Dechlorination process and apparatus for reformer reaction products

Abstract

The application discloses a kind of reformer reaction product dechlorination process and device. Including high tank, light hydrocarbon dechlorination tank, reforming oil dechlorination tank, circulating hydrogen compressor, light hydrocarbon dechlorination tank inlet cooler, booster inlet liquid separator tank, recontacting refrigerator and recontacting tank. Reformer reaction product is entered high tank after cooling, tank top gas phase is pressurized after circulating hydrogen compressor, and is divided into two, one is as circulating hydrogen, the other is mixed with reducing hydrogen and sent into light hydrocarbon dechlorination tank to carry out dechlorination, and the light hydrocarbon after dechlorination in light hydrocarbon dechlorination tank is cooled into light hydrocarbon dechlorination tank inlet cooler, and then enters booster inlet liquid separator tank, and the liquid phase of the bottom of booster inlet liquid separator tank returns high tank, and the liquid phase of the bottom of high tank is pressurized and enters reforming oil dechlorination tank, and the gas phase of the top of booster inlet liquid separator tank is pressurized and mixed with the reforming oil after dechlorination in reforming oil dechlorination tank, and then cooled into recontacting tank to carry out gas-liquid phase separation, and the gas phase of the top is as reforming hydrogen, and the liquid phase of the bottom is as de-pentane column feed. Using the application can ensure that HCl content in reforming reaction product and treated reducing hydrogen is not more than 1ppm (v), slow down ammonium salt plugging of reforming hydrogen booster inlet and ammonium salt corrosion on the top of de-pentane column, and ensure safe and stable operation of device.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals and relates to a method for removing hydrogen chloride from hydrocarbons. Specifically, it relates to a dechlorination process and apparatus for reaction products of a reforming unit. Background Technology

[0002] Reforming is a technology that uses a bimetallic catalyst to induce molecular rearrangement and isomerization reactions at high temperatures, increasing aromatic hydrocarbon production and improving gasoline octane number. During the reaction, chlorine from the catalyst can enter downstream along with the reforming products, causing corrosion of downstream equipment. Simultaneously, hydrogen chloride from the reforming products reacts with trace amounts of ammonia to form ammonium chloride deposits, which not only clog pipes and equipment but also easily lead to corrosion beneath the ammonium chloride scale, damaging equipment.

[0003] Currently, the method for dechlorinating reforming reaction products is as follows: the reformed oil is dechlorinated before entering the depentanizer. However, due to the low mass transfer rate in the liquid-solid reaction system, the existing liquid-phase dechlorinating agent has a low chlorine capacity, requires a large amount of dechlorinating agent, and needs to be replaced frequently. This easily causes ammonium chloride blockage and corrosion in the low-temperature part at the top of the depentanizer. The fuel gas sent from the top of the tower into the fuel gas system can also cause blockage of the heater burner nozzles, requiring a separate fuel gas dechlorination tank. The hydrogen chloride in the reformed hydrogen is pressurized by the reforming hydrogen booster and purified by re-contact before being dechlorinated. The reforming hydrogen booster and related re-contact equipment are at risk of hydrogen chloride corrosion and ammonium salt blockage, affecting the safe and stable operation of the unit. There is an urgent need to find a process flow to improve the dechlorination effect and ensure the safe and stable operation of the unit.

[0004] CN102676207A discloses a method for dechlorinating catalytic reforming reaction products, comprising directly feeding the reforming reaction products flowing out of the reforming reactor into a dechlorinating agent bed, and removing chlorine from them under conditions of 480~520℃, 0.35~2.0MPa, and feed volume hourly space velocity of 200~4000 h⁻¹. This method can remove chlorine from the reforming products in one step and can effectively improve the dechlorination efficiency of the dechlorinating agent. However, its disadvantages are: all reaction products are dechlorinated (in conventional designs, circulating hydrogen is returned directly to the reaction section without dechlorination, which can reduce the amount of organic chlorine injected), and the entire dechlorination process is carried out at high temperature, resulting in high design conditions for the dechlorination tank and the use of high-temperature dechlorinating agents, leading to high investment costs. Summary of the Invention

[0005] In order to solve the above-mentioned problems, the present invention provides a dechlorination process and apparatus for the reaction products of a reforming unit, so as to solve the problem that the reforming products cause the unit to be unable to operate stably due to chlorine corrosion.

