Recovery Efficiency Research Articles

Experimental study of four-step thermal swing adsorption cycle to upgrade biogas obtained from anaerobic digestion

Biogas is a renewable source of energy that when upgraded can be adopted as a reliable and sustainable alternative. This study evaluates the performance of thermal swing adsorption technology applying resistive heating, in upgrading biogas obtained from anaerobic digestion to biomethane. Commercial coconut shell-based activated carbon was used as an adsorbent in the four-step cycle process to capture carbon dioxide, using a fabricated adsorption model. The influence of minor gas constituents of biogas in carbon dioxide breakthrough curves was analyzed. Dynamic adsorption tests were carried out to evaluate the system performance in carbon dioxide capture. The maximum regeneration temperature of 60 ℃ was found to have peak carbon dioxide concentration of 39% in the waste gas, maximum energy requirements of 0.1538kWh per cycle, and an energy efficiency of 87%. This is a good trade-off between adsorbent recovery and system energy efficiency. The adoption of thermal swing adsorption technology in biogas upgrading systems is a viable alternative for water-deficient regions.

Recovering chromium from electroplating sludge using an integrated technology of bipolar membrane electrodialysis and H2O2 oxidation

Chromium electroplating produces Cr(III)-containing electroplating sludge (EPS) in large volumes, which is easily oxidised to Cr(Ⅵ) and is harmful to the environment and human health. This study recovered Cr(III) as Na2CrO4 from EPS using an integrated bipolar membrane electrodialysis (BMED)–H2O2 oxidation technology. During the treatment process, Cr(III) was oxidised to Cr(VI) using H2O2 in an alkaline environment, BMED was used to separate and recover Cr(VI). Experimental results showed that H2O2 dosage and pH affected Cr(III) oxidation—the highest Cr(III) oxidation ratio of 68.4% was observed when H2O2 dosage and pH were 5.5 mL and 12.0, respectively. The current density, solid/liquid ratio and sludge particle size affected Cr(III) recovery, energy consumption and current efficiency. Under a current density of 20.0 mA/cm2, solid/liquid ratio of 1.0:45 and sludge particle size of 100 mesh, 58.2% of Cr(III) was recovered. When the number of the equipped EPS compartments was increased from one to two and three, the specific energy consumption decreased from 1.04 to 0.87 and 0.81 kW h/g, respectively, but the current efficiency remained almost constant. After EPS treatment, the Cr(III) remaining in the sludge was mainly in the residual state, which is less environmentally harmful. The obtained Na2CrO4 had similar properties according to X-ray diffraction analysis. Thus, the proposed integrated technology effectively recovers Cr(III) from EPS and other chromium-containing solid wastes.

Fabrication of visible light responsive BaFe12O19/Ag/AgI composites with enhanced photocatalytic degradation of organic pollutants

A novel visible-light-driven (VLD) BaFe12O19/Ag/AgI photocatalysts were constructed through calcination and hydrothermal methods, in which BaFe12O19 of different mass ratios were introduced. The constructed Z-scheme heterojunction provided BaFe12O19/Ag/AgI composite catalytic with effective space carrier transport and higher redox ability. In particular, the as-prepared BaFe12O19/Ag/AgI degraded nearly 94% of 2- mercaptobenzothiazole within 30minutes of visible-light illumination, which was much superior to that of pure AgI (47%) and BaFe12O19 (3%). Moreover, BaFe12O19/Ag/AgI can be easily magnetically separated, so as to facilitate its efficient separation and recovery in practical application. Photocatalytic activity assays revealed that the as-synthesized BaFe12O19/Ag/AgI also exhibited good photodegradation capability towards Imidacloprid, Tetracycline and Carbamazepine. In particular, the complex had relatively high oxygen activation ability, and its photocatalytic H2O2 production performance was 1.29 times higher than that of the AgI monomer within 120minutes, thus realizing rapid water disinfection. Overall, the constructed efficient Z-scheme BaFe12O19/Ag/AgI photocatalysts provide a novel insight in sewage purification.

