CN114832416A - Mixed aromatic hydrocarbon vacuum rectification system and method for producing durene - Google Patents
Mixed aromatic hydrocarbon vacuum rectification system and method for producing durene Download PDFInfo
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- B01D3/10—Vacuum distillation
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Abstract
The invention belongs to the technical field of chemical industry, and particularly relates to a mixed aromatic hydrocarbon vacuum rectification system and method for producing durene. The technical scheme is as follows: a mixed aromatic vacuum rectification system for producing durene comprises a light component removal tower and a heavy component removal tower, wherein a mixed aromatic stream inlet pipeline is connected to the light component removal tower, the top of the light component removal tower is connected with a first condensation pipeline, a gas phase outlet of the first condensation pipeline is connected with an ejector through a pipeline, and a liquid phase outlet of the first condensation pipeline is connected with a light component recovery pipeline; the heavy phase mixing pipeline is connected between the bottom of the light component removal tower and the heavy component removal tower, the top of the heavy component removal tower is connected with a second condensation pipeline, a gas phase outlet of the second condensation pipeline is connected with the ejector through a pipeline, a liquid phase outlet of the second condensation pipeline is connected with a tetramethylbenzene recovery pipeline, and the bottom of the heavy component removal tower is connected with the heavy phase pipeline. The invention provides a mixed aromatic vacuum rectification system and a method for producing durene.
Description
Technical Field
The invention belongs to the technical field of chemical industry, and particularly relates to a mixed aromatic hydrocarbon vacuum rectification system and method for producing durene.
Background
Durene is an important fine chemical raw material and can be used as an important raw material for medicines, powder coating flatting agents, dyes, pesticides, surfactants and the like. The main application of durene is to obtain the pyromellitic dianhydride after oxidation, and then to polymerize with diamine compound to obtain the polyimide engineering plastic with high temperature resistance and good insulating property, and the polyimide is an important material in high-tech industries such as microelectronics, spaceflight and military industry.
Durene is extracted from mixed aromatic hydrocarbon, the mixed aromatic hydrocarbon is a byproduct in the processing process of petroleum and coal, mainly comes from a catalytic reforming device of an oil refinery and a wide-cut catalytic reforming device of a terylene material factory, and a small part of durene comes from other production devices such as ethylene tar and coal high-temperature coking byproducts of ethylene device byproducts. The mixed aromatic hydrocarbon is complex in composition, the utilization rate of durene in the mixed aromatic hydrocarbon is not high, most of the mixed aromatic hydrocarbon is used as fuel, and precious resources are wasted. Therefore, how to purify and utilize durene still has very important practical significance.
The components of the mixed aromatic hydrocarbon are complex, the boiling points are close, the separation is difficult, the durene is extracted from the mixed aromatic hydrocarbon mainly by adopting an atmospheric distillation method and an extractive distillation method at present, the atmospheric distillation method not only needs more theoretical plates, but also has high energy consumption, more and more complex process technologies and large investment, the extractive distillation method has high operation cost, and the purity of the durene is difficult to meet the requirement.
The patent researches the extraction of durene components in mixed aromatic hydrocarbon, proposes to adopt a vacuum rectification method, utilizes the difference of the boiling points of all components to remove low-boiling-point substances and high-boiling-point substances in the mixed aromatic hydrocarbon to obtain mixed durene, and the mixed durene is used as a raw material for downstream crystallization separation of durene and other non-durene. The method has the advantages of short flow, high product purity, low energy consumption, simple operation, stable operation and good industrial prospect.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention aims to provide a vacuum distillation system and a vacuum distillation method for producing durene, wherein a low-boiling-point substance and a high-boiling-point substance in the mixed aromatic hydrocarbon are separated by a vacuum distillation method to obtain high-purity durene.
The technical scheme adopted by the invention is as follows:
a mixed aromatic vacuum rectification system for producing durene comprises a light component removal tower and a heavy component removal tower, wherein a mixed aromatic stream inlet pipeline is connected to the light component removal tower, the top of the light component removal tower is connected with a first condensation pipeline, a gas phase outlet of the first condensation pipeline is connected with an ejector through a pipeline, and a liquid phase outlet of the first condensation pipeline is connected with a light component recovery pipeline; the heavy phase mixing pipeline is connected between the bottom of the light component removal tower and the heavy component removal tower, the top of the heavy component removal tower is connected with a second condensation pipeline, a gas phase outlet of the second condensation pipeline is connected with the ejector through a pipeline, a liquid phase outlet of the second condensation pipeline is connected with a tetramethylbenzene recovery pipeline, and the bottom of the heavy component removal tower is connected with the heavy phase pipeline.
