Dec-2022

What makes hydroprocessing different to other refining technologies?

Most of the people that have worked around refineries for some time, feel that they have mastered the basics of the major refining technologies and feel that they have some knowledge of the main strengths and vulnerabilities of those technologies.

Jeff Johns
Becht

Article Summary

In this blog, I’d hope to go beyond the basics and provide a deeper knowledge of hydroprocessing technology, including the many forms of hydrocracking and hydrotreating. I have spent most of my career working with hydroprocessing technology — including design, operations, maintenance, troubleshooting, and optimisation — and I’m still learning! I have especially enjoyed teaching classes and mentoring those working to increase their knowledge and understanding of this technology. I am thrilled to teach a class for Becht on this subject and hope you can attend sometime. In the meantime, I trust you will find this blog useful in your own quest for learning.

Let’s start with the question, “What makes Hydroprocessing different than other technologies?” Here are a few reasons:
Ï…    High pressures — 3,500 psig or more in some cases, but even units operating at a “low” 500 psig have pressures higher than most or all refining technologies.
Ï–    Exothermic reactions — Reactor temperatures can increase quickly to levels beyond design conditions and can progress to the point of melting piping and reactor shells if not mitigated.
ω    High levels of toxics — Most of the gas streams in hydroprocessing units contain high levels of H2S and NH3, making leaks and samples very hazardous if not handled correctly.
ξ    High levels of H2 — Hydrogen acts differently than some other gases — it heats up when pressure is lowered and often self-ignites when it leaks. It deserves respect that is not always appreciated.
ψ    Diverse corrosion mechanisms — Hydrocracking and hydrotreating units are a metallurgist’s dream as they often require the full spectrum of alloys to be used. Unfortunately, these units can also be a metallurgist’s nightmare when corrosion shows up in a surprising manner! Paul Simon wrote that there are “50 ways to leave your lover” and there are at least 50 ways for fluids to leave your unit through corrosion.

Clearly, this technology requires tremendous respect and attention, or unfortunate consequences can develop. At times, the consequences have led to injuries, fatalities, or substantial plant destruction.

I firmly believe and will show in this blog that hydroprocessing units can be operated safely and that these unique characteristics can be controlled and even used to advantage to meet the processing goals of producing valuable, premium transportation fuels without incident. I dedicate this blog to the goal of showing how to run safely and incident free.

I guarantee that there will be times that you will meet puzzling issues that will test your ingenuity. The odds are pretty good that somebody in the industry has seen these issues before and there is help available. I hope to document some of the puzzles that I have seen and helped to solve in this technology blog. I invite you to join me in spreading a deeper knowledge of these technologies to others. I welcome your comments and suggestions for this blog and encourage you to share your success stories and lessons learned the hard way.