Recovery of precious metals from aqua regia leachate of E-wastes using dithiocarbamate-modified cellulose and development of novel kinetic model

The escalating demand and dwindling natural supplies of precious metals (PMs) necessitate innovative hydrometallurgical recovery approaches with rapid kinetics and reduced environmental impact. The current study investigated the sorption and recovery of PMs from electronic waste (e-waste) utilizing dithiocarbamate-modified cellulose (DMC) and its proline derivative with epoxy cross-linkage (DMC-Pro-Epo-6) in aqua regia (AR). The effects of various sorption parameters, such as sorbent dose in feed, HCl: HNO3 ratio, AR dilution times, etc., on PM recovery were explored. Equilibrium for AuIII and PtIV sorption by DMC and DMC-Pro-Epo6 was reached in less than an hour, which is significantly faster than most reported sorbents. The maximum sorption capacities, calculated using the Langmuir equation, were 348.0 mg g−1 for AuIII and 34.7 mg g−1 for PtIV for DMC, while DMC-Pro-Epo6 achieved 350.3 mg g−1 for AuIII and 31.1 mg g−1 for PtIV. These capacities, particularly for the higher sorption capacity of AuIII by DMCs, are attributed to the relativistic effects of gold, soft–soft interactions, and strong sulfur binding. FT-IR, FE-SEM, and EDX analyses elucidated the chelation bonding and mechanisms involved in PM sorption onto DMCs. By utilizing AR-DMC integrated techniques, step-by-step protocols were established for Au recovery from diverse e-waste sources, such as smartphones and smart chip cards. The study also highlighted the importance of chemical pre-concentration of e-waste to remove base metals, facilitating efficient PM recovery. Finally, a key innovation of this work is introducing a new pseudo-mix order fractional model, based on the preference of active sites with fractional assumptions, which more accurately correlates the complex sorption kinetics observed in complex systems.

Controllable H2S supply via membrane contactors for safe and efficient arsenic precipitation from acidic wastewater

Sulfide precipitation is a popular technique for the treatment and resource recovery of arsenic-containing dirty acid wastewater. However, this approach frequently suffers from toxic hydrogen sulfide (H2S) escape and agent wastage issues. Herein, a safe and efficient technique is proposed based on a polytetrafluoroethylene membrane contactor wherein the mass transfer resistance of the gas, membrane, and liquid phases can be easily and independently regulated to control the H2S supply. Additionally, H2S is transferred in bubble-free form, fundamentally avoiding the issue of gas escape, and uniform membrane distribution contributes to evenly distributed H2S delivery. The results demonstrated that 99.3% arsenic precipitation could be achieved and the H2S emission ratio was limited to <0.12%, which was significantly better than traditional methods. Thus, highly efficient separation and resource recovery of heavy metals in wastewater can be achieved using this unique and controllable low-dose H2S supply method. The separation factor between copper and arsenic was as high as 7490.9. This study provides a safe, reliable, and promising new approach for the treatment of arsenic-containing acidic wastewater.

Adaptive vertical Plug-flow transition metal catalyzed Bioelectric membrane reactor for enhancing the efficient treatment of rare earth wastewater

The presence of rare earth elements (REEs) has a certain inhibitory effect on microorganisms, making the biological treatment of REEs wastewater an area of ongoing research and exploration. In this study, a vertical architecture anaerobic process and transition metal catalyzed bioelectromembrane reactor (IVABEMR) were integrated to continuously treat REEs, enhancing the potential for efficient treatment and recovery analysis. The IVABEMR demonstrated exceptional performance in removing La(III), Ce(III), Y(III), Eu(III) and Tb(III), the highest removal efficiency can reach 99.9%, 99.8%, 99.9%, 99.9%, 100%. Removal efficiency was enhanced by an electroactive electrode membrane driven by autogenous bioelectricity. Feature analysis revealed that self-released electroflocculated nucleus, recycling electromembrane reduction, and activated sludge had significant impacts on the decontamination outcomes of REEs. Functional microorganisms including Proteobacteria, Bacteroidetes, Firmicutes at phylum level survived at high abundance in the process, establishing an adaptive and stable relationship. This study provides technological optimization for efficient biological treatment, has the advantages of environmental protection and economy, and provides a feasible idea for the treatment of REEs wastewater.

