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Heat Recovery Unit (HRU)- Small Investment, Big Gains

In cases Mostly Boiler flue gases leave at considerable high temperature taking out valuable heat. Valuable heat can be recovered by installing a simple Heat Recovery Unit (Water Pre-heater). This heat can be utilized to preheat the Boiler Feed Water.
By installing a simple Heat Recovery Unit (HRU), fuel consumption can be typically reduced by 4 % to 6%. Every 5 degree increase in feed-water temperature will give an efficiency improvement of 1%.Heat Recovery Unit (HRU) is a simple shell & tube type Heat ex-changer sized for:

  • The temperature and volume of flue gases
  • Pressure drop across it
  • Fuel used in the boiler
  • Quantity of Heat to be recovered
  • Properly designed HRU has the ability to reduce the fuel requirements of a boiler by transferring heat from the exit flue gases to the feeding water. However flue gases temperature reduction below
  • Sulphur dew-point is not advisable for high sulphur fuels to avoid corrosion & erosion of equipment.

Advantages and Benefits of HRU
          HRU recovers waste heat from flue gases, thereby improving efficiency of the boiler system.
          Helps to the boiler to produce more steam in same cost.
          Heat Feeding water puts less strain on metal as temperature differential is less the Boiler thus helping in extending life of the Boiler.

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2. Short payback period & increased combustion rate
3. In the case of combustion of pulverized coal hot air can be used for drying the coal as well as for burning the coal efficiently
4. All standard fuels and even lower grades of coals can be burnt efficiently with hot air

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