Chain loop pellet energy conservation and emission reduction system

Abstract

The invention discloses an energy conservation and emission reduction system for chain-back pellets, and belongs to the technical field of chain-back pellet production. Comprising a chain grate, a rotary kiln and a circular cooler which are sequentially connected, two ends of a hot air pipeline c are respectively connected with a third-cooling-section hot air outlet and a drum drying-section hot air inlet, two ends of a hot air pipeline a are respectively connected with a first-cooling-section hot air outlet and the hot air pipeline c, and two ends of a hot air pipeline b are respectively connected with a second-cooling-section hot air outlet and a preheating first-section hot air inlet. A hot air outlet of the second preheating section is connected with a hot air inlet of the drying section through a hot air pipeline d; an upper cover waste gas outlet of the blow-drying section is connected with a cooling inlet of the first cooling section, air box outlets of the pumping section and the first preheating section are connected with a waste gas treatment unit which is connected with an exhaust unit, and a hot air outlet of the fourth cooling section is connected with a cooling inlet of the second cooling section. The method has the beneficial effects that the resource recycling rate is remarkably increased; the equipment investment and the operation cost are effectively reduced; optimizing and upgrading the operation efficiency of the equipment; the environment-friendly treatment effect is obvious; the energy consumption is lower.

Description

TECHNICAL FIELD

[0001] The present application relates to a chain back ring pellet energy-saving and emission-reducing system, belonging to the technical field of chain back ring pellet production. BACKGROUND

[0002] The chain grate-rotary kiln-ring cooler (referred to as "chain back ring") pellet production process, as a mature mainstream technology in the field of iron ore pellet production, has been widely used in domestic and foreign large and medium-sized steel enterprises due to its high production efficiency, stable pellet quality and other advantages, and has become a key link between iron ore powder processing and blast furnace smelting. However, with the increasingly stringent national environmental protection regulations and the continuous rise of energy prices, the inherent problems of this process, such as high energy consumption per ton of ore production and large amount of flue gas discharge, have become increasingly prominent, not only significantly increasing production costs, but also making enterprises face heavy environmental compliance pressure, restricting their green and low-carbon development.

[0003] The defects and deficiencies of the existing chain back ring pellet production process are specifically embodied in the following aspects: (1) Large amount of flue gas discharge per unit of pellet production, with high concentrations of dust, SO2 and other pollutants, resulting in the need for larger treatment scale of environmental protection facilities, not only high initial investment, but also high energy consumption of fans, reagent consumption and other costs during operation, and prone to fluctuations in emission indicators, poor environmental friendliness; (2) There is a significant imbalance in the hot air system, with a serious surplus of flue gas at the kiln tail process, requiring additional configuration of a diffuser, while the preheating I section is in a dilemma of insufficient flue gas and low temperature, which cannot meet the preheating demand of iron ore powder, and additional energy is consumed for heating; (3) High fuel consumption per unit of pellet production, affected by low hot air utilization efficiency and high heat loss, fuel costs account for a high proportion of pellet production costs; (4) High energy consumption in the flue gas treatment process itself, such as power consumption of desulfurization and denitrification systems, and regeneration energy consumption of adsorbents, further adding to production costs, making it difficult for enterprises to form a price advantage in the background of increasing competition in the steel industry.

[0004] The patent with publication number CN110721568A and the patent name of a pellet roasting flue gas denitrification and desulfurization device and method based on a chain grate-rotary kiln adopts a series structure of "rotary kiln + built-in denitrification agent injection device of chain grate", the second preheating section of the chain grate is divided into at least 3 denitrification sections, and the denitrification agent injection device is arranged equidistantly at the junction of the flue hood area and the reaction area of each section. The technical solution of this patent has the following defects: the hot air system is unbalanced, the preheating section has insufficient flue gas temperature and quantity, additional heating is required, fuel consumption is high, heat loss accounts for a high proportion, and single-ton pellet fuel consumption is high; high energy consumption and reagent consumption in flue gas treatment, high production cost. SUMMARY

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a chain-recycled energy-saving and emission-reduction system for reducing ton-ballistic flue gas emissions, lowering energy consumption, improving fuel utilization, and reducing costs.

