Coal desulfurizer as well as preparation method and application thereof

Abstract

The invention provides a coal desulfurizing agent as well as a preparation method and application thereof, and belongs to the technical field of coal desulfurization. The coal desulfurizer is prepared from metal chloride and an organic solvent, the mass ratio of the metal chloride to the organic solvent is (0.0020-0.0055): 1; the organic solvent comprises tetrahydronaphthalene and normal hexane. Coal and the coal desulfurizer are mixed and then subjected to microwave treatment, post-treatment and drying, and desulfurized coal is obtained. The coal desulfurizer disclosed by the invention is combined with microwave treatment to desulfurize coal, so that the reduction degree of the sulfur content is not less than 35%, the use of organic solvents can be greatly reduced, the treatment cost and the risk of environmental pollution are reduced, and the requirements of green chemistry are met.

Description

Technical Field

[0001] The present invention relates to the technical field of coal desulfurization, and in particular to a coal desulfurizer, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of the iron and steel industry, the demand for coke has been increasing day by day. In the fields of special equipment manufacturing and special metal material smelting, there are extremely strict index requirements for the sulfur content of hot metal. Corresponding requirements are also applied to the raw materials for smelting hot metal - coke and the quality of coking coal for preparing coke (Fuel, 2020, 280, 18488). At present, there are many pre-combustion desulfurization methods for coal, and the commonly used methods include physical desulfurization method, chemical desulfurization method, and biological desulfurization method. Although the traditional physical desulfurization method is economical and has a simple process, it can only remove inorganic sulfur in coal and cannot remove organic sulfur. Due to the poor stability, long desulfurization time, and difficult actual operation control of the biological desulfurization method, it still remains at the laboratory stage. Therefore, the chemical desulfurization method is currently a relatively effective coal desulfurization method.

[0003] In the chemical desulfurization method, the combination of microwave with acid solution, alkali solution, and oxidant is a relatively effective coal desulfurization method. Wang Jie et al. found that the desulfurization rates of Yutianbao coal and Donglin coal reached 68% and 55.5% respectively after microwave irradiation and pickling with dilute hydrochloric acid, and it was found that microwave can promote the occurrence of sulfur elements in coal to tend to Fe 1-xS and FeS (the phases soluble in dilute hydrochloric acid), so most of them can be removed by dilute hydrochloric acid (Journal of East China University of Chemical Technology, 1990, 01, 45 - 49). In terms of microwave combined with alkali solution, Waanders et al. mixed NaOH with South African coal (mass ratio 3:1), and then irradiated it in a microwave field of 650W for 10 min. The highest desulfurization rate could reach 40%, but they also found that this method would have a negative impact on coal quality (Journal of Physics: Conference Series. IOP Publishing, 2010, 217(1), 1 - 4). In terms of microwave combined with oxidant, Chinese Patent No. CN105132073A discloses a method for desulfurizing high - sulfur coal by microwave combined with oxidant assistant. Through pretreatment with a wetting agent (95% ethanol aqueous solution) and a reaction assistant (a mixed solution of peroxide solution and alkali solution), and placing the coal powder under microwave radiation for reaction. After irradiation for a period of time, washing and filtering can obtain a low - sulfur coal - based product, and the desulfurization rate is 28.34 - 51.14%. In addition, Chinese Patent No. CN105542899A discloses a coal desulfurization method, which mainly realizes the removal of sulfur content in coal by multiple microwave irradiations, including steps of primary microwave radiation, oxidation, secondary microwave radiation and gamma - ray irradiation. Among them, the removal rates of inorganic sulfur and organic sulfur are 38 - 92% and 31 - 84% respectively. Chinese Patent No. CN115055052A discloses an efficient catalytic desulfurizer and its application. It adopts the combination of desulfurizer - adsorbent, with Ca(OH)2 as the main body, and is paired with a trivalent iron compound of MOFs type (catalyzing and adsorbing SO2 in the desulfurization environment), and forms a slurry - phase desulfurization system during application. And it is used to remove sulfur elements from a mixed gas system of SO2 and N2, and the removal rate of gas sulfur content is 91.59 - 98.90%.

[0004] However, the extensive use of acidic and alkaline solutions, the popularization of the application of some special rays and the complex preparation process of MOF materials have high requirements for the cost, industrial process design and environmental protection feasibility of the coal desulfurization industry. Therefore, a coal desulfurization method with wide industrial applicability and engineering - level green environmental protection has become an urgent problem for those skilled in the art to solve. Summary of the Invention

[0005] The purpose of the present invention is to provide a coal desulfurizer, its preparation method and application to solve the problem of high cost of coal desulfurization in the prior art.