[0006] This invention provides a dechlorination process and apparatus for the reaction products of a reforming unit, the technical solution of which is as follows.

[0007] A dechlorination process for reaction products of a reforming unit, characterized by comprising the following steps:

[0008] 1) After being cooled, the reaction products of the reforming unit enter the high-efficiency separation tank. The gas phase at the top of the high-efficiency separation tank is pressurized by the circulating hydrogen compressor and divided into two streams. One stream is returned to the reaction section as circulating hydrogen, and the other stream is mixed with reducing hydrogen and sent to the light hydrocarbon dechlorination tank for dechlorination. The light hydrocarbons after dechlorination in the light hydrocarbon dechlorination tank enter the outlet cooler of the light hydrocarbon dechlorination tank for cooling, and then enter the inlet separator of the booster compressor. The liquid phase at the bottom of the booster compressor inlet separator returns to the high-efficiency separation tank. The liquid phase at the bottom of the high-efficiency separation tank is pressurized and sent to the reforming oil dechlorination tank.

[0009] 2) The gas phase at the top of the separator at the inlet of the booster is pressurized. After pressurization, it is mixed with the reformed oil after dechlorination in the reformed oil dechlorination tank and enters the re-contact refrigerator after heat exchange. The cooled mixture enters the re-contact tank for gas-liquid phase separation.

[0010] 3) The gas phase at the top of the re-contact tank is fed into other units as reformed hydrogen, and the liquid phase at the bottom of the tank is fed into the depentanizer as feed to the depentanizer.

[0011] The present invention discloses a dechlorination process for the reaction products of a reforming unit, further characterized in that: in step 1), the reaction products of the reforming unit are cooled by the reaction product air cooler and then enter the high-efficiency separation tank; the liquid phase at the bottom of the high-efficiency separation tank is pressurized by the high-efficiency separation tank bottom pump and then sent to the reformed oil dechlorination tank; in step 2), the gas phase at the top of the separator of the booster pump enters the reformed hydrogen booster pump for pressurization.

[0012] The present invention discloses a dechlorination process for reaction products of a reforming unit, the further technical feature of which is that the reforming unit includes a semi-regenerative reforming unit and a continuous reforming unit.

[0013] The present invention discloses a dechlorination process for reaction products of a reforming unit, the further technical feature of which is that the operating pressure of the high-precision separator is 0.15~0.25 MPa (gauge pressure) and the operating temperature is 40~50℃.

[0014] The present invention discloses a dechlorination process for reaction products of a reforming unit, the further technical feature of which is that the operating pressure of the inlet separator of the booster is 0.50~0.80 MPa and the operating temperature is 40~50℃.

[0015] The present invention discloses a dechlorination process for reaction products of a reforming unit, the further technical feature of which is that the operating pressure of the re-contact tank is 1.5~3.0 MPa (gauge pressure) and the operating temperature is -10~40℃.

[0016] The present invention discloses a dechlorination process for reaction products of a reforming unit, further characterized in that: the operating pressure of the light hydrocarbon dechlorination tank is 0.50~0.80 MPa (gauge pressure) and the operating temperature is 90~120℃; the operating pressure of the reformed oil dechlorination tank is 1.20~3.50 MPa (gauge pressure).

[0017] The present invention discloses a dechlorination process for reaction products of a reforming unit, wherein the re-contact cooler contains, but is not limited to, propane, propylene, liquid ammonia, and chilled water.

