Electrostatic Precipitator Performance and Trace Element Emissions from Two Kraft Recovery Boilers

Abstract

Fine particle emissions from combustion sources have gained attention recently due to their adverse effects on human health. The emission depends on the combustion process, fuel, and particulate removal technology. Particle concentrations at Kraft recovery boiler exits are very high, and the boilers are typically equipped with electrostatic precipitators (ESP). However, little data are available on the ESP performance in recovery boilers. Particle concentrations and size distributions were determined at two modern, operating recovery boilers. In addition, we determined the fractional collection efficiency of the ESPs by simultaneous measurements at the ESP inlet and outlet and the particulate emissions of trace metals. The particle mass concentration atthe ESP inlet was 11-24 g/Nm3 at the two boilers. Particle emissions were 30-40 mg/ Nm3 at boiler A and 12-15 mg/Nm3 at boiler B. The particle size distributions had a major particle mode at around 1 microm. These fume particles contained most of the particle mass. The main components in the particles were sodium and sulfate with minor amounts of chloride, potassium, and presumably some carbonate. The ESP collection efficiency was 99.6-99.8% at boiler A and 99.9% at boiler B. The particle penetration through the ESP was below 0.6% in the entire fume particle size range of 0.3-3 microm. Trace element emissions from both boilers were well below the limit values set by EU directive for waste incineration.

Separation, treatment and utilization of inorganic residues of chemical pulp mills

“…The typical concentration range of collected fine (0.2e1 mm) dust is 5e15 g m À3 of flue gas (Hupa, 1993), and the separation efficiency is often over 99% (Lind et al, 2006). Electrostatically separated fly ash is typically mixed with black liquor and re-burned in a recovery boiler.…”

Causes of Haze in the Columbia River Gorge

“…Emissions from Kraft recovery boilers have been shown to consist largely of sodium and sulfate particles (i.e., Na 2 SO 4 ) with lesser but significant amounts of chlorine and potassium. 19,20 Vanadium and nickel, which are associated with oil combustion, 15 are …”

Expansion of a size disaggregation profile library for particulate matter emissions processing from three generic profiles to 36 source-type-specific profiles

“…Lastly, an average fractional-penetration profile for baghouse filters based on all three studies was calculated. A set of size-dependent correction factors for another control device, the electrostatic precipitator (ESP), was also determined from penetration fraction data published in Lind et al (2006). These two sets of size-bin-specific correction factors were then applied as follows to the final calculated size-bin weight factors for the uncontrolled profiles to obtain the final corrected weight factor set.…”

“…It is important to note that not all facilities belonging to these five source types necessarily use baghouse filters as their control device, but this particular control device was assumed for all such facilities due to the availability of size-resolved control efficiency measurements. In the studies by Lind et al (2006) and Mikkanen (2000), however, an electrostatic precipitator (ESP) was specified as the control device for PM emissions from a kraft recovery furnace. The authors of the Lind et al (2006) study only included the size distribution plot for the sample obtained before the ESP, but they also published penetration fraction data for the ESP by measuring samples before and after treatment.…”