[0006] To achieve the above - mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a coal desulfurizer, which is made of metal chloride and organic solvent; the mass ratio of the metal chloride to the organic solvent is 0.0020 - 0.0055:1; the organic solvent includes tetralin and n - hexane.

[0008] Preferably, the metal chloride includes nickel chloride and / or iron chloride; the mass ratio of the tetralin to the n - hexane is 0.75 - 1.50:1.

[0009] The present invention also provides a preparation method of the above - mentioned coal desulfurizer, which includes the following steps: mixing the metal chloride and n - hexane, and then adding tetralin for heating and mixing to obtain the coal desulfurizer.

[0010] Preferably, the temperature of the heating and mixing is 40 - 60 °C, and the time is 15 - 30 min.

[0011] The present invention also provides an application of the above - mentioned coal desulfurizer in coal.

[0012] Preferably, it includes the following steps: mixing the coal and the coal desulfurizer, and then performing microwave treatment, post - treatment and drying to obtain the desulfurized coal.

[0013] Preferably, the mass ratio of the coal to the coal desulfurizer is 1.5 - 2.1:1.

[0014] Preferably, when performing the microwave treatment, the microwave frequency is 1000 - 3000 MHz, and the time of the microwave treatment is 5 - 15 min.

[0015] Preferably, the post - treatment is carried out in a nitrogen atmosphere.

[0016] Preferably, the pressure during the post - treatment is 0.5 - 1.8 MPa, the temperature of the post - treatment is 200 - 400 °C, and the time of the post - treatment is 30 - 150 min.

[0017] Advantages of the present invention:

[0018] Compared with the traditional organic solvent method for desulfurization, the coal desulfurizer of the present invention combines microwave treatment to desulfurize coal, which can greatly reduce the use of organic solvents, lower the treatment cost and the risk of environmental pollution, and meet the requirements of green chemistry.

[0019] When the coal desulfurizer of the present invention is used for desulfurization, the reaction conditions are relatively mild, which reduces the energy consumption and the requirements for equipment. The mild conditions make the process easier to control, improve the safety, and at the same time reduce the damage to the original structure of the coal. Specific embodiments

[0020] The present invention provides a coal desulfurizer, which is made of metal chloride and organic solvent; the mass ratio of the metal chloride to the organic solvent is 0.0020 - 0.0055:1; the organic solvent includes tetralin and n-hexane.

[0021] In the present invention, the mass ratio of the metal chloride to the organic solvent is preferably 0.0030 - 0.0045:1, and more preferably 0.0035 - 0.0045:1.

[0022] In the present invention, the metal chloride includes nickel chloride and / or iron chloride; the mass ratio of the tetralin to the n-hexane is 0.75 - 1.50:1, preferably 1.0 - 1.5:1, and more preferably 1.25 - 1.5:1.

[0023] In the present invention, the tetralin in the coal desulfurizer can open up the internal molecular channels of the coal and can desulfurize the coal under mild conditions.

[0024] The present invention also provides a preparation method of the above-mentioned coal desulfurizer, which includes the following steps: mixing the metal chloride and n-hexane, and then adding tetralin for heating and mixing to obtain the coal desulfurizer.

[0025] In the present invention, the mixing is carried out at room temperature, and the mixing time is 5 - 20 min, preferably 10 - 20 min, and more preferably 15 - 20 min.

[0026] In the present invention, the temperature of the heating and mixing is 40 - 60 °C, preferably 40 °C, 50 °C, 60 °C; the time is 15 - 30 min, preferably 15 min, 18 min, 20 min, 25 min, 30 min.

[0027] The present invention also provides an application of the above-mentioned coal desulfurizer in coal.

[0028] In the present invention, it includes the following steps: mixing the coal and the coal desulfurizer, then carrying out microwave treatment, post-treatment and drying to obtain the desulfurized coal.

[0029] In the present invention, the coal is preferably crushed and then mixed with the coal desulfurizer.

[0030] In the present invention, the mass ratio of the coal to the coal desulfurizer is 1.5 - 2.1:1, preferably 1.7 - 1.9:1, and more preferably 1.75 - 1.85:1.

[0031] In the present invention, during the microwave treatment, the microwave frequency is 1000 - 3000 MHz, preferably 1500 - 2500 MHz, and more preferably 2250 - 2450 MHz; the time of the microwave treatment is 5 - 15 min, preferably 7 - 12 min, and more preferably 8 - 10 min.

[0032] In the present invention, the post-treatment is carried out in a nitrogen atmosphere.

[0033] In the present invention, during the post-treatment, the pressure is 0.5 - 1.8 MPa, preferably 0.8 - 1.2 MPa, and more preferably 0.9 - 1.1 MPa; the temperature of the post-treatment is 200 - 400 °C, preferably 250 - 350 °C, and more preferably 280 - 320 °C; the time of the post-treatment is 30 - 150 min, preferably 60 - 100 min, and more preferably 70 - 90 min.

