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Why does vacuum in steam condenser reduce or drop??

  1-High exhaust temperature: Vacuum drops or maintains at lower side due to high exhaust steam temperature flow into steam condenser. This high exhaust temperature is mainly due to 1-Operation of Turbine at lower loads 2-More clearance in labyrinth seals 3-Not operating exhaust hood sprays 4-More load on condenser 5-Breaking of ejector U loop 2-Low circulating cooling water flow Vacuum in condenser reduces due to inadequate cooling water flow through steam condenser. This is mainly due to; 1-Problems associated with pumps 2-Air pockets in pipe line 3-Leakages in cooling water line 4-Stuck of discharge valve of pump 3-High cooling water temperature at condenser inlet Higher cooling water temperature at condenser inlet results into reduction of vacuum due to poor heat transfer from steam to water 4-Poor heat transfer in condenser Very less or poor heat transfer in steam condenser reduces vacuum to very low level resulting into high exhaust temperature &am

16-Perfect reasons for more fuel consumption of Boilers

Following are the 16-reasons for increase in Boilers fuel consumption 1. Decreased economiser inlet feed water temperature: On every 6-8 deg C decrease in Economiser inlet feed water temperature causes the rise in Boiler fuel consumption by 1%. 2. Increased Boiler outlet   flue gas   temperature: On every 22 deg C increase in flue gas temperature causes the reduction in Boiler efficiency by 1% & hence boiler fuel consumption increases for generating same steam. 3. Increased moisture content in the fuel Boilers fuel consumption increases as the moisture in the fuel increases. As it requires more excess air & reduces combustion efficiency leading to unburnt losses 4. Increased excess air 10-Tips to reduce LOI in Boilers Increase in excess air causes dry flue gas loss & hence more fuel consumption. And also leads to more auxiliary power consumption. 5. Increased unburnt loss Unburnt fuel or incomplete combustion of fuel leads to increased consumption of fuel.

Calculated reasons for increase in Turbine specific steam consumption

1. Lower vacuum Turbine consumes more steam, if vacuum in condenser is maintained on lower side. Example:   Consider a 20 MW Steam Turbine having Inlet steam parameters 65 kg/cm2 & 490 Deg C & Vacuum maintained in condenser is -0.9 kg/cm2. Calculate the steam consumption of turbine at vacuum -0.9 kg/cm2 & -0.85 kg/cm2 A-Steam consumption Q at -0.9 kg/cm2 to develop 20 MW power P =Steam flow X( Enthalpy of inlet steam-Enthalpy of exhaust steam)/ 860 Enthalpy of inlet steam at inlet steam parameters =810 kcal/kg Exhaust steam enthalpy at -0.9 kg/cm2 vacuum = 619 kcal/kg Then, 20 = Q X (810-619)/860 Q1 = 90 MT B- Steam consumption Q at -0.85 kg/cm2 to develop 20 MW power Exhaust steam enthalpy at -0.85 kg/cm2 vacuum= 623 kcal/kg Then, 20 = Q X (810-623)/860 Q 2= 90.9 MT It is clear that, Turbine operating at -0.9 kg/cm2 vacuum consumes lesser steam as compared to turbine operating at vacuum-0.85 kg/cm2 2. Lower inlet main stream pressure& temp

Why do the Boilers explode???

  Now days, we are hearing more on explosion in Boilers & related auxiliaries. This is harming man, machines & system and creating unrecoverable situations in power plant. Upon thinking on this following major causes or reasons come into picture. The main reasons for Boiler explosions are; Operating the Boiler more than the design pressure for long time Operating the Boilers at lower water level in drum High furnace pressure Poor water quality Poor maintenance of Boilers in shutdowns Ignoring the aging factors of Boiler parts Operating the Boilers at higher main steam or metal temperature Power plant safety Questions & Answers Viva Questions & answers for preparation of BOE exam & interview 1-What are the reasons for operating the Boilers at more than operating pressure? Malfunction of pressure transmitter or leakages in its impulse line Faulty local pressure gauges Faulty safety valves or safety valves set at higher pressure Improper control of

Protections & Interlocks in power plants

 Interlocks:   Are the programmed or hardwired control systems to protect systems and improve the operation reliability. Protections: Are the programmed or hardwired control systems to protect the equipments, man power and systems from failure/harm. The interlock and protection system is used to ensure safety of equipment and personnel as well as smooth & trouble free operation of the plant This system initiates automatic corrective actions to stabilize the unit quickly. The protection scheme is developed to trip the equipment automatically with or Class A trip involves a serious electrical fault like differential, stator earth fault etc. and is considered to be the most dangerous in terms of the shock on the unit. Since it involves serious electrical faults, connections from both generator and the HV bus is immediately switched off to limit the damage at the fault point and also to isolate the healthy system. Hence the unit (turbine, generator and boiler) has to be tripped