A technical review of ENAP’s Aconcagua refinery sulfur block – part one

The sour components produced in these units are processed in the following units:

• Sulfur recovery units (SRUs) 1, 2 and 3 (URA1, URA2 and URA3).
• Sour water stripper units 1 and 2 (SWS1, SWS2).
• Amine units (U500, U300, U950, U1700, U1800, U3000, U3200).

As of 2019, Chilean environmental regulations have undergone a series of modifications that have tightened the operation of the SRUs and their associated units. In order to be able to monitor these emissions, continuous emissions monitoring systems (CEMS) have been installed in all three URAs. Before these new regulations were introduced, the allowable quantity of sulfur (SO₂) emissions was 2190 tpy. However, since 2019, the regulations have established a decreasing limit with a target of 1145 tpy for 2023 (a reduction of 50%).

Moreover, during 2020 - 2021, the availability of the sulfur treatment system decreased considerably as a result of operational problems, load instability, maintenance shutdowns, early equipment and instrumentation failures, etc.

To investigate the causes of these increased emissions, as well as the reduced availability of the units, ENAP contracted Comprimo, part of the Worley organisation, to carry out an external technical review. This allowed a diagnosis of the system as a whole and made it possible to define short, medium and long-term plans to ensure the reliability of the units, maintaining their availability and compliance with current environmental regulations.

The technical review consisted of two one-week site visits, an operator questionnaire to evaluate the current knowledge of the design and operation of the environmental units, and a number of presentations and meetings to review past and current problems.

Comprimo prepared worksheets for each individual unit, as well as general worksheets that encompassed multiple units to provide recommendations for physical and operational changes. The worksheets outlined which aspects of the plant were impacted, as well as the severity of the current deficiency of the facility. The impact to the plant was segregated into the following categories:

• Efficiency = emissions.
• Reliability = risk of failure of equipment or instrumentation.
• Production = impact on total production of the refinery.
• Safety = protection of personnel and the public from harm.

This article was originally published in the February 2024 issue of Hydrocarbon Engineering magazine. To read the full article, sign in or register for a free subscription.

Written by Marco van Son, Ines Hernandez-Virla and Frank Bela, Worley Comprimo, alongside Xavier Pizarro, Sebastian Chaparro and Carmen Rodriguez, ENAP.

Read the article online at: https://www.hydrocarbonengineering.com/special-reports/14022024/a-technical-review-of-enaps-aconcagua-refinery-sulfur-block--part-one/