Method and device for preparing electronic-grade disilane

Abstract

The invention provides a method and a device for preparing electronic-grade disilane. The device mainly comprises a multi-stage low-temperature precise rectification system and a targeted adsorption system. Wherein the multi-stage low-temperature rectification system is mainly composed of multi-stage low-temperature rectification equipment, an equipment instrument and a nonlinear control theory module, the multi-stage low-temperature rectification equipment can realize process conditions which are relatively mild in relative temperature, the equipment instrument can realize precise control, and the targeted adsorption system is composed of adsorption materials suitable for adsorbing different impurity components in disilane. A crude disilane product is firstly added into a multi-stage low-temperature precision rectification system for precision rectification separation, and impurity components except for impurity components with complex physical properties such as near boiling or azeotropy and trace impurity components such as metal ions in the crude disilane product are removed, so that the variety and content of the impurity components in the crude disilane product are greatly reduced; the crude disilane product with most impurity components removed through multi-stage low-temperature precise rectification is added into the targeted adsorption system again, different special adsorption materials are used for targeted separation and removal of different impurity components, the impurity components are thoroughly removed, and high-purity electronic-grade disilane is prepared. According to the method, most of impurity components in the crude disilane product can be thoroughly removed through multi-stage low-temperature precision rectification, the variety and content of the impurity components in the crude disilane product are reduced, energy consumption can be reduced, the impurity components are thoroughly removed through different special adsorption materials, and high-purity electronic-grade disilane can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic information product preparation, and relates to silicon-based electronic special gas preparation technology, and specifically to a method and device for preparing electronic-grade disilane. Background Art

[0002] Disilane (Si2H6) is an important electronic special gas, which is widely used in the electronic information industry. Especially when used as a silicon source to make silicon films or silicon layers of electronic components, disilane has a fast deposition rate, high film uniformity, and can reduce the film forming temperature by 200-300℃ (when silane is used as the raw material, the film forming temperature is about 1000-1200℃). It has a high silicon content and obvious advantages. Therefore, electronic grade disilane is an important key material for preparing electronic information products such as chips.

[0003] As a special electronic gas, disilane has very high requirements for its purity and impurities. For example, the purity of disilane used in 14nm chip process is generally not less than 4N, and other impurity components are generally not higher than 10ppm. The purity of disilane products used in 7nm and below chip processes must reach 4N-5N or even 5N or higher, and other impurity components are generally not higher than 1ppm.

[0004] The key to preparing high-purity electronic grade disilane is separation and purification. At present, the separation and purification technologies of disilane mainly include condensation, distillation, adsorption, distillation combined with adsorption or distillation combined with membrane permeation.

[0005] The condensation separation and purification technology mainly utilizes the difference in liquefaction points of different components to condense the crude disilane raw material to liquefy components such as disilane with high liquefaction points into gas, while components with low liquefaction points such as monosilane or hydrogen remain as gas, thereby separating disilane from components such as monosilane and hydrogen. For example, patent CN201110423391.4, the process flow of this technology is relatively simple, but the condensation temperature is very low (generally not lower than -110°C), the refrigeration consumption is large, and the energy consumption is very high; at the same time, although the liquefaction points of different materials are different, the differences between many components are small, and there are also substances that are azeotropic with disilane; in addition, even if the boiling point difference is large, different components still have mutual solubility and other phenomena, and they cannot be effectively and thoroughly separated by condensation alone. Therefore, the separation effect of the condensation separation and purification technology is poor, the purity of the disilane product is low, and electronic grade high-purity disilane products cannot be produced. It basically plays the role of separation pretreatment, and other technologies are needed for further separation and purification.

[0006] The distillation separation and purification technology is to separate and purify crude disilane by heating and vaporizing the components according to their different boiling points and then condensing them, thereby removing impurity components and preparing high-purity disilane. Since crude disilane contains multiple components, there are components with higher boiling points than disilane (heavy components) and components with lower boiling points than disilane (light components) according to their different boiling points, and there are complex systems such as near-boiling or azeotropic systems. The distillation, separation and purification of crude disilane is technically difficult, and single-stage distillation cannot produce high-purity electronic-grade products, such as patents CN202220781355.9, CN202210355468.7, CN202221194527.9, CN201610469253.2 and CN201620637047.3. It is necessary to use two-stage, three-stage or even four-stage or more multi-stage distillation. For example, patents CN202022252878.8, CN201621036183.3, CN203529944U, CN205115061U, CN201320559665.7, CN201520817748.0, CN201621036191.8 and CN201621036191.8, CN202110105858.4, CN 201810907458.3, 201821282840.1, 202311511479.0, etc. use two-stage distillation to separate and purify crude disilane, and can prepare electronic-grade disilane with higher purity, but the purity is generally still low, generally not exceeding 4N, and it is basically impossible to prepare 4N and above high-purity electronic-grade disilane; in order to prepare high-purity electronic-grade disilane, patents such as CN202022131754.4, CN201621035955.1, CN206219220.9 and CN201621036182.9 use three-stage distillation, while CN202111640024.X and CN202210538469.5 use four-stage distillation. Multi-stage distillation can remove most of almost all impurity components in crude disilane, and the technology is mature. However, distillation technology cannot handle complex systems such as near-boiling or azeotropic systems; and the higher the number of distillation stages, the more distillation equipment is required and the higher the energy consumption; the more thorough the removal of components, the higher the energy consumption, especially when removing trace impurities, the energy consumption is very high; the components of crude disilane, whether it is disilane, monosilane, hydrogen or other components, have very low boiling points, the required distillation temperature is also very low, the pressure is high, the process conditions are harsh, and the distillation conditions such as distillation temperature and pressure are difficult to precisely control. At present, when using distillation technology to separate and purify crude disilane to prepare electronic-grade products, it is basically impossible to accurately control the distillation conditions, and it is difficult to separate by precise distillation, so that the components cannot be completely removed.

[0007] Adsorption technology is to use the adsorption of adsorbent materials to separate and purify crude disilane, remove impurities, and prepare disilane products with higher purity. For example, CN202022222980.3, CN202022167724.9, CN202311128024.0, CN202210026687, CN202011274073.1, CN202011620831.0, CN202220066064.1, adsorption separation can effectively remove impurities from crude disilane and prepare electronic grade disilane, especially for trace impurities. The removal effect is very obvious; adsorption separation can be carried out at room temperature, with low energy consumption and mild process conditions. However, crude disilane contains many impurities and has complex physical properties. Different impurities require different adsorption materials, but currently a single adsorption material is basically used. For example, the adsorption materials used in patents CN202022222980.3 and CN202311128024.0 are molecular sieves, and the adsorption materials used in CN202210026687 are mixed materials of activated carbon and transition metals, which cannot achieve targeted and precise adsorption and separation. In addition, it is difficult to match the adsorption material with the impurity components, the adsorption material development technology requires high requirements, the price is expensive, and the production cost is high.

[0008] It is generally difficult to separate and purify crude disilane and prepare high-purity electronic-grade disilane using a single separation and purification technology. Currently, multiple technologies are often used for coordinated processing.

[0009] For example, patent CN202211251843.X uses secondary distillation and membrane permeation synergistic technology to separate and purify crude disilane to prepare high-purity electronic-grade products, that is, firstly, secondary distillation technology is used to separate and purify crude disilane, and most of the components in the crude disilane except for complex systems such as near-boiling (the boiling point temperature difference generally does not exceed 2°C) or azeotropic systems are removed, thereby reducing the types and contents of impurity components in the crude disilane, and then membrane permeation separation is used to deeply remove the remaining impurities, thereby preparing electronic-grade disilane with higher purity; since most of the impurities in the crude disilane are first removed by distillation, the types and contents of impurity components in the subsequent adsorption process are reduced, the difficulty of adapting and developing adsorption materials is reduced, and the adsorption separation effect is improved; at the same time, the adsorption material is used to adsorb and separate the distillation product, and the distillation separation does not need to separate complex components such as near-boiling or azeotropic systems, thereby reducing the difficulty, load and energy consumption of distillation separation. However, the distillation conditions are not precisely controlled, the separation and purification effects are poor, the types and contents of impurity components after distillation separation are still high, the types and contents of impurity components treated by adsorption are still many, and the second-stage adsorption uses a single adsorption material, which cannot target the adsorption of different impurity components, and the separation and removal effects are poor; and the crude disilane is separated and purified by a synergistic method of membrane permeation and distillation. The membrane permeation operation has high pressure, harsh conditions, high energy consumption, and different components have different permeation dynamics. It is difficult to remove all impurity components using a single membrane.

[0010] For example, patents such as CN202310366991.4, CN202210770174.0, CN202311128024.0 and CN201810903987.6 use distillation and adsorption synergistic separation and purification technology to treat crude disilane to prepare electronic-grade products. This can achieve efficient separation and purification of crude disilane and prepare high-purity electronic-grade products, but precise distillation has not yet been achieved. After distillation, the types and contents of impurity components are still relatively large. A single adsorption material is still used for adsorption, and targeted adsorption cannot be achieved, and impurity removal is not thorough.

[0011] Therefore, it is of great significance to overcome the defects of the prior art to achieve efficient separation and purification of crude disilane and thus prepare high-purity electronic-grade products. Summary of the invention

[0012] In view of the above problems, the present application provides a method and apparatus for preparing electronic-grade disilane, which overcomes the defects of the prior art and prepares high-purity electronic-grade disilane products.

[0013] In order to achieve the above objectives, this application provides the following technical solutions:

[0014] On the one hand, the present invention provides a method for preparing electronic grade disilane (see Figure 1 ), the method mainly uses multi-stage low-temperature precision distillation and targeted adsorption synergistic separation and purification technology to separate and purify the crude disilane, that is, firstly use the multi-stage low-temperature precision distillation technology to completely or mostly remove the impurity components in the crude disilane except for the impurity components with complex systems such as near-boiling or azeotropic systems, so as to effectively reduce the types and contents of the impurity components in the crude disilane, and then use targeted adsorption distillation to separate and remove the remaining impurity components, so as to completely remove them and prepare high-purity electronic grade disilane products.

[0015] Among them, the multi-stage low-temperature precision distillation is realized by appropriately increasing the distillation temperature through methods such as pressurization to make the process conditions such as pressure and temperature become milder and precisely controllable, and by using high-precision equipment, instruments and nonlinear control theory to accurately control the operating conditions.

[0016] The multi-stage distillation includes both light removal distillation and heavy removal distillation. The light removal distillation may be performed first and then the heavy removal distillation, or the heavy removal distillation may be performed first and then the light removal distillation. Preferably, the light removal distillation is performed first and then the heavy removal distillation.

