1.  create vacuum in furnace

2.  create vacuum at turbine exhaust

4.  dose chemicals in feed water

1.  babcock and wilcox

3.  lancashire

4.  cochran

1.  former is fire tube type and latter is water tube type boiler

2.  former is water tube type and latter is fire tube type

4.  All the above

1.  heating takes place at bottom and the water supplied at bottom gets converted into the mixture of standard bubbles and hot water which rise to drum

3.  feed pump is employed to supplement natural circulation in water wall type furnace

4.  water is converted into steam in one pass without any re-circulation

5.  

1.  former generates steam at high pressure

2.  former occupies less space for same power

3.  rate of steam flow is more in former case

1.  one

2.  two

3.  one steam drum and one water drum

1.  avoid excessive build-up of pressure

2.  avoid explosion

4.  control steam dome

1.  in the drum

2.  in the fire tubes

3.  above steam dome

2.  copper

3.  aluminum

4.  nickel

1.  heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum

2.  water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam

4.   water is converted into steam in one pass without any re-circulation