Tail gas recycling device for preparing silicate ester from silicon powder through one-step method

Abstract

The tail gas recycling device comprises an alcohol washing tower and a water washing tower, the top of the alcohol washing tower is communicated with the side wall of the lower end of the water washing tower through a pipeline, and the bottom of the alcohol washing tower is communicated with a feeding port of a sol preparation kettle through a pipeline. A discharge hole of the sol preparation kettle is communicated with the sol storage tank through a pipeline; the side wall of the lower end of the alcohol washing tower is communicated with a tail gas feeding pipe; a tail gas recovery pipe is arranged at the top of the water washing tower; and the liquid in each pipeline is conveyed through a pump. According to the utility model, the alcohol washing tower and the water washing tower are combined, so that the tail gas generated by producing silicate ester from silicon powder through a one-step method is purified, and the problems that part of uncondensed products enter the atmosphere along with hydrogen, the environment is polluted and the utilization rate of the products is reduced in the production process of the silicate ester are avoided; meanwhile, the sol preparation kettle and the sol storage tank are combined, so that effective recycling of silicate ester is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of tail gas recovery, in particular to a tail gas recovery and utilization device used for preparing silicate from silicon powder in a one-step process. Background Art

[0002] Silicates are an important class of compounds that can be used to prepare heat-resistant and chemical-resistant coatings and silicone solvents. They can also be used as insulating materials in the electronics industry, optical glass treating agents, adhesives, and in the synthesis of silicones.

[0003] Currently, the main methods for scaling up orthosilicate production in China are the one-step silicon powder process and the silicon tetrachloride process. Compared to the silicon tetrachloride process, the one-step silicon powder process does not involve chlorine, produces no corrosive gases, and has lower requirements for equipment materials. It is more environmentally friendly, cleaner, and has simpler process steps.

[0004] However, the one-step silicate production process from silicon powder generates hydrogen, a non-condensable gas. During the exhaust process, hydrogen carries the product into the atmosphere, reducing product yield and potentially polluting the environment. Furthermore, since the reaction temperature is typically close to or even several times higher than the boiling point of the product, the condensation system must meet high requirements to minimize the amount of product entering the atmosphere along with the hydrogen. To prevent the reaction rate from being too high, which can cause some product to remain uncondensed during the condensation process and enter the atmosphere along with the hydrogen, polluting the environment and reducing product utilization, a tail gas recovery and utilization device is needed to address this issue. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a tail gas recovery and utilization device for preparing silicate esters from silicon powder in a one-step process, so as to avoid the problem that some uncondensed products enter the atmosphere along with hydrogen during the silicate production process, polluting the environment and reducing product utilization.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A tail gas recovery and utilization device for preparing silicate esters from silicon powder in a one-step process comprises an alcohol scrubbing tower and a water scrubbing tower, wherein the lower end side wall of the alcohol scrubbing tower is connected to a tail gas feed pipe; the alcohol scrubbing tower is filled with alcohol washing liquid to dissolve alcohol and silicate ester in the tail gas entering the alcohol scrubbing tower; the top of the alcohol scrubbing tower is connected to the side wall of the lower end of the water scrubbing tower through a pipeline, and the water scrubbing tower is filled with water washing liquid to wash the gas entering the water scrubbing tower; the top of the water scrubbing tower is provided with a tail gas recovery pipe; the bottom of the alcohol scrubbing tower is connected to the feed port of a sol preparation kettle through a pipeline, and the discharge port of the sol preparation kettle is connected to a sol storage tank through a pipeline; the liquid in each pipeline is transported by a pump.

[0008] Furthermore, an air inlet branch pipe is provided on the pipeline connecting the alcohol scrubber and the water scrubber, so as to introduce inert gas into the water scrubber through the air inlet branch pipe.

[0009] Furthermore, a packing support plate is horizontally arranged at the upper end of the interior of the alcohol washing tower, and the packing support plate is densely covered with ventilation holes; the cross-sectional area of ​​the packing support plate is the same as the cross-sectional area of ​​the interior of the alcohol washing tower.

[0010] Furthermore, a plurality of steel balls are laid flat on the filler support plate.

[0011] Furthermore, a circulation branch pipe is provided on the pipeline connecting the alcohol washing tower and the sol preparation kettle, the end of the circulation branch pipe extends into the alcohol washing tower and is located above the steel ball, and a spray device is provided at the end of the circulation branch pipe.

[0012] Furthermore, the bottom of the water washing tower is connected to the side wall of the upper end of the water washing tower through a reflux pipe, and a reflux pump is provided on the reflux pipe.

[0013] Furthermore, the exhaust port at the top of the sol preparation kettle is connected to the feed port of the condenser through a pipe, the discharge port of the condenser is connected to the lower end side wall of the reflux tank through a pipe, and the top of the reflux tank is connected to the side wall of the lower end of the alcohol washing tower through a pipe; the bottom of the reflux tank is connected to the feed port of the sol preparation kettle and the top of the alcohol washing tower through pipes respectively.

