Reduction Of Sulfur Emissions Research Articles

Exploring the Mechanisms of Regional Environmental Collaborative Legislation in China: Policy Effectiveness, Practical Challenges, and Policy Suggestions

The legislation for regional environmental collaboration is of significant importance in enhancing the effectiveness of environmental protection. The existing literature focuses on the power struggle between central and local governments regarding environmental regulation within the realm of regional environmental governance, lacking an examination of the collaborative governance mechanisms and their effectiveness. Therefore, this study takes China’s regional environmental collaborative legislation as its research object. It employs a difference-in-differences model to test the effectiveness of regional environmental collaborative legislation concerning environmental governance and conducts a qualitative analysis to examine the current practical challenges facing regional environmental collaborative legislation. The quantitative analysis results indicate that regional environmental collaborative legislation can effectively suppress the emission of environmental pollutants. Specifically, the implementation of regional environmental collaborative legislation results in a 19.7% reduction in prefecture-level wastewater emissions and a 26.6% reduction in sulfur dioxide emissions. Qualitative analysis results show that regional environmental collaborative legislation currently faces challenges such as localism, difficulties in legislative authority allocation, and a lack of cooperation mechanisms. Therefore, this paper proposes to establish a collaboration platform, balance the interests of stakeholders, and improve the allocation mechanism of environmental regulatory powers in order to better optimize the regional environmental collaborative legislation and enhance the government’s environmental governance capacity.

Scrubber installation of inland container ships: Discrepancy between government and carriers

Scrubbers are the commonly used green technologies for a ship to reduce sulfur emissions. Various speed adjustment behaviors would distort the cost and desulfurization efficiency of scrubbers for ships, which causes a discrepancy between the government and the carrier to install scrubbers. This paper addresses the issue by considering three speed adjustment behaviors: rigidity, partial flexibility, and full flexibility. Under rigid behavior, the carrier maintains a constant sailing speed when adopting low-sulfur fuel oil (LSFO) and installing a scrubber. Partially flexible behavior only involves speed adjustments when adopting LSFO, while fully flexible behavior includes speed adjustments when adopting LSFO and installing a scrubber. Our analysis indicates that scrubber installation consistently precedes adopting LSFO in speed. Full flexibility behavior is the least costly speed adjustment behavior, while partial flexibility behavior results in the lowest emissions. The investment discrepancy on scrubbers between the carrier and the government would occur on whether or not to install a scrubber and which level of the scrubber’s quality since the two parties are concerned about the sulfur emissions and cost, respectively. Government subsidies address these discrepancies, leading to improved emission reduction.

Does ecological economic zone policy affect pollutant emission: Evidence from a case study of Dongting Lake

Environmental pollution affects human health, reduces work motivation, and addressing environmental pollution is a common challenge faced by the world. The Chinese government has recently implemented a new environmental policy - the national-level ecological economic zone - to develop a green economy and reduce environmental pollution. This study utilizes the difference-in-difference method to analyze the impact of the Dongting Lake ecological economic zone on environmental pollution. The results show that: policy led to a 68 % reduction in sulfur dioxide emissions. This impact was more pronounced in economically developed areas, regions with a high concentration of foreign-invested, and areas with greater economic openness. Mechanism tests indicate that the policy reduces environmental pollution by promoting technological progress. Robustness checks show that the policy also resulted in a 37 % reduction in industrial wastewater emissions. The results offer new insights to advance the development of the ecological economic zone more effectively. The ecological economic zone should focus on enhancing technological advancement and green total factor productivity to amplify the policy's positive effects.

