Total energy recovery belt type roasting machine process air circulation system

Abstract

The invention relates to the technical field of pellet roasting of belt type roasting machines, in particular to a total energy recovery belt type roasting machine process air circulation system. A forced air drying section communicates with a second cooling section through a first process air pipeline, and a heat exchanger and a first cooling circulating fan are arranged on the first process air pipeline; the roasting section and the soaking section are communicated with a second process air pipeline, the second process air pipeline partially passes through the heat exchanger, a backheating fan is arranged on the second process air pipeline, and a first branch pipeline and a second branch pipeline are arranged on one side, at the outlet end of the heat exchanger, of the second process air pipeline; one end of the first branch pipeline is communicated with the second process air pipeline, the opposite other end of the first branch pipeline is communicated with the first cooling section, and a second cooling circulating fan is arranged on the first branch pipeline; one end of the second branch pipeline is communicated with the second process air pipeline, and the opposite other end of the second branch pipeline is communicated with the air draft drying section and / or the first preheating section and / or the second preheating section. The fuel consumption and the cost are reduced by utilizing the system flue gas sensible heat.

Description

Technical Field

[0001] The present disclosure relates to the technical field of pellet roasting in a belt roaster, and in particular to a process air circulation system for a belt roaster with full energy recovery. Background Art

[0002] The belt roaster pelletizing technology is developing rapidly. Compared with sintering, chain-return-loop, and shaft furnace iron ore agglomeration technology, it has obvious advantages in energy saving, consumption reduction, and quality improvement. With the development and innovation of technology, the requirements in the metallurgical field are becoming more and more stringent. For the utilization of waste heat from the process wind and flue gas of the belt roaster pelletizing technology, further reducing fuel consumption, reducing carbon emissions, improving the quality of pellets, and better utilizing low calorific value coal gas have become urgent issues to be solved. Summary of the invention

[0003] The present disclosure aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, the present disclosure provides a full energy recovery belt roasting machine process air circulation system, including a belt roasting furnace body, wherein the belt roasting furnace body includes a blast drying section, an exhaust drying section, a first preheating section, a second preheating section, a roasting section, a soaking section, a first cooling section, a second cooling section and a third cooling section arranged in sequence, wherein:

[0005] The blast drying section is connected to the second cooling section through a first process air duct, a heat exchanger and a first cooling circulation fan are arranged on the first process air duct, and the first cooling circulation fan is used to input the process air after heat exchange by the heat exchanger into the second cooling section;

[0006] The roasting section and the soaking section are connected to a second process air pipeline, a portion of the second process air pipeline passes through the heat exchanger, and a heat recovery fan is provided on the second process air pipeline, the heat recovery fan is used to exert a force for the process air to flow from the inlet side to the outlet side of the second process air pipeline, and the second process air pipeline is provided with a first branch pipeline and a second branch pipeline on one side of the outlet end of the heat exchanger;

[0007] One end of the first branch pipeline is connected to the second process air pipeline, and the other end thereof is connected to the first cooling section, and a second cooling circulation fan is provided on the first branch pipeline, and the second cooling circulation fan is used to exert a force on the process air of the second process pipeline after heat exchange to flow from the inlet side to the outlet side of the first branch pipeline;

[0008] One end of the second branch pipeline is connected to the second process air pipeline, and the other end thereof is connected to the exhaust drying section and / or the first preheating section and / or the second preheating section.

[0009] In a feasible embodiment, a first bypass pipeline is arranged on the first process air duct, and the first bypass pipeline has a first inlet end and a first outlet end, the first inlet end is connected to the first process air duct on the inlet side of the heat exchanger, and the outlet end is connected to the first process air duct on the outlet side of the heat exchanger.

[0010] In a feasible implementation manner, a first stop valve is provided on the first bypass pipeline.

[0011] In a feasible implementation manner, the first stop valve is configured as an electric high-temperature butterfly valve.

[0012] In a feasible implementation manner, the third cooling section is connected to the blast drying section via a third process air duct, and a dry blower is provided on the third process air duct, and the dry blower is used to apply a force of the process air flow of the third cooling section to the blast drying section.

[0013] In a feasible embodiment, it also includes a second bypass pipeline, which has a second inlet end and a second outlet end, the second inlet end is connected to the side of the third process air pipeline close to the blast drying section, and the outlet end is connected to the side of the first process air pipeline close to the blast drying section.