Efficient β-carotene recovery from surfactant-based aqueous solutions: Advancing from experimental to process simulation

β-carotene is a carotenoid present in the human diet with numerous functions in the body. This work suggests a new platform for efficiently recovering this bioactive compound from aqueous solutions. For the first time, a ternary deep eutectic solvent (DES) is proposed to promote phase separation in aqueous solutions of non-ionic surfactants (Triton X-102 and Tween 20). The influence of temperature on the miscibility regions was investigated from 298.15 K to 308.15 K as a preliminary step. The obtained phase diagrams at three temperatures were accurately correlated using four empirical equations. The extraction capacity of these novel combinations was analysed by means of the Tie-Lines (TL) and their derived magnitudes: Tie-Line Length (TLL) and Slope (S). The reliability of the TLs was ascertained through three empirical equations. Analysis of the data showed that more than 99 % of the model carotene could be extracted using ChCl:U:Gly from a Triton X-102 aqueous solution at 308.15 K. Process simulation using SuperPro Designer confirmed that an effective and sustainable process for recovering β-carotene from algal biomass can be designed using a simple approach.

Data-Analytics-Driven Sectorization Review Enables Efficient Reservoir Management

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 216359, “Data-Analytics-Driven Subsurface Reservoir Sectorization Review of a Giant Abu Dhabi Onshore Field Carbonate Reservoir for Efficient Reservoir Management,” by Khalid Javid, Sara Alshkeili, and Fatema Al-Hammadi, ADNOC, et al. The paper has not been peer reviewed. _ The complete paper discusses an approach used to sectorize a mature onshore Abu Dhabi giant carbonate reservoir for the purposes of reservoir management, offtake, and injection balancing. The reservoir is developed under a line-drive water-alternating-gas (WAG) scheme in combination with peripheral water injection. The development plan for the reservoir includes massive deployment of maximum reservoir contact (MRC) horizontal wells and a gas-based enhanced oil recovery scheme. A practical data-driven approach, based on one of the operator’s integrated reservoir management (IRM) workflows, was selected for the purpose of sectorization. Field Development Background Reservoir A is part of a giant oil field considered low permeability. Its porosity ranges between 13 and 26%, while permeability increases from 1 md on the flanks to 50 md in the crest of the structure. Production began 30 years ago, and the development scheme has undergone several transformations since. Currently, it is being developed under mid-flank line-drive waterflooding combined with crestal WAG and peripheral water injection. The current recovery factor of Reservoir A is approximately 10%. Two field-trial pilots were implemented (gas-injection and water-injection pilots) and then were converted to WAG injection between 2007 and 2013. These locations show high gas/oil ratio (GOR) and high water cut (WC). The development scheme includes downspacing of the existing line-drive to approximately 300 m intended to enhance sweep efficiency and increase recovery factor. The number of wells is expected to increase substantially. To optimize well placement and reduce development capital expenditure and subsurface congestion with other development targets in the field, development will capitalize on long horizontal MRC wells. Reservoir Sectorization Objectives. The sectorization exercise undertaken for Reservoir A aimed to achieve the following: - Establish a manageable number of sectors and allow creation of relevant, meaningful reservoir management key performance indicators and more-efficient surveillance programs - Honor main geological features -Reflect reservoir pressure distribution and communication between different areas of the reservoir - Reflect fluid-front movement - Reflect well-performance trends - Honor future development plans (including MRC wells) Proposed Sectorization Options. Reservoir A originally was divided into 13 regions for reservoir management, surveillance, and reservoir monitoring planning purposes, including production and injection balancing, voidage replacement ratio (VRR), pressure performance, and diagnostic plots. At the start of the study, eight sectorization scenarios were proposed. These scenarios were evaluated following a methodology described in the complete paper, aiming to combine the initial 13 regions into a smaller number of sectors where possible. Each scenario was evaluated against criteria including data analytics; the scheme honoring most of the criteria with an optimal number of sectors would be selected.

Effects of short-term nitrogen addition on the recovery of alpine grassland in the Tianshan Mountains of Xinjiang, China.

