Pharmaceutical Facility Design

Transcription

1 PhEn-602 Pharmaceutical Facility Design J. Manfredi Notes #10 PhEn 602 Spring

2 Moisture Methods of dehumidification Limits of cooling-based dehumidification Desiccant dehumidification Types of desiccant driers Application of desiccant dehumidification Desiccant vs. refrigerant based dehumidification How to decide? PhEn 602 Spring

3 Cooling-Based Dehumidification (Sensible Cooling and Dehumidification) 45 F 44 gr/lb 70 F 56 gr/lb Maximum moisture content is proportional to air temperature Cooling the air removes moisture by condensation Sensible Cooling Dehumidification Process air PhEn 602 Spring

4 Direct Expansion Cooling Compressor raises the pressure and temperature of the refrigerant gas Refrigerant is condensed back to a liquid, releasing its heat to the air passing through the condenser coil Compressor Refrigerant Condenser Refrigerant Expansion Valve Liquid Refrigerant Storage Refrigerant expands inside the coil, removing heat from the air passing through the fins Refrigerant Evaporator PhEn 602 Spring

5 Chilled Water, Glycol & Brine Cooling Compressor Refrigerant Condenser Refrigerant Expansion Valve Liquid Refrigerant Storage Refrigerant Evaporator (Chiller Barrel) Refrigerant cools a heat transfer liquid, which in turn circulates through coils to cool the air PhEn 602 Spring

6 Cool-Reheat Dehumidifier Evaporator (Air Cooler) Condens er (Air Heater) Concept used in basement dehumidifiers Cooling and dehumidifcation thru the evaporator Sensible reheating thru the condenser PhEn 602 Spring

7 Desiccant Dehumidification With cooling-based dehumidification, it is possible to reach 45 F dew point using chilled water, and 40 F dew point using refrigerant (DX) coil. Can achieve lower dew points (lower humidity ratios) with desiccant dehumidification than cooling-based dehumidification. Theoretically, desiccant dehumidification runs along a constant enthalpy line. In actuality, there is a slight rise in the enthalpy. PhEn 602 Spring

8 Desiccant Dehumidification Dehumidification Process air Latent Heat Conversion PhEn 602 Spring

9 Desiccant Dehumidification Moisture leaves the air stream due to difference in vapor pressure Low vapor pressure at surface of desiccant Vapor pressure of water in air is higher than at surface of desiccant Moisture moves from the air stream to the desiccant Most solid materials attract and hold moisture PhEn 602 Spring

10 Desiccant Dehumidification Desiccants are unique they can hold 10-10,000 % their weight in water vapor. Desiccant vapor pressure (VP) varies with temperature At high temp s, VP is high, and the desiccant gives off vapor At low temp s, VP is lower and absorbs moisture Vapor moves from air to the desiccant and back again based on vapor pressure differences PhEn 602 Spring

11 Desiccant Dehumidification Process air: Air stream to be dehumidified is ultimately delivered to the space. Reactivation air: Air heated by thermal energy (e.g. steam, or electric coils) used to raise the temperature of the desiccant so that it liberates the moisture. Reactivation air regenerates the desiccant PhEn 602 Spring

12 Desiccant Dehumidification the process Desiccant Sorption PhEn 602 Spring

13 Desiccant Dehumidification the process Desiccant Reactivation PhEn 602 Spring

14 Desiccant Dehumidification the process Desiccant Cooling PhEn 602 Spring

15 Packed Tower Desiccant Dehumidifiers 250 F 200 F Desiccant heater Reactivation air in F 95 F Packed tower Packed tower 1 50 F 1 2 Sorption Process Air Out 3 2 Desorption Mosture Content of the Desiccant Reactivation air out Desiccant cooler Process Air In 3 1 Cooling PhEn 602 Spring

16 Packed Tower Advantages & Limitations Advantages Very low dew points (-40( to -100 F) obtained No need for continuous reactivation in low-load load applications Process air can be pressurized without leakage concern Limitations Very large for a given air flow comparatively PhEn 602 Spring

