Nitric Oxide Pathways in Surface-Flame Radiant Burners

Nitrogen oxide (NOx) formation in surface-flame burners is studied. Surface-flame burners are typically made of metal fibers, ceramic fibers, or ceramic foam and provide radiant flux with low pollutant emissions. A one-dimensional model represents combustion on and within the porous medium using multistep chemistry, separate gas and energy equations, and a radiatively participating porous medium. We describe experimental measurements of NOx profiles above a surface-flame burner and compare them to model predictions. The model predicts NOx concentration with reasonable success. Deviations between model and experiment are primarily the result of heat loss in the experiment that is not considered in the model. Reaction rate analysis is performed to identify the chemical kinetic source of NO in the flame. Zeldovich NO is significant only at the highest firing rate studied (600 kW/m2, ϕ = 0.9), where it is responsible for 50-60% of the total NO. At the lower firing rates (200 and 300 kW/m2, ϕ = 0.9), where total NO is low, nearly all of the NO is formed in the flame front. Zeldovich NO accounts for 20-30% percent of the total NO, the Fenimore pathway accounts for less than 10% of the NO, and 50-75% percent of the NO is formed through the NNH, N2O and other paths. Sensitivity analysis shows that NO production in the flame front is most sensitive to NNH+O = NH+NO, with CH+N2 = HCN+N having the second highest sensitivity coefficient. At the lower firing rates NO emission is insensitive to porous medium properties, while at the high firing rate NO emission is slightly sensitive to porous medium properties

Achievement of Low Emissions by Engine Modification to Utilize Gas-to-Liquid Fuel and Advanced Emission Controls on a Class 8 Truck

A 2002 Cummins ISM engine was modified to be optimized for operation on gas-to-liquid (GTL) fuel and advanced emission control devices. The engine modifications included increased exhaust gas recirculation (EGR), decreased compression ratio, and reshaped piston and bowl configuration

DEVELOPMENT AND DEPLOYMENT OF ADVANCED EMISSION CONTROLS FOR THE RETROFIT MARKET

Bringing a diesel retrofit product to market involves two primary phases: development and deployment. Critical product development steps include technology selection, system integration, laboratory and durability testing, and regulatory agency verification work. This initial product development phase is then followed by a deployment phase, which consists of building and managing the infrastructure for installation, distribution, service, sales and warranty support. Building relationships with regulators and air quality program developers is also a critical aspect of the deployment process. A successful path to market requires close cooperation between developer, distributor, customer and regulator

Controlled oxidation of iron nanoparticles in chemical vapour synthesis

In the present study, iron oxide nanoparticles (primary particle size of 80-90 nm) with controlled oxidation state were prepared via an atmospheric pressure chemical vapour synthesis (APCVS) method. Iron pentacarbonyl [Fe(CO)5], a precursor material, was thermally decomposed to iron in the APCVS reactor. Subsequently, the iron was oxidized with controlled amount of oxygen in the reactor to produce nearly pure magnetite or haematite particles depending on the oxygen concentration. Size, morphology and crystal structure of the synthesized nanoparticles were studied with scanning mobility particle sizer (SMPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). In addition, thermodynamic equilibrium calculations and computational fluid dynamics model were used to predict the oxidation state of the iron oxides and the reaction conditions during mixing. Aggregates of crystalline particles were formed, determined as magnetite at the oxygen volumetric fraction of 0.1 % and haematite at volumetric fraction of 0.5 %, according to the XRD. The geometric mean electrical mobility diameter of the aggregates increased from 110 to 155 nm when the volumetric fraction of oxygen increased from 0.1 to 0.5 %, determined using the SMPS. The aggregates were highly sintered based on TEM analyses. As a conclusion, APCVS method can be used to produce nearly pure crystalline magnetite or haematite nanoparticles with controlled oxidation in a continuous one-stage gas-phase proces