In any process industry which has steam as a utility for its production, about 20% of energy in the steam
generated is still available as sensible heat in the flash steam and condensate after utilisation in the process.
Pumping the energy available in flash steam and condensate back into the process will help to bring down
the fuel bill and reduce operational costs.
This recovery can be with the help of either an electrical or a steam operated pump.

Condensate Recovery Using Electrical Pumps

In some plants, the condensate from the process is recovered to the feed water tank using an electrical pump. The high temperature condensate from the process is collected in a tank while the flash steam generated from this condensate is vented to the atmosphere. This means that 8-10% of the total energy available in the condensate is lost.

The condensate collected in the tank is then pumped to the feed water tank based on the level in the tank. The temperature of condensate at the outlet of the electrical pump drops to 55-75 deg. C leading to an energy loss of 3-4% of the total energy input in the boiler. With this configuration the feed water temperature is in the range of 50 to 70 deg. C.

So, out of the total 20% energy available in condensate and flash steam, only 8% energy is recovered to the boiler feed water tank and the balance 12% energy is lost to the atmosphere.

Drawbacks of using an electrical pump for condensate recovery

The drawbacks in this method can broadly be classified under energy loss, impact to environment, safety concerns and reliability. 

Energy loss 

-  Low feed water temperature 
-  Low condensate return temperature 
-  Loss of flash steam 
-  Increased boiler blowdown 
-  Increased fuel bill 

Environmental impact 

-  More make-up water required 
-  Increased chemical treatment 
-  Electrical power consumption for pumping condensate 
-  High carbon footprint 

Safety concerns 

-  Hazards to life and equipment due to venting, dry running and cavitation 

Reliability 

-  Subject to power fluctuations and failures 
-  Frequent maintenance of electrical pump and level control system

Condensate Recovery Using Steam Operated Pumps

Steam operated pumps are positive displacement mechanical pumps designed to avoid the issues commonly associated with condensate recovery using electrical pumps. They are completely skid mounted solutions that can pump condensate at a temperature range of 95-100 deg. C. eliminating the need of chemical treatment of feed water. Overall cost of operation is much lower as compared to centrifugal / electrically operated pumps.

The Ideal Solution: Forbes Marshall FlashJet^TM Steam Operated Pump for 100% flash steam and condensate recovery

The Forbes Marshall FlashJet ^TM Pump is a completely integrated solution for complete recovtery of flash steam and condensate in closed loop. With the FlashJet pump, the high temperature condensate at 103-106 deg C, and flash steam generated therefrom, is completely recovered to the feed water tank, ensuring that the total energy available after utilisation in the process, i.e~ 20% is returned to the feed water tank.

With complete flash steam and condensate recovery to the feed water tank, the temperature of feed water is maintained at 90 - 95 deg. C, with the help of a de-aerator and recirculation pump.

Energy efficiency of the system can further be enhanced by :

-  Monitoring the steam consumption in the process quantity of condensate recovered to the feed water tank and
-  Monitoring the health of the steam traps using a trap monitoring system 

Benefits of recovering condensate using the Forbes Marshall FlashJet^TM Steam Operated Pump 

Energy Savings 

- 100% recovery of flash steam and condensate at equipment level 
-  Higher condensate recovery temperature 
-  Complete flash steam recovery 
-  High feed water temperature 
-  Reduced boiler blowdown 
-  Lower fuel bill 

Environmental impact 

-  Less make-up water required 
-  No chemical treatment of feed water 
-  No electricity required for pumping condensate 
-  Lower carbon footprint 

Safety 

-  Safe utilisation of flash steam in feed water tank 
-  No danger of cavitation in equipment  

Reliability 

-  Low maintenance, high uptime