[0006] The technical solution of the present invention is: a chain grate energy-saving and emission-reduction system, comprising a chain grate machine, a rotary kiln and an annular cooler connected in sequence. The chain grate machine passes through a drying section, a desiccation section, a preheating section 1 and a preheating section 2 in sequence. The preheating section 2 is connected to the rotary kiln. The main burner is provided at the kiln head hood of the rotary kiln. The feed hopper of the annular cooler is connected to one side of the kiln head hood of the rotary kiln. The annular cooler also includes a first cooling section, a second cooling section, a third cooling section and a fourth cooling section. Hot air duct c is connected to the hot air outlet of the third cooling section and the hot air inlet of the drying section at both ends, hot air duct a is connected to the hot air outlet of the first cooling section and hot air duct c at both ends, hot air duct b is connected to the hot air outlet of the second cooling section and the hot air inlet of the first preheating section at both ends, and the hot air outlet of the second preheating section and the hot air inlet of the drying section are connected by hot air duct d. The exhaust outlet of the blower section is connected to the cooling inlet of the first cooling section. The air box outlet of the desiccation section and the preheating section is connected to the exhaust gas treatment unit. The exhaust gas treatment unit is connected to the exhaust unit. The hot air outlet of the fourth cooling section is connected to the cooling inlet of the second cooling section.

[0007] The hot air duct a and the hot air duct b are connected by a pipe a, and a control valve a is installed on the pipe a.

[0008] The hot air duct a is equipped with a control valve b that controls the supply of hot air to the hot air duct c.

[0009] A blower is installed on the hot air duct c at the hot air inlet of the blower section.

[0010] The hot air duct d is equipped with a multi-tube dust collector, a first SCR denitrification device, and a regenerative air fan.

[0011] A kiln tail hood is provided between the rotary kiln and the preheating section, and a second SCR de-pinning device is provided at the kiln tail hood.

[0012] The hot air duct a is connected to the kiln head hood via pipe b.

[0013] The exhaust gas treatment unit includes an electrostatic precipitator, a main exhaust fan, and a desulfurization device, and the exhaust unit is a chimney.

[0014] A fan a is provided at the cooling inlet of the first cooling section, which can introduce exhaust gas from the drying section and outside air into the first cooling section. A fan b is provided at the cooling inlet of the second cooling section, which can introduce hot air from the fourth cooling section and outside air into the second cooling section. A fan c is provided at the cooling inlet of the third cooling section, which can introduce outside air into the third cooling section. A fan d is provided at the cooling inlet of the fourth cooling section, which can introduce outside air into the fourth cooling section.

[0015] The beneficial effects of the present application include: 1. Resource recycling rate is significantly improved. The flue gas of the upper cover of the blast drying section is reused in the first cooling section of the ring cooler, and the waste gas of the fourth cooling section of the ring cooler is reused in the second cooling section, which not only avoids the waste of heat energy caused by direct flue gas discharge, but also fully utilizes the waste heat as a cooling medium to realize energy cascade utilization; at the same time, the preheating section of the chain grate machine and the drying section are heated by connecting with the heat recovery air pipe of the ring cooler, replacing the traditional combustion heating mode, greatly reducing fuel consumption and reducing energy costs.

[0016] 2. The equipment investment and operation cost is effectively reduced. The drying section upper cover flue gas dust collector and the supporting flue gas treatment facilities are cancelled, reducing the initial investment of equipment purchase, installation and maintenance; at the same time, there is no need for additional investment in the operation cost of combustion heating equipment, and the flue gas recycling reduces the subsequent treatment load, further reducing the long-term operation energy consumption and cost of the system.

[0017] 3. The equipment operation efficiency is optimized and upgraded. Through the improvement of waste heat recovery and heating mode, the design specification of the chain grate machine can be effectively reduced, the equipment utilization coefficient is improved under the premise of ensuring the production capacity, the equipment structure is simplified, the land occupation area and operation loss are reduced, and the overall operation stability of the system is improved.

