Coal chemical oil product fractionation heating system and method

Abstract

The application relates to a coal chemical oil product fractionation heating system and method, which comprises a dephenol tower system and a pressurized tower system, the dephenol tower system comprises a dephenol tower, a centrifugal machine, a phenol ammonia water tank, a raw material buffer tank, the raw material buffer tank is communicated with a dewatering tank, a multielement hydrocarbon raw material pipeline is further connected on a pipeline communicated between the two, and the dewatering tank is communicated with the dephenol tower; the top of the dephenol tower is communicated with a dephenol tower top reflux tank, the dephenol tower top reflux tank is communicated with a flare or fuel gas system, a phenol ammonia water tank and a light hydrocarbon tank area; the middle section of the dephenol tower is communicated with a reflux pipeline; the bottom of the dephenol tower is communicated with a bottom oil pipeline; the top of a vacuum tower is communicated with a vacuum tower top reflux tank and a flare or fuel gas system, the vacuum tower top reflux tank is communicated with a vacuum tower and a washing oil tank area; the middle section of the vacuum tower is communicated with a reflux pipeline; and the bottom of the vacuum tower is communicated with an asphalt tank area through an asphalt pipeline. The application greatly saves the use amount of low-pressure steam, reduces the discharge amount of sewage and reduces the operation cost.

Description

Technical Field

[0001] This application relates to a coal tar processing system and method, and more particularly to a coal chemical oil fractionation heating system and method. Background Technology

[0002] In existing technologies, the typical process for dephenolization of coal tar fractions in the coal tar processing industry involves heating the raw material in a furnace before it enters a dephenolization tower and undergoes steam stripping. Light hydrocarbons and phenolic oil are collected via a side stream. The heavy oil at the bottom of the tower is heated in a furnace and then enters a vacuum distillation tower for further steam stripping. Wash oil and anthracene oil are collected via a side stream, and coal tar pitch is collected at the bottom of the tower. All products are then stored in a tank farm. During this process, heavy aromatics and polycyclic aromatics from the gas-water separation unit are used as raw materials, and vacuum distillation is frequently used to separate light hydrocarbons, phenolic oil, wash oil, anthracene oil, and coal tar pitch. After the heavy aromatics and polycyclic aromatics are separated into light hydrocarbons and phenolic oil in the dephenolization tower, the wash oil and water in the reflux tank at the top of the vacuum distillation tower have very similar densities, making effective oil-water separation difficult.

[0003] Currently, the phenol removal process in all coal tar processing plants, both domestically and internationally, has not adequately addressed the problem of generating substantial amounts of wastewater. Therefore, there is an urgent need in this field to improve existing phenol removal processes, making new processes more suitable for coal tar processing and production, reducing the phenol content in wash oil, and decreasing the amount of phenol-containing wastewater discharged. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the purpose of this application is to propose a coal chemical oil fractionation heating system that can achieve a clear separation between phenolic oil and wash oil, reduce the content of phenolic oil components in wash oil, and reduce the discharge of phenol-containing wastewater; based on this purpose, another purpose of this application is to propose a coal chemical oil fractionation heating method.

[0005] The purpose of this application is achieved as follows: a coal chemical oil fractionation heating system, including a dephenolization tower system and a vacuum tower system. The dephenolization tower system includes a dephenolization tower, a centrifuge is installed at the front side of the feed end of the dephenolization tower, the aqueous phase outlet of the centrifuge is connected to a phenol-ammonia water tank, the oil phase outlet is connected to a raw material buffer tank, the discharge port of the raw material buffer tank is connected to the feed port of the dehydration tank, a multi-hydrocarbon raw material pipeline is also connected to the pipeline connecting the two, the gas phase outlet of the dehydration tank is connected to the top of the dephenolization tower, and the liquid phase outlet of the dehydration tank is connected to the middle and lower part of the dephenolization tower.

[0006] The gas phase outlet at the top of the dephenol removal tower is connected to the top reflux tank of the dephenol removal tower. The gas phase outlet of the top reflux tank of the dephenol removal tower is connected to the flare or fuel gas system. The liquid phase outlet of the top reflux tank of the dephenol removal tower is connected to the phenol ammonia water tank. The oil phase outlet of the top reflux tank of the dephenol removal tower is connected to the light hydrocarbon tank area.

[0007] The middle section of the dephenol removal tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the dephenol removal tower to form a cooling reflux pipeline, and the second outlet is connected to the tank area or crude phenol extraction unit.

[0008] The bottom of the dephenol removal tower is connected to a bottom oil pipeline, which is divided into two lines. The first line is connected to the feed inlet of the bottom heater of the dephenol removal tower, and the discharge outlet of the bottom heater of the dephenol removal tower is connected to the bottom of the dephenol removal tower. The second line is connected to the feed inlet of the vacuum feed heater, and the discharge outlet of the vacuum feed heater is connected to the bottom of the vacuum tower.