The restoration of alpine grasslands has garnered significant attention across various sectors. Historically, natural restoration has been the primary approach for grassland recovery, characterized by its prolonged duration. To expedite the recovery of degraded grasslands, it is essential to identify the limiting factors of restoration, enabling efficient and rapid recovery. Appropriate nitrogen (N) addition levels have been considered a potential strategy to enhance the recovery of grassland ecosystems and augment their ecological benefits. However, the effectiveness of N addition in alpine grassland restoration remains debated. This study investigated the impact of five N addition levels (CK: control [0 g/m2]; LN: low N [5 g/m2]; MN: medium N [10 g/m2]; HN: high N [15 g/m2]; SN: severe N [20 g/m2]) and two experimental approaches (N addition once per year [NPY] and three times per year [NTY] at the same dosages) on plant and soil properties and the maximum restoration capacity of alpine meadows. Our findings reveal three key insights: The level of N addition was the primary factor influencing aboveground plant biomass and coverage. Plant diversity decreased under the NTY regime and increased with NPY in the Bayinbruck grassland. N addition significantly altered soil properties, including pH, salinity, soil organic carbon (SOC), soil-available phosphorus (AP), and soil total phosphorus (TP). Notably, soil TP, total nitrogen (TN), and AP substantially impacted plant community structure and diversity. Based on structural equation model (SEM) and analysis of variance (ANOVA), optimal grassland restoration was achieved with the HN (15 g/m2) treatment under NPY and the MN and HN (10 and 15 g/m2) treatments under NTY. Overall, our study offers crucial insights into the conservation, management, and restoration of grassland ecosystems on the Bayinbruck Plateau. It underscores the significance of N addition effects on plant communities, vegetation restoration, and soil properties.

Isolation and Structural Characterization of Natural Deep Eutectic Solvent Lignin from Brewer's Spent Grains.

Brewer's spent grains (BSG) offer valuable opportunities for valorization beyond its conventional use as animal feed. Among its components, lignin-a natural polymer with inherent antioxidant properties-holds significant industrial potential. This work investigates the use of microwave-assisted extraction combined with acidic natural deep eutectic solvents (NaDESs) for efficient lignin recovery, evaluating three different NaDES formulations. The results indicate that choline chloride-lactic acid (ChCl-LA), a NaDES with superior thermal stability as confirmed via thermogravimetric analysis (TGA), is an ideal solvent for lignin extraction at 150 °C and 15 min, achieving a balance of high yield and quality. ChCl-LA also demonstrated good solubility and cell disruption capabilities, while microwaves significantly reduced processing time and severity. Under optimal conditions, i.e., 150 °C, 15 min, in the presence of ChCl-LA NaDES, the extracted lignin achieved a purity of up to 79% and demonstrated an IC50 (inhibitory concentration 50%) of approximately 0.022 mg/L, indicating a relatively strong antioxidant activity. Fourier transform infrared (FTIR) and 2D-HSQC NMR (heteronuclear single quantum coherence nuclear magnetic resonance) spectroscopy confirmed the successful isolation and preservation of its structural integrity. This study highlights the potential of BSG as a valuable lignocellulosic resource and underscores the effectiveness of acidic NaDESs combined with microwave extraction for lignin recovery.

Integrating Petrophysical, Hydrofracture, and Historical Production Data with Self-Attention-Based Deep Learning for Shale Oil Production Prediction

Summary As the energy industry increasingly turns to unconventional shale reservoirs to meet global demands, the development of advanced predictive models for shale oil production has become imperative. The inherent complexity of shale formations, coupled with the intricacies of hydraulic fracturing, poses significant challenges to efficient resource extraction. Our study leverages a substantial data set from the Ordos Basin to develop an advanced predictive model, integrating 18 parameters that blend static petrophysical attributes and dynamic factors, including hydraulic fracturing parameters and real-time pump pressure data. This holistic approach enables our self-attention (SA) model to accurately forecast future production rates by processing the complex interplay between reservoir characteristics and operational inputs. In testing across three wells, the model achieved average accuracies of 99.28% for daily oil production (DOP) and 99.25% for daily liquid production (DLP) over 20 days, surpassing traditional long short-term memory (LSTM) and gated recurrent unit (GRU) models, proving its efficacy in fractured well production forecasting. Furthermore, using the initial 30 days of production data as input, the model demonstrated its capability to predict DOP and DLP over a one-year period, achieving prediction accuracies of 96.2% for DOP and 99.6% for DLP rates. Our model’s profound implications for the shale industry include establishing a quantifiable link between key factors and production forecasts, guiding the optimization of controllable aspects, and serving as a decision-support tool for more efficient and cost-effective oil recovery.

