Preparation of high purity squalene from soybean oil deodorizer distillate with the combination of macroporous resin and thin-film evaporation coupling distillation

ABSTRACT

In this study, the combination of macroporous adsorbent resins (MARs) and thin-film evaporation coupling distillation (TFECD) was studied systematically, with aim to obtain high value-added squalene from soybean oil deodorizer distillate (SODD). Five types of resins (X-5, D-101, D4020, DM301, and AB-8) were first used to evaluate the adsorption/desorption properties of squalene. D101 resin exhibited higher adsorption/desorption capacities and desorption ratios for squalene based on static adsorption results among the tested resins. We further investigated the adsorption kinetics, isotherms, and thermodynamics with D101 resin as adsorbent. The adsorption of squalene on D101 was best fitted to pseudo-second-order kinetic model and the Langmuir equation. The dynamic adsorption and desorption indicated that similar results were observed in the static adsorption test. The purity of squalene was increased from 7.5 to 82.5% with the recovery up to 88.5% after separation on D101 column. The resin-refined sample was directly subjected to TFECD purification. Under optimized process parameters, the final product with purity of 98.5% and recovery yield of 76.5% was confirmed by high-performance liquid chromatography (HPLC) analysis. The present study provided an effective method for large-scale production of high purity squalene.     

The dependence of evaporation and crystallization kinetics on dynamic and thermal background

In technical problems there is often the need to simultaneously describe both non-stationary evaporation and non-stationary crystallization of droplets and films. Poor wettability of the wall and high heat fluxes lead to the film rupture and the formation of pools, dry spots, droplets. To date, there are no well-developed methods for calculating crystallization and evaporation in the presence of the factors. Evaporation and crystallization of a drop are shown to fundamentally differ from those of a thin layer. The rate of evaporation prior to crystallization controls the crystallization kinetics. The evaporation and crystallization rates for the film (under identical conditions) are significantly higher than for the drop. The difference in the thickness of the diffusion and dynamic boundary layers affects the evaporation rate of an aquatic salt solution. For correct simulation of evaporation, it is necessary to take into account the thicknesses of the thermal, diffusion and concentration boundary layers.     

Development of a continuous evaporation system for an API solution stream prior to crystallization

A bubble column was investigated as a method to achieve a desired and controllable rate of evaporation of a pharmaceutical solution. Applying a thermodynamic model to predict the rate of evaporation, all predicted values were observed to have accuracies within the bounds of instrumentation errors (<5% absolute). The developed model accounted for the measured effect of reduced vapor pressure, caused by the dissolved solids as a function of their concentration. A general method to obtain accurate measurement of this effect is introduced and applied, improving the accuracy of model predictions. Consistent and repeatable evaporation rates ranging from 0.7 to 6.9 g/min were achieved experimentally, and errors between predicted rates and observed ranged from 0.219% to 4.19% absolute. This demonstrates a controllable and flexible method for the evaporation of process streams which can be compared to harsher conventional methods such as boiling. The column was configured in a continuous mode and coupled to a downstream crystallizer (MSMPR). Using the column as a controllable concentrator, the concentration of a dilute feed stream of paracetamol in methanol was increased in a single equilibrium stage. The column demonstrated the ability to concentrate the solution in flow by 179%, delivering a flow of 2 ml/min of concentrated liquor to the MSMPR. The MSMPR achieved steady-state of control, measured by offline dissolved concentration analysis and particle count by FBRM in situ, highlighting the applicablity of the column to perform reliably in a continuous tandem.     

Interfacial photothermal water evaporator based on nanoporous microwave-expanded graphite and coconut waste fibers@recycled polystyrene as substrate

Solar water evaporators (SWE) have shown growing interest due to their capacity to transform sunlight to thermal energy. In this work, SWE were prepared based on microwave-expanded graphite as light absorber deposited onto an ecological porous substrate obtained by casting a mixture of coconut fibers and recycled polystyrene. The materials were characterized by SEM, FTIR and UV/Vis-NIR spectroscopies, and thermogravimetric analyses. It was observed that the light absorber film presented high and wide light absorption in the solar electromagnetic spectrum and increased superficial area when compared to the unexpanded graphite film counterpart. Nanopores between 400 and 900 nm and microcavities in the 200 to 500 μm range were formed at the surface of the SWE after 6 seconds of microwave exposure, which are destroyed at higher exposure times. SWE of laboratory scale diameter were tested for water evaporation at different light intensities, microwave expanding time, and thicknesses to determine their effects on evaporation rate and efficiency. It was observed that SWE rates increased from 1.09 ± 0.006 to 1.73 ± 0.007 kg h⁻¹ m⁻² for unexpanded and expanded graphite through 6 seconds, respectively; being the latter the best SWE reaching 91.5% of efficiency at 1200 W m⁻² of illumination. This efficiency was stable after reaching the maximum stable efficiency in only 15 minutes. The scaling-up of the process was studied in a SWE of 6.1 cm in diameter using a bigger glass cell in the presence of pure water or simulated seawater (3.5% NaCl), achieving efficiencies of 89.8% and 86.1%, respectively.     

