Current Emission Regulations Research Articles

Study on Rates of NH3 Adsorption and Desorption in SCR on Various Engine Operation Conditions

Aging diesel engines on the road require the development of an after-treatment system to meet current emission regulations, and a reduction in NOx (Nitrogen Oxide) is significant. The SCR (Selective Catalytic Reduction) system is the after-treatment system for removing NOx from exhaust gas in diesel engines using NH3 (Ammonia) gas. However, the mixing and conversion process between NH3 and NOx in SCR has not been entirely clarified. That process produces NH3 slip in the catalyst surface; the NH3 slip will make the after-treatment performance worse. This study informs how the UWS (Urea Water Solution) injection controlling method can minimize the NH3 slip in the after-treatment system. For this, the NH3 adsorption and desorption rates are important factors for determining the quantity of UWS injection in the system. The NH3 adsorption rate and desorption rate in the SCR are not significantly affected by engine speed, i.e., the exhaust gas flow rate. However, as the exhaust gas temperature increased, the adsorption rate and desorption rate of NH3 in the SCR increased. Through this, the exhaust gas temperature dramatically affects the NH3 adsorption rate and desorption rate in the SCR. Therefore, if the urea water is injected based on this knowledge that the NH3 adsorption amount in the SCR decreases as the exhaust gas flow rate increases, NH3 slip can be suppressed and a high NOx reduction rate can be achieved. Therefore, if the SCR adsorption and desorption mechanisms are analyzed according to the exhaust temperature and the exhaust flow rate in this paper, it can be used as a reference for selecting an appropriate SCR when retrofitting an old diesel engine car.

Particulate number emissions during cold-start with diesel and biofuels: A special focus on particle size distribution

The share of biofuels in the transportation sector is increasing. Previous studies revealed that the use of biofuels decreases the size of particles (which is linked to an increase in particulate toxicity). Current emission regulations do not consider small particles (sub-23 nm); however, there is a focus in future emissions regulations on small particles. These and the fact that within cold-start emissions are higher than during the warmed-up operation highlight the importance of a research that studies particulate matter emissions during cold-start. This research investigates the influence of biofuel on PN and PM concentration, size distribution, median diameter and cumulative share at different size ranges (including sub-23 nm and nucleation mode) during cold-start and warm-up operations using diesel and 10, 15 and 20% mixture (coconut biofuel blended with diesel). During cold-start, between 19 and 29% of total PN and less than 0.8% of total PM were related to the nucleation mode (sub-50 nm). Out of that, the share of sub-23 nm was up to 9% for PN while less than 0.02% for PM. By using biofuel, PN increased between 27 and 57% at cold-start; while, the increase was between 4 and 19% during hot-operation. The median diameter also decreased at cold-start and the nucleation mode particles (including sub-23 nm particles) significantly increased. This is an important observation because using biofuel can have a more adverse impact within cold-start period which is inevitable in most vehicles’ daily driving schedules.

Impact of test cycle on mass, number and particle size distribution of particulates emitted from gasoline direct injection vehicles

This paper presents an investigation of emissions from gasoline direct injection (GDI) vehicles and analyzed the characteristics of emitted particulate matter (PM), the emission factors of particulate number (PN) and size distribution properties, including four test cycles: the new European driving cycle (NEDC), the worldwide harmonized light vehicle test cycle (WLTC), the USA federal test procedure-75 (FTP-75) and the China light-duty vehicle test cycle (CLTC). The results reveal that for China VI standard GDI vehicle, compared with CLTC, which is the newest test cycle according to realistic road conditions in China, the aforesaid evaluation indexes of FTP-75 and WLTC are basically higher due to their higher acceleration and deceleration ratio. Compared with hot start, a cold start followed by warming-up process has a significant impact on PN emissions over all test cycles and different test cycles show diverse sensitivity to the change of start-up conditions. The particles with a diameter of 5.6–23 nm (sub-23 nm) account for 43.1–57.7% of the total PN emission quantity for China V standard GDI vehicle, which is about 5–15% higher than that of theoretical assumptions. Different piecewise speed segments exhibited different impacts on PN characteristics when acceleration and deceleration reveal greater influence. Gasoline particulate filter (GPF) could effectively capture full-size particulates including fine particles as sub-23 nm particles, which is verified over FTP-75 and CLTC, while sub-23 nm PN emission is still at a high level over WLTC for its ultrahigh speed segment. There could have been an underestimation of the real particle number emitted from GDI vehicle while the emission of solid sub-23 nm particles was excluded under current emission regulations.