[0017] The light removal distillation can be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred.

[0018] The de-weighting distillation may be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred.

[0019] The precision control of the multi-stage low-temperature precision distillation is achieved through two aspects, namely:

[0020] A. By changing the distillation pressure and other conditions to increase the distillation temperature, the harsh process conditions during the ultra-low temperature distillation of disilane are reduced, so that the disilane distillation conditions become milder relative to the temperature, and the dependence on harsh ultra-low temperature utilities such as liquid nitrogen cooling is eliminated. Instead, milder utilities such as Freon, ethylene glycol, and even water cooling are used, so that the disilane distillation process conditions are easy to operate under more conventional conditions, and the operability and accuracy of the operation are improved. The distillation temperature can be increased to the atmospheric boiling point of disilane, zero degrees Celsius, or higher, preferably between the atmospheric boiling point of disilane and zero degrees Celsius.

[0021] B. The mild change in relative temperature of the distillation process enables the use of high-precision equipment and instrumentation that can be used under milder conditions, improving the accuracy of operations.

[0022] C. Use measurement and control systems that use advanced nonlinear control theory rather than linear control theory to improve the real-time performance and sensitivity of distillation equipment and instrumentation, and improve the accuracy of operations.

[0023] Targeted adsorption is achieved by using a combination of different types of specialized adsorption materials suitable for adsorbing different impurity components to achieve precise adsorption of different impurity components.

[0024] The adsorption material may be activated carbon or molecular sieve, or silica gel or other porous medium materials, preferably molecular sieve.

[0025] The method for preparing electronic grade disilane of the present invention mainly includes two parts, namely: multi-stage low temperature precision distillation and targeted adsorption, which are as follows:

[0026] A. Multi-stage cryogenic precision distillation

[0027] The crude disilane product (sub) with a certain flow rate (i.e., light feedstock) is introduced into the multi-stage distillation system (I) through the feed inlet (I1-1) of the light component removal distillation column (I1) of the multi-stage distillation system (I) for distillation separation. First, light component removal distillation is carried out in the light component removal distillation column (I1). The pressure at the top of the light component removal distillation column (I1) (abbreviated as light top pressure) is adjusted to a positive pressure, so that the light component removal distillation is pressurized distillation, and the temperature at the top of the light component removal distillation column (abbreviated as light top temperature) is higher than the boiling point temperature of disilane under normal pressure. Under this distillation condition, relatively mild heating and refrigeration media such as Freon and other utilities are used, and high-precision flow measurement and control elements, temperature measurement and control elements, pressure measurement and control elements and other equipment and instrumentation are used. At the same time, the above-mentioned equipment and instruments are precisely controlled by using the non-linear control theory logic module (I3) to achieve precise control of parameters such as the feed flow rate of the light component removal distillation column (abbreviated as light feedstock), the heating medium flow rate of the light component removal distillation column (light heat quantity), the cooling medium flow rate of the light component removal distillation column (light cooling capacity), the temperature at the top of the light component removal distillation column (light top temperature), the pressure at the top of the light component removal distillation column (light top pressure), the temperature at the bottom of the light component removal distillation column (abbreviated as light bottom temperature), the pressure at the bottom of the light component removal distillation column (abbreviated as light bottom pressure), the reflux flow rate of the light component removal distillation column (abbreviated as light reflux), the product flow rate at the top of the light component removal distillation column (abbreviated as light top quantity), and the product flow rate at the bottom of the light component removal distillation column (abbreviated as light bottom quantity).

[0028] Under the precise control of the light component removal distillation operation parameters, the crude disilane product (sub) entering the light component removal distillation column (I1) enters the bottom of the column and is vaporized by being heated by a high-temperature light component removal distillation column heating medium (noon1) with a certain flow rate (light heat quantity) introduced through the heat inlet (I1-2) of the light component removal distillation column (I1). The impurity components with boiling points lower than that of disilane gradually move towards the top of the light component removal distillation column (I1), while disilane and the heavy components with boiling points higher than that of disilane remain in the bottom of the light component removal distillation column (I1), separating the crude disilane product (sub). The temperature of the high-temperature light component removal distillation column heating medium (noon1) after heat exchange decreases and becomes a low-temperature light component removal distillation column heating medium (noon2), which is discharged through the heat outlet (I1-3) of the light component removal distillation column (I1) and recycled after treatment.

[0029] Impurity components with boiling points lower than that of disilane flow upward to the upper part of the light component removal rectification column (One 1) and are discharged from the top of the light component removal rectification column (One 1) in gaseous form. They are cooled into liquid state by the low-temperature light component removal rectification column cooling medium (Wei 1) with a certain flow rate (light cooling capacity) introduced through the cold inlet (One 1-5) of the light component removal rectification column (One 1). After being cooled into liquid state, a part of it flows back to the top of the dehydrogenation rectification column (One 1), and the remaining part is discharged from the light outlet (1-7) at the top of the light component removal rectification column (One 1) in the form of light components of the light component removal rectification (Chou) with a certain flow rate (light top flow rate) and sent to the impurity component treatment system for centralized treatment. Components with boiling points lower than that of disilane in the crude disilane (Zi), except for complex physical properties such as near-boiling or azeotropic, are completely separated and removed. The low-temperature light component removal rectification column cooling medium (Wei 1) after heat exchange is heated and becomes the high-temperature light component removal rectification column cold flow medium (Wei 2) and is discharged from the cold outlet (One 1-6) of the light component removal rectification column (One 1), and is recycled after treatment.

[0030] The disilane and components with boiling points higher than that of disilane remaining in the bottom of the light component removal rectification column (One 1) are discharged from the heavy outlet (One 1-4) at the bottom of the light component removal rectification column (One 1) in the form of heavy components of the light component removal rectification (Yin) with a certain flow rate (heavy bottom flow rate).

[0031] The heavy components of the light component removal rectification (Yin) discharged from the bottom of the light component removal rectification column (One 1) enter the heavy component removal rectification column (One 2) through the feed inlet (One 2-1) of the heavy component removal rectification column (One 2) with a certain flow rate (i.e., heavy feed) for heavy component removal rectification. The pressure at the top of the light component removal rectification column (One 1) (abbreviated as heavy top pressure) is adjusted to be a positive pressure, so that the heavy component removal rectification is pressurized rectification, and the temperature at the top of the heavy component removal rectification column (abbreviated as heavy top temperature) is higher than the boiling point temperature of disilane under normal pressure. Under such rectification conditions, common utilities such as relatively mild heating and refrigeration media such as Freon are used, and equipment and instruments such as high-precision flow measurement and control elements, temperature measurement and control elements, and pressure measurement and control elements are used. At the same time, the above-mentioned equipment and instruments are precisely controlled by using the nonlinear control theory logic module to achieve precise control of parameters such as the feed flow rate of the heavy component removal rectification column (abbreviated as heavy feed), the heating medium flow rate of the heavy component removal rectification column (heavy heat quantity), the cooling medium flow rate of the heavy component removal rectification column (abbreviated as heavy cooling capacity), the temperature at the top of the heavy component removal rectification column (abbreviated as heavy top temperature), the pressure at the top of the heavy component removal rectification column (abbreviated as heavy top pressure), the temperature at the bottom of the heavy component removal rectification column (abbreviated as heavy bottom temperature), the pressure at the bottom of the heavy component removal rectification column (abbreviated as heavy bottom pressure), the reflux flow rate of the heavy component removal rectification column (abbreviated as heavy reflux), the product flow rate at the top of the heavy component removal rectification column (abbreviated as heavy top flow rate), and the product flow rate at the bottom of the heavy component removal rectification column (abbreviated as heavy bottom flow rate).

[0032] Under the precise control of the stripping rectification operation parameters, the heavy component (yin) of the light stripping rectification enters the bottom of the stripping rectification column (Yi 2) and is heated and vaporized by the high-temperature stripping rectification column heating medium (Shen 1) with a certain flow rate (heavy heat quantity) introduced from the heat inlet (Yi 2-2) of the stripping rectification column (Yi 2). The disilane gradually moves towards the top of the light stripping rectification column (Yi 1), while the heavy components with boiling points higher than that of disilane remain in the bottom of the stripping rectification column (Yi 2), separating the heavy component (yin) of the light stripping rectification. The temperature of the high-temperature stripping rectification column heating medium (Shen 1) decreases after heat exchange and becomes the low-temperature stripping rectification column heating medium (Shen 2), which is discharged through the heat outlet (Yi 2-3) of the stripping rectification column (Yi 2) and recycled after treatment.

[0033] The components with boiling points higher than that of disilane remaining in the bottom of the stripping rectification column (Yi 2), except for the components with complex physical properties such as near-boiling or azeotropic components and trace impurity components such as metal ions, are completely separated and removed, and are discharged from the bottom heavy outlet (Yi 2-4) of the stripping rectification column (Yi 2) in the form of the heavy component (mao) of the stripping rectification with a certain flow rate (heavy bottom quantity), and sent to the impurity component treatment system for centralized treatment.

[0034] The components mainly composed of disilane flow upward in the stripping rectification column (Yi 2) and are discharged from the top of the stripping rectification column (Yi 2) in the form of gas, and are cooled into liquid by the low-temperature stripping rectification column cooling medium (You 1) with a certain flow rate (heavy cooling quantity) introduced through the cold inlet (Yi 2-5) of the stripping rectification column (Yi 2). After being cooled into liquid, a part of it flows back to the top of the stripping rectification column (Yi 2), and the remaining part is discharged from the top light outlet (Yi 2-7) of the stripping rectification column (Yi 2) in the form of the light component (chen) of the stripping rectification with a certain flow rate (heavy top quantity), thereby completely separating and removing the components with boiling points lower than that of disilane in the crude disilane (zi) except for the components with complex physical properties such as near-boiling or azeotropic components. The temperature of the low-temperature stripping rectification column cooling medium (You 1) rises after heat exchange and becomes the high-temperature stripping rectification column cold flow medium (You 2), which is discharged from the cold outlet (Yi 2-6) of the stripping rectification column (Yi 2) and recycled after treatment.

[0035] Through multi-stage low-temperature precision rectification, the precision rectification separation of each impurity component in the crude disilane is realized, completely removing the impurity components with complex physical properties such as near-boiling or azeotropic components, greatly reducing the types and contents of impurity components in the crude disilane, and increasing the content of the main component disilane in the crude disilane; at the same time, due to the subsequent adsorption separation treatment, in this multi-stage low-temperature precision rectification separation process, it is not necessary to remove the impurity components with complex physical properties such as near-boiling or azeotropic components and trace impurity components such as metal ions with very low contents and great removal difficulties, and the load of the multi-stage low-temperature precision rectification is small and the energy consumption is low.

