Chemical Engineering and Processing - Process Intensification最新文献

In recent years, the demand for phosphoric acid, a key raw material for lithium iron phosphate batteries, has surged. However, current phosphoric acid extraction equipment faces challenges such as low mass transfer efficiency and difficulty in phase separation, leading to reduced production efficiency, bulky equipment, and scaling issues. To address these problems, this study introduces a T-type central plug-in microreactor (TCPM) designed to enhance mass transfer efficiency and facilitate rapid phase separation. The extraction of phosphoric acid from the water phase to the organic phase (volume ratio of tributyl phosphate to kerosene is 4:1) was chosen as the experimental system. We investigated the effects of various parameters on liquid-liquid flow and mass transfer characteristics in the TCPM. Visualization techniques identified slug and parallel flow as the primary liquid-liquid flow patterns within the TCPM. Notably, the central plug-in promotes the formation of parallel flow, improving phase separation compared to conventional T-type microreactors. The volume mass transfer coefficient of the TCPM ranges from 0.023 to 0.074 s^-1, and the optimal phosphoric acid extraction efficiency and volume mass transfer coefficient can reach up to 90.5% and 0.074 s^-1, respectively, outperforming conventional T-type microreactors. Predictive model for extraction efficiency was developed, showing deviations within 10%. These findings demonstrate the TCPM's potential as an efficient phosphoric acid extraction device with rapid phase separation, holding significant promise for liquid-liquid extraction applications.

Wave-rotor-based gas pressure dividing (GPD) is a potential technology that can synchronously conduct gas compression and expansion. This study, proposes a novel curving flow channel of wave rotor (C-FCWR) for the three-port GPD device, aiming to settle the technical problem of traditional width-constant straight flow channels (WS-FCWR). A series of comparative hydrodynamics and thermodynamic analyses are conducted. For the optimized C-FCWR with a forward-curving angle of +10°, the flow vortex generation in the medium-pressure (MP) and low-pressure (LP) ports is rather limited, the shaft power is as low as -0.45 kW, the shock wave efficiency is beyond 99.8 %, and the expansion depth remains above 26.4 K, proving a great technical advantage. For the application feasibility of the optimized C-FCWR to working conditions, a compression ratio below 1.2 and an expansion ratio of 1.8 are conducive to the overall performance of the GPD device.

Energy and environmental issues are today's major concerns. To solve huge energy needs, the increasing use of fossil fuels leads to significant amounts of CO₂ emissions, which have major negative effects on the environment. An urgent reduction in CO₂ emissions is therefore an absolute priority to minimize the actual global warming. Carbon capture & utilization (CCU) has been introduced as a sustainable avenue. Viewing CO₂ as a resource (renewable feedstock) rather than a waste, its conversion into different value-added products offers an attractive and efficient alternative to CO₂ storage via chemical recycling. However, CO₂ is a very stable molecule whose conversion is a very difficult and complex task. On the other hand, from a sustainable development perspective, CO₂ conversion by catalytic hydrogenation reactions requires hydrogen derived from renewable sources. Because of numerous benefits, our group has been focussing high attention to the application of different process intensification tools to proposed technologies for CO₂ capture in gas/liquid contactors (including membrane separation and enzymatic processes), highly pure hydrogen production with in-situ CO₂ capture, and CO₂ conversion by catalytic hydrogenation, which will be reviewed in the present paper.

The assessment of the sulfate radical-based AOPs (SR-AOPs) in an immobilized reactor combined with various methods for treating brilliant blue FCF (BBF) is presented with emphasis given to energy efficiency, sustainable development, and practicality. The SR-AOPs method, used at the pilot scale under UV light irradiation has a treatment capacity of 0.519 m³/l. It is optimized utilizing the central composite design (CCD) approach for UVA-PS-TiO₂ process treatment, an empirical connection concerning removal efficiency was established by choosing as factors TiO₂ concentration [0.5–2] g/l, the treatment time [30–180] min, and the concentration of S₂O₈ [1–3] g/l. The model's significance for the maximal BBF elimination was determined using the variance results (ANOVA) and the adequacy result of Canonical and ridge analysis was also conducted to determine optimal result. In terms of kinetics 3.89 h⁻¹ for NF, 2.61 h⁻¹ for UVA-PS-TiO₂/NF, and 0.68 h⁻¹ for UVA-PS-TiO₂ and economic evaluation PS-TiO₂ with a total cost of 572,32 €/m³ and PS-TiO₂NF with an operation cost of 574,28 €/m³. The integration of membrane processes (NF) with UV/ PS/TiO₂ allow to reduce the total cost of process and to enhance the kinetic parameters. The technical-economic study demonstrated a successful scenario with a 23-year payback period.

The surplus of crude glycerol from biodiesel production can be valorized by the glycerolysis of various feedstocks such as triglycerides, free fatty acids, and fatty acid methyl esters to higher-value monoglycerides (MGs) and diglycerides (DGs). These products are widely used in the food and pharmaceutical industries as emulsifying, stabilizing, and nutritional agents. High purity of MGs and DGs production necessitates high energy consumption to maintain a high reaction temperature and to operate a high vacuum or molecular distillation. This perspective discusses various potential feedstocks that involve different reaction routes and by-products, the effects of operating parameters on glycerol conversion, MGs and DGs selectivities, and various intensified reactors to enhance the reaction performance. In addition, key challenges and perspectives for the success of glycerol valorization for MGs and DGs are highlighted.

