Flue gas desulfurization and denitrification and waste heat utilization system for hot-rolled wide strip steel heating furnace

Abstract

The invention belongs to the technical field of waste heat utilization, and particularly relates to a hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system which comprises a heating furnace, an air heat exchanger, a denitrification tower, a flue gas waste heat boiler, a desulfurization tower and a chimney which are communicated in sequence. And a primary waste heat utilization system and a secondary waste heat utilization system are respectively arranged in the flue gas waste heat boiler. Compared with the prior art, the flue gas desulfurization, denitrification and waste heat utilization system for the hot-rolled wide strip steel heating furnace has the advantages that the flue gas waste heat boiler is arranged between the denitrification tower and the desulfurization tower, so that waste heat of the flue gas at 350-400 DEG C at the outlet of the denitrification tower can be recycled by the flue gas waste heat boiler; besides, a two-stage waste heat utilization system is arranged in the flue gas waste heat boiler, waste heat of 350-400 DEG C to 250 DEG C and waste heat of 250-160 DEG C are recovered respectively, so that the recovery efficiency of the waste heat is higher, and meanwhile, the waste heat of 160 DEG C can just meet the requirement of the desulfurization tower for the temperature of the flue gas.

Description

Technical Field

[0001] The invention belongs to the technical field of waste heat utilization, and in particular relates to a flue gas desulfurization and denitrification and waste heat utilization system of a hot-rolled wide strip steel heating furnace. Background Art

[0002] Flue gas waste heat utilization refers to the process of recycling unused flue gas waste heat in energy utilization equipment. Flue gas waste heat utilization is an important way to improve economy and save fuel, and can significantly reduce energy consumption and environmental pollution.

[0003] In the energy expenditure of various industrial furnaces, waste heat from exhaust gas accounts for about 15% to 35%. After purification, these exhaust gases become a high-quality energy source that is easy to transport and use, does not require slag discharge and dust removal after combustion, and is not easy to cause environmental pollution.

[0004] At present, in the metallurgical field, the flue gas discharged from the hot-rolled wide steel heating furnace is often as high as 600℃~1100℃. The waste heat of these flue gases has not been well utilized, and the flue gases need to undergo denitrification and desulfurization processes respectively to meet the emission standards. The flue gas entering the desulfurization tower cannot be higher than 250℃. If it is higher than 250℃, the desulfurizer will become ineffective. Therefore, during desulfurization, the desulfurizer has temperature requirements, but the 250℃ flue gas directly entering the desulfurization tower will also make this part of the waste heat unable to be fully utilized.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace to solve the technical problems mentioned in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace comprises a heating furnace, an air heat exchanger, a denitrification tower, a flue gas waste heat boiler, a desulfurization tower and a chimney which are connected in sequence, wherein a primary waste heat utilization system and a secondary waste heat utilization system are respectively arranged in the flue gas waste heat boiler.

[0009] Preferably, an ammonia water nozzle is provided on the air inlet duct of the denitration tower.

[0010] Preferably, the ammonia water nozzles are arranged in double layers in the upper and lower air inlet ducts.

[0011] Preferably, the ammonia water nozzles on the upper layer and the ammonia water nozzles on the lower layer are arranged in a staggered manner.

[0012] Preferably, evenly distributed grids are provided on the air inlet duct of the denitration tower.

[0013] Preferably, the inlet flue gas temperature of the primary waste heat utilization system is 350-400°C, and the outlet flue gas temperature of the primary waste heat utilization system is 250°C.

[0014] Preferably, the inlet flue gas temperature of the secondary waste heat utilization system is 250°C, and the outlet flue gas temperature of the secondary waste heat utilization system is 160°C.

[0015] Preferably, the flue gas inlet temperature of the air heat exchanger is 600°C to 1100°C, and the flue gas outlet temperature of the air heat exchanger is 350°C to 400°C.

[0016] Compared with the prior art, the present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace, which has the following beneficial effects:

[0017] 1. The present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace. A flue gas waste heat boiler is arranged between a denitrification tower and a desulfurization tower. In this way, the flue gas waste heat boiler can be used to recycle the waste heat of 350-400°C flue gas at the outlet of the denitrification tower. In addition, a two-stage waste heat utilization system is arranged in the flue gas waste heat boiler to recycle waste heat from 350-400°C to 250°C and from 250°C to 160°C, respectively, so that the waste heat recovery efficiency is higher. At the same time, the waste heat of 160°C can just meet the temperature requirement of the desulfurization tower for the flue gas.

[0018] 2. The present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace. An ammonia water nozzle is arranged on the air inlet duct of the denitrification tower. By spraying ammonia water into the flue gas in advance, the denitrification efficiency of the denitrification tower can be improved. At the same time, the ammonia water nozzles are double-layered and staggered, so that the sprayed ammonia water is more uniform.

[0019] 3. The present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide-band steel heating furnace, in which evenly distributed grids are arranged on the air inlet duct of the denitrification tower. When the flue gas passes through the evenly distributed grids, it will be mechanically acted upon by the evenly distributed grids, making it evenly distributed, thereby further improving the denitrification efficiency of the denitrification tower.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a schematic structural diagram of a denitrification tower and a flue gas waste heat boiler in a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace proposed in an embodiment of the present invention.

[0023] Figure 2 A schematic structural diagram of a desulfurization tower and chimney in a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace proposed in an embodiment of the invention.

