Power Plant Engineering (PPE) MCQs | Page - 2

 low pressure system moves the ash mixed in water at a distance of 3 to 5 m/s in a sloped pump made of reinforced constituents and this movement is continuous. so, it has the ability to carry the ash for such long distance. there is no requirement any auxiliary source to move the ash mixed with water.

 the capacity of low pressure hydraulic ash handling system is 50tonnes/hour at a speed of 3m/s. since the ash produced is mixed in water and dumped, the water has the ability to dissolve and intake more amount of ash. and this mixture is spread throughout the sump.

 the term ‘draught’ is used to define the static pressure in the furnace, in the various ducts and the stack.

 the draught produced is given by Δp = gh(ρa-ρg).

 the three types of mechanical drafts are balanced, induced and forced drafts.

 excess amount of air leads to significant losses in energy due to heat loss through flue gases.

 all these reasons lead to clinkering.

 a positive pressure exists in the furnace employing forced draught.

 axial fans have the highest cost.

 except ‘electronically adjustable turbine drive’, all other are a type of drive in variable speed control.