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31 Cards in this Set
- Front
- Back
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When referring to "Direction of axis" of a boiler what is meant? |
Horizontal Vertical - Watertubes industry standard |
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What is meant by "according to use" when classifying a boiler? |
Portable Stationary Marine |
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What are the location of furnaces in a boiler? |
Internally fired Externally fired |
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When classifying a boiler by pressure. What are they? |
High pressure Low pressure Special purpose |
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What types of Vertical fire tube boilers are their? |
Dry top - exposed tube took heat on fire up, no steam to protect, steam being exposed directly to combustion would superheat 10 to 15 degrees
Wet top - submerged tube type |
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How were HRTs supported? What are determined what methods are used? |
Lugs and rollers & overhead suspension • 2 lugs when diameter is up to 54" • 4 lugs over 54" to 72" • overhead suspension required when over 72" |
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Why are HRTs pitched? How much are they sloped? |
To be blown down • pitched to rear for coal • pitched to front to burn oil • slope is 1 to 3 inches |
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What is meant by "Boiler bag"? |
Impurities on shell would cause a loss in heat transfer causing that spot to overheat. Overheated spot when stressed by pressure would cause a bulge. |
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Scotch type boiler |
• internally fired - creating surface area Two Types • dry back • wet back - increased surface area |
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What is the purpose of a "Scrubber"? |
Prevents high velocity steam with water droplets from priming and carryover |
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What is the purpose of a "Scrubber"? |
Prevents high velocity steam with water droplets from priming and carryover |
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Advantages of "superheated steam" |
• more BTUs/ lb • can be transmitted further.. Does more work without giving up energy • Turbines need superheated steam so blades arnt corroded by moisture • Takes 1/2 a BTU to raise 1 lb of water 1 degree fahrenheit |
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HRT state exam ?'s |
Back (Definition) |
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Purpose of a "dry pipe" |
Seperate a moisture from steam by changing direction of steam causing water droplets to fall out |
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Scotch type boiler state exam ?'s |
Back (Definition) |
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Package type boilers Advantages and disadvantages |
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How to draw 4 pass Scotch |
Back (Definition) |
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What types of Water tube boilers are their? |
Back (Definition) |
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What types of Water tube boilers are their? |
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Tell me about Cyclone separators |
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Watertube boilers Classification & advantages |
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Super critical boilers |
• 3206.2 psi @ 705.4 deg. F • @ 3206.2 psi water becomes steam without latent heat • requires extremely pure water • everything happens fast |
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Superheaters & Reheaters |
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Methods of steam temp. control |
Back (Definition) |
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Why do you use radiant and convection superheated together? |
So you have a flatter temp profile |
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Explain what happens when steam goes through PRV |
• constant Enthalpy • your temp decreases • your pressure decreases • you GAIN entropy
"Entropy" - heat available for work
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What does an economizer do? |
Preheats feedwater by reducing exiting flue gas temperature
Every 40 degree rise in FW temp overall plant efficiency is gained by about 1% |
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What does an air pre heater do? |
Recovers heat from exiting flue gas and transfers it to the combustion air
• plant efficiency rises 1% for every 100 degrees rise in combustion air |
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Name two types of air preheaters |
Back (Definition) |
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What does an air pre heater do? |
Recovers heat from exiting flue gas and transfers it to the combustion air
• plant efficiency rises 1% for every 100 degrees rise in combustion air |
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Name two types of air preheaters |
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