CN-121988128-A - Method for high-precision removal and recovery of fluoride from fluorine-containing tail gas

CN121988128ACN 121988128 ACN121988128 ACN 121988128ACN-121988128-A

Abstract

The invention discloses a method for removing and recycling fluoride from fluorine-containing tail gas with high precision, and relates to the fields of pressure swing adsorption separation, fluoride engineering and environmental protection atmosphere control. The method comprises the following steps of 1) deacidifying tail gas discharged by a fluoride production device, 2) purifying the deacidified tail gas in a pressure swing adsorption system, directly exhausting the purified gas, and returning the desorption gas rich in fluoride to a production workshop for recycling or carrying out concentrated incineration treatment after vacuumizing and regeneration. The purification method provided by the invention can be used for effectively purifying the industrial fluorine-containing tail gas, so that the treated components can be directly discharged into the atmosphere to realize standard emission, excellent environmental compatibility and environmental protection benefits are realized, and on the other hand, the raw material utilization rate is remarkably improved and the treatment pressure of a rear-end process is relieved for the production process, so that the dual optimization targets of product yield improvement and comprehensive energy consumption reduction are cooperatively realized.

Inventors

LI XU
JIAN SHANSHAN
LI YALING
Xue tianwei
TAO YUPENG
LI JIE
ZHENG HANG
CHEN PENG
LIANG LIYOU
YAO ZHONGHUA

Assignees

西南化工研究设计院有限公司

Dates

Publication Date: 20260508
Application Date: 20260204

Claims (10)

1. A method for removing and recovering fluoride from fluorine-containing tail gas with high precision, which is characterized by comprising the following steps: 1) Washing and alkali-washing the tail gas discharged by the fluoride production device by a falling film absorber and a tail gas comprehensive system to deacidify the tail gas; 2) And (2) introducing the tail gas treated in the step (1) into a pressure swing adsorption system for pressure swing adsorption purification treatment, adsorbing fluoride on the adsorbent, directly evacuating the unadsorbed purified gas, desorbing and regenerating the adsorbent in a vacuumizing mode, and returning the desorbed gas rich in fluoride to a production workshop device for reaction or concentrated incineration treatment.
2. The method for high-precision fluoride removal and recovery from fluorine-containing tail gas according to claim 1, wherein the pressure swing adsorption system is operated at an operating temperature of 0-60 ℃ in the adsorption and desorption steps, and the temperature difference between the desorption step and the adsorption step is less than 20 ℃.
3. The method for removing and recovering fluoride from fluorine-containing tail gas with high accuracy as claimed in claim 1, wherein the pressure swing adsorption system is operated at an operating pressure of 1.0 MPa gauge or less in the adsorption step.
4. A method for high-precision removal and recovery of fluoride from a fluorine-containing tail gas as set forth in claim 1, wherein a small amount of purge gas is separated from the purge gas and returned to the adsorber during desorption regeneration of the adsorbent by means of vacuum.
5. A process for the high-precision removal and recovery of fluoride from a fluorine-containing tail gas as claimed in claim 1 or 4, wherein the volume ratio of purge gas returned to the adsorber to purge gas exhausted is <15% when the adsorbent is subjected to desorption regeneration by means of evacuation.
6. The method for removing and recovering fluoride from fluorine-containing tail gas with high accuracy as claimed in claim 1, wherein the adsorbent used in the pressure swing adsorption system comprises one or more of activated alumina, activated carbon, silica gel, molecular sieve and metal organic framework adsorbent.
7. The method for removing and recovering fluoride from fluorine-containing tail gas with high accuracy as claimed in claim 6, wherein the adsorbent used in the pressure swing adsorption system comprises silica gel accounting for 10% -60% of the total adsorbent volume.
8. A method for high-precision fluoride removal and recovery from fluorine-containing tail gas as set forth in claim 1, wherein the concentration of total fluoride in the purge gas is 60 ppmv or less.
9. A process for the high-precision removal and recovery of fluoride from a fluorine-containing tail gas as set forth in claim 1, wherein said fluoride comprises one or more of a perfluorinated compound, a chlorofluorocarbon, a hydrochlorofluorocarbon and a hydrofluorocarbon.
10. A process for the high-precision removal and recovery of fluoride from a fluorine-containing tail gas as claimed in claim 1, wherein the volume ratio of purge gas evacuated to tail gas entering the pressure swing adsorption system is >80%.

