The C3, C4s and some C5 (up to 2mol%) have a molecular weight heavier than air. So, if there is not a ventilated area, this components will stay over the floor.
I know that a manual shutoff valve in the pipe connection should be provided between the tank and each liquid or vapor header. These...
Hi,
We have some flange connections within the LPG Storage bunded areas. This is to, in case of leaks the LPG will stay inside the bund. In the event of fire in such a bund, these flanges would be vulnerable to opening, and provide additional flammable material to the fire.
However some people...
Thanks IFRs,
Just one more question:
According your post of 17 Jul 09 10:46, you said:
"3) Since the flash point is less than 100 DegF, flame arrestors are required on open vents...."
And, in your last post you stated that "the circulation vents are open vents".
So, in order to have a clear...
The API STD 2000 indicates:
"4.4.1.2 ...A flame arrester is not consider necessary for use in conjunction with a PV valve venting to atmosphere because flame speeds are less than vapor velocitiesacross the seats of PV valves."
"4.4.1.3 Open vents with a flame-arresting device may be used in...
Thanks for the comments.
So, we can say that:
1. If the tank has peripheral circulation vents (that are in the top of the cilinder or shell), and has the vent on the fixed roof, then there is no need of P-V valve or N2 blanketing.
2. If we decide to close the peripheral circulation vents and the...
Hello,
We have an internal floating roof tank of capacity 3500 barrels and we need to use it for storage of Anhydrous Ethanol.
This tank already has air circulation vents provided on the fixed roof which is above the internal floating roof for breathing in and out during product movement.Also...
Ok. Thanks for your comments. I think that given the small flow of vacuum off-gas is enough to put one block and one vent valve.
Also, what about the fuel gas that goes to the pilots (ignitor)? Is it valid to put the double block and vent valves up stream the interconection between the main fuel...
Hello,
I know, according to NFPA 86 (Ovens and Furnaces) that we need to install a double block and vent on-off valves in the pipe of fuel gas that will be burned in the heater. That is what we have for Fuel Gas.
But, in adittion, we also burn some sour gas (independent pipe to burner) from the...
Hi,
I have been checking the historical trend (from 2002 to 2008) about the differences between cracked naphtha final boiling point and light cycle oil (LCO) initial boiling point and I found that always the Naphtha End point is lesser than the LCO IBP.
I want to know if this is normal. If is...
Hello!,
Our jet fuel tanks (atmospheric) have circular manholes on the roof (flange covers of 24” diameter). We need to convert them from flange covers to hinged covers in order to facilitate the inspection (through them) of the floating suction pipe (according with API 653, in the Inspection...
Hi,I would like to know about the AIT (autoignition temperature) of heavy cracked hydrocarbons (from a thermal conversion like Visbreaking resid). I was looking for in the NFPA 325 but I have a doubt. I think that the AIT of the Visbraking resid is less thatn the AIT of vacuum or atmospheric...
Thanks for your comments. Related if the deck is simple or double, would you specify the standard that mention it?
I mean, single deck roofs shall not be fitted with emergency drains. And, in addition to normal roof drains, double deck roofs shall be fitted with emergency drains, capable of...
Hello!
I know that in an external floating roof tank, the minimum-size primary roof drain shall be capable of preventing the roof from accumulating a water level greater than design at the maximum rainfall rate. Normally this primary drain is placed in the central point of the roof and it can be...
Thanks for the comments,
I think there is some guidelines that are normally employed by the designers. For example 75% max. of jet flood is usual. But that value will depend of the kind of column that we have.
In our case, if we design a new column naphtha splitter, the maximum jet flood would...
Hello,
Do you know what is the recommended jet flood for the following column?
Naphtha Splitter: the gasoline from crude distillation column would go to an splitter, (TBP cut : 95ªC).
We have an existing column, so, I think there is a minimum and a maximun jet flood to consider for reusing...
Thanks Montemayor and sshep for your comments.
The fresh caustic is at 20°Baumé and 25°C. Part of the pipe is installed at the side of the traffic areas and part is over the traffic areas.
I know that units like Alkylation contain most of the piping carrying Sulfuric acid or Hydrofluoric acid...
Hello,
I want to know if somebody knows about installation criteria for piping carrying caustic. I mean, if there is any rule forbidding the layout of caustic lines on the piperack.
I believe that installing the piping at grade is dangerous not only because of the tripping hazard it creates but...
That's right IFRs. The existent tank is an external floating roof. When i said "the roof "clogging"", I was trying to said that for some reason, mechanical reason, the roof will not go up or not go down with the fluid pumping into or out the tank. So, with that scenario, if the fluid is pumping...
Ok Luis,
You're right the API 650 section that you've mentioned I think it means to put vents under the floating roof.
What about the NFPA 30 ? In point 4.2.5.2.2 says: "For vertical tanks, the emergency relief venting construction shall be permitted to be a floating roof...."
Regards
