阅读说明：本技术 生产无水氟化氢的工艺及装置 (Process and apparatus for producing anhydrous hydrogen fluoride ) 是由 李明 郑亚娟 张立维 黄相振 张超 侯超 李超 张飞翔 于 2020-11-26 设计创作，主要内容包括：本发明公开了一种生产无水氟化氢的工艺及装置,该工艺包括以下步骤：1)将萃取剂环己醇、含HF废水通入连续萃取塔中,通过萃取剂萃取含HF废水中HF,在连续萃取塔的塔顶采出萃取相,在连续萃取塔的塔底采出萃余相,萃取相的主要成分为HF；2)将萃取相通入粗馏塔中进行精馏分离,在粗馏塔的塔顶采出粗馏塔顶馏出物,在粗馏塔的塔底采出粗馏塔底物；3)将粗馏塔顶馏出物通入到精馏塔进行精馏分离,在精馏塔的塔顶采出精馏塔顶馏出物,精馏塔顶馏出物的主要成分为无水HF,在精馏塔的塔底采出精馏塔底物,精馏塔底物的主要成分为水。该工艺萃取操作后的萃取相和萃余相都极易处理,具有简单高效和绿色环保的优点,降低投资和运行成本。(The invention discloses a process and a device for producing anhydrous hydrogen fluoride, wherein the process comprises the following steps: 1) introducing cyclohexanol serving as an extractant and HF-containing wastewater into a continuous extraction tower, extracting HF in the HF-containing wastewater by using the extractant, extracting an extract phase at the top of the continuous extraction tower, and extracting a raffinate phase at the bottom of the continuous extraction tower, wherein the main component of the extract phase is HF; 2) introducing the extract phase into a coarse distillation tower for rectification separation, collecting the top distillate of the coarse distillation tower at the tower top of the coarse distillation tower, and collecting the bottom material of the coarse distillation tower at the tower bottom of the coarse distillation tower; 3) introducing the distillate from the top of the crude distillation tower into a rectifying tower for rectifying separation, collecting the distillate from the top of the rectifying tower, wherein the main component of the distillate from the top of the rectifying tower is anhydrous HF, and collecting the bottom of the rectifying tower from the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water. The extraction phase and the raffinate phase after the extraction operation of the process are easy to treat, have the advantages of simplicity, high efficiency, greenness and environmental protection, and reduce the investment and the operation cost.)

1. A process for producing anhydrous hydrogen fluoride comprising the steps of:

1) introducing an extractant cyclohexanol and HF-containing wastewater into a continuous extraction tower, extracting HF in the HF-containing wastewater by the extractant cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF;

2) introducing the extract phase into a crude distillation tower for rectification separation, collecting a crude distillation tower top distillate at the tower top of the crude distillation tower, wherein the main component of the crude distillation tower top distillate is HF, and collecting a crude distillation tower bottom at the tower bottom of the crude distillation tower, and the main component of the crude distillation tower bottom is cyclohexanol;

3) introducing the distillate from the top of the crude distillation tower into a rectifying tower for rectifying separation, collecting the distillate from the top of the rectifying tower, wherein the main component of the distillate from the top of the rectifying tower is anhydrous HF, and collecting the bottom of the rectifying tower from the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water.

2. The process for producing anhydrous hydrogen fluoride according to claim 1, wherein the operating temperature in the continuous extraction column in the step 1) is 30 ± 5 ℃ and the operating pressure is 1.01325 ± 0.2 bar.

3. The process for producing anhydrous hydrogen fluoride according to claim 1, wherein the feed temperature of the crude distillation column in the step 2) is 98 to 100 ℃, the overhead temperature of the crude distillation column is 30 to 34 ℃, and the bottom temperature of the crude distillation column is 109 to 111 ℃.

4. The process for producing anhydrous hydrogen fluoride according to claim 1, wherein the temperature of the top of the rectifying column in the step 3) is 19 to 21 ℃ and the temperature of the bottom of the rectifying column is 57 to 60 ℃.

5. The process for producing anhydrous hydrogen fluoride according to claim 1, wherein the step 1) is followed by a step m) of separating the raffinate phase in an HF recovery column, and recovering HF from the top of the HF recovery column, wherein the HF recovery column contains water as a main component, and HF recovery column bottoms is recovered from the bottom of the HF recovery column, and the HF recovery column bottoms contains H as a main component₂An azeotrope of O-HF.

6. The process for producing anhydrous hydrogen fluoride according to claim 5, wherein the feed temperature of the HF recovery column in the step m) is 98 to 100 ℃, the overhead temperature of the HF recovery column is 99 to 101 ℃, and the bottom temperature of the HF recovery column is 112 to 114 ℃.

7. The process for producing anhydrous hydrogen fluoride according to claim 5 or 6, further comprising a step n) of recycling HF from the HF recovery column bottoms to the continuous extraction column after the step m).

