Iron-coke coupled fine coal pyrolysis process and system

Abstract

The present invention provides a ferrocoke coupled fine coal pyrolysis process and system, which realizes the coupling of coal pyrolysis technology and shaped ferrocoke coal carbonization technology, produces ferrocoke products, optimizes materials before entering the furnace, and enhances the blockiness and strength of the materials; utilizes the coal gas generated during the carbonization and pyrolysis of the ferrocoke as the main fuel of the carbonization furnace and performs protective reduction on the iron ore powder in the ferrocoke; utilizes the waste heat of the materials and the gas to achieve graded and uniform pyrolysis of the raw coal, and improves the pyrolysis coal gas yield and tar recovery rate; integrates metallurgical reduction and coal classification and quality-based utilization, and improves energy utilization; solves the problem of large-scale energy consumption during single coking and iron oxide reduction, saves a large amount of energy, and reduces the overall production cost.

Description

Technical Field

[0001] The invention relates to the technical field of coal chemical industry and iron ore powder reduction, and in particular to an iron-coke coupled fine coal pyrolysis process and system. Background Art

[0002] Coal rapid pyrolysis refers to the process of placing coal powder in a rapid pyrolysis device at a certain temperature, and undergoing high-temperature pyrolysis in a very short period of time, so that the organic matter in the coal powder becomes gas or coal tar, and the fixed carbon becomes semi-coke. Coal rapid pyrolysis will produce a large amount of powdered semi-coke, which is difficult to burn and use directly, and is difficult to shape. It is necessary to add a binder to make it into molded coke before reuse.

[0003] CN101984027A The invention discloses a coke powder type coke binder and a method for preparing molded coke based on the binder. The coke powder after pyrolysis is crushed into coke powder with a particle size of less than 3 mm, 1 part of the coke powder type coke binder is added to every 9 parts of the coke powder, stirred for 10 to 15 minutes, discharged, left at room temperature for 15 to 20 minutes, put into a molding machine for pressure molding, pressed into a cylindrical shape, left at room temperature for 2 to 8 hours, and then dried at 120°C.

[0004] CN103436312A The invention discloses a composite industrial gasification coke binder and a method for preparing the coke. The powdered coke after pyrolysis is crushed, and the powdered coke and the binder are placed in a kneading pot and stirred to mix evenly. The mixture is sent to a roller press, and is pressurized and formed at room temperature. The coke is obtained after drying and cooling.

[0005] CN105950242A The present invention provides a composite binder for forming coke, a coke containing the composite binder and a preparation method thereof. The coke formed by using the composite binder and semi-coke produced by rapid pyrolysis of lignite has good strength and is convenient for storage, transportation and use. The method for preparing the coke provided by the present invention is also very simple and easy to promote and apply industrially.

[0006] In the above technical scheme, the adhesive is mixed with the semi-coke after pyrolysis to form the semi-coke, and the reinforcing effect on the coke is limited. Therefore, the raw materials used to form the semi-coke require high-grade iron ore resources, and low-grade oxide ores cannot be fully utilized.

[0007] In addition, the prior art uses the flue gas at the blast furnace outlet as the heat source for pyrolysis. The pyrolysis gas generated during the pyrolysis process is diluted by the flue gas, and the generated mixed gas has a low calorific value, a low content of effective components, and a low utilization value. Summary of the invention

[0008] The present invention provides an iron coke coupled fine coal pyrolysis process, which realizes the coupling of coal pyrolysis technology and iron coke coal carbonization technology to produce iron coke products.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] An iron-coke coupled fine coal pyrolysis process comprises the following steps:

[0011] a. Mix and crush 35%-45% of raw iron powder, 54%-64% of coking coal and 1%-3% of binder, and then send them to high-pressure molding equipment for molding;

[0012] b. The formed iron coking coal is dried by a drying device;

[0013] c. After drying, the iron coking coal enters the carbonizing furnace for carbonization;

