Tar distillation system

Abstract

The utility model belongs to the technical field of tar distillation, and particularly relates to a tar distillation system which comprises a tar depot, a distillation main tower and a dehydration tower, and a first heat exchanger, a second heat exchanger and a third heat exchanger are arranged between the tar depot and the dehydration tower. High-temperature side input ends of the first heat exchanger, the second heat exchanger and the third heat exchanger are respectively connected with a carbolic oil output end, a mixed part output end and a heavy absorber oil output end of the main distillation tower, and tar in the tar depot is subjected to heat exchange through the first heat exchanger, the second heat exchanger and the third heat exchanger in sequence and flows into the dehydration tower. According to the tar distillation device, the first heat exchanger, the second heat exchanger and the third heat exchanger are additionally arranged, different fractions of the main distillation tower are used as heating media to preheat tar, waste heat in the tar distillation process is fully recycled, the different fractions are cooled, energy consumption needed by follow-up heating is reduced, and therefore the production cost is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of tar distillation technology, and specifically relates to a tar distillation system. Background Technology

[0002] Coal tar distillation is a process that separates coal tar into fractions enriched with certain compounds based on the different boiling points of its components. The process consists of dehydration and fraction distillation. Dehydration is carried out under normal pressure, and then the anhydrous tar undergoes vacuum distillation in the main distillation column. Because distillation is performed under negative pressure, this process improves the operating environment and is beneficial for environmental protection.

[0003] However, the process does not fully recover the waste heat of the distillate during dehydration and fractionation. The heat released when high-temperature distillates such as phenolic oil, mixed fractions, and heavy wash oil are directly cooled is not effectively utilized, resulting in the system needing additional energy to heat the raw material tar, leading to high energy consumption. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model provides a tar distillation system. By adding a first heat exchanger, a second heat exchanger, and a third heat exchanger, different fractions of the main distillation column are used as heating media to preheat the tar, fully recovering the waste heat in the tar distillation process and cooling the different fractions, reducing the energy consumption required for subsequent heating, thereby reducing production costs.

[0005] The specific technical solution adopted in this utility model is as follows:

[0006] A tar distillation system includes a tar storage tank, a main distillation column, and a dehydration column. The main distillation column has, from top to bottom, a phenol oil output end, a mixed component output end, a heavy wash oil output end, and a soft asphalt output end. The output end of the tar storage tank is connected to the feed input end of the dehydration column, and the liquid phase output end of the dehydration column is connected to the feed input end of the main distillation column. A first heat exchanger, a second heat exchanger, and a third heat exchanger are also provided between the tar storage tank and the dehydration column. The high-temperature side input ends of the first, second, and third heat exchangers are respectively connected to the phenol oil output end, the mixed component output end, and the heavy wash oil output end of the main distillation column. The tar in the tar storage tank undergoes heat exchange sequentially through the low-temperature sides of the first, second, and third heat exchangers and flows into the dehydration column.

[0007] The high-temperature output end of the first heat exchanger is connected to the input end of the main column reflux tank via a phenol oil cooler. The reflux end of the main column reflux tank is connected to the phenol oil reflux end located at the top of the distillation main column via a main column reflux pump. The output end of the main column reflux tank is connected to the unwashed naphthalene oil tank.

[0008] The high-temperature output end of the second heat exchanger is connected to the input end of the unwashed naphthalene oil tank via a mixed component cooler.

[0009] The high-temperature output end of the third heat exchanger is connected to the input end of the heavy wash oil storage tank via a wash oil cooler.

[0010] The soft asphalt output end of the main distillation tower is connected to the input end of the main tower heater via a main tower extraction pump. The reflux end of the main tower heater is connected to the soft asphalt reflux end located at the bottom of the main distillation tower. The output end of the main tower heater is connected to the input end of the asphalt buffer tank.

[0011] The liquid phase output end of the dehydration tower is connected to the input end of the dehydration tower heater via the dehydration tower output pump, and the output end of the dehydration tower heater is connected to the raw material input end of the distillation main tower.

[0012] The liquid phase output end of the dehydration tower is connected to the input end of the reboiler via a circulating pump, and the output end of the reboiler is connected to the dehydrated tar reflux end located at the bottom of the dehydration tower.

[0013] The gas phase output end of the dehydration tower at the top is connected to the input end of the separator via a benzene fraction air cooler and a benzene fraction cooler in sequence. The water phase output end of the separator is connected to the phenol water tank, and the oil phase output end of the separator is connected to the benzene fraction tank. The reflux end of the benzene fraction tank is connected to the benzene fraction reflux end at the top of the dehydration tower via a dehydration tower reflux pump. The output end of the benzene fraction tank is connected to the input end of the crude benzene storage tank.

