7. IMPROVISATIONS OF RANKINE CYALE
1. Reheating
• Flue gas reheating
• Live steam reheating
• Combined flue gas and live steam reheating
2. Regeneration
• Ideal
• Single Stage
• Two Stage
3. Combined Reheating and Regeneration
38. COAL CLEANING EQUIPMENTS
1. Removal of dirt – Primary screen to size less than 8cm
2. Coal drying - Moisture Less than 10%,heatby steam
3. Coal sizing – Uniformity of coal size is essential
4. Sulphur removal – More than 2.5% sulphur is restricted due to
fouling and corrosion
5. Washing
(i) Water Jigs
(ii) Concentrating table
(iii) hydro cyclone
(iv) Heavy medium
77. Surface Condenser
1. Down flow type. Steam enters at
the top and flows downward. The
water flowing through the tubes in
one direction lower half comes out
in the opposite direction in the upper
half.
78. Central flow condenser. In this condenser the steam passages are all around
the periphery of the shell. Air is pumped away from the centre of the
condenser. The condensate moves radially towards the centre of tube nest.
Some of the exhaust steams while moving towards the centre meets the under
cooled condensate and pre-heats it thus reducing under cooling.
Evaporation condenser. In this condenser steam to be condensed is passed
through a series of tubes and the cooling waterfalls over these tubes in the form
of spray. A steam of air flows over the tubes to increase evaporation of cooling
water, which further increases the condensation of steam.
79. Jet Condenser
In jet condensers the exhaust steam and cooling water come in direct
contact with each other. The temperature of cooling water and the condensate
is same when leaving the condensers.