[0014] d. The carbonized high-temperature iron coke enters the heat carrier combined pyrolysis device as the first raw material; the fine coal and small-particle coal are processed by the fine coal bin and the small-particle coal pyrolysis filtration device respectively, and then enter the heat carrier combined pyrolysis device as the second and third raw materials;

[0015] e. The material after pyrolysis by the heat carrier combined pyrolysis device enters the cooling device for cooling;

[0016] f. The cooled products enter the magnetic separation equipment for magnetic separation, and the finished iron coke products and semi-coke products are output;

[0017] g. The semi-coke product enters the screening equipment and outputs the semi-coke powder and semi-coke particles.

[0018] Preferably, in step b, the heat source of the drying device is composed of high-temperature exhaust gas generated by the carbonization furnace and hot exhaust gas generated by the cooling device, and the exhaust gas generated by the drying device enters the dust collector for dust removal.

[0019] Preferably, the dust produced by the dust collector is sent to the raw material port of the high-pressure forming equipment for recycling, and part of the waste gas produced by the dust collector is discharged into the atmosphere, and the other part enters the cooling device to participate in cooling the hot material and pressure-equalizing sealing.

[0020] Preferably, in step d, the raw coal gas generated by pyrolysis of the heat carrier combined with the heating device is subjected to dust removal, filtration and cooling by the small-particle coal pyrolysis filtration device, and then purified by the condensation recovery device to form circulating coal gas, which is then sent back to the carbonization furnace for use.

[0021] Preferably, in step a, the iron powder is iron ore powder or iron concentrate powder.

[0022] The present invention also provides an iron-coke coupled fine coal pyrolysis system, comprising:

[0023] High pressure forming equipment, drying equipment, carbonization furnace, heat carrier combined pyrolysis equipment, cooling equipment, magnetic separation equipment and screening equipment;

[0024] The high pressure forming equipment is provided with a first feed inlet, a second feed inlet and a third feed inlet, wherein the first feed inlet is connected to the raw material outlet of the iron powder, the second feed inlet is connected to the raw material outlet of the coking coal, and the third feed inlet is used to add a binder and fully mix it with the iron powder and the coking coal in proportion;

[0025] The feed inlet of the drying device is connected to the discharge port of the high-pressure forming equipment, the first heat source inlet of the drying device is connected to the high-temperature exhaust gas outlet of the carbonization furnace, the second heat source inlet of the drying device is connected to the hot exhaust gas outlet of the cooling device, and the discharge port of the drying device is connected to the feed inlet of the carbonization furnace;

[0026] The first feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the carbonization furnace, the second feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the final coal bin, the third feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the small-particle coal pyrolysis device, the discharge port of the heat carrier combined pyrolysis device is connected to the feed port of the cooling device, and the air outlet is connected to the air inlet of the small-particle coal pyrolysis device;

[0027] The discharge port of the cooling device is connected to the feed port of the magnetic separation device. The discharge port of the magnetic separation device outputs iron coke in one way and is connected to the feed port of the screening device in the other way. The discharge port of the screening device outputs semi-coke powder and semi-coke particles respectively.

[0028] Furthermore, it also includes a condensation recovery device, the air inlet of which is connected to the raw coal gas outlet of the small-particle coal pyrolysis and filtration device, and the air outlet of the condensation recovery device is connected to the gas inlet of the carbonization furnace through a gas blower.

[0029] Furthermore, it also includes a dust collector, the inlet of which is connected to the air outlet of the drying device, the dust ash outlet of the dust collector is connected to the feed inlet of the high-pressure forming equipment, the first air outlet of the dust collector is connected to the atmosphere to discharge part of the exhaust gas into the atmosphere, and the second air outlet of the dust collector is connected to the air inlet of the cooling device via the exhaust gas circulation fan.