17 HoneyCombe Desiccant Dehumidifiers 2 3 Desorption Desiccant Heater 250 F 200 F 3 1 Cooling F 95 F 1 2 Sorption 1 50 F Mosture Content of the Desiccant PhEn 602 Spring

18 HoneyCombe Dehumidifier Components Electrical Controller Reactivation Heater Reactivation Filter F Reactivation Fan Reactivation Damper Process Damper F Process Filter Process Fan Desiccant Air Seals Desiccant Wheel Desiccant Drive System PhEn 602 Spring

19 Rotary Horiz.. Bed Desiccant Dehumidifiers 1 2 Sorption 2 3 Desorption Horizontal rotating desiccant bed Desiccant heater Process Air Entering 250 F 200 F F 3 Cooling F 50 F 1 Mosture Content of the Desiccant PhEn 602 Spring

20 Rotating Bed Advantages & Limitations Advantages Comparatively low first cost Low cost desiccant replacement Disadvantages Rather large for a given air flow Parallel air flow rather than counter flow Required to prevent air leaks Uses twice as much energy as other types Dew points below 0 F not normally practical Desiccant settles & fractures, requiring replacement Air channels through the bed, reducing effective capacity PhEn 602 Spring

21 Multiple Vertical Bed Desiccant Dehumidifiers 2 3 Desorption Desiccant heater 250 F 200 F F Process Air Entering 3 Cooling Mosture Content of the Desiccant 95 F 50 F 1 2 Sorption Multiple vertical beds PhEn 602 Spring

22 Liquid Spray Desiccant Dehumidifiers 250 F 200 F Conditioner (Process Air) F 95 F 50 F 1 Mosture Content of the Desiccant 1 2 Sorption Regenerator (Reactivation Air) 3 1 Cooling 2 3 Cooling PhEn 602 Spring

23 Liquid System Advantages & Limitations Advantages Immense capacity x desiccant weight in water Internal cooling of desiccant is very energy efficient Air leaves at a constant, low temperature Liquid kills microbes Single regenerator with multiple conditioners saves first cost Can use low-temperature reactivation Limitations Very large, costly & complex to install Sensitive to maintenance & winter solidification Dew points below 15 F not normally practical Corrosive desiccant can carry over into process air High cost of replacing desiccant solution High-temperature reactivation energy must be reduced to a low temperature PhEn 602 Spring

24 HoneyCombe Advantages & Limitations Advantages Lowest dew point of all atmospheric pressure units (-55 F)( Lowest reactivation energy consumption Most reliable mechanically very low maintenance Most compact for a given air flow Effective across a broad range of conditions & applications Several desiccant choices available Limitations Desiccant wheel costs more than granular desiccant First cost sometimes greater than other types PhEn 602 Spring

25 Comparing Dehumidifiers By Leaving Air Dew Point DXCooling Chlled Water Chilled Glycol/Brine Liquid Spray Packed Tower Rotating Tray Multiple Vertical Bed HoneyCombe Air dewpoint delivered continuously ( F ) PhEn 602 Spring

26 Cooling vs. Desiccant Dehumidifiers Most economical when used in combination Factors favoring cooling based dehumidification: Low electrical cost (below 5 /kwh) Humidity control at high temperatures Need for high relative humidity (e.g. fruit) PhEn 602 Spring

27 Benefits of Dehumidification Operational Cost Reduction Interruption costs Re-work costs Energy costs Maintenance costs Reduced Capital Costs Reduced need for plant expansion Reduced equipment replacement cost Reduced HVAC system cost Improved Product Value Value of improved market image Reduced scrap rate Improvement in properties Operational Response Avoid unscheduled maintenance Less equipment required Product value increased by safe storage to meet peak demand PhEn 602 Spring

