Negative pressure crude benzene distillation system adopting tubular furnace for heating

Abstract

The utility model relates to a negative-pressure crude benzene distillation system adopting a tubular furnace for heating. The negative-pressure crude benzene distillation system comprises a debenzolization tower, the tubular furnace and a crude benzene condensing, cooling and separating integrated device, the debenzolization tower is sequentially provided with a rectifying section, a stripping section, a storage tank section and a regeneration section from top to bottom; the crude benzene condensing, cooling and separating integrated device comprises a heat exchange tower and a separating tank; a low-temperature water heat exchanger is arranged at the lower part of the heat exchange tower; a crude benzene collecting section, an oil-gas-water separating section and a water collecting section are arranged in the separating tank; a first heating section and a second heating section are arranged in the tubular furnace. Compared with an existing negative-pressure crude benzene distillation process system, the negative-pressure crude benzene distillation process system has the remarkable advantages that the tail gas output is low, the tail gas is not discharged, the tube furnace operation temperature is low, the washing oil consumption is small, no additional separated water is generated, the one-time investment is low, and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to coking product recovery technical field especially relates to a kind of negative pressure crude benzol distillation system of tubular furnace heating. BACKGROUND

[0002] There are two methods of crude benzol distillation process in coking industry, namely positive pressure crude benzol distillation (also known as atmospheric crude benzol distillation) and negative pressure crude benzol distillation. The positive pressure crude benzol distillation process uses superheated steam to distill at 30-50 kPa pressure. The disadvantage of this process is that it consumes a large amount of energy while producing a large amount of crude benzol separation water which is difficult to handle. The negative pressure crude benzol distillation process uses vacuum distillation. It uses the principle of reducing liquid surface pressure to reduce liquid boiling point. It uses a vacuum device to extract non-condensable gas at the top of the tower to reduce the liquid surface pressure in the tower to achieve a negative pressure state, thereby saving heat for distillation and improving separation efficiency. It uses circulating hot lean oil to provide heat. Therefore, compared with the positive pressure crude benzol distillation method, it can greatly reduce the generation of waste water and greatly reduce the operating cost.

[0003] Currently, there are mainly three processes for negative pressure crude benzol distillation.

[0004] The first one is a negative pressure crude benzol distillation process that uses lean oil at the bottom of the distillation column to heat in a tubular furnace as a heat source. The process heat is brought into the benzene removal tower by the lean oil heated by gas in the tubular furnace. The upward airflow in the benzene removal tower is mainly crude benzol gas and part of the vaporized wash oil. The advantage of this process is that no additional crude benzol separation water is produced, and the self-produced coke oven gas of the coking plant can be used as a heat source. The disadvantage is that a large amount of tail gas is produced after the gas is burned in the tubular furnace, and it is difficult to meet the environmental protection standard. The construction of an additional tail gas treatment system leads to increased investment. In addition, this process uses indirect heating of gas, and the wall temperature of the heat exchange pipe is high, resulting in a large amount of wash oil slag and high consumption.

[0005] The second one is a negative pressure crude benzol distillation process that uses superheated steam as a direct heat source. The process heat is brought into the benzene removal tower by superheated steam. The upward airflow in the benzene removal tower is crude benzol gas, part of the vaporized gasoline, and superheated steam. The advantage of this process is that the operating temperature of the benzene removal tower is low, and the wash oil consumption is low. The disadvantage is that crude benzol separation water is produced at the same time as the rich oil is removed, increasing the production load of the subsequent waste water treatment.

[0006] The third one is a negative pressure crude benzol distillation process using a reboiler. It uses steam to heat the circulating wash oil at the bottom of the tower to provide heat for the benzene removal tower. The upward airflow in the benzene removal tower is mainly crude benzol gas and part of the vaporized wash oil. The advantage of this process is that there is neither combustion tail gas nor additional crude benzol separation water. The disadvantage is that the consumption of heating steam is large, and the operating cost is high.

