Reduction Of SO2 Emissions Research Articles

Air pollution reduction and climate co-benefits in China’s industries

Air pollution reduction policies can simultaneously mitigate CO2 emissions in the industrial sector, but the extent of these co-benefits is understudied. We analyse the potential co-benefits for SO2, NOx, particulate matter (PM) and CO2 emission reduction in major industrial sectors in China. We construct and analyse a firm-level database covering nearly 80,000 observations and use scenario simulations to estimate the co-benefits. The findings show that substantial co-benefits could be achieved with three specific interventions. Energy intensity improvement can reduce SO2, NOx, PM and CO2 emissions for non-power sectors by 26–44%, 19–44%, 25–46% and 18–50%, respectively. Reductions from scale structure adjustment such as phasing out small firms and developing large ones can amount to 1–8%, 1–6%, 2–20% and 0.2–3%. Electrification can reduce emissions by 19–25%, 4–28%, 20–29% and 11–12% if the share of electricity generated from non-fossil fuel sources is 70%. Since firm heterogeneity is essential to realize the co-benefits and directly determines the magnitudes of these benefits, stricter and sensible environmental policies targeting industrial firms can accelerate China’s sustainable transformation.

Investigation of the Waste Heat Recovery and Pollutant Emission Reduction Potential in Graphitization Furnace

The graphite furnaces, which are extensively used for high-purity graphite production, inevitably discharges a large amount of waste heat that requires significant recovery for purpose of the improved energy efficiency. The paper numerically analyzed the heat transfer performance of a graphitization furnace under the electrical-heating and natural-cooling period. The temperature-dependent properties and heat transfer coefficients were used to predict the waste heat recovery potential along with on-site measurements. The results show that during the graphitization production, the core furnace temperature can reach 3000°C while the petroleum coke surface reaches 368°C without the combustion of the volatile in the coke. The heat dissipation on the top coke surface accounts for 48.5% of the total electricity input and 66.9% of the total heat dissipation from the furnace, respectively. The equivalent emission reduction of CO2 , SO2 and NO x are 47.5 t, 7.4 t and 3.6 t respectively per annum. The investigation of the waste heat recovery potential for graphite furnaces can provide a reference for the optimization of heat recovery equipment and operation for graphite furnaces.

Reduction of NOx and SO2 Emissions by Shore Power Adoption

Shore power systems, an alternative energy source to ships at berth, have the potential to improve air quality at ports and surrounding areas. This study assessed the reduction of four major air pollutants: PM10, PM2.5, NOx, and SO2, from adopting shore power at the Port of Kaohsiung. The reduction was assessed in two scenarios, S1 and S2, with a capacity to provide shore power to 342 and 780 ships at berth, respectively. The emissions from the ships were estimated based on the operation loads of the auxiliary engines, average time at berth, and emission factors. Additionally, the AERMOD model was used to simulate the ground-level dispersion of the four pollutants to the surrounding urban areas. The simulation results showed that the elevated areas in the city were vulnerable to ship emissions, especially for NOx. The maximum simulated contribution at ground level from S1 and S2 were 78.8 µg m–3 and 147 µg m–3 for NOx, and 20.1 µg m–3 and 42.5 µg m–3 for SO2, respectively; while the results for PM10 and PM2.5 were insignificant. The reduction benefit was then calculated as the ratio of the simulated air pollutant concentration to the observed concentration at the local air quality monitoring station. The highest reduction benefit of shore power adoption at the port was for NOx and SO2 emissions, with average reduction benefits of 8.70% ± 2.10% and 11.74% ± 2.95%, respectively. In conclusion, shore power adoption at the Port of Kaohsiung would greatly reduce air pollution in the port city, especially in residential areas, and be consider

Sulfur retention efficiency of clean coke produced by co-pyrolysis of coal with CaCO3 to substitute household coal

