Combustion Emissions Research Articles

Quantifying the Diversity of an Atmospheric Aerosol Population in an Arctic Oil Field on a Single‐Particle Level

AbstractAs the Arctic rapidly warms, sea ice extent is decreasing and oil and gas extraction activities are expanding. Local combustion emissions affect the Arctic atmospheric aerosol chemical mixing state (the distribution of chemical species across the aerosol population), which impacts climate‐relevant properties. Bulk and single‐particle measurements of submicron aerosols were conducted at Oliktok Point, Alaska within the North Slope of Alaska oil fields. In this work, we quantify aerosol diversity using online single‐particle mass spectrometry data (32,880 individual particles), offline single‐particle microscopy data (20,912 individual particles), and online bulk aerosol mass spectrometry and aethalometer data. This method was used to derive individual particle mass fractions for both refractory and non‐refractory material within distinct particle types. Single‐particle, average single‐particle, and bulk population diversities (Di, Dα, Dγ, respectively) and mixing state indices (χ) were calculated for the data set. Calculated Di values were generally low (2.2 ± 0.6), as individual particle masses were dominated by a few chemical species of interest. Aged aerosol particles (those internally mixed with nitrate and/or sulfate) exhibited higher Di values (>3) compared to recently emitted (fresh) aerosol particles. During oil field plume periods, Dα values approached three due to the abundance of diesel combustion particles, which were rich in sulfate, black carbon, and organic aerosol. Overall, the submicron aerosol population within the Arctic oil fields was found to be relatively externally mixed (χ < 50%), due to the constant local emissions within oil fields combining with background aerosol and locally emitted sea spray aerosol at the coastal site.

NUMERICAL INVESTIGATION OF WATER ADDITION INTO INTAKE AIR IN MODERN AUTOMOBILES DIESEL ENGINES

In the present study, the effects of water addition into intake air (WAIA) on combustion, engine performance, and NO emission in diesel engines were investigated numerically. Here, Ferguson's thermodynamic-based zero-dimensional single-zone cycle model was used and improved with some new approaches for neat diesel fuel (NDF) and WAIA. After controlling the model's accuracy for NDF and WAIA, the effects of WAIA were first investigated in the Renault K9K diesel engine. For (5 and 7.5)% water ratios (WRs), effective power decreased by 4.26% and 7.37%, brake specific fuel consumption (BSFC) increased by 6.95% and 10.56%, and NO emission reduced by 12.43% and 16.39%, respectively. In the second application, the effects of (3, 6, and 9)% WRs on combustion, engine performance, and NO emission in the Renault M9R type diesel engine were investigated at 4000 rpm by using this developed model. For (3, 6, and 9)% WRs, BSFC increased by 0.97%, 3.39%, and 8.25%, and NO emission decreased by 10.31%, 17.66%, and 34.20%, respectively. For (3 and 6)% WRs effective power increased, and NO emission decreased significantly without considerable deterioration in the BSFC at 4000 rpm. Cylinder pressure values and heat release rate increased for (3 and 6)% WRs and decreased for 9% WR.

Numerical simulation of VAM assisted combustion gas turbine

In order to save energy and protect environment, how to utilize ventilation air methane (VAM) is a subject that needed urgently to be studied. The methane concentration in VAM varies greatly, making it difficult for traditional burners to burn directly. Therefore, the feasibility of using VAM as a combustion gas for gas turbines is considered. When natural gas is used as the fuel for a micro gas turbine, the changes in air inlet parameters will directly affect its performance. This article uses experimental and numerical simulation methods to analyze the feasibility of using VAM as combustion air for micro gas turbines. The results show that factors such as intake pressure, temperature, and composition of gas turbines have an impact on combustion and pollutant emissions; the comparison between VAM and air as combustion gases shows that the rate of temperature increase in the combustion chamber increases, and the concentration of NO at the outlet of the combustion chamber increases by 0.97 % and the concentration of CO increases by 3.76 %. Based on the comprehensive analysis of gas turbine performance, it is concluded that the application of mine exhaust air to micro gas turbines has certain feasibility.

