阅读说明：本技术 用于有机硅、多晶硅生产系统湿式除尘的改进方法及装置 (Improved method and device for wet dust removal of organic silicon and polycrystalline silicon production system ) 是由 尚剑 陈维平 李佳 王书明 王永东 洪钟 董文胜 骆彩萍 于 2021-07-30 设计创作，主要内容包括：本发明公开了一种用于有机硅、多晶硅生产系统湿式除尘的改进方法及装置。该方法包括以下步骤：首先将经过干式除尘后,还含有少量＜10μm的细硅粉与催化剂颗粒的反应气送入到湿式除尘器中,经湿式除尘后的反应气再送入到洗涤塔中进行洗涤、降温。其洗涤液可用洗涤塔塔釜的高沸物或洗涤塔的塔顶冷凝液；除尘后含细硅粉等固体颗粒的洗涤液进入到洗涤液回收罐处,加热蒸发回收其中的液相物料。通过该方法,可以有效降低进入洗涤塔中的反应气的固体颗粒含量,减轻洗涤塔中堵塞情况的发生,减轻现场操作强度,并实现清洁生产；同时,也可减少附加值低的高沸渣浆产量,更充分回收其中的可利用产品。(The invention discloses an improved method and device for wet dust removal of an organic silicon and polycrystalline silicon production system. The method comprises the following steps: firstly, the reaction gas which is subjected to dry dust removal and also contains a small amount of fine silicon powder with the particle size of less than 10 mu m and catalyst particles is sent into a wet dust remover, and the reaction gas subjected to wet dust removal is sent into a washing tower for washing and cooling. The washing liquid can be high-boiling-point substances at the tower bottom of the washing tower or tower top condensate of the washing tower; and (4) after dust removal, the washing liquid containing solid particles such as fine silicon powder enters a washing liquid recovery tank, and the liquid-phase material in the washing liquid is heated, evaporated and recovered. By the method, the solid particle content of the reaction gas entering the washing tower can be effectively reduced, the occurrence of blockage in the washing tower is reduced, the field operation intensity is reduced, and clean production is realized; meanwhile, the yield of the high-boiling residue slurry with low additional value can be reduced, and the available products in the high-boiling residue slurry can be more fully recovered.)

1. An improved device for wet dust removal of an organic silicon and polycrystalline silicon production system is characterized by comprising the following equipment: a washing dust remover, a washing liquid recovery tank, a washing tower reboiler, a washing tower condenser and a washing liquid delivery pump; the washing dust remover and the gas phase inlet of the washing liquid are connected with the gas phase outlet after dry dust removal, and the gas phase outlet of the washing dust remover is connected with the gas phase inlet of the washing tower; the liquid phase inlet of the washing dust remover is connected with the tower kettle of the washing tower, the liquid phase outlet of the washing dust remover is connected with the inlet of the washing liquid recovery tank, and the washing liquid recovery tank is provided with an indirect heating component.

2. An improved method for wet dust removal of an organic silicon and polycrystalline silicon production system is characterized by utilizing the improved device of claim 1, and comprises the following steps: firstly, introducing reaction gas containing silicon powder and catalyst particles which are less than 10 mu m after dry dust removal into a washing dust remover, and then sending the reaction gas after washing dust removal into a washing tower for further washing and high-boiling-point substance pre-separation; the washing liquid used by the washing dust remover is high-boiling-point substances in a tower kettle of the washing tower, the washing liquid containing fine silicon powder obtained after washing and dust removal is sent into a washing liquid recovery tank, and the washing liquid recovery tank evaporates liquid-phase products contained in the washing liquid into gas phase and sends the gas phase back to the washing system.

3. The improved wet dedusting method for organosilicon and polysilicon production system as recited in claim 2, characterized in that the gas phase temperature in the scrubber is controlled at 180-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-65 ℃; the temperature of a reboiler of the tower kettle is controlled to be 120-440 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 440 ℃.

4. The improved wet dedusting process for organosilicon and polysilicon producing system as recited in claim 2, wherein silicon powder smaller than 10 μm is eliminated in the washing deduster, the tower bottom of the washing tower is liquid high boiling residue with solid powder impurity content less than 3%, and the high boiling residue slurry is extracted from the washing liquid recovering tank only.

5. An improved device for wet dust removal of an organic silicon and polycrystalline silicon production system is characterized by comprising the following equipment: a washing dust remover, a washing liquid recovery tank, a washing tower reboiler, a washing tower condenser and a washing liquid delivery pump; the washing dust remover and the gas phase inlet of the washing liquid are connected with the gas phase outlet after dry dust removal, and the gas phase outlet of the washing dust remover is connected with the gas phase inlet of the washing tower; the liquid phase inlet of the washing dust remover is not connected with the tower kettle of the washing tower any more, but is connected with the condenser of the washing tower through a delivery pump, so that the washing dust remover can use the condensed liquid at the top of the washing tower as the washing liquid.

