Light component removal device of trichlorosilane rectifying tower

Abstract

The utility model relates to a light component removal device of a trichlorosilane rectifying tower in the field of light component removal tower equipment. A collecting tank is arranged between a distillation chamber and a light component removal chamber of the light component removal tower, the collecting tank is connected with the inner wall of the light component removal tower through an annular shutter, a steam jacket is arranged at the bottom of the distillation chamber, a heat exchange coil pipe is arranged at the bottom of the light component removal chamber, and a liquid return pipe is connected to the bottom of the collecting tank. The distillation chamber is provided with a feed port, a liquid return port and an extraction opening, the feed port is connected with the liquid outlet end of the heat exchange coil pipe, the liquid inlet end of the heat exchange coil pipe is connected with a trichlorosilane feed pipe, the extraction opening is externally connected with a vacuum pump, a reboiler, a condenser and a liquid storage tank are arranged outside the light component removal tower, the reboiler is connected with a collecting tank through a reflux pump, the reboiler is connected with the liquid return port, and the condenser is connected with the liquid storage tank. A gas outlet of the light component removal tower is connected with a condenser, the condenser is connected with a liquid inlet of a liquid storage tank, and the liquid storage tank is connected to a feeding pipe of the light component removal tower through a circulating pump. The heat exchange coil pipe is additionally arranged, waste heat of distillation gas is used for preheating feed, meanwhile, preliminary cooling of evaporation gas is completed, and the use amount of heating steam and the use amount of cooling water of the condenser can be saved at the same time.

Description

Technical Field

[0001] The utility model belongs to the field of lightness removal tower equipment, and specifically relates to a lightness removal device for a trichlorosilane distillation tower. Background Art

[0002] Trichlorosilane, also known as trichlorosilane, silicon chloroform, and silicon form, is an important high value-added industrial raw material. It is mainly used as a raw material for manufacturing ultra-pure polysilicon and high-purity silane in the semiconductor industry and a silicon source for epitaxial growth. High-purity polysilicon is the basic raw material for the electronics industry and the solar photovoltaic industry. In recent years, with the increasing application of solar cells, it has directly driven the rapid growth of polysilicon production capacity, and also indirectly promoted the demand for trichlorosilane production. The trichlorosilane production process includes trichlorosilane synthesis, trichlorosilane distillation and other processes. Trichlorosilane distillation is a purification process that uses a distillation tower to remove light and heavy parts from the trichlorosilane synthesis crude material to separate silicon tetrachloride and trichlorosilane. By heating the trichlorosilane synthesis crude material, the trichlorosilane is distilled out, and then the trichlorosilane product is obtained after condensation and collection. The purity of trichlorosilane directly affects the product quality of polysilicon. The existing trichlorosilane distillation tower lightness removal device has a serious problem of steam and cooling water energy waste corresponding to the heating process and condensation process, resulting in high trichlorosilane production costs and not in line with the environmental protection concept of energy conservation and emission reduction. Therefore, corresponding technical improvements and optimization are urgently needed. Utility Model Content

[0003] In view of the above situation, the utility model provides a trichlorosilane distillation tower lightness removal device, which can effectively reduce the steam and cooling water energy consumption in the distillation process and save the trichlorosilane production cost.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A light removal device for a trichlorosilane distillation tower comprises a light removal tower, wherein a distillation chamber is arranged at the lower part of the light removal tower, a light removal chamber is arranged at the upper part, a funnel-shaped collecting tank is arranged between the distillation chamber and the light removal chamber, and the edge of the collecting tank is fixedly connected to the inner wall of the light removal tower through an annular shutter.

[0006] The coaxial sleeve on the outer side of the bottom of the distillation chamber is provided with a steam jacket for heating the trichlorosilane feed liquid. The inner side of the bottom of the light removal chamber is provided with a heat exchange coil, and the waste heat of the evaporated trichlorosilane gas is used to preliminarily preheat the incoming trichlorosilane feed liquid, which helps to reduce the heating burden of the steam jacket and save steam consumption. At the same time, the trichlorosilane feed liquid is used to preliminarily cool the evaporated trichlorosilane gas, which helps to reduce the cooling burden of the condenser and save cooling water consumption.