[0034] In the present invention, metal chlorides in the desulfurizer promote the removal of sulfur elements in an ionic state. Microwave treatment can strengthen the dispersion of coal particles and the effect of internal molecular mass transfer, combine with tetralin to open up the internal molecular channels of coal, and can treat coal under the mild conditions of low-pressure nitrogen and temperature external fields, improving the overall mass transfer effect and the reactivity of sulfur elements. It can achieve a significant reduction in sulfur content while ensuring the original coal rank properties of medium and high sulfur coal, and the degree of sulfur content reduction is not less than 35%.

[0035] The technical solutions provided by the present invention will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0036] Example 1

[0037] Weigh the above raw materials according to the mass ratio of industrial-grade tetralin to industrial-grade n-hexane of 0.75:1 and the mass ratio of nickel chloride to organic solvent of 0.0020:1. Mix nickel chloride and industrial-grade n-hexane, stir at room temperature for 5 min, then add industrial-grade tetralin, heat to 40 °C, and stir at this temperature for 15 min to obtain a coal desulfurizer.

[0038] Mix the medium and high sulfur coal (30 g) crushed to 80 mesh with the above coal desulfurizer at a mass ratio of 1.70:1, and then treat it with microwave at a frequency of 2250 MHz for 8 min. After the microwave treatment, transfer it to a high-pressure reactor with a volume of 350 mL, introduce nitrogen, displace and pressurize with nitrogen. Control the pressure in the reactor at 0.8 MPa, set the programmed heating rate to rise to 280 °C at 5 °C / min, react at 280 °C for 60 min, and after the reaction, naturally cool to room temperature in a closed state. Open the reactor, separate the solid and liquid products, and dry the separated solid at 105 °C for 10 h to obtain desulfurized coal.

[0039] Example 2

[0040] Weigh the above raw materials according to the mass ratio of industrial-grade tetralin to industrial-grade n-hexane of 1.0:1 and the mass ratio of nickel chloride to organic solvent of 0.0030:1. Mix nickel chloride and industrial-grade n-hexane, stir at room temperature for 10 min, then add industrial-grade tetralin, heat to 50 °C, and stir at this temperature for 18 min to obtain a coal desulfurizer.

[0041] Mix the medium and high sulfur coal (30 g) crushed to 80 mesh with the above coal desulfurizer at a mass ratio of 1.75:1, and then treat it with microwave at a frequency of 2300 MHz for 8.5 min. After the microwave treatment, transfer it to a high-pressure reactor with a volume of 350 mL, introduce nitrogen, displace and pressurize with nitrogen. Control the pressure in the reactor at 0.9 MPa, set the programmed heating rate to rise to 290 °C at 5 °C / min, react at 290 °C for 70 min, and after the reaction, naturally cool to room temperature in a closed state. Open the reactor, separate the solid and liquid products, and dry the separated solid at 105 °C for 10 h to obtain desulfurized coal.

[0042] Example 3

[0043] Weigh the above raw materials according to the mass ratio of industrial-grade tetralin to industrial-grade n-hexane of 1.25:1 and the mass ratio of ferric chloride to organic solvent of 0.0035:1. Mix ferric chloride and industrial-grade n-hexane, stir at room temperature for 15 min, then add industrial-grade tetralin, heat to 60 °C, and stir at this temperature for 25 min to obtain a coal desulfurizer.

[0044] Mix the medium-high sulfur coal (30 g) crushed to 80 mesh with the above coal desulfurizer in a mass ratio of 1.80:1, then treat it with microwave at a frequency of 2350 MHz for 9 min. After the microwave treatment, transfer it to a high-pressure reactor with a volume of 350 mL, introduce nitrogen, displace and pressurize with nitrogen. Control the pressure in the reactor at 1.0 MPa, set the programmed heating rate to rise to 300 °C at 5 °C / min, react at 300 °C for 80 min. After the reaction, naturally cool to room temperature under a closed state, open the reactor, separate the solid and liquid products, and dry the separated solid at 105 °C for 10 h to obtain the desulfurized coal.

[0045] Example 4

[0046] Weigh the above raw materials according to the mass ratio of industrial-grade tetralin to industrial-grade n-hexane of 1.50:1 and the mass ratio of ferric chloride to organic solvent of 0.0045:1. Mix ferric chloride and industrial-grade n-hexane, stir at room temperature for 20 min, then add industrial-grade tetralin, heat to 60 °C, and stir at this temperature for 30 min to obtain the coal desulfurizer.