Ammonia recovery from real biogas slurry in the up-scaled Donnan Dialysis-Osmotic Distillation membrane-based system: Performance and potentials

Recovering ammonia from wastewater is crucial for building a circular economy and achieving carbon neutrality. Some innovative ammonia recovery technologies have shown great potential yet lacking theoretical guidance for up-scaling from laboratory to practical applications. Based on our previously-proposed Donnan dialysis-osmotic distillation (DD-OD) hybrid process for selective ammonia recovery at nearly zero energy input, two challenges as modelling/prediction and product application were solved in this study. Under the guide of the tailor-made mass transfer model, a reasonable design of the reactor and operating parameters was fixed, whose performance in recovering ammonia from real biogas slurry and the feasibility of the recovered product as irrigation water was then investigated. The up-scaled DD-OD reactor achieved efficient and stable ammonia removal and recovery (∼75 % and ∼ 65 %, respectively) and excellent impurity retention efficiency (∼95 %) in 360 h continuous run. Impurities deposited on the cation-exchange membrane did not affect ammonium transfer and were effectively removed by water washing, and no fouling was found for the hydrophobic membrane, highlighting its long-term capability for ammonia recovery. Moreover, the cost-effectiveness of the process was analyzed, which could be greatly improved given the future improved membrane materials. A proper dilution of the recovered product for irrigating cabbage and radish promoted plant growth, recycled product containing a moderate ammonia concentration (136 mg/L) was highlighted and well-rounded, multi-element nutrient profile was recommended. The above results provide theoretical guidance for the scaling-up of ammonia recovery module and a reference basis for the application of recycled products in agricultural irrigation.

High-performance polyurea nanofiltration membrane for waste lithium-ion batteries recycling: Leveraging synergistic control of bulk and interfacial monomer diffusion

The development of high-performance nanofiltration (NF) membranes with extreme chemical stability is urgently needed for the recovery of spent lithium. In this study, a series of polyurea membranes with high lithium recovery efficiency and pH stability were fabricated by zone-regulated interfacial polymerization (IP). The reaction inhibitor Cu2+ in the bulk aqueous phase reduces IP intensity by reversibly binding to the amino groups of polyethyleneimine monomers through chelate bonds. Meanwhile, surfactant promote the uniform diffusion of macromolecular aqueous monomers at the phase interface. The milder polymerization reaction and the more stable phase interface endow the polyurea membrane (NF10k PEI-SDS-Cu2+) with higher water permeance (2.1 L m-2 h-1 bar-1), desirable MgCl2 rejection (94.7%), and excellent fabrication repeatability. Moreover, the membrane demonstrates stable separation selectivity for Co2+/Li+ and SO42-/Li+ under conditions of 0.05 mol L-1 H2SO4 and 2 mol L-1 LiOH, respectively. Our study provides a facile method for constructing NF membranes with extreme pH stability and confirms the feasibility of membrane-based lithium recovery.

Synchronous conversion and targeted separation of valuable metals from spent hydroprocessing catalysts

Sustainable recovery of spent hydroprocessing catalysts (sHPC) is crucial to address environmental and resources issues. However, the existing recycling methods recover limited metal components due to uncontrollable phase transition and complicated separation procedures, leading to poor utilization efficiency of the sHPC. Herein, a synchronous conversion and targeted separation strategy was designed to achieve full-component recovery of the sHPC. The insoluble phases of Al/Ni/Mo/V could be completely transformed into soluble sulfate via sulfation roasting at 400 °C. The roasted sulfate products can be directly leached by water with efficiencies close to 100%. Targeted separation of the multi-ions could be achieved based on their species difference in the leachates. Anionic HV10O285− and HMoO4− species were co-extracted by basic trioctylamine extractant, while cationic Ni2+ and Al3+ were extracted by acidic HBL110 and P204, respectively. Benefiting from the sulfation roasting and selective extraction procedures, the recovery efficiencies of Al, Ni, Mo, and V elements achieved 97.2%, 95.8%, 94.1%, and 94.3%, respectively. The explored synchronous conversion and targeted separation strategy is an industrial-feasible candidate for sustainable utilization of the retired catalysts.

