KR20040033335A - A method for controlling the viscosity of oil in btx recovery process - Google Patents

Abstract

PURPOSE: A method for controlling viscosity of absorption oil in a light oil(BTX) recovery process is provided to enhance redistillation rate of absorption oil without BTX, to improve quality of absorption oil without BTX, and to minimize replenishment of new absorption oil. CONSTITUTION: The method for controlling viscosity of absorption oil in a light oil(BTX) recovery process includes the steps of: producing a superheated gas by passing saturated vapor through a heat exchanger(200) that recollects sensible heat from a flare generated from a furnace(40); recovering aging of absorption oil(20) without BTX; exhausting 20-25% of absorption oil(20) without BTX from the bottom of a distillation tower(50) to a pitch-free tower(60); and supplying elements from the top of the pitch-free tower(60) to the distillation tower and transmitting pitch elements from the bottom of the pitch-free tower(60) to a tar decanter(150).

Description

A viscosity control method for oil absorption in landscape oil recovery process {A METHOD FOR CONTROLLING THE VISCOSITY OF OIL IN BTX RECOVERY PROCESS}

The present invention relates to a method for managing absorbent oil viscosity in a landscape oil recovery process, and more particularly, to recover devented oil by providing superheated steam to a distillation column and a stripping column in a diesel oil process in a Hwasung plant, thereby being included in coke oven gas (COG). How to manage the viscosity of absorbent oil in the landscape oil recovery process that can effectively manage the viscosity of absorbent oil that collects BTX oil to improve the re-distillation efficiency of de-bend oil, and reduce energy and cost by minimizing replenishment of new absorbent oil It is about.

In general, in the diesel fuel process of the Hwaseong plant, as shown in FIG. 1, in order to recover landscape oil contained in coke oven gas, absorption oil is used as an absorption liquid, and the landscape oil collection tower 10 collects the landscape oil. After that, the landscape oil contained in the absorption oil is produced by using steam in a distillation process (steam stripper).

Here, the absorbent oil for absorbing the landscape oil in the coke oven gas is contained in the oil 30, and in the distillation column 50, the oil and the oil 90 come into contact with the oil to remove the landscape oil, thereby absorbing the oil without the landscape oil component. Thalbenyu (20) is called.

The room temperature oil Benzene 30 flowing out of the landscape oil collection tower 10 is passed through a heat exchanger 70, 72, 71 is maintained at 180 ℃ through a step-up temperature increase process is supplied to the distillation tower (50). . In this process, the 180 ° C. ben oil 30 supplied to the middle portion of the distillation column 50 is absorbed using a saturated steam of 6 Kgf / cm 2 at 165 ° C. supplied to the bottom of the distillation column 50. After extracting only the landscape oil to the upper portion of the distillation column 50 using the boiling temperature difference, the heat exchanger 70 through the cooling process to produce pure landscape oil (BTX).

In addition, the lower side of the distillation column 50 generates devented oil from which landscape oil has been removed, and is recovered to the landscape oil collection tower 10 again, and some of the distillation column 50 has a pitch removed from the degassing column 60. Return to).

As described above, the hamben oil 30 containing the landscape oil in the coke oven gas is brought into contact with the hot steam and reused, and thus the benzene phenomenon 20 deteriorates the ability to absorb the landscape oil. In addition, the viscosity control of the talben oil 20 is an important management item of the landscape oil recovery process in the circulating in the process of the benzene oil 30 and the talben oil 20.

If the viscosity of the desorbed oil 20 is high, the landscape oil absorption rate in the landscape oil absorption tower 10 may be lowered, and the piping may be performed in the heat exchangers 70, 71, 72, and 73 in the heat exchange process. This will cause the process to close and cause disadvantages in process stability.

Therefore, in order to manage the viscosity of the de-bend oil 20, the de-bend oil 20 is supplied to the de-pitching column 60 to supply saturated steam 90 at 6 Kgf / cm < 2 > Although removed, the distillation efficiency was low and had no effect on viscosity control.

This was to produce water by condensation of water in saturated steam while the saturated steam lowered the viscosity of talben oil. As a result, in the distillation column 50 and the depitching column 60, since water is mixed in the talben oil, the quality of the talben oil is poor and the aging component is not improved.

Therefore, conventionally, a large amount of fresh absorbent oil is supplemented to the landscape oil collection tower 10 in order to improve performance of talben oil, which is deteriorated in efficiency, thereby causing a large increase in work cost.

The present invention is to solve the conventional problems as described above, to improve the re-distillation efficiency of the de-bend oil in the distillation column and the de-pitched column, to improve the quality of the de-bend oil to improve the quality of the de-bend oil, and thus the new absorption It is an object of the present invention to provide a method for managing absorbed oil viscosity in a landscape oil recovery process that can reduce energy and cost by minimizing replenishment.

