Method for regenerating a dryer and an alkane aromatization system

Abstract

The present application relates to the field of alkane aromatization, and discloses a method for regenerating a dryer and an alkane aromatization system, which comprises: using a material containing C6-C7 alkane as a liquid regenerant to perform first regeneration on a liquid feed drying regeneration unit of an alkane aromatization reaction; and using a hydrogen-rich gas as a gas regenerant to perform second regeneration on a gas feed drying regeneration unit of the alkane aromatization reaction. The regeneration method provided by the present application is simple to operate, avoids fluctuations in device operation caused by replacement of different materials, and saves energy and reduces consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alkane aromatization technology, and particularly relates to a method for regenerating a dryer and an alkane aromatization system. BACKGROUND

[0002] BTX (benzene, toluene, xylene) is a basic and important organic raw material in petroleum chemical industry, which is mainly derived from catalytic reforming of naphtha and pyrolysis gasoline. With the large-scale development and utilization of shale gas, ethane replaces naphtha as a cracking raw material to produce ethylene, which makes the yield of aromatic hydrocarbons from pyrolysis gasoline decrease, and with the continuous increase of the production capacity of downstream products of aromatic hydrocarbons, the gap of aromatic hydrocarbons becomes more and more obvious, so the production technology of high-yield aromatic hydrocarbons has clear market demand.

[0003] The alkane aromatization technology based on Pt / KL molecular sieve catalyst is a process technology for converting low-octane low-aromatic-potential light naphtha raw material rich in C6-C7 paraffins into light aromatic hydrocarbons with high selectivity, which is used for producing aromatic hydrocarbons. In the C6-C7 alkane aromatization technology, usually, the C6 alkane and / or C7 alkane aromatization reaction is carried out in a fixed bed reactor, the feed rich in C6 and / or C7 paraffins is mixed with hydrogen-rich gas, and is contacted with Pt / KL series catalyst in a separate aromatization reaction unit to be dehydrocyclization-converted into benzene, toluene and other light aromatic hydrocarbons. In the C6-C7 alkane aromatization reaction, water is a poison that reduces the aromatization reaction activity, aromatic hydrocarbon selectivity and service life of the Pt / KL series catalyst. In order to enable the Pt / KL catalyst to maintain its aromatization activity and selectivity during continuous long-time operation, the water content of the alkane aromatization reaction feed is less than 1 ppm. Therefore, for the C6-C7 alkane aromatization reaction, whether it is a gas feed rich in hydrogen gas or a liquid feed rich in C6 and / or C7 light paraffins, it must be subjected to a separate dehydration unit for dehydration operation before entering the aromatization reactor, so as to improve the reaction performance of the catalyst.

[0004] In addition, water may be generated at each link during the use of the catalyst. For example, water is generated during the hydrogen reduction of the catalyst due to the process of reducing metal oxides on the catalyst to metal; the water content of the reaction feed is much greater than 1 ppm even after conventional evaporation dehydration; and water is also generated in the process of abnormal process such as water leakage to the reaction feed or the reaction feed being contaminated by oxygen-containing compounds. Currently, 3A molecular sieve desiccant, 4A molecular sieve desiccant, 5A molecular sieve desiccant, 13X molecular sieve desiccant and the like are usually used for drying the feed.

[0005] Generally, nitrogen is used as the regenerant for the regeneration of the molecular sieve dryer. CN102226097A provides a method for regenerating the dryer of a catalytic pyrolysis device using circulating nitrogen as the regenerant. In the C6-C7 alkane aromatization reaction, the C6 and / or C7 alkane-rich stream is the liquid feed, and the hydrogen-rich gas is the gas feed. As described above, whether it is the C6 and / or C7 alkane-rich liquid feed or the hydrogen-rich gas, both must be dehydrated by a separate molecular sieve dryer before entering the aromatization reactor. In addition, due to the strict requirement of the water content of the feed for the Pt / KL molecular sieve catalyst used in the C6-C7 alkane aromatization reaction, the frequency of the regeneration of the dryer is high. If nitrogen is used as the regenerant for the regeneration of the dryer, for the liquid feed dryer, all the liquid feed in the dryer must be removed before the regeneration, and then nitrogen is introduced to replace the liquid feed before the regeneration; for the gas feed dryer, the original gas in the dryer must also be completely replaced before the regeneration. In this way, the use of nitrogen as the regenerant for the regeneration of the dryer is complicated and has a long cycle. SUMMARY

[0006] The present application aims to overcome the above-mentioned problems in the prior art and provide a method for regenerating a dryer and an alkane aromatization system. The method for regenerating a dryer provided by the present application is simple to operate and avoids fluctuations in the operation of the device caused by the replacement of different materials, thereby saving energy and reducing consumption.

[0007] To achieve the above-mentioned purpose, the present application provides a method for regenerating a dryer, which comprises:

[0008] The liquid regeneration unit for the liquid feed of the alkane aromatization reaction is regenerated for the first time using a material containing C6-C7 alkane as the liquid regenerant, and the gas regeneration unit for the gas feed of the alkane aromatization reaction is regenerated for the second time using hydrogen-rich gas as the gas regenerant.

[0009] The present application provides an alkane aromatization system, which comprises an aromatization reaction unit, a product fractionation unit, and an aromatic extraction unit connected in series, and a liquid feed regeneration unit and a gas feed regeneration unit connected to the inlet of the aromatization reaction unit, respectively.

[0010] The liquid feed regeneration unit is provided with a liquid regenerant supply pipeline for providing a material containing C6-C7 alkane to the liquid feed regeneration unit to regenerate the liquid feed regeneration unit for the first time.

[0011] The gas feed regeneration unit is provided with a gas regenerant supply pipeline for providing hydrogen-rich gas to the gas feed regeneration unit to regenerate the gas feed regeneration unit for the second time.

[0012] The present application provides a system and method for in-situ cyclic regeneration, in particular, a method for in-situ cyclic regeneration of liquid feed drying regeneration units with liquid regenerants and gas feed drying regeneration units with gas regenerants.

