The customer selected Envitech to redesign and supply a scrubber to be retrofit into the existing system. The scrubber inlet was replaced with a high efficiency Hastelloy Venturi scrubber for particulate removal. The Venturi length was significantly decreased and oriented at an angle to the entrainment separator inlet. The shorter distance and angled orientation significantly reduced the duct run from the calciner outlet to the scrubber inlet, minimizing fouling potential.
The top of the entrainment separator was replaced with a packed bed absorber to neutralize and remove SO2. Structural modifications to the existing vessel ensures the new packed bed is well supported.
After the Venturi, the gas enters the bottom of the packed bed and travels vertically upward, counter current to downward flowing water. Excess water from the Venturi and the packed bed collects in a common sump. Caustic solution injected into the recirculation line neutralizes acid gases. Liquid recirculates back to the Venturi throat and top of the packed bed. The gas passes through a vertical entrainment separator above the packing to remove water droplets before exiting the system.
The scrubber was put into service in early 2021. A continuous emissions monitoring system (CEMS) confirms emission limits are met. The duct clean out time has been reduced from 24 to 36 hours to < 1 hour. System uptime has improved from < 60% to > 80%, enabling higher production capacity. The Venturi scrubber is significantly smaller in size, making replacement cost less expensive. The scrubber is designed to meet the process conditions below:
Click on the link below to download literature about the catalyst Calciner scrubber.