[0018] 4. The environmental protection treatment effect is remarkable and the energy consumption is lower. The SNCR denitrification device is set at the high-temperature flue gas of the rotary kiln tail, the SCR denitrification device is configured combined with the preheating second section heat recovery flue gas temperature, the pre-denitrification design is adopted, which avoids the disadvantages of large fuel consumption and large flue gas treatment capacity in the traditional post-denitrification mode, ensures the denitrification efficiency to meet the standard, further reduces the environmental protection treatment energy consumption, realizes the coordinated development of energy saving and emission reduction and environmental protection standard. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The structure diagram of the present application.

[0020] The reference signs in the drawings are as follows: 1. Chain grate machine; 2, rotary kiln; 3, ring cooler; 4, drying section; 5, drying section; 6, preheating section 1; 7, preheating section 2; 8, kiln head cover; 9, main burner; 10, first cooling section; 11, second cooling section; 12, third cooling section; 13, fourth cooling section; 14, hot air pipe a; 15, hot air pipe b; 16, hot air pipe c; 17, hot air pipe d; 18, pipeline a; 19, control valve a; 20, control valve b; 21, drying fan; 22, multi-tube dust collector; 23, first SCR denitrification device; 24, heat recovery fan; 25, kiln tail cover; 26, second SCR denitrification device; 27, pipeline b; 28, electrostatic precipitator; 29, main exhaust fan; 30, desulfurization device; 31, chimney; 32, fan a; 33, fan b; 34, fan c; 35, fan d. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the present application will be described in detail below with reference to the drawings and detailed embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0022] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0023] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from the description, and those skilled in the art can make similar generalizations without departing from the essence of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0024] Secondly, the present application is described in detail in combination with the schematic diagram, in the detailed description of the embodiments of the present application, in order to facilitate the description, the cross-sectional view of the device structure will be partially enlarged without the general proportion, and the schematic diagram is only an example, which should not limit the scope of protection of the present application here. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in actual manufacture.

[0025] The specific embodiments of the present application will be described in detail below with reference to the drawings Figure 1 Further description of the present application: The system comprises a chain grate machine 1, a rotary kiln 2 and a ring cooler 3 connected in sequence, the chain grate machine 1 sequentially passes through a drum drying section 4, a drying section 5, a preheating section 1 6 and a preheating section 2 7, the preheating section 2 7 is connected with the rotary kiln 2, a main burner 9 is arranged at a kiln head cover 8 of the rotary kiln 2, one side of the kiln head cover 8 of the rotary kiln 2 is connected with a feeding hopper of the ring cooler 3, the ring cooler 3 further comprises a cooling section 1 0, a cooling section 2 1 1, a cooling section 3 1 2 and a cooling section 4 1 3, two ends of a hot air pipeline c 1 6 are respectively connected with a hot air outlet of the cooling section 3 1 2 and a hot air inlet of the drum drying section 4, two ends of a hot air pipeline a 1 4 are respectively connected with a hot air outlet of the cooling section 1 0 and the hot air pipeline c 1 6, two ends of a hot air pipeline b 1 5 are respectively connected with a hot air outlet of the cooling section 2 1 1 and a hot air inlet of the preheating section 1 6, a hot air outlet of the preheating section 2 7 is connected with a hot air inlet of the drying section 5 through a hot air pipeline d 1 7, a waste gas outlet of the drum drying section 4 is connected with a cooling inlet of the cooling section 1 0, air box outlets of the drying section 5 and the preheating section 1 6 are connected with a waste gas treatment unit, the waste gas treatment unit is connected with an external exhaust unit, a hot air outlet of the cooling section 4 1 3 is connected with a cooling inlet of the cooling section 2 1 1. The waste gas treatment unit comprises an electric dust collector 2 8, a main exhaust fan 2 9 and a desulfurization device 3 0, the external exhaust unit is a chimney 3 1. A multi-pipe dust collector 2 2, a first SCR denitration device 2 3 and a heat recovery fan 2 4 are arranged on the hot air pipeline d 1 7. A kiln tail cover 2 5 is arranged between the rotary kiln 2 and the preheating section 2 7, a second SCR denitration device 2 6 is arranged at the kiln tail cover 2 5. A drum drying fan 2 1 is arranged on the hot air pipeline c 1 6 at the hot air inlet of the drum drying section 4.

