Reduction Of Particulate Emissions Research Articles

Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Due to worldwide increasingly sharpened emission regulations, the development of Gasoline Direct Injection and Diesel Direct Injection engines not only aims at the reduction of the emission of nitrogen oxides but also at the reduction of particulate emissions. Regarding present regulations, both tasks can be achieved solely with the help of exhaust after treatment systems. For the reduction of the emission of particulates, Gasoline (GPF) and diesel Particulate Filters (DPF) offer a solution and their implementation is intensely promoted. Under optimal conditions particulates retained on particulate filters are continuously oxidized with the exhaust residual oxygen so that the particulate filter (PF) is regenerated possibly without any additional intervention into the engine operating parameters. The regeneration behavior of PF depends on the reaction rates of soot particles with oxidative reactants at exhaust gas temperatures. The reaction rates of soot particles from internal combustion engines (ICE) often are discussed in terms of order/disorder on the particle nanoscale, the concentration and kind of functional groups on the particle surfaces, and the content of (mostly polycyclic aromatic) hydrocarbons in the soot. In this work the reactivity of different kinds of soot (soot from flames, soot from ICE, carbon black) under oxidation conditions representative for PF regeneration is investigated. Soot reactivity is determined in dynamic Temperature Programmed Oxidation (TPO) experiments and the soot primary particle morphology and nanostructure is investigated by High-Resolution Transmission Electron Microscopy (HRTEM). An image analysis method based on known methods from the literature and improving some infirmities is used to evaluate morphology and nanostructural characteristics. From this, primary particle size distributions, length and separation distance distributions as well as tortuosities of fringes within the primary particle structures are obtained. Further, UV–visible spectroscopy and Raman scattering and other diagnostic techniques are used to study the properties connected to the reactivity of soot and to corroborate the experimental findings. It is found that nanostructural characteristics predominantly affect reactivity. Oxidation rates are derived from TPO and interpreted on a molecular basis from quantum chemistry calculations revealing a replication/activation oxidation mechanism.

Characterization of Various Biomass Feedstock Suitable for Small-Scale Energy Plants as Preliminary Activity of Biocheaper Project

The PRIN (Research Project with Relevant National Interest) project “Biocheaper—biomasses circular holistic economy approach to energy equipments” started in September 2019 and involves several universities: Palermo as the university coordinator, Perugia, Cassino, Enna, Pavia and Bolzano. The main goal of the project is to increase the energy efficiency and reduce the pollutants emissions in small-scale biomass plant for energy (heat and power) production. The project focuses on residual lignocellulosic feedstocks from the agriculture and forestry sector, from energy crops in marginal lands and residues from rivers maintenance. Starting from the selection and characterization of potential feedstocks, the project aims at developing some prototypes for retrofit applications in existing biomass boilers, like a mini-cyclone for the reduction of particulate emissions and an exhaust air-water condensing system for the recovery of water and the reuse in agriculture. This work presents the first results of the project, in particular regarding the selection and the chemical–physical characterization of different biomass, available in different zones of Italy; in particular the authors investigated cardoon chips, carthamus chips, olive and wine pruning, residues from rivers maintenance. Each biomass sample was characterized in terms of moisture content, ashes content, volatile substances, fixed carbon, low and high heating value, content of carbon, nitrogen, hydrogen and main metals.

Less CO2 and Fine Dust Emissions in Automotive

AbstractThere is increasing pressure on the automotive industry for further reduction of CO2 and particulate (PM10, PM2.5) emissions. One of the main issues is the fine dust resulting from the wear of the brake disc/brake pads, which is considered to be a major source of non‐exhaust traffic‐related emissions, particularly in urban locations. Carbide coatings are the state‐of‐art solution for controlling rotor wear. The challenge of cost‐effective serial production for automotive applications can be mastered by high power laser cladding.

