Acid regeneration byproduct reduction system and reduction method

Abstract

The invention discloses an acid regeneration byproduct reduction system and a reduction method. Comprising a coke oven gas reforming module, an iron oxide sand reduction module and an acid regeneration furnace module, the coke oven gas reforming module comprises a coke oven gas header pipe, a preheater and a cracker, the coke oven gas header pipe is connected with the preheater, the coke oven gas header pipe provides coke oven gas to be heated and combusted coke oven gas for the preheater, and the preheater is connected with the cracker; the cracker is used for cracking oxygen and preheated coke oven gas to obtain reducing gas; the acid regeneration furnace module comprises an acid regeneration furnace, a burner and an iron oxide sand blanking channel, the burner is arranged on the acid regeneration furnace, and the iron oxide sand blanking channel and the burner are connected with a coke oven gas header pipe; the iron oxide sand reduction module comprises a reduction section and a cooling section, the reduction section is located on the upper portion of the cooling section, the reduction section is connected with the cracker, the iron oxide sand discharging channel and the combustor, the reduction section is used for reducing iron oxide sand into iron powder in the reducing atmosphere and discharging waste gas to the combustor, and the cooling section is used for cooling the iron powder. The acid regeneration system has the advantages of simple equipment, low energy consumption, low cost, high benefit, no pollution and full recovery, the economic benefit of the acid regeneration system is greatly improved, and the acid regeneration system with the iron oxide sand reduction function has higher market competitiveness.

Description

Technical Field:

[0001] The present invention belongs to the technical field of acid regeneration systems, and particularly relates to a method for reducing by-product iron oxide sand of an acid regeneration fluidized bed into high-purity iron powder. Background Art:

[0002] Currently, many domestic steel enterprises need to use the pickling process during production. The waste acid after use will be regenerated into new acid through the acid regeneration fluidized bed process and reused to achieve the purpose of environmental protection and cost savings. However, while this acid regeneration fluidized bed process regenerates the waste acid, iron oxide in the waste acid will precipitate to form iron oxide sand, which is discharged from the lower part of the fluidized bed. The temperature of the discharged iron oxide sand is as high as about 900°C, and the heat of the discharged iron oxide sand accounts for nearly half of the heat consumption of the acid regeneration fluidized bed. Currently, this kind of iron oxide sand can generally only be used as raw materials for permanent magnets and other low-value applications, and the market capacity is limited, with low value, and even becomes a solid waste that is difficult to handle.

[0003] However, at the same time, the impurity content of this kind of iron oxide sand is very small, and the iron oxide content is as high as more than 99%. If it can be reduced into high-purity iron powder, its pure iron content can be as high as more than 99%, and it can be completely used as high-purity iron powder with high purity, and its value can be increased several times.

[0004] The acid regeneration system generally depends on steel enterprises and mostly uses coke oven gas as fuel. How to utilize the by-product iron oxide sand of the acid regeneration furnace, the heat carried by the iron oxide sand, and reform the coke oven gas nearby, mix the coke oven gas with oxygen and pyrolyze it to generate reducing gas, and reduce the iron oxide sand into high-purity iron powder with less energy consumption, so as to form a new acid regeneration system with short process, low energy consumption, high efficiency, and full recovery is a problem that needs to be solved.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of implication that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention:

