Average NOx Emission Research Articles

Study on combustion and emission characteristics of hydrogen/air mixtures in a constant volume combustion bomb

Hydrogen is an environmentally-friendly fuel with the characteristics of low carbon, high calorific value, and extensive combustible range, making it an optimal alternative fuel for internal combustion engines. In this study, an experiment using a spherical constant volume combustion bomb (CVCB) was conducted to investigate the combustion and emission characteristics of hydrogen/air mixtures. The results shows that the flame propagation velocity of hydrogen laminar flow initially increases and then decreases with the excess air coefficient (λ), reaching peak at λ = 0.6, and the flame becomes unstable on the side of lean burning (λ > 1.0). Both the NOx emissions and the average temperature in the CVCB initially rise before eventually declining with the λ, the peak values for both NOx emission and mean temperature are reached at λ = 1.0. The dilution of N2 inhibits the laminar combustion and emission of hydrogen. As the dilution rate of N2 increases, little change occurs in the Markstein length, while flame propagation velocity, NOx emission, and average temperature all decrease. An increase in initial pressure hinders the development of the initial flame, while promoting the formation of cellular structure within the flame. Consequently, unstable combustion leads to a rapid increase in flame propagation speed during later stages. The average temperature inside the CVCB and the NOx emission increase by 6.6 % and 25.9 %, respectively, with the initial pressure increasing from 0.1 MPa to 0.5 MPa. On the other hand, an increase in initial temperature can facilitate flame development and results in an increased flame propagation speed. Especially, Markstein length is less sensitive to changes in initial temperature than to changes in initial pressure. The average temperature and NOx emission present a pattern of increasing first and decreasing then with the increase in initial temperature. These results have provided empirical evidence for optimizing the combustion and emission control of hydrogen engines.

Mathematical modeling and model predictive control research on coal powder burners for aggregate dryers

Aggregate drying is a crucial step in asphalt mixture production. Enhancing the model accuracy and controller performance of aggregate dryer burners is essential for consistent flame characteristics, reducing NOx emissions, and minimizing fuel consumption. This paper introduces a second-order nonlinear parametric model for coal powder burners that includes delay and noise. Model parameters were determined through experimental data using the Salp Swarm Algorithm, showing higher accuracy than models based on the least square method. A dual-layer model predictive control (MPC) based on this mathematical model was developed to improve the economic efficiency of the aggregate drying process. Simulation results showed that the dual-layer MPC saves 1.08 tons of coal every 10 h compared to a standard MPC. A full-scale prototype demonstrated average flame length, flame temperature, and NOx emissions of 4242.6 mm, 1729.4 °C, and 460.2 mg/m³, respectively, validating the accuracy of the proposed mathematical model and controller.

Enhancing diesel engine efficiency and emission performance through oxygenated and non-oxygenated additives: A comparative study of alcohol and cycloalkane impacts on diesel-biodiesel blends

This study evaluates the impact of renewable fuel additives on diesel engine performance, combustion, and emissions. Safflower seed oil was converted into biodiesel (BD) through transesterification, achieving a 94.12 % conversion yield, verified by spectroscopic analysis. Test fuels were prepared by adding 5 %, 15 %, and 25 % n-pentanol (PE, oxygenated) and cyclohexane (CHx, non-oxygenated) to diesel fuel (DF) and BD. These blends were tested in a single-cylinder diesel engine under varying loads. At maximum load, BSFC values were 0.251 for DF, 0.333 for 25 % PE, and 0.269 kg/kWh for 25 % CHx. BTE values were 32.184 % for DF, 27.028 % for 25 % PE, and 31.147 % for 25 % CHx. The peak in-cylinder pressure and net heat release for the 25 % PE blend, which were the highest among the test fuels, were 58.148 bar and 37.010 J/°CA, respectively. Average NOx emissions were 171 for DF, 135.75 for 25 % PE, and 170.50 ppm for 25 % CHx. CO emissions were 171 for DF, 149.25 for 25 % PE, and 170.25 ppm for 25 % CHx. Smoke opacity values were 0.75 for DF, 0.308 for 25 % PE, and 0.675 m-1 for 25 % CHx. Despite higher costs, CHx offers reduced environmental impact without significantly compromising engine performance.

