Absorption Refrigeration Cycle Turbine Inlet Conditioning Luke Buntz Engineer Kiewit Power Engineers Co. 1
Overview 2
Generator Output (MW) The Problem Why chill? Increased fuel efficiency (fewer emissions) Power production capability and turbine efficiency increase as inlet temperature decreases Electricity demand is highest on the hottest days, but as ambient temperature increases air becomes less dense, therefore less power can be produced Power is also the most valuable at these times so recovering power lost due to high ambient provides a significant Return on Investment Why heat? Anti-icing is required in icing conditions to prevent damage to turbine blades 55 50 45 40 35 30 LM6000 PC-SPRINT 80 F Maximum Wet Bulb Temperature Sea Level 25-40 -20 0 20 40 60 80 100 120 Ambient Temperature ( F) Aero-derivatives: Anti-ice systems typically heat air 10 degrees F above ambient temperature, however power capability decreases as temperature decreases below the sweet spot so additional heating enables higher power output At part load, heating of the inlet air improves heat rate and emissions Frames: Anti-icing is typically accomplished by using bleed air from the compressor. This results in a two-fold power reduction: 1. As inlet temperature increases, power production capability decreases 2. Bleed heat robs valuable compressed air from the combustor ( eliminates this need) 3
Generator Output (MW) The Solution Why? Operational Flexibility: Fast Start Capability: On Aero units can be fully chilling or fully heating within 10 minutes of turbine fire Dispatch order: By optimizing the heat rate at the desired power level, plant can be dispatched sooner when preference is given to heat rate Peaking profile: Summer Chill to enable maximum power Winter Heat (beyond anti-icing) to enable maximum power 55 50 45 40 35 30 LM6000 PC-SPRINT 25-40 -20 0 20 40 60 80 100 120 Load following: Ambient Temperature ( F) Varies inlet air temperature to optimize output and heat rate, regardless of ambient temperature Can enable maximum turndown to maintain a lb/hr emissions limitation Ability to improve heat rate/emissions at part load conditions Base load: Constant, maximum power across broad ambient temp range Dry Low Emissions: Reduced fuel mapping (constant inlet temperature) Emissions reduction ( Green Plants) For same NET power production as unit with mechanical chiller, less lb of NOx and CO2 produced For same emissions as unit with mechanical chiller, more NET power available Heat Chill 4
How Does Work? COOLING WATER HEATING VALVE AIR AMMONIA RCVR TCV 6 REFRIGERANT VALVE 5 7 TIAC COILS 4 EVAPORATOR Abbreviations: TIAC Turbine Inlet Air Conditioning TCV Temperature Control Valve HRVG Heat Recovery Vapor Generator CONDENSER SPRAY RCVR 8 3 FUEL LETDOWN COMBUSTION TURBINE 9 HP PUMPS SKID 2 RECTIFIER 10 G 1 HRVG EXHAUST STACK 1. Ammonia-water solution is vaporized in the HRVG 2. The rectifier separates vapor ammonia out the top and liquid water to the bottom 3. The condenser turns the vapor ammonia to liquid 4. The liquid ammonia gathers in the ammonia receiver 5. The high pressure liquid ammonia is expanded in the TCV 6. The ammonia is evaporated, chilling the water-glycol mixture 7. The water-glycol mixture passes through the TIAC coils, chilling the inlet air 8. The vapor ammonia is recombined with the water from the rectifier 9. The ammonia-water solution is pumped back into the HRVG 10. The cycle repeats WATER-COOLED TM PROCESS 2012-06-25 5
Reuses waste product (exhaust energy) For same NET power as mechanical chiller, less lb of NO x and CO 2 Ammonia is naturally occurring, readily available, and inexpensive Ammonia is environmentally friendly: Ozone Depletion Potential (ODP) = zero R-134a = 0 R-123 = 0.02 Global Warming Potential (GWP) = zero R-134a = 1300 R-123 = 90 Better heat rate = more efficient use of fuel Water recovery from inlet coil condensate 6
