This steam boiler project for a UK based textiles manufacturer involved the design, manufacture and retrofit of a bespoke boiler economiser in a horizontal orientation fitted directly onto the boiler flue exhaust flange with inlet / outlet gas side transitions to suit.
The 8,000 kg/hr steam boiler runs at 8 bar g and is fuelled on natural gas.
The boiler economiser cools the boiler flue gases from 240 to 135 °C, thereby preheating boiler feed water from 75 to 109°C, recovering ~300 kW of waste heat and ~425 tonnes/year reduction in CO2 emissions at full boiler load.
This translates to a boiler efficiency uplift of ~6%. The consequent savings in fuel mean the project will pay for itself in just over a year from the date of commission.
The additional back pressure on the burner fan and additional pressure drop across the boiler feed pump was designed to be minimal at full boiler load, hence normal operation of the boiler is unaffected.