Optimization of Microgrid Using Quantum Inspired Evolutionary Algorithm

This paper presents a generalized formulation for determining the optimal operating strategy and cost optimization scheme as well as reducing the emissions of a MicroGrid (MG). Multiobjective (MO) optimization is applied to the environmental economic problem of the MG. The proposed problem is formulated as a nonlinear constrained MO optimization problem Prior to the optimization, system model components taken from real manufactural data are constructed. The model takes into consideration the operation and maintenance costs as well as the reduction in emissions of NOx, SO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> . The MG considered in this paper consists of a wind turbine, a micro turbine, a diesel generator, a photovoltaic array, a fuel cell, and a battery storage. The optimization is aimed at minimizing the cost function of the system while constraining it to meet the costumer demand and safety of the system. The results demonstrate the efficiency of the proposed approach to satisfy the load and to reduce the cost and the emissions in one single run.

The computational fluid dynamical software AVL-FIRE code was used for investigating the impact of multiply injection strategies and spray included angles on combustion and emissions in a marine diesel engine. The fuel injection parameters of spray included angle and pilot injection timing with pilot-main injection, as well as post injection ratio and post injection duration angle with pilot-main-post injection, were all investigated and optimized. The results indicate that retarding pilot injection timing with pilot-main injection declines high temperature region, resulting in a notable reduction in NOx emissions. Since fuel evaporation and burn are hampered by long spray penetration due to low temperature and pressure with pilot injection, a suitable spray included angle are used to offer more efficient air-fuel mixing process. A wider spray included angle simultaneously reduces soot emission and indicated specific fuel consumption (ISFC). Post injection fuel exerts impact on combustion process by causing a great disturbance to flow field during post combustion. Increasing post injection ratio from 4% to 10% at a small post injection duration angle great emission performance is achieved by simultaneous reduction in NOx and soot emissions while only using a slight consumption of ISFC. To summarize, the defeat of traditional NOx-soot trade-off occurs as both NOx and soot emissions are decreased with optimized multiple injection strategy and spray included angle. Particularly, there are respectively four cases with pilot-main injection and two cases with pilot-main-post injection, that achieve simultaneous reduction in NOx emissions, soot emission, and ISFC, compared to the prototype.

Simultaneous reduction of NOx emission and SOx emission aided by improved efficiency of a Once-Through Benson Type Coal Boiler

Atmospheric distribution of photochemical oxidants has been a subject of interest and concern not only because of their deleterious effects on human health and vegetation but also because of their crucial role in determining the chemical composition of the atmosphere. Several important issues related to the distribution and production of photochemical species are examined through an analysis of results obtained from applications of a comprehensive three‐dimensional regional scale photochemical model over the Northeast United States. The Regional Oxidant Model (ROM) is used to simulate the response of various photochemical species to specific anthropogenic emission strategies involving NOx, and hydrocarbon reductions for an episodic period during July 1988. Domain and temporal averages of predicted concentrations are examined for various species. Their relative influence on oxidant chemistry over the modeled domain is investigated. Further, spatial distributions of O3 with respect to those of NOx, NOy, and hydrocarbons over the modeled domain are examined and the variations in O3 levels for different chemical regimes classified by characteristic NOx/reactive organic gases and NOx/NOy ratios are investigated. Temporal trends in domain‐averaged concentrations indicate that the model replicates the expected diurnal trends in species concentrations. The relative benefits of reductions in NOx and hydrocarbon emissions on predicted O3 levels are also examined. In general, for this modeled domain, reductions in NOx emissions with or without reductions in hydrocarbon emissions have more impact on reducing predicted O3 levels compared to reductions only in hydrocarbon emissions.

