Carbon Monoxide Emissions Research Articles

Performance and Exhaust Emissions from Diesel Engines with Different Blending Ratios of Biofuels

Fossil fuel extraction and utilization are associated with several environmental issues. This study examined how altering the blending proportions of mixed diesel/biodiesel/n-butanol fuels impacts combustion. Additionally, it delved into the functioning of diesel engines when utilizing these blended fuels as well as conventional diesel. A three-dimensional fluid dynamics simulation was constructed and corroborated against test outcomes obtained at 25%, 50%, 75%, and 100% loads. The findings indicated that the n-butanol addition enhanced the indicated thermal efficiency. At a 100% load, D70B30 (70% diesel + 30% biodiesel), D70B25BU5 (70% diesel + 25% biodiesel + 5%N-butanol), D70B20BU10, and D70B10BU20 exhibited 4.76%, 5.75%, 6.79%, and 8.71% higher indicated thermal efficiency values than D100 (100% diesel), respectively. The introduction of butanol enhanced the combustion environment within the combustion chamber. Compared with pure diesel, all blended fuels reduced hydrocarbon and carbon monoxide emissions across various loads. The blended fuels showed significant reductions in hydrocarbon emissions of 1%, 4%, 6%, and 15% compared with that of diesel under the 25% load, respectively.

The effects of limonene and eugenol additives in n-heptane and low-octane gasoline on the emission characteristics and fuel consumption of single-cylinder gasoline engine

This study investigated the effects of two additive polarities: polar (eugenol) and nonpolar (limonene) additives blended into n-heptane and low-octane gasoline. These compounds were chosen due to their unique molecular structure characteristics which influences the exhaust emissions. The physicochemical properties, fuel consumption, and exhaust gas emissions of a single-cylinder gasoline engine were measured. Four fuel blends were created by blending eugenol and limonene on a volumetric basis, n-heptane-eugenol (NHE), n-heptane-limonene (NHL), low-octane gasoline-eugenol (GE), and low-octane gasoline-limonene (GL). Tests were conducted on a single-cylinder gasoline engine. The exhaust gas emissions were analyzed using gas chromatography, and the role of each additive substance in the formation of carbon monoxide (CO), unburned hydrocarbon (HC), residual oxygen (O2), and carbon dioxide (CO2) emissions was validated using Hyperchem simulation and gas chromatography mass spectrometry. Owing to differences in the molecular structure and energy content of the two additives, the fuel consumption of NHE-fueled vehicles increased by 19.69% compared to NHL, whereas GE decreased by 32.15% compared to GL. Owing to the presence of oxygen atoms and low binding energy, blending eugenol with n-heptane and low-octane gasoline significantly reduced CO by 1.87% higher than limonene. However, eugenol’s aromatic structure can only reduce 14.45% of HC emission, while limonene, with its dynamically moving electrons and nonpolar properties can reduce up to 18.24%. It was discovered that the two additives could improve the quality of exhaust gas emissions.

Emission performance evaluation of urban passenger car fleet through field investigation data in a megacity.

Continued improvements in living standards and the economic well-being in the megacities have led to a huge surge in vehicular density. The worst environmental outcome of the same has been persistent unsafe urban air quality, thanks to vehicular emission. Further, the existing inspection and maintenance programs, conceived to check such emission remain largely ineffective, particularly in developing countries. This is due to the absence of a thorough assessment of the vehicle's compliance with the in-use emission norms generated through reliable field investigation data. To address this gap, the present comprehensive study collected real-time tailpipe emission data from 2040 cars in Delhi, India. Exhaust emission parameters, namely, CO (carbon monoxide), HC (hydrocarbon), and SE (smoke emission), were recorded from both petrol and diesel-driven cars of private ownership, in collaboration with the emission compliance test centers. The performance of cars was assessed in terms of their compliance with the in-use BS (Bharat Stage) emission norms. The one-of-its-kind study reported the petrol cars to be highly compliant toward the BS IV norm while faring even better toward BS II for both CO and HC emissions (80-90%). The conformance to the HC norm was found to be typically better than that for CO (85-90% versus 75-80%). For the diesel-driven cars, BS III compliance levels were reported relatively better compared to BS IV (90% in the case of the former against 80% in the latter's case). Further, the study puts forward a clear indication that the in-use emission norm and maintenance status of cars have a direct and negative relationship with tailpipe emission parameters. Cars of both overseas and domestic origin have almost equal degrees of compliance with the emission norms (over 80% in any case). The study recommends the incorporation of these two critical vehicular variables, i.e., maintenance status and in-use emission standard in the emission certification policy.

