Frequently Asked Questions about Hydrogen Fluoride


Hydrogen Fluoride FAQs

Overview of how HF is used in refinery operations, with existing and proposed safety systems.

 

Will you continue to use HF?

The Refinery uses a process known as alkylation, with HF as the catalyst, to produce high octane gasoline. Rebuild plans include continued use of HF, which has been safely used at the Refinery for almost six decades. Additional protective measures have been installed and the Refinery is evaluating others to further enhance the safety of the HF unit. Pending regulatory approval, the additional measures will include:

  • Additional layers of water mitigation. The HF unit currently has a water system that includes a dedicated curtain and two water cannons, which are a highly effective method of addressing hydrofluoric acid vapors, if needed.
  • A Rapid Acid Transfer System which can quickly transfer HF to an independent secure holding tank in the event of an incident.
  • Enhanced leak detection, including a laser detection system.

If the Refinery's HF unit was safe, why are you putting in additional safety measures?

The HF safety systems in place in April 2018 operated as designed during the incident. There was no release of HF. The Refinery plans to enhance existing safeguards as a precautionary measure, after listening to concerns from the community. The plans are being reviewed with state and federal regulators.

What additional safeguards will be added to the HF unit?

While the HF mitigation system safely operated as designed during the April 2018 incident and no HF was released, additional safety features have been implemented and others are being evaluated. The plans are being reviewed with state and federal regulators and pending regulatory approval, the additional measures will include:

  • Additional layers of water mitigation. The HF unit currently has a water system that includes a dedicated curtain and two water cannons, which are a highly effective method of addressing hydrofluoric acid vapors, if needed.
  • A Rapid Acid Transfer System which can quickly transfer HF to an independent secure holding tank.
  • Enhanced leak detection, including a laser detection system.

What is alkylation and why does the Refinery need it?

To produce high octane gasoline, refiners use a process known as alkylation. HF is a catalyst used in the alkylation reaction to increase the rate of the chemical process, but is not consumed during the reaction. The HF alkylation unit gives the refinery the capacity to produce high octane gasoline which is an integral part of the Refinery's business.

What considerations went into the decision about HF?

Although HF is widely used in the refining industry, the Refinery explored possible alternatives and conducted a robust analysis of alkylation technologies that do not use HF. After a thorough technology review, engineering analyses, risk assessments and discussions with subject matter experts, the Refinery determined the alternative technologies — sulfuric acid and ISOALKY — were not proven or involved significant risks. It was determined that continued use of HF alkylation technology represented the best path forward for the Refinery. The existing HF unit has operated safely for almost six decades, and additional safeguards are planned as part of the rebuild project.

Why not use sulfuric acid, ISOALKY or other alternatives?

The two existing alternatives to an HF alkylation unit are sulfuric acid alkylation and ISOALKY. Converting an HF unit to sulfuric acid has never been done in the refining industry and would present substantial technological and operational challenges. The first commercial-size ISOALKY unit is being installed at a Salt Lake City refinery but is not yet operational. ISOALKY is an unproven, emerging technology and not currently suited for use at the Superior Refinery.

After thoroughly evaluating the alternatives, the decision was made to continue using HF at the Refinery. The existing HF unit has operated safely for almost six decades, and additional safeguards are planned as part of the rebuild and are being reviewed with state and federal regulators.

Will the Refinery be willing to switch to a new alkylation technology that doesn't require HF, if one becomes available?

The use of alternative technologies will be monitored and evaluated as they develop and are tested.

Have you obtained approval of state and federal agencies to use HF?

Rebuild plans are being reviewed with state and federal regulators. All necessary permits will be obtained prior to returning the Refinery to operation.

When will your HF upgrades be complete?

Some additional protective measures have already been installed. The further upgrades to the HF alkylation unit are part of the Refinery rebuild and will be implemented as the Refinery resumes operations in 2021.

The Refinery submitted its own risk analysis to the Environmental Protection Agency (EPA) showing how many deaths could result from an HFrelease. Shouldn't the community be concerned?

This refers to the Risk Management Plan (RMP) submitted to the EPA every five years. The EPA requests operators of refineries and other industrial plants to assess, for various chemicals including HF, theoretical risks for hypothetical worst-case scenarios, even if the scenarios are highly unlikely.

For the Refinery, the RMP documents the hypothetical potential impact of the release of the entire HF storage tank within 10 minutes. The analysis assumes an extremely unlikely worst-case scenario where the HF unit is full, is destroyed or substantially damaged during an incident, and where no safety systems are activated. It also assumes the weather pattern is stagnant (no wind).

The RMP is provided to emergency response agencies to assist in the development of procedures, training and programs which would be activated in the event of such an extreme incident, where none of the existing HF safety systems are operating. It is prudent to plan for worst-case scenarios, but they are unlikely.

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