Coke reinforcing agent based on saturated activated carbon and application of coke reinforcing agent in tamping coke oven

Abstract

The invention relates to the technical field of coking solid waste recycling and coke quality improvement, in particular to a preparation method of a coke reinforcing agent based on saturated activated carbon, which comprises the following steps: stirring saturated powdered activated carbon adsorbing sewage by using a mixed acid solution containing 3-8wt% of HCl and 0.5-1.5 wt% of HF at 50-70 DEG C for 1-3 hours, then washing until the pH value is 6.0-7.0 to obtain PAC with the ash content of less than or equal to 4%, and drying to obtain the coke reinforcing agent based on saturated activated carbon. PAC subjected to deep ash removal is soaked in an aqueous solution containing 4-6 wt% of Ca (OH) and 1-3 wt% of aluminum dihydrogen phosphate for 20-40 min, a passivation layer is formed on the surface of PAC after drying is conducted at the temperature of 100-150 DEG C, adsorbed organic matter is converted into a pore forming agent through chemical ash removal and surface modification, conversion from waste pollution loading to performance auxiliaries is achieved, complex regeneration equipment is not needed in the process, and the method is simple and convenient to operate and low in cost. The adsorption characteristic of the saturated PAC is directly utilized, a closed-loop system of wastewater treatment, solid waste value increment and coke upgrading is constructed, and the treatment problem of the saturated PAC is fundamentally solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coking solid waste resource utilization and coke quality improvement, in particular to a coke enhancer based on saturated activated carbon and its application in stamp-charged coke ovens. BACKGROUND

[0002] It is well known that saturated PAC after adsorbing coking wastewater has significant defects in traditional disposal methods due to the loading of organic matters such as tar, phenols, polycyclic aromatic hydrocarbons and inorganic ash. The landfill method is costly and occupies land, and the incineration method consumes high energy and destroys the structure of activated carbon. Existing regeneration technologies are difficult to efficiently restore the adsorption performance of saturated PAC, making saturated PAC a hazardous waste problem that needs to be solved urgently.

[0003] Although stamp-charged coke ovens can improve the density of coal by layering and stamping, the microstructure of coke has more microcracks, and the reaction strength (CSR) is generally 3-5 percentage points lower than that of top-charged coke, limiting the application of stamp-charged coke in blast furnace ironmaking, and it is necessary to improve the strength by adding additives or optimizing the process.

[0004] Some technologies focus on the production of activated carbon from coke fines, but do not involve the regeneration and utilization of saturated PAC. Another part relies on raw activated carbon as an enhancer, which has high raw material cost and does not realize waste resource utilization, making it difficult to promote and apply. Therefore, it is necessary to propose a solution to this technical problem. SUMMARY

[0005] (I) Technical problems solved

[0006] In view of the deficiencies of the prior art, the present application provides a coke enhancer based on saturated activated carbon and its application in stamp-charged coke ovens.

[0007] (II) Technical solutions

[0008] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a preparation method of a coke enhancer based on saturated activated carbon, comprising the following steps:

[0009] Step 1: Saturated powdered activated carbon after adsorbing wastewater is treated with a mixed acid solution containing 3-8wt% HCl and 0.5-1.5wt% HF at 50-70℃ for 1-3h, and then washed with water to pH=6.0-7.0 to obtain PAC with ash content ≤4%;

[0010] Step 2: The PAC after deep ash removal is immersed in an aqueous solution containing 4-6wt% Ca(OH)2 and 1-3wt% aluminum dihydrogen phosphate for 20-40min, and a passivation layer is formed on the surface of the PAC after drying at 100-150℃;

[0011] Step 3: After the PAC is passivated, 6-8wt% coal tar and 2-4wt% starch are mixed uniformly, and then the mixture is pressed into particles with a particle size of 1.0-3.0mm under a pressure of 40-60MPa, and then the particles are pre-carbonized at 400-500°C in a nitrogen atmosphere for 0.5-1.5h to obtain the coke enhancer.

