CN116409751A - Hydrogen fluoride production method and system - Google Patents

Abstract

The present invention relates to the technical field of hydrogen fluoride preparation, in particular to a method and system for producing hydrogen fluoride, comprising the following steps: A) reacting fluorosilicic acid and first concentrated sulfuric acid in a main reaction zone to generate silicon tetrafluoride gas and sulfuric acid containing hydrogen fluoride solution; B) the silicon tetrafluoride gas is passed into the silicon tetrafluoride generation area; the sulfuric acid solution containing hydrogen fluoride is divided to form at least two paths for the preparation of hydrogen fluoride gas; wherein: the first part of the sulfuric acid solution containing hydrogen fluoride is passed through into the distillation area for separation, the separated hydrogen fluoride gas is passed into the hydrogen fluoride generation area to remove moisture, and the dried crude hydrogen fluoride gas is collected; the second part of sulfuric acid solution containing hydrogen fluoride and the second concentrated sulfuric acid are passed into the mixing area, and the The diluted sulfuric acid solution after mixing treatment is returned to the main reaction area. The invention directly parallels the sulfuric acid cycle treatment in the separation section, uses the sulfuric acid to treat the gas in each section, and improves the yield and purity of HF.

Description

A method and system for producing hydrogen fluoride

Technical Field

The present invention relates to the technical field of hydrogen fluoride preparation, and in particular to a method and system for producing hydrogen fluoride.

Background Art

The main reaction formula for preparing anhydrous hydrogen fluoride using the existing one-step method of fluorosilicic acid is shown in formula (1):

Concentrated fluorosilicic acid generates silicon tetrafluoride and hydrogen fluoride under the decomposition of concentrated sulfuric acid. The reaction principle is that concentrated fluorosilicic acid is thermally decomposed under the exothermic dilution of concentrated sulfuric acid. There are two main methods for separating silicon tetrafluoride and hydrogen fluoride in the hydrogen fluoride production system currently on the market: the first is that both the generated HF and _SiF4 are released from the reaction solution as gases, and the HF gas is subsequently separated from the mixed gas; the other is that _SiF4 is released from the solution as a gas while most of the HF is retained in the reaction solution, and the HF is subsequently separated from the sulfuric acid solution. In all of the above separation methods, part of the hydrogen fluoride escapes with silicon tetrafluoride and enters the back-end tail gas treatment system, and the purified tail gas still contains a certain amount of hydrogen tetrafluoride and hydrogen fluoride gas.

Hydrogen fluoride is a toxic gas. If it is not discharged without treatment, it will pollute the environment and cause harm to the human body. In addition, silicon tetrafluoride and hydrogen fluoride in the tail gas also have economic value. Direct discharge will lead to the loss of fluorine resources, thereby causing a waste of resources. The solution of the prior art is usually to wash the tail gas, so that silicon tetrafluoride in the tail gas can be converted into fluorosilicic acid as a raw material and circulated to the reaction end. Although this solution optimizes the utilization rate of fluorine resources to a certain extent, it does not directly solve the loss of hydrogen fluoride escape. For this reason, it is urgent to develop a production method that can effectively reduce the loss of hydrogen fluoride and improve the yield of hydrogen fluoride.

Summary of the invention

In view of this, the technical problem to be solved by the present invention is to provide a method and system for producing hydrogen fluoride, wherein the yield and purity of hydrogen fluoride are both high.

Another object of the present invention is to reduce energy consumption while reducing fluorine loss.

The present invention provides a method for producing hydrogen fluoride, comprising the following steps:

A) fluorosilicic acid and the first concentrated sulfuric acid react in a main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride;

B) the silicon tetrafluoride gas is passed into the silicon tetrafluoride generation zone;

The sulfuric acid solution containing hydrogen fluoride is split into at least two paths for preparing hydrogen fluoride gas; wherein:

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into the distillation zone for separation, passing the separated hydrogen fluoride gas into the hydrogen fluoride generation zone to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The second part of the sulfuric acid solution containing hydrogen fluoride is heated and introduced into the mixing zone with the second concentrated sulfuric acid, and the diluted sulfuric acid solution after the mixing treatment is recycled into the main reaction zone as a raw material.

Further, in step B), the mixing zone includes a silicon tetrafluoride production zone;

The second concentrated sulfuric acid flows through the silicon tetrafluoride production zone and is mixed with the second portion of the sulfuric acid solution containing hydrogen fluoride and then is recycled to the main reaction zone for drying and/or absorbing one or more gases in the silicon tetrafluoride production zone;

The temperature of the silicon tetrafluoride generation zone is 20-120°C.

Furthermore, in step B), after the distillation zone is separated, the process further comprises:

The distillation mother liquid separated in the distillation zone is stripped to obtain high-temperature hydrogen fluoride gas, which is then transported to the silicon tetrafluoride production zone.

Furthermore, in step B), after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas produced in the distillation process is transported to the hydrogen fluoride generation zone.

Furthermore, in step B), the mixing zone includes a silicon tetrafluoride production zone and a hydrogen fluoride recovery zone, respectively; the second concentrated sulfuric acid flows through the silicon tetrafluoride production zone and the hydrogen fluoride recovery zone in sequence, and is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery zone and then recycled to the main reaction zone for drying and/or absorbing one or more gases in the silicon tetrafluoride production zone and the hydrogen fluoride recovery zone;

The temperature of the silicon tetrafluoride generation zone is 20-120°C; the temperature of the hydrogen fluoride recovery zone is 100-200°C.

Furthermore, in step B), after the distillation zone is separated, the process further comprises:

Stripping the distillation mother liquid separated in the distillation zone to obtain high-temperature hydrogen fluoride gas and conveying it to the hydrogen fluoride recovery zone;

The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the silicon tetrafluoride production zone for absorption.

Furthermore, in step B), after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas produced during the distillation process is transported to the hydrogen fluoride recovery area.

Further, in step B), the mixing zone includes a silicon tetrafluoride generation zone, a hydrogen fluoride recovery zone and a hydrogen fluoride absorption zone, respectively; the second concentrated sulfuric acid flows through the silicon tetrafluoride generation zone and the hydrogen fluoride absorption zone simultaneously to form two parallel flow paths;

The sulfuric acid solution flowing out of the silicon tetrafluoride production zone is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery zone and then recycled to the main reaction zone for drying and/or absorbing one or more gases in the silicon tetrafluoride production zone and the hydrogen fluoride recovery zone;

The sulfuric acid solution flowing out of the hydrogen fluoride absorption zone is mixed with the sulfuric acid solution in the hydrogen fluoride generation zone and then recycled to the main reaction zone for drying and/or absorbing one or more gases in the hydrogen fluoride absorption zone and the hydrogen fluoride generation zone;

The temperature of the silicon tetrafluoride generation zone is 20-120°C; the temperature of the hydrogen fluoride recovery zone is 100-200°C; and the temperature of the hydrogen fluoride absorption zone is 10-140°C.

Furthermore, after the distillation zone is separated, it also includes:

Stripping the distillation mother liquid separated in the distillation zone to obtain high-temperature hydrogen fluoride gas and conveying it to the hydrogen fluoride recovery zone;

The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the hydrogen fluoride absorption zone for absorption.

Furthermore, in step B), after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas produced during the distillation process is transported to the hydrogen fluoride recovery area.

Furthermore, in step A), the mass concentration of the fluorosilicic acid in the main reaction zone is 30% to 55%, the mass concentration of the first concentrated sulfuric acid is 65% to 95%, and the reaction temperature is 80 to 130°C;

In step B), the mass concentration of the second concentrated sulfuric acid is 96-98%.

