Boilers

Many companies need to produce heat to satisfy the needs of their production system. This heat is produced in the form of liquid or steam using boilers whose heat source is the combustion of different fuels, such as diesel or natural gas.

The output of equipment that generates heat (boiler, furnace or dryer) provides us with information about the percentage of power available, which is used in the production process, compared with the total power supplied by the fuel used.

This output drops according to the different losses in the transfer of the heat from the boiler to where it is used, together with other factors that have to be monitored to therefore be able to obtain the highest output possible and minimize the cost of the fuels used to produce energy.

ENERGY SAVING AND EFFICIENCY MEASURES

– Combustion control. (6% savings)

Boiler combustion must be optimized so that the greatest amount of energy possible is produced from the fuel, therefore the gases from the boiler flue should be analysed.

The most decisive factor for good combustionis the excess of air until complete combustion is obtained.

According to the flue gas analysis, if the output is low, the ashes and unburned substances should be cleaned out of the furnace and the air intake in the burner should be adjusted.

– Minimizing the purges in the steam boiler. (1% saving)

The steam boilers must be purged to keep the concentration of solids (carbonates dissolved in the water) within certain limits. These increase according to the amount of steam produced. The purge must be the minimum required, because if too much air is let out, more water is consumed and therefore, more energy is lost.

There are different ways to calculate the ideal amount of air that should be purged, which depends on various factors such as the type of boiler, the operating pressure, treatment and quality of the water.

– Recovery of the waste heat from the flue gases .  (Saving between 5% and 20%)

The flue gases that emanate from combustion are extremely hot (above 200ºC); sometimes this heat is used to preheat the combustion air through a recovery system or to preheat the incoming water through an economizer. These two measures can improve the performance of the equipment.

– Minimize losses in walls. (Saving more than 5%)

All the heat produced in the combustion must be used in the production process, which is why we must minimize the existing heat losses in the walls of the furnaces or pipes by insulating them perfectly. A thermographic analysis must evaluate the insulation to determine whether it is in good condition or not.

– Reinject condensates in steam boilers. (Saving more than 5%)

The condensed steam produced beforehand must be returned back into the boiler to make the most of the heat that is still in it and therefore minimize the thermal jump of heat needed to produce steam.

– Changing fuel   (Saving between 10% and 40%)

Changing the fuel for another cheaper fuel is not an energy efficient measure but it is an economic measure. For example, in January, 2012 the cheapest to the most expensive priced fuels to produce the same amount of energy were biomass, natural gas, diesel, propane and electricity.