液化气球罐区消防演练过程问题分析及对策

对液化气球罐区泄漏消防演练过程存在的问题进行了分析,提出了整改措施和建议.     

An innovative three-dimensional approach for the simulation of pressure vessels exposed to fire

The present study introduces an innovative approach to the detailed simulation of the pressure build-up in equipment containing saturated liquids when exposed to fire. The approach is based on the adoption of a fully three-dimensional (3D) computational fluid dynamics (CFD) model of the inner fluid. Experimental data gathered from literature studies were used to validate the model considering vessels of several scales and geometries exposed to a full engulfing pool fire. The comparison between the results of the 3D CFD model developed and those of two-dimensional (2D) literature models was also carried out. This enabled deriving precise indications on the selection of the most suitable approach based on the type of accidental scenario to reproduce, confirming 2D models as sound and reliable tools to model the fluid behaviour when homogeneous heat exposure conditions are present. On the other side, limitations of 2D approaches in capturing edge effects on i) temperature profiles, ii) recirculation patterns, and iii) energy accumulation in the vessel lading during fire exposure were identified and discussed. The results obtained represent a valuable source of information to support risk management and emergency response planning.     

复杂海面电磁环境下舰艇的气象保障问题研究

从舰艇气象信息的获取和传输两个方面,分析了复杂海面电磁环境对舰艇气象装备和气象保障的影响。提出了在复杂海面电磁环境下,采用完善气象保障体系、加强手段创新、改进装备性能、加强业务训练等措施来提高舰艇气象保障能力。     

浅谈压力容器制造过程中的材料监检

加强制造过程中对材料的质量控制与监督检验,确保材料选用得当、材料质量过关,是保证压力容器产品质量的前提条件。本文以钢制压力容器为例,结合相关规范、标准,从材料质量证明书、材料标准、熔炼方法、化学分析、材料复验、材料代用等角度阐述了压力容器制造监检过程中的些许案例与经验。     

脱硫灰-石灰石湿法脱硫石膏中杂质悬浮分离实验

根据脱硫灰及石膏的特性,在无挡板平底圆筒搅拌槽内,对脱硫石膏中的杂质进行完全离底悬浮分离实验,研究结果表明,完全离底悬浮搅拌时,悬浮高度比越低,越有利于杂质分离。对于直径D≥24cm的搅拌槽,当桨叶离底高度cb=4cm,桨径槽比d／D=0．65,杂质分离效率叼最高,约82％;当直径D=20cm时,杂质分离效率η随d／D的增大而增大,桨叶离底间距减小,杂质分离效率受d／D影响程度减小;当桨叶离底高度cb=4cm时,随着搅拌槽直径D的增大,杂质分离效率总体呈现增大趋势,降低桨叶离底高度cb杂质分离效率变化较大;进行完全离底悬浮分离后,石膏纯度提高。     

Atmospheric deposition of PCDD/Fs measured via automated and traditional samplers in Northern Taiwan

Most polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the atmosphere are bound to particles which are suspended in the atmosphere, and eventually settle on soil, vegetation, water bodies or other receptors in the environment. Monitoring atmospheric deposition fluxes (dry/wet) is important in tracing the environmental fate and behavior of PCDD/Fs. PCDD/F depositions were collected via an automated PCDD/F ambient sampler and traditional cylindrical vessels, respectively, from April 2007 to February 2008. The automated PCDD/F ambient sampler used in this study can prevent both re-suspension and photo degradation of the PCDD/Fs collected and effectively separates the PCDD/F samples into dry and wet contributions. The results indicated that the ambient PCDD/F concentrations collected using the PS-1 sampler ranged from 0.02 pg I-TEQ/m³ to 0.16 pg I-TEQ/m³ in Northern Taiwan. The results also indicated that the PCDD/F deposition flux collected using the automated PCDD/F sampler (17.5 pg I-TEQ/m² d to 25.8 pg I-TEQ/m² d) was significantly higher than that sampled with the cylindrical vessels (2.0 pg I-TEQ/m² d to 9.9 pg I-TEQ/m² d). The difference was attributed to the fact that part of the PCDD/F depositions collected using the traditional cylindrical vessels had undergone photo degradation and evaporation. In addition, the wet deposition flux of PCDD/Fs (39.4 pg I-TEQ/m² rainy day to 228 pg I-TEQ/m² rainy day) observed in this study was significantly higher than the dry deposition flux (12.3 pg I-TEQ/m² sunny day to 16.7 pg I-TEQ/m² sunny day). These results demonstrated that wet deposition is the major PCDD/F removal mechanism in the atmosphere.     