[0036] B. Targeted adsorption

[0037] The light components (Chen) discharged from the bottom of the heavy component removal rectification column (Yi 2) are introduced into the adsorption system (Er) equipped with different adsorption materials through the feed inlet (Er 2-1) of the adsorption system (Er) for adsorption separation. The impurity components with complex physical properties such as near-boiling or azeotropic residues and trace impurity components such as metal ions in the light components (Chen) of the heavy component removal rectification are adsorbed and separated by different special adsorption materials and removed respectively, so as to prepare high-purity electronic-grade disilane (Si), and the removed impurities (Xu) are discharged for centralized treatment after being discharged.

[0038] Due to the targeted adsorption of the residual components in the crude disilane by special adsorption materials suitable for different impurity components, each impurity component is completely removed.

[0039] On the other hand, the present invention provides a device for realizing the preparation method of electronic-grade disilane (see Figure 2 ), which mainly includes a multi-stage low-temperature precision rectification system (Yi) and a targeted adsorption system (Er).

[0040] The multi-stage low-temperature precision rectification system is mainly used for precision rectification separation of crude disilane, removing most of the other impurity components except for the impurity components with complex physical properties such as near-boiling or azeotropic residues and trace impurity components such as metal ions, reducing the types and contents of impurity components in the crude disilane, and mainly includes a light component removal rectification column (Yi 1), a heavy component removal rectification column (Yi 2) and a non-linear control theory logic module (Yi 3).

[0041] The light component removal rectification column (Yi 1) is mainly used for removing the light components composed of impurity components with boiling points lower than that of disilane. Its feed inlet (Yi 1-1) is connected to the crude disilane supply system, the heat inlet (Yi 1-2) is connected to the heating medium system for the light component removal rectification column, the heat outlet (Yi 1-3) is connected to the heating medium system for the light component removal rectification column, the heavy outlet (Yi 1-4) is connected to the feed inlet (Yi 2-1) of the heavy component removal rectification column (Yi 2), the cold inlet (Yi 1-5) is connected to the cooling medium system for the light component removal rectification column, the cold outlet (Yi 1-6) is connected to the cooling medium system for the light component removal rectification column, and the light outlet (Yi 1-7) is connected to the impurity component treatment system; the measuring and controlling elements of parameters such as light feed, light heat, light cold, light top temperature, light top pressure, light kettle temperature, light kettle pressure, light reflux, light top quantity, and light bottom quantity installed on it are all high-precision equipment and instruments, and are connected to the non-linear control theory logic module (Yi 3) and precisely controlled by it.

[0042] Among them, the light component removal rectification column (Yi 1) can be a single-stage rectification column, or a multi-stage rectification column with two or more stages, preferably a single-stage rectification column; it can be a packed column, a plate column, or a composite column of packing and trays, preferably a packed column.

[0043] The described heavy component removal rectification column (One 2) is mainly used to remove the heavy components composed of impurity components with boiling points higher than that of disilane. Its feed inlet (One 2-1) is connected to the heavy component outlet (One 1-4) of the light component removal rectification column (One 1). The heat inlet (One 2-2) is connected to the heating medium system for the heavy component removal rectification column. The heat outlet (One 2-3) is connected to the heating medium system for the heavy component removal rectification column. The heavy component outlet (One 2-4) is connected to the impurity component treatment system. The cold inlet (One 2-5) is connected to the cooling medium system for the heavy component removal rectification column. The cold outlet (One 2-6) is connected to the cooling medium system for the heavy component removal rectification column. The light component outlet (One 2-7) is connected to the targeted adsorption system (Two); the measuring and controlling elements for parameters such as heavy feed, heavy heat, heavy cold, heavy top temperature, heavy top pressure, heavy kettle temperature, heavy kettle pressure, heavy reflux, heavy top flow rate, heavy bottom flow rate, etc. installed on it are all high-precision equipment and instruments, and are connected to the non-linear control theory logic module (One 3) and precisely controlled by it.

[0044] Among them, the heavy component removal rectification column (One 2) can be a single-stage rectification column, or a multi-stage rectification column of two stages or more, preferably a single-stage rectification column; it can be a packed column, a plate column, or a composite column of packing and trays, preferably a packed column.

[0045] The non-linear control theory logic module (One 3) controls the high-precision measuring and controlling elements installed on the light component removal rectification column (One 1) and the heavy component removal rectification column (One 2) in a non-linear theory manner, realizes the high-precision analysis, detection and control of these measuring and controlling elements, and is connected to and controls the measuring and controlling elements for parameters such as light feed, light heat, light cold, light top temperature, light top pressure, light kettle temperature, light kettle pressure, light reflux, light top flow rate, light bottom flow rate, heavy feed, heavy heat, heavy cold, heavy top temperature, heavy top pressure, heavy kettle temperature, heavy kettle pressure, heavy reflux, heavy top flow rate, heavy bottom flow rate, etc. on the light component removal rectification column (One 1) and the heavy component removal rectification column (One 2).

[0046] The targeted adsorption system (Two) is mainly used to further directionally separate and purify the crude disilane after multi-stage low-temperature precision rectification separation and purification, and deeply remove the impurities in the crude disilane to prepare high-purity electronic-grade disilane. Its feed inlet (Two 1-1) is connected to the light component outlet (One 1-1) of the heavy component removal rectification column (One 1) of the multi-stage low-temperature precision rectification system (One). The disilane outlet (Two 1-2) is connected to the disilane product storage system. The impurity outlet (1-3) is connected to the impurity treatment system.

[0047] Among them, the targeted adsorption system is composed of special adsorption materials suitable for adsorbing different impurity components. The special adsorption materials have a specific targeted adsorption function for one or several types of impurity components, but have a weaker or no adsorption function for other components. The type of special adsorption materials is determined according to the type and quantity of impurities in the crude disilane product, and various adsorption materials are loaded in the corresponding equipment. Among them, E1 is a device for loading special adsorption material 1 (E1), E2 is a device for loading special adsorption material 2 (E2), E3 is a device for loading special adsorption material 3 (E3), and En is a device for loading special adsorption material n (En, n is the number of adsorption materials, which varies according to the number of adsorption materials).

[0048] The outstanding technical effects of the present invention are:

[0049] The present invention adopts multi-stage cryogenic precision distillation and targeted adsorption synergistic separation and purification technology to separate and purify crude disilane to prepare high-purity electronic grade disilane. Multi-stage cryogenic precision distillation can realize the precise distillation of crude disilane, with good separation effect, and completely remove the components in the crude disilane except for impurity components with complex physical properties such as near boiling or azeotropic and trace impurity components such as metal ions, effectively reducing the types and contents of impurities required for subsequent adsorption separation; at the same time, due to the subsequent adsorption separation treatment, in the multi-stage cryogenic precision distillation separation process, it is not necessary to remove impurity components with complex physical properties such as near boiling or azeotropic and trace impurities such as metal ions with very low content and great difficulty in removal, effectively reducing the load and energy consumption of multi-stage cryogenic precision distillation.

[0050] By using targeted adsorption, special adsorption materials suitable for different impurity components can be used to carry out targeted adsorption separation and complete removal of the corresponding impurity components. The separation and removal effect is good, and high-purity electronic grade disilane can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a process flow chart of a method for preparing electronic grade disilane;

[0052] Figure 2 is a schematic diagram of an apparatus for preparing electronic grade disilane;

[0053] Figure 3 is a schematic diagram of the device of Example 1;

[0054] Figure 4 is a process flow chart of Example 1;

[0055] Figure 5 is a schematic diagram of the device of Example 2;

[0056] Figure 6 It is the process flow chart of Example 2;

[0057] Reference numerals:

[0058] I. Multi-stage low-temperature precision rectification system; I1. Light component removal rectification column; I1-1. Feed inlet of the light component removal rectification column; I1-2. Heat inlet of the light component removal rectification column; I1-3. Heat outlet of the light component removal rectification column; I1-4. Heavy component outlet of the light component removal rectification column; I1-5. Cold inlet of the light component removal rectification column; I1-6. Cold outlet of the light component removal rectification column; I1-7. Light component outlet of the light component removal rectification column; Light feed, feed flow rate of the light component removal rectification column; Light heat, heating medium flow rate of the light component removal rectification column; Light cold, cooling medium flow rate of the light component removal rectification column; Light top temperature, top temperature of the light component removal rectification column; Light top pressure, top pressure of the light component removal rectification column; Light kettle temperature, kettle temperature of the light component removal rectification column; Light kettle pressure, kettle pressure of the light component removal rectification column; Light reflux, reflux flow rate of the light component removal rectification column; Light top flow, top product flow rate of the light component removal rectification column; Light bottom flow, bottom product flow rate of the light component removal rectification column; I2. Heavy component removal rectification column; I2-1. Feed inlet of the heavy component removal rectification column; I2-2. Heat inlet of the heavy component removal rectification column; I2-3. Heat outlet of the heavy component removal rectification column; I2-4. Heavy component outlet of the heavy component removal rectification column; I2-5. Cold inlet of the heavy component removal rectification column; I2-6. Cold outlet of the heavy component removal rectification column; I2-7. Heavy component outlet of the heavy component removal rectification column; Heavy feed, feed flow rate of the heavy component removal rectification column; Heavy heat, heating medium flow rate of the heavy component removal rectification column; Heavy cold, cooling medium flow rate of the heavy component removal rectification column; Heavy top temperature, top temperature of the heavy component removal rectification column; Heavy top pressure, top pressure of the heavy component removal rectification column; Heavy kettle temperature, kettle temperature of the heavy component removal rectification column; Heavy kettle pressure, kettle pressure of the heavy component removal rectification column; Heavy reflux, reflux flow rate of the heavy component removal rectification column; Heavy top flow, top product flow rate of the heavy component removal rectification column; Heavy bottom flow, bottom product flow rate of the heavy component removal rectification column; I3. Nonlinear control theory logic module; 2. Heavy component removal column; II. Targeted adsorption system; II1. Equipment filled with adsorption material 1; II2. Equipment filled with adsorption material 2; II3. Equipment filled with adsorption material 3; IIn. Equipment filled with adsorption material n; II1-1. Feed inlet of the targeted adsorption system; II1-2. Outlet of disilane of the targeted adsorption system; II1-3. Outlet of impurities of the targeted adsorption system.