Production of low emission briquettes from carbonized faecal sludge as an alternative source of cooking energy

BackgroundIn Tanzania, firewood, charcoal, and agricultural waste play a crucial role in daily life as sources of cooking energy, especially in rural areas. Using these energy sources contributes to deforestation and the emission of harmful substances, leading to health problems. This study highlights the potential of faecal sludge briquettes as an innovative, environmentally friendly, and sustainable alternative to traditional energy sources to meet the increasing demand for cooking energy in Tanzania. The process involved sludge characterization, drying, sorting, carbonization, milling, briquette making, and characterization.ResultsA study was conducted to assess the presence of zinc (Zn), cadmium (Cd), and lead (Pb) in faecal sludge collected from households. The results indicates that the levels of these metals were all within the acceptable limits set by the Tanzanian Standards (TZS) for sludge disposal and use in the environment, which are 5.00 mg/L, 5.00 mg/L, and 30.00 mg/L, respectively. Septic tanks and pit latrines sludge had a concentration of 0.5 mg/L and 0.5 mg/L for Zn, 0.55 mg/L, and 0.6 mg/L for Cd, and 10.01 mg/L and 4.87 mg/L for Pb, respectively. Adding 75% charcoal dust improved the gross and net heating values from 10.47 and 10.16 to 19.29 and 18.86 MJ/kg, respectively. Similarly, adding 50% charcoal dust improved the gross and net heating values to 19.24 and 18.78 MJ/kg. The emission of particulate matter (micrograms/m3) was reduced from 30.4 and 35 to 10.3 and 11.8 for PM2.5 and 7 and 8 for PM10, while carbon monoxide emission decreased from 51.2 to 19.7 ppm.ConclusionThe results strongly suggest that briquettes made of carbonized faecal sludge mixed with other biomass materials could offer an alternative to traditional solid fuels, with the added benefits of reducing greenhouse gas emissions, deforestation, and longer burning times.

Design and optimization of a combined heat and power system with a fluidized-bed combustor and stirling engine

In this study, a fluidized-bed biofuel system was integrated with a Stirling engine (SE) to create a combined heat and power (CHP) system with high energy efficiency. Methods for ensuring the stability of the SE and fluidized-bed combustion were investigated and implemented. The proposed design was tested experimentally, and the system successfully produced electricity from the heat of the flue gas generated during biomass combustion. The Taguchi method was employed to maximize the temperature of the fluidized bed by modifying three parameters: the sand height, air flow rate, and biomass feed rate. The biomass used in this study was discarded mushroom sawdust waste. The biomass feed rate was varied from 9.5 to 17 g/min, and the air flow rate was varied from 50 to 60 L/min. The integrated CHP system was found to yield 90−100 W of electric power and 1077.3 W of heat energy for producing hot water. The oxygen, carbon dioxide, carbon monoxide, and nitric oxide concentrations of the flue gas produced under the optimized system parameters were analyzed, and minimal emissions of carbon monoxide and nitric oxides, which are harmful gases, were discovered. In most experiments on SEs in the literature, liquid or gaseous fuels have been used to power the engine. However, this study successfully used solid biomass fuel to power a practical SE, thus widening the knowledge on the utilization of this renewable energy source for electricity generation. The results of this study indicate that the proposed CHP system is stable, clean, and efficient. This system potentially provides a solution for two problems, namely the disposal of mushroom sawdust waste and the eco-friendly generation of heat and electricity. Therefore, the proposed system is promising for green and sustainable power generation in the future.

Heterogeneous ensemble prediction model of CO emission concentration in municipal solid waste incineration process using virtual data and real data hybrid-driven

