The Atmospheric and vacuum distillation unit is a crude oil primary processing unit that separates various fractions in the crude oil by distillation. When the Primary distillation column is not used, the feed volume of the Atmospheric furnace is the treatment volume of the refinery. Therefore, the thermal load of the Atmospheric Furnace is the largest in the refinery.
When the crude oil is heated to 400 ℃, it will crack under normal pressure which affects the product quality. Therefore, the outlet temperature of the Atmospheric Furnace is generally 360℃ ~ 370℃.The inlet pressure of the Furnace is generally about 0.08 MPa.
Since the feed volume of the Atmospheric Furnace is large and liquid phases, the furnace tubes are often connected in multi-pass parallel connection. Usually, valve restraint or instrument control is adopted to ensure uniform flow and heating temperature in each process. Bias flow will cause thermal deviation and cause coking of the furnace tube.