[0013] The method provided by the present application uses C6-C7 alkane-containing materials as liquid regenerants for the liquid feed drying regeneration units and uses hydrogen-rich gas as gas regenerants for the gas feed drying regeneration units, and the regeneration method is simple to operate, the regenerants used are similar in composition to the feed, and fluctuations in device operation caused by replacement of different materials are avoided. In a preferred case, at least one dryer in the liquid feed drying regeneration unit is regenerated, and at least one dryer is used for drying the liquid feed for the alkane aromatization reaction; at least one dryer in the gas feed drying regeneration unit is regenerated, and at least one dryer is used for drying the gas feed for the alkane aromatization reaction. In this preferred embodiment, continuous operation of drying and regeneration at the same time can be achieved, so that the dried feed continuously and uninterruptedly enters the reaction system, and the liquid regenerant discharged during and after regeneration is sent to the raw material tank area for cyclic reaction. The method provided by the present application is not only simple to operate, but also can realize continuous operation of drying and regeneration at the same time, thereby saving energy and reducing consumption. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic diagram of an alkane aromatization device according to an embodiment of the present application;

[0015] Figure 2 is a schematic diagram of a liquid feed drying regeneration unit according to an embodiment of the present application;

[0016] Figure 3 is a schematic diagram of a gas feed drying regeneration unit according to an embodiment of the present application.

[0017] BRIEF DESCRIPTION OF DRAWINGS

[0018] DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values should be interpreted as approximately between the stated values and include values near the stated values. For values which are ranges, e.g., "between 1 and 5", "between 1 and 5" is specifically disclosed as an embodiment. For values which are ranges, e.g., "between 1 and 5", "between 1 and 5" is specifically disclosed as an embodiment.

[0020] In the present application, unless otherwise specified, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, "inner" and "outer" refer to the inner and outer contours of the respective components.

[0021] In the present application, the singular forms "a", "an" and "the" include plural forms, and the reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. When a value is expressed as an approximation using the antecedent "about", it is to be understood that the particular value forms another embodiment. As used herein, "about X" (where X is a numerical value) preferably means ±10% of the value referred to, including the end values. For example, the phrase "about 8" preferably means a value of 7.2 to 8.8, including the end values. In the present application, all ranges are inclusive and combinable. For example, when a range of "1 to 5" is recited, the recited range should be interpreted to include ranges of "1 to 4", "1 to 3", "1-2 and 4-5", "1-3 and 5", "2-5", etc. In addition, when a list of alternatives is explicitly provided, such a list can be interpreted to mean that any alternative can be excluded, for example, by negative limitation in a claim. For example, when a range of "1 to 5" is recited, the recited range can be interpreted to include cases where any of 1, 2, 3, 4, or 5 is negatively excluded; thus, a recitation of "1 to 5" can be interpreted as "1 and 3-5, but not 2", or simply "where 2 is not included".

[0022] Unless otherwise explicitly stated, the term "substantially" as used herein, such as "substantially the same", will be understood to encompass parameters having fluctuations within a suitable range, for example, with a ±10% or ±15% fluctuation in the parameter. In some embodiments, the range of fluctuation is within ±10%, preferably within ±1%.

[0023] In the present application, unless otherwise specified, the terms "first", "second" do not serve to specifically limit, but only to distinguish different devices or operations performed in different steps.

[0024] The first aspect of the present application provides a method for regenerating a dryer, the method comprising:

[0025] The first regeneration of the liquid feed drying regeneration unit of the alkane aromatization reaction is carried out by using a material containing C6-C7 alkane as a liquid regenerant, and the second regeneration of the gas feed drying regeneration unit of the alkane aromatization reaction is carried out by using a hydrogen-rich gas as a gas regenerant.

[0026] According to the present application, preferably, the first regeneration conditions include that the regeneration temperature is 200-350℃, the regeneration pressure is 0.2-1MPa, the regeneration time is 2-20 hours, and the feed mass space velocity of the liquid regenerant is 0.1-3h -1 -1; further preferably, the first regeneration conditions include that the regeneration temperature is 250-320℃, the regeneration pressure is 0.4-0.6MPa, the regeneration time is 4-10 hours, and the feed mass space velocity of the liquid regenerant is 0.5-2h -1 .

[0027] According to the present application, preferably, the first regeneration conditions make the components in the liquid regenerant not substantially react.

[0028] According to the present application, preferably, the second regeneration conditions include that the regeneration temperature is 150-350℃, the regeneration pressure is 0.3-2MPa, the regeneration time is 2-20 hours, and the feed volume space velocity of the gas regenerant is 25-900h -1 ; preferably, the second regeneration conditions include that the regeneration temperature is 200-300℃, the regeneration pressure is 0.4-1MPa, the regeneration time is 4-10 hours, and the feed volume space velocity of the gas regenerant is 100-600h -1 . The preferred embodiment is more conducive to the faster dehydration regeneration of the drying agent. According to the present application, any composition of the material containing C6-C7 alkane in the prior art can be used as a liquid regenerant for the first regeneration of the liquid feed drying regeneration unit of the alkane aromatization reaction. In order to achieve the purpose of in-situ cyclic regeneration, preferably, the liquid regenerant is a liquid stream containing C6 and / or C7 paraffin, preferably at least one selected from light naphtha containing C6 and / or C7 paraffin, reforming raffinate and Fischer-Tropsch generated oil; further preferably, the C6 and / or C7 paraffin is at least one selected from n-hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, 2-methylpentane and 3-methylpentane.

[0029] The present application has a wide range of selection for the liquid regenerant, preferably, the content of C6 and / or C7 paraffin is greater than 90% by weight based on the total amount of the liquid regenerant; more preferably, the content of n-alkane is 20-70% by weight and the content of iso-alkane is 25-75% by weight based on the total amount of the liquid regenerant.

[0030] According to a most preferred embodiment of the present application, the liquid regenerant of the liquid feed drying and regenerating unit is a liquid stream rich in C6 and / or C7 paraffins of one or more components in the liquid feed of the alkane aromatization reaction. Preferably, the liquid regenerant is similar to and / or the same as the liquid feed fraction of the alkane aromatization reaction. The use of this preferred embodiment introduces a regenerant that is more similar to the feed composition, which is more conducive to avoiding fluctuations in the operation of the device caused by the replacement of different materials, and can achieve continuous operation of drying and regeneration at the same time, saving energy and reducing consumption.