[0030] It can be seen from the above technical scheme that the present invention adopts the method of forming iron coke by high pressure molding the raw materials (iron powder, coking coal, dust removal ash) with the aid of a binder, heating and carbonizing in a carbonization furnace, and using the circulating coal gas generated by pyrolysis to heat the carbonization furnace. Compared with the prior art, the present invention has the following technical effects:

[0031] 1. Iron powder is used as a thinning agent and added to gas fertilizer coal. High-density iron coke is formed through high-pressure molding equipment. The carbonization furnace quickly heats the iron coke to the carbonization temperature in an undisturbed environment, so that the colloid formed by the coking coal evenly embedded in the iron coke at a certain temperature is fully filled between the particles. The binder ensures that the density and shape of the iron coke remain unchanged under the high-temperature carbonization environment, which is conducive to the filling of the colloid between the particles to form a dense carbon skeleton and generate iron-containing coke with a certain strength and size, overcoming the weakness of poor coke strength and small size when gas fertilizer coal is coked alone;

[0032] 2. Utilize the hydrogen-rich gas, carbon monoxide gas and high-temperature carbon particles generated during the carbonization process of molded iron coking coal to carry out gas-solid and solid-solid reduction reactions on iron concentrate or iron ore powder during the high-temperature carbonization process, that is, molded coke is generated as the coke and ore feed for the blast furnace, and the iron oxide is pre-reduced, so that the grade of the iron material entering the furnace is increased and the volume of the feed is reduced;

[0033] 3. Use the sensible heat of hot iron coke to achieve full-particle pyrolysis of coal. Send the fine coal to the heat carrier combined pyrolysis device to cool the hot iron coke in a reducing atmosphere and dry distill itself during the cooling process. Send the small-particle coal to the small-particle coal pyrolysis filtration device to cool and filter the high-temperature raw coal gas and heat itself at the same time.

[0034] 4. Use the coal gas produced by iron coke carbonization and the pyrolysis coal gas produced by the pyrolysis device as the main fuel of the carbonization furnace to achieve efficient use of the rich coal gas.

[0035] The present invention optimizes the material before entering the furnace, and enhances the size and strength of the material; utilizes the coal gas generated during the carbonization and pyrolysis of iron coke as the main fuel of the carbonization furnace and performs protective reduction on the iron ore powder in the iron coke; utilizes the waste heat of the material and the gas to achieve graded and uniform pyrolysis of the raw coal, and improves the pyrolysis coal gas yield and tar recovery rate; integrates metallurgical reduction and coal classification and quality-based utilization to improve energy utilization; solves the problem of large-scale energy consumption during single coking and iron oxide reduction, saves a large amount of energy, and reduces the overall production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a process flow chart of the iron-coke coupled fine coal pyrolysis process of the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of the iron coke coupled fine coal pyrolysis system of the present invention.

[0038] In the figure:

[0039] 100. High-pressure forming equipment, 110. Iron ore powder, dust removal ash, 120. Coking coal, 130. Binder;

[0040] 200, drying device, 201, iron coking coal after drying, 202, waste gas;

[0041] 300, carbonization furnace, 301, high temperature iron coke, 302, high temperature exhaust gas;

[0042] 400, heat carrier combined pyrolysis device, 410, fine coal, 420, small coal particles, 430, fine coal bin, 440, small coal particle pyrolysis filtration device, 401, hot iron coke, hot semi-coke fines, hot semi-coke particle mixture, 402, raw coal gas pipeline, 441, raw coal gas, 442, pre-pyrolysis small coal particles;

[0043] 500, cooling device, 501, iron coke, semi-coke mixture, 502, hot exhaust gas;

[0044] 600, magnetic separation equipment, 610, iron coke finished products, 602, semi-coke powder, semi-coke pellet mixture

[0045] 700, screening device, 710, semi-coke end product, 720, semi-coke pellet finished product;

[0046] 800, condensate recovery device, 810, gas blower, 801, gas, 811, circulating gas;

[0047] 900, dust collector, 910, exhaust gas circulation fan, 901 exhaust gas, 902, dust removal ash, 903, excess exhaust gas, 911, circulating exhaust gas. DETAILED DESCRIPTION

[0048] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0049] like Figure 2 As shown, the metallurgical reduction coupled coking and coking coal pyrolysis system of the present invention includes: high-pressure molding equipment 100, a drying device 200, a carbonization furnace 300, a heat carrier combined pyrolysis device 400, a cooling device 500, a magnetic separation device 600, a screening device 700, a condensation recovery device 800, and a dust collector 900.