[0014] In a feasible implementation manner, a second stop valve is provided on the second bypass pipeline, and the stop valve is close to the second inlet end.

[0015] In a feasible implementation manner, the second stop valve is configured as an electric high-temperature butterfly valve.

[0016] In a feasible embodiment, it also includes a desulfurization and denitrification pipeline, the inlet of which is connected to the first preheating section, the second preheating section and the exhaust drying section, and an electrostatic precipitator and a main induced draft fan are arranged on the desulfurization and denitrification pipeline, and the electrostatic precipitator is arranged on a side close to the inlet of the desulfurization and denitrification pipeline.

[0017] In a feasible implementation manner, a cooling air valve is provided between the main induced draft fan and the electrostatic precipitator.

[0018] The above description is only an overview of the technical solution provided by the present disclosure. In order to more clearly understand the technical means of the present disclosure, it can be implemented according to the contents of the specification. In order to make the above and other features and effects of the present disclosure more obvious and easy to understand, the implementation methods of the present disclosure are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the exemplary embodiments below. The accompanying drawings are only for the purpose of illustrating exemplary embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0022] Figure 1 It is a schematic diagram of the structure of the present invention.

[0023] in, Figure 1 The corresponding relationship between the reference numerals and the component names is as follows:

[0024] 100-first process air pipeline; 101-first bypass pipeline; 200-second process air pipeline; 201-first branch pipeline; 202-second branch pipeline; 300-third process air pipeline; 400-second bypass pipeline; 401-second stop valve;

[0025] 2-blast drying section; 3-exhaust drying section; 4-first preheating section; 5-second preheating section; 6-roasting section; 7-heating section; 8-first cooling section; 9-second cooling section; 10-third cooling section; 11-main induced draft fan; 12-heat recovery fan; 13-dry blower; 14-cooling fan; 15-second cooling circulation fan; 16-first cooling circulation fan; 17-heat exchanger; 18-cold air valve; 19-first stop valve; 20-electrostatic precipitator. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0028] At present, the belt roaster pelletizing technology is developing rapidly. Compared with sintering, chain-return-loop, and shaft furnace iron ore agglomeration technology, it has obvious advantages in energy saving, consumption reduction, and quality improvement. With the development and innovation of technology, the requirements in the metallurgical field are becoming more and more stringent. For the utilization of waste heat from the process wind and flue gas of the belt roaster pelletizing technology, further reducing fuel consumption, reducing carbon emissions, improving the quality of pellets, and better utilizing low calorific value coal gas have become urgent issues to be solved.

[0029] Based on this, the embodiment of the present disclosure provides a full energy recovery full energy recovery belt roasting machine process air circulation system, the package of the forced air drying section is connected to the second cooling section through the first process air duct, the first process air duct is provided with a heat exchanger and a first cooling circulation fan; the roasting section and the equalizing section are connected to the second process air duct, the second process air duct part passes through the heat exchanger, and the second process air duct is provided with a heat recovery fan, and the second process air duct is provided with a first branch pipeline and a second branch pipeline on one side of the heat exchanger outlet end; one end of the first branch pipeline is connected to the second process air duct, and the other end is connected to the first cooling section, and the first branch pipeline is provided with a second cooling circulation fan; one end of the second branch pipeline is connected to the second process air duct, and the other end is connected to the exhaust drying section and / or the first preheating section and / or the second preheating section. The present disclosure uses the sensible heat of the system flue gas to reduce fuel consumption and cost.

[0030] The full energy recovery full energy recovery belt roasting machine process air circulation system is described in detail below through a specific embodiment:

