Feb-2024

Worker safety when entering reactors with an inert atmosphere (TiA)

The products from petrochemical processing touch almost every aspect of modern living. The importance of these products to industry and society emphasises the critical nature of facility maintenance and efficient turnarounds that keep production going.

Kevin Chase
Johnson Screens

Article Summary

The lost revenue and costs associated with shutting down a process for media bed changeouts, preventative maintenance, or repairs are significant. During these outages, every element of the turnaround must be carefully planned and executed efficiently by plant workers to meet tight schedules and get the plant back on-line. As a result, worker safety is always critical, especially when entering the confined space and hazardous environment inside petrochemical reactors. Injury or accidents of a worker can result in significant impact to workers, families, and project schedules.

Problem
Professional process engineers and managers in the industry are well-trained, knowledgeable, and equipped to comply with safety standards and guidelines from OSHA, API, NFPA, and ASSP/ANSI for continuous worker safety.1-4 They are trained to understand and mitigate the risks to workers and ensure that the processes and protocols in place are carefully followed to guarantee worker safety throughout turnaround activities.

Regulatory and industry safety standards for rendering the internal atmosphere of a reactor inert and allowing workers to enter the confined workspace are detailed and complex. After a vessel is purged and flooded with inert gas to mitigate potential explosions, many significant hazards to workers persist, including asphyxiation, working conditions, and changes to the internal atmosphere. Fortunately, several regulatory and recommended safety standards are in place to address and minimise these hazards.

Defined as permit-required spaces, OSHA 1910.146, NFPA 350 Standards detail the requirements of the written Permit-Required Confined Space (PRCS) Program that includes area identification and barriers, atmospheric testing, documentation, entry permitting and close-out, emergency retrieval, stand-by personnel, continuous environmental monitoring inside the vessel, vessel purging/inerting, ventilation, worker breathing equipment, personal protection equipment (PPE), worker communications, lighting, rescue and emergency equipment, and ongoing training.

API Recommendation 2217A references the above standards while providing additional details on each aspect, including maintaining the inert atmosphere with nitrogen and the potential hazards of ‘catalyst crusting’, testing, and mitigation.

Petrochemical plants are well versed in implementing these programmes and guidelines while ensuring they are followed for the safety of workers on the turnaround team and specifically those who will be entering these ‘entry permit required’ spaces to perform maintenance.

Challenge
Implementation and compliance with regulatory and industry guidelines for entering PRCSs is critical, yet complex and expensive to execute and implement. As such, companies are constantly evaluating their turnaround processes and procedures to determine if any changes can be made to minimise risk to workers and the necessity for implementing these protocols at various stages of the turnaround in fixed-bed reactors.

From a regulatory standpoint, anytime workers need to enter a vessel, the protocols for PRCS must be followed. Changing the media when it has reached the end of its useful life, for example, requires that workers enter the vessel to remove the hold-down screens or the manways in top screens to allow access for the media removal equipment.

Of course, once the media is removed, the vessel can be ventilated completely to create a safe and stable atmosphere where workers can enter the vessel and perform service or repair to the vessel internals. However, many hazards still exist, and once again the safety protocols and permitting process for entering the confined space must be followed.

With an eye on reducing costs, reducing risk to workers, and improving turnaround times, many companies and process engineers have begun to ask how the process for simple media bed changes can be simplified to eliminate the need for a worker to enter the vessel to remove the media. This would help to streamline the initial stage of the turnaround and shorten the overall process. In some cases, companies have already begun to mandate that employees not enter vessels when removing media during a turnaround. These corporate mandates create unique challenges for process engineering teams at the beginning stage of a turnaround.

Solution
Johnson Screens believes reactor internals can help processors maintain regulatory and corporate policy compliance while enhancing worker safety and has created unique solutions to address these challenges. These innovative new products will be highlighted in future articles.

References
1: API (American Petroleum Institute) Recommended Practice 2217A, 5th Edition, July 2017.
2: OSHA (Occupational Safety and Health Association) Standard 1910.146 Permit-Required Confined Spaces.
3: National Fire Protection Association, NFPA 350 – Guide for Safe Confined Space Entry and Work.
4: American Society of Safety Professionals and Approved American National Standard (ASSP/ANSI) Z117.1, 2022, Safety Requirements for Entering Confined Spaces.

This short case study originally appeared in PTQ's Technology In Action Feature - Q1 2024 Issue

For more information: kevin.chase@johnsonscreens.com