Reduction In PM Emissions Research Articles

Dynamic evolution of particulate and gaseous emissions for typical residential coal combustion

Residential coal combustion still accounts for half of the heating energy consumption in many developing countries. The dynamic variation during the combustion process importantly determines the combustion facility design and appropriate air quality assessment, which was omitted in conventional studies. This study investigated the emissions of particulate and gaseous pollutants during the combustion process for typical coal types using online monitoring. During the first pyrolysis stage with temperature climbing, the organic aerosols (OA) and gases reached peak concentration. The second fierce combustion stage had the highest temperature and produced the highest cumulative emissions, particularly a substantial amount of black carbon for coals with higher volatile content. Using higher-quality coals will undoubtedly reduce PM emissions, by a factor of 10 from bituminous to anthracite coal. However, more ultrafine particles (d < 0.1 μm) from cleaner coal may pose additional health risks. Anthracite and honeycomb coal had approximately twice the energy content and emitted more CO2 per unit mass of fuel and had more persistent SO2 emissions throughout the burnout stage. The oxygenation of OA and organic gases remained increased during combustion, suggesting the pyrolysis products underwent oxidation before being emitted. The investigation of the coal combustion process suggests the importance of reducing volatiles to control PM emissions, but the potential negative synergistic effects between PM reduction and increased carbon emissions should also be considered.

Effects of particulate matter (PM2.5) concentration and components on mortality in chronic kidney disease patients: a nationwide spatial–temporal analysis

Chronic kidney disease (CKD) is a major global public health issue and the leading cause of death in Thailand. This study investigated the spatial–temporal association between PM2.5 and its components (organic carbon, black carbon, dust, sulfate, and sea salt) and CKD mortality in Thailand from 2012 to 2021. The Modern-Era Retrospective analysis for Research and Application version 2 (MERRA-2), a NASA atmospheric satellite model, was assessed for the temporal data of PM2.5 concentration and aerosol components. Spatial resources of 77 provinces were integrated using the Geographical Information System (GIS). Multivariate Poisson regression and Bayesian inference analyses were conducted to explore the effects of PM2.5 on CKD mortality across the provinces. Our analysis included 718,686 CKD-related deaths, resulting in a mortality rate of 1107 cases per 100,000 population where was the highest rate in Northeast region. The average age of the deceased was 72.43 ± 13.10 years, with males comprising 50.46% of the cases. Adjusting for age, sex, underlying diseases, co-morbidities, CKD complications, replacement therapy, population density, and income, each 1 µg/m3 increase in PM2.5, black carbon, dust, sulfate, and organic carbon was significantly associated with increased CKD mortality across 77 provinces. Incidence rate ratios were 1.04 (95% CI 1.03–1.04) for PM2.5, 1.11 (95% CI 1.10–1.13) for black carbon, 1.24 (95% CI 1.22–1.25) for dust, 1.16 (95% CI 1.16–1.17) for sulfate, and 1.05 (95% CI 1.04–1.05) for organic carbon. These findings emphasize the significant impact of PM2.5 on CKD mortality and underscore the need for strategies to reduce PM emissions and manage CKD co-morbidities effectively.

Comparative analysis of energy, exergy, emission, and sustainability aspects of third generation microalgae biodiesels in a diesel engine

Third-generation biodiesel produced from various microalgae species is being researched for its production, conversion, compatibility, sustainability, and environment-friendly behaviour for the diesel engine as a replacement of conventional diesel fuel. The present work is conducted with the objective of analysing a clean, green, and sustainable microalgae biodiesel for energy, exergy, emission, and sustainability assessment in a diesel engine system, along with the evaluation of air quality in terms of emission analysis for assessing its impact on climate. The fuel samples from diesel and the three microalgae species, viz., Chlorella emersonii, Euglena sanguinea, and Spirulina, are designated as DF100, CE100, ES100, and SP100, respectively. The engine behaviour is assessed and compared at 1500 rpm under 17.5 compression ratio with 25–100 % engine load. DF100 achieves the maximum energy and energy efficiency of 32.76 % and 30.74 %, respectively, and a varied range of 27.32–30.37 % and 25.28–28.10 % with microalgae biodiesels. The air quality is improved with the reduction of PM emissions by 15.82–27.09 % at the cost of improved nitrogen oxide (NOx) emissions by 11.03–15.55 %. The sustainability index is highest for DF100 (1.247–1.444), and among biodiesel fuel samples, it is highest for SP100 (1.233–1.391) at all engine loads. These results point to the possibility of microalgae-derived biodiesel blends as feasible diesel fuel substitutes, providing environmentally friendly and effective solutions for internal combustion engines.

