低温管道保冷层厚度影响因素分析

采用最大允许冷损失量公式计算低温管道保冷层厚度,通过分析环境温度与相对湿度对保冷层厚度的影响,结合实际建设经验,提出低温管道保冷层厚度选择的较优原则。     

LNG气化站工艺设计及施工管理

通过对LNG气化站工艺设计中的气化站选址、设备选择、卸车、管道预冷、储罐气化、气化气处理等进行了分析,对生产区和辅助区施工管理、LNG的储存、LNG的潜在危害进行了总结.结果表明:LNG气化站工艺设计及施工管理过程较复杂,需要注意的细节较多,只有建立起完善的工艺设计和施工管理,才能确保LNG气化站的建设质量.     

LNG应急储备中心气化设备的配置及优化应用

[目的]LNG（液化天然气,Liquefied Natural Gas）储备中心气化区工艺设备运用的技术分析与调研,是为解决西安引镇LNG应急中心气化区单一空温气化器编组运行结霜结冰问题而展开。[方法]内地在用的LNG气化技术主要有空温式与水浴式气化两种形式,空温式气化器在大负荷与低温季节运行时,设备周边易起浓雾,外表常会结霜结冰,水浴式气化器则无此现象。通过调研比较近年各地LNG储备中心以及沿海LNG接收站等各类场站气化工艺区气化设备的运行情况,工程上采用独立的LNG水浴式气化器能够实现设备外表无霜冰雾的气化生产;利用水浴式气化器与空温式气化器组合系统联合优化LNG的气化运行,既可获取利用空气蕴含的热能进行LNG气化生产,也能消除低温起雾及冰霜对LNG气化生产的影响。[结果]内地大储存量液化天然气的气化工艺,能够不受低温影响,顺畅完成气化过程的生产。[结论]构建绿色能源体系,基于新型能源网络的形成,高效能源输配与储存转换技术以及天然气与风光水氢等气电再生清洁能源的融合互补发展,完善的储能工程与技术具有重要支撑作用,大型LNG气化技术的优化是一项重要的工程实践。     

LNG工业链

LNG产业链是一条贯穿天然气产业全过程的资金庞大、技术密集的完整联系。由陆地和海上油田开采的天然气在液化工厂经过预处理后进行液化，生产的LNG按照贸易合同，通过船运到LNG接收站储运、再气化，经管网送到用户。     

LNG气化站安全管理系统技术应用探讨

在管输天然气供应不足的情况下,LNG已成为无法使用管输天然气供气城市的主要气源或过渡气源,也是许多使用管输天然气供气城市的补充气源或调峰气源。文章介绍了如何实现LNG气化站的安全运行和管理。     

低温储罐自增压过程仿真研究

随着低温技术的发展,低温液体在新能源领域的应用日趋广泛,各行各业对储存和输送低温液体的低温容器的需求也不断增长,尤其在工业、农业、国防、科研和医疗方面更为明显。LNG储罐作为液化天然气的主要储存装置之一,是液化天然气产业链中重要的一环。针对LNG储罐自增压过程的重要性。本文基于能量方程和质量方程建立了自增压过程的数学模型,编写了LNG储罐自增压过程的程序。计算结果得出自增压过程中各区的温度变化规律,然后对其进行分析。同时针对不同初始充装率、不同增压气体温度下的自增压过程进行研究,分别分析了它们对自增压过程的影响,该研究对液化天然气储罐的结构设计、材料选择、汽化器的设计有较强的指导意义。     

长输管道大型定向钻穿越的监督检验

我国从境内外进入的液化天然气（LNG）由海陆运输至港口，气化后由管道输送至使用对象，这已成为我国东南部沿海地区解决能源短缺问题的一条新的途径。长输管道作为长距离输送流体介质的一种运输载体在输送LNG方面有着无可替代的优势。本文就长输管道定向钻穿越监检中发现的若干问题以及处理措施进行专项的阐述和探讨。     

基于遗传算法优化双燃料发动机LNG气化流程的研究

液化天然气(LNG)气化器是LNG发动机的关键部件,其流程优化涉及多变量非线性问题。我们从热力学角度对ME-GI型发动机的LNG气化流程进行研究,用HYSYS建立仿真模型,通过MATLAB嵌入遗传算法优化气化工质的流量、温度和热水流量,从而降低总的泵功耗。研究结果表明,遗传算法对LNG气化器流程优化快速而精准,优化后的比功耗较优化前低14.5%。     