Intensifying Heat Using MOF-Isolated Graphene for Solar-Driven Seawater Desalination at 98% Solar-to-Thermal Efficiency

Photothermal materials are crucial for diverse heating applications, but it remains challenging to achieve high energy conversion efficiency due to the difficulty to concurrently improve light absorbance and suppress heat loss. Herein, a zeolitic imidazolate framework-isolated graphene (G@ZIF) nanohybrid is demonstrated that utilizes ultrathin, heat-insulating ZIF layers, and G@ZIF interfacial nanocavity to synergistically intensify light absorbance and heat localization. Under artificial sunlight illumination (≈1 kW m⁻²), the G@ZIF film attains a maximum temperature of 120 °C in an open environment with a 98% solar-to-thermal conversion efficiency. Importantly, the porous ZIF layer allows small molecules/media to enter and access the embedded hot graphene surface for targeted heat transfer in practical applications. As a proof-of-concept, the G@ZIF-based steam generator realizes 96% energy conversion from light to vapor with near-perfect desalination and water purification efficiencies (>99.9%). This design is generic and can be extended to other photothermal systems for advanced solar-thermal applications, including catalysis, water treatments, sterilization, and mechanical actuation.     

Experience on horizontal‐tube falling‐film evaporation simulation by lattice‐Boltzmann method

Complex heat and mass transfers through falling‐film or spray‐film evaporation are widely used in chemical, refrigeration, petroleum refining, desalination, and food industries. Considering that microscopic effects, like surface tension, flow, mass, and heat transfers, are interdependent phenomena, the high‐precision simulation of falling‐film evaporation through a mesoscopic method is of great importance. In the current study, the lattice‐Boltzmann method and the phase‐field model with a proper source term are used for evaporation simulation in a horizontal‐tube falling film. Here, the curvature of the tube is captured by appropriate boundary conditions. Nondimensional numbers and the geometry of the model are determined in a range of practical values. By comparing the film thickness, mass, and heat transfer with valid references in the literature, an acceptable agreement is observed, which reveals the effectiveness of this method in understanding the details and predictions. Overall, the time evolution of temperature contours and streamlines during falling‐film evaporation approves the superiority of this method in keeping details along with lower difficulty and cost compared with the classical methods.     

Vitrification of cryoelectron microscopy specimens revealed by high-speed photographic imaging

Cryoelectron microsopy is a widely used technique to observe biological material in an almost physiological, fully hydrated state. The sample is prepared for electron microsopy observation by quickly reducing its temperature to ?180 °C. The high‐speed cooling induces the formation of vitreous water, which preserves the sample conformation. However, the way vitrification occurs is still poorly understood. In order to better understand the phenomenon, we have used a stroboscopic device to visualize the interaction between the electron microscopy grid and the cryogen. By blocking the free fall of the plunger once the grid has penetrated the coolant by half its diameter, we have elucidated the way in which vitrification propagates. The findings were confirmed by numerical simulation. In addition, according to our observations, we now present an alternative way to prepare vitreous specimens. This new method, with the grid parallel to the liquid cryogen surface, decreases evaporation from the sample during its free fall towards the coolant and at the same time achieves a more uniform vitrification over the entire surface of the specimen.     

减少高压溶出机组碳酸钠结晶及处理方法

高压溶出机组碳酸钠的结晶给生产带来严重危害，了解碳酸钠成分来源并采取措施，降低其含量是必要的。     

Liquid-liquid and vapour-liquid behaviour of oleyl alcohol applied to extractive fermentation processing

Investigations into the product recovery step of the extractive ethanol fermentation through partition experiments for ethanol-water-Adol^r? 85 NF ternary systems were undertaken. Experimental liquid-liquid equilibrium data for this ternary system were compared with numerical predictions based on the UNIFAC method. The influence of salts on distribution coefficients for ethanol extraction was also examined. An improvement in extraction characteristics was observed for ternary systems with salts. Flash vaporisation was used to subsequently examine the effect of liquid-liquid ternary compositions on vapour-liquid partitioning. The UNIFAC model was found to be very useful for semi-quantitative analysis of such liquid extraction systems.