Hydrogen fluoride acid cooling production method and system

Abstract

The invention relates to the technical field of hydrogen fluoride production, and discloses a hydrogen fluoride acid cooling production method and system, and the method comprises the following steps: (1) carrying out coarse condensation on crude HF gas; (2) introducing into a rectification acid cooler and a degassing acid cooler for cooling; (3) introducing into a condenser and condensing into liquid; (4) introducing into a rectifying tower for separation, taking crude HF liquid in a tower kettle of the rectifying tower as shell pass cooling liquid of a rectifying acid cooler, and introducing gas subjected to heat exchange vaporization into the tower kettle of the rectifying tower for circulation; (5) introducing gas at the top of the rectifying tower into a degassing tower for separation, taking crude HF liquid at the bottom of the degassing tower as shell pass cooling liquid of a degassing acid cooler, and introducing the gas subjected to heat exchange vaporization into the degassing acid cooler for circulation; and (6) obtaining a liquid HF product at the tower kettle of the degassing tower. According to the invention, the rectifying tower and the degassing tower can obtain the minimum vaporization amount and the minimum tower top condensation amount which meet the product quality requirements and are required by tower kettle liquid, so that the energy consumption is obviously reduced.

Description

Technical Field

[0001] This invention relates to the technical field of hydrogen fluoride production, and in particular to a method and system for cooling hydrogen fluoride acid production. Background Technology

[0002] In the field of hydrogen fluoride production, the existing mainstream production processes have fixed flow patterns and energy consumption characteristics. Specifically, the crude hydrogen fluoride gas produced by the reactor needs to be washed and cooled to about 100°C in a scrubbing tower, and then successively cooled to about 30°C in a crude condenser (circulating cooling water) and a primary condenser (circulating cooling water). It is then condensed into liquid and stored in a crude product tank in a secondary and tertiary condenser (-1°C chilled water). In the subsequent rectification and purification process, rectification is used to remove high-boiling substances and complete multi-stage gas-liquid mass transfer, finally obtaining high-purity hydrogen fluoride liquid at the bottom of the column.

[0003] Currently, similar acid-cooling processes in the hydrogen fluoride industry, while attempting to reduce energy consumption through optimized cooling or heat transfer methods, all suffer from significant drawbacks and fail to achieve an optimal balance between energy consumption and production efficiency. For example, patent CN207192788U discloses a hydrofluoric acid production distillation gas-phase feed device, including an acid cooler, a crude acid tank, primary and secondary condensers, a distillation column, and a distillation condenser. The acid cooler has an inlet connected to an external scrubbing tower to receive hydrogen fluoride gas. The acid cooler is connected to the primary and secondary condensers, the crude acid tank, and the distillation column. The primary and secondary condensers are connected to the crude acid tank, and the distillation condenser is connected to the distillation column. An outlet on the distillation column discharges the finished product. This device eliminates the crude condenser, attempting to achieve self-heating distillation and degassing production, but this scheme suffers from a severe imbalance between heat and cold. To alleviate the imbalance between heat and cold, the circulation of cooling acid needs to be increased. This not only increases the overall load on the system, but also leads to a significant increase in the cooling load of the chiller. Ultimately, the increased power consumption of the chiller exceeds the power consumption of the original coarse-stage condenser cooling tower and fan, resulting in an increase in energy costs.

[0004] Furthermore, in the hydrogen fluoride distillation and purification process, given fixed equipment dimensions and packing, there exists a minimum vaporization rate and a minimum condensation rate at the top of the distillation and degassing columns required to meet product quality requirements, at which point system energy consumption can be minimized. However, existing production processes and similar acid-cooling optimization processes are not designed around this minimum energy consumption condition, failing to achieve synergistic optimization of energy consumption and product quality. In summary, existing hydrogen fluoride production processes and similar acid-cooling improvements in the industry suffer from numerous drawbacks, including high energy consumption and difficulty in controlling the balance of heat and cold, making it difficult to achieve the goal of high-efficiency, low-consumption production. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method and system for cooling and producing hydrogen fluoride. By optimizing the process flow, adding specialized equipment, and precisely controlling the temperature and heat balance, the distillation and degassing columns achieve the minimum vaporization and minimum condensation rates required for the bottom liquid to meet product quality requirements (at which point energy consumption is lowest) within the existing equipment size and packing conditions. This achieves four core technical effects: significantly reduced energy consumption, efficient waste heat recovery, stable system operation, and product quality compliance.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for producing hydrogen fluoride by cooling, comprising the following steps: (1) After the crude HF gas is condensed in the crude stage, the temperature is reduced to 45-65℃; (2) Pass the acid through a distillation acid cooler to cool down to 30-35℃, and then pass it through a degassing acid cooler to cool down to 25-30℃; (3) Pass the mixture into a condenser and condense it into a liquid; (4) The crude HF liquid in the distillation column is used as the shell side cooling liquid of the distillation acid cooler, and the gas vaporized by heat exchange is circulated into the distillation column bottom. (5) The gas at the top of the distillation column is fed into the degassing column for separation. The crude HF liquid at the bottom of the degassing column is used as the shell-side coolant of the degassing acid cooler. The gas after heat exchange and vaporization is fed into the degassing acid cooler for circulation. (6) Liquid HF product is obtained in the bottom of the degassing tower.

