Device and method for preparing anhydrous lower alcohol mixture by using Fischer-Tropsch synthesis by-product light alcohols

Abstract

A device and method for preparing an anhydrous lower alcohol mixture by using synthesis by-product light alcohols are provided. The device includes a pervaporation membrane dehydration unit, a hydrogenation unit, and an adsorption and dehydration unit which are connected in sequence through pipes, wherein the pervaporation membrane dehydration unit includes a pre-dehydration column, a raw materialheater, and a pervaporation membrane dehydrator which are connected in sequence through pipes; the hydrogenation unit includes a hydrogenated raw material heater, a hydrogenation reactor, and a hydrogenated gas-liquid separator which are connected in sequence through pipes. The adsorption and dehydration unit includes a hydrogenated light alcohol heater and an adsorption column connected in sequence through pipes. The device and method can effectively reduce the content of water and non-alcoholic oxygen-containing organic compounds in the lower alcohol mixture and improve product quality.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a device and a method for preparing anhydrous low-carbon mixed alcohols by using light alcohols produced by Fischer-Tropsch synthesis. Background technique [0002] In the indirect coal liquefaction of the Fischer-Tropsch synthesis route, a large amount of water-phase by-products are inevitably produced, and the water-phase by-products are treated by oil removal, neutralization, rectification and dehydration to obtain water-containing light alcohols, mainly low-carbon alcohols ( methanol, ethanol, propanol, butanol) and water, also contains aldehydes (acetaldehyde, propionaldehyde, butyraldehyde), ketones (acetone, methyl ethyl ketone, pentanone, hexanone), esters (methyl acetate, ethyl acetate ) and other non-alcoholic low-carbon oxygen-containing organic compounds. [0003] The water in the Fischer-Tropsch synthesis by-product light alcohol forms an alcoh...

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Problems solved by technology

[0012] 2) Extractive distillation method, the extraction agent is extracted from the tower kettle, the energy consumption is small, but the requirements for the extraction agent recovery tower are strict, the solvent is partially lost, and new components are introduced, and there are residues in the product;

[0013] 3) Pervaporation membrane separation method has low energy consumption and high alcohol selectivity, but the by-product light alcohol of Fischer-Tropsch synthesis contains a relatively high content of methanol. Since the molecular diameter of methanol is close to that of commonly used membrane pores, there is loss of methanol

If membrane separation method is used for deep dehydration, the number of membrane modules is large and the cost is high;

[0014] 4) Molecular sieve adsorption method has a simple process and does not introduce new substances. The process is green and environmentally friendly, and the resulting product has high purity, but the by-product of Fischer-Tropsch synthesis, light alcohol, has a high water content. The bed is easy to overheat, the regeneration process is complicated, and the operation is difficult

[0015] The prior art adopts a single dehydration technology when separating light alcohols by-products of Fischer-Tropsch synthesis, which has poor technical adaptability, and does not fully consider the actual situation that both water and non-alcoholic oxygen-containing organic compounds in light alcohols are high, resulting in The content of non-alcoholic oxygenated organic compounds is high, and the alcohol content is not up to standard

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