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由于地理、用户使用条件和峰段要求的限制，LNG槽车在输送天然气方面有着巨大的市场需求，是管道输配的重要补充手段。LNG槽车往往需要在没有机械动力的情况下，依靠配套的增压汽化器提供压力源，采用顶部气相空间加压方式卸载液体。槽车常配用的汽化器有空温式汽化器和水浴式汽化器两种形式，空温式汽化器使用空气作为热源，节约能源，操作费用低廉。对于长江三角洲地区，常年气候温和湿润，最低气温在零度以下的天数屈指可数，使用空湿式气化器完全满足生产要求。文章介绍LNG槽车自增压空温式汽化器的设计计算，其中包括天然气气相和液相物性的计算方法，以及空温式汽化器的热力计算。然后给出空温式汽化器的换热面积和结构尺寸等设计参数。

Design Calculation of Self-pressurized Air-heated Evaporator for LNG Transportation Tank

Because of the limitation of the geogra phical and customer used conditions and peak zone demand,the liquefied natural gas (LNG) transportation tank is of great market potentialities in transporting natural gas,being an important supplementary means for pipeline transmission an d distribution.The pressure source is always needed to be provided by a matched pressurized evaporator for the LNG transportation tank under the condition of ha ving no external mechanical power,i.e.to apply self pressurized mode in the top gaseous space to offloading liquid.There are two kinds of evaporator matched fo r the LNG transportation tank,i.e.air heated evaporator and aquathermal evapora tor,the former may economize on both energy source and investment,taking air as i ts heat source.The air heated evaporator can fully meet the demand for offloadi ng liquid at the Yangtze River delta region where the climate throughout the yea r is gentle and humid and only very few days' lowest atmospheric temperature was below zero centigrade.The design calculation of the self pressurized air heat ed evaporator for LNG transportation tank,including the gas phase and liquid pha se physical property calculation of natural gas and the thermal calculation of t he air heated evaporator,are introduced,then the design parameters,as the heat exchange area and physical dimensions,etc.,of the air heated evaporator are giv en out in the paper.