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

Proportional-Integral-Derivative (PID): a type of feedback controller whose output, a control variable (CV), is
generally based on the error (e) between some user-defined set point (SP) and some measured process variable
(PV). Each element on the PID controller refers to a particular action taken on the error.
pull rate: The quantity of glass delivered by a glass furnace during a designated period of time (usually 24 h).
recuperative furnace: A melting furnace having a recuperator. See also recuperator.
recuperator: A continuous heat exchanger in which heat from exhaust gases from the glass furnace is conducted
through flue walls or a system of ducts to incoming air.
redox: A term for oxidation-reduction reactions observed in chemical systems. The term “redox equilibria” is used
to refer to the balance between reduction and oxidation in the glass furnace, which is important for controlling the
fining process and the final glass color.
refining: The process in which bubbles and undissolved gases and solids are removed from the molten glass. See
also bubble.
refractories: Ceramic materials that have high melting points and withstand high temperatures. They typically are
hard and are resistant to abrasion, corrosion, and rapid thermal fluctuations. In glass manufacturing, they are used to
line and insulate the glass furnace tank and other high-temperature areas such as the checker system.
regenerator: A cyclic heat interchanger that alternately receives heat from gaseous combustion products from the
glass furnace and transfers that heat to air or gas before combustion. A glass furnace that incorporates regenerators
is called a regenerative furnace.
required rate of return: Return required by investors before they will commit money to an investment at a given
level of risk. Unless the expected return exceeds the required return, an investment is economically unattractive. See
also hurdle rate.
residual income: A divisional profitability indicator that represents the “profit” remaining after the suppliers of all
resources required to generate revenues have been fairly compensated, including the supplier of the capital, the
parent corporation. It is determined by assessing a capital charge, which is subtracted from division income, to
arrive at division residual income.
residual value: The amount a company expects to be able to sell a fixed asset for at the end of its useful life.
return on sales: Net pre-tax profits as a percentage of net sales, a useful measure of overall operational efficiency
when compared with prior periods or with other companies in the same line of business.
return on invested capital: Amount, expressed as a percentage, earned on a company’s total capital of its common
and preferred stock equity plus long-term funded debt. Calculated by dividing total capital into earnings before
interest, taxes, and dividends.
roadmap: A detailed plan that seeks to provide guidance and clarity on specific issues to an organization or
industry group and ensures that these issues are executed in an efficient and effective manner.
scrubber: Emission control device that assists in the removal of solid particles from combustion gases generated
from a glass furnace. Scrubbers (wet or dry) are typically part of an overall emission control system.
skull melting: a containerless method for melting and crystallizing materials at very high temperatures (>3000˚C)
seed: A small (fraction of a millimeter diameter) gaseous inclusion (bubble) in glass. See also bubble.
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