新奥燃气胶州湾大区调峰储气方案研究

分析了新奥燃气胶州湾大区调峰储气的现状,预测了2018年季节调峰储气量、日调峰储气量及应急储气量,对该大区天然气的调峰储气方案进行探讨,确定了建设调度中心LNG储配站集中储存,再通过槽车运输至各LNG气化站的方案。该方案的实施有效解决了新奥燃气胶州湾大区储气调峰的问题,保障了安全供气。     

GT13E2燃气轮机"油改气"工程

论述了GT13E2燃气轮机改烧天然气(LNG)的必要性和可行性。燃气轮机“油改气”的方案和实施项目。LNG气化站方案论证、主要设备、工艺流程。燃气轮机油改气后的性能比较,环保评价。     

LNG: An eco-friendly cryogenic fuel for sustainable development

As the demand of natural gas has sharply increased in the last two decades at the global level, the transportation of natural gas from different parts (gas producing to the consuming areas) of the world has become more significant. Liquefaction of natural gas provides a safer and economical alternative for transportation and also increases its storage capabilities. The liquefaction process requires the natural gas to be cooled using various methods of cryogenic processes and also be depressurized to atmospheric conditions for easier and safer storage. LNG transported in cryogenic vessels offers several advantages over pipeline transport of natural gas especially when the gas consuming areas are far away from the gas producing areas. Moreover, LNG as an automobile fuel has a definite edge over other fuels.     

Utilization of the cryogenic exergy of LNG by a mirror gas-turbine

In the course of worldwide efforts to suppress global warming, the saving of energy becomes more important. Recently, LNG (liquefied natural gas) terminals in our country have received more than 50 million tons of LNG per year. Therefore, the utilization of the cryogenic exergy in connection with the regasification of LNG gains more and more importance. The aim of this paper is the recovery of the energy consumed in liquefaction using the MGT (mirror gas-turbine), which is a new kind of combined cycle of a conventional gas-turbine worked as a topping cycle and TG (inverted Brayton cycle) as a bottoming cycle. The optimum characteristics have been calculated and it is shown that this cycle is superior to the current-use gasification systems in employing seawater heat in terms of thermal efficiency and specific output. In the present cycle, the cold LNG is used to cool the exhaust gas from a turbine of a TG, and then the exergy of the liquefied natural gas is transformed, with a very high efficiency, to electric energy. The main feature of this new concept is the removal of an evaporation system using seawater.     

Potential applications using LNG cold energy in Sicily

According to previsions, natural gas could be the main energy source worldwide, inducing relevant geopolitical changes. Most likely, such problems will be solved with the development of a gas transportation mode alternative to traditional pipelines: liquefied natural gas (LNG). The global LNG trade has increased rapidly during recent years. A significant amount of energy is consumed to produce low‐temperature LNG, which has plenty of cryogenic exergy/energy. Therefore, the effective utilization of the cryogenic energy associated with LNG vaporization is very important. Sicily, with more than five million inhabitants, is the second biggest region of Italy and in this region will be realized two of the 11 gasification plants planned in Italy according to the regional energy master‐plan. This paper shows some interesting applications for the cold produced in gasification plants, e.g. for seawater desalination and for fresh and frozen food production and conservation. These applications seem very interesting for Sicilian situation and also can contribute to energy saving and greenhouse gases reduction to match Kyoto Protocol targets. Copyright © 2008 John Wiley & Sons, Ltd.     

Experimental study on liquid/solid phase change for cold energy storage of Liquefied Natural Gas (LNG) refrigerated vehicle

The present paper addresses an experimental investigation of the cold storage with liquid/solid phase change of water based on the cold energy recovery of Liquefied Natural Gas (LNG) refrigerated vehicles. Water as phase change material (PCM) was solidified outside the heat transfer tubes that were internally cooled by cryogenic nitrogen gas substituting cryogenic natural gas. The ice layer profiles were recorded in different cross-sections observed by digital cameras. The temperatures of cryogenic gas, tube wall and bulk region were measured by embedded thermocouples continuously. The results of the smooth tube experiments and the thermal resistance analysis prove that the main thermal resistance occurs in the gaseous heat transfer fluid (HTF) inner the tube. The enhancement of the inner heat transfer is achieved by adding wave-like internal fins. Besides, the results show that the ice layer not only increases in radial direction but also propagates in axial direction. It distributes in parabolic shape along the tube length due to the parabolic axial distribution of the tube wall temperatures. This investigation provides valuable references for the design and optimization of the cold energy storage unit of LNG refrigerated vehicles and for the numerical study on the unsteady two-dimensional conjugated heat transfer with phase change.     

