Comprehensive utilization and zero emission process for waste heat of exhaust gas of sintering circular cooler

Abstract

The invention provides a sintering circular cooler waste gas waste heat comprehensive utilization zero emission technology, and relates to the technical field of metallurgy. The sintering circular cooler waste gas waste heat comprehensive utilization zero emission technology comprises the steps that S1, a circular cooling part is divided into five sections; s2, high-temperature hot waste gas of the first section and the second section is conveyed to a waste heat boiler for waste heat power generation; s3, the hot waste gas of the third section is used for hot air ignition or hot air sintering; s4, hot waste gas of the fourth section is used for producing hot water; and S5, hot waste gas of the fifth section is introduced into the annular cooler, all annular cooling waste heat is utilized, the high-temperature section generates power, the low-temperature section is used for hot air sintering, hot water is generated to improve the temperature of a sintering mixture, waste heat is fully utilized, the annular cooler is divided into five sections, and all utilization and zero emission are achieved according to reasonable utilization of the flue gas temperature and the flue gas amount of each section. And the method has remarkable economic benefits and social benefits.

Description

Technical Field

[0001] The present application relates to the field of metallurgical technology, and in particular to a zero-emission process for comprehensive utilization of waste heat from exhaust gas from a sintering ring cooler. Background Art

[0002] The sintering ring cooler, also known as the ring cooler, is one of the main equipment in the sintering system engineering. It is mainly used to quickly cool high-temperature sintered ore. During cooling, the sintered ore (750℃~850℃) is evenly distributed on the ring cooler trolley. After being cooled by the ring cooler, the sintered ore discharge temperature is ≤120℃. Then it is unloaded to the finished product belt (the belt has a heat resistance temperature of 200℃) through a heavy tank chain plate feeder. The sintered ore cooling adopts a multifunctional and efficient blast ring cooler with an efficient sealing structure, in which a water sealing device is set between the ring cooler rotor and the bellows. The ring cooling cover is fully sealed, and a water seal is used between the sealing cover and the trolley. The trolley railings are insulated to reduce power consumption and improve the utilization efficiency of waste heat from exhaust gas.

[0003] At present, for the utilization of waste heat from exhaust gas of sintering ring coolers, the flue gas from both high-temperature and low-temperature sections of the ring cooler is usually used for power generation, and the exhaust gas after power generation is discharged externally. However, in fact, only a small amount of exhaust gas from the low-temperature section of the ring cooler can be used for power generation, and most of it cannot be used for power generation. Not only is the waste heat not fully utilized, but also zero emission utilization of exhaust gas cannot be achieved.

[0004] In view of this, the present application aims to provide a zero-emission process for comprehensive utilization of waste heat from exhaust gas from a sintering ring cooler to better solve the above-mentioned technical problems. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a zero-emission process for comprehensive utilization of waste heat from exhaust gas from a sintering ring cooler, which achieves the cooling effect of sintered ore while making full use of the waste heat for power generation and production applications, and realizes "zero" flue gas emissions, which is of great significance to sintering energy conservation and emission reduction.

[0006] The present application provides a zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas, including the following steps:

[0007] S1. Divide the cooling part of the cooling machine into 5 sections according to the temperature from high to low;

[0008] S2. The hot exhaust gas from the first and second sections is sent to the waste heat boiler for waste heat power generation, and the hot exhaust gas after waste heat utilization is returned to the ring cooler;

[0009] S3. The hot exhaust gas from the third section is introduced into the combustion-supporting fan for hot air ignition, or the hot exhaust gas from the third section is delivered to the sintering machine material surface by unpowered conveying for use as hot air sintering;

[0010] S4. The hot exhaust gas in the fourth section is used to produce hot water, and the hot exhaust gas after waste heat utilization is returned to the ring cooler;

[0011] S5. Connect the hot exhaust gas from the 5th section to the ring cooler to achieve "zero" flue gas emissions.

[0012] Furthermore, in step S1, 5 blowers are provided corresponding to the 5 sections into which the ring cooler is divided, mufflers and damper regulating valves are provided at the inlets of the 5 blowers, and a diaphragm coupling is used between each blower and the motor, the bearing at the heavy vehicle end of the blower is designed to be disassembled and installed from the light vehicle end, and the blowers and motors are provided with necessary detection devices.

