LNG 汽车产业发展可行性的模糊分析

LNG 汽车产业是一种新兴的汽车产业,做好LNG 汽车产业发展的可行性研究和评价是推广这项新兴产业的前提和基础。从技术、经济、环保、资源保障能力4 个方面分析了发展LNG 汽车产业的可行性,构建了LNG 汽车产业发展可行性评价指标体系,通过建立合理的因素集、评价集、权重集等,提出了利用多层模糊综合评价对发展LNG 汽车产业可行性进行评价的具体方法,并运用实例进行具体的计算和分析。多层模糊综合评价结果表明,LNG 汽车产业发展的可行性是非常好的,推广和使用LNG 汽车是十分可行的。可行性评价结果可以为政府或企业发展LNG 汽车产业的科学决策提供重要依据。     

中东与世界液化天然气贸易

阐述了中东液化天然气的生产和贸易现状，分析了影响中东天然气贸易的因素，并对中东液化天然气的出口和贸易进行了展望。     

A Methodology for Risk Analysis Based on Hybrid Bayesian Networks: Application to the Regasification System of Liquefied Natural Gas Onboard a Floating Storage and Regasification Unit

This article presents an iterative six‐step risk analysis methodology based on hybrid Bayesian networks (BNs). In typical risk analysis, systems are usually modeled as discrete and Boolean variables with constant failure rates via fault trees. Nevertheless, in many cases, it is not possible to perform an efficient analysis using only discrete and Boolean variables. The approach put forward by the proposed methodology makes use of BNs and incorporates recent developments that facilitate the use of continuous variables whose values may have any probability distributions. Thus, this approach makes the methodology particularly useful in cases where the available data for quantification of hazardous events probabilities are scarce or nonexistent, there is dependence among events, or when nonbinary events are involved. The methodology is applied to the risk analysis of a regasification system of liquefied natural gas (LNG) on board an FSRU (floating, storage, and regasification unit). LNG is becoming an important energy source option and the world's capacity to produce LNG is surging. Large reserves of natural gas exist worldwide, particularly in areas where the resources exceed the demand. Thus, this natural gas is liquefied for shipping and the storage and regasification process usually occurs at onshore plants. However, a new option for LNG storage and regasification has been proposed: the FSRU. As very few FSRUs have been put into operation, relevant failure data on FSRU systems are scarce. The results show the usefulness of the proposed methodology for cases where the risk analysis must be performed under considerable uncertainty.     

Assessment for Catastrophic Risks

Records of nonoccurrence of catastrophic accidents from technologically based industrial operations, such as nuclear power generation and liquefied natural gas (LNG) transportation are sometimes cited as evidence of the safety of such operations. The appropriateness and inappropriateness of different types of models of accident processes for these systems are discussed. Selectivity biases in defining both die numerator and denominator for accident rates are shown to be important to the size of the estimated rate and these are illustrated by examples. Inferential approaches to estimating a rate based on zero occurrences are briefly discussed. The conclusion reached is that a record of zero occurrences is of cold comfort in ruling out catastrophic events. Experience, unless it is interpreted by strong models and assumptions, helps little to establish very small probabilities of a catastrophe.     

LNG绕管式换热器管内压降和热传递的数值模拟

针对目前LNG绕管式换热器在设计时存在管内低温传热的不确定性,采用FLUENT软件分析了大螺距螺旋管 在湍流状态下管内的压降和冷却传热特征。研究中分别采用4.8 MPa的气态甲烷和液态甲烷为介质,探讨了螺旋管结 构、雷诺数Re、普朗特数Pr对压降和努塞尔数Nu的影响。结果表明：管径、缠绕直径、Re及Pr对压降和/VM的影响较 大;螺距对传热和压降影响较小,可忽略不计。并将模拟值与Jayakumar等半经验值做对比,结果趋势一致。最后拟合出 适用于LNG低温冷却状态下的Nu公式,为LNG绕管式换热器的工艺计算提供一定的依据。