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8 Major Safety Devices ① Bypass Pipe (Valve): In automated chemical processing systems, bypass channels are installed on both the feed and discharge pipes. The main purposes of these bypass pipes are, first, to meet the requirements of centralized control operations, and second, to ensure compliance with safety standards to the greatest extent possible； Third, it meets the needs of continuous production of the device. The bypass pipe is usually installed above the automatic control valve; during operation of the device, it remains closed when the instrument-based automatic control valve is functioning properly. When the automatic control valve fails or is under maintenance, closing the maintenance valves on both sides and opening the bypass valve allows for continuous production. When a device failure leads to a loss of control, it is also possible to use bypass valves to redirect the flow and manage the situation, thereby reducing the risk. To determine whether the bypass valve is open or closed, one needs to check the length of the valve stem screw: if the screw is long, the valve is open; if it is short, the valve is closed. The valve is opened counterclockwise and closed clockwise. The shape speed must be determined based on factors such as pipe diameter and flow velocity; generally, the larger the pipe diameter and the higher the flow velocity, the slower the switching speed, in order to prevent sudden high pressures. To completely cut off the flow, both the main valve and the bypass valve must be closed simultaneously. ② The emergency shut-off valve is an important safety device in automated production systems. In the event of production abnormalities or accidents, the control room of the system can remotely shut off the feed valve directly. Emergency shut-off valves are generally installed on the feed pipes of devices that present a high risk, with maintenance valves on either side of them. ③ Safety valves, vent pipes, recovery pipes, and flares are important safety components in pressure systems; when the pressure inside a reactor or device exceeds a certain level, the safety valve opens automatically to release pressure or vent it. To ensure safety for the vented material, a recovery pipe is installed on the vent valve, allowing the vented material to be recovered and stored in the material tank, or to be vented to a flare for combustion. However, there are also some enterprises with relatively backward production technologies or poor production conditions that do not install recovery pipes and release the contents directly in case of an accident. The release of unrecycled material (sprayed material) can lead to combustion explosions or the escalation of accidents. Flame arresters should be installed on the pipelines for direct air defense. The operating pressure of the safety valve is adjusted according to the requirements of the device. ④ An explosion-proof membrane (rupture disc) is a thin metal sheet installed on the pressure relief port of a pressure device; it is also known as a rupture disc. When the pressure in the device exceeds a certain value, the metal sheet ruptures, thereby achieving the purpose of a pressure relief protection device. Since a large amount of material is ejected when the fireproof film bursts, it poses an even greater risk to the device. Therefore, a vent and recovery pipe is generally installed on the explosion-proof membrane to recover the material ejected after the explosion of the membrane into a tank or to vent it for combustion in a flare. However, some units with poor production conditions do not have vent recovery pipes installed. Some devices are equipped with double layers of explosion-proof membranes, and data acquisition devices are installed between these membranes to enhance the safety of the reaction. ⑤ To control process parameters, improve the quality and efficiency of chemical production, and ensure production safety, data collection devices are used. In general, such devices are installed in various parts of production equipment to collect data on temperature, pressure, materials (products), etc.; they provide operators and controllers with accurate information from the front line. The failure of these data collection devices can pose a serious threat to production safety. ⑥Most chemical processing units are equipped with nitrogen and steam purging systems. The piping networks of these systems are connected closely to the units, and when required by the production process, the nitrogen or steam systems can be activated automatically or manually to support the production process ； During equipment emergency repairs, the device can be purged and replaced to ensure safety during these repairs ； When the device fails or an accident occurs, it can be used to purge the pipelines, accelerate gasification, increase flow rates, and prevent material deposition and blockages. It can also dilute the material, reduce its concentration, slow down reactions, or provide pressure protection for the material. Additionally, it can serve as a diluent and fire extinguishing agent for dealing with leaks and fires. ⑦Alarms in the control room are triggered when there are abnormalities in process parameters such as the temperature, pressure, and flow rate of alarm devices and fire suppression systems. The detectors and alarms for combustible gas and toxic gas concentrations installed in the production facilities and their vicinity are all important safety devices in chemical manufacturing. To ensure rapid and effective response in the event of an accident at a facility, many chemical processing plants are equipped with water spray systems, foam spray systems, high-pressure fire hydrant systems, as well as fixed fire cannon cooling and extinguishing systems. These fire suppression facilities play a crucial role in controlling the development of the situation under certain conditions. ⑧Pipeline identification: Chemical production pipelines are crisscrossing and highly complex. To facilitate management, standard identification systems for these pipelines have been established in the industry; this not only helps production workers carry out their tasks more easily but also aids in firefighting and rescue operations. Normally, pipelines for materials that are prone to corrosion are made of stainless steel and are not painted ； The circulating water pipeline is painted ink green ； Powder coating on acid (alkali) liquid pipelines by color ； The nitrogen purge pipeline is painted light yellow ； The vent pipeline (emergency discharge pipeline) is painted yellow ； Fire water supply and extinguishing agent delivery pipelines are painted red ； The steam pipeline is fitted with insulation covered by galvanized iron sheeting ； The main material pipeline is not painted.