FR2996470A1 - Device for absorbing heat from solid product i.e. metal product, in steel industry, has heat recovery unit, spacer unit, and heat conductive derivative element that is placed in contact with surface of solid product i.e. metal product - Google Patents

Abstract

The device has a heat recovery unit (30), a spacer unit, and a heat conductive derivative element that is arranged such that the derivative element is placed in contact with a surface of a solid product i.e. metal product. The heat recovery unit includes a heat transfer fluid such as gas and/or liquid, and the spacer unit is arranged in contact with the heat conductive derivative element. The derivative element is arranged with a base plate (31) on which the solid product rests upon. The spacer unit is arranged for circulation of the heat transfer fluid. An independent claim is also included for a housing.

Description

The present invention relates to the field of cooling of solid products and their cooling kinetics. STATE OF THE ART Many industrial processes involve steps for cooling solid products, for example in the field of steel making at the hot rolling outlet. The most common method of cooling involves the natural convection heat dissipation between the product to be cooled and the ambient air. This method is relatively long and does not control the cooling rate, particularly because of the variability of the parameters related to the ambient air (temperature, humidity, pressure, wind).

However, uncontrolled cooling can adversely affect the product, for example by non-uniform cooling between the surface and the core of the product which creates a temperature gradient that can cause internal stresses in the product. Such tensions can lead to greater fragility of iron and steel products. Cooling speed control and off-heat removal devices have been developed to address this problem. In such devices, the solid products to be cooled pass through a cooling chamber in whose walls a coolant liquid circulates. The heat generated by the products is transmitted by radiation to the walls of the enclosure and then captured and discharged by the coolant circulating in the walls. The thermodynamic components of the heat transfer liquid (pressure, flow, temperature) make it possible to influence the rate of cooling of the products. It is also known to reduce the cooling rate by injecting steam into the cooling chamber, which has the effect of reducing the amount of heat emitted by radiation. Effective for high temperatures, the radiation heat exchange efficiency is rapidly degraded for low and medium temperatures (below 600 ° C) and makes it necessary to extend the residence time of the products in the cooling chamber. bring them to temperatures from which the cooling rate has no impact on the product.

In the interest of energy efficiency, this heat can usefully be recovered and upgraded to be reinjected into other heat-consuming operations or transformed into electricity. As such, there are known systems using a gas blown on solid products circulating in a cooling chamber. The gas circulates in the cooling chamber, usually by means of a fan, and captures the heat of the solid products by convection. The thus heated gas is directed to a series of heat exchangers for heating water to generate steam which is then directed to an expansion turbine. Convective exchanges require a gas circulation device that consumes a lot of energy and reduces the efficiency of the process. These exchanges also require an extended residence time of the rooms in the enclosure because of a low heat exchange coefficient between the circulating gas and the solid product. Thus, the existing devices for capturing the heat emitted by solid products until they reach a temperature close to ambient temperature result in prolonged residence times of the products in the cooling chamber which are often higher than the rates manufacturing of products. The cooling of the products therefore represents a critical point in the manufacturing process. These constraints make it necessary to have several cooling chambers and prevent the entire cooling of the products manufactured from being controlled.

OBJECT OF THE INVENTION An object of the invention is to improve the control of the cooling conditions of solid products and their kinetics. SUMMARY OF THE INVENTION For this purpose, according to the invention, provision is made for a device for collecting the heat emitted by a solid product in a cooling chamber, the device comprising means for heat recovery by conduction, these means comprising at least one drainage element, thermally conductive, arranged to be brought into contact with at least one surface of the solid product. Conduction makes it possible to obtain higher heat exchange coefficients than those of the prior art, especially for average temperatures of the order of 600 ° C. The residence times of the products to be cooled, until they reach a temperature close to ambient temperature, are therefore reduced. The drainage element may be a solid element, for example unitary or in the form of a set of solids divided as a powder or grains, an elastically deformable product, or a viscous liquid product. It should be noted that the greater the area of the drainage element in contact with the product, the faster the cooling. The invention also relates to such a device wherein the conductive heat recovery means comprise a coolant circulating in a thermally conductive conduit in contact with the drainage element. This fluid comprises a gas or a liquid and can supply an expansion turbine. This system then makes it possible to transform the heat of the solid product to be cooled into electrical energy.

