Application of Recuperator for Waste Heat Recovery From Exhaust Flue Gas in Hot Water Boiler in the Central Heating Plant

Abstract

In general, the outgoing exhaust gasses are released to atmosphere at over temperature of the dew point of water vapor in waste gases. It is well known that recovering a portion of the waste heat enhances the efficiency of boilers and provides fuel savings. In this study, the potential of recovering waste heat emitted by the hot water boiler chimney in a central heating plant of a selected university was investigated. Energy losses were calculated for six months that the central heating system was in full-load operation. As a result of the calculation, it was determined that recovery of the waste heat can be employed as a combustion air preheater by means of a recuperator. It was stated that 53,768 m 3 of natural gas savings per year (44.86 TOE/year) can be achieved with the suggested system.

Energy Efficiency and Environmental Benefits of Waste Heat Recovery Technologies in Fishmeal Production Plants: A Case Study in Vietnam

“…Several studies in different industries have demonstrated the potential benefits of WHR technologies in improving energy efficiency and reducing environmental impacts. For example, a study conducted in a biscuit factory in Turkey reported energy savings of 27.13 tons of CO 2 emissions per year using economizers to recover waste heat from their boiler [26]. Similarly, installing WHR technology in industrial boilers in Malaysia's paper and pulp industries achieved savings of 2150 tons of CO 2 per year [27], comparable to the observed reduction of 866.70 tons of CO 2 emissions per year in the KHS factory.…”

Opportunities of waste heat recovery from various sources: Review of technologies and implementation

“…Thus, the energies of the flue gas without ( ) and with ( ) heat recovery are expressed, respectively, as given in Eqs. (5) , (6) [ 147 ]: where is the mass flow rate of the flue gas (kg/h), is the specific enthalpy at the flue gas temperature (kJ/kg), is the specific enthalpy of the flue gas at the ambient temperature (kJ/kg), and is the specific enthalpy of the flue gas after heat recovery (kJ/kg). Thus, the energy saved (kJ/h) by using WHR is expressed as: …”

“…The expression for the accrued savings on fuel in kg/h is obtained from Karanfil et al [ 147 ]: where is the lower heating value of the fuel (kJ/kg), and is efficiency of the heating unit.…”