Shutdown in 3 ... 2 ... 1
A chemical plant that is normally in operation round the clock seven days a week has now been shut down. However, it is still a hive of activity. Cranes and lifting platforms move into position. High-pressure water jets are targeted at dismantled parts. On the right, fitters are ensuring that flanges are correctly inserted. On the left, vessels, piping and valves are being tested, cleaned or even replaced. During the weeks of the plant shut-down, extreme concentration and precision are required – every day counts. Speed, efficiency and compliance with safety standards are essential.
A complex Undertaking
The law requires a chemical plant to be shut down for a general overhaul at intervals of between three and five years. The objective is to ensure that the strict requirements of the Operational Safety Ordinance (BetrSichV) are still met. For this purpose, a part or in some cases the whole of the plant is shut down for a period of between four and eight weeks and intensive inspections are carried out. About 1,500 to 3,000 experts may be involved in inspecting equipment, vessels, pumps and valves right down to the last detail, cleaning them and replacing them if necessary. Such projects are a nightmare for plant operators as they present a huge economic risk and can destroy hard-earned profits in the space of a few days. The requirements are comprehensive and laws and regulations are becoming increasingly stringent. At the same time, the time window allowed for shutdowns is becoming shorter and shorter. These factors all call for precise preparations, competent planning and reliable implementation at the same time as complying with all the relevant safety standards.
A Race against Time
Every day of a shutdown causes astronomic personnel expenses and losses may amount to about €100 million in the space of a few weeks. In addition, unforeseeable challenges often arise and need to be resolved in a very short space of time. This is why turnaround strategies are being continuously improved and call for intensive planning with advanced IT solutions to ensure that optimum preparations have been made for a major shutdown. Much of the work is carried out manually, which is why personnel requirements are so high. The work itself is physically demanding and there is often a shortage of experienced specialists. If plant operators are unable to meet the personnel requirements with their own employees, they often call in specialists from other countries. If external subcontractors are engaged, considerable problems may arise as they will not be familiar with specific conditions at the plant. In addition, work instructions are often only available in German. Language barriers may lead to defects in the work which is performed. Work needs to be carried out under tremendous pressure of time and there are often delays during shutdowns followed by malfunctions, additional non-planned costs and unproductive times. The objective is to avoid these serious consequences.
A Question of Reliability
Solutions need to be developed not only in order to minimize the economic risk but also to boost productivity and to shorten shutdowns at the same time as ensuring smooth and trouble-free implementation. For this purpose, new procedures at chemical plants should be investigated in order to refine operations in individual areas, to eliminate concerns and to ensure that manual work can be carried out as simply as possible using advanced tools. It is often not possible to determine whether the turnaround has been successful until the plant is recommissioned. Following recommissioning, there must be no leaks from flanges as these could mean that work would need to be repeated. In order to prevent incidents of this type, Atlas Copco is carrying out research work to ensure the highest possible security levels during recommissioning with its high-torque tools and software solutions.
No Game of Chance
A shutdown doesn't have to be game of chance. With many years of experience e.g. in the automotive industry, Atlas Copco Tools has specialized in offering reliable solutions in the areas of process safety, quality assurance and operator guidance. During a shutdown there are often changing locations with different requirements in terms of accessibility, material and torque range. Therefore, equipment must always be flexibly adjusted to a new bolting situation and brought mobile to the typical applications. Atlas Copco offers a large portfolio of solutions covering tightening torques up to 71,000 Nm.
Atlas Copco Tools offers a comprehensive portfolio of smart connected solutions such as a modular electronic torque wrench, an electronically controlled high-torque cordless nutrunner and scalable worker guidance. All the products are mobile, can be connected to each other without cables and can monitor all the work steps required. They communicate with each other and provide all relevant results on a shared platform which is independent from specific locations. Let us take a flanged joint in a chemical plant as an example: often, hazardous fluids flow through this joint. Following a shutdown, the joint must be reliably installed and free from any leakage. Clear visual work instructions provided by the SQS3 work guidance software package ensures that complex processes are presented in a simple way for the user, work sequences are defined and work results are verified. This approach minimizes the potential for human error and ensures that each defined work step is properly completed.
The ST-Wrench electronic torque wrench is well-suited for precise tightening tasks. It features a modular design which allows flexible adjustment of its length. This means that it can be adapted to a number of different applications depending on the torque and accessibility requirements. In addition, a wide range of tool attachments with RFID tagging is available for use with the ST-Wrench. These can be assigned to the various different types of flange. When the tool attachment is inserted into the unit, the appropriate pre-defined tightening program is activated. Alternatively, the tightening program can be selected by an integrated scanner ensuring selection of the tightening program independently from the operator and minimizing operator error in this area. The documentation of all relevant tightening results and the electronic merging of these results with component information on a higher-level platform ensures that the entire tightening operation is traceable. In addition, this data may be supplemented by user information. The user is informed about the results of the tightening operation on the display. In the event of tightening errors, the user can also be guided through a repair process.
Distances in a chemical plant often reach up to two or three kilometers, which can make a tight time schedule even tighter. This is why it is important to ensure that tools can be used flexibly and are mobile. Nevertheless, tools must be used in a secure process and the results obtained must be traceable. The SRB HA electronically controlled high-torque cordless nutrunner meets all these requirements. It could play a key role in avoiding unnecessary movement. The nutrunner is equipped with an on-board controller which manages communications with other systems and the documentation of all results. This allows more independent working in the field as it is not necessary to carry an additional controller and to ensure a power supply. In this case too, the controller ensures that the results are traceable and guides the user through the process. In the next issue of SYN], we will report in greater detail on the new model and the flexibility it offers.
Future-oriented solutions for chemical plants
The expertise of Atlas Copco Tools, with a broad portfolio of tools and software solutions, also includes the control of work sequences and the secure supervision and documentation of all assembly processes. The Atlas Copco Tools production optimization team can provide advice and support for the planning of work sequences, the selection of tightening strategies and tools to be used and for the design and testing of tightening operations. To meet the individual needs of customers and to help them master the economic challenges faced by plant operators, Atlas Copco Tools also offers the rental (Atlas Copco Rental) of tools and software solutions. This ensures the smooth and trouble-free implementation and timely completion of the project as well as the proper performance of all assembly processes and steps with improved profitability and maximum flexibility.