[0006] The purpose of the present invention is to provide an acid regeneration by-product reduction system and a reduction method, so as to overcome the defects in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides an acid regeneration by-product reduction system, including a coke oven gas reforming module, an iron oxide sand reduction module, and an acid regeneration furnace module. The coke oven gas reforming module is respectively connected to the iron oxide sand reduction module and the acid regeneration furnace module, and the acid regeneration furnace module is connected to the iron oxide sand reduction module. The coke oven gas reforming module includes a coke oven gas main pipe, a preheater, and a cracker. The coke oven gas main pipe is connected to the preheater, and the coke oven gas main pipe provides the coke oven gas to be heated and the burning coke oven gas for the preheater. The preheater is connected to the cracker, and the cracker is used for cracking oxygen and the preheated coke oven gas to obtain reduction gas. The acid regeneration furnace module includes an acid regeneration furnace, a burner, and an iron oxide sand feeding channel. The acid regeneration furnace is provided with a burner and an iron oxide sand feeding channel, and the burner is connected to the coke oven gas main pipe. The iron oxide sand reduction module includes a reduction section and a cooling section. The reduction section is located above the cooling section. The reduction section is respectively connected to the cracker, the iron oxide sand feeding channel, and the burner. The reduction section is used for reducing iron oxide sand into iron powder in a reducing atmosphere and discharging the waste gas to the burner. The cooling section is used for cooling the iron powder.

[0008] Preferably, in the technical solution, the coke oven gas reforming module includes a coke oven gas main pipe, a preheater, a cracker, a preheating inlet gas pipeline, and a gas pipeline. The preheater is provided with an inlet, a gas outlet, and an outlet. The inlet is connected to the coke oven gas main pipe through the preheating inlet gas pipeline, and the gas outlet is connected to the coke oven gas main pipe through the gas pipeline. The preheating inlet gas pipeline and the gas pipeline are in parallel. The cracker is provided with a coke oven gas inlet, an oxygen inlet, and a reduction gas outlet. The coke oven gas inlet is connected to the outlet of the preheater through a pipeline, and the oxygen pipeline is connected to the oxygen inlet.

[0009] Preferably, in the technical solution, a main pipe valve group is arranged on the coke oven gas main pipe, and flow regulating valves are arranged on both the preheating inlet gas pipeline and the gas pipeline.

[0010] Preferably, in the technical solution, the iron oxide sand reduction module includes a reduction section, a cooling section, an iron oxide sand inlet, a reduction gas inlet, a tail gas outlet, a coolant inlet, and a coolant outlet. The reduction section is provided with an iron oxide sand inlet, a reduction gas inlet, and a tail gas outlet. The iron oxide sand inlet is connected to the iron oxide sand feeding channel, the reduction gas inlet is connected to the reduction gas outlet of the cracker, and the tail gas outlet is connected to the burner. The cooling section is provided with a coolant inlet and a coolant outlet.

[0011] Preferably, in the technical solution, the reduction gas inlet is connected to an external reduction gas pipeline, and other external reduction gas is used to replace the reduction gas generated by the cracking of the coke oven gas reforming module.

[0012] Preferably, in the technical solution, a heat preservation layer is arranged in the reduction section to keep the iron oxide sand at a sufficient temperature during the reduction process.

[0013] Preferably, in the technical solution, the connection sequence between the preheater and the cracker is reversed. The cracker is connected to the main coke oven gas pipe through the coke oven gas inlet. The reducing gas outlet of the cracker is connected to the air inlet of the preheater, and the air outlet of the preheater is connected to the reducing gas inlet of the reduction section. Coke oven gas and oxygen are mixed in the cracker, and the cracking reaction takes place in the preheater.

[0014] Preferably, in the technical solution, the acid regeneration by-product reduction system further includes a vacuum packing machine, which is connected to the outlet of the cooling section and is arranged in a protective gas atmosphere.

[0015] A method for reducing acid regeneration by-products, the steps of which are as follows: (1) Coke oven gas enters the preheater through the main coke oven gas pipe. A part of the coke oven gas is ignited as fuel to heat the preheater, and another part of the coke oven gas is heated to about 400°C as the gas to be heated, and then sent from the preheater to the cracker.

[0016] (2) The coke oven gas entering the cracker is mixed with the oxygen entering the cracker at the same time to undergo a cracking reaction, cracking the alkene gases in the coke oven gas into reducing gas mainly composed of hydrogen and carbon monoxide gases. The reaction heat generated during the cracking reaction continues to heat the reducing gas to about 900°C. The cracked reducing gas is transported from the cracker to the reduction section.