28 Minimizing Costs Minimizing Installed Costs Reduce moisture loads Optimize control levels Specify tolerances clearly Combine desiccant DH with cooling DH Minimizing Operating Costs Modulate reactivation in response to load changes Use multiple systems for intermittent PhEn 602 Spring

29 Humidity Control Advantages Corrosion Prevention Condensation Prevention Mold & Fungus Prevention Moisture Regain Prevention Product Drying Dry Cooling Food Processing Pharmaceutical Processing PhEn 602 Spring

30 Corrosion Prevention Military Storage Reduces storage losses Cuts storage energy cost Allows immediate equipment use Lithium Battery Mfg Entire rooms at 70 F, 1% rh Volume production now practical Power Plant Lay-up Saves cost over nitrogen Reduces safety hazards Rapid plant start-up Electronics Storage May improves MTBF May reduce calibration frequency May improve reliability PhEn 602 Spring

31 Condensation Prevention Ice Rinks Prevents soft ice & puddles Eliminates fog Reduces refrigeration energy Injection Molding Prevents mold sweat Cuts cycle time in half Lengthens mold life Water Treatment Plant Eliminates rusting Reduces painting requirements Eliminates fungal growth Surface Prep & Coating Coating in any weather No need to coat in sections Improves coating life PhEn 602 Spring

32 Mold & Fungus Prevention Archival Storage Protects organic materials Stabilizes wood artifacts Saves color film Reduces storage energy cost Seed Storage Improves Germination Lengthens Storage Life Eliminates Afaloxin Improves Vigor Cargo Protection Reduces transit losses Avoids litigation expense Protects ship structure Breweries Improves plant sanitation Eliminates fungal contamination Improves plant safety PhEn 602 Spring

33 Moisture Regain Prevention Candy Packaging Eliminates sticking & picking Reduces machine clogging Reduces cleaning frequency Glass Laminating Reduces autoclave time Eliminates bubbles in glass Simplifies PVB film Clean Rooms Allows non-stop production Eliminates tablet press clogging Eliminates photoresist swelling Composite Mfg Speeds part curing time Eliminates vapor voids Extends polyimide epoxy pot life Improves part strength & adhesion PhEn 602 Spring

34 Product Drying Candy Coating Speeds production rate Improves surface finish Eliminates picking Plastic Resin Drying Eliminates vapor bubbles Improves part finish Improves part strength Investment Castings Eliminates solvents Solvent-speed drying rates Avoids part deformation Fish Drying Avoids bacterial growth Dries regardless of weather Improves product texture PhEn 602 Spring

35 Dry Cooling Supermarkets Eliminates product frost Reduces annual energy cost Improves customer comfort Advanced HVAC Systems Eliminates latent load at low cost Uses cogen & waste heat Improves refrigeration COP Sick Buildings Desiccates Legionella bacteria Eliminates condensate scum Eliminates fungal growth in duct work Hotel & Motels Eliminates musty odors Eliminates wall replacement Improves sanitation PhEn 602 Spring

36 Food Processing Candy Packaging Avoids clogged equipment Reduces cleaning frequency Allows fast wrapping with polypropylene Spiral Freezers Eliminates conveyor defrost Eliminates floor icing Improves refrigeration COP Low-Temperature Drying Improves product quality Fast drying at low temperature Candy Pan Coating Improves surface finish Speeds water-based drying Eliminates picking & sticking Spray Drying/Instantizing No clogs in product collectors Allows smaller fluid beds Increases throughput of towers PhEn 602 Spring

37 Pharmaceutical Processing Tableting Presses Eliminates moisture regain Allows faster press speed Allows constant production rate Lyophilizer Rooms Prevents moisture regain Avoids need for glove boxes Improves shelf life Spray Drying Consistent production Reduced size of fluid bed Allows low-temp drying Tablet Coating Allows reduction of solvents Consistent drying in all climates & seasons Powder Compounding Eliminates moisture regain Simplifies handling Improves sanitation Storage Allows low rh in cold storage Prevents cardboard regain Extends storage life PhEn 602 Spring