[0007] In summary, the crude benzol distillation process at the present stage mainly has three problems of difficult to reach the environmental protection index requirement, large construction investment and high operation cost. In addition, the crude benzol distillation process has the following common characteristics:

[0008] 1) Because of the process requirement, a civil frame is needed to be arranged outside the benzole tower for installing the gas-liquid separator and the oil-water separator, which has large one-time investment and long construction period;

[0009] 2) The tower internals of the benzole tower adopt the tray, or the stripping section adopts the packing, and the rectification section adopts the tray. The packing has the advantages of reducing the tower height and the tower resistance, and the disadvantage is that the naphthalene extraction line in the rectification section is not easy to set. If the tower internals of the benzole tower all adopt the packing and still can extract the naphthalene from the side line, the one-time investment of the equipment and the field installation time can be reduced. SUMMARY

[0010] The utility model provides a kind of negative pressure crude benzol distillation system heated with tubular furnace, compared with existing negative pressure crude benzol distillation process system, with low tail gas production and tail gas is not discharged, tubular furnace pipe operating temperature is low, washing oil consumption is small, no additional separation water is produced, one-time investment is low and other remarkable advantages.

[0011] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0012] A kind of negative pressure crude benzol distillation system heated with tubular furnace, including benzole tower, tubular furnace and crude benzol condensation cooling separation integrated device;The benzole tower is sequentially provided with rectification section, stripping section, storage tank section and regeneration section from top to bottom;Wherein rectification section and stripping section are both provided with packing;The top of rectification section is provided with reflux crude benzol distributor, the top of stripping section is provided with rich oil distributor, the top of storage tank section is provided with hot lean oil distributor;Regeneration section is provided with heater;Storage tank section and regeneration section are connected by circulating lean oil pipeline;The crude benzol condensation cooling separation integrated device includes heat exchange tower and separation tank;The upper portion of heat exchange tower is provided with circulating water heat exchanger, and the lower portion is provided with low-temperature water heat exchanger;Separation tank is provided with crude benzol collection section, oil-gas-water separation section and water collection section;The bottom of heat exchange tower is communicated with the top of oil-gas-water separation section;Low-temperature water-non-condensable gas heat exchanger is arranged in the separation tank above oil-gas-water separation section;The tubular furnace is provided with heating section one and heating section two;

[0013] The rich oil inlet of the rich oil distributor is connected with the rich oil outlet of the lean-rich oil heat exchanger, and the rich oil inlet of the lean-rich oil heat exchanger is connected with the rich oil outlet pipeline of the benzene washing unit; one side of the bottom of the storage section of the benzene stripping tower is provided with a lean oil outlet which is connected with the lean oil inlet of the lean-rich oil heat exchanger through a lean oil pump; the other side of the bottom of the storage section is provided with a lean oil outlet two which is connected with the heating section one and the heating section two of the tubular furnace through a lean oil circulating pump; the hot lean oil outlet of the heating section one is connected with the hot lean oil inlet of the regeneration section and the hot lean oil distributor of the storage section through a hot lean oil pipeline; the hot lean oil outlet of the heating section two is connected with the heater inlet of the regeneration section, and the heater outlet is connected with the hot lean oil pipeline led out from the heating section one.

[0014] One side of the upper part of the rectification section is provided with a naphthalene oil outlet which is connected with a naphthalene oil pipeline;

[0015] The crude benzene vapor outlet at the top of the benzene stripping tower is connected with the crude benzene vapor inlet at the top of the crude benzene condensation-cooling separation integrated device; the crude benzene collection section of the crude benzene condensation-cooling separation integrated device is provided with a crude benzene outlet which is connected with a crude benzene return pipeline and a crude benzene product delivery pipeline, and the crude benzene return pipeline is connected with the crude benzene inlet of the reflux crude benzene distributor; the non-condensable gas outlet at the top of the oil-gas-water separation section of the crude benzene condensation-cooling separation integrated device is connected with the benzene washing unit through a vacuum pump, and the water collection section is provided with a separation water outlet which is connected with the coal gas final cooling unit through a separation water pump.

[0016] The separation tank of the crude benzene condensation-cooling separation integrated device is a horizontal tank, and a first partition plate, a second partition plate and a third partition plate are arranged in the separation tank in the longitudinal direction, wherein the top surface of the second partition plate is higher than the top surface of the first partition plate, the top surface of the first partition plate is higher than the top surface of the third partition plate, and the bottom surface of the second partition plate is spaced apart from the bottom surface of the separation tank by a distance; the space between the first partition plate and the second partition plate is an oil-gas-water separation section, the internal space of the separation tank on the outside of the first partition plate is a crude benzene collection section, and the internal space of the separation tank on the outside of the third partition plate is a water collection section.

