From Aachen to Anatolia – a field report

As a student you learn something in lectures about the ­theoretical connections of large-scale processes. For example, you know how a ball mill works and you are able to calculate retention times in reactors. But how is all this in reality? Do the plants really work as you expect based on the knowledge acquired in lectures and exercises? And, not least, what is the work in a factory like, what are the prospects ­after university? To take part in ­excursions is a good opportunity to get answers to these or similar questions.

In May 2008 AVT – Aachener Verfahrenstechnik (Aachen Process Engineering), which includes all chairs of process engineering at the RWTH-Aachen (Aachen College of Advanced Technology), offered such an excursion that was organized by ZKG Inter­national. The destination was the Dyckerhoff Lengerich cement works (Fig. 1). Various other companies were also represented, which are active in the sector of cement plant engineering.

Before the excursion, however, my fellow students were not very enthusiastic about this event: “Why go to a cement factory – there everything is dusty and old-fashioned!” Nevertheless, there were enough students to take part in the two-day event. The production processes of cement ­making were explained in various lectures, and the participating companies introduced themselves and their products. A special highlight was the plant tour through the cement factory, which was impressive alone because of the size of its individual parts.

Soon it turned out that the plants in a cement factory are continuously updated and that on closer inspection such a factory is not old-fashioned at all. During the excursion as students we had many opportunities to contact the representatives
of the various companies both during the breaks between the lectures and, in particular, during the joint dinner that ­finished late after midnight – because the restaurant wanted to close.

I personally established contact with the Cologne-based company KHD Humboldt Wedag GmbH. During the excursion I became enthusiastic about the possibility to take a closer look at the planning and commissioning of such a large plant. Thus, I got the opportunity to do an internship for several months at Humboldt Wedag, the first two weeks in manufacturing and then in thermal process engineering. This also included a stay in Turkey during the commissioning of a cement factory (Table 1).

I had to do a definite job during my internship. Flow measurements were to be carried out on the new PYROFLOOR^® clinker cooler in the Maras cement works of KCS (Fig. 2). This was a completely new plant for which Humboldt Wedag supplied the “thermal line”, i.  e. the cyclone preheater including calciner, rotary kiln and clinker cooler.

After a general introduction into cement making, the measurements had to be prepared and planned. What are the measuring instruments available, which location is best suited for the measurement and how to carry out the measurements correctly? All this had to be done before going to the southeast of Turkey via Istanbul.
On site first gauge connections had to be arranged on the cooling air ducts before starting the measurements (Fig. 3). In addition to the measurements to be carried out, fortunately there was enough time to “ look over the shoulders ” of co-workers to get an impression of what kind of work has to be done during the commissioning of such a large plant. Furthermore, it was possible to have a closer look at a cement factory over a period of several weeks. It was especially impressive to have the opportunity to set foot in plant parts, which are not accessible during normal operation. It makes quite a different impression to go through the cooler and look at the burner pipe and the kiln from there instead of looking at the installations only from outside knowing that normally there are temperatures of considerably more than 1000 °C!

During my stay at the factory they were still working at many locations (Table 2). Interlocking tests were carried out, measuring systems were commissioned or the last metres of pipelines were installed. It was clearly evident that the highest priority was to “get the plant running” as soon as possible. Since a lift in the preheater tower is not a prerequisite for this, we had to use the stairs! Only in this way is it possible to get a correct impression of the plant – the height of the preheater tower was more than 120 m. The participating companies, though sometimes competitors, had to cooperate as smoothly as possible. This clearly showed again that the design of a cement factory has to be understood as a sequence of interconnected processes. For example, it doesn’t make sense to ignite the burner if there is no raw meal available.

Altogether, this was a very good opportunity to take a look at the daily routine of an engineer at a plant engineering firm and to find an answer for myself to the question: “Cement – is it something for me?” Therefore, many thanks to Humboldt Wedag GmbH and, in particular, to the department of thermal process engineering!