Multiblend JET A‐1 in Practice: Results of an R&D Project on Synthetic Paraffinic Kerosenes

AbstractThe research and demonstration project, DEMO‐SPK, a model project under the German Mobility and Fuel Strategy (MFS), investigated the use of renewable kerosene at the Leipzig/Halle airport. Its primary goal was to examine and verify the behavior of blends consisting of several types of renewable kerosene and fossil JET A‐1, under the realistic supply conditions of a major airport. The project demonstrated that the supply chain for multiblend JET A‐1 was technically feasible and that the fuel could be used without requiring any changes in the normal operating procedures. The project also confirmed that the use of multiblend JET A‐1 resulted in a 30–60% reduction in particulate emissions for ground operations and a reduction in CO2 equivalents, compared with pure fossil JET A‐1.

Experimental Research of Diffusion Combustion and Emissions Characteristics Under Oxy-Fuel Combustion Mode

Abstract Internal combustion Rankine cycle (ICRC) concept implements oxy-fuel combustion, direct water injection (DWI), and waster heat recovery (WHR) into traditional Otto or diesel cycle to realize high thermal efficiency and low emission powertrain. In order to support ICRC realization, this paper is dedicated to investigate the feasibility of implementing oxy-fuel combustion into diffusion combustion which provides fundamental information for future compression ignition (CI)-ICRC engine. The prototype oxy-fuel diffusion combustion engine test bench is established based on a retrofitted diesel engine, and the O2/CO2 mixture intake system, high-pressure common rail fuel injection system, and high-performance electronic controller are designed and installed within engine test bench to investigate the combustion and emission characteristics under different intake oxygen fractions (OF), fuel injection durations, and fuel injection timing. The optimum intake OF and fuel injection strategies are acquired within the selected experimental conditions, a 41.1% brake thermal efficiency (BTE), and 1.2% coefficient of variation (CoV) is achieved utilizing 55% intake OF, 0.7 ms fuel injection duration and 352 °CA (after exchange top dead center (TDC)) fuel injection timing. The oxy-fuel diffusion combustion proved to be a feasible solution for simultaneously reduction in NOX and particulate emissions, and NOX emissions lower than 90 × 10−6 with particulate matters (PM) around 0.1 filter smoke number (FSN) is observed during engine bench testing. The result of this study provides fundamental information for future CI-ICRC prototype engine establishment and optimization, which also could be utilized as reference guidance for potential industrialization of internal combustion engine (ICE) with oxy-fuel combustion mode.

Experimental verification of fine particle emission reduction based on acoustic agglomeration for steel sintering flue gas

The sintering flue gas in steel production has the characteristics of large discharge capacity, fine size, high temperature, corrosion and fluctuation of working conditions, and is the primary control object of PM2.5 emission source. Traditional dust removal technologies and equipment are difficult to achieve efficient collection of fine particles. In order to quantitatively study the effect and regularity of high intensity sound waves on fine particles, the online acoustic agglomeration test system was built by using high-power pneumatic source and wave tube with abrupt section. The high intensity standing wave field of 140 to 150 dB was generated in the wide frequency range between 50 Hz and 2 kHz by the acoustic resonance synthesis, and interference from compressed airflow was avoided by the acoustic-flow separation module. Variation of the sintered flue gas PSD was obtained under different sound intensities and frequencies. Data analysis shows that the high concentration condition can greatly reduce the operation time and energy consumption. Under the action of high intensity acoustic waves with a fundamental sound pressure level of 87.3-161.8dB and duration of 3s, the measured PM2.5 removal efficiency is 16%-92%, and the optimal frequency is near 800Hz. This paper verifies the feasibility of acoustic agglomeration (AA) in the treatment of sintering flue gas, and provides a theoretical reference and technical basis for the development of PM2.5 real-time emission control device for steel production.

Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing.

