Pollutant Emission Characteristics Research Articles

Study on The Test Methods of Heavy Metal in Exhaust Gas for a Copper Melting Factory

The raw materials, auxiliary materials and production process of a typical copper smelting factory were investigated, the emission characteristics of exhaust gas pollutants produced by the production process were studied. To test the samples by graphite furnace, firstly in order to unify the digestion system in the experiment, the applicability of three different method was verified by experiments. According to the results, the recovery of nitric acid-perchloric acid digestion system is a relatively good, so it can be recommended. The testing results show linear range, detection limit and detectability of the method could meet the requirements of environmental monitoring.

Effect of Hydrogen Content on Pollutant Emissions and Combustion Characteristics of a Methane-Hydrogen Mixture Fueled Multi-Nozzles Array Model Combustor

Effect of Hydrogen Content on Pollutant Emissions and Combustion Characteristics of a Methane-Hydrogen Mixture Fueled Multi-Nozzles Array Model Combustor

Multi-point access to urban underground road longitudinal ventilation system operation control method

While the multi-point access to urban underground roads solve traffic congestion, the pollutants (CO, NOx, etc.) emitted during tunnel travel also pose environmental and health risks to the tunnel drivers and passengers as well as the residents near the tunnel openings. To this end, this study focuses on the environmental safety of urban underground roads with multiple points of entry and exit as the focus of research, based on the law of conservation of mass, fluid dynamics and ventilation engineering theory and simulation of experimental research methods, combined with motor traffic and pollutant (CO, NOx, etc.) emission characteristics, proposed NO concentration prediction model, combined with the urban underground road air flow and ventilation system operating characteristics, the longitudinal distribution law of pollutant concentration along the tunnel is calculated through case analysis, the intelligent control strategy of the ventilation system is proposed. The results show that when the traffic flow reaches 2000veh·h-1, two fans need to be started, and the power consumption is 50% less than that of the whole fan. It is expected to provide a reference basis for the design and efficient low-carbon operation of ventilation system design for urban underground roads with complex structures.

Multi-factor reconciliation of discrepancies in ozone-precursor sensitivity retrieved from observation- and emission-based models.

Ground-level O3 pollution has been continuously worsening in China despite gradual improvement in other major pollutant levels. Understanding the sensitivity of O3 production to its precursors (OPS) is a prerequisite for formulating effective O3 control measures, but this has been hampered by significant discrepancies in OPS produced by traditional identification approaches using observation-based models (OBM) and emission-based models (EBM). In this study, by applying OBM and EBM in parallel within a month having significant O3 pollution in Shanghai, China, we demonstrated that a lack of carbonyl input, overestimation in NO2 monitoring data, and differences in simulation period and emission reduction area were the core factors leading to OPS discrepancies, and that a reliable OPS cannot be obtained unless these factors are reconciled. By collectively addressing these factors, the number of days with a consistent OPS from both models increased from 6-7 to 20-21 in a month, and the R value defined to quantify the discrepancy decreased by ∼55%. The contributions of these factors to OPS discrepancy differed greatly in urban and suburban settings, mainly caused by differences in pollutant emission and transport characteristics. Overall, OPS identified solely by OBM or EBM is associated with great uncertainty, while reliable OPS estimation can be achieved by a collective application of OBM and EBM with consensus on the above factors. The method demonstrated here could be applied to other photo-chemically active regions worldwide as part of efforts to address ozone pollution.

Effects of road slope on emission characteristics for a heavy-duty diesel vehicle based on engine-in-the-loop methodology

A dump truck with a maximum designed total mass of 24500 kg was selected to measure the emission characteristics of pollutants and carbon dioxide (CO2) under fully-loaded and unloaded conditions at the same simulated road with different road slope, same driver and vehicle model by using the engine-inthe- loop methodology. The results show that driving at gradient road will result in an increase in power and total emissions. The brake specific emissions of gaseous pollutant and CO2 are lower at gradient road, while the brake emission of particle number are higher at gradient road. Road slope affects exhaust temperature so as to affect nitrogen oxide (NOx) emissions. Under unloaded conditions, long-slope conditions are more likely to cause an increase in NOx emissions.

