Abstract: The operating characteristics of the direct aircooled steam condenser were analyzed. Taking two units as examples (there is ash deposition in the fin tube's face of one unit, and the other unit is clean.), the variation law of the parameters of each area of the aircooled condenser with ash deposition in partial area was obtained by theoretic calculation.The results show that the effective heat radiation of the direct aircooled condenser with ash deposition is decreased, and the amount of the condensed steam is also decreased. Along with the increase of the ash deposition in the dirty unit, the heat radiation and the amount of the condensed steam of the clean unit increase gradually, and the air temperature rise also increases obviously.

Key words: direct air-cooled steam condenser, ash deposition in partial area, temperature rise, amount of condensed steam