How to Make the Optimal Use of Scheduled Plant Downtime

A regular large-scale inspection of a refinery took place at Mineraloelraffinerie Oberrhein (MiRO) in Karlsruhe, in the spring of 2015. All 41 process plants in No. 1 Works as well as three plants in No. 2 Works were at a standstill for four–six weeks. During this time much more took place than just the fulfillment of legal requirements: The plants were cleaned, repaired and underwent further technical optimization and testing to ensure that they would run reliably and efficiently in the years ahead.

Within the scheduled downtime lasting approximately six weeks, 110 items of processing technology in the refinery (known as columns), 570 tanks, 950 heat exchangers and 1,200 safety valves had to be inspected. More than 150 technical experts, inspectors and materials testers were in action. A total of 2 million man hours were worked. During the core phase, the MiRO team received support from considerably more than 5,000 employees of partner enterprises from around 120 companies under contract – also including all local partners with framework contracts.

Among these were the automation specialists from Rösberg Engineering, who had been on board since the early 1960s, when the refineries first arose at the Karlsruhe location, at the intersection of important pipelines.

I&C – safety inspections during the startup and shutdown processes

During the shutdown time in spring 2015 the specialists from Karlsruhe were concerned mainly with tasks in two areas: The I&C safety inspections to be conducted during the startup and shutdown processes, and the realization of various plant optimization projects. These included, for instance, extending the plant by individual SIL–compliant measuring points, and also the new installation of a complete heat recovery boiler system.

The safety inspections covered all the emergency switches as well as the measuring equipment e.g. for temperature and pressure. Safe plant operation is only guaranteed if alarms and emergency switches are triggered whenever measurements exceed or fall short of the specified limit values. However, the planning and realization of appropriate tests is no small matter: The individual test steps need to be precisely scheduled, i.e. they have to be integrated in a logical sequence into the shutdown and startup processes of the plants and plant components.

Tailored for Engineering and Operational Requirements

Process plants are not simply switched on and off suddenly, but in a specific order which is right for the process concerned. When testing the individual components, the relevant inspection instructions have to be observed and all steps of the inspection have to be documented in a detailed and legally compliant way, including the necessary loop checks.

Fig. 1: The refinery MiRO in Karlsruhe: Optimal use was made of the shutdown time in spring 2015. Not only inspection by the TÜV (Technischer Überwachungs- Verein) was on the agenda; many individual projects were also realized. (Source: MiRO)

The conditions for inspection of the I&C safety functions in Karlsruhe were good. There were two reasons for this. At MiRO there is accurate, up-todate documentation for the whole plant with its more than 70,000 measuring points – and this documentation is available from every workplace, thanks to the I&C-CAE system ProDOK (see Technology 1, Fig. 2).

Fig. 2: The I&C-CAE system ProDOK is specifically tailored to the engineering and operational requirements of control systems in process plants and ensures rational, integrated planning and consistent documentation. (Source: Rösberg)

ProDOK is specifically tailored to the engineering and operational requirements of I&C systems in process plants and ensures rational, consistent planning and documentation, because it enables an integrated planning process with unified rules, covering the whole life cycle of the plant.