6. An improved method for wet dust removal of an organic silicon and polycrystalline silicon production system is characterized by utilizing the improved device of claim 5, and comprises the following steps: firstly, introducing reaction gas containing silicon powder and catalyst particles which are less than 10 mu m after dry dust removal into a washing dust remover, and then sending the reaction gas after washing dust removal into a washing tower for further washing and high-boiling-point substance pre-separation; the washing liquid used by the washing dust remover is condensed liquid at the top of the washing tower, and the washing liquid containing fine silicon powder obtained after washing and dust removal is sent into a washing liquid recovery tank, reheated and evaporated, and sent back to the washing system.

7. The improved wet dedusting method for organosilicon and polysilicon production system as recited in claim 6, wherein the gas phase temperature in the scrubber is controlled at 150-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-95 ℃; controlling the temperature of a reboiler at the tower kettle to be 120-410 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 410 ℃.

8. The improved wet dust collector for organosilicon and polysilicon production system as claimed in claim 1, wherein the indirect heating component is heated indirectly by electric heating or heating medium, the heating medium is heat conducting oil, high temperature steam or other high temperature medium, and the temperature is controlled at 180-460 ℃.

9. An improved apparatus for wet dedusting of organosilicon and polysilicon production system as recited in claim 1 or 5, wherein the scrubber is a spray scrubber, a cyclone scrubber, a bubble scrubber or other wet scrubber which is not easy to be blocked by scale.

10. The improved wet dust removal device for the organosilicon and polysilicon production system as claimed in claim 9, wherein the spray scrubber, cyclone scrubber or bubble scrubber are used alone or any two of them are used in series; the washing and dust removing mode is as follows: spraying first and then whirlwind, or whirlwind first and then spraying.

Technical Field

The invention relates to a dust removal system and a treatment method, in particular to an improved method and a device for wet dust removal of an organic silicon and polycrystalline silicon production system.

Background

In the production system of organosilicon and polysilicon, the reaction gas generated from the fluidized bed reactor often has a part of solid silicon powder or catalyst particles entrained. In order to recover the raw materials and prevent fine silicon powder from entering a subsequent separation unit as much as possible to block equipment and influence normal production of a factory, the method is generally adopted in industry that reaction gas containing solid dust is subjected to dry dust removal by a multi-stage cyclone separator and then is sent into a washing tower for wet washing. The flow process indeed remarkably avoids the situation that the subsequent separation unit is blocked by the accumulated silicon powder; but the method is limited in that the dry dedusting is difficult to effectively remove the dust of particles less than 10 mu m, and the washing tower is difficult to avoid dust accumulation and blockage after running for a period of time, so that the washing efficiency is influenced; even parking for cleaning in severe cases; this presents a great challenge to the continuous and stable operation of organosilicon and polysilicon devices, which makes the field operation intensity higher and difficult to realize clean production. In addition, the heating effect of the tower kettle of the washing tower is not ideal, so that the yield of high-boiling residue slurry with low additional value is large, and the available products cannot be fully recovered.

In order to solve the problem, patent CN 108434910 a proposes to add a precision filter with a filter element in the dry dust removal step to filter fine dust, and to increase the filter operation time by adding a methyl chloride gas blowback device. \\20319Bec 'dust removal separation equipment in an organic silicon device' proposes to add a bubble washing dust remover to carry out wet dust removal in the wet dust removal process so as to ensure the dust removal efficiency, but the optimization only aims at the dust removal process, and the influence and the improvement on the subsequent process and equipment are not considered on the source and the recycling scheme of the washing liquid.

Disclosure of Invention

The invention provides an improved wet dust removal method and device used in the dust removal process of organosilicon and polysilicon production. By additionally arranging the cyclone washing dust remover and selecting a proper washing liquid and a recovery scheme, the waste of recoverable products is avoided to the maximum extent while the washing efficiency of the fine silicon powder is improved, the dust removal effect is obviously improved, and the yield of the high-boiling residue slurry with low added value is obviously reduced.

One of the purposes of the invention is to provide an improved device for wet dust removal of an organic silicon and polycrystalline silicon production system, which is characterized by comprising the following equipment: a washing dust remover, a washing liquid recovery tank, a washing tower reboiler, a washing tower condenser and a washing liquid delivery pump; the washing dust remover and the gas phase inlet of the washing liquid are connected with the gas phase outlet after dry dust removal, and the gas phase outlet of the washing dust remover is connected with the gas phase inlet of the washing tower; the liquid phase inlet of the washing dust remover is connected with the tower kettle of the washing tower, the liquid phase outlet of the washing dust remover is connected with the inlet of the washing liquid recovery tank, and the washing liquid recovery tank is provided with an indirect heating component.