[0031] According to a preferred embodiment of the present application, at least part of the liquid regenerant is provided by the liquid material dried by the liquid feed drying and regenerating unit. The proportion of the liquid regenerant in the liquid material dried by the liquid feed drying and regenerating unit is selected in a wide range, in order to meet the goals of regeneration and continuous production, preferably the mass flow rate of the liquid regenerant is 5% to 30% of the mass flow rate of the liquid material, and further preferably 10% to 20%.

[0032] According to the present application, preferably, the volume content of hydrogen in the gas regenerant is not less than 80%, preferably not less than 85%, and more preferably not less than 90%.

[0033] The present application has a wide range of sources for the hydrogen-rich gas, which can be derived from outside the system, or from within the system. It can be a hydrogen-rich gas after drying, or a hydrogen-rich gas obtained by fractionation after the alkane aromatization reaction. Preferably, at least part of the gas regenerant is provided by the hydrogen-rich gas obtained by fractionation after the alkane aromatization reaction.

[0034] According to the present application, preferably, the liquid feed drying and regenerating unit comprises at least two dryers connected in series and / or in parallel; the gas feed drying and regenerating unit comprises at least two dryers connected in series and / or in parallel. In the present application, the dryers are connected in parallel, which can increase the processing capacity of the dryers, and the dryers are connected in series, which can enable the different dryers to be regenerated alternately. Those skilled in the art can appropriately select the number and connection relationship of the dryers according to actual needs.

[0035] According to the present application, preferably, at least one of the dryers in the liquid feed drying and regeneration unit is regenerated, and the other dryers are used for drying the liquid feed for the aromatization reaction of alkanes; and / or, at least one of the dryers in the gas feed drying and regeneration unit is regenerated, and the other dryers are used for drying the gas feed for the aromatization reaction of alkanes. In this preferred embodiment, one dryer is operated under regeneration conditions for regeneration, while the other dryers are operated under drying conditions for drying, so that the dried feed continuously and uninterruptedly enters the reaction system. The regenerated dryer can be put into use after the regeneration agent is removed from the dryer, and the regeneration agent discharged during regeneration and before use can be sent to the reaction raw material tank for recycling.

[0036] According to the method provided by the present application, preferably, when the water content in the outlet material of the dryer in the liquid feed drying and regeneration unit is above 1 ppm, the dryer is cut out of the system for the first regeneration; preferably, the method further comprises cutting the dryer after the first regeneration into the system and connecting it after the last dryer for drying the liquid feed for the aromatization reaction of alkanes.

[0037] According to the method provided by the present application, preferably, when the water content in the outlet material of the dryer in the gas feed drying and regeneration unit is above 5 ppm, the dryer is cut out of the system for the second regeneration; preferably, the method further comprises cutting the dryer after the second regeneration into the system and connecting it after the last dryer for drying the gas feed for the aromatization reaction of alkanes.

[0038] In the method provided by the present application, the regenerated dryer can be cut into the system again for drying the reaction material, and can be used as a post-dryer together with other dryers for feed drying operation. When the pre-dryer is disabled, it is cut out of the drying system and operated under regeneration conditions for regeneration. The dryer that has been regenerated and put into use continues to operate under drying conditions for feed drying. After the regenerated dryer is regenerated, it is put into the drying system again and used as a post-dryer together with other dryers for feed drying operation. In this way, the dryers are cycled for regeneration-drying-regeneration-drying operation, and continuously obtain dried feed.

[0039] According to a most preferred embodiment of the present application, the liquid feed drying and regeneration unit comprises N stages of drying and regeneration devices connected in series, and each stage of drying and regeneration device is provided with at least one dryer, wherein N≥2; the method comprises the following steps:

[0040] (1) under the liquid feed drying conditions, the liquid feed is dried in the N stages of drying and regeneration devices connected in series, and the outlet material of the former stage is used as the inlet material of the latter stage;

[0041] (2) when the water content in the partial-stage drying regeneration device is above 1 ppm, the first regeneration is performed on the partial-stage drying regeneration device cut out, and at the same time, the liquid feed is switched to be fed to the preceding stage of the remaining partial-stage drying regeneration device for drying;

[0042] (3) after the first regeneration of the partial-stage drying regeneration device, the regenerated drying regeneration device is cut in; preferably, the regenerated drying regeneration device is connected in series after the final-stage drying regeneration device.

[0043] According to a most preferred embodiment of the present application, the gas feed drying regeneration unit comprises N stages of drying regeneration devices connected in series, each stage of drying regeneration device is provided with at least one dryer, wherein N≥2; the method comprises the following steps:

[0044] (1) under the condition of gas feed drying, the gas feed is dried in the N stages of drying regeneration devices connected in series, and the discharge of the preceding stage is used as the feed of the following stage;

[0045] (2) when the water content in the partial-stage drying regeneration device is above 5 ppm, the first regeneration is performed on the partial-stage drying regeneration device cut out, and at the same time, the gas feed is switched to be fed to the preceding stage of the remaining partial-stage drying regeneration device for drying;

[0046] (3) after the first regeneration of the partial-stage drying regeneration device, the regenerated drying regeneration device is cut in; preferably, the regenerated drying regeneration device is connected in series after the final-stage drying regeneration device.

[0047] According to the present application, preferably, the condition of liquid feed drying comprises that the temperature is 30-70℃, the pressure is 0.2-1 MPa, preferably 0.4-0.6 MPa, the mass space velocity is 2-10 h -1 .

[0048] According to the present application, preferably, the condition of gas feed drying comprises that the temperature is 20-50℃, the pressure is 0.3-2 MPa, the volume space velocity of the gas feed is 500-3000 h -1 .

[0049] According to a preferred embodiment of the present application, the desiccants filled in the liquid feed drying regeneration unit and the gas feed drying regeneration unit are each independently molecular sieve desiccants, preferably at least one of 3A molecular sieve desiccants, 4A molecular sieve desiccants, 5A molecular sieve desiccants and 13X molecular sieve desiccants.