[0014] The beneficial effects of this utility model are:

[0015] This invention includes a first heat exchanger, a second heat exchanger, and a third heat exchanger. Since the phenolic oil, mixed fractions, and heavy wash oil produced by the distillation main column contain a large amount of heat, and these components need to be cooled before entering the next stage of the process, the first, second, and third heat exchangers are provided. By using different fractions from the distillation main column as heating media to preheat the tar, the residual heat from the tar distillation process is fully recovered, and different fractions are cooled, reducing the energy consumption required for subsequent heating and thus lowering production costs. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0018] Specific implementation examples Figure 1As shown, this utility model provides a tar distillation system, including a tar storage tank, a main distillation column, and a dehydration column. The main distillation column is provided with a phenol oil output end, a mixed component output end, a heavy wash oil output end, and a soft asphalt output end from top to bottom. The output end of the tar storage tank is connected to the raw material input end of the dehydration column, and the liquid phase output end of the dehydration column is connected to the raw material input end of the main distillation column. A first heat exchanger, a second heat exchanger, and a third heat exchanger are also provided between the tar storage tank and the dehydration column. The high-temperature side input ends of the first heat exchanger, the second heat exchanger, and the third heat exchanger are respectively connected to the phenol oil output end, the mixed component output end, and the heavy wash oil output end of the main distillation column. The tar in the tar storage tank undergoes heat exchange through the low-temperature side of the first heat exchanger, the second heat exchanger, and the third heat exchanger and flows into the dehydration column.

[0019] Current tar distillation processes do not fully recover the residual heat of the distillate during dehydration and fractionation. The heat released when high-temperature fractions such as phenolic oil, mixed fractions, and heavy wash oil are directly cooled is not effectively utilized, resulting in the system requiring additional energy to heat the feedstock tar, leading to high energy consumption.

[0020] This invention includes a first heat exchanger, a second heat exchanger, and a third heat exchanger. The extraction temperature of the phenolic oil is approximately 116°C, the extraction temperature of the mixed component is approximately 182°C, and the extraction temperature of the heavy wash oil is approximately 210°C. The dehydrated and deslag-removed tar from the tar storage is pumped out by the raw material tar pump, and after being heated by the first, second, and third heat exchangers to approximately 104°C, it enters the dehydration tower.

[0021] Since the phenolic oil, mixed fractions, and heavy wash oil produced by the main distillation column contain a large amount of heat, and these products need to be cooled before entering the next stage of the process, a heat exchanger is installed. By using different fractions from the main distillation column as heating media to preheat the tar, the residual heat from the tar distillation process is fully recovered, and different fractions are cooled, reducing the energy consumption required for subsequent heating and thus lowering production costs.

[0022] The high-temperature output end of the first heat exchanger is connected to the input end of the main column reflux tank via a phenol oil cooler. The reflux end of the main column reflux tank is connected to the phenol oil reflux end located at the top of the distillation main column via a main column reflux pump. The output end of the main column reflux tank is connected to the unwashed naphthalene oil tank. Most of the phenol oil in the main column reflux tank is sent as reflux liquid to the phenol oil reflux end of the distillation main column, and the remainder is sent to the unwashed naphthalene oil tank. Water generated by the phenol oil cooler during the cooling process flows into the phenol water tank.

[0023] The high-temperature output end of the second heat exchanger is connected to the input end of the unwashed naphthalene oil tank via a mixture cooler. The mixture is cooled to 90°C by the second heat exchanger and the mixture cooler before being sent to the unwashed naphthalene oil tank.

[0024] The high-temperature output end of the third heat exchanger is connected to the input end of the heavy wash oil storage tank via a wash oil cooler. The heavy wash oil is heated to 130°C by the third heat exchanger, and then cooled with warm water by the wash oil cooler before being sent into the heavy wash oil storage tank.

[0025] The soft asphalt output end of the main distillation column is connected to the input end of the main column heater via a main column extraction pump. The reflux end of the main column heater is connected to the soft asphalt reflux end located at the bottom of the main distillation column, and the output end of the main column heater is connected to the input end of the asphalt buffer tank. The temperature at the bottom of the main distillation column is approximately 292°C. After the soft asphalt at the bottom of the main distillation column is heated to 325°C by the main column heater, a portion is returned to the main column for further fractionation, while the other portion is sent to the asphalt buffer tank, awaiting entry into the modified asphalt unit for modification.