Raw coal is used by many suburban and rural households for cooking and heating and results in severe air pollution, especially problematic SO2 emissions. A source treatment strategy was proposed to reduce SO2 emissions, which used the co-pyrolysis of raw coal with a CaCO3 additive to produce clean coke. The effect of Ca/S molar ratio on the SO2 capture efficiency of clean coke was investigated, and the SO2 retention efficiency was optimized at a Ca/S molar ratio of 1.5. The sulfur retention mechanism of clean coke was attributed to: (1) CaCO3 decomposition to CaO and partial reaction of CaO with H2S to generate CaS during pyrolysis. (2) Transformation of the remaining sulfur in the clean coke to SO2 during combustion, capture by unreacted CaO to form CaSO4, and direct oxidation of CaS to CaSO4. The feasibility of SO2 emission reduction by clean coke in a practical household stove was verified.

Molecular Distributions of Diacids, Oxoacids, and α‐Dicarbonyls in Summer‐ and Winter‐Time Fine Aerosols From Tianjin, North China: Emissions From Combustion Sources and Aqueous Phase Secondary Formation

AbstractTo understand the characteristics and sources of organic aerosols (OA) in North China, we studied diacids, oxoacids, and α‐dicarbonyls in summer‐ and winter‐time fine aerosols (PM2.5) collected from Tianjin. Oxalic (C2) acid was found to be the most abundant diacid species, followed by succinic (C4), malonic (C3), and sebacic (C8) acids, respectively. Glyoxylic (ωC2) was the most abundant oxoacids followed by pyruvic acid. Concentrations of total diacids, oxoacids, and α‐dicarbonyls in winter were 2–3 times higher than those in summer, but their mass fractions in PM2.5 were exactly the opposite. On average, total diacids carbon accounted for 2.9% in total carbon and 3.3% in organic carbon (OC) in summer and 1.8% and 2.0%, respectively, in winter. Their contributions to water‐soluble OC (WSOC) was almost the same in both seasons (5.5% and 5.3%, respectively). Molecular distributions, mass ratios of selected diacid (C3, C4, M, F, C6, Ph, and C9) species, and the linear relations among the selected species (including ∑C2–C4 and ∑C8–C12) and with inorganic markers (K+ and SO42−) implied that the diacids and related compounds are mainly originated from coal combustion and biomass burning emissions and produced in the atmosphere by both in situ photochemical reactions at local scale and aging during long‐range transport in both summer and winter. This study revealed that diacids and related compounds and WSOC are increased with increasing SO42− and they are produced in the aqueous phase, implying that the reduction in NOx and SO2 emissions could possibly control the water‐soluble OA loading over North China.

Return to different climate states by reducing sulphate aerosols under future CO2 concentrations

It is generally believed that anthropogenic aerosols cool the atmosphere; therefore, they offset the global warming resulting from greenhouse gases to some extent. Reduction in sulphate, a primary anthropogenic aerosol, is necessary for mitigating air pollution, which causes atmospheric warming. Here, the changes in the surface air temperature under various anthropogenic emission amounts of sulphur dioxide (SO2), which is a precursor of sulphate aerosol, are simulated under both present and doubled carbon dioxide (CO2) concentrations with a climate model. No previous studies have conducted explicit experiments to estimate the temperature changes due to individual short-lived climate forcers (SLCFs) in different climate states with atmosphere–ocean coupled models. The simulation results clearly show that reducing SO2 emissions at high CO2 concentrations will significantly enhance atmospheric warming in comparison with that under the present CO2 concentration. In the high latitudes of the Northern Hemisphere, the temperature change that will occur when fuel SO2 emissions reach zero under a doubled CO2 concentration will be approximately 1.0 °C, while this value will be approximately 0.5 °C under the present state. This considerable difference can affect the discussion of the 1.5 °C/2 °C target in the Paris Agreement.

