Difference Between Hydrocracking and Hydrotreating

The key difference between hydrocracking and hydrotreating is that hydrocracking includes the conversion of high boiling constituents into low boiling constituents, whereas hydrotreating includes the removal of oxygen and other heteroatoms.

Hydrocracking and hydrotreating are useful processes in petroleum oil refining. These two processes come under the category of hydroprocessing. Moreover, both of these processes take place in the presence of hydrogen gas. However, there is a distinct difference between hydrocracking and hydrotreating based on the principle and the mechanism.

CONTENTS

1. Overview and Key Difference
2. What is Hydrocracking 
3. What is Hydrotreating
4. Side by Side Comparison – Hydrocracking vs Hydrotreating in Tabular Form
5. Summary

What is Hydrocracking?

Hydrocracking is the process of converting high boiling constituents into low boiling constituents. That means; the reactants of hydrocracking reaction are constituents of petroleum oil having high boiling points, and the products are compounds having low boiling points. Further, this process is important because low boiling products are more valuable hydrocarbons, which include gasoline, kerosene, jet fuel, diesel, etc.

The process of hydrocracking is named as such because the breakdown of large molecules occurs in the presence of hydrogen gas. Usually, hydrocracking is done under severe conditions. It is because the reactants of hydrocracking feedstock are exposed to the reactor temperature for a long time.

What is Hydrotreating?

Hydrotreating is the process of removing unwanted compounds from petroleum products. It is important in producing high-quality fuel. Moreover, the components removed from petroleum oil includes oxygen, sulfur, nitrogen, metals, etc. These are impurities in petroleum fractions. It is very important to remove these contaminants because they cause detrimental effects on equipment, catalysts, quality of the final product, etc. Hydrotreating is done before hydrocracking to prevent the catalyst from contaminating.

What is the Difference Between Hydrocracking and Hydrotreating?

There are two types of hydroprocessing as hydrocracking and hydrotreating. The key difference between hydrocracking and hydrotreating is that hydrocracking includes the conversion of high boiling constituents to low boiling constituents, whereas hydrotreating includes the removal of oxygen and other heteroatoms.

When considering the importance of each process, hydrocracking is important to obtain more valuable products such as gasoline, diesel, jet fuel, etc. while hydrotreating is important to remove contaminants from a feedstock for hydrocracking.

The below infographic summarizes the difference between hydrocracking and hydrotreating.

Summary – Hydrocracking vs Hydrotreating

Basically, there are two types of hydroprocessing as hydrocracking and hydrotreating. The key difference between hydrocracking and hydrotreating is that hydrocracking includes the conversion of high boiling constituents to low boiling constituents, whereas hydrotreating includes the removal of oxygen and other heteroatoms.

Reference:

1. “Hydrotreating – an Overview .” ScienceDirect Topics, Available here.

Image Courtesy:

1. “Slovnaft – residual hydrocracking (RHC)” By Mikulova – Own work (CC BY-SA 3.0) via Commons Wikimedia