[0009] The top of the pressure reducing tower is connected to the pressure reducing tower top reflux tank. The gas phase outlet of the pressure reducing tower top reflux tank is connected to the flare or fuel gas system. One oil phase outlet of the pressure reducing tower top reflux tank is connected to the top of the pressure reducing tower, and the other is connected to the oil washing tank area.

[0010] The middle section of the pressure reducing tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the pressure reducing tower to form a cooling reflux pipeline, and the second outlet is connected to the anthracene oil tank area.

[0011] The bottom of the pressure relief tower is connected to the asphalt tank area via an asphalt pipeline.

[0012] The phenol-ammonia water tank is connected to the upstream coal gasification unit via a phenol-ammonia water pump.

[0013] The raw material buffer tank is connected to the feed inlet of the dehydration tank via the raw material feed pump, the oil / raw material heat exchanger in the middle section of the dephenolization tower, and the raw material heater.

[0014] The liquid phase outlet of the dehydration tank is connected to the lower part of the dephenolization tower via a feed oil booster pump, a heat exchanger for oil / feed oil in the middle section of the dephenolization tower, a heat exchanger for asphalt / feed oil, and a heat exchanger for oil / feed in the middle section of the vacuum tower.

[0015] The gas phase outlet at the top of the dephenolization tower is connected to the dephenolization tower top reflux tank via the dephenolization tower top water cooler. The gas phase outlet of the dephenolization tower top reflux tank is connected to the top vacuum system of the connecting tower and then connected to the flare or fuel gas system. The oil phase outlet of the dephenolization tower top reflux tank is connected to the light hydrocarbon tank area via the dephenolization tower top reflux pump.

[0016] The middle section of the dephenolization tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the oil / raw material heat exchanger in the middle section of the dephenolization tower, forming a cooling reflux pipeline. The second outlet is connected to the tank area or crude phenol extraction unit via a phenol oil water cooler.

[0017] The bottom of the dephenol removal tower is connected to a bottom oil pipeline. After passing through the bottom heavy oil pump of the dephenol removal tower, the bottom oil pipeline is divided into two paths. The first path is connected to the feed inlet of the bottom heater of the dephenol removal tower, and the discharge outlet of the bottom heater of the dephenol removal tower is connected to the bottom of the dephenol removal tower. The second path is connected to the feed inlet of the vacuum feed heater, and the discharge outlet of the vacuum feed heater is connected to the bottom of the vacuum tower.

[0018] The top of the pressure reducing tower is connected to the feed inlet of the pressure reducing tower top reflux tank via the pressure reducing tower top air cooler. The gas phase outlet of the pressure reducing tower top reflux tank is connected to the flare or fuel gas system via the pressure reducing tower top water cooler and the tower top evacuation system. The oil phase outlet of the pressure reducing tower top reflux tank is connected to the top of the pressure reducing tower via the pressure reducing tower top reflux pump, and the other path is connected to the oil washing tank area.

[0019] The asphalt pipeline at the bottom of the pressure reducing tower is connected to the asphalt tank area via the heavy oil pump at the bottom of the pressure reducing tower and the asphalt / raw material oil heat exchanger.

[0020] A method for heating coal chemical oil fractionation includes the following steps:

[0021] Step 1: The raw material heavy aromatics from the upstream tank area enters the centrifuge for solid-liquid-liquid three-phase separation. The aqueous phase flows by gravity to the phenol-ammonia water tank, and then is pumped out of the unit to the upstream coal gasification unit by the phenol-ammonia water pump. The oil phase flows by pressure to the raw material buffer tank.

[0022] Step 2: The aforementioned oil phase is pressurized by the feed pump and mixed with multi-hydrocarbon feedstock from the upstream tank area. After being heated by heat exchange in the oil / feed oil heat exchanger in the middle section of the dephenolization tower and the feed oil heater, it enters the dehydration tank. The gas phase at the top of the dehydration tank directly enters the top of the dephenolization tower. The liquid phase at the bottom of the dehydration tank is pressurized by the feed oil booster pump and then heat exchanged with the oil / feed oil heat exchanger in the middle section of the dephenolization tower, the asphalt / feed oil heat exchanger, and the oil / feed heat exchanger in the middle section of the vacuum tower before entering the lower part of the dephenolization tower.