And feeding a mixed aromatic stream from the middle part of the light component removal tower, discharging a light component stream below C10 from the top of the light component removal tower, feeding a condensate stream passing through the first condensation pipeline into a light component recovery pipeline, recovering 98% of C6-C9 products, and feeding a non-condensable gas stream into an injector to be fed into a fuel gas pipe network. And C10 and C10+ heavy component streams at the bottom of the light component removal tower are extracted and sent to the heavy component removal tower, C10 and a trace amount of C10-streams are extracted from the top of the heavy component removal tower, and condensate streams passing through a second condensation pipeline are sent to a tetramethylbenzene recovery pipeline to recover 99.5 wt% of tetramethylbenzene products. And C11 and C12 heavy component streams at the bottom of the de-heavy tower are extracted and then return to an upstream reaction system for recycling.
The invention adopts the vacuum rectification operation of the light-removing tower and the heavy-removing tower, so that low-boiling-point substances and high-boiling-point substances can be respectively and fully separated, light components C6-C9 and heavy components C11 and C12 of mixed aromatic hydrocarbon are recovered, C5 and below enter a fuel gas pipe network for utilization, and simultaneously, mixed tetramethylbenzene is purified, thereby providing guarantee for the separation of durene by subsequent crystallization. The purity of the tetramethylbenzene in the rectification process is more than 99.5 percent, and the recovery rate is more than 99.9 percent; the purity of light components C6-C9 is more than 98 percent, and the recovery rate is more than 99.67 percent; the purities of the heavy components C11 and C12 are more than 99 percent, and the recovery rate is more than 73.5 percent. Compared with the prior durene production technology, the method adopts a vacuum rectification method to extract the durene from the mixed aromatic hydrocarbon, and has simple and feasible separation process and easy operation.
As a preferable scheme of the present invention, the first condensation pipeline includes a light component removal tower top condenser and a light component removal tower tail gas condenser, the light component removal tower top condenser is connected with the top of the light component removal tower through a pipeline, a gas phase outlet of the light component removal tower top condenser is connected with the light component removal tower tail gas condenser through a pipeline, a gas phase outlet of the light component removal tower tail gas condenser is connected with an ejector through a pipeline, and a liquid phase outlet of the light component removal tower top condenser and a liquid phase outlet of the light component removal tower tail gas condenser are both connected with the light component recovery pipeline through pipelines. And taking the light component stream below C10 out of the tower from the top of the light component removal tower, primarily condensing the light component stream in a condenser at the top of the light component removal tower, and feeding the condensed liquid stream into a light component recovery pipeline. After the non-condensable gas stream enters a condenser for tail gas of the light component removal tower for further condensation, the non-condensable gas is pressurized to 0.35MpaG by a fuel gas ejector and is sent to a fuel gas pipe network; the condensate stream enters a light component recovery line. The gas phase flow strand at the top of the light component removal tower is gradually cooled by sequentially adopting circulating hot water and circulating water with desalted water quality, and two-stage cooling is adopted to ensure that the circulating water side of the condenser does not generate scale due to overhigh temperature in the long-term operation process, so that the heat exchange efficiency of the condenser can be greatly improved.
As a preferable scheme of the invention, the light component recovery pipeline comprises a light component removal tower reflux tank, an outlet of the light component removal tower reflux tank is connected with a light component removal tower reflux pump through a pipeline, and an outlet of the light component removal tower reflux pump is connected with a light component storage tank for storing products C6-C9 through a pipeline. And the condensed fluid stream passing through the condenser at the top of the light component removal tower enters a reflux tank of the light component removal tower, the non-condensable gas stream enters a condenser at the tail gas of the light component removal tower for further condensation, and the condensed fluid stream passing through the condenser at the tail gas of the light component removal tower also enters the reflux tank of the light component removal tower. After the condensate flow is pressurized by a light component removal tower reflux pump, 98 percent of C6-C9 products are extracted and sent to a light component storage tank for storage.
As a preferable scheme of the invention, a light component return pipe is connected between the outlet of the light component removal tower reflux pump and the tower top of the light component removal tower. And (3) dividing the condensate flow into two flows after being pressurized by a reflux pump of the light component removal tower, wherein one flow flows back to the top of the light component removal tower and is refined in a rectifying tower, so that the purity of the finally extracted C6-C9 product is improved.
