Monday, December 18, 2017

Energy Conservation Tips on Paper IndustryPrint


Paper Machine:

  • Re-use or improve the rate of circulation of white water to reduce the wasteful discharge, which leads to reduction of new water usage.
  • Discharge of white water means discharge of heat. Maintenance of high temperature system by effective circulation of white water will improve the yield rate.
  • Improve dewatering rate which will reduce the amount of steam used for drying.
  • Keep dryer surface clean by effective use of the doctor blade thereby ensuring high heat conductivity.

 

Pulping Process:

  • Periodically clean the heat exchangers of liquor to increase the cooking liquor temperature thus the temperature inside the digester.
  • Periodically clean the heat exchangers of uncondensed hot gases from digester to recover heat as hot water.
  • Install de-inking system and recycle the used paper for paper board, newspapers, writing paper and toilet paper. Energy consumption in pulping the waste paper is much less as compared to wood pulping.

 

Maintenance:

  • Strictly follow preventive maintenance to prevent
  • Electric failure
  • Steam supply failure
  • Paper breaking
  • Preventing blanket and wire net from being contaminated.

and to

  • Acceleration of press dewatering.
  • Acceleration of evaporation in dryer.
  • Improve performance of impurity removing equipments to avoid paper breakage.

 

Fuel Oil Handling and Operation:

  • For efficient combustion pre-heat the oil to have temp between 1050-1100C at burner tip and optimize air to fuel ratio.
  • To stop abrasive particles FO filtration system should have filter mesh sizes as follows.

a. Between Lorry & main storage tank-mesh size 10
b. Between service tank & pre-heater- mesh size 40
c. Between pre-heater and burner- mesh size 100

  • Provide water draining facility and regularly drain water. This reduces sludge formation and other problems like erosion of burners and damage to the refractories.
  • It is preferred to have parallel FO pumps of smaller capacity than one pump of larger capacity to avoid unnecessary re-circulation of huge quantity of FO.
  • Replace electric preheaters with steam coil preheater for DG set fuel since steam is cheaper source than electricity and is available at site.

 

Boiler and Accessories:

  • Control excess air with oxygen at 3.0 to 4% level in flue gas.
  • Air flow to fuel feed rate should be controlled for oxygen level around 3.0 % oxygen in flue gases.
  • Normally flue gas temperature is beyond 4000C. To recover waste heat install/replace recuperator of required capacity and pre-heat the air.
  • Maintain TDS in boiler. If required install an automatic blowdown system.
  • Maintain stack temperature in the range of 1800-2000 C by oil pressure adjustment, burner cleaning, filtering fuel, soot & scale removal and excess air to 3 %.

 

Condensate Recovery:

  • Improve the condensate recovery and monitor continuously so as to raise the feed water temperature up to 750-800 C and reduce fresh DM water requirement.

 

Insulation

  • Improve insulation and cladding of DG sets exhaust
  • Insulate Flanges & valves to minimize heat loss. Insulation is to be of boxed type for maintenance ease.
  • Steam line, boiler feed water lines to be checked periodically and damaged insulation to be repaired immediately.
  • Improve insulation if the surface temperature exceeds 600C. Ensure that proper insulating material and thickness is provided for proper insulation.
  • Insulate the boiler feed water tank after implementing condensate recovery.(if not existing)
  • Arrange or ask for Industrial training programme in your cluster once a year.

 

Steam Trap

  • Maintenance of steam traps to be carried out regularly. Condensate to be sent back to boilers.

 

Coal

  • Prepare a hard ground for stacking coal and avoid carpet loss.
  • Monitor moisture content and maintain as recommended by boiler manufacturer.

 

Compressed Air:

  • Reduce compressed air pressure from 8 Kg/Cm2 to 7.0 Kg/Cm2 where ever possible to conserve energy, when required pressure at usage point is 6.0 Kg/Cm2
  • Stop use of compressed air for floor cleaning.
  • Check for compressed air leakage.

 

DG Sets Operation and Maintenance:

  • Improve SFC of the DG sets
  • DG sets flue gas temperature is more than 4500C install waste heat recovery boilers on DG sets to generate additional steam & pre heat fuel oil
  • Improve specific electricity generation by loading in excess of 60% and upto 80%

 

Motors:

  • ¨ Replace underloaded / overloaded motors with proper size motors.

 

Pumps:

  • Replace underloaded pumps with new pumps of proper size.

 

Illumination:

  • Rationalise lighting in identified areas i.e. remove excess lighting in identified areas. Also relocate lighting if necessary.