Application of BP neural network models in predicting the desulfurization rate of petroleum coke calcination flue gas

Sulfur-containing prebaked anodes, mainly made from petroleum coke, can give rise to SO2 emission in the production of electrolytic aluminum. In order to study the correlation between the emission volume and desulfurization rate of the flue gas discharged from the calcination of petroleum coke, a traditional double hidden layer BP neural network model was established on the basis of BP neural network by taking the emission data of the petroleum coke calcination flue gas desulfurization system as input parameters. This model was used to predict the desulfurization rate of the petroleum coke calcination flue gas desulfurization system, with an aim to control the SO2 removal rate of flue gas through controlling the flue gas parameters of the desulfurization system, so as to reduce SO2 emission from the flue gas of the electrolytic aluminum industry. The study will be of practical significance for the SO2 removal of the petroleum coke calcination flue gas.

Why sulfur dioxide emissions decline significantly from coal-fired power plants in China? Evidence from the desulfurated electricity pricing premium program

Sulfur dioxide (SO2) emissions from coal-fired power plants in China have declined significantly since an incentive-based policy named as the desulfurated electricity pricing premium program (DEPPP) was implemented for all coal-fired power plants in 2006. Using industrial pollution panel data from 350 prefectures in China and difference-in-differences models, we estimate causal effects of the DEPPP on the coal-fired power plants. We find that the DEPPP provided the coal-fired power plants strong incentives to invest in capital-intensive flue gas desulfurization (FGD) equipment and to operate the installed FGD at a higher rate, and thus contributed to significant reductions in total SO2 emissions in China. Our results suggest that the DEPPP reduced uncertainty faced by the coal-fired power plants when making large capital investments in SO2 abatement techniques such as FGD to comply with stringent environmental regulations. However, the DEPPP may not be cost-effective in reducing SO2 emissions given heterogeneous marginal costs for operating FGD units in different coal-fired power plants. Furthermore, the effectiveness of the DEPPP also depends on strengthened environmental regulatory capacities to enforce coal-fired power plants to comply with the operating rate requirement for the installed FGD.

Installment of desulfurization equipment at coal-fired power plants in North Carolina and associations with preterm birth among surrounding residents

Background: Coal-fired power plants (CFPPs) are major contributors of air pollution globally. In 2002, North Carolina (NC) adopted regulation that required CFPPs to substantially reduce their sulfur dioxide (SO2) emissions by 2013. CFPPs complying with this regulation have resulted in measurable decreases of ambient SO2 across NC. Air pollution research suggests an association between ambient SO2 and preterm birth (PTB, gestational age < 37 completed weeks). PTB is an important risk factor for neonatal mortality and associated with high healthcare costs. This study aims to evaluate the impact of SO2 emissions reduction strategies at CFPPs on preterm birth in North Carolina.Methods: The US Environmental Protection Agency’s Air Markets Program data were used to determine when the SO2 emissions reduction strategies were implemented at NC’s largest CFPPs (capacity > 150 megawatts). The study population was derived from geocoded NC resident singleton live birth data from 2003-2015 obtained from the NC State Center for Health Statistics. A difference-in-difference analysis using a linear mixed model with random intercepts for the CFPPs will be employed to compare the risk of PTB for mothers living 0-5 miles and 5-10 miles from the CFPPs before and after the intervention, with a control of mothers living 10-15 miles from the CFPPs.Results: During the study period, 7 CFPPs installed desulfurization equipment (i.e. SO2 scrubbers). The median concentration for reported monthly SO2 air emissions from the CFPPs in the pre-period and post-period were 4,421 tons and 281 tons, respectively. With the spatial and temporal exposure restrictions applied, there were 42,076 births within 15 miles of the CFPPs.Conclusions: This study comes at a time when the United States government is considering whether to move away from or reinvest in coal for electricity generation.

Minimal Climate Impacts From Short-Lived Climate Forcers Following Emission Reductions Related to the COVID-19 Pandemic.

