CN109019516B

CN109019516B - Tail gas absorption device for preparing hydrogen fluoride

Info

Publication number: CN109019516B
Application number: CN201811207240.3A
Authority: CN
Inventors: 杨松
Original assignee: Individual
Current assignee: Fujian Longfu New Material Co.,Ltd.
Priority date: 2018-10-17
Filing date: 2018-10-17
Publication date: 2020-07-28
Anticipated expiration: 2038-10-17
Also published as: CN109019516A

Abstract

The invention relates to the technical field of fluorine chemical industry, in particular to a hydrogen fluoride preparation tail gas absorption device. The method is characterized in that: comprises a filler absorption tower, an ammonia water spraying and washing filler tower and an alkali liquor spraying and washing filler tower.

Description

Tail gas absorption device for preparing hydrogen fluoride

Technical Field

The invention relates to the technical field of fluorine chemical industry, in particular to a hydrogen fluoride preparation tail gas absorption device.

Background

Hydrogen fluoride has been widely used in the industries of electronics, chemical industry, petroleum and the like, and is mainly used for preparing villiaumite, fluorine-halogen alkane, fluorine refrigerant, corrosion glass, wood impregnation, electrolysis of elemental fluorine and the like, wherein non-condensable gas at normal temperature and a small amount of HF are used as tail gas to be discharged to the ambient air in the technical process of obtaining hydrogen fluoride, and the non-condensable gas and the small amount of HF are mostly environmental pollutants and occupational disease hazard factors, so that the tail gas is discharged after being subjected to recovery treatment and environmental protection treatment. The Chinese invention patent (with the patent number of CN201721452592.6, the patent name is a tail gas absorption system containing hydrogen fluoride) discloses a tail gas absorption system containing hydrogen fluoride, which is characterized by comprising an absorption tower, a liquid caustic soda pool, a first circulating pump, a tubular liquid distributor, a neutralization pool and a demister; the liquid outlet of the liquid caustic soda tank is communicated with the liquid inlet of the absorption tower through a first valve, the first liquid outlet of the absorption tower is communicated with the liquid inlet of a tubular liquid distributor through a second valve and a first circulating pump, the tubular liquid distributor is transversely arranged above the inside of the absorption tower, and the second liquid outlet of the absorption tower is communicated with the neutralization tank through a third valve; the demister is transversely arranged in the absorption tower and is arranged above the tubular liquid distributor. The system repeatedly absorbs the tail gas containing the hydrogen fluoride and introduced into the absorption tower, so that the content of fluorine ions in the tail gas containing the hydrogen fluoride is greatly reduced, and the system has good environmental protection benefits. The Chinese patent of the invention (with the patent number of CN201721835228.8, the patent name is a desulphurization device for hydrogen fluoride processing tail gas) discloses a desulphurization device for hydrogen fluoride processing tail gas, and the technical scheme is as follows: including the desulfurization storehouse, desulfurization storehouse lower surface bilateral symmetry welding has balanced bottom plate, and the inside spring post that is fixed with of balanced bottom plate, the fixed surface has the guide plate under the sealed lid, sealed lid upper surface center department is fixed with the booster pump, and is connected with the air duct bottom the booster pump, the welding of sealed lid upper surface one side has the outlet duct, and the opposite side welding has the intake pipe and the supporting solenoid valve that uses with it, the welding of intake pipe surface has jet-propelled pipe, the rotation of table wall one side is connected with seal baffle in the jet-propelled pipe, and the welding of opposite side has the stopper, jet-propelled pipe upper surface welding has the diffusion storehouse, the table wall is fixed with the filter plate in the desulfurization storehouse, the welding of. The utility model discloses in, this desulphurization unit overall structure design is simple reasonable, the maximize improved desulfurated work efficiency, has stronger practicality.

