Device and process for purifying impurity gas in disilane product synthesized from silane

Abstract

The invention relates to a device and a process for purifying impurity gas in a disilane product synthesized from silane. The device comprises a gas inlet system, an adsorption system and a rectification system, the adsorption system comprises a first adsorption tower and a first vacuum pump for desorbing the first adsorption tower, and the first adsorption tower is communicated with the gas inlet system; the rectification system comprises a first rectification tower and a second rectification tower; the first rectification tower is communicated with the first adsorption tower through a first vacuum pump; the second rectifying tower is communicated with the first rectifying tower; the process comprises the following steps: adsorbing sample gas by a first adsorption tower; feeding gas into a first rectifying tower through a first vacuum pump; the first rectifying tower bottom material enters a second rectifying tower; a product disilane gas is obtained from the top of the second rectifying tower. According to the invention, high-content hydrogen, argon, helium and other light components in the product gas are adsorbed, and are primarily separated from silane, disilane, trisilane and the like. And compared with a gas-liquid separation mode only adopting condensation, the energy consumption and the disilane product loss in the purification process can be obviously reduced.

Description

Technical Field

[0001] The present application belongs to the field of impurity gas separation, and specifically relates to a device and process for purifying impurity gas in a disilane product synthesized from silane. Background Art

[0002] Disilane is a silicon-based electronic specialty gas widely used in the integrated circuit and solar cell related industries. Due to its advantages such as fast film formation rate, film density, good quality and suitable process conditions, disilane is widely used in silicon wafer epitaxial growth, amorphous silicon thin film deposition and other processes, and these special applications also have high requirements for the purity of disilane. At present, the widely used disilane synthesis processes in industry are mainly the synthesis process of magnesium silicide and halogenated ammonia or hydrochloric acid reaction, and the process of silane cracking synthesis of disilane. Since the direct silane synthesis method is relatively simple and involves fewer types of by-products and impurities, it has been widely used in industry. Among them, the silane cracking synthesis method includes thermal cracking, discharge cracking, photolysis and other methods according to the different external energy. Generally, the silane cracking method requires the use of hydrogen, helium or argon as a diluent gas. In addition, high-order silane polymers will be produced in the silane cracking process, which poses a challenge to the efficient removal of impurities such as light components and heavy components in the product.

[0003] CN112663074B discloses a system for electrocatalytic synthesis of high-purity disilane, comprising: an electrocatalytic reactor, a buffer tank, a gas compression device, a hydrogen separation device and a disilane separation and purification device. The reaction process obtains a mixed gas of monosilane, hydrogen, disilane and higher silane. The light component gas such as hydrogen is removed by compression and gas-liquid separation, while the heavy component such as higher silane is removed by distillation separation. Similarly, CN115477305A uses rectification or distillation to remove impurities such as hydrogen and higher-order silane in the reaction product by utilizing the difference in boiling points.

[0004] The above patents all show that for the mixed gas of monosilane, hydrogen, disilane, and high silane produced by the silane reaction, the commonly used method is to utilize the difference in boiling points between the components, and to separate them by pressurization or deep cooling through gas-liquid separation, distillation or distillation. This method requires the use of a compressor for pressurization and deep cooling, which consumes a lot of energy and has a large equipment investment cost, especially for the separation process of light components such as hydrogen, argon and helium, and heavy components such as high silane with a large impurity content. The light component content is high, the condensation consumes more energy, and the condensation effect is poor. When the high silane content is high, due to its high boiling point, the use of low-temperature distillation will cause it to solidify, resulting in poor distillation effect, and even blockage and damage to the equipment. The energy consumption and equipment investment will also increase accordingly, which is not conducive to actual industrial production. Summary of the invention

[0005] In order to optimize the defects of the separation method in the prior art, the present application provides a device and process for purifying impurity gases in the product of disilane synthesis from silane.

