JPH048471B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention dehydrates crude tar produced during coking of coal in a dehydration tower, and separates the dehydrated tar into boiling components and pitch in a pitch tower. Regarding the method.

[Conventional technology]

Such a method is known from JP-A-62-13488. In this method, Pitzchi column (distillation column)
The crude tar and the bottom product of the dehydration tower are preheated via a heat exchanger by the bottom product of the dehydration tower. Thereby it is possible to save energy and improve thermal efficiency for processing crude tar. Furthermore, in this method, in order to further improve the thermal efficiency, a part of the bottom product of the dehydration tower is refluxed to the dehydration tower via a line before being fed to the Pitch tower. Requires additional equipment such as a reboiler.

[Problem to be solved by the invention]

An object of the present invention is to provide a method for treating coarse tar that makes it possible to further improve thermal efficiency without requiring the above-mentioned additional equipment.

[Means to solve the problem]

In order to solve this problem, according to the invention, the bottom product of the Pitz column preheats the crude tar and the bottom product of the dehydration column via a heat exchanger, and the top product of the Pitch column preheats the heat exchanger. The crude tar and the bottom product of the dehydration tower are preheated via the filtrate.

〔Effect of the invention〕

In this way, according to the present invention, the heat of condensation of not only the bottom product of the Pitzchi column but also the head product of the Pitch column is used to preheat the crude tar and the bottom product of the dehydration column, so that it is possible to preheat the crude tar and the bottom product of the dehydration column. Thermal efficiency is significantly improved compared to the dehydration tower, and there is no need to return part of the bottom product of the dehydration tower to the dehydration tower before it is fed to the Pitch tower. Moreover, the easily boiling components as the head product of the pitsch column are used to preheat the crude tar and the bottom product of the dehydration column, so that their temperature decreases and condenses, thus causing this to condense. There is also no need for a condenser.

[Embodiment]

The high-boiling pitch component can be mixed into the coal charge of the coke plant during coking. The coking properties are thereby improved particularly economically.

Furthermore, the above-mentioned process embodiment provides the possibility of economically processing the crude tar in coke plants where it is produced in each case. Therefore, transportation costs to the central processing facility become unnecessary.

〔Example〕

As schematically shown in the figure, the crude tar removed from the tar separator and containing about 4-5% water by weight is
First, it is preheated to about 155°C in heat exchangers 1 and 2, and then led to a dehydration tower 3. Dehydrated tar forms as bottom product and is fed to further heat exchangers 6,7.

A mixture of water and light oil is taken out from the head of the dehydration tower 3, cooled in a condenser 4, and separated from each other in a separator 5. Some light oil is returned to the dehydration tower 3 as reflux.
The remainder can be returned to the head of the machine and the remainder is recovered as a product and mixed with, for example, de-pitched tar.

The tar taken off as the bottom product of the dehydration tower 3 is preheated in further heat exchangers 6 and 7 by heat exchange with tar vapor and pitch, and finally about.
Heated from 320℃ to approximately 365℃. Due to the integrated thermal coupling circuit, external heat is supplied only for this temperature increase of 45° C., for example in the reheat boiler furnace 8.

In the pitch column 9, which is operated at approximately 0.5 bar, the tar is separated into the pitch fraction and easily boiling components by vacuum flash evaporation without reflux.
The freezing point of the pitch can be adjusted, for example, by slight changes in the degree of vacuum. A vacuum pump is used to adjust the pressure.

In the example of a coke plant charged with 700 tons of wet coal per day, the following quantity accounts are obtained:

5,600 tons of wet coke is produced per day.
In a coke plant that is charged with 7800 tons of wet coal per day and produces about 11 tons of crude tar per hour, the composition of the crude tar is as follows:

Water approx. 3% by weight Light oil 1% by weight Boils at 180-230℃ 7% by weight Boils at 230-270℃ 10% by weight Boils at 270-300℃ 4.5% by weight Boils at 300-360℃ 20% by weight Pituchi (freezing point 67) °C) 54.5% by weight Crude tar inlet temperature to the processing equipment approximately 55°C As a result, the process according to the invention has minimal energy demands. This minimal energy requirement is possible due to the specially selected pressure and temperature step reduction and thermal coupling circuit.

In the process according to the invention, crude tar fractions gas oil and pitch are produced, which offer various subsequent processing possibilities.

Another consideration is that the cost of transporting the water and pitch components (approximately 57% by weight) of the crude tar to the central treatment facility is eliminated. It also reduces the cost of distillative separation of crude tar in central processing facilities,
The cost of processing pitch in a central processing facility or transporting pitch back to the coke factory is eliminated.

[Brief explanation of drawings]

The figure is a flowchart of the method according to the invention. 1, 2, 6, 7...heat exchanger, 3...dehydration tower, 9...
Pituchi Tower.

Claims (1)

[Scope of Claims] 1. A method in which crude tar produced during the coking of coal is dehydrated in a dehydration tower, and the dehydrated tar is separated into boiling components and pitch in a pitch tower, in which heat exchange is performed by the bottom product of pitch tower 9. The crude tar and the bottom product of the dehydration tower 3 are preheated via the reactors 2 and 7, and the crude tar and the bottom product of the dehydration tower 3 are preheated by the head product of the pitch column 9 via the heat exchangers 1 and 6. A method for treating coarse tar, which is characterized by preheating. 2, characterized in that the high boiling point pitch component from the pitch column 9 is mixed into the charging coal for coke production;
A method according to claim 1.