Boron trifluoride continuous production device and method based on fluidized bed reactor

Abstract

The invention discloses a boron trifluoride continuous production device based on a fluidized bed reactor, which is characterized by comprising a reaction unit and a separation unit which are connected, the reaction unit comprises a fluidized bed reactor, a gas supply pipeline and a solid supply pipeline, the gas supply pipeline and the solid supply pipeline are respectively connected with the fluidized bed reactor, the gas supply pipeline is used for conveying fluorine-nitrogen mixed gas to the bottom of the reaction device, and the solid supply pipeline is used for conveying boron powder to the top of the reaction device; the solid and the gas are contacted and react in the reaction device; after mixed gas reacted in the reaction unit enters the separation unit to be pressurized and condensed, condensed boron trifluoride enters a product collection device, and other uncondensed gas enters the post-treatment unit. The fluidized bed reactor is adopted, so that reaction heat can be quickly transferred, the boron powder is uniformly dispersed in the fluidized bed reactor, the safety performance is high, and high-purity boron trifluoride gas can be directly obtained.

Description

technical field [0001] The invention relates to the technical field of boron trifluoride, in particular to a method for producing boron trifluoride, in particular to a device and method for continuous production of boron trifluoride based on a fluidized bed reactor. Background technique [0002] As a special boron reagent and fluoride, boron trifluoride is widely used in organic synthesis catalysts, elemental boron production, boron fiber processing, and preparation of organic boron compounds. High-purity boron trifluoride can also be used in the electronics industry. P-type dopant source for silicon and germanium epitaxy, diffusion and ion implantation processes. [0003] my country's boron trifluoride bottled gas, including industrial grade 99.5% and electronic grade 99.999%, has been dependent on imports. In the early 1990s, in order to meet the needs of producing boron trifluoride complexes, researches on the synthesis of boron trifluoride gas were carried out. At pres...

AI Technical Summary

Problems solved by technology

This method is the most widely used, but its disadvantage is that the yield of boron trifluoride is low, the highest is less than 90%, it contains gaseous impurities such as silicon tetrafluoride, sulfur dioxide, sulfur trioxide and hydrogen fluoride, and it is difficult to remove the solid residue in the reactor , the amount of sulfuric acid is also relatively large, this process requires 18 tons of oleum for producing 1 ton of boron trifluoride gas, so the by-product sulfuric acid produced is about 20 tons, and the corrosion of equipment is relatively serious

The purity of the boron trifluoride obtained by this method is relatively high, and the purity of the product without purification can reach more than 99%, but there are still many bottlenecks in the process amplification, and hydrogen fluoride is very serious for equipment corrosion at high temperatures

[0008] (4) the method for pressurized fluorosulfonic acid and boric acid reaction, the boron trifluoride productive rate that this method produces is lower

[0009] (5) Boron directly reacts with fluorine gas, the reaction is violent, difficult to control, and the safety is poor. The boron trifluoride produced by this dry method has a high purity, and the purity of the product without purification can reach 99%.

However, it has been found in actual operation that the process is extremely difficult to control, and the time point of the two-stage reaction is also extremely difficult to grasp. The reaction time in the previous period was too long and the boron trifluoride gas was extracted at the same time, resulting in an extremely low yield; Short, a large amount of silicon tetrafluoride enters boron trifluoride, which is difficult to remove later

Even if the time point is grasped accurately, the content of silicon tetrafluoride in the actual product is also difficult to reach below the theoretical 20ppm, and the method is carried out under high temperature conditions, which consumes a lot of energy and has high production costs.

Therefore, the content of silicon tetrafluoride is controlled by the reaction process from the technical level of the prior art.

Chinese invention patent CN1121270C discloses a method for producing boron trifluoride and sulfuric acid from boron trifluoride hydrate. On the one hand, oleum is dangerous in the operation process of this method, and on the other hand, the purity of boron trifluoride is not enough. Still need to continue the purification process to meet market demand

[0011] It can be seen that the ubiquitous problems in the prior art are that the production efficiency of boron trifluoride is low, the high investment in equipment leads to high production costs, and the production of by-products and waste water leads to serious environmental pollution and other problems.

At the same time, the boron trifluoride purification process has not made further breakthroughs in technology, resulting in the domestic production of boron trifluoride being largely dependent on imports

In summary, the prior art does not yet have a preparation method capable of directly preparing boron trifluoride that meets the high-purity requirements

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