Phase cooling method is one of the start-up operating force methods of the air separation plant which uses switching heat exchanger to self-remove moisture and carbon dioxide. In the full low pressure air separation plant, under the operating pressure of 0.5MPa (surface pressure), the moisture content is-40 ~ -60℃ has been basically frozen. However, carbon dioxide will not be precipitated and frozen until it is below-133 ℃ until-165 ~ -170℃ frozen. Thus, the range from-60℃ to-133 ℃ is dry zone. Using this principle, the cooling process of the equipment during the start-up operation is carried out in stages, which is the stage cooling method. The whole cooling process is divided into four stages: the first stage is the stage of moisture precipitation and freezing. In this stage, only the switching heat exchanger is first cooled until the temperature at the cold end reaches-60℃; the second stage is drying stage, and the available water has been cleared, while for the machine which has...
Oct 18, 2023