Optimizing Sulfur Emission Control Areas for Shipping

The design of emission control areas (ECAs), including ECA width and sulfur limits, plays a central role in reducing sulfur emissions from shipping. To promote sustainable shipping, we investigate an ECA design problem that considers the response of liner shipping companies to ECA designs. We propose a mathematical programming model from the regulator’s perspective to optimize the ECA width and sulfur limit, with the aim of minimizing the total sulfur emissions. Embedded within this regulator’s model, we develop an internal model from the shipping liner’s perspective to determine the detoured voyage, sailing speed, and cargo transport volume with the aim of maximizing the liner’s profit. Then, we develop a tailored hybrid algorithm to solve the proposed models based on the variable neighborhood search meta-heuristic and a proposition. We validate the effectiveness of the proposed methodology through extensive numerical experiments and conduct sensitivity analyses to investigate the effect of important ECA design parameters on the final performance. The proposed methodology is then extended to incorporate heterogeneous settings for sulfur limits, which can help regulators to improve ECA design in the future. Funding: This work was supported by the National Natural Science Foundation of China [Grants 72025103, 71831008, 72201163, 72071173, 72371221, 72394360, 72394362, 72361137001 and HKSAR RGC TRS T32-707/22-N]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2023.0278 .

REACTOR SECTION PRESSURE CONTROL AT DIESEL HYDROTREATING UNIT

Diesel Hydrotreating Units (DHUs) are essential components within petroleum refineries, playing a critical role in the production of clean and high-quality diesel fuel. This abstract provides a comprehensive overview of the mechanisms, necessity, and operational significance of DHUs in the refining process. Firstly, the abstract discusses the fundamental principles underlying the operation of DHUs. The catalytic hydrotreating process is elucidated, highlighting the role of hydrogenation reactions in the removal of sulfur, nitrogen, and aromatic compounds from diesel feedstocks. The synergy between catalysts and hydrogen gas in promoting desulfurization, denitrification, and hydrodenitrogenation reactions is examined, emphasizing the pivotal role of DHUs in enhancing the environmental and performance attributes of diesel fuel. Furthermore, the abstract addresses the imperative need for Diesel Hydrotreating Units. The detrimental impacts of sulfur-containing compounds, such as sulfur oxides (SOx), on air quality and human health are discussed, underscoring the regulatory mandates aimed at reducing sulfur emissions from diesel fuel. DHUs emerge as indispensable tools for compliance with stringent environmental regulations, ensuring the production of low-sulfur diesel fuel that meets or exceeds regulatory standards. Moreover, the abstract emphasizes the operational significance of DHUs within petroleum refineries. Through the integration of advanced reactor designs, catalyst technologies, and process optimization strategies, DHUs enable refineries to achieve efficient desulfurization and meet production targets while minimizing energy consumption and operational costs. The adaptability of DHUs to varying feedstock compositions and processing conditions further underscores their versatility and importance in the refining industry. In conclusion, this abstract provides a comprehensive overview of Diesel Hydrotreating Units, elucidating their mechanisms, necessity, and operational significance in the production of clean and high-quality diesel fuel. By facilitating the removal of sulfur and other impurities from diesel feedstocks. Keywords: Diesel Hydrotreatment Unit, Control Systems, Petrochemical Industry, Efficiency, Safety.

Impact of Biomass Fuel Feeding Ratio in Co-firing Circulating Fluidized Bed Boiler: A Computational Fluid Dynamics Study

Nowadays, our global population is on a notable rise, coupled with an annual surge in energy consumption. The prevailing reliance on fossil fuels, especially in electricity generation, has significantly contributed to environmental pollution and exacerbated global warming. The circulating fluidized bed, distinguished for its continuous operation and effective heat transfer in the combustion chamber, emerges as a prominent boiler type. Furthermore, the use of biomass fuel, recognized for its renewable and environmentally friendly characteristics, presents an attractive option. Hence, exploring a co-firing system incorporating both coal and biomass as fuel feeds for the boiler holds promise, necessitating optimization for efficient energy production and reduced gas emissions. This study employs computational fluid dynamics to simulate the intricate interactions of solid fuel and flue gas reactions within the boiler, utilizing the two-fluid method for multiphase flow simulation. The circulating fluidized bed boiler in focus employs subbituminous coal, woodchips as biomass sources, and sand as the bed material. Model validation against operational data, including bed temperature, flue gas velocity outlet, and carbon dioxide mass fraction, indicates minimal deviation. Examination of the biomass ratio's impact on fuel feed reveals a reduction in sulfur dioxide emissions with an increasing biomass ratio, attributed to the lower sulfur content in woodchips compared to coal. However, a heightened woodchip blending ratio results in diminished boiler efficiency due to the altered heating value of the mixed solid fuel. The optimized biomass-to-coal ratio in fuel feeding is determined as 59.15%, achieving a maximized boiler efficiency of 82.84% and minimized pollution gas emissions of sulfur oxide and nitrogen oxide in accordance with industrial standards.