[0050] The high pressure forming equipment 100 is provided with three feeding ports, which are respectively connected to the outlets of the iron ore powder 110 , the coking coal 120 , and the binder 130 . One of the inlets of the high pressure forming equipment is connected to the dust removal ash outlet of the dust collector 900 .

[0051] The first inlet of the drying device 200 is connected to the discharge port of the high-pressure molding equipment 100, the second inlet is connected to the high-temperature exhaust gas outlet of the carbonization furnace 300, and the third inlet is connected to the hot exhaust gas outlet of the cooling device 500; one outlet of the drying device 200 enters the feed port of the carbonization furnace 300, and the other outlet is connected to the inlet of the dust collector 900.

[0052] The inlet of the heat carrier combined pyrolysis device 400 is connected to the discharge port of the carbonization furnace 300 in one way, to the discharge port of the final coal bin 430 in another way, and to the outlet of the small-particle coal pyrolysis device 440 in the third way; the discharge port is connected to the feed port of the cooling device 500, and the air outlet is connected to the air inlet of the small-particle coal pyrolysis device 440.

[0053] The outlet of the magnetic separation device 600 outputs iron coke products 610 in one channel and is connected to the inlet of the screening device 700 in the other channel; the outlet of the screening device 700 outputs two products, semi-coke powder 710 and semi-coke particles 720 .

[0054] The gas inlet of the condensation recovery device 800 is connected to the raw gas outlet of the small-particle coal pyrolysis and filtering device 440 , and the outlet of the condensation recovery device 800 is connected to the gas inlet of the carbonization furnace 300 through the gas blower 810 .

[0055] The dust ash discharge port produced by the dust collector 900 is connected to the raw material port 210 of the high-pressure forming equipment; one outlet of the dust collector 900 is connected to the atmosphere to discharge part of the exhaust gas into the atmosphere, and the other outlet is connected to the air inlet of the cooling device 500 through the exhaust gas circulation fan 910.

[0056] The following is combined with Figure 1 The process of the present invention is described:

[0057] An iron-coke coupled fine coal pyrolysis process comprises the following steps:

[0058] The raw materials include iron ore powder 110, coking coal 120, fine coal 410 and small-grain coal 420, of which 35%-45% of raw iron powder, 54%-64% of coking coal, and dust ash 902 returned from the dust collector 900 are supplemented with 1%-3% of a binder 130. After mixed and crushed to 3mm, the iron coking coal 101 is formed in a high-pressure molding device 100.

[0059] Typical but non-limiting contents of the iron powder are: 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%.

[0060] Typical but non-limiting contents of the coking coal are: 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%.

[0061] Typical but non-limiting contents of the binder are: 1%, 2% or 3%.

[0062] The strength performance of the iron coke type of the present invention is described below using experimental data:

[0063] Iron Fan Coking coal Binder <![CDATA[Type coke strength M 40 > Comparative Example 1 30% iron powder 70% coking coal - 70 Comparative Example 2 28% Iron powder 70% coking coal 2% binder 58 Example 1 35% Iron powder 64% coking coal 1% binder 75 Example 2 45% Iron powder 54% coking coal 1% binder 82 Example 3 38% Iron powder 59% coking coal 3% binder 76

[0064] From the above experimental data, it can be seen that the strength of the coke containing the adhesive and the raw material ratio within the scope of the present invention reaches 75 M 40 As mentioned above, if the raw material ratio exceeds the range of the present invention, the strength of the molded coke will be significantly reduced. If no adhesive is used, the strength of the molded coke will also be low. The adhesive of the present invention ensures that the density and shape of the molded iron coke remain unchanged under high-temperature carbonization environment, thereby facilitating the filling of colloids between particles to form a dense carbon skeleton, so that the molded iron coke has high strength.