Natural refrigerant matching optimization and characteristic analysis of two-stage Rankine cycle for LNG cold power generation process

Unlike most waste heat recovery, LNG is a multi-component mixture, low temperature and wide boiling range make it difficult to achieve efficient recovery of cold energy with a conventional single-stage Rankine cycle. On the other hand, with the stricter restrictions on hydrofluorocarbons under the Kigali Amendment, more environmentally friendly natural refrigerants deserve more attention as alternatives. Therefore, to improve the recovery efficiency of cold energy, this paper studied the optimal natural refrigerant combination of two-stage Rankine cycle LNG cold energy power generation system, and analyzed the performance characteristics and influencing factors of the system. In addition, in order to verify the application potential of the system, the levelized cost of electricity and payback period of the system for different refrigerant combinations were also analyzed. The results show that at a delivery pressure of 0.6 MPa, the refrigerant combination of ‘ethylene + propane’ has the best power generation performance, with a net generation and exergy efficiency of 9020.8 kW and 35.54 %, respectively. The refrigerant combination of ‘ethylene + propylene’ has the best economic performance, with a levelized power cost and payback period of 0.0355 USD/kWh and 2.76 years, respectively. In the case of high delivery pressure requirements, ‘ethane + propane’ becomes the optimal refrigerant combination, which can simultaneously achieve optimal power generation performance and economic performance. In addition, as the delivery pressure decreases, the power generation and economic performance of the system will improve. It is also found that among all refrigerants, ethane and ethylene have the highest evaporation pressure, which is conducive to obtaining a greater effective enthalpy drop, but the required superheat is also larger, which reduces the heat transfer efficiency of the evaporator to a certain extent.

Pore-scale study of three-dimensional three-phase dynamic behaviors and displacement processes in porous media

Carbon dioxide geological sequestration is a key method to alleviate global warming and enhance oil recovery, where the three-phase displacement processes of oil, water, and carbon dioxide gas in porous media are frequently encountered. In this study, a three-phase three-dimensional lattice Boltzmann method coupled with special wettability and outlet boundary schemes is adopted to simulate the three-phase displacement processes in porous media. The method is validated by the contact angles on a curved surface and droplet flowing through the outlet boundary. With this method, the influences of capillary number, wettability, and local large pores on three-phase flow are investigated. In particular, different dynamic behaviors of fluids are observed at the pore scale, such as bypass-double displacement, stop-wait displacement, burst displacement, snap-off trapping, and corner flow. Further, Euler number and oil saturation are calculated to quantitatively characterize the fluidic morphology and displacement efficiency under different conditions. For all three phases, the Euler number of low capillary number, strong water-wet, and structures with large and medium pores is relatively low, indicating that the morphology of fluids is more connective. For enhancing oil recovery efficiency, high capillary number and strong water-wet structures are beneficial.

Study of Heavy Oil In-situ Combustion with Copper Biocatalysts: Kinetics and Thermodynamic Aspects of High-Temperature Oxidation Reactions

In-situ combustion is considered an efficient thermally enhanced oil recovery method. However, the combustion front stabilization remains a challenge for the scientific community. The present study examines the efficacy of copper tall oil (Cu-TO) and copper sunflower oil (Cu-SFO) on heavy oil high-temperature oxidation reactions, which are believed to solve this challenge. We applied non-isothermal differential scanning calorimetry (DSC) analyses combined with an isoconversional kinetic approach in order to calculate kinetic parameters, thermodynamic functions, and the effective rate constant of these reactions. The obtained results demonstrated that both catalysts are able to reduce the activation energies and shift oxidation regions to lower temperatures, with Cu-SFO showing superior performance. Kinetic predictions further supported these findings and revealed that the selected catalysts contributed significantly to decreasing oxidation times across all conversion ranges. Additionally, thermodynamic analyses indicated that Cu-SFO facilitated a more ordered and energetically favorable oxidation process, as demonstrated by increasingly negative entropy values and consistently lower Gibbs free energy. The research highlights the Cu-SFO catalyst exceptional ability to accelerate the transition from low-temperature to high-temperature oxidation while maintaining high catalytic activity. Taken together all these results, this research work contributes to provide comprehensive insights from the kinetic and thermodynamic analysis that reveal unique catalytic effects and reaction mechanisms, presenting an approach to stabilize combustion front and improve heavy oil recovery efficiency, addressing a critical challenge in the field of in-situ combustion.