We present an assessment of the impacts on atmospheric composition and radiative forcing of short‐lived pollutants following a worldwide decrease in anthropogenic activity and emissions comparable to what has occurred in response to the COVID‐19 pandemic, using the global composition‐climate model United Kingdom Chemistry and Aerosols Model (UKCA). Emission changes reduce tropospheric hydroxyl radical and ozone burdens, increasing methane lifetime. Reduced SO2 emissions and oxidizing capacity lead to a decrease in sulfate aerosol and increase in aerosol size, with accompanying reductions to cloud droplet concentration. However, large reductions in black carbon emissions increase aerosol albedo. Overall, the changes in ozone and aerosol direct effects (neglecting aerosol‐cloud interactions which were statistically insignificant but whose response warrants future investigation) yield a radiative forcing of −33 to −78 mWm−2. Upon cessation of emission reductions, the short‐lived climate forcers rapidly return to pre‐COVID levels; meaning, these changes are unlikely to have lasting impacts on climate assuming emissions return to pre‐intervention levels.

Pollution haven or halo? The role of the energy transition in the impact of FDI on SO2 emissions

This paper explores how the relationship between FDI and SO2 emissions has been affected by the energy transition. We applied a semi-parametric method to a STIRPAT model using Chinese provincial panel data from 2002 to 2016 to conduct an empirical analysis of FDI and SO2 emissions and analyze the effects of FDI on the energy transition. We found that FDI and SO2 emissions are characterized by an inverted U-shaped relationship; FDI and coal consumption have an inverted U-shaped relationship, and FDI and natural gas consumption have a U-shaped relationship. Moreover, the use of coal significantly increases SO2 emissions while the use of natural gas significantly reduces them. Our research shows that technological advances have increased coal consumption and that there has been no reduction of SO2 emissions in China. Overall, our analysis provides mixed support for the pollution haven and pollution halo hypotheses.

Cleaner production vs end-of-pipe treatment: Evidence from industrial SO2 emissions abatement in China

Understanding the roles and regional differences associated with cleaner production (CP) and end-of-pipe treatment (ET) can provide valuable information for the reduction of pollutant emissions. Considering the differences of these impact pathways, this paper proposes a two-stage decomposition method for investigating the contributions of CP and ET to the reduction of pollutant emissions. This two-stage method enhances the accuracy and obtainable detail of the decomposition results. Then, empirical research was conducted by decomposing the changes of China's industrial sulfur dioxide (SO2) emissions during 2005–2015. At the national level, CP and ET both decreased Chinese SO2 emissions, and CP has become the dominant approach for SO2 emission reduction in 2010–2015. Moreover, coal pollution intensity and treatment strength are key factors that need to be improved in CP and ET, respectively. At the provincial level, CP exerts a stronger impact on SO2 emission differences among different regions, while ET exerts less impact on SO2 emission differences among different regions. Based on the decomposition results, this paper presents targeted policy implications.

Catalytic combustion of sulfur-containing liquid fuels in the fluidized bed: Experiment and modeling

Environmentally safe fuel combustion is an actual worldwide problem. The alternative technology of combustion in fluidized bed of catalyst was developed in the Boreskov Institute of Catalysis. The technology allows one to conduct the process at 400–700 оC and significantly reduce outlet concentrations of toxic compounds. However, the use of sulfur oils as fuel demands solving a problem of the decreasing the outlet SO2 concentration because the oils contain small amount of ash to absorb SO2. The work is devoted to study features of sulfur light oil and high-sulfur heavy oil combustion in the fluidized bed of the Al–Cu–Cr-oxide catalyst. Reduction of SO2 emission at conserving oxidation degree of oils within range of 99.5–99.8% might be reached by using a non-isothermal temperature profile in the reactor as well as a use of CaCO3 or CaO at Ca/S > 2 to absorb sulfur oxides. The non-isothermal temperature profile in the reactor consisted of an oxidation zone with the temperature in the fluidized bed of 700 оC and a catalytic oxidation of SO2 to SO3 zone with equilibrium shift to reducing SO2 concentration because of the temperature change from 700 оC to 585 оC.