[0006] In the first aspect, the present application discloses a device for purifying impurity gas in a disilane product synthesized from silane, which adopts the following technical solution:

[0007] A device for purifying impurity gas in a disilane product synthesized from silane, comprising an air intake system, characterized in that it also comprises an adsorption system and a distillation system;

[0008] The adsorption system comprises a first adsorption tower and a first vacuum pump for desorbing the first adsorption tower, and the first adsorption tower is connected to the air intake system;

[0009] The distillation system comprises a first distillation tower and a second distillation tower, wherein the first distillation tower is connected to the first adsorption tower via a first vacuum pump; and the second distillation tower is connected to the first distillation tower.

[0010] In a specific implementation scheme, the adsorption system further includes a second adsorption tower, and the second adsorption tower and the first adsorption tower are both connected to the air intake system; after the second adsorption tower and the first adsorption tower are connected in parallel, they are connected in series with the first vacuum pump.

[0011] In a specific possible implementation scheme, the adsorption system further includes a third adsorption tower, a fourth adsorption tower and a second vacuum pump for desorbing the third adsorption tower and the fourth adsorption tower; the third adsorption tower and the fourth adsorption tower are both connected to the air intake system; after the third adsorption tower and the fourth adsorption tower are connected in parallel, they are connected to the first distillation tower through the second vacuum pump in series.

[0012] In a second aspect, the present application provides a process for purifying impurity gases in a disilane product synthesized from silane, using the following technical solution:

[0013] A purification process for impurity gas in a disilane product synthesized from silane comprises the following steps:

[0014] Step 1: The sample gas passes through the first adsorption tower at normal temperature and pressure, and the first adsorption tower adsorbs the sample gas;

[0015] Step 2: During desorption, the operating pressure is less than -0.095 MPa, the temperature is room temperature, and the gas is sent to the first distillation tower through the first vacuum pump;

[0016] Step 3: The operating pressure of the first distillation tower is 0.065-0.08 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C; silane gas is obtained at the top of the tower, and the bottom material enters the second distillation tower;

[0017] Step 4: The bottom materials of the first distillation tower (5) are combined and fed into the second distillation tower. The operating pressure of the second distillation tower is 0.055-0.06 MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained at the top of the tower.

[0018] In a specific implementation scheme, the volume composition of the sample gas in step 1 is: the content of hydrogen, argon and helium is 75% to 85%, the content of silane is 12% to 22%, and the remainder is the sum of disilane and trisilane.

[0019] In a specific feasible implementation scheme, in step 1, at normal temperature and pressure, the first adsorption tower uses any one of molecular sieves with a pore size of 0.3nm to 0.5nm, activated carbon and carbon fiber, metal-loaded molecular sieves, metal-loaded activated carbon and carbon fiber, ionic liquid-loaded activated carbon and carbon fiber, and adsorption resin as an adsorbent.

[0020] In a third aspect, the present application discloses a process for purifying impurity gases in a disilane product synthesized from silane, using the following technical solution:

[0021] A purification process for impurity gas in a disilane product synthesized from silane comprises the following steps:

[0022] Step 1: The sample gas passes through the first adsorption tower / the second adsorption tower at normal temperature and pressure, and the first adsorption tower / the second adsorption tower adsorbs the sample gas;

[0023] Step 2: During desorption, the operating pressure is less than -0.095MPa, the temperature is room temperature, and the gas adsorbed in the first adsorption tower / the second adsorption tower is sent to the first distillation tower through the first vacuum pump; during desorption, the conditions of the second adsorption tower and the idle adsorption tower in the first adsorption tower are switched to room temperature and pressure, and the idle adsorption tower is used to adsorb the sample gas;

[0024] Step 3: The operating pressure of the first distillation tower is 0.065-0.08 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C; silane gas is obtained at the top of the tower, and the bottom material enters the second distillation tower;

[0025] Step 4: The bottom materials of the first distillation tower are combined and enter the second distillation tower. The operating pressure of the second distillation tower is 0.055-0.06MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C; the product disilane gas is obtained at the top of the tower.

