Fossil-Fueled Power Plants Practice Flashcards

Comprehensive practice flashcards covering the components, cycles, thermodynamics, and emission control technologies of fossil-fueled power plants based on the lecture transcript.

Thermal (Fuel) Efficiency

The ratio of electrical energy output to fossil fuel energy input, often defined equivalently as the heat rate.

Rankine Cycle

A thermodynamics cycle used in most large-scale power plants where steam produced in a boiler drives a steam turbine to generate electricity.

Brayton Cycle

A thermodynamic cycle used by gas turbine plants where combustion products directly drive a gas turbine.

Fly Ash

Incombustible mineral matter, comprising more than 90% of total ash in pulverized coal plants, that is blown out of the boiler and captured in particle collectors.

Bottom Ash

Mineral matter that falls to the bottom of the boiler, comprising about 10% of total ash.

Slag

Deposited ash on water pipes lining the boiler that hinders heat transfer and must be removed periodically.

Economizer

A boiler section where feedwater is heated from approximately $230-260\,^{\circ}\text{C}$ to $315\,^{\circ}\text{C}$ before entering the steam drum.

Steam Drum

A large vessel mounted on top of a boiler where liquid water is separated from steam, typically by gravity.

Superheater

A section of the boiler that raises steam temperature to $565\,^{\circ}\text{C}$ at a pressure of $24\,\text{MPa}$ to drive high-pressure turbines.

Reheater

A boiler section that raises the temperature of exhaust steam from high-pressure turbines back to about $500\,^{\circ}\text{C}$ to drive low-pressure turbines.

Impulse Turbine

A turbine where a jet of steam impinges on symmetrical blades, often accelerated to supersonic velocities by a deLaval nozzle.

Reaction Turbine

A turbine where steam pressure drops across both fixed (stator) and moving (rotor) blades shaped as converging nozzles.

Condensation Shock

An irreversible process caused by supersaturation in reaction turbines when steam suddenly reverts to thermodynamic equilibrium and releases latent heat.

Electrostatic Precipitator (ESP)

An emission control device that charges fly ash particles negatively via a corona discharge and attracts them to grounded plates.

Deutsch Equation

The formula $\eta = 1 - \exp(-wA/Q)$, used to calculate the collection efficiency of an electrostatic precipitator.

Baghouse

A fabric filter system that uses long cylindrical tubes to remove particles from flue gas, similar to a domestic vacuum cleaner.

Coal Washing

A pre-combustion process at the mine mouth that removes mineral matter and pyritic sulfur by floating crushed coal in water.

Claus Process

A catalytic reduction-oxidation process used in refineries to remove sulfur from crude oil by converting sulfur compounds into elemental sulfur.

Fluidized Bed Combustion (FBC)

Burning coal embedded in a granular material like limestone riding on a stream of air, which captures sulfur during combustion.

Wet Scrubber

A flue gas desulfurization device that treats flue gas with an aqueous slurry of limestone or calcined lime to remove $SO_2$.

Fuel NOx

Nitrogen oxides formed during combustion from the organic nitrogen inherent in the molecular structure of coal and oil.

Thermal NOx

Nitrogen oxides formed by the recombination of atmospheric nitrogen and oxygen at high flame temperatures.

Selective Catalytic Reduction (SCR)

A post-combustion process where ammonia or urea is injected into a catalytic reactor to reduce $NO$ to elemental nitrogen.

Combined Cycle (GTCC)

A power plant system using a topping cycle (gas turbine) and a bottoming cycle (steam turbine) to achieve thermal efficiencies of about 45%.

Integrated Gasification Combined Cycle (IGCC)

A plant that gasifies coal into synthesis gas (syngas) to fuel a gas turbine combined cycle system.

Cogeneration

The simultaneous production of electrical power and useful process or space heat from the same fuel source.

District Heating

A system where exhaust gas or warm water from a central power station is piped directly into buildings for space and water heating.