Waste Heat Recovery installations – is it worth it?
In the vast majority of carbon steel boilers built in recent years, the temperature of the exhaust gases discharged to the environment is traditionally kept in the range of 130-340°C, due to the possibility of overcooling the exhaust gases below the sulfur dew point. This relatively high temperature implies high stack losses, which limit the efficiency of gas and oil boilers equipped with economizers to approx. 94%, pulverized coal boilers to 92% and grate boilers to 84%.
The described situation encourages the search for different ways to increase the efficiency of the boiler house by reducing the stack losses. To meet the customers’ expectations, KELVION has launched a series of standardized EcoMi economizers, on the basis of which heat recovery and management installations are built.
Such installations generate significant savings and do not worsen the operating conditions of the boiler installation. They are characterized by several features:
– recovered heat (along with the enthalpy of condensation) is used in boiler devices and for heating purposes (CH or DHW)
– the boiler house efficiency is increased by approx. 10%, thus fuel consumption and CO2 emissions are reduced.
– the WHR installation performs the task of wet deposition of gases (SO2, Cl2, ..) and ash from the exhaust gas.
The results of the exemplary application of the WHR heat recovery installation for steam gas boilers 2x30t/h operating with a load >92% for approx. 8.400 h/year equipped with KELVION economizer batteries are as follows:
– the average efficiency of steam generation increases from 9.90 to 14.32% and is equal to the reduction of natural gas consumption and reduction of CO2 emissions,
– the average reduction of operating costs (fuel purchase) ranges from 480kPLN to 540kPLN / month,
– the investments reimbursement is approx. 6-7 months,
– after cooling the exhaust gas, the condensate complies with the industrial water standards and is returned to the boiler water treatment plant,
– an independent VOC report confirms that the emission standards for natural gas exhaust are maintained.
Last Updated on January 27, 2021 by Karolina Ampulska