The invention also relates to such a device wherein the coolant feeds a heating circuit. The heat of the solid product to be cooled can then be used for heat-consuming operations.

The invention also relates to a device in which the drainage element comprises a sole on which the solid product rests. The hearth may also be provided with at least one thermally conductive conduit for circulating a heat transfer fluid.

The invention also relates to a similar device in which the heat recovery means also comprises a thermally conductive structure in contact with an upper surface of the solid product and a device comprising at least one thermal drainage element having a divided surface of contact with the solid product. The invention also relates to such a device, also comprising radiative heat recovery means and a similar device wherein the radiative heat recovery means are associated, by a heat transfer link, to a circulation duct for a coolant. The invention also relates to such a device, wherein the solid product is running in the cooling chamber. The solid product may be a metal product. The invention also comprises a cooling chamber for a solid product in scrolling successively comprising, in the direction of travel of the solid product in the cooling chamber: radiative heat recovery means; a conductive heat recovery device and radiation heat recovery means; a device for heat recovery by conduction.

A device for collecting heat emitted by solid products is thus obtained which makes it possible to adjust the cooling parameters of the solid products and which makes it possible to recover the heat emitted by these, for example in the form of a hot source. for other operations or in the form of electricity. Conduction makes it possible to recover the heat more quickly at medium and low temperatures and thus to accelerate the cooling of the parts. Other features and advantages will become apparent on reading the following description of particular non-limiting embodiments of the invention. BRIEF DESCRIPTION OF THE FIGURES Reference will be made to the accompanying drawings, in which: FIG. 1 is a schematic overall view in longitudinal section along a vertical plane I-I of a first embodiment of the device according to the invention; - Figure 2 is a schematic overall view in longitudinal section along a horizontal plane II-II of the embodiment of Figure 1; - Figure 3 is a schematic cross-sectional view along a vertical plane III-III of the embodiment of Figure 1; FIG. 4 is a diagrammatic cross-sectional view along a vertical plane IV-IV of the embodiment of FIG. 1; - Figure 5 is a schematic cross-sectional view along a vertical plane V-V of the embodiment of Figure 1; FIG. 6 is a diagrammatic overall perspective view partially broken away of the embodiment of FIG. 1; Fig. 7 is a schematic view of the coolant circuit of the embodiment of Fig. 1; - Figure 8 is a schematic overall view in longitudinal section along a vertical plane VIII-VIII of a second embodiment of the device according to the invention; - Figure 9 is a schematic overall view in longitudinal section along a horizontal plane IX-IX of the embodiment of Figure 8; FIG. 10 is a schematic cross-sectional view along a vertical plane XX of the embodiment of FIG. 8. DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION With reference to FIGS. 1 to 6, the device complies with the invention comprises a cooling chamber, generally designated 1, delimiting an interior volume 2. The chamber 1 is optionally arranged to thermally isolate the interior volume 2 of the ambient air. This enclosure 1 is substantially parallelepipedal and comprises, on two opposite faces, a loading inlet 3 and an outlet 4 between which metal slabs 5 are moving in a longitudinal direction of scrolling oriented from the loading inlet 3 to the outlet 4 and shown by an arrow in Figure 1. The inlet 3 and the outlet 4 are optionally provided with thermally insulating doors. The slabs 5 enter the cooling chamber 1 at a temperature generally between 900 ° C. and 1400 ° C. and rest here on two supports, shown schematically in 6.1 and 6.2, belonging to a conveyor, schematized at 6, which extends from the inlet 3 to the outlet 4 of the cooling chamber 1. The supports of the conveyor are for example spars extending parallel to the slabs and at least some of which are movable in a vertical plane at a pilgrim's pace to move the slabs. The conveyor may be of another type and, for example, the supports, of known type, are rollers spaced in such a way that each slab rests on at least two rollers. These rollers can be motorized or not, the slabs being pushed by each other in the latter case. In another variant, the supports, of known type, are slides on which the slabs are resting which are pushed by each other. The internal volume 2 of the cooling chamber 1 comprises heat recovery means implanted above and below the supports 6.1, 6.2 and thus slabs 5 scrolling. These heat recovery means are of two types: radiative heat recovery means 20 and conductive heat recovery means 30. The cooling chamber 1 comprises three successive cooling zones A, B and C according to FIG. 5, the first zone A comprises radiative heat recovery means 20 implanted above and below the supports 6.1, 6.2 slabs 5 scrolling. With reference to FIG. 4, the second zone B comprises radiative heat recovery means 20 implanted above the supports 6.1, 6.2 and thus moving slabs 5 and conductive heat recovery means 30 implanted in the region. below the supports 6.1, 6.2 and thus slabs 5 scrolling. Finally, with reference to FIG. 5, the last zone C comprises conductive heat recovery means 30 implanted above and below the supports 6.1, 6.2 and thus slabs 5 running.