New-particle nucleation within coal-fired power-plant plumes can have large effects on particle number concentrations, particularly near source regions, with implications for human health and climate. In order to resolve the formation and growth of particles in these plumes, we have integrated TwO-Moment Aerosol Sectional (TOMAS) microphysics in the System for Atmospheric Modelling (SAM), a large-eddy simulation/cloud-resolving model (LES/CRM). We have evaluated this model against aircraft observations for three case studies, and the model reproduces well the major features of each case. Using this model, we have shown that meteorology and background aerosol concentrations can have strong effects on new-particle formation and growth in coal-fired power-plant plumes, even if emissions are held constant. We subsequently used the model to evaluate the effects of SO2 and NOx pollution controls on newparticle formation in coal-fired power-plant plumes. We found that strong reductions in NOx emissions without concurrent reductions in SO2 emissions may increase new-particle formation, due to increases in OH formation within the plume. We predicted the change in new-particle formation due to changes in emissions between 1997 and 2010 for 330 coal-fired power plants in the US, and we found a median decrease of 19% in new-particle formation. However, the magnitude and sign of the aerosol changes depend greatly on the relative reductions in NOx and SO2 emissions in each plant. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed, however, to better quantify these effects.

Fluxes of nitrogen oxides (NOx = NO + NO2) and carbon dioxide (CO2) were measured using eddy covariance at the BT Tower in central London during the coronavirus pandemic. Comparing fluxes to those measured in 2017 prior to the pandemic restrictions and the introduction of the Ultra-Low Emissions Zone (ULEZ) highlighted a 75 % reduction in NOx emissions between the two periods but only a 20 % reduction in CO2 emissions and a 32 % reduction in traffic load. Use of a footprint model and the London Atmospheric Emissions Inventory (LAEI) identified transport and heat and power generation to be the two dominant sources of NOx and CO2 but with significantly different relative contributions for each species. Application of external constraints on NOx and CO2 emissions allowed the reductions in the different sources to be untangled identifying that transport NOx emissions had reduced by > 75 % since 2017. This was attributed in part to the success of air quality policy in central London, but crucially due to the substantial reduction in congestion that resulted from pandemic reduced mobility. Spatial mapping of the fluxes suggests that central London was dominated by point source heat and power generation emissions during the period of reduced mobility. This will have important implications on future air quality policy for NO2 which until now, has been primarily focused on the emissions from diesel exhausts.

NOx and PM emissions reduction on an automotive HSDI Diesel engine with water-in-diesel emulsion and EGR: An experimental study

<strong class="journal-contentHeaderColor">Abstract.</strong> The reduction of fine particles (PM_2.5) and reactive N (N_r) and S (S_r) species is a key objective for air pollution control policies because of their major adverse effects on human health, ecosystem diversity, and climate. The sensitivity of global and regional N_r, S_r, and PM_2.5 to 20 % and 40 % individual and collective reductions in anthropogenic emissions of NH₃, NO_x, and SO_x (with respect to a 2015 baseline) is investigated using the EMEP MSC-W atmospheric chemistry transport model with WRF meteorology. Regional comparisons reveal that the individual emissions reduction has multiple co-benefits and small disbenefits on different species, and those effects are highly geographically variable. Reductions in NH₃ emissions are effective at decreasing NH₃ concentrations and deposition but much less so for NH₄⁺. A 40 % NH₃ emissions reduction decreases regional average NH₃ concentrations by 47&ndash;49 %, while sensitivities of NH₄⁺ concentrations decrease in the order Euro_Medi (Europe and Mediterranean, 18 %), East Asia (15 %), North America (12 %), and South Asia (4 %), reflecting the increasing regional ammonia-richness. A disbenefit is the increased SO₂ concentrations in these regions (10&ndash;16 % for 40 % NH₃ emissions reductions) because reduced NH₃ levels decrease SO₂ deposition by altering atmospheric acidity. The 40 % NO_x emissions reductions decrease NO_x concentrations in East Asia by 45 %, Euro_Medi and North America by ~38 %, and South Asia by 22 %, whilst decreases in fine NO₃^- are regionally reversed, which is related to enhanced O₃ levels in East Asia (and also, but by less, in Euro_Medi), and decreased O₃ levels in South Asia (and also, but by less, in North America). Consequently, the oxidation of NO_x to NO₃^- and of SO₂ to SO₄^2- is enhanced in East Asia but decreased in South Asia, which in East Asia causes a more effective decrease in NO_x and SO₂ but a less effective decrease in NO₃^- and even an increase in SO₄^2-; in South Asia it causes a less effective decrease in NO_x and an increase in SO₂ but a more effective decrease in NO₃^- and SO₄^2-. For regional policy making, it is thus important to reduce NH₃, NO_x and SO_x emissions together and/or go for stronger reductions to minimise such adverse effects in East Asia and Euro_Medi. Reductions in SO_x emissions are slightly more effective for SO₂ than SO₄^2-. A disbenefit is that SO_x emissions reductions increase NH₃ total deposition and ecosystem eutrophication (~12 % increase for 40 % emissions reduction). PM_2.5 mitigation in South Asia is most sensitive to 40 % SO_x reduction (3.10 &mu;g m^-3, 10 %) and least sensitive to NH₃ reduction (0.29 &mu;g m^-3, 1 %), which is because South Asia is so ammonia-rich that reducing NH₃ has little impact. The most effective measure for North America is reducing NO_x emissions with an 8 % (0.63 &mu;g m^-3) decrease in PM_2.5 in response to a 40 % reduction. In Euro_Medi, the sensitivities of PM_2.5 to 40 % individual emissions reductions range 5&ndash;8 % (0.55&ndash;0.82 &mu;g m^-3). In the UK and Scandinavia PM_2.5 is more sensitive to NH₃, in central Europe it is more sensitive to NO_x, while in the Mediterranean it is more sensitive to SO_x. In East Asia, reductions in SO_x, NO_x and NH₃ emissions are almost equally effective with PM_2.5 sensitivities to 40 % reductions of 7&ndash;8 % (1.89&ndash;2.33 &mu;g m^-3). Due to the varying contributions of SIA, PM_2.5 sensitivities to 40 % collective reductions in all 3 precursors decrease in the order East Asia (20 %), Euro_Medi and North America (17 %), South Asia (13 %). The geographically-varying non-linear chemical responses of N_r, S_r, and PM_2.5 to emissions reductions revealed by this work show the importance of both prioritising emissions strategies in different regions and combining several precursor reductions together to maximise the policy effectiveness.

Meteorological variations impeded the benefits of recent NOx mitigation in reducing atmospheric nitrate deposition in the Pearl River Delta region, Southeast China

Impact of H2 addition on flame stability and pollutant emissions for an atmospheric kerosene/air swirled flame of laboratory scaled gas turbine

Hydrogen serves as an optimal fuel for engines. Pure hydrogen engines do not generate carbon monoxide and hydrocarbon emissions; instead, they encounter significant nitrogen oxide emissions. Inner-engine control and outer-engine control are two methods to reduce NOx emissions. Outer-engine control primarily mitigates NOx emissions by selective catalytic reduction (SCR), a process that has been extensively researched. Nevertheless, there is a paucity of research about NOx emission regulation in pure hydrogen engines via internal engine management. This work utilised the closed homogeneous reactor (CHR) in Chemkin Pro to model the primary NOx emission control within pure hydrogen engines. The findings indicate that single exhaust gas recirculation (EGR) reduces NOx emissions by 45.3% at an EGR ratio of 20%, suggesting that the reduction in NOx emissions is not substantial. Nonetheless, EGR combined with lean burn reduces NOx emissions by 96.31% at a λ of 1.4 and an EGR ratio of 20%, resulting in ultra-low NOx emissions from pure hydrogen engines. In comparison to single EGR and EGR combined with lean-burn, SNCR is more effective for NOx emission control. An NH3 ratio of merely 10% can reduce NOx emissions by 96.32% in pure hydrogen engines, whilst a 15% NH3 ratio can attain zero NOx emissions in pure hydrogen engines without necessitating a high λ value or EGR ratio. It is essential to precisely regulate the NH3 ratio in the cylinder; otherwise, residual NH3 may be generated, leading to environmental pollution.

&amp;lt;p&amp;gt;Satellite observations provide unique information on the amount and spatial distribution of tropospheric NO2. Several studies use such datasets for deriving NOx emissions. However, due to nonlinearities in the NOx chemistry (i.e., the dependency of the OH concentration and thus the NO2 lifetime on the NO2 concentration), the observed column densities of NO2 are not directly proportional to the underlying NOx emissions. Consequently, a certain reduction in NOx emissions could result in disproportionate reduction of the corresponding NO2 columns, which could be stronger or weaker depending on the chemical state (O3, NOx and VOC levels) and conditions like temperature, humidity and acitinic flux. This effect complicates the quantification of NOx emissions from satellite measurements of NO2, and e.g. biases the emission reduction as derived from the reduction of NO2 column densities observed during recent lockdowns. &amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Here we quantify the nonlinearity of the NOx system for different cities as well as power plants by investigating the effect of reduced NOx emissions on days of rest, i.e. Fridays/Sundays in Muslim/Christian culture, respectively. The reduction of NOx emissions is thereby quantified based on the continuity equation by calculating the divergence of the mean NO2 flux. This method has been proven to be sensitive for localized sources, where the uncertainties due to NO2 lifetime are small (Beirle et al., Sci. Adv., 2019). This reduction in emissions is then set in relation to the corresponding reduction of NO2 columns integrated around the source, which strongly depend on the NO2 lifetime.&amp;lt;/p&amp;gt;

Assessing the performance of the transport sector within the global supply chain context: Decomposition of energy and environmental productivity

Alcohol-based biofuels, including butanol and ethanol, have garnered heightened attention due to an impending global demand for sustainable transportation fuels. Nevertheless, the potential of propanol, an additional alcohol-based fuel, has not been completely evaluated, particularly in comparison to its counterparts. In this investigation, the environmental and performance characteristics of propanol, ethanol, and butanol are compared when blended with gasohol. This study conducts a comprehensive comparison of the environmental and performance characteristics of propanol, ethanol, and butanol blends when combined with gasohol. Key areas of focus include engine performance, fuel stability, and emissions profiles (CO, NOx, HC, and CO2). Experimental analyses, encompassing varying blend ratios (BR), engine speeds, and compression ratios, reveal that optimized propanol-gasohol blends significantly reduce greenhouse gas and pollutant emissions while enhancing engine efficiency compared to ethanol and butanol blends. Optimized blend ratios exhibit the potential to reduce emissions while additionally enhancing engine efficiency, thereby facilitating the development of further sustainable and environmentally friendly fuel alternatives. These findings reveal potential biofuel strategies for the transportation sector that are designed to mitigate its environmental implications. The optimized propanol-gasohol blends achieved a 15 % reduction in CO2 emissions, 10 % reduction in NOx emissions, and 12 % reduction in HC emissions, while improving engine performance metrics such as combustion efficiency. This study’s originality lies in its comprehensive evaluation of propanol as a fuel additive, addressing gaps in the literature related to its emissions, engine performance, and optimization. Unlike ethanol and butanol, propanol’s unique properties, including improved emission reductions and compatibility, were systematically investigated under varied operating conditions. These findings provide new perspectives on sustainable fuel development.

Experimental and numerical studies were performed to investigate the simultaneous reduction of NOx and CO for stoichiometric diesel combustion with a 3-way catalyst. A single-cylinder engine was used for the experiments and KIVA simulations were used in order to characterize the combustion efficiency and emissions of throttled stoichiometric diesel combustion at 0.7 bar boost pressure and 90MPa injection pressure. In addition, the efficiency of emission conversion with the 3-way catalysts in stoichiometric diesel combustion was investigated experimentally. The results showed CO and NOx emissions can be controlled with the 3-way catalyst in spite of the fact that CO increases more at high equivalence ratios compared to conventional diesel combustion (i.e., lean combustion). At stoichiometric operation, the 3-way catalyst reduced CO and NOx emissions by up to 95%, which achieves lower emissions compared to conventional diesel combustion or low temperature diesel combustion, while keeping better fuel consumption than a comparable gasoline engine.