Crude tower

TABLE 13-27 Light-Component Analysis and TBP Distillation of Feed for the Atmospheric Crude Tower of Fig. 13-94... 

Example 9-8 Heavy Gas-Oil Fractionation of a Crude Tower Usu Glitsch s Gempak (used by permission of Glitsch, Inc. Bulletin 5140)... 

The heavy naphtha-Ught gas oil fractionation zone of a crude tower has to be revamped to handle 25% more capacity. Because trays would be working at high percent flooding, Gempak structured packing is condensed (Figures 9-56A-D). 

Pressure drop for both AS (0.5-in. crimp height) and AS (0.375-in. crimp height) packings is acceptable for the crude tower operation. 

How many theoretical contact stages are required for a side reflux system on an atmospheric crude tower The vapor is to he cooled from 500°F to 440°F the circulating... 

The operation of the main column is similar to a crude tower, but with two differences. First, the reactor effluent vapors must be cooled before any fractionation begins. Second, large quantities of gases will travel overhead with the unstabilized gasoline for further separation. 

Even if the governor-steam inlet control valve is 100 percent open, it may still be possible to increase the supply of motive steam into the turbine. The position of the governor when it is wide open can often be reset to admit more steam flow. I once increased the flow through a crude tower-bottom pump by pushing hard against the base of the governor, and forced it to actually open to its maximum position. The pump speed came up 300 rpm, and the flow increased by about 15 percent. 

Changes in the crude tower cut temperatures, between reforming, hydrocracking, and FCC feeds. 

Atmospheric crude tower, naphtha/light fuel oil (LFO) fractionation section. 

Atmospheric crude tower, kerosene/gas oil fractionation section. 

Atmospheric crude tower, gas oil/resid fractionation section. 

To improve the stage distribution for each section in the crude tower, the tower is decomposed into a sequence of simple columns as a first step. After that, the ideal number of stages and the optimum feed stage for each simple column are found. Finally, the simple columns are merged back to the complex column with new numbers of stages for each section. 

Computer modeling of the crude process is worthwhile for many reasons including 1) initial design 2) economic optimization of operation and 3) control and adjustment of product compositions and operating costs. The first models were based on reducing the process to a combination of two-product distillation calculations because of the available computer power. More recently, the computer calculation is able to handle the crude tower as is however, the two-product combinations are useful to guide technical supervision of the operation (Figs. 4 and 5). 

The results of test runs or of computer modeling the separations in the crude tower system are represented as stream compositions in Fig. 6. 

McNulty, K. J. and Chatterjee, S. G., Simulation of Atmospheric Crude Towers Including Packed Bed Pump-around Zones using a Rate-based Simulator, The Institution of Chemical Engineers Symposium Series No. 128, Distillation and Absorption 1992, A329-A344 (1992). 

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