[0017] The residue tank is a horizontal tank, and an inner partition plate is arranged in the residue tank; the top of the residue tank is provided with a naphthalene oil inlet and a naphthalene oil outlet on the two sides of the inner partition plate, the naphthalene oil inlet is connected with a naphthalene oil pipeline, and a naphthalene oil inlet pipe is arranged at the naphthalene oil inlet and vertically extends downward to the bottom of the residue tank; the top surface of the inner partition plate is higher than the opening height of the bottom of the naphthalene oil inlet pipe; the naphthalene oil outlet of the residue tank is connected with the return naphthalene oil inlet at the top of the benzene stripping tower through a naphthalene oil return pipeline; the lower part of the residue tank on the side close to the naphthalene oil outlet is provided with a naphthalene oil delivery port which is connected with the inlet of a residue pump; the bottom of the regeneration section of the benzene stripping tower is provided with a washing oil residue outlet which is connected with the inlet of the residue pump, and the outlet of the residue pump is connected with a tar storage tank of the oil storage unit.

[0018] The lean oil outlet of the lean-rich oil heat exchanger is connected with the benzene washing unit through a lean oil pipeline, and a lean oil cooler and a lean oil cryogenic cooler are arranged on the lean oil pipeline in sequence.

[0019] The top of the tubular furnace is provided with a flue gas outlet, and the bottom is provided with a burner, which is provided with a clean gas inlet and a combustion gas inlet.

[0020] Compared with the prior art, the utility model has the advantages of:

[0021] 1) Good environmental protection effect: compared with the negative pressure crude benzene distillation process which uses the distillation tower bottom lean oil as a heat source in the tubular furnace, the process generates less tubular furnace waste gas, and all the waste gas is sent to the desulfurization and denitrification device for treatment, so that no waste gas is discharged; compared with the negative pressure crude benzene distillation process which uses superheated steam as a direct heat source, the utility model does not generate additional crude benzene separation water, thereby reducing the wastewater discharge amount.

[0022] 2) Low construction cost: the utility model integrates the crude benzene condensing cooler, the gas-liquid separator, the non-condensing steam cooler and the oil-water separator in the conventional crude benzene distillation system into one, that is, a crude benzene condensing and cooling separation integrated device, which can realize crude benzene steam condensing and cooling, gas-liquid separation, oil-water separation, crude benzene reflux buffering and non-condensing steam condensing and cooling in one device; the device is compact in structure and small in size, and the equipment and land investment are obviously reduced.

[0023] In the previous design, the gas-liquid separator and the oil-water separator are two independent devices, in order to maintain the vacuum degree of the gas-liquid separator, the gas-liquid separator and the oil-water separator are designed at different elevations and a certain elevation difference is maintained; when this design is adopted, a mounting frame must be arranged to place the two devices; the utility model integrates the two, and the integrated crude benzene condensing and cooling separation integrated device can be directly placed on the ground, thereby canceling the mounting frame and obviously reducing the initial investment in civil construction.

[0024] The rectification section and the stripping section of the debenzolization tower adopt the packing instead of the tray as the mass transfer surface, so that the height of the debenzolization tower is obviously reduced and the initial investment in equipment is saved; the rectification section is provided with a side line take-off device, and a liquid breaking disc and a redistribution device are not needed, and the naphthalene component in the circulating oil can be taken off.

[0025] 3) Low running cost: the utility model does not use steam as a heating source of the debenzolization tower, but uses the self-produced coal gas of the coking plant as a heat source, so that the running cost is low.

[0026] The tubular furnace uses the reaction heat of the combustion of coal gas and air as a heat source, a part of the waste gas after combustion is sent to the desulfurization and denitrification device for purification treatment, and a part is returned to the front of the air fan, so that the amount of waste gas discharged is effectively reduced, the coal gas consumption is reduced, the wall temperature of the furnace tube is reduced, the deterioration speed of the washing oil is slowed down, and the running cost is low.

[0027] 4) Good benzene removal effect in rich oil and low naphthalene content in lean oil: In order to reduce the resistance of the benzene removal tower, the rectification section and stripping section of the benzene removal tower described in this utility model use packing as the mass transfer surface instead of trays, which greatly reduces the resistance of the benzene removal tower and significantly increases the benzene removal efficiency of rich oil; the rectification section of the benzene removal tower uses packing as the mass transfer surface and is equipped with a side stream sampling device, so that the naphthalene component in the circulating oil can be sampled without the need for a liquid cut-off plate and a redistribution device. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a negative pressure crude benzene distillation system using a tubular furnace for heating, as described in this utility model.

