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Molecular dynamics (MD) simulation was carried out to investigate the diffusion behaviors of NH3and flue gases on CeO2-TiO2(CT) catalyst for the selective catalytic reduction of NO with NH3. The influence of temperature, gas mixtures, and slit width of catalyst on the diffusivity of the target molecules were studied. The results showed that both temperature and the competitive diffusion of the target molecules substantially impact gas diffusion within nano-slits. The NH3diffusion was demonstrated to have heightened sensitivity to temperature fluctuations. SO2showed the greatest hindering effect in all of five gases. The negative effect on NH3diffusion was greater when H2O existed in the form of hydroxyl groups. Increasing the slit distance of catalyst significantly mitigated this effect, with a decrease in diffusion impedance from 32.51 % to 5.01 % as the distance expanded from 2.5 nm to 7.5 nm. As for NO, a similar suppressive effect was observed when mixed with SO2, but the influence of hydroxyl groups was notably less pronounced compared to NH3. Specifically, there was only a decrease of 15.14 % at a distance of 2.5 nm, followed by almost no decrease when the distance was increased to 7.5 nm.

Covalent organic framework (COF) membrane materials are being increasingly utilized in gas separation processes due to their low-carbon, clean, and efficient properties. These materials are expected to have large-scale industrial applications in natural gas clean-up and separation processes. The separation effects of COFs materials vary for the CO2membrane separation process, which has a significant impact on gas recovery. This paper aims to compare the mass transfer patterns of different COFs to separate CO2and to expose the mechanism of separation. Employing a combination of Monte Carlo (GCMC) and molecular dynamics (MD) methods, this paper analyzes the mass transfer behaviors of CO2separation from CH4/CO2. The study also examines the thermodynamic parameters, such as separation temperature, separation pressure, and gas components, to reveal the properties of CO2separation from different COFs and the transport rules of gas molecules at the microscopic level. The findings suggest that pore size, CO2concentration, and lower temperature environment contribute to the ability of CO2adsorption. Additionally, COFs with oxygen-containing groups (NUS-2, COF-5, etc.) have better diffusion separation ability, and the AA stacking forms should be maintained during the process of completing the diffusion separation CO2. This paper could provide the essential basis for the design and adjustment of the structure of COFs and the enhancement of the gas membrane separation technology.

Two-step pyrolysis (TSP) of cellulose, hemicellulose, and lignin; the three-component cross-coupling samples; and the acid-washed walnut shell (AWS) were carried out by a pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) to investigate the effects of components and their proportions on the TSP of biomass. The results showed that different components dominated the formation of different products. Cellulose generated more furans and carbohydrates in both the first (S1) and second steps (S2). Hemicellulose achieved higher selectivity of ketones, acids, and alcohols in S1, and higher selectivity of hydrocarbons in S2. Lignin mainly produced phenols in S1, and hydrocarbons and phenols in S2. The increase of holocellulose (hemicellulose and cellulose) improved the contents of aldehydes, ketones, furans, acids, and alcohols but reduced the content of phenols in S1. In S2, more holocellulose increased the contents of aldehydes, ketones, and acids, but decreased the contents of phenols, hydrocarbons, and alcohols. The generation of carbohydrates was strongly inhibited in S1 by hemicellulose and lignin. More cellulose improved the contents of aldehydes, acids, and furans in S1, and increased the content of ketones but reduced the content of acids in S2. Hemicellulose facilitated the generation of hydrocarbons, but inhabited the produce of carbohydrates in S2. The small amount of the low-content components (protein, alkali and alkaline earth metals, etc.) and the connection structure of the components resulted in the significant difference in the pyrolysis reactions and product distribution of AWS and the mixed sample with corresponding component proportion. Therefore, more influence factors, such as the low-content components, the connection structure of the components, and different pyrolysis conditions, should be considered in the near future to investigate the interactions on the two or more components in TSP.