СНИЖЕНИЕ ВЫБРОСОВ ЗАГРЯЗНЯЮЩИХ ВЕЩЕСТВ УХОДЯЩИХ ГАЗОВ ТЕПЛОЭЛЕКТРОЦЕНТРАЛЕЙ

This paper considers the characteristics of a thermal power plant as a major source of air pollution in the city of Omsk, considers the sources and composition of exhaust gases, qualitative and quantitative characteristics of pollutant emissions, and presents a technological scheme for the formation of these components. Based on the results of the work, measures were proposed to reduce the negative impact of exhaust gases on atmospheric air, and 2 technological installations for cleaning exhaust gas emissions were considered in comparison, and the environmental and economic effect was calculated.

Investigation of the pollutant emission characteristics of blends of biomass and coal gangue in a fluidized bed

The composite fuel of coal gangue and biomass is expected to increase the utilization rate of solid waste and compensate for the disadvantages of separate fuels. However, the NO and SO2 emissions from this composite fuel during the combustion process are a concern, but there are few studies on it. In this paper, corn cobs and wheat straws, typical agricultural biomass discarded in North China, and coal gangue from the mine in Xilingol, China, were selected for co-combustion in a fluidized bed. The emission characteristics of NO and SO2 were studied by changing the ratio of biomass to coal gangue and the combustion temperature. Studies had shown that: to a certain extent, mixing biomass, and coal gangue can reduce the NO and SO2 emissions, and mixing 20% of biomasses had the best effect on NO and SO2 emissions reduction. The SO2 emission reduction effect of wheat straws was better than that of corn cobs, and the NO emission reduction effect of corn cobs was better than that of wheat straws. The NO emissions of wheat straws and corn cobs added to the coal gangue were 6.45% and 7.93% less than those of coal gangue alone. The SO2 emissions of wheat straws and corn cobs added to the coal gangue were 27.45% and 25.94% less than those of coal gangue alone. Both NO and SO2 emissions decreased with the growth of the biomass rate; NO and SO2 emissions increased with the growth of the combustion temperature.

Real driving energy consumption and CO2 & pollutant emission characteristics of a parallel plug-in hybrid electric vehicle under different propulsion modes

PHEVs (Plug-in hybrid electric vehicles) are thought to be energy and environment friendly, while these conclusions are seldom verified during real driving tests. To evaluate PHEV real driving energy consumption, CO2 emission, and pollutants emission, one parallel PHEV was tested under real driving condition. The results indicate that the distance-specific energy consumption of CD (charge depleting) mode, compared with the CS (charge sustaining) mode, is 45% lower for WTW (Well to Wheel) evaluation. The CD WTW CO2 emission is 50% higher than the CS due to the electricity generation CO2 intensity. CD and CS mode could have similar CO2 emission when electricity CO2 intensity reaches 397.50 g/kWh. The limited charging reduced the PHEV energy conservation by around 50%, but the WTW CO2 emission is also reduced. Contrary to common belief, the PHEV CD mode real driving emission is underestimated, and it could be over 30 times higher than the CS mode. The deteriorated CD emission is caused by the inaccurate power demand prejudgments and frequent engine cold high-power re-start. The driving pattern comparison reveals that the deteriorated CD emission should not be a local but global concern. These results could be used for PHEV propulsion strategy optimization and test cycle design.

Synergistic effect, kinetics, and pollutant emission characteristics of co-combustion of polymer-containing oily sludge and cornstalk using TGA and fixed-bed reactor

The synergistic effect of co-combustion of polymer-containing oily sludge (POS) and cornstalk (CS) was investigated by thermogravimetric analyzer (TGA) and fixed-bed reactor. The TGA results show that the co-combustion process of POS-CS can be divided into three stages: the evaporation of the oil-water, combustion of volatiles and light oil, and the coupled combustion of heavy oil, fixed carbon, and organic matter. With CS ratios from 30% to 70%, the ignition index and comprehensive combustion index of POS increase by 1.18–2.33 times and 1.53 to 3.95 times, respectively. The POS-CS blends have an inhibitory effect in the temperature range of 180–260 °C and 420–495 °C, however, a synergistic effect is exhibited throughout the entire temperature range. The activation energies of the blends are 33%, 45%, 41%, 35% and 53% lower than that of POS, at the CS ratios of 30%, 40%, 50%, 60% and 70%, respectively. The fixed-bed experiments indicate that the emissions of NO and SO2 decrease with the increase of CS. Specifically, the NO and SO2 emissions of the blend with CS ratio of 70% are 2.86 mg g−1 and 3.49 mg g−1, which decrease by 31.6% and 37.8%, compared with POS, respectively. In addition, the pollutant level (NO and SO2) of POS-CS blends is also lower than some typical solid fuels.

