Incident Report

Subject:                    Crude Tank - Roof Problem    

Date of first enquiry:                 Monday, January 06, 2003            

Initial enquiry / comment.

Kevin,

I have a crude oil floating roof tank problem. Pls pass on to others who might be able to help. Problem: Suspect one or more of several pontoons holding up the roof is leaking. This has led to crude oil surfacing to above the roof.
Immediate measures taken: We use an air-operated pump top eriodically pump off the oil from the roof via the roof drain outlet back into the tank.

However the "leaking" oil keeps re-surfacing on to the roof.
Question: Does anyone know of any preventive measures that can be taken to prevent the oil on the roof to be ignited by lightning ? The oil on the< /SPAN>roof appears in patches but tend to move towards the roof centre.
With our tropical thunderstorms, the threat of a lightning strike on the hydrocarbon vapour is always there. We are looking for temporary measures until we can decommission the tank to repair the leaky pontoon. Are there chemicals that can be sprayed on to the roof deck to prevent this ? Foam is a possibility but we all know that foam degrades and goes off after a while.
Regards,

Responses:

Date

Detail

Documents
Mon 06/01/2003 14:11
I can suggest two ways of reducing the risk.
Angus manufactures a product called VSA (Very Stable Alcoseal?) which consists of an additive, mixed with alcoseal concentrate that will give you a much longer lasting foam blanket. Yes, you will have to replenish the blanket regularly, but it supersedes normal foam blankets life span by far.
Secondly you can go the "Hazmat route" and cover the roof with an absorbent that will not only absorb any oil but also reduce vapours. Again your Hazmat Suppliers will be able to recommend the correct product and application.
Regards and all the best for 2003
  

Mon 06/01/2003 17:31

Using foam is only a short term solution. What you may want to consider is using a Foam.Emulsifying solution. That can be a product such as a detergent or a fire product such as Micro Blaze Out. This is not a fire fighting Foam but is listed by UL as a surfactant. It will emulsify the hydro-carbon and make it non-flammable. I am not sure exactly what percentage you will have to reach, but it will require less agent than foam and last longer. Once the crude is emulsified it will stay that way for a long period of time.

The problem of contaminating the crude in the tank would be minimal due to the quantity of product contaminated by the foam surfactant verse the total quantity in the tank if it was pumped back into the tank.

  
Thu 16/01/2003 01:20

We have decided on trying to keep the leaking pontoon(s) afloat by placing empty plastic jerry cans into the pontoon compartment. We will pack in several of these jerry cans to minimise space for the oil to enter the pontoon compartment as well as provide the flotation and even up the roof and prevent potential tilting of the roof. This work will be done when the roof is high. Hopefully this will work and little oil will surface on to the roof after that. The plan is to repair the pontoon leak at a later suitable time.

Having said that, I am interested to know who makes or supplies this Micro Blaze Out that you mentioned. Appreciate you giving me the contact address, or related details if available.