Can any kind of exhaust gas from chemical processing units be sent to the flare system?

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Principles for the installation of flare systems
I. Relevant standards and regulations: “Fire Protection Design Code for Petrochemical Enterprises (2018 edition)” GB50160-2008, “Design Code for Flammable Gas Emission Systems in Petrochemical Industries” SH 3009-2013, “Installation of Flare Systems” HG/T 20570.12-1995
II. Standard requirements:
(1) Article 5.5.4 of the “Fire Protection Design Code for Petrochemical Enterprises (2018 edition)” GB50160-2008 stipulates that the outlets of safety valves on equipment handling flammable gases and liquids must comply with the following requirements: 2. The discharge pipes connected to the safety valves of equipment handling flammable gases should be connected to the flare system or other safety discharge facilities； 3. Combustible gases or liquids that may ignite immediately after release should be cooled before being connected to the venting facilities ； 4. Combustible gases that may contain liquid droplets should be routed to the flare system after passing through a liquid separation tank. Article 5.5.7 requires that Class A, B, and C equipment shall be equipped with emergency discharge facilities for accidents, and shall comply with the following provisions: 1. For equipment handling liquefied hydrocarbons or flammable liquids, it must be possible to discharge such hydrocarbons or liquids from the equipment to a safe location, with any remaining amount being discharged into a flare ； 2. For combustible gas equipment, it should be possible to vent the combustible gas inside the equipment into a flare or a safe venting system. Article 5.5.15 requires that liquids, combustible gases with low calorific value, combustible gases containing oxygen or halogen elements and their compounds, combustible gases with extremely high or high toxicity, inert gases, acidic gases, and other corrosive gases shall not be discharged into the plant-wide flare system; instead, separate emission systems or systems for treating such emissions must be installed. (Explanation of the provisions of this article: Discharging combustible gases with a low calorific value into the flare system can disrupt the stable combustion of the flare or cause it to go out) ； The release of oxygen-containing flammable gases into the flare system can result in the formation of explosive gases within that system and its facilities, which may lead to backfire and explosions, as well as damage to pipes or equipment ； Acidic gases and other corrosive gases can cause air pollution as well as corrosion of pipelines and equipment; therefore, a separate acidic gas flare should be installed. For gases with extreme or high toxicity or those containing corrosive substances, having separate treatment and emission systems in place helps ensure safe production. The toxicity classification should be determined in accordance with the current standards, namely **“Classification of Hazards from Occupational Exposure to Toxic Substances” GB 5044 and the “List of Highly Toxic Substances” (Document No. Wei Fa Jian Fa 142)**. However, benzene and carbon monoxide emitted by petrochemical enterprises lose their toxicity after being fully burned in a flare system; therefore, such substances or flammable gases containing them can still be discharged into a public flare system. )( 2) Article 4.3 of the \"Design Code for Flammable Gas Emission Systems in Petrochemical Industries\" SH 3009-2013 requires that no various liquids shall be discharged into the plant’s flammable gas emission system. Article 4.4 requires that combustible gas containing asphalt, residue oil, powder, or solid particles be separated and treated within the facility before being released. Article 4.5 requires that combustible gas streams containing hydrocarbons of C5 or higher grade, or water vapor, be passed through a liquid separation tank prior to discharge, in order to remove liquid droplets with a size of 600 um or larger. Section 5.1.4 requires that an acidic gas emission system be installed separately. Article 5.2 stipulates that gases which can be discharged into the plant-wide combustible gas discharge system: Gases from the following various sources in 5.2.1 may be discharged into the plant-wide combustible gas discharge system: a) Combustible gases that cannot be utilized by the production facilities and must therefore be discharged ； b) Flammable gases released due to accident venting or safety valve operation ； c) Flammable gases emitted during startup, shutdown, and maintenance operations ； d) Flammable gases discharged intermittently over short periods of time, such as those from liquefied petroleum gas pumps ； e) Toxic, harmful, and flammable gases emitted from production equipment, containers, etc. 5.2.2 Gases with a calorific value lower than 7880 kJ/Nm3 shall have their calorific value adjusted before being discharged into the plant’s flammable gas emission system.