[0026] Green balls enter the chain grate machine 1, sequentially pass through the drum drying section 4, the drying section 5, the preheating section 1 6 and the preheating section 2 7, hot air of these process sections respectively comes from the cooling section 3 1 2 of the ring cooler 3, the air box of the preheating section 2 7 of the chain grate machine 1, the cooling section 2 1 1 of the ring cooler 3 and the rotary kiln 2. The waste gas of the drum drying section 4 is introduced to the cooling fan inlet of the cooling section 1 0 of the ring cooler 3 by the fan, as a cooling medium; the air box waste gas (after nitrogen oxide purification) of the drying section 5 and the preheating section 1 6 is externally exhausted through the electric dust collector 2 8, the main exhaust fan 2 9, the desulfurization device 3 0 and the chimney 3 1; the high-temperature flue gas from the rotary kiln 2 contains a large amount of nitrogen oxides, the second SCR denitration device 2 6 is arranged at the kiln tail cover 2 5, after removing a certain proportion of nitrogen oxides, the flue gas after heat exchange with the preheating section 2 ball sequentially passes through the multi-pipe dust collector 2 2, the first SCR denitration device 2 3 and the heat recovery fan 2 4, and enters the upper cover of the drying section 5.

[0027] A pipeline a 1 8 is connected between the hot air pipeline a 1 4 and the hot air pipeline b 1 5, and a control valve a 1 9 is arranged on the pipeline a 1 8. A control valve b 2 0 for controlling the supply of hot air to the hot air pipeline c 1 6 is arranged on the hot air pipeline a 1 4. A pipeline b 2 7 is connected between the hot air pipeline a 1 4 and the kiln head cover 8.

[0028] A fan a32 is provided at the cooling inlet of the first cooling section 10, which can introduce exhaust gas from the drying section 4 and external air into the first cooling section 10. A fan b33 is provided at the cooling inlet of the second cooling section 11, which can introduce hot air from the fourth cooling section 13 and external air into the second cooling section 11. A fan c34 is provided at the cooling inlet of the third cooling section 12, which can introduce external air into the third cooling section 12. A fan d35 is provided at the cooling inlet of the fourth cooling section 13, which can introduce external air into the fourth cooling section 13.

[0029] The rotary kiln 2 kiln head hood 8 is equipped with a main burner 9. The high-temperature flue gas from the main burner 9 is mixed with the feed hopper from the annular cooler 3 and the hot air from the first cooling section 10 before entering the rotary kiln 2 as the calcining medium. The hot air pipe a14 of the first cooling section 10 and the hot air pipe b15 of the second cooling section 11 are connected by a pipe a18. A control valve a19 is installed on the pipe a18. By adding a certain proportion of the hot air from the first cooling section 10, the second cooling section 11 can meet the production purpose.

[0030] The inlet of fan a32 of the first cooling section 10 of the annular cooler 3 receives flue gas from the upper cover of the drying section 4 of the chain grate 1, and the insufficient part is drawn in air through a three-way valve; the inlet of fan b33 of the second cooling section 11 of the annular cooler 3 receives exhaust gas from the fourth cooling section 13 of the annular cooler 3, and the insufficient part is drawn in air through a three-way valve; the fan c34 of the third cooling section 12 and the fan d35 of the fourth cooling section 13 of the annular cooler 3 directly draw in air as a cooling medium; in order to ensure the hot air temperature of the third cooling section, the hot air pipe a14 of the first cooling section 10 and the hot air pipe c16 of the third cooling section 12 are connected and a control valve b20 is installed, and the third cooling section 12 meets the production purpose by adding a certain proportion of hot air from the first cooling section 10.