[0007] This invention retains the coarse-stage condenser and precisely controls the temperature to match the heat and cold requirements of the tube side (crude HF gas) and the shell side (circulating cooling water), ensuring that the distillation column and degassing column obtain the "minimum vaporization amount to meet product quality" and avoiding energy waste caused by overcooling or overheating.

[0008] By recovering heat from crude HF gas using an acid cooler, the system completely replaces the functions of the distillation and degassing reboilers, achieving self-heating distillation and degassing production and significantly reducing energy costs. The distillation acid cooler and degassing acid cooler are specifically designed to meet the minimum vaporization requirements of the distillation and degassing columns, respectively. The shell side of the distillation acid cooler discharges high-boiling-point impurities (sulfuric acid, water), while the degassing acid cooler ensures that the low-boiling-point components of the finished HF liquid meet the standards, ultimately ensuring that the final product quality complies with the superior grade standard in national standard GB / T7746-2023. Simultaneously, utilizing the associative heat characteristic of crude hydrogen fluoride gas (maximum specific heat around 40℃), this high specific heat region is positioned in the cooling stage of the distillation acid cooler through process temperature control. This not only avoids the heat exchange imbalance caused by the heat transfer during cooling and nonlinear temperature differences in existing technologies but also improves the heat exchange efficiency at this point, meeting the minimum vaporization requirements of the distillation column.

[0009] Preferably, the temperature of the crude HF gas entering the tube side of the distillation acid cooler is 45-65°C, and the temperature of the crude HF gas exiting the tube side is 30-35°C; the temperature of the crude HF liquid entering the shell side of the distillation acid cooler is 25-30°C, and the temperature of the distillation acid gas exiting the shell side is 30-35°C.

[0010] Preferably, the temperature of the crude HF gas entering the tube side of the degassing acid cooler is 30-35°C, and the temperature of the crude HF gas exiting the tube side is 25-30°C; the temperature of the crude HF liquid entering the shell side of the degassing acid cooler is 19-21°C, and the temperature of the degassed acid gas exiting the shell side is 25-30°C.

[0011] The distillation acid cooler uses countercurrent heat exchange, while the degassing acid cooler uses cocurrent heat exchange.

[0012] Preferably, the temperature of the crude HF gas entering the tube side of the coarse stage condenser is 80-100°C, and the shell side coolant is circulating cooling water.

[0013] Preferably, the temperature of the crude HF liquid condensed by the condenser is 5-15℃.

[0014] Preferably, the distillation column has a top temperature of 15-20°C, a bottom temperature of 30-35°C, and a pressure of 1-3 kPa.

[0015] Preferably, the top temperature of the degassing tower is 1-5℃, the bottom temperature is 15-20℃, and the pressure is 1-3kPa.

[0016] Secondly, the present invention also provides a hydrogen fluoride production system utilizing acid cooling, the system comprising a crude condenser, a distillation acid cooler, a degassing acid cooler, a condenser, a distillation column, and a degassing column connected in sequence; the bottom outlet of the distillation column is connected to the shell-side inlet of the distillation acid cooler, and the shell-side outlet of the distillation acid cooler is connected to the bottom inlet of the distillation column; the bottom outlet of the degassing column is connected to the shell-side inlet of the degassing acid cooler, and the shell-side outlet of the degassing acid cooler is connected to the bottom inlet of the degassing column.

[0017] Preferably, the condenser includes a secondary condenser and a tertiary condenser connected in sequence; or, preferably, the condenser includes a primary condenser, a secondary condenser, and a tertiary condenser connected in sequence.

[0018] The primary condenser is designed for seasonal operation. In winter, when the circulating water temperature is ≤15℃, the primary condenser is activated to further reduce the cooling load on the secondary and tertiary condensers. In other seasons, when the water temperature is high, the primary condenser is bypassed to reduce system flow resistance and adapt to different cooling requirements.

[0019] Preferably, the system further includes a scrubbing tower; the outlet of the scrubbing tower is connected to the tube-side inlet of the coarse-stage condenser.

[0020] Preferably, the tube-side outlet of the condenser is connected to the lower inlet of the distillation column; the top outlet of the distillation column is connected to the middle inlet of the degassing column.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) By retaining the coarse-stage condenser and precisely controlling the temperature, the heat and cold demands of the tube side (coarse HF gas) and the shell side (circulating cooling water) are matched to achieve a balance between heat and cold. (2) By setting up a distillation acid cooler, a degassing acid cooler and waste heat cascade utilization, the distillation tower and degassing tower are ensured to obtain the "minimum vaporization amount to meet product quality", avoiding energy waste caused by overcooling or overheating, and the final product quality meets the superior product standard in the national standard GB / T7746-2023. (3) The first-stage condenser adopts a seasonal start-up design. When the circulating water temperature is ≤15℃ in winter, the first-stage condenser is started to further reduce the cooling load of the second-stage and third-stage condensers. When the water temperature is high in other seasons, the first-stage condenser is skipped to reduce the system flow resistance and adapt to the cooling demand of different working conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the hydrogen fluoride cooling production system of the present invention.