A pathway for implementing ammonia solutions as fuel blends for achieving low-emission combustion in diesel engines

The intriguing exploration of ammonia fuel has captured the spotlight of researchers, heralded for its status as a zero-carbon fuel and acclaimed as a potent inhibitor of NOx emissions in internal combustion engines. Ammonia solution, one of the forms of ammonia fuel, demonstrates its ability to blend seamlessly with conventional fuel. However, the slower combustion reaction of ammonia is a significant challenge to overcome. One of the effective approaches to improve the combustibility of ammonia fuel in diesel engines is to blend ammonia solution with diesel emulsion fuel. So, the focus of this study was to comprehensively analyze the effects of blending ammonia solution at various concentrations with diesel emulsion fuel and to closely examine their effects on combustion sustainability and emission profiles in diesel engines. The ammonia solution used is an aqueous solution containing 28 wt% of ammonia. Herein, five different fuel samples were examined: diesel, water/diesel (W/D), and W/D containing 1, 3, and 5 wt% ammonia solution (A1%-W/D, A3%-W/D, and A5%-W/D, respectively). The tests were carried out with a conventional diesel engine running at a fixed engine speed of 2400 rpm, while the loads were adjusted to a variety of levels. Interestingly, we found that the diesel emulsion containing a 5 wt% ammonia solution is ineffective in diesel engines, leading to performance degradation and unstable combustion. Compared with diesel, the rate of heat release was increased by 17.6 %, 15.3 %, 10.9 % for W/D, A1%-W/D, and A3%-W/D, respectively. Furthermore, the presence of ammonia solution prolonged the ignition delay period and facilitated the reduction of NO emissions. Compared with diesel fuel, the W/D, A1%-W/D, and A3%-W/D fuels reduced NO emissions by 39.3 %, 29.5 %, and 25 %, respectively. The results of this study demonstrated that the introduction of ammonia solution at concentrations up to 3 % by weight blended with diesel emulsion fuel can be effectively combusted in a diesel engine, promoting sustained combustion stability while contributing to a significant reduction in exhaust emissions.

An Experimental Study using Diesel Additives to Examine the Combustion and Exhaust Emissions of CI Engines

An Experimental Study using Diesel Additives to Examine the Combustion and Exhaust Emissions of CI Engines

Ammonia energy fraction effect on the combustion and reduced NOX emission of ammonia/diesel dual fuel

With stringent regulations of internal combustion engine on reducing CO2 emission, ammonia has been used as an alternative fuel. Investigating how engine-related performance is affected by partial ammonia replacement of diesel fuel is essential for understanding the combustion. Therefore, in this study, a three-dimensional numerical simulation model is developed for the burning of two fuels of diesel and ammonia based on relevant parameters (i.e., compression ratio, load, ammonia energy fraction, etc.) in a lab-made diesel engine. The consequences of load and compression proportion on combustion and pollutant emissions are investigated for ammonia energy fractions between 50% and 90%. When the ammonia portion rises, the increased ammonia equivalent ratio causes ammonia to move away from the dilute combustion boundary and accelerates the combustion rate of ammonia. An increase in compression ratio significantly increases the specified thermal performance and combustion efficacy. When the compression ratio is 16, as the ammonia energy fractions increases, due to the increase in the proportion of ammonia, that is, the proportion of nitrogen atoms increases, more NOx is generated during the combustion process. When the ammonia substitution rate is 90%, as the compression ratio increases, the cylinder pressure and temperature increase. The combustion efficiency of ammonia increases, generating more NOx and NOx emissions can reach 0.66 mg/m3. At a compression ratio of 18, the NOx emissions can reach 1.59 mg/m3. However, under medium and low load conditions, as the ammonia fraction increases, the total energy of fuel decreases, and the combustion efficiency of ammonia decreases, resulting in a decrease in the heat released during combustion and a decrease in NOx emissions. When the ammonia substitution rate is 90% and the load is 25%, NOx emissions reach 0.1 mg/m3. This research provides theoretical suggestions for the profitable and use ammonia fuel in internal combustion engines in a clean manner.