Decoupling dynamics: Evaluating the relationship between ship emissions and socioeconomic progress in the Yangtze River Basin from 2007 to 2022

To investigate the decoupling relationship between inland ship emissions and regional socioeconomic development in the Yangtze River Basin, this study constructed an emissions inventory for inland ships from 2007 to 2022, based on inland shipping freight statistics and ship carbon pollution emission intensity. Additionally, the Petri-Tapio decoupling model was employed to analyze the relationship between ship carbon pollution emissions and per capita GDP. The study concluded that CO2 emissions from inland ships in the Yangtze River Basin increased from 2.418 million tons in 2007 to 10.801 million tons in 2022. In 2021, the emissions of NOx and SOx from inland ships in the Yangtze River Basin accounted for 2.27% and 0.0021%, respectively, of China's anthropogenic emissions. Despite a year-on-year increasing trend in ship emissions within the basin, significant reductions in PM and SO2 emissions were observed post-2018 due to the implementation of emission reduction policies. Furthermore, we found that economically developed areas such as Shanghai, Jiangsu, and Zhejiang had higher emissions compared to other regions, with regional ship emissions positively correlating with the level of economic activity. Decoupling analysis results indicated that most provinces in the Yangtze River Basin have not effectively decoupled ship carbon pollution emissions from GDP growth. The findings of this study provide support for the Chinese government to formulate stricter ship emission control policies while promoting the growth of the Yangtze River shipping economy.

Introduction of ERAC (Environmental Risk Assessment and Control) Frame Work in Manufacturing to Enhance Sustainability

This paper introduces the Environmental Risk Assessment and Control (ERAC) framework as a comprehensive approach to managing environmental impacts throughout the lifecycle of product manufacturing processes. Drawing from a detailed case study conducted at a fiber cement manufacturing plant in Odisha, India, the study identifies environmental risks across various phases including raw material extraction, manufacturing processes, and product disposal. ERAC involves five key components: identification of environmental risks, rigorous risk assessment using tools such as environmental modeling and life cycle assessment, formulation of tailored control measures, implementation with robust monitoring, and continuous improvement. The case study demonstrates significant improvements in environmental performance indicators post-implementation, highlighting reductions in specific PM emissions, carbon footprint, waste generation, and energy consumption, as well as enhancements in productivity and workplace safety. The findings underscore ERAC's effectiveness in promoting sustainable manufacturing practices and environmental stewardship.

Characteristics of particulate matter from asphalt pavement and tire of a moving bus through driving tests in city road and proving ground

Non-exhaust PM emissions from vehicles in real road have been conducted, but heavy vehicles have rarely been tested. In this study, PM2.5 and PM10 samples were directly collected from a tire of a moving bus and the composition was analyzed to investigate the sources of PM emissions. Driving tests were conducted at a proving ground (PG) and a city road (CR). PM2.5 emissions considerably increased when the lateral force of the tire increased and the vehicle accelerated. The PM emission rate was higher in the PG test than in the CR test because of the harsher driving conditions at PG. The emission rates of PM10 in the PG and CR tests were higher than those of PM2.5 by approximately 6 and 11 times, respectively. In the PG and CR tests, the proportions of tire wear particles (TWPs) were 4.9% and 2.1% in the PM2.5 samples, and 6.8% and 8.2% in the PM10 samples, respectively. Furthermore, TWPs with PM (TWPPM) were generated by other sources: secondary production of TWPPM by fragmentation of TWPs and resuspension of TWPPM on the road. The contributions of other sources to TWP2.5 generation were at least 6% and 57% in the PG and CR tests, respectively, whereas that to TWP10 generation was at least 3.5% in the CR test. Iron derived from brake abrasion and mineral particles was observed in the PM samples, and the Fe concentrations were higher in the PM10 samples than in the PM2.5 samples by over 9 and 18 times for the PG and CR tests, respectively. Sulfur sources, such as TWPs, exhaust gas, and bitumen, were observed in the PM samples. Based on our findings, we recommend that road wear particles should be removed from roads to reduce PM emissions upon driving.