[0018] This invention also provides a dechlorination device for the reaction products of a reforming unit, used in the aforementioned dechlorination process of the reaction products of the reforming unit. The dechlorination device includes a high-precision separator, a circulating hydrogen compressor, a light hydrocarbon dechlorination tank, a reformate dechlorination tank, a booster compressor inlet separator, a light hydrocarbon dechlorination tank outlet cooler, a re-contact cooler, and a re-contact tank. The high-precision separator has a reaction product inlet in its middle section, and a reaction product feed pipeline is connected to this inlet. The bottom of the high-precision separator is connected to the inlet of the reformate dechlorination tank, and the top outlet of the high-precision separator is connected to the inlet of the circulating hydrogen compressor. The circulating hydrogen compressor has two outlets, one of which is... Connected to the circulating hydrogen return pipeline, the outlet pipeline of the other outlet and the reduced hydrogen pipeline are connected to the inlet of the light hydrocarbon dechlorination tank. The outlet of the light hydrocarbon dechlorination tank is connected to the inlet of the light hydrocarbon dechlorination tank outlet cooler. The outlet of the light hydrocarbon dechlorination tank outlet cooler is connected to the inlet of the booster compressor inlet separator. The bottom outlet of the booster compressor inlet separator is connected to the inlet of the reforming unit reaction product of the high-precision separator via a pipeline. The outlet of the reforming oil dechlorination tank and the top outlet of the booster compressor inlet separator are connected to the inlet of the re-contact cooler. The outlet of the re-contact cooler is connected to the inlet of the re-contact tank. The top outlet of the re-contact tank is connected to the reforming hydrogen pipeline. The bottom outlet of the re-contact tank is connected to the depentanizer feed pipeline.

[0019] The present invention discloses a dechlorination device for reaction products of a reforming unit, further characterized in that: the dechlorination device for reaction products of the reforming unit also includes a reaction product air cooler, a reforming hydrogen booster compressor, and a high-separation tank bottom pump. The reaction product air cooler is provided on the reaction product feed pipeline of the reforming unit. The top outlet of the booster compressor inlet and the top outlet of the separator are connected to the inlet of the re-contact cooler through the reforming hydrogen booster compressor. The bottom of the high-separation tank is connected to the inlet of the reformed oil dechlorination tank through the high-separation tank bottom pump.

[0020] The present invention provides a dechlorination device for the reaction products of a reforming unit, the further technical feature of which is that a defoaming screen is provided in the high-precision tank, which can effectively prevent liquid from being carried over to the reforming hydrogen booster.

[0021] The present invention discloses a dechlorination device for the reaction products of a reforming unit, the further technical feature of which is that: the inlet separator of the booster is equipped with a defoaming screen, under this operating condition, 85% to 95% of the fuel gas passes through the light hydrocarbon dechlorination tank with high chlorine capacity and good dechlorination effect, thereby improving the dechlorination effect of the fuel gas and reducing the corrosion of ammonium salt at the top of the subsequent depentane deionization tower and the blockage of the heater burner nozzle.

[0022] The present invention discloses a dechlorination device for reaction products of a reforming unit, the further technical feature of which is that: two light hydrocarbon dechlorination tanks are provided, which can be connected in series or in parallel, and a gas-phase dechlorination agent is used, which has a good dechlorination effect and can avoid the blockage of ammonium salt at the inlet of the reforming hydrogen booster, thus ensuring the stable operation of the reforming hydrogen booster.

[0023] The present invention discloses a dechlorination device for the reaction products of a reforming unit, wherein the further technical feature is that: two dechlorination tanks for reforming oil are provided, which can be connected in series or in parallel, and can be switched according to the chlorine saturation of the dechlorinating agent without affecting the normal operation of the unit.

[0024] The present invention provides a dechlorination device for the reaction products of a reforming unit, wherein the further technical feature is that a defoaming screen is provided inside the re-contact tank.

[0025] The reformed hydrogen can be fed into other devices, either into a PSA unit for further purification or into a hydrogen refining unit as a hydrogen source.

[0026] The present invention provides a method and apparatus for dechlorination of reaction products in a reforming unit, which has the following advantages compared with the prior art:

[0027] 1) In this invention, the light hydrocarbon dechlorination tank adopts gas phase dechlorination, which has a good dechlorination effect and can effectively remove chlorine from reforming hydrogen and light hydrocarbons. It avoids ammonium salt deposition caused by long-term operation and blockage of the inlet filter of the reforming hydrogen booster, thus ensuring long-term operation of the unit.