[0026] In a fourth aspect, the present application discloses a process for purifying impurity gases in a disilane product synthesized from silane, using the following technical solution:

[0027] A purification process for impurity gas in a disilane product synthesized from silane comprises the following steps:

[0028] The sample gas passes through the first adsorption tower / the second adsorption tower at normal temperature and pressure, and the first adsorption tower / the second adsorption tower adsorbs the sample gas;

[0029] During desorption, the operating pressure is less than -0.095MPa, the temperature is room temperature, and the gas adsorbed in the first adsorption tower / the second adsorption tower is sent to the first distillation tower through the first vacuum pump; during desorption, the conditions of switching the second adsorption tower and the idle adsorption tower in the first adsorption tower to room temperature and pressure, and the idle adsorption tower is used to adsorb the sample gas;

[0030] The operating pressure of the first distillation tower is 0.065~0.08MPa, the top temperature is -90~-65℃, and the bottom temperature is 0~10℃; silane gas is obtained at the top of the tower, and the bottom material enters the second distillation tower;

[0031] The bottom materials of the first distillation tower are combined and enter the second distillation tower. The operating pressure of the second distillation tower is 0.055-0.06MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained at the top of the tower.

[0032] When the first adsorption tower and the second adsorption tower stop working due to the replacement of adsorbent or other reasons, the third adsorption tower and the fourth adsorption tower will replace the first adsorption tower and the second adsorption tower and put into production accordingly.

[0033] The present application includes at least one of the following beneficial technical effects:

[0034] The present application uses an adsorption method to initially separate light components such as high-content hydrogen, argon and helium in the product gas of disilane synthesized from silane from silane, from silane, disilane and trisilane. Compared with the condensation gas-liquid separation method alone, the energy consumption of the purification process and the loss of disilane products can be significantly reduced;

[0035] This application adopts pressure swing adsorption, combined with a distillation purification process and an ingenious design of parallel conjugate adsorption towers. Compared with other purification processes, the process is simpler, and the operation is more continuous and automated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of a device for purifying impurity gases in a disilane product synthesized from silane provided in Example 1.

[0037] Figure 2 This is a schematic diagram of a device for purifying impurity gases in a disilane product synthesized from silane provided in Example 2.

[0038] Figure 3 This is a schematic diagram of a device for purifying impurity gases in a disilane product synthesized from silane, as provided in Example 3.

[0039] Figure 4This is the GC detection chart of the intake gas in step 1 of Example 4.

[0040] Figure 5 This is a GC detection chart showing the purity of the product disilane after purification in Example 4.

[0041] Figure 6 This is the GC detection chart of the intake gas in step 1 of Example 5.

[0042] Figure 7 This is a GC detection chart showing the purity of the product disilane after purification in Example 5.

[0043] Figure 8 This is the GC detection chart of the intake gas in step 1 of Example 6.

[0044] Fig. 9 This is a GC detection chart showing the purity of the product disilane after purification in Example 6.

[0045] Explanation of the accompanying drawings: 1. first adsorption tower; 2. second adsorption tower; 3. third adsorption tower; 4. fourth adsorption tower; 5. first distillation tower; 6. second distillation tower; 7. first vacuum pump; 8. second vacuum pump. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-9 This application is described in further detail.

[0047] In the prior art, when silane is used to synthesize disilane, the product gas contains a large amount of light component impurities such as hydrogen, argon and helium, as well as a small amount of trisilane (high silane) impurities. For the purification of the product gas of this composition, if distillation or rectification is used to separate the gas-liquid two-phase by using the difference in boiling points, it will result in a large energy consumption. Because the content of light component impurities in the product is high, the heat transfer effect of the product gas is poor, and a large amount of cold energy or high-pressure compression is required to liquefy it. This method will also result in a high loss of disilane product gas. Through continuous research by the applicant, it is found that the product gas can be effectively separated by utilizing the different adsorption amounts of different components in the product gas of silane synthesis disilane by the adsorbent under different pressures. The types of adsorbents used include molecular sieves, activated carbon and carbon fibers, metal-loaded molecular sieves, metal-loaded activated carbon and carbon fibers, ionic liquid-loaded activated carbon and carbon fibers, and adsorption resins. The pore size of the adsorbent used is in the range of 0.3nm to 0.5nm. Adsorption separation is performed by utilizing the different molecular sizes and adsorption capacities of different components under different pressures. Under normal pressure, the adsorbent has a weak adsorption capacity for light components such as hydrogen, helium and argon in the product gas, but a strong adsorption capacity for silane, disilane and trisilane, which can be adsorbed on the adsorbent, while light components such as hydrogen, helium and argon are discharged to tail gas treatment through the adsorption tower. After the adsorption is saturated, the saturated tower is transferred to the vacuum desorption state. Under vacuum conditions, the adsorption capacity of silane, disilane and trisilane decreases. After desorption from the adsorbent, it is transported to the distillation tower through a vacuum pump for purification and separation. At this point, the preliminary separation of silane, disilane and trisilane and light components such as hydrogen, helium and argon in the product gas is completed, which can greatly reduce the energy consumption of distillation.

