BCE_Drying Tower_Vertical Demister
3Pages

BEGG COUSLAND ENVIROTEC LTD. Vertical Polygon Panel Demister for Drying Towers For safe removal & installation without tower entry A major issue in recent years in the Sulphuric Acid industry has been the development and use of equipment that can be more safely accessed and maintained, for example by avoiding entry into acid towers unless absolutely necessary. Drying Tower demisters – traditionally installed horizontally and with tight compression to the wall and section-to-section, to avoid gas by-pass – sometimes need regular cleaning and entry for diligent installation within the tower. Initial attempts to design an externally-removable horizontal demister had mixed success. An internal drawer framework did allow demister sections to slide in and out, and most interventions passed without tower entry. Problems increased with time, as the heavy demister sections began to distort the internal framework, making it difficult to reinstall and remove again (even sometimes requiring a man to go into the tower to help the process, i.e. self-defeating the concept). Problems were increased with larger plants and larger diameters of demisters, with excessively wide platforms being needed at the access points on either side of the tower, with very difficult to handle, heavy demister sections requiring extra manpower to get them in / out. A dirty demister is full of acid, and when sections were pulled out of the access doors for cleaning, there were inevitable falls of acid onto the areas below. A better solution was needed that avoided these problems, and which gave only the safety benefits intended. Externally Removable Vertical Polygon Panel Demister www.beggcousland.co

BEGG COUSLAND ENVIROTEC LTD. Begg Cousland, in association with Outotec GmbH of Germany, designed and developed the better solution, with a vertical demister orientation replacing the horizontal concept. By arranging the vertical demister as a series of panels, each with a top access door on the conical section on the top of the tower, a polygon layout proved to be an effective way to install them. A typical polygon arrangement is shown above left, with the panels approximately 1 metre away from the shell. The gas flow comes from underneath and passes from the outside of the polygon,...

BEGG COUSLAND ENVIROTEC LTD. In summary, what are the features and benefits ? 1. Lifting in and out vertically does not put any strain on the (polygon) framework inside the tower. 2. Lifting in and out can be done with 2 or 3 tower top mounted davits, saving crane and manpower. 3. When a dirty panel is just above the access opening, a drip trough can be attached to it’s bottom edge to avoid acid falling onto the areas below. 4. The demister mesh compresses and seals against the ‘U’ frame sides and bottom and the top access door in the traditional way to ensure no gas by-pass. 5. This...