1 is a process chart showing the absorption oil viscosity management method of the landscape oil recovery process according to the prior art;

2 is a process chart showing a method for managing the absorption oil viscosity in the landscape oil recovery process according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 .... absorption tower 20 .... Talbenyu

30 ... Hambenu 40 .... Furnace

50 .... Distillation column 60 .... Depitch tower

70,71,72,73 .... Heat Exchanger 80 Exhaust Doctor

90 .... Steam 100 .... Coke Oven Gas

150 .... Tardecanter 200 ... Heat Exchanger

300 .... Stack

In order to achieve the above object, the present invention, in the method for managing the viscosity of the absorbent oil in the landscape oil recovery process of Hwaseong factory,

Producing a superheated steam by passing a saturated steam by installing a heat exchanger for recovering sensible heat in flue gas generated from a heating furnace using coke oven gas (COG) as a raw material;

Restoring aging of the talben oil by supplying superheated steam to the distillation column and the depitch column in the heat exchanger; Discharging 20 to 25% of the benzene from the distillation column bottoms to the de-pitching column; and re-distillation of the de-pitching tower and the components from the column top are re-supplied to the distillation column, and the pitch component from the tower bottom is tardecanter. By sending a separation treatment; including by absorbing oil viscosity of the landscape oil recovery process, characterized in that to restore the performance of the de-bend oil.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In the absorbent oil viscosity management method of the landscaping oil recovery process according to the present invention, as shown in FIG. 2, a heat exchanger is installed in a heating furnace 40 using coke oven gas (COG) 100 as a raw material, and a heating furnace. Recovering the sensible heat in the flue-gas generated in the production process to produce a saturated steam of 165 ℃ 6Kgf / cm2 as superheated steam of 195 ℃ ~ 210 ℃ to supply to the distillation tower (50) and de-pitching column (60).

These steps are carried out in the heat exchanger 70 in order to increase the temperature to the appropriate temperature for supplying the oil bent oil (30) in the coke oven gas in the landscape oil absorption tower 10 to the distillation column (50) ( 72) (71) passes through the heating furnace 40 which is the final temperature raising step. At this time, in the heating furnace 40, the coke oven gas 100 is burned to raise the ben-oil 30, but most of the sensible heat generated in the exhaust gas is sent to the stack 300 and discharged.

Therefore, the heat exchanger 200 is installed in the exhaust gas duct 80 connecting the heating furnace 40 and the stack 300 to heat the saturated steam and the exhaust gas, thereby heating the saturated steam at 165 ° C. to the superheated steam at 195˜210 ° C. will be.

In this process, the superheated steam temperature may be elevated to higher than 195 ° C. to 210 ° C. by adjusting the flow rate of the coke oven gas 100 supplied to the furnace 40, but the temperature of the furnace 40 is thus excessively increased. When the temperature rises, the temperature of the ben-oil 30 passing through the heat exchanger 71 of the heating furnace 40 and supplied to the distillation column 50 becomes too high, thereby promoting the aging of the ben-oil 30 and closing the pipe. Will cause.

Therefore, the appropriate superheated steam at 195 ° C to 210 ° C is produced.

Then, the heated superheated steam supplied to the bottom of the stripping tower 60 is supplied at 1 to 1.5 tons / hour. If the supply amount is smaller than this, the aging component of the debend oil is not sufficiently recovered, and the total amount falls into the bottom of the depitching column 60, resulting in cost loss due to the decrease in absorbed oil. Due to the increase in the gas-liquid contact area between the 20 and the steam, the aging of the unnecessary debenbene 20 is accelerated.

In addition, the superheated steam supplied to the stripping column 60 has a deep correlation with the new absorbent oil replenishment amount.

Then, a step of supplying 20 to 25% of the stripped oil discharged from the bottom of the distillation column 50 to the stripped column 60 is performed. This is less than the value of 20-25% in the talben oil 20 discharged from the bottom of the distillation column 50, the aging component in the talben oil 20 circulating in the process is not sufficiently removed, the viscosity of the talben oil 20 If it becomes difficult to manage and is larger than the value of 20-25%, there will be less process circulation absorbent oil. Therefore, new absorbent oil must be replenished in a large amount, resulting in cost increase.

That is, about 20 to 25% of the benzene removed from the distillation column 50 is extracted to the leach pitch 60 to separate the pitch.

In addition, the next step is re-distilled in the depitching column 60 and the components coming out of the column top is re-supplied to the distillation column 50, the pitch component from the tower bottom is sent to the tar decanter 150 for processing. Conventionally, after re-distillation in the stripping tower 60, the soft pitch was extracted from the bottom of the stripping tower 60 to produce a product. Poor working environment is caused by toxic aromatics generated in soft pitch.

Therefore, it is possible to improve the working environment by transferring the soft pitch of the bottom product to the tardecanter 150.

