3.1 Introduction

1 What is one advantage of an interruptible gas supply compared to a non-interruptible supply?
a) The gas is cheaper
b) The boiler efficiency is normally higher
c) The gas is cleaner
d) Easier to obtain
2 Which of the following is a harmful by – product of coal combustion?
a) H2SO4
b) O2
c) SO2
d) SO3
3 What type of coal is generally used in a power station?
a) Lignite
b) Brown lump coal
c) Peat
d) Pulverised fuel
4 Which one of the following is probably true of decentralised boiler plant?
a) Reduction in manual supervision possible
b) Safety and efficiency protocols more easily monitored
c) Reduction in overall steam main losses
d) More choices of fuel and tariffs
5 What is used in a power station to remove sulphurous material?
a) Filters
b) Chain grate stoker
c) Electro – static precipitator
d) Gas scrubber
6 What is the disadvantage of an interruptible gas supply arrangement?
a) Greater storage of gas is necessary
b) The gas costs more
c) Interruptions can occur at short notice
d) Have to use heavy fuel oil as a reserve