基于CFD分析的呼吸防护面具罩体设计

分析呼吸防护面具研究领域在呼吸阻力方面的研究情况,提出基于计算流体力学分析的呼吸防护面具罩体设计方案,在设计过程中添加以计算流体力学分析为手段的有限元模拟仿真模块。通过ANSYS产品ICEM CFD与CFX对设计模型进行网格划分与流体分析,根据仿真结果对初步设计的模型进行结构优化再设计。     

O3-BAC组合工艺深度净化MBR出水的中试研究

采用臭氧-生物活性炭(O3-BAC)组合工艺对某工业园区再生水厂MBR出水进行了深度净化的中试研究,主要考察了组合工艺各节点对常规指标的处理效果.结果表明,臭氧投加量约3 mg/L(H2O)、臭氧接触塔接触时间为30min、活性炭滤池空床接触时间(BECT)为15 min时,O3-BAC组合工艺能有效去除水中色度、浊度...     

基于MBR出水的纳滤预处理技术优化分析

针对再生水厂膜生物反应器(MBR)出水水质特征,对后续深度处理工艺中与纳滤组合的预处理技术进行筛选.通过对臭氧、活性炭、臭氧-活性炭3种预处理技术对比,分析3种预处理方式对有机物的去除效率及对分子尺寸的影响规律.实验结果表明,3种预处理技术对MBR出水中有机物的平均去除率分别为6.6%、31.7%和36.6%;市政污水...     

利用甘蔗渣制备微生物絮凝剂的预处理方法研究

通过对甘蔗渣进行不同的预处理,确定了提高纤维素酶糖化率和酱油曲霉发酵液絮凝率的方法.利用正交实验对固液比、颗粒粒径、溶剂浓度和预处理时间及其交互作用进行考察,确定较优的工艺方案.结果表明,在相同条件下,碱处理能够有效提高纤维素酶的糖化率,处理后甘蔗渣的酶解液中还原性糖浓度和酱油曲霉发酵液的絮凝率分别为3.46 g/L和...     

石油类污染地下水中挥发性有机物低温生物降解性能的研究

针对地下水石油类污染的问题,从某污染场地土壤中筛选驯化出了适用于处理挥发性有机物的3株低温高效降解菌,并以苯和萘作为特征组分考察了pH、DO、温度、氮磷等因素对降解效果的影响;实验结果表明,在8℃左右的地下环境中,DO和氮磷的含量对污染物的降解影响较大;在pH 7.5、DO＞4 mg/L和投加氮磷的条件下,18 d内降...     

An integrated method for safety pre-warning of complex system

In large-scale and complex industrial systems, unplanned outages and hazardous accidents cause huge economic losses, environmental contamination, and human injuries, due to component degradation, exogenous changes, and operational mistakes. In order to ensure safety and increase operational performance and reliability of complex system, this study proposes an integrated method for safety pre-warning to analyze the current safety state of each component and the whole system indicating hidden hazards and potential consequence, and furthermore predict future degradation trends in the long term.The work presented here describes the rationale and implementation of the integrated method incorporating HAZOP study, degradation process modeling, dynamic Bayesian network construction, condition monitoring, safety assessment and prognosis steps, taking advantage of the priori knowledge of the interactions and dependencies among components and the environment, the relationships between hazard causes and effects, and the use of historical failure data and online real-time data from condition monitoring.The application of the integrated safety pre-warning approach described here to the specific example of the gas turbine compressor system demonstrates how each phase of the presented method contributes to completion of the safety pre-warning system development in a systematic way.     

Characterization of heavy metals in fly ash from municipal solid waste incinerators in Shanghai

This study aims to develop a methodology for analysis of characteristics of heavy metals in MSWI fly ash. It performed analysis of composition of heavy metals, leaching toxicity, leaching behavior as a function of pH, specification distribution and corresponding mineral components of residue derived from each step of the sequential extraction. It is found that content of heavy metals follows the sequence of Zn > Pb > Cu > Cr > As > Ni > Cd approximately Hg in both plants, and that total heavy metals account for less than 1% by mass of fly ash. Major hazardous heavy metals in fly ash are As, Cd, Hg, Pb and Zn, whose leaching ratios exceed the limit value described in hazardous waste identification standard. Measured leaching results of Cu, Pb and Zn are essentially consistent with the simulated results at pH between 0 and 13. Content of calcium-silicates, alumino-silicates and glass phases in residue derived from sequential extraction procedure increases steadily from the first step to the fifth step of the sequential extraction procedure. Cu, As, Cr, Hg, Cd, and Ni, relatively stable under strong basic conditions, can be leached out under strong acidic conditions, while Zn and Pb tend to be leached out under both strong acidic and basic conditions.     

国有石化企业安全管理工作的重心

石化工业由于大量使用可燃、腐蚀、有毒物质，引起的火灾、爆炸及中毒的危险性很大。同时，生产装置大型化、自动化程度越来越高、操作难度越来越大，因此生产装置由于局部小的问题引发连锁反应，形成重、特大恶性事故频率在增加，事故所产生的社会影响在加大，甚至造成国际影响。     

Application of response surface methodology to the treatment landfill leachate in a three-dimensional electrochemical reactor

The influence of different variables on the removal of ammonia nitrogen and COD from landfill leachate was investigated in a three-dimensional electrochemical reactor. Box–Behnken statistical experiment design and the response surface methodology were used to investigate operating condition effects, such as current density, activated carbon to water ratio and the reaction time, on ammonia nitrogen removal efficiency and COD removal efficiency. The positive and negative effects of variables and the interaction between variables on ammonia nitrogen removal and COD removal were determined. The response surface methodology models were derived based on the results and the response surface plots were developed accordingly.     

Quantitative risk analysis of toxic gas release caused poisoning—A CFD and dose–response model combined approach

Some major toxic gas release accidents demonstrate the urgent need of a systematic risk analysis method for individuals exposed to toxic gases. A CFD numerical simulation and dose–response model combined approach has been proposed for quantitative analysis of acute toxic gas exposure threats. This method contains four steps: firstly, set up a CFD model and monitor points; secondly, solve CFD equations and predict the real-time concentration field of toxic gas releases and dispersions; thirdly, calculate the toxic dose according to gas concentration and exposure time; lastly, estimate expected fatalities using dose–response model. A case study of hydrogen sulfide releases from a gas gathering station has been carried out using a three dimension FLUENT model. Acute exposure fatalities have been evaluated firstly with a simplified ideal model which assumes workers stay at original exposure location without moving. Then a comparison has been made with a more realistic model which assumes workers start evacuating according to a prearranged course as soon as hydrogen sulfide detection system alarms. These two models represent the worst and best emergency response effects, respectively, and the analysis results demonstrate significant differences. Results indicate that the CFD and dose–response combined approach is a good way for estimating fatalities of individuals exposed to accidental toxic gas releases.