To explore a new way of utilizing lignin and deepen the understanding of mechanism of two-step pyrolysis (TSP) of biomass, the effects of the first step pyrolysis temperature (T1) and residence time (RT1) on TSP of lignin were studied by using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). TSP of lignin was also compared with one-step pyrolysis (OSP) of lignin. The results indicated that higher pyrolysis temperature promoted the break of ether linkage among the structural elements of lignin and the removal of side chains. With T1 increasing, the contents of monophenols (MPs), catechols (CPs), monocyclic aromatic hydrocarbons (MAHs), and polycyclic aromatic hydrocarbons (PAHs) increased in the first step, while the contents of methoxyphenols with double bond in the side-chain (MPBSs) and methoxyphenols with no double bond in the side-chain (MPSs) increased firstly and then decreased. In the second step, with T1 increasing the contents of MPs and CPs increased firstly and then decreased, the contents of MAHs and PAHs increased significantly, and the contents of MPBSs and MPSs decreased. Higher T1 increased the yields of the most identified compounds of the first step, but decreased the yields of MPs, CPs, MPBSs, and MPSs in the second step. RT1 had great effects on the pyrolysis behaviors and product distribution of TSP of lignin, and the content of MAHs and PAHs in the second step increased significantly with RT1 increasing. Compared with OSP, the yields of MAHs and PAHs could increase in the second step. TSP of lignin could improve the selectivity of value-added chemicals remarkably, such as guaiacol, vanillin, acetovanillone in the first step, and the selectivity of benzene, toluene, m-xylene, phenol, o-cresol, and p-cresol in the second step.

A series of 3DOM Cu-Ce catalysts for CO-SCR were prepared by a colloidal template method. Among these catalysts, 3DOM Cu1Ce1catalyst exhibited the best CO-SCR performance (about 100 %) in the widest temperature window (450–700 ℃). Notably, this catalyst still showed excellent stability in the presence of H2O and SO2. It was found that the appropriate molar ratio of Cu and Ce could optimize the pores of Cu-Ce catalysts, and increase their specific surface area. This could contribute to the contact between reaction gas and active sites. The stronger synergistic effect between Cu and Ce could be conducive to the increase of chemisorbed oxygen, and then enhance the redox properties. These might be the key factors for the improvement of 3DOM Cu1Ce1catalytic activity. In addition, the molar ratio of Cu to Ce had a significant influence on the adsorption of CO, which might cause the difference in the consumption of active oxygen and the formation of oxygen vacancies, thus affecting the CO-SCR performance of 3DOM Cu-Ce catalysts.

Pollutant removal and resource recovery from high-humidity flue gas after desulfurization in a thermal power plant are crucial for improving air quality and saving energy. This study developed a flue gas treatment method involving phase transition enhanced by corona discharge based on laboratory research and established a field-scale unit for demonstration. The results indicate that an adequate increase in size will improve the ease of particle capture. A wet electrostatic precipitator is applied before the condensing heat exchangers to enhance the particle growth and capture processes. This results in an increase of 58% in the particle median diameter in the heat exchanger and an emission concentration below 1 mg/m3. Other pollutants, such as SO3and Hg, can also be removed with emission concentrations of 0.13 mg/m3and 1.10 μg/m3, respectively. Under the condensation enhancement of the method, it is possible to recover up to 3.26 t/h of water from 200 000 m3/h saturated flue gas (323 K), and the quality of the recovered water meets the standards stipulated in China. Additionally, charge-induced condensation is shown to improve heat recovery, resulting in the recovery of more than 43.34 kJ/h·m3of heat from the flue gas. This method is expected to save 2628 t of standard coal and reduce carbon dioxide emission by 2% annually, contributing to environmental protection and global-warming mitigation.

The steam-assisted gravity drainage (SAGD) process is effective to improve oil recovery performance, but it also promotes the aquathermolysis reaction of heavy oil under high-temperature reservoir environment. In the present work, a geological model considering core-catalyzed aquathermolysis was established and used to simulate mining in the SAGD process. Results showed that gas generation from aquathermolysis reaction was enhanced by core. Then, the gas production model considering aquathermolysis catalyzed by core was embedded into the geological model. The simulation results show that the main reaction areas of aquathermolysis occurred at the top of the reservoir and the liquid pool near the production well. The steam chamber growth was suppressed, and the simulation results of oil production and cumulative steam–oil ratio were closer to the actual recovery date. By adopting the new model, the recovery situation can be predicted more accurately, so that we can determine the impact of different harvest conditions on the SAGD process.