Research on Combustion Properties and Pollutant Emission Characteristics of Blends of Maltol Byproduct/Pine Sawdust.

In this paper, the combustion and pollutant emission characteristics of maltol byproduct, pine sawdust, and their blends were experimentally studied by thermogravimetry, tube furnace experiment, and scanning electron microscopy. The results show that the combustion process of maltol byproduct, pine sawdust, and their blends can be divided into three stages, in which the volatile release of the maltol byproduct includes two stages. The ignition temperature of the blended fuel is lower than that of sawdust. The NOx produced by combustion of the blended fuel is lower than that produced by sawdust combustion alone, and the SO2 emission is always at a low level. There is a certain synergy between maltol byproduct and pine sawdust mixed combustion. Comprehensively comparing the combustion characteristics and emission characteristics, the blended fuel made by adding less than 10% maltol byproduct into pine sawdust can improve the combustion characteristics and reduce emissions, and 10% is the best proportion of the blended fuel.

Introduction of IoT-Based Surrogate Parameters in the Ex-Post Countermeasure of Industrial Sectors in Integrated Permit Policy

New approaches and techniques are required for environmental management in workplaces that emit pollutants. The best available techniques (BATs) that are suggested by the integrated environmental permit system (IEPS) play a pivotal role in providing state-of-the-art approaches and techniques to workplaces. For the workplaces that install facilities with the BATs, it is necessary to perform real-time monitoring to determine whether pollutant emission facilities and treatment facilities are operating normally and whether such facilities can maintain the optimal condition during the emission of pollutants. The environmental management measures used before the IEPS had limitations for workplaces that are subjected to integrated environmental management because they consider the entire workplace as a single pollution source by combining all media. In addition, only the emission concentrations and amounts of pollutants were monitored because only the points at which most pollutants are discharged, i.e., stacks for air pollutant emission facilities and final effluent outlets for water pollutant emission facilities, are monitored. These monitoring approaches in a variety of facilities involve considerable costs, and most of them (95% for stacks in workplaces under IEPS, Korea) cannot perform real-time observation even though some of them are capable of it (5% for stacks managed by Tele Monitoring System, TMS). In this study, the applicability of a wireless sensor monitoring network was examined as a new approach for environmental management in workplaces. Based on the sensor monitoring network, surrogate parameters that can indirectly monitor the critical operating factors of pollutant emission and prevention facilities were developed and then measured in real time to examine the status of these facilities. Surrogate parameters can be used instead of directly measuring pollutants as the former has high efficiency, such as cost reduction, and can provide reliable data on the emission characteristics of pollutants. The wireless network is based on an Internet of Things (IoT) platform under real-time conditions in the emission and production facilities in a workplace. This study suggested that a wireless network using the IoT platform improves the BAT assessment methodology to understand the efficiency of environmental pollution reduction and the economic contribution to the workplace.

Uncovering the characteristics of air pollutants emission in industrial parks and analyzing emission reduction potential: case studies in Henan, China

