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

Claim 2

System for recovering latent and sensible heat of effluent gases from a cupola for cast iron production or from 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, which comprises a thermal unit and a superheater for producing superheated steam capable of converting the heat energy into electric energy, the thermal unit including a combustion air burner and a combustion chamber arranged for burning such effluent gases with combustion air to form hot combustion gases therefrom, two vertical waste heat boilers arranged for independent heat recovery operation and disposed in series along a flow path successively downstream of the burner and combustion chamber for receiving in turn the hot combustion gases from the combustion chamber, the first of said boilers being of the water tube type having vertically arranged water tubes and the second of said boilers being of the fire tube type having vertically arranged fire tubes, and the flow path having a first vertical flow portion containing such water tubes, a second vertical flow portion containing such fire tubes and an intermediate upper interconnecting transitional reverse flow portion between the first and second vertical flow portions for thereby permitting the hot combustion gases flowing along the flow path through the two boilers to flow in an upward direction from bottom to top in the water tube boiler so as to lick the water tubes thereof, thence through the upper interconnecting reverse flow portion and in turn to flow in a downward direction from top to bottom in the fire tube boiler so as to enhance the self-cleaning of the fire tubes thereof, and a common external steam separator installed above the two boilers and in remote spaced relation to the flow path and operatively respectively connected to the two boilers for correspondingly receiving steam therefrom and returning water thereto.

Claim 3

System of claim 1, wherein the fire tubes of the fire tube boiler are provided with a smooth internal surface.

Claim 4

System of claim 1, wherein the fire tubes of the fire tube boiler are provided with a non-smooth internal surface capable of being cleaned by blowing or mechanical means.

Claim 5

System of claim 3, wherein the fire tubes of the fire tube boiler are provided with a finned internal surface capable of being cleaned by blowing or mechanical means.

Claim 6

System of claim 1, wherein the water tube boiler is arranged to function by radiation and convection heat transfer, being provided with external round manifolds for this purpose, including a first such manifold disposed to distribute water in the vertically arranged water tubes along one or more peripheral circumferences and a second such manifolds thereabove and disposed to collect the resulting water tube boiler produced mixture of steam and water at the top of the water tubes and convey it to the steam separator, such arrangement being disposed such as to leave free the central portion of the lower portion of the first vertical flow portion containing the water tubes of the water tube boiler and thereby to form in such lower portion an extension to the combustion chamber for improving the combustion efficiency thereof and also to provide water tube heat transfer surfaces which are consequently only exposed to fouling to a limited degree.

Claim 7

System of claim 5, wherein the superheater is in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes forming a central superheater section separately installed inside the top portion of the water tube boiler at the corresponding central portion of the upper portion of the first vertical flow portion of the flow path, for permitting primarily convective heat transfer and secondarily radiant heat transfer to the superheater tubes thereat.

Claim 8

System of claim 5, wherein the superheater is in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes forming an intermediate superheater section separately installed between the two waste heat boilers in the intermediate upper interconnecting transitional reverse flow portion of the flow path, for permitting heat transfer to the superheater tubes thereat.

Claim 9

System of claim 5, wherein the superheater is in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes forming two series connected sections, including a first central superheater section separately installed inside the top portion of the water tube boiler at the corresponding central portion of the upper portion of the first vertical flow portion of the flow path, for permitting primarily convective heat transfer and secondarily radiant heat transfer to the central section superheater tubes thereat, and a second intermediate superheater section separately installed between the two waste heat boilers in the intermediate upper interconnecting transitional reverse flow portion of the flow path, for permitting heat transfer to the intermediate superheater tubes thereat.

Claim 10

System of claim 1, wherein the superheater is in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes forming an intermediate superheater section separately installed between the two waste heat boilers in the intermediate upper interconnecting transitional reverse flow portion of the flow path, for permitting heat transfer to the superheater tubes thereat.

Claim 11

System of claim 1, wherein the superheater is in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes separately installed in the flow path upstream of the fire tube boiler, and the thermal unit further includes an economizer arranged in the second vertical flow portion of the flow path downstream of the fire tube boiler, so that the flow therethrough is downwardly from top to bottom for permitting relative self-cleaning thereof and at the same time for limiting the deposition thereat of dusts flowing therethrough from the fire tube boiler, and a chimney downstream of the economizer for discharge of fumes from the flow path.

