阅读说明：本技术 利用真空膜分离技术分离浓缩含氟水蒸气的方法 (Method for separating and concentrating fluorine-containing water vapor by utilizing vacuum membrane separation technology ) 是由 朱静 欧建 刘松林 隋岩峰 史连军 杨帆 李天祥 于 2021-09-06 设计创作，主要内容包括：本发明提供了一种利用真空膜分离技术分离浓缩含氟水蒸气的方法。该方法的步骤包括：(1)原料含氟水蒸汽从膜组件的入口端进入,经过膜分离作用,含氟水蒸汽的浓缩汽从膜组件出口流出,含少量氟化氢的大量水蒸汽从膜侧口渗透侧流出；(2)所述原料含氟水蒸汽的浓度为0.1%-5%,浓缩含氟水蒸汽的浓缩汽浓度1%-30%,含少量氟的水蒸汽渗透汽的浓度为0.2%-3%；(3)水蒸汽温度控制在50-120℃,流量为0.1-10 L??min～(-1)；热空气温度在50-120℃,流速在0.10-10 L??min～(-1)；渗余侧和渗透侧压力均为0.01-0.1MPa；膜内外压差为0.005MPa-0.06MPa。本发明的工艺简单,能耗低。(The invention provides a method for separating and concentrating fluorine-containing water vapor by utilizing a vacuum membrane separation technology. The method comprises the following steps: (1) raw material fluorine-containing water vapor enters from the inlet end of the membrane component, concentrated vapor of the fluorine-containing water vapor flows out from the outlet of the membrane component through the membrane separation effect, and a large amount of water vapor containing a small amount of hydrogen fluoride flows out from the permeation side of the membrane side port; (2) the concentration of the fluorine-containing water vapor of the raw material is 0.1-5%, the concentration of the concentrated steam of the concentrated fluorine-containing water vapor is 1-30%, and the concentration of the water vapor permeating steam containing a small amount of fluorine is 0.2-3%; (3) the temperature of the steam is controlled at 50-120 deg.C, and the flow rate is 0.1-10L ∙ min ‑1 (ii) a The hot air temperature is 50-120 deg.C, and the flow rate is 0.10-10L ∙ min ‑1 (ii) a The pressure of the retentate side and the pressure of the permeate side are both 0.01-0.1 MPa; the pressure difference between the inside and the outside of the membrane is 0.005MPa-0.06 MPa. Hair brushThe method has simple process and low energy consumption.)

1. A method for separating and concentrating fluorine-containing water vapor by using a vacuum membrane separation technology is characterized by comprising the following steps:

(1) raw material low-concentration fluorine-containing water vapor is fed from an inlet of the membrane separation equipment and is subjected to membrane separation treatment by a membrane module, concentrated vapor of the fluorine-containing water vapor flows out from an outlet of the membrane module, and water vapor containing a small amount of hydrogen fluoride flows out from a permeation side of a membrane side port;

(2) hot air is used as a carrier, the pressure difference between the retentate side and the permeate side is used as a driving force, and the raw material gas is concentrated by separating fluoride and water vapor molecules in the raw material gas through a water vapor permeation membrane.

2. The method for separating and concentrating fluorine-containing water vapor by using the vacuum membrane separation technique according to claim 1, wherein the concentration of the raw material fluorine-containing water vapor is between 0.1% and 5%.

3. The method for separating and concentrating fluorine-containing water vapor by using vacuum membrane separation technology as claimed in claim 1, wherein the temperature of the raw material fluorine-containing water vapor is 50-120 ℃ and the flow rate is 0.1-10L ∙ min^-1In the meantime.

4. The method for separating and concentrating fluorine-containing water vapor by using vacuum membrane separation technology as claimed in claim 1, wherein the temperature of the hot air is 50-120 ℃ and the flow rate is 0.10-10L ∙ min^-1In the meantime.

