temperature which required the converter to reach the light-off point is 450K. In addition, the results revealed that when the heaters were turned on prior to cold starting the engine for duration of 35s, the higher CO conversion occurs.

세라믹 필터 집진기의 유동 해석

This study aimed to analyze the fluid inside the ceramic filtration dust collection system which was assumed to be a stationary 3-dimensional turbulence. The fluid dynamics data necessary for performance curves were obtained based on the analysis results. The governing equations used to compute the velocity distribution and pressure inside the catalyst converter were expressed with continuity and momentum equations. Furthermore, the <TEX>${\kappa}-{\varepsilon}$</TEX> turbulence model, already validated by the industry(coal factory, high temperature dust collector) was used for the study. Of a total of three computational models employed, Model-1 served as the basis for CFD analysis which took measurements in increments of 70mm.

Modeling hydrodynamic flows in plasma fluxes when depositing metal layer on the surface of catalyst converters

Air pollution with harmful substances resulting from combustion of liquid hydrocarbons and emitted into atmosphere became one of the global environmental problems in the late 20th century. The systems of neutralization capable to reduce toxicity of exhaust gases several times are very important for making environmentally safer combustion products discharged into the atmosphere. As revealed in the literature review, one of the most promising purification procedures is neutralization of burnt gases by catalyst converter systems. The principal working element in the converter is a catalytic layer of metals deposited on ceramics, with thickness 20-60 micron and a well-developed micro-relief. The paper presents a thoroughly substantiated new procedure of deposing a nano-scale surface layer of metal-catalyst particles, furthering the utilization of catalysts on a new level. The paper provides description of mathematical models and computational researches into plasma fluxes under high-frequency impulse input delivered to electrode material, explorations of developing Kelvin-Helmholtz, Marangoni and magnetic hydrodynamic instabilities on the surface of liquid electrode metal droplet in the nano-scale range of wavelengths to obtain a flow of nano-meter particles of cathode material. The authors have outlined a physical and mathematical model of magnetic and hydrodynamic instability for the case of melt flowing on the boundary with the molten metal with the purpose to predict the interphase shape and mutual effect of formed plasma jet and liquid metal droplet on the electrode in the nano-scale range of wavelengths at high-frequency impact on the boundary “electrode-liquid layer”.

The Measurement Situation of Concentrations of Gaseous Hydrocarbons

Nowadays, there is an increasing number of vehicles on the road, and because of that, the air pollution is more serious than before. Although there is a three-way Catalyst Converter in every car, which can transform the CO, HC and NOX to the harmless ingredients like H2O from the exhausted fumes. It is not sure that all the gas, such as: HC can be transform entirely. Thus, many vehicle manufactures intend to find some equipment to control and measure the concentration of hydrocarbons from exhausted fumes to meet the requirement of vehicle emission of world standard. This report may help the vehicle companies to solve this problem. This report first mainly describes the specific chemical types of the gaseous hydrocarbon in exhausted fume which are Alkanes, Alkenes, Alcohols, and Ether. And it also posts the disadvantages of these toxic chemicals in exhausted fumes, for instance, it is harmful to human and it pollutes the environment. Secondly, the report introduces some approaches to measure the concentration of hydrocarbon in exhausted fume from vehicles, for examples, Mass Spectrometry and Gas Chromatography, The flame ionization detector, Infrared spectroscopy, and Raman Spectrum. Furthermore, these approaches are used as a medium to find the companies who can provide such equipment to test the concentration of hydrocarbon: Horiba, AVL, and Ocean Optics. The third, the product data from these three companies is listed and compared with each other. Finally, the evaluation result of instruments to measure the concentration of gaseous hydrocarbons is shown as an input to vehicle manufactures.

A selective dynamic sorption-filtration process for separation of Pd(II) ions using an aminophosphine oxide polymer

Abstract In order to develop an industrially applicable method for the use of phosphine oxide-based powder material for the capture and concentration of platinum group metals (PGM) from acidic effluents, a two stage process is proposed in this work. The process steps involve coupling the metal sorption on the powder in a continuous stirred tank reactor (CSTR) with a microfiltration PTFE membrane enabling a subsequent stripping of the metals concentrated on the powder material using an acidified solution of thiourea. Using a model solution with 0.6 mM Pd(II) in HCl and common metals as impurities (0.6 mM of Ni(II) and Cu(II) each), the process was conducted for several cycles leading to the final solution containing up to 9.8 mM of Pd(II) with a purity of around 90%. In addition, this process was successfully applied to a leachate of a car catalyst converter, that contained not only palladium, but also platinum, rhodium, as well as large excess of aluminum, cerium and iron. We have thus arrived at a robust process for concentrating effluents containing precious metals, achieving high concentration factors and purities of the final stream, while having low material loss and/or fouling of equipment.