Boiler and Steam Distribution Maintenance.

1. Cleaning.

Cleaning of burner components and heat transfer surfaces will be required in order to maintain efficient operation.


In the case of burners this is especially important for oil-fired types. The production of a thin even film of oil is only possible in rotating cup types if the sharp edge of the cup is intact and not disrupted by deposits. Similarly pressure jet types require clean nozzles.


Heat transfer surfaces can become coated on the fire-side, in either case reducing the heat transfer rate through the insulating effect of deposits. This is evidenced by a higher than usual flue gas temperature. Apart from periodic cleaning during shutdown and soot-blowing, fuel additives are sometimes used to reduce the problem on the fire-side. Water treatment controls water-side effects.

2. Insulation.

Maintaining the integrity of insulation around boiler shells, steam and hot water pipes and condensate return system is important in the overall efficiency of the whole operation. In particular the outer cladding which protects the insulation from damage and the weather should be inspected and repaired where faulty. Water entering porous insulation leaks or from the atmosphere will negate the effects of insulation.

3. Leakage.

At certain sites within the combustion gas path, the pressure may be bellow atmospheric giving the possibility of air leakage into the boiler. This creates a reduction of efficiency through upsetting the control of the fuel to air ratio.


Steam and hot water leakage from pipes creates several problems. There is a hazard to staff from high temperature steam escaping into the atmosphere and from water on the floor, energy is wasted (see table below), treated (and thus expensive) water is lost and insulation can be damaged.


In the case of oil installations, the prevention of any form leakage is essential for safety and ground pollution reasons as well as for simple fuel loss. Tanks should always be contained in a bund wall designed to contain any loss.

4. Examples of fuel penalty of typical leaks in a 7 bar g steam system.

Leak size mm diameter    Steam loss tonne/year      Fuel used tonne/year
             0.80                                12.00                                0.80
             1.60                                48.00                                3.40
             3.20                              180.00                              12.60
             6.40                              732.00                              51.20
             9.50                           1.680.00                            118.00




Source: European Brewery Convention-Manual of Good Practice: Brewery Utilities.