[0029] In the diagram: 1. Benzene removal tower 2. Integrated unit for crude oil pump condensation, cooling, and separation 3. Tubular furnace 4. Residue tank 5. Benzene pump 6. Lean oil circulating pump 7. Lean oil pump 8. Residue pump 9. Separation water pump 10. Vacuum pump 11. Air fan 12. Lean oil cryocooler 13. Lean oil cooler 14. Lean and rich oil heat exchanger Detailed Implementation

[0030] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings:

[0031] like Figure 1 As shown, the present invention discloses a negative pressure crude benzene distillation system using a tubular furnace for heating, comprising a benzene removal tower 1, a tubular furnace 3, and a crude benzene condensation and cooling separation integrated device 2. The benzene removal tower 1 is provided with a rectification section, a stripping section, a storage tank section, and a regeneration section from top to bottom. The rectification section and the stripping section are both filled with packing material. A reflux crude benzene distributor is provided at the top of the rectification section, a rich oil distributor is provided at the top of the stripping section, and a hot lean oil distributor is provided at the top of the storage tank section. A heater is provided in the regeneration section. The storage tank section and the regeneration section are connected by a circulating lean oil pipeline. The crude benzene condensation and cooling separation integrated device 2 includes a heat exchange tower and a separation tank. A circulating water heat exchanger is provided at the top of the heat exchange tower, and a low-temperature water heat exchanger is provided at the bottom. The separation tank is provided with a crude benzene collection section, an oil-gas-water separation section, and a water collection section. The bottom of the heat exchange tower is connected to the top of the oil-gas-water separation section. A low-temperature water-non-condensable gas heat exchanger is provided in the separation tank above the oil-gas-water separation section. The tubular furnace is provided with a first heating section and a second heating section.

[0032] The rich oil inlet of the rich oil distributor is connected with the rich oil outlet of the lean-rich oil heat exchanger 14, and the rich oil inlet of the lean-rich oil heat exchanger 14 is connected with the rich oil outlet pipeline of the benzene washing unit; one side of the bottom of the storage tank section of the benzene stripping tower 1 is provided with a lean oil outlet, and the lean oil outlet is connected with the lean oil inlet of the lean-rich oil heat exchanger 14 through a lean oil pump 7; the other side of the bottom of the storage tank section is provided with a lean oil outlet two, and the lean oil outlet two is connected with the heating section one and the heating section two of the tubular furnace 3 through a lean oil circulating pump 6; the hot lean oil outlet of the heating section one is connected with the hot lean oil inlet of the regeneration section and the hot lean oil distributor of the storage tank section through a hot lean oil pipeline; the hot lean oil outlet of the heating section two is connected with the heater inlet of the regeneration section, and the heater outlet is connected with the hot lean oil pipeline led out from the heating section one.

[0033] One side of the upper part of the rectification section is provided with a naphthalene oil outlet, and the naphthalene oil outlet is connected with the residual tank 4 through a naphthalene oil outlet pipeline.

[0034] The crude benzene vapor outlet at the top of the benzene stripping tower 1 is connected with the crude benzene vapor inlet at the top of the crude benzene condensation cooling separation integrated device 2; the crude benzene collection section of the crude benzene condensation cooling separation integrated device 2 is provided with a crude benzene outlet connected with a crude benzene return pipeline and a crude benzene product delivery pipeline, and the crude benzene return pipeline is connected with the crude benzene inlet of the reflux crude benzene distributor; the non-condensable gas outlet at the top of the oil-gas-water separation section of the crude benzene condensation cooling separation integrated device 2 is connected with the benzene washing unit through a vacuum pump 10, and the water collection section is provided with a separated water outlet connected with the coal gas final cooling unit through a separated water pump 9.

[0035] The separation tank of the crude benzene condensation cooling separation integrated device 2 is a horizontal tank, and a first partition plate, a second partition plate and a third partition plate are arranged in the separation tank in the longitudinal direction, wherein the top surface of the second partition plate is higher than the top surface of the first partition plate, the top surface of the first partition plate is higher than the top surface of the third partition plate, and the bottom surface of the second partition plate is spaced apart from the bottom surface of the separation tank by a distance; the space between the first partition plate and the second partition plate is an oil-gas-water separation section, the internal space of the separation tank on the outer side of the first partition plate is a crude benzene collection section, and the internal space of the separation tank on the outer side of the third partition plate is a water collection section.

