Abstract

Storage tanks (Crude Oil/Oil water/Brackish water) in Kuwait oil Company are lined with fiberglass lining over the bottom plate for internal corrosion protection and to minimize the problem of exterior corrosion by providing enough strength to bridge small perforations.

Storage tanks undergo major survey &maintenance activities on regular intervals and during maintenance period the fiberglass lining on tank bottom plate need to be removed to inspect and assess the condition of bottom plate. The removal of lining used to be carried out by manual method in which contract personnel enter the tank and remove the lining by continuous hammering, using hammer and chisel.

Manual removal method has the difficulties like the activity takes longer duration (2-4 months), high number of workers (15-25) working inside the tank, health and safety issues like working in a difficult posture like crouch down low and doing hammering leading to fatigue, exposure to hammering noise, grit blasting dust and fibre glass dust affecting the health of the workers, probability of injury due to hammer blows and flying fibre glass chips. In addition, after the manual removal of lining we have to carry out grit blasting of the surface for inspection and many times the tank bottom surface was found having mechanical damages due to the hammer and chisel blows.

Hydro jetting technology was introduced recently to remove the finer glass lining and found having many benefits like duration reduced to one third, reduced number of workers (3-4 personnel) required during execution (leading to considerable reduction in man hours), elimination of all the health/safety hazards as that of manual method, the tank surface was ready for inspection after the hydro jetting (unlike manual method where grit blasting was required after the lining removal) and no damages observed on tank bottom surface.

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