[0048] After proposing the above technical solution, the applicant also found that continuous production can be achieved and production efficiency can be improved by rationally arranging and improving the purification device.

[0049] The technical solution of the present application will be further described below with respect to specific device embodiments and process embodiments, as well as detection graphs.

[0050] Example 1

[0051] The present embodiment provides a device for purifying impurity gas in the product of disilane synthesized from silane, the device comprising an adsorption system and a distillation system, the adsorption system comprising a first adsorption tower 1 and a first vacuum pump 7, the distillation system comprising a first distillation tower 5 and a second distillation tower 6; an air inlet is provided at the bottom of the first adsorption tower 1 for the intake of sample gas; an air outlet is provided on the first adsorption tower 1 for connecting with the first distillation tower 5 through a pipeline; the first vacuum pump 7 is arranged in a pipeline connecting the first adsorption tower 1 and the first distillation tower 5, for vacuum pumping the adsorbed gas in the first adsorption tower 1 into the first distillation tower 5 in a desorption state. An air outlet is provided at the top of the first distillation tower 5, and the air outlet is connected to a silane recovery system; the bottom of the first distillation tower 5 is connected to the second distillation tower 6; a product outlet is provided at the top of the second distillation tower 6 for releasing disilane product gas; an impurity outlet is provided at the bottom of the second distillation tower 6, and the impurity outlet is connected to a high silane treatment system.

[0052] The top of the first adsorption tower 1 is connected to a tail gas treatment system, and light components such as hydrogen, argon and helium that are not adsorbed by the first adsorption tower 1 pass through the first adsorption tower 1 and enter the tail gas treatment system.

[0053] The adsorbent used in the first adsorption tower 1 can be molecular sieve, activated carbon and carbon fiber, metal-loaded molecular sieve, metal-loaded activated carbon and carbon fiber, ionic liquid-loaded activated carbon and carbon fiber, and adsorption resin, etc. The pore size of the adsorbent is 0.3nm to 0.5nm. Further, an adsorbent loaded with iron or copper is preferred, because the adsorbent loaded with iron or copper has no catalytic activity to silane and disilane, and can retain the product gas to a large extent.

[0054] In this embodiment, the adsorbent in the first adsorption tower 1 is copper ion loaded activated carbon fiber.

[0055] The first distillation tower 5 uses structured packing or random packing to distill and purify silane, disilane and trisilane desorbed from the first adsorption tower 1, wherein silane is obtained at the top of the first distillation tower 5 and enters the recovery system for recycling, and disilane and trisilane are obtained at the bottom of the tower and enter the second distillation tower 6.

[0056] The second distillation tower 6 uses structured packing or random packing to separate and purify disilane and trisilane at the bottom of the first distillation tower 5, wherein the product disilane is obtained at the top of the second distillation tower 6, and the impurity trisilane is obtained at the bottom.

[0057] The layout of the pipelines and the settings of the valves are not explained in detail in this embodiment. Those skilled in the art can make changes based on the actual site without creative work. This is a very mature prior art and will not be described in detail here.

[0058] The implementation principle of this embodiment is as follows: the sample gas is first introduced into the first adsorption tower 1, and the first vacuum pump 7 is kept closed. At this time, the adsorbent has a weak adsorption capacity for light components such as hydrogen, helium and argon in the product gas, but a strong adsorption capacity for silane, disilane and trisilane, which can be adsorbed on the adsorbent, while light components such as hydrogen, helium and argon are discharged to tail gas treatment through the adsorption tower; when the first adsorption tower 1 adsorbs silane, disilane and trisilane in the sample gas to saturation, the introduction of the sample gas is stopped, and then the first vacuum pump 7 is turned on to desorb the silane, disilane and trisilane adsorbed in the first adsorption tower 1, and successively introduce them into the first distillation tower 5 and the second distillation tower 6 for purification and separation, thereby completing the purification of the gas.

[0059] Example 2

[0060] This embodiment is based on the scheme of Embodiment 1, and further comprises: the adsorption system of this embodiment also includes a second adsorption tower 2 which is the same as the first adsorption tower 1, the second adsorption tower 2 and the first adsorption tower 1 are arranged in parallel and in parallel, and the sample gas can selectively enter the first adsorption tower 1 or the second adsorption tower 2 through valve switching; the first adsorption tower 1 and the second adsorption tower 2 are first connected in parallel, and then connected in series with the first vacuum pump 7.

[0061] It is also possible to respectively arrange two identical vacuum pumps on the first adsorption tower 1 and the second adsorption tower 2, which is an equivalent replacement of the above technical solution.

[0062] The implementation principle of this embodiment is: when the first adsorption tower 1 is saturated with adsorption or reaches a sufficient degree of adsorption according to the technical solution described in Example 1, the first adsorption tower 1 desorbs the adsorbed gas; and during the desorption process of the first adsorption tower 1, the operator can switch the air intake to the second adsorption tower 2 to achieve the adsorption operation of the second adsorption tower 2. After the desorption of the first adsorption tower 1 is completed, the sample gas can be injected into the first adsorption tower 1 to complete the adsorption, and the second adsorption tower 2 can start desorption at this time. Therefore, the second adsorption tower 2 is connected in parallel next to the first adsorption tower 1, which can further complete the continuous purification production, optimize the technical solution of Example 1, and is more conducive to meeting actual production needs.

[0063] Furthermore, in order to further realize continuous operation of the first adsorption tower 1 and the second adsorption tower 2, the applicant also provides the following parameters: Assuming that the intake gas flow rate is a cubic meter / h, the adsorbent volume is not less than 0.1a cubic meter, and the ratio of the height and diameter of the adsorption tower is not less than 4 / 1. In this state, the intake gas enters the first adsorption tower 1 for adsorption for t hours, and the intake gas enters the second adsorption tower 2 after t hours. At this time, the first adsorption tower 1 is decomposed, which takes 0.5t hours, and the remaining time is in standby mode. After t hours of adsorption, the second adsorption tower 2 can seamlessly transfer to the first adsorption tower 1 to continue adsorption.

[0064] Example 3

[0065] This embodiment is based on the technical solution of Embodiment 2 and further includes: a backup adsorption system.

[0066] The standby adsorption system includes a third adsorption tower 3, a fourth adsorption tower 4 and a second vacuum pump 8; the third adsorption tower 3 and the fourth adsorption tower 4 are parallel to each other and connected in parallel, the bottoms of the third adsorption tower 3 and the fourth adsorption tower 4 are connected to the intake system of the sample gas, and the tops of the third adsorption tower 3 and the fourth adsorption tower 4 are connected to the tail gas treatment system; after the third adsorption tower 3 and the fourth adsorption tower 4 are connected in parallel, they are connected to the first distillation tower 5 through a pipeline. The second vacuum pump 8 is arranged in the pipeline connecting the first distillation tower 5 and the third adsorption tower 3 and the fourth adsorption tower 4, and its role in cooperating with the third adsorption tower 3 and the fourth adsorption tower 4 is the same as the role of the first vacuum pump 7 in cooperating with the first adsorption tower 1 and the second adsorption tower 2.

[0067] The first adsorption tower 1 and the second adsorption tower 2 are recorded as "conjugate adsorption towers", that is, a group of two identical adsorption towers, one for desorption and the other for adsorption, so as to realize continuous production; based on the technical scheme of Example 2, this embodiment adds an additional group of "conjugate adsorption towers", so that the first adsorption tower 1, the second adsorption tower 2, the third adsorption tower 3, and the fourth adsorption tower 4 are backup for each other. When the adsorbent of the first adsorption tower 1 and the second adsorption tower 2 needs to be replaced, the air intake is switched to the third adsorption tower 3 and the fourth for adsorption and desorption, thereby optimizing the continuous production and purification capacity of the device.