[0036] The residual tank 4 is a horizontal tank, and an inner partition plate is arranged in the residual tank 4; the top of the residual tank 4 is provided with a naphthalene oil inlet and a naphthalene oil outlet on the two sides of the inner partition plate, the naphthalene oil inlet is connected with the naphthalene oil outlet pipeline, and a naphthalene oil inlet pipe is arranged at the naphthalene oil inlet and vertically extends downward to the bottom of the residual tank 4; the top surface of the inner partition plate is higher than the bottom opening height of the naphthalene oil inlet pipe; the naphthalene oil outlet of the residual tank 4 is connected with the return naphthalene oil inlet at the top of the benzene stripping tower 1 through a naphthalene oil return pipeline; the residual tank 4 is provided with a naphthalene oil delivery port at the lower part near the naphthalene oil outlet, and the naphthalene oil delivery port is connected with the inlet of a residual pump 8; the regeneration section of the benzene stripping tower 1 is provided with a washing oil residual outlet connected with the inlet of the residual pump 8, and the outlet of the residual pump 8 is connected with a tar storage tank of an oil storage unit.

[0037] The lean oil outlet of the lean-rich oil heat exchanger 14 is connected with the benzene washing unit through a lean oil pipeline, and a lean oil cooler 13 and a lean oil cryogenic cooler 12 are arranged on the lean oil pipeline in sequence.

[0038] The top of the tubular furnace 3 is provided with a flue gas outlet, and the bottom is provided with a burner, which is provided with a clean gas inlet and a combustion gas inlet connected with the outlet of the air blower 11 through a combustion gas pipeline; the flue gas inlet of the tubular furnace 3 is connected with the flue gas inlet of the desulfurization and denitrification device through a flue gas pipeline one, and is connected with the inlet of the air blower 11 through a flue gas pipeline two.

[0039] The negative pressure crude benzene distillation system heated by the tubular furnace utilizes one tubular furnace 3 to complete the function of heating two circulating washing oils, one of which is used as a heat source for crude benzene distillation, and the other is used as a heat source for washing oil regeneration. One (set) vacuum pump is used to maintain the vacuum degree of the crude benzene distillation system and the washing oil regeneration system.

[0040] Part of the flue gas generated by the tubular furnace 3 is sent to the desulfurization and denitrification device, and part is returned to before the air blower 11, which can effectively reduce the amount of exhaust gas, reduce the consumption of coal gas, reduce the wall temperature of the furnace tube, and slow down the deterioration speed of the washing oil.

[0041] The crude benzene condensation cooling separation integrated device 2 is placed on the ground without the need of an additional installation frame.

[0042] In order to reduce the resistance of the benzene removal tower 1, the rectification section and the stripping section in the benzene removal tower 1 both use packing as the mass transfer surface, which greatly reduces the resistance of the benzene removal tower, significantly increases the rich oil benzene removal efficiency, and obviously reduces the height of the benzene removal tower.

[0043] The benzene removal tower 1 uses packing as the mass transfer surface in the rectification section, and is provided with a side line extraction device, without the need of a liquid breaking disc and a redistribution device, so that the naphthalene component in the circulating oil can be extracted, the naphthalene content of the lean oil can be reduced, and the naphthalene content of the coal gas after washing benzene can be reduced.

[0044] In order to ensure the quality of the circulating washing oil, a small amount of hot lean oil is introduced from the circulating hot lean oil and sent to the regeneration section of the benzene removal tower 1, which is heated by the heater using the hot lean oil as the heat source, and the oil vapor mixture is introduced into the bottom of the benzene removal tower 1 as a distillation heat source.