Ultrafine particles and other hazardous materials are emitted during 3D printing, but the effect of temperature on such particles has not been studied systematically. The aim of this study was to evaluate the effect of temperature on the emission rate of particulate matter during fused deposition modeling (FDM) three-dimensional (3D) printing using different filament types. The number concentration of particles was measured with direct-reading instruments in an exposure chamber at various temperatures while using four filament materials during 3D printing. The temperature was increased from 185 to 290°C in 15°C increments, while incorporating the manufacturer-recommended operating conditions. The emission rate increased gradually as the temperature increased for all filament types, and temperature was the key factor affecting the emission rate after filament type. For all filaments, at the lowest operating temperature, the emission rate was 107 -109 particles/min, whereas the emission rate at the highest temperature was about 1011 particles/min, that is, 100-10000 times higher than the emission rate at the lowest temperature. To reduce particle emissions from 3D printing, we recommend printing at the lowest temperature possible or using low-emission materials.

Reductions of Particulate Matter Emissions of a Diesel Engine Fueled with Oxygenated and Emulsion Fuels

Reductions of Particulate Matter Emissions of a Diesel Engine Fueled with Oxygenated and Emulsion Fuels

Stack emissions and health risk integrated (SEHRI) model: a tool for stack emissions and health risk modeling

The quantitative assessment of health burden of coal power stack emissions is a vital step to frame effective policy measures to achieve emission reductions and corresponding health benefits. A plant-specific stack emission, dispersion, and health risk integrated (SEHRI) model has been proposed to estimate coal power stack emissions, resulting ambient air concentrations and associated health risks in the vicinity of a coal power plant. In this study, we have estimated the health benefits due to closure of Badarpur Thermal Power Station (BTPS), New Delhi. The SEHRI model has been applied to estimate decreased health risks due to particulates (PM2.5) and gaseous (SO2, NOx) stack emissions released from the plant. More than 1050 premature deaths are avoided and 526 life years are saved resulting from reduction in particulate and gaseous stack emissions, respectively, due to closure of the plant. It is expected that environmental engineers, scientists, and air quality managers would find the SEHRI model as a useful tool to study emissions and health impacts related to coal-based power plants and guide an effective control policy for air pollution abatement.

Influence of ESP collector configuration on reduction of particulate emissions from biomass combustion facility

Development of compact electrostatic precipitators (ESPs) for reduction of particulate emissions from small scale biomass combustion is an actual task. Particle mass collection efficiency of an ESP depends from combustion conditions, geometry of precipitator ionizer, collector stage configuration and ESP operation parameters. The investigation of the influence of collector stage configuration on particle mass collection efficiency of a pilot space charge ESP was in the focus of the study. It was shown that the use of tube collector with integrated grounded plates enhanced particle mass collection efficiency. The loading of plates with aerosol provoked particle re-entrainment and decreased long-term ESP mass collection efficiency. The use of grounded brush electrodes ensured effective reduction of particle emissions but resulted in increase of pressure drop in the precipitator. The optimization of cleaning intervals of the ionizer and collector stages increased particle mass collection efficiency. It was shown, that the integration of automatic systems for ionizer and collector cleaning into the space charge ESP enhanced precipitator long-term operation stability and ensured effective reduction of particulate emissions form small scale biomass combustion.

Diesel engine emissions: are they no longer tolerable?

Emissions from diesel engines contain several hundred chemical compounds, which are emitted partly as gas and partly as particles. The composition of diesel exhaust and its concentrations in air has changed significantly over time, to the extent that now there is a distinction between "traditional" and "new technology" diesel emissions. New technology diesel engines comply with emissions from EURO 3 vehicles and higher. Starting with EURO 5, a significant further reduction of particle emissions has been achieved by increased temperature, which, however, lead to increased emissions of NOx and exceeded the NO2 emission limit. To overcome this problem, some car manufacturers installed illegal software that detected the vehicle test bench operation, resulting in low emissions during the test cycle. Detection of such devices in 2015 led to the "Diesel scandal". In 2017 the worldwide harmonized light vehicles test procedure (WLTP) was introduced for new cars, which simulates emissions under different driving conditions. It became mandatory for certification of all new vehicles by September 2018. In addition, fleet CO2 emissions have been introduced for all cars, requiring that by 2020 95% of each manufacturer's passenger car must meet the CO2 emission target of 95mg/km, and by 2021 100% of the fleet. All these regulations significantly reduced the emissions of diesel- and gasoline-driven cars, which since the introduction of the EURO 6 regulation in 2014 are almost similar for both. Since the energy efficiency of diesel motors is up to 20% higher than that of gasoline-driven cars resulting in up to 20% lower CO2 emission, there is no reason to question the future use of diesel engines. These regulations apply for new cars. However, air concentrations at sampling points close to streets with high traffic still exceed the limit values especially for NO2. In several cities this led to restrictions for passenger cars of EURO 5 and below. Since concentrations close to streets are not relevant to evaluate the long-term exposure of the population, these measures are highly debatable.

Particle emissions of two unblended alternative jet fuels in a full scale jet engine

The emission of soot particles from aircraft jet engines is relevant due to their impact on contrail formation and local air quality in airport areas. The reduction of particle emission may be achieved by changes in jet engine design. This, however, will only affect new aircraft. Previous studies have shown that the use of alternative jet fuels feature a co-beneficial reduction of soot emission beside an improved carbon footprint. In the present study, a CFM56-5C4 engine was operated on a test rig with three different fuel types: one reference kerosene, a catalytic hydrothermolysis jet fuel (ReadiJet) and an unblended alcohol-to-jet (ATJ) fuel. Due to the absence of aromatics in the ATJ fuel, ASTM jet fuel requirements are not met, but the use of this fuel led to a reduction of 70% in particle mass compared to the reference fuel. The ReadiJet fuel has higher aromatic content, lower fuel hydrogen content and, thus, an increase in particle emission was observed. For the present engine, the highest soot reductions were observed at lower power settings. In accordance to previous studies, the soot emission showed a good correlation to the hydrogen content of the fuels and the emission reduction matches the estimations of the imFOX model. In order to compare test rig studies to field studies, transient processes must be considered because they govern take-off conditions. Four experiments with different transient thrust patterns were performed on the test rig with regular Jet A-1. If the thrust changes were not very rapid (e.g. 5 s to ~90% thrust) the results could be reproduced with a set of pseudo-stationary processes to a sufficient extend. This emphasizes the relevance of test-rig studies for real in-field measurements and local air quality studies.

NO2-Assisted Regeneration Performance Enhancement of Catalyzed Diesel Particulate Filters

Abstract Considering the stringent emission regulations all over the world, the reduction of particulate emissions from diesel engines is of major interest. To enhance passive regeneration performa...

Hybrid solar PV/PEM fuel Cell/Diesel Generator power system for cruise ship: A case study in Stockholm, Sweden

Optimal design and performance analysis of renewable energy system to serve the cruise ship main and auxiliary power in Stockholm, Sweden is presented in this paper. The goal is to integrate renewable energy systems in small and large ships for greener and sustainable marine transport. The power load for the cruise ship was determined, and modeling and simulation analysis was used to investigate the daily and annual performance of the power system architectures including the efficiency and capacity factors of the energy conversion systems. The total electrical power generated from the solar PV, PEM fuel cell, and Diesel generator; the cost of electricity; and the greenhouse gas and particulate matter PM emissions were determined. The proposed renewable energy system offers a good penetration of renewable energy system (13.83%), and greenhouse gas and particulate emissions reduction (9.84% emissions reduction compared to baseline system using Diesel engines). The integration of renewable and clean power systems such as solar PV and PEM fuel cell (high electrical efficiency) is very attractive solution for onboard ship power generation. They are economically viable (reduce the cost of Diesel fuel), cleaner than the conventional gas turbine and internal combustion engines and reduce the dependency on fossil fuel.

Experimental study on the emission characteristics of a non-road diesel engine equipped with different after-treatment devices.

