Power Plant Gyan

CIRCULATION SYSTEMS In power plant boiler is used as a steam generator. From boiler high pressure & high temperature steam is generated and used in steam turbine. In power plant boiler may be drum type or without drum. Drum type boilers are called as sub-critical boiler because its working pressure is bellow critical pressure while without drum type boiler is called once through boiler because its pressure is higher than critical pressure. In sub-critical units boiler drum  acts as reservoir for  water & saturated steam and also provides means and arrangements for separation and purification of steam.  The term circulation generally refers that "the movement of fluid from boiler  drum to the combustion zone (furnace water walls) and back to the drum". In boiler drum steam separator equipment are installed. Feed water is supplied to the drum via the economizer in heated condition. when feed water enters in to the boi...

REGENERATIVE FEED WATER HEATING SYSTEM In regenerative feed water system steam is bled from the turbine from various stages and is made to give up its latent or any super-heat to the condensate in a heat exchanger, this system is called regenerative system. What is Regenerative Feed Heating? A small portion of steam expanding through the turbine is bled off from different stages of turbine before reaching condenser and used to heat feed water in the feed water heaters. This is called regenerative feed heating system. Why Regenerative Feed water heating? Loss of work that could have been obtained by expanding the extracted steam in the turbine (because of if we expand more steam from the turbine then after doing work this steam condensed in the condenser due to which its losses latent heat after condensation). Reduction in the energy supplied in the boiler (reduction of coal required in boiler which release energy after burning) to raise the temperature and pressure of the...

HEAT RATE IMPROVEMENT Optimizing Combustion.  The boiler is often a good place to begin to look for heat rate improvements. The operating conditions controlled by adjusting fuel and air flow rates among burners adjusting mixing patterns of coal and combustion air and adjusting economizer O2 level.  Changes to these parameters affect quantities such as combustion efficiency, steam temperatures, slagging and fouling patterns and Furnace heat absorption, which in many boilers have significant effects on unit heat rate.  Soot blowing Optimization.  Slagging and fouling deposits from coal ash accumulation on heat exchanger tubes affect boiler heat absorption patterns, steam temperatures and unit heat rate.  Soot blowing optimization is used to identify soot blowing strategies which prevent uncontrolled buildup of slag and soot deposits and minimize heat rate.   Soot blowing projects indicate potential heat rate improvements in the...

In the furnace, chemical energy of fuel is converted into the of combustion products as pulverised fuel is burned in suspension in the furnace space. Combustion products give up part of their heat by radiation to water walls. Thus they leave the furnace at a safe temperature, which will not cause clinkering of the subsequent convective heating surface.  Factors important for combustion = 3 T :  1) TIME = Residence time of fuel 2) TEMPERATURE = Furnace gas temp. (Must be > fuel ignition temp.)  3) TURBULENCE  1) => Furnace volume is large enough to give the mix. time to complete combustion. (Height of boiler is governed by the residence time of fuel) . 2) => Fuel + air mixture maintained at > ignition temp.  3) => Adequate quantity of air supply to fuel, so that O2 + fuel are thoroughly mixed.  Amount of excess air required is dependent on load.  Furnace cross-section area & design must support full load gas flow rate at ...

BOILER  WATER  CHEMISTRY ( BOILER WATER/ STEAMS ANALYSIS )   The main objective of feed and boiler water treatment in a power plant is to maintain the plant in a condition where it can operate reliably and efficiently. It aims:- a) To maintain the integrity of the feed, boiler and steam system by minimising corrosion to an acceptable level; b) To maintain the effectiveness of heat transfer surface by minimising the deposition of corrosion products & scale; c) To maintain a high level of steam purity and thus prevent problem in the super heaters,   re heaters, & turbine. The water has to be treated to obtain required quality before it is allowed to go into the boiler .The ultra-pure water so obtained is further conditioned in the feed system and then within boiler so that water is not aggressive to any of the variety of construction materials used in boiler, feed and steam cycles.           ...

CW SYSTEM Purpose The purpose of CWP system Presentation   is to provide the operating personnel with necessary information to safely operate and maintain the CWP   system & associated equipment. The scope of the Presentation covers an overview of the CWP System, System   Description, Normal Operation, Start-up / Shutdown, Emergency Operations & Alarms, Instrumentation & Process Control, Interlock & Protection The cooling water pump (CWP) sat   Power system is provided for each unit. & all pumps is   located CW House Building. Overview Purpose of the Circ Water (CW) system The purpose of Circulating Water Pump (CWP) is to remove the heat rejected to the Main Condenser by the low pressure turbines exhaust steam.  CWP transfers the heat from the Main Condenser to the atmosphere via natural  draft cooling towers. NEED OF COOLING TOWER : In Power plant, cooling tower cools down the hot water of Turb...

HP Bypass Station 1:- HP/LP bypass system can handel 60% of boiler load. 2:- HPBP valve is a combined pressure reducing and desuperheating station valve 3:- Spray water is tapped from BFP discharge  and spray controled by spray control valve. 4:- HPBP dumps the depressurised and desuperheated steam with suitable parameter into CRH line. 5:-Can operate without coordinate with turbine. 6:- Allows quick raising of steam parameters at a level acceptable to turbine for rolling operqtion during start up. 7:-Oil supply unit is installed for operation of HPBP & LPBP valves  8:-Supply oil pressure is maintained at 160 kg/cm2 by the pump and accumulator unit. Modes of HP Bypass Operation 1:- Boiler start-up with TG set at stand still. 2:- Rising of steam parameters to a level acceptable to turbine for rolling. 3:- Turbine start-up and loading while steam flow gets transferred to the turbine 4:- Parallel operation with turbine on load rejection. 5:- Allowing boiler...