It is known that one of the causes of pitting corrosion of copper tubes is residual carbon on the inner surface. It was confirmed that type I” pitting corrosion of the copper tube is suppressed by keeping the residua...It is known that one of the causes of pitting corrosion of copper tubes is residual carbon on the inner surface. It was confirmed that type I” pitting corrosion of the copper tube is suppressed by keeping the residual carbon amount at 2 mg/m<sup>2</sup> or less, which is lower than that of the type I’ pitting corrosion, or by removing the fine particles that are the corrosion product of galvanized steel pipes. The developed water treatment chemical was evaluated using three types of copper tubes with residual carbon amounts of 0 mg/m<sup>2</sup>, 0.5 mg/m<sup>2</sup>, and 6.1 mg/m<sup>2</sup>. The evaluation was conducted for three months in an open-circulation cooling water system and compared with the current water treatment chemical. Under the current water treatment chemical conditions, only the copper tube with a residual carbon amount of 6.1 mg/m<sup>2</sup> showed a significant increase in the natural corrosion potential after two weeks, and pitting corrosion occurred. No pitting corrosion and no increase in the natural corrosion potential were observed in any of the copper tubes that were treated with the developed water treatment chemical. In addition, the polarization curve was measured using the cooling water from this field test, and the anodic polarization of two cooling waters was compared. For copper tubes with a large amount of residual carbon, the current density near 0 mV vs. Ag/AgCl electrode (SSE) increased when the developed water treatment chemical was added.展开更多
Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution i...Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.展开更多
Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for wate...Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.展开更多
An innovative design for the treatment and reuse of grey water is presented in the form of a grey water dam which is an outgrowth of the vertical grey water tower. A hydraulic equation has been formulated and is prese...An innovative design for the treatment and reuse of grey water is presented in the form of a grey water dam which is an outgrowth of the vertical grey water tower. A hydraulic equation has been formulated and is presented in this paper which is used to determine the seepage path within the grey water dam, and determine the dimensions of the dam components. The hydraulic equation model also helps in avoiding soil piping problems by keeping the phreatic line within the grey water dam. Vegetables are planted around the surface of the dam as a reuse option while helping recycling of water in the form of evapotranspiration. A successful pilot trial of this dam was run in Mnyamatsini area in Swaziland which can accept grey water from multiple households.展开更多
Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well ...Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3) exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4) Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.展开更多
文摘It is known that one of the causes of pitting corrosion of copper tubes is residual carbon on the inner surface. It was confirmed that type I” pitting corrosion of the copper tube is suppressed by keeping the residual carbon amount at 2 mg/m<sup>2</sup> or less, which is lower than that of the type I’ pitting corrosion, or by removing the fine particles that are the corrosion product of galvanized steel pipes. The developed water treatment chemical was evaluated using three types of copper tubes with residual carbon amounts of 0 mg/m<sup>2</sup>, 0.5 mg/m<sup>2</sup>, and 6.1 mg/m<sup>2</sup>. The evaluation was conducted for three months in an open-circulation cooling water system and compared with the current water treatment chemical. Under the current water treatment chemical conditions, only the copper tube with a residual carbon amount of 6.1 mg/m<sup>2</sup> showed a significant increase in the natural corrosion potential after two weeks, and pitting corrosion occurred. No pitting corrosion and no increase in the natural corrosion potential were observed in any of the copper tubes that were treated with the developed water treatment chemical. In addition, the polarization curve was measured using the cooling water from this field test, and the anodic polarization of two cooling waters was compared. For copper tubes with a large amount of residual carbon, the current density near 0 mV vs. Ag/AgCl electrode (SSE) increased when the developed water treatment chemical was added.
基金financially supported by the National Natural Science Foundation of China(No.51775204)
文摘Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.
基金supported by international cooperation program for science and technology funded by the Ministry of Science,ICT&Future Planning(NRF-2014K1A3A1A09063208)
文摘Electrochemical water treatment is an attractive technology for water desalination and softening due to its low energy consumption. Especially, capacitive Deionization(CDI) is promising as a future technology for water treatment. Graphene(rGO) has been intensively studied for CDI electrode because of its advantages such as excellent electrical conductivity and high specific surface area. However, its 2D dimensional structure with small specific capacitance, high resistance between layers and hydrophobicity degrades ion adsorption efficiency. In this work, we successfully prepared uniformly dispersed Fe3O4/rGO nanocomposite by simple thermal reactions and applied it as effective electrodes for CDI. Iron oxides play a role in uniting graphene sheets, and specific capacitance and wettability of electrodes are improved significantly;hence CDI performances are enhanced. The hardness removal of Fe3O4/rGO nanocomposite electrodes can reach 4.3 mg/g at applied voltage of 1.5V, which is 3 times higher than that of separate r GO electrodes.Thus this material is a promising candidate for water softening technology.
文摘An innovative design for the treatment and reuse of grey water is presented in the form of a grey water dam which is an outgrowth of the vertical grey water tower. A hydraulic equation has been formulated and is presented in this paper which is used to determine the seepage path within the grey water dam, and determine the dimensions of the dam components. The hydraulic equation model also helps in avoiding soil piping problems by keeping the phreatic line within the grey water dam. Vegetables are planted around the surface of the dam as a reuse option while helping recycling of water in the form of evapotranspiration. A successful pilot trial of this dam was run in Mnyamatsini area in Swaziland which can accept grey water from multiple households.
基金Supported by the Basic Science Center Project of National Natural Science Foundation of China(72088101)Scientific Research and Technology Development Project of CNPC(2021ZG12)National Key R&D Plan/Key Project of International Scientific and Technological Innovation Cooperation Between Governments(2018YFE0196000).
文摘Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3) exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4) Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.