[0031] The applicant reiterates the following improvements of the present invention: (1) The flue gas on the upper cover of the blower drying section is no longer discharged and is reused as a cooling medium in the first cooling section 10 of the ring cooler 3; (2) Eliminate the dust collector and flue gas treatment facilities on the drying section to reduce construction investment and operating costs; (3) The preheating section 6 of the chain grate machine 1 does not need to be heated by combustion, and is heated by connecting the reheat air duct of the cooling section 10 of the ring cooler 3; (4) It can effectively reduce the specifications of the chain grate machine 1 and improve the utilization rate; (5) The exhaust gas of the fourth cooling section 13 of the annular cooler 3 is not discharged externally, but is reused as a cooling medium in the second cooling section 11 of the annular cooler 3; (6) The dry section 4 of the chain grate machine 1 does not need to be heated by combustion, and is heated by connecting the reheat air duct of the second cooling section 11 of the ring cooler 3; (7) Using the high-temperature flue gas at the tail of rotary kiln 2, a second SNCR denitrification device 26 is set up, and using the temperature of the reheated flue gas in the preheating stage 7, a first SCR denitrification device 23 is set up. The system denitrification is pre-positioned to avoid the disadvantages of fuel consumption and large amount of flue gas to be treated in the post-denitrification.

[0032] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A chain-linked global energy-saving and emission-reduction system, characterized in that, The system includes a chain grate machine (1), a rotary kiln (2), and an annular cooler (3) connected in sequence. The chain grate machine (1) passes through a drying section (4), a drying section (5), a preheating section (6), and a preheating section (7) in sequence. The preheating section (7) is connected to the rotary kiln (2). The main burner (9) is provided at the kiln head hood (8) of the rotary kiln (2). The feed hopper of the annular cooler (3) is connected to one side of the kiln head hood (8) of the rotary kiln (2). The annular cooler (3) also includes a first cooling section (10), a second cooling section (11), a third cooling section (12), and a fourth cooling section (13). Hot air duct c(16) is connected to the hot air outlet of the third cooling section (12) and the hot air inlet of the drying section (4) at both ends respectively. Hot air duct a(14) is connected to the hot air outlet of the first cooling section (10) and hot air duct c(16) at both ends respectively. Hot air duct b(15) is connected to the hot air outlet of the second cooling section (11) and the hot air inlet of the first preheating section (6) at both ends respectively. The hot air outlet of the second preheating section (7) and the hot air inlet of the drying section (5) are connected by hot air duct d(17). The exhaust outlet of the blower section (4) is connected to the cooling inlet of the first cooling section (10), the exhaust outlet of the blower section (5) and the preheating section (6) is connected to the exhaust gas treatment unit, the exhaust gas treatment unit is connected to the exhaust unit, and the hot air outlet of the fourth cooling section (13) is connected to the cooling inlet of the second cooling section (11).

2. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, A pipe a (18) is connected between the hot air pipe a (14) and the hot air pipe b (15), and a control valve a (19) is provided on the pipe a (18).

3. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, The hot air duct a (14) is equipped with a control valve b (20) to control the supply of hot air to the hot air duct c (16).

4. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, A blower (21) is installed on the hot air duct c (16) at the hot air inlet of the blower section (4).

5. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, The hot air duct d (17) is equipped with a multi-tube dust collector (22), a first SCR denitrification device (23), and a regenerating fan (24).

6. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, A kiln tail cover (25) is provided between the rotary kiln (2) and the preheating section (7), and a second SCR de-pinning device (26) is provided at the kiln tail cover (25).

7. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, The hot air duct a (14) is connected to the kiln head hood (8) by the connecting pipe b (27).

8. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, The exhaust gas treatment unit includes an electrostatic precipitator (28), a main exhaust fan (29), and a desulfurization device (30), and the exhaust unit is a chimney (31).

9. The energy-saving and emission-reduction system for the chain-linked global cluster according to claim 1, characterized in that, A fan a (32) is provided at the cooling inlet of the first cooling section (10). The fan a (32) can introduce exhaust gas from the drying section (4) and external air into the first cooling section (10). A fan b (33) is provided at the cooling inlet of the second cooling section (11). The fan b (33) can introduce hot air from the fourth cooling section (13) and external air into the second cooling section (11). A fan c (34) is provided at the cooling inlet of the third cooling section (12). The fan c (34) can introduce external air into the third cooling section (12). A fan d (35) is provided at the cooling inlet of the fourth cooling section (13). The fan d (35) can introduce external air into the fourth cooling section (13).

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