Study on the integration of hydrogen in a multi-cylinder low heat rejection diesel engine using a ternary blend

Among alternative fuels, hydrogen (H2) holds significant promise as both a fuel and an energy carrier. It is expected to become a key alternative fuel in the near future to meet stringent pollution standards. H2 is used in internal combustion (IC) engines, gas turbines, and the aerospace industry due to its non-toxic and odorless nature, high calorific value (CV), and wide temperature range of combustibility. Additionally, it is a long-term renewable energy source that produces fewer pollutants. This study explores the impact of different H2 ratios on combustion behavior, engine performance, and emission characteristics in a dual-fuel compression ignition (CI) diesel engine. The current research focuses on the effect of TB of ethanol, Jatropha methyl ester, and diesel with the induction of H2 with different flow rates in diesel engine in dual fuel mode (DFM). The tests were performed at different engine loads, 25%, 50%, 75%, and 100% at a constant engine speed of 2500 rpm. H2 is inducted at different flow rates like 2, 4, and 6 Litres per minute (lpm). Partially stabilized zirconia (PSZ) is used to coat the cylinder head, piston crown, and valves with a thickness of 0.5 mm. The combined effect of TB fuel and H2 in a CI engine improves combustion and engine performance. At full load condition, brake thermal efficiency (BTE) is improved by 11.5% for TB fuel with H2 at 6 lpm, and exhaust gas temperature (EGT) increased by 12.7%. The cylinder pressure (CP) and heat release rate (HRR) are increased by 7.5% and 10.6% at TB fuel with 6 lpm of H2 induction. The utilization of H2 as an alternative energy source has significant consequences for the future of green energy production.

Projection of the Airborne CO2 Concentration by Land/Ocean Absorption Dynamics and Fossil-Fuel Reserve Depletion

The paper has been suggested by the following observations: (1) the atmospheric growth rate of carbon dioxide concentration is smaller than that ascribed to the emission of fossil-fuel combustion and (2) the fossil-fuel reserves are finite. The first observation leads to a simple dynamic model, based on the balance of CO2 land/ocean absorption and anthropogenic emissions, only limited by the depletion of fossil-fuel reserves, in a business-as-usual scenario. The second observation suggests of projecting the past CO2 emissions to the future, by constraining emissions to the limit of reserve availability. Similar projections are available in the literature, but either driven by heuristics or by complex simulation packages. The paper provides a simple and formal method only driven by historical data, their uncertainty and simple models. The method aims to provide CO2 concentration projections, which being constrained by fossil-fuel finite reserve may be in principle employed as bounds to forecasting exercises. The time–invariant dynamics of the land/ocean absorption is the simplification of a more complex set of equations describing carbon dioxide exchange between different reservoirs. Contribution of other greenhouse gases like methane and nitrous oxide has been neglected, since their emissions cannot be projected with the paper methodology. Comparison with recent profiles of the Intergovernmental Panel on Climate Change (IPCC) confirms that the finite-reserve projections of the fossil fuel emissions is close to those of a moderate Shared Socioeconomic Scenario (SSP) like SSP2-4.5—a result in agreement with other authors—but also reveals the limits of the simplified model, when extending the tuned dynamics of the recent mean CO2 exchanges to long-term future. The limits derive from linearity, time invariance, and aggregation assumptions, which allow a more complex model of CO2 exchanges to be simplified and tuned on experimental data.

