What are the special valves in a catalytic cracking unit?

Special valves of the unit include the flue gas inlet butterfly valve, high-temperature gate valve, and regeneration slide valve

Special valves for catalytic cracking units – single and double-acting slide valves, plug valves, high-temperature butterfly valves, high-temperature gate valves. The single-acting slide valve is a slide valve with a sliding plate that is used in the catalyst circulation pipeline between the two reactors in a catalytic cracking unit. Used to adjust the catalyst circulation rate during normal operation. Used to quickly cut off the catalyst circulation and the connection between the two vessels in case of startup/shutdown or an accident. Double-acting slide valve valve specifically designed for catalyst cracking. A slide valve with two valve plates, capable of opening and closing in both directions simultaneously. Installed on the flue gas outlet pipeline at the top of the fluidized catalytic cracking regenerator to control the pressure of the regenerator, keeping it roughly in balance with the reactor pressure. The operating temperature ranges from 700 to 780°C, with a control sensitivity of 1/400 and an accuracy of 1/100. The plug valve is one of the key equipment in catalytic cracking units. Based on their role in the fluid catalytic cracking (FCC) process, they can be divided into feed catalyst plug valves and regenerated catalyst plug valves. These valves are installed on the feed and regeneration risers at the bottom of the regenerator, and they are used to regulate the flow rate of feed and regenerated catalysts, thereby controlling the level in the stripping section and the temperature at the outlet of the lift pipe. Additionally, they serve as shut-off valves to stop the circulation of catalysts when the plant is started up or shut down. The high-temperature butterfly valve is installed on the pipeline between the flue gas turbine and the high-temperature gate valve, serving as a control valve to regulate the pressure in the regenerator and the flow rate of flue gas entering the turbine; the medium is the high-temperature flue gas containing catalyst generated by the regenerator. The high-temperature gate valve is vertically installed on the horizontal flue gas pipeline in front of the high-temperature butterfly valve. When the flue gas turbine is operating normally, this valve remains fully open; however, during shutdowns or in case of an accident, it is closed promptly via the actuator to cut off the flue gas, thereby ensuring the safety of the turbine as well as meeting the requirements for shutdown and maintenance. This post was last edited by Li Xuegang on 2009-2-12 10:25.]

There is also a one-way damping valve at the main fan outlet.

The catalytic special valves include regenerative and standby single-acting slide valves and plug valves, flue double-acting slide valves or butterfly valves, flue gas turbine inlet butterfly valves and flat gate valves, main air single-damping valves, large and small flare butterfly valves, etc.

Double-acting slide valve on the flue gas pipeline； The raw material plug valve and regeneration plug valve (regeneration slide valve) on the two units ； Damping check valve on the main air pipeline ； Butterfly valve for oil and gas on the overhead oil and gas pipeline of the fractionation tower.

1. The double-acting slide valve is installed on the flue gas pipeline at the outlet of the regenerator. Control the regenerator pressure. 2. Regeneration and standby slide valves (plug valves) are installed on the regeneration and standby risers. Control the reaction temperature and the inventory in the stripper section separately. 3. High-temperature butterfly valve at the flue extractor inlet is installed on the flue gas pipeline at the inlet of the flue extractor. Adjust the air intake of the flue gas machine, and together with the double-acting slide valve, control the regenerator pressure. 4. High-temperature gate valve at the flue extractor inlet is installed on the pipeline at the flue extractor inlet. It serves as a flue gas shut-off valve in front of the high-temperature butterfly valve at the inlet of the flue gas extractor. 5. The rich gas flare butterfly valve and pneumatic gate valve are installed on the inlet pipeline and the outlet pipeline. 6. The one-way damping valve at the main fan outlet is installed on the pipeline at the exit of the main fan. Used for the low-flow self-protection of the main fan to prevent catalyst backflow. There are also the flue gas extractor bypass butterfly valve, the flue high-temperature butterfly valve, etc.

As a supplementary note, the feed and emergency bypass safety valves are installed in the feed valve assembly； Pneumatic gate valves at the inlet and outlet of the compressor, as well as the rich gas pipelines at these same locations, ensure a fast switching speed while preventing any ignition of the leaked rich gas ； Corner valves for slurry systems, suitable for applications with high viscosity and high solid suspensions. Flue gas bypass butterfly valve for waste heat boiler.