8. The process for producing anhydrous hydrogen fluoride according to claim 1, wherein the step 2) is followed by a step p) of feeding the crude distillation column bottoms into an extractant recovery column for separation, extracting the extractant recovery column overhead from the top of the extractant recovery column, wherein the extractant recovery column overhead mainly comprises H₂O in an extractant recovery towerThe bottom of the tower is extracted with extractant recovery tower bottom, and the main component of the extractant recovery tower bottom is cyclohexanol.

9. The process for producing anhydrous hydrogen fluoride according to claim 8, further comprising a step q) of recycling the extractant recovery column bottoms to the continuous extraction column for reuse after the step p).

10. The process for producing anhydrous hydrogen fluoride according to claim 1, further comprising a step r) of recycling the HF recovered by returning the bottom of the rectification column to the continuous extraction column after the step 3).

11. An apparatus for producing anhydrous hydrogen fluoride used in the process according to any one of claims 1 to 10, comprising:

the continuous extraction tower is used for introducing an extracting agent cyclohexanol and HF-containing wastewater, extracting HF in the HF-containing wastewater by the extracting agent cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF;

the rough distillation tower is connected with the continuous extraction tower and is used for introducing the extraction phase to carry out rectification separation, a top distillate of the rough distillation tower is extracted from the top of the rough distillation tower, the main component of the top distillate of the rough distillation tower is HF, a bottom material of the rough distillation tower is extracted from the bottom of the rough distillation tower, and the main component of the bottom material of the rough distillation tower is cyclohexanol;

the rectifying tower is connected with the crude distillation tower and is used for introducing the distillate at the top of the crude distillation tower for rectifying and separating, the distillate at the top of the rectifying tower is extracted at the top of the rectifying tower, the main component of the distillate at the top of the rectifying tower is anhydrous HF, the bottom of the rectifying tower is extracted at the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water.

12. The apparatus for producing anhydrous hydrogen fluoride according to claim 11, further comprising:

an HF recovery tower connected with the bottom of the continuous extraction tower and used for sending raffinate phase to be separated,extracting HF recovery tower overhead from the tower top of the HF recovery tower, wherein the main component of the HF recovery tower overhead is water, extracting HF recovery tower bottom from the tower bottom of the HF recovery tower, and the main component of the HF recovery tower bottom is H₂An azeotrope of O-HF.

13. The apparatus for producing anhydrous hydrogen fluoride according to claim 12, wherein the bottom of the HF recovery column is connected to an inlet of the continuous extraction column for returning the HF recovery column bottoms to the continuous extraction column to recycle HF.

14. The apparatus for producing anhydrous hydrogen fluoride according to claim 11, further comprising:

an extractant recovery tower connected with the bottom of the crude distillation tower, the extractant recovery tower is used for feeding the crude distillation tower substrate into the crude distillation tower for separation, extractant recovery tower top is extracted from the top of the extractant recovery tower, and the main component of the extractant recovery tower top is H₂And O, extracting the bottom of the extractant recovery tower from the bottom of the extractant recovery tower, wherein the bottom of the extractant recovery tower mainly contains cyclohexanol.

15. The apparatus for producing anhydrous hydrogen fluoride according to claim 14, wherein the bottom of the extractant recovery column is connected to the inlet of the continuous extraction column for recycling the extractant recovery column bottoms to the continuous extraction column.

16. The apparatus for producing anhydrous hydrogen fluoride according to claim 11, wherein the bottom of the rectifying column is connected to an inlet of the continuous extraction column for returning the rectifying column bottoms to the continuous extraction column for recycling HF.

Technical Field

The invention belongs to the technical field of recycling of HF-containing wastewater in the nuclear fuel industry, and particularly relates to a process and a device for producing anhydrous hydrogen fluoride.

Background

The nuclear fuel industry in China will generate a large amount of HF-containing wastewater of 36-40 wt% every year. The hydrofluoric acid waste liquid is treated by two methods mainly in the preparation process of the nuclear fuel, one is temporary storage treatment, but the hydrofluoric acid is used as a toxic and harmful chemical, and when the temporary storage amount of 40 wt% hydrofluoric acid is more than 500t, a major hazard source is formed; secondly, chemical treatment is adopted, mainly through chemical precipitation and coagulating sedimentation, fluoride ions in the wastewater are converted into fluorine-containing solid waste, the fluorine-containing solid waste is temporarily stored in a barrel, and the waste liquid is sent to a natural evaporation tank or is further treated to reach the standard and then is discharged. The treatment process generates a large amount of solid waste and causes waste of hydrogen fluoride resources. In the production process of the nuclear fuel industry, a large amount of AHF needs to be supplemented, the cost occupation ratio of the AHF in a nuclear fuel circulation system is up to more than 10%, and the production cost is greatly increased by supplementing fresh AHF.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a process and a device for producing anhydrous hydrogen fluoride aiming at the defects in the prior art, wherein an extract phase and a raffinate phase after extraction operation are easy to treat, so that the whole process flow has the advantages of simplicity, high efficiency, environmental protection and reduction of investment and operation cost.

