Oil Processing: Delayed Coking

Thru-Plus® Delayed Coking

BHTS acquired ThruPlus® Delayed Coking technology from ConocoPhillips in 2011.  Building on a longstanding engineering & technology relationship between Bechtel and ConocoPhillips (and predecessor Conoco), BHTS continues to offer competitive advantages in design, safety, maintenance and operational excellence. 

The proven ThruPlus® Delayed Coking technology is the cleanest, most cost efficient process for converting low value petroleum residues and non-conventional heavy oils into high value transportation fuels and byproduct fuel-grade or anode-grade solid coke. Developed and proven through Conoco R & D, implemented in owner / licensee / joint venture refineries and improved by experience gained from Bechtel EPC projects, BHTS remains the industry choice for top tier delayed coking technology.

The process

Delayed coking is a semi-batch cyclic process that thermally cracks a variety of residual oil feeds into light gases, naphtha, diesel, heavy gas oil and petroleum coke.  The heart of delayed coking technology is the furnace, in which a mixture of oil and steam is superheated in a short residence time environment such that coking in the furnace tubes is avoided.  Superheated furnace effluent flows directly into an empty coke drum (one of a matched pair of drums) where a combination of lengthy residence time (typically in the 18-hour range) and high temperature sustain the cracking reactions which build up a bed of solid coke while the cracked hydrocarbon vapor products flow to a fractionation system for cooling, separation and recovery of liquid products.  Light gases and liquids are routed to the coker gas recovery section for separation of fuel gas, LPGs and naphtha products.

While the coke drum is filling, its parallel (sister) drum is undergoing steam stripping, cooling, water draining, top and bottom head removal, high pressure water jet coke cutting, re-heading, air-freeing and pre-heating in preparation for return to service as the receptacle for the continuous flow of the superheated furnace effluent stream.  These cycles are repeated until the entire coker plant must be shut down for required maintenance, inspection and equipment cleaning.

BHTS ThruPlus® Delayed Coking Process

What makes us different?

  • Experienced staff, including former ConocoPhillips experts now with BHTS
  • Advances in safety, reliability, dust control, furnace specification, coke drum specification, coke drum interlocks, water management, vent gas recovery
  • Furnace design based on operating feedback and advanced simulation of radiant section tube coking tendencies; specification suitable for competitive bidding
  • Robust coke drum design specification; bulge & crack resistant; designed for 7,000 fatigue stress cycles
  • Innovative multi-point feed nozzle design for coke drums with automated bottom unheading valves to avoid hotspots and blowouts
  • Patented Distillate Recycle technology for selective liquid yield shifting and extending furnace run length
  • Availability of Bechtel expertise for solids handling, mechanical, civil, piping design, metallurgy, control systems, constructability, cost estimating, advanced simulation
  • Experienced with 15 Delayed Coker EPC around the world
  • Active network of licensees (onsite support, studies, technology symposia)

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