[0012] Further, the application improves that the adsorbate of the saturated PAC is tar, phenols and polycyclic aromatic hydrocarbons in coking wastewater, the COD adsorption capacity is ≥300mg / g, the original ash content is 15-25%, and the SiO2 content is ≥50%.

[0013] Further, the application improves that in the deep ash removal step, the stirring speed of the mixed acid solution is 200-500rpm, and the water washing is performed until the conductivity of the filtrate is ≤100μS / cm.

[0014] Further, the application improves that in the surface passivation step, the molar ratio of Ca(OH)2 to aluminum dihydrogen phosphate is 1:1 to 2:1, the drying time is 1-3h, and the thickness of the passivation layer is 50-100nm.

[0015] Further, the application improves that in the tar strengthening and granulating step, the shape of the pressed particles is spherical or spherical-like, the wear resistance index of the pre-carbonized particles is ≥90%, and the content of SiO2+Al2O3 in the ash is ≤55wt%.

[0016] The application also provides an application of the coke enhancer based on the saturated activated carbon in a stamp-charged coke oven.

[0017] Step 1: The enhancer is mixed into the coal at a proportion of 1-5% of the total weight of the coking coal.

[0018] Step 2: The layered laying process is adopted, and after laying coal with a thickness of 200-400mm, a layer of enhancer particles is uniformly sprayed.

[0019] Step 3: The bulk density of the coal cake after stamping is controlled to be 0.98-1.03t / m 3 , and the moisture content is ≤11%.

[0020] Further, the application improves that in the layered laying process, the spraying amount of the enhancer particles is controlled at 0.3-1.5% of the weight of each layer of coal, and the number of layers is 3-5.

[0021] Further, the application improves that in the coal cake regulation, the bulk density is controlled by adjusting the stamping pressure and the stamping time, and the moisture content is monitored in real time by using an infrared moisture meter.

[0022] Further, the present application improves that after the incorporation of the reinforcing agent, the post-reaction strength of the coke is increased by 3-5 percentage points, the reactivity is reduced by 4-6 percentage points, and the micro-crack density is reduced by ≥40%.

[0023] Further, the present application improves that the incorporation of the reinforcing agent is synchronized with the coal material, and the addition amount is controlled by a screw feeder to ensure that the uniformity error of the mixing with the coal material is ≤5%.

[0024] (III) Beneficial effects

[0025] Compared with the prior art, the present application provides a coke reinforcing agent based on saturated activated carbon and its application in stamp-charged coke ovens, which has the following beneficial effects:

[0026] The coke reinforcing agent based on saturated activated carbon and its application in stamp-charged coke ovens, the present application converts saturated PAC into a coke reinforcing agent, converts the adsorbed organic matter into a pore-forming agent through chemical descaling and surface modification, realizes the transformation of "waste pollution load" to "performance aid", and directly utilizes the adsorption properties of saturated PAC without complex regeneration equipment, thereby constructing a closed-loop system of "wastewater treatment, solid waste value-added, and coke upgrading", and fundamentally solving the disposal problem of saturated PAC.

[0027] After the incorporation of the reinforcing agent into the blended coal, a high-temperature stable phase is formed through the passivation layer to effectively inhibit the coke dissolution loss reaction; the modified PAC particles fill the interstitial gaps of the coal particles after thermal softening, improve the microstructure of the coke, reduce the porosity, and reduce the micro-cracks. The application results show that the thermal strength of the coke is significantly improved, the post-reaction strength is increased, the reactivity is reduced, the microstructure is densified, and the demand of blast furnace ironmaking for high-strength coke is met.

[0028] The layered material distribution process solves the problem of uneven distribution of additives in stamp-charged coke ovens, and the pre-carbonization treatment prevents the particles from cracking when entering the furnace, ensuring that the reinforcing agent plays the best role in the coking process. This technology not only reduces the disposal cost of saturated PAC, but also reduces the blending cost by replacing part of the expensive coal, while improving the coke grade to increase the sales value, and has environmental and economic benefits, providing a new path for the green and low-cost production of the coking industry. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application is a schematic diagram for the preparation of a coke reinforcing agent based on saturated activated carbon.

