System for recovering latent and sensible heat of effluent gases from a

Abstract

System for recovering latent and sensible heat of effluent gases from a cupola for cast iron production or other similar melting installation consequent intermittent operation thereof, for obtaining heat energy or potential electric energy in the form of hot water and/or steam, comprising a thermal unit including an air burner and combustion chamber for burning the effluent gases to form hot combustion gases, two vertical waste heat boilers disposed in series along a flow path downstream of the combustion chamber, the first being a water tube boiler and the second being a fire tube boiler, both having vertical tubes arranged so that the hot gases pass upwardly through the water tubes, thereby licking such tubes, and upon flow reversal thence pass downwardly through the fire tubes, thereby enhancing the self-cleaning thereof, an economizer and optionally a combustion air preheater downstream of the second boiler, and a chimney for the fumes at the end of the flow path, as well as a common external steam separator above the boilers and remote from the flow path for recovering steam from and returning water to each of the boilers, plus a vertical tube superheater connected to the steam separator and including a section inside the top part of the first boiler and/or a section between the two boilers, for supplying superheated steam to an electric energy generating turbine, with recycling thereof as feed water to the thermal unit via the economizer.