Overpressure in the torch pipeline network

Won’t the excess pressure in the container be reduced through the safety valve and into the exhaust main? If overpressure occurs due to blockages or issues with the flare system, a safety valve can be installed on the main pipe leading to the flare to release the pressure

Typically, refineries have two pipelines leading to the flare. One is the acidic gas line, and the other is the low-voltage line. Acidic gas streams are corrosive (although they are waste gases), and cannot be directly released into flare systems such as low-pressure gas networks; they need to be routed separately all the way to the top of the flare. Other non-corrosive combustible gases from the device can be directly discharged into the low-voltage pipeline within the device. The low-pressure gas lines in large refineries can be several kilometers long. For low-wattage emissions, at most 3 to 4 devices emitting simultaneously are considered (usually 2 to 3), and the total pipe diameter and the pressure drop near the devices are calculated based on the most hazardous emission levels. The main pipe is thick enough, so the flare system pipeline generally never experiences overpressure. The water seal tanks under the flare have a water seal of 200–400 mm (depending on the medium); if this value is exceeded, the flare is activated. Note: 1. The torch line should be laid with a gradual increase in elevation, that is, in a stepped layout. So that when condensate forms, it can flow back by gravity to the separation tank at the side of the device. The pump is returned to the device. 2. The flare line must not have any depressions; in other words, there should be no U-shaped low points, as this could lead to liquid accumulation, increased back pressure, and obstruction of emergency discharge – dangerous! 3. Stress calculation is generally required for the torch line. Two industrial processes: one is the condition of using steam for line cleaning ； The other is the condition with heavy water filling when checking airtightness.

If your plant is not a proper petrochemical plant – it does not have dual power supply, meaning that in the event of a power outage, all production units in the plant will have to use flares – then you must calculate everything based on the scenario of simultaneous flare use, especially regarding the main pipe diameter and the flare tip.

The basic principle of torch pipeline design is: separation by quality and pressure. In other words, flare gas with different gas components, as well as flare gas at different pressure levels, are routed through separate flare gas pipelines.

The calculation of flare gas emissions can be carried out in accordance with SH3009; it cannot be simply added up.

What was said upstairs is comprehensive. I hope the original poster will consult more with the expert on floor 8 – Zhi Zhe Ming. He has a fairly thorough understanding of the specifications for SH3009. I’m an outsider. We sincerely hope that Zhi Zhe Ming, the senior technical advisor from Haichuan, will use his far-sighted perspective to explain to us all the relevant precautions and key design points. We’re all ears! Thank you, Hai Chuan Senior Technical Advisor!

The specific situation needs to be analyzed on a case-by-case basis; first, it is necessary to examine the flare gas emission system diagram of your factory in order to determine certain operating conditions.