[0017] (3) The main coke oven gas pipe transports coke oven gas to the burner of the acid regeneration furnace as fuel. The coke oven gas in the burner is mixed with air for combustion. Iron oxide sand is generated during the acid regeneration process in the acid regeneration furnace. The iron oxide sand at about 900°C enters the reduction section through the iron oxide sand feeding channel.

[0018] (4) The reducing gas continuously contacts the iron oxide sand from top to bottom from bottom to top in the reduction section. Under the high temperature condition of about 900°C, the iron oxide sand is reduced to iron powder by the reducing gas. At the outlet of the reduction section, all the iron oxide sand has been reduced to high-purity iron powder. The tail gas after the reaction in the reduction section is transported to the burner to utilize all the heat enthalpy of the tail gas.

[0019] (5) The high-purity iron powder enters the cooling section and exchanges heat with the coolant. The high-purity iron powder is cooled to below 85°C and enters the subsequent processing.

[0020] (6) After the high-purity iron powder is output from the cooling section, it enters the vacuum packing machine and is vacuum-packed in a protective atmosphere.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The iron oxide sand with low original value and narrow application range is reduced to high-purity iron powder with wider application and higher value. At present, the selling price of iron oxide sand in the domestic market is about 1,200 yuan / ton, while the selling price of high-purity iron powder with iron content > 99% is as high as 5,000 - 6,000 yuan / ton. Since the temperature of the iron oxide sand discharged from the acid regeneration furnace is about 900°C, which is exactly the temperature range required for reduction, the heat required to supplement the reduction reaction is very little, and the nearby coke oven gas main pipe can be used for gas supply. About half of the calorific value and relatively high sensible heat are still contained in the tail gas after reduction, and all are sent to the burner of the acid regeneration furnace for utilization. The present invention has the advantages of simple equipment, low energy consumption, low cost, high benefit, no pollution and full recovery, greatly improving the economic benefit of the acid regeneration system, and the acid regeneration system with the function of reducing iron oxide sand has greater market competitiveness. Brief Description of the Drawings:

[0023] Figure 1 It is a schematic structural diagram of the reduction system for acid regeneration by-products of the present invention;

[0024] Figure 2 It is a flow chart of the reduction method for acid regeneration by-products of the present invention. Detailed Embodiments:

[0025] The following describes the detailed embodiments of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the detailed embodiments.

[0026] Unless otherwise clearly stated, throughout the specification and claims, the term "comprise" or its variations such as "comprises" or "including" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0027] As Figure 1 shown, an acid regeneration by-product reduction system includes a coke oven gas reforming module 100, an iron oxide sand reduction module 200, an acid regeneration furnace module 300, and a vacuum packaging machine 400. The coke oven gas reforming module 100 is respectively connected to the iron oxide sand reduction module 200 and the acid regeneration furnace module 300. The acid regeneration furnace module 300 is connected to the iron oxide sand reduction module 200; the vacuum packaging machine 400 is connected to the outlet of the cooling section, and the vacuum packaging machine 400 is arranged in an inert gas atmosphere;

[0028] The coke oven gas reforming module 100 includes a coke oven gas main pipe 1, a preheater 2, a cracker 3, a preheating inlet pipeline 4, and a gas pipeline 5; the preheater 2 is divided into a combustion zone 26 and a preheating zone 27. A gas inlet 7 and an exhaust gas outlet 25 are provided on the combustion zone 26, and an air inlet 6 and an air outlet 8 are provided on the preheating zone 27. The air inlet 6 is connected to the coke oven gas main pipe 1 through the preheating inlet pipeline 4, and the gas inlet 7 is connected to the coke oven gas main pipe 1 through the gas pipeline 5. The preheating inlet pipeline 4 and the gas pipeline 5 are in parallel. The exhaust gas generated by combustion in the preheater 2 is discharged through the exhaust gas outlet 25; a coke oven gas inlet 9, an oxygen inlet 10, and a reducing gas outlet 11 are provided on the cracker 3. The coke oven gas inlet 9 is connected to the air outlet 8 of the preheater 2 through a pipeline, and the oxygen pipeline is connected to the oxygen inlet 10; a main pipe valve group 12 is provided on the coke oven gas main pipe 1, a preheating inlet pipeline flow regulating valve 13 is provided on the preheating inlet pipeline 4, and a gas pipeline flow regulating valve 14 is provided on the gas pipeline 5;