[0030] Figure 2 The present application is a schematic diagram for the application of a coke reinforcing agent based on saturated activated carbon in stamp-charged coke ovens.

[0031] Figure 3 The present application is a schematic diagram for the preparation of a coke reinforcing agent based on saturated activated carbon.

[0032] Figure 4 The application ratio schematic diagram of the saturated activated carbon-based coke enhancer in the stamping coke oven. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0034] Please refer to Figures 1-4 The present application is a saturated activated carbon-based coke enhancer preparation method, comprising the following steps:

[0035] Step 1: The saturated powdered activated carbon after adsorbing sewage is treated with a mixed acid solution containing 3-8wt% HCl and 0.5-1.5wt% HF at 50-70℃ for 1-3h, and then washed with water until pH=6.0-7.0 to obtain PAC with ash content≤4%;

[0036] Step 2: The PAC after deep ash removal is immersed in an aqueous solution containing 4-6wt% Ca(OH)2 and 1-3wt% aluminum dihydrogen phosphate for 20-40min, and then dried at 100-150℃ to form a passivation layer on the surface of PAC;

[0037] Step 3: The passivated PAC is uniformly mixed with 6-8wt% coal tar and 2-4wt% starch, and then pressed into particles with a particle size of 1.0-3.0mm under a pressure of 40-60MPa, and then pre-carbonized in a nitrogen atmosphere at 400-500℃ for 0.5-1.5h to obtain a coke enhancer.

[0038] In this scheme, the adsorbate of the saturated PAC is tar, phenols and polycyclic aromatic hydrocarbons in coking sewage, the COD adsorption capacity is≥300mg / g, the original ash content is 15-25%, and the SiO2 content is≥50%.

[0039] In this scheme, the stirring speed of the mixed acid solution in the deep ash removal step is 200-500rpm, and the water washing is until the filtrate conductivity is≤100μS / cm.

[0040] In this scheme, in the surface passivation step, the molar ratio of Ca(OH)2 to aluminum dihydrogen phosphate is 1:1 to 2:1, the drying time is 1-3h, and the passivation layer thickness is 50-100nm.

[0041] In the present scheme, the shape of the compressed granules in the tar reinforced granulation step is spherical or spheroidal, the wear resistance index of the pre-carbonized granules is ≥ 90%, and the SiO2+Al2O3 content in the ash is ≤ 55wt%.

[0042] The present application also provides a saturated activated carbon-based coke reinforcing agent for use in a stamp-charged coke oven, comprising the following processes:

[0043] Step 1: Mix the reinforcing agent into the coal blend at a ratio of 1-5% of the total weight of coking coal;

[0044] Step 2: Use a layered laying process, and after laying 200-400mm thick coal, uniformly spray a layer of reinforcing agent granules;

[0045] Step 3: Control the bulk density of the coal cake after stamping to be 0.98-1.03t / m 3 , and the moisture content is ≤ 11%.

[0046] In the present scheme, in the layered material distribution process, the spraying amount of reinforcing agent granules is controlled at 0.3-1.5% of the weight of each layer of coal, and the number of layers is 3-5.

[0047] In the present scheme, in the coal cake regulation, the bulk density is controlled by adjusting the stamping pressure and stamping time, and the moisture content is monitored in real time using an infrared moisture meter.

[0048] In the present scheme, after the reinforcing agent is mixed, the post-reaction strength of the coke is increased by 3-5 percentage points, the reactivity is reduced by 4-6 percentage points, and the micro-crack density is reduced by ≥ 40%.

[0049] In the present scheme, the reinforcing agent is mixed by being transported synchronously with the coal, and the addition amount is controlled by a screw feeder to ensure that the uniformity error of the mixture with the coal is ≤ 5%.