In this process, the absorption oil viscosity management method of the landscaping oil recovery process according to the present invention by supplying the superheated steam of 195 ℃ ~ 210 ℃ to the distillation column and the stripping column to restore the absorption capacity of the debend oil does not contain water in the debend oil. . That is, the quality of the talben oil is improved by increasing the temperature of the talben oil and not generating water even when the viscosity is lowered.

Accordingly, the talben oil is capable of restoring aging to talben oil of good quality in which the landscape oil absorption rate in the landscape oil absorption tower 10 is improved.

Therefore, because the quality of the dehaled oil is excellent, it is possible to achieve energy and cost reduction by minimizing the replenishment of the new absorbent oil.

Hereinafter, the effect of the present invention was examined in detail through Examples and Comparative Examples.

Example 1

In order to compare the present invention with the conventional method, a series of experiments were performed for each distribution ratio from the distillation column to the de-pitching column while varying the temperature of the steam supplied to the distillation column and the stripping column, and the results are shown in Table 1 below.

Table 1

division Steam temperature (℃) Depitch Tower Talben Oil Distribution Ratio (%) Process Circulating Absorption Viscosity (° E) Renewed Absorption Supplement (Ton / Day) Technology 165 10 1.9 ~ 2.1 5 ~ 7 20 2.2 to 2.6 5 ~ 7 30 2.4 ~ 2.6 5 ~ 7 Invention 195 10 1.8 ~ 2.0 5 ~ 6.5 20 1.4-1.5 3.5 to 4.5 30 1.3 to 1.4 4 ~ 5 210 10 1.7 ~ 1.8 3.5 to 4.5 20 1.3 to 1.4 2.5 to 3.5 30 1.3 to 1.4 3.5 to 4.5

As can be seen in Table 1 above, in the case of the present invention, the superheated steam at 195 ° C. to 210 ° C. is supplied, and 20 to 25% of the benzene is discharged from the bottom of the distillation column 50 to the stripping column 60. In the case of discharge, it was possible to minimize the amount of fresh absorbent supplement while reducing the viscosity.

Example 2)

In order to compare the present invention with the conventional method, a series of experiments were performed for each distribution ratio from the distillation column to the de-pitching column while varying the amount of steam supplied to the distillation column and the stripping column, and the results are shown in Table 2 below.

TABLE 2

division Depitch Tower Steam Supply (tons / day) Depitch Tower Talben Oil Distribution Ratio (%) Process Circulating Absorption Viscosity (° E) Renewed Absorption Replenishment (ton / day) Prior art 0.5 10 2.2 to 2.4 5 ~ 7 20 2.1 ~ 2.4 5 ~ 7 30 2.2 to 2.4 5.5 ~ 7 Invention One 10 1.8-1.9 4.5-5 20 1.4-1.5 3 ~ 3.5 30 1.4-1.5 4.5 ~ 5.5 2 10 1.7 ~ 1.8 4 ~ 5 20 1.5 to 1.6 4.5 ~ 5.5 30 1.45-1.55 5 ~ 6

As can be seen in Table 2 above, the distribution ratio of the fugitive oil to the stripping tower and the amount of steam supplied showed a great influence on the viscosity management, and the superheated steam was supplied at 1 ~ 1.5 ton / hour in terms of cost reduction and 20 ~ In the case of discharging 25% to the de-pitching tower 60, it was found that there is an optimum point to minimize the amount of new absorbent oil while reducing the viscosity.

As described above, according to the present invention, the re-distillation efficiency of talbend oil is improved by supplying superheated steam instead of saturated steam to the distillation tower and the depitch column in the landscape oil recovery process of absorbing landscape oil (BTX) in the coke oven gas as absorbent oil in the steel mill. And, to ensure good quality of the Thalben oil, to improve the quality of Thalben oil, and to achieve the effect of energy and cost reduction by minimizing the replenishment of the new absorbent oil accordingly.

Claims (3)

In the method of managing the viscosity of absorbent oil in the landscape oil recovery process of Hwaseong plant, Producing a superheated steam by passing a saturated steam by installing a heat exchanger for recovering sensible heat in flue gas generated from a heating furnace using coke oven gas (COG) as a raw material; Restoring aging of the talben oil by supplying superheated steam to the distillation column and the depitch column in the heat exchanger; Discharging 20 to 25% of the benzene from the distillation tower bottom from the bottom of the distillation column; and Re-distillation from the de-pitched column and the component coming out of the tower top is re-supplied to the distillation column, the pitch component from the bottom bottom to send to the tardecanter for separation treatment; recovering landscape oil, characterized in that to restore the performance of the talben oil Absorption oil viscosity control method of process. The method of claim 1, wherein the absorbed oil viscosity management method of the landscape oil recovery process, characterized in that for supplying the heated superheated steam at 1 ~ 1.5 tons / hour to the stripping column (60). The method of claim 1, wherein the superheated steam is 195 ° C ~ 210 ° C absorption oil viscosity management method of the landscape oil recovery process.