[0026] The liquid phase output end of the dehydration tower is connected to the input end of the dehydration tower heater via a dehydration tower output pump. The output end of the dehydration tower heater is connected to the raw material input end of the main distillation tower. The anhydrous tar collected from the liquid phase output end of the dehydration tower is approximately 191°C, which is relatively low. Therefore, it needs to be heated to 260°C in the dehydration tower heater before entering the lower part of the main distillation tower.

[0027] The liquid phase output of the dehydration tower is connected to the input of the reboiler via a circulating pump, and the output of the reboiler is connected to the dehydrated tar reflux end located at the bottom of the dehydration tower. By further dehydrating the tar with the circulating pump, the water content of the tar can be reduced, thereby improving the quality of the subsequently produced fraction.

[0028] The gas phase output end of the dehydration tower at the top is connected to the input end of the separator via a benzene fraction air cooler and a benzene fraction cooler in sequence. The water phase output end of the separator is connected to the phenol water tank, and the oil phase output end of the separator is connected to the benzene fraction tank. The reflux end of the benzene fraction tank is connected to the benzene fraction reflux end at the top of the dehydration tower via a dehydration tower reflux pump. The output end of the benzene fraction tank is connected to the input end of the crude benzene storage tank. The benzene, toluene, and water vapor escaping from the top of the dehydration tower are first cooled to 60°C by a benzene air cooler, and then cooled to 40°C by a benzene cooler, which reduces the energy consumed by the benzene cooler. The benzene, toluene, and water enter the separator for separation. The separated benzene enters the benzene tank, and most of it is sent to the top of the dehydration tower by the dehydration tower reflux pump as reflux to control the top temperature. The remaining benzene is pumped to the crude benzene storage tank by the benzene extract pump, while the separated water flows into the phenol water tank.

Claims

1. A tar distillation system, comprising a tar storage tank, a main distillation column, and a dehydration column, wherein the main distillation column is provided with a phenol oil output end, a mixed component output end, a heavy wash oil output end, and a soft asphalt output end from top to bottom; the output end of the tar storage tank is connected to the feed input end of the dehydration column, and the liquid phase output end of the dehydration column is connected to the feed input end of the main distillation column, characterized in that, A first heat exchanger, a second heat exchanger, and a third heat exchanger are also provided between the tar storage tank and the dehydration tower. The high-temperature input ends of the first heat exchanger, the second heat exchanger, and the third heat exchanger are respectively connected to the phenol oil output end, the mixed part output end, and the heavy wash oil output end of the main distillation tower. The tar in the tar storage tank passes through the low-temperature sides of the first heat exchanger, the second heat exchanger, and the third heat exchanger in sequence for heat exchange and flows into the dehydration tower.

2. The tar distillation system according to claim 1, characterized in that, The high-temperature output end of the first heat exchanger is connected to the input end of the main column reflux tank via a phenol oil cooler. The reflux end of the main column reflux tank is connected to the phenol oil reflux end located at the top of the distillation main column via a main column reflux pump. The output end of the main column reflux tank is connected to the unwashed naphthalene oil tank.

3. The tar distillation system according to claim 2, characterized in that, The high-temperature output end of the second heat exchanger is connected to the input end of the unwashed naphthalene oil tank via a mixed component cooler.

4. The tar distillation system according to claim 1, characterized in that, The high-temperature output end of the third heat exchanger is connected to the input end of the heavy wash oil storage tank via a wash oil cooler.

5. The tar distillation system according to claim 1, characterized in that, The soft asphalt output end of the main distillation tower is connected to the input end of the main tower heater via a main tower extraction pump. The reflux end of the main tower heater is connected to the soft asphalt reflux end located at the bottom of the main distillation tower. The output end of the main tower heater is connected to the input end of the asphalt buffer tank.

6. The tar distillation system according to claim 1, characterized in that, The liquid phase output end of the dehydration tower is connected to the input end of the dehydration tower heater via the dehydration tower output pump, and the output end of the dehydration tower heater is connected to the raw material input end of the distillation main tower.

7. A tar distillation system according to claim 1, characterized in that, The liquid phase output end of the dehydration tower is connected to the input end of the reboiler via a circulating pump, and the output end of the reboiler is connected to the dehydrated tar reflux end located at the bottom of the dehydration tower.

8. The tar distillation system according to claim 1, characterized in that, The gas phase output end of the dehydration tower at the top is connected to the input end of the separator via a benzene fraction air cooler and a benzene fraction cooler in sequence. The water phase output end of the separator is connected to the phenol water tank, and the oil phase output end of the separator is connected to the benzene fraction tank. The reflux end of the benzene fraction tank is connected to the benzene fraction reflux end at the top of the dehydration tower via a dehydration tower reflux pump. The output end of the benzene fraction tank is connected to the input end of the crude benzene storage tank.

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