The present study investigates the measurement of the phase equilibria of ternary systems KCl–PEG6000(PEG with molecular weight 6000)–H₂O at 288.2, 298.2 and 308.2 K. All the experimental data concluding the solubility of KCl in PEG6000–H₂O mixed solvents, corresponding density, and refractive index were determined. According to the results, the phase diagrams at 288.2, 298.2, and 308.2 K are divided into the three parts of regions: unsaturated homogeneous liquid (L), one liquid and one solid KCl (L+S), one liquid and two solids KCl and PEG6000 (L+2S); the area of (L+2S) decreases with an increase of temperature, while the areas of (L) and (L+S) increase with an increase of temperature. With an increment of PEG6000 in mixed solvents, the solubilities of KCl and the density decreased; inversely, the refractive index increased at three temperatures. Comparing the diagrams of KCl–PEG1000/4000/6000–H₂O at 288.2, 298.2, and 308.2 K, the sizes of regions of (L) and (L+S) decreased and that of (L+2S) increased with the increase of the molecular weight of PEG. A modified Pitzer model and Pitzer activity coefficient model were applied to simulate the equilibrium thermodynamics of the KCl–PEG6000–H₂O system at 288.2, 298.2, and 308.2 K. Comparing the experimental data and calculated dada, the thermodynamic models can give precise results with little error.

In the present study, a novel testing system is presented for obtaining distribution characteristics of pressure field inside a low specific-speed centrifugal pump with atypical open impeller, wherein the components of the system are described in detail. At three rotational speeds, the instantaneous static pressure on the casing wall of blade tip clearance and volute wall are measured under different flow conditions. The average static pressure fields are obtained and standard deviations of the pressure are also determined. The results show that the pressure distribution characteristics on the casing wall can vary with the location observed and working condition operated, and the pressure pulsation amplitude is more severe than that on the volute wall. The pressure pulsation is always the most dominant under the shut-off condition. Due to wall roughness and blade tip clearance leakage, the static pressures at the same radius circle demonstrate unsteady characteristics. From the second to the sixth cross-section of volute, the average static pressures are nearly constant as a whole, but after the sixth cross-section, the average static pressure distributions depend on the working condition significantly.

The present study investigates the extraction of a target chemical, 4-cyanobiphenyl, from model product solutions of a flow Suzuki–Miyaura coupling reaction. Fast flow extraction from an ethanol aqueous solution of 4-cyanobiphenyl was conducted using supercritical carbon dioxide as the extraction solvent under conditions of 40–60°C and 10–20 MPa. More than 80% of the 4-cyanobiphenyl was recovered in the CO₂-rich phase, and the rate was greater than 5.0 g-4-cyanobiphenyl/h for the extraction at 60°C and 20 MPa from the model solution containing salts. The effects of the ethanol mole fraction and the extraction pressure were also investigated to elucidate the effect of changes in the solvent properties on the partitioning behavior. The 4-cyanobiphenyl partition coefficient decreased with increasing ethanol mole fraction and increased with increasing extraction pressure. A model that includes the effects of changes in solubility with increasing CO₂ density and ethanol mole fraction in the water- and CO₂-rich phases was developed. The model well represents the tendency of the partitioning behavior, which indicates that the CO₂ density and ethanol mole fraction in each phase are important factors governing the partitioning behavior.

A mass exchange network (MEN), which consists of one or more mass exchangers, is a useful tool to realize pollution prevention in process industries. When a staged column is employed as a mass exchanger to synthesize a MEN, the number of trays must be rounded up to the next largest integer after obtaining an optimal design, which increases the capital cost. While designing a chemical process plant, when the capital cost increases, the operating cost should decrease. However, the operating cost was considered to be a fixed value in previous research even if the capital cost increased after rounding up the number of trays. Therefore, the total annual cost (TAC, including capital cost and operating cost) remained higher than the real optimal objective. To solve this problem, an integral function is added to the mathematical model to obtain the optimal MEN structure in this study. The application on two universal MEN synthesis mathematical models based on the Composition-Interval Diagram (CID) and stage-wise superstructure illustrate the practicability of the integral function. These modified models are applied to two examples of coke-oven gas sweetening and dephenolization of wastewater. The optimal results obtained in this study are found to be better in comparison to other works in the literature. This study demonstrates that the integral function can solve a series of MEN synthesis problems involving stage columns. Furthermore, a more accurate design scheme for MENS and a structure with lower TAC can be obtained by this function.

Biomax^® is a biodegradable plastic with high thermal resistance. In this study, Biomax^® fiber was hydrolyzed at pH 3.0–10.5 for up to 4 weeks at 80°C. The degradation of the fiber was evaluated based on the degradation products, molecular weight, and scanning electron microscope (SEM) observations. The largest amounts of degradation products were obtained with an alkaline carbonate buffer (pH 10.5). The molecular weight of the Biomax^® fiber decreased remarkably in dilute sulfuric acid (pH 3.0); specifically, it decreased to 23% of the original molecular weight after 1 week. SEM images agreed well with the change in molecular weight. These results reveal remarkable differences between the degradation behavior in alkaline and acidic solutions.