A method for preparing a ceramic membrane support body using biomass power plant ash and a ceramic membrane support body

Abstract

The application relates to a method for preparing a ceramic membrane support body by using biomass power plant ash and the ceramic membrane support body, and belongs to the field of comprehensive utilization of solid waste. Biomass power plant ash is dried, screened and obtained in the form of ash with a particle size of 0.1 mm or below, a liquid binder composed of water, polyvinyl alcohol, glycerol and anhydrous ethanol is prepared, then the screened ash and the liquid binder are mixed in proportion, uniformly ground and pressed into a shape, dried, demolded and sintered at high temperature to obtain the ceramic membrane support body. The main function of the binder is to granulate and enhance the powder fluidity, and due to the viscosity, the pressed sheet is more complete and less likely to be layered and damaged. The ceramic membrane support body prepared by the application can meet the industry requirements in mechanical strength and water permeation flux, can be applied in the field of wastewater treatment, can achieve the purpose of treating waste with waste, and has good economic and social benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of comprehensive utilization of solid waste, and particularly relates to a method for preparing a ceramic membrane support body by using biomass power plant ash and the ceramic membrane support body. BACKGROUND

[0002] With the increasing reduction of fossil fuels, the energy crisis is further intensified, which promotes the unprecedented development of renewable energy. Biomass power generation technology has become an important power generation and heating method in some countries, and has also been vigorously promoted in China. However, a large amount of ash is generated after the combustion of biomass raw materials, which will become a new source of pollution and cause great waste if there is no effective treatment method.

[0003] The ceramic membrane is an inorganic ceramic filtration material, which has the characteristics of high thermal stability, high mechanical strength, resistance to chemical and biological erosion, easy regeneration, long service life, controllable separation limit and selectivity compared with organic membranes, and has been applied in the fields of environmental protection, energy, food, chemical industry, medicine and the like.

[0004] At present, the raw material for preparing the ceramic membrane support body is generally ceramic powder, such as alumina, zirconia and mullite powder, etc., and the preparation cost is much higher than that of organic membranes, which limits the popularization and application of ceramic membranes. The present application uses biomass power plant ash as raw material, adds a binder, and prepares an inorganic ceramic membrane support body through the processes of mixing, pressing, drying, demolding and sintering, which significantly reduces the production cost of ceramic membranes. SUMMARY

[0005] The present application aims to provide a method for preparing a ceramic membrane support body by using biomass power plant ash and the ceramic membrane support body. The present application utilizes the solid waste ash generated by biomass power plants, replaces the original high-cost raw materials, and prepares a ceramic membrane support body, which can be applied in the field of wastewater treatment, can filter out solid particles with a particle size of 10 microns or more, and can also make various membrane layers (such as zirconia, titanium oxide and silicon oxide, etc.) adhere and grow on the surface of the support body for different target pollutants, so as to achieve the purpose of waste treatment.

[0006] The biomass power plant ash is dried and then sieved, and then a liquid binder is prepared. The sieved ash and the liquid binder are mixed in proportion, ground uniformly, and then pressed into a shape. After drying, demolding and high-temperature sintering, a ceramic membrane support body is obtained. The prepared ceramic membrane support body can meet the industry requirements in terms of mechanical strength and water permeation flux, and has good economic and social benefits.

[0007] The method for preparing a ceramic membrane support body by using biomass power plant ash comprises the following steps:

[0008] (1) using biomass power plant waste ash as raw material, drying the moisture at 100-120℃ for 12-24 hours, and sieving to obtain ash with particle size below 0.1mm;

[0009] (2) mixing water, polyvinyl alcohol, glycerol and anhydrous ethanol under water bath condition at 85-95℃, stirring until clear to obtain a colorless transparent viscous liquid binder; the volume content of water is 88-92%, the volume content of polyvinyl alcohol is 3-7%, the volume content of glycerol is 2-4%, and the volume content of anhydrous ethanol is 1-3% based on 100%;

[0010] (3) adding the liquid binder obtained in step (2) to the ash obtained in step (1), and grinding or ball milling to mix uniformly;

[0011] (4) loading the mixture obtained in step (3) into a tablet press mold to form a thin sheet with a thickness of 2-3mm under a certain pressure, and demolding to obtain a green body of the support;

[0012] (5) sintering the green body of the support obtained in step (4) at 1100℃ to obtain the sheet-shaped ceramic membrane support.