The technical scheme adopted for solving the technical problem of the invention is to provide a process for producing anhydrous hydrogen fluoride, which comprises the following steps:

1) introducing an extractant cyclohexanol and HF-containing wastewater into a continuous extraction tower, extracting HF in the HF-containing wastewater by the extractant cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF; the extraction rate of HF extracted from the top of the continuous extraction tower is more than or equal to 98.9 percent; the content of HF in raffinate phase extracted from the bottom of the continuous extraction tower is less than or equal to 0.9 wt%, and the content of cyclohexanol is less than or equal to 9.8 wt%.

2) Introducing the extract phase into a crude distillation tower for rectification separation, collecting a crude distillation tower top distillate at the tower top of the crude distillation tower, wherein the main component of the crude distillation tower top distillate is HF, and collecting a crude distillation tower bottom at the tower bottom of the crude distillation tower, and the main component of the crude distillation tower bottom is cyclohexanol; the crude distillation tower overhead distillate is a light component, wherein the content of HF is more than 98.4 wt%, and the content of cyclohexanol is less than 1.5 wt%. The bottom material of the crude distillation tower is a heavy component, wherein the content of cyclohexanol is more than 78.9 wt%, and the content of HF is less than 3 wt%.

3) Introducing the distillate from the top of the crude distillation tower into a rectifying tower for rectifying separation, collecting the distillate from the top of the rectifying tower, wherein the main component of the distillate from the top of the rectifying tower is Anhydrous HF (AHF), and collecting the bottom of the rectifying tower from the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water, wherein the content of HF is less than 8.3 wt%. The distillate at the top of the rectifying tower is AHF product, the purity is more than 99.99 percent, and the index of the first-class product of the industrial anhydrous hydrogen fluoride (GB7746-2011) for preparing fluorine by electrolysis is met.

Preferably, the HF content in the HF-containing wastewater is 36-40 wt%.

Preferably, the operation temperature in the continuous extraction tower in the step 1) is 30 +/-5 ℃, and the operation pressure is 1.01325 +/-0.2 bar.

Preferably, the feeding temperature of the crude distillation tower in the step 2) is 98-100 ℃, the top temperature of the crude distillation tower is 30-34 ℃, and the bottom temperature of the crude distillation tower is 109-111 ℃.

Preferably, in the step 3), the temperature of the top of the rectifying tower is 19-21 ℃, and the temperature of the bottom of the rectifying tower is 57-60 ℃.

Preferably, the step 1) is followed by a step m) of sending the raffinate phase into an HF recovery tower for separation, and taking an HF recovery tower overhead out of the top of the HF recovery tower, wherein the main component of the HF recovery tower overhead is waterExtracting HF recovery tower bottom from the tower bottom of the HF recovery tower, wherein the HF recovery tower bottom mainly comprises H₂An azeotrope of O-HF.

Preferably, in the step m), the feeding temperature of the HF recovery tower is 98-100 ℃, the top temperature of the HF recovery tower is 99-101 ℃, and the bottom temperature of the HF recovery tower is 112-114 ℃.

Preferably, the step m) is followed by a step n) of returning the HF recovery column bottoms to the continuous extraction column for recycling HF.

Preferably, the method also comprises a step p) of sending the bottom material of the crude distillation tower into an extractant recovery tower for separation after the step 2), extracting the extractant recovery tower top material from the tower top of the extractant recovery tower, wherein the main component of the extractant recovery tower top material is H₂And O, extracting the bottom of the extractant recovery tower from the bottom of the extractant recovery tower, wherein the bottom of the extractant recovery tower mainly contains cyclohexanol.

Preferably, the step p) is followed by a step q) of recycling the extractant recovery bottom to the continuous extraction tower for reuse.

Preferably, the step 3) is followed by a step r) of returning the bottom of the rectification column to the continuous extraction column for recycling and recovering HF.

The invention also provides a device for producing anhydrous hydrogen fluoride, which comprises:

the continuous extraction tower is used for introducing an extracting agent cyclohexanol and HF-containing wastewater, extracting HF in the HF-containing wastewater by the extracting agent cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF;

the rough distillation tower is connected with the continuous extraction tower and is used for introducing the extraction phase to carry out rectification separation, a top distillate of the rough distillation tower is extracted from the top of the rough distillation tower, the main component of the top distillate of the rough distillation tower is HF, a bottom material of the rough distillation tower is extracted from the bottom of the rough distillation tower, and the main component of the bottom material of the rough distillation tower is cyclohexanol;

the rectifying tower is connected with the crude distillation tower and is used for introducing the distillate at the top of the crude distillation tower for rectifying and separating, the distillate at the top of the rectifying tower is extracted at the top of the rectifying tower, the main component of the distillate at the top of the rectifying tower is anhydrous HF, the bottom of the rectifying tower is extracted at the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises:

an HF recovery tower connected with the bottom of the continuous extraction tower, the HF recovery tower is used for sending the raffinate phase into the continuous extraction tower for separation, and an HF recovery tower top material is extracted from the tower top of the HF recovery tower, wherein the main component of the HF recovery tower top material is water, an HF recovery tower bottom material is extracted from the tower bottom of the HF recovery tower, and the main component of the HF recovery tower bottom material is H₂An azeotrope of O-HF.