Non-condensable gas or light component SO at normal temperature in the process of hydrogen fluoride according to prior art 1 and prior art 2₂、SiF₄、CO₂、H₂S and a small amount of HF do not have a complete environment-friendly treatment process, and the tail gas formed by the components is discharged to the ambient air, so that sources of environmental pollution and occupational disease hazards are caused.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a tail gas absorption device for preparing hydrogen fluoride, which is characterized in that: the tail gas is treated by the filler absorption tower, the ammonia water spraying and washing packed tower and the alkali liquor spraying and washing packed tower in sequence and then is discharged to the ambient air.

The filler absorption tower comprises a spray pipe, a distribution pipe plate, a filler, a tail gas inlet and a filler absorption tower body, wherein the spray pipe, the distribution pipe plate, the filler and the tail gas inlet are sequentially designed on the filler absorption tower body from top to bottom, and the filler absorption tower selects the recovery liquid as concentrated sulfuric acid with the mass fraction of 95-98%.

The filler is fluorgypsum filter material particles with the particle size of 2-4 mm, the fluorgypsum filter material particles are prepared from local materials, a byproduct fluorgypsum in the production process is utilized, the fluorgypsum is hardened by adding water to obtain the physical and chemical characteristics of particles with certain strength and hardness to prepare a filler absorption tower, an ammonia water spraying and washing filler tower and an alkali liquor spraying and washing filter material particles required by the filler tower, the fluorgypsum is crushed and sieved to 60 meshes, 100 parts of fluorgypsum and 80-100 parts of deionized water are mixed uniformly to prepare slurry, the slurry is pumped to a granulation tower, and the fluorgypsum filter material particles with the required particle size are prepared after drying.

The ammonia water spraying and washing packed tower and the alkali liquor spraying and washing packed tower respectively select ammonia water and NaOH alkali liquor, wherein the ammonia water is NH with the mass fraction of 8-10%₃And (3) an aqueous solution, wherein the alkali liquor is a NaOH aqueous solution with the mass fraction of 10-15%, and the filler is fluorgypsum filter material particles with the particle size of 8-10 mm.

The inventors found that fluorite (CaF) for producing hydrogen fluoride₂) And sulfuric acid (H)₂SO₄) The following main reactions occur: CaF₂+2H₂S0₄→2HF+CaSO₄The product entering the next process stage has mainly a heavy fraction H₂SO₄、H₂O, light component SO₂、SiF₄、CO₂、H₂S, by-products including CaSO₄、Fe₂(SO₄)₃、H₂SiF₆. According to the requirements of national standard GB 7746-₂SO₄、H₂O、H₂SiF₆、SO₂The content of the hydrofluoric acid is limited, and the anhydrous hydrogen fluoride is prepared by removing impurities by washing, condensing, rectifying and degassing processes by utilizing the difference of the boiling points of the components, specifically, hydrofluoric acid gas enters a washing tower from a reaction furnace for washing, after dust and water impurities are removed, the hydrofluoric acid gas enters a condensing system from the washing tower, and crude hydrofluoric acid liquid (the main component of which is a heavy component H) is formed by primary condensation through primary, secondary and tertiary condensation and primary condensation after primary condensation through primary condensation₂SO₄、H₂O) returns to the washing tower to condense and wash hydrofluoric acid gas, and crude hydrofluoric acid liquid (the main component is hydrofluoric acid) condensed from the second and third stages is sent into a degassing tower and a rectifying tower by a rectifying pump to further remove light component SO₂、SiF₄、CO₂、H₂S and heavy component H₂SO₄、H₂And O, obtaining the finished product of the anhydrous hydrogen fluoride. Wherein the heavy component H₂SO₄、H₂O is recovered and used for the non-condensable gas at normal temperature and the light component SO after rectification which are generated by three-stage condensation and required by the reaction furnace₂、SiF₄、CO₂、H₂S and a small amount of HF will be emitted as tail gas to the ambient air, where they remove CO₂Besides, the tail gas is an environmental pollutant and an occupational disease hazard factor, so the tail gas is discharged after being recycled and environmentally-friendly.

