Effects Of Operating Parameters Research Articles

Solar-Induced Photocatalytic Degradation of Reactive Red and Turquoise Dyes Using a Titanium Oxide/Xanthan Gum Composite

The present study explores the solar-induced photocatalytic degradation of reactive red (RR) and reactive turquoise (RT) dyes in a single system using TiO2 immobilized in xanthan gum (TiO2/XG), synthesized using the sol–gel dip-coating technique for direct precipitation. SEM-EDX, XRD, FTIR, and UV–Vis were used to assess the characteristics of the resulting catalyst. Moreover, the effects of different operating parameters, specifically pH, dye concentration, TiO2/XG concentration, H2O2 concentration, and contact time, were also investigated in a batch photocatalytic reactor. The immobilized TiO2/XG catalyst showed a slight adsorption degradation efficiency and then improved the RR and RT dye degradation activity (92.5 and 90.8% in 120 min) under solar light with a remarkable Langmuir–Hinshelwood pseudo-first-order degradation rate of 0.0183 and 0.0151 min−1, respectively, under optimum conditions of pH 5, dye concentration of 25 mg/L, TiO2/XG concentration of 25 mg/L, H2O2 concentration of 400 mg/L, and reaction time of 120 min. The improved photocatalytic ability was ascribed to the impact of TiO2/XG nanoparticles with a high surface area, and lower band gap energy. Solar light energy has significant potential for addressing energy deficit and water pollution concerns.

Effect of operational parameters on the performance of an anaerobic sequencing batch reactor (AnSBR) treating protein-rich wastewater

Treating protein-rich wastewater using cost-effective and simple-structured single-stage reactors presents several challenges. In this study, we applied an anaerobic sequencing batch reactor (AnSBR) to treat protein-rich wastewater from a slaughterhouse. We focused on identifying the key factors influencing the removal of chemical oxygen demand (COD) and the settling performance of the sludge. The AnSBR achieved a maximum total COD removal of 90%, a protein degradation efficiency exceeding 80%, and a COD to methane conversion efficiency of over 70% at organic loading rates of up to 6.2 g COD L−1 d−1. We found that the variations in both the organic loading rate within the reactor and the hydraulic retention time in the buffer tank had a significant effect on COD removal. The hydraulic retention time in the buffer tank and the reactor, which determined the ammonification efficiencies and the residual carbohydrate concentrations in the reactor liquid, affected the sludge settleability. Furthermore, the genus Clostridium sensu stricto 1, known as protein- and lipids-degraders, was predominant in the reactor. Statistical analysis showed a significant correlation between the core microbiome and ammonification efficiency, highlighting the importance of protein degradation as the governing process in the treatment. Our results will provide valuable insights to optimise the design and operation of AnSBR for efficient treatment of protein-rich wastewater.

Revealing impacts of operational modes on anaerobic digestion systems coupling with sulfate reduction

Anaerobic digestion (AD) is promising for treating high-strength wastewater. However, the effect of operational parameters on microbial communities of AD with sulfate is not yet fully understood. To explore this, four reactors were operated under rapid- and slow-filling modes with different organic carbons. Reactors in the rapid-filling mode generally exhibited a fast kinetic property. For example, the degradation of ethanol was 4.6 times faster in ASBRER than in ASBRES, and the degradation of acetate was 11.2 times faster in ASBRAR than in ASBRAS. Nevertheless, reactors in the slow-filling mode could mitigate propionate accumulation when using ethanol as organic carbon. Taxonomic and functional analysis further supported that rapid- and slow-filling modes were suitable for the growth of r-strategists (e.g., Desulfomicrobium) and K-strategists (e.g., Geobacter), respectively. Overall, this study provides valuable insights into microbial interactions of AD processes with sulfate through the application of the r/K selection theory.

Combined Effect of Operating Parameters and Nanoparticles on the Performance of a Diesel Engine: Response Surface Methodology-Coupled Genetic Algorithm Approach.