The radiation and conduction heat recovery means 30 are now detailed with reference to FIGS. 1 to 6. The radiation heat recovery means 20 comprise ducts 21 made of thermally conductive material. Thermally conductive means a material whose thermal conductivity is here between 5 and 500 W / mK. These thermally conductive ducts 21 are arranged in the internal volume 2 of the enclosure 1 and extend between the two longitudinal walls of the cooling chamber 1. The ends of each of these thermally conductive ducts 21 are connected to a control circuit. radiant heat capture 50 in which circulates a heat transfer fluid 22 through inlet 23 and outlet 24 taps which pass through the longitudinal walls of the cooling chamber 1. The thermally conductive conduits 21 implanted above the supports 6.1 , 6.2 and thus slabs 5 are suspended from the ceiling of the cooling chamber 1 by supports 25 and the thermally conductive conduits 21 implanted under the supports 6.1, 6.2 rest on the floor of the cooling chamber 1 via supports 26. The means for heat recovery by conduction 30 comprise a solid drainage element, made of a thermally conductive material, here an the conductive 31 steel, placed on the floor of the cooling chamber 1 and wherein extend in a direction transverse to the running direction of the slabs 5, thermally conductive conduits 32 in contact with the conductive sole 31 and in which circulates a heat transfer fluid 33. The ends of each of these ducts 32 are connected to a conduction heat sensing circuit 100 through inlet and outlet taps 34 which pass through the longitudinal walls of the enclosure 1. The two supports 6.1 and 6.2 of the conveyor 6 extend in grooves 36.1 and 36.2 formed in the conductive sole 31. The sole thus arranged is brought into contact with the lower surface of the slabs 5 during the movement of these slats. ci in the cooling chamber 1. The supports are here movable, by their movement in pilgrim steps, between a position slightly projecting from the sole in which the slabs are slightly above the sole and a retracted position in the sole, the slabs then resting on the sole. The cooling chamber 1 also comprises heat recovery means by conduction in the form of a second thermally conductive drainage element 37 implanted above the slabs 5, in the upper part of the cooling chamber 1. This element drainage device 37 has a structure identical to that of the conductive sole 31, and also comprises thermally conductive conduits 32 for circulating the coolant 33, but is in contact with an upper face of the slab 5. With reference to FIGS. 1 to 7 , the radiation heat sensing circuit 50 and the conduction heat sensing circuit 100 are now detailed. Although, in the figures, only the heat capture circuits located below the moving slabs 5 are shown, the inlet 23 and outlet 24 connections of the radiative heat capture means located above the slabs 5 in scrolling are also connected to the radiation heat capture circuit 50 and the input and outlet tappings 34 and 35 of the conduction heat sensing means located above the moving slabs 5 are also connected to the sensing circuit of FIG. radiation heat 100 The radiation heat sensing circuit 50 is a closed circuit which comprises a duct 51 to which fluid flow pump 52 is fluidly connected in the direction of flow of the fluid represented in the duct 51 by arrows. coolant 22, a supply feeder 53 of the inlet connections 23, a manifold 54, outlet connections 24 and a heat exchanger 55. The pump 52 thus supplying heat transfer fluid 22, the thermally conductive conduits 21 located in the cooling chamber 1. During its passage through the thermally conductive conduits 21, the coolant 22 stores radiation heat emitted by the slabs 5 in scrolling and exits through the outlet taps 24 in the manifold 54. The coolant 22-here pure water- can undergo during its warming phase changes total or partial and then include a gas (water vapor) and a fluid (water) or comprise only one of these two phases.