The inventors have found that SiF has a recovery value₄Can be concentrated H₂SO₄Absorption to form H₂SiF₆Concentrated H₂SO₄Adopting H with the mass fraction of 95-98%₂SO₄Due to H₂SiF₆Boiling point of 144 ℃ relative to SiF₄Belongs to a component which is difficult to volatilize, has larger boiling point difference with other tail gas components, can be well separated, and HF is easy to be concentrated H₂SO₄The water in the concentrated sulfuric acid is absorbed to generate hydrofluoric acid, so the concentrated sulfuric acid and the light components can be well recycled and well separated by utilizing the characteristic that the concentrated sulfuric acid has high boiling point and is not easy to volatilize, and the absorption process is finished under the conditions of normal temperature and normal pressure, so that the energy is saved and the consumption is reduced. In order to ensure that gas-liquid two phases can be fully transferred, the recovery device is designed into a filler absorption tower, and the filler adopts fluorgypsum filter material particles with the particle size of 2-4 mm. Concentrated sulfuric acid is dispersed from a spray pipe on the upper part of the filler absorption tower body, the concentrated sulfuric acid is uniformly distributed on the surfaces of filler particles through a distribution pipe plate, tail gas is fed from a tail gas inlet designed on the lower part of the filler absorption tower body and is subjected to countercurrent mass transfer exchange with concentrated sulfuric acid liquid on the surfaces of the filler from bottom to top, and H after recovery is finished₂SiF₆HF and concentrated H₂SO₄The liquid is collected to the bottom of the filler absorption tower body and sent into a circulating fluidized bed reaction furnace for use, in order to reduce cost, part of reflux spray pipes are recycled, the reflux ratio is designed to be 10-20% according to the ratio of the reflux amount to the output amount, and the tail gas after absorption treatment enters an ammonia water spraying and washing filler tower and an alkali liquor spraying and washing filler tower for treatment.

The inventors found that SO is treated in a packed absorber column₂、SiF₄、CO₂、H₂S, HF, respectively designing ammonia water spray washing packed tower and alkali liquor spray washing packed tower to remove the above pollutants, respectively selecting ammonia water and NaOH alkali liquor as spray liquid, wherein the ammonia water is NH with mass fraction of 8-10%₃And (3) an aqueous solution, wherein the alkali liquor is a NaOH aqueous solution with the mass fraction of 10-15%, and the filler is fluorgypsum filter material particles with the particle size of 8-10 mm.

The inventors have found that the filler can be obtained from a local source and used as a by-product in the production process, and it is known that fluorite (CaF)₂) And sulfuric acid (H)₂SO₄) The main reaction occurs: CaF₂+2H₂S0₄→2HF+CaSO₄By-product CaSO₄Is commonly known as fluorogypsum, which is naturally not H-protected as the end product of the irreversible reaction₂SO₄And HF corrosion, and realizes the recycling and comprehensive utilization of solid wastes. The main component of the fluorgypsum is anhydrous CaSO₄Granules, which harden with water by the process of: first anhydrous CaSO₄Dissolved in water and then CaSO₄.2H₂The O is separated out to form slurry, and the CaSO is generated along with the continuous progress of hydration₄.2H₂The increasing of O colloid particles, which have large specific surface area and absorb much water, and the free water in the slurry is reduced due to hydration and evaporation, the consistency of the slurry is increased, the slurry is gradually coagulated, the colloid is transformed into crystal, and the slurry is hardened. The physical and chemical characteristics of the fluorgypsum with certain strength and hardness particles can be obtained by adding water to harden the fluorgypsum to prepare filter material particles required by a filler tower, an ammonia water spraying and washing filler tower and an alkali liquor spraying and washing filler tower, the fluorgypsum is crushed and sieved to 60 meshes, 100 parts of fluorgypsum and 80-100 parts of deionized water are mixed according to the weight ratio to prepare slurry, the slurry is pumped to a granulation tower, and the fluorgypsum filter material particles with the required particle size are prepared after drying.