垃圾渗滤液生物处理出水的深度处理组合工艺

采用"混凝-电解氧化-完全混合式活性污泥法(CSTR)"组合工艺深度处理垃圾渗滤液生物处理出水。探索了工艺的组合及各种工艺操作条件对垃圾渗滤液深度处理效果的影响,并对其影响机理进行了初步探讨。结果表明,以PAC为混凝剂时,在pH和药剂(有效成分)投加量分别为6.0和600 mg/L条件下,渗滤液COD去除率达到50%,有效降低了难溶惰性COD含量,缩短了后续电化学处置时间。混凝工艺后,采用电化学工艺处理,在最优工艺条件下:pH为6.0、电流I为1.2 A(电流密度为18.18 mA/cm2)、Cl-投加量为1 000 mg/L、极板距离为2 cm,电解30 min渗滤液COD去除率达到36%,同时,难降解有毒物含量明显降低,渗滤液可生化性TbOD/COD由10%提升至最大值64%。最后采用CSTR处理渗滤液电解出水,系统出水COD、氨氮和色度分别为100~150 mg/L、7~13 mg/L和25倍,为反渗透(RO)工序提供了良好的水质条件。     

Long-term thermophilic mono-digestion of rendering wastes and co-digestion with potato pulp

In this study, mono-digestion of rendering wastes and co-digestion of rendering wastes with potato pulp were studied for the first time in continuous stirred tank reactor (CSTR) experiments at 55 °C. Rendering wastes have high protein and lipid contents and are considered good substrates for methane production. However, accumulation of digestion intermediate products viz., volatile fatty acids (VFAs), long chain fatty acids (LCFAs) and ammonia nitrogen (NH₄-N and/or free NH₃) can cause process imbalance during the digestion. Mono-digestion of rendering wastes at an organic loading rate (OLR) of 1.5 kg volatile solids (VS)/m³ d and hydraulic retention time (HRT) of 50 d was unstable and resulted in methane yields of 450 dm³/kg VS_fed. On the other hand, co-digestion of rendering wastes with potato pulp (60% wet weight, WW) at the same OLR and HRT improved the process stability and increased methane yields (500–680 dm³/kg VS_fed). Thus, it can be concluded that co-digestion of rendering wastes with potato pulp could improve the process stability and methane yields from these difficult to treat industrial waste materials.     

常温CSTR部分亚硝化影响因素及工况优化研究

为了更好地实现并维持稳定的部分亚硝化效果,以低氨氮人工配水为研究对象,采用连续流完全混合式活性污泥法(CSTR),在常温条件下对部分亚硝化工艺的影响因子和准佳工况进行了研究。结果表明,HRT=(3.0±0.2)h,DO为0.40～0.50 mg/L,回流比R=20%～30%时,平均氨氧化率为53%,且工艺出水NO2--N/NH4+-N平均为1.11∶1,适宜作为系统长期稳定运行的工况。若持续缩短HRT会导致反应器内污泥浓度降低,部分亚硝化效果受到影响。反应器在上述工况运行时,DO=0.50 mg/L是亚硝化率下降的临界浓度;系统进出水pH差值可良好表征出水亚硝酸盐氮与氨氮浓度的比例。     

Coupling effects of venting and inerting on explosions in interconnected vessels

The coupling effects of venting and CO₂ inerting on stoichiometric methane-air mixture explosions were investigated in an isolated vessel and interconnected vessels. The results indicate that venting mitigates the explosion intensity, especially for small vessels. For vessels connected by pipes, a venting design following EN 14994 (2007) and NFPA 68 (2013) could not meet the venting requirements. For an isolated big vessel and interconnected vessels, increasing the CO₂ volume fraction (Φ) from 0 to 15.0 vol% decreased the maximum explosion overpressure (P_max) and maximum rate of overpressure rise ((dP/dt)_max) and delayed t_max. For closed interconnected vessels, P_max varied approximately linearly with Φ. For both isolated vessel and interconnected vessels, the coupling effects of venting and CO₂ inerting on methane-air explosion were more efficient than those of individual mitigative method (that is, venting alone or CO₂ inerting alone).