基于天然气管网压力能回收的联合循环构思

随着天然气大量应用及其相关技术的不断发展,天然气管网的输送压力也越来越高,蕴含巨大的压力能。本文提出一种回收天然气管网压力能的燃气蒸汽联合循环系统：高压天然气通过在膨胀机内膨胀回收一部分能量,承担部分压气机消耗功,膨胀后的低温天然气用来依次冷却压气机进气和蒸汽轮机排气,然后回收部分排烟余热。本文定性分析了该系统流程相关部分给联合循环带来的收益,显示出提高联合循环效率和能源综合利用率的潜力。     

天然气的稳定可靠供应

天然气的稳定可靠供应是天然气市场发展的基础,也是天然气有效利用的保证。结合上海的天然气供应,从市场需求特点,多气源供应方式、合理配置管网、扩大储备、有效的调峰方式等方面分析了对确保天然气稳定可靠供应的作用。     

利用文丘里引射装置回收利用高压天然气压力能

介绍引射器的基本工作原理及其特性,并对该项技术中的关键设备超音速引射器进行设计研究。工程应用表明,采用文丘里引射装置是以高压天然气引射低压人工煤气,不仅拓宽了天然气的应用领域,而且通过回收天然气管网压力能,可大幅度节省电耗,降低生产运营成本,提高城市燃气管网运行的可靠性。     

上海天然气发展概况

天然气作为一种清洁高效的能源,是低碳经济的重要支柱。为了保证天然气的有效利用,稳定可靠的天然气供应是前提。文章以上海的天然气供应体系为例,分析了多气源供应、LNG储备、合理的管网配置、有效的调峰方式等对确保天然气稳定可靠供应的作用。     

上海天然气发展概况

天然气作为一种清洁高效的能源,是低碳经济的重要支柱。为了保证天然气的有效利用,稳定可靠的天然气供应是前提。文章以上海的天然气供应体系为例,分析了多气源供应、LNG储备、合理的管网配置、有效的调峰方式等对确保天然气稳定可靠供应的作用。     

DBS分区在北方某市供水管网压力管理中的应用

为了解决北方某市供水管网水厂出水压力不足、部分路段供水管网压力波动大、区域压力不均衡等问题,基于该市供水管网水力模型,综合考虑该市供水管网压力、水量、地形、行政管理区域等相关因素,对该市供水管网进行DBS分区。结果表明,该市管网实施分区管理后,A水厂供水负荷减小,用水高峰期出水压力不足问题得到解决;部分路段水压过高问题得到解决;各区块供水管网压力得到均衡。因此,DBS区块化管理在该市取得较明显效果,对改善供水管网管理水平具有一定的参考价值。     

代用天然气

将液化石油气在专用设备中加热挥发成气态．同时将若干空气（约占50％）混入，使其体积扩大，浓度稀释，热值降低（接近天然气的热值和华白指数），即可当作天然气供应。当天然气长输管网到达之后，代用天然气将由天然气替换，而先期投资建设的燃气管网、燃气表、及燃气灶具均不用更换，即可对终端用户顺利完成天然气接驳。     

提高天然气管道入室压力可行性研究

从实施分布式供能系统的需要出发，借鉴国外的技术标准和应用中积累实践经验，根据我国国内的技术发展趋势，对该课题在建筑、燃气供应系统工艺、管道及附件、原动机和安全监测保护等方面从设计、施工质量保证和科学的管理理念进行论述和研究，提高实施高级别压力天然气管道入室的可行性。     

天然气中下游管网的规划定位和终端的分类管理——广东与福建发展模式的比较

天然气价格改革进入关键阶段,而天然气中下游的发展模式也趋于多样化,在南方地区以广东省与福建省为典型。广东是"全省一张网",福建是"全省两张网",广东放开业务终端竞争,而福建继续保持特许经营制度,二者的根本差别在于省级管网规划定位和业务终端分类管理的不同。广东根据天然气管网自然垄断属性采取政府统一规划和监管,建设一张省级管网,提供天然气代输服务并独立核算。而福建省级管网由企业主导建设,建设两张省级管网,各自输送自有气源,不对外开放,重复建设。广东根据天然气终端(除居民等公用性质用户)的私人物品属性,实行经营许可制度,放开市场准入。福建依据供气方式对管道天然气实行特许经营制度,实质上造成了特许经营范围内天然气供应的垄断,成为阻碍上下游气价传导的制度壁垒。综合比较,广东对省级管网的规划定位和业务终端的管理分类更为科学,符合国家对天然气基础设施管理的精神。但广东和福建模式都存在一些过渡性的制度安排,在改革过程中需要加强区域制度和国家制度的衔接,以及省级基础设施与国家基础设施的互联互通和共享。     