Temporal trends of sulfur levels in soils of northwestOhio(USA) between 2002 and 2014

AbstractSulfur (S) is an essential nutrient for plant growth. Despite increasing reports of yield responses of crops to S fertilization, there is limited information about changes in the soil test concentrations of S. This study used a soil chemical analysis dataset from 2002 to 2014 to evaluate changes in soil S and other nutrient levels. The soil‐test database comprised 8,428 topsoil samples (0–20 cm depth layer) collected from 143 farm fields located in the northwest (NW) Ohio counties of Defiance, Paulding, and Williams. Except for S, the database showed no significant changes in soil chemical properties from NW Ohio between 2002 and 2014. Soil sulfate (SO42−) levels have linearly decreased by 63% from 2002 to 2014, reaching the range of concentration considered deficient for the main cereal crops. With no changes in soil organic matter (SOM) and pH, this result was attributed primarily to enactment of air quality regulations, since soil SO42−decreases were directly correlated with the reductions of SO2emissions (−70%), SO42−in rainwater (−66%) and deposited (−52%) in NW Ohio between the years of 2002–2013. Furthermore, combined increasing crop yields and insufficient compensation by fertilization had role on decreasing soil SO42−levels. Current fertilization practices and wet deposition of S have not been sufficient to balance S removals from soil leading to the declines in the soil test S levels. It is imperative to paid more attention to practices that maintain soil S fertility levels to avoid yield penalties associated with soil S deficiencies.

Modeling the spatiotemporal dynamics of industrial sulfur dioxide emissions in China based on DMSP-OLS nighttime stable light data.

Due to the rapid economic growth and the heavy reliance on fossil fuels, China has become one of the countries with the highest sulfur dioxide (SO2) emissions, which pose a severe challenge to human health and the sustainable development of social economy. In order to cope with the serious problem of SO2 pollution, this study attempts to explore the spatial temporal variations of industrial SO2 emissions in China utilizing the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP-OLS) nighttime stable light (NSL) data. We first explored the relationship between the NSL data and the statistical industrial SO2 emissions at the provincial level, and confirmed that there was a positive correlation between these two datasets. Consequently, 17 linear regression models were established based on the NSL data and the provincial statistical emissions to model the spatial-temporal dynamics of China’s industrial SO2 emissions from 1997 to 2013. Next, the NSL-based estimated results were evaluated utilizing the prefectural statistical industrial SO2 emissions and emission inventory data, respectively. Finally, the distribution of China’s industrial SO2 emissions at 1 km spatial resolution were estimated, and the temporal and spatial dynamics were explored from multiple scales (national scale, regional scale and scale of urban agglomeration). The results show that: (1) The NSL data can be successfully applied to estimate the dynamic changes of China’s industrial SO2 emissions. The coefficient of determination (R2) values of the NSL-based estimation results in most years were greater than 0.6, and the relative error (RE) values were less than 10%, when validated by the prefectural statistical SO2 emissions. Moreover, compared with the inventory emissions, the adjusted coefficient of determination (Adj.R-Square) reached 0.61, with the significance at the 0.001 level. (2) During the observation period, the temporal and spatial dynamics of industrial SO2 emissions varied greatly in different regions. The high growth type was largely distributed in China’s Western region, Central region, and Shandong Peninsula, while the no-obvious-growth type was concentrated in Western region, Beijing-Tianjin-Tangshan and Middle south of Liaoning. The high grade of industrial SO2 emissions was mostly concentrated in China’s Eastern region, Western region, Shanghai-Nanjing-Hangzhou and Shandong Peninsula, while the low grade mainly concentrated in China’s Western region, Middle south of Liaoning and Beijing-Tianjin-Tangshan. These results of our research can not only enhance the understanding of the spatial-temporal dynamics of industrial SO2 emissions in China, but also offer some scientific references for formulating feasible industrial SO2 emission reduction policies.