Condensation fine particles (CFPs) from coal-fired flue gas harm humans and the environment after being emitted into the atmosphere. Given their small size (<0.1 μm), difficulty arises in efficiently removing CFPs by wet electrostatic precipitators and mist eliminators. In this work, a laboratory apparatus was used to study the CFP growth under simulated power plant conditions. Four methods were independently investigated to increase the particle size: addition of ammonia, addition of fly ash, decreasing temperature, and applying an electrical discharge. Results demonstrated that the CFP size distribution possessed a unimodal structure with peak at 0.05 μm. At increased ammonia concentration from 10 to 30 ppm, the peak of growth factor shifted rightward and increased from 1.21 to 1.35 and the range of growth factor >1 was significantly broadened due to joint action of multiple mechanisms. Fly ash acted as the core, and CFPs adhered to the ash surface when forming ash–salt droplets. Cooling flue gas could also enhance the CFP growth due to vapor condensation. At decreased temperature from 45 to 30 °C, the median diameter of CFPs increased by 15%. Finally, the growth and agglomeration of CFPs can be further enhanced when an external electrical field was utilized. The size range of growth factor >1 can be broadened, and the peak growth factor significantly increased at 8 kV applied voltage. The research findings provide valuable guidance for effectively improving the CFP removal efficiency by external regulation for growth enhancement.

Sulfuric acid aerosol (SAA) can considerably deteriorate air visibility, which poses a threat to human health. Pretreatment methods that enlarge SAA sizes are crucial to enhanced emission control from industrials. This study provides an insight into SAA growth in terms of aerosol dynamics simulation and growth experiments under simulated flue gas conditions. Results show that SAA growth dynamics are dominated by coagulation and condensation mechanisms for small and large aerosols, respectively. The two mechanisms are coupled mainly in SAA sizes smaller than 0.05 μm. A large amount of time was allotted for the SAA distribution to grow into an approximately log-normal form without the use of any activation methods. Cooling gas and corona discharge can both enhance SAA growth. Cooling gas is in charge of condensation, whereas corona discharge mainly acts on coagulation. They exhibited 14.3% and 12.3% increases in mean diameter and 12.3% and 69.1% decreases in number concentration. In contrast, adding vapor led to a 1.58% decrease in mean diameter and a 9.4% increase in number concentration. Findings suggest that combining cooling gas and corona discharge to simultaneously promote coagulation and condensation and reduce SAA emission from humid flue gas is possible.

With the implementation of ultra-low emission systems in coal-fired power plants in China, the emission of sulfur trioxide (SO3) has become an important issue in pollution control. However, systematic research and evaluation of SO3control routes based on the existing ultra-low emission systems are still lacking. We assigned 148 coal-fired power plants to four categories based on their ultra-low emission control routes and selected a representative power plant from each category for comprehensive field testing. The results indicated great variability in the synergistic SO3removal capability of different air pollution control devices and routes, resulting in removal efficiencies that ranged from 27% to 94%. Control Route 1, which lacked both a low-low temperature electrostatic precipitator (LLTESP) and a wet electrostatic precipitator (WESP), exhibited the lowest removal efficiency. The two routes equipped with either an LLTESP or a WESP (Control Routes 2 and 3) reduced the SO3concentration in the flue gas produced by medium-sulfur-coal combustion to below 10 mg m−3, whereas Control Route 4, which utilized both an LLTESP and a WESP, reduced the SO3concentration to below 5 mg m−3. Furthermore, sampling the emissions of the 148 power plants revealed that only 14% of the power plants complied with the 5 mg m−3standard for SO3, although 44% and 64% of them complied with the 10 mg m−3and the 20 mg m−3standard, respectively. Our study evaluated the control routes within the context of the whole process, which can guide subsequent research and engineering practices.

The effect of hydrochloric acid treatment on Ce-Ti oxides was investigated for selective catalytic reduction of NO with NH3. The results showed that hydrochloric acid treatment had a positive effect on the low-temperature activity of Ce-Ti oxides. The improved activity of Ce-Ti oxides could be attributed to the increase in the concentration of Ce as well as the amount of Ce3+and chemisorbed oxygen on the catalyst surface. In addition, the enhanced Lewis acidity could improve NH3absorption, and was also a key factor to enhance the low-temperature activity of Ce-Ti oxides.