This paper's goal is to ascertain the optimum input parameters and nanoparticle concentrations for least emission and better performance by utilizing the genetic algorithm (GA) and response surface methodology (RSM) in a single-cylinder diesel engine running with 20% blend of biodiesel derived from Manilkara zapota seeds. Experiments to be conducted on the engine were designed with a central composite design (CCD) with input parameters of loads (20-100%), nanoparticle concentrations (NPCs, 0-80 ppm), compression ratios (CRs, 16.5-18.1), injection pressures (IPs, 190-230 bar), and injection timings [ITs, 17-29° bTDC (before top dead center)], and the engine response was recorded. The comparative analysis of optimization tools RSM and GA was employed for finding the ideal setting of engine input parameters and nanoparticle concentrations based on the maximization of performance [brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC)] and minimization of emissions [(hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxides (NOx)]. The best result was obtained by the RSM method. The optimized input parameters were recorded at a load of 59.36%, an NPC of 80 ppm, a CR of 18.1, an IP of 192.02 bar, and an IT of 18.62° bTDC. At these optimized settings, the performance and emissions were 32.4767% BTE, 0.1905 kg/kW h BSFC, 26.8436 ppm HC, 0.0272% CO, and 83.854 ppm NOx emissions from the engine. The developed model was validated through a confirmatory experiment, and the prediction error was within 8%. Thus, the applied model is appropriate for improving the engine's emission and performance attributes.

Optimization of oil extraction from Carica papaya seedoil: A case of response surface methodology

The primary goal of this research is to determine the optimum value oil and to determine the effects of operational parameters on the physiochemical properties of the Carica papaya seed oil, such as Mean Molecular mass, viscosity, API, Acid value, Free Fatty Acid (%FFA), Peroxide value, Saponification value, Iodine value, moisture content, Specific gravity, Cetane number and Higher Heating value (HHV). Respond Surface Methodology (RSM) was used for regression analysis, ANOVA and to also predict the optimal value for the Carica papaya seed oil extracted. The model was created to be significant, according to the results, and a quadratic polynomial was achieved for forecasting the extraction procedure. The highest yield obtained was 23.67% (w/w) at the sample weight (55 g) the physicochemical properties of the extracted papaya seed oil, provided papaya seed oil with obviously reddish brown color, density 955kg/m3, specific gravity 0.9235, moisture content 0.004092% acid value 27.974 mg KOH/g, % FFA 13.99, saponification value 140.25 mg KOH/g oil, iodine value 93.70, peroxide value 56.00 meq O2/kg oil, viscosity 622.1 MPa.S at 29.6oC, Cetane number 82.88, diesel value 101.22, Higher Heating value, (HHV) 29.62325MJ/kg, Mean Molecular Mass 399.3, API 21.72, aniline point 466.03. The Carica papaya seed is rich in oil and gave a high quantity of oil, using Respond Surface Method it yielded 23.67% (w/w) archived at the following optimized conditions, sample weight (55 g), extraction time (50 min), and solvent volume of 250 ml, the values for coefficient of determination (R2) for RSM 0.9835, respectively. The research concluded that papaya seed oil is rich in oil which can be applied as a major feedstock in industries.

Synergistic analysis for co-treatment of poultry wastewater and sewage in electro-chemical system: Operational parameters, kinetics and energy estimation