As a preferable scheme of the invention, the second condensation pipeline comprises a heavy component removal tower top condenser and a heavy component removal tower tail gas condenser, the heavy component removal tower top condenser is connected with the tower top of the heavy component removal tower through a pipeline, a gas phase outlet of the heavy component removal tower top condenser is connected with the heavy component removal tower tail gas condenser through a pipeline, a gas phase outlet of the heavy component removal tower tail gas condenser is connected with the ejector through a pipeline, and a liquid phase outlet of the heavy component removal tower top condenser and a liquid phase outlet of the heavy component removal tower tail gas condenser are both connected with the tetramethylbenzene recovery pipeline through pipelines. And taking the C10 and trace C10-stream out of the top of the de-heaving tower, condensing the stream in a condenser at the top of the de-heaving tower, and feeding the condensate stream into a tetramethylbenzene recovery pipeline. After the non-condensable gas stream enters a tail gas condenser of the de-heavy column for further condensation, the non-condensable gas is sent to a fuel gas pipe network through a fuel gas ejector; the condensate stream enters a tetramethylbenzene recovery pipeline. The gas phase stream at the top of the de-heavy tower is gradually cooled by sequentially adopting circulating hot water and circulating water with desalted water quality, and two-stage cooling is adopted to ensure that the circulating water side of the condenser does not generate scale due to overhigh temperature in the long-term operation process, so that the heat exchange efficiency of the condenser can be greatly improved.
As a preferred scheme of the invention, the tetramethylbenzene recovery pipeline comprises a heavy component removal tower reflux tank, an outlet of the heavy component removal tower reflux tank is connected with a heavy component removal tower reflux pump through a pipeline, and an outlet of the heavy component removal tower reflux pump is connected with a tetramethylbenzene storage tank for storing tetramethylbenzene products through a pipeline. And the condensate flow passing through the tower top condenser of the de-weighting tower enters a reflux tank of the de-weighting tower, the non-condensable gas flow enters a tail gas condenser of the de-weighting tower for further condensation, and the condensate flow passing through the tail gas condenser of the de-weighting tower also enters the reflux tank of the de-weighting tower. After the condensate flow is pressurized by a reflux pump of the de-weighting tower, 99.5 wt% of tetramethylbenzene product is extracted and sent to a tetramethylbenzene storage tank.
As a preferable scheme of the invention, a tetramethylbenzene return pipe is connected between the outlet of the heavy component removal tower reflux pump and the tower top of the heavy component removal tower. And the condensed liquid flow is pressurized by a reflux pump of the de-heavy tower and then divided into two streams, wherein one stream flows back to the top of the de-heavy tower and is refined in a rectifying tower. The purity of the final extracted tetramethylbenzene product is improved.
In a preferred embodiment of the present invention, a light component removal column reboiling line is connected between the heavy phase mixing line and the bottom of the light component removal column, a light component removal column reboiler is connected to the light component removal column reboiling line, and a light component removal column still transfer pump is connected to the heavy phase mixing line. And C10 and C10+ heavy component streams at the bottom of the light component removal tower are divided into two streams, wherein one stream enters a reboiler of the light component removal tower and returns to the bottom of the light component removal tower after being partially gasified, and the other stream is delivered to the heavy component removal tower after being pressurized and extracted by a delivery pump at the bottom of the light component removal tower.
As a preferable scheme of the invention, a heavy-component removal tower reboiling pipeline is connected between the heavy-component removal pipeline and the tower bottom of the heavy-component removal tower, a heavy-component removal tower reboiler is connected on the heavy-component removal tower reboiling pipeline, and a heavy-component removal tower kettle delivery pump is connected on the heavy-component removal pipeline. And the C11 and C12 heavy component streams at the bottom of the de-heavy tower are divided into two streams, wherein one stream enters a reboiler of the de-heavy tower and returns to the tower kettle of the de-heavy tower after being partially gasified, and the other stream returns to an upstream reaction system for recycling after being pressurized and extracted by a delivery pump of the tower kettle of the de-heavy tower.
A vacuum rectification method of mixed aromatic hydrocarbon for producing durene comprises the following steps:
s1: feeding the mixed aromatic stream from the middle part of the light component removal tower, performing vacuum rectification by the light component removal tower, taking the light component stream with the boiling point of 132 ℃ and below C10 out of the light component removal tower from the top of the light component removal tower, condensing to 45 ℃ through a first condensation pipeline, and separating and storing C6-C9 products;
s2: introducing heavy components at the bottom of the light component removal tower into a heavy component removal tower for separation, performing vacuum rectification through the heavy component removal tower, condensing a stream at the top of the heavy component removal tower with the boiling point of 135 ℃ to 45 ℃ through a second condensation pipeline, and separating and storing a tetramethylbenzene product;
s3: separating heavy phase from the bottom of the de-heavy tower.
The invention has the beneficial effects that:
the invention adopts the vacuum rectification operation of the light-removing tower and the heavy-removing tower, so that low-boiling-point substances and high-boiling-point substances can be respectively and fully separated, light components C6-C9 and heavy components C11 and C12 in mixed aromatic hydrocarbon are recovered, C5 and below enter a fuel gas pipe network for utilization, and simultaneously, mixed tetramethylbenzene is purified, thereby providing guarantee for the subsequent crystallization and separation of durene. The purity of the tetramethylbenzene in the rectification process is more than 99.5 percent, and the recovery rate is more than 99.9 percent. Compared with the prior durene production technology, the method adopts a vacuum rectification method to extract the durene from the mixed aromatic hydrocarbon, and has simple and feasible separation process and easy operation.