Retrofitting Natural Gas–Fired Boiler for Hydrogen Combustion: Operational Performance and NOx Emissions

Abstract The effects of hydrogen fraction (HF: volumetric fraction of H2 in the fuel mixture of CH4 + H2) from 0% to 100% by volume, on the thermal and environmental performance of a 207-MW industrial water tube boiler, are investigated numerically at a fixed excess air factor, λ = 1.15. This study aims to determine the hardware modifications required for boilers to be retrofitted for pure hydrogen operation and investigates how NOx emissions are affected by hydrogen enrichment. The results showed insignificant increases in maximum combustion temperature with increasing the HF, though the distributions of temperature profiles are distinct. In reference to the basic methane combustion, H2 flames resulted in a positive temperature rise in the vicinity of the burner. Increasing the HF from 0% to 2% resulted in higher average thermal NOx emissions at the boiler exit section from 37 up to 1284 ppm, then it decreased to 1136 ppm at HF = 30%, and later it leveled up to 1474 ppm at HF = 100%. The spots for higher differences in NO formation compared to the reference case are shifted downstream at higher HFs. The effect of hydrogen enrichment on CO2 and H2O as radiation sources, as well as the volumetric absorption radiation of the furnace wall and the heat flux at furnace surfaces, has all been presented in relation to the effect of hydrogen addition on boiler performance.

Experimental investigation of engine performance and emissions, and characterization, of waste transformer oils and diesel blends with biodiesel produced from olive oil wastes in a CI engine

In this study, five different fuel blends were prepared by mixing biodiesel obtained from olive oil wastes using transesterification method, waste transformer oil, and Euro diesel in different ratios. The important physicochemical properties of the prepared fuel blends and produced biodiesel were determined by gas chromatography, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential scanning calorimetry analyses, and their characterizations were carried out. Then, the effects of the prepared fuel blends on engine performance and emission characteristics were investigated in a compression ignition engine. The experiments were performed with five different fuel blends (TD30, TD30B10, TD30B20, TD30B30, and D100) at 1000, 1500, 2000, and 2500 rpm. At all speeds, each fuel blend produced an average torque value that was highest for D100 fuel and lowest for TD30 fuel The average BP value produced by each fuel at all engine speeds was highest in D100 fuel and lowest in TD30 fuel. The results of the experiments showed that there was a 23.98% decrease in the average NOx emissions of TD30 fuel blend compared to the average NOx emissions of D100 fuel at all engine speeds. It was observed that all important fuel properties such as density, kinematic viscosity, and pour and cloud points of all fuel blends met the fuel standards.

Experimental and Simulation Study on Ultra-Low NOx Emissions of Anthracite by Preheated Combustion

ABSTRACT In this study, the ultra-low NOx emission of anthracite was achieved by the preheated combustion technology. Meanwhile, the preheated combustion model was established using Aspen Plus. High-temperature preheating (above 950°C) improved the conversion process from fuel-nitrogen to N2 and precursor of NOx, which involved the cracking of N-5 and N-6. The conversion rate from fuel-nitrogen to N2 was 81.88%. In addition, heterogeneous reduction reaction of NOx was the critical conversion path of fuel-nitrogen for the ultra-low NOx emission during the combustion. The conversion rate from NOx to N2 was 0.43%. The average NOx emission of tail flue gas was 40.77 mg/m3 and 46.15 mg/m3 (@6%O2) for Jincheng anthracite and Yangquan anthracite, respectively. The simulation results showed that the preheated combustion model demonstrated precise prediction capabilities for containing-nitrogen gas emission. The maximum error of NOx emission and N2 concentration were 7.71% and 3.37%, respectively. The simulation and experimental results could be mutually verified.

Experimental investigation and optimization of dual fuel combustion using diesel/gasoline and Bio-oil extracted from Co-thermal liquefaction of paint/biomass wastes: An approach towards waste to energy