[0013] Furthermore, blowers No. 3 and No. 5 are configured as variable frequency speed regulating blowers.

[0014] Furthermore, in step S2, the hot exhaust gas sent to the waste heat boiler is used to generate steam, and the generated steam is sent to the steam-supplemented condensing steam turbine generator set for waste heat power generation, so that the exhaust temperature of the waste heat boiler is less than 140°C, and the exhaust gas of the waste heat boiler is introduced into the cooling bellows of the ring cooler through the circulating fan, and a valve is set before the return air duct enters the bellows, and ash discharge ports are set on both sides of the valve, and the circulating fan adopts frequency conversion regulation.

[0015] Furthermore, a set of switching damper doors are respectively provided at the flue gas inlet and outlet systems of the waste heat boiler to facilitate isolation of the waste heat recovery system at any time when a failure occurs.

[0016] Specifically, the waste heat boiler adopts a double-pressure waste heat boiler structure, and is arranged vertically under the ring cooler and circulates naturally. The boiler has its own deaerator. The boiler body includes various heating surface tube groups, boiler steel frame and flue shell module, platform escalator, high-parameter boiler drum, and low-parameter boiler drum.

[0017] Specifically,

[0018] The exhaust gas temperature of waste heat boiler should be less than 140℃;

[0019] The pressure drop of the waste heat boiler body is less than 1100Pa;

[0020] The outer surface temperature of the smoke and air duct of the flue gas system is greater than 50℃, and the smoke and air duct that needs to reduce heat dissipation loss must be insulated; the smoke and air duct that does not need insulation during process production but has an outer wall temperature exceeding 60℃ and other measures cannot be taken to prevent scalding of personnel must be insulated.

[0021] In order to adapt to different sintering conditions, the boiler feed pump is equipped with frequency conversion regulation function.

[0022] Specifically, when waste heat is used for power generation, the exhaust gas from the first section of the ring cooler is led to the superheater and the first-stage medium-pressure evaporator on the top of the waste heat boiler through the air duct. The exhaust gas from the second section is mixed with the flue gas from the first section after heat exchange through the superheater and the first-stage medium-pressure evaporator. The mixed exhaust gas all enters the second-stage medium-pressure evaporator of the waste heat boiler, and then enters the economizer, low-pressure evaporator and condensate heater of the waste heat boiler in sequence. The exhaust gas temperature is less than 140°C. The exhaust gas from the waste heat boiler is introduced into the cooling bellows of the ring cooler through the circulating fan. A valve is set before the return air duct enters the bellows, and ash discharge ports are set on both sides of the valve.

[0023] In addition, when the sintering machine is overloaded and the flue gas temperature is too high, the flue gas temperature can be lowered by adjusting the opening of the 1# and 2# chimney damper doors of the ring cooler to appropriately add cold air.

[0024] Furthermore, in step S3, the hot exhaust gas from the third section is introduced to the combustion-supporting blower after multi-tube dust removal to increase the combustion-supporting air temperature of the sintering machine ignition furnace to a temperature ≥ 200°C, thereby achieving hot air ignition.

[0025] Furthermore, in step S3, the hot exhaust gas of the third section is sent to the material surface of the sintering trolley through the hot air duct via the ring cooling blower to achieve hot air sintering.

[0026] Furthermore, a manual inspection door is provided on the hot air duct, and an ash unloading funnel is provided at the dust accumulation position of the hot air duct. The outer surface of the hot air duct is insulated with a heat-insulating material with a thickness of 100 mm. At the same time, an electric regulating valve is provided on the hot air duct.

[0027] Furthermore, in step S4, the hot exhaust gas of the fourth section produces hot water through the hot water exchanger, and the exhaust gas flowing out of the hot water exchanger is sent to the air inlet of the No. 4 blower and enters the ring cooler to realize the self-circulation of this section of exhaust gas.