[0031] Reference Figure 1As shown, the present disclosure provides a full energy recovery belt roasting machine process air circulation system, including a belt roasting furnace body, the belt roasting furnace body includes a blast drying section 2, an exhaust drying section 3, a first preheating section 4, a second preheating section 5, a roasting section 6, a soaking section 7, a first cooling section 8, a second cooling section 9 and a third cooling section 10 arranged in sequence, the blast drying section 2 is connected to the second cooling section 9 through a first process air duct 100, a heat exchanger 17 and a first cooling circulation fan 16 are provided on the first process air duct 100, and the first cooling circulation fan 16 is used to input the process air after heat exchange by the heat exchanger 17 into the second cooling section 9; the roasting section 6 and the soaking section 7 are connected to the second process air duct 200, a part of the second process air duct 200 passes through the heat exchanger 17, and the second process air duct 200 has a heat exchanger 17 and a first cooling circulation fan 16 on the first process air duct 200. A heat recovery fan 12 is provided, and the heat recovery fan 12 is used to apply a force to the process air to flow from the inlet side to the outlet side of the second process pipeline. The second process air pipeline 200 is provided with a first branch pipeline 201 and a second branch pipeline 202 on one side of the outlet end of the heat exchanger 17; one end of the first branch pipeline is connected to the second process air pipeline 200, and the other end is connected to the first cooling section 8, and a second cooling circulation fan 15 is provided on the first branch pipeline 201, and the second cooling circulation fan 15 is used to apply a force to the process air of the second process pipeline after heat exchange to flow from the inlet side to the outlet side of the first branch pipeline 201; one end of the second branch pipeline 202 is connected to the second process air pipeline 200, and the other end is connected to the exhaust drying section 3 and / or the first preheating section 4 and / or the second preheating section 5.

[0032] The present invention innovatively changes the traditional seven process sections into nine process sections, namely, forced air drying section 2, exhaust air drying section 3, first preheating section 4, second preheating section 5, roasting section 6, equalizing section 7, first cooling section 8, second cooling section 9, and third cooling section 10, wherein the second preheating section 5 and the third cooling section 10 are newly added process sections, the outlet flue gas temperature of the first cooling section 8 is 950°C to 1100°C, and is circulated to the equalizing section 7 through the smoke hood of the first cooling section 8, which is the heat source of the equalizing section 7. According to the characteristics and functional requirements of each process section, different process means and measures are adopted to utilize the sensible heat of the system flue gas and the use of low calorific value gas as much as possible to reduce fuel consumption and cost.

[0033] Specifically, the temperature of the first preheating section 4 is set to 450°C to 650°C, and low calorific value gas, i.e. converter gas with a calorific value of about 1400 kcal / Nm3, can be used as fuel to reduce the use of high calorific value gas, thereby reducing fuel costs.

[0034] The temperature of the second preheating section 5 is set to 700°C to 1150°C, and the temperature of the roasting section 6 is set to 1200°C to 1250°C. The required temperature is relatively high, and a mixed gas of natural gas and converter gas can be used, and its calorific value is ≥1850kcal / Nm3 As fuel, add as much converter gas as possible to reduce fuel costs.

[0035] The outlet flue gas temperature of the blast drying section 2 disclosed in the present invention is 70°C to 120°C. The previous external discharge method is changed to being connected to the second cooling section 9 through the first process air duct 100 without external discharge. The hot air circulated to the tail and the outlet temperature of the heat recovery fan 12 is 330°C to 420°C. The hot air at the outlet of the blast drying section 2 is heated from 70°C to 120°C to 150°C to 200°C through the heat exchanger 17. The 900°C to 550°C hot ball in the second cooling section 9 is blown into the cooling through the first cooling circulation fan 16 for use as cooling air. The system fully recovers energy, utilizes the sensible heat of the flue gas as much as possible, and reduces fuel consumption.

[0036] The hot air temperature of the roasting section 6 and the equalizing section 7 output through the second process air duct 200 and the outlet of the heat recovery fan 12 is 330℃ to 420℃. The hot air is heat-exchanged with the flue gas with an outlet temperature of 70℃ to 120℃ in the blast drying section 2 in the first process air duct 100 to 250℃ to 350℃ through the heat exchanger 17. Among them, a part of the process air after heat exchange enters the first cooling section 8 through the first branch pipeline 201, and is used as the hot ball cooling air with a temperature of 1000℃ to 1150℃ in the first cooling section 8, and a part of the circulating belt roasting machine head part can be divided into three routes through the second branch pipeline 202, one route is sent to the exhaust drying section 3 as a heat source; one route is sent to the first preheating section 4 for preheating the burner air temperature and adjusting the smoke hood smoke temperature; one route is sent to the second preheating section 5 for preheating the burner air temperature and adjusting the smoke hood smoke temperature. Electric high-temperature butterfly valves are provided on the three pipelines to adjust the smoke volume.

