Efficient and environment-friendly sinter cooler waste heat recovery power generation system

Abstract

The utility model discloses an efficient and environment-friendly sinter cooler waste heat recovery power generation system, and belongs to the technical field of waste heat recovery and utilization in the iron and steel smelting industry. The problems that in the prior art, due to the fact that a plurality of fans are connected in parallel to conduct subsection cooling on a sinter cooler, sinter is broken due to quenching, the yield is low, the quality index of finished ore is relatively low, and low-temperature waste gas in the middle section and the rear section is emptied or utilized in a low-efficiency mode are solved. According to the technical key points, when the sinter cooler is divided into five sections, waste gas exhausted from the third section of the annular cooler is collected and is conveyed to the inlet end of a fan of the first section of the annular cooler through a pipeline, and a two-stage heating system for the waste gas is formed; waste gas exhausted from the fourth section of the circular cooler is collected and conveyed to the inlet end of a fan of the second section of the circular cooler through a pipeline, and a second-stage heating system for the waste gas is also formed. Low-temperature waste gas and mineral aggregate are subjected to two-stage heat exchange, the temperature is gradually increased, the purpose that the temperature of the waste gas is obviously increased compared with the prior art is achieved, and therefore heat in the waste gas is efficiently recycled for power generation.

Description

Technical Field

[0001] The utility model relates to a sinter cooler waste heat recovery power generation system, in particular to a high-efficiency and environmentally friendly sinter cooler waste heat recovery power generation system, belonging to the technical field of waste heat recovery and utilization in the steel smelting industry. Background Art

[0002] According to the currently known information, the existing sintering cooler and waste heat utilization system, see Figure 3 Generally, the high-temperature exhaust gas from the first two stages is recovered, and after the waste heat boiler absorbs the heat, the exhaust gas is sent to the lower part of the first two stages of the cooler for blasting using hot air circulation. In this exhaust gas circulation system, the exhaust gas temperature discharged from the waste heat boiler is relatively low.

[0003] In recent years, there is also a technology to recover the waste heat of the 3rd and 4th stage low-temperature exhaust gas. For the 3rd and 4th stage low-temperature exhaust gas waste heat recovery system, see Figure 4 The principle is simply to recover the waste heat from the exhaust gas in sections 1 and 2 and simply expand it to sections 3 and 4. The principle is also parallel exhaust gas circulation.

[0004] In the prior art, the sintering cooler uses parallel fans for segmented cooling, and waste heat recovery can generally only use the first 1 / 3 of the waste gas for circulation. The current model has the following defects:

[0005] 1. The waste gas from the 3rd to 5th sections at the rear of the sintering cooler is generally not recycled, and a large amount of waste gas is directly discharged, causing a certain degree of pollution to the environment.

[0006] 2. The sintering cooler uses multiple fans in parallel for segmented cooling, which results in direct contact between cold air and high-temperature sintered ore, resulting in a low yield rate due to rapid cooling and crushing of the sintered ore, and relatively low quality indicators of the finished ore.

[0007] 3. The sintering cooler uses multiple fans in parallel for staged cooling, which results in low exhaust gas temperature in the middle and rear sections of the cooler. It can only use the waste heat of the high-temperature exhaust gas in the front section. The waste heat power generation is generally below 20kWh per ton of ore. In addition, a large amount of low-temperature exhaust gas with a temperature of 130 to 250°C in the middle and rear sections is discharged or inefficiently utilized, resulting in a large amount of heat loss, which does not meet the increasingly high requirements for extreme energy efficiency.

