Delayed Coker

Delayed coking process is a highly endothermic thermal conversion that transforms the heaviest crude oil fractions into high valuable products. The process derives its name from the fact that unit conditions are controlled so that coke formation does not occur in the furnace, but rather in downstream vessels (coker drums) specifically designed to provide the time for these reactions to go to completion and the resulting coke to accumulate.

1.Coker Fired Heater: he putrpose is to heat the feed to the temperature necessary to initiate the coking reactions as rapidly as possible – 500°C with multiple cells & 2 pass per cell using refinery fuel gas and steam air decoking and pigging connection with air preheat system. The feed flow rate to each pass is individually controlled and high pressure steam is injected into each of the furnace coils to help maintain the desired velocity / residence time to suppress the formation of coke in the tubes.

2.Coker Chambers (drums) with ID = 9 m & H = 29 m, operates at lower pressure and high T / 2.5 barg – 450°C at outlet, the fired heater effluent flows into the bottom of an initially empty Coker Drum, while its paired drum is offline for coke removal & preparation for return to coking service. Inside the online Coker Drum, a combination of residence time, T and pressure converts the feed to cracked hydrocarbon vapors and coke. Cyclic service with next steps: Coke Drum Steamout Step, Coke Drum Quench Step, Coke Drum Drain and Cutting Steps and Coke Drum Backwarming Step

3.Main Fractionator with 26 real trays and 1.8 barg / 120°C on top vs 2.5 barg / 300°C in bottom, separate the coker drum mixture in gas, coker naphtha, light coker gasoil, heavy coker gasoil. The column has 2 side strippers LVGO & HVGO using MP steam to remove the lights and pumparrounds for heat integration and to reduce ID of main column

4.Wet Gas Compressor 2 stage centrifugal type with suction p 1.2 barg / 55°C, first stage discharge p = 4.5 barg / 110°C and second stage 14.0 barg / 125°C fit with electrical motor and MW variation of +/- 2-3 % embedded in design

5.Absorber / Stripper main function to recover LPG from the off gas going to fuel gas with 38 real stages / 40% efficiency for Absorber and Stripper with 40 reals trays & 50 % efficiency. Absorber top 13.0 barg / 65°C and Stripper top 13.7 barg / 62°C

6.Sponge Oil Absorver with 25 real trays / 40 % efficiency, the vapor contacts a lean sponge oil stream of LCGO to recover pentane and heavier material - the vapor leaves the top of the Absorber/Stripper and is routed to the bottom of the Lean Sponge Oil Absorber. Operating conditions at top 12.6 barg / 65°C & bottom 12.8 barg / 77°C

7.Sour Gas Absorber remove H2S from gas and use 20 real trays 11.6 barg / 45°C on top vs 11.2 barg / 62°C in bottom with MDEA as solvent 0.01 lean load / 0.4 max rich load

8.Blow down system closed type with main goal to condense / collect steam & hydrocarbon vapors generated during the steam stripping step, the water quenching step and the backwarming step of the coke drum decoking cycle. Also condense and collect the steam and heavy hydrocarbon vapors generated during coker startup and shutdown as well as during coke drum overpressure different upsets: quench column, ovhd condenser, settle vessel, blowdown water pumps, heavy slop oil pumps and sludge package. Quench column 0.3 barg / 175°C on top and in bottom 0.4 barg / 185°C.

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