The present invention also provides a hydrogen fluoride production system, comprising:

A main reaction device, used for adding fluorosilicic acid and the first concentrated sulfuric acid for mixed reaction, and discharging gaseous products and liquid products; the main reaction device is provided with at least two liquid outlets;

A distillation device, used for separating hydrogen fluoride gas from part of the fluorine-containing sulfuric acid discharged from the main reaction device; the distillation device is connected to one of the liquid outlets of the main reaction device;

The mixing device includes a hydrogen fluoride generating device to prepare crude hydrogen fluoride gas; the mixing device is connected to each liquid outlet and sulfuric acid inlet of the main reaction device, and is used to mix sulfuric acid from different sections and then return it to the main reaction device to realize sulfuric acid circulation treatment of hydrogen fluoride gas.

The invention provides a method for producing hydrogen fluoride, comprising the following steps: A) hydrofluorosilicic acid and concentrated sulfuric acid react in a main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride; B) the silicon tetrafluoride gas is introduced into a silicon tetrafluoride generation zone; the sulfuric acid solution containing hydrogen fluoride is split to form at least two paths for preparing hydrogen fluoride gas; wherein: the first part of the sulfuric acid solution containing hydrogen fluoride is introduced into a distillation zone for separation, the separated hydrogen fluoride gas is introduced into a hydrogen fluoride generation zone to remove moisture, and dry crude hydrogen fluoride gas is collected; the second part of the sulfuric acid solution containing hydrogen fluoride and initial concentrated sulfuric acid are introduced into a mixing zone, and the diluted sulfuric acid solution after mixing is recycled to the main reaction zone.

The present invention directly conducts sulfuric acid circulation treatment in parallel in the separation section, uses sulfuric acid to treat the gas in each section, recovers silicon tetrafluoride gas produced in the reaction section, light component gas produced in the purification section and hydrogen fluoride in the stripping section, thereby reducing HF emissions in the tail gas, improving HF yield and purity, and innovating a new path for fluorine recovery in the system. In addition, the hydrogen fluoride production method provided by the present invention can reduce energy consumption while reducing fluorine loss.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a method for producing hydrogen fluoride according to the present invention;

FIG2 is a schematic diagram of a method for producing hydrogen fluoride provided in a first embodiment of the present invention;

FIG3 is a schematic diagram of a method for producing hydrogen fluoride provided in a second embodiment of the present invention;

FIG4 is a schematic diagram of a method for producing hydrogen fluoride provided in a third embodiment of the present invention;

FIG5 is a schematic diagram of a method for producing hydrogen fluoride provided in a fourth embodiment of the present invention.

DETAILED DESCRIPTION

The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

As shown in FIG1 , the present invention provides a method for producing hydrogen fluoride, comprising the following steps:

A) fluorosilicic acid and the first concentrated sulfuric acid react in a main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride;

B) the silicon tetrafluoride gas is passed into the silicon tetrafluoride generation zone;

The sulfuric acid solution containing hydrogen fluoride is split into at least two paths for preparing hydrogen fluoride gas; wherein:

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into the distillation zone for separation, passing the separated hydrogen fluoride gas into the hydrogen fluoride generation zone to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The second part of the sulfuric acid solution containing hydrogen fluoride is heated and introduced into the mixing zone with the second concentrated sulfuric acid, and the diluted sulfuric acid solution after the mixing treatment is recycled into the main reaction zone as a raw material.

In step A):

Fluorosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride.

In certain embodiments of the present invention, the mass concentration of fluorosilicic acid used in the main reaction zone is 30% to 55%, the mass concentration of the first concentrated sulfuric acid is 68% to 95%, and the mass concentration of sulfuric acid in the product solution obtained by reaction dilution is about 65% to 80%.

In certain embodiments of the present invention, the source of the fluorosilicic acid includes phosphate rock or fluorite, which can be prepared by _SiF4 absorption through water, or prepared by silica sand and hydrofluoric acid, or prepared by mixing and heating silica sand, calcium fluoride and concentrated sulfuric acid.

In certain embodiments of the present invention, the second portion of the sulfuric acid solution containing hydrogen fluoride can recover heat through a pipeline, and further circulate the heat to the main reaction zone.

The present invention has no special restrictions on the reaction parameters of the fluorosilicic acid and the first concentrated sulfuric acid in the main reaction zone, and the reaction parameters well known to those skilled in the art can be used; preferably, the reaction temperature of the fluorosilicic acid and the first concentrated sulfuric acid is 80-130° C. After the reaction, the generated gas containing silicon tetrafluoride contains a small amount of hydrogen fluoride gas, which is released from the solution, and most of the hydrogen fluoride remains in the sulfuric acid solution.

In step B):

The silicon tetrafluoride gas is introduced into the silicon tetrafluoride generation zone;

The sulfuric acid solution containing hydrogen fluoride is split into at least two paths for preparing hydrogen fluoride gas; wherein:

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into the distillation zone for separation, passing the separated hydrogen fluoride gas into the hydrogen fluoride generation zone to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The second part of the sulfuric acid solution containing hydrogen fluoride is heated and introduced into the mixing zone with the second concentrated sulfuric acid, and the diluted sulfuric acid solution after the mixing treatment is recycled into the main reaction zone as a raw material.

In certain embodiments of the present invention, the gas containing silicon tetrafluoride obtained in step A) contains impurities such as H ₂ O, HF, and H ₂ SO ₄ vapor.

In certain embodiments of the present invention, the volume ratio of the first part of the sulfuric acid solution containing hydrogen fluoride to the second part of the sulfuric acid solution containing hydrogen fluoride is 0.25-4:1.

In certain embodiments of the present invention, in the hydrogen fluoride generation zone, the treatment temperature is 70-100° C.; and the mass concentration of sulfuric acid is 70%-85%.

In certain embodiments of the present invention, the temperature of the silicon tetrafluoride production zone is 20-120° C., preferably 60-120° C.; the mass concentration of the second concentrated sulfuric acid introduced into the silicon tetrafluoride production zone is 80%-95%.

Specifically, the function of the mixing zone shown in Figure 1 is to achieve impurity removal, recovery and drying by circulating the material through different sulfuric acid cycles to improve the yield and purity of hydrogen fluoride gas. Specifically, no less than two sulfuric acid towers can be used in the mixing zone to treat the target gas.

Two-tower solution:

In certain embodiments of the present invention, as shown in FIG2 , the mixing zone includes a silicon tetrafluoride production zone, and the silicon tetrafluoride production zone is provided with a concentrated sulfuric acid inlet for adding a second concentrated sulfuric acid; the process route adds a sulfuric acid treatment line compared to conventional industry technology, namely: 1) main reaction zone → silicon tetrafluoride production zone (tower 2) → main reaction zone;

Fluorosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride; after the reaction, on the basis of conventional distillation separation of the fluorine-containing sulfuric acid solution (the first part of the sulfuric acid solution containing hydrogen fluoride, referred to as fluorine-containing sulfuric acid for separation), another fluorine-containing sulfuric acid solution for circulation (the second part of the sulfuric acid solution containing hydrogen fluoride, referred to as fluorine-containing sulfuric acid for circulation) is diverted and introduced into the silicon tetrafluoride production zone; and the second concentrated sulfuric acid also flows through the silicon tetrafluoride production zone to dry the silicon tetrafluoride gas drawn out through the main reaction zone; the second concentrated sulfuric acid flows through the silicon tetrafluoride production zone and is mixed with the fluorine-containing sulfuric acid for circulation in the silicon tetrafluoride production zone, and is reused in the main reaction zone as a raw material.

