Hydrocracking operating window Hydrocracking is carried out under what general combination of pressure and temperature compared with other refinery conversion processes?

Introduction / Context:
Hydrocracking upgrades heavy feeds (e.g., vacuum gas oil) into middle distillates and naphtha using hydrogen and bifunctional catalysts. Recognizing its typical pressure–temperature regime helps differentiate it from catalytic cracking, reforming, and hydrotreating.

Given Data / Assumptions:

• Bifunctional catalysts (acid + metal) are used.
• Hydrogen partial pressure is substantial to suppress coke and saturate olefins/aromatics.
• We compare qualitative ranges only.

Concept / Approach:
Hydrocracking requires high temperature to crack heavy molecules and high hydrogen partial pressure to maintain catalyst life, control coke, and saturate intermediates. Operating pressures are typically several tens to over a hundred bar, and temperatures are in the several hundred Celsius range—thus “high–high” compared with many other units.

Step-by-Step Solution:

Verification / Alternative check:
Standard process summaries list hydrocracking with the highest pressures among mainline refinery conversion units.

Why Other Options Are Wrong:

• Low–low / High–low / Low–high: Do not match the simultaneous needs for cracking kinetics and hydrogen effects.

Common Pitfalls:
Confusing hydrotreating (also high pressure but generally lower severity) with hydrocracking; hydrocracking is more severe in both temperature and conversion level.

Final Answer:
High pressure and high temperature