Experimental investigation of low temperature combustion in a diesel engine depending on injection advance and injection pressure

In this study, the performance parameters and emissions of a pre-mixed charge compression ignition were investigated under different injection pressures and injection advances. After the peak engine power was reached, reasonable decreases occurred in brake mean effective pressure at certain injection advances with the increase of injection advance, and dramatic decreases observed when interval was so exceeded. In addition mean indicated pressure and peak in-cylinder pressure were investigated. Considering the emissions, dramatic increases were observed in CO and total hydrocarbon, depending on the increase in the low temperature combustion regime. The NOx started a rapid downward trend after a certain injection advance value in the experimental region, but this effect did not occur at the de?sired level for specific NOx. It was observed that the NO2 to NOx ratio increased as the pre-mixed charge compression ignition became dominant and NO2 production increased among the total NOx. In the operating region where the low temperature combustion regime was dominant, the targeted reduction in NOx and particulate matter emissions was observed, but the desired reduction in specific emissions did not occur. In the low temperature combustion region, the combustion process was prolonged, initially reasonable changes occurred at performance parameters, but unacceptable results were observed at high injection pressures with excessive injection advances.

Engine preheating under real-world subfreezing conditions provides less than expected benefits to vehicle fuel economy and emission reduction for light-duty vehicles

Six light-duty vehicles, both gasoline- and diesel-fueled, were driven a prescribed 13.8 km route in a real-world low-traffic environment under Finnish subfreezing winter conditions (−28 ... −10 °C). Cold starts, hot starts, and starts with different preheating strategies were used. Fuel consumption and emissions of particles and nitrogen oxides (NOx) were examined by a chasing method with a mobile laboratory. Both electric preheaters (0.3–1.2 kW) and fuel-operated auxiliary heaters (5 kW) were used in the experiments where a cold engine was preheated before starting. While most vehicles showed potential for reducing fuel consumption and emissions of particles (PM), black carbon (BC), and NOx during hot starts compared to subfreezing-cold starts, the benefits of preheating were relatively small and limited to only a few vehicles. The fuel consumption for the 13.8 km drive decreased less than 4% with one gasoline vehicle and one diesel vehicle by preheating. These two vehicles are both equipped with a fuel-operated auxiliary heater, and taking the fuel consumption of the heater during preheating into account leads to about 30% higher total fuel consumption, canceling the preheating benefit out. These two vehicles also showed the largest reductions in PM, BC, and NOx emissions achieved with preheating, e.g., the PM emission reductions being 72% (the gasoline vehicle) and 24% (the diesel vehicle). Whereas the NOx emission reduction for this gasoline vehicle was 41% when considering only the drive, it decreases to 15% when the NOx emissions from the auxiliary heater during preheating are also taken into account. High particle number (PN) emissions from all vehicles and NOx emissions from the diesel vehicles were detected. The PN emissions of particles larger than 23 nm were up to 2 orders of magnitude higher and the NOx emissions up to a factor of 21 higher than the corresponding limits in the European regulations for type-approval of new vehicles. The PN emissions did not depend on the start types; thus, no benefits to reduce them with preheating were detected. The limit-exceeding PN emissions are partially explained with the used measurement method for PN taking both nonvolatile and semivolatile particles into account, whereas the regulations take only the nonvolatile particles into account. The PM emissions were also observed to consist mostly of semivolatile material in most of the cases, organics being the main component of the semivolatile material.