[0029] The acid regeneration furnace module 300 includes an acid regeneration furnace 15, a burner 16, and an iron oxide sand feeding channel 17. A burner 16 and an iron oxide sand feeding channel 17 are provided on the acid regeneration furnace 15, and the burner 16 is connected to the coke oven gas main pipe 1;

[0030] The iron oxide sand reduction module 200 includes a reduction section 18, a cooling section 19, an iron oxide sand inlet 20, a reducing gas inlet 21, a tail gas outlet 22, a coolant inlet 23, and a coolant outlet 24; an iron oxide sand inlet 20, a reducing gas inlet 21, and a tail gas outlet 22 are provided on the reduction section 18. The iron oxide sand inlet 20 is connected to the iron oxide sand feeding channel 17, the reducing gas inlet 21 is connected to the reducing gas outlet 11 of the cracker 3, and the tail gas outlet 22 is connected to the burner 16; the iron oxide sand inlet 20 and the tail gas outlet 22 are located at the upper part of the reduction section 18, and the reducing gas inlet 21 is located at the lower part of the reduction section 18; the cooling section 19 is connected to the reduction section 18, and a coolant inlet 23 and a coolant outlet 24 are provided on the cooling section 19; a heat preservation layer is provided in the reduction section 18 to keep the iron oxide sand at a sufficient temperature during the reduction process;

[0031] The reducing gas inlet 21 is connected to an external reducing gas pipeline, and other external reducing gases can be used to replace the reducing gas generated by the cracking of the coke oven gas reforming module.

[0032] The connection order of the preheater 2 and the cracker 3 is reversed. The cracker 3 is connected to the coke oven gas main pipe 1 through the coke oven gas inlet 9. The reducing gas outlet 11 of the cracker 3 is connected to the air inlet 6 of the preheater 2, and the air outlet 8 of the preheater 2 is connected to the reducing gas inlet 21 of the reduction section 18; the coke oven gas and oxygen are mixed in the cracker 3, and the cracking reaction takes place in the preheater 2.

[0033] AsFigure 2 As shown in the figure, a method for reducing acid regeneration by-products, the steps of which are as follows: (1) The coke oven gas enters the preheating inlet pipeline 4 and the gas pipeline 5 respectively through the coke oven gas main pipe 1. The coke oven gas in the gas pipeline 5 enters the combustion zone 26 through the gas port 7 as fuel gas and is ignited to heat the preheating zone 27 in the preheater 2. The waste gas generated by combustion is discharged through the waste gas port 25. The coke oven gas in the preheating inlet pipeline 4 enters the preheating zone 27 through the inlet port 6 as the gas to be heated and is heated to about 400 °C, and then is sent into the cracker 3 through the outlet port 8 and the coke oven gas inlet 9;

[0034] (2) The coke oven gas entering the cracker 3 is mixed with the oxygen entering the cracker 3 simultaneously through the oxygen inlet 10 and undergoes a cracking reaction, cracking the alkene gases in the coke oven gas into reduction gases mainly composed of hydrogen and carbon monoxide gases. The reaction heat generated during the cracking reaction continues to heat the reduction gases to about 900 °C. The cracked reduction gases are transported from the reduction gas outlet 11 to the reduction section 18 through the reduction gas inlet 21; The specific reaction formulas of the coke oven gas and oxygen in the cracker 3 are as follows:

[0035] CH 4 +0.5O 2 =CO+2H 2 ;

[0036] C 2 H 4 +O 2 =2CO+2H 2 ;

[0037] C 2 H 6 +O 2 =2CO+3H 2 ;

[0038] (3) The coke oven gas main pipe 1 transports coke oven gas to the burner 16 of the acid regeneration furnace 15 as fuel gas. The coke oven gas in the burner 16 is mixed with air and burned. Iron oxide sand is generated during the acid regeneration process in the acid regeneration furnace 15. The iron oxide sand at about 900 °C enters the reduction section 18 through the iron oxide sand discharge channel 17 and the iron oxide sand inlet 20;

[0039] (4) After the reducing gas enters the reduction section 18 from the coke oven gas inlet 9 at the lower part of the reduction section 18, the reducing gas is transported from bottom to top. After the iron oxide sand enters the reduction section 18 from the iron oxide sand inlet 20 at the upper part of the reduction section 18, the iron oxide sand is transported from top to bottom. In the reduction section 18, the reducing gas comes into full contact with the iron oxide sand. Under the high temperature condition of about 900 °C, the iron oxide sand is reduced by the reducing gas into spongy iron powder. At the outlet of the reduction section 18, all the iron oxide sand has been reduced into spongy high-purity iron powder. The tail gas after the reaction in the reduction section 18 is transported to the burner 16 through the tail gas outlet 22, and all the heat enthalpy of the tail gas is utilized. The specific reaction formula of the reducing gas and the iron oxide sand in the reduction section 18 is as follows:

[0040]

[0041] (5) The high-purity iron powder enters the cooling section 19 and exchanges heat with water as the coolant. The high-purity iron powder is cooled to below 85 °C and then enters the vacuum packaging machine 400.

[0042] (6) After the high-purity iron powder is output from the cooling section 19, it enters the vacuum packaging machine 400 and is vacuum-packaged in a protective atmosphere, and the packaged finished product is output from the outlet of the vacuum packaging machine 400.

[0043] The foregoing description of the specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the present invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize the various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. An acid regeneration byproduct reduction system, characterized in that: The coke oven gas reforming module comprises a coke oven gas reforming module, an iron oxide sand reduction module, and an acid regeneration furnace module. The coke oven gas reforming module is connected to the iron oxide sand reduction module and the acid regeneration furnace module respectively, and the acid regeneration furnace module is connected to the iron oxide sand reduction module; the coke oven gas reforming module comprises a coke oven gas main pipe, a preheater, and a cracker. The coke oven gas main pipe is connected to the preheater. The coke oven gas main pipe provides the preheater with coke oven gas to be heated and the coke oven gas to be burned. The preheater is connected to the cracker. The cracker is used to combine oxygen and preheated coke oven coal. The gas is cracked to obtain reducing gas; the acid regeneration furnace module includes an acid regeneration furnace, a burner and an iron oxide sand feed channel, the acid regeneration furnace is provided with a burner and an iron oxide sand feed channel, and the burner is connected to the coke oven gas main; the iron oxide sand reduction module includes a reduction section and a cooling section, the reduction section is located at the upper part of the cooling section, the reduction section is respectively connected to the cracker, the iron oxide sand feed channel and the burner, the reduction section is used to reduce the iron oxide sand into iron powder under a reducing atmosphere, and discharge the exhaust gas to the burner, and the cooling section is used to cool the iron powder.

2. The acid regeneration byproduct reduction system according to claim 1, characterized in that: The coke oven gas reforming module includes a coke oven gas main, a preheater, a cracker, a preheating air inlet pipeline, and a gas pipeline; the preheater is provided with an air inlet, a gas outlet, and a gas outlet; the air inlet is connected to the coke oven gas main through a preheating air inlet pipeline, the gas outlet is connected to the coke oven gas main through a gas pipeline, and the preheating air inlet pipeline and the gas pipeline are connected in parallel; the cracker is provided with a coke oven gas inlet, an oxygen inlet, and a reducing gas outlet; the coke oven gas inlet is connected to the air outlet of the preheater through a pipeline, and the oxygen pipeline is connected to the oxygen inlet.