Reduction of atmospheric emissions due to switching from fuel oil to natural gas at a power plant in a critical area in Central Mexico

ABSTRACT A case study was conducted to evaluate the SO2 emission reduction in a power plant in Central Mexico, as a result of the shifting of fuel oil to natural gas. Emissions of criteria pollutants, greenhouse gases, organic and inorganic toxics were estimated based on a 2010 report of hourly fuel oil consumption at the “Francisco Pérez Ríos” power plant in Tula, Mexico. For SO2, the dispersion of these emissions was assessed with the CALPUFF dispersion model. Emissions reductions of > 99% for SO2, PM and Pb, as well as reductions >50% for organic and inorganic toxics were observed when simulating the use of natural gas. Maximum annual (993 µg/m3) and monthly average SO2 concentrations were simulated during the cold-dry period (152–1063 µg/m3), and warm-dry period (239–432 µg/m3). Dispersion model results and those from Mexico City’s air quality forecasting system showed that SO2 emissions from the power plant affect the north of Mexico City in the cold-dry period. The evaluation of model estimates with 24 hr SO2 measured concentrations at Tepeji del Rio suggests that the combination of observations and dispersion models are useful in assessing the reduction of SO2 emissions due to shifting in fuels. Being SO2 a major precursor of acid rain, high transported sulfate concentrations are of concern and low pH values have been reported in the south of Mexico City, indicating that secondary SO2 products emitted in the power plant can be transported to Mexico City under specific atmospheric conditions. Implications: Although the surroundings of a power plant located north of Mexico City receives most of the direct SO2 impact from fuel oil emissions, the plume is dispersed and advected to the Mexico City metropolitan area, where its secondary products may cause acid rain. The use of cleaner fuels may assure significant SO2 reductions in the plant emissions and consequent acid rain presence in nearby populated cities and should be compulsory in critical areas to comply with annual emission limits and health standards.

Spatial-Temporal Analysis and Driving Factors Decomposition of (De)Coupling Condition of SO2 Emissions in China.

China has a fast-growing economy and is one of the top three sulfur dioxide (SO2) emitters in the world. This paper is committed to finding efficient ways for China to reduce SO2 emissions with little impact on its socio-economic development. Data of 30 provinces in China from 2000 to 2017 were collected to assess the decoupling relationship between economic growth and SO2 emissions. The Tapio method was used. Then, the temporal trend of decoupling was analyzed and the Moran Index was introduced to test spatial autocorrelation of the provinces. To concentrate resources and improve the reduction efficiency, a generalized logarithmic mean Divisia index improved by the Cobb–Douglas function was applied to decompose drivers of SO2 emissions and to identify the main drivers. Results showed that the overall relationship between SO2 emissions and economic growth had strong decoupling (SD) since 2012; provinces, except for Liaoning and Guizhou, have reached SD since 2015. The decoupling indexes of neighboring provinces had spatial dependence at more than 95% certainty. The main positive driver was the proportion of the secondary sector of the economy and the main negative drivers were related to energy consumption and investment in waste gas treatment. Then, corresponding suggestions for government and enterprises were made.

The Impact of Foreign SO2 Emissions on Aerosol Direct Radiative Effects in South Korea

This study examined the impact of foreign SO2 emission changes on the aerosol direct radiative effects (ADRE) in South Korea. Simulations that applied basic emissions (BASE) and simulations that applied reduced SO2 emissions from foreign sources (R_FSO2) were performed, respectively, using the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) two-way coupled model. In addition, the difference between the two experimental results was calculated (i.e., R_FSO2 minus BASE) to quantitatively identify the impact of foreign SO2 emission reduction. The reduction in foreign SO2 emissions caused a decrease in the concentration of SO2 flowing in from overseas to South Korea. As a result, a clear decrease in SO42− concentration was shown mainly in the southwest coast of South Korea. The difference in PM2.5 concentration in South Korea according to the foreign SO2 emission reduction did not correspond to the difference in SO42− concentration; it was determined in a complex way by the changes in SO42− concentration caused by SO2 concentration changes, and the subsequent series of changes in NO3− and NH4+ concentrations. The differences in SO42− and PM2.5 concentrations caused by the foreign SO2 reduction also affected the ADRE changes in South Korea. The distribution of ADRE difference between the two experiments was not consistent with the distribution of PM2.5 concentration difference, but it was very similar to the distribution of SO42− concentration difference. These results imply that the ADRE of South Korea is not simply proportional to PM2.5 concentration and may be determined by concentration changes of SO42−.

