HUMIDITY MEASUREMENT BENEFITS IN POWER APPLICATIONS Boiler Reliability

HUMIDITY MEASUREMENT BENEFITS IN POWER APPLICATIONS Boiler Reliability Interest Group Meeting June 14, 2012 Jeff Bossong, H 2 O Principal jeff. bossong@h 2 oop. com 847 -991 -7488

Objective of Presentation • • • H 2 O Technology Systems Power Plant Applications Humidity 2 Optimization

H 2 O Technology • Absolute Humidity Sensor – Direct measurement of the water molecule – Dipole moment measuring effect – In-situ measurement • Advantages – – – High temperature operation – 850 F High particulate operation Minimal maintenance Corrosive and condensing environments are not an issue Accurate Robust (sensor life is 10 years minimum) Humidity 2 Optimization

Installation Requirements • • • Probe sizes – 490 mm or 1, 470 mm lengths Flange - 4 inch, 150 lb ANSI Power – 110 V, 5 Amps Output Signal – 4. . 20 m. A isolated Measurement unit – g/m 3 corrected to 0 C at process pressure Other Units – Equations are provided (i. e. , dewpoint, RH, humidity ratio) Humidity 2 Optimization

Picture / Drawing Humidity 2 Optimization

PD 215 Applications • Relatively Benign Environments – Pricing: $15, 000 per unit – Temperature limit is 250 F – Applications: environmental reporting, dryer exhaust, stacks, turbine inlet Humidity 2 Optimization

PD 302 Applications • Harsher Environments – Pricing: $26, 000 per unit – Applications: combustion control, blast furnace control, corn wet milling, gasification, scrubber control, curing ovens, steam reformers, industrial dryer control, phosphates, tube leak detection…. Humidity 2 Optimization

Power Plant Applications • Combined Cycle – – Tube leak detection Dewpoint measurement Environmental reporting Power Augmentation Humidity 2 Optimization • Coal / Biomass Fired Boilers – – – – Tube leak detection Soot blower feedback Heat rate calculations Air heater in-leakage Dry scrubber control Environmental reporting Wet scrubber stack protection Pulverizer control

Combined Cycle • Tube Leak Detection – HRSG Outlet – Our detection limit is 0. 1 g/m 3 at 0 C – Volumetric flow rate: 1, 300, 000 m 3/hr – Detection limit = leak / volumetric flow rate – Leak =. 1*1, 300, 000 – Leak = 130, 000 g/hr – Leak = 4. 78 lbs/min or 0. 57 gallons per minute – Process noise includes ambient humidity Humidity 2 Optimization

Combined Cycle • Dewpoint Measurement – HRSG Outlet – Feed water temperature control – Dewpoint equation • • • Pd = (1 -(0. 0001*(SQRT((0. 1*T)+1)+4)))*461. 51*(T+273. 15)*F*0. 00001 Dp = (234. 175*LN(Pd/6. 1078))/(17. 08085 -LN(Pd/6. 1078)) T = Temperature in C F = Absolute humidity at process conditions Pd = Water vapor pressure Dp = Dewpoint temperature – Water dewpoint temperature varies 115 to 135 F – Acid dewpoint is a function of water and SO 3 where sulfur content is almost negligible for natural gas – Feed water is set to 140 F – Corrosion prevention during outages Humidity 2 Optimization

Combined Cycle • Environmental Reporting - Stack – Provides real time, accurate moisture concentration – EPA method 4 is not very accurate and data is a snapshot – Could hurt or help depending on humidity number used for reporting • Power Augmentation – Turbine Inlet – Improved accuracy of dewpoint temperature – Reduce factor of safety so inlet temperature can be lowered without condensation Humidity 2 Optimization

Coal / Biomass • Tube Leak Detection – Economizer Outlet – Our detection limit is 0. 1 g/m 3 at 0 C – Volumetric flow rate: 372, 000 m 3/hr – Detection limit = leak / volumetric flow rate – Leak =. 1*372, 000 – Leak = 37, 200 g/hr – Leak = 1. 37 lbs/min or 0. 17 gallons per minute – Process noise includes ambient humidity, soot blows and fuel moisture – More process noise but lower air flow Humidity 2 Optimization

Coal / Biomass • Economizer Outlet – Soot blower feedback • Safety to assure steam is firing • Protect lances from bending and plant shutdown – Heat rate calculations • Fuel moisture variation • Air heater efficiency Humidity 2 Optimization

Coal Biomass • Air Heater In-Leakage Rate – Economizer Outlet and Air Heater Outlet – Water doesn’t stratify like oxygen: more accurate, real time leakage rate – Equation • • AHI * y + AHA * x = AHO * F , where F=x+y x = (AHI-AHO)*F/(AHI-AHA) AHI = H 2 O reading at air heater inlet AHA = ambient humidity in g/m 3 (manual or real time) AHO = H 2 O reading at air heater outlet F = flow leaving air heater x = volumetric leakage rate y = flow entering air heater – No flow measurement will still provide a relative difference – Acid dewpoint is a function of water and SO 3 Humidity 2 Optimization

Coal Biomass • Dry Scrubber Control – Scrubber Outlet, Baghouse Outlet or Stack – Control to an approach to adiabatic saturation temperature – Better SO 2 removal at lower temperatures improves lime usage – Protects baghouse from corrosion – Moisture variables include sootblow, load change, fuel moisture, ambient air humidity and tube leaks – Dewpoint can vary up to 10 degrees depending upon time of year and conditions Humidity 2 Optimization

Coal / Biomass • Environmental Reporting – Stack – Improved accuracy of emissions – Could hurt or help depending on humidity number used for reporting – Wet Scrubber Stack Protection • Control reheat or bi-pass after scrubber • Water carry over can increase moisture concentration past scrubber outlet dewpoint Humidity 2 Optimization

Coal / Biomass • Pulverizer Control – Pulverizer Outlet – Sensor is a real time input for mass and energy balance across the pulverizer – Sensor will also identify upset conditions, i. e. air flow upsets • Dryer Control – Dryer Outlet – Same as above Humidity 2 Optimization

H 2 O Projects • Other Customers – – – Frito Lay : Dryer and waste heat recovery projects Cargill: Dryer control Dublix: Combustion specialist for WTE plants Foremost Farms: Spray dryer control ADM: Biomass boiler applications US Steel: Cold blast furnace control Humidity 2 Optimization