Soot particles undergo in-cylinder oxidation again via EGR recirculated gas: Analysis of exhaust soot particle characteristics

Exhaust gas recirculation (EGR) is one of the effective methods to control NOx emission from diesel engine. The present study focused on the amount of soot particles that are back into the engine cylinder via EGR recirculated gas, to explore its influence mechanism on exhaust soot particle characteristics. A DPF (diesel particulate filter) was integrated in EGR loop, which was employed to remove recirculated soot particles and reduce PM emissions. A comprehensive set of experimental techniques were used to characterize the morphology, nanostructure, surface functional groups and oxidation behaviors of soot particles. Results revealed that when soot particles underwent in-cylinder oxidation again via EGR recirculated gas, exhaust soot particles had smaller primary particle size (dp), longer fringe length (La), smaller separation distance (Ds) and tortuosity (Tf), as well as lower relative amount of aliphatic C–H group and oxidation reactivity. Due to higher graphitization degree of recirculated soot particles, the internal burning was conducted earlier during oxidation processes, which resulted in hollow structure at 50% and 75% burn-off stages.

Optical and Numerical Investigations on Combustion and OH Radical Behavior Inside an Optical Engine Operating in LTC Combustion Mode

Low Temperature Combustion (LTC) is a relevant process for internal combustion engines (ICE). This combustion mode is based on premixed fuel/air and fuel lean in-cylinder mixture allowing reduction in NOx and PM emissions while maintaining higher thermal efficiency. In order to investigate the effect of engine operating conditions on the behavior of LTC mode, including OH radical evolution, optical measurements and numerical simulations were performed on a transparent CR diesel engine. The homogeneity of the engine charge was obtained by using very early injection timings. In this study, varying injection strategies were investigated for different engine speeds. In parallel to the experimentation, simulations of LTC mode for the same experimental operations were carried out. The model used in this study is based on a stochastic reactor model. This model includes a turbulence (k-ε) model based on a zero-dimensional energy cascade to calculate the turbulent time scale during the cycle. On the other hand, due to the stochastic approach and to reduce initial heterogeneities of the mixture, a confidence parameter was introduced in the global model to consider the real variation ranges of engine. This latter was modeled as a function of the Reynolds number allowing to initiate heterogeneities of temperature and of species mass. OH radicals were estimated with high spatial and temporal resolution using chemiluminescence measurements. Simulated in-cylinder pressure and the OH radical rate were compared to the experimental data. A good agreement was observed in terms of in-cylinder pressure trace and ignition delay times, meaning that the confidence coefficient model is accurate to describe the initial heterogeneities of the mixture. The simulated OH rate profile has the same shape as the measured OH trace and the main ignition occurs at the same time. This study corroborates that the OH radical is an appropriate tool to identify combustion stages.

Combustion, performance and emission analyses of a CI engine operating with renewable diesel fuels (HVO/FARNESANE) under dual-fuel mode through hydrogen port injection

The use of hydrogen in internal combustion engines is pointed out as an alternative to reduce greenhouse gas emissions. In applications that require high levels of torque and low engine speeds, compression ignition (CI) engines are more appropriate. However, because of the high auto-ignition temperature of hydrogen, its use in these engine types is more suitable when the dual-fuel concept is applied. This study comprehensively investigates, through experimental techniques, the use of hydrogen port-injection in a four-stroke single-cylinder CI engine operating with the renewable diesel-like fuels hydrotreated vegetable oil (HVO) and farnesane, in comparison to fossil diesel dual-fuel operation. In this sense, the present work aims to fill a gap in the literature by performing a novel analysis of dual-fuel operation with hydrogen, considering different substitution fractions, and using groundbreaking biofuels, such as HVO and farnesane. The results showed that in-cylinder pressure and temperature were increased with H2 enrichment for every pilot fuel, but green diesel fuels presented lower values than those for diesel operation. Furthermore, hydrogen port injection slightly delayed the start of combustion and increased the ignition delay, but a reduction in both premixed and diffusion combustion duration was observed. Reductions in PM, CO, and CO2 emissions were reported during H2 addition for every pilot fuel, while increased NOx was observed. Despite this increase, both HVO and farnesane decreased the emissions of this pollutant in single and dual-fuel operations, compared with fossil diesel. In addition, both renewable diesel fuels presented higher BTE than diesel for every studied H2 mass flow.

