Method for separating phenolic substances in medium-low temperature coal tar

A technology of low-temperature coal tar and phenolic substances, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as unfavorable environmental protection, complexity, and large amount of wastewater

Active Publication Date: 2020-10-30

CHAMBROAD CHEM IND RES INST CO LTD

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AI-Extracted Technical Summary

Problems solved by technology

[0002] At present, medium and low temperature coal tar contains a large amount of phenols, and the separation of phenols and non-phenols is mostly carried out through auxiliary methods such as alkali washing, pickling neutralization, etc. The operating procedures are many and complicated, and the product recovery rate is low. Moreover, the amount of wastewater in the process is large, and the cost of subsequent sewage treatment is high, which is not conducive to environmental prote...

Method used

[0072] Through the method for separating phenolic substances in low-temperature coal tar of the present invention, the obtained phenolic content is more than 99.32%; but through the separation method of Comparative Example 1, the obtained phenolic content is only 91.42%. The present invention adopts a mixed extractant and adopts two extraction and separation process...

Abstract

The invention belongs to the field of separation and purification technologies in the chemical industry and particularly relates to a method for separating phenolic substances from medium and low temperature coal tar. A two-step extraction separation process is adopted, and phenolic substances with the purity being greater than 99% are separated. The method comprises the following specific steps of: mixing medium and low temperature coal tar with a mixed extraction agent, settling to obtain a phenol-rich component, enabling the phenol-rich component to enter an extraction tower, enabling heavycomponents at the tower bottom to enter a recovery tower 2, enabling a tower top component of the recovery tower 2 to enter a recovery tower 3, and enabling a tower bottom component of the recovery tower 3 to be the phenol substances. The separation process provided by the invention has the advantages of simple operation conditions, low extraction agent price, stable properties, low equipment investment and energy consumption, high phenol recovery rate, recyclable extraction agent and no generation of three wastes.

Application Domain

Organic chemistryOrganic compound preparation +1

Technology Topic

PhysicsChemical industry +7

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Examples

Experimental program(3)
Comparison scheme(1)

Example Embodiment

[0030] Example 1

[0031] A method for separating phenolic substances from medium and low temperature coal tar. The medium and low temperature coal tar adopts a two-part extraction and separation process to separate phenolic substances with a purity greater than 99%. The specific steps are as follows:

[0032] (1) The medium and low temperature coal tar and the mixed extractants A and B are mixed uniformly in a certain proportion, and after sedimentation and stratification, the upper layer is non-phenolic substance 1, and the lower layer is phenol-rich solvent;

[0033] (2) The separated phenol-rich solvent enters the extraction tower from the upper end of the tower, and the extractant C enters the extraction tower from the lower end of the tower, and undergoes countercurrent extraction;

[0034] (3) The top component of the extraction tower enters the recovery tower 1, the top component of the recovery tower 1 is the extractant C, which is recycled, and the bottom component is the non-phenolic substance 2;

[0035] (4) The bottom component of the extraction tower enters the recovery tower 2, the bottom component of the recovery tower 1 is the extractant A, which is recycled, and the top component enters the recovery tower 3;

[0036] (5) The top component of the recovery tower 3 is non-phenolic substance 3. After the non-phenolic substance 3 is left to stand for layering, the upper layer is non-phenolic substance 4, and the lower layer is extractant B, which is recycled; the bottom component of recovery tower 3 Is a phenolic substance;

[0037] (6) Non-phenolic substances 1, 2 and 4 are used as oil blending components to blend diesel;

[0038] The mass ratio of extractant A and extractant B in mixed extractant A and B is 5:1; the mass ratio of medium and low temperature coal tar to mixed extractant is 5:12; the ratio of extractant C to medium and low temperature coal tar is 1: 1;

[0039] The top temperature of recovery tower 1 is 69.4℃, the top pressure is 110Kpa (absolute pressure), and the bottom temperature is 172.5℃; the top temperature of recovery tower 2 is 119.7℃, the top pressure is 20Kpa (absolute pressure), and the bottom temperature is The temperature at the top of the recovery tower 3 is 88.6°C, the pressure at the top of the tower is 20Kpa (absolute pressure), and the temperature at the bottom of the tower is 157.4°C.

[0040] The total content of phenols in the product after separation is 99.32%.

Example Embodiment

[0041] Example 2

[0042] A method for phenolic substances in medium and low temperature coal tar. The medium and low temperature coal tar adopts a two-part extraction and separation process to separate phenolic substances with a purity greater than 99%. The specific steps are as follows:

[0043] (1) The medium and low temperature coal tar and the mixed extractants A and B are mixed uniformly in a certain proportion, and after sedimentation and stratification, the upper layer is non-phenolic substance 1, and the lower layer is phenol-rich solvent;

[0044] (2) The separated phenol-rich solvent enters the extraction tower from the upper end of the tower, and the extractant C enters the extraction tower from the lower end of the tower, and undergoes countercurrent extraction;

[0045] (3) The top components of the extraction tower enter the recovery tower 1, the top of the recovery tower 1 is the extractant C, which is recycled, and the bottom of the tower is the non-phenolic substance 2;

[0046] (4) The bottom component of the extraction tower enters the recovery tower 2, the bottom component of the recovery tower 1 is the extractant A, which is recycled, and the top component enters the recovery tower 3;

[0047] (5) The top component of the recovery tower 3 is non-phenolic substance 3. After the non-phenolic substance 3 is left to stand for layering, the upper layer is non-phenolic substance 4, and the lower layer is extractant B, which is recycled; the bottom component of recovery tower 3 Is a phenolic substance;

[0048] (6) Non-phenolic substances 1, 2 and 4 are used as oil blending components to blend diesel;

[0049] The mass ratio of extractant A and extractant B in mixed extractant A and B is 10:3; the mass ratio of medium and low temperature coal tar to mixed extractant is 5:13; the ratio of extractant C to medium and low temperature coal tar is 1: 1

[0050] The top temperature of recovery tower 1 is 68.4℃, the top pressure is 120Kpa (absolute pressure), and the bottom temperature is 171.3℃; the top temperature of recovery tower 2 is 120.2℃, the top pressure is 20Kpa (absolute pressure), and the bottom temperature is The temperature at the top of the recovery tower 3 is 88.3℃, the pressure at the top of the tower is 20Kpa (absolute pressure), and the temperature at the bottom of the tower is 159.6℃;

[0051] The total content of phenolic substances in the product after separation is 99.51%.

Example Embodiment

[0052] Example 3

[0053] A method for separating phenolic substances from medium and low temperature coal tar. The medium and low temperature coal tar adopts a two-part extraction and separation process to separate phenolic substances with a purity greater than 99%. The specific steps are as follows:

[0054] (1) The medium and low temperature coal tar and the mixed extractants A and B are mixed uniformly in a certain proportion, and after sedimentation and stratification, the upper layer is non-phenolic substance 1, and the lower layer is phenol-rich solvent;

[0055] (2) The separated phenol-rich solvent enters the extraction tower from the upper end of the tower, and the extractant C enters the extraction tower from the lower end of the tower, and undergoes countercurrent extraction;

[0056] (3) The top components of the extraction tower enter the recovery tower 1, the top of the recovery tower 1 is the extractant C, which is recycled, and the bottom of the tower is the non-phenolic substance 2;

[0057] (4) The bottom component of the extraction tower enters the recovery tower 2, the bottom component of the recovery tower 1 is the extractant A, which is recycled, and the top component enters the recovery tower 3;

[0058] (5) The top component of the recovery tower 3 is non-phenolic substance 3. After the non-phenolic substance 3 is allowed to stand for stratification, the upper layer is non-phenolic substance 4 and the lower layer is extractant B, which is recycled; the bottom component of recovery tower 3 Is a phenolic substance;

[0059] (6) Non-phenolic substances 1, 2 and 4 are used as oil blending components to blend diesel;

[0060] The mass ratio of extractant A to extractant B in mixed extractant A and B is 5:2; the mass ratio of medium and low temperature coal tar to mixed extractant is 5:14; the ratio of extractant C to medium and low temperature coal tar is 1: 1

[0061] The top temperature of recovery tower 1 is 68.1℃, the top pressure is 110Kpa (absolute pressure), and the bottom temperature is 171.7℃; the top temperature of recovery tower 2 is 120.5℃, the top pressure is 20Kpa (absolute pressure), and the bottom temperature is The temperature at the top of the recovery tower 3 is 87.9°C, the pressure at the top of the tower is 20Kpa (absolute pressure), and the temperature at the bottom of the tower is 158.4°C;

[0062] The total content of phenolic substances in the product after separation is 99.67%.

PUM

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