INNOVATION July-August 2016

L eft : Addition of a second ammonia storage tank

increases ammonia storage and supply.

I nset : Ammonia detector measures and controls ammonia slip.

Vancouver facility by using back-cast tile mortar, which is more resistant to deterioration in the highest- temperature regions. Performance Summary Following start-up of the upgraded SNCR system in the fall of 2014, the NO x Reduction Project was fully commissioned on April 1, 2015, and NO x emission levels have been reduced to less than 135 mg/m³. This new operating level is more than 60 percent lower the current limit of 350 mg/m³, 29 percent

process and yields uniform flue-gas temperature and velocity profiles, which improves the performance and reliability of downstream boiler equipment. Integration with SNCR At the waste-to-energy facility, the LN™ process was combined with an upgrade of the SNCR system to further reduce NO x emissions and enhance the performance of the SNCR system. Upgrades to the SNCR system included increased ammonia storage, better mixing, and the ability to supply additional ammonia to the LN™ process. Other System Enhancements Combustion-Control System Modifications and Enhancements Modifications to combustion controls were made to integrate the combustion system and LN™ system. The modifications included control logic changes, process observation and tuning, and operator training to maximise the potential gains from the system. Boiler Protection Because the LN™ process diverts a portion of secondary air to a new tertiary level higher up in the furnace, a larger zone within the furnace is subject to high temperatures and low oxygen. While this larger high-temperature zone reduces NO x emissions, the system experiences more wear. This is mitigated at the Metro

below the limit of 190 mg/m³ in the draft operational certificate, and more than 50 percent lower than the 2013 average of 281 mg/m³. Prior to the NO x Reduction Project, the facility was producing approximately 0.8 percent of the NO x emissions in the region. Now it produces only 0.4 percent of those emissions. v Chris Allan, P.Eng., is a Lead Senior Engineer in Metro Vancouver’s Solid Waste Services Department. He has worked in the waste-to-energy field for more than 15 years.

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