SYSTEM FOR RECOVERING HEAT FROM FLUE GAS， CONTROL ARRANGEMENT FOR USE IN SUCH A SYSTEM AND A METHOD PERFORMED BY SUCH A CONTROL ARRANGEMENT

The present invention relates to a heat recovery system10， 11， 12 for recovering heat from flue gas generated by combustion at a biomass plant installation. The heat recovery system10， 11， 12 comprises a flue gas cooler 200 configured to receive flue gas 201 from a combustion and transfer heat from the flue gas 201 to feed water in a heat recovery fluid circuit101. The feed water in the heat recovery fluid circuit101 is taken from and returned to a feed water main system. The feed water main system could be provided with a feed water tank 100to which a heat recovery circuit inlet 112 and a heat recovery circuit outlet are connected. Further， the heat recovery system comprises a waste heat accumulator 300 configured to receive feed water， heated by flue gas 201 in a flue gas cooler 200， and cool by flashing the received feed water in order to generate flash steam， and the heat recovery system10， 11， 12 comprises a control arrangement 533. Further， the present invention also relates to a method performed by the control arrangement for use in recovering heat from flue gas generated by combustion at a bio plant installation.