38 Calculating Moisture Loads Choose the moisture control level Identify moisture load sources Quantify each load source Total the load & compare to the budget Adjust the calculation assumptions & recalculate Key Point: The only correct moisture load calculation is the one made after all parties agree on all assumptions PhEn 602 Spring

39 The Importance of Design Conditions Surrounding space controlled at 70 50% rh = 55 gr/lb Room controlled at 70 2% rh = 2.1 gr/lb Weather condition 90 F & 95gr/lb The Greater The Moisture Differential The Larger The Moisture Load (Just Like Temperature) 95 gr/lb =.64"Hg 55 gr/lb =.37"Hg.36"Hg.27"Hg.63"Hg Vapor Pressure Differential 2.1 gr/lb =.01"Hg PhEn 602 Spring

40 Choosing the Design Conditions Inside Conditions - How Dry? Dry enough to achieve the maximum economic benefit, and no drier Humidity control project is often the result of summer problems. So, what is the moisture condition during the winter when no problem exists? When in doubt, test different conditions with a rental unit Weather Conditions - How Much Safety? How many hours can you risk being out of control? 1% of 2928 summer hours = 29 hours 2.5% of 2928 summer hours = 74 hours Extreme summer temperature usually does not coincide with extreme moisture ASHRAE weather data being revised to reflect that fact PhEn 602 Spring

41 Estimating Weather Design Moisture Design Assumption: ASHRAE 1% Summer Design 95 F db,78 F wb 3. 80% rh 4. Design Moisture 137 gr/lb Dry bulb temperature ( F) F db F wb PhEn 602 Spring

42 Moisture Load Sources Internal Loads Vapor Permeation through walls, floor & ceiling Evaporation and respiration from people Desorption from moist products Evaporation from wet surfaces Vapor as a product of combustion Humid air infiltration through cracks, holes & door openings External Loads Vapor carried into the system by moist ventilation air PhEn 602 Spring

43 Vapor Permeation (The Smallest Load) 56 gr/lb equals inhg 1.8 gr/lb equals inhg inhg Vapor Pressure Difference Wp = P x A x ( VP) Permeance (gr/hr) Difference in vapor pressure across the material (inhg) Surface area of the material (sq.ft.) Material permeance factor (gr/hr/sq.ft./inhg) PhEn 602 Spring

44 Moisture From Products & Packaging 12% 6% Relative Humidity Wpp = lbs/ hr x (pw 2 pw 1 ) Water vapor from products & packaging (lbs/hr) Total mass of material entering the room every hour (lbs/hr) Equilibrium moisture content of material before entering the space (lbs/lb) Equilibrium moisture content of material at the control condition in the space (lbs/lb) PhEn 602 Spring

45 Batch Process Loads Walls, floor, ceiling Initial pull-down Batches of moist product Air relative humidity Temporary equilibrium Time Final equilibrium Product load Walls, floor & ceiling load Building structure requires time to dry. Product dries in stages: Surface moisture - rapid Temporary equilibrium - no load Final drying - low load Time PhEn 602 Spring

46 Moisture From People Seated Standing Light Work Moderate Work Wn = (Pa x Fa) + ( Pb x Fb) + (Pcx F ) + (Pd x Fd) c Moisture load from respiration and perspiration (gr/hr) Load for people at moderate work (gr/hr Load for people at light work (gr/hr) Load for people standing (gr/hr) Evaporation per person (gr/hr) Load for people sitting (gr/hr) Number of people seated PhEn 602 Spring

47 Moisture From Combustion Wg= G x 650 Moisture load from gas combustion (gr/hr) Moisture produced per cubic foot of gas burned (gr/hr) Gas firing rate (cu.ft./hr) PhEn 602 Spring

