Pilot Scale Measurements of NO Emissions from the Silicon Process

Kamfjord, Nils Eivind; Tveit, Halvard; Solheim, Ingeborg

doi:10.1002/9781118364987.ch50

Cited by 4 publications

(3 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…32 Efforts to understand the NO X formation have shown that furnace design and furnace operating procedures, such as stoking and charging, heavily influence NO X emissions. [33][34][35][36][37][38][39] Reported NO X emission values vary greatly, with typical values ranging from 500 to 1500 ton per site and year. 12 The NO X production is inversely proportional to the silicon yield (low Si yield, high SiO losses), at least up to a certain level of silica fume formation.…”

Section: Nitrogen Oxides Noxmentioning

confidence: 99%

Airborne Emissions from Si/FeSi Production

Kero

Grådahl

Tranell

2016

JOM

View full text Add to dashboard Cite

The management of airborne emissions from silicon and ferrosilicon production is, in many ways, similar to the management of airborne emissions from other metallurgical industries, but certain challenges are highly branch-specific, for example the dust types generated and the management of NO X emissions by furnace design and operation. A major difficulty in the mission to reduce emissions is that information about emission types and sources as well as abatement and measurement methods is often scarce, incomplete and scattered. The sheer diversity and complexity of the subject presents a hurdle, especially for new professionals in the field. This article focuses on the airborne emissions from Si and FeSi production, including greenhouse gases, nitrogen oxides, airborne particulate matter also known as dust, polyaromatic hydrocarbons and heavy metals. The aim is to summarize current knowledge in a state-of-the-art overview intended to introduce fresh industry engineers and academic researchers to the technological aspects relevant to the reduction of airborne emissions.

show abstract

Section: Nitrogen Oxides Noxmentioning

confidence: 99%

Airborne Emissions from Si/FeSi Production

Kero

Grådahl

Tranell

2016

JOM

View full text Add to dashboard Cite

show abstract

“…Kamfjord investigated silica fume formation from SiO combustion with focus on how SiO combustion can be a source for thermal NO X generation in the process. He showed that SiO combustion is a major source of heat which causes thermal NO X generation through the Zeldovich mechanism …”

Section: Introductionmentioning

confidence: 99%

Silica Fume Formation in Different Gas Atmospheres

Andersen

Einarsrud

Rasouli

et al. 2023

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Silica fume is an important byproduct from the silicon production process, with mainly concrete and refractory applications. In this work, the effect of different combustion gas atmospheres on the properties of silica fume has been investigated through small-scale experiments and a pilot-scale experiment. In the small-scale experiments, SiO gas was formed and reacted with four mixtures of nitrogen fixed at 79 vol %, oxygen, carbon dioxide, and carbon monoxide. No significant difference between the particulate matter (PM) formed was found when replacing O 2 with CO 2 using a holding temperature of 1700 °C, when measuring the specific surface area (SSA), particle size distribution, or carbon content. PM formed at a holding temperature of 1650 °C was found to have a significantly higher SSA of 32.9 m 2 /g compared to the SSA of 22.3 m 2 /g formed at 1700 °C with the same gas mixtures. Condensation products were only found when replacing O 2 with CO, where brown PM was formed through SiO reacting with SiO 2 , SiC, and Si. Using a pilot-scale setup, the combustion gas for the silicon process was altered by recirculating different ratios of flue gas back to the furnace hood. Silica fume samples were collected during several tapping cycles with varying flue gas recirculation (FGR) rates. The SSA was measured for the sampled PM and correlated to a selection of operational parameters. A significant negative correlation was found between the SSA of PM and the concentration of H 2 O and SO 2 in the off-gas, while a significant positive correlation was found between the SSA and the temperature of the off-gas, the concentration of dust in the off-gas, and the NO X generation during the process. These results indicate that the temperature and SiO concentration during combustion are more important than the CO 2 (or O 2 ) concentration in the combustion atmosphere. Using FGR to increase the CO 2 concentration in the off-gas should not change the silica fume particle size, if the H 2 O content is controlled.

show abstract

“…[23][24][25][26] However, the chemical composition of the condensed particulate matter (CPM) and the variations of the CPM's originating from various process steps in the silicon plant remains unknown. This in turn constitutes a problem with respect to the correct assessment of environmental impact and working conditions, not only for the industry itself but also for the regulatory authorities.…”

Section: Introductionmentioning

confidence: 99%