[0014] Furthermore, the flat thickness of the steel balls is one-sixth to one-fifth of the height of the alcohol washing tower.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The utility model realizes the purification treatment of the tail gas generated by the one-step production of silicate from silicon powder through the combination of an alcohol washing tower and a water washing tower, thereby avoiding the problem that part of the uncondensed product enters the atmosphere with hydrogen during the production of silicate, polluting the environment and reducing the product utilization rate; at the same time, the combination of a sol preparation kettle and a sol storage tank realizes the effective recycling of silicate.

[0017] 2. The tail gas feed pipe of the utility model is arranged on the alcohol washing tower. The tail gas first passes through the alcohol washing tower and then passes through the water washing tower. This avoids a certain amount of silicate being hydrolyzed in the water system, resulting in a low silicate utilization rate.

[0018] 3. The use of the device of the utility model to recover and treat the tail gas also reduces the load on the condensation system for producing silicate esters by the one-step method of silicon powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a tail gas recovery and utilization device for preparing silicate from silicon powder in a one-step process according to the present invention.

[0020] In the figure, there are alcohol washing tower 1, water washing tower 2, sol preparation kettle 3, sol storage tank 4, tail gas feed pipe 5, tail gas recovery pipe 6, air intake branch pipe 7, packing support plate 8, steel wool 9, circulation branch pipe 10, reflux pipe 11, condenser 12, and reflux tank 13. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the embodiments.

[0022] like Figure 1 As shown, the utility model provides a tail gas recovery and utilization device for preparing silicate from silicon powder in one step, comprising an alcohol washing tower 1 and a water washing tower 2, wherein the lower end side wall of the alcohol washing tower 1 is connected with a tail gas feed pipe 5; the alcohol washing tower 1 is filled with alcohol washing liquid to dissolve the alcohol and silicate in the tail gas entering the alcohol washing tower 1; the top of the alcohol washing tower 1 is connected to the side wall of the lower end of the water washing tower 2 through a pipeline, and the water washing tower 2 is filled with water washing liquid to wash the gas entering the water washing tower 2; the top of the water washing tower 2 is provided with a tail gas recovery pipe 6; the bottom of the alcohol washing tower 1 is connected to the feed port of the sol preparation kettle 3 through a pipeline, and the discharge port of the sol preparation kettle 3 is connected to the sol storage tank 4 through a pipeline; the liquid in each pipeline is transported by a pump.

[0023] Working principle: The tail gas generated by the one-step method of silicon powder contains alcohol, silicate and hydrogen. When the tail gas is recycled, the tail gas first enters the alcohol scrubber 1 from the tail gas feed pipe 5. The silicate and alcohol in the tail gas will be dissolved in the alcohol in the alcohol scrubber 1. The remaining hydrogen and a small amount of undissolved silicate flow through the pipe at the top of the alcohol scrubber 1 into the water scrubber 2 for further recovery. A small amount of undissolved silicate dissolves in water, and the remaining hydrogen is recycled or discharged through the tail gas recovery pipe 6. The silicate left in the alcohol scrubber 1 flows into the sol preparation kettle 3 through the pipe and is used for the preparation of silica sol. The prepared silica sol is transported to the sol storage tank 4 through a pipe for storage, thereby realizing the effective utilization of silicate. Among them, during water washing, the pH of the water scrubber 2 is 5~6, which ensures that a small amount of silicate will not be condensed in the water scrubber 2, the gas can pass through, and there is no pressure buildup in the system.

[0024] In practice, an air inlet branch pipe 7 is provided on the pipeline connecting the alcohol scrubber 1 and the water scrubber 2 to introduce inert gas into the water scrubber 2. The introduced inert gas can dilute the hydrogen to prevent excessive hydrogen concentration and increase the risk of explosion; and can also discharge oxygen in the pipeline to further prevent hydrogen explosion.

[0025] In practice, a packing support plate 8 is horizontally disposed at the upper end of the alcohol scrubber 1. The packing support plate 8 is densely covered with vents. The cross-sectional area of ​​the packing support plate 8 is the same as the cross-sectional area of ​​the interior of the alcohol scrubber 1. Thus, different packing materials can be placed inside the alcohol scrubber 1 via the packing support plate 8 to further treat the exhaust gas.

[0026] In practice, several steel balls 9 are laid flat on the packing support plate 8. Steel balls 9 have a porous structure, which effectively adsorbs silicates that are not absorbed by the alcohol, thereby further purifying the hydrogen. Furthermore, the steel balls 9 are relatively low in cost, which helps reduce costs and increase efficiency.

