Estimation of condensate mass flow rate during purging time in heat recovery steam generator of combined cycle power plant

Abstract

In this paper the transient modeling of HRSG (Heat recovery steam generator) in purging time was considered. In purging time, compressed air from the gas turbine was used to purge a combustible gas from HRSG. During this time; steam condensate was formed in the superheater stage which should be drained completely to avoid some problems such as deformation of superheaters. Because of this reason, estimation of drain formation is essential to avoid this problem. In this paper an energy model was provided and this model was solved by MATLAB software. Average model error is about 5%. Results show that, during purge time, steam temperature was decreased from 502 (oC) (Superheater 2), 392 (oC) (Superheater1) and 266 (oC) (Evaporators 1&2) to 130 (oC), 130 (oC) and 220 (oC), respectively and also steam pressure was decreased from 52 (bar) to 23(bar) during purge time. At end of purge time, condensate formation was about 220 (l) when inlet gas temperature was equal to 100 (oC) and purge gas mass flow rate was equal to 386.86 (kg/s).

Keywords

Dates

  • Submission Date2011-10-31
  • Revision Date2012-04-04
  • Acceptance Date2012-05-04

DOI Reference

10.2298/TSCI111031102E

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