Numerical study of vehicle motion during water exit under combined lifting force and wave action

During the retrieval process of the deep-sea mining vehicle (DSMV), the stability of the retrieval system is strongly influenced by the interaction between the vehicle body and the surrounding seawater due to the vehicle's complex shape and wave motion. Naturally, the negative side effects of significant changes in the vehicle's attitude and the water exit position can only increase retrieval's challenge. To investigate the characteristic of the flow field of the DSMV, this study employs the computational fluid dynamics method based on the Reynolds-averaged Navier–Stokes equations integrating the volume-of-fluid multiphase flow model with a fifth-order Stokes-wave model to explore the attitude and displacement changes of the vehicle during the water exit process in the ocean wave environment. The results indicate that the wave phase and lifting force are the major effect factors in the DSMV's water exit process. An appropriate lifting force under a specific wave phase can effectively reduce attitude changes and positional drift of the DSMV during water exit, thereby enhancing recovery efficiency and stability.

A deep treatment process for chemical polishing wastewater towards resource recovery: Optimization and performance

The chemical polishing industry generates abundant wastewater that contains high concentrations of phosphoric acid and metal ions. In light of the rapid growth of the economy and the stringent demands for sustainability, developing cost-effective and energy-efficient technologies for wastewater treatment is crucial. Herein, an EPRC-ICT-ANT process integrating electrodialysis, iron contact, and alkali neutralization, was proposed to deeply treat chemical polishing wastewater and achieve optimal recovery of acid, phosphorus, and aluminum. The results indicated that with the electrochemical phosphoric acid recovery cell (EPRC), the maximum recovery efficiency and final phosphoric acid concentration were 34.6 % and 25.2 g/L. Following the iron contact tank and alkali neutralization tank (ICT-ANT) treatment, a remarkable 99.17 % removal of Al3+ and 49.5 kg/t wastewater yield of AlPO4 were achieved. Simultaneously, the released Fe2+ and remaining PO43- triggered the rapid formation of vivianite with a yield of 120.7 kg/t wastewater. This comprehensive treatment strategy led to the near-complete removal of Al3+ and PO43- (∼100 %) with an impressive recovery of Al3+ (∼100 %) and PO43- (75.7 %), emphasizing its immense potential for chemical polishing wastewater treatment.

Simulation of a System to Simultaneously Recover CO2 and Sweet Carbon-Neutral Natural Gas from Wet Natural Gas: A Delve into Process Inputs and Units Performances

The growing need for carbon-neutral energy solutions necessitates the development of efficient systems for carbon dioxide (CO2) recovery and the production of sweet carbon-neutral natural gas (CNNG) from wet natural gas. Despite existing approaches, limitations in process optimization, solvent efficiency, and output purity persist. This study aims to address these gaps by simulating a system for simultaneous recovery of CO2 and CNNG using an integrated three-stage process, modeled in Aspen Plus V8.8. The unique aspect of this work lies in employing the ENRTL-RK base model, coupled with sensitivity analyses to optimize input parameters across 13 interconnected process units, including compressors, heat exchangers, and extraction columns. Key innovations include the novel configuration of units, yielding a recovery efficiency of 95.94% for CNNG and a CO2 purity of 93.185% at optimal conditions, surpassing conventional methods. The performance of the monoethanolamine (MEA) solvent was enhanced by careful adjustment of input parameters, improving its absorption efficiency by 12% compared to standard operational settings. Sensitivity analysis revealed critical parameters such as feed pressure and solvent flow rate as primary drivers for maximizing output efficiency. This study also provides a detailed quantitative assessment of power requirements, with a compressor brake horsepower (BHP) of 18,2605 watts at 110 bar discharge pressure. It addresses the existing research gap by introducing a systematic approach to process optimization, significantly improving the purity and recovery of CNNG and CO2 while minimizing energy consumption. The results not only demonstrate the viability of this process but also provide a foundation for further refinement in sustainable gas processing technologies.