[0028] 2) In this invention, about 85% to 95% of the fuel gas components in the reforming product are dechlorinated by the light hydrocarbon dechlorination tank, which improves the dechlorination effect of the fuel gas and can reduce the blockage of ammonium salt deposition at the top of the depentane tower and the blockage of the heater burner.

[0029] 3) The reforming oil dechlorination tank of the present invention is located at the outlet of the bottom pump of the high-precision tank. The liquid phase at the bottom of the tank contains fewer light components, which can reduce the amount of dechlorinating agent loaded in the reforming oil dechlorination tank and the amount of waste dechlorinating agent discharged.

[0030] 4) The present invention provides two light hydrocarbon dechlorination tanks and two reformate dechlorination tanks, which can be connected in series or in parallel, and the switching does not affect the normal operation of the equipment.

[0031] 5) The light hydrocarbon dechlorination tank of this invention is located at the outlet of the circulating hydrogen, which can make full use of the heat generated by gas pressurization. The dechlorination agent is a conventional gas phase dechlorination agent. After dechlorination, the light hydrocarbons are cooled by the outlet cooler of the light hydrocarbon dechlorination tank and then enter the inlet separator of the booster for separation, which can avoid liquid accumulation in the reforming hydrogen booster.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this does not limit the scope of the invention. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the dechlorination process of the reaction products of a reforming unit according to the present invention.

[0034] The reference numerals in the figure are:

[0035] 1-Reformation reaction product, 2-Reaction product air cooler, 3-High-efficiency separation tank, 4-Circulating hydrogen compressor, 5-Circulating hydrogen, 6-Light hydrocarbon dechlorination tank, 7-Reformation hydrogen booster compressor, 8-High-efficiency separation tank bottom pump, 9-Reformation oil dechlorination tank, 10-Re-contact cooler, 11-Re-contact tank, 12-Reformation hydrogen, 13-Depentane tower feed, 14-Reduced hydrogen, 15-Booster inlet separator, 16-Light hydrocarbon dechlorination tank outlet cooler. Detailed Implementation

[0036] The present invention will now be further described with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the dechlorination unit for the reforming reaction products includes a reaction product air cooler 2, a high-efficiency separation tank 3, a light hydrocarbon dechlorination tank outlet cooler 16, a booster compressor inlet separator 15, a light hydrocarbon dechlorination tank 6, a circulating hydrogen compressor 4, a high-efficiency separation tank bottom pump 8, a reforming oil dechlorination tank 9, a reforming hydrogen booster compressor 7, a re-contact cooler 10, and a re-contact tank 11. The high-efficiency separation tank 3 has a reforming reaction product inlet in the middle, and the reforming reaction product feed pipeline is connected to the reforming reaction product inlet. The reforming reaction product feed pipeline is equipped with a reaction product air cooler 2. The bottom outlet of the high-efficiency separation tank 3 is connected to the inlet of the reforming oil dechlorination tank 9 via the high-efficiency separation tank bottom pump 8. The top outlet of the high-efficiency separation tank 3 is connected to the inlet of the circulating hydrogen compressor 4. The circulating hydrogen compressor 4 has two outlets: one outlet is connected to the circulating hydrogen return pipeline, and the other outlet's outlet pipeline is connected to the reduced hydrogen pipeline (either separately or jointly). Figure 1(After merging) is connected to the inlet of light hydrocarbon dechlorination tank 6; the outlet of light hydrocarbon dechlorination tank 6 is connected to the inlet of light hydrocarbon dechlorination tank outlet cooler 16; the outlet of light hydrocarbon dechlorination tank outlet cooler 16 is connected to the inlet of booster compressor inlet separator 15; the bottom outlet of booster compressor inlet separator 15 is connected via pipeline to the inlet of the reforming unit reaction product of high-strength separator 3; the top outlet of booster compressor inlet separator 15 is connected to the inlet of reforming hydrogen booster compressor 7; the outlet of reforming oil dechlorination tank 9 and the outlet of reforming hydrogen booster compressor 7 (separately or after merging) Figure 1 (After merging) is connected to the inlet of the re-contact cooler 10, the outlet of the re-contact cooler 10 is connected to the inlet of the re-contact tank 11, the top outlet of the re-contact tank 11 is connected to the reforming hydrogen pipeline, and the bottom outlet of the re-contact tank is connected to the depentanizer feed pipeline.