The inventor finds that the fluorgypsum is uniformly stirred to prepare slurry, the slurry is pumped to a spray pipe assembly, the fluorgypsum slurry is discharged from a nozzle and contracted to form spherical particles due to surface tension, meanwhile, dry fluorgypsum powder is also conveyed into a mixing chamber through a conveying pipe to wrap the slurry particles and absorb free moisture of the slurry particles, the slurry particles are intensively mixed by a Venturi pipe and a spray pipe to grow up and gradually generate condensation due to continuous reduction of moisture, the condensation is dispersed to a spray tower body along a guide cone through an outlet of the spray pipe, hot air flow blowing is carried out from an air chamber at the bottom of the spray tower and a wind distribution plate, the mixture spirally rises along the wall of the spray tower body, the cross section of the air flow is observed, the air flow forms the characteristics of high peripheral flow velocity, low central flow velocity and high peripheral pressure, the continuously growing and solidified slurry particles are thrown to the wall of the spray tower body to rub and, the slurry particles grow and solidify under the action of continuously adsorbing dry fluorgypsum powder and evaporating hot air, and after the particle size grows to a certain diameter, the particle size is gathered at the center of the spray tower body and separated from the hot air flow under the action of gravity, and the particle size enters a vibrating screen for separation through a blanking pipe; the dry fluorine gypsum powder which is not adhered to the slurry particles enters a cyclone separator under the carrying of hot air flow, the dry fluorine gypsum powder is separated from the hot air flow in the cyclone separator, and then is sent into the spray tower body again through a material returning device to be mixed with the slurry particles, the hot air flow is purified through a bag filter and then is sent into a heater to be heated, and then the hot air flow is sent into an air chamber at the bottom of the spray tower through a Roots blower to be recycled.

Compared with the prior art, the invention at least has the following advantages: firstly, non-condensable gas generated by three-stage condensation at normal temperature and light component SO after rectification₂、SiF₄、CO₂、H₂S and a small amount of HF are main components of tail gas, and a packing absorption tower is designed for SiF with recovery value₄Recovering HF, and then removing the pollutants by an ammonia water spraying and washing packed tower and an alkali liquor spraying and washing packed tower; secondly, the filler can be obtained from a local source and used as a by-product in the manufacturing process, as is well known, fluorite (CaF)₂) And sulfuric acid (H)₂SO₄) The main reaction occurs: CaF₂+2H₂S0₄→2HF+CaSO₄By-product CaSO₄Is commonly known as fluorogypsum, which is naturally not H-protected as the end product of the irreversible reaction₂SO₄And HF corrosion, and realizes the recycling and comprehensive utilization of solid wastes.

Drawings

Fig. 1 is a schematic front view of a hydrogen fluoride preparation tail gas absorption device according to the present invention.

I-filler absorption tower II-ammonia water spray washing filler tower III-alkali liquor spray washing filler tower

1-spray pipe 2-distribution pipe plate 3-filler 4-tail gas inlet

5-a filler absorption tower body.

Detailed Description

The invention is further described with reference to the following detailed description of embodiments and drawings.

As shown in fig. 1, a tail gas absorption device for preparing hydrogen fluoride is characterized in that: the tail gas is treated by the filler absorption tower I, the ammonia water spraying and washing packed tower II and the alkali liquor spraying and washing packed tower III in sequence and then is discharged to the ambient air.

The filler absorption tower I comprises a spray pipe 1, a distribution pipe plate 2, a filler 3, a tail gas inlet 4 and a filler absorption tower body 5, wherein the spray pipe 1, the distribution pipe plate 2, the filler 3 and the tail gas inlet 4 are sequentially designed on the filler absorption tower body 5 from top to bottom, and the filler absorption tower I selects the recovery liquid as concentrated sulfuric acid with the mass fraction of 95-98%.

