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Heat Exchanger Stall

Heat Exchanger Stall. Condensate Return. 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

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Heat Exchanger Stall

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  1. Heat Exchanger Stall

  2. Condensate Return • 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...

  3. A. Condensate Load A= 2000 lb/hr B. Annual hours of operation B= 5000 hrs C. Total Water Cost = (C1+C2) C1. Untreated water and sewage .002 $/gal C2. Water treatment chemicals .003 $/gal C= .005 $/gal D. Make-up water preheating requirements D1. Condensate return temperature 200 °F D2. Make-up water temperature 60 °F D = (D1-D2) x 1.0 BTU/lb / °F D= 140 BTU/ lb E. Steam cost E= 5.00 $/1000 lb F. Savings in water costs (A) x 2000 x (B) 5000 x (C) .005 8.34 lb/gal F= 5,995 $/yr G. Savings for preheating make-up water *(BTU/lb from direct steam injection) (A) 2000 x (B) 5000 x (D) 140 x (E) 5.00 *1000 x 1000 G= 7,000 $/yr H. Cost of steam to run Armstrong Pump Trap 3 x (A) 2000 x (B) 5000 x (E) 5.00 *1000 x 1000 H= 150 $/yr I. Total annual savings = (F+G+H) F. Savings in water costs 5,995 $/yr G. Savings for preheating make-up water +7,000 $/yr H. Cost of steam to run Armstrong Pump Trap - 150 $/yr I= 12,845 $/yr J. Payback of pump purchase Payback = $5,063 (cost of pump package) 12,845 J= .39 yrs

  4. 25 psig Steam Main Modulating Control Valve 0 – 25 psig

  5. Effects of “Stall” • Inadequate condensate drainage • Water hammer • Frozen coils • Corrosion due to Carbonic Acid formation • Poor temperature control • Control valve hunting (system cycling) • Reduction of heat transfer capacity

  6. 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

  7. 25 psig Steam Main Modulating Control Valve 0 – 25 psig

  8. What is the “Stall” Solution? • Use abiggersteam trap ? • Use a vacuum breaker ? • Implement a safety drain ? • Install a Positive-Pressure system ? • Use an electric pump?

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

  10. Product Range • Single pump capacities from 350 lb/hr to 73,000 lb/hr • Flash recovery vessels • Electric condensate pumps

  11. Rescue Cap™ • Fits Spirax Sarco PPC/PPF pumps • Watson McDaniel • Spence • Hoffman PCS • Gestra FPS23 • Johnson • Clark Reliance

  12. Armstrong Stainless Steel Sump Ejector • Replaces standard electric sump pumps (must have high pressure steam available • For steam pits, tunnels and enclosed spaces where ground or rain water can accumulate and requires pumping • Can be used in any application where the water temperature will not exceed 140°F • Great for locations that run underground steam lines where the drip traps are in tunnels or manholes

  13. Armstrong AFT 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)

  14. Packaged Solutions • Standard Packages • Custom Fabrications • ASME Packages • Low Boy Solutions • Vented Systems • Closed-loop Systems • Process Water Packages and more… Closed-loop Low-Boy Receiver Package

  15. Common Industry Applications • Jacketed Kettles • Process Air Heating • Tank Heaters • Shell & Tube Exchangers • Process Media (water, oil, food etc.) • Any steam consuming process heat exchanger utilizing… Modulating Control

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