[0050] The second aspect of the present application provides an alkane aromatization system, such as Figure 1As shown, the system comprises an aromatization reaction unit 400, a product fractionation unit 500 and an aromatic hydrocarbon extraction unit 600 connected in series, and a liquid feed drying and regeneration unit 200 and a gas feed drying and regeneration unit 300 connected with the inlet of the aromatization reaction unit 400 respectively;

[0051] The liquid feed drying and regeneration unit 200 is provided with a liquid regenerant supply pipeline for providing a material containing C6-C7 alkanes to the liquid feed drying and regeneration unit 200 to perform first regeneration on the liquid feed drying and regeneration unit 200.

[0052] The gas feed drying and regeneration unit 300 is provided with a gas regenerant supply pipeline for providing hydrogen-rich gas to the gas feed drying and regeneration unit 300 to perform second regeneration on the gas feed drying and regeneration unit 300.

[0053] According to the system provided by the present application, the selection range of the material containing C6-C7 alkanes and the hydrogen-rich gas can be as described in the first aspect, which will not be repeated here.

[0054] According to a preferred embodiment of the present application, the liquid material outlet of the liquid feed drying and regeneration unit 200 is connected with the inlet of the liquid feed drying and regeneration unit 200 through a liquid regenerant supply pipeline, so that at least part of the liquid regenerant is provided by the liquid material obtained by drying the liquid feed drying and regeneration unit.

[0055] According to a preferred embodiment of the present application, the gas phase outlet of the product fractionation unit 500 is connected with the inlet of the gas feed drying and regeneration unit 300 through a gas regenerant supply pipeline, so that at least part of the gas regenerant is provided by the hydrogen-rich gas obtained by fractionation after the alkanes aromatization reaction.

[0056] According to a preferred embodiment of the present application, the liquid feed drying and regeneration unit 200 comprises at least two dryers connected in series and / or in parallel; the gas feed drying and regeneration unit 300 comprises at least two dryers connected in series and / or in parallel.

[0057] Preferably, the connection relationship of the at least two dryers of the liquid feed drying and regeneration unit 200 is such that at least one dryer of the liquid feed drying and regeneration unit 200 performs regeneration, and the other dryers are used for drying the liquid feed of the alkanes aromatization reaction.

[0058] Preferably, the connection relationship of the at least two dryers of the gas feed drying and regeneration unit 300 is such that at least one dryer of the gas feed drying and regeneration unit 300 performs regeneration, and the other dryers are used for drying the gas feed of the alkanes aromatization reaction.

[0059] According to a preferred embodiment of the present application, the liquid feed drying and regeneration unit 200 further comprises pipelines and valves, and the pipelines and valves are arranged such that the preceding dryer and the subsequent dryer in the liquid feed drying and regeneration unit 200 can be changed in the flow direction and can meet the cut-in and cut-out in the system.

[0060] According to a preferred embodiment of the present application, the gas feed drying and regeneration unit 300 further comprises pipelines and valves, and the pipelines and valves are arranged such that the preceding dryer and the subsequent dryer in the gas feed drying and regeneration unit 300 can be changed in the flow direction and can meet the cut-in and cut-out in the system.

[0061] According to a preferred embodiment of the present application, the system further comprises a liquid regenerant heater 238 and a first cooling separator 240, the liquid regenerant heater 238 is used for heating the liquid regenerant, and the first cooling separator 240 is used for cooling and separating the liquid regenerant after use to realize the recycling of the liquid regenerant.

[0062] According to a preferred embodiment of the present application, the system further comprises a gas regenerant heater 338 and a second cooling separator 340, the gas regenerant heater 338 is used for heating the gas regenerant, and the second cooling separator 340 is used for cooling and separating the gas regenerant after use to realize the recycling of the gas regenerant.

[0063] The first cooling separator 240 and the second cooling separator 340 are not particularly limited in the present application, and can be various cooling separators commonly used in the art, as long as the separation of the regenerant and water can be realized.

[0064] The liquid regenerant heater 238 and the gas regenerant heater 338 are not particularly limited in the present application, and can be various heaters commonly used in the art, as long as the regenerant can be heated to the required temperature under the regeneration condition.

[0065] According to a preferred embodiment of the present application, the system further comprises a desulfurization unit 100 for removing sulfur from the liquid feed. The outlet of the desulfurization unit 100 is in communication with the inlet of the liquid feed drying regeneration unit 200. The desulfurization unit 100 can be any device conventionally used in the art capable of reducing the S content of the feedstock.

[0066] According to the system provided by the present application, specifically, the liquid feed rich in C6-C7 alkane enters the desulfurization unit 100, and the feed is deeply desulfurized in the sulfur adsorption and conversion reactor of the desulfurization unit, so that the sulfur content of the feed is less than 0.1 ppm, and then the product enters the liquid feed drying regeneration unit 200, and the material passes from bottom to top. At the same time, the hydrogen-rich gas enters the gas drying unit 300. The dried liquid feed can be taken out a small part to circulate into the liquid feed drying regeneration unit 200, as the liquid regenerant of the liquid feed drying regeneration unit to regenerate the dryer under the regeneration operating condition; the remaining liquid material is mixed with the dried gas, and then enters the alkane aromatization reaction unit 400, and the alkane conversion reaction is carried out in the aromatization reaction unit 400 to generate benzene, toluene and other light aromatic hydrocarbons. The product after the aromatization reaction is discharged, and then enters the product fractionation unit 500. The product fractionation unit 500 generally includes a high-pressure gas-liquid separator, a stabilizing tower, a de-pentane tower, a reflux tank and the like. The gas separated by the high-pressure gas-liquid separator is mainly composed of hydrogen, and is discharged from the product fractionation unit, and then can be further used in multiple ways, part of which can enter the gas feed drying regeneration unit 300 as the regenerant of the gas feed drying regeneration unit to regenerate a certain dryer under the regeneration operating condition; another part is circulated in the aromatization reaction system, is pressurized by a compressor and then enters a running dryer of the gas feed drying regeneration unit 300 to dry the gas feed under the drying operating condition, and the dried gas is mixed with the aromatization reaction feed to provide a hydrogen source for the alkane aromatization reaction; the other excess gas is discharged to the outside of the device to provide a hydrogen source for other devices. The liquid product separated by the product fractionation unit enters the aromatic extraction unit 600, and the aromatic extraction unit 600 is used to obtain aromatic products and non-aromatic components (aromatic raffinate) after the aromatic extraction, wherein the aromatic products are discharged from the device, and the non-aromatic components can be partially or entirely returned to the aromatization reaction feed tank to be mixed with the reaction material as the liquid feed for further reaction; or can be discharged from the device as a gasoline blending component. The regenerant discharged from the liquid feed drying regeneration unit during regeneration and after regeneration is discharged to the raw material tank. The liquid feed desulfurization unit 100 includes a first sulfur adsorption reactor, a sulfur conversion reactor and a second sulfur adsorption reactor, and the deep desulfurization effect is achieved through the process of sulfur adsorption-conversion-adsorption again, so that the sulfur content in the liquid feed is less than 0.1 ppm. The liquid feed drying regeneration unit 200 and the gas feed drying regeneration unit 300 at least include two dryers, which can be connected in series or in parallel, can realize the drying and regeneration operation of the dryers at the same time, and can also realize the conversion of the front and rear dryers. For details, see Figure 2 and Figure 3 . The aromatization reaction unit 400 is generally composed of four to six reactors connected in series, and an intermediate heater is arranged between every two reactors to compensate for the endothermic of the alkane reforming reaction.