Preferably, the bottom of the HF recovery column is connected to the inlet of the continuous extraction column for recycling HF by returning the HF recovery column bottoms to the continuous extraction column.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises:

an extractant recovery tower connected with the bottom of the crude distillation tower, the extractant recovery tower is used for feeding the crude distillation tower substrate into the crude distillation tower for separation, extractant recovery tower top is extracted from the top of the extractant recovery tower, and the main component of the extractant recovery tower top is H₂And O, extracting the bottom of the extractant recovery tower from the bottom of the extractant recovery tower, wherein the bottom of the extractant recovery tower mainly contains cyclohexanol.

Preferably, the bottom of the extractant recovery tower is connected with the inlet of the continuous extraction tower, and is used for recycling the bottom of the extractant recovery tower to the continuous extraction tower for reuse.

Preferably, the bottom of the rectification column is connected to the inlet of the continuous extraction column for recycling HF from the rectification column bottoms back to the continuous extraction column.

The invention provides a continuous production process for obtaining Anhydrous Hydrogen Fluoride (AHF) from HF-containing wastewater. The core of the invention is that cyclohexanol is introduced as an extractant, HF in HF-containing wastewater is transferred to an extraction phase through continuous extraction, and the extractant is removed by using a rectification process, so that AHF meeting the requirements of industrial first-grade products is obtained.

The process and the device for producing the anhydrous hydrogen fluoride are innovative in that: the characteristic of lower solubility of cyclohexanol in water and the characteristic of interaction of cyclohexanol and HF are utilized to develop a process method and a device for producing Anhydrous Hydrogen Fluoride (AHF) from HF-containing wastewater by extraction and rectification, and an extract phase and a raffinate phase after extraction operation are easy to treat, so that the whole process flow has the advantages of simplicity, high efficiency, greenness and environmental protection, and the investment and operation cost are reduced in the process of realizing the cyclic utilization of HF.

Drawings

FIG. 1 is a schematic configuration diagram of an apparatus for producing anhydrous hydrogen fluoride according to example 2 of the present invention.

In the figure: 1-a continuous extraction column; 2-a crude distillation column; 3-a rectifying tower; 4-HF recovery column; 5-extractant recovery column; 6-a first heat exchanger; 7-a second heat exchanger; 8-a third heat exchanger; 9-a fourth heat exchanger; 10-fifth heat exchanger.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Reference will now be made in detail to embodiments of the present patent, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present patent and are not to be construed as limiting the present patent.

Example 1

This example provides a process for producing anhydrous hydrogen fluoride, comprising the steps of:

1) introducing an extractant cyclohexanol and HF-containing wastewater into a continuous extraction tower, extracting HF in the HF-containing wastewater by the extractant cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF;

2) introducing the extract phase into a crude distillation tower for rectification separation, collecting a crude distillation tower top distillate at the tower top of the crude distillation tower, wherein the main component of the crude distillation tower top distillate is HF, and collecting a crude distillation tower bottom at the tower bottom of the crude distillation tower, and the main component of the crude distillation tower bottom is cyclohexanol;

3) introducing the distillate from the top of the crude distillation tower into a rectifying tower for rectifying separation, collecting the distillate from the top of the rectifying tower, wherein the main component of the distillate from the top of the rectifying tower is anhydrous HF, and collecting the bottom of the rectifying tower from the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water.

The embodiment also provides an apparatus for producing anhydrous hydrogen fluoride, which comprises:

the continuous extraction tower is used for introducing an extracting agent cyclohexanol and HF-containing wastewater, extracting HF in the HF-containing wastewater by the extracting agent cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower, and extracting a raffinate phase at the tower bottom of the continuous extraction tower, wherein the main component of the extract phase is HF;

the rough distillation tower is connected with the continuous extraction tower and is used for introducing the extraction phase to carry out rectification separation, a top distillate of the rough distillation tower is extracted from the top of the rough distillation tower, the main component of the top distillate of the rough distillation tower is HF, a bottom material of the rough distillation tower is extracted from the bottom of the rough distillation tower, and the main component of the bottom material of the rough distillation tower is cyclohexanol;

the rectifying tower is connected with the crude distillation tower and is used for introducing the distillate at the top of the crude distillation tower for rectifying and separating, the distillate at the top of the rectifying tower is extracted at the top of the rectifying tower, the main component of the distillate at the top of the rectifying tower is anhydrous HF, the bottom of the rectifying tower is extracted at the bottom of the rectifying tower, and the main component of the bottom of the rectifying tower is water.