Jet ignition characteristics of ammonia-hydrogen passive pre-chamber: Emphasis on equivalence ratio and hydrogen/ammonia ratio

Ammonia-hydrogen blend fuels offer the potential for zero-carbon emissions in internal combustion (IC) engines. To improve combustion performance, considerable attention has been focused on pre-chamber jet ignition technologies. Passive pre-chamber featuring a simple structure can be installed in the spark plug hole without modifying the cylinder head. However, the jet ignition characteristics of ammonia-hydrogen passive pre-chambers are not fully understood, and there is a lack of visualized evidence on how critical parameters (e.g., equivalence ratio and hydrogen/ammonia ratio) impact ignition processes. This work investigated the effects of equivalence ratio and hydrogen/ammonia ratio on ammonia-hydrogen jet ignition characteristics in a rapid compression machine with passive pre-chamber. High-speed photography and instantaneous pressure acquisition were employed to capture detailed ignition and combustion evolutions. Results show that under low hydrogen/ammonia ratio conditions, there exists a combustion regime with noticeable fluctuations in jet penetration, indicating degenerate ignition performance. As the hydrogen/ammonia ratio increases from 0 % to 20 %, the ignition delay time of mixtures in the main chamber is reduced by 70 %, suggesting an improved overall ignition performance. Regarding the equivalence ratio, more pronounced effects on jet ignition and flame propagation are identified under lean-burning conditions. For mixtures at the hydrogen/ammonia ratio of 20 %, as the equivalence ratio increases from 0.6 to 0.8 and from 0.8 to 1.0, the decay rates for 10 %–90 % combustion duration are 82.5 % and 20.6 %, respectively. Besides, with the increase of equivalence ratio, flame initiation is shifted from the jet head to the side surface. The role of hydrogen/ammonia ratio and equivalence ratio is different, with the former modifying mixture reactivity while the latter affecting ignition energy.

Characterizing multi-pollutant emission impacts of sulfur reduction strategies from coal power plants

Fuel combustion for electricity generation emits a mix of health- and climate-relevant air emissions, with the potential for technology or fuel switching to impact multiple emissions together. While there has been extensive research on the co-benefits of climate policies on air quality improvements, few studies have quantified the effect of air pollution controls on carbon emissions. Here we evaluate three multi-pollutant emission reduction strategies, focused on sulfur dioxide (SO2) controls in the electricity sector. Traditional ‘add-on’ pollution controls like flue gas desulfurization (FGD) reduce SO2 emissions from coal combustion but increase emissions of nitrogen oxides (NO X ), volatile organic compounds (VOCs), fine particulate matter (PM2.5), and carbon dioxide (CO2) due to heat efficiency loss. Fuel switching from coal to natural gas and renewables potentially reduces all pollutants. We identified 135 electricity generation units (EGUs) without SO2 controls in the contiguous US in 2017 and quantified the unit-level emission changes using pollution control efficiencies, emission rates, fuel heat input, and electricity load. A cost-benefit analysis is conducted, considering pollution control costs, fuel costs, capital and operation and maintenance (O&M) costs, the monetized health benefits from avoided multi-pollutant, and the social cost of carbon as the benefit for carbon reduction. We find that add-on SO2 controls result in an average annual net benefit of $179.3 million (95% CI: $137.5-$221.0 million) per EGU, fuel switching from coal to natural gas, $432.7 million (95% CI: $366.4-$498.9 million) per EGU; and fuel switching from coal to renewable energy sources, $537.9 million (95% CI: $457.1-$618.9 million) per EGU. Our results highlight multi-pollutant emission reduction strategy as a cost-effective way to synergistically control air pollution and mitigate climate change.