[0068] Example 4

[0069] This embodiment provides a purification process for impurity gas in the product of disilane synthesized from silane based on a purification device for impurity gas in the product of disilane synthesized from silane provided in Example 3. The process comprises:

[0070] Step 1: Synthesis of disilane from silane Product gas, in which the volume content of hydrogen, argon and helium is 75%, the volume content of silane is 22%, and the balance is disilane and trisilane. See the analysis chart Figure 4 . Passing through the first adsorption tower 1 or the second adsorption tower 2 in the adsorption state (the adsorption state means that the operating pressure is normal pressure and the temperature is normal temperature); the first adsorption tower 1 or the second adsorption tower 2 adsorbs most of the silane, disilane and trisilane in the silane synthesis disilane reaction gas. The light components such as hydrogen, argon and helium that are not adsorbed enter the tail gas treatment system.

[0071] Step 2: After desorption in the first adsorption tower 1 or the second adsorption tower 2 in the desorption state, the gas is sent to the first distillation tower 5 via the first vacuum pump 7 to deliver the desorbed gas (mainly silane, disilane and trisilane). The desorption state means that the operating pressure is less than -0.095 MPa and the temperature is room temperature.

[0072] The third adsorption tower 3 and the fourth adsorption tower 4 are backup towers for the first adsorption tower 1 and the second adsorption tower 2, and the equipment and operating conditions are the same. When the adsorbent in the first adsorption tower 1 and the second adsorption tower 2 needs to be replaced, the air intake is switched to the third adsorption tower 3 and the fourth adsorption tower 4 for adsorption and desorption.

[0073] Step 3: The operating pressure of the first distillation tower 5 is 0.075-0.08 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C. Silane gas is obtained from the top of the first distillation tower 5 and enters the recovery system for recycling. The bottom material enters the second distillation tower 6.

[0074] Step 4: The bottom materials of the first distillation tower 5 are combined and sent to the second distillation tower 6. The operating pressure of the second distillation tower 6 is 0.055-0.06MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained from the top of the second distillation tower 6, and the purity reaches more than 99.999%. The analysis chart is shown in Figure 5 The materials including trisilane at the bottom of the second distillation tower 6 enter the treatment system for treatment.

[0075] Example 5

[0076] This embodiment provides a purification process for impurity gas in the product of disilane synthesized from silane based on a purification device for impurity gas in the product of disilane synthesized from silane provided in Example 3. The process comprises:

[0077] Step 1: Synthesis of disilane from silane Product gas, in which the volume content of hydrogen, argon and helium is 85%, the volume content of silane is 12%, and the balance is disilane and trisilane. See the analysis chart Figure 6 The first adsorption tower 1 or the second adsorption tower 2 in the adsorption state adsorbs most of the silane, disilane and trisilane in the silane synthesis disilane reaction gas. The unabsorbed light components such as hydrogen, argon and helium enter the tail gas treatment system.

[0078] Step 2: The desorbed gas from the first adsorption tower 1 or the second adsorption tower 2 in the desorption state is sent to the first distillation tower 5 via the first vacuum pump 7 .

[0079] The third adsorption tower 3 and the fourth adsorption tower 4 are backup towers for the first adsorption tower 1 and the second adsorption tower 2, and the equipment and operating conditions are the same. When the adsorbent in the first adsorption tower 1 and the second adsorption tower 2 needs to be replaced, the air intake is switched to the third adsorption tower 3 and the fourth adsorption tower 4 for adsorption and desorption.

[0080] Step 3: The operating pressure of the first distillation tower 5 is 0.065-0.07 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C. Silane gas is obtained from the top of the first distillation tower 5 and enters the recovery system for recycling. The bottom material enters the second distillation tower 6.

[0081] Step 4: The bottom materials of the first distillation tower 5 are combined and sent to the second distillation tower 6. The operating pressure of the second distillation tower 6 is 0.045-0.05MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained from the top of the second distillation tower 6, and the purity reaches more than 99.999%. The analysis chart is shown in Figure 7 The materials including trisilane at the bottom of the tower enter the treatment system for processing.