Study on Braking Energy Recovery Control Strategy for Four-Axle Battery Electric Heavy-Duty Trucks

Regenerative braking can extend the driving range and reduce PM emissions from abrasion for battery electric heavy-duty trucks (BETs). The composite braking control strategy including torque distribution and dynamic coordinated control for the four-axle BET equipped with the electromechanical braking system is studied. A segmented torque distribution strategy is proposed to maximize energy recovery while ensuring braking stability. The simulation results reveal that the strategy shows better comprehensive braking performance than the two benchmark strategies, and the energy recovery rate in different load states under CHTC-D is above 40%. The proposed coordinated control strategy takes advantage of regenerative braking’s rapid response and precise control to compensate for torque deviations caused by the hysteresis of friction braking. For two common braking mode transition conditions, regenerative braking torque correction and advance of the mode switching timing are adopted to enable the motor to obtain the torque compensation ability. This method leads to a slight loss of braking energy, and the maximum torque deviation during the mode switching process is suppressed to less than 1.4 kN·m, and the jerk and braking distance is reduced accordingly, which is of great importance in improving driving comfort and braking safety.

Molecular characteristics of ambient organic aerosols in Shanghai winter before and after the COVID-19 outbreak

During the global pandemic of COVID-19, the world adopted different strategies to avoid the human and economic loss, and so does China. The reduction of human activities during this time period caused reduction in PM emissions. This study adopted a HPLC-Q-TOF-MS to compare the chemical compositions of ambient aerosol samples collected in Shanghai winter before (2018, 2019) and after (2021) the COVID-19 outbreak. The identified compositions were classified into subgroups of CHO, CHN, CHON, CHONS, CHOS and CHN compounds. Results showed that CHO compounds and CHON compounds were dominating the organic compounds in ESI− and ESI+, respectively. The average percentages of CHO− compounds were 57.97 % in 2018, 58.98 % in 2019, and 43.93 % in 2021, respectively. The average percentages of CHON+ compounds were 52.74 % in 2018, 50.34 % in 2019, and 52.02 % in 2021, respectively. The proportion of aliphatic compounds increased gradually during the three years, especially in 2021, indicating that CHO compounds were less affected by aromatic precursors after the COVID-19 outbreak. The contribution of anthropogenic emissions in Shanghai was weakened compared with the previous years. In addition, there was an enhanced emission source containing hydroxyl for CHOS compound formation in 2021. The variations of atmospheric oxidation degree among the three years were not significant.

Assessing Environmental Mitigation Strategies in Controlled Cage-Free Aviary Housing Systems: Effect on Air Quality and Bioaerosols

Highlights Three mitigation strategies were tested in experimental chambers fitted as small-scale aviaries. Particle monitor and high-flow air samplers were used to sample airborne dust (PM) and bioaerosols. Oil emulsion sprinkling on the litter surface of aviaries was effective in reducing PM emissions in experimental chambers. Abstract. Alternative housing systems for laying hens are gradually replacing battery cages. Though these systems provide more space per animal and enrichments, higher concentrations of ammonia and airborne dust have been reported in those environments. In this project, three environmental control strategies and a control condition were tested in twelve experimental chambers fitted as small-scale aviaries. The experiment was conducted during three periods spanning 18 weeks, during which PM and bioaerosols were sampled in each chamber in three separate sampling campaigns. Emissions of PM, culturable bacteria and molds, total bacteria, Penicillium, and Aspergillus molds and selected fecal indicators (Campylobacter coli, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Enterococcus spp., Salmonella spp.) were assessed in each experimental chamber. Strategies that included oil emulsion sprinkling on litter surface were effective at reducing PM emissions, while no significant effect (p &amp;gt; 0.05) was observed on ammonia emissions, and the effect on bioaerosol was variable under the evaluated conditions. Keywords: Airborne dust, Aviaries, Bioaerosol, Laying hen alternative housing, Mitigation.