[0037] Specifically, through the process air circulation system disclosed in the present invention, the hot air from the outlet of the heat recovery blower 12 is used as the hot ball cooling air in the first cooling section 8 and the hot air from the blast drying section 2 is used as the hot ball cooling air in the second cooling section 9, which can reduce the rapid cooling brittle effect of the hot pellets and increase the compressive strength of the finished pellets by about 150 to 250 N / P; the process air hot air is used to replace a part of the ambient cold air blown by the cooling blower 14, which can reduce the system exhaust flue gas baseline oxygen content by 0.5% to 0.8%; at the same time, the hot air system is used to circulate into the large smoke hood to reduce the amount of cold air entering, fully recover energy, and maximize the use of system energy, which can reduce fuel consumption by about 5% to 8%.

[0038] In some embodiments, a first bypass pipeline 101 is provided on the first process air pipeline 100 of the present disclosure, and the first bypass pipeline 101 has a first inlet end and a first outlet end. The first inlet end is connected to the first process air pipeline 100 on the inlet side of the heat exchanger 17, and the outlet end is connected to the first process air pipeline 100 on the outlet side of the heat exchanger 17.

[0039] In this embodiment, the first bypass pipeline 101 can be used as a maintenance pipeline for the heat exchanger, and can also play a role in pressure relief and decompression during the operation of the first process air pipeline 100, thereby improving the stability and safety of the system. Further, a first stop valve 19 is provided on the first bypass pipeline 101 to realize the opening and closing of the first bypass pipeline 101. The first stop valve 19 can be set as a manual valve or an electric valve. The present disclosure specifically sets the first stop valve 19 as an electric high-temperature butterfly valve. As a component used to realize the on-off and flow control of the pipeline system, the high-temperature butterfly valve mostly adopts a sealing structure in the form of sealing, and the sealing material is rubber, polytetrafluoroethylene, etc. Specifically, a three-eccentric metal hard seal butterfly valve can be selected, the valve body and the valve seat are a connected component, and the valve seat sealing surface layer is welded with a heat-resistant and corrosion-resistant alloy material. A multi-layer soft stacking seal ring is fixed on the valve plate. Compared with the traditional butterfly valve, this butterfly valve has the advantages of high temperature resistance, easy operation, no friction when opening and closing, and the seal is compensated as the torque of the transmission mechanism increases when closing, which improves the sealing performance of the butterfly valve and prolongs the service life.

[0040] In this embodiment, the third cooling section 10 of the present invention is connected to the blast drying section 2 through the third process air duct 300. A blast drying blower 13 is provided on the third process air duct 300. The blast drying blower 13 is used to apply a force of the process air of the third cooling section 10 to the blast drying section 2, and lead the waste flue gas from the third cooling section to the blast drying section 2 as a heat source (temperature 250°C ~ 350°C) to dry the raw balls.

[0041] In this embodiment, a second bypass pipeline 400 is also included. The second bypass pipeline 400 has a second inlet end and a second outlet end. The second inlet end is connected to the third process air pipeline 300, which is close to the inlet bellows of the blast drying section 2, and the outlet end is connected to the first process air pipeline 100, which is close to the outlet smoke hood of the blast drying section 2. The first function is to prevent the third process air pipeline 300 from having too much flue gas by opening the second stop valve 401 and passing through the second bypass pipeline 400 to directly enter the first process air pipeline 100 across the ball layer, so as to prevent excessive positive pressure from occurring on the lower side of the ball layer of the blast drying section 2 and flue gas overflowing. The second function is to adjust the second stop valve 401 to add hot flue gas with a temperature of 250°C to 350°C into the flue gas (temperature 70°C to 100°C) in the first process air pipeline 100 when the flue gas temperature is too low in winter, so as to prevent condensation of water vapor in the flue gas of the first process air pipeline 100.

[0042] In this embodiment, the second bypass pipeline 400 can be used as a maintenance pipeline for the first process air pipeline 100 and the third process air pipeline 300, and can also play a role in pressure relief and pressure reduction during the operation of the first process air pipeline 100 and the third process air pipeline 300, thereby improving system stability and safety. Further, a second stop valve 401 is provided on the second bypass pipeline 400, and the second stop valve 401 is close to the second inlet end, and the second stop valve 401 is set as an electric high-temperature butterfly valve.

[0043] In some embodiments, it also includes a desulfurization and denitrification pipeline, the inlet of which is connected to the first preheating section 4, the second preheating section 5 and the exhaust drying section 3, and an electrostatic precipitator 20 and a main induced draft fan 11 are arranged on the desulfurization and denitrification pipeline, and the electrostatic precipitator 20 is arranged on the side close to the inlet of the desulfurization and denitrification pipeline.