[0028] Specifically, in the hot waste gas hot water production link of the 4th section, a hot water exchanger, 2 sets of cold water pumps, a cold water tank, and supporting regulating control valves and pipelines are set. When the waste heat of the exhaust gas is utilized, the industrial cold water supplied by the water tank is heated. At the same time, water temperature detection and water volume regulating valves are set to realize automatic control of the water temperature of the heat exchanger (≥85℃). At the same time, the water tank is connected to the industrial water and external network steam (from the waste heat power generation project) heating pipe to realize the steam hot water function. In addition, a bypass pipe is set for the hot water exchanger to ensure stable water addition when the hot water exchanger fails. At the same time, an insulation layer is laid on the hot water delivery pipe, and a water level detection structure is set in the water tank. It has local and remote display to realize automatic water replenishment function.

[0029] Furthermore, in step S4, the hot exhaust gas from the 5th section is connected to the air inlet of the No. 3 blower and enters the ring cooler to achieve "zero" flue gas emissions.

[0030] Beneficial effects of the present invention:

[0031] The zero-emission process for comprehensive utilization of waste heat of sintering ring cooler waste gas provided by the present invention comprises the following steps: S1. dividing the ring cooling part of the ring cooler into 5 sections in order from high to low temperature; S2. sending the hot waste gas of the first section and the second section to the waste heat boiler for waste heat power generation, and returning the hot waste gas after waste heat utilization to the ring cooler; S3. introducing the hot waste gas of the third section into the combustion-supporting fan for hot air ignition, or sending the hot waste gas of the third section to the sintering machine material surface by non-powered conveying mode for use as hot air sintering; S4. using the hot waste gas of the fourth section to produce hot water, and returning the hot waste gas after waste heat utilization to the ring cooler; S5. The hot exhaust gas from the 5th section is connected to the ring cooler to achieve "zero" flue gas emissions. All the waste heat from the ring cooler is fully utilized. The high-temperature section generates electricity, and the low-temperature section is used for hot air sintering and generating hot water to increase the temperature of the sintered mixture. The waste heat is fully utilized. By dividing the ring cooler into 5 sections, the flue gas temperature and volume of each section are reasonably utilized to achieve full utilization and zero emissions. After testing, the process provided by the present invention can increase the power generation per ton of sintered ore by 3 to 5 degrees, reduce the energy consumption of the sintering process by 2 to 3kgce / t, and increase the sintering output by 5 to 10%, which has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application 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 paying creative work.

[0033] Figure 1 It is a process flow chart in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, 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 part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0037] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", 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 application is usually placed when in use. They are only for the convenience of describing the present application 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 a limitation on the present application. 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.

[0038] 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.

[0039] In the description of this application, it should also be noted 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 this application can be understood according to specific circumstances.

[0040] See also Figure 1 As shown, the zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas described in this embodiment includes the following steps:

[0041] S1. The cooling part of the ring cooler is divided into 5 sections according to the temperature from high to low. Five blowers are set corresponding to the 5 temperature ends of the ring cooler. The inlets of the 5 blowers are equipped with mufflers and damper regulating valves. A diaphragm coupling is used between each blower and the motor. The heavy vehicle end bearing of the blower is designed to be disassembled and installed from the light vehicle end. The blower and motor are equipped with necessary detection devices. Blowers No. 3 and No. 5 are set as variable frequency speed regulating blowers.

[0042] S2. The hot exhaust gas from the first and second sections is sent to the waste heat boiler for waste heat power generation, and the hot exhaust gas after waste heat utilization is returned to the ring cooler;

[0043] Specifically, the waste heat boiler adopts a double-pressure waste heat boiler structure, and is arranged vertically under the ring cooler and naturally circulates. The boiler is equipped with a deaerator. The boiler body includes various heating surface tube groups, boiler steel frame and flue shell modules, platform escalator, high-parameter drum, and low-parameter drum. In addition, a set of switching damper doors are respectively set at the inlet and outlet flue gas systems of the waste heat boiler to facilitate isolation at any time when the waste heat recovery system fails;

[0044] Specifically, the exhaust gas temperature of the waste heat boiler should be less than 140℃; the pressure drop of the waste heat boiler body should be less than 1100Pa; the outer surface temperature of the smoke and air duct of the flue gas system should be greater than 50℃, and the smoke and air duct that needs to reduce heat dissipation loss must be insulated; the smoke and air duct that does not need to be insulated during process production but has an outer wall temperature of more than 60℃ and cannot take other measures to prevent scalding personnel must be insulated; in order to adapt to different sintering conditions, the boiler feed water pump is equipped with a frequency conversion adjustment function;