The coolant 22 is then directed to the heat exchanger 55 in which it transfers the stored radiation heat to a heating circuit 60. At the outlet of the heat exchanger 55, the coolant 22 returns to the inlet of the heat exchanger 55. the pump 52.

The conductive heat capture circuit 100 is a closed circuit which comprises a duct 101 to which are connected fluidically, in the direction of flow of the fluid represented by arrows in the duct 101, a pump 102 for circulating the coolant 33, a supply feeder 103 of the inlet taps 34, a manifold 104 of the outlet taps 35, an expansion turbine 105 as well as a condenser 106. The pump 102 thus supplies heat transfer fluid 33, the thermally conductive ducts 32 extending in the conductive sole 31 and the drainage means 37. During its passage in these conduits 32, the heat transfer fluid 33 stores heat conduction and spring heated by the outlet tappings 35 in the manifold 104. The heat transfer fluid In this case pure water may undergo total or partial phase changes during its warming, and then include or not include gas (water vapor) and fluid (water). only one of these two phases. The coolant 33 is then directed to the expansion turbine 105 which converts the vaporized portion of the heat transfer fluid 33 into mechanical work and electricity when said turbine drives an electric machine such as an alternator. At the outlet of the expansion turbine 105, the coolant 33 is directed to the condenser 106 before passing through the pump 102. In operation, the device drives the slabs 5 through the cooling chamber 1 thanks to the carriers 6.1 and 6.2 of the conveyor 6. By passing through the cooling zones A and B of the enclosure 1, the slabs 5 yield part of their heat by radiation to the thermally conductive conduits 21 implanted above and below the slabs 5 in scrolling for the zone A and above the slabs 5 running for the zone B. The thermally conductive conduits 21 transfer this heat to the coolant 22 which passes therethrough and which then gives it to the heating circuit 60 in the exchanger 55. At the outlet of zone A the slabs 5 - whose temperature is substantially lowered by a temperature generally between 900 ° C. and 1400 ° C. taken between 400 and 800 ° C - pass in the cooling zone B in which they rest on a conductive sole 31 which captures their heat by conduction and transfers it to the coolant 33 circulating in the conduits 32 passing through the conductive sole 31. In zone C, the upper face of the slabs 5 - which still rest on the conductive sole 31 - comes into contact with the drainage element 37 which also captures their heat by conduction and transmits it to the coolant 33 via the conduits 32 therethrough . When they reach the outlet 4 of the cooling chamber 1, the slabs 5 have transferred most of their heat to the heat recovery means 20 and 30. During their passage through the cooling chamber 1, the slabs 5 have heated the heat transfer fluids 22 and 33 of the radiation heat capture circuit 50 and the conductive heat capture circuit 100. The fluid 22 then transfers its heat in the exchanger 55 to a heating circuit 60 before return to the pump 52 when the fluid 33 sees its gaseous phase relaxed in the turbine 105 generating electricity. The fluid 33 then passes into a condenser 106 before returning to the circulation pump 102. The conditions in which the cooling of the slabs 5 running in the cooling chamber 1 is carried out (such as, for example, the cooling rate) are in particular controlled by the adjustment of the following parameters: respective lengths of the cooling zones A, B and C; speed of movement of the slabs 5; -nature and thermodynamic parameters (among which temperature, flow rate and pressure) of heat transfer fluids 22 and 33. This gives a device capable of controlling the cooling of solid products to control their cooling rate and / or to reduce residence times products in their cooling chamber. Of course, the invention is not limited to the embodiments described but encompasses any variant within the scope of the invention as defined by the claims. In particular: - although the drainage elements (conductive sole 31 and drainage element 37) have, here, a solid contact surface with the running slabs, these contact surfaces can advantageously be divided in order to reduce the surfaces in contact and thus the friction forces between these surfaces and the slabs 5 scrolling. These surfaces may comprise, for example, a plurality of disjoint cylindrical protrusions 38 as shown in FIGS. 8 to 10, metal brushes or a corrugated surface; - Although heat transfer fluids 22 and 33 are here pure water, the invention is also applicable to other types of heat transfer fluids such as sodium, oil or water comprising an additive such as propylene glycol; - Although here, the heat transfer link associating the radiative heat recovery means 20 with the thermally conductive conduits 21 for circulating the heat transfer fluid 22 is confused with said conduits, the invention also applies to recovery means radiant heat distinct from the fluid circulation ducts of the fins collecting the transmitter by conduction fins are fixed, by coolant such as radiation heat and the duct on which the welding for example; - Although here, the radiative heat 50 recovery circuit gives up its heat to a heating circuit 60, the invention also applies to a radiation heat recovery circuit supplying other equipment such as for example an expansion turbine, a heat exchanger with the circuit 100; -but here, the drainage elements are made of steel, the invention also applies to drainage elements made of another material such as, for example, copper or another metal, glass ... although here the solid products are moving metal slabs, the invention is also applicable to other solid products such as, for example, continuous rolled products, static solid products or non-solid products. metal such as glass, plastic, slag, biomass, ore or agri-food products. The invention relates to a drainage element in the form of a solid element, a set of solids divided as a powder or grains, a deformable product for example elastically, or a viscous liquid product.

