Against the silver cat
Lobbe successfully uses gentle combination process for industrial cleaning at BASF Ludwigshafen
Almost inaudibly, Lobbe's own construction with three custom-made pipes on a frame of profiles moves a few centimetres to the right. Then the rotating pipes sink into the openings of a heat exchanger, it steams and hisses, water mist obstructs the view and millimetre-sized grains of silver catalyst are gently removed. All this happens at a dizzy height on the 18-metre stage of the Citral factory on the BASF site in Ludwigshafen.
The heat exchanger looks not entirely dissimilar to a household noodle. Its straight surface - called a mirror - is interrupted by thousands of round openings. These openings are thin tubes where the silver catalyst usually touches the liquid used to make citral, accelerating a chemical reaction. Citral is ubiquitous and found in almost every foodstuff; its bright yellow colour is used for desserts, vitamin tablets, but also animal feed. The heat exchanger here is only a small intermediate step in the production of citral.
The tubes of the heat exchanger , which is five metres in diameter, are only 38 centimetres long . Thesilver catalyst inside solidifies overtime due to the temperature difference and becomes as hard as concrete.
"The special task
The special task here is to clean the 34,000 pipes in such a way that
the hard mass of the catalytic converter disappears without residue
disappears, but at the same time the material of the
material of the pipes retains the surface quality. No easy
task when a great deal of force has to be combined with a gentle
process has to be combined," says Martin
Martin Bosch, head of the southern branch of Lobbe
Industrieservice GmbH & Co KG.
34,000 pipes are cleaned automatically in the Citral factory.
Lobbe's technicians therefore studied the conditions in detail beforehand. After initial scepticism
on the part of the customer, a simulation that Lobbe created in advance of the cleaning was convincing. The newly developed process is a combination of two proven methods in industrial cleaning. One of these is the Robotized Lance Frame, a five-by-five-metre gantry that encompasses all three axes - width, height, depth - of a heat exchanger. On this frame is a movable working head that is controlled by remote control. It is equipped with special nozzles that both propel the lances and remove the hard residues.
The rotation of the lances around their own axis makes the entire system highly effective, the principle is similar to a drill. The specialist, who controls the cleaning by means of remote control, can immediately see on the system's monitor whether the respective lances are still rotating or whether they have become stuck. The forces acting on the silver catalyst and heat exchanger tubes can be influenced by three factors. The water pressure, which in this case is about 1,000 bar. By way of comparison, a normal household high-pressure cleaner can reach a maximum of 400 bar, while industrial cleaners sometimes use up to 2,500 bar. The fact that the process is both effective and gentle is proven not only by the silver grains that are removed. Regular visual inspections with an endoscopic camera, as used in colonoscopy, also show that the pipes are free of residues and the inner walls are completely intact. After about three weeks of work, all those responsible agree: this cleaning was a complete success!
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