[0008] 4. The sintering cooler uses multiple fans in parallel for staged cooling, which results in a significant reduction in the exhaust gas temperature in stages 1 and 2 when the sintering ore output is low, thereby significantly reducing the existing waste heat power generation efficiency and even causing the waste heat power generation unit to shut down. Utility Model Content

[0009] In view of the above facts, the purpose of the utility model is to solve the problems of low yield rate and relatively low quality index of finished ore due to rapid cooling and crushing of sintered ore in the existing technology, the problem of low-temperature waste gas discharge or inefficient utilization in the middle and rear stages; and the problem that when the sintered ore output is low, the waste gas temperature of the 1st and 2nd stages is greatly reduced, which greatly reduces the waste heat power generation efficiency and even the waste heat power generation unit is shut down, and then design a high-efficiency and environmentally friendly sintered ore cooler waste heat recovery power generation system. The utility model is used in the occasion of sintered ore cooling in steel production, which can greatly improve the waste heat recovery power generation efficiency, reduce waste gas emissions, and improve the yield rate of cooled materials. The utility model is used in the sintered ore cooling process of steel production, which can greatly reduce the waste gas discharged by the cooler, can greatly improve the level of sintering waste heat power generation, and improve the quality of sintered ore. The waste heat power generation of the sintering cooler can reach more than 28kWh per ton of ore, and can also reduce the self-use electricity rate of the sintering waste heat recovery system.

[0010] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0011] Solution: An efficient and environmentally friendly sinter cooler waste heat recovery power generation system, including a waste heat boiler power generation system and an ORC power generation system. The flue gas from the first section and the second section of the ring cooler are respectively transmitted to the top of the waste heat boiler of the waste heat boiler power generation system through the high-temperature flue. The flue gas outlet of the waste heat boiler is connected to the shell side of the organic working fluid heat exchanger through the exhaust flue, and the tube side of the organic working fluid heat exchanger is cyclically connected to the ORC power generation system.

[0012] When the sinter cooler has 5 stages, the bottom of the shell side of the organic working medium heat exchanger is connected to the inlet end of the fan of the 3rd stage and the 4th stage of the ring cooler through a pipeline, the exhaust gas outlet of the 4th stage of the ring cooler is connected to the inlet end of the fan of the 2nd stage of the ring cooler through a pipeline, and the exhaust gas outlet of the 3rd stage of the ring cooler is connected to the inlet end of the fan of the 1st stage of the ring cooler through a pipeline;

[0013] When the sintered ore cooler has 7 sections, the bottom of the shell side of the organic working fluid heat exchanger is connected to the inlet end of the fan of the 5th section and the 6th section of the ring cooler through a pipeline, the exhaust gas outlet of the 6th section of the ring cooler is connected to the inlet end of the fan of the 4th section of the ring cooler through a pipeline, and the exhaust gas outlet of the 5th section of the ring cooler is connected to the inlet end of the fan of the 3rd section of the ring cooler through a pipeline; the exhaust gas outlet of the 4th section of the ring cooler is connected to the inlet end of the fan of the 2nd section of the ring cooler through a pipeline, and the exhaust gas outlet of the 3rd section of the ring cooler is connected to the inlet end of the fan of the 1st section of the ring cooler through a pipeline.

[0014] Further: when the sintered ore cooler has 5 stages, the flue gas temperature of the first stage of the ring cooler is 470-510°C, the flue gas temperature of the second stage of the ring cooler is 300-350°C, the exhaust gas temperature of the third stage of the ring cooler is 200-230°C, the exhaust gas temperature of the fourth stage of the ring cooler is 130-163°C, the exhaust gas temperature of the fifth stage of the ring cooler is 70-90°C, and the lower circulating exhaust gas temperature of the low-temperature combined waste heat boiler is 150°C.

[0015] Furthermore: the working pressure of the waste heat boiler is 3.0-3.5 MPa.

[0016] Furthermore: the organic working fluid of the ORC power generation system is R245fa.

[0017] Furthermore: a waste heat boiler induced draft fan is installed on the pipeline at the bottom of the shell side of the organic working fluid heat exchanger.