This research deals with the investigation of poultry wastewater (PW) treatment by electrocoagulation (EC) using iron (Fe) and stainless-steel (SS) electrodes for COD, NO3− and TSS removal. Meanwhile, effect of operational parameters i.e. treatment time (0–180 min), voltage (5–30 V), pH (3-11), number of electrodes (2–6), electrode combination (Fe−SS−Fe−SS and SS−Fe−SS−Fe) and electrode spacing (1–3 cm) on removal of COD, NO3− and TSS were investigated. Subsequently, first-order and second-order kinetic models were adopted for determining rate constants. Furthermore, the efficacy of potential application of EC technique for cotreatment of PW and sewage (SW) at different volumetric ratios PW + SW (mL + mL) viz. 1000 + 0, 800 + 200, 600 + 400, 400 + 600 and 0 + 1000 was examined. From results, it was observed that optimum operating conditions were found to be 120 min, 25 V voltage, 4 electrodes and 1 cm electrode distance at neutral pH. At optimized conditions, Fe electrodes were found to be more efficient in COD (99%), NO3− (85%) and TSS (89%) removal of comparison to SS electrodes (COD (84%), NO3− (71%) and TSS (72%)). Furthermore, synergistic index and electrical energy order elucidated the feasible application of EC treatment using Fe electrode for co-treatment of PW + SW efficiently.

Process optimization of a moving bed bioreactor undergoing simultaneous nitrification and denitrification for wastewater in the absence of organic carbon

ABSTRACT Moving bed bioreactors are efficient for the removal of nitrogen effluents by simultaneous nitrification and denitrification (SND), which is particularly challenging for effluents with low C/N ratio due to insufficient carbon available for denitrification. The addition of external organic carbon in such cases increases treatment costs. Endogenous degradation of biomass offers a cost-effective and persistent source of carbon. Internal carbon leads to low denitrification rates and optimizing the biomass content leads to a sustainable solution for treating such effluents. The present study aims to optimize the process of SND using endogenous carbon by investigating the effect of operational parameters like dissolved oxygen, influent ammonium (NH4–N) loading, hydraulic retention time (HRT) and carrier filling ratio (CFR). The synthetic wastewater used in the study does not inherently contain any organic carbon, thus indicating the responsible carbon for denitrification to be of internal origin. Using a novel carrier for multispecies biofilm development, initial NH4–N concentration variation showed an insignificant effect on SND efficiency. At higher loading, nitrite accumulation due to incomplete denitrification was observed. The effect of CFR was investigated in a range of 20–35%, beyond which non-homogeneous mixing was caused in the reactor. Under controlled DO and temperature of about 5 mg/L and 28 ± 2°C, respectively, an optimum filling ratio of 35% was finalised, resulting in an SND efficiency of 97.9% at 22 h HRT for high influent NH4–N concentration of 500 mg/L. Bacteriological species identification revealed the coexistence of nitrogen-fixing, aerobic nitrifying and anaerobic denitrifying bacteria in the biofilm growing on the biocarrier. Mechanism of SND occurring in aerobic moving bed bioreactors: Laboratory-scale aerobic Moving Bed Bioreactor setup for a continuous study evaluating the influence of operational parameters on SND Occurrence of aerobic and anoxic zones in biofilm grown on the surface of novel carriers due to diffusional gradient of dissolved oxygen

Some approximations on the effect of the supporting electrolyte towards electrochemical advanced oxidation degradation of Reactive Orange 84 (RO84)

In this paper, some advanced oxidation electrochemical processes such as anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) to carry out the degradation of the azo dye Reactive Orange 84 (RO84) are presented. For this, boron-doped diamond (BDD) electrodes were used, and different configurations were taken in a stirred tank cell, like BDD/graphite and BDD/BDD. The effect of different operating parameters on the discoloration process was evaluated, including the concentration of the supporting electrolyte, namely 50 and 75 mM of Na2SO4, along with 50 mM NaCl and mixtures of Na2SO4 + 25 mM NaCl. The effect of the applied current density at 25, 50, and 100 mA cm−2 over the loss of color was also analyzed using initial RO84 concentrations of 100 and 200 mg/L. The production of free radicals was evaluated in the bulk solution. The decrease in chemical oxygen demand (COD) was determined and the evolution of oxalic acid, a nontoxic, short-chain carboxylic acid was quantified as a final product of all treatments by using ion-exclusion high-performance liquid chromatography.

