Transient thermo-mechanical analysis of steam generators for solar tower plants Articles uri icon

publication date

  • February 2018

start page

  • 1051

end page

  • 1068

volume

  • 212

International Standard Serial Number (ISSN)

  • 0306-2619

Electronic International Standard Serial Number (EISSN)

  • 1872-9118

abstract

  • In solar power tower plants, fast start-ups and/or load changes are mandatory to increase the power plant dispatchability. The high temperatures of the working fluids and the partial-load operation will reduce the lifetime of the thick-walled components at the steam generator. Therefore, a proper heat exchanger design should consider the stress evolution during the transient operation of the plant. This work addresses, for the first time, a methodology to determine the dynamic behavior of all heat exchangers of a steam generator train. The methodology proposed here is a powerful tool for the design of solar power plants. The stress analysis model identifies the most important components of the steam generation train during transient operation. The methodology consists of the combination of analytical models to obtain the coupled response of the steam generation train from the following dynamic variables: temperature, pressure and stress. An example of this methodology is presented for two start-up initial conditions: the assumption of non-isothermal and isothermal temperature profiles of the heat exchangers. A steam generator train based on conventional shell and tube heat exchangers is analyzed. The analysis shows that the non-isothermal condition takes approximately 50 min to reach nominal conditions, whereas the isothermal condition takes approximately 110 min, requiring 600 tons and 716 tons of hot salt to perform the start-up procedure, respectively.

keywords

  • solar power tower plant; steam generator; start-up procedures; thermal stress analysis