Safe flow rate for flammable liquids, need it urgently online!
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Due to the low flash point of liquid toluene, which makes it prone to generating static electricity, its safe flow rate is controlled at 3 m/s. (In fact, the safe flow rate for toluene liquid is not specified in any standards; the safe flow rate for styrene is 2 m/s as a reference.) However, when toluene is distilled, whether under atmospheric pressure or under reduced pressure, the absolute pressure of the fluid does not exceed 0.1 MPa. So what should be the flow rate of the toluene vapor during the distillation process? If referring to the safe flow velocity of the gas: for example, the maximum flow velocity of hydrogen in carbon steel pipes is 8 m/s when the pressure is greater than 1.6 MPa, and 12 m/s when the pressure is between 0.1 and 1.6 MPa ； The maximum flow velocity of hydrogen in stainless steel pipes is 15 m/s. Toluene vapor isn’t as dangerous as hydrogen, right? Can we refer to the safe flow rate for hydrogen?
Can’t sink! ! ! ! ! ! Dear experts, professionals, and seniors, I hope you will kindly share your insights! I’m already anxious and irritable. Ha~~
There are only onlookers, no one helping~~{:3_69:}
Is this question too difficult for you to understand? Is it really too simple for you to be unwilling to answer? :L
In my opinion, there are no specific requirements regarding the flow rate of toluene vapor. Historically, certain safety-related flow rate limits have been established for hydrogen and oxygen, but in the case of hydrogen stations, the domestic regulations no longer apply. Toluene itself is also a hydrocarbon, so the flow rate restrictions should primarily be aimed at ensuring proper control of vibration and pressure drops; it should generally not exceed 18 m/s. When the pressure is low and pressure drop considerations permit it, the allowable flow rate can be increased slightly
Thank you! It was very rewarding. Also, may I ask where I learned that the regulations for hydrogen stations have been revoked? Could you please let me know?
In accordance with Articles 8.1.9 and 8.2.8 of the \"Code for Design of Oil Depots\" (GB50074-2014), when filling trains or road tankers with liquids of Class B, Class C, and Class A using a top-mounted loading arm, a loading arm that can reach the bottom of the tanker should be used. The flow velocity of the liquid inside the flexible hose should not exceed 1 m/s before the hose outlet is submerged in the liquid, and should not exceed 4.5 m/s after it is submerged. Toluene is a Class B liquid, and its flow rate can follow the requirements mentioned above.
Okay, it seems that for toluene liquid, the General Specifications for Category A B can be used. Anyway, I couldn’t find any documents specifying the safe flow rate for toluene. Thank you for sharing this information. What about toluene vapor? Could you give some advice? I think what Haiyou said on the 5th floor makes some sense. Do you agree?
I’m sorry; my words may have caused you to misunderstand. In fact, the standard referenced in GB50177 regarding hydrogen flow velocity is GB16912-1997. This standard from 1997 has been revoked, and it was updated in 2008, with more specific requirements for pressures ranging from 0.1 to 3 Mpa. Specifically, for pressures between 0.1 and 1 Mpa, the flow velocity is set at 20 m/s, while for pressures between 1 and 3 Mpa, it remains at 15 m/s. And GB50177 has not been updated further. In the AEMEB31.12 specification, however, a different interpretation is given to the limitation on hydrogen flow velocity. In short, excessive flow rates can lead to high pressure drops, noise, erosion, corrosion, an increase in the temperature of the fluid, and the generation of static electricity. The flow rate limits specified in previous domestic standards were primarily aimed at preventing static electricity issues; however, by strictly adhering to the current construction standards for metal pipes, such hazards can be avoided.
Well, okay. Thank you for your patient explanation
Since there are no clear standard data, the original poster referred to the flow rate of hydrogen; in their opinion, hydrogen is a more hazardous medium. As for toluene gas, considerations are mainly focused on operational requirements and process safety, for which anti-static measures such as grounding of high-voltage components and pipelines are employed. Please discuss; there are more authoritative explanations!