The sole can be movable between a first support position of the slabs and a second position in which the slabs rest on the conveyor. In the case of a deformable solid or a viscous liquid, the supports can be fixed in height.

Claims (16)

REVENDICATIONS1. A device for sensing the heat emitted by a solid product in a cooling chamber, the device comprising means for heat recovery by conduction, these means comprising at least one drainage element, thermally conductive, arranged to be brought into contact with the less a surface of the solid product. 2. Device according to claim 1, wherein the heat recovery means by conduction comprises a heat transfer fluid circulating in a thermally conductive conduit in contact with the drainage element. 3. Device according to claim 2, wherein the coolant comprises a gas and / or a liquid. 4. Device according to claim 2, wherein the coolant feeds an expansion turbine. 5. Device according to claim 2, wherein the coolant feeds a heating circuit. 6. Device according to claim 1, wherein the drainage element comprises a sole on which the solid product rests. 7. Device according to claim 6, wherein the sole is provided with at least one thermally conductive conduit for circulating a heat transfer fluid. 8. Device according to claim 7, wherein at least one thermally conductive conduit for circulating a heat transfer fluid extends in a direction transverse to a running direction of the products in the cooling chamber. 9. Device according to claim 6, wherein the heat recovery means also comprise a thermally conductive drainage element in contact with an upper face of the solid product. 10. Device according to one of claims 6 to 9, wherein at least one of the drainage elements has a contact surface divided with the solid product. 11. Device according to any one of the preceding claims, the device also comprising radiative heat recovery means. 12. Device according to claim 11, wherein the radiative heat recovery means are associated, by a heat transfer link, to a heat transfer fluid flow conduit. 13. Device according to any one of the preceding claims, wherein the solid product is running in the cooling chamber. 14. Device according to any one of the preceding claims, wherein the solid product is a metal product. 15. Cooling enclosure for a scrollable solid product comprising at least one device according to any one of the preceding claims. 16. Enclosure according to claim 15, comprising successively, in the direction of travel of the solid product in the cooling chamber: radiative heat recovery means; - A conduction heat recovery device according to one of claims 6 to 9 and radiative heat recovery means; a conductive heat recovery device according to claim 10.