Waste heat gradient utilization heat exchange system

Abstract

The utility model discloses a heat exchange system for gradient utilization of waste heat. The heat exchange system comprises a fluidized bed cooling system, a flue gas waste heat recovery system, a three-stage waste heat exchange system, flat plate washing water and demineralized water, the flat plate washing water sequentially enters the fluidized bed cooling system and the flue gas waste heat recovery system for heat exchange and temperature rise, the flat plate washing water heated by the flue gas waste heat exchange system exchanges heat with demineralized water through the three-stage waste heat exchange system, and the flat plate washing water discharged from the three-stage waste heat exchange system is conveyed into the flat plate hot water tank; and the demineralized water heated by the three-stage waste heat exchange system enters the flue gas waste heat recovery system for heat exchange and heating, and the demineralized water heated by the flue gas waste heat recovery system is conveyed to a thermal power station. The heat gradient utilization design can be carried out according to the requirements of all working procedures, it is ensured that high-grade heat is preferentially utilized, temperature fluctuation of a heat exchange medium is stabilized, the overall energy utilization efficiency is improved, and heat loss is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a roasting furnace waste heat recovery technical field especially relates to a waste heat heat cascade utilization heat exchange system. BACKGROUND

[0002] The roasting furnace flue gas waste heat utilization technology has important application value in the current industrial field. By effectively utilizing the waste heat in the flue gas discharged by the roasting furnace, not only the energy utilization efficiency can be improved, the production cost can be reduced, but also the environmental pollution can be reduced, and the sustainable development can be realized. The roasting furnace flue gas waste heat utilization mainly depends on heat exchangers, heat pipes and other equipment, and the heat in the flue gas is recovered and used in other processes through heat conduction, convection and other modes. However, the current means for heat recovery is to directly put the medium into the flue gas heat exchanger for heat exchange, and after the heat exchange is finished, the medium is directly used in the subsequent process. Due to the characteristics of complex composition of the flue gas of the roasting furnace, large temperature fluctuation and the like, vaporization, condensation and other phenomena are easily generated in the instant cold-hot alternation, which causes the adhesion of the inner wall of the heat exchange tube bundle, affects the heat exchange efficiency, increases the utilization difficulty of the waste heat recovery, and thus causes the temperature fluctuation of the medium after heat exchange to change, and the temperature fluctuation may affect the utilization of the subsequent process. Secondly, the existing technology has low recovery efficiency in the aspect of roasting furnace flue gas waste heat utilization, and the flue gas after the flue gas processor is directly discharged through the chimney, so that a large amount of heat energy cannot be effectively utilized. Therefore, the present application provides a waste heat heat cascade utilization heat exchange system to improve the roasting furnace and fluidized bed waste heat utilization efficiency. SUMMARY

[0003] The utility model provides a waste heat heat cascade utilization heat exchange system, and the heat cascade utilization design is carried out in combination with the demand between each process, high-grade heat is ensured to be utilized preferentially, the temperature fluctuation of heat exchange medium is stabilized, the overall energy utilization efficiency is improved, and the loss of heat is reduced.

[0004] In order to realize the above-mentioned purpose, the technical scheme that the utility model adopts is as follows:

[0005] A waste heat heat cascade utilization heat exchange system, comprising a fluidized bed cooling system, a flue gas waste heat recovery system, a three-stage waste heat heat exchange system, a flat disc washing water and desalted water, the flat disc washing water is sequentially heat exchanged and heated in the fluidized bed cooling system and the flue gas waste heat recovery system, the flat disc washing water after being heated by the flue gas waste heat heat exchange system is exchanged heat with the desalted water by the three-stage waste heat heat exchange system, and the flat disc washing water after the three-stage waste heat heat exchange system is transported to a flat disc hot water tank.