Industrial parks contribute greatly to China’s economic development while emitting huge air pollutants. It is necessary to study the characteristics of air pollutant emissions in industrial parks. In this study, emission inventories for 11 industrial parks were established. Meanwhile, the source emission and spatial distribution characteristics of the industrial park were analyzed. The cluster analysis was used to classify these parks into “4Hs”, “Mixed” and “4Ls” parks. “4Hs”, “Mixed” and “4Ls” represent that the levels of energy intensity, economic proportion of energy-intensive industries, coal proportion and pollution performance value are high, medium and low in turn. Then three emission reduction measures were set up to estimate the emission reduction potential and environmental impacts. The results show that: (1) the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs and NH3 of 11 industrial parks in 2017 were 11.2, 23.1, 30.8, 8.3, 3.5, 5.1, and 1.1 kt, respectively. (2) Power plants were the largest source of SO2 and NOx emissions, and industrial processes were the largest emission source of CO, PM10, PM2.5, VOCs and NH3. (3) “4Hs” parks with traditional energy-intensive industries as the leading industries should be the emphasis of air pollutant emission reduction. (4) Through the optimal emission reduction measures, SO2, NOx, PM10, PM2.5 and VOCs were reduced by 81, 46, 51, 46 and 77%, respectively. Environmental impact reductions include 1.6 kt SO2eq acidified gas emissions, 1.4 kt PO43−eq eutrophication substances, 4.2 kt PM10eq atmospheric particulate emissions, 7.0 kt 1,4-DCEeq human toxic substances, and 5.2 kt PM2.5 eq breathing Inorganic. This study is helpful to understand the characteristics of air pollutants emissions in industrial parks and promotes the proposal and implementation of air pollutant emissions reduction strategies.

Health Risk Assessment of Toxic and Harmful Air Pollutants Discharged by a Petrochemical Company in the Beijing-Tianjin-Hebei Region of China

Monitoring of toxic and hazardous air pollutants (HAPs) in a petrochemical company in the Beijing-Tianjin-Hebei region of China to assess the impact of HAPs on the health risks of workers in the petrochemical company. The samples were tested by solid-phase adsorption thermal desorption/gas chromatography-mass spectrometry (HJ734-2014), and the pollutant emission list was obtained. According to the pollutant emission inventory, it can be seen that benzene, toluene and xylene are the main components of toxic and harmful air pollutants emitted by the petrochemical enterprise. The method of combining actual monitoring and CALPUFF model prediction was used to evaluate the impact of the toxic and harmful air pollutants emitted by the enterprise on the health of workers. The risk characterization results show that when benzene is the maximum concentration value predicted by the model, it will pose a carcinogenic risk to the factory workers. Therefore, based on the results of this study, it is recommended not to allow residents to live within the predicted concentration range of the model. The results of this study can enable China’s oil refining industry to better understand the characteristics of pollutant emissions from petrochemical companies in the Beijing-Tianjin-Hebei region. Moreover, the results of this study can be used as a policy basis for improving the health of workers in petrochemical enterprises, and are of great significance to the protection of public health.

Transformation of nitrogen during microalgae model compounds liquefaction in sub-/supercritical ethanol

Nitrogen migration significantly affects the quality of bio-oil and the emission characteristics of pollutants during microalgae thermochemical transformation. To investigate the nitrogen migration and transformation of the main components of microalgae during liquefaction in sub- or supercritical ethanol, three model compounds (soya protein, castor oil, and corn starch) were selected to explore the interaction among various biochemical components and organic solvent at 220 °C and 260 °C. The nitrogen contents in the products were accurately quantified and characterized by GC–MS, element analysis, XPS, and FTIR analysis. The results imply that the addition of castor oil has a negligible effect on the nitrogen transformation during liquefaction, while corn starch promotes more than 22.16 wt% of the nitrogen transfer into the solid residue. Pyrrolidinone is the main nitrogen-containing compound in the oil products; neither pyridine-N nor nitrile-N are detected. It indicates that the hydrogen supply of ethanol is also suitable for the addition of C-N unsaturated bonds in bio-oils. The model compounds containing corn starch generate pyrazines only at the higher temperature and pressure.

Experimental Investigation on the Heat Flux Distribution and Pollutant Emissions of Slot LPG/Air Premixed Impinging Flame Array

Experiments were carried out to investigate the heat transfer and pollutants emission characteristics of a slot LPG premixed flame array impinging normally onto a flat plate. The effects of jet-to-jet spacing (S/de), nozzle-to-plate distance (H/de), and jet Reynolds number (Re) on the heat flux and emission index of CO, CO2, and NOx/NO2 were examined. In addition, the thermal and emission characteristics between slot jets and circular jets were compared under identical experimental conditions. The results show that the more uniform heat flux distribution and higher total heat flux can be obtained at moderate jet-to-jet spacing, large jet-to-plate distance, and higher Reynolds number. EICO emissions can be influenced by the combined effects of jet-to-jet spacing, jet-to-plate distance, and higher Reynolds number. For the sake of the better combustion efficiency and lower EICO emission, the moderate jet-to-jet spacing (S/de = 2.5), larger jet-to-plate distance (H/de = 4), and relatively higher Reynolds number (Re = 1500) are preferred for the slot jet flame array. Furthermore, it is found that there exists a trade-off between the EICO and EINOx of the slot LPG flame array. Compared with multiple circular flame jets, multiple slot flames jets have the higher area-averaged heat flux due to the larger heating area and more uniform heat flux distribution, while the higher EICO emission and lower EINOx emission are due to the greater jet interaction suppressing the air entrainment. Thus, it is known that the slot flame array has a better heating performance but relatively higher pollutant emissions than the circular flame array.