The process and the device for producing anhydrous hydrogen fluoride are innovative in that: the characteristic of lower solubility of cyclohexanol in water and the characteristic of interaction of cyclohexanol and HF are utilized to develop a process method and a device for producing Anhydrous Hydrogen Fluoride (AHF) from HF-containing wastewater by extraction and rectification, and an extract phase and a raffinate phase after extraction operation are easy to treat, so that the whole process flow has the advantages of simplicity, high efficiency, greenness and environmental protection, and the investment and operation cost are reduced in the process of realizing the cyclic utilization of HF.

Example 2

As shown in fig. 1, the present embodiment provides an apparatus for producing anhydrous hydrogen fluoride, comprising:

the continuous extraction tower 1 is used for introducing an S2 stream extraction agent cyclohexanol and an S1 stream HF-containing wastewater, extracting HF in the HF-containing wastewater by the extraction agent cyclohexanol, collecting an S3 stream extraction phase at the top of the continuous extraction tower 1, and collecting an S4 stream raffinate phase at the bottom of the continuous extraction tower 1, wherein the main component of the extraction phase is HF;

the rough distillation tower 2 is connected with the continuous extraction tower 1, the rough distillation tower 2 is used for introducing an S3 stream extraction phase to perform rectification separation, an S5 stream rough distillation tower top distillate is collected at the tower top of the rough distillation tower 2, the main component of the rough distillation tower top distillate is HF, an S6 stream rough distillation tower bottom material is collected at the tower bottom of the rough distillation tower 2, and the main component of the rough distillation tower bottom material is cyclohexanol;

the rectifying tower 3 is connected with the crude distillation tower 2, the rectifying tower 3 is used for introducing the S5 stream crude distillation tower overhead to carry out rectification separation, an S7 stream rectifying tower overhead is collected at the tower top of the rectifying tower 3, the main component of the rectifying tower overhead is anhydrous HF, an S8 stream rectifying tower bottom is collected at the tower bottom of the rectifying tower 3, and the main component of the rectifying tower bottom is water.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises: the first heat exchanger 6 is provided on a connecting line between the continuous extraction column 1 and the crude distillation column 2. The first heat exchanger 6 is used for heating the material flowing from the continuous extraction column 1 to the crude distillation column 2.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises:

an HF recovery tower 4 connected with the bottom of the continuous extraction tower 1, wherein the HF recovery tower 4 is used for sending the raffinate phase of the S4 stream into the continuous extraction tower for separation, an S9 stream HF recovery tower overhead is produced at the top of the HF recovery tower 4, the main component of the HF recovery tower overhead is water, an S10 stream HF recovery tower bottom is produced at the bottom of the HF recovery tower 4, and the main component of the HF recovery tower bottom is H₂An azeotrope of O-HF.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises: and a third heat exchanger 8 disposed on a connecting line between the bottom of the continuous extraction column 1 and the HF recovery column 4. The third heat exchanger 8 is used for heating the material flowing from the continuous extraction column 1 to the HF recovery column 4.

Preferably, the bottom of the HF recovery column 4 is connected to the inlet of the continuous extraction column 1 for returning the HF recovery column bottoms to the continuous extraction column 1 for recycling HF.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises:

an extractant recovery tower 5 connected with the bottom of the crude distillation tower 2, wherein the extractant recovery tower 5 is used for feeding the S6 stream crude distillation tower bottom into the crude distillation tower for separation, an S11 stream extractant recovery tower top is extracted from the top of the extractant recovery tower 5, and the main component of the extractant recovery tower top is H₂And O, extracting an S12 stream extractant recovery tower bottom from the tower bottom of the extractant recovery tower 5, wherein the main component of the extractant recovery tower bottom is cyclohexanol.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises: and a fourth heat exchanger 9 disposed on a connecting line between the bottom of the crude distillation column 2 and the extractant recovery column 5. The fourth heat exchanger 9 is used for heating the material flowing from the crude distillation tower 2 to the extractant recovery tower 5.

Preferably, the bottom of the extractant recovery column 5 is connected to the inlet of the continuous extraction column 1 for recycling the extractant recovery column bottoms to the continuous extraction column 1 for reuse.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises: and a fifth heat exchanger 10 disposed on a connection line between the bottom of the extractant recovery column 5 and the inlet of the continuous extraction column 1. The fifth heat exchanger 10 is used for heating the material flowing from the extractant recovery column 5 to the continuous extraction column 1.

Preferably, the bottom of the rectification column 3 is connected to the inlet of the continuous extraction column 1 for recycling HF from the rectification column bottoms back to the continuous extraction column 1.