Comprehensive pollutant emission prediction models from hydrogen-enriched methane combustion in a gas-fired boiler based on box-behnken design method

Hydrogen-enriched methane (HEM) combustion is an effective method for reducing the consumption of carbonaceous fuels. However, high adiabatic flame temperature of H2 can cause large NO emissions. To reduce the NO and CO2 emissions from HEM combustion, the Box-Behnken design (BBD) method combining response surface experimental design, analysis of variance, and multi-nonlinear regression models was adopted. The effects of the H2 doping ratio (XH2), preheated air temperature (Tair), excess air coefficient of burners arranged at the bottom (Ex,b), and their interactions on the NO, N2O, and CO2 emissions of a gas-fired boiler were investigated. According to the BBD method, the NO, N2O, and CO2 emissions prediction models with R2 exceeding 0.98 were proposed, respectively. The results showed that the increase of Tair had a positive effect on reducing NO emissions, as the NO exhausted from HEM combustion is mainly thermal NO. Compared with Tair and Ex,b, XH2 was the most significant factor affecting N2O and CO2 emissions, indicating that an increase in XH2 can significantly reduce greenhouse gas emissions. Additionally, the formation and consumption of N2O emissions presented a competitive mechanism at XH2 increased from 0 to 0.8, and CO2 emissions reduced with the increase of XH2, Tair, and Ex,b. Furthermore, a comprehensive emission prediction model with NO, N2O, and CO2 emissions was proposed. With the target of minimizing total NO, N2O and CO2 emissions, three groups of combinations for XH2, Tair, and Ex,b were obtained from the equal weight, entropy weight method, and criteria importance through the inter-criteria correlation method as 1:1:1, 24:9:17, and 21:11:18. The results showed that for minimize emissions, there is not much difference in the results calculated based on the optimal boundary conditions under different weights. For various reduction targets for nitrogen, carbon, and greenhouse gases, three groups of optimal combinations of XH2, Tair, and Ex,b were obtained and their accuracies were verified based on numerical calculations with relative errors below 6%. The proposed comprehensive pollutant emission prediction models are conducive to calculating the pollutant emissions of HEM combustion and guiding the investigation of prediction models considering other operating conditions.

The impact of scavenging air state on the combustion and emission performance of marine two-stroke dual-fuel engine

The scavenging process significantly affects the combustion and emission performance of marine low-speed two-stroke dual-fuel engines. Optimizing scavenging air pressure and temperature can enhance the engine's combustion efficiency and emission control performance, thereby achieving more environmentally friendly and efficient operation of dual-fuel engines. This study focuses on marine low-speed two-stroke dual-fuel engines, analyzing the effects of scavenging air pressure (3.0 bar, 3.25 bar, 3.5 bar, and 3.75 bar) and scavenging air temperature (293 K, 303 K, and 313 K) on engine performance and emission products. The results indicate that scavenging air pressure has a greater impact on engine performance than scavenging air temperature. An increase in scavenging air pressure leads to higher thermal efficiency and power. As the scavenging air pressure increases from 3 to 3.75 bar, the indicated thermal efficiency (ITE) increases from 44.02 to 53.26%, and indicated mean effective pressure (IMEP) increases by approximately 0.35 MPa. Increased scavenging air pressure improves nitrogen oxide (NOx) and hydrocarbons (HC) emissions. For every 0.25 bar increase in scavenging air pressure, NOx emissions decrease by 3.53%, HC emissions decrease by 33.35%, while carbon dioxide (CO2) emissions increase by 0.71%. An increase in scavenging air temperature leads to lower ITE and IMEP. As the air temperature changes from 293 to 313 K, the ITE decreases by approximately 1%, and IMEP decreases by about 0.04 MPa. Increased scavenging air temperature improves CO2 emissions. For every 10 K increase in the air temperature, the CO2 emissions decrease by 0.02%, while NOx emissions increase by 4.84%, HC emissions increase by 34.39%. Therefore, controlling scavenging air pressure is more important than scavenging air temperature in the operational management of marine two-stroke engines. Higher power and lower NOx and HC emissions can be achieved by increasing the scavenging air pressure.

