1.2E-04 1.2E-04 1.3E-04 1.1E-04 1.1E-04 1.3E-04
1.0E-04 9.5E-05 9.0E-05 17 / 2 2 4 /2
3/3
10/3 17 / 3 24 / 3 3 1 /3
7/4 1 4/4 21 / 4
Date
system are shown in Figure 5 . The image on the left shows a sample of the inlet, which contains hydrocarbons and solid particulates. In contrast, the image on the right is taken from the water outlet and shows only a clear water phase. The performance evaluation successfully demonstrated that heat exchanger fouling was mitigated immediately upon start-up of the hydrocarbon and solids removal system. Hydrocarbon recovery was demonstrated, and the customer validated the filter changeout frequency as reasonable and acceptable, i.e., the solid particulate filters did not have to be changed out more often than expected. The Torsep system was so successful that the refiner is purchasing the rental system. In conclusion, this article illustrates a technique that can allow sour water stripper units to effectively remove solid and hydrocarbon contamination, thereby allowing the stripper columns to operate as designed, without exchanger fouling and likely without hydrocarbon excursions to the sulphur recovery unit. *1: Some charts and figures were edited from this article for want of space and are available on request. Endur Tetra, Envision, and TORSEP are marks of Transcend Solutions. Figure 5 Left: inlet to system; right: water outlet from system
and the valve percentage open as a column graph. The left axis represents the boot interface level, while the right axis indicates the valve percentage open. In operation and as seen in this plot, the oil level in the boot builds until it reaches 80%. At this point, the valve opens, and oil is drained from the top of the boot. The frequency of oil dumping is not consistent but is seen multiple times. An ‘upset’ condition was seen between 25/3 and 27/3, when the valve was fully open, and the oil level dropped below the 80% mark. The refiner has not shared an explanation for this upset. Typical process upsets in sour water systems have been previously noted to be related to level control failures, turnarounds, power failures, and weather, among others. Filter changeout frequency The solid separator elements were changed out on average every 10 days since February. The coalescing separator elements were changed out once since start-up. This changeout frequency met the expected target, and the customer is satisfied. Recovered hydrocarbon The recovered hydrocarbon is seen as a pale yellow, clear liquid. *1 Its boiling range was determined by simulated distillation. *1 The boiling range extends from 80-700ºF. The specific gravity was measured at 0.8. Summary In summary, a picture is worth a thousand words. Samples taken from the inlet and outlet of the Figure 4 Differential pressure normalised for flow (dividing by the square of the flow in gpm)
VIEW REFERENCES
Mathews Thundyil matt.thundyil@trnscnd.com David Seeger dave.seeger@trnscnd.com Arvind Chaturvedi arvind.chaturvedi@trnscnd. com
Refining India
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