A more precise method to evaluate kinetic leakage of anion exchange resin used in condensate polishing of power plant

Sulfate mass transfer coefficient(MTC) is a sensitive parameter to evaluate the kinetic leakage of anion exchange resin used in condensate polishing system of thermal and nuclear power plant.However,a sufficiently precise determination method has not been well established.In this paper,the final expression of sulfate MTC derived based on plug flow reactor model is the same as Harries' model,which is widely acknowledged in this field.In the determining system we constructed,in-situ calibration of the concentration of sulfate and its cation conductivity was conducted and sulfate MTCs of four typical strongly basic anion exchange resin samples were determined.The systematic error is 8.26% and the calibrated curve used for quantifying sulfate is obtained.The repeatability and reproducibility standard deviation are 0.05×10^(-4) m·s^(-1) and 0.07×10^(-4) m·s^(-1) respectively,which are lower than previous works.By controlling test condition accurately,this study has developed a more precise sulfate MTC determining method.This method provides a basis for further research.

Application of Silica Aerogel Carrier via Supercritical Drying for Fragrance Controlled-release

Silica aerogel with different hydrophilicities were prepared from tetramethoxysilane,Methymethoxysilane,tetramethoxysilane-propyltrimethoxysilane,or tetramethoxysilane-phenyltrimethoxysilane mixtures via supercritical drying process(labelled as TMOS-AG Me-TMOS-AG,Pr-TMOS-AG,or Ph-TMOS-AG,respectively).Three fragrances,including geraniol,ethyl vanillin,and menthol,were loaded to TMOS-AG.The thermal analysis confirmed all loading fragrances are stable until over 200℃.And among all fragrances,geraniol presented the maximum loading contents(L_(m)).Concentration dependences indicated the geraniol was mono layer absorbed.Py-GC/MS of geraniol in TMOS-AG under both N_(2)and mimic air atmosphere(90%N_(2)and 10%O_(2))confirmed that loaded geraniol could be thermally controlled-released beginning at 200℃.As N_(2)absorption confirmed,even absorption/desorption equilibrium constant(k)was determined mainly by hydrophilicity of silica aerogels,and the maximum loading contents(L_(m))were influenced more by the pore size.Due to mono layered absorption,bigger pores usually give less specific areas and less absorbing sites for geraniol,and then present lower L_(m).

Silicone Chain Extender for Recycled Polyethylene-terephthalate with Higher Flexibility

To decrease the modulus and increase the mechanical properties of recycled PET by introducing the flexible segments, the recycled polyethylene-terephthalate(PET) was modified by the chain extender produced with 2, 4, 6, 8-tetramethyl-2, 4, 6, 8-tetra(2, 3-epoxypropoxy) propylcyclotetrasiloxane by the hydrosilylation reaction. Different percentages of chain extender were used in order to investigate the effect of chain extender content on the modulus of PET. The dynamic mechanical analysis was performed on PET samples, which showed that Tg of PET was firstly raised by the addition of chain extender and then decreased. Small amplitude shearing test performed on PET samples confirmed that the addition of the flexible segments could remarkably decrease the modulus of PET, which would be helpful for the extrusion process. The entanglements from branches were also influenced by the addition of extender.

Silicone Modified Polyesters Vulcanizable at Room Temperature for Anti-corrosion Coatings on Tinplate

Trimethoxysilyl Polyester(TMOS-PET)was prepared via hydrosilylation of trimethylsilane with acryl-terminated polyester.Copolymerization of TMOS-PET with trimethylmethoxysilane,tetramethoxysilane,and/or dimethyldimethoxysilane give silicone modified polyesters(Si-PET)containing=(SiO_(2))=,-(CH_(3)SiO_(3/2))=,and/or-((CH_(3))_(2)SiO)-units.Coatings from Si-PET were formed on tinplate surface via room temperature vulcanization with applicable curing time(the quickest tact free time and completely drying time are 2 h and 15 h,respectively).Mechanical properties,thermal stability,chemical resistance,and anti-corrosion of coatings were detected.Although the flexibility of the coatings were lowered by=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units,adhesion and thermal stability of coatings were both improved.On the contrary,(CH_(3))_(2)SiOunits seem to improve the flexibility,while decrease the adhesive force for less crosslink points.Generally,the silicone modified polyesters act as an effective shielding for tinplate.According to electrochemical impedance spectroscopy(EIS),the electric resistance of coatings(Rc)were improved about 25 times and open circuit potential(OCP)increased about 0.10 V compared to the control.The chemical resistance and anti-corrosion of the coatings were decreased slightly after=(SiO_(2))=and-(CH_(3)SiO_(3/2))=units were added,but they could be greatly improved by-(CH_(3)SiO_(3/2))=units.Specially,after adding-(CH_(3)SiO_(3/2))=units,coatings give doubled Rc,and its OCP is about 0.20 V higher than the control.

Preparation and Properties of Conductive Foamed Silicone Rubber

The conductive foamed silicone rubber was prepared by Polymethylvinylsiloxane(PMVS)mixed with acetylene black,fumed silica,and AC foaming agent(azodicarbonamide).Influences of fillers on the microstructure,electrical conductivity and mechanical property were discussed.The results showed that the pore structure was affected by acetylene black.Acetylene black delayed the vulcanization speed of silicone rubbers,leading to bigger pores.Higher content of acetylene black decreased the mechanical properties and the electrical resistivity of rubbers.Fumed silica increased the mechanical properties and limited the aggregation of gas.Higher content of fumed silica led to small and obturator pores generated.Higher content of fumed silica increase the mechanical properties and the electrical resistivity of rubbers.AC foaming agents generated more gas,leading to bigger and irregular pores which affected the mechanical properties negatively,meanwhile AC foaming agents increased the conductivity of rubbers.