PTQ Q3 2024 Issue

Spaces 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 and service or repair the vessel internals. However, many hazards still exist, and once again, the safety protocols and permit - ting process for entering the confined space must be followed. With an eye on lowering costs, reduc - ing risk to workers, and improving turn - around 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 ves - sel to remove the media. This would help to streamline the initial stage of the turnaround and shorten the over - all process. In some cases, companies have already begun to mandate that

Figure 1 Anytime workers need to enter a vessel, the protocols for Permitted- Entry for Confined Spaces must be followed

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 envi - ronmental 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 1 references these stan - dards 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, specifically those who will be entering these ‘Entry Permit Required’ spaces to perform maintenance (see Figure 1 ). The challenge Implementation and compliance with regulatory and indus - try guidelines for entering PRCSs are critical yet complex and expensive to execute and implement. As such, compa - nies 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 implement - ing 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 Permitted-Entry for Confined

employees do not enter vessels when removing media dur - ing a turnaround. These corporate mandates create unique challenges for process engineering teams at the beginning stage of a turnaround. The solution Johnson Screens was approached to develop new reac - tor internals that will help process engineers comply with corporate mandates for reducing the risk to workers and the company to reduce the need for confined space entry for media bed changes. Innovating to meet this challenge required a new approach to standard hold-down screen designs that have been used for decades. In fixed-bed, downflow reactors that utilise hold-down screens at the top of the bed, accessing the media to change the bed requires first removing the hold-down screen from the vessel. Traditionally, this requires a worker to enter the confined space of the vessel to dismantle the manway in the centre of the screen by removing the bolts that secures the manway. For ‘floating’ hold-down screens, which sit directly to the top of the media bed, workers must enter the vessel to dismantle the entire screen, bolt-by-bolt, and remove the components through the vessel manway. Entering the vessel requires significant preparation, and although the vessel is flooded with inert gas to displace the volatile gas, risks to workers still exist due to low oxy - gen levels and continuous off-gassing from media while the work is being performed. Senior process leaders have concluded that this initial stage can be eliminated and have started to mandate that workers will no longer be allowed to enter a vessel just to remove a screen or a manway prior

PTQ Q3 2024