A comparative experiment was conducted based on a non-road diesel engine to investigate the effects of two after-treatment devices on the engine's emission characteristics as well as their power and fuel consumption performances. The first after-treatment device is a combination of a diesel oxidation catalyst (DOC) and a catalytic diesel particulate filter (CDPF). The second device is a single CDPF-coated improved noble metal catalyst. Results showed that the two after-treatment devices had almost no effect on the power and fuel consumption performance. The gaseous and particulate emissions of the engine depended on the operation conditions including the speed and load. However, the dual DOC+CDPF system and the single CDPF reduced more than 81% of the carbon monoxide (CO) and 73% of the hydrocarbon (HC) emissions. Notably, the reduction efficiency by the single CDPF was higher than that of the DOC+CDPF system. In terms of the particulate emissions, both after-treatment devices achieved more than 96% reduction of the particle number (PN) and up to 88% reduction of the particulate mass (PM). Similarly, the single CDPF outperformed the dual DOC+CDPF system in reducing particle emissions. Although no changes occurred in the bimodal particle size distribution of the engine after the installation of the two after-treatment devices, they performed differently in reducing particles with different sizes. The particles reduction efficiency of the DOC+CDPF system was higher than that of the single CDPF for the particles smaller than 14.3nm, and this trend converted for particles larger than 14.3nm. Improving the noble metal catalyst load in the CDPF ensured a performance that rivaled the DOC+CDPF system. Apart from the NOx emissions, the installation of a single CDPF with an improved noble metal catalyst load can make the non-road diesel engine meet the limits of the China IV emission regulations.

Heat transfer studies for the design and optimisation of a distillation column to separate an automotive fuel

Methylal, an automotive fuel has been noticed as a diesel alteration additive with relatively high hydrogen-to-carbon ratio. Methylal is more volatile than diesel fuel but it is used as a diesel fuel component because of its 100% miscibility with diesel fuel. An attractive feature of methylal is the reduction of particulate emissions of toxic pollutants without affecting the energy density. Unfortunately, methylal is found to form a minimum boiling azeotrope with methanol whose separation by conventional distillation is impossible. Here, we have introduced an enhanced technique of pressure swing distillation which separates methylal and methanol by exploiting its pressure sensitivity. This work has addressed the design and optimisation of a pressure swing distillation column to separate the azeotropic mixture of methylal-methanol. A novel technique of pressure swing distillation has resulted in the production of pure methylal and pure methanol. The pressure in high pressure column of pressure swing distillation process has been optimised in such a way that there is minimization of overall cost of the process with maximization of product purities. Later on, a process intensification technique of heat integration has been developed which has resulted in 55.2% savings in energy by reducing the overall load of reboiler.

A novel electrical charging condensing heat exchanger for efficient particle emission reduction in small wood boilers

Small-scale biomass combustion is an important source of fine particles in ambient air, causing adverse health and environmental effects. Thus, there is a clear need to develop efficient and feasible flue gas cleaning technologies for small-scale combustion appliances. In this study a novel electrical charging condensing heat exchanger (eCHX) for combined fine particle removal and efficient heat recovery from flue gases was demonstrated in a small biomass-fired boiler. The method is based on the combination of a shielded corona charger and a condensing heat exchanger, where fine particles are removed by the electrophoretic, thermophoretic and diffusiophoretic forces. The eCHX was found to decrease >80% of fine particle mass (PM1) emissions and >40% of particle number emissions with simultaneous high thermal efficiency in the heat exchanger. The usage of the condensing heat exchanger without electrical charging resulted in 40% decrease in PM1 emissions when compared to the usage of a traditional tube heat exchanger. The advantage of the eCHX system is that it replaces the conventional heat exchanger in boilers, making it a compact and inexpensive solution, when compared to additional flue gas cleaning devices installed after the boiler.

