Check, Replace, Renew – A look inside a chemical plant’s turnaround activity
By Hanno KurzejaEngineering Industry Machinery and Equipment Maintenance Operations Preventative Maintenance Manufacturing chemical plants shutdowns turnarounds
An on-site visit at a Dow turnaround in a chemical plant in Böhlen, Germany, reveals the complexities of a well-planned turnaround.
When some machines rest it’s when others are running at peak levels: during a so-called turnaround in chemical plants, as it took place in Böhlen in September 2015, this is what happens every three to five years. Installations, compressors, pumps, and turbines stand still, but cranes and lifting platforms are on the move – during the safety inspections by TÜV SÜD Chemie Service and during clean-ups, repair and renewal works.
“Where the cranes are is where the action takes place,” says Reiko Hass, turnaround manager in the Dow plant in Böhlen, during the inspection of the premises of the chemical plant near Leipzig. The 320 ha large premises is currently covered in cranes and scaffolding. This is why riding on bikes, other than usual, is forbidden. About 30 cranes stretch up into the blue sky. Disassembled parts are lying around everywhere – from fittings to pipes up to boilers.
The regular shutting down of chemical plants is called turnaround or (large-scale) shutdown. The term “turnaround,” which is mostly used in Böhlen, in particular highlights the long lead time of 30 months. It starts right after the last turnaround. Furthermore, this suits that each single part is turned around, that is, disassembled, maintained and reassembled.
The term “shutdown” however, refers to the downtime of regular operation: usually, these installations are in operation for 24 hours, seven days a week and only a few people enter the premises. But every three to five years the installations are shut down in order to carry out statutorily prescribed and other inspections – mainly based on industrial safety regulations – as well as repair works. The period is calculated based on the measures “relevant for the turnaround” since the last turnaround: in this case 1.5 months.
Usually, almost 600 Dow employees and an external service team of 300 persons are working at the location; however, during the large-scale shutdown, another 1,500 employees from various companies are working there as well. Many of them go there every five years. And despite everything being strictly organized and monitored by security guards, the atmosphere is concentrated and familiar.
But next to personal efforts, an extreme amount of logistics is needed for the project, not only with regard to inspection and repair works. “Everything needs to be planned up to the cutlery,” says Hass. The materials storage covers for this period, among others, two tents with 240,000 parts, 290 shower and changing containers, 50 containers for granting the work permit on site, 63 office containers and a kitchen tent. For the access to the premises, not only a large car park was created, but also additional traffic lights installed.
The heart is the cracker
It is noisy during the round tour, a rattling thunder in the background: the “washing machine” is in full swing. It cleans materials by spinning it together with gravel. At some locations it smells of caustic soda from the cleaning – “not dangerous,” says Peter Goth. Here, cleanliness is a part of safety. The TÜV SÜD Chemie Service expert witness has been working for 35 years for the chemical plant in Böhlen. Until 2009, he was working at the self-monitoring at Dow, from which this TÜV SÜD Chemie Service location emerged. Three to four employees are always on site. According to his own words, Peter Goth fell in love twice: once with his today’s wife and once with the cracker on site – there is a reason why it is called the “heart of the plant”.
In the cracker, petroleum is cracked into hydrocarbon compounds – ethylene and propylene – in 15 furnaces at around 800 °C, basic materials for the plastic production. Petroleum is delivered via a more than 430-km long pipeline directly from the harbour in Rostock to this plant. The cracker is the heart of the Dow Olefineverbund in central Germany. It supplies the plants and installations in Schkopau and Leuna with intermediates, which are further processed and made into plastics.
Also within the plant in Böhlen, several installations depend on the cracker, especially since it produces the process steam for further installation parts. “When the cracker coughs, everyone coughs,” says Olaf Fuchs, head of Plant Monitoring Central Germany at TÜV SÜD Chemie Service. For this reason, all other installations and parts need to be shut down when the cracker needs maintenance. Shutting down and cleaning all installations alone takes 10 days. The oldest parts of the cracker, located in the traditional plant founded in 1921, are older than 40 years, that is, they are from 1975. This makes it even more important that it is regularly checked to consider which parts need to be replaced or repaired.
1,200 to 1,500 jobs, 25,000 sequences
The cracker’s powerhouse is the most active today. One worker is measuring the turbine’s bearings, others are working on the fittings. “Here in the heart of the plant only highly qualified experts are at work,” says Hass. The different trades and employees jointly dismantle the affected parts completely, check, replace or renew parts and reassemble everything afterwards – subject to the strictest safety regulations.
In order to ensure smooth procedure, comprehensive and thorough planning is required. The colleagues of the turnaround team need to co-ordinate 1,200 to 1,500 jobs with a total of 25,000 sequences, that is, individual tasks. All depend on each other. “There is no point in bringing all these people here to have them check something and then there is no security guard,” says Hass. “To ensure that the colleagues can start their work, security guards, a crane, scaffolding and the right material are needed.”