Ultra-efficient removal of methylene blue, oxytetracycline, and lead(II) by activated carbon derived from black cumin (Nigella sativa) processing solid waste

Accumulating dyes, drugs, and heavy metals in water creates a lasting environmental problem that affects living things in different ecosystems. Their removal is imperative for environmental necessity in a habitable world. Adsorption with carbonaceous materials produced especially for the evaluation of agricultural wastes is a low-cost and effective removal technique. This study is related to the investigation of the adsorbing performance of a new activated carbon (BAC) synthesized from black cumin (Nigella sativa) processing solid waste (BW) under optimal conditions determined by single-step carbonization/activation with potassium carbonate to remove methylene blue, oxytetracycline, and lead (II) in an aqueous medium. Their optimum adsorption conditions were decided based on the maximum effects of important operational parameters. Experimental kinetic and isotherm findings for each adsorption system were modeled by evaluating widely used kinetic and isotherm equations. The maximum adsorption capacity of BAC was determined as 752 mg/g for methylene blue, 911 for oxytetracycline, and 556 mg/g for lead (II) from the Langmuir isotherm model. The thermodynamic parameters determined showed that the adsorption processes were self-occurring and also endothermic for methylene blue and oxytetracycline and exothermic for lead(II). In addition, BAC showed stability and recyclability in adsorption-desorption cycles for the pollutants studied. These findings suggest that BAC can be used as an ultra-efficient adsorbent for larger-scale wastewater treatment.

Performance evaluation of a two-stage air-cooled silica gel + water adsorption cooling system: Effect of key operational parameters

The primary objective of this work is to extract some design criteria of the upper-stage adsorber bed in a two-stage two-bed adsorption cooling system. The second objective is to experimentally investigate the effects of air-cooled heat sink, and hot water source temperatures on the chiller performance. These studies are important as the adsorber bed design together with the input operational parameters determines the chiller performance. It was observed that the performance indicators, namely, cooling capacity (CC) and coefficient of performance (COP) exhibit opposite trends with the reduction in the temperature of the sink where heat of adsorption is rejected. The performance parameters are evaluated for heat source temperatures in the range of 75–85 °C against different half-cycle times. The CC and COP are found to vary between 148 - 324 W and 0.09–0.11 respectively depending on the heat source temperature and half cycle time. The novelty of the present work is in providing experimental evidence on influence of heat source temperatures on two-stage adsorption chillers when air cooling is adopted for all heat rejections to the ambient. Another key finding is that the upper stage performance is critical because of smaller volume and lower heat transfer area available in it compounded by higher uptake differences across which it operates.

Numerical Study of Dry Reforming of Methane in Packed and Fluidized Beds: Effects of Key Operating Parameters

Replacing the conventionally used steam reforming of methane (SRM) with a process that has a smaller carbon footprint, such as dry reforming of methane (DRM), has been found to greatly improve the industry’s utilization of greenhouse gases (GHGs). In this study, we numerically modeled a DRM process in lab-scale packed and fluidized beds using the Eulerian–Lagrangian approach. The simulation results agree well with the available experimental data. Based on these validated models, we investigated the effects of temperature, inlet composition, and contact spatial time on DRM in packed beds. The impacts of the side effects on the DRM process were also examined, particularly the role the methane decomposition reaction plays in coke formation at high temperatures. It was found that the coking amount reached thermodynamic equilibrium after 900 K. Additionally, the conversion rate in the fluidized bed was found to be slightly greater than that in the packed bed under the initial fluidization regime, and less coking was observed in the fluidized bed. The simulation results show that the adopted CFD approach was reliable for modeling complex flow and reaction phenomena at different scales and regimes.