[0038] The following is a simplified description of the dechlorination process of the reaction products of the reforming unit of the present invention, with reference to the accompanying drawings.

[0039] After being cooled by the product air cooler 2, the reforming product 1 enters the high-efficiency separation tank 3. The gas phase at the top of the high-efficiency separation tank 3 is pressurized by the circulating hydrogen compressor 4 and divided into two streams. One stream is returned to the reaction section as circulating hydrogen 5, and the other stream is mixed with the reducing hydrogen 14 and enters the light hydrocarbon dechlorination tank 6. The dechlorinated light hydrocarbons are cooled by the outlet cooler 16 of the light hydrocarbon dechlorination tank and sent to the inlet separator 15 of the booster compressor. The gas phase at the top of the inlet separator 15 of the booster compressor enters the reforming hydrogen booster compressor 7 for pressurization, and the liquid phase at the bottom of the inlet separator 15 of the booster compressor returns to the high-efficiency separation tank 3.

[0040] The liquid phase at the bottom of the high-pressure separation tank 3 is pressurized by the high-pressure separation tank bottom pump 8 and sent to the reforming oil dechlorination tank 9 for dechlorination. After dechlorination, the reforming oil and the light hydrocarbons pressurized by the reforming hydrogen booster 7 are mixed and enter the re-contact refrigeration unit 10. The cooled mixture flows into the re-contact tank 11 for gas-liquid phase separation. The gas phase at the top of the tank is sent out as reforming hydrogen 12, and the liquid phase at the bottom of the tank is fed into the depentanizer tower 13.

[0041] The high-resolution tank 3 is equipped with a defoaming screen, which can effectively prevent liquid from being carried over to the circulating hydrogen compressor.

[0042] The inlet separator 15 of the booster is equipped with a defoaming screen, which can effectively prevent liquid from being carried into the reforming hydrogen booster 7.

[0043] Two units are provided for both the light hydrocarbon dechlorination tank 6 and the reformate dechlorination tank 9. They can be connected in series or in parallel, and switching will not affect the normal operation of the unit. Conventional gaseous and liquid phase dechlorination agents can be used.

[0044] The above description is merely a typical embodiment of the present invention and does not impose any limitation on the present invention. Any changes or modifications made by those skilled in the art based on the above content without departing from the scope of the present invention should be considered equivalent examples of equivalent variations. Any equivalent changes made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are all within the scope of the present invention.

Claims

1. A dechlorination process for reaction products of a reforming unit, characterized in that... Includes the following steps: 1) After being cooled, the reaction products of the reforming unit enter the high-efficiency separation tank. The gas phase at the top of the high-efficiency separation tank is pressurized by the circulating hydrogen compressor and divided into two streams. One stream is returned to the reaction section as circulating hydrogen, and the other stream is mixed with reducing hydrogen and sent to the light hydrocarbon dechlorination tank for dechlorination. The light hydrocarbons after dechlorination in the light hydrocarbon dechlorination tank enter the outlet cooler of the light hydrocarbon dechlorination tank for cooling, and then enter the inlet separator of the booster compressor. The liquid phase at the bottom of the booster compressor inlet separator returns to the high-efficiency separation tank. The liquid phase at the bottom of the high-efficiency separation tank is pressurized and sent to the reforming oil dechlorination tank. 2) The gas phase at the top of the separator at the inlet of the booster is pressurized. After pressurization, it is mixed with the reformed oil after dechlorination in the reformed oil dechlorination tank and enters the re-contact refrigerator after heat exchange. The cooled mixture enters the re-contact tank for gas-liquid phase separation. 3) The gas phase at the top of the re-contact tank is fed into other units as reformed hydrogen, and the liquid phase at the bottom of the tank is fed into the depentanizer as feed to the depentanizer. In step 2), the vapor phase at the top of the inlet separator of the booster enters the reforming hydrogen booster for pressurization; The high-pressure separator operates at a gauge pressure of 0.15~0.25MPa and an operating temperature of 40~50℃. The operating pressure of the light hydrocarbon dechlorination tank is 0.50~0.80 MPa (gauge pressure), and the operating temperature is 90~120℃; the operating pressure of the reformate dechlorination tank is 1.20~3.50 MPa (gauge pressure).

