某集气站分离器积液包内防腐技术研究

目的提高分离器积液包的内防腐性能。方法首先通过实验对THF8110-I耐湿热重防腐涂料面漆及带锈底漆所构成的防腐涂层进行了外观、耐磨性、硬度、附着力、耐盐雾、耐腐蚀方面的性能检测,以确定其是否符合现场积液包内防腐的需要。然后通过相关规范设计计算所需牺牲阳极的质量及数量,在此基础上借助BEASY软件模拟,得到不同阳极材料在不同布置方式下积液包内壁的电位分布情况,进行材料优选,并分析阳极布置方式对阴极保护效果的影响。最后,模拟得到阳极在焊接和螺栓连接两种不同固定方式下积液包内壁的电位分布情况,以选择合适的固定方式,螺栓连接时,改变阳极与积液包底端的距离,以确定合适的距离。结果 THF8110-I耐湿热重防腐涂料面漆及带锈底漆所构成的防腐涂层各方面性能均达到标准要求,同种布局方式下,铝阳极对积液包形成的保护电位总是比锌阳极更负,而阳极材料相同时,五种布置方式下积液包内壁的电位范围之差不超过1 mV。与焊接相比,螺栓连接且阳极距离积液包底端为150mm时,积液包内壁的电位分布最为均匀。结论采用防腐涂层结合牺牲阳极保护的方式提高了积液包内壁的防腐能力。其中,防腐涂层由THF8110-I耐湿热重防腐涂料面漆及带锈底漆所构成,牺牲阳极保护方案中,采取四支铝阳极在积液包底端均布的方式阴极保护效果最好,且阳极与积液包的固定方式选择螺栓连接,阳极与积液包底端的距离为150 mm。     

Comparison of masking agents for antimony speciation analysis using hydride generation atomic fluorescence spectrometry

A sensitive atomic spectrometric method for the redox speciation analysis of Sb in water is described. The proposed method is based on the selective generation of stibine from Sb(III) in a continuous flow system using non-dispersive atomic fluorescence spectrometry for detection. The effects of the HCl concentration on the fluorescence intensities of Sb(III) and Sb(V) were investigated. The results indicated that atomic fluorescence emission due to Sb(V) can constructively interfere with the determination of Sb(III). For the determination of Sb(III), four compounds were tested as masking agents to inhibit the generation of stibine from Sb(V). The effects of the concentrations of the masking agents and of HCl on the fluorescence signals from Sb(III) and Sb(V) were studied. The results indicated that citric acid and NaF can successfully suppress hydride generation from Sb(V). To evaluate the developed methodology and the influence of the matrix, the recovery of Sb(III) from natural water that was spiked with different Sb(III) and Sb(V) concentrations was tested.     

Chelant-assisted pulse flushing of a field Pb-contaminated soil

Laboratory experiments on a lead-contaminated soil were carried out to test the effects of chelant addition on metal leachability using column tests. Tests were aimed at studying metal mobilisation upon application of two different chelating agents (ethylenediaminetetraacetic acid [EDTA] and ethylenediaminedisuccinic acid [EDDS]). Column operation was arranged to simulate a flushing treatment in which the chelating agent is applied in a pulse mode to the soil for one bed volume, while deionised water was continuously introduced for the rest of the experiment. Two different concentrations (3 and 5 mmol·kg ^?1 respectively) of the two chelating agents and a control solution (deionised water) were tested in separate experiments; pH, total organic carbon and the total concentrations of Pb, Zn, Fe, Cd, Cu and Ni were monitored during each run. A seven-step sequential extraction procedure was used to evaluate metal partitioning and concentration in the contaminated soil after treatment as a function of depth. The results showed the effect of the nature of flushing solution on the hydraulic behaviour of the columns. Metal concentrations in the leachate increased considerably upon the application of chelants, thus indicating their suitability for metal extraction from contaminated soils. In view of full-scale application of soil flushing, particular concern should also be devoted to ensuring a homogeneous distribution of the solution within the contaminated area and an efficient collection of the exhausted extracting solution, as well as to recovering and recycling the chelating agent used.     

Comparative effects of five chelating agents on testicular toxicity in mice induced by acute exposure to cadmium

The aim of this study was to develop new antidotes for cadmium (Cd) since this metal is known to produce mammalian toxicity. N-p-hydroxymethylbenzyl-D-glucamine dithiocarbamate (HBGD), N-benzyl-D-glucamine dithiocarbamate (BGD), diethyldithiocarbamate (DDTC), 2,3-dimercaptopropanol (BAL), and ethylenediamine-tetraacetic acid (EDTA) were studied for their ability to inhibit the adverse effects induced by Cd on mouse testes. The parameters examined included concentrations of Cd, calcium (Ca), iron (Fe), and zinc (Zn) in testes, lipid peroxidation (LPO) levels in testes, lactate dehydrogenase (LDH) activity in serum and reproductive ability of male mice. Mice injected intraperitoneally (ip) with CdCl₂ (2.5?mgCd?kg^?1) after 30?min or 24?h, were then injected ip with chelating agents (400?µmol?kg^?1). Cd increased the concentrations of testicular Ca, Cd, Fe, Zn, and LPO levels as well as the activity of LDH in serum. HBGD and BGD effectively prevented the increase in above indices, and improved the reproductive ability weakened by exposure to Cd. The results suggested that HBGD and BGD are more effective detoxificants in the case of testicular toxicity in mice induced by acute exposure to Cd.     

Mobilization kinetics of heavy metals from contaminated river sediment of northern Taiwan by complexing agents

A laboratory experiment was used to investigate the mobilization kinetics of heavy metals from the sediment of a contaminated river located in northern Taiwan with varied concentrations of NTA and EDTA. We found that there were two stages of desorption in the mobilization of heavy metals from the sediment. As the concentrations of NTA and EDTA ranged 0–3.9 x 10^‐4M (0–100mg/l) and 0–2.7 x 10^‐4M (0–100mg/l) respectively, the mobilization percentages of heavy metals were proportional to the logarithm values of the concentrations of NTA and EDTA. The physical meaning of the multiple first‐order reaction was significant for the actual condition, but occasionally, it had more errors for Cu and Zn in the initial phase. The two‐constant model was most appropriate for describing the rates of mobilization of Pb, Cu, Zn, and Cr. The agreement between the diffusion model and the experimental data was satisfactory for Pb, Cu, Zn, and Cr only in the initial 5 h.     

海上风电基础阴极保护技术研究

目的 探究外加单一电流阴极保护（Impressed Current Catholic Protection,ICCP）系统、单一牺牲阳极保护（Sacrificial Anode Cathodic Protection,SACP）系统以及SACP与ICCP系统联合保护3种工况下对海上风电基础的最优保护方案。方法 通过对3种工况进行数值模拟计算,对比不同工况下阴极保护系统对风电基础的保护效果。确定最优工况后,构建大比尺模型对最佳工况进行该工况下的实海测试实验。结果 单一SACP、单一ICCP系统以及SACP与ICCP系统联合保护3种工况下,风电基础保护电位区间分别为–926～–881 mV、–1 018～–985 mV和–984～–963 mV。实海测试实验中,导管架电位分布为–1 029～–912 mV。数值模拟结果与实验结果基本一致。结论 当SACP与ICCP系统联合保护时,保护效果最好。随着输出电流的逐步增大,风电基础模型逐步趋于过保护状态。