[0006] Further, the flue gas heat exchange system comprises at least two flue gas heat exchangers; the two flue gas heat exchangers are respectively arranged as a first flue gas heat exchanger and a second flue gas heat exchanger; the flat disc washing water from the fluidized bed cooling system is transported to the first flue gas heat exchanger to exchange heat with flue gas waste heat and is heated, and the flat disc washing water from the first flue gas heat exchanger is transported to the three-stage waste heat exchange system, and the desalted water from the three-stage waste heat exchange system is transported to the second flue gas heat exchanger.

[0007] Further, the heat source inlet of each flue gas heat exchanger is connected with a flue gas processor through a draught fan, and the heat source outlet of each flue gas heat exchanger is connected with a chimney.

[0008] Further, the fluidized bed cooling system comprises a plurality of fluidized bed heat exchangers, the flat disc washing water is transported to each fluidized bed heat exchanger to exchange heat and is heated, and all the flat disc washing water from each fluidized bed heat exchanger is collected in the same pipeline and is transported to the first flue gas heat exchanger.

[0009] Further, the three-stage waste heat exchange system comprises a plate heat exchanger; the flat disc washing water from the first flue gas heat exchanger is transported to the heat source inlet end of the plate heat exchanger, the flat disc washing water from the heat source outlet end of the plate heat exchanger is transported to the flat disc hot water tank, the desalted water is transported to the cold source inlet end of the plate heat exchanger through a desalted water pressurizing pump from a desalted water station, the desalted water from the cold source outlet end of the plate heat exchanger is transported to the cold source inlet end of the second flue gas heat exchanger, and the desalted water from the cold source outlet end of the second flue gas heat exchanger is transported to the thermal power station.

[0010] The utility model discloses the beneficial effects are:

[0011] 1) the utility model discloses a fluidized bed cooling system, flue gas waste heat recovery system, three-stage waste heat exchange system carry out heat cascade utilization, can make flat disc washing water first heating control temperature, combine the demand between each process, utilize three-stage waste heat exchange system to stabilize flat disc washing water temperature and preheat desalted water, and the desalted water after heating is heated again through flue gas waste heat recovery system heat exchange, and this heat exchange process can ensure that high-grade heat is preferentially utilized, and simultaneously also reduce the phenomenon of vaporization, condensation and the like caused by large temperature difference when heat exchange in the flue gas waste heat recovery system, improve overall energy utilization efficiency, and reduce heat loss.

[0012] 2) the first flue gas heat exchanger and the second flue gas heat exchanger in the utility model are arranged at the end of the corresponding roasting furnace flue gas discharge, and then the waste heat of the end flue gas is recycled and utilized, overall energy utilization efficiency is improved, and heat loss is reduced.

[0013] 3) flat disc washing water is preheated by fluidized bed cooling system, gets balanced temperature, then enters into the first flue gas heat exchanger to exchange heat, which can avoid vaporization phenomenon caused by large instantaneous temperature difference, the flat disc washing water from the first flue gas heat exchanger exchanges heat with desalted water through the plate heat exchanger, so that the flat disc washing water is reduced to the temperature condition suitable for the use of the subsequent process, and the temperature is more stable; and the desalted water can also be preheated by the plate heat exchanger before entering into the second flue gas heat exchanger to exchange heat and increase temperature, so as to avoid vaporization phenomenon. BRIEF DESCRIPTION OF DRAWINGS

[0014] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings, in which:

[0015] Figure 1 It is a structural schematic diagram of the present application;

[0016] The figure mark is:

[0017] 1-fluidized bed cooling system, 2-flue gas waste heat recovery system, 3-three-stage waste heat exchange system, 4-flat disc washing water, 5-desalted water, 6-flat disc hot water tank, 7-thermal power station, 8-desalted water station, 9-desalted water pressurizing pump, 11-fluidized bed heat exchanger, 21-first flue gas heat exchanger, 22-and second flue gas heat exchanger. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] It should be noted that when a component is referred to as being "fixed" to another component, it can be directly on the other component or there can be intervening components. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or there can be intervening components. When a component is referred to as being "disposed on" another component, it can be directly disposed on the other component or there can be intervening components. When a component is referred to as being "disposed in the middle", it is not only disposed in the middle position, but also falls within the range defined by the middle. The terms "vertical", "horizontal", "left", "right", and similar expressions used herein are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0021] Referring to Figure 1 As shown in the figure, a waste heat heat cascade utilization heat exchange system, comprising a fluidized bed cooling system 1, a flue gas waste heat recovery system 2, a three-stage waste heat heat exchange system 3, a flat disc washing water 4 and desalted water 5; the flat disc washing water 4 enters the fluidized bed cooling system 1, the flue gas waste heat recovery system 2 in turn, and the flat disc washing water 4 after being heated by the flue gas waste heat recovery system 2 is exchanged with the desalted water 5 by the three-stage waste heat heat exchange system 3, and the flat disc washing water 4 after being heated by the three-stage waste heat heat exchange system 3 is transported to the flat disc hot water tank 6; the desalted water 5 after being heated by the three-stage waste heat heat exchange system 3 is transported to the flue gas waste heat recovery system 2, and the desalted water 5 after being heated by the flue gas waste heat recovery system 2 is transported to the thermal power station 7. The heat cascade utilization of the fluidized bed cooling system 1, the flue gas waste heat recovery system 2 and the three-stage waste heat heat exchange system 3 can make the flat disc washing water 4 first heated and then controlled, and the temperature of the flat disc washing water 4 is stabilized by the three-stage waste heat heat exchange system 3 while the desalted water 5 is preheated, and the desalted water 5 after being heated is heated again by the flue gas waste heat recovery system 2, which can ensure that the high-grade heat is utilized preferentially, and can also avoid the phenomenon of vaporization and condensation caused by large temperature difference during heat exchange in the flue gas waste heat recovery system 2, improve the overall energy utilization efficiency, and reduce the loss of heat.

[0022] The flue gas heat exchange system 2 comprises at least two flue gas heat exchangers; the two flue gas heat exchangers are respectively provided as a first flue gas heat exchanger 21 and a second flue gas heat exchanger 22; the flat disc washing water 4 from the fluidized bed cooling system 1 is transported to the first flue gas heat exchanger 21 to exchange heat with flue gas waste heat and is heated, the flat disc washing water 4 from the first flue gas heat exchanger 21 is transported to the three-stage waste heat exchange system 3, and the desalted water 5 from the three-stage waste heat exchange system 3 is transported to the second flue gas heat exchanger 22. The heat source inlet of each flue gas heat exchanger is connected with a flue gas processor through a draught fan, and the heat source outlet of each flue gas heat exchanger is connected with a chimney. In the embodiment, the first flue gas heat exchanger 21 and the second flue gas heat exchanger 22 are respectively connected to different draught fans, flue gas processors and chimneys. In the conventional technology, the flue gas at the end of the roasting furnace flue gas discharge end is directly discharged through a chimney, while the first flue gas heat exchanger 21 and the second flue gas heat exchanger 22 can utilize the waste heat of the flue gas at the end of the roasting furnace flue gas discharge end again, improve the energy utilization efficiency and reduce the heat loss.