Analysis of Ozone and VOCs Pollution Characteristics, Sources, and Abatement Control Strategies in Hebi

In order to control the increasing ozone （O3） pollution in Hebi, Henan Province, clarifying the pollution characteristics of ozone and its precursors is vital. Therefore, we conducted a comprehensive analysis of O3 pollution utilizing the OFP-PMF-EKMA method combined with online hourly resolution monitoring data of conventional pollutants and volatile organic compounds （VOCs） in the summer of 2022 （June-September）. Ozone formation potential （OFP） was used to identify the key VOCs species, and the PMF model was used to identify the VOCs emission sources, whereas EKMA curves and scenario analysis were used to identify the main ozone control area in Hebi and to determine the reduction ratio of VOCs and NOx in a scientifically refined way. In 2022, Hebi had persistent O3 pollution, with the highest concentration in June. Conditions of high temperature, low humidity, and low atmospheric pressure contributed to the O3 accumulation. Aromatic and oxygenated volatile organic compounds （OVOCs） contributed significantly to the OFP and VOCs fraction, which were the dominant active substance and concentration dominant species. The results of the VOCs source analysis indicated that vehicle exhaust sources （25.3%） were the main source of atmospheric VOCs, followed by process sources （17.7%） and biomass combustion sources （17.6%）. Thus, emission sources associated with the combustion of fossil fuels and industrial production emissions were the most urgent sources of atmospheric VOCs to be controlled in Hebi. The O3 generation in Hebi occurred in the VOCs-sensitive zones, and the emission reduction results showed that a synergistic emission reduction of VOCs and nitrogen oxide （NOx） could effectively control O3 pollution with a 75% reduction in VOCs and a 10% reduction in NOx.

Distribution and bioaccumulation status of polycyclic aromatic hydrocarbons (PAHs) in Veraval coastal waters using copepods as bio-indicators.

The study investigates the pollution characteristics of 16 priority PAHs, accumulated in copepods from a major fishing harbour and its adjacent coastal waters of Veraval, west coast of India. The total PAH accumulation is in the range of 922.16-27,807.49ngg-1 dw, with the mean concentration of 5776.59ngg-1 dw. High concentrations of PAHs were present in the copepod samples from inside the harbour. Notably, there was no significant correlation between the lipid content of copepods and the accumulation of PAHs. The molecular diagnostic ratio method (MDR) indicates that the PAH sources are petrogenic in origin, while principal component analysis (PCA) points to petroleum, coal combustion and vehicular emission sources. Total cancerous PAHs (C-PAHs) in the study area dominate by 40% of the total PAHs identified; moreover, the bioaccumulation factor (BAF) is very high in the offshore area, which is also a fishing ground. The global relevance and magnitude of the present study in the Veraval, one of the prime seafood exporting hubs in India, should be dealt with utmost avidity as the accumulation status of PAHs in the zooplankton has never been explored in the Indian coastal waters. Moreover, the current study gives the foremost data on the bioaccumulation status of PAHs in copepods from the tropical waters of India.

Flame stabilization and pollutant emissions of turbulent ammonia and blended ammonia flames: A review of the recent experimental and numerical advances

Compared to traditional hydrocarbon fuels, ammonia presents significant challenges as a fuel, including high ignition energy, low reactivity, slow flame propagation, and high NOx emissions, which hinder its use as a renewable fuel. Blending ammonia with fossil fuels like natural gas improves its combustion reactivity and helps mitigate CO2 emissions. However, there is still much to understand about the complex dynamics of ammonia and its blends with hydrocarbons. Key areas such as reaction kinetics mechanisms, ignition properties, flame propagation behaviors, and methods for controlling combustion performance under various conditions require further elucidation. This paper reviews recent advancements in experiments and numerical simulations aimed at developing stable, and low-emission combustors for ammonia-fired power generation. Recent burner and flame configurations, including non-swirling jets, single-stage swirl burners, two-stage burners, and newly developed double-swirl burners are analyzed for their flame stability and pollutant emission potential when firing ammonia and ammonia blends. Chemical kinetic modeling of ammonia and its blends plays a crucial role in understanding combustion behavior and pollutant emissions, particularly for NOx. However, there are challenges in predicting NOx emissions accurately, with significant disparities among different models. High-fidelity numerical simulations using detailed and skeletal mechanisms, direct numerical simulation, and large eddy simulation, have helped uncover crucial operational conditions affecting combustion and pollutant emissions, such as combustor pressure, air dilution, wall cooling, fuel/air mixing, and fuel blending. Nonetheless, the accuracy of chemical kinetic models and their integration into turbulent flow simulations remain critical limitations for numerical simulations of ammonia combustion.

