High-Temperature & High-Pressure Lifting Type Metal-Seal Plug Valve for Delayed Coking Unit

The high-temperature & high-pressure lifting type hard-seal plug valve is the preferred shut-off valve for the delayed coking unit under conditions of high temperature, high pressure, easy coking, and presence of coke powder. It perfectly fits key parts such as heating furnaces, coke towers, and large gas pipelines, addressing the problems of traditional gate valves and plug valves, such as easy clogging, leakage, and short lifespan.

Extreme operating conditions of the delayed coking unit (the core basis for valve selection)
(1) Temperature: Outlet of heating furnace / Top of coke tower 495–505℃, with local temperature reaching 550℃
(2) Pressure: Class 300–900 (PN50–PN160), pressure fluctuates significantly during coke tower switching
(3) Medium: High-temperature residual oil, gas, steam, containing a large amount of coke powder and asphaltene, prone to coking, adhesion, and erosion
(4) Operation: Frequent switching (12–18 hours / cycle), rapid opening and closing, bidirectional sealing, anti-leakage
(5) Risk: Coking blockage, sealing surface erosion, thermal expansion and contraction jamming, hydrogen sulfide leakage

Why Choose "Elevated-Type Hard Sealing Plug Valve" (Core Adaptability)
(1) First, lift, then rotate, and finally compress: The sealing surface is friction-free throughout the opening and closing process, completely avoiding damage to the sealing surface caused by coke powder.
(2) Metal hard seal (hard alloy / tungsten carbide): Resistant to high temperatures, erosion, and coking, with a much longer service life than soft seals.
(3) Equal-diameter full-flow channel: Extremely low flow resistance, less prone to coking, suitable for high-viscosity and particle-containing media.
(4) Self-cleaning + blow-off design: The valve chamber can be purged with steam or nitrogen to prevent coke powder from accumulating and getting stuck.

Typical Application Locations in the Delay Coking Unit
(1) Heating Furnace System (Most Harsh Operating Conditions)
Heating furnace outlet isolation valve: DN200–DN600, Class 600–900, 495–505℃, containing coal powder and oil gas.

Furnace tube feed valve / circulation valve: Frequent opening and closing, requiring quick, reliable, and anti-coking performance.

Selection criteria: Integral forged valve body (WC9/F91), hard alloy overlay sealing surface, with blow-off holes, electric / pneumatic actuators.

(2) Coke Tower System (Core Switching Location)
Coke tower feed isolation valve (four-way / three-way switching valve): Alternating between one furnace and two towers, once every 12–18 hours, high-temperature residue oil + coal powder.

Large gas line isolation valve: From the top of the tower to the fractionating tower, high-temperature gas and oil, bidirectional sealing.

Coking removal system valves: High-pressure water, steam, wear-resistant, impact-resistant
Selection criteria: DBB double-blocking discharge, fireproof certification API 607, anti-sulfur NACE MR0175

(3) Fractionation and Gas System
Bottom circulation valve of the fractionation tower: High-temperature oil slurry, containing coal powder, anti-coking.

High-temperature steam / gas isolation valve: Resistant to high temperature, anti-leakage
Selection criteria: Zero-leakage packing structure (zero leakage), grease injection sealing system (emergency sealing)

In the delayed coker, the high temperature and high-pressure lift plug valve is become the standard valve part for the whole strict system. The Metal to metal plug valve has features of frictionless opening and closing, metal hard sealing, anti-coking property and long service life. It is widely used in the outlet of the heating furnace, the switching of the coke tower, and large oil and gas pipelines.