Composite calcium-based absorbent as well as preparation method and application thereof

Abstract

The invention belongs to the field of environmental protection, and particularly relates to a composite calcium-based absorbent as well as a preparation method and application thereof. The composite calcium-based absorbent provided by the invention is prepared by mixing and heating raw materials to react and then drying; the raw materials comprise the following components in parts by weight: 1000 parts of calcium oxide particles, 400-900 parts of water, 5-50 parts of a modifier and 20-100 parts of a non-carbon-based porous material. According to the calcium-based absorbent and the preparation method thereof, the component composition and the preparation process of the calcium-based absorbent are optimally designed, the adsorption and removal effect of the absorbent on various pollutants including dioxin in flue gas is remarkably improved, the production process of the absorbent is environmentally friendly, the cost is low, and the calcium-based absorbent has good environmental benefits and economic benefits.

Description

Technical Field

[0001] The invention belongs to the field of environmental protection, and in particular relates to a composite calcium-based absorbent and a preparation method and application thereof. Background Art

[0002] Steel smelting, heating, waste incineration and chemical production processes will emit a large amount of pollutants, including particulate matter, acidic gases and dioxins, etc. There are relatively mature emission regulations for particulate matter and acidic gases, but for dioxin emission standards, only a few related fields such as garbage incineration and medical waste incineration have issued emission standards.

[0003] At present, the main control technology for the high concentration of dioxin flue gas in the incineration industry in my country is semi-dry or dry desulfurization (slaked lime) combined with activated carbon injection or selective catalytic reduction technology. The preparation of activated carbon uses coal tar and asphalt as binders, which inevitably produces pollutants such as hydrocarbons and benzene organic matter during the high-temperature treatment processes of carbonization and activation. However, precious metal catalysts are expensive, require large investments, and have short replacement cycles, which increase the environmental protection costs of enterprises. Therefore, how to achieve the treatment of dioxins in flue gas at a lower cost and in an environmentally friendly way is an urgent problem to be solved in this field. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a composite calcium-based absorbent and a preparation method and application thereof. The composite calcium-based absorbent provided by the present invention can efficiently adsorb and remove various pollutants including dioxins in flue gas, and its production process is relatively environmentally friendly and low-cost, with good environmental and economic benefits.

[0005] The present invention provides a composite calcium-based absorbent, which is prepared by mixing raw materials, heating and reacting, and then drying; the raw materials include the following components in parts by weight:

[0006]

[0007]

[0008] The particle size of the calcium oxide particles is ≥100 mesh;

[0009] The modifier includes a first modifier and a second modifier, the first modifier is one or more of methanol, ethanol, methane and pentane, the second modifier is one or more of ethylene glycol, diethylene glycol, propylene glycol, glycerol, triethanolamine, glucose, sodium citrate, sucrose, sodium carboxymethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, sodium lignin sulfonate and calcium lignin sulfonate, and the mass ratio of the first modifier to the second modifier is 1: (1 to 2).

[0010] Preferably, the non-carbon-based porous material is magnesium silicate and / or microporous active silicon.

[0011] Preferably, the non-carbon-based porous material has a pore size of 2 to 100 nm and a pore volume of 0.2 to 0.5 cm 3 / g, specific surface area is 100~1100m 2 / g.

[0012] Preferably, the particle size of the non-carbon-based porous material is ≥100 mesh.

[0013] The present invention provides a method for preparing the composite calcium-based absorbent described in the above technical solution, comprising the following steps:

[0014] The calcium oxide particles, the non-carbon-based porous material, the modifier and water are mixed and heated to react to obtain an emulsion;

[0015] The emulsion is dried to obtain a composite calcium-based absorbent.

[0016] Preferably, the temperature of the mixed heating reaction is 100-150°C.

[0017] Preferably, the mixing speed of the mixed heating reaction is ≥350r / min.

[0018] Preferably, the mixing and heating reaction time is 20 to 60 minutes.

[0019] Preferably, the drying temperature is 120-150°C.

[0020] The present invention provides a flue gas adsorption purification method, comprising the following steps:

[0021] The pollutants in the flue gas are adsorbed and purified using the composite calcium-based absorbent described in the above technical solution or the composite calcium-based absorbent prepared by the preparation method described in the above technical solution.