[0045] Specifically, the waste heat exhaust gas from the first and second sections is sent to the waste heat boiler to generate steam, and the generated steam is sent to the steam-assisted condensing steam turbine generator set for waste heat power generation, so that the exhaust temperature of the waste heat boiler is less than 140°C, and the exhaust gas of the waste heat boiler is introduced into the cooling wind box of the ring cooler through the circulating fan, and a valve is set before the return air duct enters the wind box, and ash discharge ports are set on both sides of the valve, wherein the circulating fan adopts frequency conversion regulation;

[0046] When waste heat is used for power generation, the exhaust gas from the first section of the ring cooler is led to the superheater and the first-stage medium-pressure evaporator on the upper part of the waste heat boiler through the air duct. The exhaust gas from the second section is mixed with the flue gas from the first section after heat exchange through the superheater and the first-stage medium-pressure evaporator. The mixed exhaust gas all enters the second-stage medium-pressure evaporator of the waste heat boiler, and then enters the economizer, low-pressure evaporator and condensate heater of the waste heat boiler in sequence. The exhaust gas temperature is less than 140°C. The exhaust gas from the waste heat boiler is introduced into the cooling bellows of the ring cooler through the circulating fan. A valve is set before the return air duct enters the bellows, and ash discharge ports are set on both sides of the valve.

[0047] In addition, when the sintering machine is overloaded and the flue gas temperature is too high, the flue gas temperature can be reduced by adjusting the opening of the damper doors of the 1# and 2# chimneys of the ring cooler and appropriately adding cold air;

[0048] S3. The hot exhaust gas from the third section is led to the combustion-supporting fan after multi-tube dust removal to increase the combustion-supporting air temperature of the sintering machine ignition furnace to ≥200°C to achieve hot air ignition; or the hot exhaust gas from the third section is sent to the sintering trolley material surface through the hot air duct through the ring cooling blower to achieve hot air sintering. In addition, it is necessary to set a manual maintenance door on the hot air duct, and set an ash unloading funnel at the dust accumulation part of the hot air duct. The outer surface of the hot air duct is insulated with insulation material with a thickness of 100mm, and an electric regulating valve is set on the hot air duct;

[0049] S4. The hot exhaust gas of the fourth section is passed through the hot water exchanger to produce hot water, and the exhaust gas flowing out of the hot water exchanger is sent to the air inlet of the No. 4 blower and enters the ring cooler to realize the self-circulation of the exhaust gas of this section;

[0050] Specifically, in the hot waste gas hot water production link of the fourth section, a hot water exchanger, two sets of cold water pumps, a cold water tank, and supporting regulating control valves and pipelines are set. When the waste heat of the waste gas is utilized, the industrial cold water supplied by the water tank is heated, and water temperature detection and water volume regulating valves are set to realize automatic control of the water temperature of the heat exchanger (≥85°C). At the same time, the water tank is connected to the industrial water and external network steam (from the waste heat power generation project) heating pipe to realize the steam hot water function. In addition, a bypass pipeline is set for the hot water exchanger to ensure stable water addition when the hot water exchanger fails. At the same time, an insulation layer is laid on the hot water delivery pipe, and a water level detection structure is set in the water tank, and it has local and remote display to realize the automatic water replenishment function;

[0051] S5. Connect the hot exhaust gas from the 5th section to the ring cooler to achieve "zero" flue gas emissions.

[0052] Specifically, in this embodiment, the ring cooler is 280m 2 Multifunctional and efficient ring cooler, trolley width 3500mm; trolley railing height 1600mm; center diameter 30000mm, main parameters of ring cooler:

[0053] ①Effective cooling area: 2×280m 2 ;

[0054] ②Maximum processing capacity: 535t / h;

[0055] ③Discharge temperature: average temperature ≤120℃.

