The Case for Continued Use of HF Alkylation in Refining

Mark Green
Posted May 22, 2023

Let’s talk alkylation.

In refining, alkylation is critically important to produce the cleaner-burning fuels we have today – fuels that coupled with new engine technologies have allowed passenger vehicles to be more than 98-99% cleaner for most tailpipe pollutants compared to their forebears of the 1960s, according to EPA.

Alkylates have a high-octane number and low sulfur content, making them essential to complying with government fuel regulations.

They’re formed by reacting two light olefins together in an alkylation unit, using one of two possible catalysts – sulfuric or hydrofluoric acid (HF). Nearly 90% of refining capacity in the U.S. occurs at refineries with alkylation units, and about 50% of them use HF as their primary catalyst.

That’s all pretty technical; what everyone needs to know is that EPA could require refiners to shift away from HF alkylate – even though HF alkylation can be done safely, efficiently and is critically important in reducing U.S. emissions.

A recent analysis found that replacing all U.S. HF alkylation units would cost a staggering $12 billion to $19 billion – which could result in refineries being closed. HF alkylation refineries currently support more than 447,000 jobs and contribute directly and indirectly more than $119 billion to the U.S. economy. Losing any portion of the refining sector would not be good news for U.S. energy, the economy and American motorists.

Because of the above, API urges policymakers to allow the continued safe use of HF alkylation in its 2023 State of American Energy report. Exempting refineries from the most expensive part of EPA’s latest Risk Management Plan proposal is a key element in the U.S. House-passed H.R. 1 energy package and should make its way through the legislative process.

Risk analysis expert Jatin Shah of BakerRisk wrote recently for RealClearEnergy.com that preserving HF alkylation makes sense from a safety and risk perspective, noting that:

• Alkylate and its catalysts, including HF, are irreplaceable in producing clean, high-octane gasoline that are critically important in reducing vehicle emissions. Without alkylate, it wouldn’t be possible to produce gasoline to the strict environmental specifications of states like California.
• U.S. refineries in the U.S. have decades of experience using and managing HF safely, dating to World War II.
• Because of the specific challenges posed by HF, refiners have built upon requirements set by federal and state safety programs, including EPA and the Occupational Safety and Health Administration programs.
• API Recommended Practice 751 includes specific instructions around HF feedstock transportation, workforce training and recommended mechanical and technological HF safeguards. RP 751 is constantly being improved, having gone through five revisions since its original publication.
• Refiners use HF-specific leak prevention and detection systems – including double-sealed pumps; acid-detecting paint; HF point sensors and perimeter detectors; remotely activated block valves to isolate HF; rapid transfer systems to quickly move HF away from the area of a release; and water mitigation systems to neutralize any escaped vapor.

API has been conducting Process Safety Site Assessment Program (PSSAP®) assessments for companies using its HF/RP 751 protocol for more than a decade. With each revision to the standard, API has updated assessment protocols so that the latest requirements in the standard are considered in the assessments.

To date, API has conducted PSSAP assessments at sites representing more than 70% of the throughput that is produced using HF alkylation technology. API has seen almost all sites improve scoring since the program was launched – showing that refineries are increasing performance as well as their conformance to the industry standard.

Shah writes that based on his experience, the “refining industry has a strong case for continuing to use the chemical (HF), because a forced transition away from it would hamper U.S. fuel production and threaten critical gasoline supplies.”

Such a transition looks harmful to the sector and Americans – especially given the industry’s ability through RP 751 to mitigate the minimal risk associated with HF alkylation. Will Hupman, API vice president of Downstream Policy:

“Fuels produced by HF alkylation are a critical piece of the gasoline supply and cannot be easily or rapidly replaced with alternative technology. Refiners take HF alkylation safety seriously. Refiners follow a stringent refinery practice (API 751) so that these units are operated in the safest manner possible and adhere to the highest standards for operating procedures, emergency response, safety systems, equipment design, and mechanical integrity work practices. History shows that this approach is working and working well. Between 2016 and 2020, there have been only four incidents involving HF and none resulted in injuries to the public, offsite deaths, offsite property damage, shelter-in-place, or evacuations. This is attributable, in part, to the evolving recommended practices for HF alkylation units, in API 751.”