[0022] Compared with the prior art, the present invention provides a composite calcium-based absorbent and its preparation method and application. The composite calcium-based absorbent provided by the present invention is prepared by mixing raw materials, heating and reacting, and then drying; in parts by weight, the raw materials include the following components: 1000 parts of calcium oxide particles, 400-900 parts of water, 5-50 parts of modifiers, and 20-100 parts of non-carbon-based porous materials; the particle size of the calcium oxide particles is ≥100 mesh; the modifier includes a first modifier and a second modifier, the first modifier is one or more of methanol, ethanol, methane and pentane, the second modifier is one or more of ethylene glycol, diethylene glycol, propylene glycol, glycerol, triethanolamine, glucose, sodium citrate, sucrose, sodium carboxymethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, sodium lignin sulfonate and calcium lignin sulfonate, and the mass ratio of the first modifier to the second modifier is 1: (1-2). The present invention significantly improves the adsorption and removal effect of the absorbent on various pollutants in flue gas, including dioxins, by optimizing the component composition and preparation process of the calcium-based absorbent. The production process of the absorbent is more environmentally friendly and low-cost, and has both good environmental and economic benefits. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention provides a composite calcium-based absorbent, which is prepared by mixing raw materials, heating and reacting, and then drying; the raw materials include the following components in parts by weight:

[0025]

[0026] In the composite calcium-based absorbent provided by the present invention, the particle size of the calcium oxide particles in the raw material is ≥100 meshes.

[0027] In the composite calcium-based absorbent provided by the present invention, the water content in the raw material can specifically be 400 parts by weight, 450 parts by weight, 500 parts by weight, 550 parts by weight, 600 parts by weight, 650 parts by weight, 700 parts by weight, 750 parts by weight, 800 parts by weight, 850 parts by weight or 900 parts by weight.

[0028] In the composite calcium-based absorbent provided by the present invention, the modifier in the raw material includes a first modifier and a second modifier; wherein the first modifier is one or more of methanol, ethanol, methane and pentane; the second modifier is one or more of ethylene glycol, diethylene glycol, propylene glycol, glycerol, triethanolamine, glucose, sodium citrate, sucrose, sodium carboxymethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, sodium lignin sulfonate and calcium lignin sulfonate; the mass ratio of the first modifier to the second modifier is preferably 1: (1-2), specifically 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.

[0029] In the composite calcium-based absorbent provided by the present invention, the content of the modifier in the raw material can specifically be 5 parts by weight, 10 parts by weight, 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight or 50 parts by weight.

[0030] In the composite calcium-based absorbent provided by the present invention, the non-carbon-based porous material in the raw material is preferably magnesium silicate and / or microporous active silicon, and the mass ratio of the magnesium silicate to the microporous active silicon is preferably 1:(1-5), specifically 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5; the pore size of the non-carbon-based porous material is preferably 2-100 nm, specifically 2 nm, 3 nm, 4 nm, 4.9 nm, 5 nm, 5.5 nm, 6 nm, 7 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm; the pore volume of the non-carbon-based porous material is preferably 0.2-0.5 cm 3 / g, specifically 0.2cm 3 / g, 0.24cm 3 / g, 0.25cm 3 / g, 0.3cm 3 / g, 0.35cm 3 / g, 0.4cm 3 / g, 0.45cm 3 / g or 0.5cm 3 / g; the specific surface area of ​​the non-carbon-based porous material is preferably 100 to 1100 m 2 / g, specifically 100m 2 / g, 200m 2 / g, 267m 2 / g、300m 2 / g、353m 2 / g, 400m 2 / g、500m 2 / g、600m 2 / g、700m 2 / g、800m 2 / g、900m 2 / g、1000m 2 / g or 1100m 2 / g; the particle size of the non-carbon-based porous material is preferably ≥100 mesh.

[0031] In the composite calcium-based absorbent provided by the present invention, the content of the non-carbon-based porous material in the raw material can specifically be 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight or 100 parts by weight.

[0032] In the composite calcium-based absorbent provided by the present invention, the specific surface area of ​​the composite calcium-based absorbent is preferably ≥40m 2 / g, the pore volume is preferably ≥0.2m 3 / g.

