Hybrid Instrument Air Dryer An Innovative Solution to Save Energy, Improve Reliability and Reduce Maintenance Cost Abdulmajeed Alshaye, Saudi Aramco 12/06/2017 2017, Saudi Aramco
Contents Objective Introduction to IA (instrument air) Challenges with the IA system High air temperature effect on desiccant dryer Hybrid dryer configuration Summary 2
Objective To share with you a new concept of compressed air drying: Use the minimum amount of energy to operate Ensure a constant, low and reliable outlet dew point Safe failure mode Low maintenance and operation cost 3
Introduction to IA PA Compressor After cooler Separator Wet receiver Pre-filter Dryer IA Unit A Unit B After filter Unit C Unit D Unit E Dry receiver Dry receiver Dew point 4
Introduction to IA Q. How much compressed air cost us? η= EEEEEE ssssss ii cccccccccc aaa EEEEEE iiiii ii the mmmmm [CATEGOR Y NAME] [VALUE] [CATEGOR Y NAME] [VALUE] [CATEGOR Y NAME] 10% Heat of compressi on; 80% 1 hp (Final use) 10 hp (Motor) 30 hp (Power plant) 5
Challenges with IA High IA losses (up to 50%) High outlet dew point (+70 F) Header pressure fluctuation (15%) Frequent dryer valves failures Plant safety Process interruption High maintenance cost Less redundancy Condensate drainage Portable compressor rental 6
Challenges with IA (high losses) Flow rate, scfm 14000 12000 10000 8000 6000 4000 2000 Total production Total consumption (IA+PA) 0 7
Challenges with IA (dew point) 70 60 Dew point trend on May 26, 2016, midnight 50 Dew point, F 40 30 20 10 0 ۲:۰۰ ۲:۱۰ ۲:۲۰ ۲:۳۰ ۲:٤۰ ۲:٥۰ ۳:۰۰ ۳:۱۰ ۳:۲۰ ۳:۳۰ ۳:٤۰ ۳:٥۰ ٤:۰۰ 8
Challenges with IA (pressure swinging) 110 Header pressure (PSI) 105 100 95 90 ۱۳:۰۰ ۱۳:۰٤ ۱۳:۰۸ ۱۳:۱۲ ۱۳:۱۷ ۱۳:۲۱ ۱۳:۲٥ ۱۳:۲۹ 9
Challenges with IA (filters damage) Dryer after filter Dryer after filter Dryer pre-filter Plant instruments 10
Challenges with IA (condensate drain) 11
High air temperature effect (dryer Inlet) 1. High energy consumption 2. Dryer valve malfunctioning 3. Short desiccant life 4. Filters damage 5. Not meeting IA quality requirement (ISO 8573) 12
High air temperature effect (dryer Inlet) 150 140 Temperature, F 130 120 110 Example for dryer inlet temperature 100 90 13
High air temperature effect (dryer Inlet) 14 27/10/2014 Copyright note text (8pt)
High air temperature effect (Dryer Inlet) 50.0 45.0 47.1 Air water content for 5,000 scfm at 132 PSIA 40.0 Water content gal/hr 35.0 30.0 25.0 20.0 15.0 10.0 5.0 32.2 24.6 19.61 14.7 11.4 8.4 6.4 4.5 3.4 2.3 1.6 0.0 ۱٥٦ ۱٤۰ ۱۳۰ ۱۲۰ ۱۱۰ ۱۰۰ ۹۰ ۸۰ ۷۰ ٦۰ ٥۰ ٤۰ Air temperature in Degree F 15
Hybrid dryer configuration This innovative system is relying on two concepts 1. Precooling the compressed air before the desiccant dryer 2. Utilize a external purge heated type desiccant dryer Cooling + Adsorption Working In Series Complement & Independent 16
Hybrid dryer configuration 5,000 scfm, 125 psi of compressed air To PA Air compressor 300 Plant cooling water Chilled water 250 F 140 F 70 F 1 2 3 86% To IA PDP:5 F Air temp. / water content 250 200 150 100 50 250 F 47 G/h 1st aftercooler 2st aftercooler [VALUE] F [VALUE] F [VALUE] G/h Cyclone Heated desiccant dryer 90 0 [VALUE] G/h [VALUE] G/h 17
Traditional dryer configuration Heatless dryer design Purge losses > 20% Switching time: 5 minutes Valves are prone to failures Using single aftercooler 18
Hybrid dryer configuration 19
Hybrid dryer configuration Adsorption dryer and refrigeration dryer High capital cost High pressure drop Low flexibility 20
Hybrid dryer configuration (chiller + dryer) 21
Hybrid dryer configuration (aftercooler) 22
Hybrid dryer configuration (benefits) 1. Reduce the compressed air losses in the utility to less than 2% (now 30-50%). 2. Increase the desiccant dryer switching time from 5 minutes to 48 hours. 3. Significantly improve the quality of the delivered instrument air dew point. 4. Provide dry air for plant air application. 5. Reduce the maintenance cost. 6. Increase instrumentation reliability. 7. Minimize process interruption. 8. Produce pure water as a byproduct. 9. Reduce instrument air pressure fluctuation. 10. Condense the majority of harmful gases in the air. 23
Summary Compressed air is inherently energy inefficient Hybrid dryer design is well suited for hot and humid locations Benefits: Energy, Safety, Reliability, Environment, Asset integrity Availability, Maintenance cost and Compliance Flexible operation Existing plants or new projects Potential energy saving (kingdom): 150 Mw 24
Thank you 25