Torrefaction of Willow in Batch Reactor and Co-Firing of Torrefied Willow with Coal

The torrefaction process represents a thermal conversion technique conducted at relatively low temperatures ranging between 200 to 300 °C. Its objective is to produce fuel with a higher energy density by decomposing the reactive portion of hemicellulose. In this study, the kinetics of mass loss during torrefaction were investigated for willow. The experiments were carried out under isothermal conditions using thermogravimetric analysis. Batch torrefaction reactor designs were conducted and explained in detail. Co-combustion of willow with hard coal (origin: Katowice mine) in different mass ratios (25% biomass + 75% coal, 50% biomass + 50% coal, and 75% biomass + 25% coal) was conducted in addition to raw biomass torrefaction. TG/MS analysis (a combination of thermogravimetric analysis with mass spectrometry analysis) was performed in the research. The optimal torrefaction conditions for willow were identified as an average temperature of 245 °C and a residence time of 14 min, resulting in the lowest mass loss (30.15%). However, it was noted that the composition of torgas, a by-product of torrefaction, presents challenges in providing a combustible gas with sufficient heat flux to meet the energy needs of the process. Prolonged residence times over 15 min and higher average temperatures above 250 °C lead to excessive energy losses from volatile torrefaction products, making them suboptimal for willow. On the other hand, the co-combustion of torrefied biomass with hard coal offers advantages in reduced sulfur emissions but can lead to increased NOx emissions when biomass with a higher nitrogen content is co-combusted in proportions exceeding 50% biomass. This paper summarizes findings related to optimizing torrefaction conditions, challenges in torgas composition, and the emissions implications of co-combustion.

A coordinated generation and voyage planning optimization scheme for all-electric ships under emission policy

The International Maritime Organization has introduced the concept of Emission Control Area to reduce sulfur emissions from coastal areas. The expensive low-sulfur fuels are required to be used in Emission Control Area, leading to increased sulfide emissions due to bypassing by ship operators. It creates new challenges for navigation and power generation scheduling of all-electric ships. This article presents a new bi-objective joint optimization scheme for ship sailing routes and energy management. It considers emission control strategies to balance the total cost of operation and sulfur dioxide emissions throughout the ship’s voyage. Unlike previous optimization problems with fixed routes and sailing time, the influence of emission policies on the operator’s navigation decisions is considered. The route options and sailing time are treated as variables embedded in the model. In addition, the optimization accuracy is improved by integrating the model into mixed integer linear programming through a modified piecewise linearization model. The results show that the total operating cost for the same route is reduced by 6.05%, and the SO2 emission is 8.36% after integrating the emission policy influencing factor in the model. The effectiveness of the proposed scheme is validated, and the model’s necessity for optimizing ship power generation and voyage within Emission Control Area is also illustrated.