2. The dechlorination process for the reaction products of a reforming unit according to claim 1, characterized in that: In step 1), the reaction products of the reforming unit are cooled by the reaction product air cooler and then enter the high-efficiency separation tank. The liquid phase at the bottom of the high-efficiency separation tank is pressurized by the high-efficiency separation tank bottom pump and then sent to the reformate dechlorination tank.

3. The dechlorination process for the reaction products of a reforming unit according to claim 1, characterized in that: The operating pressure of the inlet separator of the booster is 0.50~0.80 MPa (gauge pressure), and the operating temperature is 40~50℃.

4. The dechlorination process for reaction products of a reforming unit according to claim 1, characterized in that: The operating pressure of the re-contact tank is 1.5~3.0 MPa (gauge pressure), and the operating temperature is -10~40℃.

5. A dechlorination device for the reaction products of a reforming unit, used in the dechlorination process of the reaction products of the reforming unit as described in claim 1, characterized in that: The dechlorination unit for the reforming reaction products includes a high-precision separator, a circulating hydrogen compressor, a light hydrocarbon dechlorination tank, a reforming oil dechlorination tank, a booster compressor inlet separator, a light hydrocarbon dechlorination tank outlet cooler, a re-contact cooler, and a re-contact tank. The high-precision separator has a reforming reaction product inlet in its middle section, connected to the reforming reaction product feed line. The bottom of the high-precision separator is connected to the reforming oil dechlorination tank inlet, and the top outlet of the high-precision separator is connected to the circulating hydrogen compressor inlet. The circulating hydrogen compressor has two outlets: one connected to the circulating hydrogen return line, and the other outlet pipe... The light hydrocarbon dechlorination tank line and the reduced hydrogen pipeline are connected to the inlet of the light hydrocarbon dechlorination tank. The outlet of the light hydrocarbon dechlorination tank is connected to the inlet of the light hydrocarbon dechlorination tank outlet cooler. The outlet of the light hydrocarbon dechlorination tank outlet cooler is connected to the inlet of the booster compressor inlet separator. The bottom outlet of the booster compressor inlet separator is connected to the inlet of the reforming unit reaction product in the high-pressure separator via a pipeline. The outlet of the reforming oil dechlorination tank and the top outlet of the booster compressor inlet separator are connected to the inlet of the re-contact cooler. The outlet of the re-contact cooler is connected to the inlet of the re-contact tank. The top outlet of the re-contact tank is connected to the reforming hydrogen pipeline. The bottom outlet of the re-contact tank is connected to the depentanizer feed pipeline.

6. A dechlorination device for the reaction products of a reforming unit according to claim 5, characterized in that: The dechlorination unit for the reaction products of the reforming unit also includes a reaction product air cooler, a reforming hydrogen booster, and a bottom pump for the high-separation tank. The reaction product air cooler is installed on the feed pipeline of the reforming unit reaction products. The top outlet of the booster inlet and the top outlet of the separator are connected to the inlet of the re-contact cooler through the reforming hydrogen booster. The bottom of the high-separation tank is connected to the inlet of the reformed oil dechlorination tank through the bottom pump for the high-separation tank.

7. A dechlorination device for the reaction products of a reforming unit according to claim 5, characterized in that: Defoaming screens are installed inside the high-precision separator, the inlet separator of the booster, and the re-contact tank.

8. A dechlorination device for the reaction products of a reforming unit according to claim 5, characterized in that: Two units are provided for both the light hydrocarbon dechlorination tank and the reformate dechlorination tank, which can be connected in series or in parallel.

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