Photo-Oxidation in Three-Phase Flow with Continuous Photosensitizer Recycling

Microreactors have emerged as a promising platform for conducting photo-oxidations, offering green routes to facilitate significant chemical transformations. In this study, the sustainability of photo-oxidations is improved by a three-phase gas/liquid/liquid flow reaction in a photo-microreactor with continuous recycling, which is applied to a model reaction. Recycling is enabled by the photosensitizer and the substrate, which are in immiscible phases. The effect of various operational parameters on the reaction and the contact pattern among phases is explored, and the interplay between the flow pattern and photo-oxidation is discussed. The highest conversion is detected for flow conditions that display significantly lower diffusion distance between the dispersed photosensitizer slug and the oxygen bubble, highlighting the link between the flow pattern and mass transfer. Furthermore, phase separation was automated using a liquid–liquid separator where the photosensitizer and organic substrate were recycled continuously to achieve full conversion. The proposed approach eliminates the downstream purification step and provides a sustainable pathway toward photo-oxidations in microreactors.

Operation analysis and its performance optimizations of the spray dispersion desulfurization tower for the industrial coal-fired boiler

As a relatively new type of desulfurization system, long-term high-efficiency desulfurization is a critical issue for commercial spray dispersion system applications. To analyze the coupling effects of different operation parameters, a series of operation performance predictions with their optimizations are implemented. Through the analysis of the operating influencing factors based on artificial intelligence, the key influencing factors of the operation performance are determined. For instance, the tube immersion depth accounts for 46% of the factors that affect the desulfurization efficiency. Moreover, the system stability analysis determines not only the system's fine operation stability, but also identifies several factors, such as the PH and inlet gas temperature, that require key control for operational stability. For instance, the phase margin of the PH, flue gas temperature, and SO2 concentration in flue gas is greater than 0 when the amplitude margin reaches 1 point, allowing the PH control system to demonstrate excellent system operating stability. Then, after a systematic analysis of the operation, several optimizations of the operation are provided. Finally, in recent applications, the optimized spray dispersion has demonstrated excellent desulfurization performance: the desulfurization efficiency was greater than 99%, and the outlet SO2 concentration was less than 15 mg/m3 in three years of operation, which means that near-zero SO2 emissions in long cycles were essentially achieved, and 1/3 and 1/5 of the energy and cost consumption were reduced.

Optimization of Process Parameters for Pellet Production from Corn Stalk Rinds Using Box–Behnken Design

In the current study, corn stalk rinds were used as feedstock for the production of solid-fuel pellets. In an effort to comprehensively analyze the effects of different operational parameters on the physical properties of pellets, response surface methodology (RSM) was employed in conjunction with a Box–Behnken experimental design (BBD). By assessing multiple variables simultaneously and examining their interactions, BBD facilitates the development of a reliable response model that can predict how changes in independent variables will impact response variables. The recorded responses included relaxed density, mechanical durability, and compressive strength. Based on the results, greater R2 values of 0.9467, 0.8669, and 0.9196, could be, respectively, attained for the quadratic regression models. The analysis of variance revealed that all independent variables had significant effects on the responses. The optimal processing condition for the pellets was established by determining the ideal combination of operational parameters. The process entailed the choice of a particle dimension measuring 0.5 mm, a moisture level of 11.35%, the application of heat at 125.7 °C on the die, and the utilization of a molding pressure of 154.2 MPa. Based on these factors, the predicted response values were determined to be 1639.61 kg/m3 for relaxed density, 97.95% for mechanical durability, and 10.18 MPa for compressive strength. The values obtained experimentally under the optimized conditions were similar to the predicted values with a desirability value of 1.00.