[0013] The mass ratio of the ash to the liquid binder is 8-12:1, the tablet pressing pressure is 10-30MPa, the heating rate during sintering is 4-6℃ / min, and the sintering time is 1.5-3.0h.

[0014] The most preferred process conditions are: the particle size of the ash is 0.05mm, the tablet pressing pressure is 20MPa, and the sintering temperature is 1100℃.

[0015] A ceramic membrane support is prepared by the above method.

[0016] The biomass power plant ash mainly contains SiO2, and the mechanical strength of the product can be greatly increased after mixing with the liquid binder and sintering. In addition, the micropores left after sintering of the binder and the stacking pores between the ash particles together form water flow channels, increasing the water flux of the product.

[0017] The present application has the advantages of low cost, simple process, safety and environmental protection, etc. The ceramic membrane support obtained can achieve the performance of similar products on the market, and various membrane layers (such as zirconia, titanium oxide and silicon oxide, etc.) can be attached and grown on the surface of the support through coating technology. The present application realizes the comprehensive utilization of biomass ash, reduces the disposal cost of biomass power plant waste, promotes the sustainable development of the biomass power generation industry, and has good ecological and economic benefits. Attached Figure Description

[0018] Figure 1 The XRD patterns of the ceramic film supports prepared in Examples 1, 2, and 3 are shown below.

[0019] Figure 2 SEM image of the surface of the ceramic film support obtained in Example 1;

[0020] Figure 3 SEM image of the cross-section of the ceramic membrane support obtained in Example 1;

[0021] Table 1: Performance data of products from each embodiment

[0022]

[0023]

[0024] Table 1 shows that Example 1 maintains high pure water throughput while ensuring flexural strength; Example 2 failed to form a good sintered bond and was easily damaged under water flow; Example 3 showed a molten surface, making it difficult for water to pass through; Examples 5-8 had poor flexural strength. In summary, Example 1 is the best example.

[0025] from Figure 1 The analysis reveals that the main component of the original biomass power plant ash is crystalline SiO2, indicating that silicon in the biomass forms crystalline SiO2 at the high temperatures inside the biomass power plant boiler. The diffraction peak intensity gradually increases with increasing sintering temperature. However, when the sintering temperature reaches 1200℃, the diffraction peak intensity decreases sharply, possibly due to the melting of the crystalline SiO2 caused by the excessively high temperature. The molten state on the surface of the sintered sample further confirms that 1200℃ is the critical temperature at which the sample begins to melt.

[0026] from Figure 2 , Figure 3 As can be seen from this, the sample obtained in Example 1 not only formed a sintered connection, which improved the bending strength of the sample, but also formed a pore structure, which ensured that the sample had a good pure water flux. Detailed Implementation

[0027] Example 1

[0028] (1) Heat the biomass power plant ash residue at 100℃ for 12 hours to dry the moisture, and then sieve it using a 300-mesh standard sieve. Take the biomass ash residue with a particle size ≤0.05mm for later use.

[0029] (2) Under the condition of 90°C water bath, add 90% water, 5% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol in sequence, stir until clear, and obtain liquid binder.

[0030] (3) Take 5 g of the sieved biomass ash in step (1), add 0.5 g of the liquid binder prepared in step (2), and grind for 15 min to mix them uniformly.

[0031] (4) Put the mixture obtained in step (3) into a tablet press mold, and press-forming under a pressure of 20 MPa using a tablet press, to obtain a green body of the support after demolding.

[0032] (5) Put the green body obtained in step (4) into a high-temperature furnace, and heat at a rate of 5 ℃ / min to 1100 ℃, and keep the temperature for 2 h, to obtain a ceramic membrane support after natural cooling to room temperature.

[0033] This example is the best example.

[0034] Example 2

[0035] (1) Dry the moisture of the biomass power plant ash by heating at 100 ℃ for 12 h, and sieve using a standard sieve of 300 meshes, to obtain the biomass ash with a particle size of ≤0.05 mm for standby use.

[0036] (2) Under the condition of a water bath at 90 ℃, add (by volume fraction) 90% water, 5% polyvinyl alcohol, 3% glycerol, and 2% anhydrous ethanol in sequence, and stir until clear, to obtain a liquid binder.