Optimal Shipping Route under the Designation of the Mediterranean Sulfur Emission Control Area: Mathematical Models and Applications

In order to tackle sulfur oxides (SOx) emissions from maritime activities, both local governmental bodies and the International Maritime Organization (IMO) have implemented a range of regulations with the establishment of sulfur emission control areas (SECAs) being one crucial measure. Recently, the IMO made the significant decision to designate the Mediterranean as an SECA, aiming to promote environmental conservation as well as sustainable development in the maritime industry and mitigate the adverse health effects caused by air pollutants emitted from ships in Mediterranean regions. While this policy signifies significant progress in the reduction of sulfur emissions, it simultaneously presents intricate challenges for maritime enterprises. Notably, under the Mediterranean SECA designation, shipping companies may opt to bypass this region and choose routes through the Cape of Good Hope as a means of minimizing the overall costs, resulting in a potential increase in global carbon emissions. To support shipping companies in formulating optimal strategies within the framework of this new policy, the research introduces advanced techniques to make the optimal decisions concerning route selection, sailing speeds, and the appropriate number of ships for both SECAs and non-SECAs. Furthermore, we elucidate how these optimal decisions can be dynamically adapted in response to the dynamic fluctuations in fuel prices and the weekly operational expenditures incurred by maritime fleets. In the experimental results, taking into account factors like route distance and fuel costs, shipping companies select routes through the Mediterranean region in both eastward and westward directions. The total cost amounts to $6,558,766.78, utilizing eight vessels. Regarding ship speeds, vessels sail at reduced speeds in SECAs compared to non-SECAs. Furthermore, longer voyage distances require deploying a greater number of ships to maintain a weekly service frequency. This research exhibits robust timeliness and practicality, which is in line with practice. It not only timely supplements and enhances the extant body of knowledge concerning SECAs but also serves as a valuable point of reference and emulation for shipping companies seeking to optimize their operations within the framework of the new policy landscape. Furthermore, it offers pertinent insights for the IMO in formulating policies related to SECAs.

Has China achieved synergistic reduction of carbon emissions and air pollution? Evidence from 283 Chinese cities

Confronted with the dual pressures of carbon emissions and air pollution, examining their synergistic effects becomes increasingly paramount in China. This study verifies and quantifies the bidirectional synergistic effects between reductions in carbon emissions and air pollutants (SO2 and PM2.5) at the city level. We also analyzed the spatial spillover of this effect among cities, investigating the dynamic evolution, heterogeneity, and underlying mechanisms of both synergistic reduction and increase effects across different time scales. Key findings include: 1) Carbon emission mitigation causes greater synergistic reduction effect than pollution reduction; 2) Carbon emission reduction has a more significant synergistic effect on SO2 than PM2.5; 3) Synergistic effects vary across city types. Cities with higher resource endowments, lower administrative levels, smaller populations, and lower economic status show greater synergistic effects; 4) The synergistic effects demonstrate significant positive spatial spillovers across cities, with local reductions in carbon and sulfur emissions spurring sulfur emission reductions in neighboring regions; 5) Synergistic reduction effects between carbon and air pollutant emissions exhibit temporal delays, while their synergistic increase effects are pronounced in both short and long terms; 6) R&D investment mitigates synergistic increase effects, while the impact of energy efficiency on synergistic reduction effects shows an inverted U-curve relationship. Our findings offer valuable insights for policymakers seeking to simultaneously tackle climate change and environmental pollution more effectively.

Clean Preparation of Formed Coke from Semi-coke by the Carbonated Consolidation Process.

In order to address the low thermal efficiency of low-rank coal combustion and the accompanying serious environmental issues, formed coke was prepared using a carbonization consolidation method with low-rank coal semi-coke. The test for briquetting and carbonation consolidation conditions revealed that the optimal parameters were a briquetting pressure of 93.63 MPa, moisture content of 16%, Ca(OH)2 binder amount of 10%, and a CO2 concentration of 30% at 20 °C. Under these conditions and a carbonation consolidation time of 60 min, high-quality formed coke was produced, exhibiting a compressive strength of 1256.2 N/a, redrying strength of 286.2 N/a, and a dropping strength of 10.6 number/a. The combustion characteristics of the prepared formed coke were investigated, revealing that ignition temperatures (345.39 °C), burnout temperatures (495.57 °C), and peak of the maximum weight loss rate temperatures (437.93 °C) are slightly higher than those of bituminous coal. The low calorific value of the briquette was 20.4 MJ/kg. During the combustion process, the emission concentrations of SO2, NOX, and solid particles from the formed coke were significantly lower than those of bituminous coal, indicating that it is a cleaner energy source. Moreover, adding Ca(OH)2 effectively reduced SO2 emissions and achieved sulfur fixation and emission reduction.