A higher-grade transport fuel from both non-biodegradable paint waste and biomass plant Prosopis Juliflora is obtained in the most economical and eco-friendly way by hydrothermal liquefaction process. The yielded bio-oil is experimented on a diesel engine in dual fuel combustion (DFC) strategy and compared with the conventional diesel combustion (CDC). In DFC, the secondary fuels (gasoline, bio-oil, and premixed gasoline-bio-oil blends) are port injected at different premixed ratios (10, 20 and 30%), while the primary diesel fuel is directly injected into the cylinder. DFC of diesel - bio-oil (DB) exhibited higher brake thermal efficiency than premixed gasoline at all power outputs and performed closer to neat diesel. Lower smoke emission is observed in DB than neat diesel and the DFC of diesel-gasoline (DG) at all conditions. At 30% premixed ratio, the smoke opacity of DFC of diesel and premixed bio-oil - gasoline (DGB) is 65.7% and 68% respectively compared to that of CDC (76.4%). At all loads, average NOx emission of DGB (20% gasoline) is abated by 23.2, 7.8 and 12.9% than CDC and 20% of DB and DG respectively but almost equal to neat diesel at full load. The experimental data are used to train an artificial network (ANN) and the trained ANN is used to generate sufficient data for optimizing the fuel concentration using TOPSIS algorithm to realize an overall improved performance and emissions. The optimized combustion modes arrived from this study are: CDC for 25% load, DFC of DGB (D90G2B8) for 50% load and DFC of DB for 75% (D89B11) and 100% (D86B14) loads.

Influence of phenolic antioxidant additives on performance and emission characteristics of diesel engine fuelled with Jatropha biodiesel: A sustainable hybrid model using RSM and ANFIS

This study aimed to assess the inclusion of antioxidant diphenylamine (DPA) to a Jatropha biodiesel (B30) blend to affects engine performance and exhaust emissions. In this research, three fuel blends has been utilized: diesel, B30, and 100 ppm of antioxidant diphenylamine is added to the B30 blend referred to as B30 + DPA100. A Response Surface Methodology (RSM) has been employed to analyze experimental data, resulting in the development of a regression equation. Additionally, an Adaptive Neuro-Fuzzy Inference System (ANFIS) has been employed to assess and verify the consistency of the developed model. The results from the experiments revealed that the inclusion of the antioxidant had a notable impact on reducing NOx emissions with only a slight effect on brake thermal efficiency (BTHE). Specifically, B30 + DPA100 showed a 7.48 and 15.53% decrease in average NOx emissions, while the average BTHE experienced a modest 0.78% decrease and a 2.67% increase compared to diesel and B30 biodiesel blend, respectively. The Brake Mean Effective Pressure (BMEP) of B30 + DPA100 has been found to be 3.91% and 1.3% higher than diesel and B30, respectively. The Brake Specific Fuel Consumption (BSFC) was 8.68% lower than B30 but 1.49% higher than diesel. Overall, these findings suggest that B30 + DPA100 can be used in diesel engines without modification, offering reduced NOx emissions.

The reaction characteristics and mechanism of polymer non-catalytic reduction (PNCR) for NOx removal

To overcome the defects of the traditional selective non-catalytic reduction (SNCR) process (e.g., low efficiency, narrow temperature range), a new modified SNCR technology based on the solid complex polymer reducing agents, also called polymer non-catalytic reduction (PNCR), was investigated both in the laboratory and pilot scale to reveal its reaction characteristics and mechanism. The PNCR process demonstrates excellent removal efficiency (about 90%) of NO in furnace in the wide temperature range (850–1150 °C), and possesses promising application feasibility with an average NOx emission concentration of 68.72 mg·m−3 even on unstable industrial operating conditions. The NO removal behaviors influenced by O2, temperature, or water steam illuminate the unique O2-independent and H2O-promoted reaction characteristics of PNCR in the wide temperature range. The thermogravimetric infrared spectra/mass spectrometry (TG-IR/MS) results further reveal a pyrolysis-assisted formation mechanism of active NH2/NH free radicals without the requirement of O2 and high temperature, which avoids the overoxidation of active radicals and accounts for the wide denitrification temperature window, low oxygen compliance and high denitrification efficiency of PNCR process. The excellent NO removal performance as well as the unique reaction characteristics/mechanism of PNCR forebode its broad industrial application prospect in the field of flue gas cleaning.