[0067] Figure 2 In this system, the first liquid feed dryer 201 serves as a pre-dryer, and the second liquid feed dryer 202 serves as a post-dryer to dry the liquid feed. The liquid feed enters the first liquid feed dryer 201 from bottom to top via pipelines 2, 203, valves 205 and 207, then flows through pipelines 209, 211, 213, and 215 to pipeline 208, entering the second liquid feed dryer 202. Finally, it exits through pipelines 210, 222, 224, and 226 to pipeline 4, draining into the feed buffer tank. Simultaneously, valve 219 is opened, valve 220 and other valves are closed, and the sample measured by the humidity analyzer 235 originates from the outlet of the first liquid feed dryer 201. When the humidity analyzer data does not meet the required specifications, it indicates that the first liquid feed dryer 201 needs regeneration. When the first liquid feed dryer 201 needs regeneration or is scheduled for regeneration, it is isolated and regenerated. The specific operation is as follows: Open the inlet valve 206 and outlet valve 224 of the second liquid feed dryer 202; open the inlet valve 220 of the second liquid feed dryer 202 outlet to the humidity analyzer 235; close the inlet valve 219 of the first liquid feed dryer 201 outlet to the humidity analyzer 235; close the inlet valve 205 of the first liquid feed dryer 201; close the crossover valve 213 of the first liquid feed dryer 201 to the second liquid feed dryer 202; isolate the first liquid feed dryer 201; and allow the liquid feed to enter the second liquid feed dryer 202 from bottom to top via pipeline 2, pipeline 204, valve 206, and pipeline 208, and then from the dryer outlet via pipeline 210, pipeline 222, valve 224, and pipeline 226 to pipeline 4 into the feed buffer tank. After the first liquid feed dryer 201 is depressurized, valve 227 is opened, allowing the dried feed from the feed buffer tank or from... Figure 1The dried product of the liquid feed drying regeneration unit 200 is passed through line 237, liquid regenerant heater 238, heated, then through line 239, line 229, valve 227, line 209 into the first liquid feed dryer 201, valve 231 opened, the regenerant is passed from the first liquid feed dryer 201 outlet through line 207, valve 231, line 233, line 236, then through the first cooling separator 240, cooled, separated and passed through line 241 to the feed tank. After the heat cycle regeneration for a certain time, when the water is discharged from the molecular sieve in the dryer, the heater is stopped, the regenerant continues to regenerate the cycle of the dryer, when the temperature of the dryer is reduced to 60°C, the regenerant feeding is stopped, and the regenerant in the first liquid feed dryer 201 is discharged. Then the valve 214 in the cross line between the second liquid feed dryer 202 and the first liquid feed dryer 201 is opened, the liquid material from the outlet of the second liquid feed dryer 202 is passed through line 212, valve 214, line 216 into the first liquid feed dryer 201, when the first liquid feed dryer 201 is full of liquid, valve 224 is closed, valve 223 is opened, the drying process is set to the second liquid feed dryer 202 as the front dryer, the first liquid feed dryer 201 as the rear dryer. When the data analyzed by the humidity analyzer does not meet the index requirements, it means that the second liquid feed dryer 202 needs to be regenerated. As described in the previous steps, isolate the second liquid feed dryer 202, regenerate the second liquid feed dryer 202, and then put it into the drying system after regeneration. In this way, the first liquid feed dryer 201 and the second liquid feed dryer 202 are alternately regenerated and put into the drying system after regeneration.