[0059] a. Crude disilane; b. Light components of the light component removal rectification column; c. Heavy components of the light component removal rectification column; d. Heavy components of the heavy component removal rectification column; e. Light components of the heavy component removal rectification column; f. Electronic grade disilane product; g1. Heating medium for the high-temperature light component removal rectification column; g2. Heating medium for the low-temperature light component removal rectification column; h1. Cooling medium for the low-temperature light component removal rectification column; h2. Cooling medium for the high-temperature light component removal rectification column; i1. Heating medium for the high-temperature heavy component removal rectification column; i2. Heating medium for the low-temperature heavy component removal rectification column; j1. Cooling medium for the low-temperature heavy component removal rectification column; j2. Cooling medium for the high-temperature heavy component removal rectification column; k1. Special adsorption material 1; k2. Special adsorption material 2; k3. Special adsorption material 3; kn. Special adsorption material n. Specific embodiments

[0060] Next, in combination with the embodiments of the present invention, the technical solutions of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments prepared by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0061] The technical solutions and effects of the present invention will be described in combination with specific examples and comparative examples. Specific Example 1

[0063] This example will be described in detail for the separation and purification of crude disilane to prepare electronic-grade disilane by the traditional multi-stage cryogenic distillation and adsorption synergistic separation technology.

[0064] The physical properties of the crude disilane raw material used are shown in Table 1. Among them, dichloromethane is an azeotrope of disilane (the boiling point difference is 0.4 °C), and trisilane and tetrasilane are homologues of disilane, containing a large amount of impurity components such as metal ions that are difficult to separate.

[0065] Among them, the multi-stage cryogenic distillation includes low-temperature light component distillation and low-temperature heavy component distillation, both of which are atmospheric pressure low-temperature distillation; the adsorption material is 3A molecular sieve that has a good adsorption effect on dichloromethane and a certain adsorption capacity for other impurities.

[0066] Table 1 Physical Property Composition of Crude Disilane

[0067]

[0068]

[0069] The device used in this example is shown in Figure 3 , mainly including a multi-stage distillation system (I) and an adsorption system (II).

[0070] The multi-stage cryogenic distillation system is a two-stage distillation, mainly including a light component distillation column (I1) and a heavy component distillation column (I2).

[0071] The light component distillation column (I1) is mainly used to remove the light components composed of impurity components with boiling points lower than that of disilane. It is a single-stage plate distillation column with 30 theoretical plates. Its feed port (I1-1) is connected to the crude disilane supply system, the heat inlet (I1-2) is connected to the heating medium system for the light component distillation column, the heat outlet (I1-3) is connected to the heating medium system for the light component distillation column, the heavy outlet (I1-4) is connected to the feed port (I2-1) of the heavy component distillation column (I2), the cold inlet (I1-5) is connected to the cooling medium system for the light component distillation column, the cold outlet (I1-6) is connected to the cooling medium system for the light component distillation column, and the light outlet (I1-7) is connected to the impurity component treatment system.

[0072] Among them, the light component removal rectification is carried out under atmospheric pressure rectification, that is, the light top pressure is 101.2 KPa, and the crude disilane contains a large amount of low-boiling substances such as low hydrogen, nitrogen, oxygen, methane, etc. The light top temperature is -70 °C, and the light bottom temperature is -60 °C. Therefore, the heating medium of the light component removal rectification column is Freon R22 (boiling point: -38 °C, melting point: -146 °C), and the cooling medium of the light component removal rectification column is liquid nitrogen (boiling point: -196 °C, melting point: -210 °C). The light component removal rectification column and its utility engineering are in an extremely low temperature state, with harsh physical properties, a large temperature difference from the external environment, and defects such as large cold radiation and difficult operation. The precise operation and operation are difficult; at the same time, the measurement and control elements of parameters such as light feed, light heat, light cooling, light top temperature, light top pressure, light bottom temperature, light bottom pressure, light reflux, light top quantity, and light bottom quantity installed on it must use equipment and instruments that can withstand extremely low temperature conditions. The temperature measurement elements such as light top temperature and light bottom temperature use K-type thermocouples with a wide temperature measurement range (measurement range: -200 to 2200 °C), and the pressure measurement elements such as light top pressure and light bottom pressure use low-temperature stainless steel materials that are resistant to low-temperature brittleness but have weak sensitivity. The light feed, light heat, light cooling, light reflux, light top quantity of light component removal, light bottom quantity, etc. use mechanical flow measurement elements that are resistant to low temperature but have low sensitivity. The measurement and control logic modules used adopt linear control theory. Therefore, the accuracy of the temperature measurement and control elements is ±2 °C, the accuracy of the pressure measurement and control elements is ±50 Pa, and the accuracy of the flow measurement and control elements is ±0.01 kg / h.

[0073] The described heavy component removal rectification column (One 2) is mainly used to remove the heavy components composed of impurity components with boiling points higher than that of disilane. It is a single-stage plate rectification column with 40 theoretical plates. Its feed port (One 2-1) is connected to the heavy outlet (One 1-4) of the light component removal rectification column (One 1), the heat inlet (One 2-2) is connected to the heating medium system for the heavy component removal rectification column, the heat outlet (One 2-3) is connected to the heating medium system for the heavy component removal rectification column, the heavy outlet (One 2-4) is connected to the impurity component treatment system, the cold inlet (One 2-5) is connected to the cooling medium system for the heavy component removal rectification column, the cold outlet (One 2-6) is connected to the cooling medium system for the heavy component removal rectification column, and the light outlet (One 2-7) is connected to the targeted adsorption system (Two).

[0074] Among them, the heavy component removal rectification adopts atmospheric rectification, that is, the heavy top pressure is 101.2 KPa, the heavy top temperature is -15 °C, and the heavy kettle temperature is -5 °C. Therefore, the heating medium of the heavy component removal rectification column is R11 (boiling point: 23.8 °C, melting point: -111 °C), the cooling medium of the light component removal rectification column is Freon R11. The heavy component removal rectification column and its utility engineering are in a lower temperature state, with more demanding physical properties, a large temperature difference from the external environment, and defects such as large cold radiation and difficult operation, making precise operation difficult. The measuring and controlling elements for parameters such as heavy feed, heavy heat, heavy cold, heavy top temperature, heavy top pressure, heavy kettle temperature, heavy kettle pressure, heavy reflux, heavy top flow, and heavy bottom flow installed on it must be equipment and instruments that can withstand lower temperature conditions. The temperature measuring elements such as heavy top temperature and heavy kettle temperature use PT100 thermal resistors with a larger temperature measurement range (range: -100 to 800 °C), the pressure measuring elements such as heavy top pressure and heavy kettle pressure use materials that are resistant to lower temperature brittleness but have weaker sensitivity, and the differential pressure type flow measuring elements for heavy feed, heavy heat, heavy cold, heavy reflux, heavy top flow, and heavy bottom flow use materials that are resistant to lower temperature but have lower sensitivity. The basic measuring and controlling logic modules used adopt linear theory and are difficult to perform non-linear responses to real-time parameter changes. Therefore, the accuracy of the temperature measuring and controlling elements is ±0.8 °C, the accuracy of the pressure measuring and controlling elements is ±10 Pa, and the accuracy of the flow measuring and controlling elements is ±0.005 kg / h.

[0075] The adsorption system (II) is mainly used to further separate and purify the crude disilane product after multi-stage low-temperature rectification separation and purification, deeply remove impurities in the crude disilane product to prepare high-purity electronic-grade disilane. The adsorption material (Hai 1) used is 3A molecular sieve, which is filled in the adsorption equipment (II 1). Its feed port (II 1-1) is connected to the light outlet (I 1-1) of the heavy component removal rectification column (I 1) of the multi-stage low-temperature precision rectification system (I), the disilane outlet (II 1-2) is connected to the disilane product storage system, and the impurity outlet (1-3) is connected to the impurity treatment system.

[0076] The process of separating and purifying crude disilane to prepare electronic-grade products is as follows:

[0077] A. Multi-stage low-temperature rectification

[0078] The saturated liquid crude disilane product (Zi) with a light feed of 1 kg / h, a temperature of -40 °C, and a pressure of 2 MPa is introduced into the multi-stage rectification system (I) through the feed port (I 1-1) of the light component removal rectification column (I 1) of the multi-stage rectification system (I) for rectification separation. First, light component removal rectification is carried out in the light component removal rectification column (I 1), and the light top pressure is adjusted to 101.2 Kpa(A) to make the light component removal rectification an atmospheric rectification, and the light top temperature is made -70 °C.

[0079] The crude disilane product (son) entering the light component removal distillation column (No. 1) enters the bottom of the column and is vaporized by heating with a high-temperature light component removal distillation column heating medium [Wu 1, Freon R22 (saturated vapor)] with a light heat quantity of 3.7 kg / h and a temperature of -20 °C introduced through the heat inlet (No. 1-2) of the light component removal distillation column (No. 1). The impurity components with boiling points lower than that of disilane gradually move towards the top of the light component removal distillation column (No. 1), while disilane and the heavy components with boiling points higher than that of disilane remain in the bottom of the light component removal distillation column (No. 1), separating the crude disilane product (son). The temperature of the Freon R22 saturated vapor (Wu 1) after heat exchange decreases and becomes a low-temperature light component removal distillation column heating medium [Wu 2, Freon R22 (saturated liquid)] with a temperature of -39 °C and is discharged through the heat outlet (No. 1-3) of the light component removal distillation column (No. 1), and is recycled after treatment. During the entire heating process, calculated based on the unit of crude disilane product processed, the heat consumption for vaporization is 860 kcal / kg (crude disilane product).

[0080] The impurity components with boiling points lower than that of disilane flow towards the upper part of the light component removal distillation column (No. 1) and are discharged from the top of the light component removal distillation column (No. 1) in the form of gas, and are cooled into liquid by a low-temperature light component removal distillation column cooling medium (Wei 1, liquid nitrogen in liquid state) with a light cooling quantity of 36 kg / h and a temperature of -205 °C introduced through the cold inlet (No. 1-5) of the light component removal distillation column (No. 1). After being cooled into liquid, a part of it flows back to the top of the dehydrogenation distillation column (No. 1), and the remaining part is discharged from the light outlet at the top (1-7) of the light component removal distillation column (No. 1) in the form of light component removal light components (Chou) at a certain flow rate (light top quantity) and sent to the impurity component treatment system for centralized treatment. The components with boiling points lower than that of disilane in the crude disilane product (son) except for complex physical properties such as near-boiling or azeotropic are completely separated and removed. The temperature of the low-temperature light component removal distillation column cooling medium (Wei 1) after heat exchange rises and becomes a high-temperature light component removal distillation column cold flow medium (Wei 2, liquid nitrogen) with a temperature of -200 °C and is discharged through the cold outlet (No. 1-6) of the light component removal distillation column (No. 1), and is recycled after treatment. During the entire heating process, calculated based on the unit of crude disilane product processed, the cooling consumption of cold quantity is 860 kcal / kg (crude disilane product).