A two-stage microreactor with intensely swirling flows (MRISF-2) allows to perform effectively two subsequent reactions in synthesis of nanosized particles. Micromixing quality plays crucial role in ultrafast co-precipitation reactions, and depends both on the specific energy dissipation rate and on the geometry of the reactor as well as the solutions feeding manner. Solutions in MRISF-2 could be supplied by different ways: through the upper and/or lower tangential inlet pipes and through the central (axial) inlet pipe. This paper is aimed to compare experimentally and numerically three ways of liquid solutions feeding in MRISF-2 with objective to find the conditions of the highest specific energy dissipation rate. The best method of solutions supplying was found experimentally and confirmed numerically: one solution is supplied tangentially, the other through the central inlet pipe. The average specific energy dissipation rate for this method is 1.7 and 6.0 times higher compared to supply through two upper tangential inlet pipes and upper + lower tangential inlet pipes, respectively. This advantage was confirmed by measurements of segregation index Xs by use of iodide-iodate reaction technique. Good agreement between experimental and numerical simulation results for energy dissipation rate was found for all studied cases.

Natural rectorite modified by the hydrothermal method was employed to prepare a catalyst for the slurry-phase hydrocracking of vacuum residue (VR). The influence of hydrothermal treatment on the properties of rectorite and the performance of the corresponding catalyst was examined. Hydrothermal treatment of the rectorite led to the formation of Fe₃O₄, as evidenced by H₂-TPR analysis. XPS results indicate that the hydrothermal treatment of rectorite can intensify the sulfidation process of Mo species supported on it, possibly due to modifications in the surface properties of the rectorite. Comparative slurry-phase hydrocracking tests showed that the catalyst supported on hydrothermally treated rectorite exhibited significantly higher VR conversion, higher liquid product yield, and higher yields of gasoline and diesel fractions, but lower gas yield compared to the catalyst supported on untreated rectorite. This is ascribed to the high hydrogenation activity of the catalyst supported on hydrothermally treated rectorite, which effectively suppresses the over-cracking reactions of intermediate products that would otherwise produce gas, illustrating the process intensification achieved through hydrothermal treatment.

In this study, PFC system is investigated to improve the concentration and yield of lysozyme. The research focused on an attempt to thoroughly construct an ice crystallizer with measurable and optimized design parameters for an efficient lysozyme protein concentration procedure because the productivity of PFC is always an issue. A new Multiple Probe Cryo-Concentrator (MPCC) device was designed and successfully equipped with probes having a well-distributed cooled surface area for ice crystallization with proper internal cooling temperature control as well as a solution movement mechanism provided by a stirrer in the tank. The impact of different operating parameters is optimally investigated. Central Composite Design (CCD) is utilized to optimize PFC operating conditions and their response to partition constant (K-value) and solute yield. The results showed that a coolant temperature of -12 ⁰C, stirrer speed of 350 rpm, operation time of 40 min and initial concentration of 10 mg/mL gave the best K-value (0.132) and solute concentration yield (87.39 %). The design elements of the equipment are crucial in providing improved PFC performance. The study revealed that the PFC system designed and applied in this study can improve the lysozyme protein concentration as needed in the food and pharmaceutical industry.

The sulfurous compounds in natural gas liquids should be reduced to the extent of satisfying the standard recipes due to corrosion, poisoning of catalysts in downstream processes, reduction in the quality of hydrocarbon products and environmental issues. Ultrasound-assisted oxidative desulfurization is an emerging method for sulfur removal from natural gas liquids. Since natural gas liquids exist in the liquid form of hydrocarbons at high pressures and ambient temperature (25 °C), this work aims to investigate the optimal conditions governing ultrasound-assisted oxidative desulfurization for various sulfurous compounds including mercaptan, sulfide and thiophene at high pressure and finally to appraise the adsorption of oxidized sulfurs and the regeneration of the adsorbent using elution with hot water. So, the effects of sulfur content and ultrasonication time were evaluated at 30 bar. Results showed that as the initial sulfur concentration in normal heptane was increased from 0.00 to 3000 ppmS, the sulfur removal efficiency was enhanced by less than 2 % of 95.9 % and of course, the increased ultrasonication time improved the sulfur removal efficiency. Next, results of the sulfone adsorption using zeolite-13X at 30 bar in continuous mode confirmed that the breakthrough time was reduced from 63 to 12 min as the weight hourly space velocity was increased from 5 to 20 h⁻¹ and pursuantly, the mass transfer zone diminished. Besides, the breakthrough time decreased by 45 - 10 min for increasing the initial sulfur content from 200 to 1000 ppmS. Changing the pressure of the adsorption process from 1 to 30 bar caused the improvement of sulfone adsorption capacity by approximately 3.75 times. In continued, the regeneration of zeolite-13X contaminated with sulfone by flowing hot water was evaluated and the zeolite-13X bed was completely regenerated.

Driven by the goal of carbon neutrality, the new development pattern of the refining and chemical industry has changed from distillate processing to component processing. A key difficulty in precise separation of oil and gas is a low separation efficiency, which could be attributed to poor gas-liquid mass transfer efficiency and poor match between selectivity and solubility. While in the oriented conversion of oil, low yield of the target product and short catalyst life are key constraints, since complex parallel sequence reactions in conversion process is difficult to control. Therefore, our research group has focused on the main line of "precise separation and oriented conversion of oil and gas", to cope with a key chemical common problems of "mass transfer and reaction" in the process of "separation and conversion" of C3-C20 hydrocarbon components, we solved two scientific problems of "intermolecular force" in separation process and "structure-activity relationship of catalytic materials" in conversion process. It has realized the goal of "quality upgrade, product transformation and optimal utilization" mainly for production of high-quality fuel and chemical feedstocks. And it has contributed to form a new pattern of refining and chemical integration of "high-qualified oil and gas as well as high-value chemicals".