[0068] Figure 3In this system, the first gas feed dryer 301 serves as a pre-dryer, and the second gas feed dryer 302 serves as a post-dryer to dry the gas feed. The gas feed enters the first gas feed dryer 301 from bottom to top via pipelines 3, 303, valves 305 and 307, then flows through pipelines 309, 311, 313, and 315 to pipeline 308, entering the second gas feed dryer 302. Finally, it exits through pipelines 310, 322, 324, and 326 to pipeline 5, exiting into the feed buffer tank. Simultaneously, valve 319 is opened, valve 320 and other valves are closed, and the sample measured by the humidity analyzer 335 originates from the outlet of the first gas feed dryer 301. When the humidity analyzer data does not meet the required specifications, it indicates that the first gas feed dryer 301 needs regeneration. When the first gas feed dryer 301 needs regeneration or is scheduled for regeneration, it is isolated and regenerated. The specific operation is as follows: Open the inlet valve 306 and outlet valve 324 of the second gas feed dryer 302; open the inlet valve 320 of the second gas feed dryer 302 outlet to the humidity analyzer 335; close the inlet valve 319 of the first gas feed dryer 301 outlet to the humidity analyzer 335; close the inlet valve 305 of the first gas feed dryer 301; close the crossover valve 313 of the first gas feed dryer 301 to the second gas feed dryer 302; isolate the first gas feed dryer 301; and allow gas to enter the second gas feed dryer 302 from bottom to top via pipeline 3, pipeline 304, valve 306, and pipeline 308, then from the dryer outlet via pipeline 310, pipeline 322, valve 324, and pipeline 326 to pipeline 5 into the feed buffer tank. After the first gas feed dryer 301 is depressurized, valve 327 is opened, and the gas from... Figure 1The part of the circulating hydrogen gas of the product fractionation unit 500 is used as the gas regenerant, heated by the gas regenerant heater 338 through the pipeline 337, then enters the first gas feed dryer 301 through the pipeline 329, the valve 327, the pipeline 309, the valve 331 is opened, the regenerant is discharged from the first gas feed dryer 301 outlet through the pipeline 307, the valve 331, the pipeline 333, the pipeline 336, then cooled by the second cooling separator 340, and discharged to the outside of the device through the pipeline 341 for use by other devices after cooling and separation. After a certain time of heat circulation regeneration, after the water is discharged from the molecular sieve in the dryer, the heater is stopped, the regenerant continues to regenerate the dryer, and when the temperature of the dryer decreases to 50°C, the regenerant feeding of the first gas feed dryer 301 is stopped, and the regenerant of the first gas feed dryer 301 is discharged. Then the valve 314 between the second gas feed dryer 302 and the first gas feed dryer 301 is opened, and the gas material in the second gas feed dryer 302 outlet passes through the pipeline 312, the valve 314, the pipeline 316 to enter the first gas feed dryer 301, and when the first gas feed dryer 301 is full of gas, the valve 324 is closed and the valve 323 is opened, and the drying process is set to the second gas feed dryer 302 as the front dryer and the first gas feed dryer 301 as the rear dryer. When the humidity analyzer analyzes the data that does not meet the index requirements, it indicates that the second gas feed dryer 302 needs to be regenerated. As described above, the second gas feed dryer 302 is isolated, regenerated, and then put into the drying system. In this way, the first gas feed dryer 301 and the second gas feed dryer 302 are alternately regenerated and then put into the drying system for use.

[0069] In the present application, unless otherwise specified, the percentage content refers to the mass percentage content.

[0070] The present application will be further described by examples, but the present application is not limited thereto.

[0071] Example 1

[0072] In the fixed bed reaction device, the material 1 rich in C6 alkanes is used as the liquid regenerant, and its composition is shown in Table 1. The reaction of the liquid regenerant on the dried 5A molecular sieve is investigated, the liquid feed mass space velocity is 1 h -1 , the reaction temperature is 200°C, and the reaction pressure is 0.5 MPa. The mass fraction of the product is shown in Table 1. The results show that the components in the liquid regenerant hardly react.

[0073] Example 2

[0074] According to the method of Example 1, except that the reaction temperature is 320°C. The mass fraction of each component of the product is shown in Table 1. The results show that the components in the liquid regenerant hardly react.

[0075] Example 3

[0076] The procedure of Example 1 was followed except that the reaction temperature was 350°C. A small amount of benzene in the liquid regenerant was hydrogenated, and other components were almost not reacted. Therefore, it is preferred to use a liquid regenerant with as low aromatic hydrocarbon content as possible, and the regeneration temperature is not higher than 350°C.

[0077] Table 1

[0078]

[0079] Example 4

[0080] In a fixed bed reactor, material 2 rich in C6 alkanes was used as the liquid regenerant. The composition of the liquid regenerant is shown in Table 2. The reaction of the liquid regenerant on dry 4A molecular sieve was investigated. The liquid feed mass space velocity was 0.5 h -1 , the reaction temperature was 280°C, and the reaction pressure was 0.5 MPa. The mass fraction of the products is shown in Table 2. The results show that the components in the liquid regenerant are almost not reacted.

[0081] Example 5

[0082] The procedure of Example 4 was followed except that the reaction pressure was 0.35 MPa. The mass fraction of the products is shown in Table 2. The results show that the components in the liquid regenerant are almost not reacted.

[0083] Table 2

[0084]

[0085]

[0086] Example 6

[0087] 10 g of dry 5A molecular sieve desiccant was weighed and treated with water to make the water absorption rate of the molecular sieve desiccant 15.5%, to obtain the molecular sieve desiccant to be regenerated.

[0088] The molecular sieve desiccant to be regenerated was loaded into a reactor, and material 2 (water content < 1 ppm) was used as the liquid regenerant for regeneration at a temperature of 250°C and a pressure of 0.5 MPa, with a feed mass space velocity of 1 h -1 , and a regeneration time of 4 hours. The regenerated molecular sieve desiccant was sealed and measured for water absorption, which was 0.2%. The water removal rate was 98.7%.

[0089] Examples 7-12

[0090] The procedure of Example 6 was followed except that the regeneration conditions were different. The regeneration conditions and results are shown in Table 3.

[0091] Table 3

[0092]

[0093] From the results of Table 3, it can be seen that using C6-rich alkane material as liquid regenerant, water in the molecular sieve desiccant can be effectively removed at a regeneration temperature of 200-320°C, with a water removal rate of more than 98%, and the regeneration effect is excellent. When the regeneration temperature is lower than 200°C, the regeneration effect is not ideal; when the regeneration temperature is greater than 320°C, water in the molecular sieve desiccant can be effectively removed, but high temperature can cause some components in the liquid regenerant to react, so it is more preferred that the regeneration temperature is 200-320°C, and in order to further optimize the regeneration efficiency, it is more preferred that the regeneration temperature is 250-320°C.

[0094] Example 13

[0095] 10 grams of dried 5A molecular sieve desiccant were weighed and subjected to water absorption treatment so that the water absorption rate of the molecular sieve desiccant was 15.5%, obtaining the molecular sieve desiccant to be regenerated.

[0096] The same liquid regenerant and regeneration conditions as in Example 6 were used for regeneration, and then the regenerated desiccant was subjected to water absorption treatment, and then the same raw materials and conditions were used for regeneration, and so on. The results are shown in Table 4. The results show that using liquid regenerant can repeatedly regenerate the desiccant and has good regeneration effect.

[0097] Table 4

[0098] Number of regeneration times 1st time 10th time 20th time Water absorption rate of desiccant before regeneration / % 15.5 13.8 16.7 Water absorption rate of desiccant after regeneration / % 0.2 0.1 0.2 Water removal rate / % 98.7 99.3 98.8

[0099] Example 14

[0100] 10 grams of dried 5A molecular sieve desiccant were weighed and subjected to water absorption treatment so that the water absorption rate of the molecular sieve desiccant was 15%, obtaining the molecular sieve desiccant to be regenerated.