Carbon monoxide (CO) is a hazardous gas discharged during municipal solid waste incineration (MSWI). Its emission concentration serves as a vital indicator for assessing the stability of the MSWI process. Therefore, accurate prediction of CO emissions is crucial. While existing research predominantly relies on historical real data-driven models, it often overlooks the effective utilization of the combustion mechanism. This article introduced a novel approach: a heterogeneous ensemble prediction model that integrates virtual and real data. Firstly, virtual mechanism data was obtained through a multi-condition mechanism model constructed using coupled numerical simulation software of FLIC and Aspen Plus. Secondly, based on this virtual mechanism data, a linear regression decision tree (LRDT) algorithm was employed to establish the mechanism mapping model. Simultaneously, a real historical data-driven model based on a long short-term memory (LSTM) neural network algorithm was developed. In the offline training verification phase, the heterogeneous models were combined using an inequality-constrained random weighted neural network (CIRWNN) after aligning virtual and real samples representing operating conditions based on the k-nearest neighbor (KNN) approach. Subsequently, in the online testing verification stage, CO online prediction was achieved by ensemble the LRDT-based mechanism mapping model and.the LSTM-based historical data-driven model. The proposed method's effectiveness and rationality were validated through an industrial case study of MSWI process in Beijing.

Predicting the effects of direct-injected fuels co-powered by high-CO2 biogas on RCCI engine emissions using kinetic mechanisms and multi-objective optimization

High inert gas content in biogas resulted in poor burning and emissions attributes, though scarcely investigated in reactivity controlled compression ignition (RCCI). Established kinetic mechanisms were combined with multi-objective optimization to investigate, predict, and analyze emissions occurrence and trade-offs for reduced environmental impacts. The work examined the impact of direct-injected high reactivity fuels (HRF) and port-injected Biogas at various inert gas (carbon dioxide, CO2) rates (25 – 45% vol), biogas fractions (40 – 70%), speeds (1600 – 2000 rpm), and loads (4.5 – 6.5 bar IMEP) on emissions of RCCI engine, experimentally. The findings revealed that while engine speeds greatly decreased CO (carbon monoxide) and NOx (nitrate oxide) emissions with rising unburned hydrocarbon (UHC) regardless of HRF employed, higher engine load significantly reduced UHC emissions. Diesel-biogas reduces NOx emissions and performs better in reducing CO and UHC emissions at lower speeds than B5-biogas, except in low-level loads. Although increasing CO2 impact led to a reduction in UHC and CO emissions, the biogas proportion was the most significant variable. The main factor influencing increased NOx emissions was engine load, which is inversely correlated with reduced NOx and increased particulate emissions owing to high CO2 content and biogas proportion. The premixed mode's optimisation outcome confirms the trade-off reduction at 5.5 bar IMEP, 35.586% CO2, and 50% fraction. As a result, running the RCCI engine with direct-injected diesel co-powered in equal proportion with high-CO2 biogas cuts the emissions trade-off dramatically, limiting the environmental repercussions of the emissions.

Biogas intake pressure and port air swirl optimization to enhance the diesel RCCI engine characteristics for low environmental emissions

Exhaust emission and combustion control in RCCI (reactivity-controlled compression ignition) focused mainly on the direct-injected fuel parameters, urging to investigate the advantages of port-fuel intake parameters. The engine was modified for port injection of Biogas at the valve and RCCI mode. The influence of port swirl ratio (PSR, 0 – 80%) and biogas injection pressure (BIP, 1 – 4 bar) on the diesel RCCI combustion and emissions was tested and optimized at varied loads and 1600 rpm in a port injection at the valve (PIVE) approach. Established kinetic mechanisms were combined with multi-objective optimization to further investigate, predict, and analyze emissions occurrence and trade-offs for reduced environmental impacts. The results show that the radiation absorption triggered by increased CO2 lowers combustion temperature, resulting in prolonged ignition. Setting the airflow to swirl lowers the in-cylinder pressure at elevated BIP while raising the heat generated across the BIPs. Increasing the PSR slows the combustion while BIP speeds up the process. BIP and PSR show great trade-off reduction ability among all emission parameters. The optimum unburned hydrocarbon, nitrogen oxide, particulate, and carbon monoxide emissions for the injection at the valve were found to be 109.58, 0.577, and 2.336 ppm, and 0.103%, respectively, at low-load, low-BIP, and high-PSR. The emissions were lowered by 6.58, 91.26, 80.65, and 13.45% compared to the premixed RCCI mode, respectively. Therefore, introducing low-pressure biogas amid high swirling air at the valve elevates the in-cylinder condition while lowering the emissions, mitigating their environmental implications.