Toxic effects of ship exhaust gas closed-loop scrubber wash water.

To meet the strict requirements of reducing sulfur emissions, an increasing number of commercial ships have installed exhaust gas cleaning systems (EGCSs). However, wash water produced during the cleaning process is discharged back to the marine environment. We investigated the effects of closed-loop scrubber (natrium-alkali method) wash water on three trophic species. Severe toxic effects were found when Dunaliella salina, Mysidopsis bahia, and Mugilogobius chulae were exposed to 0.63-6.25, 0.63-10, and 1.25-20% concentrations of wash water, respectively. The 50% effective concentration in 96h (EC50-96h) for D. salina was 2.48%, and the corresponding total polycyclic aromatic hydrocarbons (PAHs) and heavy metals were 22.81 and 23.67μg L-1. The 50% lethal concentration in 7d (LC50-7d) values for M. bahia and M. chulae were 3.57% and 20.50%, respectively. The lowest observed effect concentration (LOEC) values for M. bahia and M. chulae were 1.25% and 2.5%, respectively, and the corresponding total PAHs and heavy metals were 11.50 and 11.93 and 22.99 and 23.86μg L-1. M. bahia's body weight was negatively correlated with the amount of wash water. Low concentrations of wash water (0-5%) had no significant effect on the reproduction of M. bahia. Although concentrations of 16 PAHs and 8 heavy metals are known, different compounds might react with each other and form more unknown toxic substances, and the measured toxicity comes from synergistic effects between various pollutants. Therefore, future work is needed to clarify other more toxic contaminants in wash water. We highly recommend that wash water be treated before being discharged to the marine environment.

Using a multi-proxy paleolimnological approach to track the effects of multiple stressors on a naturally acidic lake from Killarney Provincial Park (Ontario, Canada)

Ruth-Roy Lake (Killarney Provincial Park, Ontario, Canada) is an ultra-oligotrophic, naturally acidic waterbody. Lakes in Killarney Provincial Park were impacted by long-range transportation of contaminants from copper-nickel smelting operations in nearby Sudbury, but recent lake monitoring indicates that Ruth-Roy Lake has been less acidic than inferred pre-industrial pH conditions. We assessed the effects of pH change, reduced sulphur emissions, and drivers of reduced acidity using biological and geochemical paleolimnological techniques. Ruth-Roy Lake experienced notable biological and chemical change over the past ~150 years. All examined proxies supported that Ruth-Roy Lake was naturally acidic but further acidified as early as ca. 1920s, with the strongest acidification signal apparent in ca. 1940s. Biological recovery in diatom and cladoceran assemblages, however, is modest. We highlight the importance of understanding reference conditions to assess ecosystem recovery and climate-mediated change in clear acidic lakes located in industrial landscapes.

Emission characteristics of particulate matter emitted from 4- and 2-stroke marine diesel engines under the background of sulfur emission reduction.

With the implementation of sulfur emission regulations, influences of particulate matter (PM) emitted by marine diesel engines on nearshore atmospheric environment and human health are of increasingly concern. Whatever measures are chosen to meet sulfur emission regulations, the emission characteristic and influencing factors of PM should also be determined. In this study, number and mass emissions, volatility, main composition, and toxicity of PM from marine 4- and 2-stroke diesel engines were investigated. It was found that the size distribution curves of particle number are multiple peaks. Fuels and engines types influence the modal distribution of particles number concentration. For light diesel oil and low-sulfur heavy fuel oil (HFO), particle number was dominated by nucleation and accumulation mode respectively, and particle mass was dominated by accumulation mode. Reduction of fuel sulfur content (FSC) could reduce the particles mass, number and fraction of volatile substance emissions, and small-size particles had the most volatility. Particulate organic carbon (OC) was the main substance, especially for marine 2-stroke diesel engine burning HFO (high- or low-sulfur), while particulate OC contained a large number of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes. The PAHs also had very high toxicity when the engine was burning HFO. The use of low-sulfur HFO cannot make the marine diesel engine meet the current and upcoming PM regulations, and after-treatment technologies or cleaning fuel should be needed.

