Recovery from Genset gases
The Client : A large beverage manufacturer
near Palakkad, Kerala.
The opportunity : The customer was running
a 750KW genset for 4,000 hours per annum. They were also using low
pressure steam at 3 bar for beverage preparation.
The
solution : The corrosively of sulphur in diesel fumes and soot content
is the main hurdle. Guha Industries planned a once-through steam
boiler, discharging at 3 bar, around a welded "H" type finned tube
exchanger. The flue gas side surface was coated with molten aluminium
to prevent corrosion. The hold up of steam in the exchanger bundle was
deliberately planned to be less than 22 liters to avoid the purview of
the Indian Boiler Regulations.
The savings : At 60% load operation,
reducing the stack from 400oC to 200oC generates
more than 300 kg/h steam. For 4,000 hours operation, this translates
into savings of INRs 840,000/- (US$ 18,000/-). Payback is around 9
months. Saving potential would be more at higher loads.
Recovery of waste heat from kiln gases
The Client : A leading Chemicals factory
in Tamil Nadu
The opportunity : The customer was venting
about 7,500 kg/h of kiln gases at 350 to 400oC. There is a
high heat requirement for drying and evaporation.
The solution : High particulate matter in
the kiln vent was the main hurdle to recovery. A multiclone was put
before the recuperator to knock down the particulates content. A plain
tube, multipass bundle with thermic fluid in the tube side was used to
recover heat from the flue gas. The thermic fluid enters the bundle at
150oC, and leaves at 200oC, knocking down the kiln
gas to 170oC. Thermic fluid was used to replace part of the
heat supplied by the existing steam boiler.
The savings : About INRs 960,000/- (US$
21,000) per annum direct energy savings, and pay-back within a year.
Direct use of bag house after the recovery system; as against using a
dilution air fan to reduce the temperature, followed by larger bag
house.