[0027] In a specific implementation, a circulation branch pipe 10 is provided on the pipeline connecting the alcohol washing tower 1 and the sol preparation kettle 3. The end of the circulation branch pipe 10 extends into the alcohol washing tower 1 and is located above the steel wool 9. A spray device is provided at the end of the circulation branch pipe 10. Through the circulating flushing of the alcohol liquid, the silicate esters in the hydrogen gas that are not absorbed by the alcohol can be further absorbed. Secondly, the silicate esters adsorbed on the steel wool 9 can be flushed into the alcohol washing liquid below, thereby facilitating the recovery and utilization of the silicate esters.

[0028] In practice, the bottom of the water scrubber 2 is connected to the sidewall of the upper end of the water scrubber 2 via a reflux pipe 11, and a reflux pump is provided on the reflux pipe 11. The circulating water scrubber further absorbs silicates in the hydrogen that have not been absorbed by the alcohol. This not only purifies the hydrogen, but also improves the recovery rate of the silicates.

[0029] In a specific implementation, the exhaust port at the top of the sol preparation kettle 3 is connected to the feed port of the condenser 12 via a pipe, the discharge port of the condenser 12 is connected to the lower side wall of the reflux tank 13 via a pipe, and the top of the reflux tank 13 is connected to the lower side wall of the alcohol washing tower 1 via a pipe; the bottom of the reflux tank 13 is connected to the feed port of the sol preparation kettle 3 and the top of the alcohol washing tower 1 via pipes. In this way, the alcohol evaporated from the reaction system can be recycled and reused through the condenser 12, the reflux tank 13 and the corresponding pipes, which not only improves the utilization rate of the alcohol, but also prevents the alcohol liquid from being directly discharged into the air and polluting the air.

[0030] In a specific implementation, the flat thickness of the steel balls 9 is one-sixth to one-fifth of the height of the alcohol washing tower 1 .

[0031] In specific implementation, since the washing liquid in the water washing tower 2 contains a small amount of silicate, the washing liquid in the water washing tower 2 can be used to prepare the acid catalyst for the aerogel, thereby achieving recycling and being more environmentally friendly.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Ordinary technicians in this field should understand that those modifications or equivalent replacements of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A tail gas recovery and utilization device for preparing silicate esters from silicon powder in one step, characterized in that: It includes an alcohol washing tower and a water washing tower, and the lower end side wall of the alcohol washing tower is connected to a tail gas feed pipe; the alcohol washing tower is filled with alcohol washing liquid to dissolve the alcohol and silicate in the tail gas entering the alcohol washing tower; the top of the alcohol washing tower is connected to the side wall of the lower end of the water washing tower through a pipeline, and the water washing tower is filled with water washing liquid to wash the gas entering the water washing tower; the top of the water washing tower is provided with a tail gas recovery pipe; the bottom of the alcohol washing tower is connected to the feed port of the sol preparation kettle through a pipeline, and the discharge port of the sol preparation kettle is connected to the sol storage tank through a pipeline; the liquid in each pipeline is transported by a pump.

2. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 1, characterized in that: An air inlet branch pipe is provided on the pipeline connecting the alcohol scrubber and the water scrubber, so as to introduce inert gas into the water scrubber through the air inlet branch pipe.

3. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 1, characterized in that: A packing support plate is horizontally arranged at the upper end of the interior of the alcohol washing tower, and the packing support plate is densely covered with ventilation holes; the cross-sectional area of ​​the packing support plate is the same as the cross-sectional area of ​​the interior of the alcohol washing tower.

4. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 3, characterized in that: A plurality of steel balls are laid flat on the filler support plate.

5. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 4, characterized in that: A circulation branch pipe is provided on the pipeline connecting the alcohol washing tower and the sol preparation kettle. The end of the circulation branch pipe extends into the alcohol washing tower and is located above the steel ball. A spray device is provided at the end of the circulation branch pipe.

6. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 1, characterized in that: The bottom of the water washing tower is connected to the side wall of the upper end of the water washing tower through a reflux pipe, and a reflux pump is provided on the reflux pipe.

7. The tail gas recovery and utilization device for preparing silicate by one-step method using silicon powder according to claim 1, characterized in that: The exhaust port at the top of the sol preparation kettle is connected to the feed port of the condenser through a pipe, the discharge port of the condenser is connected to the lower end side wall of the reflux tank through a pipe, and the top of the reflux tank is connected to the side wall of the lower end of the alcohol washing tower through a pipe; the bottom of the reflux tank is connected to the feed port of the sol preparation kettle and the top of the alcohol washing tower through pipes.

8. The tail gas recovery and utilization device for preparing silicate ester by one-step method using silicon powder according to claim 3, characterized in that: The flat thickness of the steel balls is one-sixth to one-fifth of the height of the alcohol washing tower.

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