Side Stream Strippers

Sometimes the cheapest way to correct a hydraulic problem on a side-stream stripper is to pump the product into the stripper. I have modified several plants in this way, with excellent results. 

Side-stream stripper A and C as before, but B as bottoms of side stripper. 

Fractionation Section. A typical fractionation section includes the coker fractionator and attendant heat exchange equipment, the light gas oil side stream stripper and the overhead system. The coke drum overhead vapors enter the fractionator under shed trays which are located below conventional wash trays. Hot induced gas oil reflux is pumped to the wash trays to condense recycle and to wash the product vapors. The light and heavy gas oil products are condensed as sidestream products. The light gas oil product is usually steam stripped in a sidestream stripper. The overhead vapors from the fractionator are partially condensed and the gas and gasoline products are directed to the vapor recovery unit. 

Side-stream rectifier Side-stream stripper... 

Side-stream strippers are common in refinery fractionators. The control system depends on whether the stripper feed is withdrawn from... 

Figure 19.11 Side-stream stripper control, (a) Total drawoff (6) partial drawoff. (Concept based on N. Lieberman, Chemical Engineering, September 12,1977.)...

IV. Distillation with Liquid Side Stream Stripper... 

Glinos, K., Malone, M. F. (1985). Minimum Vapor Flows in a Distillation Column with a Side Stream - Stripper. Ind. Eng. Chem. Process Des. Dev., 24, 1087-90. 

A side-stream product drawn from a crude tower is only half fractionated. Refluxing below the drawoff tray controls the product end point. Front-end fractionation takes place in the side-stream stripper. 

I found that the instrument air tubing connection to the kerosene-draw control valve was loose. That valve controls the flow of kerosene from the crude tower to the side-stream stripper. The control valve simply wasn t getting enough air to open fully. I tightened the connection, and kerosene production rose to the normal rate. 

Lube distillates are sent at their bubble points to side stream strippers. Steam is injected, reducing the partial pressure of hydrocarbons which effectively removes lighter hydrocarbons improving volatility beyond that obtainable without side stripping. Ten to thirty percent of the stream may be removed in the stripper. If the heavier streams are not stripped this will reduce the yield of lighter lubes. Stripping is an important part of the overall operation to achieve the best separation and produce the desired products. A stripper typically consists of 4 to 6 sieve trays but packing may also be used. 

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