[0023] The attached diagram is labeled as follows: 1. Crude HF gas inlet; 2. Scrubber; 3. Crude stage condenser; 4. Cooling tower; 5. Distillation acid cooler; 6. Degassing acid cooler; 7. First-stage condenser; 8. Second-stage condenser; 9. Third-stage condenser; 10. Distillation tower; 11. Degassing tower; 12. Sulfuric acid absorption tower; 13. Crude HF tank. Detailed Implementation

[0024] The technical solution of the present invention will be illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0025] like Figure 1 As shown, the hydrogen fluoride acid cooling production system of this invention includes a washing tower 2, a crude condenser 3, a distillation acid cooler 5, a degassing acid cooler 6, a condenser, a distillation tower 10, and a degassing tower 11 connected in sequence. The boiling point of hydrogen fluoride is 19.52℃ (at standard atmospheric pressure), and the operating pressure of the entire system is -4kPa to 3kPa.

[0026] Scrubbing tower 2 is connected to the reactor. A crude HF gas inlet 1 is located at the bottom of scrubbing tower 2. The crude HF gas generated by the reactor is scrubbed and cooled by scrubbing tower 2. The resulting crude HF gas (80-100℃) is then fed into the tube side of the coarse-stage condenser 3. The shell side of the coarse-stage condenser 3 is circulatedly connected to the cooling tower 4, with circulating cooling water flowing through it. The function of the coarse-stage condenser 3 is to regulate the system's heat and cold balance.

[0027] The crude HF gas (45-65℃) exiting from the tube side of the crude condenser 3 is then fed into the tube side of the distillation acid cooler 5. The shell side of the distillation acid cooler 5 receives the crude HF liquid (25-30℃) from the bottom of distillation column 10. This crude HF liquid contains high-boiling-point impurities (sulfuric acid and water). The high-temperature liquid in the bottom of distillation column 10 first enters the distillation acid cooler 5 for heat exchange. This not only cools the crude HF gas in the tube side of the distillation acid cooler 5 but also completely vaporizes the HF in the crude HF liquid (the minimum vaporization amount required to ensure product quality in the distillation column). A quantitative amount of residue is discharged from the bottom of the shell side to remove high-boiling-point components. The completely vaporized distilled acid (30-35℃) exiting from the shell side of the distillation acid cooler 5 is circulated back into the bottom of distillation column 10. The cooled crude HF gas (30-35℃) exits from the tube side of the distillation acid cooler 5.

[0028] Crude HF gas (30-35℃) is introduced into the tube side of the degassing acid cooler 6, while the shell side of the degassing acid cooler 6 receives crude HF liquid (19-21℃) from the bottom of the degassing tower 11. The lower temperature of the liquid in the bottom of the degassing tower 11 further reduces the temperature of the crude HF gas in the tube side of the degassing acid cooler 6 and completely vaporizes the HF in the crude HF liquid in the bottom of the degassing tower 11 (the minimum vaporization amount required to ensure product quality in the degassing tower). The completely vaporized degassed acid (25-30℃) exits from the shell side of the degassing acid cooler 6 and circulates back into the bottom of the degassing tower 11. The cooled crude HF gas (25-30℃) exits from the tube side of the degassing acid cooler 6.

[0029] Afterwards, the crude HF gas (25-30℃) is introduced into the tube side of the condenser for condensation. When the circulating water temperature is low in winter (≤15℃), the condenser consists of a primary condenser 7, a secondary condenser 8, and a tertiary condenser 9. The shell side of the primary condenser 7 is connected to the cooling tower 4 in a circulating connection. The crude condenser 3 and the primary condenser 7 share a single cooling tower 4. The crude HF gas is further cooled by the primary condenser. Retaining the primary condenser during the low circulating water temperature in winter significantly reduces the cooling load on the secondary and tertiary condensers. In other seasons, the primary condenser is not used; the condenser consists of a secondary condenser 8 and a tertiary condenser 9, skipping the primary condenser and proceeding directly to the secondary condenser to reduce system flow resistance. Both the shell side of the secondary condenser 8 and the tertiary condenser 9 are circulated with chilled water ranging from -5°C to 0°C. Most of the HF is condensed into a liquid phase (5-15°C) in the secondary condenser 8, while a smaller portion is condensed into a liquid phase (1-5°C) in the tertiary condenser 9. The main function of the tertiary condenser 9 is to lower the gas temperature to control the HF content in the discharged gas, condensing as much of the HF in the crude HF gas as possible into liquid. The tube-side outlets of the primary condenser 7, secondary condenser 8, and tertiary condenser 9 are all connected to the crude HF tank 13. The crude HF tank 13 is used to store the crude HF liquid obtained after condensation (5-15°C). The crude HF tank 13 can also serve as a temporary storage tank in case of a distillation system failure.

[0030] The outlet of the crude HF tank 13 is connected to the inlet of the lower part of the distillation column 10. The crude HF liquid (5-15℃) enters the distillation column 10 for distillation to separate high-boiling-point components, ensuring that the content of high-boiling-point components in the HF gas discharged from the top of the column meets the quality requirements. The outlet of the top of the distillation column 10 is connected to the inlet of the middle part of the degassing column 11. The degassing column 11 is used for distillation to separate low-boiling-point components. The vapor outlet of the top of the degassing column 11 is connected to the sulfuric acid absorption column 12, ensuring that the content of low-boiling-point components in the HF finished liquid discharged from the bottom of the column meets the quality requirements.

[0031] Example 1 In this embodiment, the hydrogen fluoride cooling production system includes a washing tower 2, a crude condenser 3, a distillation acid cooler 5, a degassing acid cooler 6, a condenser, a distillation tower 10, and a degassing tower 11 connected in sequence.

