I N D U S T R Y A P P L I C A T I O N S S E R I E S A Guide to Level Instrumentation for Power Generating Plants

POLLUTION CONTROL SYSTEM RAW COAL TURBINES STEAM BOILER CONDENSER SO2 REMOVAL COAL STORAGE . . . . . . . . . . . . .6 NATURAL GAS SEPARATOR . . . .6 FUEL OIL STORAGE . . . . . . . . . .7 AMMONIA STORAGE . . . . . . . . . .7 CONDENSER HOTWELL . . . . . . .8 CONDENSATE STORAGE . . . . . .8 1 DEAERATOR . . . . . . . . . . . . . . . . .9 FEEDWATER HEATERS . . . . . . .10 STEAM DRUM . . . . . . . . . . . . . .10 CONDENSATE DRIP LEGS . . . . .11 BOILER BLOWDOWN TANK . . .12 FLASH TANK . . . . . . . . . . . . . . . .12 Level Controls in a Coal-Fueled Plant 1 PULVERIZER COAL SILO COMBUSTION FUEL SYSTEM...

WATER TREATMENT GENERATOR POWER CONVERSION SYSTEM CIRCULATING WATER SYSTEM SOURCE WATER . . . . . . . . . . . .13 DEMINERALIZATION . . . . . . . . .14 MAKE-UP WATER . . . . . . . . . . . .14 SERVICE WATER . . . . . . . . . . . .15 OPEN SUMPS . . . . . . . . . . . . . .16 COOLING TOWER . . . . . . . . . . .16 LUBRICATION OIL TANK . . . . . .17 WATER WASH TANK . . . . . . . . .17 COOLING TOWER 13 14 15 16 17 18 Please Note: The level instruments recommended in this guide are based on field experience with similar applications and are included as a general guide to level control selection. Because...

GAS TURBINE CONDENSER Level Controls in a Combined-Cycle Plant STEAM TURBINE HRSG HEAT RECOVERY STEAM GENERATOR FUEL 9 5 6 8 7 KEY LEVEL APPLICATION PAGE KEY LEVEL APPLICATION PAGE 3 POST COMBUSTION SYSTEM COMBUSTION FUEL SYSTEM STEAM GENERATING SYSTEM NATURAL GAS SEPARATOR . . . .6 FUEL OIL STORAGE . . . . . . . . . .7 AMMONIA STORAGE . . . . . . . . . .7 CONDENSER HOTWELL . . . . . . .8 CONDENSATE STORAGE . . . . . .8 DEAERATOR . . . . . . . . . . . . . . . . .9 FEEDWATER HEATERS . . . . . . .10 HRSG DRUM . . . . . . . . . . . . . . .10 CONDENSATE DRIP LEGS . . . . .11 FLASH TANK . . . . ....

WATER TREATMENT GENERATOR POWER CONVERSION SYSTEM CIRCULATING WATER SYSTEM SOURCE WATER . . . . . . . . . . . .13 DEMINERALIZATION . . . . . . . . .14 MAKE-UP WATER . . . . . . . . . . . .14 SERVICE WATER . . . . . . . . . . . .15 OPEN SUMPS . . . . . . . . . . . . . .16 COOLING TOWER . . . . . . . . . . .16 LUBRICATION OIL TANK . . . . . .17 WATER WASH TANK . . . . . . . . .17 COOLING TOWER 13 14 15 16 17 18 Please Note: The level instruments recommended in this guide are based on field experience with similar applications and are included as a general guide to level control selection. Because...

One hundred years ago, electric power was over 20 cents a kilowatt-hour— more than twenty times today’s cost. Back then electricity was used primarily in cities for lighting streets and powering streetcars. The cost of electric power was well beyond the means of most families. Even rudimentary appliances were absent from American homes. But the 20th century brought Power to the People through improved power-generating technology. By century’s end, affordable electricity was available to all Americans. As the power industry matured, a Chicago company that first marketed its level controls for...

Application: Raw coal is delivered to a coal yard in aggregate pieces of approximately 6" that are later reduced in size by a crusher to approximately 1.5". Enclosed storage of crushed coal is common in frigid climates and where containment of coal dust is controlled to protect populated areas. Hoppers and silos store active and reserve crushed coal prior to its pulverization into the powdered form suitable for boiler combustion. Challenges: Some severe power plant accidents in years past have been traced to coal dust ignition, and the atmospheres of contained coal storage areas are highly congested...

Application: Fuel-fed ignitors initiate the boiler flame in coal-fed plants using natural gas or atomized fuel oils such as light grade #2 or heavy grade #6. Natural gas and propane can also be used. In combined-cycle plants, gas turbines often use natural gas and liquid fuel oils as ignition fuel. Large gas turbines are designed to operate alternately or simultaneously with both gas and liquid fuels. In dual-fuel plants, a False Start Tank will temporarily hold diesel fuel after an unsuccessful attempt to fire the turbine. Challenges: Crude oils with lower flash points represent a greater fire...

Application: Steam enters the condenser where it cools and condenses into water before being sent to the low-pressure feed-water heater. The condenser hotwell serves as a water reservoir for the turbine cycle. When hotwell level reaches the low point, a valve opens to supply make-up water to the cycle. When hotwell level reaches the high end of the level range, a dump valve opens to move the condensate from the hotwell to a condensate storage tank. Challenges: Water loss in the turbine cycle due to leakage, steam venting or other usage depletes make-up water. Level control in the hotwell ensures...

Application: The deaerator is an open-faced water heater which removes non-condensable gases from the feedwater. In addition to the condenser hotwell, the deaerator's storage tank is the remaining reservoir in the turbine cycle. Positioned below the deaerator and before the boiler feed pumps, the deaerator storage tank serves as a surge tank for the boiler feedwater. Tank level is often controlled by a control valve on the condensate supply line to the deaerator. Challenges: Pressure fluctuations are extensive in the deaerator storage tank and result in flashing. Level controls must contend with...

Application: Feedwater heaters use extraction steam from the turbine to raise the temperature of water destined for the boiler. Water first passes through low-pressure heaters and into the deaerator where excess oxygen is removed. The feedwater then passes into the high-pressure heaters where it is further heated and pressurized. Two separate level control loops should manage each feedwater heater—according to ASME standards. Challenges: Feedwater heater level is controlled to (1) prevent level from rising into the extraction line; (2) keep the tube surfaces in the condensing zone immersed; and...