用循环曝气生物滤池工艺处理炼油碱渣废水

采用新型的两级循环曝气生物滤池工艺,对稀释中和后的炼油碱渣废水进行生物处理工业试验。研究了溶解氧质量浓度、水力停留时间、营养物质、pH值、温度和反冲洗周期等因素对碱渣废水生物处理效果的影响。在适宜的操作条件下,炼油碱渣废水经两级生物处理后,COD、硫化物、挥发酚和石油类平均去除率分别达到89.3 %、99.8 %、93.6 %和85.7 %,其中COD和硫化物的平均去除负荷分别达到8.37 kg·m^-3·d^-1和4.44 kg·m^-3·d^-1。循环曝气生物滤池是一种高负荷、高效率、反冲洗周期长和低成本的炼油碱渣废水处理方法,具有良好的应用前景。     

炼油废催化剂生物淋滤脱金属研究进展

绿色低能耗的炼油废催化剂生物淋滤技术已受到广泛关注。本文从炼油废催化剂金属含量及赋存特征、生物淋滤微生物种类、金属浸取效率、生物淋滤过程影响因素和淋滤动力学等角度综述了相关研究成果,并对研究现状和发展前景进行了简要分析。硫酸杆菌、黑曲霉菌、简青霉菌是最常见的废催化剂生物淋滤菌种;生物淋滤作用下加氢废催化剂金属浸取效率较高,流化催化裂化（FCC）废催化剂的金属较难浸取;温度、固液比、废催化剂粒径是影响炼油废催化剂生物淋滤过程的主要因素;化学反应动力学和膜扩散动力学是研究中广泛应用的动力学模型。目前关于生物淋滤处理炼油废催化剂金属的研究仍处于实验室研究阶段,尚未开展小试、中试或工业化应用的相关研究。     

Separation and recovery of vanadium from leached solution of spent residuehydrodesulfurization (RHDS) catalyst using solvent extraction

Leached solution, generated by oxalic acid washing of spent residue hydrodesulfurization (RHDS) catalyst, was used for separation and recovery of vanadium. First of all, solvent extraction, using mixture of 20% (v/v) Alamine-336 and 5% (v/v) tri-butyl phosphate (TBP) as a phase modifier, was conducted to extract molybdenum completely at pH 0.50. Then molybdenum-free solution was used for vanadium extraction at pH 1.25 with 20% Alamine-336 and 5% TBP. Stripping of vanadium from loaded organic solution was performed with 1.5 M H₂SO₄ at O/A phase ratio of 5:1 where more than 99% of vanadium was stripped in two stages. The stripped vanadium solution was further processed by precipitating with ammonium hydroxide to recover ammonium-meta-vanadate which was calcined to obtain vanadium pentoxide. Finally a conceptual process was established for recovery of high purity vanadium pentoxide from oxalic acid leached solution of spent residue hydrodesulfurization (RHDS) catalyst.     

Optimization of recovery of esterase from Serratia marcescens using combination of the solvent impregnated resin and aqueous two-phase extraction techniques

ABSTRACT

The performance of tunable aqueous polymer phase impregnated resins (TAPPIR) which is the combination of the solvent impregnated resin principle and an aqueous two-phase system for the separation of esterase from Serratia marcescens was evaluated in this study. Different molecular weight of polyethylene glycol (PEG) (2000, 4000 and 6000) at concentration ranging from 5% to 20% (w/w) and potassium citrate were used to construct the aqueous phase in TAPPIR technology. Optimum composition of PEG and salt for esterase partitioning was determined using response surface methodology. The optimum condition for the purification of esterase was impregnation of 25% (w/w) of PEG 2000 into 4 mm porous glass beads and extraction of esterase using 15% (w/w) potassium citrate at pH 8 containing 12% (w/w) crude loading with the addition of 4% (w/w) NaCl. Esterase from S. marcescens was successfully purified by the TAPPIR technology up to 5.32 of purification factor with a yield of 75.98%.     

Simple and efficient method for the oxidation of sulfides to sulfones using hydrogen peroxide and a Mo(VI) based catalyst

A simple and efficient method for the oxidation of sulfides to sulfones at room temperature using ammonium heptamolybdate and 30% H₂O₂ is developed. The reactions provide excellent yields within short time, also sensitive functional groups such as allyl, vinyl, propargyl, alcohol, ketone, ester, pyridine and nitrile are found to be tolerated.     

Computer simulation of flow‐sheets for the solvent extraction of uranium: a new route to delay the effect of chemical degradation of the organic phase during uranium recovery from acidic sulfate media

BACKGROUND: The extractants used in solvent extraction processes undergo degradation under thermal, chemical and radiolytical stresses. In the case of uranium plants, tri‐n‐octylamine, used as an extractant, slowly degrades into di‐n‐octylamine. Such degradation causes a gradual depletion of the uranium extraction isotherms and as a result, of the efficiency of uranium recovery from feed solutions. The present work highlights a new route to delay this depletion of the extraction efficiency, merely by optimizing the flow‐sheets involved in the process. Five flow‐sheets have been compared for uranium recovery from acidic sulfate media by a solution of 0.146 mol L⁻¹ tri‐n‐octylamine in kerosene modified with 5% w/w 1‐tridecanol and stripping with a 199 g L⁻¹ Na₂CO₃ solution. These five flow‐sheets include the classical counter‐current flow‐sheet with four mixers–settlers in extraction and three mixers–settlers in stripping and four unusual combined solvent extraction flow‐sheets with two independent extraction stripping loops and with one or two feed inlets. RESULTS: Computer simulation supplied evidence of the strong influence of the studied flow‐sheets on the sturdiness of the process. More precisely, the unusual combined solvent extraction flow‐sheets appeared to be significantly more efficient than the classical counter‐current one and it is shown that an advantage of this can be to delay the negative impact of gradual degradation of tri‐n‐octylamine on uranium recovery efficiency from acidic sulfate media. CONCLUSION: The replacement of classical counter‐current flow‐sheets with a unique extraction‐stripping loop in unusual combined flow‐sheets with two or more independent extraction‐stripping loops and with one or more feed inlets is a fruitful approach to delay the periodic addition of fresh tri‐n‐octylamine necessary for counter‐balancing the progressive degradation of the extraction solvent and, as a result, to delay the gradual depletion of the efficiency of uranium recovery. Copyright © 2009 Society of Chemical Industry