Claim 12

System of claim 10, wherein a preheater for preheating the combustion air for the burner is arranged in the second vertical flow portion of the flow path downstream of the economizer and upstream of the chimney, so that the flow therethrough is downwardly from top to bottom for permitting relative self-cleaning thereof and at the same time for limiting deposition thereat of dusts flowing downwardly therethrough from the fire tube boiler and economizer.

Claim 13

System of claim 11, wherein the economizer and preheater are arranged in staggered relation in the second vertical flow portion of the flow path for enhancing the relative self-cleaning thereof and at the same time for enhancing the limiting of the deposition thereat of dusts flowing downwardly therethrough from the fire tube boiler.

Claim 14

System of claim 10, wherein an electric energy converter is provided for converting the heat energy of the superheated steam into electric energy when so desired, including a steam turbine arranged for receiving superheated steam from the superheater, an alternator operatively connected with the turbine for generating electric energy, and a steam condenser and a degasser operatively connected with the turbine for receiving spent steam therefrom for condensing and recovering the water content thereof and operatively connected with the economizer and steam separator for passing the condensed water content through the economizer and then recycling the same to the thermal unit via the steam separator.

Claim 15

System for recovering latent and sensible heat of effluent gases from a cupola for cast iron production or from 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, which comprises a thermal unit and superheater for producing superheated steam capable of converting the heat energy into electric energy, the thermal unit including a combustion air burner and a combustion chamber arranged for burning such effluent gases with combustion air to form hot combustion gases therefrom, two vertical waste heat boilers arranged for independent heat recovery operation and disposed in series along a flow path successively downstream of the burner and combustion chamber for receiving in turn the hot combustion gases from the combustion chamber, the first of said boilers being of the water tube type having vertically arranged water tubes and the second of said boilers being of the fire tube type having vertically arranged fire tubes, and the flow path having a first vertical flow portion containing such water tubes, a second vertical flow portion containing such fire tubes and an intermediate upper interconnecting transitional reverse flow portion between the first and second vertical flow portions for thereby permitting the hot combustion gases flowing along the flow path through the two boilers to flow in an upward direction from bottom to top in the water tube boiler so as to lick the water tubes thereof, thence through the upper intermediate reverse flow portion and in turn to flow in the downward direction from top to bottom in the fire tube boiler so as to enhance the self-cleaning of the fire tubes thereof, and a common external steam separator installed above the two burners and in remote spaced relation to the flow path and operatively respectively connected to the two boilers for correspondingly receiving steam therefrom and returning water thereto, the superheater being in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes installed in the flow path upstream of the fire tube boiler.

Claim 16

System for recovering latent and sensible heat of effluent gases from a cupola for cast iron production or from 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, which comprises a thermal unit and superheater for producing superheated steam capable of converting the heat energy into electric energy, the thermal unit including a combustion air burner and a combustion chamber arranged for burning such effluent gases with combustion air to form hot combustion gases therefrom, two vertical waste heat boilers arranged for independent heat recovery operation and disposed in series along a flow path successively downstream of the burner and combustion chamber for receiving in turn the hot combustion gases from the combustion chamber, the first of said boilers being of the water tube type having vertically arranged water tubes and the second of said boilers being of the fire tube type having vertically arranged fire tubes, and the flow path having a first vertical flow portion containing such water tubes, a second vertical flow portion containing such fire tubes and an intermediate upper interconnecting transitional reverse flow portion between the first and second vertical flow portions for thereby permitting the hot combustion gases flowing along the flow path through the two boilers to flow in an upward direction from bottom to top in the water tube boiler so as to lick the water tubes thereof, thence through the upper intermediate reverse flow portion and in turn to flow in the downward direction from top to bottom in the fire tube boiler so as to enhance the self-cleaning of the fire tubes thereof, and a common external steam separator installed above the two burners and in remote spaced relation to the flow path and operatively respectively connected to the two boilers for correspondingly receiving steam therefrom and returning water thereto, the superheater being in the form of a steam superheater operatively connected to the steam separator and having vertically arranged superheater tubes installed in the flow path upstream of the fire tube boiler.