Truck Unload Vapor to Thermal Oxidizer
Truck Unload Vapor to Thermal Oxidizer
(OP)
I have a case where a truck is loaded with a liquid product, and the vapor displaced during the fill is routed to a thermal oxidizer. A bunch of tank and truck unload station vapor lines tie into a header leading to the thermal oxidizer.
There is a discussion about whether a blower is needed in the vapor line to transport the vapor to the thermal oxidizer header/unit.
I don't think I understand why a blower would be needed in this line. Isn't the pump filling the truck with liquid providing energy to displace the vapor and push it into the thermal oxidizer's inlet header?
I haven't been able to find much information on this topic, so any guidance, references, etc. would be greatly appreciated. Let me know if you want more information on the system as well. I don't have much but I'll see what I can find.
Thanks!
There is a discussion about whether a blower is needed in the vapor line to transport the vapor to the thermal oxidizer header/unit.
I don't think I understand why a blower would be needed in this line. Isn't the pump filling the truck with liquid providing energy to displace the vapor and push it into the thermal oxidizer's inlet header?
I haven't been able to find much information on this topic, so any guidance, references, etc. would be greatly appreciated. Let me know if you want more information on the system as well. I don't have much but I'll see what I can find.
Thanks!
RE: Truck Unload Vapor to Thermal Oxidizer
RE: Truck Unload Vapor to Thermal Oxidizer
Is the problem the existing header size? Can the header be looped so it can flow either way?
More detail, better answers.
Good Luck,
Latexman
RE: Truck Unload Vapor to Thermal Oxidizer
RE: Truck Unload Vapor to Thermal Oxidizer
2/ Provide design dP across burner to assure proper mixing and therefore degree of VOC destruction.
3/ Prevent inadvertent backflow in case of hydraulic issues or operator error.
4/ Suck vapors from truck tank before filling start to avoid product swing/contamination.
5/ Hasten vapors evacuation during truck tank pressure/vacuum swing inerting.
6/ Provide ventilation of piping low points and pockets to avoid stagnant conditions and undesired polymerisation, condensation etc.
Vapors are hard to be controlled and those not always want to go to a point it was intended. There are many hidden&sudden events that have a potential to force a system work another way it was designed/intended/considered with no a clear evidence to operator. A pressure changer (e.g. blower) will help to control flows.
RE: Truck Unload Vapor to Thermal Oxidizer
The key issue as my fellow posters have stated is what is the MAX pressure allowed in the tank truck?
Often this can be very low pressure - think low inches of water column. Hence there is very little pressure to flow the gas to the burner which will have a pressure requirement of its own.
The vent headers are often large to allow this flow.
So find the lowest tanker pressure at the facility and that will give you an idea of how much or little pressure is available.
Blowers though have a risk of implosion of trucks so need to be designed very carefully to avoid this.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Truck Unload Vapor to Thermal Oxidizer
We will be getting a better picture of the existing vent header system in terms of layout, flows, pipe sizes, etc., and will be getting fan curve(s) for the thermal oxidizer.
For the truck loading line of interest, we should also be getting more information on layout, in-line losses, and truck max pressure. There is a vacuum relief valve set at five inches of water column, to be installed in the vapor vent line.
Thanks again for all the reasons why a blower can be useful, I am hopeful that digging deeper into the gas pressure/flow calculations of the system will help too.
RE: Truck Unload Vapor to Thermal Oxidizer
RE: Truck Unload Vapor to Thermal Oxidizer
Physical strength is different to internal pressure. Often the issue is not the tank itself, but all the connections. But even a few psi when there are thousands of square inches available, rapidly add up to a lot of force.
Tankers like LPG are rated for pressures up to 25 bar, but most tankers are I suspect "atmospheric" pressure, a bit like large storage tanks.
Bit difficult to find a definitive source, but 0.2 to 0.4 bar or 4 psi for "normal" liquids seems to crop up a lot. So maybe a bit more than "inches of water", but start low and go up when it comes to tanks.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.