[0101] The molecular sieve desiccant to be regenerated was loaded into a reactor, and hydrogen-rich gas was used as gaseous regenerant for regeneration of the desiccant, and the composition thereof was similar to that of the alkane aromatization reaction cycle hydrogen (see Table 5). The regeneration temperature was 280°C, the pressure was 0.5 MPa, the feed volume space velocity was 200 h -1 , the regeneration time was 4 hours, and the water absorption amount of the regenerated molecular sieve desiccant was 0.1% after sealing. The water removal rate was 99.3%.

[0102] Table 5

[0103]

[0104]

[0105] Example 15

[0106] This embodiment illustrates the method for regenerating the dryer and the alkane aromatization system described in this invention.

[0107] like Figure 1 As shown, a liquid feed rich in C6-C7 alkanes (its composition is shown in Table 6 below) enters the desulfurization unit 100. In the desulfurization unit, the feed undergoes deep desulfurization via a sulfur adsorption and conversion reactor until the sulfur content is below 0.1 ppm. The product then enters the liquid feed drying and regeneration unit 200 for liquid feed drying (conditions include: temperature 50℃, pressure 0.5 MPa, and mass hourly space velocity 4 h⁻¹). -1 The material passes through from bottom to top. Simultaneously, hydrogen-rich gas (its composition is shown in Table 7 below) enters the gas drying unit 300 for gas feed drying (temperature 40℃, pressure 0.6MPa, volumetric hourly space velocity 1500 h⁻¹). -1 A small portion of the dried liquid feed (water content 0.3 ppm) can be recycled into the liquid feed drying and regeneration unit 200, serving as the liquid regenerant for one of the dryers under regeneration operating conditions (including: temperature 280°C, pressure 0.5 MPa, mass hourly space velocity 1 h⁻¹). -1 The remaining liquid material is mixed with the dried gas (water content 0.5 ppm) and then enters the alkane aromatization reaction unit 400, where an alkane conversion reaction occurs to produce light aromatics such as benzene and toluene. The product after the aromatization reaction is discharged and then enters the product fractionation unit 500. The product fractionation unit 500 generally includes a high-pressure gas-liquid separator, a stabilizer, a depentanizer, and a reflux tank. The gas separated by the high-pressure gas-liquid separator is mainly composed of hydrogen and is discharged from the product fractionation unit. It can then be further used in multiple streams. A portion of this gas can be used as a regenerator in the gas feed drying and regeneration unit 300 to regenerate a dryer under regeneration operating conditions (including: temperature 250℃, pressure 0.5 MPa, volume hourly space velocity 300 h⁻¹). -1); another part is recycled in the aromatization reaction system, pressurized by a compressor and then enters the gas feed drying regeneration unit 300 in the running dryer, where the gas feed is dried under drying operation conditions, and the dried gas is mixed with the aromatization reaction feed to provide a hydrogen source for the alkanes aromatization reaction; the other excess gas is discharged outside the device to provide a hydrogen source for other devices. The liquid product separated by the product fractionation unit enters the aromatic extraction unit 600, and after aromatic extraction, the aromatic product and non-aromatic components (aromatic raffinate) are obtained, wherein the aromatic product is discharged from the device, and the non-aromatic components can be partially or completely returned to the aromatization reaction feed tank and mixed with the reaction material as liquid feed for further reaction; or can be discharged from the device as a gasoline blending component. The regenerant discharged from the liquid feed drying regeneration unit during regeneration and after regeneration is discharged to the raw material tank. The liquid feed drying regeneration unit 200 and the gas feed drying regeneration unit 300 at least include two dryers, which can be connected in series or in parallel, can realize simultaneous drying and regeneration operation of the dryers, and can also realize the conversion of the front and rear of the dryers. For details, see Figure 2 and Figure 3 .

[0108] Table 6

[0109] Component name Mass fraction of raw material component / % Isopentane 2.21 n-Pentane 4.37 2,2-Dimethylbutane 4.03 2,3-Dimethylbutane 4.56 2-Methylpentane 33.69 3-Methylpentane 23.51 n-Hexane 26.62 Methylcyclopentane 0.94 Benzene 0.07

[0110] Table 7

[0111] Component name Mass fraction of regenerant component / % [H2] 89.25 Methane 4.99 Ethane 2.56 Propane 1.89 Isobutane 0.77 n-Butane 0.54 Water 0.5 ppm

[0112] As can be seen from the embodiments of the present application, the liquid regenerant and the gas regenerant described in the present application are used to regenerate the liquid feed and the gas feed drying agent of the alkanes aromatization reaction, which has good regeneration effect, and according to Figures 1-3 It can be seen that this kind of regeneration method can realize continuous operation of simultaneous drying and regeneration, so that the drying feed can continuously and uninterruptedly enter the reaction system, and the liquid regenerant discharged during regeneration and after regeneration can be sent to the raw material tank area and recycled for reaction. The method provided by the present application is not only simple to operate, but also can realize continuous operation of simultaneous drying and regeneration, saving energy and reducing consumption.

[0113] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method of regenerating a dryer, characterized by, The method comprises: The method comprises: The liquid regenerant is the same as the liquid feed of the alkane aromatization reaction. At least part of the gas regenerant is provided by the hydrogen-rich gas obtained by fractionation after the alkane aromatization reaction.

2. The method of claim 1, wherein, The first regeneration condition includes: the regeneration temperature is 200-350℃, the regeneration pressure is 0.2-1MPa, the regeneration time is 2-20 hours, the liquid regenerant feeding mass space velocity is 0.1-3h -1 .

3. The method of claim 2, wherein, The first regeneration condition includes: the regeneration temperature is 250-320℃, the regeneration pressure is 0.4-0.6MPa, the regeneration time is 4-10 hours, the liquid regeneration agent feeding mass space velocity is 0.5-2 h -1 .

4. The method of claim 1, wherein, The second regeneration conditions include a regeneration temperature of 150 to 350 DEG C, a regeneration pressure of 0.3 to 2 MPa, a regeneration time of 2 to 20 hours, and a feed volume space velocity of a gas regeneration agent of 25 to 900 h -1 .

