Glass Melting Technology: A Technical and Economic ... - OSTI

cost of capital: Rate of return that a business could earn if it chose another investment with equivalent risk, in other
words, the opportunity cost of the funds employed as a result of an investment. Cost of capital is also calculated
using a weighted average of the firm’s costs of debt and classes of equity.
cracker/gas reformer equipment: Equipment used to reduce NOx emissions in the process of natural gas firing in
a glass furnace. In this method, about a quarter of the furnace gas consumption is taken through a separate “cracker”
that produces soot particles. These soot particles are then reblended with the balance of gas, producing a soot-rich
gas mixture. The combustion of this soot-rich gas produces a flame with increased luminosity and lower peak flame
temperatures. See also NOx.
cross-fired regenerative furnace: A regenerative glass furnace with burners and regenerators located on each side.
Typically, a group of burners from one side fires across the width of the furnace while the burners on the opposite
side remain idle. After a predetermined amount of time the sequence alternates. See also regenerator.
crystalline silica: The scientific name for a group of minerals composed of silicon and oxygen (SiO2). The term
“crystalline” refers to the fact that the oxygen and silicon atoms are arranged in a three-dimensional repeating
pattern. Prolonged exposure to dust containing crystalline silica is a health hazard and could lead to silicosis, a
noncancerous lung disease.
cullet: Waste or broken glass suitable as an addition to the glass batch. It can be from the same glass plant (factory,
in-house, or domestic cullet) or from an outside source (foreign cullet).
depreciation (finance): Amortization of fixed assets, such as plant and equipment, so as to allocate the cost over
their depreciable life. Depreciation reduces taxable income, but does not reduce cash.
distributor: A channel or series of channels that guides molten glass from the melter via a submerged throat to the
forehearth(s). Distributor channels are designed much like forehearths in that they are divided into temperature
control zones with independent firing systems. See also throat and forehearth.
E-glass: Abbreviation for electrical-grade glass. This glass is an alumina-borosilicate glass and is commonly used to
make fibers that require low alkali content.
electric boosting: A supplementary method of adding heat to a glass melt in a gas- or oil-fired furnace by passing
an electrical current through the molten glass.
electrostatic precipitator: Emission control device used to remove solid particles from combustion gases generated
from a glass furnace by giving the particles an electric charge and attracting them to charged plates. Electrostatic
precipitators are typically part of an overall emission control system.
end port furnace: A glass melting furnace in which the ports for the introduction of fuel and air are located in the
end or back wall. Also called an end-fired furnace.
energy balance: The arithmetic balancing of energy inputs versus outputs for an object or processing system such
as glass melting.
enthalpy: The sum of the internal energy of a body and the product of its volume multiplied by the pressure exerted
on the body by its surroundings. Also known as sensible heat, total heat, and heat content. Enthalpy values are
helpful in understanding energy efficiencies of glass furnaces.
environmental credits: A system of tradable emissions credits, developed by EPA in the 1970s, to implement
federal air quality standards in a more flexible and less costly manner. This system is designed to limit emissions
using market-based incentives to promote cost-effectiveness. Under this system, companies facing high pollution-
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