Preferably, the apparatus for producing anhydrous hydrogen fluoride further comprises:

and the second heat exchanger 7 is arranged on a connecting pipeline between the tower bottom of the rectifying tower 3 and the inlet of the continuous extraction tower 1. And a second heat exchanger 7 is also provided on the connecting line between the bottom of the HF recovery column 4 and the inlet of the continuous extraction column 1. The second heat exchanger 7 is used for heating the material flowing from the bottom of the HF recovery column 4 to the continuous extraction column 1.

The embodiment provides a process for producing anhydrous hydrogen fluoride by using the device, which comprises the following steps:

1) introducing an extractant cyclohexanol and HF-containing wastewater into a continuous extraction tower 1, extracting HF in the HF-containing wastewater by the extractant cyclohexanol, extracting an extract phase at the tower top of the continuous extraction tower 1, and extracting a raffinate phase at the tower bottom of the continuous extraction tower 1, wherein the main component of the extract phase is HF; the extraction rate of HF extracted from the top of the continuous extraction tower 1 is more than or equal to 98.9 percent; the content of HF in raffinate phase extracted from the bottom of the continuous extraction tower 1 is less than or equal to 0.9 wt%, and the content of cyclohexanol is less than or equal to 9.8 wt%.

2) Introducing the extract phase into a crude distillation tower 2 for rectification separation, collecting a crude distillation tower top distillate at the tower top of the crude distillation tower 2, wherein the main component of the crude distillation tower top distillate is HF, and collecting a crude distillation tower bottom at the tower bottom of the crude distillation tower 2, and the main component of the crude distillation tower bottom is cyclohexanol; the crude distillation tower overhead distillate is a light component, wherein the content of HF is more than 98.4 wt%, and the content of cyclohexanol is less than 1.5 wt%. The bottom material of the crude distillation tower is a heavy component, wherein the content of cyclohexanol is more than 78.9 wt%, and the content of HF is less than 3 wt%.

3) Introducing the distillate from the top of the crude distillation tower into a rectifying tower 3 for rectification separation, collecting the distillate from the top of the rectifying tower 3, wherein the distillate from the top of the rectifying tower mainly comprises Anhydrous HF (AHF), and collecting the bottom of the rectifying tower from the bottom of the rectifying tower 3, and the bottom of the rectifying tower mainly comprises water, wherein the content of HF is less than 8.3 wt%. The distillate at the top of the rectifying tower is AHF product, the purity is more than 99.99 percent, and the index of first-class products of industrial anhydrous hydrogen fluoride (GB 7746-.

Preferably, the HF content in the HF-containing wastewater is 36-40 wt%.

Preferably, the operation temperature in the continuous extraction tower 1 in the step 1) is 30 +/-5 ℃, and the operation pressure is 1.01325 +/-0.2 bar.

Preferably, in the step 2), the feeding temperature of the crude distillation tower 2 is 98-100 ℃, the top temperature of the crude distillation tower 2 is 30-34 ℃, and the bottom temperature of the crude distillation tower 2 is 109-111 ℃.

Preferably, in the step 3), the top temperature of the rectifying tower 3 is 19-21 ℃, and the bottom temperature of the rectifying tower 3 is 57-60 ℃.

Preferably, the step 1) is followed by a step m) of sending the raffinate phase into an HF recovery tower 4 for separation, and collecting HF recovery tower overhead at the tower top of the HF recovery tower 4, wherein the main component of the HF recovery tower overhead is water, the main component of the HF recovery tower bottom is collected at the tower bottom of the HF recovery tower 4, and the main component of the HF recovery tower bottom is H₂An azeotrope of O-HF.

Preferably, in the step m), the feeding temperature of the HF recovery tower 4 is 98-100 ℃, the top temperature of the HF recovery tower 4 is 99-101 ℃, and the bottom temperature of the HF recovery tower 4 is 112-114 ℃.

Preferably, the step m) is followed by a step n) of returning the HF recovery column bottoms to the continuous extraction column 1 for recycling HF.

Preferably, the method also comprises a step p) of sending the bottom material of the crude distillation tower into an extractant recovery tower 5 for separation after the step 2), extracting the extractant recovery tower top material from the tower top of the extractant recovery tower 5, wherein the main component of the extractant recovery tower top material is H₂And O, extracting the bottom of the extractant recovery tower 5 from the bottom of the extractant recovery tower, wherein the bottom of the extractant recovery tower mainly contains cyclohexanol.

Preferably, the step p) is followed by a step q) of recycling the extractant recovery bottoms to the continuous extraction column 1 for reuse.

Preferably, the step 3) is followed by a step r) of returning the bottom of the rectification column to the continuous extraction column 1 for recycling and recovering HF.

