Energy and exergy analysis of the silicon production process

Takla, Marit; Kamfjord, Nils-Eivind; Tveit, Halvard; Kjelstrup, Signe

doi:10.1016/j.energy.2013.04.051

Cited by 70 publications

(46 citation statements)

References 7 publications

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“…Figure 3 shows the operation standards and the impact of silicon yield(s) and energy recovery on the exergetic efficiency for the silicon process. The absolute maximum theoretical efficiency is about 75%-ie the silicon process has 25% exergy destruction (7). The industrial efficiency is much lower.…”

Section: Productionmentioning

confidence: 99%

Silicon and Silicon Alloys, Production and Uses

Dosaj

Tveit

2016

Kirk-Othmer Encyclopedia of Chemical Technology

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Silicon, a low density chemical element having nonmetallic characteristics, is the second most abundant element in the lithosphere (after oxygen). Silicon occurs naturally in the form of oxides and silicates and constitutes over 25% of the earth's crust. The production of silicon from silica and silicon refining technology are discussed in this article as well as the primary uses in the chemical, aluminum, solar electronics, and ceramic industries are also discussed. Silicon is the chemical precursor of silicones, a versatile, fast‐growing market, and of advanced ceramics such as silicon nitride. It forms alloys with a large number of metallic elements; many of these alloys are of importance to the production and refining of irons and steels. The most prevalent are the ferrosilicons, production of which is discussed. Silicon is also one of the leading elements used for making photovoltaic cells for conversion of sun light to electricity and for manufacturing semiconductors in the electronics industry.

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Section: Productionmentioning

confidence: 99%

Silicon and Silicon Alloys, Production and Uses

Dosaj

Tveit

2016

Kirk-Othmer Encyclopedia of Chemical Technology

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“…[12] and [13] to give an equation with a spatial derivative of U g ðC CO þ C SiO Þ and a time derivative of a function of temperature and the solid and liquid concentrations. This tells us that the no voids condition [16] has characteristics with direction k c ¼ 1, corresponding to t ¼ constant. Hence, we need a boundary condition for U g ðz; tÞ.…”

Section: J Boundary and Initial Conditionsmentioning

confidence: 99%

“…Multiplying the no voids condition [16] by P TOT =RT then taking a time derivative, we can substitute in Eqs. [12] and [13] to give an equation with a spatial derivative of U g ðC CO þ C SiO Þ and a time derivative of a function of temperature and the solid and liquid concentrations.…”

Section: J Boundary and Initial Conditionsmentioning

confidence: 99%

“…Thus, only initial conditions are needed for the gas concentrations. These must satisfy the no voids condition [16], along with the initial conditions of the solid and liquid concentrations and the temperature. We are free to impose the initial partial pressure of SiO, P SiO , which we take to be 1 2 .…”

Section: J Boundary and Initial Conditionsmentioning

confidence: 99%

“…[7] through [13] with reaction rates described in Section II-H, in addition to the no voids condition [16], the temperature Eq. [17], and the constant sum of partial pressures [14].…”

Section: J Boundary and Initial Conditionsmentioning

confidence: 99%

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A Heat and Mass Transfer Model of a Silicon Pilot Furnace

Sloman

Please

Gorder

et al. 2017

Metall Mater Trans B

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The most common technological route for metallurgical silicon production is to feed quartz and a carbon source (e.g., coal, coke, or charcoal) into submerged-arc furnaces, which use electrodes as electrical conductors. We develop a mathematical model of a silicon furnace. A continuum approach is taken, and we derive from first principles the equations governing the time evolution of chemical concentrations, gas partial pressures, velocity, and temperature within a one-dimensional vertical section of a furnace. Numerical simulations are obtained for this model and are shown to compare favorably with experimental results obtained using silicon pilot furnaces. A rising interface is shown to exist at the base of the charge, with motion caused by the heating of the pilot furnace. We find that more reactive carbon reduces the silicon monoxide losses, while reducing the carbon content in the raw material mixture causes greater solid and liquid material to build-up in the charge region, indicative of crust formation (which can be detrimental to the silicon production process). We also comment on how the various findings could be relevant for industrial operations.

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Exergy-based performance indicators for industrial practice

2018

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Summary Key performance indicators (KPIs) are powerful tools that industries can use not only to monitor their activities but also to highlight their unexploited potential. Energy‐based KPIs are nowadays mostly used to evaluate industrial process performances. However, these indicators might present some limitations and might give misleading results in some circumstances. An example is represented by industrial processes that make use of different energy forms (eg, electricity and heat) and of different material inputs, and that are therefore difficult to compare in terms of energy. A further example can be found in the Carnot engine that, despite being ideal, can have quite low energy efficiency (eg, the energy efficiency of a Carnot engine working between 700 and 300 K is 57%), suggesting that its performance can be improved. The use of exergy‐based KPIs allows us to overcome many of the limitations of energy‐based indicators. The exergy efficiency of Carnot engines is 100%, clearly indicating that the system cannot be further improved. Moreover, the use of specific exergy consumption instead of specific energy consumption to monitor the performance of a process allows one to take into account possible differences in quality of material and energy streams. In the present work, exergy‐based KPIs for industrial use are reviewed. The paper outlines advantages and limitations of the reviewed indicators, with the scope of promoting their use in industry. A systematic use of exergy‐based KPIs not only gives a meaningful representation of process performances in terms of resource use but it can also direct efforts to improve the processes. To better understand their meaning under different circumstances, the revised indicators are applied to 3 industrial processes.

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Energy and exergy analysis of the silicon production process

Cited by 70 publications

References 7 publications

Silicon and Silicon Alloys, Production and Uses

Silicon and Silicon Alloys, Production and Uses

A Heat and Mass Transfer Model of a Silicon Pilot Furnace

Exergy-based performance indicators for industrial practice

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