[0023] Step 3: The vapor phase from the top of the dephenolization tower is cooled to 40°C by the top water cooler and then enters the top reflux tank for water separation and settling. The vapor phase pipeline at the top of the top reflux tank is connected to the top vacuum system to control the pressure at the top of the dephenolization tower at -0.03 MPaG. The non-condensable gas at the outlet of the vacuum pump is sent to the flare or fuel gas system. The wastewater from the top reflux tank flows by gravity to the phenol-ammonia water tank, and the oil phase, as a light hydrocarbon product, is sent to the light hydrocarbon tank area for storage by the top reflux pump.

[0024] Step 4: The reflux in the middle section of the dephenolization tower is drawn out from any tray in the middle section. After being cooled by the oil / feed oil heat exchanger in the middle section of the dephenolization tower, part of it is refluxed back to the tray above the aforementioned tray, and the other part is sent to the tank area or crude phenol extraction unit as phenol oil product after being cooled by the phenol oil water cooler.

[0025] Step 5: After the bottom oil of the dephenol removal tower is pressurized by the bottom heavy oil pump of the dephenol removal tower, part of it is heated by the bottom heater of the dephenol removal tower and returned to the dephenol removal tower, and the other part is heated by the vacuum feed heater and sent to the vacuum tower.

[0026] Step 6: The oil and gas at the top of the pressure reducing tower are cooled by the air cooler at the top of the pressure reducing tower and then enter the reflux tank at the top of the pressure reducing tower. The non-condensable gas is cooled by the water cooler at the top of the pressure reducing tower and then extracted by the top evacuation system and sent to the flare or fuel gas system. The pressure at the top of the pressure reducing tower is controlled at -0.08 MPaG.

[0027] Step 7: After the wash oil in the top reflux tank of the pressure reducing tower is pressurized by the top reflux pump, part of it is returned to the pressure reducing tower as reflux, and the other part is sent to the wash oil tank area for storage as wash oil product.

[0028] Step 8: The oil extracted from the middle section of the pressure reducing tower is pressurized by the oil pump in the middle section of the pressure reducing tower. After heat exchange in the oil / raw material heat exchanger in the middle section of the pressure reducing tower, part of it is returned to the pressure reducing tower as middle section reflux, and part of it is cooled by the anthracene oil air cooler and sent to the anthracene oil tank area for storage as anthracene oil product.

[0029] Step 9: The asphalt at the bottom of the tower is pressurized by the heavy oil pump at the bottom of the pressure reducing tower, cooled by the asphalt / raw material oil heat exchanger, and then sent to the asphalt tank area for storage.

[0030] By implementing the above technical solution, this application eliminates the need for stripping steam injection at the bottom of the dephenolization tower and vacuum distillation tower, thus avoiding dehydration in the reflux tank at the top of the vacuum distillation tower. Furthermore, by replacing the feed furnace of the dephenolization tower with a reboiler, a clear separation between phenolic oil and wash oil can be achieved, reducing the phenolic oil content in the wash oil and decreasing the amount of phenol-containing wastewater discharged. Replacing the feed heater of the dephenolization tower with a reboiler and eliminating the stripping steam injection of the dephenolization tower and vacuum distillation tower, these modifications reduce the discharge of phenol-containing wastewater and improve the quality of the wash oil product. From the perspective of energy conservation and environmental protection, this significantly saves on low-pressure steam usage, reduces wastewater discharge, and benefits future plant operation, lowering operating costs and resulting in considerable economic benefits. Attached Figure Description

[0031] The specific structure of this application is given by the following figures and embodiments:

[0032] Appendix Figure 1 This is a schematic diagram of the phenol removal tower system in this application;

[0033] Appendix Figure 2 This is a schematic diagram of the pressure reduction tower system in this application.

[0034] legend:

[0035] Phenol removal tower (C-101), vacuum tower (C-102);

[0036] Raw material buffer tank (D-101), phenol removal tower top reflux tank (D-102), vacuum tower top reflux tank (D-103), phenol ammonia water tank (D-104), dehydration tank (D-105).

[0037] Heat exchanger for oil / feed oil in the middle section of the dephenolization tower (E-101), heat exchanger for asphalt / feed oil (E-102), top water cooler of the dephenolization tower (E-103A / B), water cooler for phenolic oil (E-104A / B), feed oil heater (E-105), top water cooler of the vacuum distillation tower (E-106), heat exchanger for oil / feed oil in the middle section of the vacuum distillation tower (E-107), heat exchanger for oil / feed oil in the middle section of the dephenolization tower (E-108);

[0038] Dephenol removal tower bottom heater (F-101), vacuum feed heater (F-102);

[0039] Centrifuge (M-101A / B);

[0040] Raw material feed pump (P-101 / AB), top reflux pump of dephenolization tower (P-102A / B), middle section oil pump of dephenolization tower (P-103A / B), bottom heavy oil pump of dephenolization tower (P-104A / B), phenol-ammonia water pump (P-105A / B), raw material oil booster pump (P-106A / B), middle section oil pump of vacuum distillation tower (P-107A / B), bottom heavy oil pump of vacuum distillation tower (P-108A / B), top reflux pump of vacuum distillation tower (P-109A / B);

[0041] Top vacuum system (PK-101), top evacuation system (PK-102). Detailed Implementation

[0042] This application is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this application and the actual situation.

