Presentation: Dry Sorbent Injection Of Trona And Sodium Bicarbonate For SO₂, SO₃, NO_x And Mercury Mitigation

By Yougen Kong, PhD, SOLVAir Products, Solvay Chemicals, Inc.

"Dry Sorbent Injection of Trona and Sodium Bicarbonate for SO2, SO3, NOx and Mercury Mitigation" was presented at Power-Gen 2009 in Las Vegas, Nevada in December. In this case study, two boilers (Unit 2-140 MW and Unit 3 - 350 MW) at Constellation Energy's Wagner site burnt low sulfur coal. Trona was injected at the inlet of the air preheater, and the test results showed that the targeted 30% and 50% removal rates for SO2 for both units were successfully met with reasonable trona federates. Around 10% additional NOx were also removed.

While results showed that trona could meet established removal rates, when a higher SO2 removal rate was needed, it was clear that sodium bicarbonate would be the product of choice.

For Unit 2, around 90% of mercury was removed with trona injection alone. For Unit 3, only up to 80% of mercury was removed by PAC without trona. Over 90% Hg removal was realized by PAC with trona injection. The positive effect of sodium bicarbonate on Hg removal was also demonstrated and comparable to trona.

Read more...