Drawings
Fig. 1 is a schematic structural view of the present invention.
In the figure: 1-light component removal tower; 2-a de-weighting tower; 3-a first condensation line; 4-an ejector; 5-a light component recovery pipeline; 6-heavy phase mixing line; 7-a second condensation line; 8-tetramethylbenzene recovery pipeline; 9-heavy phase line; 11-mixed aromatics stream is passed into a pipeline; 31-a condenser at the top of the light component removal tower; 32-a condenser for tail gas of the light component removal tower; 51-a light component removal tower reflux tank; 52-a light ends removal column reflux pump; 53-light component storage tank; 54-light fraction reflux pipe; 61-reboiling pipeline of light component removal tower; 62-a light component removal tower reboiler; 63-a light component removal tower kettle conveying pump; 71-a tower top condenser of the de-heavy tower; 72-a de-weighting tower tail gas condenser; 81-a reflux tank of the de-heavy tower; 82-a de-weighting tower reflux pump; 83-tetramethylbenzene storage tank; 84-tetramethylbenzene reflux pipe; 91-reboiling pipeline of heavy component removing tower; 92-a de-heaving column reboiler; 93-heavy-component-removing tower kettle conveying pump.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
As shown in fig. 1, the mixed aromatic hydrocarbon vacuum rectification system for producing durene of the embodiment includes a light component removal tower 1 and a heavy component removal tower 2, the light component removal tower 1 is connected with a mixed aromatic hydrocarbon stream inlet pipeline 11, the top of the light component removal tower 1 is connected with a first condensation pipeline 3, a gas phase outlet of the first condensation pipeline 3 is connected with an ejector 4 through a pipeline, and a liquid phase outlet of the first condensation pipeline 3 is connected with a light component recovery pipeline 5; the heavy phase mixing pipeline 6 is connected between the bottom of the light component removal tower 1 and the heavy component removal tower 2, the top of the heavy component removal tower 2 is connected with a second condensation pipeline 7, a gas phase outlet of the second condensation pipeline 7 is connected with the ejector 4 through a pipeline, a liquid phase outlet of the second condensation pipeline 7 is connected with a tetramethylbenzene recovery pipeline 8, and the bottom of the heavy component removal tower 2 is connected with a heavy phase pipeline 9.
And (2) feeding a mixed aromatic stream from the middle part of the light component removal tower 1, discharging a light component stream below C10 from the top of the light component removal tower 1, feeding a condensate stream passing through the first condensation pipeline 3 into a light component recovery pipeline 5, recovering 98% of C6-C9 products, and feeding a non-condensable gas stream into an injector 4 and feeding the non-condensable gas stream into a fuel gas pipe network. And C10 and C10+ heavy component streams at the bottom of the light component removal tower 1 are extracted and sent to the heavy component removal tower 2, C10 and a trace amount of C10-streams are extracted from the top of the heavy component removal tower 2, and condensate streams passing through the second condensation pipeline 7 are sent to a tetramethylbenzene recovery pipeline 8 to recover 99.5 wt% of tetramethylbenzene products. C11 and C12 heavy component streams at the bottom of the de-heavy tower 2 are extracted and then return to an upstream reaction system for recycling.
The invention adopts the vacuum rectification operation of the light component removing tower 1 and the heavy component removing tower 2, so that low-boiling-point substances and high-boiling-point substances can be respectively and fully separated, light components C6-C9 and heavy components C11 and C12 of mixed aromatic hydrocarbon are recovered, C5 and below enter a fuel gas pipe network for utilization, and simultaneously, the mixed tetramethylbenzene is purified, thereby providing guarantee for the subsequent crystallization and separation of the durene. The purity of the tetramethylbenzene in the rectification process is more than 99.5 percent, and the recovery rate is more than 99.9 percent; the purity of light components C6-C9 is more than 98 percent, and the recovery rate is more than 99.67 percent; the purities of the heavy components C11 and C12 are more than 99 percent, and the recovery rate is more than 73.5 percent. Compared with the prior durene production technology, the method adopts a vacuum rectification method to extract the durene from the mixed aromatic hydrocarbon, and has simple and feasible separation process and easy operation.
