二氧化碳对发电机内冷水pH与电导率的影响

应用热力学方法,导出了空气中的CO2对用氨水和NaOH做碱化剂时,在开放内冷水体系及封闭内冷水体系的pH和电导率的影响的多个关系式,并用计算机作图展示了这些关系;得出了空气中的CO2对除盐水的pH和电导率影响很大,开放内冷水体系不能满足电导率和pH值同时达标的要求,以及用碱化法抑制发电机铜导线腐蚀时用NaOH做碱化剂比用氨水更适宜等三点结论;提出了加强内冷水体系的密闭性,或在内冷水箱上加装防污呼吸器的建议。     

发电机内冷水中pH对铜沉淀影响研究

计算发电机碱性水化学工况运行过程中,不同pH条件下铜离子的形态,并通过实验研究pH值与生成沉淀物的关系,采用SEM-EDS和XPS对滤膜截留沉淀物进行分析。结果表明,当pH>8.0时,溶液中以CuO沉淀为主。由于内冷水中铜多以氧化物形式存在,采样后测得的铜离子含量不能完全代表空芯铜导线的腐蚀情况,需核算过滤器、离子交换器及反冲洗时内冷水中铜离子含量。     

发电机内冷水中pH对铜沉淀影响研究

计算发电机碱性水化学工况运行过程中,不同pH条件下铜离子的形态,并通过实验研究pH值与生成沉淀物的关系,采用SEM-EDS和XPS对滤膜截留沉淀物进行分析。结果表明,当pH8.0时,溶液中以CuO沉淀为主。由于内冷水中铜多以氧化物形式存在,采样后测得的铜离子含量不能完全代表空芯铜导线的腐蚀情况,需核算过滤器、离子交换器及反冲洗时内冷水中铜离子含量。     

离子交换微碱化处理发电机内冷水试验研究

采用离子交换微碱化技术处理发电机内冷水,将内冷水中微量溶解的中性盐Cu(HCO3)2转化为Na0H,调节溶液成微碱性,从而有效地抑制了铜导线的腐蚀。现场旁路模拟试验结果表明：在小交换柱内填装等工作交换容量的钠型、氢氧型离子交换树脂后,能将Cu^2 平均质量浓度为371．0μg/L的微酸性内冷水转变成几乎不含Cu^2 的微碱性水,出水pH的变化范围为7．60～8．95。离子交换柱之前和之后的铜试片试验结果显示：交换柱前的内冷水具有腐蚀性．而经交换柱处理后的内冷水具有抑制铜导线腐蚀的功效。     

发电机内冷水单床钠型混床碱化处理法的应用

本文论述了发电机内冷水系统采用单床钠型混床碱化处理法的可行性,该方法利用发电机自带的单床离子交换器,在基本不增加投资的情况下,通过优化离子交换器树脂的再生,只采用单一钠型混床和适当的运行调整就能够调节和控制内冷水水质在期望值范围内。经过长周期的实践证明了该方法简单、稳定、可靠,能最大程度的降低发电机空心铜导线的腐蚀,确保发电机组安全稳定运行。     

发电机内冷水系统的化学清洗

论述了发电机内冷水系统结垢的原因和进行化学清洗的依据。并介绍了实施化学清洗的系统和工艺。     

发电机内冷水的处理与监督

本文论述发电机内冷水系统发生腐蚀的原因及危害。结合实际情况,全面介绍了现场实用的各种处理方法,并分析了各种处理方法的优缺点及水质监督内容。     

发电机内冷水水质调控处理技术

详细论述了近年来发电机内冷水水质调控处理技术与工艺的进展与应用情况，并对各种方法进行了简要评价。这些方法主要有离子交换法、缓蚀剂法、碱化处理法、氧量控制法等。同时，对内冷水处理技术的发展动态作出展望与建议。     

发电机内冷水系统的化学清洗

内冷水系统的腐蚀产物沉积在铜导线表面上造成水流面积变小,阻力增大,内冷水流量减小,发电机定子线棒温升增加。采用适当的化学药剂对发电机内冷水系统进行化学清洗,可除去铜导线内表面结垢和腐蚀产物,提高换热效率,降低定子线棒的温度,确保发电机安全经济运行。     

发电机内冷水防腐处理技术

发电机内冷水水质的优劣直接影响发电机的安全经济运行。发电机内冷水处理方法有除盐处理、缓蚀剂处理、碱化处理、超净化处理等,分析了各种处理方法的特点,用以正确选择发电机内冷水处理方法。     

反渗透系统给水电导率与pH的系统影响

测试并分析了一、二级反渗透系统给水电导率及pH与系统透盐率和浓淡水pH之间的关系.测定了给水pH在6～8、给水电导率在400～1 000μS/cm范围内的系统透盐率较低,且pH为7.5、电导率为500μS/cm的系统透盐率最低.此测试与分析为反渗透技术提供了重要的运行与设计依据.     