A CO2 cryogenic capture system for flue gas of an LNG-fired power plant

In the present paper, a CO₂ cryogenic capture for flue gas of an LNG-fired power generation system is proposed, in which LNG cold energy can be fully utilized during the gasification process. First of all, the flue gas is compressed to facilitate the CO₂ solid formation and separation. Sequentially, the CO₂-removed flue gas expands to supply most of the cold energy needed for the cryogenic process. In comparison with traditional CO₂-capture systems in LNG-fired power generation cycle, the new system does not require gasifying excessive amount of LNG. Based on the HYSYS simulation, the CO₂ capture pressure and temperature are investigated as the key parameters to find the appropriate working conditions of the CO₂-capture system. The results show that the system can achieve a 90% CO₂ recovery rate or higher if the flue gas temperature can be lowered to less than ?140 °C.     

A liquefied energy chain for transport and utilization of natural gas for power production with CO2 capture and storage – Part 4: Sensitivity analysis of transport pressures and benchmarking with conventional technology for gas transport

A novel energy and cost effective transport chain for stranded natural gas utilized for power production with CO₂ capture and storage is developed. It includes an offshore section, a combined gas carrier and an integrated receiving terminal. In the offshore section, natural gas (NG) is liquefied to LNG by liquid carbon dioxide (LCO₂) and liquid inert nitrogen (LIN), which are used as cold carriers. In the onshore process, the cryogenic exergy in the LNG is utilized to cool and liquefy the cold carriers, LCO₂ and LIN. The transport pressures for LNG, LIN and LCO₂ will influence the thermodynamic efficiency as well as the ship utilization; hence sensitivity analyses are performed, showing that the ship utilization for the payload will vary between 58% and 80%, and the transport chain exergy efficiency between 48% and 52%. A thermodynamically optimized process requires 319 kWh/tonne LNG. The NG lost due to power generation needed to operate the LEC processes is roughly one third of the requirement in a conventional transport chain for stranded NG gas with CO₂ capture and sequestration (CCS).     

A liquefied energy chain for transport and utilization of natural gas for power production with CO2 capture and storage – Part 2: The offshore and the onshore processes

A novel energy and cost effective transport chain for stranded natural gas utilized for power production with CO₂ capture and storage is developed. It includes an offshore section, a combined gas carrier, and an integrated receiving terminal. In the offshore process, natural gas (NG) is liquefied to LNG by liquid carbon dioxide (LCO₂) and liquid inert nitrogen (LIN), which are used as cold carriers. The offshore process is self-supported with power, hot and cold utilities and can operate with little rotating equipment and without flammable refrigerants. In the onshore process, the cryogenic exergy in LNG is used to cool and liquefy the cold carriers, which reduces the power requirement to 319 kWh/tonne LNG. Pinch and exergy analyses are used to determine thermodynamically optimized offshore and onshore processes with exergy efficiencies of 87% and 71%, respectively. There are very low emissions from the processes. The estimated specific costs for the offshore and onshore process are 8.0 and 14.6 EUR per tonne LNG, respectively, excluding energy costs. With an electricity price of 100 EUR per MWh, the specific cost of energy in the onshore process is 31.9 EUR per tonne LNG.     

我国东南沿海液化天然气发展问题

近年来随着油价高启,液化天然气价格不断攀升,对中国液化天然气发展带来巨大的挑战,应客观冷静地规划国内液化天然气项目,按照市场承受能力有序实施进口液化天然气接收站建设,优先考虑广东、福建、浙江、上海和珠海经济发达省市。首先建成东南沿海天然气配送主干线,并在2015年左右形成中国东南沿海天然气供应网络,满足东南沿海省市经济发展对能源的需求,确保我国东南沿海地区能源安全稳定供应。     

Novel design of LNG (liquefied natural gas) reliquefaction process

This paper presents an investigation of novel LNG reliquefaction process where the cold exergy of subcooled LNG is utilized to recondense the vaporized light component of LNG after it is separated from the heavier component in a phase separator. The regeneration of cold exergy is especially effective as well as important in thermodynamic sense when a cryogenic process is involved. To verify the proposed idea, we performed an experimental study by facilitating liquid nitrogen apparatus to mock up the LNG reliquefaction process. Subcooled liquid nitrogen is produced for a commercial transportation container with a house-made atmospheric liquid nitrogen heat exchanger and then, having subooled degree of up to 19 K, it simulates the behavior of subcooled LNG in the lab-scale reliquefaction experiment. Recondensation of the vaporized gas is possible by using the cold exergy of subcooled liquid in a properly fabricated heat exchanger. Effect of heat exchanger performance factor and degree of subcooling on recondensation portion has been discussed in this paper. It is concluded that utilizing pressurized subcooled liquid that is obtained by liquid pump can surely reduce the pumping power of the vaporized natural gas and save the overall energy expenditure in LNG reliquefaction process.