[0024] The diagram is as follows:

[0025] 1. Air inlet duct; 2. Ammonia spraying device; 3. Upper nozzle; 4. Lower nozzle; 5. Grille; 6. Denitrification tower; 7. Flue gas waste heat boiler; 8. Primary waste heat utilization system; 9. Secondary waste heat utilization system; 10. Desulfurization tower; 11. Draft fan; 12. Motor; 13. Chimney; 14. Flue gas outlet; 15. Flue gas inlet. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0027] like Figure 1-2 As shown, an embodiment of the present invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace, comprising a heating furnace, an air heat exchanger, a denitrification tower 6, a flue gas waste heat boiler 7, a desulfurization tower 10 and a chimney 13 connected in sequence. It should be noted that the heating furnace and the air heat exchanger are conventional devices in the field of technology, so the structure of the heating furnace and the air heat exchanger are not shown in the figure.

[0028] The embodiment of the invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace, in which a primary waste heat utilization system 8 and a secondary waste heat utilization system 9 are respectively arranged in the flue gas waste heat boiler 7. In this way, the flue gas waste heat boiler 7 is arranged between the denitrification tower 6 and the desulfurization tower 10, and the flue gas waste heat boiler 7 can be used to recycle the waste heat of the 350-400°C flue gas at the outlet of the denitrification tower 6; in addition, a two-stage waste heat utilization system is arranged in the flue gas waste heat boiler 7, which recycles the waste heat from 350-400°C to 250°C and from 250°C to 160°C, respectively, so that the waste heat recovery efficiency is higher, and at the same time, the waste heat of 160°C can just meet the temperature requirement of the desulfurization tower 10 for the flue gas.

[0029] The embodiment of the invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace, wherein an ammonia spraying device 2 is provided on the air inlet duct 1 of the denitrification tower 6, and the ammonia spraying device 2 is provided with ammonia water nozzles arranged in a double layer up and down, and the upper layer nozzles and the lower layer nozzles are arranged in a staggered manner. In this embodiment, an ammonia water nozzle is provided on the air inlet duct 1 of the denitrification tower 6, and the denitrification efficiency of the denitrification tower 6 can be improved by spraying ammonia water into the flue gas in advance, and at the same time, the ammonia water nozzles are arranged in a double layer up and down and staggered, so that the sprayed ammonia water is more uniform.

[0030] An embodiment of the invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace. The air inlet duct 1 of the denitrification tower 6 is provided with evenly distributed grilles 5. In this embodiment, the air inlet duct 1 of the denitrification tower 6 is provided with evenly distributed grilles 5. When the flue gas passes through the evenly distributed grilles 5, it will be subjected to the mechanical action of the evenly distributed grilles 5, so that it is evenly distributed, thereby further improving the denitrification efficiency of the denitrification tower 6.

[0031] The embodiment of the invention provides a flue gas desulfurization, denitrification and waste heat utilization system for a hot-rolled wide strip steel heating furnace, wherein the flue gas inlet temperature of the air heat exchanger is 600°C to 1100°C, and the flue gas outlet temperature of the air heat exchanger is 350 to 400°C; the inlet flue gas temperature of the primary waste heat utilization system 8 is 350 to 400°C, and the outlet flue gas temperature of the primary waste heat utilization system 8 is 250°C; the inlet flue gas temperature of the secondary waste heat utilization system 9 is 250°C, and the outlet flue gas temperature of the secondary waste heat utilization system 9 is 160°C. The flue gas outlet of the secondary waste heat utilization system 9 is connected to the flue gas inlet 15 of the desulfurization tower 10, and the flue gas at 160°C enters the desulfurization tower 10 for desulfurization, and the flue gas after desulfurization is discharged through the chimney 13 by the induced draft fan 11 and the motor 12 to meet the requirements.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0033] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

Claims

1. A system for desulfurization, denitrification and waste heat utilization of flue gas in a hot-rolled wide steel heating furnace, characterized in that: It comprises a heating furnace, an air heat exchanger, a denitrification tower, a flue gas waste heat boiler, a desulfurization tower and a chimney which are connected in sequence, and a primary waste heat utilization system and a secondary waste heat utilization system are respectively arranged in the flue gas waste heat boiler.

2. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 1, characterized in that: An ammonia water nozzle is arranged on the air inlet pipe of the denitration tower.

3. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 2, characterized in that: The ammonia water nozzles are arranged in double layers above and below the air inlet duct.

4. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 3, characterized in that: The ammonia water nozzles on the upper layer and the ammonia water nozzles on the lower layer are arranged in a staggered manner.

5. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 4, characterized in that: Evenly distributed grids are arranged on the air inlet duct of the denitration tower.

6. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 5, characterized in that: The inlet flue gas temperature of the first-stage waste heat utilization system is 350-400°C, and the outlet flue gas temperature of the first-stage waste heat utilization system is 250°C.

7. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 6, characterized in that: The inlet flue gas temperature of the secondary waste heat utilization system is 250°C, and the outlet flue gas temperature of the secondary waste heat utilization system is 160°C.

8. A hot-rolled wide strip steel heating furnace flue gas desulfurization, denitrification and waste heat utilization system according to claim 7, characterized in that: The flue gas inlet temperature of the air heat exchanger is 600°C to 1100°C, and the flue gas outlet temperature of the air heat exchanger is 350°C to 400°C.

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