Boiler Performance

Boiler performance like efficiency and evaporation ratio reduces with time, due to poor combustion, heat transfer fouling and poor operation and maintenance. Deterioration of fuel quality and water quality also leads to poor performance of boiler. Efficiency testing helps us to find out how far the boiler efficiency drifts away from the best efficiency. Any observed abnormal deviations could therefore be investigated to pinpoint the problem area for necessary corrective action. Hence it is necessary to find out the current level of efficiency for performance evaluation, which is a prerequisite for energy conservation action in industry.

Purpose of the Performance Test

  • To find out the efficiency of the boiler
  • To find out the Evaporation ratio

The purpose of the performance test is to determine actual performance and efficiency of the boiler and compare it with design values or norms. It is an indicator for tracking day-to-day and season-to-season variations in boiler efficiency and energy efficiency improvements.

Boiler efficiency is calculated by below mention method:

  1. The Direct Method
  2. The Indirect Method

Factors Affecting Boiler Performance

The various factors affecting the boiler performance are listed below:

  • Periodical cleaning of boilers
  • Periodical soot blowing
  • Proper water treatment programme and blow down control
  • Draft control
  • Excess air control
  • Percentage loading of boiler
  • Steam generation pressure and temperature
  • Boiler insulation
  • Quality of fuel

All these factors individually/combined, contribute to the performance of the boiler and reflected either in boiler efficiency or evaporation ratio. Based on the results obtained from the testing further improvements have to be carried out for maximizing the performance. The test can be repeated after modification or rectification of the problems and compared with standard norms. Energy auditor should carry out this test as a routine manner once in six months and report to the management for necessary action.

Data Collection For Boiler Performance Assessment

1. Technical Specification of Boiler

  • Boiler ID code and Make
  • Year of Make
  • Boiler capacity rating
  • Type of Boiler
  • Type of fuel used
  • Maximum fuel flow rate
  • Efficiency by GCV
  • Steam generation pressure &superheat temperature
  • Heat transfer area in m2
  • Is there any waste heat recovery device installed
  • Type of draft
  • Chimney height in meter

2. Fuel Analysis Details

  • Fuel Fired
  • GCV of fuel
  • Specific gravity of fuel (Liquid)
  • Bulk density of fuel (Solid
  • Proximate Analysis: Fixed Carbon, Volatile matter, Ash and Moisture percentage in coal
  • Ultimate Analysis: Carbon, Hydrogen, Sulphur, Nitrogen and oxygen percentage in coal

3. Water Analysis

  • Feed water TDS in ppm
  • Blow down TDS in ppm
  • PH of feed water
  • PH of blow down

4. Flue Gas Analysis

  • CO2 % , O2 % , CO %  and Flue gas temperature


Steam Boiler in Thermal Power Plant