[0032] Scrubber 2 is connected to the reactor. A crude HF gas inlet 1 is located at the bottom of scrubber 2. The crude HF gas generated by the reactor is scrubbed and cooled by scrubber 2. The bottom outlet of scrubber 2 is connected to a scrubbing circulation tank, and the outlet of the scrubbing circulation tank is connected to the middle inlet of scrubber 2. Two circulation pumps are installed on the connecting pipeline, one in operation and one on standby.

[0033] The crude HF gas obtained after washing is then fed into the tube side of the crude stage condenser 3, while the shell side is fed by circulating cooling water. There are two crude stage condensers 3, one in operation and one on standby, sharing a rooftop cooling tower 4 (circulating water cooling tower), whose function is to regulate the system's heat and cold balance.

[0034] The crude HF gas exiting the tube side of the crude stage condenser 3 is then fed into the tube side of the distillation acid cooler 5. The shell side of the distillation acid cooler 5 receives the crude HF liquid from the bottom of distillation column 10. Two distillation acid pumps, one operational and one standby, are installed on the connecting pipeline between the bottom outlet of distillation column 10 and the shell inlet of the distillation acid cooler 5. The crude HF liquid in the bottom of distillation column 10 contains high-boiling-point impurities (sulfuric acid and water). Due to its high temperature, the liquid first enters the distillation acid cooler 5 for heat exchange. This not only cools the crude HF gas in the tube side of the distillation acid cooler 5 but also completely vaporizes the HF in the crude HF liquid (the minimum vaporization amount required to ensure product quality in the distillation column). A quantitative amount of residue is discharged from the bottom of the shell side to remove high-boiling-point components. The completely vaporized distillation acid from the shell side of the distillation acid cooler 5 is circulated back into the bottom of distillation column 10, while the cooled crude HF gas exits from the tube side of the distillation acid cooler 5.

[0035] Crude HF gas is introduced into the tube side of the degassing acid cooler 6, while the shell side of the degassing acid cooler 6 receives the crude HF liquid from the bottom of the degassing tower 11. Two degassing acid pumps are installed on the connecting pipeline between the bottom outlet of the degassing tower 11 and the shell inlet of the degassing acid cooler 6, one in operation and one on standby. The low liquid temperature in the bottom of the degassing tower 11 further reduces the temperature of the crude HF gas in the tube side of the degassing acid cooler 6 and completely vaporizes the HF in the crude HF liquid in the bottom of the degassing tower 11 (the minimum vaporization amount required by the degassing tower to ensure product quality). The completely vaporized degassing acid exits from the shell side of the degassing acid cooler 6 and circulates back into the bottom of the degassing tower 11, while the cooled crude HF gas exits from the tube side of the degassing acid cooler 6.

[0036] Next, the crude HF gas is introduced into the tube side of the condenser for condensation. The condenser includes a primary condenser 7, a secondary condenser 8, and a tertiary condenser 9. The shell side of the primary condenser 7 is connected to the cooling tower 4 in a loop. The crude condenser 3 and the primary condenser 7 share a cooling tower 4. The shell sides of the secondary condenser 8 and the tertiary condenser 9 are filled with chilled water. The tube side outlets of the primary condenser 7, secondary condenser 8, and tertiary condenser 9 are all connected to the crude HF tank 13, which is used to store the crude HF liquid obtained after condensation.

[0037] The outlet of the crude HF tank is connected to the inlet at the lower part of the distillation column 10. Crude HF liquid enters the distillation column 10 for distillation separation of high-boiling-point components, ensuring that the high-boiling-point component content in the HF gas discharged from the top of the column meets quality requirements. The outlet at the top of the distillation column 10 is connected to the inlet at the middle of the degassing column 11. The degassing column 11 is used for distillation separation of low-boiling-point components. The vapor outlet at the top of the degassing column 11 is connected to the sulfuric acid absorption column 12, ensuring that the low-boiling-point component content in the HF finished liquid discharged from the bottom of the column meets quality requirements.