48 Moisture From Wet Surfaces Transverse flow (Ht) Saturated air at the boundry layer Parallel flow (Hp) Latent heat transfer rate (Btu/hr/sq.ft./in.Hg.) Total surface area wetted (sq.ft.) Vapor pressure of air saturated at the water temperature (in.hg.) Water vapor pressure in the air above the surface (in.hg.) = x x x Grains of water vapor in a pound of water Latent heat of vaporization at the water temperature (Btu/lb) Evaporation load from a wet surface (gr/hr) PhEn 602 Spring

49 Air Leaks Through Cracks Less Humid More Humid Pipe Penetration Moisture carried through cracks in an exterior wall (gr/hr) Wi= Qx d x ( M o M ) i x L Air density (lb/cu.ft.) Length of the opening (Linear ft.) Moisture inside the wall (gr/lb) Moisture outside the wall (gr/lb) Air leakage rate (cu.ft./hr/ln.ft.) PhEn 602 Spring

50 Typical Air Leak Paths Air Handling System Air duct joints Access panels in air handling equipment Ventilation louvers in doors Unused exhaust fans and back-draft dampers Window air conditioners Room Construction Wall-to to-ceiling, wall-to to-floor joints Cracks around doors; especially at the floor Open construction above suspended ceiling tiles Wall penetrations for electrical boxes, conduits, pipes & light fixtures Vapor barrier plastic sheets, not joined PhEn 602 Spring

51 Humid Air From Door Openings Remember: pressure differences do not prevent moisture travel Less humid More humid Wi = A x d x 60 xva x(m o M i ) Moisture load from air infiltrating through an opening (gr/hr) Area of the opening (sq.ft.) Moisture inside the space (gr/lb) Moisture outside the space (gr/lb) Air velocity through the opening (ft/min) Minutes per hour Density of the infiltrating air (lb/cu.ft.) PhEn 602 Spring

52 Humid Air From Airlock Openings Less humid More humid Wi = (h x l w) d M o M i x x x( ) 2 Moisture level inside the room (gr/lb) Moisture level outside the room (gr/lb) Density of air (lbs/cu.ft.) Height, width and length of the airlock (cu.ft.) Moisture infiltration per airlock opening (gr/hr/opening) PhEn 602 Spring

53 Humid Air Through Conveyor Openings Less Humid More Humid Wi = V x Ax d x 60 x (M o M ) i Moisture carried by air through a conveyor opening (gr/hr) Moisture inside the room (gr/lb) Moisture outside the room (gr/lb) Minutes per hour Air density (lb/cu.ft.) Conveyor opening area (sq.ft.) Conveyor velocity (ft/min) PhEn 602 Spring

54 Ducted Openings Less humid High velocity airstream More humid Low Pressure Areas Low Pressure Areas Even with a high exit velocity, moist air can infiltrate into a dry room To minimize counterflow infiltration, move low-pressure areas away from the room by ducting the openings PhEn 602 Spring

55 Humid Ventilation Air (The Largest Moisture Load) 160 Supermarket (15 cfm/person) Hospital Patient Room (25 cfm/person) ASHRAE Standard Defines recommended ventilation rates for commercial and residential spaces Industrial ventilation rates are not defined by ASHRAE because of varying contaminant levels in industrial process Assume ASHRAE Standard 62 as a minimum in the absence of industrial guidelines Cubic Feet Per Minute Ventilation Air Wm= Q x dx 60 x (M - o M ) i Moisture load from fresh air (gr/hr) Moisture level inside the room (gr/lb) Moisture level of the fresh air (gr/lb) Minutes per hour Air density (lb/cu.ft.) Sum of airflows necessary for ventilation, pressurization and exhaust air make-up (cfm) PhEn 602 Spring

56 The Humidity Variable In Air Constituents of Atmospheric Air (In STEADY Concentrations) 78% Nitrogen 20.9% Oxygen 1% Argon Neon Helium Methane Krypton Hydrogen Nitrous Oxide Xenon Constituents of Air (Present in VARIABLE Concentrations) Controlling the moisture content of air accounts for a major portion of the $40 billion air conditioning market Water Vapor 0 to 7% Ozone Sulfur Dioxide Carbon Dioxide Nitrogen Dioxide 0 to 0.15% PhEn 602 Spring