[0018] The effects achieved by the utility model are:

[0019] The utility model utilizes the existing sintering ring cooling or belt cooling machine body to transform the cooling blower and the waste gas collection system. When the sintering ore cooler is 5-stage, the waste gas discharged from the 3rd stage of the ring cooling machine is collected and sent to the inlet end of the fan of the 1st stage of the ring cooling machine through a pipeline, forming a two-stage heating system for the waste gas; the waste gas discharged from the 4th stage of the ring cooling machine is collected and sent to the inlet end of the fan of the 2nd stage of the ring cooling machine through a pipeline, also forming a two-stage heating system for the waste gas; when the sintering ore cooler is 7-stage, the waste gas discharged from the 6th stage of the ring cooling machine is also collected and sent to the inlet end of the fan of the 4th stage of the ring cooling machine through a pipeline, forming a two-stage heating system for the waste gas; the waste gas discharged from the 5th stage of the ring cooling machine is collected and sent to the inlet end of the fan of the 4th stage of the ring cooling machine through a pipeline, forming a two-stage heating system for the waste gas The exhaust gas is sent to the inlet of the fan of the third section of the ring cooler, forming a two-stage heating system for the exhaust gas. The low-temperature exhaust gas is used to undergo heat exchange with the ore in the second stage, and the temperature is gradually increased, achieving a significant increase in the exhaust gas temperature compared to the prior art, and then the waste heat is recovered. The high-temperature exhaust gas is equipped with a high-parameter waste heat boiler (working pressure 3.5MPa, the working pressure of the prior art is 2.0MPa) to produce high-quality waste heat steam, forming a complete set of high-efficiency waste heat power generation system. The exhaust gas discharged from the waste heat boiler is then cooled to about 80°C through an organic working fluid heat exchanger for ORC power generation, and is sent to the inlet of the fan in the medium and low temperature sections. In this way, the exhaust gas is recycled to achieve the purpose of reducing exhaust gas emissions.

[0020] The utility model not only reduces the exhaust gas emission of the sinter cooler, optimizes the cooling effect of the ore material, and improves the finished product rate, but also greatly increases the waste heat power generation, and can make full use of the original sinter cooler and auxiliary equipment, greatly saving investment and effectively shortening the investment payback period of the project.

[0021] 1. The two-stage heating mode of sinter cooler exhaust gas is adopted, which not only reduces the exhaust gas emission of the cooler and significantly improves the environmental pollution near the cooler, but also greatly improves the exhaust gas waste heat recovery efficiency and waste heat power generation efficiency, making a positive contribution to energy conservation and environmental protection of the steel plant.

[0022] 2. The two-stage series heating of the sinter cooler exhaust gas can obtain higher temperature exhaust gas, recover more heat from the exhaust gas, and improve the quality of the exhaust gas. The waste heat boiler can produce waste heat steam with higher parameters, greatly improving the power generation efficiency of the waste heat generator set. In addition, the ORC unit at the tail of the waste heat boiler further recovers heat for power generation. The technology of the utility model can achieve waste heat power generation of more than 30kWh per ton of sinter cooler.

[0023] 3. The circulating fan of the original technology has high power consumption and is the most important power-consuming equipment in the waste heat power generation system. The utility model cancels the circulating fan of the original waste heat boiler and replaces it with an induced draft fan, which can greatly reduce the self-consumption rate.

[0024] 4. The utility model can make full use of the original sintered ore cooler and auxiliary machines, only transform the fan and exhaust gas system, and set a high-parameter waste heat boiler, which can reduce project investment.

[0025] 5. Adding a low-temperature organic working fluid heat exchanger and an ORC generator set at the discharge of the existing waste heat boiler can reduce the circulating exhaust gas temperature to about 80°C, and then send it back to the fan inlet of the medium and low temperature sections, which can ensure the cooling effect of the cooler and ensure that the cooler discharge temperature is qualified. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a high-efficiency and environmentally friendly sinter cooler waste heat recovery power generation system of the utility model;

[0027] Figure 2 This is a schematic diagram of the structure of the waste heat recovery power generation system when the sinter cooler is 7 stages;

[0028] Figure 3 It is a structural schematic diagram of the existing sintering cooler and waste heat utilization system;

[0029] Figure 4 It is a schematic diagram of the structure of the 3rd and 4th stage low-temperature exhaust gas waste heat recovery system.