[0038] The method for producing hydrogen fluoride using the above system (excluding winter seasons) includes the following steps: (1) The crude HF gas (175±2℃) is passed into the scrubbing tower for scrubbing and cooling to 95±2℃; then it is passed into the crude stage condenser for cooling to 60±2℃. (2) The crude HF gas (60±2℃) coming out of the tube side of the crude condenser is then fed into the tube side of the distillation acid cooler. The crude HF liquid (28±1℃) coming into the bottom of the distillation column comes into the shell side of the distillation acid cooler. The completely vaporized distillation acid (34±1℃) coming out of the shell side of the distillation acid cooler is fed into the bottom of the distillation column for circulation. The cooled crude HF gas (34±1℃) coming out of the tube side of the distillation acid cooler. (3) The crude HF gas (34±1℃) is introduced into the tube side of the degassing acid cooler, the crude HF liquid (20±1℃) is introduced into the shell side of the degassing acid cooler, the completely vaporized degassing acid (27±1℃) is introduced into the shell side of the degassing acid cooler and circulated into the degassing tower, and the cooled crude HF gas (28±1℃) is introduced into the tube side of the degassing acid cooler. (4) Crude HF gas (28±1℃) is sequentially fed into the tube side of the secondary condenser and the tertiary condenser for condensation. The shell side is fed with -1℃ chilled water. The tube side of the secondary condenser is filled with crude HF liquid at a temperature of 10±1℃ after condensation, and the tube side of the tertiary condenser is filled with crude HF liquid at a temperature of 3±1℃ after condensation. The crude HF liquid is fed into the crude HF tank for storage at a temperature of 10±1℃. (5) The crude HF liquid (10±1℃) is fed into the distillation column for distillation to separate the high-boiling-point components. The temperature at the top of the column is 20±1℃, the temperature at the bottom of the column is 28±1℃, and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the distillation column is used as the shell-side cooling liquid of the distillation acid cooler. The distillation acid gas vaporized by heat exchange is fed into the bottom of the distillation column for circulation. (6) The gas at the top of the distillation column (20±1℃) is introduced into the degassing column to separate the low-boiling-point components. The temperature at the top of the degassing column is (2±1℃), the temperature at the bottom of the column is (20±1℃), and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the degassing column is used as the shell-side cooling liquid of the degassing acid cooler. The degassing acid gas after heat exchange and vaporization is introduced into the degassing acid cooler for circulation. (7) After multiple cycles and gas-liquid mass transfer, a high-purity liquid product with HF content of 99.99% was finally obtained in the bottom of the degassing tower.

[0039] Example 2 The system used in this embodiment is the same as that in Embodiment 1. The only difference in the hydrogen fluoride production method is the use of a single-stage condenser.

[0040] The method for producing hydrogen fluoride using the system in this embodiment (in winter, the circulating water temperature is ≤15℃) includes the following steps: (1) The crude HF gas (175±2℃) is passed into the scrubbing tower for scrubbing and cooling to 95±2℃; then it is passed into the crude stage condenser for cooling to 60±2℃. (2) The crude HF gas (60±2℃) coming out of the tube side of the crude condenser is then fed into the tube side of the distillation acid cooler. The crude HF liquid (28±1℃) coming into the bottom of the distillation column comes into the shell side of the distillation acid cooler. The completely vaporized distillation acid (34±1℃) coming out of the shell side of the distillation acid cooler is fed into the bottom of the distillation column for circulation. The cooled crude HF gas (34±1℃) coming out of the tube side of the distillation acid cooler. (3) The crude HF gas (34±1℃) is introduced into the tube side of the degassing acid cooler, the crude HF liquid (20±1℃) is introduced into the shell side of the degassing acid cooler, the completely vaporized degassing acid (27±1℃) is introduced into the shell side of the degassing acid cooler and circulated into the degassing tower, and the cooled crude HF gas (28±1℃) is introduced into the tube side of the degassing acid cooler. (4) Crude HF gas (28±1℃) is sequentially fed into the tube side of the first-stage condenser, the second-stage condenser and the third-stage condenser for condensation. The shell side of the first-stage condenser is fed with circulating cooling water at <15℃, and the shell side of the second-stage and third-stage condensers is fed with chilled water at -1℃. The tube side of the first-stage condenser outputs crude HF liquid at a temperature of 18±1℃ after condensation, the tube side of the second-stage condenser outputs crude HF liquid at a temperature of 10±1℃ after condensation, and the tube side of the third-stage condenser outputs crude HF liquid at a temperature of 3±1℃ after condensation. The crude HF liquid is fed into the crude HF tank for storage at a temperature of 10±1℃. (5) The crude HF liquid (10±1℃) is fed into the distillation column for distillation to separate the high-boiling-point components. The temperature at the top of the column is 20±1℃, the temperature at the bottom of the column is 28±1℃, and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the distillation column is used as the shell-side cooling liquid of the distillation acid cooler. The distillation acid gas vaporized by heat exchange is fed into the bottom of the distillation column for circulation. (6) The gas at the top of the distillation column (20±1℃) is introduced into the degassing column to separate the low-boiling-point components. The temperature at the top of the degassing column is (2±1℃), the temperature at the bottom of the column is (20±1℃), and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the degassing column is used as the shell-side cooling liquid of the degassing acid cooler. The degassing acid gas after heat exchange and vaporization is introduced into the degassing acid cooler for circulation. (7) After multiple cycles and gas-liquid mass transfer, a high-purity liquid product with HF content of 99.99% was finally obtained in the bottom of the degassing tower.

[0041] Comparative Example 1 This comparative example uses an existing hydrogen fluoride production system, which includes a washing tower, a crude condenser, a primary condenser, a secondary condenser, a tertiary condenser, a distillation tower, and a degassing tower connected in sequence.

[0042] The scrubbing tower is connected to the reactor. A crude HF gas inlet is located at the bottom of the scrubbing tower. The crude HF gas generated by the reactor is scrubbed and cooled by the scrubbing tower. The bottom outlet of the scrubbing tower is connected to the scrubbing circulation tank, and the outlet of the scrubbing circulation tank is connected to the middle inlet of the scrubbing tower. Two circulation pumps are installed on the connecting pipeline, one operating and one on standby.

[0043] The crude HF gas obtained after washing is then fed into the tube side of the crude stage condenser, while the shell side is fed by circulating cooling water. There are two crude stage condensers, one in operation and one on standby. The crude HF gas exiting the crude stage condenser then enters the primary stage condenser. The crude stage and primary stage condensers share two air cooling towers (circulating water cooling towers) on the first floor, the function of which is to cool the gas in the system as much as possible.