57 Design Conditions Dry Bulb Temperature Dewpoint Humidity Ratio Vapor pressure Weather Extremes Ground Internal Conditions Summer Winter Water Room Building Elevation ft. above sea level standard air density = lb/cu.ft. PhEn 602 Spring

58 Vapor Permeation Surface Area (sq.ft.) Permeance Factor (gr/hr/sq.ft.) Larger Vapor Pressure (in.hg) Smaller Vapor Pressure (in.hg) Permeation Load (gr/hr) Wall 1 Wall 2 Wall 3 Wall 4 Floor Ceiling 400 x x ( ) = 4 gr/hr 400 x x ( ) = 4 gr/hr 600 x x ( ) = 13 gr/hr 600 x x ( ) = 6 gr/hr 2400 x 0.45 x ( ) = 572 gr/hr 2400 x 0.45 x ( ) = 400 gr/hr Total 999 gr/hr PhEn 602 Spring

59 Products & Packaging Item Entry Rate (lb/hr) Original Moisture Content ( lb/lb ) Final Moisture Content ( lb/lb ) Grains Per Pound Moisture Load (gr/hr) Item 1 Item 2 Item 3 Item 4 15 x ( ) x 7000 = 7350 gr/hr x ( - ) x 7000 = gr/hr x ( - ) x 7000 = gr/hr x ( - ) x 7000 = gr/hr Total 7350 gr/hr PhEn 602 Spring

60 Personnel Number Of People Moisture Load ( gr/hr/person) Moisture Load (gr/hr) Seated x = gr/hr Standing x = gr/hr Light work x = gr/hr Moderate work 5 x 5500 = 27,500 gr/hr Room visitors 3 x 5500 = 16,500 gr/hr Total 44,000 gr/hr PhEn 602 Spring

61 Door & Airlock Openings Door Openings Airflow Velocity (fpm) Open Area (sq.ft.) Air Density (lb/cu.ft.) Time Open (min/hr) Air Moisture Outside (gr/lb) Air Moisture Inside (gr/lb) Moisture Load (gr/hr) 50 x x x 8 x ( ) = 22,385 gr/hr x x x x ( - ) = gr/hr Air Lock Openings Airlock Dimensions (ft) Height Length Width Air Density (lb/cu.ft.) Opening Frequency (openings/hr) ( 8 x 8 x 8 ) x 0.074x 4 x Air Moisture Outside (gr/lb) Air Moisture Inside (gr/lb) ( - ) [ ] 2 = 9,396 gr/hr Total 31,781 gr/hr PhEn 602 Spring

62 Conveyor Opening Wall Openings - No Load Open Area (sq.ft.) Air Entry Velocity (fpm) Moisture Outside (gr/lb) Conveyor Openings x x ( - ) x x 60 = g Open Doorways and Holes x x ( - ) x x 60 = g Assume that the product conveyor opening will be equipped with a 2'-tunnel and plastic strips. Those details, combined with 150 fpm exit velocity will eliminate infiltration through the opening Moisture Inside (gr/lb) Air Density (lb/cu.ft.) Minutes Per Hour Moisture Load (gr/hr) Total gr/hr PhEn 602 Spring

63 Moisture In Fresh Air (The Largest Load) Net Fresh Air for Personnel, Exhaust Air Makeup And Room Pressurization Fresh Air Flow Rate (cfm) Moisture Outside (gr/lb) Moisture Control Level (gr/lb) Air Density (lb/cu.ft.) Minutes Per Hour Moisture Load (gr/hr) 600 x ( ) x x 60 = 330,336 PhEn 602 Spring

