Installation and use of vent valve on gas station fuel tank vents
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There is one vent on each gasoline tank at a gas station. Why are flame arrestors not required on the vents of some tanks, while they are necessary for the vents of other tanks? Why is the shut-off valve on the vent port of the flame arrestor set to be normally closed, while the shut-off valve on the vent port of those without a flame arrestor is set to be normally open? Why isn’t a shut-off valve installed on the vent port of the diesel tank? I’m begging all the experts here to explain this to me, a complete novice in hazardous chemicals: D
Is this post going to be deleted? . . .
Hey, folks who are passing by, take a look – this post needs your help :(
Gasoline requires a flame arrester, while diesel does not. The valve should be kept in the open position
I also want to know why? Could someone who is passing by help answer this?~~~
In this diagram, there are three breather valves and one vacuum pressure valve; the vacuum pressure valve opens to allow emergency pressure release once a certain pressure (2000 Pa) is reached. Nowadays, three-stage oil and gas recovery systems are used, and with such systems, there is no need for pressure valves anymore – a flame arrestor vent cap can be used instead for releasing gas. This diagram is quite old; it probably does not show three-stage oil and gas recovery, or the pipes might be buried underground
The opening of the pressure valve means that the oil and gas no longer flow through the three-stage oil and gas recovery system
In accordance with the requirements of 6.3.9 and 6.3.11 in standard GB50156-2021, the vent pipes for gasoline and diesel must be installed separately. Gasoline vent pipes with vapor recovery systems need to be equipped with flame arresters and breather valves. Generally, the gasoline vent pipes are shared; two vent pipes are used, one as the active one and the other as a backup. Those with normally open stop valves and breather valves are the regular vent pipes, while those with normally closed stop valves and flame arrestors are the backup vent pipes. Since there is no spare diesel vent pipe, there is no need to install a shut-off valve.
According to Article 6.3.9 of GB50156-2021, \"a flame arrester shall be installed at the outlet of the vent pipe.\" Diesel fuel should also require a flame arrester – why isn’t one used?
That’s a great question. Please give it some support; I hope the experts here can offer some advice!