Zhi Ping Zhu

Research Progress for Determination of the Antioxidant Content in Transformer Oil

Under the actions of dissolved oxygen, temperature, electric field, electric arc, moisture, impurities and metal catalysts, transformer oil in operation will undergo oxidation and cracking, which may result in production of large quantities of peroxides, alcohols, aldehydes, ketones and acids. To improve the oxidation stability of oil, the antioxidants should be added into the transformer oil before operation. This paper mainly introduced the oxidation process of transformer oil, the harm of transformer oil oxidation and the method for the determination of the T501 antioxidants content in transformer oil. It also forecast the development trend of the electrochemical test in the determination of T501 antioxidants content.

Diagnostic Analysis of Boiler Make-Up Water Treatment System in Taishan Power Plant

The boiler make-up water pretreatment system and desalination system of 2×1000MW units in Taishan power plant were investigated and analyzed,and their corrosion risk were assessed . The results showed that the change of seasons had no effect on the dosage of coagulate in boiler make-up water pretreatment system and the system had advantages of economic operation, simple maintenance, however, corrosion risk might exist in equipment; for desalination system, carbon remover could be omitted and it had a large cycle water production, and the water quality of the mixed bed is good, however, the effect of iron removal and high efficiency filter backwashing is poor, In addition, corrosion existed in both acid and alkali regeneration system as well as in drainage system, steam turbine and effluent treatment equipment.

Alternative Working Electrode for the Determination of the Antioxidant Content by Electrochemical Techniques

T501 is an antioxidant widely used in transformer oil. The content of T501 in transformer oil can be detected by electrochemical techniques, however, in the process of condition optimizing for electrochemical measurement, people haven’t done in-depth study the effect of working electrode on T510 antioxidant electrochemical measurement. This paper mainly introduced the alternative working electrodes for the determination of the antioxidant content. Through researching the electrochemical properties of T501 antioxidant by the electrochemical workstation, it is confirmed that the graphite electrode is the best working electrode in the electrochemical measurement of T501 antioxidant content.

Erosive Ions in Industrial Boiler Water on the Corrosion Behavior of Water-Wall Tubes

The maximum allowable content of chloride ion in industrial boiler water is closely related to the concentration ratio and operating conditions, the reasons for industrial boiler can not be operated under too high concentration ratio is due to the limit of Cl- content. There are many studies for the electrochemical corrosion behavior of carbon steel caused only by chloride ion, but few studies for calcium and bicarbonate ions on the electrochemical corrosion behavior of carbon steel. In order to study the corrosion of water-wall tubes for industrial boilers (20# carbon steel) caused by chloride ion, the erosive anion (Cl) and Ca2+, electrochemical impedance spectroscopy and Tafel polarization techniques were performed. Autoclave static experiments were performed to study the corrosion inhibition property of carbon steel with 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) additive in industrial boiler water medium. The results showed that Cl- could promote the corrosion of carbon steel obviously, HEDP has a good corrosion inhibition effect on 20# carbon steel at a concentration of 25 mg/L; Lower concentration Ca2+ in industrial boiler water could promote the corrosion while addition of higher concentration Ca2+ could inhibit the corrosion. It can provide a reference for the safe operation of the industrial boiler.

Influence of Water Content on Corrosion Properties of 20 Steel in Semi-Desertification Soil

The influences of water content on corrosion behavior of grounding steel in semi-desertification soil were studied by polarization curve technique and weightlessness method.The tested specimen surface was characterized by scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD).The experiment results show that moisture has a great influence on corrosion of steel,the corrosion rate of 20 steel increased to a maximum at a value and then decreased.To anslysis the formation mechanism of soil corrosion products.

Corrosion Behavior for Water Wall Tube Material of 600MW Supercritical Thermal Power Units

The influence of chloride ions and sulfate ions on 15CrMoG and 12Cr1MoVG respectively in the simulated Oxygenated Treatment water chemistry conditions with SO42- and Cl- of different concentrations is studied by using polarization curves, electrochemical impedance spectroscopy (EIS) and high temperature coupon tests. The results show that under the experiment condition of room temperature, the two materials are very prone to corrode in solutions containing SO42- and Cl- and the corrosion rate is enhanced with increasing SO42- and Cl- concentration. The corrosion resistance of 15CrMoG is stronger than 12Cr1MoVG for SO42- and Cl-. The corrosivity on 15CrMoG and 12Cr1MoVG of SO42- is lower than Cl-. Under high temperature conditions, the corrosion resistance of 15CrMoG stronger than 12Cr1MoVG in SO42- solutions.

Electrochemical Corrosion Behavior of Ultra-Supercritical Unit Waterwall Tube Material in Simulated Solution of Oxygenated Treatment at Room Temperature

The electrochemical corrosion behavior of ultra-supercritical unit waterwall tube material in simulated solution of oxygenated treatment (OT) with different concentration of Cl- and SO42- at room temperature was investigated by electrochemical impedance spectroscopy and Tafel slopes. The results showed that the polarization resistance Rp values decreased and corrosion current density (icorr) increased with increasing Cl-/ SO42- concentration in solution. Corrosion potentials (Ecorr) decreased with increasing Cl-/ SO42- concentration in solution.

Electrochemical Evaluation Method for Soil Corrosion Properties in Grid Substation

Soil corrosion is the main reason of corrosion failure for substation grounding grids. To explore electrochemical evaluation method for soil corrosion of substation grounding grids would effectively ensure the safe operation of power grids. This paper discussed the main several kinds of soil corrosive electrochemical research methods and application. These methods played an important role on researching soil corrosion mechanism, soil corrosivity and corrosion behavior.

Degradation of Trace Oil by Nano-TiO2 Loaded on Hollow Float Beads

The nano-TiO2 photocatalysts which loaded on hollow float beads were prepared by sol-gel process. The hollow float beads as carrier was modified by H2SO4 and the TiO2 sol was obtained by tetrabutyl titanate, the modified hollow float beads was added into TiO2 sol, the TiO2 gel was obtained, then calcined at 450°C, 500°C, 550°C respectively and obtained as-produced samples. Their property were characterized by TGA, XRD and SEM, Their photoactivity was evaluated by the photodegradation of the trace oil from fossil-fired power plant condensate under a series of temperature（15°C~45°C）, pH value（2~14）, initial oil concentration（5mg/L） and catalysts dosage（2.500g/L, 4.000g/L, 5.000g/L, 6.000 g/L, 7.500g/L, 10.000g/L）, the experimental results showed that as temperature at 35°C, pH value at 10, catalysts dosage at 5.000g/L and calcined temperature at 500°C, the trace oil degradation rate could exceed 90% in 12 h, the catalysts could provided a efficient method to degradate the trace oil.

Preparation and Photodegradation of Humic Acid by a Y3+-Doped ZnO/TiO2 Composite

Aim to remove soluble humic acid (HA) in super-critical boiler make-up water, Y3+-doped ZnO/TiO2 composites were prepared using a solid-phase synthesis method, Their properties were characterized by x-ray diffraction, transmission electron microscopy, and UV-visible diffuse reflection spectroscopy (DRS); their visible light photoactivities were evaluated by the photodegradation of humic acid in an aqueous solution under sunlight irradiation.. The experiment results showed that Y3+-doped samples had a higher absorbance than pure TiO2, and a red shift appeared in the DRS spectrum; The Y3+-doped ZnO/TiO2 multiplex nanocomposite can expand the wavelength range for light absorption and increase the sunlight utilization efficiency. Samples with 3% Y3+ and 27% ZnO have the highest photoactivities.