Maintenance Dow Chemical, thorough and innovative

Dow Chemical in Terneuzen is a large production site. Dow is working toward a CO2-neutral future here. Among other things, it is developing an electric cracker together with Shell. In the meantime, ongoing maintenance is needed on the existing crackers, which are a crucial part of production. Thanks in part to Bilfinger ROB, this maintenance is not only thorough, but increasingly innovative.

In Terneuzen, Zeeland Flanders, the American company Dow produces a wide variety of plastics with more than 3,500 employees and 16 plants. The company has its own quay, where ships deliver raw materials such as crude oil or LPG. From there it goes to three large cracking plants, where the raw materials are heated to more than 800 degrees Celsius. Then the molecules disintegrate into various usable intermediates, such as benzene and ethylene, which are further processed into plastics in various plants.

Extreme heat

The extreme heat required to crack the raw products is produced in as many as more than 40 stoves. And when you know that one such stove needs servicing about every four to six years, you understand that there is at least one stove that comes up for maintenance every month. And that's where Bilfinger ROB comes in. They provide maintenance, from minor maintenance to complete replacement of the inside of the stove. 'The age and useful life of the cracking stoves determines exactly what maintenance is needed,' says deputy site manager Michiel Hendriks. 'Dow sees periodic maintenance of the crackers as an opportunity to have additional work done. Hence, in most cases it does not stop at just inspection and cleaning. In most cases, for us it involves replacing the coils anyway. These are large areas of pipe components, which we now have prefabricated. Once we have opened up the stove, we can remove the old coils and fit the new ones in one go. Then we make sure with welding connections that the new coils are perfectly connected again. In addition to the coils, we usually have work, for example, on the various valves that need to be overhauled. And for some time now we have also been working on parts from the convection section of the crackers. That too involves a lot of welding.'

Timely delivery

After safety, timely and high-quality delivery of the cracking stove is the most important thing for the customer. Because then they can continue production reliably. Decisive in this is the performance of Bilfinger ROB. 'We now do the maintenance work per cracker in about eight to twelve weeks,' says Michiel. 'And if it's just a recoil (replacing the coils) we do it in five weeks. Needless to say, Dow wants to get going again as soon as possible, and thanks to our years of experience, teamwork and thorough knowledge of the installations, we can do it in the shortest possible time.'

Recent innovations

Bilfinger ROB has been working at this Dow site for decades. In that time, ever newer and advanced working methods have been introduced. By Dow itself, but also by Bilfinger ROB. The most recent innovation is the introduction of a special type of welding tent. 'Because we do a lot of welding, we have to set up welding tents in different places,' Michiel explains. 'The welding tents ensure that you don't suffer from weather influences or fire hazards caused by welding spatters. They consist of a number of pieces of tarpaulin, which you use to close off the workplace. The dilemma here is that a closed welding tent falls under the "confined space" regime. That is, you turn it into a confined space and in it you are only allowed to work with a number of additional requirements. After a special study, we were finally able to set up a pilot where we place welding tents with special openings in them, making them not a confined space. You have to imagine that depending on the wind and the work, we always keep two hatches in the tent open. A simple solution with great benefits, especially for the welder who needs fewer measures to do his work as safely.'

Future

Because of the volume of crackers, Bilfinger ROB has an average of two crackers under maintenance every month. In addition to this ongoing work, four-year shutdowns always involve additional work. 'Moreover, Dow announced an ambitious roadmap last summer, to move to green hydrogen and electric crackers,' says Miechel. 'In this way, Dow is moving toward climate-neutral production by 2050. No doubt this will also create additional work. We are looking forward to it!'