Coal-based porous material and preparation method and application thereof

Abstract

This invention relates to a coal-based porous material, its preparation method, and its application. The coal-based porous material comprises the following steps: calcining high-ash coal at 900–1100°C under an inert gas atmosphere and then cooling to obtain coal char A; calcining coal char A at 800–1200°C under a complex atmosphere I and then cooling to obtain substance B; mixing substance B with ruthenium dioxide and stirring to obtain substance C; calcining substance C at 200–500°C under a complex atmosphere II and then cooling to obtain substance D; and allowing substance D to stand at 100–280°C under an inert gas atmosphere to obtain the coal-based porous material. This invention utilizes the synergistic effect of O2, NH3, H2O, and CO2 in a complex atmosphere of low concentrations of O2 or NH3 and high concentrations of H2O and CO2, as well as the differences in their reaction rates, to create main channels with pore sizes of 10–50 nm and abundant auxiliary channels with pore sizes less than 10 nm connected to the main channels in the prepared coal-based porous material. This forms a distinct pore structure, resulting in a larger specific surface area and reduced fluid flow resistance. Since coal-based porous materials can adsorb thiophene, the distinct pore structure of the coal-based porous material prepared by this invention significantly improves its adsorption capacity for thiophene.

Description

Technical Field

[0001] This invention belongs to the field of crude benzene refining technology, specifically relating to a coal-based porous material, its preparation method, and its application. Background Technology

[0002] Crude benzene from coking processes contains 0.6–2.2% thiophene and 0.3–0.7% carbon disulfide and other sulfur-containing substances. High thiophene content can poison catalysts in some benzene synthesis reactions; therefore, thiophene content is a major standard for measuring the quality of pure benzene. Various countries have relevant standards for the thiophene content in refined benzene. However, thiophene itself is a very valuable chemical substance, widely used not only in the organic synthesis of hydrocarbons, aromatics, ketones, alcohols, carboxylic acids, and amino acids, but also in the manufacture of various synthetic drugs, photosensitive materials, and smectic liquid crystal compounds.

[0003] Currently, thiophene is mainly converted into saturated hydrocarbons through multi-stage catalytic hydrogenation, followed by removal by distillation. This method suffers from low feedstock utilization, complex process flow, high energy consumption, and inefficient utilization of thiophene. Specifically: crude benzene must first be separated into heavy and light benzene via a multi-stage evaporator, and only light benzene can be catalytically hydrogenated; because crude benzene contains unsaturated hydrocarbons that readily polymerize, leading to catalyst deactivation due to carbon buildup, a pre-hydrogenation stage is necessary to remove these unsaturated hydrocarbons; aromatics and non-aromatics are separated through extractive distillation, requiring the introduction of an extractant that must be recovered and reused. Furthermore, due to the 4.1°C difference in boiling points between thiophene and benzene, and their relative volatility a = 1.1, complete separation using conventional fractionation methods results in extremely high steam consumption.

[0004] Adsorption is a low-cost and simple method for removing thiophene, but the adsorbents used have the following problems: 1. The active components are unevenly distributed, mostly concentrated on the surface of the carrier, resulting in poor desulfurization performance; 2. These adsorbents, when used in the desulfurization of gasoline / diesel with a thiophene content of 500–2000 μg / g, still suffer from frequent regeneration and poor desulfurization performance, and are even more difficult to apply to coking crude benzene with a high thiophene content of 10000–22000 μg / g. China Petroleum & Chemical Corporation (publication number CN101433817A) has prepared a desulfurization adsorbent, which consists of alumina as a binder, zinc oxide as a carrier, contact with a complexing agent solution, and then loading a metal promoter. It exhibits high activity for fuel oil desulfurization. However, during the preparation process, metal ions easily clog the pores of the metal oxide, causing the loaded active components to accumulate on the surface and unable to enter the pores to provide active sites, thus reducing adsorption and desulfurization performance and making it difficult to apply to industrial production. Coal-based porous materials have good pore structure and surface properties, and can be used to adsorb target molecules such as thiophene. Moreover, coal-based porous materials also have high stability and regeneration capacity, which is in line with the concept of green environmental protection. Summary of the Invention

[0005] The purpose of this invention is to provide a coal-based porous material, its preparation method, and its application. This coal-based porous material forms a main channel with a larger pore size and an auxiliary channel with a smaller pore size, forming a layered pore structure, which improves the adsorption capacity of thiophene in crude benzene. At the same time, after high-temperature calcination, the coal-based porous material forms acid sites, and the pore structure and acid-base interaction work together to adsorb thiophene, resulting in a higher adsorption rate and adsorption capacity for thiophene.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a coal-based porous material, characterized by comprising the following steps:

[0008] Step 1): Calcine the high-ash coal at 900-1100℃ under inert gas conditions and then cool it to obtain coal char A;

[0009] Step 2): Coal coke A is calcined at 800-1200℃ in a complex atmosphere and then cooled to obtain substance B;

[0010] Step 3): Mix and stir substance B with ruthenium dioxide to obtain substance C; calcine substance C at 200-500℃ under complex atmosphere II and then cool to obtain substance D;

[0011] Step 4): Let substance D stand at 100-280℃ under inert gas conditions to obtain coal-based porous material.