基于压力敏感区域方法的供水管网漏失区域定位研究

为有效降低城市供水漏损率,快速、准确定位漏失位置,基于压力敏感区域方法,以A市为研究区域对供水管网漏失区域定位进行研究,以压力监测设备与节点漏失之间的水力关联特性对供水管网进行区域划分,建立管网漏失敏感区域,当某处发生漏失时,可立即定位到漏失区域.结果 表明,当漏失响应阈值为97％时,覆盖节点数量最多,敏感区域划分最为...     

东北亚地区跨国天然气管网分布研究

东北亚地区具有丰富的天然气资源和广阔的市场潜力，急需发展跨国天然气输配网络系统，促进这一地区能源系统的可持续发展。本文讨论了东北亚地区跨国天然气管网建设的原则，并提出该地区跨国管线走向和实施时间规划设想。本文还强调切实开拓天然气消费市场是管网系统建设的重中之重。     

计及天然气压力能的微电网储荷协调优化调度

为解决天然气输送过程中压力能的浪费问题,提高天然气能源利用率,提出将天然气压力能发电系统引入至微电网整体调度方案中。针对天然气压力能发电系统中前后端口的补热需要,将微电网中的风冷热泵补热系统与压力能发电系统进行耦合。考虑到由天然气管网中流量波动和环境因素造成的压力能出力波动问题,提出微电网储荷一体化协调优化方案,以确保系统高效稳定运行。基于上述内容,构建考虑可控电源出力成本、储能调度成本、微电网与配电网的交互成本和负荷调度成本的微电网优化调度模型,并采用Yalmip工具包编写优化调度程序。最后,通过对西南地区某调压站数据进行仿真,验证该方案的可行性与经济性。     

城市天然气中压供气输配系统有关问题的探讨

探讨了城市燃气中压供气输配系统中管网的压力级制及布置方式、调压器的选择、中压管道用材及防腐等问题。     

Failure pressure analysis of hydrogen storage pipeline under low temperature and high pressure

Low temperature and high pressure line pipes are widely used in hydrogen storage, air separation plant, liquefied natural gas (LNG) transportation etc. The material properties of pipes at low temperature are different from those at room temperature. If the medium in the pipe is corrosive, it will cause the pipe wall thickness to decrease. However, the failure pressure of the corroded hydrogen storage pipeline at extremely low temperature is lacking of adequate understanding. In this paper, we provided a novel failure pressure equation of the mild steel line pipe with corrosion defects at extremely low temperature. Firstly, a mechanical model of the line pipe with corrosion defects is established. And then, an analytical solution of the mechanical model is obtained based on elastic theory. Next, a failure pressure equation of the corroded hydrogen storage pipeline at extremely low temperature is developed. In the end, the accuracy of the failure pressure equation is verified by comparing with finite element method (FEM). The results suggest that the calculated value of the failure pressure equation is consistent with that of FEM. This paper provides a theoretical basis for the safety assessment of low temperature hydrogen storage pipeline. The new equation presented in this paper can provide useful guidance for the design of low temperature and high pressure pipelines.     