[0082] Example 6

[0083] This embodiment provides a purification process for impurity gas in the product of disilane synthesized from silane based on a purification device for impurity gas in the product of disilane synthesized from silane provided in Example 3. The process comprises:

[0084] Step 1: Synthesis of disilane from silane Product gas, in which the volume content of hydrogen, argon and helium is 80%, the volume content of silane is 18%, and the balance is disilane and trisilane. See the analysis chart Figure 8 . Passing through the first adsorption tower 1 or the second adsorption tower 2 in the adsorption state; the first adsorption tower 1 or the second adsorption tower 2 adsorbs most of the silane, disilane and trisilane in the silane synthesis disilane reaction gas. The unabsorbed light components such as hydrogen, argon and helium enter the tail gas treatment system.

[0085] Step 2: After the first adsorption tower 1 or the second adsorption tower 2 in the desorption state is desorbed, the gas is sent to the first distillation tower 5 through the first vacuum pump 7. The desorption state means that the operating pressure is less than -0.095 MPa and the temperature is room temperature.

[0086] The third adsorption tower 3 and the fourth adsorption tower 4 are backup towers for the first adsorption tower 1 and the second adsorption tower 2, and the equipment and operating conditions are the same. When the adsorbent in the first adsorption tower 1 and the second adsorption tower 2 needs to be replaced, the air intake is switched to the third adsorption tower 3 and the fourth adsorption tower 4 for adsorption and desorption.

[0087] Step 3: The operating pressure of the first distillation tower 5 is 0.065-0.07 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C. Silane gas is obtained from the top of the first distillation tower 5 and enters the recovery system for recycling. The bottom material enters the second distillation tower 6.

[0088] Step 4: The bottom materials of the first distillation tower 5 are combined and sent to the second distillation tower 6. The operating pressure of the second distillation tower 6 is 0.045-0.05MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained from the top of the second distillation tower 6, and the purity reaches more than 99.999%. The analysis chart is shown in Fig. 9 The materials including trisilane at the bottom of the tower enter the treatment system for processing.

[0089] The above description is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes within the technical scope disclosed in the present application according to the technical solution and improved ideas of the present application, which should be covered by the protection scope of the present application.

Claims

1. A device for purifying impurity gases in a disilane product synthesized from silane, comprising an air intake system, characterized in that: It also includes adsorption systems and distillation systems; The adsorption system comprises a first adsorption tower (1) and a first vacuum pump (7) for desorbing the first adsorption tower (1), and the first adsorption tower (1) is connected to an air intake system; The distillation system comprises a first distillation tower (5) and a second distillation tower (6); the first distillation tower (5) is connected to the first adsorption tower (1) via a first vacuum pump (7); and the second distillation tower (6) is connected to the first distillation tower (5).

2. The device for purifying impurity gas in the product of disilane synthesized from silane according to claim 1, characterized in that: The adsorption system further comprises a second adsorption tower (2), wherein the second adsorption tower (2) and the first adsorption tower (1) are both connected to the air intake system; after the second adsorption tower (2) and the first adsorption tower (1) are connected in parallel, they are connected in series with the first vacuum pump (7).

3. The device for purifying impurity gas in the disilane product synthesized from silane according to claim 2, characterized in that: The adsorption system further comprises a third adsorption tower (3), a fourth adsorption tower (4) and a second vacuum pump (8) for desorbing the third adsorption tower (3) and the fourth adsorption tower (4); the third adsorption tower (3) and the fourth adsorption tower (4) are both connected to an air intake system; after the third adsorption tower (3) and the fourth adsorption tower (4) are connected in parallel, they are connected to the first distillation tower (5) via the second vacuum pump (8) in series.