[0012] Furthermore, the first complex atmosphere mentioned in step 2) is a mixture of O2, H2O, CO2 and a balance gas or a mixture of NH3, H2O, CO2 and a balance gas; the second complex atmosphere mentioned in step 3) is a mixture of H2 and a balance gas.

[0013] Furthermore, the balancing gas is N2; the volume fraction of O2 in complex atmosphere one is 0.2-0.6%, the volume fraction of H2O is 40-60%, and the volume fraction of CO2 is 30-40%; or the volume fraction of NH3 in complex atmosphere one is 1-6%, the volume fraction of H2O is 40-65%, and the volume fraction of CO2 is 30-40%; and the volume fraction of H2 in complex atmosphere two is 60-80%.

[0014] Furthermore, in step 3), the mass ratio of substance B to ruthenium dioxide is 500–600:1.

[0015] Furthermore, in step 4), the substance D is pressed under the action of the binder, and then the substance D is left to stand at 100-280°C under inert gas conditions; the binder is asphalt, and the pressing pressure is 0.2-0.4 MPa.

[0016] Furthermore, the cooling described in steps 1) and 3) is carried out under inert gas protection.

[0017] Furthermore, the mass fraction of SiO2 in the high-ash coal is 50-70%, the mass fraction of Al2O3 is 20-40%, the mass fraction of MgO is 5-20%, and the mass fraction of B2O3 is 0.05-2%.

[0018] A coal-based porous material is prepared using the method described above.

[0019] Furthermore, the coal-based porous material contains a main channel with a pore size of 10–50 nm and auxiliary channels with a pore size of less than 10 nm that are connected to the main channel.

[0020] An application of a coal-based porous material, wherein the method for adsorbing thiophene in crude benzene by the coal-based porous material is as follows: the coal-based porous material and crude benzene are subjected to static adsorption; the mass ratio of the coal-based porous material to crude benzene is 1:20-24.

[0021] The beneficial effects of this invention are:

[0022] This invention utilizes the synergistic effect of O2, NH3, H2O, and CO2 in a complex atmosphere of low concentrations of O2 or NH3 and high concentrations of H2O and CO2, as well as the differences in their reaction rates, to create main channels with pore sizes of 10–50 nm and abundant auxiliary channels with pore sizes less than 10 nm connected to the main channels in the prepared coal-based porous material. This forms a distinct pore structure, resulting in a larger specific surface area and reduced fluid flow resistance. Since coal-based porous materials can adsorb thiophene, the distinct pore structure of the coal-based porous material prepared by this invention significantly improves its adsorption capacity for thiophene.

[0023] The coal-based porous material prepared by this invention is rich in hydroxyl and carboxyl groups on its surface. These hydroxyl and carboxyl groups can effectively prevent the cohesion of ultrafine hydrated ruthenium dioxide powder, thereby achieving high dispersibility of ruthenium dioxide powder and greatly improving the adsorption capacity of the coal-based porous material of this invention for thiophene.

[0024] This invention forms SiO2-MgO and Al2O3-B2O3 acidic sites in high-ash coal after high-temperature calcination. Thiophene is adsorbed through acid-base interaction. The synergistic effect of the pore structure and acid-base interaction further improves the adsorption of thiophene by the coal-based porous material of this invention. Detailed Implementation

[0025] The present invention will be further described below with reference to embodiments thereof.

[0026] After adsorbing thiophene from crude benzene using the coal-based porous material prepared according to this invention, the mass fraction of thiophene in the crude benzene solution was detected by gas chromatography. Adsorption equilibrium was reached when the difference in the mass fraction of thiophene between two consecutive measurements did not exceed 0.1%. The removal rate and adsorption capacity of thiophene in the crude benzene were calculated based on the change in the mass fraction of thiophene. In this invention, the mass fraction of thiophene in the crude benzene was selected as 0.1500%.