64 No-Load Elements Open Gas Flame - No Load No open gas flame in the room Wet Surfaces - No Load No wet surfaces in the room [ Gas Burning Rate (cu.ft./hr) Water Vapor Generation (gr/cu.ft.) Moisture Load (gr/hr) x = g Typical Value 650 gr/cu.ft. Wetted Surface Area Latent Heat Transfer Rate Water Surface Vapor Pressure Air Vapor Pressure Grains Per Moisture Load (sq.ft.) (Btu/sq.ft./in.hg.) (in.hg.) (in.hg.) Pound (gr/hr) x x ( - ) ] x 7000 = gr/hr Latent Heat Of Vaporization At The Water Temperature (Btu/lb) Exterior Walls - No Load Exterior wall is equipped with metal foil vapor retarder Wall 1 Wall 2 Surface Area (sq.ft.) Air Infiltration Rate (cu.ft./hr/sq.ft.) Moisture Outside (gr/lb) Moisture Inside (gr/lb) Air Density (lb/cu.ft.) Moisture Load (gr/hr) x x ( - ) x = x x ( - ) x = Total gr/h Cracks - No Load Room will be supplied with excess air to minimize leakage Door Frames Windows Crack Length (ft) Air Infiltration Rate (cu.ft./hr/ft.) Moisture Outside (gr/lb) Moisture Inside (gr/lb) Air Density (lb/cu.ft.) Moisture Load (gr/hr) x x ( - ) x = x x ( - ) x = Ductwork x x ( - ) x = Total gr/h PhEn 602 Spring DH Handbook /6

65 The Load Summary Ventilation air (as in pressurization air) often represents the biggest load Permeation Products Personnel Gas Flame Wet Surfaces Exterior Walls Cracks Door Openings Wall Openings Total Internal Moisture Load , , ,130 Fresh Air 330,336 Moisture in the ventilation air is almost three times larger than the rest of the loads combined PhEn 602 Spring

66 Dehumidifier Performance How dry is the air after it leaves the dehumidifier?... That will depend on: Moisture content of the entering process air Temperature of the entering process air Velocity of the process air through the desiccant Temperature of the entering reactivation air And to a lesser extent: Moisture content of the reactivation air Velocity of the reactivation air through the desiccant Amount of desiccant exposed to the air Wheel rotational speed (eg( eg) Sorption-desorption characteristics of the desiccant PhEn 602 Spring

67 Desiccant Wheel Life Normal life: 3-7 years (but years is not uncommon) Potential failure modes: Desiccant attrition or deliquescence Desiccant deterioration Wheel face clogging Wheel face gouging To extend wheel life: Change or clean filters regularly Check reactivation heaters & airflow Check seal wear Check wheel drive belt & motor Check process air flow PhEn 602 Spring

68 Deliquescence Definition: the process in which a soluble substance picks up water vapor from the air to form a solution. In order for deliquescence to occur, the vapor pressure of the water in the air must be greater than the vapor pressure of the saturated solution. PhEn 602 Spring

69 Key Variables with Hardware Reactivation Air Temperature Process Air Temperature Reactivation Reactivation Heater Process Air Entering Process Air Leaving Process Air Moisture Moisture Leaving Process Process Air Velocity (Unit Size) PhEn 602 Spring

70 Utility Systems Clean Utilities Critical Utilities General Utilities Special Utilities PhEn 602 Spring

71 General Utilities Plant Steam Plant Chilled Water &/or Glycol Compressed Gasses HVAC Waste Water Treatment Electric Plant Water & Drains PhEn 602 Spring

72 Clean Utilities Water Systems Deionized Purified WFI Clean/Pure Steam Clean-in in-place (CIP, SIP, WIP) HVAC Pure Gasses PhEn 602 Spring

73 Clean-in in-place PhEn 602 Spring

74 Clean-in in-place PhEn 602 Spring

75 Special Utilities Biowaste Treatment Bioinactivation PhEn 602 Spring

76 Critical Utilities Can be some or all of clean utilities and may also include other key utilities PhEn 602 Spring

77 Isolators PhEn 602 Spring

78 Isolators PhEn 602 Spring

79 Isolators PhEn 602 Spring