[0033] The present invention also provides a method for preparing the composite calcium-based absorbent described in the above technical solution, comprising the following steps:

[0034] The calcium oxide particles, the non-carbon-based porous material, the modifier and water are mixed and heated to react to obtain an emulsion;

[0035] The emulsion is dried to obtain a composite calcium-based absorbent.

[0036] In the preparation method provided by the present invention, the calcium oxide particles and the non-carbon-based porous material are preferably ground to a desired particle size range before being mixed.

[0037] In the preparation method provided by the present invention, the temperature of the mixed heating reaction is preferably 100-150°C, specifically 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C; the mixing speed of the mixed heating reaction is preferably ≥350r / min, more preferably 350-500r / min, specifically 350r / min, 400r / min, 450r / min or 500r / min; the time of the mixed heating reaction is preferably 20-60min, specifically 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min or 60min.

[0038] In the preparation method provided by the present invention, the drying temperature is preferably 120-150°C, specifically 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C; the drying time is not particularly limited, and it is preferably dried until the moisture content of the product is ≤3%.

[0039] The present invention also provides a flue gas adsorption purification method, comprising the following steps:

[0040] The pollutants in the flue gas are adsorbed and purified using the composite calcium-based absorbent described in the above technical solution or the composite calcium-based absorbent prepared by the preparation method described in the above technical solution.

[0041] In the adsorption purification method provided by the present invention, the desulfurization efficiency of the composite calcium-based absorbent is preferably ≥99%, and the dioxin removal efficiency is preferably ≥90%.

[0042] The technical solution provided by the present invention optimizes the composition and preparation process of the calcium-based absorbent, significantly improving the adsorption and removal effect of the absorbent on various pollutants in flue gas, including dioxins, and the production process of the absorbent is relatively environmentally friendly and low-cost, with good environmental and economic benefits. More specifically, the technical solution of the present invention has at least the following advantages:

[0043] (1) High efficiency in removing acidic gases, saving the amount of absorbent, and adapting to high-sulfur working conditions: The main body of the absorbent of the present invention is calcium hydroxide absorbent, which is modified by a modifier and the water-cement ratio and reaction conditions are optimized to achieve the effects of large specific surface area, high pore volume and high purity. It can cope with high-sulfur and high-humidity working conditions, has good ability to remove acidic gases, and saves the amount of absorbent.

[0044] (2) Synergistic removal of multiple pollutants and reduction of corporate environmental protection costs: Adding non-carbon-based porous materials to the absorbent raw materials can obtain the ability to remove dioxins, which is beneficial for the company to meet environmental protection standards and saves the investment in introducing new equipment.

[0045] (3) The absorbent is mixed evenly and the adsorption capacity is stable: Since the particle size and density of slaked lime and non-carbon-based porous materials are different, direct mixing will inevitably cause uneven phenomena such as stratification of the two materials due to different grading coefficients; therefore, the present invention preferably grinds the non-carbon-based porous material and slaked lime to approximately the same particle size before performing subsequent preparation steps, so that the different materials of the obtained product are evenly mixed, and the ability to remove acidic gases and dioxins is stable and does not fluctuate.

[0046] For the purpose of greater clarity, the invention is described in detail through the following examples.

[0047] Example 1

[0048] Step 1: Add 500g of magnesium silicate adsorbent (pore size: 4.9nm, specific surface area: 267m 2 / g, pore volume: 0.24cm 3 / g), and then ground by Raymond mill to a mesh size of ≥100 to form ash.

[0049] Step 2: Add a modifier to 6 kg of digestion water, the modifier is a mixture of 20 g of methane and 30 g of triethanolamine; mix the above ash with the digestion water for digestion treatment to obtain a calcium-based absorbent intermediate product; the temperature during the digestion process is controlled at 100-150°C, the digestion time is 30 minutes, and the stirring shaft speed is 350 r / min.

[0050] Step 3: Drying the calcium-based absorbent intermediate product at a temperature of 120-150° C. to a moisture content of ≤3% to obtain a composite calcium-based absorbent having the ability to synergistically remove multiple pollutants.

