Utilization of LNG cold

This paper will discuss the utilization of LNG cold in Japan. Discussion is concentrated on the following: temperature conditions of both direct and indirect utilization; restriction in quantity and mode of cryogenic energy utilization; distance from LNG terminals to cold utilization plants; cooling system for LNG cold utilization plants, and emergence of cryogenic energy utilization complexes.     

LNG冷能用于气体直接接触法制取冰浆研究

阐述了LNG冷能利用的背景,分析了LNG冷能梯级利用原理,提出了用LNG代替传统制冷系统作为冷源的气体直接接触式冰浆制取改进方法。LNG冷能不同利用方式的对比计算结果表明,通过利用LNG冷量可将系统的能效系数提高到原来的3倍左右。LNG直接利用时冷量损失大于LNG梯级利用。随着LNG初始利用温度的升高,LNG冷量损失近似线性下降,而所需的LNG质量流量则呈现"J"字型增长趋势。     

LNG冷能回收及梯级利用研究进展

本文在分析LNG冷能利用特点的基础上,根据"高能高用、低能低用、温度对口、梯级利用"原理,总结了LNG冷能用于发电、空气分离、海水淡化、CO2捕获和低温冷库等单元利用的工艺方法、温位区间、工质选择以及优缺点,对比了现有的LNG冷能梯级利用工艺温度范围,以实现温位的良好匹配.并分别针对大型LNG气化站、小型LNG气化站和...     

液化天然气(LNG)的冷量利用

阐述了液化天然气冷量(火用)数学模型和冷量(火用)特性分析,介绍了液化天然气冷量利用的几个方面,包括发电、空气分离、制取干冰和冷库.我国液化天然气的冷量利用潜力巨大.在兴建LNG接收站时,应当重视采用该项技术,有效回收LNG的冷量,节省能源.     

LNG冷能综合利用研究

简介了LNG冷能利用的背景和现状,从LNG冷能综合利用的意义出发,对LNG冷能的可用性以及用冷特性进行分析,最后指出了LNG冷能综合利用方法策略和集成模型,利用的实施条件和解决措施。     

LNG冷能在液体空分设备上的应用研究

介绍液化天然气(LNG)冷能利用的必要性和LNG冷能空分设备的流程,分析LNG冷能空分设备所具有的节能、节水和投资成本较高的特点,阐述LNG冷能空分设备的设计要点。     

液化天然气冷能利用发电技术浅析

阐述了国内外LNG利用的形势,论述了LNG作为燃料的优势.通过分析LNG冷量利用原理及对LNG进行的分析,得出回收LNG冷量发电不仅有效利用能源,而且减少机械制冷造成的大量电能消耗,具有可观的经济效益和社会效益.对国内外利用LNG冷量发电方式进行总结分类,具体给出一些典型流程图和成功的应用范例.     

LNG冷能空分技术的开发与应用

随着我国LNG接收站的建设,高效利用LNG冷能具有十分重要的意义。介绍了采用自主专利技术的LNG冷能空分装置的原理、流程特点、关键技术,并介绍了LNG冷能空分装置的工业化应用实例。分析了LNG冷能空分的工业化应用中存在的一些问题,提出了相应的建议。     

BOG冷能在LNG船上的综合利用研究

针对LNG船舶每日产生的低温蒸发气的冷能浪费问题,提出了通过利用氮气闭式循环气体透平技术和冷能的梯级利用,回收这部分原本被浪费的冷能来发电,这部分冷能还能用来供给冷库用以制冷,同时升高蒸发气的温度供给燃烧,可以起到提高经济性及合理利用能源的目的.该文将为冷能综合利用技术在LNG船上实际应用建立理论和技术基础.     

LNG and world energy needs. Part 1: Gas liquefaction and world resourcesLa liquéfaction des gaz et ressources mondiales. 1e partie: les GNL et les besoins mondiaux en énergie

The development of international trans-shipment of LNG will be reviewed, comparing the present achievement with the world potential. The scope for further development will be discussed together with the problems that delay it.Base-load liquefaction plants have already achieved a high level of efficiency and reliability, and the possibility of major improvement has become small. Present technical interest centres on the practicability of offshore liquefaction, including the problems of liquefaction on a floating barge, floating storage and flexible pipeline systems for LNG transfers.Land-based LNG storage systems have developed greatly, especially in Japan, where important strides have also been made in utilising the ‘cold’ available from re-evaporation. Whilst significant developments have been made with both above-ground and in-ground storage the present preferences appear to lie with a compromise solution involving an insulated tank partially submerged in the ground, the excavated earth being mounded around the tank up to the level of the tank top.There are now fleets of ocean-going tankers for LNG, and a few are laid-up awaiting charter. The largest has a capacity in excess of 130 000 m³. Several different insulation systems are employed, the criteria being cost, evaporation losses and safety. Much attention is being devoted to the elimination of hazards which could arise with shipping accidents.Other uses of LNG are relevant to energy conservation on a smaller scale. These include peak-shaving plants, the enrichment of lean natural gas, satellite stations and diurnal storage.     