Furthermore, the circulating fluorinated sulfuric acid can absorb excess heat during the circulation process, and this heat can be recovered for use in the main reaction zone to increase the temperature of the reaction zone, thereby reducing the amount of steam required for the separation fluorinated sulfuric acid, and significantly reducing energy consumption.

In certain embodiments of the present invention, after the separation in the distillation zone, the process further comprises:

Stripping the distillation mother liquid separated in the distillation zone to obtain high-temperature hydrogen fluoride gas and conveying it to the silicon tetrafluoride production zone;

The initial concentrated sulfuric acid enters the silicon tetrafluoride generation zone to dry the silicon tetrafluoride gas drawn from the main reaction zone and the high-temperature hydrogen fluoride gas obtained by stripping; the second concentrated sulfuric acid enters the silicon tetrafluoride generation zone and is mixed with the circulating fluorine-containing sulfuric acid and then reused in the main reaction zone. This process absorbs heat during the sulfuric acid circulation process, increases the temperature of the reaction zone, reduces the amount of steam required for separation of fluorine-containing sulfuric acid, and can significantly reduce energy consumption. The separated hydrogen fluoride gas is passed into the hydrogen fluoride generation zone to remove moisture, and the sulfuric acid solution in the hydrogen fluoride generation zone is also reused in the main reaction zone to reduce material loss.

In certain embodiments of the present invention, after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas generated in the distillation process is transported to the hydrogen fluoride generation zone, and the hydrogen fluoride gas in the production system can be further recovered to improve the product yield.

In certain embodiments of the present invention, the condensation is performed in a condensation tower. The crude hydrogen fluoride gas has a low moisture content, but may contain sulfuric acid, so condensation can remove the high-boiling sulfuric acid. The sulfuric acid solution obtained by the condensation is recycled to the hydrogen fluoride generation zone.

Three-tower plan:

In certain embodiments of the present invention, the mixing zone includes a silicon tetrafluoride production zone and a hydrogen fluoride recovery zone, respectively; as shown in FIG3 , the process route adds two sulfuric acid treatment lines compared to conventional industry technologies, namely: 1) main reaction zone → hydrogen fluoride recovery zone → main reaction zone; 2) initial concentrated sulfuric acid → silicon tetrafluoride production zone → hydrogen fluoride recovery zone → main reaction zone.

Fluorosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride; as mentioned above, after the reaction, the flow is split to form two fluorine-containing sulfuric acid. The difference from the above two-tower scheme is that the circulating fluorine-containing sulfuric acid is introduced into the hydrogen fluoride recovery zone; and the second concentrated sulfuric acid flows through the silicon tetrafluoride generation zone. The silicon tetrafluoride gas generated in this zone contains impurities such as _H2O , HF, _{and H2SO4} vapor. The above impurities enter the sulfuric acid solution. In the hydrogen fluoride absorption zone, the circulating fluorine-containing sulfuric acid is mixed with the sulfuric acid solution flowing through the silicon tetrafluoride generation zone and is reused in the main reaction zone as a raw material.

In certain embodiments of the present invention, after the separation in the distillation zone, the process further comprises:

The distillation mother liquor separated in the distillation zone is stripped to obtain high-temperature hydrogen fluoride gas and transported to the hydrogen fluoride recovery zone; the second concentrated sulfuric acid enters the silicon tetrafluoride generation zone and the hydrogen fluoride recovery zone in sequence, the mass concentration of sulfuric acid in the hydrogen fluoride recovery zone is 68%-85%, the treatment temperature is 100-200°C, preferably 120-160°C, and is used to dry the silicon tetrafluoride gas drawn out from the main reaction zone and the high-temperature hydrogen fluoride gas obtained by stripping; the second concentrated sulfuric acid enters the silicon tetrafluoride generation zone and is mixed with the circulating fluorine-containing sulfuric acid in the hydrogen fluoride recovery zone and then reused in the main reaction zone, the process absorbs heat during the sulfuric acid circulation process, increases the temperature of the reaction zone, reduces the amount of steam required for the separation fluorine-containing sulfuric acid, and can significantly reduce energy consumption.

The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the silicon tetrafluoride production zone for drying.

In certain embodiments of the present invention, after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas generated in the distillation process is transported to the hydrogen fluoride recovery zone, and the hydrogen fluoride gas in the production system can be further recovered to improve the product yield.

In certain embodiments of the present invention, the condensation is performed in a condensation tower. The crude hydrogen fluoride gas has a low moisture content, but may contain sulfuric acid, so condensation can remove the high-boiling sulfuric acid. The sulfuric acid solution obtained by the condensation is recycled to the hydrogen fluoride generation zone.

In the three-tower scheme, the hydrogen fluoride gas returned to the hydrogen fluoride recovery zone from various routes, such as the high-temperature hydrogen fluoride gas obtained by stripping and the light component gas recovered by distillation, can be further dried through the above-mentioned circulation pipeline, and the soluble impurities contained in the gas can be removed.

Four-tower plan (I):

In certain embodiments of the present invention, as shown in FIG. 4 , the mixing zone includes a silicon tetrafluoride generation zone, a hydrogen fluoride recovery zone and a hydrogen fluoride absorption zone, respectively; concentrated sulfuric acid inlets are respectively provided on the silicon tetrafluoride generation zone and the hydrogen fluoride absorption zone for adding a second concentrated sulfuric acid, and the second concentrated sulfuric acid simultaneously flows through the silicon tetrafluoride generation zone and the hydrogen fluoride absorption zone to form two parallel flow paths; compared with conventional industry technologies, this process route adds three sulfuric acid treatment lines, namely: 1) main reaction zone→hydrogen fluoride recovery zone→main reaction zone; 2) initial concentrated sulfuric acid→silicon tetrafluoride generation zone→hydrogen fluoride recovery zone→main reaction zone; 3) initial concentrated sulfuric acid→hydrogen fluoride absorption zone→hydrogen fluoride generation zone→main reaction zone.

Fluorosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride; different from the aforementioned three-tower scheme, the second sulfuric acid is added in parallel to a circulating sulfuric acid pipeline to further absorb free hydrogen fluoride gas in the system. Based on this embodiment, those skilled in the art can also add more parallel pipelines to increase circulation, and similar modifications are included in the concept of the present invention.

In certain embodiments of the present invention, after the separation in the distillation zone, the process further comprises:

Stripping the distillation mother liquid separated in the distillation zone to obtain high-temperature hydrogen fluoride gas and conveying it to the hydrogen fluoride recovery zone;

The initial concentrated sulfuric acid is divided into two paths and enters the hydrogen fluoride absorption zone and the silicon tetrafluoride generation zone, respectively used for drying or absorbing the gas therein; the sulfuric acid solution flowing through the hydrogen fluoride absorption zone flows to the hydrogen fluoride generation zone and then is recycled to the main reaction zone, the sulfuric acid concentration in the hydrogen fluoride absorption zone is 68% to 85%, and the treatment temperature is 10 to 140° C., preferably 20 to 100° C.; the sulfuric acid solution flowing through the silicon tetrafluoride generation zone flows to the hydrogen fluoride recovery zone and then is mixed with the circulating fluorine-containing sulfuric acid and recycled to the main reaction zone.

The hydrogen fluoride gas flowing through the hydrogen fluoride recovery zone is transported to the hydrogen fluoride absorption zone to be absorbed by sulfuric acid and to remove impurities.