Specifically, the first condensation pipeline 3 comprises a light component removal tower top condenser 31 and a light component removal tower tail gas condenser 32, the light component removal tower top condenser 31 is connected with the top of the light component removal tower 1 through a pipeline, a gas phase outlet of the light component removal tower top condenser 31 is connected with the light component removal tower tail gas condenser 32 through a pipeline, a gas phase outlet of the light component removal tower tail gas condenser 32 is connected with the ejector 4 through a pipeline, and a liquid phase outlet of the light component removal tower top condenser 31 and a liquid phase outlet of the light component removal tower tail gas condenser 32 are both connected with the light component recovery pipeline 5 through pipelines. And taking the light component stream below C10 out of the top of the light component removal tower 1, primarily condensing the light component stream in a condenser 31 at the top of the light component removal tower, and feeding the condensed liquid stream into a light component recovery pipeline 5. After the non-condensable gas stream enters a tail gas condenser 32 of the light component removal tower for further condensation, the non-condensable gas is pressurized to 0.35MpaG through a fuel gas ejector 4 and is sent to a fuel gas pipe network; the condensate stream enters a lights recovery line 5. The gas phase stream at the top of the light component removal tower 1 is sequentially cooled by circulating hot water and circulating water with desalted water quality, and two-stage cooling is adopted to ensure that the circulating water side of the condenser does not generate scale due to overhigh temperature in the long-term operation process, so that the heat exchange efficiency of the condenser can be greatly improved.
Specifically, the light component recovery pipeline 5 comprises a light component removal tower reflux tank 51, an outlet of the light component removal tower reflux tank 51 is connected with a light component removal tower reflux pump 52 through a pipeline, and an outlet of the light component removal tower reflux pump 52 is connected with a light component storage tank 53 for storing products C6-C9 through a pipeline. The condensed fluid stream passing through the condenser 31 at the top of the light component removal tower enters the reflux tank 51 of the light component removal tower, the non-condensed gas stream enters the condenser 32 at the tail gas of the light component removal tower for further condensation, and the condensed fluid stream passing through the condenser 32 at the tail gas of the light component removal tower also enters the reflux tank 51 of the light component removal tower. After the condensate flow is pressurized by a light component removal tower reflux pump 52, 98 percent of C6-C9 products are extracted and sent to a light component storage tank 53 for storage.
A light component return pipe 54 is connected between the outlet of the light component removal tower return pump 52 and the top of the light component removal tower 1. And the condensate flow is pressurized by a light component removal tower reflux pump 52 and then divided into two flows, wherein one flow flows back to the top of the light component removal tower 1 and is refined in a rectifying tower, so that the purity of the finally extracted C6-C9 product is improved.
Specifically, the second condensation pipeline 7 includes a heavy component removal tower top condenser 71 and a heavy component removal tower tail gas condenser 72, the heavy component removal tower top condenser 71 is connected with the top of the heavy component removal tower 2 through a pipeline, a gas phase outlet of the heavy component removal tower top condenser 71 is connected with the heavy component removal tower tail gas condenser 72 through a pipeline, a gas phase outlet of the heavy component removal tower tail gas condenser 72 is connected with the ejector 4 through a pipeline, and a liquid phase outlet of the heavy component removal tower top condenser 71 and a liquid phase outlet of the heavy component removal tower tail gas condenser 72 are both connected with the tetramethylbenzene recovery pipeline 8 through pipelines. The C10 and trace C10-stream are taken out of the top of the de-heaving tower 2 and condensed in a de-heaving tower overhead condenser 71, and the condensed liquid stream enters a tetramethylbenzene recovery pipeline 8. The non-condensable gas stream enters a tail gas condenser 72 of the de-heavy column for further condensation, and the non-condensable gas is sent to a fuel gas pipe network through a fuel gas ejector 4; the condensate stream enters the tetramethylbenzene recovery line 8. And the gas phase stream at the top of the de-heavy tower 2 is gradually cooled by sequentially adopting circulating hot water and circulating water with desalted water quality, and two-stage cooling is adopted to ensure that the circulating water side of the condenser is not scaled due to overhigh temperature in the long-term operation process, so that the heat exchange efficiency of the condenser can be greatly improved.
Specifically, the tetramethylbenzene recovery pipeline 8 comprises a heavy component removal tower reflux tank 81, an outlet of the heavy component removal tower reflux tank 81 is connected with a heavy component removal tower reflux pump 82 through a pipeline, and an outlet of the heavy component removal tower reflux pump 82 is connected with a tetramethylbenzene storage tank 83 for storing tetramethylbenzene products through a pipeline. The condensate stream passing through the top condenser 71 of the de-weighting tower enters a reflux tank 81 of the de-weighting tower, the non-condensable stream enters a tail gas condenser 72 of the de-weighting tower for further condensation, and the condensate stream passing through the tail gas condenser 72 of the de-weighting tower also enters the reflux tank 81 of the de-weighting tower. After the condensate flow is pressurized by a reflux pump 82 of the de-weighting tower, a tetramethylbenzene product with the weight percent of 99.5 percent is extracted and sent to a tetramethylbenzene storage tank 83.
