Environmental assessment of ester-based lubricants after application

GOAL, SCOPE AND BACKGROUND: Lubricants based on renewable resources are an environmentally friendly alternative to petrochemical products due to their better ecotoxicological performance and their excellent biodegradability. To improve the technical performance of lubricants, and to reduce friction and wear, the use of additives is nowadays obligatory. The collaborative research center SFB 442 aims at developing environmentally acceptable lubricants that facilitate the avoidance of these additives by transferring their function to suitable coatings. For a complete assessment of the ecological performance of these newly developed lubricants, the whole life cycle including production, application as well as disposal and fate in the environment is studied. In the following study the focus was on the application and its influence on the environmental behavior of the lubricant. The application of lubricants leads, among other things, to the intake of metals due to abrasion from tools, work pieces or mechanical components. Previous examinations indicated a possible influence of metals on the toxicity of eluates prepared from used lubricants (Erlenkaemper et al. 2005). To clarify if the apparent toxicity of used lubricants solely results from the intake of metals, the extractability of these metals from the oil matrix is determined. By combining chemical analyses with bioassays, the bioavailability of metals that are present in the extract is estimated. To further investigate the relevance of metals on toxicity, toxic units (TU) were calculated and related to the results of the bioassays. Interactions between the metals were investigated with aqueous mixtures of metal chlorides and calculations based on the concept of concentration addition and independent action. METHODS: A lubricant mixture was applied to a tribological test bench that simulates real conditions of use and extremely short time load, respectively. Samples were taken at particular times, water soluble fractions (WSF) of these fluids were prepared and dilution series were investigated in several bioassays. Concentration of metals and total organic carbon (TOC) were determined in the eluates. TUs were calculated according to Sprague (1970) and mixture toxicity was calculated according to the concept of concentration addition (Loewe and Muischnek 1926) and independent action (Bliss 1939). RESULTS: Analyses of the metal content of the lubricant and the eluates clearly revealed the availability of the metals in the aqueous extracts. Especially copper, zinc, nickel and chromium were found and their concentrations increased during the time of use. The water extractable fraction, e.g., of copper, rose from 8.8% to 45.3% of the total content in the lubricant after 33.5 hours of use. Tests performed with the algal growth inhibition assay and the luminescence inhibition assay revealed the uptake or absorption by the organisms and, thus, the bioavailability of the metals. The calculation of TUs partly indicated a possible influence of the metals on ecotoxicity of the eluates. Copper reached concentrations equal to or higher than the EC50 value of copper chloride in the growth inhibition assays with algae and Ps. putida as well in the immobilization assay with daphnids. TUs for copper are also larger than 1 for the algal growth inhibition assay. The EL50 values indicated that the luminescence inhibition assay was the most sensitive test system, with values between 4.7% and 9.6%. While the toxicity towards algae and V. fischeri in the growth inhibition assay decreased until both organisms were no longer influenced by the exposure, the EL50 values for the D. magna immobilization assay and the Ps. putida growth inhibition assay decreased with the progressing use of the lubricant. The tested metal salt mixtures showed that Ps. putida, algae and daphnids are the most sensitive organisms with EC50 values below 1 mg/l. DISCUSSION: Although the intake of metals mainly occurred via abrasion of particles, the results revealed the availability of these metals in water. The availability varied for each of the four metals. For both the algal growth inhibition assay and the luminescence inhibition assay, an uptake or absorption of the metals could be demonstrated. The calculated TUs indicated an effect in some bioassays that was not verified in the test itself. The influence of copper on V. fischeri, for example, was not confirmed while the EL50 values for the daphnid bioassay decreased, meaning that the eluates became more toxic with progressing use of the lubricant. The calculations of mixture toxicity based on the concept of concentration addition demonstrated good correlations with the tested metal mixtures, but also a different sensitivity of the organisms. CONCLUSIONS: The results presented here reveal the availability of those metals in water that were taken in during the use of the lubricant in a tribological test bench and, thus, have the possibility of interacting with the organisms. The availability of the metals in the bioassays was proven by chemical analyses. The calculation of TUs and the corresponding EL50 values, however, indicate different availabilities of the metals. The results of the metal salt mixtures show good correlations with calculations of mixture toxicity based on concentration addition. Moreover, the varying sensitivity of the organisms when exposed to eluates or metal mixtures indicates a different bioavailability of the metals and/or the presence of other compounds that exert toxic action. RECOMMENDATIONS AND PERSPECTIVES: For further investigations, the organic oil matrix and its influence on the toxicity have to be taken into account. The toxicity of the eluates may not only be due to metals; additional effects could arise from changes in the lubricant itself.     

石化废水挥发性有机物逸散量的估算方法

总结了实测法、物料衡算法、模型法、排放系数法、工程估算法等国内外石化废水挥发性有机物(VOCs)逸散量估算方法的主要特点及适用范围。应用排放系数法和实测法估算国内某石化厂废水收集处理系统VOCs逸散量为354.26 t/a。根据估算方法的实际应用研究,建议物料衡算法中废水油相VOCs逸散可结合油相敞口面积和油相性质,提供废水油相的排放系数;应用Water 9软件估算含油膜废水设施逸散量时,应单独估算油膜VOCs逸散量;建议排放系数法中废水收集系统排水口、检查井未密闭VOCs排放系数均确定为0.032 kg/h(每个逸散源),废水处理系统油水分离器、气浮装置按进水中石油类浓度的大小,分别提供VOCs排放系数。     

炼油装置防治腐蚀存在问题及建议

介绍了劣质原油加工技术现状及发展趋势,以国内炼油企业的腐蚀案例,分析了炼油装置防治腐蚀存在的问题,为今后的工作提出了建议。     

保护层分析（LOPA）在炼化生产中的应用

介绍了目前国际通行的可以有效评估过程危险的保护层分析方法,结合其在炼化生产中某装置的具体运用．来说明保护层分析方法的作用.     