[0050] The organic matter (such as tar, polycyclic aromatic hydrocarbons) adsorbed by saturated PAC is decomposed by heat during the coking process to form gas-phase small molecules, which act as a pore former to adjust the pore structure of the coke and reduce the porosity by 15-20% (compared to the non-added group).

[0051] HF-HCl synergistic ash removal mechanism, HF targets to dissolve SiO2: through the reaction formula \text{SiO2+4HF→SiF4↑+2H2O}, selectively removes the quartz sand component in the ash, reducing the ash from the original 22% to ≤ 4%; HCl auxiliary role: dissolves metal oxides (such as Fe2O3, CaO), avoids the reaction with C at high temperature to generate low-melting-point compounds, and prevents the degradation of the hot strength of the coke.

[0052] Ca(OH)2and aluminum dihydrogen phosphate react to form Ca-P-Al composite oxides (such as CaAl2P2O8), which form a dense high-temperature-resistant phase at a coking temperature of 1100-1300°C, inhibiting the dissolution and loss reaction of CO on the coke (reaction rate reduced by 25-30%). The modified PAC softens thermally during coking (softening temperature 600-700°C), fills the micro-gaps between coal particles (SEM images show that the gap filling rate is ≥80%), making the coke microstructure more dense, and the micro-crack density reduced by ≥40%. Layered distribution: the modified PAC particles (1-3 mm) are layered with the coal material, and the uniform dispersion is promoted by the ramming pressure (150-200 MPa), solving the agglomeration problem caused by the hydrophilicity of PAC in the traditional mixing process; pre-carbonization treatment: pre-carbonization at 400-500°C in a nitrogen atmosphere, carbonizing part of the organic matter on the surface of PAC to form a "hard shell-soft core" structure, avoiding particle cracking caused by rapid heating (1000°C / min) after entering the furnace.

[0053] Example 1: Preparation of the reinforcing agent by saturating PAC modification:

[0054] Take the saturated PAC (ash content 22%, SiO2 content 51%, COD adsorption capacity 320 mg / g) after adsorbing coking wastewater; treat with 5% HCl + 1% HF mixed acid at 70°C for 2h, wash with water until pH = 6.5, and the ash content is reduced to 3.7%, and the SiO content is reduced from 51% to 12%; immerse the PAC in a 5% Ca(OH)2+2% aluminum dihydrogen phosphate solution for 30 min, and dry at 120°C for 2h to form a Ca-P-Al composite passivation layer (X-ray photoelectron spectroscopy confirms that the atomic ratio of Ca / P / Al is 1.2:1:0.8); mix with 7% coal tar + 3% starch, and press into 2mm particles under 50MPa, pre-carbonize in nitrogen at 450°C for 1h, and obtain a reinforcing agent with a wear resistance index of 92%, and the SiO+AlO3 content in the ash is 52wt%.

[0055] Example 2: Application effect in a stamp-charging coke oven:

[0056] In a 1 million ton / year stamp-charging coke oven, add 3% of the reinforcing agent by layering (spray 0.9% of the reinforcing agent per 300mm coal layer), control the coal cake bulk density to 1.00t / m 3 , and the moisture content to 9.5%; the coke CSR is increased from 62.1 to 65.9 (increased by 3.8 points), and the CRI is reduced from 29.3 to 24.5 (reduced by 4.8 points); microstructure analysis: the micro-crack density is reduced from 5.2 lines / mm to 3.0 lines / mm (reduced by 42%), and the porosity is reduced from 45% to 38%; the disposal cost of saturated PAC is changed from 1200 yuan / ton to a net profit of 300 yuan / ton (due to the replacement of part of the expensive lean coal), the coke selling price is increased by 80 yuan / ton, and 3800 tons of hazardous waste is reduced annually.

[0057] The following is a table of the technical effects of the present application:

[0058]

[0059] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely divergences of the principles and spirit of the application and that numerous modifications, changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the application as defined by the appended claims and their equivalents.