Comparison and testing of cerium oxide nanoparticle added Pongamia and, Scenedesmus microalgae biodiesel blends

The demands for alternative fuel sources rapidly riring due to depleting fossil fuel sources and severe environmental impacts of using them aggressively. The current study investigates and compares the performance of the third generation Scenedesmus sp. and second generation Pongamia blended biodiesels and the impacts of mixing cerium oxide (CeO2) nanoadditives on the performace and emission charactestics. Enriched percentage of biodiesel: thirty percent blended biodiesels of Scenedesmus sp. (A30), Pongamia (P30), 100 ppm CeO2 nanoparticles in A30 (A30C100), and 100 ppm CeO2 nanoparticles in P30 (P30C100) are experimentally tested in an indirect injection CI engine. Nanoparticle addition to Scenedesmus sp. and Pongamia biodiesel blends improved the engine average brake thermal efficiency (BTE) by 4.2% and 3.8% respectively. The peak pressures are found to be the highest for nanoparticle-added blends and their peak heat release rates are slightly shifted from the top dead center. The A30 and P30 NOx emissions are found to be lower than the diesel, addition of nanoparticles increased the NOx emission level by 2.17% and 6.17% respectively. The average NOx emission of P30C100 is found even higher than diesel. Smoke emissions of all biodiesel variants tested in the current study are found to be significantly lower than diesel. The addition of CeO2 nanoparticles helped in improving the performance of blended biodiesel and reducing the smoke emissions of an engine. Scenedesmus biodiesel-nanoparticle blend (A30C100) achieved BTE close to diesel at higher loads and it is recommended as a better alternative fuel for CI engines. The findings of the current study will help in exploring the ways of shifting from B20 to B30 in many fleet and commerical vehicles.

Development of a new premixed burner for biomass gasifier generated low calorific value producer gas for industrial applications

The present paper deals with the design of an efficient premix burner design for low calorific value producer gas as a fuel. The proposed premix and the existing available conventional burner are tested and operated on a 10 kg/h capacity downdraft gasifier with garden waste feed. The premix burner (PB) has dual slits swirl vane for air-fuel mixing along with a bluff body each at an angle of 32° and 45°, designed based on simulation results from numerical simulations. Its performance is compared with a conventional burner (CB). Flame temperature variation at different axial and radial distance for both the burners was studied. Flame temperature variation with λ (Ratio of actual air/fuel by stoichiometric air/fuel) are determined. The average NOx and CO emissions for PB are found to be 55% and 70% lower than the CB under nearly identical conditions. PM10 and PM2.5 particulate matter emissions are 65% lower in PB than CB during a stable flame time (15–120 min). The thermal efficiency for PB mode was 55% and that for CB it was 26%. PB showed a better flame stability, higher flame temperatures, lower emissions and higher thermal efficiency as compared to the CB.

Effect of the hydrogen/kerosene blend on the combustion characteristics and pollutant emissions in a mini jet engine under CDC conditions

In this CFD study conducted with the geometry of a mini gas turbine engine using kerosene as fuel, colorless distributed combustion conditions were achieved by increasing the N2 ratio in the air. Then, H2 was added to the kerosene fuel in order to increase the combustion performance and the combustion chamber temperature distributions, NOx, CO, and CO2 values were examined. In the simulations using the simplified GTM-120 geometry, the combustion chamber outlet temperatures at 80 k, 100 k, and 120 k rpm were compared with the experimental results in the literature by changing the ratio of fuel and air for the validation study. Standard k-ε and Discrete Ordinates were chosen for turbulence and radiation models, respectively. In the study conducted with the non-premixed combustion model, simulations were made at O2 rates of 21%, 19%, 17%, and 15% for the formation of colorless distributed combustion conditions. For enrichment with hydrogen, H2 was added from 0% to 50% with 10% increments. HEF (Hydrogen energy fraction) has been used as the hydrogen addition rate. In light of the analyses made, it was seen that the colorless distributed combustion regime reduced the flame temperature from 2292 K to 1912 K and the NOx amount from 2.85 ppm to 0.0086 ppm. On the other hand, it is seen that this regime increased the CO emissions from 6.9 ppm to 38.67 ppm and the mole ratio of CO2 from 6.25% to 6.94%. It was observed that these findings prepared the ground for increasing the amount of hydrogen in the fuel, which increases the flame temperature and, accordingly, NOx emissions. By adding 50% H2 to kerosene under standard atmospheric conditions, the average NOx emission at the combustion chamber outlet increased from 2.85 ppm to 7.97 ppm, while the average CO emission decreased from 6.9 ppm to 1.08 ppm. As a matter of fact, by the addition of 50% H2 to the kerosene with air that contains 15% O2, which is the most extreme combustion situation in this study, the flame temperature decreased to 1912 K, and NOx rose to 0.0713 ppm. However, the CO emissions at the combustion chamber outlet decreased to 1.83 ppm and the CO2 ratio to 3.48%. Thus, with this study, it has become possible to use hydrogen as an alternative fuel in a real engine geometry by using CDC and hydrogen enrichment together, both in terms of pollutant emissions and combustion performance.