[0065] After being formed, the shaped iron coking coal 101 enters the drying device 200. The heat source of the drying device is composed of the high-temperature exhaust gas 302 generated by the carbonization furnace and the hot exhaust gas 502 generated by the cooling device. The exhaust gas 202 generated by the drying device enters the dust collector 900 for dust removal.

[0066] The dried iron coke 201 enters the carbonization furnace 300 for high-temperature carbonization, and the circulating coal gas 811 generated by the pyrolysis device is mixed with air as the main combustion gas source of the carbonization furnace.

[0067] The high-temperature iron coke 301 produced by the carbonization furnace enters the heat carrier combined pyrolysis device 400, which consists of two routes of materials to be pyrolyzed, namely, fine coal 410, fine coal bin 430, small-particle coal 420, and small-particle coal pyrolysis filtration device 440. The high-temperature iron coke sent from the carbonization furnace is fully mixed with the pyrolysis and homogeneously carbonized in the heat carrier combined pyrolysis device. A large amount of raw coal gas is generated in the pyrolysis process, which enters the small-particle coal pyrolysis filtration device through the raw coal gas pipeline 402. In the process of passing through the small-particle coal pyrolysis filtration device, the small-particle coal is preliminarily pyrolyzed, and the raw coal gas 441 is filtered and cooled.

[0068] The mixed hot material 401 produced by the heat carrier combined pyrolysis device enters the cooling device 500 for cooling. Part of the circulating exhaust gas 911 introduced by the dust collector 900 enters the cooling device to participate in cooling the hot material and pressure equalization sealing, preventing part of the raw gas from the heat carrier combined pyrolysis device from entering the cooling device.

[0069] The cooled mixed material 501 enters the magnetic separation device 600. After magnetic separation and classification, two products are output: iron coke finished product 610 and semi-coke powder and semi-coke particle mixture 602.

[0070] The mixture of semi-coke powder and semi-coke particles 602 enters the screening device 700 for classification, and two products, semi-coke powder 710 and semi-coke particles 720, are output.

[0071] The raw coal gas 441 outputted from the small-particle coal pyrolysis and filtration device enters the condensation recovery device 800, is condensed and recovered, and then outputs the coal gas 801, which is pressurized by the coal gas blower 810 and then outputs the circulating coal gas 811 to the carbonization furnace.

