Aluminum silicate scale formation and inhibition (2): scale solubilities and laboratory and field inhibition tests

The solubilities of pure silica, iron-silicate and aluminum-silicate scales were measured in water from 25–250°C in a laboratory pressure reactor. Iron- and aluminum-silicate scales are significantly less soluble than pure amorphous silica. Aluminum- and iron-rich silica scales at equilibrium conditions are predicted to deposit from near-neutral, low salinity brines at temperatures that are 25 and 75°C above the saturation point for pure amorphous silica, respectively. This laboratory study demonstrates that higher brine injection temperatures are required to mitigate aluminum- and iron-rich silica scaling compared with pure amorphous silica. In a laboratory scale test, pure amorphous silica and aluminum-rich silica deposition rates have been measured at high degrees of supersaturation in the presence of potential inhibitors. Scale deposition was best inhibited by brine pH modification techniques. A commercially available dispersant successfully inhibited amorphous silica scaling, but exacerbated aluminum silicate scaling. Scale inhibition was also achieved in the presence of aluminum complexing\sequestering agents in a patent-pending process. Screening of these potential silica- and aluminum-silicate scale inhibitors in the laboratory will focus the efforts of ongoing field pilot scale testing. The effect of complexing\sequestering agents on scale inhibition was monitored in preliminary field pilot tests. These complexing agents achieved 25% to 80% aluminum silicate scale inhibition.     

火电厂水力输灰系统阻垢防垢研究

讨论了灰水输送系统的防垢措施及阻垢的剂阻垢机理,并对电厂灰中氧化钙含量丰富的神府东胜煤进行了阻垢防垢试验研究,分别讨论了不同阻垢剂配方下的阻垢特性,阻垢率以及采用钢橡复合管,灰水预沉淀池的阻垢防垢效果,并对几种方法作了比较分析。     

超声波阻垢与除垢技术研究进展

介绍了超声波工作原理及超声波阻垢与除垢的机理,并以换热系统、采油系统、锅炉系统、蒸发系统及燕化公司化学品事业部的化工系统为例,介绍了国内外在超声波阻垢与除垢方面的应用进展情况。超声波阻垢与除垢技术实现了阻垢与除垢的连续在线操作,与传统阻垢与除垢方法相比,超声波阻垢与除垢技术具有自动化程度高、工作性能可靠、不需要化学试剂、对环境无污染等特点,是一种值得推广的新方法。     

工业锅炉锅内水质处理方法的现状和发展

介绍了工业锅炉锅内水质处理的各种方法和技术以及添加药剂的使用方法,并对工业锅炉锅内水处理技术的未来发展方向作了展望。     

地热流体开发利用中防垢除垢技术研究进展

地热流体结垢是阻碍地热资源稳定、经济和高效开发利用的因素之一。系统总结了中高温地热流体开发利用中防垢除垢技术研究进展。中高温地热田中代表性垢物是钙垢和硅垢,其中钙垢成分以CaCO₃为主,多形成于因压力下降导致CO₂脱气的开采井或者地面设备,硅垢成分以无定型SiO₂为主,多形成于因温度下降导致的溶解度减小的回灌井或者地面设备。实际生产中防垢除垢技术应结合地热流体利用方式进行选择和优化,直接利用方式可考虑采用基于CaCO₃和无定型SiO₂热力学性质的防垢技术;发电方式中钙垢可考虑阻垢剂注入的防垢技术,而硅垢则考虑利用石英和无定型SiO₂溶解度差异、调控温度、pH、无定型Si O₂浓度等防垢技术。     

不同水质稳定剂对凝汽器不锈钢管的缓蚀性能

研究了4种不同水质稳定剂对304不锈钢耐点蚀性能的影响。实验结果显示,在实验用冷却水原水中不锈钢不出现点蚀,但随着原水的浓缩不锈钢出现点蚀,水质分析显示在冷却水浓缩过程中出现钙垢沉积。4种复配稳定剂均可在一定程度上抑制冷却水在浓缩过程中对不锈钢的点蚀,其中在含2、4号稳定剂的冷却水中浓缩倍率在3倍及以下时不锈钢不发生点蚀;在含1号稳定剂冷却水中,浓缩倍率在4倍及以下时不锈钢不出现点蚀;而含3号稳定剂时,不锈钢在浓缩至6倍的冷却水中仍未点蚀。根据某电厂的要求,确定了性价比较高、适合该电厂使用的水质稳定剂。     