Improving the performance of gasoline fuels by adding methanol and methyl tertiary-butyl ether along with metal oxides titanium oxide and magnesium oxide

These variables include the type of nanoparticle additives integrated into the fuel blend and the operational engine speed. The focus is on two specific oxygenated additives, methanol and isobutanol, in conjunction with Methyl Tertiary-Butyl Ether (MTBE) and two metal oxide nanoparticles, namely magnesium oxide and titanium oxide. The experimental framework entails testing these new fuel blends in a controlled environment, utilizing a four-stroke engine linked to a dynamometer and a speed analyzer. The tests are conducted at rotational speeds of 750 and 1250 rpm. The comprehensive data collected encompass a range of parameters, including engine power and torque, as well as the emissions of carbon dioxide (CO2), nitrogen oxides (NOx), unburned hydrocarbons (HC), and carbon monoxide (CO). The study meticulously analyzes data to build a robust model, significantly enhancing engine performance while substantially lowering emissions. It finds that adding specific additives to gasoline notably reduces carbon monoxide and hydrocarbons. Testing gasoline with methanol, MTBE, and titanium oxide at 750 RPM showed a notable shift in emissions: nitrogen oxide increased by 40.5%, while hydrocarbons, CO, and CO2 saw reductions of 17.5%, and from 2.4% to 7.8%–1.197% and 7.661%, respectively, underlining the need for careful fuel composition management for environmental benefits.

EFFECT OF RESIDENTIAL STOVE TECHNOLOGY ON GASEOUS EMISSIONS FROM BIOMASS COMBUSTION

The growing use of biomass for cooking and heating raises environmental concerns about atmospheric air pollution from flue gases emitting during its combustion. In this work, the gaseous emissions from two residential wood stoves were examined. Emissions from conventional single-stage and triple-stage combustion logwood stoves were compared using Eucalyptus grandis (EUG) and Pinus elliottii (PIE) woods as fuels. Carbon monoxide emissions were reduced in 102% and 240%, when PIE and EUG wood logs were burned in triple-stage combustion stove. The triple combustion system showed total volatile organic compounds and formaldehyde emissions higher than obtained in conventional system possibly due to the mixture of both gaseous emissions with water vapor releasing during combustion. The results indicated that the utilization of triple combustion stove with some adjustments would be beneficial to local air quality, individual health and reduced global climate change.

Enhancing biodiesel stability and performance: synthesis and extraction of macauba biodiesel for sustainable engine applications

The demand for sustainable fuels has driven research on biodiesel blends’ combustion characteristics and emissions. The study evaluates the performance of macauba and soybean biodiesel blends by analyzing torque, power, and fuel consumption indicators. The effects of leaf extract additives on engine performance are also assessed. Comparing macauba and soybean blends show similar load, brake power, and engine speed trends on response variables. However, slight variations in coefficients and significance levels indicate unique combustion and emission profiles for each blend. Understanding these distinctions is crucial for optimizing engine performance and emission control strategies. Parameters analyzed include brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust gas temperature (EGT), carbon monoxide (CO) emissions, hydrocarbon (HC) emissions, oxides of nitrogen (NOx) emissions, smoke opacity, cylinder pressure, heat release rate, and ignition delay. Blends 80% Soy Methyl and 20% Macauba Methyl Biodiesel (BSM20) demonstrates 5–10% superior fuel efficiency, 8–12% higher energy conversion capability, 3–5% lower exhaust temperatures, 10–15% reduced emissions, and 5–8% enhanced efficiency versus other blends and Diesel. It also shows 10–20% lower hydrocarbon and CO emissions, 15–25% reduced NOx, 20–30% lower particulate matter, and more efficient energy release during combustion. Optimizing heat release rate and ignition delay is crucial; BSM20 shows a 10–15% shorter ignition delay. Understanding blend distinctions is key for optimizing performance and emissions. BSM20 blend demonstrates superior fuel efficiency, energy conversion capability, lower exhaust gas temperatures, reduced emissions, and enhanced engine efficiency compared to other blends and Diesel. It also shows lower hydrocarbon, CO, and NOx emissions, reduced particulate matter emissions, and more efficient energy release during combustion. Optimizing heat release rate and ignition delay is crucial for cleaner combustion and improved engine performance.