[0037] (3) Take 5 g of the sieved biomass ash in step 1, add 0.5 g of the liquid binder prepared in step 2, and grind for 15 min to mix them uniformly.

[0038] (4) Put the mixture obtained in step 3 into a tablet press mold, and press-forming under a pressure of 20 MPa using a tablet press, to obtain a green body of the support after demolding.

[0039] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat at a rate of 5 ℃ / min to 1000 ℃, and keep the temperature for 2 h, to obtain a ceramic membrane support after natural cooling to room temperature.

[0040] Compared with Example 1, the sintering temperature is changed to 1000 ℃.

[0041] Example 3

[0042] (1) Dry the moisture of the biomass power plant ash by heating at 100 ℃ for 12 h, and sieve using a standard sieve of 300 meshes, to obtain the biomass ash with a particle size of ≤0.05 mm for standby use.

[0043] (2) Under the condition of a water bath at 90 ℃, add (by volume fraction) 90% water, 5% polyvinyl alcohol, 3% glycerol, and 2% anhydrous ethanol in sequence, and stir until clear, to obtain a liquid binder.

[0044] (3) Take 5 g of the screened biomass ash in step 1, add 0.5 g of the liquid binder prepared in step 2, and grind for 15 min to make them uniformly mixed.

[0045] (4) Put the mixture obtained in step 3 into a tablet press mold, and use a tablet press to press-form under a pressure of 20 MPa to obtain a green body of the support.

[0046] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat it to 1200℃ at a rate of 5℃ / min, keep it at this temperature for 2 h, and then naturally cool it to room temperature to obtain a ceramic membrane support.

[0047] Compared with Example 1, the sintering temperature is changed to 1200℃.

[0048] Example 4

[0049] (1) Dry the biomass power plant ash at 100℃ for 12 h, screen it using a standard sieve of 150 mesh, and take the biomass ash with a particle size of 0.05-0.1 mm for standby use.

[0050] (2) Under the condition of a water bath at 90℃, add (by volume fraction) 90% water, 5% polyvinyl alcohol, 3% glycerol, and 2% anhydrous ethanol in sequence, stir until clear, and obtain a liquid binder.

[0051] (3) Take 5 g of the screened biomass ash in step 1, add 0.5 g of the liquid binder prepared in step 2, and grind for 15 min to make them uniformly mixed.

[0052] (4) Put the mixture obtained in step 3 into a tablet press mold, and use a tablet press to press-form under a pressure of 20 MPa to obtain a green body of the support.

[0053] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat it to 1100℃ at a rate of 5℃ / min, keep it at this temperature for 2 h, and then naturally cool it to room temperature to obtain a ceramic membrane support.

[0054] Compared with Example 1, the screening particle size is changed to 0.05-0.1 mm. The pure water flux increases, but the bending strength decreases, indicating that there is a certain trade-off relationship between the water flux and the bending strength with the increase of the particle size, and the bending strength of the support needs to be preferentially ensured.

[0055] Example 5

[0056] (1) Dry the biomass power plant ash at 100℃ for 12 h, screen it using a standard sieve of 300 mesh, and take the biomass ash with a particle size of ≤0.05 mm for standby use.

[0057] (2) Under the condition of 90℃ water bath, add (volume fraction) 90% water, 5% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol in turn, stir until clear, and obtain a liquid binder.

[0058] (3) Take 5g of the screened biomass ash in step 1, add 0.5g of the liquid binder prepared in step 2, and grind for 15min to make them uniformly mixed.

[0059] (4) Put the mixture obtained in step 3 into a tabletting die, and use a tablet press to press and form under the pressure of 10MPa, and obtain a support green body after demolding.

[0060] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat to 1100℃ at a rate of 5℃ / min, keep for 2h, and obtain a ceramic membrane support after natural cooling to room temperature.

[0061] Compared with Example 1, the tabletting pressure is changed to 10MPa.

[0062] Example 6

[0063] (1) Dry the moisture of the biomass power plant ash by heating at 100℃ for 12h, and screen using a standard sieve of 300 meshes, and take the biomass ash with particle size ≤0.05mm for standby use.

[0064] (2) Under the condition of 90℃ water bath, add (volume fraction) 90% water, 5% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol in turn, stir until clear, and obtain a liquid binder.