5. The method of claim 4, wherein, The second regeneration conditions include a regeneration temperature of 200-300°C, a regeneration pressure of 0.4-1 MPa, a regeneration time of 4-10 hours, and a feed volume space velocity of the gas regeneration agent of 100-600 h -1 .

6. The method of claim 1, wherein, The liquid regenerant is a liquid stream containing C6 and / or C7 paraffins.

7. The method of claim 6, wherein, The liquid regenerant is selected from at least one of light naphtha, reforming raffinate oil and Fischer-Tropsch generated oil containing C6 and / or C7 paraffins.

8. The method of claim 7, wherein, The C6 and / or C7 paraffins are selected from at least one of n-hexane, 2,2-dimethylbutane, 2,3-dimethylbutane, n-heptane, 2-methylpentane and 3-methylpentane.

9. The method of claim 1, wherein, At least part of the liquid regenerant is provided by the liquid material obtained by drying in the liquid feed drying regeneration unit.

10. The method of claim 9, wherein, The mass flow rate of the liquid regenerant is 5% to 30% of the mass flow rate of the liquid material.

11. The method of claim 10, wherein, The mass flow rate of the liquid regenerant is 10% to 20% of the mass flow rate of the liquid material.

12. The method of claim 1, wherein, The volume content of hydrogen in the gas regenerant is not less than 80%.

13. The method of claim 12, wherein, The volume content of hydrogen in the gas regenerant is not less than 85%.

14. The method according to any one of claims 1-13, wherein, The liquid feed drying regeneration unit comprises at least two dryers connected in series and / or in parallel; the gas feed drying regeneration unit comprises at least two dryers connected in series and / or in parallel.

15. The method of claim 14, wherein, At least one dryer in the liquid feed drying regeneration unit is regenerated, and the other dryers are used for drying the liquid feed of the alkane aromatization reaction.

16. The method of claim 15, wherein, The drying conditions include: temperature of 30-70℃, pressure of 0.2-1MPa, mass space velocity of 2-10h -1 .

17. The method of claim 16, wherein, The drying conditions include a pressure of 0.4-0.6 MPa.

18. The method of claim 14, wherein, At least one dryer in the gas feed drying regeneration unit is regenerated, and the other dryers are used for drying the gas feed of the alkane aromatization reaction.

19. The method of claim 18, wherein, The drying conditions include a temperature of 20-50°C, a pressure of 0.3-2 MPa, a gas feed volume space velocity of 500-3000 h -1 .

20. The method of claim 14, wherein, When the water content in the outlet material of the dryer of the liquid feed drying regeneration unit is above 1 ppm, the dryer is cut out of the system for the first regeneration; When the water content in the outlet material of the dryer of the gas feed drying regeneration unit is above 5 ppm, the dryer is cut out of the system for the second regeneration.

21. The method of claim 20, wherein, The method further comprises cutting the dryer after the first regeneration into the system and connecting it after the last dryer for drying the liquid feed of the alkane aromatization reaction.

22. The method of claim 20, wherein, The method further comprises cutting the dryer after the second regeneration into the system and connecting it after the last dryer for drying the gas feed of the alkane aromatization reaction.

23. The method of claim 14, wherein, The drying agents filled in the liquid feed drying regeneration unit and the gas feed drying regeneration unit are each independently a molecular sieve drying agent.

24. The method of claim 23, wherein, The drying agents filled in the liquid feed drying regeneration unit and the gas feed drying regeneration unit are each independently at least one of 3A molecular sieve drying agent, 4A molecular sieve drying agent, 5A molecular sieve drying agent and 13X molecular sieve drying agent.

25. An alkane aromatization system characterized by, The system comprises an aromatization reaction unit (400), a product fractionation unit (500) and an aromatic hydrocarbon extraction unit (600) connected in series, and a liquid feed drying and regeneration unit (200) and a gas feed drying and regeneration unit (300) respectively connected with the inlet of the aromatization reaction unit (400); The liquid feed drying and regeneration unit (200) is provided with a liquid regenerant supply pipeline for providing a material containing C6-C7 alkanes to the liquid feed drying and regeneration unit (200) to perform first regeneration on the liquid feed drying and regeneration unit (200); The gas feed drying and regeneration unit (300) is provided with a gas regenerant supply pipeline for providing hydrogen-rich gas to the gas feed drying and regeneration unit (300) to perform second regeneration on the gas feed drying and regeneration unit (300); The liquid material outlet of the liquid feed drying and regeneration unit (200) is connected with the inlet of the liquid feed drying and regeneration unit (200) through the liquid regenerant supply pipeline, so that at least part of the liquid regenerant is provided by the liquid material dried by the liquid feed drying and regeneration unit; The gas phase outlet of the product fractionation unit (500) is connected with the inlet of the gas feed drying and regeneration unit (300) through the gas regenerant supply pipeline, so that at least part of the gas regenerant is provided by the hydrogen-rich gas obtained after fractionation of the alkanes aromatization reaction.

26. The system of claim 25, wherein, The liquid feed drying and regeneration unit (200) comprises at least two dryers connected in series and / or in parallel; the gas feed drying and regeneration unit (300) comprises at least two dryers connected in series and / or in parallel.

27. The system of claim 26, wherein, The connection relationship of the at least two dryers of the liquid feed drying and regeneration unit (200) is such that at least one dryer of the liquid feed drying and regeneration unit (200) performs regeneration, and the other dryers are used for drying the liquid feed of the alkanes aromatization reaction.

28. The system of claim 26, wherein, The connection relationship of the at least two dryers of the gas feed drying and regeneration unit (300) is such that at least one dryer of the gas feed drying and regeneration unit (300) performs regeneration, and the other dryers are used for drying the gas feed of the alkanes aromatization reaction.

29. The system of any of claims 25-28, wherein, The system further comprises a liquid regenerant heater (238) for heating the liquid regenerant, and a first cooling separator (240) for cooling and separating the used liquid regenerant to realize recycling of the liquid regenerant.

30. The system of any of claims 25-28, wherein, The system further comprises a gas regenerant heater (338) for heating the gas regenerant, and a second cooling separator (340) for cooling and separating the used gas regenerant to realize recycling of the gas regenerant.

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