Novel high temperature steam transfer pipes

这项可行性研究涉及提高核能和化石燃料发电中使用的蒸汽循环的效率。目前，蒸汽是使用钢管输送的，钢管将蒸汽的温度限制在不超过640摄氏度。为了提高效率，建议发电厂在蒸汽温度可能高达760摄氏度的情况下运行。使用传统的蒸汽循环设计，这样的温度将需要使用镍基合金。这些合金比钢更昂贵，而且供应稀缺，考虑到全球新发电厂的需求量，本可行性研究提出了一种替代工厂设计，该设计将允许钢制蒸汽管道在比目前高得多的温度下运行。建议的设计是一个管道与陶瓷隔热涂层（TIC）在其内表面和冷却其外表面提供的废气蒸汽从高压涡轮机。三个机构将在这项研究中合作：布里斯托大学，克兰菲尔德大学和诺丁汉大学。每个机构将调查一个中心的技术挑战，必须克服之前，替代工厂的设计可以被认为是可行的。布里斯托将开发拟议的蒸汽循环的热力学模型。该模型将计算过热蒸汽通过TIC进入钢管的热传递速率，然后计算返回锅炉的再热蒸汽的热传递速率，该再热蒸汽用于冷却蒸汽管。与传统设计相比，该模型将预测蒸汽管道内的最高温度和工厂的效率。克兰菲尔德将在超超临界温度下对候选TIC材料在蒸汽中进行腐蚀测试。腐蚀试验的结果将用于估算TIC在发电环境中的使用寿命。诺丁汉将调查涂层和钢管的结构完整性。在启动、唐斯和稳态运行期间，TIC和钢中将产生应力。这些应力在性质上与常规蒸汽输送中的应力大不相同。诺丁汉将使用现有的TIC和钢的性能计算模型来预测它们在实际运行条件下的寿命。该可行性研究的结果将是对先进电厂管道工程中使用镍基合金的替代品开发机会的评估。

This feasibility study concerns improving the efficiency of steam cycles used in nuclear and fossil fuel energy generation. Currently steam is transported using steel pipes which limit the temperature of the steam to no more than 640 degress C. To improve efficiency, power plants are proposed that will operate with steam temperatures possibly up to 760 degrees C. Using conventional steam cycle design, such temperatures will require the use of nickel-based alloys. These alloys are more costly than steels and are in scarce supply, considering the quantity required for new power plants worldwide.An alternative plant design is proposed in this feasibility study that will allow steam pipes made of steel to be operated at much higher temperatures than at present. The proposed design is of a pipe with a ceramic thermal insulation coating (TIC) on its internal surface and cooling on its outer surface provided by exhaust steam from the high pressure turbine.Three institutions will collaborate in this study: the University of Bristol, Cranfield University and the University of Nottingham. Each institution will investigate a central technical challenge that must be overcome before the alternative plant design can be considered viable.Bristol will develop thermodynamic models of the proposed steam cycle. The model will calculate the rate of transfer of heat from the superheated steam through the TIC into the steel pipe, and then the rate of heat transfer to the reheat steam returning to the boiler being used to cool the steam pipe. The model will predict the maximum temperatures within the steam pipe and the efficiency of the plant, compared to that of a conventional design.Cranfield will carry out corrosion testing of candidate TIC materials in steam at ultra-supercritical temperatures. The results of this corrosion testing will be used to provide estimates of the lifetime of the TIC in a power generation environment.Nottingham will investigate the structural integrity of the coating and the steel pipe. Stresses will be generated in the TIC and steel during start-ups, shut downs and steady state operation. These stresses will be very different in character from those in conventional steam transport. Nottingham will use existing computational models of the properties of TIC and steel to predict their lifetime under realistic operation conditions.The outcome of this feasibility study will be an assessment of the opportunity for the development of an alternative to the use of nickel-based alloys for pipework in advanced power plant.