摘要天然气（Natural Gas，NG）作为一种清洁能源，具有燃烧热值高、资源量丰 富、碳排放量低的优点，是目前世界上各个国家大力推广使用的环保型燃料。由 于气态天然气体积较大，不易运输，故通常将气态天然气经过净化处理后，液化 成液态天然气（Liquid Natural Gas，LNG），其体积只有气态天然气的 1/600，在使 用时，将其汽化成气态天然气即可。随着我们国家大量进口天然气，在船舶行业， 出现了一种新型动力船——LNG 动力船，且在未来几年内，我国将大力推广 LNG 动力船的建设和使用。84879

LNG 是-162℃的液体。根据热力学第一定律可知，液态天然气在汽化时会释 放出大量的冷能。在当前严峻的能源形势下，各国都在纷纷进行对 LNG 汽化冷能 的回收和利用工作。本文将以正逐渐兴起的 LNG 动力船为研究对象，通过分析 LNG 动力船动力系统的运行特性，提出一种采用梯级 LNG 汽化工艺及冷能利用耦 合利用的技术方案，进行了利用 LNG 冷能的多温冷库设计与分析，包括对多温冷 库基本设计参数的确定、制冷流程的设计、冷库制冷剂的比较与选取，同时针对 所设计的 LNG 动力船多温冷库，进行具体的热经济效益分析和环境效益分析，对 LNG 动力船多温冷库制冷方案所能创造的经济效益和节能效益进行论证 。本文提 出的技术方案实现了 LNG 汽化释放的高品质冷能的梯级利用，提高了冷能的利用 率，从而更加充分、合理的利用 LNG 汽化所释放的高品质冷能，减少了由于 LNG 冷能的浪费对海洋环境造成的污染。

毕业论文关键词：LNG 动力船；汽化冷量；多温冷库

Abstract Natural Gas (NG), as a clean energy with many advantages of high heat of combustion, rich resources and low carbon emissions, is currently used and promoted in the world。 Due to the larger volume of nature gas in the gaseous state, the transportation for nature gas usually in the liquid state, so the nature gas was liquified into the liquid state for transportation。 During this procese, the liquid natural gas (LNG) whose volume is only 1/600 compared to the natural gas。 However, when the LNG was used as the power source, it should be vaporized into the gaseous state。 With the large importation

of the natural gas in our country, in the shipbuilding industry, a new powered   ship——

LNG powered ship is designed and manufactured。 In the next few years, the LNG powered ship will be vigorously promoted and widely produced in our country。

LNG is a liquid state with temperature is -162  ℃。 According to the first law of

thermodynamics, the liquid natural gas will release large amounts of cold energy  when it vaporizing into gas。 Under the stringent energy situation, the cold energy of LNG has been utilized, when it vaporized, by many countries。 By analyzing the power system of LNG powered ship, the multi-temperature cold storage, which utilized the cold energy result in LNG vaporizing process of LNG powered ship, was designed and investigated in this paper。 The basic parameters and the cooling process were calculated and the refrigerant was selected based on the cascaded utilization theory of cold energy。 At the same time, the heat economic benefit and the environmental benefit were analysed。 The system designed in this paper improve the utilization of the LNG cold energy, and make fully  utilization  of  the  high  quality  of  LNG  cold  energy,  and  reduce  the   ocean’s

pollution resulted in LNG cold energy when it vaporized。

Keywords: LNG powered ship; Vaporization cold; Multi-temperature Cold Storage

目 录

第一章