Reynolds Wrap Up: Substantial Changes Coming in API 751 on HF Alkylation Unit Mechanical Integrity Requirements and Expectations

Introduction

API RP 751 on Safe Operation of Hydrofluoric Acid Alkylation Units is in the final stages of revision before balloting and publication of the fifth edition of the standard. The largest changes pending are in Section 3 (soon to become Section 6) and Annex D (soon to become Annex G). This ‘Reynolds Wrap Up’ will highlight some of the most significant changes that are pending in the section on Mechanical Integrity, Damage Mechanisms and Maintenance Work Practices (hereafter referred to as the MI section). There are just over 130 refineries left in the USA and a bit over one third of them have HF Alkylation (HFA) units to produce a high octane gasoline blending component.

A task group (TG) of HFA MI subject matter experts (SMEs) with both API and NACE contributors has been busy over the last 2-3 years working on the MI section to update it in order to continue progress to enhance the process safety aspects of operating HFA units. The SMEs contributing to the new revision include those from operating companies and consultants with long experience in HFA unit design, processing, inspection and auditing. The majority of HFA operators are involved in the revision, bringing to bear thousands of hours of operating experience. Over the years since the publication of the fourth edition, owner-operators have made a lot of changes to continue to improve the mechanical integrity and process safety of operating their HFA units. The effort of this API 751 MI TG is to capture most of those improvements and standardize them for all to follow.

Some of the Big Changes in the Fifth Edition

From my perspective, the ten most significant changes being considered for the MI section (out of upwards to a hundred total) of API RP 751 in the fifth edition include: