Method for increasing melting temperature of Fischer-Tropsch wax

Abstract

The invention discloses a method for increasing melting temperature of Fischer-Tropsch wax. The method comprises steps as follows: step one, the Fischer-Tropsch wax and a solvent which is 0.02-5.0 times the weight of the Fischer-Tropsch wax are mixed in a liquid state, a mixed solution is cooled and solidified in 1-24 h, and a crystallized mixture of the Fischer-Tropsch wax and the solvent is obtained; step two, the crystallized mixture of the Fischer-Tropsch wax and the solvent remains at constant temperature of 30-120 DEG C for 2-24 h, part of the crystallized mixture of the Fischer-Tropschwax and the solvent is melted, and the un-melted crystallized mixture and the melted crystallized mixture are separated; step three, the Fischer-Tropsch wax and the solvent in the un-melted crystallized mixture are separated, the Fischer-Tropsch wax with high melting temperature is obtained, the Fischer-Tropsch wax and the solvent in the melted crystallized mixture are separated, the Fischer-Tropsch wax with low melting temperature is obtained, and the solvent is recovered and recycled. The method has the advantages as follows: high temperature and high vacuum degree are not needed, energy issaved, the hidden danger of adverse effect of the high temperature on performance of the Fischer-Tropsch wax is avoided, no three wastes are produced, and the Fischer-Tropsch wax in different meltingtemperature ranges can be obtained as required.

Description

technical field [0001] The invention relates to a method for increasing the melting temperature of n-paraffin mixtures, more precisely a method for increasing the melting temperature of Fischer-Tropsch wax, which belongs to the field of fine chemicals. Background technique [0002] Using coal, water vapor, air or oxygen as raw materials, reacting at a certain temperature, the coal can be converted into a mixture of carbon monoxide and hydrogen, that is, water gas or semi-water gas. After the mixture is purified, carbon monoxide and hydrogen are used as the Raw materials, chemical reaction, can get methanol, acetic acid, vinyl acetate and other chemical products. [0003] Fischer-Tropsch synthesis belongs to the indirect liquefaction technology of coal. It uses carbon monoxide and hydrogen as raw materials, and under the action of iron-based or cobalt-based catalysts, chemical reactions are carried out at a certain temperature and pressure to obtain normal alkanes. The main ...

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Problems solved by technology

[0004] The n-alkanes in the Fischer-Tropsch wax have two characteristics. One is that the number of carbon atoms in the n-alkanes is relatively large, and the number of carbon atoms may be more than 120. The other feature is that the number of carbon atoms in the n-alkanes is distributed in a wide range. From 18 carbon atoms all the way to 120, or even higher, resulting in a wider melting temperature range of Fischer-Tropsch wax, which cannot meet the quality requirements of the high-end market for Fischer-Tropsch wax. Therefore, developing Fischer-Tropsch wax with a narrow melting temperature range and improving The melting temperature of Fischer-Tropsch wax has become a problem to be solved. Patent CN02814083.4 discloses a preparation method of Fischer-Tropsch wax. Wax, to improve the purity of Fischer-Tropsch wax, patent CN103980940A proposes a method for obtaining high-melting-point Fischer-Tropsch wax by high-vacuum distillation, and patent CN104673383B proposes an improved vacuum distillation method to obtain high-melting-point Fischer-Tropsch wax, and the application number is 2011102266326 The patent disclosed a method, the main point of which is to transport the crude wax component from the Fischer-Tropsch synthesis system to the sweating tank by the raw material pump after hydrogenation refining, and remove the lipids in the wax component through sweating. Both patents involve the use of high temperature and high vacuum. Since there are more carbon atoms in the normal alkanes in Fischer-Tropsch wax, the distillation effect is affected by the boiling point of the normal alkanes, and the cost of high vacuum is also very high. The n-paraffins in the Fischer-Tropsch wax are finely divided. The last method is limited by the melting point of the high-melting-point components of the Fischer-Tropsch wax and the viscosity of the low-melting-point components in the Fischer-Tropsch wax. The sweating effect is not ideal.

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