pH Sensitive polypropylene porous membrane prepared by grafting acrylic acid in supercritical carbon dioxide

pH sensitive membrane was prepared by grafting acrylic acid (AA) on the porous polypropylene (PP) membrane using supercritical (SC) CO₂ as a solvent. The monomer (AA) and the initiator (benzyl peroxide, BPO) were impregnated into the PP substrate with the aid of SC CO₂, and were grafted onto the microporous PP substrate. The grafted membranes were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), and the water permeability of the virgin and grafted membranes were determined at different pH values. It was demonstrated that the grafting degree (Dg) could be easily controlled by varying operating conditions, such as the monomer concentration, pressure, and temperature during the soaking process. The water permeation of the virgin membrane is nearly independent of pH. However, the water permeation of grafted membranes decreases dramatically with pH as the pH varies from 3 to 6 because the conformation of the PAA changes significantly with the pH of the contacting solution.     

雾化氛围中二氧化碳调节含氨溶液pH值的研究

利用二氧化碳作为模拟烟道气,考察了去离子水、氨水、碱性氨氮废水吸收二氧化碳过程中液体雾化量、二氧化碳流量及反应时间等对反应速率的影响。根据反应过程中液体p H值的变化优化了反应条件。结果表明:雾化氛围加快了反应速率,从而在一定时间内增大了液体p H值的降低幅度;优选的液体雾化量0.376 m L/min,二氧化碳流量15 m L/min。此外,二氧化碳能够明显降低碱性氨氮废水的p H值,因此为烟道废气处理氨氮废水的实际应用提供了可行性参考。     

不同pH下Ag-TiO_2薄膜的光催化性能研究

以钛酸丁酯为钛源,采用溶胶-凝胶法制备Ag-TiO2溶胶,将其涂覆在载玻片上制得高光催化活性的透明薄膜。在n[Ti(OC4H9)4]∶n(C2H5OH)∶n[NH(C2H4OH)2]∶n(H2O)∶n(AgNO3)=1∶18∶0.5∶1∶0.032的前提下,通过改变pH值和两种不同照射光源,对甲基橙溶液进行光催化降解。结果表明,当pH值在3~6的范围,不论哪种照射光源,甲基橙降解率可达到83%。红外光谱、能谱、热重-差热、透射电镜和原子力显微镜等测定,结果表明,光催化薄膜由粒径10~20 nm的AgNO3和TiO2颗粒构成,锐钛晶形结构在500~550℃转变充分。     

循环冷却水pH-碱度的理论计算和分析

循环冷却水中和空气中的CO2之间存在交换,由于循环冷却水系统的连续运行,冷却水中和空气中的CO2达到平衡,此时的pH可由公式准确计算。pH的控制范围同循环水的浓缩倍率有密切关系,并对节水和腐蚀有重要影响。     

发电机内冷水处理机理与技术综述

发电机内冷水在空心铜导线内运行,这一特殊环境要求其必须达到绝缘、不腐蚀、不结垢的要求。影响内冷水腐蚀和堵塞的因素包括溶解氧、p H、CO2等,通过提高内冷水p H和控制溶解氧含量能够解决这一问题。根据原理不同,内冷水处理技术可分为缓蚀剂法、换水法、小混床法、碱性处理法和氧含量控制法,介绍了这些方法的原理和应用,并对每种方法进行了评价。对于目前国内处理技术存在的小混床周期短、p H偏低等问题提出了建议。     

Mathematical modelling and in situ determination of pH in complex aqueous solutions during high-pressure carbon dioxide treatment

High-pressure carbon dioxide (HPCD) treatment is currently considered as an attractive non-thermal process for preserving food. Since the first level of interaction between HPCD and the bacterial cells is lowering of the pH, knowledge of the pH of a food product in contact with CO₂ at high-pressure conditions is essential for a better understanding of the inactivation mechanism of HPCD. Therefore, a mathematical model was developed to predict the pH in complex aqueous food systems in contact with CO₂ at high-pressure conditions as function of pressure, temperature and buffer capacity. In addition, a spectrofluorometric method using calcein as fluorescent pH indicator was designed for the in situ measurement of the pH of complex aqueous systems in contact with pressurized CO₂ as function of pressure (10.5-18.0 MPa), temperature (25-35 °C), initial pH (4.0-8.0), working volume ratio (41.6-70.0%) and broth composition (0.1 M citrate buffer, 0.1 M phosphate buffer and 10% whey protein). To mimic a complex matrix, the bacterial Brain Heart Infusion (BHI) broth was used.In general, there was a good agreement between the measured and predicted pH values. Only for the lowest initial pH of the broth, a discrepancy between the measured and calculated pH values was noticed, implying that the proposed model needs some further refinement to properly take into account non-ideality of the liquid phase. Furthermore, the pH of the broth was significantly influenced by the initial pH of the solution but was not dependent on pressure, temperature and working volume ratio. The addition of complementary buffers to the broth also influenced the pH drop and this effect was dependent on the initial pH of the solution.