Method for separating gas-liquid/liquid mixtures through pervaporation and vapor permeation by ion-exchange SAPO-34 molecular sieve membrane
A technology of SAPO-34 and gas-liquid mixture, applied in separation methods, separation/purification of hydroxyl compounds, semi-permeable membrane separation, etc., can solve the problems of molecular sieve membrane selectivity to be improved, slow speed, etc., and achieve great economic value, The effect of low energy consumption and high separation coefficient
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Embodiment 1
[0058] Example 1 Separation of methanol / dimethyl carbonate by potassium ion exchange SAPO-34 molecular sieve membrane obtained by simultaneous ion exchange and template removal
[0059] Step 1: Add 2.46g of deionized water to 31.13g of tetraethylammonium hydroxide solution (TEAOH, 35wt%), then weigh 7.56g of aluminum isopropoxide and add it to the aforementioned solution, and stir at room temperature for 2-3 hours; 1.665g silica sol (40wt%) was added dropwise and stirred for 1 hour; finally 8.53g phosphoric acid solution (H 3 PO 4 , 85wt%), stirred overnight (such as stirring for 12 hours). Using microwave heating, crystallize at 180°C for 7 hours. After the product is taken out, it is centrifuged, washed, and dried to obtain SAPO-34 molecular sieve seed crystals.
[0060] Among them, the SEM image and XRD image of the seed crystal are as follows Figure 1-2 Shown. It can be seen from the SEM image that the size of the seed crystal is about 300 nm×300 nm×100 nm, and the XRD patt...
Embodiment 2120
[0071] Example: Separation of methanol / dimethyl carbonate by ion exchange SAPO-34 molecular sieve membrane at 2120°C
[0072] The difference from Example 1 is that the feed concentration MeOH / DMC in step 5 is 90 / 10 (mass ratio), the separation operation temperature is 120° C., and the permeate side pressure is 0.3 MPa. The remaining steps are the same as in Example 1.
[0073] Table 2 MeOH / DMC vapor phase permeation separation test results of Example 2
[0074]
[0075] It can be seen from Table 2 that when the feed concentration MeOH / DMC is 90 / 10 and the operating temperature is 120°C, the methanol selectivity of the ion-exchanged SAPO-34 molecular sieve membrane is greater than 4000, and the flux is greatly improved compared with 70°C. The increase in flux is due to the increase in the feed pressure leading to an increase in the driving force of methanol mass transfer. It can be seen that the SAPO-34 molecular sieve membrane after ion exchange has a very high methanol-dimethyl ca...
Embodiment 3
[0076] Example 3 Separation of methanol / dimethyl carbonate by SAPO-34 molecular sieve membrane obtained by ion exchange of molten sodium after removing the template
[0077] The difference from Example 1 is that in step 4, the molecular sieve membrane tube obtained in step 3 is vacuum roasted at 400°C for 4 hours to remove the template, and after cooling to room temperature, it is placed in a 1 wt% sodium nitrate aqueous solution. Immerse for 3 minutes, take it out to dry at room temperature, and calcinate at 310°C for 8 hours for ion exchange to obtain sodium ion exchange molecular sieve membrane. In step 5, the feed concentration MeOH / DMC is 90 / 10 (mass ratio), the separation operation temperature is 120° C., and the permeate side pressure is 0.3 MPa. The remaining steps are the same as in Example 1.
[0078] Table 3 MeOH / DMC vapor phase permeation separation test results of Example 3
[0079]
[0080] It can be seen from Table 3 that when the feed concentration MeOH / DMC is 90 / 10...
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