Flow atmospheric distillation unit

Figure 2.4 Typical flow of refinery atmospheric distillation unit.

Figure 3-1. Flow diagram of atmospheric and vacuum distillation units (1,3) heat exchangers (2) desalter, (3,4) heater (5) distillation column, (6) overhead condenser, (7-10) pump around streams, (11) vacuum distillation heater (12) vacuum tower.

Figure 1-11 General flow diagram for a distillation section (atmospheric and vacuum), including a primary flash unit, in a refinery. 

The processes used in industrial air-separation plants have changed very little in basic principle during the past 25 years. After cooling the compressed air to its dew point in a main heat exchanger by flowing counter current to the products of separation, the air feed, at an absolute pressure of about 6 MPa, is separated in a double distillation column. This unit is kept cold by refrigeration developed in a turbine, which expands a flow equivalent to between 8 and 15% of the air-feed stream down to approximately atmospheric pressure. 

It consisted of a single-pass, five-plate, water-cooled condenser capable of independent flow and temperature control. Heat was supplied to the evaporator reservoir, so that it could be operated at selected temperature levels. The rotating assembly, consisting of a shaft with spacers capable of accepting six disks 12 inches in diameter, of varying thickness and composition, was equipped with a variable speed drive. With the arrangement shown, approximately 2 sq. feet of disk-condenser surface area was available for mass transfer. Tests were performed on this unit at atmospheric pressure, using city water (125 p.p.m. of dissolved solids) as feed, to determine the effect on distillation rate of (1) reservoir tem-... 

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