[0043] In this application, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0044] The present application will be further described below with reference to embodiments and accompanying drawings. Embodiments: As shown in the figure Figure 1-2As shown, a coal chemical oil fractionation heating system includes a dephenolization tower system and a vacuum tower system. The dephenolization tower system includes a dephenolization tower (C-101). A centrifuge (M-101A / B) is installed in front of the feed end of the dephenolization tower. The aqueous phase outlet of the centrifuge (M-101A / B) is connected to the phenol-ammonia water tank (D-104), and the oil phase outlet is connected to the raw material buffer tank (D-101). The discharge port of the raw material buffer tank (D-101) is connected to the feed port of the dehydration tank (D-105). A multi-hydrocarbon raw material pipeline is also connected to the pipeline connecting the two. The gas phase outlet of the dehydration tank (D-105) is connected to the top of the dephenolization tower (C-101), and the liquid phase outlet of the dehydration tank (D-105) is connected to the lower part of the dephenolization tower (C-101).

[0045] The gas phase outlet at the top of the dephenol removal tower (C-101) is connected to the top reflux tank (D-102), the gas phase outlet of the top reflux tank (D-102) is connected to the flare or fuel gas system, the liquid phase outlet of the top reflux tank (D-102) is connected to the phenol-ammonia water tank (D-104), and the oil phase outlet of the top reflux tank (D-102) is connected to the light hydrocarbon tank area.

[0046] The middle section of the phenol removal tower (C-101) is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the phenol removal tower (C-101) to form a cooling reflux pipeline, and the second outlet is connected to the tank area or crude phenol extraction unit.

[0047] The bottom of the dephenolization tower (C-101) is connected to a bottom oil pipeline, which is divided into two lines. The first line is connected to the feed inlet of the bottom heater of the dephenolization tower (F-101), and the discharge outlet of the bottom heater of the dephenolization tower (F-101) is connected to the bottom of the dephenolization tower (C-101). The second line is connected to the feed inlet of the vacuum feed heater (F-102), and the discharge outlet of the vacuum feed heater (F-102) is connected to the bottom of the vacuum tower (C-102).

[0048] The top of the pressure reducing tower (C-102) is connected to the pressure reducing tower top reflux tank (D-103). The gas phase outlet of the pressure reducing tower top reflux tank (D-103) is connected to the flare or fuel gas system. One oil phase outlet of the pressure reducing tower top reflux tank (D-103) is connected to the top of the pressure reducing tower (C-102), and the other is connected to the oil washing tank area.

[0049] The middle section of the pressure reducing tower (C-102) is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the pressure reducing tower (C-102) to form a cooling reflux pipeline, and the second outlet is connected to the anthracene oil tank area.

[0050] The bottom of the pressure relief tower (C-102) is connected to the asphalt tank area via an asphalt pipeline.

[0051] Furthermore, the phenol-ammonia water tank (D-104) is connected to the upstream coal gasification unit via the phenol-ammonia water pump (P-105A / B).

[0052] Furthermore, the feed buffer tank (D-101) is connected to the feed inlet of the dehydration tank (D-105) via the feed pump (P-101 / AB), the oil / feed oil heat exchanger in the middle section of the dephenolization tower (E-101), the feed oil heater (E-105), and the feed inlet of the dehydration tank (D-105). The feed heavy aromatics from the upstream tank area enter the centrifuge (M-101A / B) for solid-liquid-liquid three-phase separation. The aqueous phase flows by gravity to the phenol-ammonia water tank (D-104), and then is sent out of the unit to the upstream coal gasification unit via the phenol-ammonia water pump (P-105A / B). The oil phase flows by gravity under pressure to the feed buffer tank (D-101).

[0053] Furthermore, the liquid phase outlet of the dehydration tank (D-105) is connected to the lower part of the dephenolization tower (C-101) via the feed oil booster pump (P-106A / B), the oil / feed oil heat exchanger in the middle section of the dephenolization tower (E-108), the asphalt / feed oil heat exchanger (E-102), and the oil / feed heat exchanger in the middle section of the vacuum tower (E-107). The oil phase is pressurized by the feed pump (P-101 / AB) and mixed with multi-hydrocarbon feedstock from the upstream tank area. After being heated by heat exchange in the mid-section oil / feed oil heat exchanger (E-101) and feed oil heater (E-105) of the dephenolization tower, it enters the dehydration tank (D-105). The gas phase at the top of the dehydration tank directly enters the top of the dephenolization tower (C-101). The liquid phase at the bottom of the dehydration tank is pressurized by the feed oil booster pump (P-106A / B) and then heat exchanged with the mid-section oil / feed oil heat exchanger (E-108), the asphalt / feed oil heat exchanger (E-102), and the mid-section oil / feed heat exchanger (E-107) of the vacuum tower before entering the lower part of the dephenolization tower (C-101).

