Simplified multiple equations' inverse problem of vented vessels subjected to internal gas explosions

This paper analyses the experimental data reported by Höchst and Leuckel (1998) for combustion in partially confined vessels and uses the data from these experiments to establish the burning rate based on a simplified model for the combustion process in such vessels. The model establishes three fundamental parameters which are necessary in characterizing the combustion process. These are: i) the burning rate, ii) the fraction of vent area occupied by burnt gas (or discharge sub-model), and iii) the vent area model (if cover mechanisms with variable vent areas are utilized). A set of independent equations is derived to determine the burning rate according to conservation of mass and volume for each gas fraction separately along with a general equation based on general volume conservation. Using this method we are able to describe the combustion process and examine the effect of various discharge models. The advantages of the model presented here include rapid applicability and a valuable analysis to derive mass burn rate and other useful parameters using experimental data from vented explosions with reasonable residual reactant values. Based on these results, the correct interpretation of the obtained burning rate can be used in order to explain the correct prediction of flame velocity and position according to a reasonable discharge model. The paper also evaluates the suitability of several discharge models for phenomenological models of vented explosions. The most appropriate is a Heaviside step function which considers that only unburnt gas is initially expelled, with that component decreasing and the burnt gas component increasing until finally only burnt gas is expelled. The obtained results in this study can be used to predict the burning rate behavior and the combustion process of similar problems.     

Numerical study of choked two-phase flow of hydrocarbons fluids through orifices

Valves and orifices are the most widely devices of flow control used in oil and gas industry. In particular, they are installed in relief piping system in order to control the discharge flow during potential plant overpressuring scenarios, thus ensuring plant safety. It is a common practice to flow liquid and gas mixtures through such restriction devices.Rigorous models are available to precisely size pressure relief devices operating in single phase flow; however for two-phase flow, no models are considered sufficiently reliable for predicting the relevant flow conditions.In the present paper, two-phase flow of hydrocarbons fluids through an orifice under critical conditions has been numerically investigated.The existing literature has been analyzed and data on two-phase flow of highly volatile mixtures of hydrocarbons through openings have been collected. A comparison has been carried out with numerical simulations carried out by the multiphase flow simulation tool OLGA by SPT.The Henry–Fauske model has been used as orifice choke model and the orifice discharge flow coefficient, required as input by OLGA, has been calculated by Chisholm's model.Comparison between OLGA's results and experimental data shows that Henry–Fauske model markedly underestimates the mass flow rate through the orifice, if Chisholm's model is used to calculate discharge coefficient. It was found that the error of the model could be minimized using different values of orifice discharge coefficient (C_d).A new discharge flow coefficient model, suitable for choked two-phase flow across orifices, is proposed in this study and it has been determined to match the above mentioned experimental measurements.     

四川省制浆造纸行业可持续发展建议

造纸业是与民生关联度极高的行业.为改变国内造纸行业污染局面、整合企业规模、合理原料结构、提高技术装备、改革落后生产工艺,国家先后出台了多项政策规定.特别是2008年新的<制浆造纸工业水污染物排放标准>(GB3544)颁布后,四川省制浆造纸行业面临巨大的整改压力.如何抓住产业调整机遇,加快产品结构调整和生产方式转变,努力...     

青岛石化厂污水回用情况探讨及对策

针对青岛石化厂污水处理场改扩建工程污水深度处理设施及回用情况进行了说明，并提出建议。     

宽间距长芒刺静电除尘技术的应用

宽间距长芒刺静电除尘技术是国家“九五”科技攻关课题所取得的成果之一。由于采用宽间距、长芒刺放电极结构和极板涂敷特种防腐涂层 ,降低金属材料消耗的同时 ,降低了宽间距电除尘器电压工作范围 ,避免了使用超高压电源所致的绝缘难题 ,大大减少了静电除尘器的初期投资。笔者将该成果应用于某水泥厂生料磨系统 ,现场使用效果表明 ,该除尘技术不仅可有效改善作业环境 ,且工作电流、电压稳定 ,收尘效率高 ,设备阻力低 ,运转稳定可靠。     

物料衡算法计算燃煤SO_2排放总量的探讨

分析了现行燃煤ＳＯ_２排放总量计算方法的优缺点，提出了一种适合基层环保部门准确计征燃煤ＳＯ_２排污费使用的新方法。     

江苏省化学工业主要水污染物排放地方标准研究

江苏省化学工业主要水污染标准的制订对于促进我省化工企业的清洁生产．保护生态环境有着重要的现实意义。介绍了江苏省化学工业水污染物排放的情况,对化工生产技术水平和水污染控制情况进行了分析,在此基础上确定了主要水污染污的排放限值。并进行了达标和环境效益分析。     

万元产值废水排放量的GTPM（1）模型步长指数变换建模方法研究

在万元产值废水排放量这类环境系统中，既有单调递增或单调递减的单调系统，也有前期单调递增后期单调递减的非单调系统。本文研究提出的ＧＴＰＭ（１）步长指数变换建模方法，对于前增后减的非单调系统是非常有效的。应用实例表明，此方法不仅为一控制开辟新途径，也进一步拓宽了灰色预测方法在环境系统中的应用范围。     

环境税税制设计的探讨

结合国外经验与中国国情，论述了环境税的设计原则，。探讨了在我国环境税时，税制三大要素：税种，税基和税率的制定及实施方法。     

电收尘器的目标管理与实践

电收尘器投用初期收尘效果较好，使用一段时间后常因管理原因致出口粉尘排放总量增加，生产实践中将电收尘器相对回围窑的运转率作为电收尘器目标管理的考核指标，落实配套措施，调动岗位人员的工作积极性，最大限度地减少出口粉量的排放。