[0044] The crude HF gas is sequentially fed into a secondary condenser and a tertiary condenser for condensation. Chilled water is introduced into the shell side of both condensers to condense the HF in the crude HF gas into liquid. The crude HF liquid obtained after condensation in the secondary and tertiary condensers is then stored in the crude HF tank.

[0045] The outlet of the crude HF tank is connected to the inlet at the lower part of the distillation column. Crude HF liquid enters the distillation column for distillation to separate high-boiling-point components. The distillation column is cooled by a reboiler at the bottom (heated by hot water) and a condenser at the top (cooled by -1°C chilled water), allowing for multi-stage gas-liquid mass transfer within the column to remove high-boiling-point components at the bottom. The outlet at the top of the distillation column is connected to the inlet at the middle of the degassing column. The degassing column is cooled by a reboiler at the bottom (heated by hot water) and a condenser at the top (cooled by -1°C chilled water), allowing for multi-stage gas-liquid mass transfer within the column to remove low-boiling-point components, resulting in high-purity hydrogen fluoride liquid at the bottom.

[0046] The method for producing hydrogen fluoride using the system in this comparative example includes the following steps: (1) Pass the crude HF gas (175±2℃) into the scrubbing tower for scrubbing and cooling, and cool it down to 95±2℃; (2) Pass the crude HF gas (95±2℃) into the crude stage condenser to cool it down to 34±2℃; (3) The crude HF gas (36±2℃) coming out of the tube side of the crude stage condenser is introduced into the first stage condenser, and the crude HF gas with a condensed temperature of 34±2℃ comes out of the tube side of the first stage condenser. (4) Crude HF gas (34±2℃) is sequentially passed into the tube side of the secondary condenser and the tertiary condenser for condensation. Chilled water at -1℃ is passed into the shell side of both condensers. Crude HF liquid with a condensation temperature of 10±1℃ exits from the tube side of the secondary condenser and crude HF liquid with a condensation temperature of 3±1℃ exits from the tube side of the tertiary condenser. The crude HF liquid is passed into the crude HF tank for storage at a temperature of 10±1℃. (5) The crude HF liquid (10±1℃) is fed into a distillation column for distillation to separate the high-boiling-point components. The temperature at the top of the column is 20±1℃, the temperature at the bottom of the column is 28±1℃, and the pressure of the column is 1-3kPa. (6) The gas (20±1℃) at the top of the distillation column 10 is introduced into the degassing column 11 to separate the low-boiling components. The temperature at the top of the degassing column is (2±1℃), the temperature at the bottom of the column is (20±1℃), and the pressure of the column is 1-3kPa. (7) Finally, a high-purity liquid product with HF content of 99.99% was obtained in the bottom of the degassing tower.

[0047] The systems and processes in Examples 1-2 are compared with those in Comparative Example 1 as follows: In Comparative Example 1, the cooling tower (circulating water cooling tower) is 300m². 3 Two units are used per hour, each with a cooling fan power of 11kW; circulating water pump flow rate: 400m³ / h. 3 / h, head: 70m, power: 75kW, one in operation and one on standby. The heat exchange of the crude stage and the first-stage condenser is about 700,000 kcal / h, and the heat exchange of the reboiler of the distillation column and the degassing column is about 600,000 kcal / h. The heat of the hot water in the reboiler is provided by the waste heat flue gas of the reactor at 400℃ through the gas-water heat exchanger.

[0048] In Examples 1-2, the cooling tower (circulating water cooling tower) is 150m. 3 One unit is used per hour; cooling fan power is 4kW; circulating water pump flow rate: 100m³ / h. 3 / h, head: 12.5m, power: 5.5kW, one in operation and one on standby. Distillation acid pump flow rate: 6.3m³ / h 3 / h, head: 30m, power: 3kW, one in operation and one on standby; degassing acid pump flow rate: 6.3m³ / h 3 / h, head: 30m, power: 3kW, one in operation and one on standby. Furthermore, the waste heat flue gas can be diverted to the fluorite powder drying system for utilization (saving 110m³ / hour of natural gas). 3 ).

[0049] Therefore, after adopting the acid cooling process of this invention, the original process (Comparative Example 1) uses circulating water cooling for the coarse stage condensation and primary stage condensation, which is greatly affected by seasonal temperature. In high-temperature seasons, the exhaust temperature can only be reduced to about 34°C. In the acid cooling process of this invention (Examples 1-2), the temperature of the distillation and degassing acid liquid is not affected by the season, and the distillation tower and degassing tower save 600,000 kcal / h in energy. Moreover, the heat exchange of the coarse stage condensation is reduced and the temperature difference between the tube-side gas and the shell-side cooling water of the coarse stage condensation is increased, so the water circulation volume of the cooling tower can be reduced, and the pump head and flow rate are also significantly reduced, saving 69 kW of electricity for the cooling tower and circulating water pump.

[0050] Comparative Example 2 The comparative example uses the same system as Example 1, except that the crude HF gas is cooled to 36±2℃ through a crude stage condenser.