[0027] Thiophene removal rate = (1 - substance C) 吸附后 / Substance C 吸附前 )×100%

[0028] Thiophene adsorption capacity = m 苯 ×(Substance C) 吸附前 -Substance C 吸附后 ) / m G

[0029] Among them, substance C 吸附前 The mass fraction of thiophene in the crude benzene solution before the adsorption of thiophene by the coal-based porous material of this invention;

[0030] Substance C 吸附后 The mass fraction of thiophene in the crude benzene solution after the adsorption of thiophene by the coal-based porous material of this invention;

[0031] m 苯 The mass of the crude benzene solution, in grams;

[0032] m G The mass of the coal-based porous material in this invention is expressed in grams.

[0033] Gas chromatography detection conditions: detector temperature 310℃, injection port temperature 260℃, segmented temperature increase, heating rate: 2℃ / min, 70℃ for 5 min, 100℃ for 6 min.

[0034] High-ash coal refers to coal whose ash composition, as determined by GB / T1574-2007, contains 50-70% SiO2, 20-40% Al2O3, 5-20% MgO, and 0.05-2% B2O3 by mass. Ultrafine hydrated ruthenium dioxide powder meets the requirements of YS / T598-2006 standard, but no requirements are specified for cadmium content. Pitch refers to coal tar pitch with a coking value of 60-70% and a softening point of 75℃-100℃. For complex atmosphere I and complex atmosphere II, a steady-state mode in which the gas flows continuously from bottom to top through a fixed bed composed of solid particles is preferred.

[0035] Example 1

[0036] The preparation method of the coal-based porous material in this embodiment includes the following steps: High-ash coal with a diameter less than 1 mm is calcined at 900°C under an argon atmosphere for 60 minutes, and then naturally cooled in an argon atmosphere to obtain coal char A. A is then allowed to stand at 1200°C under a complex atmosphere I for 20 minutes, and then cooled with an ice-water mixture to obtain substance B. Complex atmosphere I is a mixture of O2, H2O, CO2, and N2, with volume fractions of O2, H2O, CO2, and N2 of 0.2%, 40%, 30%, and 29.8%, respectively. Substance B is mixed with ultrafine ruthenium dioxide powder and stirred for 2 hours to obtain substance C. Substance C is then allowed to stand at 200°C under a complex atmosphere II for 30 minutes, and then naturally cooled in a nitrogen atmosphere to obtain substance D. The mass ratio of substance B to ruthenium dioxide is 600:1. Complex atmosphere II is a mixture of N2 and H2, with volume fractions of N2 and H2 of 40% and 60%, respectively. Using asphalt as a binder, material D is pressed into spherical shapes with a diameter of 6 mm or rods with a diameter of 6 mm and a length of 10 mm. These are then left to stand at 100°C under an argon atmosphere for 60 minutes to obtain the coal-based porous material. The pressing pressure is 0.2 MPa.

[0037] The coal-based porous material prepared in this embodiment is prepared by the above method. The coal-based porous material prepared in this embodiment includes abundant main channels with a pore size of 10-40 nm and abundant auxiliary channels with a pore size of less than 10 nm connected to the main channels.

[0038] In this embodiment, a static adsorption experiment was conducted on the coal-based porous material and crude benzene to adsorb thiophene. The coal-based porous material and crude benzene were placed in a round-bottom flask, sealed, and mixed thoroughly. Thiophene removal was carried out by stirring at 25°C. The mass fraction of thiophene in the crude benzene solution was detected by gas chromatography. Adsorption equilibrium was reached when the difference in the mass fraction of thiophene between two consecutive measurements did not exceed 0.1%. The removal rate and adsorption capacity of thiophene were calculated based on the change in the mass fraction of thiophene. The mass ratio of coal-based porous material to crude benzene was 1:22.

[0039] The thiophene removal rate of the coal-based porous material prepared in this embodiment is 81%, and the thiophene adsorption capacity is 26.7 mg / g.

[0040] Example 2

[0041] The preparation method of the coal-based porous material in this embodiment includes the following steps: High-ash coal with a diameter less than 1 mm is calcined at 1100°C under an argon atmosphere for 20 minutes, and then naturally cooled in a nitrogen atmosphere to obtain coal char A. A is then allowed to stand at 800°C under a complex atmosphere I for 130 minutes, and then cooled with an ice-water mixture to obtain substance B. Complex atmosphere I is a mixture of NH3, H2O, CO2, and N2, with volume fractions of NH3, H2O, CO2, and N2 of 6%, 40%, 40%, and 14%, respectively. Substance B is mixed and stirred with ultrafine ruthenium dioxide powder in water for 2 hours to obtain substance C. Substance C is then allowed to stand at 400°C under a complex atmosphere II for 40 minutes, and then naturally cooled in a nitrogen atmosphere to obtain substance D. The mass ratio of substance B to ruthenium dioxide is 520:1. Complex atmosphere II is a mixture of N2 and H2, with volume fractions of N2 and H2 of 30% and 70%, respectively. Using asphalt as a binder, material D is pressed into spheres with a diameter of 8 mm or rods with a diameter of 8 mm and a length of 10 mm. These are then left to stand at 250°C under an argon atmosphere for 60 minutes to obtain a coal-based porous material. The pressing pressure is 0.4 MPa.

