Distributed Combustion With Swirl for Gas Turbine Application Using Low Calorific Value Fuel

Distributed Combustion offers significant potential for improved performance and near zero emissions for gas turbine and other industrial applications. Our quest for zero emission distributed combustion is further explored here by utilizing swirl to the flow. The beneficial aspects of distributed swirl combustion are examined with special focus on near zero emissions of NO and CO, and significantly improved pattern factor of the combustor using low calorific value fuel. Methane gas diluted with inert gas is used to simulate the low heating value fuel. A cylindrical geometry is used for combustor with air injected tangentially to impart swirl to the flow. The combustion behavior is evaluated using normal and preheated air at inlet to the combustor. Experimental results from the distributed combustor design using methane fuel showed low levels of NO (<8PPM) and low CO (∼21PPM) under non premixed conditions at an equivalence ratio of 0.7 and high heat release intensity of 36MW/m³-atm. With preheated air to the combustor, results showed overall NO levels of <15PPM and CO ∼12 PPM for non premixed combustion at an equivalence ratio of 0.6 under high heat release intensity of 27MW/m³-atm. Low heating value gas resulted in a dramatic decrease in NO emissions (30–50%) with minimal effect on CO for all the conditions examined here. Results obtained with different calorific value fuels on the emissions of NO and CO, lean stability limit and OH* chemiluminescence are presented.