Kinetic Study of Nitric Oxide Formation and Decomposition over Bed Materials in a Pressurized Fludized Bed Combustor.

The reaction rate constants of nitric oxide decomposition and nitric oxide formation over calcium oxide, calcium sulphate, silica sand and char were measured using a fixed bed reactor at a pressure of 788kPa and temperatures from 500 to 875°C . The reaction rate constant of nitric oxide decomposition over char at 860°C -788kPa was largest among the particles. It was 18.9 (s-1). Calcium oxide, which was produced by calcining limestone, promoted the oxidation of ammonia rather than the decomposition of nitric oxide. The reaction rate constants were 12.7 (s-1) and 1.3 (s-1) respectively. Calcium oxide promoted the oxidation of ammonia rather than calcium sulphate. The amount of calcium oxide must be reduced to decrease nitric oxide. The enhanced catalytic activities were due to active sites in the pores ranging from 400 to 1000A produced by calcination.