5. The method for separating and concentrating fluorine-containing water vapor by using a vacuum membrane separation technique according to claim 1, wherein both the retentate side pressure and the permeate side pressure are in the range of 0.01 to 0.1 MPa; the pressure difference between the inside and the outside of the membrane is 0.005MPa-0.06 MPa.

6. The method for separating and concentrating fluorine-containing water vapor according to claim 1, wherein the membrane material is a hydrophilic modified polysulfone membrane material or a polyimide membrane material.

7. The method for separating and concentrating fluorine-containing water vapor by using a vacuum membrane separation technique according to claim 1, wherein the membrane module is a hollow fiber membrane, or a wound membrane, or a flat membrane.

Technical Field

The invention belongs to the field of chemical industry, and particularly relates to the field of recycling of fluosilicic acid serving as a byproduct of a phosphating chemical industry.

Technical Field

Fluorine is an industrial raw material with wide application, and fluorine chemical products have more and more extensive application in various fields of chemical industry, medicine, biology, machinery, aerospace, military industry and the like due to the unique and excellent performance of the fluorine chemical products. Besides fluorite, phosphate rock is a fluorine resource containing the most fluorine. Over 90% of fluorine resources are associated with phosphate ore in nature, and the phosphate ore is one of the most valuable fluorine resources.

In the production process of phosphoric acid by a wet method, a part of fluorine resources can enter dilute phosphoric acid to be concentrated. During the concentration process, fluorine in the phosphoric acid escapes in the form of hydrogen fluoride and silicon tetrafluoride. If the fertilizer is directly discharged into the environment, the pollution to the atmosphere and water sources can be caused, the health of people is seriously influenced, and the growth of crops is harmed.

At present, water or alkali liquor is mostly used by phosphorization enterprises to absorb fluorine in concentrated gas, and fluosilicic acid or fluosilicate is generated for recycling, so that the fluorine is prevented from entering the atmosphere to pollute the environment and damage the health of human beings; but also can recover fluorine resources to prepare anhydrous hydrogen fluoride.

The hydrogen fluoride is used as an important chemical raw material in modern fluorine chemical industry and has wide application. If the hydrogen fluoride which escapes from the wet-process phosphoric acid concentration process can be directly separated, considerable economic benefits can be brought to enterprises. However, the fluorine-containing water vapor released from the wet-process phosphoric acid concentration process is low in total content of hydrogen fluoride and silicon tetrafluoride, which is generally between 2% and 4%, and cannot be directly utilized.

If the fluorine-containing steam escaping from the phosphoric acid concentration system can be separated and concentrated from fluoride and steam to obtain the fluorine-containing steam with relatively low water content and relatively high concentration, the fluorine-containing steam is expected to directly enter an anhydrous hydrogen fluoride production system on the basis to produce anhydrous hydrogen fluoride.

The membrane separation technology has the advantages of simple process and easy operation, and is widely applied to the fields of chemical and petrochemical industry, wastewater treatment, food industry, biotechnology, seawater desalination, natural gas dehumidification, gas separation and the like. However, because of the strong corrosiveness of hydrogen fluoride, no research on directly separating and concentrating fluorine-containing gas by using a membrane separation technology is available at present.

Disclosure of Invention

The invention provides a method for separating and concentrating fluorine-containing water vapor by utilizing a vacuum membrane separation technology. Specifically, the method is a method for separating fluoride and water vapor in fluorine-containing water vapor by using a membrane separation technique in a vacuum state to realize concentration.

The technical scheme adopted by the invention is as follows: a method for separating and concentrating fluorine-containing water vapor by using a vacuum membrane separation technology comprises the following steps:

(1) raw material low-concentration fluorine-containing water vapor is fed from an inlet of the membrane separation equipment and is subjected to membrane separation treatment by a membrane module, concentrated vapor of the fluorine-containing water vapor flows out from an outlet of the membrane module, and water vapor containing a small amount of hydrogen fluoride flows out from a permeation side of a membrane side port;

(2) hot air is used as a carrier, the pressure difference between the retentate side and the permeate side is used as a driving force, and the raw material gas is concentrated by separating fluoride and water vapor molecules in the raw material gas through a water vapor permeation membrane.