The process and the device for producing anhydrous hydrogen fluoride are innovative in that: the characteristic of lower solubility of cyclohexanol in water and the characteristic of interaction of cyclohexanol and HF are utilized to develop a process method and a device for producing Anhydrous Hydrogen Fluoride (AHF) from HF-containing wastewater by extraction and rectification, and an extract phase and a raffinate phase after extraction operation are easy to treat, so that the whole process flow has the advantages of simplicity, high efficiency, greenness and environmental protection, and the investment and operation cost are reduced in the process of realizing the cyclic utilization of HF.

Example 3

The technical scheme provided by the embodiment is as follows:

firstly, under the conditions of normal temperature and normal pressure, an extractant cyclohexanol and HF-containing waste water are in countercurrent contact in a continuously operated continuous extraction tower 1, wherein an extraction phase (an alcohol phase) contains 98.9 wt% (compared with a feeding amount) of HF and a small amount of water, and a raffinate phase (a water phase) contains 0.9 wt% of HF and 9.8 wt% of cyclohexanol. The raffinate phase enters an HF recovery tower 4 to further recover HF; introducing the extract phase into two crude distillation columns 2 and a rectifying column 3 which are operated in series for rectification, wherein the first crude distillation column 2 is mainly used for removing the extractant cyclohexanol, so that the extractant can be recycled; the second rectifying column 3 mainly processes H₂Separating O and HF, producing industrial AHF product at the top of the rectifying tower 3, and producing H at the bottom of the rectifying tower 3₂The O-HF azeotrope is recycled to the feed inlet of the continuous extraction column 1. The specific process is as follows:

this example provides a process for producing anhydrous hydrogen fluoride using the apparatus of example 2, comprising the steps of:

1) stream S1 was HF-containing wastewater having a treatment capacity of 666kg/hr, with an HF content of 37.2 wt%, a temperature of 30 ℃ and a pressure of 1.1 bar. Stream S2 was cyclohexanol as an extractant at a flow rate of 1000kg/hr, a temperature of 30 ℃ and a pressure of 1.1 bar. Introducing a stream S2 extractant cyclohexanol and a stream S1 HF-containing wastewater into a continuous extraction tower 1 for countercurrent contact, introducing the extractant cyclohexanol from the top of the continuous extraction tower 1, introducing the HF-containing wastewater from the bottom of the continuous extraction tower 1, and operating the continuous extraction tower 1 under normal pressure by adopting a sieve plate tower with 6 tower plates. Extracting HF in HF-containing wastewater by using an extractant cyclohexanol, and extracting a stream S3 extraction phase at the top of a continuous extraction tower 1, wherein the content of cyclohexanol is 922.0545kg/hr, the content of HF is 250.2546kg/hr, and the content of H is H₂O was 209.4855 kg/hr. The major component of the extract phase was HF, and 98.9 wt% of HF in the feed was extracted, wherein cyclohexanol content was about 66.7% (wt%), HF content was about 18.1 wt%, and H was present₂The O content was about 15.1 wt%. In the bottom extract phase (aqueous phase) of stream S4 taken from the continuous extraction column 1, H₂O253.4345 kg/hr, HF 2.8254kg/hr, cyclohexanol 27.9455kg/hr, H₂The content of O is more than 89.2 wt%, while the content of HF is less than 0.9 wt% and the content of cyclohexanol is less than 9.8 wt%. The HF content in the HF-containing wastewater is 36-40 wt%.

2) Heating the extract phase of the stream S3 by a first heat exchanger 6, raising the temperature to 100 ℃, introducing into a rough distillation tower 2 for rectification separation, and removing cyclohexanol, wherein the rough distillation tower 2 adopts a packed tower, the number of effective tower plates is 15, the position of a feed plate is 5, the reflux ratio is 2, the thermal load at the top of the rough distillation tower 2 is 843kW, and the thermal load at the bottom of the rough distillation tower 2 is 1868 kW. Withdrawing stream S5 at the top of crude distillation column 2 at 31.76 deg.C and 1.001bar pressure, wherein HF is 215.3199kg/hr and H is₂O is 0.0042kg/hr and cyclohexanol is 3.4888 kg/hr. The crude column overhead comprises a major amount of HF and a minor amount of water. Stream S6 crude distillation column bottoms is taken at the bottom of crude distillation column 2 at 109.7 deg.C under 1.015bar pressure, wherein cyclohexanol is 918.7112kg/hr, HF is 34.9801kg/hr, H₂O was 209.4958 kg/hr. The main component of the bottom of the crude distillation column is cyclohexanol, and also water and a small amount of HF. The crude distillation tower overhead distillate is a light component, wherein the content of HF is more than 98.4 wt%, and the content of cyclohexanol is less than 1.5 wt%. The bottom material of the crude distillation tower is a heavy component, wherein the content of cyclohexanol is more than 78.9 wt%, and the content of HF is less than 3 wt%.

