Electrochemical degradation of petroleum hydrocarbons (PAHS) from synthetic aqueous solutions

Water separated from crude oil and wastewater discharge from petroleum oil refineries contains significant quantity of dissolved hydrocarbons. Polycyclic aromatic hydrocarbons (PAHs) are major toxicants in wastewater of refineries. It is difficult to treat wastewater containing PAHs due to their recalcitrant property and low solubility. Conventional techniques for the treatment of wastewater are still a concern of toxicity. Electrochemical oxidation process has been found to be a favorable for treating wastewater. Electrodes with high stability and electrocatalytic activity are important factors for a successful electrochemical oxidation of toxic organics in wastewater. In this study titanium anodes were coated with tin, antimony and iridium oxide mixture from their respective salts by thermal decomposition method. FESEM and XRD used for surface characterization of Ti/SnO₂–Sb₂O₅–IrO₂ anode. Quantification of PAHs was done using GC–MS. Results confirm the presence of respective oxides on anode surface. Their electrocatalytic capability was tested for degradation of 16 priority PAHs in aqueous solution. Results reveal the complete degradation of naphthalene, acenaphthylene, acenaphthene and fluorene without using NaCl electrolyte. While in the presence of NaCl naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene were completely removed. About 98% of total PAHs removal was found at all initial pH values 3, 6, and 9 in the presence of electrolyte. Current study will be helpful in improving quality of petroleum industry wastewater containing PAHs.     

Zinc-Modified ZSM-5 Nanozeolites Synthesized by the Seed-Induced Method: Interrelation of Their Textural,Acidic, and Catalytic Properties in DME Conversion to Hydrocarbons

The effect of the method of introduction of zinc cations and the zinc content in a nanocrystalline zeolite of the ZSM-5 type on the physicochemical and catalytic properties of the material in DME conversion to a mixture of liquid synthetic hydrocarbons has been studied. Zinc is introduced into the catalysts both during the zeolite synthesis and the ion exchange (Zn _n Al _m NZ5 and ZnNZ5, respectively). The use of nanocrystalline Zn _n Al _m NZ5 zeolites provides the formation of a mixture of liquid hydrocarbons with a high selectivity of no less than 90%; the liquid hydrocarbons contain more than 70% of isoparaffins and a small amount of aromatic compounds. An increase in the zinc loading of the Zn _n Al _m NZ5 zeolite from 0.9 to ~3% leads to an increase in the methanol content in the aqueous phase of the liquid product, an increase in the selectivity for liquid hydrocarbons, and a slight increase in the concentration of aromatic and unsaturated hydrocarbons in the mixture. In the presence of the ZnNZ5/Al₂O₃ catalyst with Zn introduced by ion exchange, the methanol content in the aqueous phase and the aromatics content in the liquid hydrocarbon mixture are significantly higher. The Zn _n Al _m NZ5 nanozeolites are characterized by a more developed external surface, a higher concentration of mesopores, and higher acidity.     

特殊形状饮料瓶专用树脂的开发与应用

确定了特殊形状饮料瓶专用树脂高密度聚乙烯5500 B的物性指标和生产工艺条件,并进行了工业化生产及标定。结果表明,5500 B的熔体流动速率为0.60~0.80 g/10 min,密度为0.952~0.958 g/cm~3,耐环境应力开裂时间大于20 h;正已烷提取物≤2.0%、干燥失重≤0.15%、灼烧残渣≤0.2%,符合国家标准要求,产品力学性能和卫生性能均达到设计指标,所制饮料瓶制品满足用户的需求。     

催化裂化装置前置烧焦罐提高烧焦强度实验与研究

长岭石化公司通过对烧焦罐改造前后对比分析得出造成尾燃现象的根本原因是烧焦罐底部烧焦不均,再生系统烧焦强度下降,再生器顶超温、尾燃。通过烧焦罐底部注入燃料油实验,分析了喷燃料油对烧焦罐烧焦强度、再生剂性质、产品分布的影响。提出了喷燃料油实验可行性研究结论,为指导装置生产提供了依据。