Influence of Fuel Type and Water Content Variation on Pollutant Emission Characteristics of a Biomass Circulating Fluidized Bed Boiler

In general, the biomass raw materials burned by biomass power plants generally have the characteristics of variable fuel types, high moisture content, and high volatile content. In this paper, a 130 t/h biomass circulating fluidized bed (BCFB) model was established on the MWorks platform with Modelica language. The influence of biomass type changes on operation parameters, the corresponding steady-state characteristics, and the dynamic characteristics of the BCFB were carried out. The temperature corresponding to the combustion of pine was overall higher than that of the other fuels, and the flue gas from the combustion of pine had the highest concentration of SO2, up to 520.49 mg/Nm3. The flue gas from the combustion of pure cotton sticks had the highest concentration of NO, up to 254.34 mg/Nm3. The changes of fuel type and moisture content all have a great influence on the operation of BCFBs. The emission of pollutants was not only related to the element content of fuel, but also closely related to the furnace temperature. The fuel moisture content also indirectly affects the pollutant emission concentration and the steam-water system.

Emission inventory and control policy for non-road construction machinery in Tianjin.

The establishment of a non-road construction machinery emission inventory forms the basis for the analysis of pollutant emission characteristics and for the formulation of control policy. We analyzed and investigated data on populations, emission factors, and activity levels for the construction machinery in Tianjin to estimate an emission inventory. Finally, a variety of emission reduction scenarios were used to simulate emission reductions and propose the most effective control policy. The results show that total emissions of CO, HC, NOx, PM10, and PM2.5 from non-road construction machinery in Tianjin of 2018 reached 4180.78, 951.44, 5833.85, 383.92, and 365.70 t, respectively. Forklifts, excavators, and loaders were the three most important emission sources in Tianjin. There are clear differences in the emissions of different districts. Large machinery emissions were mainly distributed across the Binhai New Area, which includes high volumes of port machinery and tractors in Tianjin Port. Based on various emission reduction scenarios, the effect of emission reductions is estimated. The IAD affected the reduction of CO and HC emissions with RR values of 17.6% and 17.3%, respectively, while EMO affected the mitigation of PM10 and PM2.5 emissions and RR values by 18.0% and 18.4%, respectively. The emission reduction control policy for non-road construction machinery is proposed, including the accelerated updating of non-road machinery emission standards; integrating diesel engine research and development institutions to accelerate the development of vehicle after-treatment technology; and establishing a cooperation mechanism for scientific research institutes, government departments, and enterprises in the control of non-road mobile machinery emissions.

Investigation on combustion, gaseous pollutants emission and ash characteristics during co-combustion of semicoke and coal slime

Co-combustion of semicoke and coal slime is promising for their co-disposal. In this study, the co-combustion behaviors, interaction and gaseous pollutants emission of semicoke and coal slime were studied by thermogravimetric analyzer coupled with Fourier transform infrared spectrometer (TG-FTIR). The ash characteristics after co-combustion were also investigated. Results showed adding coal slime could improve the ignition and burnout performance of blends but lead to the declining comprehensive combustion index. Inhibitory effects were prominent at the early stage of co-combustion due to the heat competition while promoting effects existed in fixed carbon combustion. The ash accumulation suppressed co-combustion again at the burnout stage. Semicoke could reduce NO, NO2 and SO2 emission of blends but also cause serious slagging because of the high Ca content. Adding coal slime could prevent the generation of eutectics and thus decrease the ash slagging propensity of blends. The sulfur-retention reaction was more intense at coal slime blend ratio of 40%. Semicoke ash had higher Mn, Ni and Cu concentrations while coal slime ash has more Zn and Pb contents. With the increase of coal slime blend ratios, Mn, Ni and Cu in ash gradually decreased while Zn and Pb increased.