The inharmonious mechanism of CO2, NOx, SO2, and PM2.5 electric vehicle emission reductions in Northern China

Beijing benefits from the promotion of electric vehicles (EVs) in the improvement of road tailpipe emissions; these emissions are caused by internal combustion engine vehicles (ICEVs) and reduce the surrounding environmental quality. When analyzing the electricity grid, upstream emissions of EVs in Beijing can be tracked back to Shanxi and Inner Mongolia. This study investigates the inharmonious mechanism of emission reduction to promote EVs in Beijing and Northern China based on 6 scenarios and 42 real EVs. Because there is a neighbor effect, Beijing only accounts for 34%, 34%, 41%, and 35% of the total CO2, NOx, SO2 and PM2.5 emissions, respectively. Although the local CO2, NOx, and PM2.5 emissions can be easily reduced (as long as the conversion of “coal to gas” plan is realized), it is difficult to achieve emission reductions of NOx and SO2 without increasing the clean electricity generation mix in Shanxi and Inner Mongolia at the total emission level. However, there is still a large reduction potential of EVs themselves due to an increasingly clean electricity mix in Beijing, Shanxi and Inner Mongolia. Beijing local CO2, NOx, SO2 and PM2.5 emissions can be reduced by 86.92%, 98.79%, 99.98% and 99.94%, respectively, and a total reduction of 78.43% of CO2, 93.83% of NOx, 97.85% of SO2 and 99.26% of PM2.5 emissions is possible. Compared with the corresponding ICEV, an EV of 18 kWh/100 km starts to reduce Beijing local CO2, NOx and PM2.5 emissions in scenario 1, 3 and 1, respectively, while the SO2 emissions cannot be reduced. However, the total CO2, NOx, SO2 and PM2.5 emissions can be reduced in scenario 2, 5, 5, and 1, respectively. A sensitivity analysis shows that the promotion of EVs can reduce Beijing local CO2, NOx, SO2 and PM2.5 emissions by 125.568–238.960 g/km, 0.059–0.113 g/km, −0.00003 - - 0.00007 g/km and 0.034–0.065 g/km, respectively. In addition, the total CO2, NOx, SO2 and PM2.5 reduction in emissions can be 132.883–253.757 g/km, 0.189–0.361 g/km, 0.299–0.569 g/km and 0.053–0.101 g/km, respectively.

Taguchi Approach and ANOVA in Optimization of the Dissolution of Colemanite in CO2 and SO2- Water Systems

Background:Turkey is approximately 72% of the world’s boron sources. Colemanite, tincal, ulexite and pandermite are among the most significant in Turkey. Boron compounds and minerals are widely used in many industrial fields.Objective:The main purpose of this study was to investigate the control of impurities in the boric acid production process using colemanite by carrying out the reaction with a mixture of CO2 and SO2 - water, and determining the appropriate process conditions to develop a new process as an alternative to the use of sulfuric acid. Due to worrying environmental problems, intensive studies are being carried out globally to reduce the amount of CO2 and SO2 gases released to the atmosphere.Methods:The Taguchi method is an experimental design method that minimizes the product and process variability by selecting the most appropriate combination of the levels of controllable factors compared to uncontrollable factors.Results:It was evaluated the effects of parameters such as reaction temperature, solid-to liquid ratio, SO2/CO2 gas flow rate, particle size, stirring speed and reaction time. The optimum conditions determined to be reaction temperature of 45°C; a solid–liquid ratio of 0.083 g.mL−1; an SO2/CO2 ratio of 2/2 mL.s−1; a particle size of -0.354+0 .210 mm; a mixing speed of 750 rpm and a reaction time of 20 min.Conclusion:Under optimum operating conditions, 96.8% of colemanite was dissolved. It is thought that the industrial application of this study will have positive effects on the greenhouse effect by contributing to the reduction of CO2 and SO2 emissions that cause global warming.