Tank cleaning and Degassing
RAFIBRA, offers as one of its services, the Clearing and Degassing of the Liquid Petrol Products Tanks.
Degassification is made in order to reduce the amount of combustible toxic vapours and fumes, on levels under of the Lower Explosiveness Limit (L. I. E.) There is an appropriate degassification when the content of toxic fumes of the inner atmosphere of the tank is under the 20 % of the L.I.E.
Due to the restlessness that we had with the former tank degassing methods used, due to the high risk of explosion as atmospheric contamination that these procedures entail mainly because the vapours and fumes are poured directly in the air, RAFIBRA has developed a new method that reduces these risks in more than a 95 %.
Historically, there have been only two ways for degassing tanks:
- a) The first one, sucking the vapours and driving them outside, but the main problem of this method is that is very dangerous when the vapours pass through de mobile organs of the sucking pumps, even if the pumps are EEX.
- b) The second one, consisted in adding an entrance hose, and introducing forced air, driven trough pipes into the tank with a turbine. These toxic vapours and fumes were spilled to the atmosphere, and being heavier than air, were floating on the floor, with a high risk of explosion.
The new procedure designed and patented by RAFIBRA, uses a new degasification methodology based in catalyzed condensation of COV’S, that capsulate the vapour molecules and precipitates them to the floor, creating a layer on the surface that prevents new volatile elements to form; with this method the time for the degassing is reduced from three hours to twenty minutes, and also is reduced the danger of this operation.
The other great advantage is that the access to the tank and the collection of the hydrocarbon sedimentation mud are made in safe conditions, because the tenso-activated layer of the surface of tank floor avoids volatile elements to form.
The system used by RAFIBRA for degassing tanks is a RAFIBRA patented procedure with the advantage that reduces the explosiveness risk in a 95 % y avoids spilling the toxic fumes and vapours on the atmosphere, fulfilling Spanish and European rules.
The resulting liquids of the clearing are canned in the appropriate containers, in order to transport them to the waste elimination plant.
As well in this operation as after sucking the remaining fuel inside the tank, the fall of the explosiveness index is verified.
All the ventilation equipment is connected to the ground, jointly with the tank structure.
Oxygen is not allowed in any case to ventilate the tank.
Access to the tank
In any case is allowed to access or stay inside a tank until the light hydrocarbon content in the tank atmosphere is under the 20% of the L.I.E.
The technicians that get into the tank, shall be provided of the following equipment:
- Cotton underwear.
- Cotton or neoprene overall.
- Log neoprene boots.
- Gloves, accreditted for working with this kind of products.
- Possitive air pressure mask. The air source must come from vapours free zones.
- Harness and safety ropes, outer hooks, and rescue equipment.
- Explosiveness-meter, with direct reading and acoustic signal, connected all the time.
- And all the necessary to perform our labours in maximum safety conditions.
Information on access
The access and stay of people inside the tank, in the above mentioned conditions, will be always under surveillance from outside, ready to make the evacuation. The access inside the tank will be made with non sparkling equipment (aluminium stairs, with rubber endings, etc…) and always, making possible a fast evacuation.
El acceso al interior se hará con equipos que no provoquen chispa (escalera de aluminio, con topes de goma, etc.) y deforma que siempre sea posible una evacuación rápida.
The lighting equipment shall be flameproof and with a connection under 24V.
When removing the tank surface muds, it shall be done very carefully, because the explosive atmosphere forms again. All the precautionary meassures, stated above shall be kept, and, if necessary, the degassification shall be repeated.