3. The acid regeneration byproduct reduction system according to claim 2, characterized in that: A main valve group is provided on the coke oven gas main pipe, and flow regulating valves are provided on the preheating air inlet pipeline and the gas pipeline.

4. The acid regeneration byproduct reduction system according to claim 2, characterized in that: The iron oxide sand reduction module includes a reduction section, a cooling section, an iron oxide sand inlet, a reduction gas inlet, an exhaust gas outlet, a coolant inlet, and a coolant outlet; The reduction section is provided with an iron oxide sand inlet, a reducing gas inlet and a tail gas outlet. The iron oxide sand inlet is connected to the iron oxide sand feed channel, the reducing gas inlet is connected to the reducing gas outlet of the cracker, and the tail gas outlet is connected to the burner; the cooling section is provided with a coolant inlet and a coolant outlet.

5. The acid regeneration byproduct reduction system according to claim 4, characterized in that: The reducing gas inlet is connected to an external reducing gas pipeline.

6. The acid regeneration byproduct reduction system according to claim 4, characterized in that: A heat-insulating layer is provided in the reduction section.

7. The acid regeneration byproduct reduction system according to claim 4, characterized in that: The connection sequence of the preheater and the cracker is swapped, the cracker is connected to the coke oven gas main through the coke oven gas inlet, the reducing gas outlet of the cracker is connected to the air inlet of the preheater, and the air outlet of the preheater is connected to the reducing gas inlet of the reduction section; the coke oven gas and oxygen are mixed in the cracker, and the cracking reaction is carried out in the preheater.

8. The acid regeneration byproduct reduction system according to claim 1, characterized in that: The acid regeneration byproduct reduction system also includes a vacuum packaging machine, which is connected to the outlet of the cooling section and is arranged in a protective gas atmosphere.

9. A reduction method of the acid regeneration byproduct reduction system according to any one of claims 1 to 8, comprising the following steps: (1) coke oven gas enters a preheater through a coke oven gas main, a portion of the coke oven gas is ignited as fuel gas to heat the preheater, and another portion of the coke oven gas is heated to about 400° C. as a gas to be heated, and then is sent from the preheater to a cracker; (2) The coke oven gas entering the cracker is mixed with the oxygen entering the cracker at the same time to undergo a cracking reaction, cracking the alkane and olefin gases in the coke oven gas into a reducing gas mainly composed of hydrogen and carbon monoxide. The reaction heat generated during the cracking reaction further heats the reducing gas to about 900° C. The cracked reducing gas is transported from the cracker to the reduction section; (3) The coke oven gas main pipe delivers coke oven gas as fuel gas to the burner of the acid regeneration furnace. The coke oven gas is mixed with air in the burner for combustion. Iron oxide sand is produced in the acid regeneration furnace during the acid regeneration process. The iron oxide sand at about 900°C enters the reduction section through the iron oxide sand feed channel; (4) The reducing gas continuously contacts the iron oxide sand from top to bottom in the reduction section. Under the high temperature condition of about 900°C, the iron oxide sand is reduced to iron powder by the reducing gas. At the outlet of the reduction section, the iron oxide sand has been completely reduced to high-purity iron powder. The tail gas after the reaction in the reduction section is transported to the burner to utilize all the heat enthalpy of the tail gas. (5) The high-purity iron powder enters the cooling section and exchanges heat with the coolant. The high-purity iron powder is cooled to below 85°C and enters the post-processing stage; (6) After being discharged from the cooling section, the high-purity iron powder enters the vacuum packaging machine and is vacuum packaged in a protective atmosphere.

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