PROCESS FOR DENOXIFICATION OF OFF-GASES FROM ANNEALING AND PICKLING LINES, AND AN ANNEALING AND PICKLING LINE, ESPECIALLY FOR STAINLESS STEEL HOT OR COLD STRIP

摘要

Heat from waste gases leaving the annealing furnace (4), is supplied to waste gases from the pickling section (6) ahead of selective catalytic reduction (9) (SCR). Waste gases from both sources are combined and fed together to the SCR section. Waste gases from the pickling section are supplied with heat from the combined stream, before combination with those from the annealing furnace. Further variations based on the foregoing principles are described. Heat may be supplied in addition, from external sources. Gases from the pickling section are heated to a temperature of 140-280?C. The combined gases are heated to 200-360[deg], before the SCR section. The plant includes a recuperator for the heat transfer stage. The low temperature inlet is connected to the annealing section. The high temperature connection of the heat exchanger carries the combined flows. Between the outlet for lower-temperature gas leaving the heat exchanger (7) and the SCR plant, a burner, preferably a low-NOx burner, is used. The heat exchanger is of cross-flow construction. An independent claim IS INCLUDED FOR the corresponding annealing and pickling lines equipped for selective catalytic reduction.