[0030] Among them: 1-waste heat boiler power generation system; 2-ORC power generation system; 3-organic working fluid heat exchanger; 4-high temperature flue; 5-exhaust flue; 6-fan; 7-waste heat boiler induced draft fan. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so as to describe the embodiments of the present application described herein.

[0033] In the present application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "back", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0034] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Figure 1 The present application is described in detail with reference to embodiments.

[0036] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] Example 1: Combination Figure 1 The present embodiment describes an efficient and environmentally friendly sinter cooler waste heat recovery power generation system, including a waste heat boiler power generation system 1 and an ORC power generation system 2. The flue gas of the first section and the second section of the ring cooler are respectively transmitted to the top of the waste heat boiler of the waste heat boiler power generation system through the high-temperature flue 4. The flue gas outlet of the waste heat boiler is connected to the shell side of the organic working fluid heat exchanger 3 through the exhaust flue 5. The tube side of the organic working fluid heat exchanger 3 is cyclically connected to the ORC power generation system 2.

[0038] When the sinter cooler has 5 stages, the bottom of the shell side of the organic working medium heat exchanger 3 is connected to the inlet end of the fan 6 of the ring cooler 3 and the ring cooler 4 through a pipeline, the exhaust gas outlet of the ring cooler 4 is connected to the inlet end of the fan 6 of the ring cooler 2 through a pipeline, and the exhaust gas outlet of the ring cooler 3 is connected to the inlet end of the fan 6 of the ring cooler 1 through a pipeline;

[0039] When the sintered ore cooler has 5 stages, the flue gas temperature of the first stage of the ring cooler is 493°C, the flue gas temperature of the second stage of the ring cooler is 330°C, the waste gas temperature of the third stage of the ring cooler is 222°C, the waste gas temperature of the fourth stage of the ring cooler is 163°C, the waste gas temperature of the fifth stage of the ring cooler is 75°C, and the lower circulating waste gas temperature of the low-temperature combined waste heat boiler is 150°C. The working pressure of the waste heat boiler is 3.5MPa. The organic working fluid of the ORC power generation system 2 is R245fa. A waste heat boiler induced draft fan 7 is installed on the pipeline at the bottom of the shell side of the organic working fluid heat exchanger 3.

[0040] Example 2: Combination Figure 2 The difference between the present embodiment and the embodiment 1 is that the present embodiment is a high-efficiency and environmentally friendly sinter cooler waste heat recovery power generation system, the sinter cooler is composed of 7 sections, the bottom of the shell side of the organic working fluid heat exchanger 3 is connected to the inlet end of the fan 6 of the ring cooler section 5 and the ring cooler section 6 through a pipeline, the exhaust gas outlet of the ring cooler section 6 is connected to the inlet end of the fan 6 of the ring cooler section 4 through a pipeline, the exhaust gas outlet of the ring cooler section 5 is connected to the inlet end of the fan 6 of the ring cooler section 3 through a pipeline; the exhaust gas outlet of the ring cooler section 4 is connected to the inlet end of the fan 6 of the ring cooler section 2 through a pipeline, and the exhaust gas outlet of the ring cooler section 3 is connected to the inlet end of the fan 6 of the ring cooler section 1 through a pipeline.

[0041] With 1 unit of 360m 2 Taking the sintering ring cooler as an example, the following heat balance simulation calculations of the sintering ring cooler and the heat balance simulation calculations of the sintering waste heat utilization are provided as follows:

[0042]

[0043]

[0044] The above simulation calculations show that:

[0045] 1. The discharge temperature of the ring cooler is 80℃, which is lower than the 120℃ required by the specification.