[0072] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An iron-coke coupled fine coal pyrolysis process, characterized in that: The steps include: a. Mix and crush 35%-45% of raw iron powder, 54%-64% of coking coal and 1%-3% of binder, and then send them to high-pressure molding equipment for molding; b. The formed iron coking coal is dried by a drying device; c. After drying, the iron coking coal enters the carbonization furnace for carbonization. Iron powder is added to the coking coal and high-density iron coking coal is formed through high-pressure molding equipment. The carbonization furnace quickly heats the iron coking coal to the carbonization temperature in an undisturbed environment, so that the colloid formed by the coking coal evenly embedded in the iron coking coal at a certain temperature is fully filled between the particles. The binder ensures that the density and shape of the iron coking coal remain unchanged under the high-temperature carbonization environment, forming iron-containing coke with a dense carbon skeleton; d. The carbonized high-temperature iron coke enters the heat carrier combined pyrolysis device as the first raw material; the fine coal and small-particle coal are processed by the fine coal bin and the small-particle coal pyrolysis filtration device respectively, and then enter the heat carrier combined pyrolysis device as the second and third raw materials; e. The material after pyrolysis by the heat carrier combined pyrolysis device enters the cooling device for cooling; f. The cooled products enter the magnetic separation equipment for magnetic separation, and the finished iron coke products and semi-coke products are output; g. The semi-coke product enters the screening equipment, and the semi-coke powder and semi-coke pellet products are output; An iron-coke coupled fine coal pyrolysis system used in the iron-coke coupled fine coal pyrolysis process comprises: High pressure forming equipment, drying equipment, carbonization furnace, heat carrier combined pyrolysis equipment, cooling equipment, magnetic separation equipment and screening equipment; The high pressure forming equipment is provided with a first feed inlet, a second feed inlet and a third feed inlet, wherein the first feed inlet is connected to the raw material outlet of the iron powder, the second feed inlet is connected to the raw material outlet of the coking coal, and the third feed inlet is used to add a binder and fully mix it with the iron powder and the coking coal in proportion; The feed inlet of the drying device is connected to the discharge port of the high-pressure forming equipment, the first heat source inlet of the drying device is connected to the high-temperature exhaust gas outlet of the carbonization furnace, the second heat source inlet of the drying device is connected to the hot exhaust gas outlet of the cooling device, and the discharge port of the drying device is connected to the feed inlet of the carbonization furnace; The first feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the carbonization furnace, the second feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the final coal bin, the third feed inlet of the heat carrier combined pyrolysis device is connected to the discharge port of the small-particle coal pyrolysis and filtering device, the discharge port of the heat carrier combined pyrolysis device is connected to the feed port of the cooling device, and the air outlet is connected to the air inlet of the small-particle coal pyrolysis and filtering device; The discharge port of the cooling device is connected to the feed port of the magnetic separation device. The discharge port of the magnetic separation device outputs iron coke in one way and is connected to the feed port of the screening device in the other way. The discharge port of the screening device outputs semi-coke powder and semi-coke particles respectively.

2. The iron-coke coupled fine coal pyrolysis process according to claim 1, characterized in that: In step b, the heat source of the drying device is composed of high-temperature exhaust gas generated by the carbonization furnace and hot exhaust gas generated by the cooling device, and the exhaust gas generated by the drying device enters the dust collector for dust removal.

3. The iron-coke coupled fine coal pyrolysis process according to claim 2, characterized in that: The dust produced by the dust collector is sent to the raw material port of the high-pressure forming equipment for recycling. Part of the waste gas produced by the dust collector is discharged into the atmosphere, and the other part enters the cooling device to participate in cooling the hot material and pressure-equalizing sealing.

4. The iron-coke coupled fine coal pyrolysis process according to any one of claims 1 to 3, characterized in that: In step d, the raw coal gas generated by pyrolysis of the heat carrier combined with the pyrolysis device is dedusted, filtered, and cooled by the small-particle coal pyrolysis and filtration device, and then purified by the condensation recovery device to form circulating coal gas, which is sent back to the carbonization furnace for use.

5. The iron-coke coupled fine coal pyrolysis process according to claim 1, characterized in that: In step a, the iron powder is iron concentrate or iron ore powder.

6. The iron-coke coupled fine coal pyrolysis process according to claim 1, characterized in that: It also includes a condensation recovery device, the air inlet of which is connected to the raw coal gas outlet of the small-particle coal pyrolysis and filtration device, and the air outlet of the condensation recovery device is connected to the gas inlet of the carbonization furnace through a gas blower.

7. The iron-coke coupled fine coal pyrolysis process according to claim 1, characterized in that: It also includes a dust collector, the inlet of which is connected to the air outlet of the drying device, the dust ash outlet of the dust collector is connected to the feed inlet of the high-pressure forming equipment, the first air outlet of the dust collector is connected to the atmosphere to discharge part of the exhaust gas into the atmosphere, and the second air outlet of the dust collector is connected to the air inlet of the cooling device through the exhaust gas circulation fan.

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