Emission Characteristics of Hazardous Air Pollutants from Medium-Duty Diesel Trucks Based on Driving Cycles

Studies on the characteristics of hazardous air pollutants (HAPs) in the emissions of medium-duty diesel trucks are significantly insufficient compared to those on heavy-duty trucks. This study investigated the characteristics of regulated pollutants and HAPs, such as volatile organic compounds (VOCs), aldehydes, and polycyclic aromatic hydrocarbons (PAHs), and estimated non-methane hydrocarbon (NMHC) speciation in the emissions of medium-duty diesel trucks. Ten medium-duty diesel trucks conforming to Euros 5 and 6 were tested for four various driving cycles (WLTC, NEDC, CVS-75, and NIER-9) using a chassis dynamometer. In an urban area such as Seoul, CO and NMHC emissions were increased because of its longer low-speed driving time. NOx emissions were the highest in the high-speed phase owing to the influence of thermal NOx. PM emissions were almost not emitted because of the DPF installation. Alkanes dominated non-methane volatile organic compound (NMVOC) emissions, 36–63% of which resulted from the low reaction of the diesel oxidation catalyst. Formaldehyde emissions were the highest for 35–53% among aldehydes irrespective of driving cycles. By sampling the particle-phase of PAHs, we detected benzo(k)fluoranthene and benzo(a)pyrene and estimated the concentrations of the gas-phase PAHs with models to obtain the total PAH concentrations. In the particle portion, benzo(k)fluoranthene and benzo(a)pyrene were over 69% and over 91%, respectively. The toxic equivalency quantities of benzo(k)fluoranthene and benzo(a)pyrene from NIER-9 (cold) for both Euro 5 and Euro 6 vehicles were more than five times higher than those of NIER (hot) and NEDC. In the case of NMHC speciation, formaldehyde emissions were the highest for 10–45% in all the driving cycles. Formaldehyde and benzene must be controlled in the emissions of medium-duty diesel trucks to reduce their health threats. The results of this study will aid in establishing a national emission inventory system for HAPs of mobile sources in Korea.

Anthropogenic emission inventory of multiple air pollutants and their spatiotemporal variations in 2017 for the Shandong Province, China

Shandong is the most populous and highly industrialized province in eastern China, and the resultant poor air quality is a cause for widespread concern. This study combines bottom–up and top–down approaches to develop a high-resolution anthropogenic emission inventory of air pollutants for 2017. The inventory was developed based on updated emission factors and detailed activity data. The emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter with aerodynamic diameters smaller than 2.5 and 10 μm (PM2.5 and PM10, respectively), carbon monoxide (CO), volatile organic compounds (VOCs), and ammonia (NH3) were estimated to be 1387.8, 2488.6, 5281.7, 3193.0, 9250.7, 2254.7, and 1210.6 kt, respectively. Power plants were the largest contributors of SO2 and NOx emissions accounting for 43.7% and 41.9% of the total emissions, respectively. CO emissions mainly originated from industrial processes (40.1%), mobile sources (24.8%), and fossil fuel burning (21.2%). The major sources of PM10 and PM2.5 emissions were industrial processes and fugitive dust, contributing 83.0% and 86.9% of their total emissions, respectively. Industrial processes (60.0%) contributed the largest VOC emissions, followed by mobile sources (16.8%) and solvent use (14.5%). Livestock and N-fertilizers were major emitters of NH3, accounting for 69.9% and 21.2% of the total emissions, respectively. Emissions were spatially allocated to grid cells with a resolution of 0.05 ° × 0.05 ° based on spatial surrogates, using Geographic Information System (GIS). Heavy pollutant emissions were mainly concentrated in the central and eastern areas of Shandong, while high NH3–emissions occurred in the western region. Most pollutant emissions from industrial sectors occurred in June and July, while low emissions were recorded between January and February. Range uncertainties in emission inventory were quantified using Monte Carlo simulations. Our inventory provides effective information to understand local pollutant emission characteristics, perform air quality simulations, and formulate pollution control measures.