Power Engineering Boiler Terminology and Concepts

Vocabulary practice flashcards covering boiler design classifications, components, operating principles, and ASME code standards from the lecture notes.

Explosion door

A pressure relief device on a boiler furnace that opens to relieve excessive pressure in the event of a combustion explosion.

Recuperative air heater

An air heater that continuously transfers heat from outgoing flue gas to incoming combustion air through a stationary heat-exchanging wall.

Beaded tube ends

The rounded, expanded ends of firetubes that secure the tubes to the tube sheet and protect the metal edges from burning in hot flue gas.

Corrugated furnace tubes

Furnace tubes constructed with ridge-and-groove patterns to increase structural strength against collapse and accommodate thermal expansion.

Flexible water tube boiler

A water tube boiler engineered with bent, sloped tubes designed to absorb thermal expansion and stress without causing leakages at joints.

MAWP

Maximum Allowable Working Pressure; the maximum gauge pressure permissible at the top of a completed boiler in its normal operating position.

Manhole and handhole openings

Access openings provided in drums, headers, and shells to allow inspection, cleaning, tube expansion, and internal maintenance.

SOx emissions reduction in FBC

The capture of sulfur dioxide achieved by introducing limestone or dolomite into the fluidized bed material during solid fuel combustion.

Service Rating

The designated pressure and temperature parameters assigned to a boiler or pressure vessel for safe operational limits.

ASME Section I

The code section of the ASME Boiler and Pressure Vessel Code governing Power Boilers, stamped with the letter 'S'.

ASME Section IV

The code section of the ASME Boiler and Pressure Vessel Code governing Heating Boilers, stamped with the letter 'H'.

'O' type configuration

A packaged water tube boiler layout featuring an upper steam drum positioned directly above a lower mud drum, flanked symmetrically by vertical tube banks.

'D' type configuration

A packaged water tube boiler layout featuring two drums offset on one side with generating tubes extending out and back to form a 'D' shape.

'A' type configuration

A packaged water tube boiler layout featuring two lower mud drums and one central upper steam drum forming an 'A' shape.

Extended combustion gas passes

Additional paths designed into a boiler to direct flue gases across heating surfaces multiple times to increase heat absorption.

Chevron dryer

A steam separating device utilizing closely spaced corrugated plates that force steam to make rapid direction changes, dropping entrained water droplets out of suspension.

Forced circulation

Water flow within a boiler created and maintained mechanically by pumps, essential at higher pressures where natural circulation density differences diminish.

Heating surface

The area of boiler metal that is exposed to combustion gases or radiant heat on one side and boiler water or steam on the other.

Fins on tubes

Extended metallic projections added to water tubes to increase total heat-absorbing surface area and maximize thermal transfer.

Scotch boiler

An internally fired firetube boiler originally developed for marine applications, featuring a large cylindrical furnace tube entirely surrounded by water and firetubes.

Natural circulation

The circulation of water in a boiler driven solely by density differences between hotter steam-water mixtures in risers and colder water in downcomers.

Flue gas

The gaseous products of combustion after leaving the furnace section and travelling through the heat exchange passes.

Radiant superheater

A superheater positioned directly in the furnace that absorbs heat via radiation, whose outlet steam temperature decreases as steam output increases.

Convection superheater

A superheater positioned in the flue gas stream that absorbs heat via convection, whose outlet steam temperature increases as steam output increases.

Lagging

The protective outer metal jacketing installed over thermal insulation surrounding a boiler or hot piping system.

Economizer

A flue gas heat exchanger used to preheat boiler feedwater before it enters the steam drum, enhancing total plant thermal efficiency.

Membrane tube wall

A gas-tight furnace wall structure composed of adjacent water wall tubes connected together by continuously welded steel strips or fins.

Superheater

A boiler heat exchanger that adds heat to saturated steam to raise its temperature above saturation temperature without increasing pressure.

Electrode boiler

An electric boiler where electric current passes directly through the conductive boiler water between immersed electrodes, generating heat resistively.

Immersion boiler

An electric boiler that uses submerged electrical resistance heating elements to directly heat surrounding water.

Castable refractory

A high-temperature resistant concrete-like material poured or troweled to construct furnace linings, arches, and combustion baffles.

Telltale

A small hole drilled into the outer end of a staybolt to provide visible leakage in the event that the staybolt cracks or breaks.

Internal feedwater pipe

A perforated pipe located inside the steam drum designed to distribute incoming feedwater uniformly across the length of the drum to prevent localized thermal shock.