适用于深井钻井的KCl/聚磺水基钻井液体系研究

针对深井钻井,从优选处理剂入手,解决钻井液高温稳定性,泥页岩水化,储层保护等方面的问题,研制适用于深井钻井的KCl/聚磺水基钻井液体系。并对该体系的高温稳定性、抗污染性、防塌抑制性和储层保护效果进行室内评价。最终优选出的钻井液配方高温高压流变性合理,抗污染性和防塌抑制性强并成功应用于东部某油田的深井钻井。     

LiF-KCl熔盐溶液的径向分布函数SCIEI

本文利用X射线散射技术测定和Monte Carlo计算机模拟计算,获得了LiF-KCl熔体的径向分布函数。实验发现,在互易系LiF-KCl熔体中,小离子Li^+与F^-更易形成结合较为紧密的集团,而大离子K^+与Cl^-的结合相对较为松地,即出现“大大小小”效应。     

High temperature interaction of Al/Si-modified Fe-Cr alloys with KCl

The corrosion behaviour of pure iron, pure chromium, and aluminium/silicon alloyed Fe-Cr materials was investigated at 650 °C in air accompanied by gaseous or solid KCl salt. The corrosion rates of these materials with KCl salt are high and they are strongly affected by the salt amount, the types of the alloying elements and the concentration of chromium. The dominant degradation mechanism for the chromia-forming alloys by KCl attack is the preferential formation of potassium chromate over the conventionally protective chromia, characterized by typical features of bubbles, cracks, volatility and severe spallation for the corrosion products. A detrimental effect of chromium is confirmed. Al-alloying addition to Fe-Cr alloys is beneficial by enhancing the corrosion resistance. Silicon is more effective in promoting the corrosion resistance of Fe-Cr alloys by forming a stable and dense oxide layer in the inner zone which suppresses the rapid growth of iron oxides.     

The Tribological Properties of Monolayer KCl Films on Iron in Ultrahigh Vacuum: Modeling the Extreme-Pressure Lubricating Interface

The friction coefficients of thin KCl films deposited onto clean iron in ultrahigh vacuum are measured using a tungsten carbide tip. A rapid decrease is found in the friction coefficient from 2 for clean iron to 0.27 ± 0.03 after the deposition of 40 Å of KCl. Based on previous contact resistance measurements, this was proposed to be due to the completion of the first layer of KCl. The first-layer KCl coverage was measured by adsorbing deuterium onto an iron surface partially covered by KCl, where deuterium selectively adsorbs onto the iron. This revealed that the first monolayer is complete after the deposition of 40 Å of KCl and that the first-layer KCl film coverage _KCl ⁽¹⁾ is given by _KCl ⁽¹⁾ = 1 - exp(-0.39±0.02t), where t is the film thickness. XPS data suggest that heating a KCl film to 550 K causes it to wet the surface. This leads to decreases in the friction coefficients for thin KCl films in accord with the idea that friction is reduced by the first monolayer of KCl on iron. Temperature-programmed desorption data indicate that KCl in the first monolayer is 5 kJ/mol more stable than the multilayer consistent with the wetting behavior. Finally, the kinetic data are analyzed to suggest that the first-layer film is 2.6 Å thick.     

Fabrication and Corrosion Behaviour of Platinum-Coated Titanium Electrodes from Low Temperature Molten Salt Electrolytes

The development of corrosion-resistant platinum coated titanium (Pt/Ti) electrodes for seawater electrolysis in the production of sodium hypochlorite is an important requirement. In this study a new ternary low temperature molten salt (LTMS) LiCl—NaCl—KCl system was chosen as the electrolyte. The direct current method of four Pt electrodes combined with a computer program was employed to measure the relationship between conductivity and temperature of the chosen electrolyte at various PtCl₂ concentrations. The pulse current technique was used for fabrication of Pt/Ti electrodes from the chosen LTMS electrolyte at the temperature and PtCl₂ concentration where the conductivity of the LTMS system was highest by changing the duty-cycle and plating current density. The morphology and composition of the Pt-coated layer was examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Tafel plots, anodic polarization curves and electrochemical impedance spectroscopy (EIS) were employed to evaluate the corrosion behaviour of the Pt/Ti electrodes. The best quality Pt-coated electrodes were obtained from the pulse plating condition of T _on:T _off= 3:1 with a current density (i _plat) of 127.5 mA cm^–2. These had a higher Pt content, nobler corrosion potential (E _corr), lower corrosion current density (i _corr), lower passive current density (i _pass) and higher impedance. Furthermore, AFM demonstrated that the best quality Pt/Ti electrode had the lowest surface roughness (R _a) with the finest grain size.     

Detection of gaseous species during KCl-induced high-temperature corrosion by the means of CPFAAS and CI-APi-TOF

Two different analytical approaches—collinear photofragmentation and atomic absorption spectroscopy (CPFAAS) and chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF)—were applied to detect and identify the online gaseous KOH and HCl formed in the addressed high-temperature reactions. Samples of pure KCl, KCl+Cr, KCl+Fe, and KCl+316 L were studied at 550°C under dry and humid conditions with varying oxygen concentrations. The goal was to shed more light on the gas-phase chemistry during KCl-induced corrosion under conditions relevant to biomass combustion. CI-APi-TOF proved to be a valuable tool for high-temperature corrosion studies: HCl was identified to have formed during the reactions under humid conditions. On the contrary, despite the known sensitivity of CPFAAS, the formation of KOH could not be verified in any of the performed measurements.     