Impacts of fuelling methods on knock-limited combustion and emissions of a dedicated hybrid spark-ignition engine

This study investigates the impact of various fuelling methods on knock-limited combustion efficiency and emissions in a high compression ratio, turbocharged spark-ignition gasoline engine designed for hybrid applications. Different injection strategies, including port fuel injection (PFI), direct injection (DI), two-stage DI, PFI with late DI, and PFI with in-cylinder targeted fuel injection (TFI), were evaluated. TFI, a novel method where fuel is injected towards knock-prone regions based on knock spatial distribution, was seen capable of advancing the knock-limited spark advance (KLSA) by up to 3.75°, and hence reducing fuel consumption by 18.78 g/kWh, demonstrating significant knock suppression. Furthermore, trade-off characteristics between fuel consumption and particulate emissions resulting from injection strategies were exhibited from the measured data. DI produces the optimal fuel consumption and the worst particulate emissions, while PFI shows the opposite. Importantly, TFI improves the trade-off, reducing fuel consumption and emissions simultaneously. The refined TFI achieved a 96.6 % reduction in particulate emissions compared to DI, matching PFI levels while improving engine thermal efficiency. These different combustion characteristics are attributed to the localized fuel–air mixing and charge cooling affected by injection strategies.

Measurements of ignition delay time of gas-to-liquid (GTL) fuel blends

The ignition delay time (IDT) is a fundamental combustion parameter of any fuel, which has a direct impact on its combustion and exhaust emissions in diesel engines. In this research, a thorough experimental study was conducted to investigate the ignition delay of Gas-to-Liquid (GTL) fuel and its 50%–50 % blends with diesel under a wide range of operating conditions using a conventional shock tube apparatus. Simultaneously, a comprehensive chemical kinetic model, based on the well-established POLIMI mechanism, was developed to simulate the complex combustion chemistry of diesel, GTL, and their blends. Several loading pressures in the driver section ranging from 6 to 14 bar that results in reflected pressure of 8–16 bar, and equivalence ratios ranging from 0.5 to 1.3 as well as different initial temperatures have been examined. Calibration of the shock tube indicated that a driver gas tailoring technique was necessary to be used, which was conducted by adding a small ratio of either argon or nitrogen to helium to get an extended test time by 32 % with a good rapture pressure. IDT measurements showed that GTL has the shorter ignition delay time than that of diesel fuel for all conditions. The findings show that IDT measurements for GTL fuel has a shorter ignition delay time than that of diesel fuel for all conditions. Under stoichiometric conditions (ɸ = 1.0), IDT of the blended fuel was about 3 ms, very close to that of GTL at 975 K. However, at a temperature above 1000 K, the IDT of the three fuels were almost identical and ranging between 1 and 2 ms. At a temperature of 1100 K, the IDT of the blended fuel was 5.5 ms, almost a middle value between those of the pure diesel, 0.522 ms, and GTL fuel, 0.495 ms. The shortest IDT of the blended fuel was about 0.4 ms with the highest value of the reflected pressure of 14 bar, while the longest IDT was around 10 ms with the rich mixture at ɸ = 1.3. The study can add to the existing literature illustrating the behavior of GTL-diesel blend can affect IDT.