[0042] The coal-based porous material prepared in this embodiment is prepared by the above method. The coal-based porous material prepared in this embodiment includes a main channel with a pore size of 10-30 nm and a large number of auxiliary channels with a pore size of less than 10 nm connected to the main channel.

[0043] In this embodiment, a static adsorption experiment was conducted on the coal-based porous material and crude benzene to adsorb thiophene. The coal-based porous material and crude benzene were placed in a round-bottom flask, sealed, and mixed thoroughly. Thiophene removal was carried out by stirring at 25°C. The mass fraction of thiophene in the crude benzene solution was detected by gas chromatography. Adsorption equilibrium was reached when the difference in the mass fraction of thiophene between two consecutive measurements did not exceed 0.1%. The removal rate and adsorption capacity of thiophene were calculated based on the change in the mass fraction of thiophene. The mass ratio of coal-based porous material to crude benzene was 1:22.

[0044] The thiophene removal rate of the coal-based porous material prepared in this embodiment is 79%, and the thiophene adsorption capacity is 26.1 mg / g.

[0045] Example 3

[0046] The preparation method of the coal-based porous material in this embodiment includes the following steps: High-ash coal with a diameter less than 1 mm is calcined at 1100°C under an argon atmosphere for 40 minutes, and then naturally cooled in an argon atmosphere to obtain coal char A. A is then allowed to stand at 1050°C under a complex atmosphere I for 90 minutes, and then cooled with an ice-water mixture to obtain substance B. Complex atmosphere I is a mixture of NH3, H2O, CO2, and N2, with volume fractions of NH3, H2O, CO2, and N2 of 1%, 65%, 30%, and 4%, respectively. Substance B is mixed with ultrafine ruthenium dioxide powder and stirred for 1 hour to obtain substance C. Substance C is then allowed to stand at 500°C under a complex atmosphere II for 60 minutes, and then naturally cooled in an argon atmosphere to obtain substance D. The mass ratio of substance B to ruthenium dioxide is 590:1. Complex atmosphere II is a mixture of N2 and H2, with volume fractions of N2 and H2 of 30% and 70%, respectively. Using asphalt as a binder, material D is pressed into spheres with a diameter of 10 mm or rods with a diameter of 10 mm and a length of 6 mm. These are then left to stand at 150°C under an argon atmosphere for 40 minutes to obtain the coal-based porous material. The pressing pressure is 0.4 MPa.

[0047] The coal-based porous material prepared in this embodiment is prepared by the above method. The coal-based porous material prepared in this embodiment includes a main channel with a pore size of 10-30 nm and a large number of auxiliary channels with a pore size of less than 10 nm connected to the main channel.

[0048] In this embodiment, a static adsorption experiment was conducted on the coal-based porous material and crude benzene to adsorb thiophene. The coal-based porous material and crude benzene were placed in a round-bottom flask, sealed, and mixed thoroughly. Thiophene removal was carried out by stirring at 25°C. The mass fraction of thiophene in the crude benzene solution was detected by gas chromatography. Adsorption equilibrium was reached when the difference in the mass fraction of thiophene between two consecutive measurements did not exceed 0.1%. The removal rate and adsorption capacity of thiophene were calculated based on the change in the mass fraction of thiophene. The mass ratio of coal-based porous material to crude benzene was 1:20.

[0049] The thiophene removal rate of the coal-based porous material prepared in this embodiment is 75%, and the thiophene adsorption capacity is 22.5 mg / g.