Analysis of cruise conditions on energy, exergy and NOx emission parameters of a turbofan engine for middle-range aircraft

Studying efficiency and emissions of an aircraft engine at cruise phase is of high importance so as to help in finding optimum flight conditions. Especially, since exhaust emissions from the engine lead to climate change, quantifying exhaust emissions could show adverse effect of the aero-engine on environment. In this study, energetic and exergetic behaviour of high by-pass turbofan are parametrically examined. Besides, cruise NOx emission is measured by P3-T3, Boeing Fuel Flow Method 2 (BFFM2) and DLR methods. Moreover, the index as Specific NOx Production (SNP) is quantified for the turbofan engine. Thanks to this parameter, NOx effect of the engine is compared according to different flight conditions. For this aim, parametric cycle equations and emission calculation methods regarding turbofan engine are encoded so as to determine performance outputs for Mach changing from 0.7 to 0.9 and altitude between 9000 m and 11,000 m. According to performance results, the average specific fuel consumption (SFC) regarding turbofan engine is predicted as 19.65 g/kN.s at 9 km and 19.68 g/kN.s at 11 km. As for exergo-sustainability index, environmental effect factor is calculated as 1.19 at 9 km and 1.26 at 11 km. Also, the average cruise NOx emission index is found as 16.66 g/kg at 9 km and 13.93 g/kg at 11 km. Finally, the mean SNP regarding the turbofan is measured as 0.5071 g/kN.s at 9 km and 0.3374 g/kN.s at 11 km. The findings of this study provide useful insights to comprehend effects of flight conditions on aircraft emissions. In terms of environmental sustainability, decision mechanism could be enhanced to find out optimum flight conditions thanks to the presented results.

Long term (2005–2016) study of formaldehyde (HCHO) columns from satellite data in two regions in the south of Mexico. Evidence of the impact of agricultural activity

In order to determine the driver factors and the principal months of enhancement of HCHO over the Oaxaca and the Chiapas regions, important agricultural areas located in the south of Mexico, HCHO columns from the Ozone Monitoring Instrument (OMI) were monthly averaged (HCHOOMI) and used in conjunction with monthly averaged isoprene emissions (isoprene), monthly NOx emissions from biomass burning (NOx_bb), and monthly averaged NOx emissions from soils with their different sources (biomes: NOx_bio, fertilization and manure: NOx_fer, deposition of N: NOx_dep, pulses: NOx_pul, and total: NOx_tot) from January 2005 to December 2016. Based on scatterplots grouped by month due to the seasonality of the variables, Spearman rank correlations, and multiple linear regression models, we determined that isoprene was an important driver of HCHOOMI in the Oaxaca region, contributing both to its seasonality and peak presence during April and May; whereas NOx_bb was a relevant source in the enhancement of HCHOOMI during April and May, months in which the fire season occurs in the south of Mexico. In the Chiapas region, we determined that both isoprene and NOx_fer were important drivers of the seasonality of HCHOOMI and its peak months during April and May. NOx_bb was predominantly involved in the HCHOOMI enhancement during April and May. The overall multiple linear regression model for each study region was significant (F-statistic = 21.35, p<0.0001 for the Oaxaca region; F-statistic = 101.59, p<0.0001 for the Chiapas region) and explained 72% of the variation of HCHOOMI in the Oaxaca region, 85% in the Chiapas region. Based on the multiple linear regression model for each study region, monthly averaged modeled HCHO columns (HCHOMOD) were obtained. With the estimated regression coefficients, the contribution (in %) of the relevant emission fluxes for each region were calculated in order to know which source was the predominant one in the exacerbation of HCHOMOD. During the peak months of HCHOMOD (April and May) in the Oaxaca region, isoprene predominates over NOx_bb. In the Chiapas region both NOx_bb and NOx_fer caused the exacerbation of HCHOMOD during April and May, whereas NOx_fer was the major variable that caused the increase of HCHOMOD during June, July, and August, especially from 2014 to 2016. Overall, in this region the emissions of NOx were more important in the increase of HCHOMOD than isoprene. NOx_bb and NOx_fer were enhanced principally due to the agricultural activity taking place in the Oaxaca and Chiapas regions. Thus, this work demonstrates the impact of agricultural activity on HCHO columns observed by the OMI instrument. In addition, this work shows that HCHO columns can be modeled using HCHO columns obtained from satellite data and emission inventories. The analysis performed here can be applied to other similar regions not only in Mexico but elsewhere around the world.

