Where should the exhaust gas from the safety valve outlet, the breather valve outlet of the flammable liquid storage tank be connected? How does your factory handle it?

It’s usually connected to the gas flare line, right?~~~

Generally, it is connected to oil and gas recovery or exhaust gas treatment systems, and the gases are released into the atmosphere once they meet the specified standards (total non-methane hydrocarbons at 120 mg/m3). However, if the storage tank has an efficient sealing system, the outlet of its vent valve can be used to release gases directly into the atmosphere. The emergency relief valve is part of a nitrogen sealing system; in the event of a problem with the vent valve, gases can be released directly into the atmosphere

Sir, what does it mean to use an efficient seal for storage tanks? Why can this be discharged directly into the atmosphere in such cases? What do emergency relief valves and a nitrogen sealing system mean? Should an emergency relief valve be installed in the nitrogen sealing system? (Should the emergency relief valve here actually be an emergency relief manhole?) ) Looking forward to your advice

It would be better if you mentioned a flammable liquid, and then I can explain in detail. An efficient seal can generally be understood as a floating roof tank; you can refer to SH3007-2014, which contains detailed explanations on this topic. In large oil storage areas, there is a small condenser tank used to condense oil vapor into a liquid form; in emergency situations, pressure relief valves are needed, as specified in the relevant regulations. Take a look~

In the past, the safety valves, vent valves, and pressure relief manholes of Sinopec’s flammable liquid storage tanks were all connected to the atmosphere for discharge. In recent years, environmental protection laws have become increasingly strict, with tighter regulations on VOC emissions. According to GB 31571-2015, the standard for total non-methane hydrocarbons is set at 120 mg/m3, while Sinopec’s internal standards require a level of 50 mg/m3; even stricter limits apply to other specific pollutants such as benzene. 1) To meet emission requirements, the floating roof sealing structures of both internal and external floating roof storage tanks must now comply with the provisions of GB50341-2014 \"Code for Design of Vertical Cylindrical Welded Steel Oil Tanks\", GB31570, as well as Section 5.2 of GB31571 – Requirements for Pollution Control of Storage Tanks for Volatile Organic Liquids. In other words, efficient sealing methods such as liquid-filled or mechanical sealing should be used between the floating roof and the tank wall in both types of storage tanks ； Fixed-roof storage tanks should be equipped with a sealed exhaust system leading to organic waste gas recovery or treatment units. 2) In addition to meeting the requirements of SHT3007, intermediate raw material storage tanks of Class A B and Class B A, aromatic hydrocarbon storage tanks, light contaminated oil storage tanks, acidic water tanks, and those storage tanks whose exhaust gases contain high concentrations of oil vapor and sulfides and thus require gas emission collection and treatment shall be equipped with a nitrogen sealing system. In summary, the current practice is to use nitrogen blanketing and high-efficiency sealing for the storage tanks, with the outlet of their safety valves being directed to the flare system for disposal ； The outlet of the breather valve is routed through a flame arrester and a connecting pipe before being collected and sent to a specialized oil and gas recovery unit for treatment (such as condensation adsorption, catalytic combustion, etc.); the emissions from the pressure relief manhole are discharged directly into the atmosphere