3) Heating raffinate phase of the stream S4 to 99 ℃ through a third heat exchanger 8, feeding the raffinate phase into an HF recovery tower 4 for separation, wherein the HF recovery tower 4 adopts a packed tower, the number of effective tower plates is 15, the position of a feed plate is 7, the reflux ratio is 2, the top heat load of the HF recovery tower 4 is 1092kW, and the bottom heat load of the HF recovery tower 4 is 38 kW. Recovering overhead from HF recovering column 4 overhead stream S9HF at 98.7 deg.C under 1.001bar pressure, wherein HF is 4.79 × 10^-6kg/hr，H₂247.1kg/hr of O, 27.9kg/hr of cyclohexanol, and water as a main component of an overhead of the HF recovery column. Recovering bottoms of HF recovery column 4 column bottom stream S10HF at 112.2 deg.C under 1.015bar pressure, wherein cyclohexanol content is 2.85 × 10^-5kg/hr, HF 2.8kg/hr, H₂O is 6.3kg/hr, and the HF recovery column bottoms is composed mainly of H₂An azeotrope of O-HF.

4) And cooling the bottom of the recovery tower of the stream S10HF by a second heat exchanger 7 for 30 ℃, mixing the cooled bottom with HF-containing wastewater of the stream S1, and circularly entering an extraction tower to circularly recover HF so as to improve the recovery rate of HF in the whole process.

5) Introducing the stream S5 crude distillation column overhead into the fine distillation column at bubble pointRectifying and separating HF and H in a rectifying tower 3₂And O, the rectifying tower 3 adopts a packed tower, the number of effective tower plates is 5, the position of a feed plate is 3, the reflux ratio is 2, the heat load at the top of the tower is 839kW, and the heat load at the bottom of the tower is 4.53 kW. The temperature of the top of the rectifying tower 3 is 19-21 ℃, and the temperature of the bottom of the rectifying tower 3 is 57-60 ℃. Collecting the distillate at the top of the rectifying tower 3, wherein the distillate at the top of the rectifying tower mainly comprises Anhydrous HF (AHF), the temperature at the top of the rectifying tower 3 is 19.3 ℃, the pressure is 1.001bar, the HF in the distillate at the top of the rectifying tower is 214.9997kg/hr, and H is H₂The O and cyclohexanol contents were less than 0.0003 kg/hr. A stream S8 of distillation column bottoms is taken from the bottom of the distillation column 3 at a temperature of 57.8 deg.C and a pressure of 1.0050bar, wherein cyclohexanol is 3.4885kg/hr, HF is 0.3202kg/hr, H is₂O is 0.0042 kg/hr. The main component of the bottom of the rectification column is water, wherein the content of HF is less than 8.3 wt%. The distillate at the top of the rectifying tower is AHF product, the purity is more than 99.99 percent, and the index of the first-class product of the industrial anhydrous hydrogen fluoride (GB7746-2011) for preparing fluorine by electrolysis is met.

6) Cooling the bottom of the rectifying tower of the stream S8 to 30 ℃ through a second heat exchanger 7, mixing the bottom with HF-containing wastewater of the stream S1, and entering an extraction tower for recycling HF.

7) And heating the stream S6 to 98 ℃ through a fourth heat exchanger 9, feeding the stream S6 into an extractant recovery tower 5 for separation, wherein the extractant recovery tower 5 adopts a packed tower, the number of effective tower plates is 15, the position of a feed plate is 12, the reflux ratio is 1, the top heat load 865kW of the extractant recovery tower 5 is achieved, and the bottom heat load 986kW of the extractant recovery tower 5 is achieved. An overhead stream S11 of the extractant recovery tower 5 is an extractant recovery tower overhead, and the main component of the extractant recovery tower overhead is H₂O, temperature 96.2 ℃ and pressure 1.001 bar. The bottom of extractant recovery tower 5 is extracted to stream S12 extractant recovery tower bottom at 137.8 deg.C and 1.015bar, wherein cyclohexanol content is 918.3kg/hr, HF content is 34.8kg/hr, H content is H content₂O was 9.5 kg/hr. The main component of the bottom of the extractant recovery tower is cyclohexanol.

8) And recycling the bottom of the extractant recovery tower of the stream S12 to the continuous extraction tower 1 for reuse. And cooling the bottom of the extractant recovery tower of the stream S12 to 30 ℃ through a fifth heat exchanger 10, mixing the bottom with HF-containing wastewater of the stream S1, and feeding the mixture into a continuous extraction tower 1.

The process and the device for producing anhydrous hydrogen fluoride are innovative in that: the characteristic of lower solubility of cyclohexanol in water and the characteristic of interaction of cyclohexanol and HF are utilized to develop a process method and a device for producing Anhydrous Hydrogen Fluoride (AHF) from HF-containing wastewater by extraction and rectification, and an extract phase and a raffinate phase after extraction operation are easy to treat, so that the whole process flow has the advantages of simplicity, high efficiency, greenness and environmental protection, and the investment and operation cost are reduced in the process of realizing the cyclic utilization of HF.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.