Particle charging is an essential process for electrostatic precipitators (ESPs) in removing particles. A particle charge measurement system, which can adjust the flue gas temperature, was designed to study the effects of the flue gas parameters (viz., temperature and humidity), particle composition, and discharge electrodes on particle charging. The particle charge increased with the temperature when the applied electric field strength was constant. For particles with a diameter of 0.73 µm, the average charge increased by 30% (from 140 eto 183 e) when the temperature increased from 300 K to 363 K. Furthermore, with a constant electric field strength of –4.2 kV cm–1, the average charge increased by 98% when the relative dielectric constant increased from 4.5 to 11.8. Increased relative humidity significantly accelerated particle charging. For particles > 0.1 µm, the average charge increased by more than 50% when the relative humidity increased from 30% to 80%. Optimizing the discharge electrode also enhanced charging. After the wire electrode (d= 1 mm) was replaced by a ribbon electrode, particle charging increased by more than 75% for 0.7 µm particles at –4.2 kV cm–1.

The current solar organic Rankine cycle power generation (ORC) system cannot run smoothly under the design conditions due to the shortcomings of solar fluctuations, and thermal energy storage (TES) can effectively buffer the fluctuations of solar energy. Cascaded heat storage (CLTES) has been shown to be more suitable for solar heat storage than single-stage heat storage (LTES). The main objective of this study is to analyze the thermal storage characteristics of thermal storage systems under real-time solar energy fluctuations, and to improve the thermal storage efficiency and total thermal storage capacity of solar phase change thermal storage systems in distributed scenarios. The current research on solar CLTES system needs to focus on the heat storage characteristics under the actual solar fluctuations to provide guidance for the design and practical operation of CLTES system. Analyzing the effect of solar fluctuations on thermal storage performance is the focus of solar thermal storage research, which can provide guidance for the design and actual operation of CLTES systems. However, the current research on solar CLTES system lacks the analysis of thermal storage characteristics under typical solar energy fluctuations. Therefore, a simplified two-dimensional enthalpy-dynamic model of heat transfer for shell-and-tube latent heat storage system is developed in this paper to simulate the heat storage characteristics of single-stage and cascade heat accumulators containing different phase change materials (PCMs) at a fixed temperature of the heat source, and the heat storage performance of the system is simulated based on the solar fluctuations of typical four seasons. Finally, based on the shortcomings of large-capacity thermal storage, a dual-tank recirculation thermal storage model is proposed and the thermal storage characteristics of the improved recirculation model are analyzed. The results show that the optimized cycle heat storage mode can bring about a minimum of 10 % and a maximum of 17.2 % thermal efficiency improvement. On a typical summer day with the most abundant solar energy resources, four times of complete phase change heat storage and one incomplete phase change heat storage were completed (melting fraction = 81.83 %), and on a typical winter day with the least solar energy resources, two times of complete phase change heat storage and one incomplete phase change heat storage were completed (melting fraction = 75.81 %). The maximum difference of heat storage between them is 45.38 %.

A wet electrostatic precipitator (ESP) is considered as an effective technology for the control of dust and acid mist after wet flue gas desulfurization. In this study, a lab-scale wet ESP was designed to investigate dust collection with residual SO2in the flue gas. Results showed that dust collection efficiency was reduced in the presence of SO2. This finding is attributed to the sulfuric acid aerosol formation during the corona discharge process. An exponential increase of the aerosol number concentration was observed with the increasing applied voltage, which could be 2 orders of magnitude higher than that without corona discharge. Fractional aerosol size distribution indicated that the aerosol penetration ratio was extremely low, in the size range of 0.1–1.0 μm. The formation of sulfuric acid aerosol could only be detected when the specific energy density exceeded a threshold value. Dust collection efficiency decreased by 13.5% when the SO2concentration increased from 0 to 25 ppm as a consequence of aerosol formation.

The flue gas from waste incineration power plants contains high-level zinc species that may deactivate the catalyst for selective catalytic reduction (SCR) of nitrogen oxides (NOx) with NH3. A comparison experiment was designed to investigate the effect of different types and Zn/Ce molar ratios on the performance of CeO2–TiO2catalysts for the senior undergraduates majoring in energy, environmental, and chemical engineering. This possible inactivation mechanism of CeO2–TiO2SCR catalysts was explored by using X-ray diffraction (XRD), N2adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and in situdiffuse reflectance infrared Fourier transform spectroscopy (DRIFTs). After this comparative laboratory experiment, students can comprehend the principles and processes of SCR technology, learn the preparation methods and characterization of the catalyst, and grasp scientific thinking methods for analyzing and solving a practical problem. Meanwhile, students are guided to realize the environmental issues of industrial processes and understand the limitations of SCR technology. In addition, this comprehensive experiment plays an important role in strengthening students’ experiment skill and solving a practical problem using interdisciplinary knowledge.