Characteristics, sources, and health risks of PAHs and their derivatives in indoor dust in Zhengzhou

The occurrence, source, and health risk of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) in indoor dust collected from three types of microenvironments (offices, classrooms, and dormitories) at a university campus in Zhengzhou were analysed. The results showed that the average concentration of the total PAHs was 2403.21 ± 981.99 ng g−1, with PHE (20.06% of Σ18PAHs) and BkF (15.46%) being the dominant species. The average concentrations of total NPAHs and OPAHs were 11.09 ± 5.12 and 385.80 ± 255.27 ng g−1, with 2+3N-FLT (39.15%) and 9-FLO (39.76%) as the most abundant species of NPAHs and OPAHs, respectively. The average concentrations of total PAHs, NPAHs, and OPAHs in different microenvironments displayed obvious spatial specificity with the highest values in dormitories. The main source of PAHs, as identified by diagnostic ratios, was petroleum combustion, coal/biomass combustion and vehicle exhaust emissions. The average incremental lifetime cancer risk (ILCR) for undergraduates exposed to dust in classrooms and dormitories exceeded 10−6, indicating a potential cancer risk. The most important exposure pathway was dermal contact, while the inhalation route was negligible.

The Impact of Incorporating Varying Proportions of Sugar Beet Waste on the Combustion Process and Emissions in Industrial Burner Fuelled with Conventional Diesel Fuel

Abstract The main objective of the case study is to investigate the effectiveness of using solid fuel additives in conventional diesel fuel for industrial furnaces. The study focuses on utilizing agricultural waste derived from sugar beet plant waste as additives to enhance the combustion process and reduce emissions from industrial burners. In this study, experimental measurent for the flame temperatures inside the furnace while altering the proportions of the solid materials have ben achived. The goal was to assess the impact of different loading from these additives on the combustionprocess. Furthermore, the study involved measuring exhaust gases such as carbon monoxide (CO), carbon dioxide (CO2), unburned hydrocarbon (UH), and nitrogen oxides (NOx). The experimental facility arranment allowed the researchers to evaluate the emissions resulting from the combustion process with the addition of solid fuel additives. By measuring these parameters, the study aimed to understand the effect of utilizing agricultural waste as additives on the burning processes and emission formation in industrial furnaces. These findings can contribute to improving the efficiency of combustion processes, reducing emissions, and promoting the utilization of renewable and sustainable fuel sources in industrial settings. In this study, varying the proportions of solid materials used as additives had an impact on the levels of carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxides (NOx) in the exhaust gases. By increasing the proportion of solid materials in the fuel mixture resulted in changes in the emission levels. The levels of carbon monoxide in the exhaust gases decreased as the proportion of solid materials increased. While the addition of solid fuel additives did contribute to the production of CO2 due to the combustion of the additives, the overall effect on its levels varied depending on the specific proportions used. Also, the levels of nitrogen oxides in the exhaust gases showed different trends depending on the proportions of solid materials used. Typically, increasing the proportion of solid fuel additives led to reduce NOx emissions. However, this may also depend on other factors such as combustion temperature and the composition of the solid materials.

Effect of swirl number on structural and emission characteristics of moderate size burner flames

An experimental investigation was conducted on the flame characteristics, thermal properties, and emissions of industrial-scale (40 kW) diesel flames. This study uniquely measured structural (flame length, diameter, volume), thermal (temperature, heat flux), and emission characteristics (COX, NOX, Unburnt HC) across various equivalence ratios (0.2–0.6) and swirling conditions (Swirl number varying from 0.73 to 1.04). Results indicated that higher swirl numbers generally led to more stable and compact flames, though structural properties were less affected during lean combustion. Notably, flame temperature varied significantly, up to 350 K, resulting in substantial difference in specified emission products. The emission reductions were achieved, particularly with a geometric swirl number of 1.04, which balanced flame performance and emission both, achieving reductions in CO (9–97 %), HC (18–96 %), NO (8–16 %), and Smoke (0.3–82 %). These findings underscore the critical impact of swirl angle on combustion efficiency and emissions, highlighting the need for meticulous optimization to mitigate harmful emissions effectively. This study provides new insights into optimizing combustion parameters for enhanced environmental sustainability in industrial processes.