[0050] Example 4

[0051] The preparation method of the coal-based porous material in this embodiment includes the following steps: High-ash coal with a diameter less than 1 mm is calcined at 1050°C under an argon atmosphere for 30 minutes, and then naturally cooled in an argon atmosphere to obtain coal char A. A is then allowed to stand at 1200°C under a complex atmosphere I for 35 minutes, and then cooled with an ice-water mixture to obtain substance B. Complex atmosphere I is a mixture of O2, H2O, CO2, and N2, with volume fractions of O2, H2O, CO2, and N2 of 0.6%, 60%, 38%, and 1.4%, respectively. Substance B is mixed with ultrafine ruthenium dioxide powder and stirred for 2 hours to obtain substance C. Substance C is then allowed to stand at 360°C under a complex atmosphere II for 60 minutes, and then naturally cooled in an argon atmosphere to obtain substance D. The mass ratio of substance B to ruthenium dioxide is 500:1. Complex atmosphere II is a mixture of N2 and H2, with volume fractions of N2 and H2 of 20% and 80%, respectively. Using asphalt as a binder, material D is pressed into spherical shapes with a diameter of 6 mm or rods with a diameter of 6 mm and a length of 6 mm. These are then left to stand at 280°C under an argon atmosphere for 30 minutes to obtain the coal-based porous material. The pressing pressure is 0.3 MPa.

[0052] The coal-based porous material prepared in this embodiment is prepared by the above method. The coal-based porous material prepared in this embodiment includes a large number of main channels with a pore size of 25-50 nm and abundant auxiliary channels with a pore size of less than 10 nm connected to the main channels.

[0053] In this embodiment, a static adsorption experiment was conducted on the coal-based porous material and crude benzene to adsorb thiophene. The coal-based porous material and crude benzene were placed in a round-bottom flask, sealed, and mixed thoroughly. Thiophene removal was carried out by stirring at 25°C. The mass fraction of thiophene in the crude benzene solution was detected by gas chromatography. Adsorption equilibrium was reached when the difference in the mass fraction of thiophene between two consecutive measurements did not exceed 0.1%. The removal rate and adsorption capacity of thiophene were calculated based on the change in the mass fraction of thiophene. The mass ratio of coal-based porous material to crude benzene was 1:24.

[0054] The thiophene removal rate of the coal-based porous material prepared in this embodiment is 98%, and the thiophene adsorption capacity is 35.3 mg / g.

Claims

1. A method for preparing a coal-based porous material, characterized in that, Includes the following steps: Step 1): Calcine the high-ash coal at 900-1100℃ under inert gas conditions and then cool it to obtain coal char A; Step 2): Coal coke A is calcined at 800-1200℃ in a complex atmosphere and then cooled to obtain substance B; Step 3): Mix and stir substance B with ruthenium dioxide to obtain substance C; calcine substance C at 200-500℃ under complex atmosphere II and then cool to obtain substance D; Step 4): Let substance D stand at 100-280℃ under inert gas conditions to obtain coal-based porous material; Step 2) The first complex atmosphere is a mixture of O2, H2O, CO2 and a balance gas, or a mixture of NH3, H2O, CO2 and a balance gas; Step 3) The second complex atmosphere is a mixture of H2 and a balance gas. The balancing gas is N2; the volume fraction of O2 in complex atmosphere one is 0.2-0.6%, the volume fraction of H2O is 40-60%, and the volume fraction of CO2 is 30-40%; or the volume fraction of NH3 in complex atmosphere one is 1-6%, the volume fraction of H2O is 40-65%, and the volume fraction of CO2 is 30-40%; the volume fraction of H2 in complex atmosphere two is 60-80%.

2. The method for preparing coal-based porous materials according to claim 1, characterized in that, The mass ratio of substance B to ruthenium dioxide in step 3) is 500-600:

1.

3. The method for preparing coal-based porous materials according to claim 1, characterized in that, In step 4), the substance D is pressed under the action of the binder, and then the substance D is left to stand at 100-280°C under inert gas conditions. The binder is asphalt, and the pressing pressure is 0.2 to 0.4 MPa.

4. The method for preparing coal-based porous materials according to claim 1, characterized in that, The cooling described in steps 1) and 3) is carried out under inert gas protection.

5. The method for preparing coal-based porous materials according to claim 1, characterized in that, The high-ash coal contains 50-70% SiO2, 20-40% Al2O3, 5-20% MgO, and 0.05-2% B2O3 by mass.

6. A coal-based porous material, characterized in that, Prepared using the method described in any one of claims 1 to 5.

7. The coal-based porous material according to claim 6, characterized in that, This coal-based porous material contains a main channel with a pore size of 10–50 nm and auxiliary channels with a pore size of less than 10 nm that are connected to the main channel.

8. An application of the coal-based porous material as described in claim 6, characterized in that, The method for adsorbing thiophene from crude benzene using the coal-based porous material is as follows: the coal-based porous material is statically adsorbed with crude benzene; the mass ratio of the coal-based porous material to crude benzene is 1:20-24.