[0065] (3) Take 5g of the screened biomass ash in step 1, add 0.5g of the liquid binder prepared in step 2, and grind for 15min to make them uniformly mixed.

[0066] (4) Put the mixture obtained in step 3 into a tabletting die, and use a tablet press to press and form under the pressure of 30MPa, and obtain a support green body after demolding.

[0067] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat to 1100℃ at a rate of 5℃ / min, keep for 2h, and obtain a ceramic membrane support after natural cooling to room temperature.

[0068] Compared with Example 1, the tabletting pressure is changed to 30MPa.

[0069] Example 7

[0070] (1) Dry the moisture of the biomass power plant ash by heating at 100℃ for 12h, and screen using a standard sieve of 300 meshes, and take the biomass ash with particle size ≤0.05mm for standby use.

[0071] (2) In the condition of 90℃ water bath, add (volume fraction) 92% water, 3% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol in turn, stir until clear, and obtain the liquid binder.

[0072] (3) Take 5g of the screened biomass ash in step 1, add 0.5g of the liquid binder prepared in step 2, and grind for 15min to make them uniformly mixed.

[0073] (4) Put the mixture obtained in step 3 into a tablet press mold, and use a tablet press to press and form under the pressure of 20MPa, and obtain the green body of the support after demolding.

[0074] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat to 1100℃ at a rate of 5℃ / min, keep for 2h, and obtain the ceramic membrane support after natural cooling to room temperature.

[0075] Compared with Example 1, the binder composition (volume fraction) is changed to 92% water, 3% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol.

[0076] Example 8

[0077] (1) Dry the moisture of the biomass power plant ash by heating at 100℃ for 12h, and screen using a standard sieve of 300 meshes, and take the biomass ash with particle size ≤0.05mm for standby.

[0078] (2) In the condition of 90℃ water bath, add (volume fraction) 88% water, 7% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol in turn, stir until clear, and obtain the liquid binder.

[0079] (3) Take 5g of the screened biomass ash in step 1, add 0.5g of the liquid binder prepared in step 2, and grind for 15min to make them uniformly mixed.

[0080] (4) Put the mixture obtained in step 3 into a tablet press mold, and use a tablet press to press and form under the pressure of 20MPa, and obtain the green body of the support after demolding.

[0081] (5) Put the green body obtained in step 4 into a high-temperature furnace, and heat to 1100℃ at a rate of 5℃ / min, keep for 2h, and obtain the ceramic membrane support after natural cooling to room temperature.

[0082] Compared with Example 1, the binder composition (volume fraction) is changed to 88% water, 7% polyvinyl alcohol, 3% glycerol and 2% anhydrous ethanol.

Claims

1. A method for preparing a ceramic membrane support body using biomass power plant ash, comprising the following steps: (1) using biomass power plant waste ash as raw material, drying the moisture at 100-120℃ for 12-24 hours, and sieving to obtain ash with a particle size of less than 0.1 mm; (2) mixing water, polyvinyl alcohol, glycerol and anhydrous ethanol, stirring until clear under water bath conditions at 85-95℃ to obtain a colorless transparent viscous liquid binder; the volume content of water is 88-92%, the volume content of polyvinyl alcohol is 3-7%, the volume content of glycerol is 2-4%, and the volume content of anhydrous ethanol is 1-3% based on 100%; (3) adding the liquid binder obtained in step (2) to the ash obtained in step (1), and grinding or ball milling to mix uniformly; the mass ratio of ash to liquid binder is 8-12:1; (4) loading the mixture obtained in step (3) into a tablet press mold, and pressing to form a sheet with a thickness of 2-3 mm under a certain pressure to obtain a support body green body; the tablet pressing pressure is 10-30 MPa, the heating rate during sintering is 4-6℃ / min, and the sintering time is 1.5-3.0 h; and (5) sintering the support body green body obtained in step (4) at 1100℃ to obtain a sheet-shaped ceramic membrane support body. The ash particle size is 0.05 mm, and the tablet pressing pressure is 20 MPa. The sheet-shaped ceramic membrane support body is prepared by the method of any one of claims 1 or 2. ​ ​ ​ 2. The method for preparing a ceramic membrane support using biomass power plant ash according to claim 1, characterized by: ​ 3. A ceramic membrane support, characterized by: ​

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