[0007] A liquid return pipe is connected to the bottom of the collecting tank, and a feed port, a liquid return port and a gas extraction port are arranged on the side wall of the distillation chamber. The feed port is connected to the liquid outlet end of the heat exchange coil, and the liquid inlet end of the heat exchange coil is connected to the feed pipe. A feed valve is arranged on the feed pipe for controlling the feed of trichlorosilane to be distilled.

[0008] The vacuum port is externally connected to a vacuum pump, which can create a certain negative pressure in the light removal tower by vacuuming, which is beneficial to the accelerated evaporation of trichlorosilane after feeding. A drain pipe is provided at the bottom of the distillation chamber, and a drain valve is installed on the drain pipe to control the discharge of the separated liquid.

[0009] A reboiler is arranged outside the light removal tower, the liquid inlet of the reboiler is connected to the liquid return pipe of the collecting tank through a reflux pump, and the liquid outlet of the reboiler is connected to the liquid return port, which is used to condense the trichlorosilane vapor collected in the collecting tank on the heat exchange coil and send the trichlorosilane liquid dripping back to the distillation chamber for further distillation.

[0010] A condenser and a liquid storage tank are also provided on the outside of the lightness removal tower. The air inlet of the condenser is connected to the air outlet at the top of the lightness removal tower, and the liquid outlet of the condenser is connected to the liquid inlet of the liquid storage tank. A discharge pipe is provided at the bottom of the liquid storage tank, and a discharge valve is installed on the discharge pipe to control the discharge of trichlorosilane after purification. A return pipe is also provided on the liquid storage tank, and the return pipe is connected to the feed pipe through a circulation pump and a return valve. Combined with the feed valve, switching control between direct feeding of trichlorosilane and return feeding from the liquid storage tank can be realized.

[0011] Furthermore, three layers of swirl plates are arranged in the de-lightening chamber at equal intervals from bottom to top, and a first packing layer, a second packing layer and a third packing layer are arranged above the three layers of swirl plates respectively.

[0012] Furthermore, the first packing layer, the second packing layer and the third packing layer are respectively filled with PP multi-faceted hollow ball packing, ceramic step ring packing and stainless steel saddle ring packing, so as to increase the contact area between trichlorosilane gas and the packing.

[0013] Furthermore, a steam inlet and a steam outlet are provided on the side wall of the steam jacket for heating and distilling the trichlorosilane liquid in the distillation chamber.

[0014] The reboiler and the condenser are both shell and tube heat exchangers, and the reboiler is also provided with a second steam inlet and a second steam outlet, and the second steam inlet is connected to the first steam outlet of the steam jacket. The condenser is also provided with a cooling water inlet and a cooling water outlet.

[0015] The utility model also includes other components that enable it to be used normally, which are all conventional means in the field. In addition, devices or components not limited in the utility model, such as: lightness removal tower, cyclone plate, heat exchange coil, shell and tube heat exchanger, liquid storage tank and various pipeline valves, etc., all adopt the existing technology in the field.

[0016] The beneficial effects of the utility model are as follows:

[0017] The utility model provides a light removal device for a trichlorosilane distillation tower. By adding a heat exchange coil inside the light removal tower, the waste heat of the trichlorosilane distillation gas is recovered for preheating the trichlorosilane feed. Meanwhile, the trichlorosilane feed liquid with a relatively low temperature is used to preliminarily cool the trichlorosilane evaporation gas, which is beneficial to saving the heating steam consumption of the distillation chamber and the cooling water consumption of the condenser, thus achieving two goals at one stroke. Moreover, by adding a vacuum pump, the evaporation of the feed liquid is accelerated, which is also beneficial to reducing the consumption of the heating steam for the feed liquid. In addition, by means of a reflux pump and a circulation pump, the return circulation distillation of the trichlorosilane feed liquid can be realized, which is beneficial to improving the purification efficiency of the trichlorosilane and the purity of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the light removal device of the trichlorosilane distillation tower in the embodiment. DETAILED DESCRIPTION

[0019] The technical solution of the present utility model will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments.