The teaching experiment on the catalytic oxidation of volatile organic compounds (VOCs) was designed for senior undergraduate students majoring in energy and power engineering, environmental engineering, and chemical engineering. This teaching experiment enables students to experience a comprehensive scientific inquiry process, including literature research, experimental scheme determination, catalyst preparation, activity evaluation and catalyst characterization, experimental data analysis and discussion, and lab report writing. Students were grouped to prepare Mn–Cu oxide catalysts by different redox precipitation methods and to test the catalytic activities. Moreover, the crystalline phases, pore parameters, micromorphology, and reducibility of the samples were determined by XRD, BET, TEM, and H2-TPR characterization. After the experiment, the students wrote the lab report and the teacher evaluated the students’ performance in the form of scores. The integration of research and teaching was realized by introducing the research project into relevant undergraduate experimental teaching. This experiment could not only deepen the students’ understanding of the hazards of VOCs and catalytic oxidation technology but also stimulate their innovative thinking and practical ability. The experiment is greatly significant in teaching and scientific research.

Aerosols produced in the amine carbon capture process can lead to secondary environmental pollution. This study employs molecular dynamics (MD) simulations to investigate cluster formation, amine behavior, and aerosol growth of amines, essential for reducing amine aerosol emissions. Results showed that the cluster evolution process can be divided into cluster formation and growth in terms of molecular content, and the nucleation rate for the present systems was estimated in the order of 1028cm–3s–1. CO2absorption was observed alongside successful nucleation, with CO2predominantly localizing in the cluster’s outer layer postabsorption. Monoethanolamine (MEA) exhibited robust electrostatic interactions with other components via hydrogen bonding, leading to its migration toward regions where CO2and H2O coexisted within the cluster. While MEA presence markedly spurred cluster formation, its concentration had a marginal effect on the final cluster size. Elevating water content can augment the aerosol growth rate. However, altering the gas saturation is possible only within narrow confines by introducing vapor. Contrarily, gas cooling introduced dual, opposing effects on aerosol growth. These findings, including diffusion coefficients and growth rates, enhance theoretical frameworks for predicting aerosol formation in absorbers, aiding in mitigating environmental impacts of amine-based carbon capture.

Particulate matter (PM) emitted from stationary sources can be classified into filter particulate matter (FPM) and condensable particulate matter (CPM). Because CPM significantly contributes to total emission, a method and an instrument for testing and measuring CPM were developed on the basis of the principle of dilution and condensation. Then, a parallel sampling analysis of CPM and FPM was carried out at the inlet of a desulfurization system and stack of coal-fired units. Results showed that CPM accounted for 76.73% of the total particulate concentration and the removal efficiencies of FPM and CPM were 94.93 and 65.37%, respectively, after wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP). The microscopic morphology, ion concentration, and organic components of CPM were analyzed. CPM was dispersed after formation, and most of them were smaller than 2.5 μm. The main element components were Al, Ca, Na, Fe, Si, C, O, S, F, and Cl. Na+was the most abundant metal cation in the CPM sample. The main parts of the inorganic anions were F–and Cl–. C10–C19and C20–C29were the main components of the alkanes, while the alkanes above C30were only 3.93 and 6.29% at the WFGD inlet and WESP outlet, respectively.

This paper reports a study on the simultaneous removal characteristics of SO3in a wet flue gas desulfurization (WFGD) system. The impacts of the operating parameters, including liquid-to-gas (L/G) ratio, inlet SO3concentration, flue gas temperature, superficial velocity, and slurry temperature, on the SO3removal efficiency and SO3aerosol characteristic were studied. Results showed that the overall SO3removal efficiency varied from 20% to 55% under the experimental conditions. For the SO3aerosol, particles measuring <0.1 μm and >0.5 μm had a higher removal efficiency, whereas particles measuring 0.1–0.5 μm were relatively difficult to remove in the WFGD system. Increases in L/G ratio and SO3concentration exerted positive effects on the SO3aerosol capture, whereas superficial velocity, flue gas temperature, and slurry temperature had negative effects. After installing a sieve plate, the SO3removal efficiency increased from 49.88% and 53.46% to 51.77% and 58.05%, respectively, under two typical conditions. A multilayer perceptron artificial neural network model was applied to evaluate the relative importance of each parameter in SO3removal performance. Results showed that inlet flue gas temperature, inlet SO3concentration, and slurry temperature had a relatively strong impact on SO3removal performance.

