摘要天然气（Nature Gas，NG）作为一种燃烧热值高，对环境污染性小的清洁能源， 广泛的应用在各个领域。近年来船舶废气污染越来越为严重，国际海事组织今年出台 了最严的 IMO Tier III 排放标准，在此背景下以 LNG（Liquid Nature Gas，LNG）作 为发动机燃料已经成为了公认的解决办法，于是 LNG 动力船进入了高速发展的纪元。 但是 LNG 进入船舶主机时，必须由-163ºC 升温到 30ºC 使用，因此 LNG 汽化是 LNG 动力船的核心过程，有必要对其进行探讨和研究。84897

本文通过分析目前汽化器的换热介质结冰及结构尺寸庞大等问题，选择合适的热 源、中间换热介质、传热体结构以及材料等，提出梯级汽化器的汽化方案，得到汽化 器结构的初步设计。然后根据 LNG 汽化热力过程，采用热节点网络法对汽化器结构 进行热力学分析，其中主要分析了贯穿 LNG 腔体与丙烷腔体、贯穿丙烷腔体与热源 腔体以及贯穿 NG 过热区的换热过程。之后依据热平衡理论，获得了需要提供给 LNG 汽化的热负荷、NG 过热热负荷等参数，从而确定各相关状态点的参数，然后对汽化 器结构的相关尺寸进行分析及计算，确定汽化器的结构尺寸。同时依据某典型 LNG 动力船的船型及主机功率特征，进行 LNG 梯级汽化器的汽化工艺设计及汽化性能分 析，获得满足功率输出为 24000kW 的 LNG 动力船的汽化需求。最后通过经验公式算 出汽化器中各部分的压力降，得到汽化器的性能指标，从而完成对梯级汽化器的所有 参数设计。

毕业论文关键字：LNG；梯级汽化器；LNG 动力船；热管

Abstract Nature Gas, a kind of clean energy with high calorific value, is widely used in various fields。 In recent years, ship exhaust pollution is becoming more and more serious, the International Maritime Organization introduced the most stringent IMO Tier III emission standard this year, under this background, using LNG as the engine fuel has become the accepted solution, then LNG powered ship entered the high-speed development era。 But when LNG flows into the ship’s host, it must be heated to 30 degrees from -163 degrees。 Therefore, LNG vaporizing is the core process of the LNG powered ship, and it is necessary to be explored and researched。

In this paper, through the analysis of the vaporizer’s problems of the heat transfer medium icing and large size structure, then choose the appropriate heat source, intermediate heat transfer medium, heat transfer structure and the choice of materials, in view of these problems, to complete the design of the technical path of vaporizer and the vaporizer structure preliminary design。 Afterward, according to the thermodynamic process of the LNG vaporization, mainly analyses the vaporizer structure by thermal network method, which includes the thermal resistance of the heat pipe through the LNG cavity body and propane cavity, the propane and the cavity of the heat source, and throughout the NG overheat region of heat pipe thermal resistance analysis。 After heat balance calculation of three process of the vaporizer, get the heat load of LNG vaporizing, NG overheating parameters such as heat load, so as to determine the parameters of each state point, and then designed and calculated the relative size of vaporizer structure。 At the same time, according to a typical LNG powered ship hull and engine power characteristic, to finish LNG cascade vaporization process design and analysis of vaporization performance, so as to meet the power output for the demand of vaporization 24000kw NG powered boat。 At last calculated the pressure drop of all parts of the vaporizer and get the performance of the vaporizer through empirical formulations, so as to complete the design of all parameters of the cascade vaporizer。

Keywords: LNG; Cascade Vaporizer; LNG Powered Ship; Heat Pipe