Chemical Effects of CO2 and H2O Addition on Aromatic Species in Ethanol/Air Diffusion Flame

ABSTRACT Exhaust gas recirculation (EGR) is an effective technique used widely to meet current emission regulations. In this work, the mechanism of H2O and CO2 addition (a main component of exhaust gas) on polycyclic aromatic hydrocarbons (PAHs, the precursor of soot) formation was investigated numerically in ethanol diffusion flames, motivated by current concerns on particulate matter (PM) emissions when ethanol is applied to modern gasoline engines, especially under high load and temperature. To understanding the underlying mechanisms of H2O and CO2 on ethanol flame, a comprehensive chemical kinetic analysis was performed by modeling gas-phase chemistry with PAHs formation up to pyrene. In order to distinguish the important chemical role of H2O and CO2 addition through partial replacement of N2 from their thermal effects, additional calculations were performed with two fictitious species. The numerical results show that the thermal effect of H2O and CO2 reduces the peak flame temperature, but their chemical effect influences the peak flame temperature differently. The results also showed that the addition of either H2O or CO2 led to a significant reduction of PAHs via thermal and chemical effects. The chemical suppressing effect of H2O and CO2 addition on PAHs formation was identified and attributed to reduced PAHs precursor species and slow of PAH growth process. However, reaction pathway analysis showed that the chemical effects of H2O and CO2 influence the PAHs chemistry differently.

Sustainable Mobility Using Fuels with Pathways to Low Emissions

<div class="section abstract"><div class="htmlview paragraph">Regulations around the globe are driving the adoption of alternative fuels and vehicles through the implementation of stricter standards aimed at reducing carbon footprint and criteria emissions such as nitrogen oxides (NO<sub>x</sub>), particulate matter (PM), and total hydrocarbon (THC) emissions. Low emission zones have been implemented across Europe which restrict access by some vehicles with the aim of improving the air quality. The Paris Agreement on climate change declared governments’ intentions to reduce greenhouse gas (GHG) emissions as outlined in each country’s nationally determined contribution. Providing affordable energy to support prosperity while reducing environmental impacts, including the risks of climate change, is the dual challenge for the energy and transport industries.</div><div class="htmlview paragraph">Development and deployment of low-emission liquid fuels and complementary engine hardware optimization could provide options to meet air quality as well as proposed, ambitious greenhouse gas (GHG) reduction targets. To take advantage of these potential benefits, these fuels must be compatible with the existing fleet and comply with current fuel standards. This work represents a joint effort by Porsche and ExxonMobil Research & Engineering Company. The goal of this work is to evaluate the potential of low-emission fuels to improve tailpipe emissions from in-use and new vehicle fleets.</div><div class="htmlview paragraph">In this study, a number of fuels with various qualities and low-emissions potential were tested for resulting criteria emissions (NO<sub>x</sub>, PM, THC). A research Porsche single cylinder engine, including advanced engine combustion design elements, was used for combustion and emissions analysis. The tests were done under stationary and dynamic load as well as under different temperature conditions.</div><div class="htmlview paragraph">Significant reductions to criteria emissions were obtained with the new fuel formulations, when compared to an existing European market fuel. Reductions of more than 90% in particulate emissions, 10 to 20% in NO<sub>x</sub> emissions, and up to 30% in THC emissions were achieved. Additionally, vehicle test results on both, a 1996 993 and a 2016 991.2 Porsche Carrera, with some selected fuels are presented and compared. Emission reduction potential with the 993 (23 years old vehicle) were similar to the 991.2 by using the low emission formulations showing the potential of the fuels in legacy vehicles, not equipped with gasoline particulate filters (GPF), to comply with current emission regulations. Furthermore, these fuels can be formulated to be compliant with existing European fuel regulations.</div></div>

Chemical Mechanism of Exhaust Gas Recirculation on Polycyclic Aromatic Hydrocarbons Formation Based on Laser-Induced Fluorescence Measurement

Exhaust gas recirculation (EGR) has been widely used in engines to meet current emission regulations. Investigating the chemical mechanism of EGR on polycyclic aromatic hydrocarbons (PAHs, the precursor of soot) formation in premixed flames contributes to understanding the EGR dependence on soot formation in engines. In this study, the influence of flame temperature, equivalence ratio, and CO2 addition on the formation of PAHs was systematically investigated in premixed C2H4/O2/Ar/CO2 flames using laser-induced fluorescence (LIF) technology. The temperature dependence of PAHs formation was studied at a fixed equivalence ratio and dilution ratio. It was found that the LIF signal of PAH reaches the maximum value around 1730 K and decreases at a lower or higher temperature in this study. The LIF signal of PAHs almost increases linearly with the equivalence ratio, as the maximum flame temperature and dilution ratio are kept constant. The experimental results show that the CO2 addition in the inlet gas suppres...