The additional use of selective catalytic reduction has increased the amount of SO3generated by coal-fired power plants. Accurate measurement of SO3is of great significance for SO3removal and boiler operation. This work focuses on development and evaluation of an automated continuous monitor designed for SO3measurement in coal-fired flue gases. This instrument is based on selective absorption of SO3in isopropanol and the spectrophotometry determination method with data acquired in real time. Considering that flue gas from a typical power plant could contain high levels of particulate matter (PM), moisture, and SO2, which could interfere with the accuracy of SO3measurement, targeted modifications were made in the design of sampling, determination, and liquid circulation equipment. The accuracy and transient response of the monitor were evaluated in a pilot-scale experimental system with SO3concentrations from 0 to 60 ppm. The interference of SO2in the accuracy of this monitor was also evaluated, and it was shown that the error caused by SO2absorption and oxidization was <0.15% of the SO2concentration. Comparison experiments with the manually controlled condensation method were conducted at high PM concentrations, low PM concentrations, and high SO2concentrations, and they showed that results obtained by the two methods were almost the same. A full-site field application conducted with real flue gas in boilers that burn both high-sulfur and low-sulfur coals showed that the monitor was feasible.

ABSTRACTElectrostatic precipitation is considered as an effective technology for fine particle removal. A lab-scale wet electrostatic precipitator (ESP) with wire-to-plate configuration was developed to study particle migration and collection. The performance of the wet ESP was evaluated in terms of the corona discharge characteristics, total removal efficiency and fractional removal efficiency. The corona discharge characteristics and particle removal abilities of the wet ESP were investigated and compared with dry ESP. Particle removal efficiency was influenced by discharge electrode type, SO2concentration, specific collection area (SCA) and particle/droplet interaction. Results showed that the particle removal efficiency of wet ESP was elevated to 97.86% from 93.75% of dry ESP. Three types of discharge electrodes were investigated. Higher particle removal efficiency and larger migration velocity could be obtained with fishbone electrode. Particle removal efficiency decreased by 2.87% when SO2concentration increased from 0 ppm to 43 ppm as a result of the suppression of corona discharge and particle charging. The removal efficiency increased with higher SCA, but it changed by only 0.71% with the SCA increasing from 25.0 m2/(m3/s) to 32.5 m2/(m3/s). Meanwhile, the increasing of particle and droplet concentration was favorable to the particle aggregation and improved particle removal efficiency.Implications: This work tends to study the particle migration and collection under spraying condition. The performance of a wet electrostatic precipitator (ESP) is evaluated in terms of the corona discharge characteristics, total particle removal efficiency, and fractional particle removal efficiency. The effects of water droplets on particle removal, especially on removal of particles with different sizes, is investigated. The optimization work was done to determine appropriate water consumption, discharge electrode type, and specific collection area, which can provide a basis for wet ESP design and application.

Charging of airborne particle is an important process in both scientific studies and industrial applications, of which the unipolar charging takes up the major part due to higher charging efficiency. In order to understand the charging mechanism of airborne particles, accordingly to predict the efficiency of unipolar chargers, different theoretical models have been proposed and investigated in all regimes. Numerical techniques have been also adopted by researchers to analyze the charging process of airborne particles and thus to model the unipolar chargers. On the other hand, with the advent and application of various measuring techniques, the electric charges measurement of airborne particles was made possible for researchers. In this work, we mainly present a summary of these models, numerical techniques and experimental results on unipolar charging in all regimes, as well as the recent developments in the design of unipolar chargers, trying to briefly overview the development in this research field.

Aerosol emissions from the CO2capture process have a significant impact in terms of solvent loss and environmental pollution. Here, we propose a novel approach with multi-stage circulation for CO2capture and synergistic aerosol reduction, which divides the absorption section into three circulation stages and reduces aerosol emissions through decoupled operation of the three absorption sections and the management of solvent CO2loadings. Experimental results show that with the decoupled management of the liquid–gas ratio and solvent temperature in absorption sections, the aerosol mass concentration at the outlet of the 3rd absorption section can be reduced by 25.6% to a minimum of 349.7 mg/m3at a liquid–gas ratio of 43.2 L/m3and a solvent temperature of 303 K. Furthermore, aerosol removal is performed by setting up a water wash section after the absorption section. The aerosol mass concentration at the outlet of the absorber is reduced to 168.6 mg/m3with the regulation of the wash water temperature and flow rate. In addition, improvements are proposed for the combination of the utilization of recovered solvents and the co-removal of SO2. This study provides innovative insights into the design of the CO2capture system and the reduction of aerosol emissions, which are of great significance for the mitigation of global warming and the control of environmental pollution.