[0081] The disilane and the components with boiling points higher than that of disilane remaining in the bottom of the light component removal distillation column (No. 1) are discharged from the heavy outlet at the bottom (No. 1-4) of the light component removal distillation column (No. 1) in the form of light component removal heavy components (Yin) at a flow rate (light bottom quantity) of 0.4806 kg / h. The physical properties of the discharged light component removal heavy components (Yin) are shown in Table 2.

[0082] Table 2 Physical Property Composition of Light Component Removal Heavy Components (Yin)

[0083]

[0084] The heavy-light rectification column bottoms (yin) are discharged from the light-removing rectification column (Yi 1) and enter the heavy-removing rectification column (Yi 2) through the feed port (Yi 2-1) of the heavy-removing rectification column (Yi 2) at a certain flow rate (heavy feed) for heavy-removing rectification. The heavy top pressure is adjusted to 101.2 KPa to make the heavy-removing rectification an atmospheric rectification, and the heavy top temperature is -14 °C.

[0085] The heavy-light rectification column bottoms (yin) in the kettle of the heavy-removing rectification column (Yi 2) are heated and vaporized by the high-temperature heavy-removing rectification column heating medium [Shen 1, Freon R11 (saturated steam)] with a heavy heat input of 2.3 kg / h and a temperature of 30 °C introduced from the heat inlet (Yi 2-2) of the heavy-removing rectification column (Yi 2). Disilane gradually moves towards the top of the heavy-removing rectification column (Yi 1), while the heavy components with a boiling point higher than that of disilane remain in the kettle of the heavy-removing rectification column (Yi 2), thereby separating the heavy-light rectification column bottoms (yin). After heat exchange, the temperature of the high-temperature heavy-removing rectification column heating medium (Shen 1) decreases and becomes the low-temperature heavy-removing rectification column heating medium (Shen 2), which is discharged from the heat outlet (Yi 2-3) of the heavy-removing rectification column (Yi 2) and recycled after treatment. During the entire heating process, calculated based on the unit mass of crude disilane processed, the heat consumed for vaporization is 540 kcal / kg (crude disilane).

[0086] The components with a boiling point higher than that of disilane in the kettle of the heavy-removing rectification column (Yi 2), except for components with complex physical properties such as near-boiling or azeotropic components and trace impurity components such as metal ions, are completely separated and removed, and are discharged from the bottom heavy outlet (Yi 2-4) of the heavy-removing rectification column (Yi 2) in the form of heavy-removing rectification column bottoms (mao) at a certain flow rate (heavy bottom flow) and sent to the impurity component treatment system for centralized treatment.

[0087] The components mainly composed of disilane flow towards the upper part of the heavy-removing rectification column (Yi 2) and are discharged from the top of the heavy-removing rectification column (Yi 2) in gaseous form. They are cooled into a liquid state by the low-temperature heavy-removing rectification column cooling medium [You 1, Freon R11 (liquid)] with a heavy cold input of 22 kg / h and a temperature of -30 °C introduced through the cold inlet (Yi 2-5) of the heavy-removing rectification column (Yi 2). After being cooled into a liquid state, a part of it is refluxed to the top of the heavy-removing rectification column (Yi 2), and the remaining part is discharged from the top light outlet (Yi 2-7) of the heavy-removing rectification column (Yi 2) in the form of light components of the heavy-removing rectification column (chen) at a flow rate of 0.3747 kg / h. The physical properties of the light components of the heavy-removing rectification column (chen) are shown in Table 3, thereby completely separating and removing the components with a boiling point lower than that of disilane in the crude disilane (zi) except for components with complex physical properties such as near-boiling or azeotropic components. After heat exchange, the temperature of the low-temperature heavy-removing rectification column cooling medium (You 1) rises and becomes the high-temperature heavy-removing rectification column cold flow medium (You 2) with a temperature of -20 °C, which is discharged from the cold outlet (Yi 2-6) of the heavy-removing rectification column (Yi 2) and recycled after treatment. Calculated based on the unit mass of crude disilane processed, the cold consumed for cooling is 540 kcal / kg (crude disilane).

[0088] Table 3 Physical property composition of light components (Chen) in deweighting rectification

[0089]

[0090] Through multi-stage low-temperature rectification, the rectification separation of each impurity component in the crude disilane is realized, and the impurity components with complex physical properties such as near-boiling or azeotropic are completely removed, greatly reducing the types and contents of impurity components in the crude disilane and increasing the content of the main component disilane in the crude disilane. However, components with complex physical properties such as dichloromethane cannot be removed.

[0091] II. Adsorption

[0092] The light components (Chen) in deweighting rectification discharged from the bottom of the deweighting rectification column (One 2) are introduced into the adsorption system (Two) equipped with the adsorption material (Hai 1, 5A molecular sieve) through the feed port (Two 2-1) of the adsorption system (Two) for adsorption separation. The impurity components with complex physical properties such as near-boiling or azeotropic remaining in the light components (Chen) in deweighting rectification and trace impurity components such as metal ions are respectively targeted adsorbed by different adsorption materials and thus completely removed, thereby preparing electronic-grade disilane (Si). Its physical properties are shown in Table 4, and the removed impurities (Xu) are discharged and centrally treated.

[0093] As can be seen from Table 4, the purity of the electronic-grade product prepared by separating and purifying crude disilane through the traditional multi-stage low-temperature rectification and adsorption collaborative separation technology can reach 99.992 wt.% (4N2), and the other impurity components are generally between 1 and 10 ppm, basically meeting the quality requirements of 4N products, but cannot meet the product purity requirements of 4-5N or even above 5N.

[0094] Table 4 Physical property composition of electronic-grade disilane product

[0095]

[0096] As can be seen from Table 4, the purity of the electronic-grade product prepared by separating and purifying crude disilane through the traditional multi-stage low-temperature rectification and adsorption collaborative separation and purification technology can reach 99.992 wt.% (4N2), and the other impurity components are generally between 1 and 10 ppm, basically meeting the quality requirements of 4N products, but cannot meet the product purity requirements of 4-5N or even above 5N. When processing a unit mass of crude disilane and preparing the above-mentioned electronic-grade disilane product, the heat and cold consumption of the de-lighting rectification column are both 860 kcal / kg (crude disilane), and the heat and cold consumption of the deweighting rectification column are both 540 kcal / kg (crude disilane), and the total heat and cold consumption are both 1400 kcal / kg (crude disilane). Specific Example 2

[0098] This embodiment will be described in detail by using the multi-stage cryogenic precision distillation and targeted adsorption synergistic separation technology to separate and purify the crude disilane product to prepare an electronic-grade product.

[0099] Among them, the physical properties of the crude disilane used are shown in Table 1.

[0100] Among them, the multi-stage cryogenic precision distillation adopts pressurized two-stage cryogenic precision distillation, including cryogenic light component removal precision distillation and cryogenic heavy component removal precision distillation; the adsorption material is composed of 3A molecular sieve (Hai 1), 5A molecular sieve (Hai 2) and activated carbon (Hai 3) which have good adsorption effects on trace impurities such as dichloromethane, propylsilane, butylsilane and metal ions respectively.

[0101] The device used in this example is shown in Figure 3 , and mainly includes a multi-stage cryogenic precision distillation system (One) and a targeted adsorption system (Two).

[0102] The multi-stage cryogenic distillation system is a two-stage distillation, mainly including a light component removal distillation column (One 1) and a heavy component removal distillation column (One 2).

[0103] The light component removal distillation column (One 1) is mainly used to remove the light components composed of impurity components with boiling points lower than that of disilane. It is a single-stage packed distillation column with 30 theoretical plates. Its feed port (One 1-1) is connected to the crude disilane supply system, the heat inlet (One 1-2) is connected to the heating medium system for the light component removal distillation column, the heat outlet (One 1-3) is connected to the heating medium system for the light component removal distillation column, the heavy outlet (One 1-4) is connected to the feed port (One 2-1) of the heavy component removal distillation column (One 2), the cold inlet (One 1-5) is connected to the cooling medium system for the light component removal distillation column, the cold outlet (One 1-6) is connected to the cooling medium system for the light component removal distillation column, and the light outlet (One 1-7) is connected to the impurity component treatment system.

[0104] Among them, the light component removal rectification uses normal pressure or pressurized rectification, that is, the light top pressure is 2 MPa, the light top temperature is -10 °C, and the light bottom temperature is 0 °C. Therefore, the heating medium of the light component removal rectification column uses Freon R11, and the cooling medium of the light component removal rectification column uses ice brine (boiling point: 105 °C, melting point: -30 °C). The temperature of the light component removal rectification column and its utility engineering is mild, and it is not much different from the external environmental temperature. Defects such as large cold quantity radiation and difficult operation are overcome, and precise operation can be achieved. At the same time, the measuring and controlling elements of parameters such as light feed, light heat, light cold, light top temperature, light top pressure, light bottom temperature, light bottom pressure, light reflux, light top quantity, and light bottom quantity installed on it no longer use equipment and instruments that are resistant to extremely low temperature conditions, but use equipment and instruments that can operate under normal temperature or near-normal temperature conditions. The temperature measuring elements such as light top temperature and light bottom temperature use kerosene temperature measuring elements with a narrow temperature measuring range (range: -30 to 150 °C), the pressure measuring elements such as light top pressure and light bottom pressure use highly sensitive alloy materials, and the light feed, light heat, light cold, light reflux, light top quantity, light bottom quantity, etc. use high-sensitivity mass flow elements. The used measuring and controlling logic modules basically adopt non-linear theory to perform non-linear response to the real-time changes of parameters. The accuracy of the temperature measuring and controlling elements is ±0.2 °C, the accuracy of the pressure measuring and controlling elements is ±5 Pa, and the accuracy of the flow measuring and controlling elements is ±0.001 kg / h.

