Advanced Materials Research Vols. 550-553

Abstract: The blends was obtained by adding appropriate content of polyethylene and other additives such as lubricant and antioxidant in the polypropylene.Through the polarized light micrographs of the blends, we found that the mixer had a multiphase system after they had been processed in the twin screw extruder. The complete spherical crystal in polypropylene was divided into small fragments. A great number of sample with different formula has been tested. The results of the experiment showed that the impact property of mixer was improved. When the content of HDPE in PP is 30 percent, its comprehensive electrical and mechanical properties are best. The blend was completely able to meet the requests for the insulation materials of the cable of detection.

Abstract: Polyacrylamide/MgCl₂ hybrid hydrogel desiccant was prepared from magnesium chloride and polyacrylamide by aqueous solution polymerization. The hybrid hydrogel was synthesized and characterized by X-ray diffraction. The effect of the experimental factors such as content of magnesium chloride, concentration of cross-linking agent, initiator content on hygroscopic performance of the hybrid hydrogel were investigated, furthermore, the hygroscopic swelling kinetic process of the hybrid hydrogel was studied. The results indicate that hybrid hydrogel possessed preferable hygroscopic property under the optimum conditions, the hygroscopic swelling degree achieving 172%. The hygroscopic swelling process of the hybrid hydrogel follows the kinetic pseudo-second-order model, in addition, the swelling rate decreases with the increase of relative humidity.

Abstract: Extraction conditions (flow rate of CO₂, time of extraction, pressure of extraction, temperature of extraction, type of entrainer, content of plasticizer) on the impact of the yield coefficient were discussed, and the best technical parameters were determined in this paper. The results show that the best time is 180 min, pressure is 25 MPa, temperature is 55 °C, flow rate is 25 L/h, and entrainer is 200 mL petroleum ether. The plasticizer’s yield coefficient can reach 78.26% under the conditions, and the performance and structure of resin and plasticizer are almost the same after being extracted.

Abstract: The thermal and kinetic behaviors of the sheath and insulation material taken from the fire-retardant PVC cable have been investigated in the air atmosphere by using thermogravimetrical (TG) analysis method. The degrading activation energy (Ea) of the material were calculated through Kissinger and Flynn-Wall equations based on the TG and DTG curves. The results showed that there were three steps during the degrading process of the FR PVC cable sheath and insulation materials, and the degradation rate increased with the increase of the heating rate. The average activation energy of the sheath and insulation material obtained from Flynn-Wall equation were 118 kJ/mol and 134kJ/mol, respectively.

Abstract: A cationic amphiphilic copolymer was synthesized with acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), monomer B by solution copolymerization. Through the orthogonal test, the optimum synthesis condition was obtained as follow: the solid content of the polymerization system is 10%, the pH value is 4.0, the polymerization temperature is 60°C, the concentration of the initiator is 0.06%, and the monomer ratio of m (AM): m (DMDAAC): m (monomer B) is 70:10:20. The copolymer was used for the filtration aiding in the wet process phosphoric acid. The filtration rate of the gypsum slurry is increased by 4.8 times, and the filter cake moisture is reduced by 11.79%, with the addition of PADB. The mechanism of filtration aiding was also researched, which shows that PADB can change the mean diameter of crystals and agglomerate the tiny crystals; PADB can decrease the surface tension of the filter liquor and enhance the hydrophobicity of the gypsum.

Abstract: This paper is devoted to the experimental study of air jet in a cylindrical cavity initially containing air at rest. A set of experiments has been performed to analyze the velocity field in the cavity. The experimental data have been obtained by means of hot wire anemometry, in different sections of the cavity. In addition, flow visualizations were performed using carbon dioxide in solid form. Parallel to this work, we undertook a theoretical study on the same laminar flow, with the same geometric configuration, and it will be the subject to an incoming paper.

Abstract: A new method that phosphate ore was reduced by carbon under fluidization was introduced to produce yellow phosphorus, and we made thermodynamic analysis of the process and investigated the effect of coke content, flow of nitrogen gas, and temperature on percent reduction of phosphate ore. The thermodynamic analysis indicated that the beginning reaction temperature of phosphate ore with mole ratio of silica-to-lime equal to 3 decreased by 8.8°C with increasing 0.1 atm N₂ partial pressure when the system total pressure was 1 atm. The experiment results showed that percent reduction of phosphate ore increased with increasing the coke content, the flow rate of nitrogen gas below 600 L/h and the temperature. The reduction rate in the fluidized bed reactor was better than that in a fixed bed under the same temperature, particularly lower temperature. The temperature was a dominant factor, the influence of which on reaction was greater than any other factors.

Abstract: This paper discusses the effect of adding pump-around circuits and reducing stripping steam flow rate on the improving energy efficiency and increasing processing capacity of the atmospheric column in a refinery plant by using commercial simulator. It is shown that both the capacity and energy efficiency of the atmospheric column can be increased by adding pump-around circuits and reducing stripping steam flow rate. The modifications discussed in this paper will affect the separation of the atmospheric column in some way. However, the product qualities can still meet the specifications, if the changes of the parameters are not significant. Therefore, the above issues should be considered in the modifications overall.

Abstract: The effect of adjusting feed thermal conditions on the throughput of complex distillation columns was investigated by using the concept of the Fractional utilization of area (FUA) proposed by Liu and Jobson (Chem. Eng. Res. Des, 2004, 82, 3-9). The FUA curve can be used to identify the bottleneck of an existing complex distillation column when the throughput is to be increased. According to the shape of the FUA curve, it can be known that how to adjust feed thermal condition of a complex distillation column to increase its throughput. The results show that the FUA method is a powerful tool for complex distillation column analysis.

Abstract: Because of the large number of operating and equipment parameters of the reactive distillation(RD) and a strong coupling between them, it is difficult to find the optimal process parameters. A novel hybrid method on process parameters optimization of methyl tertiary butyl ether (MTBE) RD was developed in the paper. MTBE RD process was firstly simulated with Aspen Plus. Then based on the MTBE RD model, sensitivity analysis of various parameters was accomplished to determine the key decision parameters. After that, the orthogonal numerical tests were performed in feasible fields to obtain nearly optimal parameters. Finally, with the orthogonal numerical test results, the least square method was used to regress equation, which showed the relationship between objective function and the key decision parameters, thus determining the optimal operating parameters and equipment parameters. Results of analysis indicated that the combination of orthogonal numerical test and the least square method can be attractive since the number of tests was reduced substantially while the specification of the products can be met.