Emissions from the main stack of a modern recovery boiler are very well under control. However, a major source ofTRS and particulate emissions is still the dissolving tank vent stack. This vent stack is also often the only visibleplume coming from the recovery boiler. Until recently, due to their difficult nature, there was no effectivetechnology for eliminating these vent gases.Due to extremely tight overall TRS emission limits, dissolving tank vent stack emissions posed a serious problemfor Aracruz. During the recent retrofit of existing recovery boiler “C,” they decided to incorporate Andritzdissolving tank vent cooler technology.The new dissolving tank vent cooler technology solves vent stack emission problems by conditioning the dissolvingtank vent gases and using them as combustion air in the recovery boiler. With proper design, the potentialoperational issues and difficulties that could be expected can be mostly avoided.This paper discusses the design and operational aspects of implementing dissolving tank vent stack coolertechnology in an existing recovery boiler in Brazil. Mill operational experience with the system is discussed andinformation of actually achieved performance is given.
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