Valves for Delayed Coking
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The SchuF Valve Range for Delayed Coker Systems

SchuF is a highly specialised group of companies, whose expertise is the design and manufacture of process control valves for critical service applications. Patented Innovation Rugged Simplicity SchuF is the inventor of the Lift Plug Valve. The patent dates back to 1914. Since its invention SchuF has continued to develop the valve, with many innovations. These include the addition of electric, hydraulic and pneumatic operators, and new applications such as switching and dumping variants. It also pioneered the inverted plug design, which can be serviced in line; designed flushing systems;...

The Original Lift Plug Valve The original invention features an upside down plug with a removable lid at the bottom. The inverted plug consists of curved plates cast as a single plug and connections to allow cleaning and declogging of the spaces in, above and below the plug whilst the valve is in service. The “original” Lift Plug Valve – 14NR This first valve already satisfied all requirements for an effective double block & bleed. The 2 Way Type 12NR This two way valve features standard lengths to API and DIN. The bore section is oval, but the cross-sectional area matches that of a full...

Actuation Procedure SchuF Valves can be actuated electrically, pneumatically or hydraulically. The SchuF LTS lift/turn/ (re)seat operation allows a single rotational actuator to lift, turn and reseat the plug. Two actuators can also be used; one to lift and lower, and one to turn. Special plug plating or the use of dissimilar metals can be applied to allow turning of the plug without lifting or reseating it. Automated Control Panel SchuF delivers an Automated Control Panel (ACP) consisting of programmable logic controllers and peripheral instrumentation. The control panel actuates the...

Delayed Coking Systems Overview Delayed Coking is one of the most hostile environments in the refinery with process temperatures of 1000° F and which outputs a very abrasive and erosive coke by-product. As a result valves are cycled more frequently than in other parts of the refinery and failure can lead to complete shut down of a unit. This can lead to large process and financial cost. Delayed coking is a semi-continuous thermal cracking process. After being heated in a coke furnace the coke feed (a liquid-vapour combination) is fed into and separated in a coke drum. Delayed cokers are...

SchuF Valve Portfolio for Delayed Coking SchuF SwitchPlug Valves The Switching Valve is the heart of the delayed coker process. The SchuF SwitchPlug Valves illustrated on this page are ideally suited as switching valves in delayed coker systems. A four way switching valve is typically required to allow coke feed into whichever coke drum is active. During start up, shut down or an emergency the valve can also bypass both drums. If three drums are used, SchuF can supply a single valve with four outlets. SchuF switching valves offer great flexibility: ▪ the plug can be straight up or inverted...

IsoPlug Valve for Isolation and Bypass ControlPlug for Backpressure Control – Type 12NO The IsoPlug valve can be supplied in sizes up to 36”. Smaller sizes up to 16” are usually actuated electrically with the SchuF LTS operator. Valve sizes over 24” are usually fitted with two actuators, controlled by a PLC housed in the control panel supplied with the system The ControlPlug for Backpressure is specially gold plated or manufactured in dissimilar metals so it does not need to be lifted before turning. It is never fully closed so the associated drop in sealing level to class III is not...

Advantages of the Lift Plug Valve for Delayed Coking The key advantages of a lift plug valve for coking systems are their simplicity and crevice free design. In any position, be it open, or in a particular switching position, the plug and the body form a smooth continuous contour, without gaps or crevices. This eliminates the need for flushing during routine operation. To operate the lift plug valve, the plug is raised slightly from the body. It can then be turned easily, without the type of torque associated with a ball valve. Once the plug has been turned to its required position, the...

Lift Plug and Ball Valve Comparison Table Lift Plug Valve Ball Valve Simple rugged design, only two main parts Complex design, many major parts Plug seizing is not possible Seals do not wear during operation Seal wear with every operation Seat seals are load free during rotation, but thrust loaded by lowering the plug after the rotation, ensuring a perfect seal Seals are exposed to the process while loaded, sealing cannot be improved by the actuator Flushing only required during valve operation High ushing requirements, leads to high cost of ownership If ushing fails while valve is in...

Coal Liquefaction Case Study The valves included a number of special attributes such as the SchuF proprietary impulse control system, optimised flow characteristics, solid Tungsten Carbide trim and body sleeve, removable critical parts in-situ, SchuF cross sectional acceleration design, proprietary packing protection and an integral quenching system. A major Chinese coal company established a Direct Coal Liquefaction Plant in Inner Mongolia. Direct Coal Liquefaction presents a number of challenges for valve systems: These critical valves were delivered on time to perform in one of the most...

General Specifications Coker Valve Portfolio: ▪ ▪ ▪ ▪ SwitchPlug IsoPlug ControlPlug QuenchPlug Valve sizes: ▪ SwitchPlug – Typical sizes range from 8“ to 24“. ▪ IsoPlug – Typical sizes range from 8“ to 36“. Materials and Options: ▪ Body WCB, WC6, WC12, WC12A Rating: Class 150 to 900 ASME, DIN or JIS. Flow Direction: Bi-directional; flow to open or close Coking Defense System: ▪ 1. Steam flushing during plug operation ▪ 2. Integral flush drain/dump valve enabling steam purging above or below the plug ▪ 3. IsoPlug valves with detachable bottom lids to allow hydro blasting of any lodged coke...