Torch backpressure
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The back pressure of the flare system is 0.1 Mpa(g); does this refer to its maximum pressure, that is, the pressure when all devices are releasing gas, or is this the pressure that the flare system operates at under normal conditions?
Personally, I think that this is the pressure the torch system operates at under normal conditions. If it’s not positive pressure, won’t the outside air flow into the flare pipeline? Then, bang~
I’ve never seen a torch with such high back pressure. As far as I know, the back pressure of the torch is generally caused by the presence of a water seal, and it is directly related to the height of this water seal. What is the back pressure if it’s 0.1 MPa, with a 10-meter water seal?
When calculating the discharge flow rate for emergency release of the device, it is necessary to set the back pressure of the gas pipeline system. It can be set to this pressure (depending on the distance from the flare). When it actually reaches below the torch tip, a water seal tank is installed around it – one to maintain a constant pressure and the other to prevent backflow. The pipeline network throughout the plant passes through a water seal of 200~400 mm before being fed to the flame for combustion.
It refers to the back pressure at the maximum emission level; this value also serves as the basis for setting the operating pressure of the safety valve. The flare manufacturer determines the Mach number at the flare outlet based on your emission volume and the properties of the emitted material, and then calculates the overall back pressure of the flare, including the pressure from the water seal
This back pressure cannot be achieved in the absence of emissions; when there are no emissions, the flare line is purged with an inert gas to maintain a slight positive pressure in the line.
Is this the pressure required by regulations for flare gas emissions? The actual pressure at the torch is not that high; it is merely a design constraint imposed to ensure a certain pressure drop in the piping
The actual torch doesn’t have such high pressure, right? We have installed dry gas holders on our low-pressure gas lines, with a design pressure of 3 KP. The water level in the water seal tanks is usually between 400 and 370. Since some waste gas always leaks into the gas lines, under normal conditions the gas flows into the gas holders; in emergency situations, it is directed directly to the flare for pressure relief. Normally, a pilot light is kept burning in the flare along with steam for protection – I’m not sure if this is a reasonable approach