[0054] Furthermore, the gas phase outlet at the top of the dephenolization tower (C-101) is connected to the dephenolization tower top reflux tank (D-102) via the dephenolization tower top water cooler (E-103A / B). The gas phase outlet of the dephenolization tower top reflux tank (D-102) is connected to the flare or fuel gas system after being connected to the top vacuum system (PK-101). The oil phase outlet of the dephenolization tower top reflux tank (D-102) is connected to the light hydrocarbon tank area via the dephenolization tower top reflux pump (P-102A / B). The vapor phase from the top of the dephenolization tower is cooled to 40°C by the top water cooler (E-103A / B) and then enters the top reflux tank (D-102) for water separation and settling. The vapor phase pipeline at the top of the top reflux tank (D-102) is connected to the top vacuum system (PK-101) to control the top pressure of the dephenolization tower to -0.03 MPaG. The non-condensable gas at the outlet of the vacuum pump is sent to the flare or fuel gas system. The wastewater from the top reflux tank (D-102) flows by gravity to the phenol-ammonia water tank (D-104), and the oil phase, as a light hydrocarbon product, is sent to the tank area for storage by the top reflux pump (P-102A / B).

[0055] Furthermore, the middle section of the dephenolization tower (C-101) is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the dephenolization tower (C-101) via the oil / feedstock heat exchanger (E-108) and the oil / feedstock heat exchanger (E-101) to form a cooling reflux pipeline. The second outlet is connected to the tank area or crude phenol extraction unit via the phenol oil water cooler (E-104A / B). The reflux from the middle section of the dephenolization tower (C-101) is drawn from any tray in the middle. After being cooled by the oil / feedstock heat exchanger (E-108) and the oil / feedstock heat exchanger (E-101), part of it is refluxed back to the tray above the aforementioned tray, and the other part, as phenol oil product, is cooled by the phenol oil water cooler (E-104A / B) and then sent to the tank area or crude phenol extraction unit.

[0056] Furthermore, the bottom of the dephenolization tower (C-101) is connected to a bottom oil pipeline. This pipeline, after passing through the bottom heavy oil pump (P-104A / B), splits into two paths. The first path connects to the inlet of the bottom heater (F-101), and the outlet of the bottom heater (F-101) connects to the bottom of the dephenolization tower (C-101). The second path connects to the inlet of the vacuum feed heater (F-102), and the outlet of the vacuum feed heater (F-102) connects to the bottom of the vacuum tower (C-102). The bottom oil from the dephenolization tower (C-101) is pressurized by the bottom heavy oil pump (P-104A / B). Part of the oil is heated by the bottom heater (F-101) and returned to the dephenolization tower (C-101), while the other part is heated by the vacuum feed heater (F-102) and then sent to the vacuum tower (C-102).

[0057] Furthermore, the top of the vacuum distillation tower (C-102) is connected to the inlet of the vacuum distillation tower top reflux tank (D-103) via the vacuum distillation tower top air cooler (A-102A / B). The gas phase outlet of the vacuum distillation tower top reflux tank (D-103) is connected to the flare or fuel gas system via the vacuum distillation tower top water cooler (E-106) and the tower top evacuation system (PK-102). The oil phase outlet of the vacuum distillation tower top reflux tank (D-103) is connected to the top of the vacuum distillation tower (C-102) via the vacuum distillation tower top reflux pump (P-109A / B), and another path is connected to the wash oil tank area. After the wash oil in the vacuum distillation tower top reflux tank (D-103) is pressurized by the vacuum distillation tower top reflux pump (P-109A / B), part of it is returned to the vacuum distillation tower (C-102) as reflux, and the other part is sent to the wash oil tank area for storage as wash oil product.

[0058] The oil extracted from the middle section of the pressure reducing tower (C-102) is pressurized by the middle section oil pump (P-107A / B), and after heat exchange in the middle section oil / raw material heat exchanger (E-107), part of it is returned to the pressure reducing tower (C-102) as middle section reflux, and part of it is cooled by the anthracene oil air cooler (A-101) and sent to the anthracene oil tank area for storage as anthracene oil product.