In the method, the fluorine-containing water vapor concentration of the raw material is 0.1-5%, the temperature is 50-120 ℃, and the flow rate is 0.1-10L ∙ min^-1To (c) to (d);

in the method, the temperature of hot air is 50-120 deg.C, and the flow rate is 0.10-10L ∙ min^-1To (c) to (d);

in the method, the pressure of the retentate side and the pressure of the permeate side are both 0.01-0.1 MPa; the pressure difference between the inside and the outside of the membrane is 0.005MPa-0.06 MPa;

in the above method, the membrane material is hydrophilic modified polysulfone membrane material or polyimide membrane material, and is not limited thereto; the membrane module adopts a hollow fiber membrane, or a roll membrane, or a flat membrane, and is not limited thereto.

The principle of the invention is as follows: the water vapor molecules and the hydrogen fluoride molecules can form cluster migration in the membrane through the interaction of hydrogen bonds and the surface of the hydrophilic membrane; the water molecules can also generate plasticizing and swelling effects on the polymer; increasing the water vapor permeation rate. Meanwhile, the water vapor molecules and the hydrogen fluoride molecules can also have surface diffusion, capillary condensation and the like in the porous membrane. The invention realizes the separation and concentration of water vapor molecules, hydrogen fluoride molecules and silicon tetrafluoride molecules by utilizing the property difference of mass transfer and heat transfer of the water vapor molecules, the hydrogen fluoride molecules and the silicon tetrafluoride molecules in a hydrophilic membrane.

The invention separates the fluoride and the vapor in the fluorine-containing vapor by using the membrane separation technology in a vacuum state, realizes the concentration of the fluorine-containing vapor, and has simple process and low energy consumption.

Detailed Description

Example 1

Adding 0.3031mol/L fluosilicic acid into a container, heating by a magnetic stirring electric heating sleeve under the atmospheric pressure of 0.08879MPa until the solution is boiled and decomposed to generate fluorine content w (F)^-) =0.8066% fluorine-containing water vapor. Introducing hot air with flow rate of 0.25L ∙ min-1 at 120 deg.C, feeding mixed vapor containing water vapor, hydrogen fluoride and silicon tetrafluoride into membrane filament material of modified hydrophilic polysulfone with membrane area of 1.4m²The polysulfone hollow fiber membrane module of (1) is subjected to membrane separation treatment. The membrane permeation side is connected with a gas absorption device and a vacuum device. The pressure difference between the permeation side and the retentate side was kept at 0.022 MPa. And (3) absorbing and recovering water vapor on the permeation side and the retentate side by using alkali, and finishing the experiment after 0.47 h. And analyzing and detecting the contents of fluorine, silicon, hydrogen and water in the absorption liquid. Calculated from the analysis results: the total mass of the fluorine-containing water vapor discharged from the permeation side is 62.43g, and the fluorine content is 0.2788%; the total mass of the fluorine-containing water vapor discharged from the outlet end is 7.20g, and the fluorine content is 6.55%. The fluorine-containing water vapor enters the membrane at the opposite inlet end, the fluorine content of the water vapor at the outlet end is concentrated by 7.7 times, the dehydration rate reaches 89.2 percent, and the fluorine recovery rate reaches 70.21 percent.