In certain embodiments of the present invention, after obtaining the crude hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas generated in the distillation process is transported to the hydrogen fluoride recovery zone, and the hydrogen fluoride gas in the production system can be further recovered to improve the product yield.

In certain embodiments of the present invention, the condensation is performed in a condensation tower. The crude hydrogen fluoride gas has a low moisture content, but may contain sulfuric acid, so condensation can remove the high-boiling sulfuric acid. The sulfuric acid solution obtained by the condensation is recycled to the hydrogen fluoride generation zone.

In the four-tower scheme (I), the second concentrated sulfuric acid enters the silicon tetrafluoride generation zone to dry the silicon tetrafluoride gas drawn out through the main reaction zone; the second concentrated sulfuric acid enters the hydrogen fluoride absorption zone to dry the high-temperature hydrogen fluoride gas obtained by stripping and the light component gas recovered by distillation.

Four-tower plan (II):

In certain embodiments of the present invention, as shown in FIG. 5 , the mixing zone comprises a silicon tetrafluoride production zone and a hydrogen fluoride recovery zone, each of which is independent; the silicon tetrafluoride production zone is provided with a concentrated sulfuric acid inlet for adding a second concentrated sulfuric acid; the second concentrated sulfuric acid flows through the silicon tetrafluoride production zone and the hydrogen fluoride recovery zone in sequence, and is mixed with the second portion of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery zone, and is used to dry and/or absorb one or more gases in the silicon tetrafluoride production zone and the hydrogen fluoride recovery zone; the crude hydrogen fluoride gas is mixed with the sulfuric acid solution in the pre-purification zone, and pre-purified to obtain pre-purified hydrogen fluoride gas.

The hydrogen fluoride gas drawn out from the hydrogen fluoride generation zone is passed into the pre-purification zone to remove high boiling point impurities (mainly sulfuric acid).

Compared with conventional industry technologies, this process route adds three sulfuric acid treatment lines, namely: 1) main reaction zone → hydrogen fluoride recovery zone → main reaction zone; 2) second concentrated sulfuric acid → silicon tetrafluoride production zone → hydrogen fluoride recovery zone → main reaction zone; 3) hydrogen fluoride production zone → pre-purification tower → main reaction zone.

Fluorosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and a sulfuric acid solution containing hydrogen fluoride; as described above, after the reaction, the two flows are split to form fluorine-containing sulfuric acid. Unlike the aforementioned three-tower scheme, the treated sulfuric acid solution is reused in the main reaction zone as a raw material. The hydrogen fluoride gas drawn out from the hydrogen fluoride generation zone is passed into the pre-purification zone to remove high and low boiling point impurities, and sulfuric acid is further recovered to enter the main reaction zone, and the light component gas separated from the upper part of the pre-purification tower is circulated into the system for reabsorption. Based on this embodiment, those skilled in the art can also add a circulation recovery pipeline, and similar modifications are covered within the concept of the present invention.

The top of the pre-purification zone is controlled by two stages of temperature to ensure the removal of high and low boiling point impurities.

The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the silicon tetrafluoride production zone for drying.

In certain embodiments of the present invention, after obtaining the pre-purified hydrogen fluoride gas, the process further comprises:

Condensing and rectifying the pre-purified hydrogen fluoride gas to obtain purified hydrogen fluoride gas;

The light component gas generated in the pre-purification and distillation process is transported to the hydrogen fluoride recovery zone, and the hydrogen fluoride gas in the production system can be further recovered to improve the product yield.

In certain embodiments of the present invention, the condensation is performed in a condensation tower. The crude hydrogen fluoride gas has a low moisture content, but may contain sulfuric acid, so condensation can remove the high-boiling sulfuric acid. The sulfuric acid solution obtained by the condensation is recycled to the hydrogen fluoride generation zone.

In the four-tower scheme (II), the second concentrated sulfuric acid enters the silicon tetrafluoride generation zone and is used to dry the silicon tetrafluoride gas drawn out from the main reaction zone and the light component gas recovered by distillation.

In certain embodiments of the present invention, in the hydrogen fluoride recovery zone, the treatment temperature is 100-200° C., preferably 120-160° C.; and the mass concentration of sulfuric acid is 68%-85%.

In certain embodiments of the present invention, in the pre-purification zone, the temperature of the HF gas is 10-80° C., specifically 70-80° C.; the temperature of the recovered sulfuric acid is 60-100° C.; and the mass concentration of the recovered sulfuric acid is greater than 90%.

The present invention also provides a hydrogen fluoride production system for implementing the above-mentioned production method, comprising:

A main reaction device, used for adding fluorosilicic acid and the first concentrated sulfuric acid for mixed reaction, and discharging gaseous products and liquid products; the main reaction device is provided with at least two liquid outlets;

A distillation device, used for separating hydrogen fluoride gas from part of the fluorine-containing sulfuric acid discharged from the main reaction device; the distillation device is connected to one of the liquid outlets of the main reaction device;

The mixing device includes a hydrogen fluoride generating device to prepare crude hydrogen fluoride gas; the mixing device is connected to each liquid outlet and sulfuric acid inlet of the main reaction device, and is used to mix sulfuric acid from different sections and then return it to the main reaction device to realize sulfuric acid circulation treatment of hydrogen fluoride gas.

Specifically, they include:

The main reaction device is provided with a silicon tetrafluoride gas outlet, a first fluorine-containing sulfuric acid outlet, a second fluorine-containing sulfuric acid outlet and a sulfuric acid inlet;

A distillation device; the distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction device;

A mixing device; the mixing device is provided with a concentrated sulfuric acid inlet and a fluorine-containing sulfuric acid inlet, the fluorine-containing sulfuric acid inlet of the mixing device is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device; the sulfuric acid outlet of the mixing device is connected to the sulfuric acid inlet of the main reaction device.

A hydrogen fluoride generating device; the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, and the hydrogen fluoride gas inlet is connected to the gas outlet of the distillation device.

The hydrogen fluoride production system provided by the present invention comprises a main reaction device. The main reaction device is provided with a silicon tetrafluoride gas outlet, a first fluorine-containing sulfuric acid outlet, a second fluorine-containing sulfuric acid outlet and a sulfuric acid inlet. In certain embodiments of the present invention, the main reaction device is a main reactor. The present invention does not have any special restrictions on the type and size of the main reaction device, and a reaction container familiar to those skilled in the art can be used.

The hydrogen fluoride production system provided by the present invention further comprises a distillation device. The distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction zone. In certain embodiments of the present invention, the distillation device is a distiller. The present invention has no particular restrictions on the structure and type of the distillation device, and it can be a generally commercially available distiller.

The hydrogen fluoride production system provided by the present invention also includes a mixing device. The mixing device is provided with a concentrated sulfuric acid inlet and a fluorine-containing sulfuric acid inlet, the fluorine-containing sulfuric acid inlet of the mixing device is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device; the sulfuric acid outlet of the mixing device is connected to the recycled sulfuric acid inlet of the main reaction device.

The hydrogen fluoride production system provided by the present invention also includes a hydrogen fluoride generating device; the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, and the hydrogen fluoride gas inlet of the hydrogen fluoride generating device is connected to the gas outlet of the distillation device.

In certain embodiments of the present invention, the hydrogen fluoride generating device is a first sulfuric acid tower. The first sulfuric acid tower may be a commonly commercially available sulfuric acid tower.

