Delayed Coking
Delayed Coking is a key thermal conversion process in many refineries today. It is a cyclic process that thermally cracks vacuum residue or other residue feedstocks into gas, light products and petroleum coke.
Despite being an established process for over 50 years, Delayed Coking presents several challenges. It is one of the most hostile environments in the refinery. Process temperatures can reach 1000 degrees F, and the by product coke is very abrasive and erosive. Fully solidified coke is harder than concrete. Due to these environmental factors, valves are cycled more frequently than in other parts of the refinery.
Valve failure can lead to the complete shut down of a refinery unit, and this down time is a large process and financial cost.
Valves for Delayed Coking
SchuF has designed a range of valves for use in Delayed Coking operations.These include the key switch, isolation, bypass, backpressure and overhead vapour valves. The valves are based on an original SchuF patented (received in 1914) invention – the Model 12 and Model 14 Lift Plug.
20 inch Lift Plug Isolation Valve, Photo: ©SchuF
SchuF can also provide valves for all other required functions in and around the delayed coking process from its extensive range of valves (e.g. for drain, warm or quench functionality the SchuF Model 30 valves can be used.)
Lift Plug Valve Advantages
The simple and rugged design delivers many benefits:
Protected Valve Seat (PVS) – Valve life is increased as seat or body faces do not come in contact with the flow media
Total sealing between body and plug ensures clean cavities and reduces maintenance significantly
Trunnion spindle guiding can be used for high pressure applications or to prevent vibration
Flushing and/or purging is only required during operation from open to close or vice versa. This leads to significant cost savings in comparison with other valve designs
Efficient Lift, Turn and Reseat (LTS) operator mechanism
Automated Control Panel (ACP) can be used to control single or multiple valves, actuators and sensors
Top or bottom entry design for ease of maintenance
