Reformer Severity in an Octane Long World | RefinerLink

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Reformer Severity in an Octane Long World

By Ralph Laurel

Apr 19, 2019

Adapting refinery octane balances to changing markets.


With the introduction of more and more ethanol blends, the need for higher octane blendstocks has declined. The days of running max severity on refinery Reformer units are behind us. 

There are a few things to consider as you optimize operations around a new set of conditions.




H2 Yields

Lower Reformer severity on a means less hydrogen production. Depending on your refinery configuration that might just mean purchasing more hydrogen, but for many refiners the loss of hydrogen could mean a loss of hydroprocessing capacity.


If that’s the case at your refinery, make sure you’re weighing the options carefully. Increasing severity just for hydrogen might allow more cracked stock into finished distillate but it will also mean loss of reformate yields.


Turning reformate into LPG and hydrogen is often a losing proposition so make sure you’ve weighed that tradeoff carefully. In many cases



purchasing some higher octane blend components may actually be more economic than increasing severity on your Reformer Unit.


Catalyst Selection

The catalyst used in your Reformer unit was likely selected based on the typical severity the unit was run at. If the operating range has changed, it’s very probable that a different catalyst may be more optimal.


Evaluate new catalysts based on the reformer severity that you currently run and also the parameters that are most important in the new environment. If hydrogen production is more important than octane at your refinery, make sure the catalyst vendor is aware of this and is formulating the catalyst to your updated needs.



Reformer Feed Quality

Another variable to be aware of is the quality of feed to the Reformer unit. As octane becomes less valuable, factors such as reformate volume yield and benzene content become more of a driver. 

Feed tailoring remains a valuable tool to optimize refinery operations. While cyclohexane is a good reformer feed molecule, methyl-cyclopentane, on the other hand, is rather poor.

Both molecules boil in the same range, but many refiners do not have adequate feedstock molecular analysis to distinguish between the various types of hexane molecules. Understanding refinery constraints (i.e. H2 or Benzene) will dictate the correct operating strategy.


Identifying an alternate homes for cracked naphthas can also improve reformer yields, thus requiring lower reformer severity. Since the market favors distillate production over gasoline these days, refiners can become creative in how they manage cracked naphtha processing.  Simple changes such as increasing cracked naphtha routing to jet to displace straight run naphtha can improve reformer feed quality significantly.


Gasoline Pool Octane

Let’s admit it, gasoline blenders are a unique breed of people. In my years in the refining business, I have yet to meet a gasoline blender that’s readily willing to try new things. I don’t blame them, as they have a lot of stress and change that they are constantly managing.


That being said, this is now the most opportune time to challenge habits of your gasoline blender. I can guarantee you that your gasoline pool is not optimized, and the reduced octane requirement these days offers an opportunity to review the refinery blend strategy. 


It is possible to not have any octane giveaway in the gasoline pool, but still operate reformer severity higher than necessary. If your refinery currently blends straight run naphtha to the gasoline pool, ask yourself if this is necessary.

Is the reformer operating at minimum severity? Do you have octane giveaway without straight run naphtha blending?

Finding the proper balance between reformer severity, hydrogen yield, and reformate quality is often a complex optimization process that requires a good refinery LP and refinery economist.  Make sure you’re aware of the impacts of all these variables, and that you’re using that as a lever for optimization when possible.

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  • :   The U.S. gulf coast market appears to be rather volatile. The expected length in octane is not always materializing in lower premium spreads. I'm curious to hear about how the chemicals market is influencing octane demand.

    Sep 21, 2012

  • Dave Phillips :   Paul is quite right. With all the EtOH going to gasoline, one would think we are octane long. But all the shale and frac crudes are rich in LSR molecules that seem more than willing to soak up all the octane you can find. For years if not decades, octane had a value of $0.35/oct-bbl. Now, $2.00/oct-bbl is not rare. Also consider the amount of LSR or full range naphtha that is beingsold into the diluent market. Those bbls come right back as someone usually. Much of this depends on refinery config and especially location.

    Jan 29, 2014

  • John Stevenson :   Dave, I believe that the value of octane is also largely influenced by the large spread between LPG value and gasoline. If reformer severity is used as a handle to manage refinery octane balances, higher severity results in higher cracking of naphtha into C3 and C4s. In today's market environment, this spread is quite large as compared to a decade ago.

    Mar 18, 2014

  • Steve Mayo :   In the United States, it is much easier to change operations to push more low octane product. The skilled professionals on staff with these refiners, this will be an easy fix.

    Jun 07, 2015

  • Rick Rhead :   In a certain respect this was previously done years ago. With the requirements of oxygenates in the gasoline, the use of MTBE pushed refineries to operate in a lower octane mode with lower reformer severity. Hydrogen balance became important.

    Jun 07, 2015

  • Devin :   All of the public refiners (i.e., owned by public equities) claim we are octane deficient and that they are maxing out their octane and gasoline yields...but analysis of the units seems to indicate otherwise...anyone have thoughts?

    Nov 14, 2015

  • Richard Armstrong :   I believe that refineries in the US are generally octane long these days. The introduction of ethanol blending, and the increasing of biofuel mandates suggest that refineries should have plenty of octane capacity.

    Nov 15, 2015

  • Devin :   And yet, they all claim they are octane work indicates FCCs are producing ~46% cat naphtha nationwide, when they can produce 57% on avg., and reformers are running ~98 severity for octane and 81% for reformate production when they can run 100 severity and 84% reformate production by volume. Ethanol absolutely created an octane me, this summer, had more to do with FCC/Cat. Ref outages (most ever), Torrance, and Mexican spec production/exports due to LatAm outages, than the U.S. being "maxed" out on gasoline volume or octane production....yet all the refineries claim otherwise....

    Nov 15, 2015

  • Richard Armstrong :   Devin, what exactly are you getting at? Refining companies do not hold back operations without just cause or make uneconomic decisions. If an economic incentive exists, then efficient markets will make the right product supply to fit the demand. There are numerous other factors that exist that limit the ability to quickly supply a market. This can range from US Flag vessel availability, product specification constraints, number of refinery tank segregations, etc.. US companies also have the right to pursue product sales into foreign markets should those markets be attractive. Vice versa for foreign producers. Your use of the word "claim" suggest that there is some type of collusion or conspiracy theory going on. I highly doubt that is occurring. The oil industry is one of the most scrutinized industries in existence. I don't think that i'm being naive, but it'll be hard for the 'ole boys club to remain intact in today's society.

    Nov 17, 2015

  • Devin :   Hi Richard, absolutely not claiming any wrong doing whatsoever, simply that many say they are maxing out octane and gasoline, which implies the units are at max, but they are only at max given economic cracks, i.e., gasoline vs. diesel. It would be more accurate for them to say 'we are maxing out given current cracks, but we could do more if economics warranted.' So, when I investigated it, it would certainly appear that MGBC conversion ratios from feedstock are not being maxed at either the Cat Crackers or Reformers...

    Nov 18, 2015

  • Dave Pappal :   Octane requirements are driven by the product mix in the pool. Octane upgrading requirements are driven by the inherent octane of the blending components. Reformate is one component that has the ability to dramatically change octane with operating severity of the reformer. With significant ethanol in the pool, reformate octanes requirements were expected to be minimized. However with significant light tight oil being processed domestically, the need to blend low octane naphtha into the gasoline pool has increased the importance of high octane reformate to meet the overall octane requirements of the pool.

    Nov 29, 2015

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