[0044] In some embodiments, a cold air valve 18 is provided between the main induced draft fan 11 and the electrostatic precipitator 20. The cold air valve is driven by a rack. Before opening, the pressure difference on both sides is large, so it must be equalized first. This can also effectively avoid the violent fluctuation of the blast furnace air pressure. There is a small equalizing valve on the main valve, which is opened before the main valve is opened. After the hot blast furnace is slowly filled with cold air, the main valve is opened to complete the operation.

[0045] In the present disclosure, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0046] In the description of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be understood as a limitation on the present disclosure.

[0047] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0048] The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A full energy recovery belt roasting machine process air circulation system, characterized in that: The belt roasting furnace body includes a blast drying section, an exhaust drying section, a first preheating section, a second preheating section, a roasting section, a soaking section, a first cooling section, a second cooling section and a third cooling section arranged in sequence, wherein: The blast drying section is connected to the second cooling section through a first process air duct, a heat exchanger and a first cooling circulation fan are arranged on the first process air duct, and the first cooling circulation fan is used to input the process air after heat exchange by the heat exchanger into the second cooling section; The roasting section and the soaking section are connected to a second process air pipeline, a portion of the second process air pipeline passes through the heat exchanger, and a heat recovery fan is provided on the second process air pipeline, the heat recovery fan is used to exert a force for the process air to flow from the inlet side to the outlet side of the second process air pipeline, and the second process air pipeline is provided with a first branch pipeline and a second branch pipeline on one side of the outlet end of the heat exchanger; One end of the first branch pipeline is connected to the second process air pipeline, and the other end thereof is connected to the first cooling section, and a second cooling circulation fan is provided on the first branch pipeline, and the second cooling circulation fan is used to exert a force on the process air of the second process pipeline after heat exchange to flow from the inlet side to the outlet side of the first branch pipeline; One end of the second branch pipeline is connected to the second process air pipeline, and the other end thereof is connected to the exhaust drying section and / or the first preheating section and / or the second preheating section.

2. The full energy recovery belt roasting machine process air circulation system according to claim 1 is characterized in that: A first bypass pipeline is arranged on the first process air duct, and the first bypass pipeline has a first inlet end and a first outlet end, the first inlet end is connected to the first process air duct on the inlet side of the heat exchanger, and the outlet end is connected to the first process air duct on the outlet side of the heat exchanger.

3. The full energy recovery belt roasting machine process air circulation system according to claim 2 is characterized in that: The first bypass pipeline is provided with a first stop valve.

4. The full energy recovery belt roasting machine process air circulation system according to claim 3 is characterized in that: The first stop valve is configured as an electric high-temperature butterfly valve.

5. The full energy recovery belt roasting machine process air circulation system according to claim 1 is characterized in that: The third cooling section is connected to the blast drying section through a third process air duct, and a dry blower is provided on the third process air duct. The dry blower is used to apply a force of the process air of the third cooling section to the blast drying section.

6. The full energy recovery belt roaster process air circulation system according to claim 1 is characterized in that: It also includes a second bypass pipeline, which has a second inlet end and a second outlet end. The second inlet end is connected to the side of the third process air pipeline close to the blast drying section, and the outlet end is connected to the side of the first process air pipeline close to the blast drying section.

7. The full energy recovery belt roasting machine process air circulation system according to claim 6 is characterized in that: The second bypass pipeline is provided with a second stop valve, and the stop valve is close to the second inlet end.

8. The full energy recovery belt roasting machine process air circulation system according to claim 7 is characterized in that: The second stop valve is configured as an electric high-temperature butterfly valve.

9. The full energy recovery belt roaster process air circulation system according to claim 1 is characterized in that: It also includes a desulfurization and denitrification pipeline, the inlet of which is connected to the first preheating section, the second preheating section and the exhaust drying section. An electrostatic precipitator and a main induced draft fan are arranged on the desulfurization and denitrification pipeline, and the electrostatic precipitator is arranged on a side close to the inlet of the desulfurization and denitrification pipeline.

10. The full energy recovery belt roasting machine process air circulation system according to claim 9, characterized in that: A cooling air valve is arranged between the main induced draft fan and the electrostatic precipitator.

Images