Claims

1. A method for preparing a coke enhancer based on saturated activated carbon, characterized in that: The following steps are involved: Step 1: The saturated powdered activated carbon after adsorption of sewage is treated with a mixed acid solution containing 3-8wt% HCl and 0.5-1.5wt% HF at 50-70°C for 1-3 hours under stirring, and then washed with water to a pH of 6.0-7.0 to obtain PAC with an ash content of ≤4%; Step 2: Immerse the deeply deashed PAC in an aqueous solution containing 4-6 wt% Ca(OH)2 and 1-3 wt% aluminum dihydrogen phosphate for 20-40 min, and form a passivation layer on the surface of the PAC after drying at 100-150°C; Step 3: The passivated PAC is evenly mixed with 6-8 wt% coal tar and 2-4 wt% starch, pressed into particles with a particle size of 1.0-3.0 mm at a pressure of 40-60 MPa, and then pre-carbonized in a nitrogen atmosphere at 400-500° C. for 0.5-1.5 h to obtain a coke enhancer.

2. The method for preparing a coke enhancer based on saturated activated carbon according to claim 1, characterized in that: The adsorbents of the saturated PAC are tar, phenols and polycyclic aromatic hydrocarbons in coking wastewater, its COD adsorption capacity is ≥300 mg / g, the original ash content is 15-25%, of which SiO2 accounts for ≥50%.

3. The method for preparing a coke enhancer based on saturated activated carbon according to claim 1, characterized in that: In the deep deashing step, the stirring speed of the mixed acid solution is 200-500 rpm, and the filtrate is washed with water until the conductivity of the filtrate is ≤100 μS / cm.

4. The method for preparing a coke enhancer based on saturated activated carbon according to claim 1, characterized in that: In the surface passivation step, the molar ratio of Ca(OH)2 to aluminum dihydrogen phosphate is 1:1 to 2:1, the drying time is 1-3 hours, and the thickness of the passivation layer is 50-100 nm.

5. The method for preparing a coke enhancer based on saturated activated carbon according to claim 1, characterized in that: In the tar-enhanced granulation step, the shape of the pressed particles is spherical or quasi-spherical, the wear resistance index of the pre-carbonized particles is ≥90%, and the SiO2+Al2O3 content in the ash is ≤55wt%.

6. Use of a coke enhancer based on saturated activated carbon according to any one of claims 1 to 5 in a stamping coke oven, characterized in that: Including the following processes: Step 1: Add the enhancer to the blended coal at a ratio of 1-5% of the total weight of the coking coal; Step 2: Use the layered laying process, and evenly spray a layer of reinforcing agent particles after laying 200-400mm thick coal material; Step 3: Control the bulk density of coal cakes after tamping to 0.98-1.03t / m 3 , moisture content ≤11%.

7. Use of a coke enhancer based on saturated activated carbon in a stamping coke oven according to claim 6, characterized in that: In the layered distribution process, the spraying amount of the reinforcing agent particles is controlled to be 0.3-1.5% of the weight of each layer of coal material, and the number of distribution layers is 3-5 layers.

8. The use of a coke enhancer based on saturated activated carbon in a stamping coke oven according to claim 6, characterized in that: In the briquette control, the bulk density is controlled by adjusting the tamping pressure and tamping time, and the moisture content is monitored in real time using an infrared moisture meter.

9. The use of a coke enhancer based on saturated activated carbon in a stamping coke oven according to claim 6, characterized in that: After the reinforcing agent is added, the post-reaction strength of the coke is increased by 3-5 percentage points, the reactivity is reduced by 4-6 percentage points, and the microcrack density is reduced by ≥40%.

10. Use of a coke enhancer based on saturated activated carbon in a stamping coke oven according to any one of claims 6 to 9, characterized in that: The reinforcing agent is added in a manner of being conveyed synchronously with the coal, and the amount of the reinforcing agent added is controlled by a screw feeder to ensure that the error of the uniformity of the mixing with the coal is ≤5%.

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