And a tetramethylbenzene return pipe 84 is connected between the outlet of the heavy component removal tower reflux pump 82 and the top of the heavy component removal tower 2. The condensate flow is pressurized by a reflux pump 82 of the de-weighting tower and then divided into two flows, wherein one flow flows back to the top of the de-weighting tower 2 and is refined in a rectifying tower, and the purity of the final extracted tetramethylbenzene product is improved.
Furthermore, a light component removal tower reboiling pipeline 61 is connected between the heavy phase mixing pipeline 6 and the bottom of the light component removal tower 1, a light component removal tower reboiler 62 is connected on the light component removal tower reboiling pipeline 61, and a light component removal tower kettle conveying pump 63 is connected on the heavy phase mixing pipeline 6. And C10 and C10+ heavy component streams at the bottom of the light component removal tower 1 are divided into two streams, wherein one stream enters a reboiler 62 of the light component removal tower and returns to the bottom of the light component removal tower 1 after being partially gasified, and the other stream is pressurized and extracted by a conveying pump 63 at the bottom of the light component removal tower and then sent to the heavy component removal tower 2.
Furthermore, a heavy component removal column reboiling pipeline 91 is connected between the heavy phase pipeline 9 and the bottom of the heavy component removal column 2, a heavy component removal column reboiler 92 is connected on the heavy component removal column reboiling pipeline 91, and a heavy component removal column kettle conveying pump 93 is connected on the heavy phase pipeline 9. And C11 and C12 heavy component streams at the bottom of the de-heavy tower 2 are divided into two streams, wherein one stream enters a de-heavy tower reboiler 92 and returns to the tower kettle of the de-heavy tower 2 after being partially gasified, and the other stream returns to an upstream reaction system for recycling after being pressurized and extracted by a de-heavy tower kettle conveying pump 93.
A vacuum rectification method of mixed aromatic hydrocarbon for producing durene comprises the following steps:
s1: feeding a mixed aromatic stream from the middle part of a light component removal tower 1, performing vacuum rectification through the light component removal tower 1, taking a light component stream with a boiling point of 132 ℃ and below C10 out of the top of the light component removal tower 1, condensing to 45 ℃ through a first condensing pipeline 3, and separating and storing C6-C9 products;
s2: introducing heavy components at the bottom of the light component removal tower 1 into a heavy component removal tower 2 for separation, performing vacuum rectification through the heavy component removal tower 2, condensing the stream at the top of the heavy component removal tower 2 with the boiling point of 135 ℃ to 45 ℃ through a second condensation pipeline 7, and separating and storing a tetramethylbenzene product;
s3: the heavy phase is separated from the bottom of the de-heavy column 2.
The working process is as follows:
the mixed aromatic hydrocarbon stream is fed from the middle part of the light component removal tower 1, a light component stream (132 ℃) below C10 is taken out of the top of the light component removal tower 1 and is condensed in a condenser 31 at the top of the light component removal tower for the first time, and a condensate stream (100 ℃) enters a reflux tank 51 of the light component removal tower. After the non-condensable gas stream enters a tail gas condenser 32 of the light component removal tower for further condensation, the non-condensable gas (45 ℃) is pressurized to 0.35MpaG through a fuel gas ejector 4 and is sent to a fuel gas pipe network. The condensate stream passing through the tail gas condenser 32 of the lightness-removing column enters the reflux drum 51 of the lightness-removing column. The condensate flow is pressurized by a light component removal tower reflux pump 52 and then divided into two flows, wherein one flow flows back to the top of the light component removal tower 1 and is refined in a rectifying tower; the other stream is 98% of C6-C9 products and enters a light component storage tank 53. The C10 and C10+ heavy component streams at the bottom of the light component removal tower 1 are divided into two streams, wherein one stream (165 ℃) enters a light component removal tower reboiler 62 to be partially gasified and then returns to the bottom of the light component removal tower 1, and the other stream is pressurized and extracted by a light component removal tower bottom conveying pump 63 and then is sent to the heavy component removal tower 2.
The bottom stream of the light component removal tower 1 is fed from the middle part of the heavy component removal tower 2, C10 and a trace amount of C10-stream (135 ℃) are taken out of the top of the heavy component removal tower 2 and condensed in a tower top condenser 71 of the heavy component removal tower, and a condensate stream (100 ℃) enters a reflux tank 81 of the heavy component removal tower. The non-condensable gas stream enters a tail gas condenser 72 of the de-heavy column for further condensation, and the non-condensable gas (45 ℃) is sent to a fuel gas pipe network through a fuel gas ejector 4. The condensate stream passing through the de-heavies tail gas condenser 72 enters the de-heavies reflux drum 81. The condensate flow is pressurized by a de-weighting tower reflux pump 82 and then divided into two flows, wherein one flow flows back to the top of the de-weighting tower 2 and is refined in a rectifying tower; the other stream is 99.5 wt% of tetramethylbenzene product and is sent to a tetramethylbenzene storage tank 83. Splitting a C11 heavy component stream and a C12 heavy component stream at the bottom of the de-heaving tower 2 into two streams, wherein one stream (at 180 ℃) enters a de-heaving tower reboiler 92 and returns to the bottom of the de-heaving tower 2 after being partially gasified; the other flow is pressurized and extracted by a delivery pump 93 at the tower bottom of the de-weighting tower and then returned to the upstream reaction system for recycling.