The invention also aims to provide an improved wet dust removal method for an organic silicon and polycrystalline silicon production system, which is characterized by comprising the following steps: firstly, introducing reaction gas containing silicon powder and catalyst particles which are less than 10 mu m after dry dust removal into a washing dust remover, and then sending the reaction gas after washing dust removal into a washing tower for further washing and high-boiling-point substance pre-separation; the washing liquid used by the washing dust remover is high-boiling-point substances in the tower kettle of the washing tower, and the washing liquid containing the fine silicon powder after washing and dust removal is sent into a washing liquid recovery tank, heated and evaporated, and the liquid phase is sent back to the washing system.

Further, the gas phase temperature in the washing dust remover is controlled to be 180-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-65 ℃; the temperature of a reboiler of the tower kettle is controlled to be 120-440 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 440 ℃.

Further, silicon powder with the particle size of less than 10 microns is removed in a washing dust remover, liquid high-boiling-point substances with the solid powder impurity content of less than 3 percent are arranged at the tower bottom of a washing tower, and high-boiling-point slag slurry is only extracted from a washing liquid recovery tank.

The invention also aims to provide another improved device for wet dust removal of an organic silicon and polycrystalline silicon production system, which is characterized in that a liquid phase inlet of a washing dust remover is not connected with a tower kettle of a washing tower any more, but is connected with a condenser of the washing tower through a conveying pump. So that the washing dust remover can use the condensate at the top of the washing tower as the washing liquid.

The invention aims at providing another improved method for wet dust removal of an organic silicon and polysilicon production system, which is characterized in that a washing liquid used by a washing dust remover is a tower top condensate of a washing tower, the washing liquid containing fine silicon powder obtained after washing and dust removal is sent into a washing liquid recovery tank, and a liquid phase product in the washing liquid is evaporated again and sent back to the washing system.

Further, the gas phase temperature in the washing dust remover is controlled to be 150-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-95 ℃; controlling the temperature of a reboiler at the tower kettle to be 120-410 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 410 ℃.

Furthermore, the indirect heating component adopts an electric heating mode or indirect heating by a heating medium, the heating medium is heat conduction oil, high-temperature steam or other high-temperature media, and the temperature is controlled to be 180-460 ℃.

Further, the scrubbing dust collector can be a wet dust collector which is not easy to scale and block, such as a spray scrubbing dust collector, a cyclone scrubbing dust collector, a bubbling scrubbing dust collector and the like, and preferably is a cyclone scrubbing dust collector.

Furthermore, a spray washing dust remover, a cyclone washing dust remover or a bubbling washing dust remover are used independently, or any two of the spray washing dust remover, the cyclone washing dust remover or the bubbling washing dust remover are used in series; the washing and dust removing mode is as follows: spraying first and then whirlwind, or whirlwind first and then spraying.

The invention has the beneficial effects that:

1. the washing dust remover in front of the washing tower is added in the wet dust removal, and a large amount of fine silicon powder possibly causing dust accumulation and blockage of the washing tower can be filtered out in the washing dust remover due to the liquid film adsorption effect, so that the production device is prevented from stopping due to blockage of the washing tower, and the running stability of the device is improved.

2. Because the content of the fine silicon powder in the reaction gas entering the washing tower is obviously reduced, the product at the tower bottom is a high-boiling residue which can be cracked and recovered, and the high-boiling residue slurry is only generated in the washing liquid recovery tank, thereby greatly reducing the residue slurry yield with low added value and improving the output value of the whole production system.

In conclusion, the wet dust removal device has the characteristics of stability, simplicity, environmental protection and energy conservation, is suitable for wet dust removal in the field of production of organic silicon and polycrystalline silicon, and has strong applicability and popularization.

Drawings

FIG. 1 is a schematic flow chart of a wet dedusting method using a cyclone scrubber and using scrubbing liquid as high-boiling substances in a tower kettle.

FIG. 2 is a schematic flow diagram of a wet dedusting method using a cyclone scrubber and the scrubbing liquid is the crude product condensed at the top of the tower.

FIG. 3 is a schematic flow chart of a wet dedusting method using a spray scrubbing deduster and scrubbing liquid as tower kettle high-boiling residue.