Description

Method for high-precision removal and recovery of fluoride from fluorine-containing tail gas Technical Field The invention relates to the fields of pressure swing adsorption separation, fluoride engineering and environmental protection atmospheric treatment, in particular to a method for removing and recycling fluoride from fluorine-containing tail gas with high precision. Background Fluorine-containing gas, mainly including perfluoro compounds, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, etc., is widely used in fields of refrigeration, spray, foaming, solvents, semiconductor manufacturing, electric power equipment, precision instruments, etc. because of its excellent chemical and thermal stability, small surface tension, good insulation of part of gas, etc. However, most fluorine-containing gases are potent greenhouse gases with extremely high Global Warming Potential (GWP), e.g., SF 6, which can be up to 23,900 times that of CO 2, and very long life in the atmosphere, which can be thousands of years. In addition, part of fluorine-containing gas has certain toxicity and can cause irreversible damage to the ecological environment. Therefore, the disordered emission of the gases forms a long-term threat to climate change and ecological environment, so that the efficient purification and recovery treatment of the gases becomes one of key links for realizing the 'two-carbon' strategic aim. At present, the treatment technology for fluorine-containing tail gas is mainly divided into two major categories, namely a destruction method and a recovery method. Destruction methods (e.g., thermal oxidation, catalytic hydrolysis, combustion methods, etc.) aim to thoroughly decompose fluorine-containing gases. Although the method can eliminate the environmental hazard, the energy consumption is generally higher, secondary pollution is possibly generated, and valuable raw material gas cannot be recovered, so that the resource waste is caused. The recovery principle focuses on the enrichment and recovery of high-value fluorine-containing gases, with adsorption separation and absorption being the focus of research. The absorption method (such as water absorption and alkali liquor absorption) has the common problems of low efficiency, strong corrosion to equipment, possible generation of fluorine-containing wastewater and the like when treating a large amount of low-concentration waste gas. The core of the adsorption separation method is the development of efficient adsorption technology and high-performance adsorption materials. In recent years, researchers have made a certain progress in the design of adsorbents, for example, by constructing a ultramicropore structure, introducing fluorine-induced electric field gradient or precisely regulating and controlling surface polarity and other strategies, the adsorption capacity and selectivity to fluorine-containing gas are remarkably improved. However, these methods focus on the adsorbent itself and still present challenges in engineering scale-up and continuous stable operation. The pressure swing adsorption technology is used as an energy-saving and efficient gas separation technology, and has good application prospect in the field of fluorine-containing gas purification. However, in the prior art, when the high-performance adsorbent is directly combined with the pressure swing adsorption process, there are still some bottlenecks such as balance of adsorption and desorption, in order to achieve efficient separation, the adsorbent needs to have high adsorption capacity and high selectivity on the target gas at the same time, and the pressure swing adsorption process requires the adsorbent to have excellent desorption performance so as to ensure that the adsorbent can be quickly and thoroughly regenerated when the pressure changes, and maintain the cycle stability. In addition, the process and materials have poor matching, most researches focus on laboratory performance of the novel adsorption materials, but when the novel adsorption materials are applied to actual pressure swing adsorption processes, the stability, the anti-pollution capability and the engineering amplification effect of the novel adsorption materials under the actual waste gas components, humidity and long-term circulation working conditions are often not researched enough. Conventional fluorine-containing gas treatment systems (e.g., combustion) are energy intensive in terms of system energy efficiency and cost. Although the development of low-energy-consumption pressure swing adsorption technology tends to be a major trend, how to further reduce the overall energy consumption and operation cost through technological innovation, and simultaneously maintain high recovery rate and purity is a key for promoting the large-scale application of the technology. Therefore, the pressure swing adsorption purification method which integrates the high-performance adsorption material, has good proce