[0056] Specifically, in this embodiment, the original design parameters of the hot air resources of the ring cooler used for sintering waste heat power generation are as follows:

[0057] Serial number Parameter name unit Rated operating conditions 1 Gas flow rate <![CDATA[Nm 3 / h]]> 190000 2 Second stage gas flow <![CDATA[Nm 3 / h]]> 190000 3 Average gas temperature ℃ 400 4 Average gas temperature of the second stage ℃ 300

[0058] According to tests, compared with the prior art, the waste heat utilization process provided in this embodiment can increase the power generation per ton of sintered ore by 3 to 5 degrees, reduce the energy consumption of the sintering process by 2 to 3 kgce / t, and increase the sintering output by 5 to 10%, which has significant economic and social benefits.

[0059] To summarize, the recycling process provided by the present application divides the ring cooler into five sections and reasonably utilizes the flue gas temperature and volume of each section to achieve full utilization and zero emissions. The waste heat from the ring cooling is fully utilized. The high-temperature section is used for power generation, and the low-temperature section is used for hot air sintering and to generate hot water to increase the temperature of the sintered mixture. The waste heat is fully utilized. The present application utilizes the waste heat from the ring cooling in a scientific and reasonable manner, achieves the cooling effect of the sintered ore, and at the same time fully utilizes the waste heat for power generation and production applications, and realizes "zero" flue gas emissions, which is of great significance to energy conservation and emission reduction in sintering.

[0060] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas, characterized in that: The following steps are involved: S1. Divide the cooling part of the cooling machine into 5 sections according to the temperature from high to low; S2. The hot exhaust gas from the first and second sections is sent to the waste heat boiler for waste heat power generation, and the hot exhaust gas after waste heat utilization is returned to the ring cooler; S3. The hot exhaust gas from the third section is introduced into the combustion-supporting fan for hot air ignition, or the hot exhaust gas from the third section is delivered to the sintering machine material surface by unpowered conveying for use as hot air sintering; S4. The hot exhaust gas in the fourth section is used to produce hot water, and the hot exhaust gas after waste heat utilization is returned to the ring cooler; S5. Connect the hot exhaust gas from the 5th section to the ring cooler to achieve "zero" flue gas emissions.

2. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 1 is characterized by: In step S1, five blowers are provided corresponding to the five sections into which the ring cooler is divided, and silencers and damper regulating valves are provided at the inlets of the five blower fans.

3. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 2 is characterized by: Blowers No. 3 and No. 5 are configured as variable frequency speed regulating blowers.

4. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 1 is characterized in that: In step S2, the hot exhaust gas sent to the waste heat boiler is used to generate steam, and the generated steam is sent to the steam-assisted condensing steam turbine generator set for waste heat power generation, so that the exhaust temperature of the waste heat boiler is less than 140°C, and the exhaust gas of the waste heat boiler is introduced into the cooling bellows of the ring cooler through the circulating fan, and a valve is set before the return air duct enters the bellows, and ash discharge ports are set on both sides of the valve, and the circulating fan adopts frequency conversion regulation.

5. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 4 is characterized in that: A set of switching damper doors is respectively provided at the flue gas inlet and outlet systems of the waste heat boiler to facilitate isolation at any time when the waste heat recovery system fails.

6. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 1 is characterized by: In step S3, the hot exhaust gas from the third section is introduced to the combustion-supporting blower after multi-tube dust removal to increase the combustion-supporting air temperature of the sintering machine ignition furnace to a temperature ≥ 200°C to achieve hot air ignition.

7. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 1 is characterized by: In step S3, the hot exhaust gas from the third section is sent to the material surface of the sintering trolley through the hot air duct via the ring cooling blower to achieve hot air sintering.

8. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 7 is characterized by: A manual inspection door is provided on the hot air duct, and an ash discharge funnel is provided at the dust accumulation part of the hot air duct. The outer surface of the hot air duct is insulated with thermal insulation materials, and an electric regulating valve is provided on the hot air duct.

9. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 2 is characterized by: In step S4, the hot exhaust gas of the 4th section produces hot water through the hot water exchanger, and the exhaust gas flowing out of the hot water exchanger is sent to the air inlet of the No. 4 blower and enters the ring cooler to realize the self-circulation of this section of exhaust gas.

10. The zero-emission process for comprehensive utilization of waste heat from sintering ring cooler exhaust gas according to claim 2 is characterized by: In step S4, the hot exhaust gas from the 5th section is connected to the air inlet of the No. 3 blower and enters the ring cooler to achieve "zero" flue gas emissions.

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