[0105] The described heavy component removal rectification column (One 2) is mainly used to remove heavy components composed of impurity components with boiling points higher than that of disilane. It is a single-stage plate rectification column with 40 theoretical plates. Its feed port (One 2-1) is connected to the heavy component outlet (One 1-4) of the light component removal rectification column (One 1), the heat inlet (One 2-2) is connected to the heating medium system for the heavy component removal rectification column, the heat outlet (One 2-3) is connected to the heating medium system for the heavy component removal rectification column, the heavy component outlet (One 2-4) is connected to the impurity component treatment system, the cold inlet (One 2-5) is connected to the cooling medium system for the heavy component removal rectification column, the cold outlet (One 2-6) is connected to the cooling medium system for the heavy component removal rectification column, and the light component outlet (One 2-7) is connected to the targeted adsorption system (Two).

[0106] Among them, the heavy component removal rectification adopts atmospheric rectification, that is, the heavy top pressure is 1.5 MPa, the heavy top temperature is -1 °C, and the heavy kettle temperature is 10 °C. Therefore, the heating medium of the heavy component removal rectification column is water (boiling point: 100 °C, melting point: 0 °C), and the cooling medium of the rectification column is an ethylene glycol aqueous solution (boiling point: 105 °C, melting point: -20 °C). The temperature of the light component removal rectification column and its utilities is mild, and it does not differ much from the external environmental temperature. Defects such as large cold quantity radiation and high operation difficulty are overcome, and precise operation can be achieved; the measuring and controlling elements of parameters no longer use equipment and instruments that are resistant to extremely low temperature conditions, but use equipment and instruments that can operate under normal temperature or near-normal temperature conditions. The temperature measuring elements such as the heavy top temperature and the heavy kettle temperature use kerosene temperature measuring elements with a narrow temperature measuring range (range: -30 to 150 °C), the pressure measuring elements such as the heavy top pressure and the middle kettle pressure use highly sensitive alloy materials, and the heavy feed, heavy heat, heavy cold quantity, heavy reflux, heavy light top quantity, heavy bottom quantity, etc. use highly sensitive mass flow elements. The used measuring and controlling logic modules basically adopt non-linear theory to perform non-linear responses to the real-time changes of parameters. The accuracy of the temperature measuring and controlling elements is ±0.2 °C, the accuracy of the pressure measuring and controlling elements is ±5 Pa, and the accuracy of the flow measuring and controlling elements is ±0.001 kg / h.

[0107] The targeted adsorption system (II) is mainly used to further directionally separate and purify the crude disilane after multi-stage low-temperature rectification separation and purification, and deeply remove impurities in the crude disilane to prepare high-purity electronic-grade disilane. The adsorption materials are composed of 3A molecular sieve (Hai 1), 5A molecular sieve (Hai 2) and activated carbon (Hai 3) which have good adsorption effects on trace impurities such as dichloromethane, trisilane, tetrasilane and metal ions respectively, and are filled in the adsorption equipment (II 1), adsorption equipment (II 2) and adsorption equipment (II 3) respectively. Its feed port (II 1-1) is connected to the light outlet (I 1-1) of the heavy component removal rectification column (I 1) of the multi-stage low-temperature precision rectification system (I), the disilane outlet (II 1-2) is connected to the disilane product storage system, and the impurity outlet (1-3) is connected to the impurity treatment system.

[0108] The process of separating and purifying crude disilane to prepare electronic-grade products is as follows:

[0109] A. Multi-stage low-temperature precision rectification

[0110] The saturated liquid crude disilane (son) with a light feed of 1 kg / h, a temperature of -40 °C and a pressure of 2 MPa is introduced into the multi-stage rectification system (I) through the feed port (I 1-1) of the light component removal rectification column (I 1) of the multi-stage rectification system (I) for rectification separation. First, light component removal rectification is carried out in the light component removal rectification column (I 1), and the light top pressure is adjusted to 2 MPa (A) to make the light component removal rectification an atmospheric rectification, and the light top temperature is -10 °C.

[0111] The crude disilane (substance) enters the light - removing rectifying column (No. 1) and is vaporized by the high - temperature light - removing rectifying column heating medium [Wu1, Freon R11 (saturated steam)] with a light heat quantity of 3.2 kg / h and a temperature of 25°C introduced through the heat inlet (No. 1 - 2) of the light - removing rectifying column (No. 1). The impurity components with boiling points lower than that of disilane gradually move towards the top of the light - removing rectifying column (No. 1), while disilane and the heavy components with boiling points higher than that of disilane remain in the kettle of the light - removing rectifying column (No. 1), thus separating the crude disilane (substance). After heat exchange, the saturated steam of Freon R11 (Wu1) reduces in temperature and becomes the low - temperature light - removing rectifying column heating medium [Wu2, Freon R11 (saturated liquid)] with a temperature of 23.8°C and is discharged through the heat outlet (No. 1 - 3) of the light - removing rectifying column (No. 1), and is recycled after treatment. During the whole heating process, calculated by the unit of crude disilane processed, the heat consumed for vaporization is 750 kcal / kg (crude disilane), which is lower than the heat consumed in traditional light - removing rectification, with a decrease of about 12.8%.

[0112] The impurity components with boiling points lower than that of disilane flow towards the upper part of the light - removing rectifying column (No. 1) and are discharged from the top of the light - removing rectifying column (No. 1) in gaseous form, and are cooled into liquid state by the low - temperature light - removing rectifying column cooling medium (Wei1, ice - brine) with a light cooling quantity of 31.4 kg / h and a temperature of - 20°C introduced through the cold inlet (No. 1 - 5) of the light - removing rectifying column (No. 1). After being cooled into liquid state, a part of it flows back to the top of the dehydrogenation rectifying column (No. 1), and the remaining part is discharged from the light outlet (1 - 7) at the top of the light - removing rectifying column in the form of light - removing rectifying light components (Chou) and sent to the impurity component treatment system for centralized treatment, so that the components with boiling points lower than that of disilane in the crude disilane (substance), except for complex physical properties such as near - boiling or azeotropic, are completely separated and removed. After heat exchange, the low - temperature light - removing rectifying column cooling medium (Wei1) increases in temperature and becomes the high - temperature light - removing rectifying column cold flow medium (Wei2, ice - brine) with a temperature of - 10°C and is discharged from the cold outlet (No. 1 - 6) of the light - removing rectifying column (No. 1), and is recycled after treatment. During the whole heating process, calculated by the unit of crude disilane processed, the cooling capacity consumed for cooling is 750 kcal / kg (crude disilane), which is lower than the cooling capacity consumed in traditional light - removing rectification, with a decrease of about 12.8%.

[0113] The disilane and the components with boiling points higher than that of disilane remaining in the kettle of the light - removing rectifying column (No. 1) are discharged from the heavy outlet (No. 1 - 4) at the bottom of the light - removing rectifying column in the form of light - removing rectifying heavy components (Yin) at a flow rate of 0.4805 kg / h (light bottom quantity). The physical properties of the discharged light - removing rectifying heavy components (Yin) are shown in Table 5. It can be seen from Table 5 that when using precise light - removing rectification to conduct light - removing treatment on crude disilane, each light - component impurity is removed more thoroughly.

[0114] Table 5 Physical Property Composition of Light - Removing Rectifying Heavy Components (Yin)

[0115]

[0116] The heavy components after light component removal from the light component removal distillation column (No. 1) (yin) enter the heavy component removal distillation column (No. 2) through the feed port (No. 2-1) of the heavy component removal distillation column (No. 2) at a certain flow rate (heavy feed) for heavy component removal distillation. The top pressure of the heavy component removal is adjusted to 1.5 MPa to make the heavy component removal distillation an atmospheric distillation, and the top temperature of the heavy component is -1 °C.

[0117] The heavy components after light component removal (yin) in the kettle of the heavy component removal distillation column (No. 2) are heated and vaporized by the high-temperature heavy component removal distillation column heating medium [Shen 1, water (saturated steam)] with a heavy heat input of 2.3 kg / h and a temperature of 120 °C introduced from the heat inlet (No. 2-2) of the heavy component removal distillation column (No. 2). Disilane gradually moves towards the top of the light component removal distillation column (No. 1), while the heavy components with a boiling point higher than that of disilane remain in the kettle of the heavy component removal distillation column (No. 2), separating the heavy components after light component removal (yin). The temperature of the high-temperature heavy component removal distillation column heating medium (Shen 1) after heat exchange drops to 100 °C and becomes the low-temperature heavy component removal distillation column heating medium (Shen 2), which is discharged through the heat outlet (No. 2-3) of the heavy component removal distillation column (No. 2) and recycled after treatment. During the whole heating process, calculated based on the unit mass of crude disilane processed, the heat consumption for vaporization is 480 kcal / kg (crude disilane), which is lower than that of the traditional heavy component removal distillation, decreasing by about 11.1%.

[0118] The components with a boiling point higher than that of disilane in the kettle of the heavy component removal distillation column (No. 2), except for the components with complex physical properties such as near-boiling or azeotropic components and trace impurity components such as metal ions, are completely separated and removed, and are discharged from the bottom heavy outlet (No. 2-4) of the heavy component removal distillation column (No. 2) in the form of heavy components after heavy component removal (mao), and sent to the impurity component treatment system for centralized treatment.

[0119] The component mainly composed of disilane flows upward to the upper part of the heavy component removal rectification column (One 2) and is discharged from the top of the heavy component removal rectification column (One 2) in the form of gas. It is cooled into a liquid state by the cooling medium [You 1, ethylene glycol aqueous solution] of the heavy component removal rectification column with a flow rate of 18.5 kg / h and a temperature of -10°C introduced through the cold inlet (One 2-5) of the heavy component removal rectification column (One 2). After being cooled into a liquid state, a part of it flows back to the top of the heavy component removal rectification column (One 2), and the remaining part is discharged from the light outlet (One 2-7) of the heavy component removal rectification column (One 2) in the form of the light component (Chen) of the heavy component removal rectification with a flow rate of 0.3733 kg / h. The physical property composition of the light component (Chen) of the heavy component removal rectification is shown in Table 6, so that the components with boiling points lower than that of disilane in the crude disilane (Zi) except for complex physical properties such as near-boiling or azeotropic are completely separated and removed. The cooled cooling medium (You 1) of the heavy component removal rectification column is heated up to become the hot flow medium (You 2) of the heavy component removal rectification column with a temperature of 0°C and is discharged from the cold outlet (One 2-6) of the heavy component removal rectification column (One 2), and is recycled after being processed. Calculated based on the unit of crude disilane processed, the cooling consumption is 480 kcal / kg (crude disilane), which is lower than the heat consumption of traditional heavy component removal rectification, and decreases by about 11.1%.