Dynamic modeling and characteristic analysis of natural gas network with hydrogen injections

With the transformation of energy structure, the proportion of renewable energy in the power grid continues to increase. However, the power grid's capacity to absorb renewable is limited. In view of this, converting the excess renewable energy into hydrogen and injecting it into natural gas network for transportation can not only increase the absorption capacity of renewable energy but also reduce the transportation cost of hydrogen. While this can lead to the problem that hydrogen injection will make the dynamic characteristics of the pipeline more complicated, and hydrogen embrittlement of pipeline may occur. It is of great significance to simulate the dynamic characteristics of gas pipeline with hydrogen injection, especially the hydrogen mixture ratio. In this paper, the cell segmentation method is used to solve each natural gas pipeline model, the gas components are recalculated in each cell and the parameters of partial differential equation are updated. Additionally, the dynamic simulation model of natural gas network with hydrogen injections is established. Simulation results show that for a single pipeline, when the inlet hydrogen ratio changes, whether or not hydrogen injection has little influence on the pressure and flow. The propagation speed of hydrogen concentration is far less than that of the pressure and flow rate, and it takes about 1.2 × 10⁵ s for the 100 km pipeline hydrogen ratio to reach the steady state again.     

天然气下游市场和终端用户定价机制亟待规范

为保障我国“十二五”的经济发展并满足节能减排的要求,需要快速拓展天然气市场.然而与世界发达国家相比,由于经济发展程度不同以及货币汇率差等原因,导致中国天然气各类下游市场用户对天然气价格的承受能力不同,上网电价和天然气价格倒挂成为天然气市场拓展的主要制约因素.掌控中国天然气上、中游的供气价格,首先要尽可能快速增加国产天然气、特别是非常规天然气的产量,以较低的价格对冲较高的进口气价;同时要掌控基于门站价的下游用户终端气价,这就需要尽可能减少从门站到终端用户的下游供气成本,而其关键在于降低交易成本.目前中国天然气下游市场存在许多亟待解决的问题,鉴于此,建议要明确各省“门站”和省天然气“门站价”的定义;“省内管网”应是省内国家主干管网与在其基础上“完善和延伸管线”的总和;省管网公司不应是一级交易平台,而是一个管理机构;规范城市燃气公司特许经营权范围,“终端大用户”和城市燃气管网终端用户适用不同的天然气价格;按照市场机制理顺天然气下游不同用户价格.如此就有可能使占下游市场份额60％的大用户市场快速开拓.     

农村生物质气化集中供气站的建设及其运营管理

结合生物质气化实际工作经验,系统地介绍了农村生物质气化集中供气站建设中经常出现的问题,以及与之相对应的有效解决方案,初步分析并提出了农村生物质气化集中供气站经济科学的运营管理手段和方法.     

A multi-objective model for optimizing hydrogen injected-high pressure natural gas pipeline networks

The paper develops a statistical model for optimizing the Hydrogen-injected Natural gas (H-NG) high-pressure pipeline network. Gas hydrodynamic principles are utilized to construct the pipeline and compressor station model. The model developed is implemented on a pipeline grid that is supposed to carry Hydrogen as an energy carrier in a natural gas-carrying pipeline. The paper aims to optimize different objectives using ant colony optimization (ACO). The first objective includes a single objective optimization problem that evaluates the maximum permissible hydrogen amounts blended with natural gas (NG) for a set of pipeline constraints. We also evaluated the variations in operational variables on injecting Hydrogen into the natural gas pipeline networks at varying fractions. The study further develops a multi-objective optimization model that includes bi-objective and tri-objective problems and is optimized using ACO. Traditional studies have focused on single-objective optimization with minimal bi-objective issues. In addition, none of the earlier research has shown the effect of introducing Hydrogen to the NG network using tri-objective function evaluations. The bi-objective and tri-objective functions help evaluate the effect of injecting Hydrogen on different operational parameters. The study further attempts to fill the gap by detailing the modelling equations implemented through a bi-objective and tri-objective function for the H-NG pipeline network and optimized through ACO. Pareto fronts that show the tradeoff between the different objectives for the multi-objective problem have been generated. The primary objective of the bi-objective and tri-objective optimization problems is maximizing hydrogen mole percent in natural gas. The other objective chosen is minimizing compressor fuel consumption and maximizing delivery pressure, throughput, and power delivered at the delivery station. The findings will serve as a roadmap for pipeline operators interested in repurposing natural gas pipeline networks to transport hydrogen and natural gas blend (H-NG) and seeking to reduce carbon intensity per unit of energy-delivered fuel.     

惠山区“煤改气”工程的调查和思考

分析了惠山区炉窑现状，指出实施“煤改气”工程存在的问题，提出了系列建议以加快推广天然气应用，改善大气环境质量。