Tri-objective optimization of a waste-to-energy plant with super critical carbon dioxide and multi-effect water desalination for building application based on biomass fuels

In the present research, an innovative biomass-based energy system for the production of electricity and desalinated water for building application is proposed. The main subsystems of this power plant include gasification cycle, gas turbine (GT), supercritical carbon dioxide cycle (s-CO2), two-stage organic Rankine cycle (ORC) and MED water desalination unit with thermal ejector. A comprehensive thermodynamic and thermoeconomic evaluation is performed on the proposed system. For the analysis, first the system is modeled and analyzed from the energy point of view, then it is examined similarly from the exergy point of view, and then an economic analysis (exergy-economic analysis) is performed on the system. Then, we repeat the mentioned cases for several types of biomasses and compare them with each other. Grossman diagram will be presented to better understand the exergy of each point and its destruction in each component of the system. After energy, exergy and economic modeling and analysis, the system is analyzed and modeled using artificial intelligence to help the system optimization process, and the model obtained with genetic algorithm (GA) to maximize the output power of the system, minimize the cost system and maximizing the rate of water desalination is optimized. The basic analysis of the system is analyzed inside the EES software, then it is transferred to the MATLAB software to optimize and check the effect of operational parameters on the thermodynamic performance and the total cost rate (TCR). It is analyzed and modeled artificially and this model is used for optimization. The obtained result will be three-dimensional Pareto front for single-objective and double-objective optimization, for work-output-cost functions and sweetening-cost rate with the specified value of the design parameters. In the single-objective optimization, the maximum work output, the maximum rate of water desalination, and the minimum TCR will be 55,306.89 kW, 17216.86 m3/day, and $0.3760/s, respectively.

Construction of Ag/Ag2S/CdS Heterostructures through a Facile Two-Step Wet Chemical Process for Efficient Photocatalytic Hydrogen Production

We have demonstrated a two-step wet chemical approach for synthesizing ternary Ag/Ag2S/CdS heterostructures for efficient photocatalytic hydrogen evolution. The CdS precursor concentrations and reaction temperatures are crucial in determining the efficiency of photocatalytic water splitting under visible light excitation. In addition, the effect of operational parameters (such as the pH value, sacrificial reagents, reusability, water bases, and light sources) on the photocatalytic hydrogen production of Ag/Ag2S/CdS heterostructures was investigated. As a result, Ag/Ag2S/CdS heterostructures exhibited a 3.1-fold enhancement in photocatalytic activities compared to bare CdS nanoparticles. Furthermore, the combination of Ag, Ag2S, and CdS can significantly enhance light absorption and facilitate the separation and transport of photogenerated carriers through the surface plasma resonance (SPR) effect. Furthermore, the Ag/Ag2S/CdS heterostructures in seawater exhibited a pH value approximately 2.09 times higher than in de-ionized water without an adjusted pH value under visible light excitation. The ternary Ag/Ag2S/CdS heterostructures provide new potential for designing efficient and stable photocatalysts for photocatalytic hydrogen evolution.

Self-rotation induced regeneration of filter media to enhance the oil-water separation in a microchannel filter

The regeneration of filter media was crucial to the filtration performance of the oily wastewater. Herein, a novel hydrocyclone-induce approach was proposed for filter media regeneration, followed by an exploration of oil desorption feasibility and mechanism. The effect of structural and operation parameters of a hydrocyclone on the particle self-rotation was extensively analyzed by numerical simulation, and its feasibility for oil desorption from the filter media was subsequently investigated. A hydrocyclone-intensified filtration method that combined by the unit of filtration and hydrocyclone self-rotation regeneration was proposed, and the effect of hydrocyclone-induced filter media regeneration on the subsequent oily wastewater filtration was also explored. The ideal specifications of the hydrocyclone were concluded to be an overflow pipe insertion of 120 mm, and a cone angle of 60° for the optimal self-rotation velocity. The hydrocyclone-induced regeneration presents a remarkable oil desorption efficiency, and the oil concentration of filter media reduced from 9.43 % to 6.94 %, 4.33 %, and 3.43 % as the flowrate increased from 1.8 × 105 L·m−2·h−1 to 5.4 × 105 L·m−2·h−1. The adhered oil was exfoliated due to the centrifugal force caused by the revolution and self-rotation of the media particles, while the filter media spun in a hydrocyclone. The average effluent oil concentration in the raw oily wastewater was reduced to 12.2 mg/L during the pilot-scale test, indicating that the hydrocyclone regeneration benefits the continuous oil-water separation. It is believed that this work might provide a unique and efficient method for oily wastewater treatment with the integration of filtration and hydrocyclone regeneration.