[0020] Example

[0021] like Figure 1 As shown, a light removal device for a trichlorosilane distillation tower comprises a light removal tower, wherein a distillation chamber 1 is arranged at the lower part of the light removal tower, a light removal chamber 2 is arranged at the upper part, a funnel-shaped collecting tank 3 is arranged between the distillation chamber and the light removal chamber, the edge of the collecting tank is fixedly connected to the inner wall of the light removal tower through an annular shutter 4, and the distillation chamber and the light removal chamber can be ventilated up and down.

[0022] A steam jacket 5 is provided on the outer coaxial sleeve at the bottom of the distillation chamber for heating the trichlorosilane liquid. A heat exchange coil 6 is provided on the inner side of the bottom of the light removal chamber for preliminarily preheating the incoming trichlorosilane liquid by utilizing the waste heat of the evaporated trichlorosilane gas, which helps to reduce the heating burden of the steam jacket and save steam consumption. At the same time, the evaporated trichlorosilane gas is preliminarily cooled by utilizing the trichlorosilane liquid, which helps to reduce the cooling burden of the condenser and save cooling water consumption.

[0023] A liquid return pipe 7 is connected to the bottom of the collecting tank, and a feed port 8, a liquid return port 9 and a gas extraction port 10 are arranged on the side wall of the distillation chamber. The feed port is connected to the liquid outlet end of the heat exchange coil, and the liquid inlet end of the heat exchange coil is connected to the feed pipe. A feed valve is arranged on the feed pipe for controlling the feed of trichlorosilane to be distilled.

[0024] The vacuum port is externally connected to a vacuum pump 11. Before feeding the light-removal tower, the interior of the distillation chamber is first evacuated by the vacuum pump to make the interior of the light-removal tower in a certain negative pressure state, which is conducive to the accelerated evaporation of trichlorosilane after feeding. A drain pipe 12 is provided at the bottom of the distillation chamber, and a drain valve is installed on the drain pipe to control the discharge of the separated heavy liquid components of silicon tetrachloride.

[0025] A reboiler 13 is arranged outside the light removal tower, the liquid inlet of the reboiler is connected to the liquid return pipe of the collecting tank through a reflux pump 14, and the liquid outlet of the reboiler is connected to the liquid return port to collect trichlorosilane liquid and send it back to the distillation chamber for further distillation.

[0026] A condenser 15 and a liquid storage tank 16 are also provided on the outside of the lightness removal tower. The air inlet of the condenser is connected to the air outlet 17 at the top of the lightness removal tower, and the liquid outlet of the condenser is connected to the liquid inlet 18 of the liquid storage tank. A discharge pipe 19 is provided at the bottom of the liquid storage tank. A discharge valve is installed on the discharge pipe to control the discharge of trichlorosilane after purification. A return pipe is also provided on the liquid storage tank. The return pipe is connected to the feed pipe through a circulation pump 20 and a return valve. Combined with the feed valve, switching control between direct feeding of trichlorosilane and return feeding from the liquid storage tank can be achieved.

[0027] When it is detected that the purity of the trichlorosilane product in the liquid storage tank does not meet the standard or the required purity standard of the trichlorosilane product is increased, the trichlorosilane product in the liquid storage tank can be returned to the lightness removal tower for further distillation and purification.

[0028] The de-lightening chamber is provided with three layers of cyclone plates 21 at equal intervals from bottom to top, and the first packing layer, the second packing layer and the third packing layer are respectively provided above the three layers of cyclone plates. An inspection port 22 is also provided at the top of the de-lightening tower, and a manhole cover is provided on the inspection port.

[0029] The first packing layer, the second packing layer and the third packing layer are respectively filled with PP polyhedral hollow ball packing 23, ceramic step ring packing 24 and stainless steel saddle ring packing 25. The lightness removal tower packing can increase the contact area between the trichlorosilane gas and the packing, and can react or adsorb other components doped in the trichlorosilane gas to improve the distillation purity of the trichlorosilane.

