Q & A > Question Details
Is there any non-manual method for cleaning tanks used for asphalt storage? We dilute as much as possible with recirculating hot HVGO, but we have to finish the job removing a several inches layer of sticky asphalt.
28/04/2008 A: Marcello Ferrara, ITW SrL, mferrara@itw.it
We have developed a non-entry chemical cleaning method.
We use patented and well proven asphaltene stabilizers, which turn the sludge into a fully reusable product.
25/04/2008 A: Alan Goelzer, Jacobs Consultancy, alan.goelzer@jacobs.com
Best wash liquid is actually hot FCC slurry oil [also known as decant oil]. Most FCC slurry oils are highly enriched in polynuclear aromatics and these are good solvents for the very heavy polynuclear aromatics and asphaltenes present in asphalts. Unfortunately, there will be some dirt + gum/sludge + soot + condensed graphitic components and these are far less likely to become dissolved in hot FCC slurry oil. So it still can be necessary to scrape out the remaining carbonaceous + inorganic layer.
25/04/2008 A: Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
If the sludge is very compact typically in a tank with a volume of 70 m3 and say about 350 drums to be disposed of, chemicals can be used with closed manways. Chemicals can be introduced into the tank adding a carrier to ensure contact with the chemical throughout the sludge.
This is followed by a water washing phase with another chemical.
The tank is the recirculated for about 2 weeks and should, after opening of manways solubilized the original sludge. All in all only 2 drums of solids will require disposing at the end of the cleaning.
Cleaning is performed at ambient temperature of 12-15°C, agitation is smooth as only recirculation with transfer pump needs to be performed.
25/04/2008 A: SImone Robinson, Tube Tech International Ltd, simone@tubetech.com
Greatly appreciate the difficulty caused by the 'stickiness' of the asphalt. There are a number of non-man entry systems which can be used to clean asphalt storage tanks. We have recently cleaned a 12m high x 6m wide bitumen tank within 3-4 days using unique non-man entry cleaning systems. For IP reasons I cannot detail the systems we use but the answer to your question is a resounding 'yes'.