石化装置长周期安全运行风险分析和对策

随着国际竞争的激烈,石化生产装置的长周期运行成为我国石化企业的降本增效的主要手段。如何保证本质安全成为长周期运行的难题。本文以延迟焦化装置为例,主要从工艺原理、工艺原则流程和物料性质等方面进行了系统的风险分析,对设备利用英国TISCHUK公司的T-OCA软件进行RBI(Risk-based Inspection,即RBI)评估,确定了装置长周期运行存在的薄弱环节,并提出了控制措施。实践证明,该套方法对我国石化生产装置的长周期安全运行提供了科学的技术支持。     

微电解反应器应用于石油炼厂污水回用的中试研究

对石油炼厂废水回用进行了 10m3 h并联微电解工艺的中试现场实验研究。检验了微电解设备的性能 ,对出水的防腐指标进行了挂片腐蚀实验。结合电化学原理对实验数据进行了分析。中试工艺的CODCr、石油、悬浮物等的去除率均达到 70 %以上 ,体现了良好的处理效果     

絮凝磁分离技术处理环烷酸钠废水的研究

环烷酸钠是导致炼油废水不能达标排放的主要原因,文章采用絮凝磁分离技术处理环烷酸钠废水,研究各因素对实验结果的影响,确定最佳处理条件,并对实际废水进行了实验研究,结果表明该技术可有效去除炼油废水中的CODcr。     

咪唑类季铵盐阳离子絮凝剂的制备及其在炼油厂废水中的应用

为提高环氧氯丙烷胺类絮凝剂的絮凝性能,以2-甲基咪唑为交联剂,以环氧氯丙烷、二甲胺为原料,制备了新型季铵盐阳离子絮凝剂——MZO,并对其进行红外、核磁表征. 采用MZO对抚顺炼油厂废水进行絮凝除浊试验,并与其他6种改性絮凝剂〔交联剂分别为HMTA(六次甲基四胺)、DET(二乙烯三胺)、TER(三乙烯四胺)、ED(乙二胺)、TE(三乙胺)、DAA(二烯丙基胺)〕进行了对比. 通过单因素试验研究MZO投加量、絮凝温度及其与PFC(聚合氯化铁)复配使用等因素对絮凝性能的影响,通过正交试验确定了其最佳使用条件. 结果表明:①MZO的阳离子度为41.1%,并非最高,但MZO对炼油废水的除浊率能达到98.8%,比其他6种改性絮凝剂提高了1.2%~20.0%不等;②单因素试验确定MZO的最佳絮凝温度为60 ℃,最佳投加量为30 mg/L,MZO与PFC的最佳复配比(质量比)为1∶40;③结合正交试验结果、生产及经济因素确定其最佳使用条件:絮凝温度为55 ℃,投加量为25 mg/L,复配比(质量比)为1∶20,在此条件下,复配后絮凝剂的除浊率达到98.2%.      

A comprehensive evaluation of re-circulated bio-filter as a pretreatment process for petroleum refinery wastewater

Conventional biological treatment process is not very efficient for the treatment of petroleum refinery wastewater (PRW) that contains high-concentration of organic contaminants. Prior to biological treatment, an additional pretreatment process for PRW is required for the effluent to meet the discharge standards. While re-circulated bio-filter (RBF) has been applied as a pretreatment process in several PRW treatment plants, its effects have not been comprehensively evaluated. In this study, the parameters of operation, the changes in pollution indexes and contaminant composition in an engineered RBF have been investigated. We found that mainly highly active de-carbonization bacteria were present in the RBF, while no nitrification bacteria were found in the RBF. This indicated the absence of nitrification in this process. The biodegradable organic contaminants were susceptible to degradation by RBF, which decreased the Biological Oxygen Demand (BOD₅) by 83.64% and the Chemical Oxygen Demand (COD_Cr) by 54.63%. Consequently, the alkalinity and pH value of RBF effluent significantly increased, which was unfavorable for the control of operating parameters in subsequent biological treatment. Along with the decrease of COD_Cr, the RBF effluent exhibited a reduction in biodegradability. 834 kinds of recalcitrant polar organic contaminants remained in the effluent; most of the contaminant molecules having complex structures of aromatic, polycyclic and heterocyclic rings. The results of this study showed that RBF could efficiently treat PRW for biodegradable organic contaminants removal; however, it is difficult to treat bio-refractory organic contaminants, which was unfavorable for the subsequent biological treatment process operation. An improved process might provide overall guarantees for the PRW treatment.     

固定床三维电极反应器深度处理炼油废水

以不锈钢板为阴阳主电极,以柱状活性炭为感应粒子电极,构建固定床三维电极反应器, 并用其深度处理炼油废水。考察了施加电压、水力停留时间、废水pH和曝气量对COD去除效果的影响。实验结果表明,在施加电压10 V、水力停留时间60 min、废水pH=7.0、曝气量120 L/h的优化工艺条件下,处理后出水的COD=27.1 mg/L,满足“超滤—反渗透”单元对进水COD的要求（COD<30.0 mg/L）。