Simulation Study on NO and PM Emission Reduction of Engine by Coupled Miller Cycle with Butanol Blending

Trade-off effect of engine emission, that is, NO emission reduction will lead to increase of PM emission. In order to alleviate the contradiction between NO and PM emission, coupling miller cycle with burning butanol was proposed. The simulation model was built by using AVL-FIRE software. The coupling scheme is optimized by changing intake pressure with power performance as constraint condition and emission reduction as evaluation index. Simulation results show that the mixing ratio B30 combined with miller degree M20 scheme matches the intake pressure 0.213MPa well. On a constant power basis, the simultaneous reduction of NO and PM is achieved.

Analysis of The Influences of Biodiesel On Performance and Emissions of a Diesel Engine

Biodiesel remains an alternative fuel of interest for use in diesel engines. A common characteristic of biodiesel relative to petroleum diesel, is a lowered heating value (or energy content of the fuel). This review paper discusses the characteristics of biodiesel that has a great influenceon the performance and emission of diesel engine. A lower heating value of the fuel, assuming all other parameters are equal would result in decreased engine torque. Since engine torque is often user-demanded, the lower heating value of the fuel generally translates into increased brake specific fuel consumption.The biodiesel from edible oils isnon-toxic, biodegradable and renewable alternate fuel that can be used as a substitute for diesel in diesel engines. There is some indication that the use of biodiesel fuel can degrade diesel engine oil performance to such an extent that shortening of oil drain intervals is required. Oil, which is fuel-diluted with biodiesel, which is also known to contain unsaturated hydrocarbon bonds would be expected to be more prone to oxidation. Besides, the use of biodiesel leads to the substantial reduction in PM, HC and CO emissions accompanying with the imperceptible power loss, the increase in fuel consumption and the increase in NOx emission on conventional diesel engines with no or fewer modification. Plus, it favors to reduce carbon deposit and wear of the key engine parts. Therefore, the blends of biodiesel, with small content in place of petroleum diesel, can help in controlling air pollution and easing the pressure on scarce resources without significantly sacrificing engine power and economy. However, many further researches on optimization and modification of engine, low temperature performances of engine, new instrumentation, methodology for measurements and etc., should be performed when petroleum diesel is substituted completely by biodiesel. In this study, reports about biodiesel engine performances and emissions, published by highly rated journals in scientific indexes were cited preferentially since the year 2000. From these reports, the effect of biodiesel on engine power, economy, durability, emissions including regulated and non-regulated emissions and the corresponding effect factors are surveyed and analyzed in detail.

Effects of Oxymethylene Ether in a Commercial Diesel Engine

Oxymethylen Ether (OME) is a promising alternative fuel for diesel engines. It can be produced sustainably, and its combustion is clean and efficient. This study investigates the effects of different OME3-5 mixtures on emissions and combustion. The measurements were done on a four-cylinder common rail commercial diesel engine equipped with an exhaust gas recirculation system (EGR). Five different blends of OME3-5 and B7 diesel were applied with 0, 7, 15, 25 and 45 vol% OME3-5 content at four loads. The NOx–PM trade-off was investigated at 11 EGR rates for each mixture at each load. Increasing OME3-5 mixing ratio reduced the PM emission, improved the NOx–PM trade-off, and increased the brake thermal efficiency. The maximum achieved PM emission reduction was 86.8% for high loads. However, NOx emission increased, and also low heat capacity and viscosity can be a problem for real applications

Optimization of aromatic species in formulated fuel for simultaneous reduction of PM and NOx emissions from combustion engines