Fifty years of reduction in sulphur deposition drives recovery in soil pH and plant communities

Abstract Sulphur deposition through rainfall has led to species loss and ecosystem degradation globally, and across Europe huge reductions in sulphur emissions since the 1970s were expected to promote the recovery of acidified ecosystems. However, the rate and ecological impact of recovery from acidification in terrestrial ecosystems is still unclear as is the influence of management and climate, as to date there has been no long‐term spatially extensive evaluation of these changes. Here, we present data from thousands of sites across Great Britain (pH range 3.3–8.7) surveyed repeatedly from 1978–2019 and assess change in soil pH and plant acidity preference (Ellenberg R) in response to atmospheric deposition of sulphur and nitrogen. We analyse change in grasslands managed for pasture, referred to as high‐intensity habitats, and compare to seminatural habitats comprising rough grassland, broadleaved woodland, bog and heathland, referred to as low‐intensity habitats. Soil pH increased from 1978 to 2007 but then decreased between 2007 and 2019, resulting in a net increase of ~0.2 pH units in low‐intensity habitats but no change in high‐intensity habitats. The community average Ellenberg R increased in seminatural habitats by ~0.2 units but remained stable in intensive grasslands. In seminatural habitats, but not intensive grasslands, these changes in plant community composition were associated with the soil pH changes which were in turn linked to decreasing sulphur deposition and differences in rainfall. Nitrogen deposition, which was relatively stable over the survey period, showed no additional effect upon soil acidity once sulphur deposition was accounted for. Synthesis: Our results provide conclusive evidence that reductions in acid emissions are stimulating the gradual recovery of chronically acidified terrestrial ecosystems at a whole‐country scale, while also suggesting this recovery is being compromised by changing climate and land management.

Clean air policies are key for successfully mitigating Arctic warming

A tighter integration of modeling frameworks for climate and air quality is urgently needed to assess the impacts of clean air policies on future Arctic and global climate. We combined a new model emulator and comprehensive emissions scenarios for air pollutants and greenhouse gases to assess climate and human health co-benefits of emissions reductions. Fossil fuel use is projected to rapidly decline in an increasingly sustainable world, resulting in far-reaching air quality benefits. Despite human health benefits, reductions in sulfur emissions in a more sustainable world could enhance Arctic warming by 0.8 °C in 2050 relative to the 1995–2014, thereby offsetting climate benefits of greenhouse gas reductions. Targeted and technically feasible emissions reduction opportunities exist for achieving simultaneous climate and human health co-benefits. It would be particularly beneficial to unlock a newly identified mitigation potential for carbon particulate matter, yielding Arctic climate benefits equivalent to those from carbon dioxide reductions by 2050.

‘Best-scenic zone’ selection as a method of reducing sulfur dioxide emissions: A quasi-experiment in Chinese urban environmental governance

By treating the designation of “best-scenic zone” as an exogenous event for a natural experiment, we apply a difference-in-difference method to gauge the extent to which the designation of best-scenic zone can help alleviate the conflict caused by environmental protection and economic growth for local governments, increase the attention to environmental governance, and therefore reduce the emission of sulfur dioxide. Our results indicate a significant reduction of sulfur dioxide emissions in cities designated as best-scenic zone, especially in ones facing high public pressure. Our study enriches studies on environmental governance by guiding local governments on how to strike a balance between economic growth and environmental governance.