铸造缺陷修补机在发动机铸件缺陷焊补方面的应用及分析

通过铸造缺陷修补机在灰铁250、球铁500及铝合金101三种材质试块上焊补效果的显微分析，以及对HT250发动机缸体、删气缸套、ZL101发动机缸体缺陷渗漏的焊补效果检测，说明铸造缺陷修补机在灰铁、球铁、铝合金三种材质上的焊补效果满足性能要求，是一种值得推广的新技术。     

焦化厂实行梯级用水降低水耗的实践

通过对焦化厂所用水水质和不同用水系统工艺特点的分析,制订焦化厂梯级用水制度,降低水耗30％;对水处理设备进行改进,稳定水处理药剂浓度;根据阻垢及缓蚀实验结果,确定适用于高氯离子浓度循环水系统的阻垢缓蚀剂。     

Chemical thermodynamics in geothermal operations

Chemical thermodynamics of geothermal brines are important in every aspect of geothermal development, starting from initial stages of exploration to the final stages of utilization. Yet there are serious gaps in the knowledge of high temperature thermodynamics of aqueous fluids. The critical areas of chemical thermodynamics that need serious evaluation include: (1) chemical and physical characteristics of aqueous solutions at high temperatures, (2) solubility and phase behaviour of numerous inorganic solids in aqueous media at high temperatures, (3) solubility and flash behaviour of gases in equilibrium with aqueous media at high temperatures and (4) cement, metal and other material resistivity to any mechanical and/or chemical degradation in various high temperature aqueous environments. The present paper reviews the status of the various aspects of chemical thermodynamics. The emphasis is placed in reviewing the various methodologies used in predicting scale formation and gas flashing during the production of geothermal brines. Various well-known models used in obtaining the chemical thermodynamic information are also critically reviewed. The general lack of knowledge on the data bases related to solubility of various species in high temperature brine is clearly pointed out. Based on the critical review of chemical thermodynamics of geothermal brines, the following conclusions are made: 1. The basic chemical thermodynamics of aqueous systems at high temperatures are not well known. 2. There is a lack of a thorough and reliable data base related to the phase behaviour of inorganic solids and their solubilities in aqueous media at high temperatures. 3. The solubilities and flash behaviours of gases in equilibrium with aqueous media at high temperatures and high pressures are not well known.     

含硫循环水增效缓蚀阻垢处理工艺及应用

为减少新鲜水用量和排污量．中国石化九江分公司在循环水硫化物浓度偏高的情况下应用了增效缓蚀阻垢处理工艺。应用结果表明,循环水中硫化物浓度在0．1～1．0mg／L的条件下,采用增效缓蚀阻垢处理工艺可使试验试管腐蚀速率由0．134mm／a降至0．062mm／a,试管黏附速率由10．72mg／（cm^2·月）降至0．140mg／（cm^2·月）,缓解了因物料泄漏对设备造成的严重腐蚀。     

利用炼钢工艺处理废塑料的工业试验研究

利用废塑料与铁鳞进行混合,加热成型制成球团,并在80 t转炉生产条件下进行工业试验研究。结果表明:1加入废塑料铁鳞球团后,钢水成分达标,并利于后期脱硫脱磷;2在试验条件下,随着废塑料铁鳞球团加入量增加,渣中的Σw(Fe O)呈上升趋势,有利于快速化渣;3废塑料铁鳞球团能够替代OG泥球团和矿石作为造渣剂使用;41 t废塑料铁鳞球团能够降低钢水温度35~40℃,介于矿石和OG泥球团之间。     

Photoelectrochemical hydrogen production with concentrated natural seawater produced by membrane process

Water shortages are anticipated to occur all over the world and are likely to have a significant effect on the availability of water for processes such as photocatalysis and electrolysis, as well as for drinking and industrial water. To overcome this problem, it has been suggested that seawater could be used as an alternative resource for the various water industries, such as hydrogen production, industrial and drinking water. Seawater contains a large amount of dissolved ion components, thus allowing it to be utilized as an electrolyte in photoelectrochemical system for producing hydrogen. Especially, the concentrated shows higher salinity (total dissolved solids, TDS) than the general seawater fed to the membrane process, because the permeate has a lower salinity and the retentate is more concentrated than the original seawater. For these reasons, the hydrogen evolution rate was investigated in a photoelectrochemical system, including anodized tubular TiO₂ and platinum as the photoanode and cathode, an external bias (solar cell) and the use of various types of seawater prepared by the nanofiltration membrane process as the electrolyte in the photoelectrochemical system.The results showed that the rate of hydrogen evolution obtained using the relatively tight nanofiltration membrane, NF90, operated at 20 MPa in the photoelectrochemical system is ca. 270 μmol/cm² h, showing that the retentate with a higher TDS than the general TDS of seawater acts as a more effective seawater electrolyte for hydrogen production.     

