Conversion · Refining
Hydrocracker
A high pressure unit that cracks heavy gas oil with hydrogen over a catalyst into diesel, jet fuel and naphtha.
What it does
Adding hydrogen while cracking gives clean, low sulfur middle distillates. It is flexible: it can shift output between diesel, jet and gasoline components.
Basics
| Feed | Heavy gas oils |
| Pressure | About 1,000 to 2,000 psi |
| Uses | Large amounts of hydrogen |
| Temperature control | Cool hydrogen quench between beds |
| Products | Diesel, jet fuel, naphtha |
Common failures
- Temperature runaway: the hydrogenation reactions release heat and keep accelerating if not controlled
Troubleshooting
- Symptom
- Bed temperatures rising quickly
- Likely cause
- Exothermic reactions outpacing the quench
- What to check
- Add quench hydrogen and depressure the reactors as the written procedure requires