METHOD OF PRODUCING SERIES OF PHASE-CHANGE WAX PRODUCTS

Abstract

Disclosed is a method for producing series of phase change wax products, comprising: refining a Fischer-Tropsch synthesis wax raw material via a hydrogenation reaction to obtain a refined Fischer-Tropsch wax; and subjecting the refined Fischer-Tropsch wax to reduced pressure distillation to separate continuous fractions with a distillation range of 5 C.-30 C. by continuously increasing the operation temperature so as to obtain series of phase change wax products, wherein the pressure for the reduced pressure distillation is 0-1000 pa, the operation temperature at the top of the column is 120 C.-260 C., and the phase change enthalpy value of the series of phase change wax products is 170 J/g. According to the method, phase change wax products of various grades with melting points from 5 C. to 80 C. can be separated and produced from the refined Fischer-Tropsch wax. The products have concentrated carbon numbers and relatively high enthalpy values. The process products have relatively high flexibility, can be customized on demand, and have low production cost, and the industrial production of the products can be realized.

Claims

1. A method of producing series of phase-change wax products, characterized in that it comprises: refining a Fischer-Tropsch synthesis wax raw material via a hydrogenation reaction to obtain a refined Fischer-Tropsch wax; subjecting the refined Fischer-Tropsch wax to reduced pressure distillation, separating continuous fractions with a distillation range of 5-30 C. by continuously increasing the operation temperature, to obtain series of phase-change wax products, wherein the pressure for the reduced pressure distillation is 0-1000 pa, the operation temperature at the top of the column is 120-260 C., and the phase -change enthalpy value of the series of phase-change wax products is 170 J/g.

2. The method of claim 1, wherein the operation temperature of the hydrogenation reaction is 240-340 C., and the operation pressure is 3-8 MPa.

3. The method of claim 1, wherein the freezing point of the refined Fischer-Tropsch wax is 40-90 C.

4. The method of claim 1, wherein the method further comprises, before the reduced pressure distillation, reducing the content of isomeric-hydrocarbon in the refined Fischer-Tropsch wax to increase the content of normal-alkane in the raw material to 95% or more.

5. The method of claim 4, wherein the method of reducing the content of isomeric-hydrocarbon in the refined Fischer-Tropsch wax is selected from sweating or solvent deoiling.

6. The method of claim 5, wherein the solvent deoiling includes dilution with butanone and crystallization in steps.

7. The method of claim 1, wherein the reduced pressure distillation comprises: under the conditions of a pressure of 1000 Pa and an operation temperature of 140-150 C. at the top of the column, the fraction at the temperature of 280-300 C. is separated, with a melting point of 152.5 C. and a phase-change enthalpy value of 170 J/g; under the condition of an operation temperature of 150-160 C. at the top of the column, the fraction at the temperature of 300-315 C. was separated, with a melting point of 202.5 C. and a phase-change enthalpy value of 170 J/g; under the condition of an operation temperature of 160-170 C. Cat the top of the column, the fraction at the temperature of 315-330 C. was separated, with a melting point of 252.5 C. and a phase-change enthalpy value of 170 J/g; series of phase-change wax products having a melting point of 60 C. can be separated by continuously increasing the operation temperature.

8. The method of claim 1, wherein the reduced pressure distillation comprises: under the conditions of a pressure of 10 Pa and an operation temperature of 115-130 C. at the top of the column, the fraction at the temperature of 350-375 C. was separated, with a melting point of 352.5 C. and a phase-change enthalpy value of 180 J/g; under the condition of an operation temperature of 130-145 C. at the top of the column, the fraction at the temperature of 375-400 C. was separated, with a melting point of 452.5 C. and a phase-change enthalpy value of 190 J/g; under the condition of an operation temperature of 145-160 Cat the top of the column, the fraction at the temperature of 400-425 C. was separated, with a melting point of 502.5 C. and a phase-change enthalpy value of 190 J/g; series of phase-change wax products having a melting point of 60 C. can be separated by continuously increasing the operation temperature.

9. The method of claim 1, wherein the carbon number of each phase-change wax product is 3-5.

10. The method of claim 1, wherein the phase-change temperature of the series of phase-change wax products is 5-80 C.

Description

SPECIFIC MODE FOR CARRYING OUT THE INVENTION

[0023] In order to make the purposes, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to specific Examples.

[0024] In the present invention, Fischer-Tropsch synthetic wax is selected as a raw material for preparing series of phase-change wax products, and a method for preparing a phase-change wax with a simple process is provided, including the following steps: firstly, the Fischer-Tropsch synthetic wax is refined by hydrogenation reaction, to effectively remove substances such as olefins, oxygen-containing compounds and the like which may influence the product quality. The refined Fischer-Tropsch wax is treated by solvent removal of isomeric-hydrocarbon to make the content of normal-alkane to be 95% or more; Through separation by reduced pressure distillation and controlling the distillation range of the separated fraction within 5-30 C., series of phase-change wax products with high-quality can be separated, wherein the content of normal-hydrocarbon is 95% or more and the carbon number is mainly 3-5 carbons. This method has the following advantages: realizing customized production on demand, realizing the full utilization of raw materials, reducing waste, reducing costs and effectively improving economic benefit.

[0025] In one embodiment, a low-temperature Fischer-Tropsch synthetic wax is used as a raw material, and a refined Fischer-Tropsch wax is obtained by hydrogenation reaction. The operation temperature of the hydrogenation reaction is 240-340 C., and the operation pressure is 3-8 Mpa. The purpose of refinement by hydrogenation reaction is to saturate a small amount of olefins in the Fischer-Tropsch synthetic wax, reduce a small amount of oxygen-containing organic compounds in the Fischer-Tropsch synthetic wax and break the chains of a small amount of polycyclic hydrocarbons in the Fischer-Tropsch synthetic wax.

[0026] If these substances are not removed, on the one hand, they will affect the color of the products separated from Fischer-Tropsch wax, and on the other hand, it is easy to generate coking and carbon deposition in the subsequent processing, thereby influencing the quality and normal production of the products. The isomeric-hydrocarbon can be further removed from the refined Fischer-Tropsch wax by sweating, solvent deoiling and other means of removing isomeric hydrocarbons.

[0027] In one embodiment, a butanone solvent is used as a single solvent to dilute the oil-containing Fischer-Tropsch wax, and after a pre-dilution, first dilution, second dilution and third dilution and crystallization by cooling, a solvent-containing crystallization liquid is obtained. The crystallization liquid is filtered by a filter to obtain deoiled cerate, and the deoiled cerate is evaporated to recover the solvent to obtain the product of wax. When the dilution is carried out for many times, excessive consumption of cooling calories in single cooling can be avoided, and the energy consumption for cooling is saved. The normal-alkane content of the deoiled refined Fischer-Tropsch wax is increased to more than 95% (the step is determined by the normal-hydrocarbon content in the raw material, and if the normal-hydrocarbon content in the raw material reaches more than 95%, this step can be omitted).

[0028] The refined Fischer-Tropsch wax is separated in a packed rectification column with a reaction pressure of 0-1000 Pa and a temperature at the top of the column of 120-260 C. Continuous fractions with a distillation range of 5-30 C. can be separated and divided into phase-change wax products of various grades according to the melting point of each fraction. The invention can obtain series of phase change wax products with stable phase change temperature at 5-80 C.

Example 1

[0029] A low-temperature Fischer-Tropsch synthetic wax is used as a raw material and refined by hydrogenation reaction to obtain a refined Fischer-Tropsch wax, wherein the freezing point is 45 C., the initial boiling point is 286 C., and the normal-alkane content in the raw material wax is 95.3%.

[0030] The refined Fischer-Tropsch wax is subject to the following steps: under a pressure of 1000 Pa and an operation temperature of 140-150 C. at the top of the column, a fraction at the temperature of 280-300 C. is separated, with a melting point of 152.5 C. and a phase-change enthalpy value of 170 J/g; continuously increasing the operation temperature of the rectifying column, under the condition of an operation temperature of 150-160 C. at the top of the column, a fraction at the temperature of 300-315 C. was separated, with a melting point of 202.5 C. and a phase-change enthalpy value of 170 J/g; continuously increasing the operation temperature of the rectifying column, under the condition of an operation temperature of 160-170 C. at the top of the column, a fraction at the temperature of 315-330 C. was separated, with a melting point of 252.5 C. and a phase-change enthalpy value of 170 J/g; with the continuous increase of the operation temperature of the rectifying column, phase-change wax fractions of various grades with distillation range of 10 C. and melting point of 15-55 C. can be separated according to requirements and can be directly used as a phase-change wax product.

Example 2

[0031] A Fischer-Tropsch synthetic wax is used as a raw material and refined by hydrogenation reaction to obtain a refined Fischer-Tropsch wax, wherein the freezing point is 85 C., the normal-alkane content is 92.1%, and the normal-alkane content reaches 98.3% after dilution with butanone and deoiling by crystallization in steps.

[0032] The refined Fischer-Tropsch wax is subject to the following steps: under a pressure of 10 Pa and an operation temperature of 115-130 C. at the top of the column, a fraction at the temperature of 350-375 C. is separated, with a melting point of 352.5 C. and a phase-change enthalpy value of 180 J/g; continuously increasing the operation temperature of the rectifying column, under the condition of an operation temperature of 130-145 C. at the top of the column, a fraction at the temperature of 375-400 C. was separated, with a melting point of 452.5 C. and a phase-change enthalpy value of 190 J/g; continuously increasing the operation temperature of the rectifying column, under the condition of an operation temperature of 145-160 C. at the top of the column, a fraction at the temperature of 400-425 C. was separated, with a melting point of 502.5 C. and a phase-change enthalpy value of 190 J/g; with the continuous increase of the operation temperature of the rectifying column, phase-change wax fractions of various grades with distillation range of 20 C. and melting point of 25-80 C. can be separated according to requirements and can be directly used as a phase-change wax product.

[0033] The specific Examples described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific examples of the present invention and are not intended to limit the present invention, any modifications, equivalent replacements, improvements and the like sithin the spirit and principle of the present invention should be included in the scope of the present invention.