[0051] Example 2

[0052] The steps and methods in Example 1 were repeated, except that the non-carbon-based porous adsorbent material was 200 g of magnesium silicate adsorbent (pore size: 4.9 nm, specific surface area: 267 m 2 / g, pore volume: 0.24cm 3 / g) and 400g of microporous active silicon (pore size: 5.5nm, specific surface area: 353m 2 / g, pore volume: 0.35cm 3 / g), and the modifier added to the digestion water was a mixture of 20g methanol and 30g ethylene glycol.

[0053] Comparative Example 1

[0054] The steps and methods in Example 1 were repeated, but no non-carbon-based porous material was added and no modifier was added to the digested water.

[0055] Comparative Example 2

[0056] The steps and methods in Example 1 were repeated, but without adding the non-carbon-based porous material, a mixture of 20 g of methane and 30 g of triethanolamine was added to 6 kg of digestion water.

[0057] Performance Evaluation

[0058] The composite calcium-based absorbent obtained in the examples and comparative examples was tested for its sulfur dioxide and dioxin removal capacity using a fixed bed evaluation system. Trichlorobenzene was used to simulate the dioxin desorption effect. The composition of the simulated flue gas was: SO2 (330 vppm), NO (330 vppm), O2 (8 vol.%), H2O (10 vol.%), and carrier gas N2. The total gas volume of the mixed gas was about 0.6 mL / min, and the concentration of trichlorobenzene vapor was 20 μg / Nm 3 The test method for O2, NO, SO2, and H2O in flue gas is FodischUVA17m ultraviolet differential flue gas analyzer. The test method for trichlorobenzene in flue gas is to pass isooctane absorption liquid into the flue gas and then measure the concentration of trichlorobenzene absorbed in it by gas chromatograph. The physical properties of the composite calcium-based absorbent and the removal efficiency of different pollutants are recorded as follows:

[0059] Table 1 Physical properties of composite calcium-based absorbent and removal efficiency of different pollutants

[0060]

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A composite calcium-based absorbent, characterized in that: The raw materials are mixed, heated and reacted, and then dried to prepare the product; the raw materials include the following components by weight: The particle size of the calcium oxide particles is ≥100 mesh; The modifier includes a first modifier and a second modifier, the first modifier is one or more of methanol, ethanol, methane and pentane, the second modifier is one or more of ethylene glycol, diethylene glycol, propylene glycol, glycerol, triethanolamine, glucose, sodium citrate, sucrose, sodium carboxymethyl cellulose, methyl cellulose, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, sodium lignin sulfonate and calcium lignin sulfonate, and the mass ratio of the first modifier to the second modifier is 1: (1 to 2).

2. The composite calcium-based absorbent according to claim 1, characterized in that: The non-carbon-based porous material is magnesium silicate and / or microporous active silicon.

3. The composite calcium-based absorbent according to claim 1, characterized in that: The non-carbon-based porous material has a pore size of 2 to 100 nm and a pore volume of 0.2 to 0.5 cm 3 / g, specific surface area is 100~1100m 2 / g.

4. The composite calcium-based absorbent according to claim 1, characterized in that: The particle size of the non-carbon-based porous material is ≥100 mesh.

5. A method for preparing the composite calcium-based absorbent according to any one of claims 1 to 4, characterized in that: The following steps are involved: The calcium oxide particles, the non-carbon-based porous material, the modifier and water are mixed and heated to react to obtain an emulsion; The emulsion is dried to obtain a composite calcium-based absorbent.

6. The preparation method according to claim 5, characterized in that: The temperature of the mixed heating reaction is 100-150°C.

7. The preparation method according to claim 5, characterized in that: The mixing speed of the mixed heating reaction is ≥350r / min.

8. The preparation method according to claim 5, characterized in that: The mixing and heating reaction time is 20 to 60 minutes.

9. The preparation method according to claim 5, characterized in that: The drying temperature is 120-150°C.

10. A flue gas adsorption purification method, characterized in that: The following steps are involved: The pollutants in the flue gas are adsorbed and purified using the composite calcium-based absorbent described in any one of claims 1 to 4 or the composite calcium-based absorbent prepared by the preparation method described in any one of claims 5 to 9.

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