抑尘工作中的问题及对策探讨

抑尘车高喷水雾的抑制道路二次扬尘率约为85％,效果显著。叙述了抑尘车在运行过程中存在的诸如交通拥堵、淋湿部分行人和车辆、发生追尾事故等问题。提出了解决好上述问题措施。     

Enhanced porosity of Ni@Hollow meso-SiO2 catalyst for CO2 reforming of methane

The dry reforming of methane is a potential reaction that converts methane and carbon dioxide to syngas while mitigating the two greenhouse gases. Challenges for this reaction include sintering and severe carbon deposition. This paper reports a post-treatment strategy to develop Ni@hollow meso-SiO₂ (Ni@HMS) catalyst from the existing Ni@SiO₂ core-shell structure by utilizing the mechanism of etching and re-deposition of silica in mild alkaline solution with CTAB as a stabilizer. The varied post-treatment temperature changed the properties of Ni@HMS and demonstrated high catalytic performance compared to Ni@SiO₂. The results from TEM and XPS showed the Ni particles were confined inside the mesoporous SiO₂ shell and inhibit Ni particle mobility. The catalysts exhibited high conversion of methane (>80%) and carbon dioxide (>90%) for 50 h at 800 °C and WHSV of 54 000 mL g_cat^?1h^?1 with high TOF_CH4 of 7.08 s^?1.     

Characterization and PEMFC application of a mesoporous sulfonated silica prepared from two precursors, tetraethoxysilane and phenyltriethoxysilane

In this study, the mesoporous phenyl-silica (PS) is synthesized with tetraethoxysilane (TEOS) and phenyltriethoxysilane (PTES) as the Si-precursors. Then PS is sulfonated by the simple sulfonation with concentrated sulfuric acid to prepare the mesoporous sulfonated-phenyl-silica (SS). The Nafion^®-based nanocomposite membranes, N/PS and N/SS, are successfully prepared with PS and SS silicas, respectively, and used as PEM for preparation of the PEMFC single cells. It is found that compared with the Nafion^® membrane, NRE-212, and N/PSs, the best N/SS, SS1, which contains 3 wt.% of SS1 with about 5.18 wt.% sulfonic acid groups, exhibits more than 2-folds higher water uptake and slightly higher ion-exchange capacity (IEC). The highest proton conductivity of the as-prepared nanocomposite membranes at room temperature is in the same order as that of NRE-212. The power density of the PEMFC single cell fabricated with the best N/SS is 460 mW cm⁻² at 110 °C under the humidified condition, which is approximately 13% and 53% higher than that with the N/PS and NRE-212. Besides, the peak power density obtained at 65 °C under dry condition is 414 mW cm⁻², which is approximately 4 times higher than that of the N/PS.     

等温淬火球铁的生产研究

试生产等温淬火球铁斜楔 ,代替原来的铸钢件。本文就等温淬火球铁中的化学成分、熔化生产、球化和孕育处理、热处理等一些技术问题 ,进行了研究     

Preparation of a new Ti catalyst for improved performance of NaAlH4

Three effective Ti catalysts for NaAlH₄ were made by stoichiometrically reacting TiCl₃ with LiAlH₄ in tetrahydrofuran (THF), NaAlH₄ in THF, and LiAlH₄ in diethyl ether (Et₂O). The solid products produced after drying were named ex situ catalysts and designated respectively as Ti(Li)T, Ti(Na)T and Ti(Li)E. NaAlH₄ was dry doped with 2 mol% of these ex situ catalysts, and for comparison, NaAlH₄ was conventionally wet doped with 2 mol% TiCl₃ in THF that made in situ catalyst (designated as TiCl₃). All four doped samples were dry ball milled, and hydrogenation and dehydrogenation studies were carried out over five cycles. Temperature programmed desorption, constant temperature desorption, and constant temperature cycling curves showed that the effectiveness of these catalysts decreased as Ti(Li)T > Ti(Na)T > TiCl₃ > Ti(Li)E. Ti(Li)T ex situ catalyst, being the best Ti catalyst, markedly decreased the dehydrogenation temperature, improved both the hydrogenation and dehydrogenation kinetics with sustained rates over cycling, and exhibited the least loss of hydrogen storage capacity over cycling. Ti(Li)T ex situ catalyst exhibited properties commensurate with some of the best NaAlH₄ catalysts to date, such as CeCl₃, ScCl₃ and Ti nanocluster. It is easy to make, readily available and relatively inexpensive.