Sour Water Stripping Unit

Ammoniacal water streams from various refinery units are mixed and cooled with cooling water in E-101 to approximately 120°F (see Figure 9-9). The cooled effluent is degassed in V-101. The gases evolved are sent to flare. The degassed foul water is pumped by P-101 to tank TK-101 and kept under fuel gas blanket. Sufficient detention time is allowed in this tank to separate out traces of oil in the water. Separated oil is skimmed off with a swing arm suction line and sent to the slop oil system. The water is pumped to steam stripper column V-103, with about 40 sieve plates.

Ammonia and H2S are stripped from this water in column V-103, with 40 plates. The column has a thermosyphon reboiler E-104, heated with 150psig steam. Feed before entering the column is heated to approximately 205°F by heat exchange with the V-103 bottom stream in E-102 and feed enters the column V-102 at the 30th plate. To provide reflux to the column, a sidestream is withdrawn from the 34th plate, cooled to 150°F from 195°F and returned to the top plate of the column. Column top pressure is maintained at 15psig. The top vapor distillate containing most of H2S and NH3 is sent to sulfur plant or flare. The bottom product, stripped water at approximately 262°F, is first cooled to 175°F by heat exchange with incoming column feed. It is next cooled in air cooled exchanger E-105 then in trim cooler E-106 to 105°F before sending the stream outside the battery limit.

The operating conditions of a sour water stripping unit are shown in Table 9-11. The unit utility consumption and yields are shown in Tables 9-12 and 9-13.

TO FIARE FOUL WATER FOUL WATER

STORAGE TANK STOPPER

TK-101 V-103

Battery Limit

Table 9-11

Sour Water Stripper Operating Conditions

Table 9-11

Sour Water Stripper Operating Conditions

PARAMETER

UNIT

STRIPPER FEED TEMPERATURE

°F

205

STRIPPER TOP TEMPERATURE

°F

175

STRIPPER TOP PRESSURE

psig

15.3

STRIPPER REBOILER TEMPERATURE

°F

262

STRIPPER BOTTOM PRESSURE

psig

32.0

TOTAL NUMBER OF PLATES IN STRIPPER

40

NUMBER OF PLATES ABOVE FEED PLATE

10

REFLUX RATIO, REFLUX/FEED

3.13

REFLUX TEMPERATURE

°F

150

STRIPPED WATER DISCHARGE TEMPERATURE

°F

105

Table 9-12 Sour Water Stripper Utility Consumption per Ton Feed

UTILITY

UNITS

CONSUMPTION

STEAM

mmBtu

0.345

ELECTRICITY

kWhr

2.73

COOLING WATER

MIG*

0.135

*MIG= 1000 IMPERIAL GALLONS.

*MIG= 1000 IMPERIAL GALLONS.

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  • theodore
    How do you flare sour water stripper units?
    4 months ago

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