面向LNG汽车的发动机排气与低温燃料温差发电器研究

为实现液化天然气（LNG）汽车的节能,提出了利用温差发电器（TEG）回收发动机排气（EG）的废热和低温燃料的冷能。指出了基于冷源所在的低温区,以及EG与LNG之间的大温差这两个特点,TEG的热电转换效率会高于常规。基于对小型LNG汽车中典型燃料系统的分析,设计了进行能量回收的两种系统流程,计算了其中各状态点的参数、及各换热器中布置温差发电器后的热电转换效率,得到了系统总的回收功率。结果表明,汽化器系统的回收功率大于自复温系统;在两种系统中,合理选取多种材料相较于仅用单种材料,TEG的回收功率更大。     

空分装置利用LNG冷量的热力学分析

简介了LNG冷量用于空分装置的实际例子及其节能效果 ;从空分装置液化率改变和压力改变两方面对利用LNG冷量的空分装置进行了热力学分析 ;最后指出 ,空分装置利用LNG冷量可达到多产液体、节省投资和运行费用的效果。     

基于LNG冷能的低温动力循环研究进展

液化天然气(LNG)是一种应用日趋广泛的清洁能源,构建LNG冷能低温动力循环成为回收冷能的重要途径。本文首先讨论了LNG侧参数、循环工质、设备进出口参数等重要参数对基本LNG冷能动力循环的影响;其次分析和总结了诸多LNG冷能动力循环的结构改进类型,包括朗肯循环、布雷顿循环、卡琳娜循环和复合循环。文章最后指出了参数研究的实际工程意义和循环结构改进的多样性,并指出下一步研究应围绕有机混合工质组分配比、模拟与实验相结合等方面展开。     

基于液化天然气低温冷藏车的相变蓄冷实验

针对以水为相变工质通过铜质圆管壁与低温氮气换热发生固液相变问题,通过测温和可视化测量手段模拟研究固液相变贮存LNG冷量过程,获得管内低温气体、管外液相区温度分布及冰层图相,分析了管内换热和液相区自然对流综合影响下的冰层变化和分布特性,结果表明:该换热问题具有典型的变壁温变热流密度的热边界条件;冰层厚度在有限时间内近似线性增长,且沿管长锥状分布、冰层锥度随时问呈对数增长趋势;由于液相区水的密度反转效应使自然对流主流向发生改变,导致上下壁面冰层厚度发生反转.     

Fatigue crack propagation behavior in AISI 304 steel welded joints for cold‐stretched liquefied natural gas (LNG) storage tank at cryogenic temperatures

AISI304 steel welded joints are used in cold‐stretched liquefied natural gas (LNG) storage tanks used for storing and transporting of liquefied gases. Compared with a conventional liquefied natural gas storage tank, a cold‐stretched liquefied natural gas storage tank has many advantages such as reduced thickness, light weight, low cost and low energy consumption. However, liquefied natural gas storage tanks can be subjected to alternative loads at cryogenic temperatures; thus, it is important to investigate the fatigue crack propagation behavior in AISI 304 steel welded joints at cryogenic temperatures. Specimens were machined from a cold‐stretched liquefied natural gas storage tank with a welding structure. The crack length was determined using compliance method and confirmed by examination with traveling microscope. Fatigue crack propagation rates were evaluated at various stress ratios and temperatures. The fatigue crack growth rate of all specimens a little appears the effect of stress ratio, but it has a great influence at a cryogenic temperature. The fatigue crack growth rate of longitudinal welded joint is the fastest at room and cryogenic temperature. Fracture mechanism in the specimen is examined using a scanning electron microscope.     

基于液化天然气(LNG)冷量的废旧橡胶低温粉碎工艺流程

探讨了废旧橡胶低温粉碎中LNG冷量的利用问题.用空气作为中间冷媒,将LNG冷量先传给空气,再由空气去喷吹冷却胶粉.设计了此冷却换热的工艺流程,进行了物料及冷量的衡算,以实现冷量的有效利用.     

回收PAFC废热与LNG冷能的动力循环分析

在液化天然气(LNG)作为磷酸型燃料电池(PAFC)燃料的电站中,大量的LNG冷能和PAFC废热被释放.提出一种利用LNG和环境作为冷源的双冷源动力循环和LNG直接膨胀做功相结合的回收PAFC废热和LNG冷能的能量系统.对循环的分析表明,当工质为水时,该循环对PAFC废热和LNG冷能的可用能的回收效率最大可达47%左右.     

LNG蓄冷及其冷能的应用

分析了中国液化天然气的发展,讨论了液化天然气的性质及冷能的运用前景,构造了液化天然气蓄冷装置并对其应用作了说明,着重论述了LNG蓄冷装置在LNG船上的应用情况.     

LNG汽车冷能回收在低温冷藏车中的应用

LNG(液化天然气)作为绿色汽车燃料,可以减少汽车尾气排放造成的空气污染。此外,LNG在汽化、温升的过程中释放大量的冷能。本文提出利用乙二醇溶液做冷媒的蓄冷系统对该冷能进行回收。并将回收的冷能用于低温冷藏链中的冷藏运输过程。系统参数计算结果表明:回收的冷能满足中短途小型冷藏车的冷负荷需求。     

Effect of cryogenic temperature on the flexural and cracking behaviors of ultra-high-performance fiber-reinforced concrete

This study investigates the flexural and cracking behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC) before and after exposure to cryogenic temperatures for liquefied natural gas (LNG) storage tank applications. Normal concrete (NC), which has been used to make LNG storage tanks in Korea, was also considered for comparison. In order to evaluate the cracking resistance of NC and UHPFRC, several edge-type slabs were fabricated and tested by restraining their thermal deformation. Four-point bending tests were also performed to estimate the flexural performance before and after cryogenic cooling. Test results indicate that UHPFRC exhibited higher resistance to microcrack formation under these conditions. UHPFRC also showed substantially better flexural performance, both before and after exposure to cryogenic cooling, compared to NC. In addition, the microcracks in UHPFRC that were induced by the pre-cracking load were suddenly and effectively filled with calcium carbonate (CaCO₃), which was formed by a chemical reaction between melting water and calcium ions. This was verified by energy dispersive X-ray spectroscopy analysis. CaCO₃ formation resulted in enhanced flexural performance, including higher strength, deflection capacity, and energy absorption capacity, as compared to the virgin UHPFRC specimens without any cracks.