The filler 3 is fluorgypsum filter material particles with the particle size of 2-4 mm, the fluorgypsum filter material particles are prepared from local materials, a byproduct fluorgypsum in the production process is utilized, the fluorgypsum is utilized and hardened by adding water to obtain the physical and chemical characteristics of particles with certain strength and hardness to prepare the filter material particles required by a filler absorption tower I, an ammonia water spraying and washing filler tower II and an alkali liquor spraying and washing filler tower III, the fluorgypsum is crushed and sieved to 60 meshes, 100 parts of fluorgypsum and 80-100 parts of deionized water are uniformly stirred to prepare slurry, the slurry is pumped to a granulation tower, and the fluorgypsum filter material particles with the required particle size are prepared after drying.

And respectively selecting ammonia water and NaOH alkaline liquor as spraying liquid of the ammonia water spraying and washing packed tower II and the alkaline liquor spraying and washing packed tower III, wherein the ammonia water is NH with the mass fraction of 8-10%₃And (3) an aqueous solution, wherein the alkali liquor is a NaOH aqueous solution with the mass fraction of 10-15%, and the filler is fluorgypsum filter material particles with the particle size of 8-10 mm.

Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. The utility model provides a preparation hydrogen fluoride tail gas absorbing device which characterized by: the tail gas is treated by the filler absorption tower, the ammonia water spraying and washing packed tower and the alkali liquor spraying and washing packed tower in sequence and then is discharged to the ambient air; the filler absorption tower comprises a spray pipe, a distribution pipe plate, filler, a tail gas inlet and a filler absorption tower body, wherein the spray pipe, the distribution pipe plate, the filler and the tail gas inlet are sequentially designed on the filler absorption tower body from top to bottom; selecting an absorption liquid as concentrated sulfuric acid with the mass fraction of 95-98% in the packing absorption tower; the filler of the filler absorption tower is fluorgypsum filter material particles with the particle size of 2-4 mm, the fluorgypsum filter material particles are prepared by using a byproduct fluorgypsum in the production process as a raw material, crushing and sieving the fluorgypsum to 60 meshes, uniformly stirring the fluorgypsum and 80-100 parts of deionized water according to the weight ratio to prepare slurry, pumping the slurry to a granulation tower, and drying the slurry to prepare the fluorgypsum filter material particles with the required particle size.

2. The absorption device for tail gas generated in the preparation of hydrogen fluoride according to claim 1, which is characterized in that: a process for preparing the granular filter material of fluorgypsum includes such steps as mixing fluorgypsum, stirring to obtain slurry, pumping to nozzle, delivering it from nozzle, shrinking by surface tension to become spherical particles, delivering dry fluorgypsum powder to mixing chamber, wrapping the slurry particles and absorbing its free water, mixing them by Venturi tube and spray tube, gradually coagulating while increasing the size of slurry particles, blowing by the hot air flow from bottom of spray tube and air distributing plate, spirally lifting along the wall of spray tube, and features high peripheral flow speed, low central flow speed and high central pressure, so preventing the slurry particles from falling down and accumulating, the slurry particles flow to the top of the spray tower under the wrapping of the airflow, namely the slurry particles flow in a boiling state in the spray tower body, grow up and solidify under the action of continuously adsorbing dry fluorgypsum powder and evaporating hot air, and are gathered at the center of the spray tower body after the particle size grows to a certain diameter and separated from the hot air airflow under the action of gravity, and the slurry particles enter a vibrating screen for separation through a blanking pipe; the dry fluorine gypsum powder which is not adhered to the slurry particles enters a cyclone separator under the carrying of hot air flow, the dry fluorine gypsum powder is separated from the hot air flow in the cyclone separator, and then is sent into the spray tower body again through a material returning device to be mixed with the slurry particles, the hot air flow is purified through a bag filter and then is sent into a heater to be heated, and then the hot air flow is sent into an air chamber at the bottom of the spray tower through a Roots blower to be recycled.