Wherein, 1A-cyclone washing dust remover; 1C-spray washing dust remover, 2-washing tower, 3-washing tower top condenser, 4-washing tower reboiler, 5A-tower kettle washing liquid delivery pump, 5B-condensed washing liquid delivery pump, and 6-tower kettle washing liquid recovery tank.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

example 1

As shown in figure 1, an improved wet dust removal method for an organosilicon and polysilicon production system. The device comprises the following equipment: a cyclone washing dust remover 1A, a washing tower 2, a washing tower condenser 3, a washing tower reboiler 4, a tower kettle washing liquid delivery pump 5A and a tower kettle washing liquid recovery tank 6; the gas phase inlet of the cyclone washing dust remover 1A is connected with the gas phase outlet of the dry dust removing device, and the gas phase outlet is connected with the inlet of the washing tower 2; the liquid phase inlet is connected with the tower kettle of the washing tower, and the liquid phase outlet is connected with the inlet of the washing liquid recovery tank 6 of the tower kettle. A plurality of small holes which are uniformly distributed are formed in the upper part of the cyclone washing dust collector 1A, and the crude product washing liquid flows down along the inner wall of the dust collector through the small holes uniformly to form a washing liquid film which flows continuously and uniformly, so that the washing liquid is ensured to be in full contact with the reaction gas.

The method comprises the following specific steps: firstly, introducing reaction gas containing a small amount of silicon powder less than 10 mu m into a cyclone washing dust remover after passing through a dry dust removal device, and then sending the reaction gas subjected to dust removal by the cyclone washing dust remover into a washing tower for washing and primary separation. The method is characterized in that the washing liquid used by the cyclone washing dust remover is high-boiling-point substances in the tower kettle of the washing tower, the washing liquid containing fine silicon powder after washing and dust removal is sent into a washing liquid recovery tank, and liquid-phase products in the washing liquid recovery tank are heated and evaporated again and sent back to a washing system. Controlling the gas phase temperature of the cyclone washing dust remover to be 180-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-65 ℃; the temperature of a reboiler of the tower kettle is controlled to be 120-440 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 440 ℃. The liquid-gas ratio of the cyclone washing dust remover is controlled to be 0.3-2.0.

Compared with the existing industrial process, the process scheme has the dust removal effect of 85-95% on fine silicon powder with the particle size of less than 10 microns. Therefore, the high-boiling residue slurry with low added value is only produced in the washing liquid recovery tank, the tower bottom of the washing tower is a high-boiling residue which hardly contains silicon powder, and the residue slurry yield can be reduced by about 30-50% compared with the existing flow. And the dust accumulation rate of the tower plate of the washing tower is obviously reduced, and the shutdown condition of the production device caused by dust accumulation is obviously improved.

Example 2

As shown in fig. 2, an improved method for wet dust removal of an organosilicon and polysilicon production system. The device comprises the following equipment: the device comprises a cyclone washing dust remover 1A, a washing tower 2, a washing tower top condenser 3, a washing tower reboiler 4, a condensed washing liquid conveying pump 5B and a washing liquid recovery tank 6. Unlike example 1, the liquid phase inlet of the cyclone scrubber 1A is no longer connected to the bottom of the scrubber but is connected to the top condenser 3 of the scrubber via a scrubber liquid feed pump 5B. For the flow, the washing liquid does not use high-boiling liquid, but washes the crude product liquid obtained by condensation. At the moment, the gas phase temperature in the cyclone washing dust remover is controlled to be 150-510 ℃; controlling the temperature of an outlet of a condenser 3 at the top of the washing tower to be-10-95 ℃; controlling the temperature of a reboiler at the tower kettle to be 120-410 ℃; the temperature of the washing liquid recovery tank 6 is controlled between 150 ℃ and 410 ℃. The liquid-gas ratio of the cyclone washing dust remover is controlled to be 0.3-2.0.

Compared with the existing industrial process, the process scheme has 88 to 97 percent of dust removal effect on fine silicon powder with the particle size of less than 10 mu m, and is better than the process scheme in the embodiment 1; compared with the prior process, the yield of the slurry can be reduced by about 35 to 60 percent. Meanwhile, because the washing liquid is crude product liquid obtained by condensation, the process heat load is increased by 5-20% compared with the prior art, and the recovery rate of the process target product is reduced by 0.5-2%.

Example 3

As shown in fig. 3, an improved method for wet dust removal of an organosilicon and polysilicon production system. The device comprises the following equipment: a spray washing dust remover 1C, a washing tower 2, a washing tower condenser 3, a washing tower reboiler 4, a washing liquid delivery pump 5A and a tower kettle washing liquid recovery tank 6. In contrast to example 1, the scrubbing dust collector used was not a cyclone scrubbing dust collector but a spray scrubbing dust collector. At the moment, the gas phase temperature in the cyclone washing dust remover is controlled to be 180-510 ℃; controlling the temperature of the outlet of a condenser at the top of the washing tower to be-10-65 ℃; the temperature of a reboiler of the tower kettle is controlled to be 120-440 ℃; the temperature of the washing liquid recovery tank is controlled between 150 ℃ and 440 ℃. The liquid-gas ratio of the spray washing dust remover is controlled to be 1.5-3.5.

Compared with the existing industrial process, the process scheme has the dust removal effect on fine silicon powder with the particle size of less than 10 mu m of 85-95 percent; compared with the prior process, the yield of the slurry can be reduced by about 25 to 45 percent.