Unit 11: Boiler Designs Flashcards
Mud Drum
Allows sediment to settle in the bottom drum of a watertube boiler
Steam Drum
Top drum in a watertube boiler that allow steam to rise up through risers from the mud drum
Fireside
Which ever side the heat or hot combustion gas is on a pipe inside a boiler.
Waterside
The side of the pipe the water is on or in.
Power Boiler Design Outlines
Steam Pressure is above 100 kPa / 15psig
Hot Water Pressure above 1.1 MPa
Temperature is above 120C
ASME I
Heating Boiler Design Specifications
Steam Pressure is less than or equal to 100 kPa
Hot Water Pressure is less than or equal to 1.1 MPa
Temperature is is less then or equal to 120C
ASME I
Shell
Main pressure vessel of a firetube boiler
Drum
Main pressure vessel of a watertube boiler
Heads
Is what encloses Shells or Drums at each end
Tubesheet
Is a head of a firetube boiler
Stays
are used for internal support of firetube boilers
radiation is the transfer of heat through?
electromagnetic radiation
Radiation is the transfer of heat energy through space by electromagnetic radiation. Most of the electromagnetic radiation that comes to the earth from the sun is invisible. Only a small portion comes as visible light.
Lowest Permisable Water Level in Firetube Boilers?
25 mm above the heating element/fireside tube.
What is saturation temperature?
Saturation temperature means boiling point. The saturation temperature is the temperature for a corresponding saturation pressure at which a liquid boils into its vapor phase.
When is forced circulation required in watertube boilers?
When pressures are higher around 12.5 MPa
Continuous Blowdown Pipe
A pipe found just below the water line in a boiler and removes dissolved solids from the water. This prevents foaming which can cause water to leave with the steam.
Foaming
When dissolved solids build up in boiler water it can cause foaming which causes moisture to attach itself to steam exiting.
Baffles
Separates steam from the water in watertube boilers. The steam continues up risers and the water is sent back downcomers to the mud drum
Scrubbers or Chevron Dryers
are used as steam separators. They move metal plates in different directions quickly stopping the water but steam can move quick enough to move around the plates.
Waterwalls
Water piping that surrounds a boiler to increase refractory and efficiency
Blowoff Valve
manually operated valve connected to the boiler for the intermittent discharge of boiler sediment.
Blowoff Vessel
A pressure vessel that contains blowoff discharge until it is cool enough to enter back into the municipal sewer systems.
ID fan
An induced fan that exhausts hot gases from the furnace after combustion. This is the opposite of a forced draft fan which sucks air into the furnace.
A-type Watertube boiler
Has two mud drums
D-Type Boiler
1 steam drum and 1 mud drum with bent tubes on one side of the boiler forming a d shape.
O-Type Watertube Boiler
Compact and water-cooled and doesn’t use much radiant heat
Steam Generating Unit
A large watertube boiler that has been field erected. These super large boilers generally have extra auxiliary equipment that is not present on smaller boilers. Such as superheaters, reheaters, economizers, and air heaters.
Superheater
Are tubes that surround the furnace outlet to remove moisture from steam and further increase their sensible temperature.
Reheater
Increases the temperature of steam leaving a turbine which further reduces the chance of condinsation.
Economizer
Transfer waste heat from flue gas to feedwater. which reduces thermal shock of cold water entering boiler and increase efficiency of steam production.
Flue Gas
Hot combustion gas that leaves the furnace is called flue gas
One Pass fire tube boilers?
Vertical Firetube heating boilers