[0046] 2. The waste gas circulation is realized, achieving the environmental protection effect of reducing waste gas emissions.

[0047] 3. The recovery of more heat from the cooler is achieved for power generation. Combined with the power generation capacity of the ORC unit, the waste heat power generation capacity can still reach 13.8MW, and the power generation capacity per ton of ore reaches 31.8kWh, which is a significant improvement over the existing waste heat power generation capacity of 20kWh per ton of ore.

[0048] 4. The existing sintering ring cooler and auxiliary equipment can be fully utilized, and the total investment can be saved by more than 50% compared with the new cooling kiln solution.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

[0050] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An efficient and environmentally friendly sinter cooler waste heat recovery power generation system, comprising a waste heat boiler power generation system (1) and an ORC power generation system (2), wherein the flue gas of the first section and the second section of the ring cooler are respectively transmitted to the top of the waste heat boiler of the waste heat boiler power generation system through a high-temperature flue (4), the flue gas outlet of the waste heat boiler is connected to the shell side of the organic working fluid heat exchanger (3) through a flue gas exhaust duct (5), and the tube side of the organic working fluid heat exchanger (3) is cyclically connected to the ORC power generation system (2); the characteristics are: When the sintered ore cooler has five stages, the bottom of the shell side of the organic working medium heat exchanger (3) is connected to the inlet ends of the fans (6) of the third and fourth stages of the ring cooler through a pipeline, the exhaust gas outlet of the fourth stage of the ring cooler is connected to the inlet end of the fan (6) of the second stage of the ring cooler through a pipeline, and the exhaust gas outlet of the third stage of the ring cooler is connected to the inlet end of the fan (6) of the first stage of the ring cooler through a pipeline; When the sintered ore cooler has 7 sections, the bottom of the shell side of the organic working fluid heat exchanger (3) is connected to the inlet ends of the fans (6) of the 5th and 6th sections of the ring cooler through a pipeline, the exhaust gas outlet of the 6th section of the ring cooler is connected to the inlet end of the fan (6) of the 4th section of the ring cooler through a pipeline, and the exhaust gas outlet of the 5th section of the ring cooler is connected to the inlet end of the fan (6) of the 3rd section of the ring cooler through a pipeline; the exhaust gas outlet of the 4th section of the ring cooler is connected to the inlet end of the fan (6) of the 2nd section of the ring cooler through a pipeline, and the exhaust gas outlet of the 3rd section of the ring cooler is connected to the inlet end of the fan (6) of the 1st section of the ring cooler through a pipeline.

2. According to claim 1, a highly efficient and environmentally friendly sinter cooler waste heat recovery power generation system is characterized by: When the sintered ore cooler has 5 stages, the flue gas temperature of the first stage of the ring cooler is 470-510°C, the flue gas temperature of the second stage of the ring cooler is 300-350°C, the exhaust gas temperature of the third stage of the ring cooler is 200-230°C, the exhaust gas temperature of the fourth stage of the ring cooler is 130-163°C, the exhaust gas temperature of the fifth stage of the ring cooler is 70-90°C, and the lower circulating exhaust gas temperature of the low-temperature combined waste heat boiler is 150°C.

3. The efficient and environmentally friendly sinter cooler waste heat recovery power generation system according to claim 1 is characterized in that: The working pressure of the waste heat boiler is 3.0-3.5 MPa.

4. The efficient and environmentally friendly sinter cooler waste heat recovery power generation system according to claim 1 is characterized in that: The organic working fluid of the ORC power generation system (2) is R245fa.

5. The efficient and environmentally friendly sinter cooler waste heat recovery power generation system according to any one of claims 1 to 4, characterized in that: A waste heat boiler induced draft fan (7) is installed on the pipeline at the bottom of the shell side of the organic working medium heat exchanger (3).

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