4. A process for purifying impurity gases in a disilane product synthesized from silane, based on the device for purifying impurity gases in a disilane product synthesized from silane according to claim 1, characterized in that: The steps include: Step 1: The sample gas passes through a first adsorption tower (1) at normal temperature and pressure, and the first adsorption tower (1) adsorbs the sample gas; Step 2: During desorption, the operating pressure is less than -0.095 MPa, the temperature is room temperature, and the gas is sent to the first distillation tower (5) through the first vacuum pump (7); Step 3: The operating pressure of the first distillation tower (5) is 0.065-0.08 MPa, the tower top temperature is -90--65°C, and the tower bottom temperature is 0-10°C; silane gas is obtained at the tower top, and the tower bottom material enters the second distillation tower (6); Step 4: The bottom materials of the first distillation tower (5) are combined and fed into the second distillation tower (6). The operating pressure of the second distillation tower (6) is 0.055-0.06 MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained at the top of the tower.

5. The process for purifying impurity gases in the product of disilane synthesized from silane according to claim 4, characterized in that: The volume composition of the sample gas in step 1 is as follows: the content of hydrogen, argon and helium is 75% to 85%, the content of silane is 12% to 22%, and the remainder is the sum of disilane and trisilane.

6. The process for purifying impurity gases in the product of disilane synthesized from silane according to claim 4, characterized in that: In step 1, at normal temperature and pressure, the first adsorption tower (1) uses any one of molecular sieves with a pore size of 0.3nm to 0.5nm, activated carbon and carbon fiber, metal-loaded molecular sieves, metal-loaded activated carbon and carbon fiber, ionic liquid-loaded activated carbon and carbon fiber, and adsorption resin as an adsorbent.

7. A process for purifying impurity gases in a disilane product synthesized from silane, based on the device for purifying impurity gases in a disilane product synthesized from silane according to claim 2, characterized in that: The steps include: Step 1: The sample gas passes through the first adsorption tower (1) / the second adsorption tower (2) at room temperature and pressure, and the first adsorption tower (1) / the second adsorption tower (2) adsorbs the sample gas; Step 2: During desorption, the operating pressure is less than -0.095 MPa, the temperature is room temperature, and the gas adsorbed in the first adsorption tower (1) / the second adsorption tower (2) is sent to the first distillation tower (5) via the first vacuum pump (7); during desorption, the conditions of the second adsorption tower (2) and the idle adsorption tower in the first adsorption tower (1) are switched to room temperature and pressure, and the sample gas is adsorbed by the idle adsorption tower; Step 3: The operating pressure of the first distillation tower (5) is 0.065-0.08 MPa, the tower top temperature is -90--65°C, and the tower bottom temperature is 0-10°C; silane gas is obtained at the tower top, and the tower bottom material enters the second distillation tower (6); Step 4: The bottom materials of the first distillation tower (5) are combined and fed into the second distillation tower (6). The operating pressure of the second distillation tower (6) is 0.055-0.06 MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained at the top of the tower.

8. A process for purifying impurity gases in a disilane product synthesized from silane, based on the device for purifying impurity gases in a disilane product synthesized from silane according to claim 3, characterized in that: The steps include: The sample gas passes through the first adsorption tower (1) / the second adsorption tower (2) at normal temperature and pressure, and the first adsorption tower (1) / the second adsorption tower (2) adsorbs the sample gas; During desorption, the operating pressure is less than -0.095 MPa, the temperature is room temperature, and the gas adsorbed in the first adsorption tower (1) / the second adsorption tower (2) is sent to the first distillation tower (5) via the first vacuum pump (7); during desorption, the conditions of the second adsorption tower (2) and the idle adsorption tower in the first adsorption tower (1) are switched to room temperature and pressure, and the idle adsorption tower is used to adsorb the sample gas; The operating pressure of the first distillation tower (5) is 0.065-0.08 MPa, the top temperature is -90--65°C, and the bottom temperature is 0-10°C; silane gas is obtained at the top of the tower, and the bottom material enters the second distillation tower (6); The materials at the bottom of the first distillation tower (5) are combined and fed into the second distillation tower (6). The operating pressure of the second distillation tower (6) is 0.055-0.06 MPa, the top temperature is -10-5°C, and the bottom temperature is 20-40°C. The product disilane gas is obtained at the top of the tower. When the first adsorption tower (1) and the second adsorption tower (2) stop working due to replacement of adsorbent or other reasons, the third adsorption tower (3) and the fourth adsorption tower (4) replace the first adsorption tower (1) and the second adsorption tower (2) respectively and go into production.

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