[0051] The method for producing hydrogen fluoride using the system in Example 1 (excluding winter seasons) includes the following steps: (1) The crude HF gas (175±2℃) is passed into the scrubbing tower for scrubbing and cooling to 95±2℃; then it is passed into the crude stage condenser for cooling to 36±2℃. (2) The crude HF gas (36±2℃) coming out of the tube side of the crude condenser is then fed into the tube side of the distillation acid cooler. The crude HF liquid (28±1℃) coming into the bottom of the distillation column comes into the shell side of the distillation acid cooler. The incompletely vaporized distillation acid (34±1℃) coming out of the shell side of the distillation acid cooler is fed into the bottom of the distillation column for circulation. The cooled crude HF gas (34±1℃) coming out of the tube side of the distillation acid cooler. (3) The crude HF gas (34±1℃) is introduced into the tube side of the degassing acid cooler, the crude HF liquid (20±1℃) is introduced into the shell side of the degassing acid cooler, the completely vaporized degassing acid (27±1℃) is introduced into the shell side of the degassing acid cooler and circulated into the degassing tower, and the cooled crude HF gas (28±1℃) is introduced into the tube side of the degassing acid cooler. (4) Crude HF gas (26±1℃) is sequentially fed into the tube side of the secondary condenser and the tertiary condenser for condensation. The shell side is fed with -1℃ chilled water. The tube side of the secondary condenser is filled with crude HF liquid at a temperature of 10±1℃ after condensation, and the tube side of the tertiary condenser is filled with crude HF liquid at a temperature of 3±1℃ after condensation. The crude HF liquid is fed into the crude HF tank for storage at a temperature of 10±1℃. (5) The crude HF liquid (10±1℃) is fed into the distillation column for distillation to separate the high-boiling-point components. The temperature at the top of the column is 20±1℃, the temperature at the bottom of the column is 28±1℃, and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the distillation column is used as the shell-side cooling liquid of the distillation acid cooler. The distillation acid gas vaporized by heat exchange is fed into the bottom of the distillation column for circulation. (6) The gas at the top of the distillation column (20±1℃) is introduced into the degassing column to separate the low-boiling-point components. The temperature at the top of the degassing column is (2±1℃), the temperature at the bottom of the column is (20±1℃), and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the degassing column is used as the shell-side cooling liquid of the degassing acid cooler. The degassing acid gas after heat exchange and vaporization is introduced into the degassing acid cooler for circulation. (7) After multiple cycles and gas-liquid mass transfer, a high-purity liquid product with HF content of 99.99% was finally obtained in the bottom of the degassing tower.

[0052] In Comparative Example 2, the vaporization rate of the distillation acid cooler can only reach about 10% of the minimum vaporization rate required by the distillation column (a distillation reboiler is also required, with waste heat hot water as the heat source). The vaporization rate of the degassing acid cooler, however, can reach 100% of the minimum vaporization rate required by the degassing column. Comparative Example 2 saves 150,000 kcal / hour more energy than the distillation and degassing columns in Comparative Example 1, while Example 1 saves 600,000 kcal / hour more energy than the distillation and degassing columns in Comparative Example 1. Therefore, in this invention, the temperature of the crude HF gas after crude stage condensation cannot be too low. Only by controlling the temperature within a suitable range can the minimum vaporization rate required for distillation and degassing be achieved, and energy waste caused by overcooling be avoided.

[0053] Comparative Example 3 The only difference between the system in this comparative example and the system in Example 1 is that a coarse-stage condenser and a first-stage condenser are not used. That is, the system includes a washing tower, a distillation acid cooler, a degassing acid cooler, a second-stage condenser, a third-stage condenser, a distillation tower, and a degassing tower connected in sequence.

[0054] The method for producing hydrogen fluoride using the system in this comparative example (year-round, four seasons) includes the following steps: The crude HF gas (175±2℃) is passed into a scrubbing tower for washing and cooling, and then cooled to 95±2℃. (2) The crude HF gas (95±2℃) coming out of the washing tower is then fed into the tube side of the distillation acid cooler. The crude HF liquid (28±1℃) in the bottom of the distillation tower enters the shell side of the distillation acid cooler. The completely vaporized distillation acid (34±1℃) comes out of the shell side of the distillation acid cooler and is circulated into the bottom of the distillation tower. The cooled crude HF gas (34±1℃) comes out of the tube side of the distillation acid cooler. (3) The crude HF gas (34±1℃) is introduced into the tube side of the degassing acid cooler, the crude HF liquid (20±1℃) is introduced into the shell side of the degassing acid cooler, the completely vaporized degassing acid (27±1℃) is introduced into the shell side of the degassing acid cooler and circulated into the degassing tower, and the cooled crude HF gas (28±1℃) is introduced into the tube side of the degassing acid cooler. (4) Crude HF gas (28±1℃) is sequentially fed into the tube side of the secondary condenser and the tertiary condenser for condensation. The shell side is fed with -1℃ chilled water. The tube side of the secondary condenser is filled with crude HF liquid at a temperature of 10±1℃ after condensation, and the tube side of the tertiary condenser is filled with crude HF liquid at a temperature of 3±1℃ after condensation. The crude HF liquid is fed into the crude HF tank for storage at a temperature of 10±1℃. (5) The crude HF liquid (10±1℃) is fed into the distillation column for distillation to separate the high-boiling-point components. The temperature at the top of the column is 20±1℃, the temperature at the bottom of the column is 28±1℃, and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the distillation column is used as the shell-side cooling liquid of the distillation acid cooler. The distillation acid gas vaporized by heat exchange is fed into the bottom of the distillation column for circulation. (6) The gas at the top of the distillation column (20±1℃) is introduced into the degassing column to separate the low-boiling-point components. The temperature at the top of the degassing column is (2±1℃), the temperature at the bottom of the column is (20±1℃), and the pressure of the column is 1-3kPa. The crude HF liquid at the bottom of the degassing column is used as the shell-side cooling liquid of the degassing acid cooler. The degassing acid gas after heat exchange and vaporization is introduced into the degassing acid cooler for circulation. (7) After multiple cycles and gas-liquid mass transfer, a high-purity liquid product with HF content of 99.99% was finally obtained in the bottom of the degassing tower.