Time 5:55:15 6:05:45 6:16:15 6:26:45 6:37:15 6:47:45 6:58:15 7:08:45 7:19:15 7:29:45 7:40:15 7:50:45 8:01:15 8:11:45 8:22:15 8:32:45 8:43:15 8:53:45 9:04:15 9:14:45 9:25:15 9:35:45 9:46:15 9:56:45 10:07:15 10:17:45 10:50:19 11:00:49 11:11:19 11:21:49 11:32:19 11:42:49 11:53:19 12:03:49 12:14:19 12:24:49 12:35:19 12:45:49 12:56:19 13:06:49 13:17:19 13:27:49 13:38:19 13:48:49 13:59:19 14:09:49 14:20:19 14:30:49 14:41:19 14:51:49 Ambient Temperature ( F) 70 Mode Transition 60 50 LPC Inlet Air ( F) 40 Ambient Air ( F) TRANSITION CHILLING 30 HEATING 20 10 0 Morning Ambient Temperature: 34 F Afternoon Ambient Temperature: 64 F Although the ambient temperature increased 30 F, compressor inlet temperature only varied 6 F Skid changes modes based on ambient temperature Hands-off, automated transition Only system available that performs both inlet conditioning functions 7
Skid 2000 Ton Unit Rectifier Skid mounted PLC/MCC Closed-loop Redundant pumps 40 long x 14 wide No large components or compressors (eliminating 4160V switchgear) Low maintenance/operation costs LP Pumps HP Pumps PLC/MCC Panel 8
Simple Cycle Units 9
Percent of Rated Output (%) Simple Cycle Output 120 120 115 115 110 110 105 105 100 100 95 95 90 85 7FA.04 Base LM6000 Base SGT6 5000F(4) 7FA.04 LM6000 SGT6 5000F(4) 90 85 80 75 80 F Maximum Wet Bulb Temperature Sea Level 75 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Ambient Temperature ( F) 80 10
Percent of Rated Heat Rate (%) Simple Cycle Heat Rate 106 105 80 F Maximum Wet Bulb Temperature Sea Level 106 105 104 104 103 103 102 102 101 101 100 100 99 99 98 98 97 96 7FA.04 Base LM6000 Base SGT6 5000F(4) 7FA.04 LM6000 SGT6 5000F(4) 97 96 95 95 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Ambient Temperature ( F) 11
GE Frame Simple Cycle Summary Worst Better Best Base Evaporative Mechanical Cooling Chiller Output Gain 158,107 8.7% 14.8% 21.1% 7FA.04 Heat Rate Reduction* 10,310-0.1% 3.2% -2.2% Efficiency Improvement 33.1% 0.0% -1.0% 0.8% 7FA.05 7EA Output Gain 192,594 7.9% 10.6% 16.1% Heat Rate Reduction* 10,085-1.2% 2.1% -2.8% Efficiency Improvement 33.8% 0.5% -0.8% 1.1% Output Gain 75,360 8.3% 15.0% 22.6% Heat Rate Reduction* 11,812-1.8% 1.8% -4.5% Efficiency Improvement 28.9% 0.6% -0.6% 1.5% * Heat rates based on fuel HHV Based on a 100 F day with 35% Relative Humidity Mechanical Chiller parasitic load is based on 1.6 kw/ton parasitic load is based on 0.11 kw/ton 12 Revision:
GE Aero Simple Cycle Summary Worst Better Best Revision: LM6 PCS LM6 PGS LM6 PHS LMS PA LMS PB LM25 +G4 Base Evaporative Mechanical Cooling Chiller Output Gain 37,606 20.3% 28.1% 35.6% Heat Rate Reduction* 9,868-4.6% -0.2% -5.7% Efficiency Improvement 34.6% 1.8% 0.1% 2.3% Output Gain 43,887 13.8% 24.7% 32.1% Heat Rate Reduction* 9,793-2.7% 2.5% -3.2% Efficiency Improvement 34.9% 1.1% -0.9% 1.3% Output Gain 41,653 7.7% 17.3% 25.1% Heat Rate Reduction* 9,713-1.9% 1.8% -4.5% Efficiency Improvement 35.1% 0.7% -0.7% 1.8% Output Gain 93,917 4.0% 8.4% 10.8% Heat Rate Reduction * 9,011-1.1% -0.7% -2.8% Efficiency Improvement 37.9% 0.5% 0.3% 1.2% Output Gain 83,912 4.4% 11.2% 16.8% Heat Rate Reduction * 8,997-1.3% 0.4% -4.4% Efficiency Improvement 37.9% 0.6% -0.2% 2.0% Output Gain 26,006 13.7% 22.1% 30.2% Heat Rate Reduction * 10,373-3.1% 0.6% -5.7% Efficiency Improvement 32.9% 1.1% -0.2% 2.2% * Heat rates based on fuel HHV 13
Contacts Chris Mieckowski Product Line Manager 913.928.7304 Chris.Mieckowski@Kiewit.com Luke Buntz Engineer 913.689.3931 Luke.Buntz@Kiewit.com 14 These values are based on power production at the generator terminals minus the parasitic loads of the inlet conditioning and some SCR tempering loads.