1. Condensate Management

2. Condensate Return Let’s take a look at a savings analysis...
Hotter boiler feed water temperatures
Minimizes the amount of chemicals required to treat boiler feed water
Eliminates environmental concerns
Minimizes water usage which is critical in some areas
Condensate is a tangible item which can be measured in the form of a savings analysis
Effective return can lower overall costs which can impact profitability
Let’s take a look at a savings analysis...

4. Methods of condensate return
Electric Centrifugal Pumps
Duplex 4300 series installed at a brewery

5. Electric Condensate Pumps (Centrifugal)
Control Panel w/starters
Condensate Inlet
Overflow to drain
Pump and motor assembly
Float switch or alternator
Receiver: Non-pressurized
Suction isolation valve

6. Nema 1 Float Switch for simplex (one pump) packages

7. Nema 1 Mechanical Alternator for duplex (two pumps) packages

8. Nema 12 Control Panel

9. Installation Accessories

10. Advantages Excellent for returning cooler condensate
Standard models 200°F or less
210° floor mounted units available
212° elevated units available
Inexpensive for initial purchase
Low inlet height applications
Can operate against high back pressures without dramatically increasing foot print of package
Most understood method of condensate return

11. Disadvantages Long term repetitive maintenance costs Leaking seals
High temp condensate from blow through traps or leaks in system
Impeller wear – Cavitation
Condensate temperature exceeds NPSH design of pump
Corrosion on electrical components
Requires two trades for installation and repair
Safety for pit areas (flooding)
Must be vented to atmosphere
Units sized 3:1 to allow condensate to cool

12. Disadvantages

14. Mechanical Pumps

15. Pump Trap Operation

16. Pump Trap Operation: Filling
Step 1. During filling, the steam or air inlet and check valve on pumping trap outlet are closed. The vent and check valve on the inlet are open.
Steam/Air In - Closed
Steam/Air Out - Open
Open Check
Valve
Closed Check Valve

17. Pump Trap Operation: Begin Pumping
Steam/Air In - Open
Steam/Air Out - Closed
Check Valve
Closed
Open Check Valve
Step 2. Float Rises with level of condensate until it passes trip point, and then snap action reverses the positions shown in step one.

18. Pump Trap Operation: End Pumping
Step 3. Float is lowered as level of condensate falls until snap action again reverses positions.
Steam/Air - In
Vent Closed
Closed Check
Valve
Open Check Valve

19. Pump Trap Operation: Repeat Filling
Step 4. Steam or air inlet and trap outlet are again closed while vent and condensate inlet are open. Cycle begins anew.
Steam/Air Out - Open
Steam/Air In - Closed
Open Check Valve
Closed Check Valve

20. Mechanical vs. Electrical
No seals, motors or impellers
Eliminates repetitive maintenance
Low maintenance
Few moving parts – advanced mechanism design
Sized for actual condensate load: No need to apply 3:1 safety factor
Hot condensate is no problem
Can be used in closed loop applications
Conserve flash steam (BTU’S)

22. Stall Heat Exchanger Stall
The point at which there is no differential across the trap orifice and condensate starts to back up in to the system

23. Big Problem

24. “Stalled” Heat Exchanger
Steam
Condensate

25. Effects of “Stall” Inadequate condensate drainage Water hammer
Frozen coils or coil leaks
Corrosion due to Carbonic Acid formation
Poor temperature control of product (water, air etc)
Control valve hunting (system cycling)
Reduction of heat transfer capacity

26. Factors Contributing to Stall
Oversized equipment
Conservative fouling factors
Excessive safety factors
Large operating ranges
Back pressure at steam trap discharge
Changes in system parameters

27. Finding “Stall” Modulating Steam Control Where does Stall occur?
Air heating coils
Shell & tube heat exchangers
Plate & frame heat exchangers
Reboilers
Kettles
Any type of heat transfer equipment that has
Modulating Steam Control