It should be noted that:
the light component removing tower 1 and the heavy component removing tower 2 are both operated under negative pressure, the operating pressure range of the light component removing tower 1 is 30-40 kPa, the operating temperature range is 120-168 ℃, the operating pressure range of the heavy component removing tower 2 is 10-20 kPa, the operating temperature range is 130-190 ℃, the vacuum operation greatly reduces the rectification temperature and the generation of coked materials, and simultaneously, the product chromaticity is improved.
The temperature of the discharge stream (132 ℃) at the top of the light component removal tower 1 and the temperature of the discharge stream (135 ℃) at the top of the heavy component removal tower 2 are higher, the discharge stream at the top of the light component removal tower 1 and the discharge stream at the top of the heavy component removal tower 2 are condensed for the first time by utilizing circulating hot water of desalted water quality, the temperature of the discharge streams is reduced to 100 ℃, non-condensable gas is further condensed to 45 ℃ through circulating water, two-stage temperature reduction is adopted to ensure that the circulating water side of the condenser does not generate scaling due to overhigh temperature in the long-term operation process, and the heat exchange efficiency of the condenser can be greatly improved.
Because the vacuum rectification operation is adopted, the temperature of the tower bottom of the light component removing tower 1 and the heavy component removing tower 2 is lower than that of the normal pressure and pressure rectification, and the heating heat source of the light component removing tower reboiler 62 and the heavy component removing tower reboiler 92 can be saturated medium pressure steam, and the pressure range is 6-12 MpaG.
The light component removal tower 1 and the heavy component removal tower 2 both adopt packed towers, the packing is regular packing, the ripple directions of the upper part and the lower part of each packing unit are vertically arranged, and the gas phase is ensured to gradually change directions at the contact surfaces of the two adjacent packing units and smoothly flow through the packing towers. Meanwhile, at the joint part of the two layers of fillers, the flowing direction of the vapor phase is almost parallel to the vertical direction, and the flow velocity of the vapor phase is reduced by 25-50% relative to the inner part of the filler unit. The above two points reduce the pressure drop of the packing and the shearing force of the interaction between the vapor and liquid phases, which is important at the contact surface of the two-layer packing unit because the liquid film is thick and unstable. The reduced pressure drop and shear also reduces the potential for premature flooding at the junction of the two layers of packing, eliminating a local bottleneck.
The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.
Claims (10)
1. A mixed aromatic vacuum rectification system for producing durene is characterized in that: the device comprises a light component removal tower (1) and a heavy component removal tower (2), wherein a mixed aromatic stream introducing pipeline (11) is connected to the light component removal tower (1), the top of the light component removal tower (1) is connected with a first condensation pipeline (3), a gas phase outlet of the first condensation pipeline (3) is connected with an ejector (4) through a pipeline, and a liquid phase outlet of the first condensation pipeline (3) is connected with a light component recovery pipeline (5); the heavy phase mixed pipeline (6) is connected between the bottom of the light component removing tower (1) and the heavy component removing tower (2), the top of the heavy component removing tower (2) is connected with a second condensation pipeline (7), a gas phase outlet of the second condensation pipeline (7) is connected with the ejector (4) through a pipeline, a liquid phase outlet of the second condensation pipeline (7) is connected with a tetramethylbenzene recovery pipeline (8), and the bottom of the heavy component removing tower (2) is connected with a heavy phase pipeline (9).
2. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: the first condensation pipeline (3) comprises a light component removal tower top condenser (31) and a light component removal tower tail gas condenser (32), the light component removal tower top condenser (31) is connected with the top of the light component removal tower (1) through a pipeline, a gas phase outlet of the light component removal tower top condenser (31) is connected with the light component removal tower tail gas condenser (32) through a pipeline, a gas phase outlet of the light component removal tower tail gas condenser (32) is connected with the ejector (4) through a pipeline, and a liquid phase outlet of the light component removal tower top condenser (31) and a liquid phase outlet of the light component removal tower tail gas condenser (32) are connected with the light component recovery pipeline (5) through pipelines.
3. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: the light component recovery pipeline (5) comprises a light component removal tower reflux tank (51), the outlet of the light component removal tower reflux tank (51) is connected with a light component removal tower reflux pump (52) through a pipeline, and the outlet of the light component removal tower reflux pump (52) is connected with a light component storage tank (53) for storing C6-C9 products through a pipeline.
4. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: a light component return pipe (54) is connected between the outlet of the light component removal tower reflux pump (52) and the top of the light component removal tower (1).
5. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: second condensation pipeline (7) are including taking off heavy column top of the tower condenser (71) and taking off heavy column tail gas condenser (72), take off heavy column top of the tower condenser (71) and take off the top of the tower of heavy column (2) and pass through the pipe connection, the gaseous phase export that takes off heavy column top of the tower condenser (71) passes through the pipeline and is connected with taking off heavy column tail gas condenser (72), the gaseous phase export that takes off heavy column tail gas condenser (72) passes through the pipeline and is connected with sprayer (4), the liquid phase export of taking off heavy column top of the tower condenser (71) and the liquid phase export that takes off heavy column tail gas condenser (72) all are connected with tetramethylbenzene recovery pipeline (8) through the pipeline.
6. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: the tetramethylbenzene recovery pipeline (8) comprises a heavy component removal tower reflux tank (81), the outlet of the heavy component removal tower reflux tank (81) is connected with a heavy component removal tower reflux pump (82) through a pipeline, and the outlet of the heavy component removal tower reflux pump (82) is connected with a tetramethylbenzene storage tank (83) for storing tetramethylbenzene products through a pipeline.
7. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: and a tetramethylbenzene return pipe (84) is connected between the outlet of the heavy component removal tower reflux pump (82) and the top of the heavy component removal tower (2).
8. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: a light component removal tower reboiling pipeline (61) is connected between the heavy phase mixing pipeline (6) and the bottom of the light component removal tower (1), a light component removal tower reboiler (62) is connected to the light component removal tower reboiling pipeline (61), and a light component removal tower kettle conveying pump (63) is connected to the heavy phase mixing pipeline (6).
9. A mixed aromatic vacuum distillation system for the production of durene according to claim 1, wherein: a heavy component removal tower reboiling pipeline (91) is connected between the heavy phase pipeline (9) and the bottom of the heavy component removal tower (2), a heavy component removal tower reboiler (92) is connected on the heavy component removal tower reboiling pipeline (91), and a heavy component removal tower kettle conveying pump (93) is connected on the heavy phase pipeline (9).
10. A vacuum distillation process for mixed aromatics for the production of durene using the system of claim 1, wherein: the method comprises the following steps:
s1: sending a mixed aromatic stream from the middle part of a light component removal tower (1), performing vacuum rectification through the light component removal tower (1), taking a light component stream with a boiling point of 132 ℃ and below C10 out of the top of the light component removal tower (1), condensing to 45 ℃ through a first condensing pipeline (3), and separating and storing C6-C9 products;
s2: introducing heavy components at the bottom of the light component removal tower (1) into a heavy component removal tower (2) for separation, performing vacuum rectification through the heavy component removal tower (2), condensing a stream at the top of the heavy component removal tower (2) with a boiling point of 135 ℃ to 45 ℃ through a second condensation pipeline (7), and separating and storing a tetramethylbenzene product;
s3: separating heavy phase from the bottom of the heavy phase removal tower (2).
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1569781A (en) * | 2004-04-29 | 2005-01-26 | 天津天大天久科技股份有限公司 | Method and device for separating 1,2,3-trimethylbenzene |
| CN101250078A (en) * | 2008-04-01 | 2008-08-27 | 常熟市联邦化工有限公司 | Method for preparing mixed methylnaphthalene by using C+10 heavy aromatic hydrocarbon as raw material |
| CN105330507A (en) * | 2015-11-30 | 2016-02-17 | 中国海洋石油总公司 | Method for continuously extracting durene from MTG heavy petrol |
| CN212594064U (en) * | 2020-06-01 | 2021-02-26 | 山东明化新材料有限公司 | Durene rectification separator |
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2022
- 2022-04-01 CN CN202210337929.8A patent/CN114832416B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1569781A (en) * | 2004-04-29 | 2005-01-26 | 天津天大天久科技股份有限公司 | Method and device for separating 1,2,3-trimethylbenzene |
| CN101250078A (en) * | 2008-04-01 | 2008-08-27 | 常熟市联邦化工有限公司 | Method for preparing mixed methylnaphthalene by using C+10 heavy aromatic hydrocarbon as raw material |
| CN105330507A (en) * | 2015-11-30 | 2016-02-17 | 中国海洋石油总公司 | Method for continuously extracting durene from MTG heavy petrol |
| CN212594064U (en) * | 2020-06-01 | 2021-02-26 | 山东明化新材料有限公司 | Durene rectification separator |
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