A new integrated experimental technique is used to design viable and cleaner fuel blends with selective fuel contents. In diesel combustion engines, higher PM and NOx emissions are the major pollutants that need to be addressed simultaneously. The selection of fuel components based on emission formation tendencies is a promising approach to reduce these emissions. Aromatics highly affects the emission in diesel-fueled engines, especially PM. The present study provides a comprehensive knowledge database on a range of aromatics that need to be removed from the fuel during production processes for better performance and lower engine emissions. To investigate the effects of aromatic species and content on emissions, 16 different aromatic species were tested in 8, 13, and 18% volumetric concentrations in an alkane-based fuel. The experiments were conducted at 850 and 1500 rpm engine speed conditions. The ranking system was developed to rank the aromatics based on their overall performance in terms of PM and NOx emissions. The blend with 8% tert-butylbenzene showed a maximum PM reduction of 73.1% due to higher hydrogen atoms relative to carbon. Better atomization with higher volatility due to the lower density of this blend promoted oxidation rather than pyrolysis. NOx emissions were found to be maximum of 10.4% lower with 8% o-Xylene in the blend due to lower heat release rate. Improved heat distribution over the premixed and diffusion combustion modes due to this blend's optimum physical properties helped reduce the in-cylinder temperature. A consideration of equal weightage to NOx and PM emissions, 8% tert-butylbenzene is the most promising aromatic candidate for cleaner fuel production.

Spatially selective dilution - A novel approach for heat release control in continuous combustion

To support the ongoing energy transition and minimize the environmental footprint of combustion related technologies, the paper presents a novel approach for combustion control in gas turbines and burners. It relies on spatially targeted injection of inert components in the spray core where existent concepts fail to deliver the desired dilution rate and are unable to fully govern the spatial distribution of heat release rates. Combustion process control is thus possible by actively adjusting the composition and mass flow of spatially selective introduction of inert species in the spray, optionally combined with classic, external exhaust gas recirculation, leading to an ultimate fuel-flexible concept which is capable of adjustments to heterogeneous fuels, their reactivity and physical properties. The proof of concept is demonstrated in a gas turbine combustion chamber first by investigating the isolated effects of spatially selective injection of inert species, its comparison to external exhaust gas recirculation and a combination of both. The results confirm the superiority of the approach as spatially selective mixture inertization is capable of 7% reduction of NO emissions with merely 3% increase of CO emissions and even 9% reduction of PM emissions. Furthermore, the concept proved transferrable together with all its benefits to combustion cycles with external exhaust gas recirculation. In this case, the 63% reduction of NO emissions with no observed CO penalty is possible. Simultaneous exploitation of spatially selective inertization, as well as external exhaust gas recirculation forms a fully controllable concept - spatially selective dilution control (SSDC), which enables extensive adjustability of dilution rates throughout the spray core and primary zone of combustion chamber. Compared to baseline case, such approach was proved to simultaneously reduce CO, NO and PM emissions normalized to fuel thermal power for 39%, 63% and 91%, respectively. The confirmation of applicability of the novel approach and its potential to influence the local conditions is opening a series of possible uses, either as an original design feature for future fuel-flexible systems or as a retrofit approach in existent combustion systems.

Air Quality Status in Konya City Centre, Konya, Turkey during Pandemic Covid-19

Abstract High developed industry regions, provincial centers with a heavy traffic and dense populations with cold winters, using low-quality fossil fuel consumption have an effect on quality of life especially for people with respiratory diseases. The air quality data gathered from air monitoring stations for the City Center of Konya, Turkey were analysed statistically during the period when curfew due to the Covid-19 pandemic in 2020. The restrictions that cause the reduction of vehicle exhaust emissions, which are important factors in the formation of some air pollutants, are thought to be effective in improving the air quality as well as meteorological conditions are effective on the days when the air quality is analysed. It is thought that the reduction in HC, NOx, CO and PM emissions, which can be evaluated as exhaust emissions, will be an effective factor due to the restrictions of Covid-19 pandemic. Comparing between the 2019 and 2020 MCO data, we identified that most of the gases decreased with NO2 (-24 µg/m3), SO2 (-24 µg/m3), CO (-37 µg/m3) and an increment of O3 of +50 µg/m3 which indicates that the MCO and restricted of movement were give an impact to air quality levels in Konya City. The increase in O3 values were found by the existing of the sun rays in the atmosphere with the formation of O3 during the clean air period.