38 terms

Chapter 9 - Introduction to Process Technology Equipment & Systems

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Bellows trap
a thermostatic steam trap that operates by opening or closing a bellows as the temperature changes; this movement opens and closes a valve.
Boiler load
plant demand for steam.
Burner
Used to evenly distribute air and fuel vapors over an ignition source and into a boiler firebox.
Damper
a device used to regulate airflow.
Desuperheating
a process applied to remove heat from superheated steam.
Downcomers
the inlet tubes from the upper to lower drum of a water-tube boiler; these tubes contain hot water.
Economizer
a section of a fired boiler used to heat feedwater before it enters the steam drums.
Fire-tube boiler
a type of boiler that passes hot gases through tubes to heat and vaporize water.
Flame impingement
frequent or sustained contact between flames and tubes in fire-tube boilers and furnaces.
Float steam tap
a steam tap that operates with a float that opens a valve as the condensate level rises.
Inverted bucket steam trap
a mechanical steam trap that operates with an inverted bucket inside a casing; effective on condensate and noncondensing vapors.
Mud drum
the lower drum of a water-fuel gas burner.
Steam-generating drum
a large upper drum partially filled with feedwater. This drum is the central component of a boiler. It is connected to the lower mud drum by the downcomer and riser tubes and receives steam from the steam-generating tubes.
Steam trap
a device used to separate condensate from steam and return it to the boiler to be converted to steam.
Superheated steam
steam that is heated to a higher temperature.
Thermostatic steam tap
a type of steam trap that is controlled b temperature changes.
Water hammer
a condition in a boiler in which slugs of condensate (water) flowing with steam damage equipment.
Water-tube boiler
a type of boiler that passes water-filled tubes through a heated firebox.
1. What is the name of the section in a water-tube boiler that pre-heats the water?
The economizer section
2. What is a spud?
Components of a natural gas burner that distributes fuel gas.
3. Contrast a water-tube boiler and a fire-tube boiler?
A water tube boiler has water in the tubes and fire outside heating the water. A fire tube boiler has fire or heat inside the tube and water outside.
4. Contrast a downcomer tube with a generating, or riser, tube.
A downcomer tube allows cooler water to flow downward and enter the mud drum so that it can be reheated into steam by entering the riser. The riser will then allow water to rise and be heated until it becomes steam. Together they create a sort of water/steam recycling system.
5. Identify the key components of a water-tube boiler, and describe the water circulation in the boiler.
The main components of a water tube boiler are the furnace, the tubes, the drums, the gas/oil burner, and the economizer. Cool water comes in through the inlet and then flows down the downcomer to then be heat in the pipes. As it heats the warmer water then begins to rise up the risers until it boils and becomes steam. Steam escapes through the top while cooler water then recirculates through the process again.
6. Contrast superheated steam, desuperheated steam, and saturated steam.
Superheated steam is simply steam heated to a higher temperature. Superheated steam which has been cooled is called desuperheated steam. Saturated steam is merely steam which still has moisture content.
7. List five operations in which steam is used.
Heating/Sterilization
Propulsion/Drive
Cleaning
Moisturization
Humidification
8. List six types of tubes found in a water-tube boiler.
water in, downcomer, riser, steam generating, water make up, superheater tubes
9. Contrast the upper and lower drum in a water-tube boiler.
Water in the upper drum is usually high temp and either is just about to turn to steam or circulate back through the downcomer. Water in the lower mud drum is cooler and travels up through the risers as it heats to become steam.
10. List the key components of a natural gas burner.
Dampers, Air ducts, spuds, and an igniter.
11. What are the seven major things an operator does when starting up a boiler?
1. Fill the steam drum with water to a normal level.
2. Start the fan.
3. Purge the furnace.
4. Check the furnace for % of flammables.
5. Light the burners.
6. Bring the boiler up to pressure.
7. Place the boiler online.
12. List three operating problems found in a boiler.
Tube rupture, soot build up, and loss of water flow.
13. What is the purpose of a steam trap?
Steam traps are devices which are used to remove condensate.
14. Name the two classes of steam traps.
Mechanical and Thermostatic
15. Name and describe two types of mechanical steam traps.
Inverted Bucket Steam trap and a Float Steam Trap
16. Name and describe a type of thermostatic steam trap.
Bellows Thermostatic steam Trap
17. What term is used for a condition in which slugs of water cause damage to equipment?
Water hammer
18. Describe hazards associated with boiler operation.
Burns, natural gas, leaks, instrument failure, confines spaces, opening and blinding, hazardous energy LOTOTO, routine work on equipment and facilities, lighting burners, exceeding boiler pressures, water treatment chemicals, explosion/fire
19. Define placed on the line.
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20. Define boiler load.
Boiler load is the term for a given plants demand for steam.