Identifying the key atmospheric and economic drivers of global carbon monoxide emission transfers

ABSTRACT This paper proposes a structural decomposition analysis (SDA) augmented with cross-country atmospheric circulation and uncovers that changes in carbon monoxide (CO) levels are driven by atmospheric flows way more than by any of the traditional SDA components. Applied to a five-region model, our results show, among others, that South Korea has certainly been able to reduce the CO emissions in its own territory by 0.8Tg over 1990–2014 but up to 10.6Tg of CO flowing to its borders came from its upwind neighbor China. That amount was primarily driven by activities satisfying the growth of China's domestic demand, although changes in foreign demand and in the technology effect were not negligible. By quantifying the role of upwind countries in air pollution changes, our methodology allows us to identify more comprehensive global emission abatement policies than the consumer- or producer-focused approaches currently used.

Effect of Alumina and Bio‐Based Calcium Oxide Nanoadditives on Reduction of Emissions and Performance Improvement in a Common Rail Direct Injection Diesel Engine Fueled with B20 Blend of Waste Cooking Oil Biodiesel

This experimental study investigates the performance, combustion, and emission characteristics of a common rail direct injection diesel engine running on used cooking biodiesel prepared through transesterification. The nanoparticles calcium oxide (CaO) and alumina (Al2O3) are mixed with the B20 blend using an ultrasonicator to create a homogeneous mixture. The following five fuel series are used in the study: a B20 blend with three different nanoparticle ppms are blended to form Al2O3CaO 90 ppm, Al2O3 + CaO 60 ppm, and Al2O3 + CaO 30 ppm. The enhanced surface area to volume ratio of nanoparticles enhances the degree of mixing and chemical reactivity during combustion. Also, the characteristics of diesel engines result in reduced specific fuel consumption. The test fuel B20 + 90 ppm (90 ppm nanoparticles dispersion) results 9% and 11% increase in brake thermal efficiency compared to diesel and B20, respectively. The presence of nanoparticles in biodiesel has initiated the combustion slightly earlier due to its improved ignition qualities that permit catalytic combustion and a shorter ignition delay. In comparison to diesel and B20, the Al2O3CaO90 ppm fuel blend lowers NOx emissions by 18% and 21%, carbon monoxide emissions by 40% and 43%, hydrocarbon emissions by 35% and 40%, and smoke emissions by 24% and 29%, respectively.

Estimation and Analysis of Air Pollutant Emissions from On-Road Vehicles in Changzhou, China

Vehicle emissions have become a significant contributor to urban air pollution. However, studies specific to city-level vehicle emission inventories are still scarce and tend to be outdated. This study introduces a methodology for developing high-resolution monthly vehicle emission inventories. We applied this methodology to Changzhou in 2022 to analyze emission characteristics and generate gridded emission data with a resolution of 0.01° × 0.01°. The results show that the total vehicle emissions of carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), and fine particulate matters (PM2.5) in Changzhou are 39.69, 8.68, 18.6, and 0.56 Gg, respectively. Light-duty passenger vehicles are the main contributors to CO (74.3%) and VOCs (86.1%) emissions, while heavy-duty trucks play a significant role in NOx (50.7%) and PM2.5 (34.7%) emissions. Gasoline vehicles are mainly responsible for CO (78.6%) and VOCs (91.4%) emissions, while diesel vehicles are the primary source of NOx (81.1%) and PM2.5 (70.6%) emissions. Notably, China IV vehicles have the highest emission contribution rates (ranging from 32.5% to 44.9%). Seasonally, emissions peak in winter and are lowest in April. Spatially, emission intensity is higher in the northeast of Changzhou compared to the west and south. The methodology presented in this study offers a valuable tool for developing comprehensive city-level emission inventories, and the results provide critical insights that can inform the formulation of effective environmental policies.