The mitigation of toxic hydrogen sulfide (H2S) in oil field gas is crucial as a result of its significant health and environmental repercussions. This research developed an efficient H2S adsorbent using oil sludge, a hazardous waste of oil production, by adding the alkaline activator KOH before pyrolysis. The performance of the adsorbent was assessed with a fixed bed in humid gas conditions. The adsorption kinetics were characterized theoretically, and reaction pathways were subsequently proposed. Results showed that the adsorbent activated by KOH presented a higher desulfurization capacity than those activated by NaOH, Na2CO3, and K2CO3. The addition of KOH increased the volume of the mesopores and the content of surface active sites. However, an optimal KOH concentration emerged when assessing the desulfurization capacity concerning the mass of the adsorbent or activator. The kinetic investigations revealed that the H2S adsorption process obeyed the Langmuir model and was modulated by both external diffusion and internal diffusion. In addition, the role of KOH during the H2S adsorption process was identified through the analysis of desulfurization products on the deactivated adsorbent. As a result of being catalyzed by KOH, elemental sulfur was oxidized to high-valent sulfuric acid and neutralized to sulfate. This research provides innovative perspectives on devising economical oil-sludge-based adsorbents, facilitating the concurrent processing of oil field gas and oil sludge in oilfield operations.

Aerosol emission from the CO2capture system has raised great concern for causing solvent loss and serious environmental issues. Here, we propose a comprehensive method for reducing aerosol emissions in a CO2capture system under the synergy of aerosol formation inhibition and wet electrostatic precipitation. The gas–solvent temperature difference plays a vital role in aerosol formation, with aerosol emissions of 740.80 mg/m3at 50 K and 119.36 mg/m3at 0 K. Different effects of SO2and SO3on aerosol formation are also found in this research; the aerosol mass concentration could reach 2341.25 mg/m3at 20 ppm SO3and 681.01 mg/m3at 50 ppm SO2with different aerosol size distributions. After the CO2capture process, an aerosol removal efficiency of 98% can be realized by electrostatic precipitation under different CO2concentrations. Due to the high concentration of aerosols and aerosol space charge generated by SO2and SO3, the removal performance of the wet electrostatic precipitator decreases, resulting in a high aerosol emission concentration (up to 130.26 mg/m3). Thus, a heat exchanger is installed before the electrostatic precipitation section to enhance aerosol growth and increase aerosol removal efficiency. Under the synergy of aerosol formation inhibition and electrostatic precipitation, an aerosol removal efficiency of 99% and emission concentrations lower than 5 mg/m3are achieved, contributing to global warming mitigation and environmental protection.

Superheated steam‐enhanced steam‐assisted gravity drainage (SSE‐SAGD) is a promising enhanced oil recovery method. However, the existence of aquathermolysis reactions makes the development process more complex. In this paper, the application potential of SSE‐SAGD in an oilfield was analyzed based on the estimated oil recovery and the production cost. A numerical model with aquathermolysis reactions was established, and after the model validation, the effects of steam superheats on the steam chamber's expansion were analyzed by taking the heat loss into account. Subsequently, the cumulative enthalpy‐oil ratio (cEOR) was introduced to characterize the production cost. The results show that as the superheat degree increased, the recovery factor was improved, but the cEOR increased simultaneously. Comparing with saturated steam, the superheated steam with a superheat of 50 ° led to a 16.42% increase in oil production and a 7.11% increase in cEOR. We proposed a new development scheme with a step increasing in superheat to weaken the impact of aquathermolysis reactions. The scheme achieved a 12.82% increase in oil production at a 3.93% increase in cEOR over saturated steam injection. Our findings could provide new insights in the use of superheated steam to enhance SAGD. The specific heat of superheated steam varies widely. Herein, a novel indicator named cumulative enthalpy−oil ratio is proposed to evaluate the production cost accurately. Then, the application potential of superheated steam‐enhanced steam‐assisted gravity drainage is analyzed considering the aquathermolysis reactions. Finally, an optimization scheme is provided to balance the oil recovery and the production cost.