[0055] Although Comparative Example 3 is the same as Example 1, with the distillation vaporization rate reaching 120% of the minimum vaporization rate of the distillation column, the cooling load of the second and third stage condensers increases due to the absence of a primary condenser for cooling in winter. Compared to Comparative Example 1, Comparative Example 3 saves an average of 300,000 kcal / hour of energy annually in the distillation and degassing columns, and 95 kW in the cooling tower and circulating water pump. In contrast, the process in this invention (Examples 1-2) saves an average of 600,000 kcal / hour of energy annually in the distillation and degassing columns, and 69 kW in the cooling tower and circulating water pump compared to Comparative Example 1. Therefore, by retaining the crude condenser and controlling the gas temperature, this invention not only ensures the minimum vaporization rate required for distillation and degassing but also avoids energy waste caused by overheating of the gas entering the distillation acid cooler.

[0056] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A process for the production of hydrogen fluoride acid cooling, characterized in that, The system comprises the following steps: (1) cooling the crude HF gas to 45-65℃ after rough condensation; (2) cooling to 30-35℃ by passing into a rectification acid cooler, and then cooling to 25-30℃ by passing into a degassing acid cooler; (3) condensing into liquid by passing into a condenser; (4) separating by passing into a rectification tower, taking the crude HF liquid in the tower bottom of the rectification tower as the shell side cooling liquid of the rectification acid cooler, and passing the gas after heat exchange and vaporization into the tower bottom of the rectification tower for circulation; (5) separating by passing into a degassing tower, taking the crude HF liquid in the tower bottom of the degassing tower as the shell side cooling liquid of the degassing acid cooler, and passing the gas after heat exchange and vaporization into the degassing acid cooler for circulation; (6) obtaining liquid HF product in the tower bottom of the degassing tower.

2. The method of claim 1, wherein the hydrogen fluoride acid cooling production method is characterized by, The temperature of the crude HF gas entering the tube side of the rectification acid cooler is 45-65℃, and the temperature of the crude HF gas exiting the tube side of the rectification acid cooler is 30-35℃; the temperature of the crude HF liquid entering the shell side of the rectification acid cooler is 25-30℃, and the temperature of the rectification acid gas exiting the shell side of the rectification acid cooler is 30-35℃.

3. The hydrogen fluoride acid cooling production method according to claim 1 or 2, characterized by, The temperature of the crude HF gas entering the tube side of the degassing acid cooler is 30-35℃, and the temperature of the crude HF gas exiting the tube side of the degassing acid cooler is 25-30℃; the temperature of the crude HF liquid entering the shell side of the degassing acid cooler is 19-21℃, and the temperature of the degassing acid gas exiting the shell side of the degassing acid cooler is 25-30℃.

4. The method of claim 1, wherein the hydrogen fluoride acid cooling production method is characterized by, The temperature of the crude HF gas entering the tube side of the rough condenser is 80-100℃, and the cooling liquid in the shell side is circulating cooling water.

5. The method for producing hydrogen fluoride acid cooling according to claim 1 or 4, wherein The temperature of the crude HF liquid after condensation in the condenser is 5-15℃.

6. The method of claim 1, wherein the hydrogen fluoride acid cooling production method is characterized by, The temperature at the top of the rectification tower is 15-20℃, the temperature at the bottom of the rectification tower is 25-30℃, and the tower pressure is 1-3kPa; the temperature at the top of the degassing tower is 1-5℃, the temperature at the bottom of the degassing tower is 19-21℃, and the tower pressure is 1-3kPa.

7. A system for the production of hydrogen fluoride by a process according to any one of claims 1 to 6, characterised in that The system comprises a rough condenser, a rectification acid cooler, a degassing acid cooler, a condenser, a rectification tower and a degassing tower connected in sequence; the tower bottom outlet of the rectification tower is connected to the shell side inlet of the rectification acid cooler, the shell side outlet of the rectification acid cooler is connected to the tower bottom inlet of the rectification tower; the tower bottom outlet of the degassing tower is connected to the shell side inlet of the degassing acid cooler, and the shell side outlet of the degassing acid cooler is connected to the tower bottom inlet of the degassing tower.

8. The system of claim 7, wherein, The condenser comprises a two-stage condenser and a three-stage condenser connected in sequence; the system further comprises a washing tower; the outlet of the washing tower is connected to the tube side inlet of the rough condenser.

9. The system of claim 7 or 8, wherein, The tube side outlet of the condenser is connected to the lower inlet of the rectification tower; the top outlet of the rectification tower is connected to the middle inlet of the degassing tower.

10. The system of claim 7 or 8, wherein, The system further comprises a washing tower; the outlet of the washing tower is connected to the tube side inlet of the rough condenser.

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