Evaluation and optimization of the structural parameter of diesel nozzle basing on synchrotron radiation imaging techniques

Lacking of efficient methods, industry currently uses one only parameter—fuel flow rate—to evaluate the nozzle quality, which is far from satisfying the current emission regulations worldwide. By utilizing synchrotron radiation high energy X-ray in Shanghai Synchrotron Radiation Facility (SSRF), together with the imaging techniques, the 3D models of two nozzles with the same design dimensions were established, and the influence of parameters fluctuation in the azimuthal direction were analyzed in detail. Results indicate that, due to the orifice misalignment, even with the same design dimension, the inlet rounding radius of orifices differs greatly, and its fluctuation in azimuthal direction is also large. This difference will cause variation in the flow characteristics at orifice outlet and then further affect the spray characteristics. The study also indicates that, more precise investigation and insight into the evaluation and optimization of diesel nozzle structural parameter are needed.

Analysis of the effects of meteorology on aircraft exhaust dispersion and deposition using a Lagrangian particle model

The risk of air quality degradation is of considerable concern particularly for those airports that are located near urban areas. The ability to quantitatively predict the effects of air pollutants originated by airport operations is important for assessing air quality and the related impacts on human health. Current emission regulations have focused on local air quality in the proximity of airports. However, an integrated study should consider the effects of meteorological events, at both regional and local level, that can affect the dispersion and the deposition of exhausts. Rigorous scientific studies and extensive experimental data could contribute to the analysis of the impacts of airports expansion plans.This paper is focused on the analysis of the effects of meteorology on aircraft emission for the Marco Polo Airport in Venice. This is the most important international airport in the eastern part of the Po’ Valley, one of the most polluted area in Europe. Air pollution is exacerbated by meteorology that is a combination of large and local scale effects that do not allow significant dispersion. Moreover, the airport is located near Venice, a city of noteworthy cultural and architectural relevance, and nearby the lagoon that hosts several areas of outstanding ecological importance at European level (Natura 2000 sites).Dispersion and deposit of the main aircraft exhausts (NOx, HC and CO) have been evaluated by using a Lagrangian particle model. Spatial and temporal aircraft exhaust dispersion has been analyzed for LTO cycle. Aircraft taxiing resulted to be the most impacting aircraft operation especially for the airport working area and its surroundings, however occasionally peaks may be observed even at high altitudes when cruise mode starts. Mixing height can affect concentrations more significantly than the concentrations in the exhausts themselves. An increase of HC and CO concentrations (15–50%) has been observed during specific meteorological events.

CHARACTERIZATION OF PERODUA MYVI K3-VE I4 ENGINE PERFORMANCE USING EXHAUST GAS RECIRCULATION (EGR)

Internal combustion engines are the main power source for automobile vehicles. As current emission regulations becomes more stringent, more fuel efficient and less polluting engines are becoming the focus of car manufacturers. This paper presents the study of improving the performance of K3-VE I4 internal combustion engine that is used in the Perodua Myvi for the Perodua Eco-Challenge 2013. The strategy was to use an EGR system to reduce Brake Specific Fuel Consumption (BSFC) while maintaining or increasing the engine power. The effects of different location of EGR on the engine performance were tested on a chassis dynamometer. The sensitivity of the engine performance and gas emission were studied since EGR implementation plays a major role in influencing NOx emission. The performance parameter such as engine power and BSFC were then analysed. The result shows that a significant increase of power can be achieved and a reduction of around 56% was obtained on the BSFC. While the best NOx reduction was around 93%. These improvements are obtained at low RPM that corresponds to Perodua Eco-Challenge’s objective.