Constraining the gas mass of Herbig disks using CO isotopologues

Context. The total disk mass sets the formation potential for exoplanets. Obtaining the disk mass is however not an easy feat, as one needs to consider the optical thickness, temperature, photodissociation, and freeze-out of potential mass tracers. Carbon-monoxide (CO) has been used as a gas mass tracer in T Tauri disks, but was found to be less abundant than expected due to the freeze-out and chemical conversion of CO on the surfaces of cold dust grains. The disks around more massive intermediate mass pre-main sequence stars called Herbig disks are likely to be warmer, allowing for the possibility of using CO as a more effective total gas mass tracer. Aims. This work aims to obtain the gas mass and size of Herbig disks observed with ALMA and compare these to previous works on T Tauri disks and debris disks. Methods. Using ALMA archival data and new NOEMA data of 12CO, 13CO, and C 18O transitions of 35 Herbig disks within 450 pc, the masses were determined using the thermo-chemical code Dust And Lines (DALI). A grid of models was run spanning five orders of magnitude in disk mass, for which the model CO line luminosities could be linked to the observed luminosities. Survival analysis was used to obtain cumulative distributions of the resulting disk masses. These were compared with dust masses from previous work to obtain gas-to-dust ratios for each disk. In addition, radii for all three isotopologues were obtained. Results. The majority of Herbig disks for which 13CO and C18O were detected are optically thick in both. For these disks, the line flux essentially only traces the disk size and only lower limits to the mass can be obtained. Computing the gas mass using a simple optically thin relation between line flux and column density results in an underestimate of the gas mass of at least an order of magnitude compared to the masses obtained with DALI. The inferred gas masses with DALI are consistent with a gas-to-dust ratio of at least 100. These gas-to-dust ratios are two orders of magnitude higher compared to those found for T Tauri disks using similar techniques, even over multiple orders of magnitude in dust mass, illustrating the importance of the chemical conversion of CO in colder T Tauri disks. Similar high gas-to-dust ratios are found for Herbig group I and II disks. Since group II disks have dust masses comparable to T Tauri disks, their higher CO gas masses illustrate the determining role of temperature. Compared to debris disks, Herbig disks have gas masses higher by four orders of magnitude. At least one Herbig disk, HD 163296, has a detected molecular disk wind, but our investigation has not turned up other detections of the CO disk wind in spite of similar sensitivities. Conclusions. Herbig disks are consistent with a gas-to-dust ratio of at least 100 over multiple orders of magnitude in dust mass. This indicates a fundamental difference between CO emission from Herbig disks and T Tauri disks, which is likely linked to the warmer temperature of the Herbig disks.

КАЧЕСТВО ВОЗДУХА В МОСКВЕ ВО ВРЕМЯ КАРАНТИНА COVID-19 В СРАВНЕНИИ С ДРУГИМИ РЕГИОНАМИ МИРА

An analysis of the changes in the carbon monoxide (CO) and particulate matter (PM10) mass concentrations in the atmosphere near highways and residential areas over Moscow during the spring lockdown in 2020 against of the mass concentrations in the previous years (2015-2019) is presented. In the lockdown period, a decrease in the CO mass concentrations was about 40% near highways and only 10% in residential areas. A decrease in the PM10 mass concentrations by about 10% was found during that period. The closeness of lockdown effects in Moscow and other megacities is shown by the comparison of trends in the traffic intensity and pollutant mass concentrations. The special importance of motor vehicles as a source of carbon monoxide emissions in the analyzed megacities is demonstrated.

Experimental and cfd analysis of the influence of fuel injection timing on the behavior of a gasohol-based gdi engine

ABSTRACT This work examines the impact of FIT (Fuel Injection Timing) on engine’s performance of an automotive, Gasoline Direct Injection (GDI) engine using Gasohol (85% Gasoline + 15% Ethanol by mass) as fuel. The start of FIT was experimentally varied from −280 CAD (Crank Angle Degrees) to −330 CAD at 10 CAD intervals by using an open ECU. Experiments were performed at variable power outputs (such as 5, 8, 10, 13, 16, 18 and 21 kW) at a constant speed of 2500 rpm. CFD simulations were carried out for the above said conditions to understand engine’s behavior. Considering the conventional start of injection, advancing the FIT showed improvement the BTE (brake thermal efficiency) up to −320 CAD BTDC. The maximum BTE was observed as 31.8% at the engine power output of 21 kW (whereas it was 28.6% at −300°CAD). CFD results confirmed the improvement in the air-fuel mixing rate and swirl motion. With the use of advanced FITs, the emissions of carbon monoxide (CO) and hydrocarbons (HC) were decreased. The CFD emission results for CO and HC showed good agreement with the experimental findings. With the advanced FITs, NOx emissions showed an increase at all loads. The in cylinder pressure was observed to be higher with advanced FITs. Modeling results are very well supported with experimental pressures. It is concluded that advancing the fuel injection timing might improve the performance and lower HC and CO emissions of a Gasohol-based GDI engine. The optimized injection timing of −320 CAD could be recommended for the aforementioned engine’s greatest performance.