[0030] The three types of fillers each have their own advantages and disadvantages. Stainless steel metal fillers have high strength and good corrosion resistance, but are more expensive; ceramic fillers have good temperature resistance and corrosion resistance, but are fragile; plastic fillers are easy to manufacture and cheap, but not strong enough.

[0031] The side wall of the steam jacket is provided with a steam inlet 26 and a steam outlet 27, which are used for heating and distilling the trichlorosilane liquid in the distillation chamber. The steam jacket is also provided with a steam outlet 3 28, on which a steam control valve is installed. The steam inlet 1, steam outlet 2 and steam outlet 3 are all circulated and connected to the existing steam network of the trichlorosilane production system.

[0032] The reboiler and condenser are both shell and tube heat exchangers. The reboiler is also provided with a second steam inlet 29 and a second steam outlet 30, and the second steam inlet is connected to the first steam outlet of the steam jacket. The condenser is also provided with a cooling water inlet 31 and a cooling water outlet 32. The cooling water inlet and the cooling water outlet are circulated and externally connected to the existing cooling water network of the trichlorosilane production system.

[0033] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Without departing from the scope and spirit of the described embodiments, many modifications and changes are obvious to ordinary technicians in this technical field. Any technical deformation made within the spirit and principles of the present invention falls within the protection scope of the present invention.

Claims

1. A trichlorosilane distillation tower light removal device, comprising a light removal tower, characterized in that: The light removal tower is provided with a distillation chamber at the bottom, a light removal chamber at the top, a funnel-shaped collecting tank is provided between the distillation chamber and the light removal chamber, the edge of the collecting tank is fixedly connected to the inner wall of the light removal tower through an annular shutter, a steam jacket is provided on the outer coaxial sleeve of the bottom of the distillation chamber, a heat exchange coil is provided on the inner side of the bottom of the light removal chamber, a liquid return pipe is connected to the bottom of the collecting tank, a feed port, a liquid return port and an air pump are provided on the side wall of the distillation chamber, the feed port is connected to the liquid outlet end of the heat exchange coil, the liquid inlet end of the heat exchange coil is connected to the feed pipe, a feed valve is provided on the feed pipe for controlling the feeding of trichlorosilane to be distilled, the air pump is externally connected to a vacuum pump, and the distillation A drain pipe is provided at the bottom of the distillation chamber, and a drain valve is installed on the drain pipe. A reboiler is provided on the outside of the light-removing tower. The liquid inlet of the reboiler is connected to the return pipe of the collecting tank through a reflux pump, and the liquid outlet of the reboiler is connected to the return port. A condenser and a liquid storage tank are also provided on the outside of the light-removing tower. The air inlet of the condenser is connected to the air outlet at the top of the light-removing tower, and the liquid outlet of the condenser is connected to the liquid inlet of the liquid storage tank. A discharge pipe is provided at the bottom of the liquid storage tank, and a discharge valve is installed on the discharge pipe for controlling the discharge of trichlorosilane after purification. A return pipe is also provided on the liquid storage tank, and the return pipe is connected to the feed pipe through a circulation pump and a return valve.

2. A trichlorosilane distillation tower light removal device according to claim 1, characterized in that: The de-lightening chamber is provided with three layers of swirl plates at equal intervals from bottom to top, and a first packing layer, a second packing layer and a third packing layer are respectively provided above the three layers of swirl plates.

3. A trichlorosilane distillation tower light removal device according to claim 2, characterized in that: The first packing layer, the second packing layer and the third packing layer are filled with PP multi-faceted hollow ball packing, ceramic step ring packing and stainless steel saddle ring packing respectively.

4. A trichlorosilane distillation tower light removal device according to claim 1, characterized in that: A steam inlet 1 and a steam outlet 1 are arranged on the side wall of the steam jacket, and a steam inlet 2 and a steam outlet 2 are also arranged on the reboiler, and the steam inlet 2 is connected to the steam outlet 1 of the steam jacket.

5. A trichlorosilane distillation tower light removal device according to claim 4, characterized in that: The reboiler and the condenser are both shell and tube heat exchangers, and the condenser is also provided with a cooling water inlet and a cooling water outlet.

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