A fuel-consumption based window method for PEMS NOx emission calculation of heavy-duty diesel vehicles: Method description and case demonstration

Due to the lack of engine reference torque and the accumulated work of reference transient cycle, the work based window (WBW) method for portable emission measurement system test data processing cannot be used for vehicle emission assessment in the current on-board diagnostics (OBD) system in China. In this work, a fuel-consumption based window (FBW) method was proposed to imitate a WBW method procedure by using fuel consumption rate as an alternative parameter to scale the window so the entire procedure can be based on the attainable data items in the OBD system. Some key issues regarding converting WBW method to FBW method, including window separation, window average power ratio calculation and specific NOx emission conversion from mg/kg. fuel to mg/kW.h, were solved by linking the 100-km fuel consumption and the average vehicle specific power of China World Transient Vehicle Cycle test. The comparison between the FBW and WBW methods on the NOx emission calculation results shows that the number of all windows, the number of valid windows, and the thresholds for >50% valid windows are quite similar for WBW and FBW methods. The estimation accuracy of average power ratio for the FBW method depends on the value of transmission efficiency of vehicle driveline. The deviations of 90% specific NOx emission in mg/kW.h between the two methods are smaller than 6% for the cases investigated in the present work.

Evaluation of Greenhouse Gas Emission Levels during the Combustion of Selected Types of Agricultural Biomass

This paper presents the results of an experimental study of the emission levels of selected greenhouse gases (CO2, CH4, NOx) arising from the combustion of different forms of biomass, i.e., solid biomass in the form of pellets and liquid biomass in the example of engine biofuel (biodiesel). Both types of biomass under study are rape-based biofuels. The pellets are made from rape straw, which, as a waste product, can be used for energy purposes. Additionally, biodiesel contains rape oil methyl esters (FAME) designed to power diesel engines. The boiler 25 kW was used to burn the pellets. Engine measurements were performed on a dynamometer bench on an S-4003 tractor engine. An analyzer Testo 350 was used to analyze the exhaust gas. CO2 emission studies do not indicate the environmental benefits of using any alternative fuels tested compared to their conventional counterparts. In both the engine and boiler tests for NOx emissions, no environmental benefits were demonstrated from the use of alternative fuels. The measured average NOx emission levels for biodiesel compared to diesel were about 20% higher, and for rapeseed straw pellets, they were more than 60% higher compared to wood pellets. Only in the case of engine tests was significantly lower CH4 (approx. 30%) emission found when feeding the engine with rape oil methyl esters.

Low NOX and high organic compound emissions from oilfield pumpjack engines

We measured a comprehensive suite of pollutants emitted from 58 natural gas-fueled pumpjack engines in Utah’s Uinta Basin. Air–fuel equivalence ratio (the ratio of air taken in by the engine to the amount of air needed for combustion of the fuel) was a strong predictor of emissions. Higher air–fuel equivalence ratios led to lower oxides of nitrogen (NOX) emissions and higher emissions of organic compounds. For engines with air–fuel equivalence ratios greater than 3 (34% of 58 total engines tested), a median of 57% of the fuel gas passed through the engine uncombusted, and exhaust gas contained a median of only 3 ppm NOX. Lower air–fuel equivalence ratios were associated with less fuel slip, higher NOX, and the formation of more reactive organic compounds, including alkenes and carbonyls. Average NOX emissions measured in this study were only 9% of average emissions from natural gas-fueled pumpjack engines in a regulatory oil and gas emissions inventory. In contrast, volatile organic compound emissions in the study were 15 times higher than in the inventory. We hypothesize that these discrepancies are due to changes in emissions as engines operate at lower loads and as they age in field conditions. In addition to improving emissions inventories and the effectiveness of related regulatory efforts, this work will improve the ability of photochemical models to simulate the atmospheric impacts of oil and gas development.