The first option:

In certain embodiments of the present invention, the mixing device includes a silicon tetrafluoride generating device;

The gas inlet of the silicon tetrafluoride generating device is connected to the gas outlet of the main reaction device;

The silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet and a fluorine-containing sulfuric acid inlet, and the fluorine-containing sulfuric acid inlet of the silicon tetrafluoride generating device is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device.

The sulfuric acid solution outlet of the hydrogen fluoride generating device is connected to the first circulating sulfuric acid inlet of the main reaction device.

The sulfuric acid solution outlet of the silicon tetrafluoride generating device is connected to the second circulating sulfuric acid inlet of the main reaction device.

In certain embodiments of the present invention, the silicon tetrafluoride generating device is a second sulfuric acid tower, which can be a commercially available sulfuric acid tower.

In certain embodiments of the present invention, the production system further comprises a stripping device;

The inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device;

The outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the silicon tetrafluoride generating device.

In certain embodiments of the present invention, the stripping device is a stripping tower, which can be a commercially available stripping tower.

In certain embodiments of the present invention, the production system further comprises: a condensation tower and a distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride generating device.

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas.

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to a second light component gas inlet of the hydrogen fluoride generating device.

In certain embodiments of the present invention, the condensation tower is a generally commercially available condensation tower; and the distillation tower is a generally commercially available distillation tower.

Second option:

In certain embodiments of the present invention, the mixing zone comprises: a silicon tetrafluoride generating device and a hydrogen fluoride recovery device which are independently arranged;

The gas inlet of the silicon tetrafluoride generating device is connected to the gas outlet of the main reaction device;

The silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet;

The hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, which is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device. The hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, which is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device.

In certain embodiments of the present invention, the silicon tetrafluoride generating device is a second sulfuric acid tower, which can be a commercially available sulfuric acid tower.

In certain embodiments of the present invention, the hydrogen fluoride recovery device is a third sulfuric acid tower. The third sulfuric acid tower can be a commonly available sulfuric acid tower.

In certain embodiments of the present invention, the production system further comprises a stripping device;

The inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device;

The outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride recovery device.

In certain embodiments of the present invention, the stripping device is a stripping tower, which can be a commercially available stripping tower.

In certain embodiments of the present invention, the production system further comprises: a condensation tower and a distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device.

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas;

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the second light component gas inlet of the hydrogen fluoride recovery device.

In certain embodiments of the present invention, the condensation tower is a generally commercially available condensation tower; and the distillation tower is a generally commercially available distillation tower.

The hydrogen fluoride gas outlet of the hydrogen fluoride recovery device is connected to the hydrogen fluoride gas inlet of the silicon tetrafluoride production device.

The third option:

In certain embodiments of the present invention, the mixing zone comprises: a silicon tetrafluoride generating device, a hydrogen fluoride recovering device and a hydrogen fluoride absorbing device which are independently arranged;

The gas inlet of the silicon tetrafluoride generating device is connected to the gas outlet of the main reaction device;

The silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet; the hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, the fluorine-containing sulfuric acid inlet of the hydrogen fluoride recovery device is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device, and the hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, and the sulfuric acid inlet is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device;

The hydrogen fluoride absorption device is provided with a concentrated sulfuric acid inlet and a sulfuric acid outlet; the sulfuric acid outlet of the hydrogen fluoride absorption device is connected to the sulfuric acid inlet of the hydrogen fluoride generation device.

In certain embodiments of the present invention, the silicon tetrafluoride generating device is a second sulfuric acid tower, which can be a commercially available sulfuric acid tower.

In certain embodiments of the present invention, the hydrogen fluoride recovery device is a third sulfuric acid tower. The third sulfuric acid tower can be a commonly available sulfuric acid tower.

In certain embodiments of the present invention, the hydrogen fluoride absorption device is a fourth sulfuric acid tower. The fourth sulfuric acid tower can be a commonly available sulfuric acid tower.

In certain embodiments of the present invention, the production system further comprises a stripping device;

The inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device;

The outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride recovery device.

In certain embodiments of the present invention, the stripping device is a stripping tower, which can be a commercially available stripping tower.

In certain embodiments of the present invention, the production system further comprises: a condensation tower and a distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device.

The gas inlet of the distillation tower is connected to the gas outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas;

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the light component gas inlet of the hydrogen fluoride recovery device.

The hydrogen fluoride gas outlet of the hydrogen fluoride recovery device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride absorption device.

In certain embodiments of the present invention, the condensation tower is a generally commercially available condensation tower; and the distillation tower is a generally commercially available distillation tower.

The fourth option:

In certain embodiments of the present invention, the mixing zone comprises: a silicon tetrafluoride generating device and a hydrogen fluoride recovery device which are independently arranged;

The gas inlet of the silicon tetrafluoride generating device is connected to the gas outlet of the main reaction device;

The silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet;

The hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, which is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device. The hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, which is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device.

In certain embodiments of the present invention, the silicon tetrafluoride generating device is a second sulfuric acid tower, which can be a commercially available sulfuric acid tower.

In certain embodiments of the present invention, the hydrogen fluoride recovery device is a third sulfuric acid tower. The third sulfuric acid tower can be a commonly available sulfuric acid tower.

In certain embodiments of the present invention, the production system further comprises: a pre-purification device; the gas inlet of the pre-purification device is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the high boiling point impurity outlet of the pre-purification device is connected to the high boiling point impurity inlet of the hydrogen fluoride generating device. In certain embodiments of the present invention, the pre-purification device is a fifth sulfuric acid tower. The fifth sulfuric acid tower can be a generally commercially available sulfuric acid tower.

In certain embodiments of the present invention, the production system further comprises: a condensation tower and a distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the pre-purification device; the liquid outlet of the condensation tower is connected to the liquid inlet of the pre-purification device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device.

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas;

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the second light component gas inlet of the hydrogen fluoride recovery device.

The hydrogen fluoride gas outlet of the hydrogen fluoride recovery device is connected to the hydrogen fluoride gas inlet of the silicon tetrafluoride production device.

In certain embodiments of the present invention, the condensation tower is a generally commercially available condensation tower; the distillation tower is a generally commercially available distillation tower.

The present invention has no particular limitation on the sources of the raw materials used above, and they can be generally commercially available.

In order to further illustrate the present invention, a method for producing hydrogen fluoride provided by the present invention is described in detail below in conjunction with examples, but it should not be construed as limiting the scope of protection of the present invention.

Example 1

The hydrogen fluoride production system shown in FIG2 comprises:

Main reaction unit (main reactor);

A distillation device (distiller); the distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction device;

A hydrogen fluoride generating device (first sulfuric acid tower); the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, the hydrogen fluoride gas inlet of the hydrogen fluoride generating device is connected to the gas outlet of the distillation device; the sulfuric acid solution outlet of the hydrogen fluoride generating device is connected to the first circulating sulfuric acid inlet of the main reaction device; the sulfuric acid solution outlet of the silicon tetrafluoride generating device is connected to the second circulating sulfuric acid inlet of the main reaction device;

A silicon tetrafluoride generating device (a second sulfuric acid tower); a gas inlet of the silicon tetrafluoride generating device is connected to a gas outlet of the main reaction device; the silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet (for adding a second concentrated sulfuric acid) and a fluorine-containing sulfuric acid inlet, and the fluorine-containing sulfuric acid inlet of the silicon tetrafluoride generating device is connected to a second fluorine-containing sulfuric acid outlet of the main reaction device;

A stripping device (stripping tower); the inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device; the outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the silicon tetrafluoride generating device;

Condensation tower and distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride generating device.

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas.

