Comparison of CO and NOx concentrations from a 20 kW boiler for periodic and constant wood pellet supply

Abstract

The impact of the fuel feeding mode (continuous or periodic with various stand-by/operation time ratios) on carbon monoxide (CO) and nitrogen oxides (NO, NOx) concentration values in the flue gas was analyzed for coniferous wood pellet firing. Experiments were performed using a 20 kW water boiler equipped with an under-fed (retort) wood pellet furnace located in a full scale heat station simulating real-life conditions. Impact of oxygen concentration and temperature in the combustion chamber on the concentrations of carbon monoxide and nitrogen oxide have been examined. It was concluded that the commonly used periodic fuel supply does not necessarily cause an important increase of the concentrations of carbon monoxide compared to those in the continuous fuel feeding mode. Continuous fuel supply can even imply higher concentrations of carbon monoxide when fuel and air streams are not chosen properly.

Reducing Emissions from Combustion of Grape Residues in Mixtures with Herbaceous Biomass

“…This is explained by an increase in the volume of excess air, which decreased the flue gas temperature, (see Figure 3 ) and thus the carbon monoxide was not completely oxidized [ 58 ]. The general trends agree with the results of biomass combustion by Juszczak [ 37 ] or Malaťák et al [ 25 ].…”

“…Samples from red grape pomace were the closest to these values. Reducing such high average emission concentrations in combustion plant operation is often difficult [ 37 ]. In general, on an existing combustion plant it is possible to reduce emissions by regulating the input of air [ 56 ], or by choosing a more suitable fuel [ 57 ].…”

“…One approach to minimizing emissions is to increase system efficiency and reduce the number of burn cycles that include start-up and shut-down periods where the emissions are higher [ 36 ]. A discontinuous fuel supply mainly leads to increased concentrations of carbon monoxide and nitrogen oxides compared to a continuous fuel supply [ 37 ]. Maximum CO 2 concentrations are reached at low, excess air co-efficients [ 36 ] together with the highest combustion temperature [ 38 ].…”

Concentration of Nitrogen Oxides when Burning Wood Pellets of Various Origins

“…An inherent element of these processes, both in industrial and local power section, is the emission of harmful substances during combustion, which are closely related to the technical parameters of boilers [Boman et al . The main impact on the efficiency of the combustion process results from the method of supplying fuel to the furnace [Juszczak 2016]. On the other hand, limiting the emission of toxic compounds is associated with a proper organization of the combustion process, which directly affects the characteristics of the emitted harmful substances related to the air-fuel equivalence ratio (λ) .…”

Evaluation of Co and Nox Emissions in Real-Life Operating Conditions of Herbaceous Biomass Briquettes Combustion

“…Emissions production is influenced not only by the type of fuel (Zosima and Ochsenkiihn-Petropoulou, 2015) but also by the type of combustion technology (Malaťák and Passian, 2011;Win et al, 2012). Above all, discontinuous fuel supply leads to increased concentrations of carbon monoxide and nitrogen oxides in comparison to continuous fuel supply (Juszczak, 2016).…”