[0120] As can be seen from Table 5, when the crude disilane is subjected to heavy component removal treatment using precise heavy component removal rectification, each heavy component impurity is removed more thoroughly. In particular, the temperature accuracy can reach ±0.2°C, and precise control of the rectification temperature can be achieved. Under the operation of rectification with high temperature accuracy, the near-boiling substance dichloromethane can be separated and removed.

[0121] Table 6 Physical property composition of the light component (Chen) of the heavy component removal rectification

[0122]

[0123] Through multi-stage low-temperature precision rectification, the rectification separation of each impurity component in the crude disilane is realized, and the impurity components with complex physical properties such as near-boiling or azeotropic are completely removed, greatly reducing the types and contents of impurity components in the crude disilane. Even some components with complex physical properties such as dichloromethane that are difficult to remove can be partially removed, with more thorough removal and lower energy consumption required.

[0124] B. Targeted adsorption

[0125] The de-heavy distillation light component (C) discharged from the bottom of the de-heavy distillation tower (I-2) is introduced into the targeted adsorption system (II) filled with adsorption material through the feed port (II-2-1) of the adsorption system (II) for targeted adsorption separation. The de-heavy distillation light component (C) enters the adsorption device (II-1) and is targetedly adsorbed and removed by the adsorption material (H1, 3A molecular sieve) for dichloromethane impurity component therein. Then, it enters the adsorption device (II-2) and is targetedly adsorbed and removed by the adsorption material (H2, 5A molecular sieve) for propylene glycol impurity component therein. The impurity components such as silane and butadisilane finally enter the adsorption device (E3) and are targetedly adsorbed and removed by the adsorption material (H3, activated carbon) to remove trace impurity components such as monosilane and metal ions therein. The impurity components with complex physical properties such as near-boiling or azeotropic properties and trace impurity components such as metal ions remaining in the light component (C) after de-heavy distillation are respectively directed and adsorbed and completely removed through different adsorption materials to prepare electronic grade disilane (Si). Its physical properties are shown in Table 7. The removed impurities (Xu) are discharged and centrally treated.

[0126] It can be seen from Table 7 that the purity of the electronic-grade product prepared by separating and purifying crude disilane through traditional multi-stage cryogenic distillation and adsorption synergistic separation technology can reach 99.9992wt.% (5N2), the purity reaches 5N, and each impurity component is less than 1ppm, preparing a 5N electronic-grade product.

[0127] Table 7 Physical properties of electronic grade disilane products

[0128]

[0129] Through this embodiment, the crude disilane product is separated and purified by multi-stage low-temperature precision distillation and synergistic separation technology, and high-purity electronic-grade disilane with a product purity of 5N2 and each impurity content less than 1ppm can be prepared; when treating a unit mass of crude disilane and preparing the above-mentioned electronic-grade disilane product, the heat and cold consumed by the light-removal distillation tower are both 740kcal / kg (crude disilane product), and the heat and cold consumed by the heavy-removal distillation tower are both 480kcal / kg (crude disilane product), and the total heat and cold consumed are both 1220kcal / kg (crude disilane product). Compared with the traditional multi-stage low-temperature distillation and adsorption synergistic separation and purification technology used in Example 1, the electronic-grade product obtained has a higher purity, a lower impurity component content, and a lower heat and cold consumption, both of which are reduced by about 12.9%, which is more energy-saving and has obvious technical advantages.