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to a second light component gas inlet of the hydrogen fluoride generating device.

The method for producing hydrogen fluoride comprises:

1) concentrated hydrofluorosilicic acid (mass concentration of 48%) and first concentrated sulfuric acid (mass concentration of 80%) react in a main reactor to generate a gas containing silicon tetrafluoride and a sulfuric acid solution containing hydrogen fluoride; the temperature of the product solution after the reaction is 110° C., and the mass concentration of sulfuric acid in the product solution is 65%;

2) the silicon tetrafluoride gas is introduced into a silicon tetrafluoride generating device;

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into a distillation device for separation, passing the separated hydrogen fluoride gas into a hydrogen fluoride generation device at a treatment temperature of 70° C. and a mass concentration of sulfuric acid of 85% to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The crude hydrogen fluoride gas is condensed in a condensation tower and rectified in a distillation tower to obtain purified hydrogen fluoride gas and light component gas; the light component gas generated in the distillation process is transported to a hydrogen fluoride generation device. The sulfuric acid solution obtained by the condensation is reused in the hydrogen fluoride generation device;

The second concentrated sulfuric acid flows through the silicon tetrafluoride generating device (the treatment temperature is 70° C., and the mass concentration of sulfuric acid is 95%), and is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the silicon tetrafluoride generating device; the diluted sulfuric acid solution after treatment in the silicon tetrafluoride generating device is returned to the main reaction device;

The volume ratio of the first part of the sulfuric acid solution containing hydrogen fluoride to the second part of the sulfuric acid solution containing hydrogen fluoride is 2:1;

The mother liquid separated by the distiller is stripped to obtain high-temperature hydrogen fluoride gas, which is transported to the silicon tetrafluoride generating device, mixed with the second part of the sulfuric acid solution containing hydrogen fluoride, and then recycled to the main reaction device.

After calculation and testing, the yield of purified hydrogen fluoride obtained by the distillation tower is 97.9% and the purity is 99.99%. Specifically, the yield is calculated by the ratio of the actually collected hydrogen fluoride to the theoretical value calculated by the reaction materials.

Example 2

The hydrogen fluoride production system shown in FIG3 comprises:

Main reaction unit (main reactor);

A distillation device (distiller); the distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction device;

A hydrogen fluoride generating device (first sulfuric acid tower); the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, and the hydrogen fluoride gas inlet of the hydrogen fluoride generating device is connected to the gas outlet of the distillation device;

A silicon tetrafluoride generating device (a second sulfuric acid tower); a gas inlet of the silicon tetrafluoride generating device is connected to a gas outlet of the main reactor; the silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet for adding a second concentrated sulfuric acid;

A hydrogen fluoride recovery device (third sulfuric acid tower); the hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, which is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device, and the hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, which is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device;

A stripping device (stripping tower); the inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device; the outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride recovery device;

Condensation tower and distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device;

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas;

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the second light component gas inlet of the hydrogen fluoride recovery device.

The method for producing hydrogen fluoride comprises:

1) concentrated hydrofluorosilicic acid (mass concentration of 48%) and first concentrated sulfuric acid (mass concentration of 85%) react in a main reactor to generate a gas containing silicon tetrafluoride and a sulfuric acid solution containing hydrogen fluoride; the temperature of the product solution after the reaction is 110° C., and the mass concentration of sulfuric acid in the product solution is 70%;

2) the silicon tetrafluoride gas is introduced into a silicon tetrafluoride generating device;

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into a distillation device for separation, passing the separated hydrogen fluoride gas into a hydrogen fluoride generation device (the treatment temperature is 90° C., and the mass concentration of sulfuric acid is 80%) to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The crude hydrogen fluoride gas is condensed in a condensation tower and rectified in a distillation tower to obtain purified hydrogen fluoride gas and light component gas; the light component gas generated in the distillation process is transported to a hydrogen fluoride recovery device; the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device; the hydrogen fluoride gas in the hydrogen fluoride recovery device is transported to a silicon tetrafluoride generation device for drying; the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device;

The second concentrated sulfuric acid flows through the silicon tetrafluoride generation zone (the treatment temperature is 90° C., the mass concentration of sulfuric acid is 90%) and the hydrogen fluoride recovery device (the treatment temperature is 135° C., the mass concentration of sulfuric acid is 75%) in sequence, and is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery device to dry and/or absorb one or more gases in the silicon tetrafluoride generation device and the hydrogen fluoride recovery device;

The volume ratio of the first part of the sulfuric acid solution containing hydrogen fluoride to the second part of the sulfuric acid solution containing hydrogen fluoride is 2:1;

The mother liquor separated by the distillation device is stripped to obtain high-temperature hydrogen fluoride gas, which is transported to a hydrogen fluoride recovery device, mixed with the second part of the sulfuric acid solution containing hydrogen fluoride, and then recycled to the main reaction device.

After calculation and detection, the yield of purified hydrogen fluoride obtained by the distillation tower is 99.2%, the purity is 99.99%, the impurity gas is basically silicon tetrafluoride gas, the volume content of water in the impurity gas is less than 3%, and the volume content of air is less than 1%.

Example 3

The hydrogen fluoride production system shown in FIG4 comprises:

Main reaction unit (main reactor);

A distillation device (distiller); the distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction device;

A hydrogen fluoride generating device (first sulfuric acid tower); the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, and the hydrogen fluoride gas inlet of the hydrogen fluoride generating device is connected to the gas outlet of the distillation device;

A silicon tetrafluoride generating device (a second sulfuric acid tower); a gas inlet of the silicon tetrafluoride generating device is connected to a gas outlet of the main reactor; the silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet for adding a second concentrated sulfuric acid;

A hydrogen fluoride recovery device (third sulfuric acid tower); the hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, which is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device, and the hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, which is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device;

The hydrogen fluoride absorption device (the fourth sulfuric acid tower) is provided with a concentrated sulfuric acid inlet for adding initial concentrated sulfuric acid; the sulfuric acid outlet of the hydrogen fluoride absorption device is connected to the sulfuric acid inlet of the hydrogen fluoride generation device;

A stripping device; the inlet of the stripping device is connected to the outlet of the distillation mother liquid of the distillation device; the outlet of the stripping device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride recovery device;

Condensation tower and distillation tower;

The gas inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the liquid outlet of the condensation tower is connected to the liquid inlet of the hydrogen fluoride generating device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device;

The gas inlet of the distillation tower is connected to the gas outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas; the distillation tower also includes a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the light component gas inlet of the hydrogen fluoride recovery device.

The hydrogen fluoride gas outlet of the hydrogen fluoride recovery device is connected to the hydrogen fluoride gas inlet of the hydrogen fluoride absorption device.