Global-Mean Temperature Change from Shipping toward 2050: Improved Representation of the Indirect Aerosol Effect in Simple Climate Models

We utilize a range of emission scenarios for shipping to determine the induced global-mean radiative forcing and temperature change. Ship emission scenarios consistent with the new regulations on nitrogen oxides (NO(x)) and sulfur dioxide (SO(2)) from the International Maritime Organization and two of the Representative Concentration Pathways are used as input to a simple climate model (SCM). Based on a complex aerosol-climate model we develop and test new parametrizations of the indirect aerosol effect (IAE) in the SCM that account for nonlinearities in radiative forcing of ship-induced IAE. We find that shipping causes a net global cooling impact throughout the period 1900-2050 across all parametrizations and scenarios. However, calculated total net global-mean temperature change in 2050 ranges from -0.03[-0.07,-0.002]°C to -0.3[-0.6,-0.2]°C in the A1B scenario. This wide range across parametrizations emphasizes the importance of properly representing the IAE in SCMs and to reflect the uncertainties from complex global models. Furthermore, our calculations show that the future ship-induced temperature response is likely a continued cooling if SO(2) and NO(x) emissions continue to increase due to a strong increase in activity, despite current emission regulations. However, such cooling does not negate the need for continued efforts to reduce CO(2) emissions, since residual warming from CO(2) is long-lived.

Liquid wood: Direct combustion of wood in a gas turbine to produce electricity and heat

A small group of technologists in the South of England, have been working, since 1995, with the assistance of the UK Government's SMART programme and also some European Union support, on fuelling a gas turbine by the direct combustion of wood. Their intellectual property is based on the novel technology that causes the wood particles to burn with combustion kinetics more typical of a liquid. Bioturbines Ltd, was formed in 1999 to exploit the technology, which the company claims, requires significantly lower capital cost and yields higher cycle efficiency, than competing technologies that involve gasification or steam-raising plant. The total system is CO 2 neutral and measurements made on the 50kWe prototype give every confidence that current emission regulations will be met. The patent application is in the final stages of the patenting process and the opportunity to obtain a licence for the manufacturing or marketing of the technology is available to companies interested in entering this challenging field.

Investigation on the emission factors and removal efficiencies of heavy metals from MSW incinerators in Taiwan.

Two large-scale municipal waste incinerators (MWIs) equipped with different air pollution control devices (APCDs) were selected for conducting flue gas sampling and determination of heavy metals emissions including lead, zinc, cadmium, chromium, copper and mercury. In addition, the emission characteristics and removal efficiencies of heavy metals were evaluated via simultaneous sampling of flue gas upstream and downstream of APCDs. The average removal efficiency of particulate matter was 99.47%, and the removal efficiency of heavy metals could reach 95% or higher (except for Hg) for MWI-A. Preliminary results indicated that the average removal efficiency of particulate matter was 99.94%, and the removal efficiency of heavy metals could reach 98% or higher (except for Hg) for MWI-B. The average removal efficiencies of Hg for MWI-A and MWI-B were 47% and 30% respectively. The removal efficiencies achieved with existing APCDs were close to that reported in the US EPA document (AP-42) for MWIs. The average concentrations of heavy metals and particulate matter emitted from stack could meet current emission standards in Taiwan for both MWIs, but particulate matter, Pb and Cd concentrations of MWI-A were higher than the current emission regulations in Germany and the Netherlands.

Emissions of Metal and Organic Compounds from Cement Kilns Using Waste Derived Fuels

Research completed to date suggests that the use of waste as a substitute fuel in cement kilns is fundamentally sound in theory, and in a number of cases, has been demonstrated sound in practice. Analysis of the database generated in certificate of compliance tests clearly demonstrate that cement plants burning waste-derived fuel (WDF) can employ existing technology to meet and in some cases exceed current emission regulations. With the exception of cement kilns using raw materials with high levels of hydrocarbons, the emission of organics can be controlled by applying well-established good-combustion practices. Metals emissions from cement plants burning WDF can be predicted based upon input metal flow rates, provided that plant-specific information on the collection efficiency of air pollution control equipment and by-pass flow rates are available.

On the feasibility of process steam production options in Turkey

A computer model called “INDUSTEAM” has been developed to investigate the technical, environmental and economic feasibility of various steam production options in Turkey. Low and high sulphur fuel-oil and natural gas based systems are included in the analysis as imported sources of primary energy. The suitability of indigeneous coals for industrial steam production is analysed with special emphasis on low-grade lignite utilization. Traditional grate firing and the bubbling and circulating bed alternatives of atmospheric fluidized bed combustion are the selected coal-based options. The model involves consideration of compliance with current emission regulations and utilization of data compiled via a thorough survey of foreign and domestic markets. A capacity range of 10–90 MW th for steam production at three different temperatures and pressures is covered. Economic results are presented using three different indicators, namely, levelized energy costs, investment costs, and pay-back periods.