Impact of ethanol blending into gasoline on aromatic compound evaporation and particle emissions from a gasoline direct injection engine

This study examined the interactions of ethanol with aromatic compounds on aromatic species evolution during gasoline evaporation and the consequent impacts on particle emissions from a single-cylinder, gasoline direct injection engine. From a chemical kinetic standpoint, the dilution of the aromatic species in gasoline by ethanol blending should reduce particle emissions because aromatics are the primary species that form particles during gasoline combustion. However, increased evaporative cooling from the ethanol and ethanol’s effect on when aromatics in the fuel droplet (or surface film or pool) evaporate can drive an increase in particle emissions. The objective of this study was to quantify these competing effects. The results show that a combination of ethanol’s increased evaporative cooling and impact on aromatic compound vapor-liquid equilibrium can extend droplet lifetime and cause aromatics to evaporate later in the droplet evaporation process than would be the case without ethanol. When fuels were burned in a direct-injection single-cylinder engine at high speed (2500 rpm) and relatively high load, ethanol blending caused an increase in particle emissions for fuels containing a low vapor pressure aromatic. At a lower speed (1500 rpm), no statistically significant increase in particle emissions was observed, likely because more time was available for evaporation and mixing to occur. In contrast, particle emissions from a fuel blended with a high vapor pressure aromatic were either insensitive to or reduced by ethanol blending, likewise to engine operating conditions. Current models for predicting particle emissions from gasoline engines, such as particulate matter index (PMI), generally lack variables for non-linear interactions between ethanol and gasoline hydrocarbons. To identify nonlinear interactions between predictor variables that might better explain the observed particle emissions, the least absolute shrinkage and selection operator (LASSO) regularized regression approach was employed. Among the predictor variables evaluated was the Yield Sooting Index (YSI) which is as an improved measure to quantify the aromatic’s chemical tendency to generate particle emissions. Following this analysis, two variables were selected based on their frequent appearance. The first was ethanol mole percent multiplied by aromatic mole percent divided by aromatic vapor pressure [(EtOH% * Aro%)/Aro VP@443 K]. The second was aromatic mole percent multiplied by aromatic YSI divided by aromatic molecular weight [(Aro% * Aro YSI)/Aro MW]. The results of linear regression including only these two combined explanatory variables achieved an r2 = 0.959, substantially improved over the PMI model (r2 = 0.688) and provides insight into how the PMI formalism might be modified to account for non-linear oxygenate-hydrocarbon coupling.

Developing of Particulate Matter Filtering System for Motorcycle by Reusing Engine Thermal Energy Emission

Vehicle particulate matter emission in terms of PM0.1 and PM2.5 have significantly increased their role in morbidity and mortality. In this research, we have developed a new method for particle matter filtering system to reduce the particulate concentration by optimizing the released combustion energy in the exhaust system. We reused the released energy to reduce particle emission by placing a metal net made of different materials such as aluminum, brass, stainless steel, and nickel in the compartment of the exhaust system. The system generated a radiation energy used to reduce particle concentration. The filter efficiency depended on the filter net material. The filter net made of aluminum gave the highest efficiency in reducing particle emissions. The efficiency reached 55% for the PM2.5 and 46% for PM0.1.

An Overview of the Influence of Biodiesel, Alcohols, and Various Oxygenated Additives on the Particulate Matter Emissions from Diesel Engines

Rising pollution levels resulting from vehicular emissions and the depletion of petroleum-based fuels have left mankind in pursuit of alternatives. There are stringent regulations around the world to control the particulate matter (PM) emissions from internal combustion engines. To this end, researchers have been exploring different measures to reduce PM emissions such as using modern combustion techniques, after-treatment systems such as diesel particulate filter (DPF) and gasoline particulate filter (GPF), and alternative fuels. Alternative fuels such as biodiesel (derived from edible, nonedible, and waste resources), alcohol fuels (ethanol, n-butanol, and n-pentanol), and fuel additives have been investigated over the last decade. PM characterization and toxicity analysis is still growing as researchers are developing methodologies to reduce particle emissions using various approaches such as fuel modification and after-treatment devices. To address these aspects, this review paper studies the PM characteristics, health issues, PM physical and chemical properties, and the effect of alternative fuels such as biodiesel, alcohol fuels, and oxygenated additives on PM emissions from diesel engines. In addition, the correlation between physical and chemical properties of alternate fuels and the characteristics of PM emissions is explored.