Abhilash Pavanthalakal

The objective of the FCC PC unit is to produce propylene by catalytically cracking unconverted oil from VGO Hydrotreater. The unsaturated Gas plant separates and recovers the light hydrocarbon vapours and hydrocarbon liquid streams produced by the cracking reactions in the FCC reactors.The FCC complex will be designed to process 2, 220, 000 TPA of unconverted oil from the VGO HDT unit. The unit capacity and severity are determined by the light olefins productions.
Stream Factor: 8000 hours per calendar year
Run Length : Minimum 3 years between turnarounds
Turndown : 50% turndown of 110% capacity while meeting all product specifications.

1.1 Design Case:
Feedstock : Mix of straight run VGO and HCGO from CDU/VDU and DCU (processed 90 wt% Arab Heavy + 10 wt% Doba Crude)
Capacity : 2, 220, 000 TPA with 10% overdesign
Processing Objective : Max propylene ex PRU is 433, 000 TPA with 10% overdesign (Based on 96.5 wt% recovery)
1.1.1 Check Case:
Feedstock : Mix of straight run VGO and HCGO from CDU/VDU and DCU (processed 90 wt% Arab Heavy + 10 wt% Doba Crude)
Capacity : Preferably processing capacity 75% or above.
Processing Objective (1): Minimum propylene (preferably 0 flow) or maximum propylene 50, 000 TPA, meeting LPG specification.
Ob

After ascertaining the quality and quantity of the oil received, it is then pumped into the Waste Oil or Used Oil storage tanks. From these tanks the oil is pumped into the process unit. The Process Plant consist of four distillation columns, first three of them operating in series. Each distillation column, consisting of reboilers/heaters, coolers and condensers in addition to vacuum system, circulating pumps etc., is called module. The unit is capable of re-refining of Used Oil and for Recycling of Waste Oil. The process conditions are to be adjusted depending on whether the feed is Used Oil or Waste Oil and also depending on the type of Wast Oil.

The main objective of FCCU revamp is maximising production of valuable products like LPG, diesel components, gasoline improve gasoline octane, improve run length etc and to meet Bharath stage II (Euro -II) MS/Diesel specifications. The unit was designed be M/s UOP to be Side-By-Side (SBS) type with showerhead nozzles and Tee disengager. The unit was revamped based on the basic design of UOP to increase the Capacity of 1.5 MMTPA of VGO feed without HCO recycle. The latest revamp envisages the increase in capacity from 1.4 MMTPA to 1.75 MMTPA.

Working section:
FLUIDISED CATALYTIC CRACKING UNIT
• Converter Section.
• Catalyst Regeneration Section.
• Main Fractionation and Gas Plant Section.
• Wet Gas Compressor.