Fluid Catalytic Cracking (FCC)

Fluid Catalytic Cracking (FCC) – Application Overview

An FCC is used to convert low value gas oils to valuable products like naphtha and diesel and slurry oil. It increases the hydrocarbon ratio by carbon rejection in a continuous process. In this process, a hot “fluid” catalyst at 538°C cracks heavy gas oil feed into gas/LPG, FCC petrol, light cycle oil, slurry oil and coke. The process converts straight-run atmospheric gas oils, vacuum gas oils, certain atmospheric residues and heavy stocks recovered from other refinery operations into high-octane petrol, light fuel oils and olefin-rich light gases such as propylene.

The FCC unit is comprised of three major parts (reaction, regenerator and combustion sections) and is considered the “heart” of the modern refinery. Major fuels conversions (gasoline) are produced out of the FCC. These units are straight run typically 36 or 48 months with fluidized bed catalytic reaction with AVGO or hydrocracker routed feed stock for low sulfur diesel and high octane gasoline production,light fuel oils and olefin rich light gases such as propylene with FCC a hot ‘fluid’ catalyst at 1000°F (538°C) cracks heavy gas oil feed. (Note: if feedstock not from the hydrocrackers then the end products are hydrotreated to meet ultra low sulfur specifications.)

PRIMARY PROCESS TECHNIQUE: Catalystic cracking increases H/C ratio by carbon rejection in a continuous process


  • Gas oil feed is dispersed into the bottom of a riser using steam
  • Thermal cracking occurs on the surface if the catalyst
  • Disengaging drum separates spent catalyst from products vapors
  • Steam strips residue hydrocarbons from spent catalyst
  • Air burns away the carbon film from the catalyst in either a partial burn or full burn mode operation.
  • Regenerated catalyst enters bottom of riser – reactor


  • High octane gasoline, propylene, butylene, LPG, kerosene, jet fuel, naphtha, slurry oil
  • Lighter olefins and aromatics
  • Low coke production as burned in regenerator with heat for cracking reactions
  • Slurry – later routed to hydrocracker or blended into coker feed
  • CO2 produced helps in steam for utilities


  • Feed pump isolation valves
  • Frac bottoms pump isolation valves
  • Frac recirculation
  • Compressor suction 1st and 2nd stage isolation valves
  • Catalyst handling valves (spent catalyst withdrawal, catalyst sampling, catalyst addition, catalyst fines block valves)
  • TSS FSS separator isolation valves
  • Pump around valves
  • Slurry loop valves


  • High-temperature, thermal shock (760 -1400°F)
  • Low pressure (30~60 PSI)
  • High erosion in catalyst lines, maintain zero-leakage with positive isolation from each section as the catalyst are very expensive and a reliable zero-leakage valve helps in minimizing catalyst replacement
  • Acidic corrosion
  • Reliable longer operational valves for dependable isolation
  • Zero-leakage in all operating conditions as well as low fugitive emission
  • Fire safe and certified

BENEFITS OF A VALVTECHNOLOGIES’ PRODUCT: Integral seat design, zero-leakage at all operating conditions, purging to extend life of the equipment and also plant available. Fire safe and certified, in-house RiTech® coating technology.

TOTAL COST-OF-OWNERSHIP: Five years and above operation, customer can upgrade trims and coating and document it for the next run saving up a lot time and money.

Integral seat

  • It is inherently impossible for the seat to disassociate from the valve body under any operating condition
Highest spring strength in the category

  • Spring strength inhibits ball movement
  • Maintains positive seating under various pressure differentials and Is a necessity for zero leakage and longevity
  • The spring strength is made evident by the two-piece body configuration; the body must be mechanically torqued to close due to the compression strength of the spring. It is not feasible to have high spring strength with top loaded or end loaded valve internals.
Coatings/seating surface

  • RiTech® coating is applied precisely and has high bond strength
  • ValvTechnologies is the only known ball valve manufacturer to bring their coating process in house and under robotic control.



Item Applications Temp range (°F) Pressure (psi) Size (in)
1 Feed drum emergency block valve 200 – 300 50 6 – 12
2 Feed isolation 200 – 300 100 6 – 10
3 Spent catalyst withdrawal root isolation 800 – 1425 30 2 – 8
4 Spent catalyst withdrawal block valve 800 – 1425 30 2 – 8
5 Throttling spent catalyst withdrawal valve 800 – 1425 30 2 – 8
6 Catalyst regenerator inlet 800 – 1425 30 2 – 8
7 Catalyst regenerator outlet 800 – 1425 30 2 – 8
8 Frac bottoms emergency block valve 500 – 850 30 8 – 20
9 Frac tower bottoms filter isolation 500 – 850 150 6 – 12
10 Frac bottoms exchange isolation 500 – 850 150 4 – 10
11 CO boiler inlet isolation 500 – 850 150 4 – 10
12 CO boiler outlet isolation 500 – 850 150 4 – 10
13 Wet gas compressor surge control valve 100 – 200 30 – 200 10 – 20
Item Applications Temp range (°F) Pressure (psi) Size (in)
 1 Third stage separator isolation 800 – 1425 30 4 – 10
2 Fourth stage separator isolation 500 – 1000 30 6 – 12
3 Spent catalyst storage hopper isolation 200 – 500 ATM 4 – 10