Anion exchange membrane water electrolysis: Numerical modeling and electrochemical performance analysis

In this paper, a three-dimensional numerical model is developed for an anion exchange membrane electrolyser cell (AEMEC) with a double serpentine flow field pattern. The focus on the AEMEC is due to its benefits, including the solid membrane, inexpensive catalysts and membrane, and high stability. The effect of important operating parameters, i.e. cell temperature and cathode pressure, on the performance of the electrolyser is numerically modeled by considering different causes of performance degradation. The polarization curve, uniformity index, and the distribution of the hydrogen concentration, current density, temperature, and pressure in different operating conditions are presented. By increasing the operating temperature and decreasing the cathode pressure, the voltage of the elctrolyser decreases. Due to the higher concentration of water at the inlet of the cathode channel, more hydrogen is produced, and the current density is higher. The maximum current density and hydrogen concentrations are 7868Am2 and 0.898molm3, respectively, when the operating condition is set to the temperature of 343 K, the pressure of 1 bar, and the cell voltage of 1.85 V.

Thermal-hydraulic-mechanical-chemical modeling and simulation of an enhanced geothermal system based on the framework of extended finite element methods - Embedded discrete fracture model

The thermo-hydro-mechanical-chemical (THMC) coupling process plays a crucial role in Enhanced Geothermal System (EGS), particularly during long-term heat extraction. However, most models for fractured reservoirs are computationally expensive, with very dense grids required, especially near fractures, limiting their practical use in EGS research. The embedded discrete fracture model (EDFM) can construct fracture and matrix grids independently, significantly reducing computational complexity while maintaining high accuracy. Although it is suitable for efficiently evaluating the long-term performance of heat extraction in fractured reservoirs, there are few THMC-coupled models based on EDFM, and THMC coupling effects have often been overlooked in evaluations of the environmental benefits of EGS. To address this, a fully THMC-coupled model based on EDFM and the extended finite element method (XFEM) is proposed and verified. The evolution of heat production and environmental benefits of an EGS over 30 years are presented. The results show that the production temperature and electric power remain highly efficient in the first 5 years and decrease by 7.8% and 15.4% respectively over 15 years. Moreover, the total amount of extracted heat during this period is 6.52 × 1012 kJ, which is equivalent to saving 22.26 × 108 kg of coal consumption and reducing CO2 emissions by 5.83 Mt, SO2 emissions by 189.22 × 105 kg, and NOx emissions by 166.96 × 105 kg. These findings highlight the significant potential of geothermal energy for energy supply and environmental benefits. Additionally, the study investigates the effects of critical operating and physical parameters on the production performance of EGS, including injection temperature, injection flow rate, initial reservoir temperature, and initial reservoir permeability. This work serves as a reference for both the theoretical THMC coupled model and practical EGS engineering.

Lipid extraction and CO2 capture with switchable polarity solvent

In this study, lipid extraction and CO2 capture are combined using N, N-dimethylcyclohexylamine (DMCHA) as switchable polarity solvent. The effects of operation parameters are discussed according to the CO2 absorption/desorption and lipid/DMCHA recovery results. A triphasic models considering lipid, water, and gas phases are established to analyze the kinetic behaviors. The results show that DMCHA is reversible through CO2 absorption/desorption, and the enhanced dispersion of droplets and bubbles in water phase improves the lipid/DMCHA recovery and CO2 absorption/desorption. The triphasic kinetic models fit well with experimental data, and gas–liquid mass transfer is regarded as the rate-determining step. The lower interfacial areas result in the poorer gas–liquid mass transfer for the DMCHA recovery than lipid recovery process.