[0045] The process of the negative pressure crude benzene distillation system heated by the tubular furnace according to the utility model is as follows:

[0046] 1) The benzene-stripping column 1 is provided with rectification section, stripping section, storage section and regeneration section from top to bottom in turn; the rectification section and the stripping section are both provided with packing; the regeneration section is provided with heater; the rich oil from the benzene washing unit is exchanged with the hot lean oil discharged from the bottom of the benzene-stripping column 1 by the lean oil heat exchanger 14, and then enters the stripping section of the benzene-stripping column 1 for distillation; a part of the hot lean oil from the bottom of the benzene-stripping column 1 is pumped out by the lean oil pump 7, and is cooled by the lean oil heat exchanger 14, lean oil cooler 13 and lean oil deep cooler 12 in turn, and then is sent to the benzene washing unit;

[0047] 2) Another part of the hot lean oil from the bottom of the benzene-stripping column 1 is pumped out by the lean oil circulating pump 6, and is sent to the tubular furnace 3 in two parts for heating; most of the lean oil is heated and then enters the storage section of the benzene-stripping column 1 for flash evaporation, and is used as heat source for distillation; a small part of the lean oil is heated and then is sent to the heater in the regeneration section at the bottom of the benzene-stripping column 1, and is used as heat source for washing oil regeneration;

[0048] 3) The crude benzene vapor extracted from the top of the benzene-stripping column 1 enters the crude benzene condensation cooling separation integrated device 2, exchanges with circulating water and low-temperature water in turn, and then enters the lower separation tank; the separation tank is provided with crude benzene collection section, oil-gas-water separation section and water collection section; the crude benzene after heat exchange and condensation directly enters the oil-gas-water separation section, and the separation of crude benzene, non-condensable gas and water is realized by standing; the separated non-condensable gas is further exchanged with low-temperature water for deep cooling, and then is pumped out by the vacuum pump 10 and sent to the benzene washing unit; the separated crude benzene overflows into the crude benzene collection section, and a part of it is pumped out by the benzene pump 5 and sent to the top of the benzene-stripping column 1 as reflux; another part of it is sent to the crude benzene storage tank of the oil storage unit as crude benzene product; the separated water overflows into the water collection section, and is pumped out by the separation water pump 9 and sent to the coal gas final cooling unit;

[0049] 4) The naphthalene oil fraction is introduced from the side line of the rectification section of the benzene-stripping column 1, and enters the residue tank 4, and is sent to the tar storage tank of the oil storage unit by the residue pump 8 periodically;

[0050] 5) A small amount of hot lean oil is introduced from the circulating heating oil, and is sent to the regeneration section at the lower part of the benzene-stripping column 1, and is heated by the heater, and the evaporated oil-gas mixture is sent to the bottom of the benzene-stripping column 1 as heat source;

[0051] 6) The tubular furnace 3 uses the reaction heat of combustion of coal gas and air as heat source; a part of the waste gas after combustion is sent to the desulfurization and denitrification device for purification treatment, and another part is returned to the air pipeline upstream of the air fan 11, mixed with the newly entered air, and then is sent to the tubular furnace 3 as combustion-supporting gas.

[0052] The above is only the preferred specific implementation manner of the present application, but the protection scope of the present application is not limited to this; any skilled person in the art, according to the technical scheme and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, should be covered within the protection scope of the present application.