Influence of multiple gaseous medium injection on low-carbon iron ore sintering performance: Characteristics of natural gas and steam coupling injection

Hydrogen-rich gas and steam are widely regarded to be of great potential to mitigate CO2 emissions in iron ore sintering, these gases can regulate heat distribution in the sintering machines by replacing fossil fuels. However, most sintering machines only use one of the gases as the injecting medium, the potential of this technology has not been developed. In this paper, a multiple gaseous medium injection method contained natural gas and steam was experimentally investigated to solving this problem. Sintering tests were arranged to study the appropriate scheme of coupling injection and its influence on the sintering process, and the flue gas analyzer was used to detect the composition of the sintering flue gas in real time. Better sintering indexes were achieved by injecting the above two gaseous medium when the coke breeze ratio is unchanged, the results show that when 0.8 vol% natural gas is injected into the 4–14min, 0.15 vol% steam is injected into the 10–14 min, and 0.25 vol% steam is injected into the 15–18 min of sintering, the sintering yield increases by 2.42%, and the tumbler index increases by 2.72%. Under the above parameters, the coke breeze ratio can be reduced by 12.99%, the average NOx emissions decreased by 19.5%, and the average CO emissions decreased by 36.96% in the coupling injection interval (4–18min). After calculating the amount of coke breeze and natural gas in the optimal coupling injection sintering, CO2 emissions decreased by 7.66%, about 17.15 kg/t-sinter. Moreover, the PFR model was used to simulate the associated gas phase reaction after coupling injection which shows H2O significantly reduced CO emissions and change the reduction pathway of NO. Generally, sintering fuel consumption and greenhouse gas emissions have also been reduced, providing theoretical support for the change of iron ore sintering energy structure.

Assessing heavy-duty vehicles (HDVs) on-road NOx emission in China from on-board diagnostics (OBD) remote report data

Mobile source emissions are some of the major causes of air pollution across the world and are associated with numerous adverse health impacts. China has implemented increasingly stringent emission standards over the past few decades, the most recent one being the sixth emission standard (China VI) first rolled out in 2019. The China VI standard places special emphasis on tightening limits for NOx emission and introduces remote monitoring of vehicles' On-board diagnostics (OBD) data to reduce emissions from diesel and gas-powered heavy-duty vehicles (HDV).This paper aims to establish a methodology to calculate HDV NOx emissions on an extended timescale, and under real-world operations. OBD data was collected and examined from 53 China VI diesel HDVs and 14 China V diesel HDVs, which found that the average NOx emission factors are 1.420 g/km and 3.894 g/km for the two samples respectively; this indicates that the implementation of China VI standard helps to significantly reduce NOx emission from HDVs. Combining the emission factors and calculated travel distances collected by OBD and vehicle sales data, the China VI emission standard is estimated to have resulted in 43,969 tons of NOx emission reduction by the end of 2020. With China announcing country-wide enforcement of the new standard in 2021, >1.7 million tons of NOx emission could be avoided by 2023 annually.

Laboratory and Field Performance of Two In-House Developed Metal Biomass Cookstoves

Present work reports thermal and emission performance of in-house developed natural and forced draft metal biomass cookstoves. Laboratory as well as field tests are performed on the cookstoves. Experiments are performed on natural draft metal cookstove in laboratory at different air supply hole openings. Decrease in average input power and average thermal efficiency is observed between 3.74-3.43 kW and 31.14-29.45% respectively. Variation in average emission factor for carbon monoxide (CO) is found to be between 3.5-9.9 g/MJd. Emissions of Oxides of Nitrogen (NOx) are found to be varying between 1 ppm to 13.5 ppm without any specific trend. Experiments are performed on forced draft metal cookstove in laboratory on two fan speeds. The average input power and average thermal efficiency vary between 3.4-3.0 kW and 36.9-42.5% respectively. Variation in average emission factor for CO is found to be between 1.8-4.5 g/MJd and that of average NOx emissions between 16.8-2.5 ppm.During field tests, amount of fuel consumption and emissions of CO for both the cookstoves is compared with traditional cookstoves used by two families. In case of Family A, there is a saving in fuel consumption by 19% and 40% with natural draft and forced draft metal cookstoves respectively. The corresponding values for Family B are 5 % and 24% respectively. In case of Family A, there is decrease in CO emissions by 89% and 86% with natural draft and forced draft metal cookstoves respectively. The corresponding values for Family B are 76% and 82% respectively.