[0047] Mix the medium-high sulfur coal (30 g) crushed to 80 mesh with the above coal desulfurizer in a mass ratio of 1.85:1, then treat it with microwave at a frequency of 2450 MHz for 9.5 min. After the microwave treatment, transfer it to a high-pressure reactor with a volume of 350 mL, introduce nitrogen, displace and pressurize with nitrogen. Control the pressure in the reactor at 1.1 MPa, set the programmed heating rate to rise to 310 °C at 5 °C / min, react at 310 °C for 90 min. After the reaction, naturally cool to room temperature under a closed state, open the reactor, separate the solid and liquid products, and dry the separated solid at 105 °C for 10 h to obtain the desulfurized coal.

[0048] Example 5

[0049] Weigh the above raw materials according to the mass ratio of industrial-grade tetralin to industrial-grade n-hexane of 1.25:1 and the mass ratio of ferric chloride to organic solvent of 0.0055:1. Mix ferric chloride and industrial-grade n-hexane, stir at room temperature for 15 min, then add industrial-grade tetralin, heat to 60 °C, and stir at this temperature for 25 min to obtain the coal desulfurizer.

[0050] Mix the medium-high sulfur coal (30 g) crushed to 80 mesh with the above-mentioned coal desulfurizer at a mass ratio of 1.90:1, and then treat it with microwave at a frequency of 2400 MHz for 10 min. After the microwave treatment, transfer it to a high-pressure reactor with a volume of 350 mL, introduce nitrogen, displace and pressurize with nitrogen. Control the pressure in the reactor at 1.2 MPa, set the programmed heating rate to rise to 320 °C at 5 °C / min, react at 320 °C for 100 min, and after the reaction, naturally cool to room temperature under a closed state. Open the reactor, separate the solid and liquid products, and dry the separated solid at 105 °C for 10 h to obtain the desulfurized coal.

[0051] Table 1 shows the performance test results of the medium-high sulfur coal used in Examples 1 to 5. Among them, the proximate analysis of the coal is based on Chinese standard (GB / T 212-2008), and the total sulfur determination is based on Chinese standard (GB / T 214-2007):

[0052] Table 1 Performance test results of the medium-high sulfur coal used in Examples 1 to 5

[0053]

[0054]

[0055] Test the desulfurized coal obtained in Examples 1 to 5, and the results are shown in Table 2. Among them, the total sulfur determination is based on Chinese standard (GB / T 214-2007):

[0056] Table 2 Test results of the desulfurized coal obtained in Examples 1 to 5

[0057] Project Example 1 Example 2 Example 3 Example 4 Example 5 <![CDATA[S t，ad (%)]]> 0.98 0.88 0.86 0.81 0.89 Removal rate (%) 35.52 42.11 43.42 46.71 41.45

[0058] As can be seen from Table 2, by using the coal desulfurizer of the present invention and combining with the desulfurization method, the total sulfur S can be significantly reduced t,ad , and the desulfurization rate can reach 46.71%.

[0059] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A coal desulfurizer, characterized in that: The coal desulfurizer is made of metal chloride and organic solvent; the mass ratio of the metal chloride to the organic solvent is 0.0020-0.0055:1; and the organic solvent contains tetralin and n-hexane.

2. The coal desulfurizer according to claim 1, characterized in that: The metal chloride comprises nickel chloride and / or ferric chloride; the mass ratio of tetralin to n-hexane is 0.75-1.50:

1.

3. The method for preparing the coal desulfurizer according to claim 1 or 2, characterized in that: The method comprises the following steps: mixing metal chloride and normal hexane, adding tetralin, heating and mixing, and obtaining a coal desulfurizing agent.

4. The method for preparing a coal desulfurizer according to claim 3, characterized in that: The temperature of the heating and mixing is 40-60° C., and the time is 15-30 minutes.

5. Use of the coal desulfurizer according to claim 1 or 2 in coal.

6. The use of the coal desulfurizer in coal according to claim 5, characterized in that: The method comprises the following steps: mixing coal and a coal desulfurizer, performing microwave treatment, post-treatment and drying to obtain desulfurized coal.

7. The use of the coal desulfurizer in coal according to claim 6, characterized in that: The mass ratio of the coal to the coal desulfurizer is 1.5-2.1:

1.

8. Use of the coal desulfurizer according to claim 6 or 7 in coal, characterized in that: The microwave frequency during the microwave treatment is 1000-3000 MHz, and the microwave treatment time is 5-15 minutes.

9. The use of the coal desulfurizer in coal according to claim 8, characterized in that: The post-treatment was carried out in a nitrogen atmosphere.

10. The use of the coal desulfurizer in coal according to claim 9, characterized in that: The post-treatment pressure is 0.5-1.8 MPa, the post-treatment temperature is 200-400° C., and the post-treatment time is 30-150 min.

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