The method for producing hydrogen fluoride comprises:

1) concentrated hydrofluorosilicic acid (mass concentration of 45%) and first concentrated sulfuric acid (mass concentration of 80%) react in a main reactor to generate a gas containing silicon tetrafluoride and a sulfuric acid solution containing hydrogen fluoride; the temperature of the product solution after the reaction is 110° C., and the mass concentration of sulfuric acid in the product solution is 75%;

2) the silicon tetrafluoride gas is introduced into a silicon tetrafluoride generating device;

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into a distillation device for separation, passing the separated hydrogen fluoride gas into a hydrogen fluoride generation device (the treatment temperature is 70° C., and the mass concentration of sulfuric acid is 85%) to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The crude hydrogen fluoride gas is condensed in a condensing tower and rectified in a distillation tower to obtain purified hydrogen fluoride gas and light component gas; the light component gas generated in the distillation process is transported to a hydrogen fluoride recovery device (the treatment temperature is 120° C., and the mass concentration of sulfuric acid is 70%); the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device; the hydrogen fluoride gas in the hydrogen fluoride recovery device is transported to a hydrogen fluoride absorption device for drying; the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device;

The second concentrated sulfuric acid flows through the silicon tetrafluoride generating device (the treatment temperature is 120° C., and the mass concentration of sulfuric acid is 95%) and the hydrogen fluoride absorbing device (the treatment temperature is 60° C., and the mass concentration of sulfuric acid is 85%) to form two parallel flow paths;

The sulfuric acid solution flowing out of the silicon tetrafluoride generating device is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery device to dry and/or absorb one or more gases in the silicon tetrafluoride generating device and the hydrogen fluoride recovery device;

The sulfuric acid solution flowing out of the hydrogen fluoride absorption device is mixed with the sulfuric acid solution in the hydrogen fluoride generation device to dry and/or absorb one or more gases in the hydrogen fluoride absorption device and the hydrogen fluoride generation device;

The volume ratio of the first part of the sulfuric acid solution containing hydrogen fluoride to the second part of the sulfuric acid solution containing hydrogen fluoride is 2:1;

The mother liquor separated by the distillation device is stripped to obtain high-temperature hydrogen fluoride gas, which is transported to a hydrogen fluoride recovery device, mixed with the second part of the sulfuric acid solution containing hydrogen fluoride, and then recycled to the main reaction device.

Through calculation and detection, the yield of purified hydrogen fluoride obtained by the distillation tower is 98.3% and the purity is 99.99%.

Example 4

The hydrogen fluoride production system shown in FIG5 comprises:

Main reaction unit (main reactor);

A distillation device (distiller); the distillation device is connected to the first fluorine-containing sulfuric acid outlet of the main reaction device;

A hydrogen fluoride generating device (first sulfuric acid tower); the hydrogen fluoride generating device is provided with a hydrogen fluoride gas inlet, and the hydrogen fluoride gas inlet of the hydrogen fluoride generating device is connected to the gas outlet of the distillation device;

A silicon tetrafluoride generating device (a second sulfuric acid tower); a gas inlet of the silicon tetrafluoride generating device is connected to a gas outlet of the main reaction device; the silicon tetrafluoride generating device is provided with a concentrated sulfuric acid inlet for adding a second concentrated sulfuric acid;

A hydrogen fluoride recovery device (third sulfuric acid tower); the hydrogen fluoride recovery device is provided with a fluorine-containing sulfuric acid inlet, which is connected to the second fluorine-containing sulfuric acid outlet of the main reaction device, and the hydrogen fluoride recovery device is also provided with a sulfuric acid inlet, which is connected to the sulfuric acid outlet of the silicon tetrafluoride generating device;

A pre-purification device (fifth sulfuric acid tower); the gas inlet of the pre-purification device is connected to the hydrogen fluoride gas outlet of the hydrogen fluoride generating device; the high boiling point impurity outlet of the pre-purification device is connected to the high boiling point impurity inlet of the hydrogen fluoride generating device;

Condensation tower and distillation tower;

The inlet of the condensation tower is connected to the hydrogen fluoride gas outlet of the pre-purification device; the liquid outlet of the condensation tower is connected to the liquid inlet of the pre-purification device;

The condensation tower further comprises a light component gas outlet, and the light component gas outlet of the condensation tower is connected to the first light component gas inlet of the hydrogen fluoride recovery device;

The liquid inlet of the distillation tower is connected to the liquid outlet of the condensation tower; the hydrogen fluoride gas outlet of the distillation tower obtains purified hydrogen fluoride gas;

The distillation tower further comprises a light component gas outlet, and the light component gas outlet of the distillation tower is connected to the second light component gas inlet of the hydrogen fluoride recovery device;

The hydrogen fluoride gas outlet of the hydrogen fluoride recovery device is connected to the hydrogen fluoride gas inlet of the silicon tetrafluoride production device.

The method for producing hydrogen fluoride comprises:

1) concentrated hydrofluorosilicic acid (mass concentration of 48%) and first concentrated sulfuric acid (mass concentration of 85%) react in a main reactor to generate a gas containing silicon tetrafluoride and a sulfuric acid solution containing hydrogen fluoride; the temperature of the product solution after the reaction is 110° C., and the mass concentration of sulfuric acid in the product solution is 80%;

2) the silicon tetrafluoride gas is introduced into a silicon tetrafluoride generating device;

Passing the first part of the sulfuric acid solution containing hydrogen fluoride into a distillation device for separation, passing the separated hydrogen fluoride gas into a hydrogen fluoride generation device (the treatment temperature is 70° C., and the mass concentration of sulfuric acid is 85%) to remove moisture, and collecting to obtain dry crude hydrogen fluoride gas;

The crude hydrogen fluoride gas is mixed with the sulfuric acid solution in the pre-purification zone (in the pre-purification zone, the temperature of the HF gas is 70-80° C., and the temperature of the recovered sulfuric acid is 60-100° C.), and pre-purified to obtain pre-purified hydrogen fluoride gas;

Condensing the pre-purified hydrogen fluoride gas in a condensing tower, and rectifying it in a rectifying tower to obtain purified hydrogen fluoride gas and light component gas; the light component gas generated in the rectification process is transported to a hydrogen fluoride recovery device; the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device; the hydrogen fluoride gas in the hydrogen fluoride recovery device is transported to a silicon tetrafluoride generation device for drying; the sulfuric acid solution obtained by the condensation is reused in a hydrogen fluoride generation device;

The initial concentrated sulfuric acid flows through a silicon tetrafluoride generating device (the treatment temperature is 70° C., and the mass concentration of sulfuric acid is 98%) and a hydrogen fluoride recovery device (the treatment temperature is 120-160° C., and the mass concentration of sulfuric acid is 70%) in sequence, and is mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery device to dry and/or absorb one or more gases in the silicon tetrafluoride generating device and the hydrogen fluoride recovery device;

The volume ratio of the first part of the sulfuric acid solution containing hydrogen fluoride to the second part of the sulfuric acid solution containing hydrogen fluoride is 2:1.

The diluted sulfuric acid solution after treatment by the hydrogen fluoride recovery device is returned to the main reaction device.

Through calculation and detection, the yield of purified hydrogen fluoride obtained by the distillation tower is 97.9% and the purity is 99.99%.

Example 5

The production process of this embodiment is the same as that of embodiment 2, except that: the mass concentration of concentrated hydrosilicic acid is 30%, the temperature of the product solution after the reaction is 120° C., and the mass concentration of sulfuric acid in the product solution is 65%; the treatment temperature of the initial concentrated sulfuric acid flowing through the silicon tetrafluoride generating device is 60° C., and the temperature of the hydrogen fluoride generating device is 70° C.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 97.5% and the purity was 99.99%.

Example 6

The production process of this embodiment is the same as that of embodiment 2, except that: the mass concentration of concentrated hydrosilicic acid is 30%, the temperature of the product solution after the reaction is 90° C., and the mass concentration of sulfuric acid in the product solution is 70%; the treatment temperature of the initial concentrated sulfuric acid flowing through the silicon tetrafluoride generating device is 50° C., and the sulfuric acid treatment temperature of the hydrogen fluoride generating device is 80° C.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 98.3% and the purity was 99.99%.

