Method for separating and filtering molecular sieve crystallization slurry

Abstract

The invention relates to a separation and filtering method of molecular sieve crystallization slurry. The method comprises the following steps: (a) injecting a molecular sieve crystallization slurry serving as a primary slurry into a sedimentation device; (b) settling the primary slurry in the sedimentation device, layering solid and liquid to form an upper mother solution and a lower solid sediment; (c) taking out the layered upper mother solution from the sedimentation device; (d) adding water into the residual solid sediment in the sedimentation device; (e) uniformly mixing the solid sediment with the added water to form a diluted slurry; and (f) delivering the diluted slurry to a filter device to filter. According to the invention, the method has the advantages of simplicity in operation, good economy, high separation efficiency and less environmental pollution and hurt to health of operators.

Description

technical field [0001] The invention provides a method for separating and filtering molecular sieve crystallization slurry, especially SAPO molecular sieve crystallization slurry. Background technique [0002] The successful development of methanol to olefin technology (MTO, Methanol to Olefin) has found a new raw material route for olefin production. Using methanol as raw material instead of oil to produce olefins can not only free the price of olefins from the influence of petroleum products, reduce human overreliance on oil resources, but also has a very important strategy for promoting industrial development in oil-poor areas and using mineral energy in a balanced and reasonable manner significance. [0003] A key point in the successful development of MTO technology is the research and development of silicoaluminophosphate molecular sieve catalysts with excellent performance, mainly the development of SAPO-34 molecular sieve catalysts. Its active ingredient is SAPO-34...

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Problems solved by technology

Chinese patent CN1261215C discloses a nano-molecular sieve filtration method. In this method, an alkaline substance is added before the nano-molecular sieve to make the solution pH ≥ 12, so as to prevent uncrystallized SiO 2 Agglomeration; CN1195678C discloses a kind of filtration method of Y-type molecular sieve water slurry, added alkali or the mixture of alkali and salt in slurry during filtration, this method can significantly accelerate the filtration speed of cross-baked Y-type molecular sieve water slurry, but The above two methods increase the production cost, and the addition of new species will inevitably cause changes in the physicochemical and catalytic performance of molecular sieves.

[0010] Chinese patent CN1191125C discloses a method for separating molecular sieve catalysts in a ketone ammonia oximation reaction system. This method adopts a gravity sedimentation method to separate titanium-silicon molecular sieves, but this method is only used for low-carbon alcohols, ammonia water, cyclohexanone and Ketoaminoximation reaction system composed of hydrogen peroxide

However, this filtration method will encounter the following problems when dealing with SAPO series molecular sieve crystallization slurry: the pH of the slurry is too high, which will increase the corrosion of the plate and frame filter cloth and equipment; the concentration of triethylamine in the mother liquor is too high , causing great damage to the health of operators; the silica sol in the mother liquor will be mixed into the middle of the crystal particles, causing pollution of the crystal particles; the centralized recovery of the mother liquor is inconvenient; Industrial production

[0012] It can be seen that the above-mentioned separation techniques have all proposed the method of separating and filtering the crystallization slurry of small-grained molecular sieves, but there are different defects. The separation method for the crystallization slurry in the industrial production of SAPO series molecular sieves has not yet formed a mature method. Technology

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