Power Plant Engineering and thermodynamics Practice Flashcards

Comprehensive vocabulary flashcards covering fuel combustion, power plant variable load management, and the principles of thermodynamics as presented in Pipe Elements Sets 1, 2, and 3.

Higher Heating Value (HHV)

The heating value of a fuel that assumes the water formed during combustion is condensed to liquid.

Lower Heating Value (LHV)

The heating value that differs from HHV because it excludes the latent heat of water vapor.

Ultimate Analysis

A chemical analysis of coal performed to determine its elemental composition, specifically carbon, hydrogen, nitrogen, sulfur, and oxygen.

Proximate Analysis

A measurement of coal to determine its moisture, volatile matter, fixed carbon, and ash content.

Stoichiometric Air-Fuel Ratio

The theoretical air-to-fuel ratio where there is no excess or deficiency of air for combustion.

Flash Point

The minimum temperature at which a liquid fuel gives off enough vapors to form an ignitable mixture with air.

Fire Point

The temperature, higher than the flash point, at which a liquid fuel will continue to burn after ignition.

Cetane Number

A measure of the ignition quality of diesel fuel; typical values for diesel range from $40$ to $55$.

Octane Number

A measure of a fuel's tendency to knock in spark ignition engines.

Fixed Carbon

The carbon remaining in a solid fuel after the volatile matter has been driven off.

Bomb Calorimeter

An apparatus used specifically to determine the calorific value of fuels.

Producer Gas

A fuel gas mixture consisting mainly of $CO$ and $H_2$.

Water-Gas

A fuel gas produced by blowing steam through hot coke, primarily composed of $CO$ and $H_2$.

Orsat Apparatus

An instrument used to measure flue-gas analysis, specifically the concentrations of $CO_2$, $O_2$, and $CO$.

Octane ($C_8H_{18}$)

A hydrocarbon represented by the chemical formula $C_8H_{18}$.

Saybolt Seconds

A unit of measurement typically used to express the viscosity of fuel oil.

ASTM D240

The standard test method for determining the heat of combustion of liquid hydrocarbons.

Wobbe Index

A parameter used to compare the interchangeability of gaseous fuels based on their calorific value and specific gravity.

Variable Load

The fluctuation in electrical demand on a power plant over a period of time.

Spinning Reserve

The backup generating capacity that is kept running and synchronized to the grid to handle sudden load increases.

Load Factor

The ratio of the average load to the maximum demand over a specified period.

Automatic Generation Control (AGC)

A system used in power grids to maintain system frequency and manage interchange schedules during variable load conditions.

Sliding Pressure Operation

A method of operating a boiler at variable pressure to minimize thermal stress during part-load operation.

Unit Commitment

The process of determining which generating units should be running to meet the forecasted electrical load efficiently.

Zeroth Law of Thermodynamics

The law that defines the concept of temperature and provides the basis for its measurement.

First Law of Thermodynamics

The law stating that energy cannot be created or destroyed, only transformed (Conservation of Energy).

Intensive Property

A property of a thermodynamic system that is independent of the mass of the system, such as temperature or pressure.

Specific Entropy

A measure of molecular disorder per unit mass, expressed in SI units as $J/kg\,K$ or $J\,kg^{-1}\,K^{-1}$.

Enthalpy ($h$)

A thermodynamic property defined by the relation $h = u + pv$, where $u$ is internal energy, $p$ is pressure, and $v$ is specific volume.

Absolute Zero

The lowest possible temperature, equivalent to $-273.15\,^{\circ}C$ on the Celsius scale.

Coefficient of Performance (COP)

For a refrigerator, it is defined as the ratio of the heat absorbed to the work input.

Specific Heat Ratio ($\gamma$)

The ratio of the specific heat at constant pressure to the specific heat at constant volume, calculated as $\frac{C_p}{C_v}$.

Exergy

The portion of energy that can be converted into useful work as a system reaches equilibrium with its surroundings.

Dryness Fraction

The ratio of the mass of vapor to the total mass in a mixture of liquid and vapor.

Mollier Diagram

A thermodynamic chart that plots enthalpy ($h$) against entropy ($s$).

Critical Point

The specific pressure and temperature at which the liquid and vapor phases of a substance become indistinguishable.

Joule-Thomson Expansion

A process used to liquefy gases by expansion at constant enthalpy.