Example 7

The production process of this embodiment is the same as that of embodiment 2, except that: the mass concentration of concentrated hydrosilicic acid is 45%, the temperature of the product solution after the reaction is 100° C., and the mass concentration of sulfuric acid in the product solution is 70%; the treatment temperature of the initial concentrated sulfuric acid flowing through the silicon tetrafluoride generating device is 110° C., and the sulfuric acid treatment temperature of the hydrogen fluoride generating device is 100° C.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 98.9% and the purity was 99.99%.

Example 8

The production process of this embodiment is the same as that of Embodiment 6, except that: in the product solution, the mass concentration of sulfuric acid is 85%; and the volume ratio of the first part of sulfuric acid solution containing hydrogen fluoride to the second part of sulfuric acid solution containing hydrogen fluoride is 1:1.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 97.5% and the purity was 99.99%.

Example 9

The production process of this embodiment is the same as that of Embodiment 8, except that the volume ratio of the first part of sulfuric acid solution containing hydrogen fluoride to the second part of sulfuric acid solution containing hydrogen fluoride is 3:1.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 98.6% and the purity was 99.99%.

Example 10

The production process of this embodiment is the same as that of Embodiment 9, except that the mass concentration of concentrated hydrofluorosilicic acid is 50%, and the volume ratio of the first part of sulfuric acid solution containing hydrogen fluoride to the second part of sulfuric acid solution containing hydrogen fluoride is 1:2.

The yield of the purified hydrogen fluoride gas was calculated and tested to be 98.1% and the purity was 99.99%.

The relevant data of the above embodiment are shown in Table 1.

Table 1 Related parameters and effects of Examples 1 to 9

The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims (12)

1. A production method for hydrogen fluoride, comprising the following steps: A) fluosilicic acid and the first concentrated sulfuric acid react in the main reaction zone to generate silicon tetrafluoride gas and sulfuric acid solution containing hydrogen fluoride; B) the silicon tetrafluoride gas is passed into the silicon tetrafluoride generation area; The sulfuric acid solution containing hydrogen fluoride is split to form at least two paths for preparing hydrogen fluoride gas; wherein: Pass the first part of the sulfuric acid solution containing hydrogen fluoride into the distillation zone for separation, pass the separated hydrogen fluoride gas into the hydrogen fluoride generation zone to remove water, and collect dry crude hydrogen fluoride gas; The second part of the sulfuric acid solution containing hydrogen fluoride is heated and passed into the mixing zone with the second concentrated sulfuric acid, and the diluted sulfuric acid solution after the mixing treatment is used as a raw material and returned to the main reaction zone. 2. The production method according to claim 1, characterized in that, in step B), the mixing zone comprises a silicon tetrafluoride generation zone; The second concentrated sulfuric acid flows through the silicon tetrafluoride generation area and is mixed with the second part of the hydrogen fluoride-containing sulfuric acid solution and then returned to the main reaction area for drying and/or absorbing one in the silicon tetrafluoride generation area. one or more gases; The temperature of the silicon tetrafluoride generation zone is 20-120°C. 3. production method according to claim 2, is characterized in that, in step B), after described distillation zone is separated, also comprises: Stripping the distillation mother liquor obtained from separation in the distillation zone to obtain high-temperature hydrogen fluoride gas and transporting it to the silicon tetrafluoride production zone. 4. The production method according to claim 2 or 3, characterized in that, in step B), after obtaining the crude hydrogen fluoride gas, it also includes: Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas; The light gas produced in the rectification process is transported to the hydrogen fluoride generation area. 5. production method according to claim 1, is characterized in that, step B) in, described mixed area comprises silicon tetrafluoride generation area and hydrogen fluoride recovery area independently separately; Described the second concentrated sulfuric acid flows through four The silicon fluoride generation area and the hydrogen fluoride recovery area are mixed with the second part of the sulfuric acid solution containing hydrogen fluoride in the hydrogen fluoride recovery area and then reused in the main reaction area for drying and/or absorption of the silicon tetrafluoride generation area and hydrogen fluoride one or more gases in the recovery zone; The temperature of the silicon tetrafluoride generation area is 20-120°C; the temperature of the hydrogen fluoride recovery area is 100-200°C. 6. production method according to claim 5, is characterized in that, in step B), after described distillation zone separates, also comprises: Stripping the distillation mother liquor separated from the distillation zone to obtain high-temperature hydrogen fluoride gas and transporting it to the hydrogen fluoride recovery zone; The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the silicon tetrafluoride generation zone for absorption. 7. The production method according to claim 5 or 6, characterized in that, in step B), after obtaining the crude hydrogen fluoride gas, it also includes: Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas; The light component gas produced in the rectification process is sent to the hydrogen fluoride recovery area. 8. production method according to claim 1, is characterized in that, step B) in, described mixing zone comprises silicon tetrafluoride generation zone independently, hydrogen fluoride recovery zone and hydrogen fluoride absorption zone; The second concentrated sulfuric acid At the same time, it flows through the silicon tetrafluoride generation area and the hydrogen fluoride absorption area to form two parallel flow paths; The sulfuric acid solution flowing out from the silicon tetrafluoride generation area and the second part of the sulfuric acid solution containing hydrogen fluoride are mixed in the hydrogen fluoride recovery area and then reused in the main reaction area for drying and/or absorption of the silicon tetrafluoride generation area and hydrogen fluoride One or more gases in the recovery zone; The sulfuric acid solution flowing out from the hydrogen fluoride absorption zone is mixed with the sulfuric acid solution in the hydrogen fluoride production zone and then returned to the main reaction zone for drying and/or absorption of one or more gases in the hydrogen fluoride absorption zone and the hydrogen fluoride production zone; The temperature of the silicon tetrafluoride generation zone is 20-120°C; the temperature of the hydrogen fluoride recovery zone is 100-200°C; the temperature of the hydrogen fluoride absorption zone is 10-140°C. 9. production method according to claim 8, is characterized in that, after described distillation zone is separated, also comprises: Stripping the distillation mother liquor separated from the distillation zone to obtain high-temperature hydrogen fluoride gas and transporting it to the hydrogen fluoride recovery zone; The hydrogen fluoride gas in the hydrogen fluoride recovery zone is transported to the hydrogen fluoride absorption zone for absorption. 10. The production method according to claim 8 or 9, characterized in that, in step B), after obtaining the crude hydrogen fluoride gas, it also includes: Condensing and rectifying the crude hydrogen fluoride gas to obtain purified hydrogen fluoride gas; The light component gas produced in the rectification process is sent to the hydrogen fluoride recovery area. 11. The production method according to claim 2, 5 or 8, characterized in that, in step A), the mass concentration of fluosilicic acid in the main reaction zone is 30% to 55%, and the mass concentration of the first concentrated sulfuric acid The concentration is 65%-95%, and the reaction temperature is 80-130°C; In step B), the mass concentration of the second concentrated sulfuric acid is 96-98%. 12. A production system for hydrogen fluoride, comprising: The main reaction device is used to add fluosilicic acid and the first concentrated sulfuric acid for mixed reaction, and discharge gas products and liquid products; the main reaction device is provided with at least two liquid outlets; Distillation device, used to separate the hydrogen fluoride gas in part of the fluorine-containing sulfuric acid discharged from the main reaction device; the distillation device is connected to one of the liquid outlets of the main reaction device; The mixing device includes a hydrogen fluoride generating device to prepare crude hydrogen fluoride gas; the mixing device is connected to each liquid outlet and sulfuric acid inlet of the main reaction device, and is used to mix sulfuric acid in different sections and return it to the main reaction device , in order to realize sulfuric acid cycle treatment of hydrogen fluoride gas.

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