Planning is co-ordinated months in advance and documented in a complex project plan. The particularities for the Dow turnaround in Böhlen are that all parts, also micro-parts are planned and ordered in advance. Thus, no waiting times arise. Every evening they check whether the plan was met in terms of safety and effectiveness. For deviations, good reasons must be stated. After all, the project involves high costs for Dow.
Each day, the plant usually makes a turnover of about one million euros. For a shutdown of 50 days, this means a loss of 50 million euros. Plus the investment of 42 million euros for the turnaround and technical innovations, such as the step-by-step introduction of a new process control system. Thus, the shutdown costs 92 million euros.
Safety ranks highest on the agenda. From the security company alone, more than 100 experts are on site and more than 2,500 safety trainings were carried out. The Safety Shop has 8,300 items available for the employees’ equipment. TÜV SÜD Chemie Service has 13 engineers participating in the turnaround, at a maximum eight at the same time. Without them, the project wouldn’t take place: the TÜV SÜD Chemie Service inspections are top priority as they are statutorily required. These are 80 per cent of the turnaround’s work packages. And according to Hass, they constitute the “largest challenge.” This comprises the corrosion monitoring. For example, this year, the supporting poles of 10 containers need to be replaced due to corrosion: for ten containers a total of 100 support poles have been replaced. For the TÜV SÜD Chemie Service expert, this meant 10 folders with inspection documentation for Dow.
Decisive for the inspections by TÜV SÜD Chemie Service is the Industrial Safety Regulation including explosion protection, which is now regulated in the Ordinance on Hazardous Substances. This, for example, plays a role for agitator vessels. But also company rules are important. The U.S. company attaches great importance to safety so that the requirements partially exceed the statutory requirements.
While shutting down the installations is most critical due to the ongoing production processes at the beginning, the most decisive weeks are the three subsequent weeks during which TÜV SÜD Chemie Service can carry out their work. Here too, no investigator can enter a vessel for an internal inspection before release measurements were carried out and proof is provided by means of gas measurements that all critical values are met. This is why such inspections are prepared overnight or in the morning between 3 a.m. and 6 a.m. Furthermore, a safety guard must be within sight during the inspections.
The inspection obligations are flexibly defined by the operation based on the statutorily permitted framework. For example, vessels under pressure need to be inspected at the latest every five years. However, if the TÜV SÜD Chemie Service experts conclude that safety is not guaranteed for the period, the inspection periods must be shortened. It is only possible to extend the inspection period to a certain degree in exceptional cases.
This year’s turnaround is smaller than usual in terms of scope, but: “When some installation parts are still okay, coordination is even more challenging, in particular with regard to safety,” says turnaround manager Reiko Hass. But what makes it a bit easier for the TÜV SÜD colleagues: more internal inspections are carried out – and less of the more complex pressure tests. “We will have to face them in the large-scale shutdown in five years time,” says Olaf Fuchs.
Experience is what counts
Olaf Fuchs from TÜV SÜD coordinates the inspection works. Just like Reiko Hass, he starts working on the shutdown project long before it starts and continues his work afterwards. The graduate engineer has his office in Schkopau and also co-ordinates the regular TÜV SÜD inspections during ongoing operation. During the turnaround he co-ordinates the 13 TÜV SÜD experts from Schkopau, Frankfurt and Dormagen, who travel to Böhlen for the specific tasks: which specialist is needed when? Where will he be accommodated and with whom can he share a car? The hotels in the area are booked months in advance, carpools organized. “The colleagues volunteer for the turnaround,” says Olaf Fuchs. “Here they can meet colleagues from other locations, gain experience and exchange know-how.”
Noteworthy: Nearly all colleagues are older than 40. “Especially in a plant with tradition as it is the case in Böhlen, experience plays an important role,” says Olaf Fuchs. He is convinced that without the practical long-time experience in the chemical industry, the employees wouldn’t be able to correctly classify the corrosion stages. “For example, a welding seam from the past cannot be compared with the machine-created seams from today and still it can be integer,” he says. And in case of wrong findings, “a huge machinery would be initiated unnecessarily.”
Shortly afterwards, the whole team from TÜV SÜD Chemie Service gathers with Goth to talk about a leakage at a heat exchanger’s welding seam. The specialists find a reliable solution that doesn’t endanger the scheduled completion date. Peter Goth wants to quickly go and take a look at the situation himself. There, employees from different companies stand around the heat exchanger. He discusses the result with them. Peter Goth, who will retire soon, says later: “I’m 60 years old, but I would be happy to realize another 10 turnarounds with this team” – and of course with his great love, the cracker.
Hanno Kurzeja is head of Department Marketing & Sales, TÜV SÜD Chemie Service GmbH. For more information, visit www.tuev-sued.de/chemieservice.