Claims

1. A method for preparing electronic grade disilane, characterized in that: The method mainly uses multi-stage low-temperature precision distillation and targeted adsorption synergistic separation and purification technology to separate and purify crude disilane. That is, firstly, multi-stage low-temperature precision distillation technology is used to completely or mostly remove impurity components in the crude disilane except for impurity components with complex systems such as near-boiling or azeotropic systems, so as to effectively reduce the types and contents of impurity components in the crude disilane. Then, targeted adsorption distillation is used to separate and remove the remaining impurity components, which are completely removed to prepare high-purity electronic-grade disilane products. Among them, the multi-stage low-temperature precision distillation is realized by appropriately increasing the distillation temperature through methods such as pressurization to make the process conditions such as pressure and temperature become milder and precisely controllable, and by using high-precision equipment, instruments and nonlinear control theory to accurately control the operating conditions. The multi-stage distillation includes both light removal distillation and heavy removal distillation. The light removal distillation may be performed first and then the heavy removal distillation, or the heavy removal distillation may be performed first and then the light removal distillation. Preferably, the light removal distillation is performed first and then the heavy removal distillation. The light removal distillation can be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred. The de-weighting distillation may be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred. The precision control of the multi-stage low-temperature precision distillation is achieved through two aspects, namely: A. By changing the distillation pressure and other conditions to increase the distillation temperature, the harsh process conditions during the ultra-low temperature distillation of disilane are reduced, so that the disilane distillation conditions become milder relative to the temperature, and the dependence on harsh ultra-low temperature utilities such as liquid nitrogen cooling is eliminated. Instead, milder utilities such as Freon, ethylene glycol, and even water cooling are used, so that the disilane distillation process conditions are easy to operate under more conventional conditions, and the operability and accuracy of the operation are improved. The distillation temperature can be increased to the atmospheric boiling point of disilane, zero degrees Celsius, or higher, preferably between the atmospheric boiling point of disilane and zero degrees Celsius. B. The mild change in relative temperature of the distillation process enables the use of high-precision equipment and instrumentation that can be used under milder conditions, improving the accuracy of operations. C. Use measurement and control systems that use advanced nonlinear control theory rather than linear control theory to improve the real-time performance and sensitivity of distillation equipment and instrumentation, and improve the accuracy of operations. Targeted adsorption is achieved by using a combination of different types of specialized adsorption materials suitable for adsorbing different impurity components to achieve precise adsorption of different impurity components. The adsorption material may be activated carbon or molecular sieve, or silica gel or other porous medium materials, preferably molecular sieve. The method for preparing electronic grade disilane mainly includes two parts, namely, multi-stage low-temperature precision distillation and targeted adsorption, as follows: A. Multi-stage cryogenic precision distillation A certain flow of crude disilane (sub) is introduced into the multi-stage distillation system through the air inlet of the de-light distillation tower of the multi-stage distillation system for distillation separation. First, de-light distillation is carried out in the de-light distillation tower, and the top pressure of the de-light distillation tower (referred to as the light top pressure) is adjusted to positive pressure, so that the de-light distillation is pressurized distillation, and the top temperature of the de-light distillation tower (referred to as the light top temperature) is higher than the boiling point of disilane under normal pressure. Under this distillation condition, freon and other milder heating and cooling media and other public works are used, and high-precision flow measurement and control components, temperature measurement and control components, pressure measurement and control components and other equipment and instruments are used. At the same time, non-linear The control theory logic module can precisely control the above-mentioned equipment and instruments to achieve precise control of parameters such as the feed flow rate of the de-light distillation tower (referred to as light feed), the heating medium flow rate of the de-light distillation tower (light heat), the cooling medium flow rate of the de-light distillation tower (light cooling), the top temperature of the de-light distillation tower (light top temperature), the top pressure of the de-light distillation tower (light top pressure), the bottom temperature of the de-light distillation tower (referred to as light bottom temperature), the bottom pressure of the de-light distillation tower (referred to as light bottom pressure), the reflux amount of the de-light distillation tower (referred to as light reflux), the top product flow rate of the de-light distillation tower (referred to as light top amount), and the bottom product flow rate of the de-light distillation tower (referred to as light bottom amount). Under the precise control of the de-light distillation operation parameters, the crude disilane entering the de-light distillation tower enters the tower kettle and is heated and vaporized by a certain flow of high-temperature de-light distillation tower heating medium introduced through the de-light distillation tower heat inlet. Impurity components with lower boiling points than disilane gradually move to the top of the de-light distillation tower, while disilane and heavy components with higher boiling points than disilane remain in the de-light distillation tower kettle to separate the crude disilane. After heat exchange, the temperature of the high-temperature de-light distillation tower heating medium decreases and becomes the low-temperature de-light distillation tower heating medium and is discharged through the de-light distillation tower heat outlet, and is recycled after treatment. The impurity components with lower boiling points than disilane flow to the upper part of the de-light distillation tower and are discharged from the top of the de-light distillation tower in the form of gas, and are cooled into liquid by a certain flow of low-temperature de-light distillation tower cooling medium introduced through the cold inlet of the de-light distillation tower. After being cooled into liquid, part of it flows back to the top of the dehydrogenation distillation tower, and the remaining part is discharged from the light outlet of the top of the de-light distillation tower at a certain flow rate in the form of de-light distillation light components, and sent to the impurity component processing system for centralized processing. In the crude disilane product, except for complex physical properties such as near boiling or azeotropic, the components with lower boiling points than disilane are completely separated and removed. After heat exchange, the low-temperature de-light distillation tower cooling medium is heated up to become the cold flow medium of the high-temperature de-light distillation tower and is discharged from the cold outlet of the de-light distillation tower, and is recycled after treatment. The disilane and components with higher boiling points than disilane remaining in the kettle of the de-light fractionation tower are discharged from the heavy outlet at the bottom of the de-light fractionation tower at a certain flow rate in the form of de-light fractionation heavy components. The heavy components of the light degassing distillation are discharged from the bottom of the light degassing distillation tower and enter the heavy degassing distillation tower at a certain flow rate through the feed port of the heavy degassing distillation tower for heavy degassing distillation. The pressure at the top of the light degassing distillation tower is adjusted to positive pressure, so that the heavy degassing distillation is pressurized distillation, and the temperature at the top of the heavy degassing distillation tower is higher than the boiling point of disilane under normal pressure. Under this distillation condition, freon and other milder heating and cooling media and other public works are used, and high-precision flow measurement and control elements, temperature measurement and control elements, pressure measurement and control elements and other equipment and instruments are used. At the same time, the nonlinear control theory logic module is used to accurately control the above equipment and instruments. Accurate control is achieved to realize precise control of parameters such as the feed flow rate of the weight removal distillation tower (referred to as heavy feed), the heating medium flow rate of the weight removal distillation tower (heavy heat), the cooling medium flow rate of the weight removal distillation tower (referred to as heavy cooling), the top temperature of the weight removal distillation tower (referred to as heavy top temperature), the top pressure of the weight removal distillation tower (referred to as heavy top pressure), the kettle temperature of the weight removal distillation tower (referred to as heavy kettle temperature), the kettle pressure of the weight removal distillation tower (referred to as heavy kettle pressure), the reflux amount of the weight removal distillation tower (referred to as heavy reflux), the top product flow rate of the weight removal distillation tower (referred to as heavy top amount), and the bottom product flow rate of the weight removal distillation tower (referred to as heavy bottom amount). Under the precise control of the de-heavy distillation operating parameters, the heavy components of the de-light distillation enter the de-heavy distillation tower kettle and are heated and vaporized by a certain flow of high-temperature de-heavy distillation tower heating medium introduced from the de-heavy distillation tower heat inlet. Disilane gradually moves to the top of the de-light distillation tower, while the heavy components with higher boiling points than disilane remain in the de-heavy distillation tower kettle, separating the heavy components of the de-light distillation. After heat exchange, the temperature of the high-temperature de-heavy distillation tower heating medium decreases and becomes the low-temperature de-heavy distillation tower heating medium and is discharged through the de-heavy distillation tower heat outlet, and is recycled after treatment. Except for complex physical impurity components such as near-boiling or azeotropic impurities and trace impurity components such as metal ions, components with boiling points higher than disilane remaining in the kettle of the de-heavy distillation tower are completely separated and removed, and discharged from the bottom heavy outlet of the de-heavy distillation tower at a certain flow rate in the form of de-heavy distillation heavy components, and sent to the impurity component processing system for centralized treatment. The components mainly composed of disilane flow to the upper part of the de-heavy distillation tower and are discharged from the top of the de-heavy distillation tower in the form of gas, and are cooled into liquid by a certain flow of low-temperature de-heavy distillation tower cooling medium introduced through the cold inlet of the de-heavy distillation tower. After being cooled into liquid, a part of it flows back to the top of the de-heavy distillation tower, and the remaining part is discharged from the light outlet of the top of the de-heavy distillation tower at a certain flow rate in the form of de-heavy distillation light components, thereby completely separating and removing the components with lower boiling points than disilane in the crude disilane except for complex physical properties such as near boiling or azeotropic. After heat exchange, the low-temperature de-heavy distillation tower cooling medium is heated up to become the high-temperature de-heavy distillation tower cold flow medium and is discharged from the cold outlet of the de-heavy distillation tower, and is recycled after treatment. Through multi-stage low-temperature precision distillation, precise distillation and separation of various impurity components in the crude disilane product are achieved, and impurity components with complex physical properties such as near-boiling or azeotropic are completely removed, which greatly reduces the types and contents of impurity components in the crude disilane product and increases the content of main component disilane in the crude disilane product; at the same time, due to the subsequent adsorption separation treatment, in the multi-stage low-temperature precision distillation separation process, there is no need to remove impurity components with complex physical properties such as near-boiling or azeotropic and trace impurities such as metal ions with very low content and great difficulty in removal, and the multi-stage low-temperature precision distillation load is small and the energy consumption is low. B. Targeted adsorption The light components of the de-heavy distillation discharged from the bottom of the de-heavy distillation tower are introduced into an adsorption system filled with different adsorption materials through the feed port of the adsorption system for adsorption separation. The impurity components with complex physical properties such as near-boiling or azeotropic properties and trace impurity components such as metal ions remaining in the light components of the de-heavy distillation are adsorbed, separated and removed by different special adsorption materials, thereby preparing high-purity electronic-grade disilane. The removed impurities are discharged and then processed centrally. A device for realizing a method for preparing electronic-grade disilane mainly includes a multi-stage low-temperature precision distillation system and a targeted adsorption system. The multi-stage low-temperature precision distillation system is mainly used to perform precision distillation and separation on crude disilane, remove most of the impurity components except for impurity components with complex physical properties such as near-boiling or azeotropic properties and trace impurity components such as metal ions, and reduce the types and contents of impurity components in the crude disilane. It mainly includes a light removal distillation tower, a heavy removal distillation tower and a nonlinear control theory logic module. The light removal distillation tower is mainly used to remove light components composed of impurity components with a lower boiling point than disilane. Its feeding port is connected to the disilane crude product supply system, the heat inlet is connected to the heating medium system for the light removal distillation tower, the heat outlet is connected to the heating medium system for the light removal distillation tower, the heavy outlet is connected to the feeding port of the heavy removal distillation tower, the cold inlet is connected to the cooling medium system for the light removal distillation tower, the cold outlet is connected to the cooling medium system for the light removal distillation tower, and the light outlet is connected to the impurity component processing system; the measurement and control elements of parameters such as light feeding, light heat, light cooling, light top temperature, light top pressure, light kettle temperature, light kettle pressure, light reflux, light top amount, light bottom amount, etc. installed thereon are all high-precision equipment and instruments, and are connected to and accurately controlled by the nonlinear control theory logic module. Among them, the light removal distillation tower can be a single-stage distillation tower or a two-stage or more multi-stage distillation tower, preferably a single-stage distillation tower; it can be a packed tower, a plate tower, or a composite tower of packings and tower plates, preferably a packed tower. The de-heavy distillation tower is mainly used to remove heavy components composed of impurity components with a boiling point higher than that of disilane. Its feed port is connected to the heavy outlet of the de-light distillation tower, the heat inlet is connected to the heating medium system for the de-heavy distillation tower, the heat outlet is connected to the heating medium system for the de-heavy distillation tower, the heavy outlet is connected to the impurity component processing system, the cold inlet is connected to the cooling medium system for the de-heavy distillation tower, the cold outlet is connected to the cooling medium system for the de-heavy distillation tower, and the light outlet is connected to the targeted adsorption system; the measurement and control elements of parameters such as heavy feed, heavy heat, heavy cooling, heavy top temperature, heavy top pressure, heavy kettle temperature, heavy kettle pressure, heavy reflux, heavy top amount, and heavy bottom amount installed thereon are all high-precision equipment and instruments, and are connected to and accurately controlled by a nonlinear control theory logic module. Among them, the de-weighting distillation tower can be a single-stage distillation tower or a two-stage or more multi-stage distillation tower, preferably a single-stage distillation tower; it can be a packed tower, a plate tower, or a composite tower of packings and tower plates, preferably a packed tower. The nonlinear control theory logic module uses a nonlinear theory method to control the high-precision measurement and control elements installed on the light removal distillation tower and the heavy removal distillation tower, so as to realize high-precision analysis, detection and control of these measurement and control elements. It is connected to the measurement and control elements of parameters such as light feed, light heat, light cooling, light top temperature, light top pressure, light kettle temperature, light kettle pressure, light reflux, light top amount, light bottom amount, heavy feed, heavy heat, heavy cooling, heavy top temperature, heavy top pressure, heavy kettle temperature, heavy kettle pressure, heavy reflux, heavy top amount and heavy bottom amount on the light removal distillation tower and the heavy removal distillation tower, and controls them. The targeted adsorption system is mainly used to further separate and purify the crude disilane after multi-stage cryogenic precision distillation separation and purification, deeply remove impurities in the crude disilane, and prepare high-purity electronic grade disilane. Its feed port is connected to the light outlet of the de-heavy distillation tower of the multi-stage cryogenic precision distillation system, the disilane outlet is connected to the disilane product storage system, and the impurity outlet is connected to the impurity treatment system. Among them, the targeted adsorption system is composed of special adsorption materials suitable for adsorbing different impurity components. The special adsorption materials have a specific targeted adsorption function for one or several types of impurity components, but have weaker or no adsorption function for other components. The type of special adsorption material is determined according to the type and quantity of impurities in the crude disilane, and various adsorption materials are loaded in the corresponding equipment.

2. The method according to claim 1, characterized in that The method mainly uses multi-stage low-temperature precision distillation and targeted adsorption synergistic separation and purification technology to separate and purify crude disilane. That is, firstly, multi-stage low-temperature precision distillation technology is used to completely or mostly remove impurity components in the crude disilane except for impurity components with complex systems such as near-boiling or azeotropic systems, so as to effectively reduce the types and contents of impurity components in the crude disilane. Then, targeted adsorption distillation is used to separate and remove the remaining impurity components, which are completely removed to prepare high-purity electronic-grade disilane products.

3. As claimed in claims 1 and 2, characterized in that The multi-stage low-temperature precision distillation is achieved by appropriately increasing the distillation temperature by methods such as pressurization to make process conditions such as pressure and temperature milder and precisely controllable, and by using high-precision equipment and instruments and nonlinear control theory to accurately control operating conditions.

4. As claimed in claims 1, 2 and 3, characterized in that The multi-stage distillation includes both light removal distillation and heavy removal distillation. The light removal distillation may be performed first and then the heavy removal distillation, or the heavy removal distillation may be performed first and then the light removal distillation. Preferably, the light removal distillation is performed first and then the heavy removal distillation. The light removal distillation can be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred. The de-weighting distillation may be a single-stage distillation or a two-stage or more multi-stage distillation, and a single-stage distillation is preferred.

5. As claimed in claims 1 and 2, characterized in that The targeted adsorption is achieved by using a combination of different types of special adsorption materials suitable for adsorbing different impurity components to achieve precise adsorption of different impurity components. The adsorption material may be activated carbon or molecular sieve, or silica gel or other porous medium materials, preferably molecular sieve.

6. The electronic grade disilane preparation device according to claim 1, characterized in that: The device mainly comprises a multi-stage low-temperature precision distillation system and a targeted adsorption system.

7. As claimed in claims 1 and 6, characterized in that The multi-stage low-temperature precision distillation system mainly includes a light removal distillation tower, a heavy removal distillation tower and a nonlinear control theory logic module. The light removal distillation tower can be a single-stage distillation tower or a two-stage or more multi-stage distillation tower, preferably a single-stage distillation tower; it can be a packed tower, a plate tower, or a composite tower of packings and plates, preferably a packed tower. The de-weighting distillation tower can be a single-stage distillation tower or a two-stage or more multi-stage distillation tower, preferably a single-stage distillation tower; It can be a packed tower, a plate tower, or a composite tower of packing and plates, preferably a packed tower. The nonlinear control theory logic module uses a nonlinear theory method to control the high-precision measurement and control elements installed on the light-removal distillation tower and the heavy-removal distillation tower, thereby realizing high-precision analysis, detection and control of these measurement and control elements.

8. As claimed in claims 1 and 6, characterized in that The targeted adsorption system is composed of special adsorption materials suitable for adsorbing different impurity components. The special adsorption materials have a specific targeted adsorption function for one or several types of impurity components, but have weaker or no adsorption function for other components. The type of special adsorption material is determined according to the type and amount of impurities in the crude disilane, and various adsorption materials are loaded in the corresponding equipment.

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