Claims

1. A negative pressure crude benzol distillation system using a tubular furnace heating, characterized by, The application relates to a benzene removal tower, a tubular furnace and a crude benzene condensation-cooling separation integrated device; the benzene removal tower is sequentially provided with a rectification section, a stripping section, a storage section and a regeneration section from top to bottom; the rectification section and the stripping section are both provided with fillers; a reflux crude benzene distributor is arranged at the top of the rectification section, a rich oil distributor is arranged at the top of the stripping section, and a hot lean oil distributor is arranged at the top of the storage section; the regeneration section is provided with a heater; the storage section and the regeneration section are connected through a circulating lean oil pipeline; the crude benzene condensation-cooling separation integrated device comprises a heat exchange tower and a separation tank; the upper part of the heat exchange tower is provided with a circulating water heat exchanger, and the lower part is provided with a low-temperature water heat exchanger; the separation tank is provided with a crude benzene collecting section, an oil-gas-water separation section and a water collecting section; the bottom of the heat exchange tower is communicated with the top of the oil-gas-water separation section; a low-temperature water-non-condensable gas heat exchanger is arranged in the separation tank above the oil-gas-water separation section; the tubular furnace is provided with a heating first section and a heating second section. The rich oil inlet of the rich oil distributor is connected with the rich oil outlet of a lean-rich oil heat exchanger, the rich oil inlet of the lean-rich oil heat exchanger is connected with the rich oil outlet pipeline of a benzene washing unit; one side of the bottom of the storage section of the benzene removal tower is provided with a lean oil outlet one which is connected with the lean oil inlet of the lean-rich oil heat exchanger through a lean oil pump; the other side of the bottom of the storage section is provided with a lean oil outlet two which is connected with the heating first section and the heating second section of the tubular furnace through a lean oil circulating pump; the hot lean oil outlet of the heating first section is connected with the hot lean oil inlet of the regeneration section and the hot lean oil distributor of the storage section through a hot lean oil pipeline; the hot lean oil outlet of the heating second section is connected with the heater inlet of the regeneration section, and the heater outlet is connected with the hot lean oil pipeline led out from the heating first section. One side of the upper part of the rectification section is provided with a naphthalene oil collecting outlet which is connected with a residual tank through a naphthalene oil collecting pipeline. The crude benzene vapor outlet of the top of the benzene removal tower is connected with the crude benzene vapor inlet of the top of the crude benzene condensation-cooling separation integrated device; the crude benzene collecting section of the crude benzene condensation-cooling separation integrated device is provided with a crude benzene outlet which is connected with a crude benzene return pipeline and a crude benzene product delivery pipeline; the crude benzene return pipeline is connected with the crude benzene inlet of the reflux crude benzene distributor; the non-condensable gas outlet of the top of the oil-gas-water separation section of the crude benzene condensation-cooling separation integrated device is connected with a benzene washing unit through a vacuum pump; the water collecting section is provided with a separation water outlet which is connected with a coal gas final cooling unit through a separation water pump.

2. The negative pressure crude benzol distillation system heated by the tubular furnace according to claim 1, characterized in that, The separation tank of the crude benzene condensation-cooling separation integrated device is a horizontal tank, and a partition one, a partition two and a partition three are arranged in the separation tank along the longitudinal direction; the top surface of the partition two is higher than the top surface of the partition one, the top surface of the partition one is higher than the top surface of the partition three, and the bottom surface of the partition two is spaced apart from the bottom surface of the separation tank by a distance; the space between the partition one and the partition two is the oil-gas-water separation section, the internal space of the separation tank outside the partition one is the crude benzene collecting section, and the internal space of the separation tank outside the partition three is the water collecting section.

3. The negative pressure crude benzol distillation system heated by tubular furnace according to claim 1, characterized in that, The residue tank is a horizontal tank, and an inner partition plate is arranged in the residue tank. A naphthalene oil inlet and a naphthalene oil outlet are arranged at two sides of the inner partition plate at the top of the residue tank, the naphthalene oil inlet is connected with a naphthalene oil extraction pipeline, a naphthalene oil inlet pipe is arranged at the naphthalene oil inlet, and the naphthalene oil inlet pipe extends vertically downward to the bottom of the residue tank. The top surface of the inner partition plate is higher than the bottom opening height of the naphthalene oil inlet pipe. The naphthalene oil outlet of the residue tank is connected with a return naphthalene oil inlet at the top of a benzene stripping tower through a naphthalene oil return pipeline. A naphthalene oil delivery outlet is arranged at the lower part of the residue tank at the side close to the naphthalene oil outlet, and the naphthalene oil delivery outlet is connected with the inlet of a residue pump. A washing oil residue outlet is arranged at the bottom of the regeneration section of the benzene stripping tower, and the washing oil residue outlet is connected with the inlet of the residue pump. The outlet of the residue pump is connected with a tar storage tank of an oil storage unit.

4. The negative pressure crude benzol distillation system heated by tubular furnace according to claim 1, characterized in that, The lean oil outlet of the lean oil-rich oil heat exchanger is connected with a benzene washing unit through a lean oil pipeline, and a lean oil cooler and a lean oil cryogenic cooler are sequentially arranged on the lean oil pipeline.

5. The negative pressure crude benzol distillation system heated by tubular furnace according to claim 1, characterized in that, The top of the tubular furnace is provided with a flue gas outlet, and the bottom is provided with a burner. The burner is provided with a clean gas inlet and a combustion-supporting gas inlet. The combustion-supporting gas inlet is connected with the outlet of an air blower through a combustion-supporting gas pipeline. The flue gas inlet of the tubular furnace is connected with the flue gas inlet of a desulfurization and denitrification device through a flue gas pipeline one, and is connected with the inlet of an air blower through a flue gas pipeline two.

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