[0023] The fluidized bed cooling system 1 comprises a plurality of fluidized bed heat exchangers 11, the flat disc washing water 4 is transported to each fluidized bed heat exchanger 11 to exchange heat and is heated, all the flat disc washing water 4 from each fluidized bed heat exchanger 11 is collected to the same pipeline and is transported to the first flue gas heat exchanger 21. The three-stage waste heat exchange system 3 comprises a plate heat exchanger; the flat disc washing water 4 from the first flue gas heat exchanger 21 is transported to the heat source inlet end of the plate heat exchanger, the flat disc washing water 4 from the heat source outlet end of the plate heat exchanger is transported to the flat disc hot water tank 6; the desalted water 5 is transported to the cold source inlet end of the plate heat exchanger from the desalted water station 8 through a desalted water pressurizing pump 9, the desalted water 5 from the cold source outlet end of the plate heat exchanger is transported to the cold source inlet end of the second flue gas heat exchanger 22; the desalted water 5 from the cold source outlet end of the second flue gas heat exchanger 22 is transported to the thermal power station 7. The flat disc washing water 5 is preheated through the fluidized bed cooling system 1 to obtain balanced temperature, and then enters the first flue gas heat exchanger 21 to exchange heat, so that the vaporization phenomenon caused by large instantaneous temperature difference can be avoided, the flat disc washing water 4 from the first flue gas heat exchanger 21 is further exchanged with the desalted water 5 through the plate heat exchanger, so that the flat disc washing water 4 is reduced to a temperature condition suitable for use in subsequent processes, and the temperature is more stable; and the desalted water 5 can also be preheated through the plate heat exchanger before being exchanged with the second flue gas heat exchanger 22, so that the vaporization phenomenon can be avoided.

[0024] The above embodiment is only used to illustrate the technical scheme of the present application and does not limit the same, and any modification or equivalent replacement without departing from the spirit and scope of the present application shall be covered in the scope of the technical scheme of the present application.

Claims

1. A waste heat cascade utilization heat exchange system, characterized in that, The system includes a fluidized bed cooling system, a flue gas waste heat recovery system, a three-stage waste heat exchange system, a flatbed wash water system, and demineralized water. The flatbed wash water sequentially enters the fluidized bed cooling system and the flue gas waste heat recovery system for heat exchange and temperature increase. After being heated by the flue gas waste heat exchange system, the flatbed wash water exiting the system exchanges heat with the demineralized water through the three-stage waste heat exchange system. The flatbed wash water exiting the three-stage waste heat exchange system is then transported to a flatbed hot water tank. The demineralized water exiting the system after being heated by the three-stage waste heat exchange system enters the flue gas waste heat recovery system for heat exchange and temperature increase. After the demineralized water is heated by the flue gas waste heat recovery system, it is then transported to the thermal power plant.

2. The waste heat cascade utilization heat exchange system according to claim 1, characterized in that, The flue gas heat exchange system includes at least two flue gas heat exchangers; the two flue gas heat exchangers are respectively designated as flue gas heat exchanger No. 1 and flue gas heat exchanger No. 2; the flat plate wash water from the fluidized bed cooling system is transported to the first flue gas heat exchanger to exchange heat with the waste heat of the flue gas and increase its temperature; the flat plate wash water from the first flue gas heat exchanger is transported to the third-stage waste heat exchange system; and the demineralized water from the third-stage waste heat exchange system is transported to the second flue gas heat exchanger.

3. The waste heat cascade utilization heat exchange system according to claim 2, characterized in that, The heat source inlet of each of the flue gas heat exchangers is connected to a flue gas processor via an induced draft fan, and the heat source outlet of each of the flue gas heat exchangers is connected to a chimney.

4. The waste heat cascade utilization heat exchange system according to claim 2, characterized in that, The fluidized bed cooling system includes several fluidized bed heat exchangers. The flat plate wash water is delivered to each of the fluidized bed heat exchangers for heat exchange and temperature increase. All the flat plate wash water coming out of each of the fluidized bed heat exchangers is collected into the same pipeline and delivered to the No. 1 flue gas heat exchanger.

5. A waste heat cascade utilization heat exchange system according to claim 3, characterized in that, The three-stage waste heat exchange system includes a plate heat exchanger; the plate wash water from the first flue gas heat exchanger is transported to the heat source inlet of the plate heat exchanger, and the plate wash water from the heat source outlet of the plate heat exchanger is transported to the plate hot water tank; the demineralized water is transported from the demineralized water station to the cold source inlet of the plate heat exchanger via a demineralized water pressurization pump, and the demineralized water from the cold source outlet of the plate heat exchanger is transported to the cold source inlet of the second flue gas heat exchanger; the demineralized water from the cold source outlet of the second flue gas heat exchanger is transported to the thermal power plant.

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