28. Mechanical Pump Applications

29. Closed-Loop Systems

30. Big Problem

31. Closed-loop Solution

32. Solution: Closed Loop CO2 evaporator32 32

33. Closed-loop Solution

34. Considerations for closed-loop systems
Receiver sizing
Typically smaller receiver to handle condensate load only
Vent sizing on receiver
Vent line is equalized to receiver and capped with thermostatic air vent or A/VB combination (TAVB)
Location of Receiver
Fill head is important
May or may not require trap down stream of pump
Depends upon max system pressure downstream of the control valve

35. Closed Loop Receiver Sizing

36. Double Duty® Steam Trap/Pump Combination

37. Double Duty® - 4 Double Duty 4 1” x 1” Ductile Iron Pump
Up to 350 lb/hr pumping capacity
Up to 4,000 lb/hr trapping capacity
Integral trap/pump mechanism – single float
Max pressure is 72 psi

38. Double Duty® - 6 Double Duty 6
1-1/2” x 1” 150# flanged Carbon Steel Pump
200 psig rated body
200 psig max operating pressure
Separate pump and trap mechanisms
Up to 4,800 lb/hr pumping capacity
Up to 22,000 lb/hr trapping capacity
External motive/vent seats
Inconel X-750 Springs

39. Double Duty® 12…

40. Double Duty Closed Loop Application
Double Duty® Steam trap/pump combination

41. Double Duty® 12 100% turndown application…

42. Closed System Advantages: No flash steam loss
No need to run long expensive vent lines
No electric pump problems (seals, motors, etc.)
Return condensate hotter
Precautions:
Dedicated pump for a single piece of equipment
Can not use air as motive force

43. Open (vented) System

44. Double Duty Vented System – No Internal Trap Mechanism
Double Duty™ 6 Steam trap/pump combination

45. Open System Advantages: Important notes:
Drain Multiple pieces of equipment
Can use Air or Steam for pump trap operation
Easiest to understand
Important notes:
Modulating steam sources must drain by gravity to receiver inlet (no lifting of condensate)
If installing a Pressure Reducing Valve (PRV), outlet of PRV must be a minimum of 10 feet from pump inlet. If room doesn’t permit, add an accumulator pipe.
Add a vacuum breaker on discharge side of heat exchanger and a thermostatic air vent at high side of exchanger (if not designed to run in vacuum)
Add necessary auxiliary equipment…water level gauges, pressure gauges, receiver overflow, discharge gate valves, drains for receiver/pumps etc

46. Considerations for open systems
Receiver sizing
Receiver must be sized to provide adequate separation of flash steam and condensate
Vent sizing on receiver
Vent line velocity of 3,000 – 4,000 FPM
Location of Receiver
Fill head is important
Prevent flashing in the pump trap
Vent connection on pump too small to vent atmospheric flash steam of any quantity
Could build pressure inside pump body affecting flow into the pump

47. Vented Receiver Sizing (assumes straight up vertical piping)

49. Flash Recovery
Not just a lot of hot air

50. Uses of flash steam… Atmospheric vent condenser Preheat coils
Preheat water/glycol or other media
Preheat coils
Supplement existing lower pressure steam lines
Recover flash to Deaerator
Flash vent condenser on a DPT-3512LBRPI-24-12

51. Flash Steam Calculation
50 psig pressure
0 psig pressure
% of flash steam = – x 100
970.3
% of flash steam = 9.01%
If our condensate load is 2000 lb/hr, the flash steam produced would be:
Flash steam produced = x 2000 or
180 lb/hr of flash steam
267.5 Btu/lb
Btu/lb

52. Flash Steam Graph

53. Flash Steam Savings Calculator
Armstrong Steam-A-ware CD

54. Armstrong VAFT Vertical Flash Vessels
Excellent for providing low velocity flash steam with no water carryover
ASME Sec. VIII U stamped to 150 PSI (other pressures upon request)
Models include:
VAFT-6
VAFT-8
VAFT-12
VAFT-16

55. Armstrong HAFT Horizontal Flash Vessels
Excellent for providing low velocity flash steam with no water carryover
HAFT-4
HAFT-6
HAFT-8
HAFT-10
HAFT-12
HAFT-16
HAFT-2448
HAFT-2472
HAFT-30
ASME Sec. VIII U stamped to 150 PSI (other pressures upon request)
No internal baffling

58. Engineered Solution