Regional sources of NH3, SO2 and CO in the Third Pole

The Third Pole (TP) is a high mountain region in the world, and is well-known for its pristine environment, but recent development activities in the region have degraded its air quality. Here, we investigate the spatial and temporal changes of the air pollutants ammonia (NH₃), sulphur dioxide (SO₂) and carbon monoxide (CO) in TP, and reveal their sources using satellite measurements and emission inventory. We observe a clear seasonal cycle of NH3 in TP, with high values in summer and low values in winter. The intense agriculture activities in the southern TP are the cause of high NH₃ (6–8 × 1016 molec./cm2) there. Similarly, CO shows a distinct seasonal cycle with high values in spring in the southeast TP due to biomass burning. In addition, the eastern boundary of TP in the Sichuan and Qinghai provinces also show high values of CO (about 1.5 × 1018 mol/cm2), primarily owing to the industrial activities. There is no seasonal cycle found for SO₂ distribution in TP, but relatively high values (8–10 mg/m2) are observed in its eastern boundary. The high-altitude pristine regions of inner TP are also getting polluted because of increased human activities in and around TP, as we estimate positive trends in CO (0.5–1.5 × 1016 mol/cm2/yr) there. In addition, positive trends are also found in NH₃ (0.025 × 1016 molec./cm2/yr) during 2008–2020 in most regions of TP and SO₂ (about 0.25–0.75 mg/m2/yr) in the Sichuan and Qinghai region during 2000–2020. As revealed by the emission inventory, there are high anthropogenic emissions of NH3, SO2 and CO within TP. There are emissions of pollutants from energy sectors, oil and refinery, agriculture waste burning and manure management within TP. These anthropogenic activities accelerate the ongoing development in TP, but severely erode its environment.

Chemical reactor network modeling in the context of solid fuel combustion under oxy-fuel atmospheres

A multi-phase chemical reactor network (CRN) is developed and applied to investigate solid fuel combustion under oxy-fuel atmospheres in a laboratory-scale combustion chamber. The development of a novel solid-gas plug flow reactor (sPFR) allows the full coupling of solid and gas phase processes to increase the fidelity in CRN modeling. Together with the recently developed solid-gas perfectly stirred reactor (sPSR), the new sPFR is applied within a multi-phase reactor network to model the complex features of the investigated application. To design an initial reactor network, a hybrid experimental and computational fluid dynamics (CFD)-driven approach is being pursued, taking into account both global and local information on flow and temperature fields. Initially, an in-depth investigation of the physical processes is conducted, covering solid fuel conversion processes such as devolatilization and char conversion, along with the thermochemical characteristics of the flue gas. In particular, the prediction of carbon monoxide (CO) emissions is analyzed in detail by means of sensitivity analyses. Based on the findings of the sensitivity study, the network complexity of the initial reactor network is increased to enable an accurate prediction of the CO formation in comparison to the experiments. Finally, the formation of nitric oxides (NOx), sulfur oxides (SOx), and aromatic pollutants is discussed, highlighting the importance of detailed chemistry in solid fuel combustion at technically relevant scales.

Costs of Coal Abatement for Residential Heating to Reduce Urban Air Pollution in Asian Russia: Evidence from Krasnoyarsk

Heat and electricity generation are major sources of air pollution in many large cities worldwide. In Siberian cities, the heat supply significantly contributes to air pollution, as coal remains the primary energy fuel in most of Asian Russia. Krasnoyarsk, the second-largest city in the macro-region by population, serves as a clear example of urban air pollution. In recent years, public authorities have implemented several measures to reduce pollutant emissions. These measures include modernizing thermal power stations, replacing inefficient small boiler houses, and converting residential heating to more environmentally friendly types of fuel. However, our analysis shows that these policies have not yet resulted in a significant transition away from using coal for heating. One of the primary reasons is that alternative fuels are unable to compete with coal in terms of price. The proposal suggests transitioning private households to pellet heating. Our goal is to evaluate the potential environmental and economic impacts of this measure. We estimate the necessary subsidy size for the successful implementation of both initiatives. In conclusion, converting households from coal to pellet heating can reduce the emissions of nitrogen oxides, carbon monoxide, sulfur oxides, and suspended particles by 0.2%, 8.5%, 4.4%, and 2.7%, respectively, of the total pollutant emissions in Krasnoyarsk. Furthermore, this conversion can provide economic benefits by supporting local pellet producers who heavily rely on export markets. If practically implemented, the proposed approach could solve one of the most significant development issues of one of the largest Russian cities within a few years, with only 2.5% of the annual city budget expenditure.