At the heart of an ethylene plant are huge cracking furnaces where hydrocarbons, such as petrol components and gases, are thermally cracked – broken down into simpler molecules – in externally heated pipes at high temperatures. In the upper part of the cracking furnace, steam is generated and the material to be cracked is preheated, with ﬂue gas at temperatures of up to +1,300° C.
The actual cracking process takes place in the combustion chamber of the lower furnace section. Here there are long tubes made of a special alloy in which the feed mixture is heated to around +850° C by means of large, gas-ﬁ red burners and thermally cracked. Following this stage, to stabilize the product mixture, the temperature is cooled extremely rapidly from about +850° C to about +400° C.
During the production of the 350 VEGAFLEX sensors, VEGA had to keep a close eye on the extreme challenges of the project. The level detection supplied must function reliably even at extreme process pressures and high ﬂuctuating product temperatures, as well as ambient temperatures below -50° C. Along with the special designs, process optimised, ready-to-install solutions are also an important factor for success. Obviously, any project supply to site requires meticulous timing for delivery. In this case, however, it was not so much the customer who needed this speed, but rather the special climatic conditions in that part of world: On average, the site on which the complex plant is being built can be accessed with heavy, oversized transport ships only 45 days a year – this is the only time the Tura and Tobol rivers are free of ice.