[0059] Furthermore, the asphalt pipeline at the bottom of the vacuum distillation tower (C-102) is connected to the asphalt tank area via the vacuum distillation tower bottom heavy oil pump (P-108A / B) and the asphalt / raw material heat exchanger (E-102A / B). The asphalt at the bottom of the tower is pressurized by the vacuum distillation tower bottom heavy oil pump (P-108A / B), cooled by the asphalt / raw material heat exchanger (E-102A / B), and then sent to the asphalt tank area for storage.

[0060] A method for heating coal chemical oil fractionation includes the following steps:

[0061] Step 1: The raw material heavy aromatics from the upstream tank area enter the centrifuge (M-101A / B) for solid-liquid-liquid three-phase separation. The aqueous phase flows by gravity to the phenol-ammonia water tank (D-104), and then is sent out of the unit to the upstream coal gasification unit by the phenol-ammonia water pump (P-105A / B). The oil phase flows by gravity under pressure to the raw material buffer tank (D-101).

[0062] Step 2: The aforementioned oil phase is pressurized by the feed pump (P-101 / AB) and mixed with multi-hydrocarbon feedstock from the upstream tank area. After being heated by heat exchange in the mid-section oil / feed oil heat exchanger (E-101) and feed oil heater (E-105) of the dephenolization tower, it enters the dehydration tank (D-105). The gas phase at the top of the dehydration tank directly enters the top of the dephenolization tower (C-101). The liquid phase at the bottom of the dehydration tank is pressurized by the feed oil booster pump (P-106A / B) and then heat exchanged with the mid-section oil / feed oil heat exchanger (E-108), the asphalt / feed oil heat exchanger (E-102), and the mid-section oil / feed heat exchanger (E-107) of the vacuum tower before entering the lower part of the dephenolization tower (C-101).

[0063] Step 3: The vapor phase from the top of the dephenolization tower is cooled to 40°C by the top water cooler (E-103A / B) and then enters the top reflux tank (D-102) for water separation and settling. The vapor phase pipeline at the top of the top reflux tank (D-102) is connected to the top vacuum system (PK-101) to control the pressure at the top of the dephenolization tower to -0.03 MPaG. The non-condensable gas at the outlet of the vacuum pump is sent to the flare or fuel gas system. The wastewater from the top reflux tank (D-102) flows by gravity to the phenol-ammonia water tank (D-104), and the oil phase, as a light hydrocarbon product, is sent to the light hydrocarbon tank area for storage by the top reflux pump (P-102A / B).

[0064] Step 4: The reflux from the middle section of the dephenolization tower (C-101) is drawn from any tray in the middle section. After being cooled by the oil / feed oil heat exchanger (E-108) and the oil / feed oil heat exchanger (E-101) in the middle section of the dephenolization tower, part of it is refluxed back to the tray above the aforementioned tray, and the other part is sent to the tank area or crude phenol extraction unit after being cooled by the phenol oil water cooler (E-104A / B) as phenol oil product.

[0065] Step 5: The bottom oil of the dephenolization tower (C-101) is pressurized by the bottom heavy oil pump (P-104A / B). One part is heated by the bottom heater (F-101) and returned to the dephenolization tower (C-101), and the other part is heated by the vacuum feed heater (F-102) and sent to the vacuum tower (C-102).

[0066] Step 6: The oil and gas at the top of the pressure reducing tower (C-102) are cooled by the air cooler at the top of the pressure reducing tower (A-102A / B) and then enter the reflux tank at the top of the pressure reducing tower (D-103). The non-condensable gases are cooled by the water cooler at the top of the pressure reducing tower (E-106) and then extracted by the top evacuation system (PK-102) and sent to the flare or fuel gas system, controlling the pressure at the top of the pressure reducing tower to -0.08 MPaG.

[0067] Step 7: After the wash oil in the top reflux tank (D-103) of the pressure reducing tower is pressurized by the top reflux pump (P-109A / B), part of it is returned to the pressure reducing tower (C-102) as reflux, and the other part is sent to the wash oil tank area for storage as wash oil product.

[0068] Step 8: The oil extracted from the middle section of the pressure reducing tower (C-102) is pressurized by the middle section oil pump (P-107A / B), and after heat exchange in the middle section oil / raw material heat exchanger (E-107), part of it is returned to the pressure reducing tower (C-102) as middle section reflux, and part of it is cooled by the anthracene oil air cooler (A-101) and sent to the anthracene oil tank area for storage as anthracene oil product;

[0069] Step 9: The asphalt at the bottom of the tower is pressurized by the heavy oil pump at the bottom of the tower (P-108A / B), cooled by the asphalt / raw material oil heat exchanger (E-102A / B), and then sent to the asphalt tank area for storage.