Particle characterization and quantification of organic and inorganic compounds from Chinese and Iranian aerosol filter samples using scanning laser desorption/ionization mass spectrometry

Besides their influence on climate and cloud formation, many organic and inorganic substances in aerosol particles pose a risk to human health. Namely, polycyclic aromatic hydrocarbons (PAH) and heavy metals are suspected to be carcinogenic or acutely toxic. The detection and quantification of such compounds is difficult if only small amounts of particulate matter (PM) are available. In addition, filter samples are often complex and time-consuming to prepare for chromatographic measurements and elemental analysis. Here, we present a method based on high-resolution atmospheric pressure laser desorption ionization mass spectrometry imaging (AP-LDI-MSI) and statistical analysis which allows the analysis and characterization of very small sample quantities (< 30 µg) without any sample preparation. The power and simplicity of the method is demonstrated by two filter samples from heavily polluted mega cities. The samples were collected in Tehran (Iran) and Hangzhou (China) in February 2018. In the course of the measurement, more than 3200 sum formulae were assigned, which allowed a statistical evaluation of colocalized substances within the particles on the filter samples. This resulted in a classification of the different particle types on the filters. Finally, both megacities could be distinguished based on characteristic compounds. In the samples from Tehran, the number of sulphur-containing organic compounds was up to 6 times as high as the samples from Hangzhou, possibly due to the increasing efforts of the Chinese government to reduce sulphur emissions in recent years. Additionally, quantification of 13 PAH species was carried out via standard addition. Especially, the samples from Tehran showed elevated concentrations of PAHs, which in the case of higher-molecular-weight species (> m/z 228) were mostly more than twice as high as in Hangzhou. Both cities showed high levels of heavy metals and potentially harmful organic compounds, although their share of total particulate matter was significantly higher in the samples from Tehran. The pre-treatment of the samples was reduced to a minimum with this method, and only small amounts of particles were required to obtain a comprehensive picture for a specific filter sample. The described method provides faster and better control of air pollution in heavily polluted megacities.Graphical abstract

Environmental regulation, human capital, and pollutant emissions: the case of SO2 emissions for China

ABSTRACT This study aims to explore whether the impact of environmental regulation on pollution emissions varies across China’s regions under different human capital levels. And whether environmental regulation will affect sulfur emissions through human capital is also examined. The empirical results conclude that: (1) environmental protection investment cannot effectively contribute to sulfur emission reduction for the full sample; (2) environmental regulation can aggravate pollution emissions when human capital is low, while human capital is in a high-level, enhanced regulation can help reduce pollution emissions; and (3) environmental regulation can help strengthen sulfur reduction through human capital accumulation; however, the reduction of sulfur emissions by human capital cannot offset the direct positive effect of environmental regulation on sulfur emissions.

Perspectives on strategies for improving ultra-deep desulfurization of liquid fuels through hydrotreatment: Catalyst improvement and feedstock pre-treatment

Reliance on crude oil remains high while the transition to green and renewable sources of fuel is still slow. Developing and strengthening strategies for reducing sulfur emissions from crude oil is therefore imperative and makes it possible to sustainably meet stringent regulatory sulfur level legislations in end-user liquid fuels (mostly less than 10 ppm). The burden of achieving these ultra-low sulfur levels has been passed to fuel refiners who are battling to achieve ultra-deep desulfurization through conventional hydroprocessing technologies. Removal of refractory sulfur-containing compounds has been cited as the main challenge due to several limitations with the current hydroprocessing catalysts. The inhibitory effects of nitrogen-containing compounds (especially the basic ones) is one of the major concerns. Several advances have been made to develop better strategies for achieving ultra-deep desulfurization and these include: improving hydroprocessing infrastructure, improving hydroprocessing catalysts, having additional steps for removing refractory sulfur-containing compounds and improving the quality of feedstocks. Herein, we provide perspectives that emphasize the importance of further developing hydroprocessing catalysts and pre-treating feedstocks to remove nitrogen-containing compounds prior to hydroprocessing as promising strategies for sustainably achieving ultra-deep hydroprocessing.