Selective catalytic reduction in the exhaust gas train of a cement-clinker kiln uses multiple contact chambers containing vanadium pentoxide elements

摘要

Cement-clinker kiln exhaust gases at 1800-2000[deg]C. are dosed with ammonia and passed to contact chambers, preferably of 300-1000mm height, housing catalyst elements containing 3-10% vanadium pentoxide. Catalyst surface is maintained clear of dust by regular application of air blasts and sonic vibration. Independent claims are included for a rotary kiln arrangement which includes SCR (Selective catalytic reduction) contactor chambers in the exhaust gas train, in which air blast and sonic vibration equipment is installed to keep the catalyst surfaces free from dust accumulation. Preferred cleaning cycles are : air blasts of 60 - 600 second duration at 3-20 minute intervals, and sound vibration at volume of 90-170dB applied for 1-30 seconds at 10-30 minute intervals (claimed).