[0070] This application eliminates the need for stripping steam injection at the bottom of the dephenolization tower and vacuum distillation tower, thus avoiding dehydration in the reflux tank at the top of the vacuum distillation tower. Furthermore, by replacing the feed furnace of the dephenolization tower with a reboiler, a clear separation between phenolic oil and wash oil can be achieved, reducing the phenolic oil content in the wash oil and decreasing the amount of phenol-containing wastewater discharged. By replacing the feed heater of the dephenolization tower with a reboiler and eliminating the stripping steam injection of the dephenolization tower and vacuum distillation tower, these modifications reduce the amount of phenol-containing wastewater discharged and improve the quality of the wash oil product.

[0071] The above-mentioned devices are all prior art, and their specific structures are not the inventive point of this application, so they will not be described in detail here.

[0072] The above description is merely an example for clearly illustrating this application and is not intended to limit the implementation of this application. Any obvious variations or modifications derived from the technical solutions of this application are still within the protection scope of this application.

Claims

1. A coal chemical oil fractionation heating system, comprising a phenol removal tower system and a vacuum distillation tower system, characterized in that: The dephenol removal tower system includes a dephenol removal tower, a centrifuge is installed in front of the feed end of the dephenol removal tower, the aqueous phase outlet of the centrifuge is connected to the phenol-ammonia water tank, the oil phase outlet is connected to the raw material buffer tank, the discharge port of the raw material buffer tank is connected to the feed port of the dehydration tank, and a multi-hydrocarbon raw material pipeline is also connected to the pipeline connecting the two. The gas phase outlet of the dehydration tank is connected to the top of the dephenol removal tower, and the liquid phase outlet of the dehydration tank is connected to the middle and lower part of the dephenol removal tower. The gas phase outlet at the top of the dephenol removal tower is connected to the top reflux tank of the dephenol removal tower. The gas phase outlet of the top reflux tank of the dephenol removal tower is connected to the flare or fuel gas system. The liquid phase outlet of the top reflux tank of the dephenol removal tower is connected to the phenol ammonia water tank. The oil phase outlet of the top reflux tank of the dephenol removal tower is connected to the light hydrocarbon tank area. The middle section of the dephenol removal tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the dephenol removal tower to form a cooling reflux pipeline, and the second outlet is connected to the tank area or crude phenol extraction unit. The bottom of the dephenol removal tower is connected to a bottom oil pipeline, which is divided into two lines. The first line is connected to the feed inlet of the bottom heater of the dephenol removal tower, and the discharge outlet of the bottom heater of the dephenol removal tower is connected to the bottom of the dephenol removal tower. The second line is connected to the feed inlet of the vacuum feed heater, and the discharge outlet of the vacuum feed heater is connected to the bottom of the vacuum tower. The top of the pressure reducing tower is connected to the pressure reducing tower top reflux tank. The gas phase outlet of the pressure reducing tower top reflux tank is connected to the flare or fuel gas system. One oil phase outlet of the pressure reducing tower top reflux tank is connected to the top of the pressure reducing tower, and the other is connected to the oil washing tank area. The middle section of the pressure reducing tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the middle section of the pressure reducing tower to form a cooling reflux pipeline, and the second outlet is connected to the anthracene oil tank area. The bottom of the pressure relief tower is connected to the asphalt tank area via an asphalt pipeline.

2. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The phenol-ammonia water tank is connected to the upstream coal gasification unit via a phenol-ammonia water pump.

3. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The raw material buffer tank is connected to the feed inlet of the dehydration tank via the raw material feed pump, the oil / raw material heat exchanger in the middle section of the dephenolization tower, and the raw material heater.

4. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The liquid phase outlet of the dehydration tank is connected to the lower part of the dephenolization tower via a feed oil booster pump, a heat exchanger for oil / feed oil in the middle section of the dephenolization tower, a heat exchanger for asphalt / feed oil, and a heat exchanger for oil / feed in the middle section of the vacuum tower.

5. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The gas phase outlet at the top of the dephenolization tower is connected to the dephenolization tower top reflux tank via the dephenolization tower top water cooler. The gas phase outlet of the dephenolization tower top reflux tank is connected to the top vacuum system of the connecting tower and then connected to the flare or fuel gas system. The oil phase outlet of the dephenolization tower top reflux tank is connected to the light hydrocarbon tank area via the dephenolization tower top reflux pump.

6. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The middle section of the dephenolization tower is connected to a reflux pipeline. The outlet of the reflux pipeline is divided into two paths. The first outlet is connected to the oil / raw material heat exchanger in the middle section of the dephenolization tower, forming a cooling reflux pipeline. The second outlet is connected to the tank area or crude phenol extraction unit via a phenol oil water cooler.

7. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The bottom of the dephenol removal tower is connected to a bottom oil pipeline. After passing through the bottom heavy oil pump of the dephenol removal tower, the bottom oil pipeline is divided into two paths. The first path is connected to the feed inlet of the bottom heater of the dephenol removal tower, and the discharge outlet of the bottom heater of the dephenol removal tower is connected to the bottom of the dephenol removal tower. The second path is connected to the feed inlet of the vacuum feed heater, and the discharge outlet of the vacuum feed heater is connected to the bottom of the vacuum tower.

8. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The top of the pressure reducing tower is connected to the feed inlet of the pressure reducing tower top reflux tank via the pressure reducing tower top air cooler. The gas phase outlet of the pressure reducing tower top reflux tank is connected to the flare or fuel gas system via the pressure reducing tower top water cooler and the tower top evacuation system. The oil phase outlet of the pressure reducing tower top reflux tank is connected to the top of the pressure reducing tower via the pressure reducing tower top reflux pump, and the other path is connected to the oil washing tank area.

9. The coal chemical oil fractionation heating system as described in claim 1, characterized in that: The asphalt pipeline at the bottom of the pressure reducing tower is connected to the asphalt tank area via the heavy oil pump at the bottom of the pressure reducing tower and the asphalt / raw material oil heat exchanger.

10. A method for heating coal chemical oil fractionation, characterized in that, Includes the following steps: Step 1: The raw material heavy aromatics from the upstream tank area enters the centrifuge for solid-liquid-liquid three-phase separation. The aqueous phase flows by gravity to the phenol-ammonia water tank, and then is pumped out of the unit to the upstream coal gasification unit by the phenol-ammonia water pump. The oil phase flows by pressure to the raw material buffer tank. Step 2: The aforementioned oil phase is pressurized by the feed pump and mixed with multi-hydrocarbon feedstock from the upstream tank area. After being heated by heat exchange in the oil / feed oil heat exchanger in the middle section of the dephenolization tower and the feed oil heater, it enters the dehydration tank. The gas phase at the top of the dehydration tank directly enters the top of the dephenolization tower. The liquid phase at the bottom of the dehydration tank is pressurized by the feed oil booster pump and then heat exchanged with the oil / feed oil heat exchanger in the middle section of the dephenolization tower, the asphalt / feed oil heat exchanger, and the oil / feed heat exchanger in the middle section of the vacuum tower before entering the lower part of the dephenolization tower. Step 3: The vapor phase from the top of the dephenolization tower is cooled to 40°C by the top water cooler and then enters the top reflux tank for water separation and settling. The vapor phase pipeline at the top of the top reflux tank is connected to the top vacuum system to control the pressure at the top of the dephenolization tower at -0.03 MPaG. The non-condensable gas at the outlet of the vacuum pump is sent to the flare or fuel gas system. The wastewater from the top reflux tank flows by gravity to the phenol-ammonia water tank, and the oil phase, as a light hydrocarbon product, is sent to the light hydrocarbon tank area for storage by the top reflux pump. Step 4: The reflux in the middle section of the dephenolization tower is drawn out from any tray in the middle section. After being cooled by the oil / feed oil heat exchanger in the middle section of the dephenolization tower, part of it is refluxed back to the tray above the aforementioned tray, and the other part is sent to the tank area or crude phenol extraction unit as phenol oil product after being cooled by the phenol oil water cooler. Step 5: After the bottom oil of the dephenol removal tower is pressurized by the bottom heavy oil pump of the dephenol removal tower, part of it is heated by the bottom heater of the dephenol removal tower and returned to the dephenol removal tower, and the other part is heated by the vacuum feed heater and sent to the vacuum tower. Step 6: The oil and gas at the top of the pressure reducing tower are cooled by the air cooler at the top of the pressure reducing tower and then enter the reflux tank at the top of the pressure reducing tower. The non-condensable gas is cooled by the water cooler at the top of the pressure reducing tower and then extracted by the top evacuation system and sent to the flare or fuel gas system. The pressure at the top of the pressure reducing tower is controlled at -0.08 MPaG. Step 7: After the wash oil in the top reflux tank of the pressure reducing tower is pressurized by the top reflux pump, part of it is returned to the pressure reducing tower as reflux, and the other part is sent to the wash oil tank area for storage as wash oil product. Step 8: The oil extracted from the middle section of the pressure reducing tower is pressurized by the oil pump in the middle section of the pressure reducing tower. After heat exchange in the oil / raw material heat exchanger in the middle section of the pressure reducing tower, part of it is returned to the pressure reducing tower as middle section reflux, and part of it is cooled by the anthracene oil air cooler and sent to the anthracene oil tank area for storage as anthracene oil product. Step 9: The asphalt at the bottom of the tower is pressurized by the heavy oil pump at the bottom of the pressure reducing tower, cooled by the asphalt / raw material oil heat exchanger, and then sent to the asphalt tank area for storage.

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