Example 2

Adding 0.4115mol/L fluosilicic acid into a container, heating by a magnetic stirring electric heating jacket under the pressure of 0.08879MPa until the solution is boiled and decomposed to generate fluorine content w (F)^-) Water vapor containing fluorine of = 1.1961%. The flow rate is 0.25L ∙ min^-1Feeding mixed steam of water vapor, hydrogen fluoride and silicon tetrafluoride into membrane silk material of modified hydrophilic polysulfone with membrane area of 1.4m under 120 deg.C²The polysulfone hollow fiber membrane module of (1) is subjected to membrane separation treatment. The membrane permeation side is connected with a gas absorption device and a vacuum device. The pressure difference between the permeation side and the retentate side was kept at 0.022 MPa. And (3) absorbing and recovering water vapor on the permeation side and the retentate side by using alkali, and finishing the experiment after 0.47 h. And analyzing and detecting the contents of fluorine, silicon, hydrogen and water in the absorption liquid. Calculated from the analysis results: the total mass of the fluorine-containing water vapor discharged from the permeation side is 63.33g, and the fluorine content is 0.258%; the total mass of the fluorine-containing water vapor at the outlet is 5.28g, and the fluorine content is 11.21%. The fluorine-containing water vapor enters the membrane at the opposite inlet end, the fluorine content of the water vapor at the outlet end is concentrated by 9.37 times, the dehydration rate reaches 89.19 percent, and the fluorine recovery rate reaches 80.29 percent.

Example 3

Adding 0.3031mol/L fluosilicic acid into a container, heating by a magnetic stirring electric heating jacket under the pressure of 0.08879MPa until the solution is boiled and decomposed to generate fluorine-containing water vapor with the concentration of fluorine content w (F)^-) = 0.8066%. The flow rate is 0.25L ∙ min^-1Feeding mixed vapor containing water vapor, hydrogen fluoride and silicon tetrafluoride into membrane filament made of hydrophilic polyimide and polymer material with membrane area of 1.12m²The polyimide hollow fiber membrane module of (1) is subjected to membrane separation treatment. The membrane permeation side is connected with a gas absorption device and a vacuum device. The pressure difference between the permeation side and the retentate side is kept at 0.028 MPa. And (3) absorbing and recovering water vapor on the permeation side and the retentate side by using alkali, and finishing the experiment after 0.47 h. And analyzing and detecting the contents of fluorine, silicon, hydrogen and water in the absorption liquid. Calculated from the analysis results: the total mass of the fluorine-containing water vapor discharged from the permeation side is 68.36g, and the fluorine content is 0.4560%; the total mass of the fluorine-containing water vapor at the outlet is 3.07g, and the fluorine content is 8.876%. The fluorine-containing water vapor enters the membrane from the inlet end, and the fluorine content of the water vapor at the outlet end is concentrated by 10.44 timesThe dehydration rate reaches 93.41%, and the fluorine recovery rate reaches 48.88%.

Example 4

Adding 0.2356mol/L fluosilicic acid into a container, heating by a magnetic stirring electric heating sleeve under the atmospheric pressure of 0.08879MPa until the solution is boiled and decomposed to generate fluorine-containing water vapor with the concentration of fluorine content w (F)^-) = 0.6541%. The flow rate is 0.25L ∙ min^-1Feeding mixed vapor containing water vapor, hydrogen fluoride and silicon tetrafluoride into membrane filament made of hydrophilic polyimide and polymer material with membrane area of 1.12m²The polyimide hollow fiber membrane module of (1) is subjected to membrane separation treatment. The membrane permeation side is connected with a gas absorption device and a vacuum device. The pressure difference between the permeation side and the retentate side was kept at 0.022 MPa. And (3) absorbing and recovering water vapor on the permeation side and the retentate side by using alkali, and finishing the experiment after 0.47 h. And analyzing and detecting the contents of fluorine, silicon, hydrogen and water in the absorption liquid. Calculated from the analysis results: the total mass of the fluorine-containing water vapor on the permeation side is 60.08g, and the fluorine content is 0.3253%; the total mass of the fluorine-containing water vapor at the outlet is 7.69g, and the fluorine content is 3.150%. The fluorine-containing water vapor enters the membrane at the opposite inlet end, the fluorine content of the water vapor at the outlet end is concentrated by 4.82 times, the dehydration rate reaches 86.90 percent, and the fluorine recovery rate reaches 56.05 percent.