The effect of sodium reduction with and without potassium chloride on the survival of Listeria monocytogenes in Cheddar cheese

Sodium chloride (NaCl) in cheese contributes to flavor and texture directly and by its effect on microbial and enzymatic activity. The salt-to-moisture ratio (S/M) is used to gauge if conditions for producing good-quality cheese have been met. Reductions in salt that deviate from the ideal S/M range could result in changing culture acidification profiles during cheese making. Lactococcus lactis ssp. lactis or Lc. lactis ssp. cremoris are both used as cultures in Cheddar cheese manufacture, but Lc. lactis ssp. lactis has a higher salt and pH tolerance than Lc. lactis ssp. cremoris. Both salt and pH are used to control growth and survival of Listeria monocytogenes and salts such as KCl are commonly used to replace the effects of NaCl in food when NaCl is reduced. The objectives of this project were to determine the effects of sodium reduction, KCl use, and the subspecies of Lc. lactis used on L. monocytogenes survival in stirred-curd Cheddar cheese. Cheese was manufactured with either Lc. lactis ssp. lactis or Lc. lactis ssp. cremoris. At the salting step, curd was divided and salted with a concentration targeted to produce a final cheese with 600 mg of sodium/100 g (control), 25% reduced sodium (450 mg of sodium/100 g; both with and without KCl), and low sodium (53% sodium reduction or 280 mg of sodium/100 g; both with and without KCl). Potassium chloride was added on a molar equivalent to the NaCl it replaced to maintain an equivalent S/M. Cheese was inoculated with a 5-strain cocktail of L. monocytogenes at different times during aging to simulate postprocessing contamination, and counts were monitored over 27 or 50 d, depending on incubation temperature (12 or 5°C, respectively). In cheese inoculated with 4 log₁₀ cfu of L. monocytogenes/g 2 wk after manufacture, viable counts declined by more than 3 log₁₀ cfu/g in all treatments over 60 d. When inoculated with 5 log₁₀ cfu/g at 3 mo of cheese age, L. monocytogenes counts in Cheddar cheese were also reduced during storage, but by less than 1.5 log₁₀ cfu/g after 50 d. However, cheese with a 50% reduction in sodium without KCl had higher counts than full-sodium cheese at the end of 50 d of incubation at 4°C when inoculated at 3 mo. When inoculated at 8 mo postmanufacture, this trend was only observed in 50% reduced sodium with KCl, for cheese manufactured with both cultures. This enhanced survival for 50% reduced-sodium cheese was not seen when a higher incubation temperature (12°C) was used when cheese was inoculated at 3 mo of age and monitored for 27 d (no difference in treatments was observed at this incubation temperature). In the event of postprocessing contamination during later stages of ripening, L. monocytogenes was capable of survival in Cheddar cheese regardless of which culture was used, whether or not sodium had been reduced by as much as 50% from standard concentrations, or if KCl had been added to maintain the effective S/M of full-sodium Cheddar cheese.     

盐对颗粒态抗性淀粉形成的影响

抗性淀粉是一种极其重要的功能性食品添加剂。颗粒态抗性淀粉具有不同于传统抗性淀粉的性质,对其研究具有重要意义。文中考察了盐(NaCl、KCl和CaCl2)对颗粒态抗性淀粉形成的影响,得出NaCl和KCl的最适添加量分别为20%和12%,而CaCl2的添加对抗性淀粉形成不利。     

KCl替代NaCl对东北酸菜细菌菌群多样性的影响

该研究采用KCl替代NaCl自然发酵制备东北酸菜,采用高通量测序技术对酸菜样品的细菌菌群多样性进行分析,同时采用9分制评分法进行感官品质评价,考察不同KCl替代量（0、25%、50%、75%、100%）对东北酸菜细菌菌群多样性及感官品质的影响。结果表明,在所有酸菜样品中共检出454个菌属,其中,KCl替代量为50%时菌属种类最少（222）,KCl替代量为100%时菌属种类最多（252）。KCl替代量对于酸菜的细菌菌群种类与相对丰度均有显著影响。KCl替代量为0与100%的样品与其他样品之间的物种差异性较大,KCl替代量在25%～75%之间的样品物种差异性较小。当KCl替代量为50%时,酸菜的苦味、整体评价发生显著变化。综上,KCl替代Na Cl对酸菜中的细菌多样性会产生显著影响,当替代量>50%时会对酸菜的感官品质产生不利的影响。     

缅甸Y-1井钻井液的研究与应用

通过聚合物体系直接转化得到KCl／PHPA钻井液体系,使用KCl、PHPA控制泥浆的抑制包被性能,使用沥青类、树脂类处理剂增强泥浆的封堵防塌性能,维护适当的流变性能并且严格控制失水。将KCI／PHPA钻井液体系用于缅甸Y-1井的现场钻探,结果表明,该体系具有抑制性好、防塌能力强、滤失量低、润滑性能好、性能易于调控等特性,有效地克服了凝灰岩地层破碎掉块、坍塌、岩屑携带等问题。钻井过程中起下钻畅通,下套管顺利,井径规则,满足安全钻井的要求。