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Fluidized bed riser reactor and method for producing high-purity polysilicon particles

A riser and reactor technology, applied in the direction of silicon, etc., can solve the problems of reduced reaction efficiency, low thermal efficiency, uneven heating of silicon powder particles, etc., to achieve the effect of reducing or wall deposition, improving product purity, and eliminating wall deposition

Active Publication Date: 2017-03-08
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This heating method also helps to reduce dust generation, but it does not effectively improve the problem of wall deposition
CN101318654B separates the heating zone and the reaction zone of the fluidized bed reactor from each other structurally, feeds fluidizing gas in the heating zone, and the polysilicon particles are fluidized and heated in the heating zone, and the heated polysilicon particles are transported to the reaction zone. The silicon-containing gas is introduced into the zone and reacts, and the generated elemental silicon is deposited on the surface of the polysilicon particles. Since the polysilicon particles are heated in the heating zone, the fluidization gas will take away a large amount of heat, the thermal efficiency is low, and the generation of dust has not been fundamentally solved. question
CN102502646B uses a cyclone separator to separate tail gas and silicon powder particles, and the separated silicon powder particles are transported to a storage tank to be heated. This heating method is likely to cause uneven heating of the silicon powder particles, thereby reducing the reaction efficiency

Method used

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  • Fluidized bed riser reactor and method for producing high-purity polysilicon particles
  • Fluidized bed riser reactor and method for producing high-purity polysilicon particles
  • Fluidized bed riser reactor and method for producing high-purity polysilicon particles

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Experimental program
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Effect test

Embodiment 1

[0033] Such as figure 1 with figure 2 As shown, a circulating fluidized bed riser reactor for preparing high-purity polysilicon particles includes a riser reactor 1, a cyclone separator 6, a product collector 4 and each connecting pipeline; wherein the riser reactor 1 Including riser 2, gas distributor 3, tail pipe 22, silicon-containing gas inlet 14, fluidization gas inlet 15, gas-solid transportation pipeline 7 inlet and solid phase transportation pipeline 5 outlet; cyclone separator 6 An electric heating wire 17, a silicon seed inlet 19, an exhaust gas outlet 18, an outlet of a gas-solid transportation pipeline 7 and an inlet of a solid phase transportation pipeline 5 are provided; the product collector 4 is arranged at the bottom of the tail pipe 22;

[0034] Wherein, gas distributor 3 is made of cap 13 and conical distribution plate 12, and the space enclosed by the two is a gas buffer zone; cap 13 is provided with silicon-containing gas inlet 14; The gas distribution ...

Embodiment 2

[0043] Such as image 3 As shown, different from Embodiment 1, the product collector 4b is arranged at the bottom of the cyclone separator 6, and the fluidizing gas inlet 15 is arranged on the bottom surface of the tail joint 22; by controlling the inlet velocity of the fluidizing gas inlet 15, the lifting All the silicon powder particles in the tube reactor are pneumatically transported upwards and enter the cyclone separator 6 with the tail gas. Part of the polysilicon particle product 16 with larger particle size is taken out to the product collector 4b by sieving at the lower part of the cyclone separator 6, and part of the particles Silicon powder particles with smaller diameters are recycled back to the riser reactor 1. The advantage of this method of retrieving materials is that the polysilicon particle product undergoes high-temperature heating before being taken out, which can remove the residual hydrogen bonds on the surface of the polysilicon particle and help to im...

Embodiment 3

[0045] Different from Example 1, the silicon-containing gas inlet 14 feeds silicon-containing gas SiHCl 3 and H 2 Mixed gas; due to SiHCl 3 The reaction temperature required for hydrogen reduction is higher than that of SiH 4 The pyrolysis reaction temperature, the silicon powder particles are heated to 1200° C. by the electric heating wire 17 in the cyclone separator 6 .

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Abstract

The invention provides a fluidized bed riser reactor and a method for preparing high-purity polycrystalline silicon particles. The fluidized bed riser reactor comprises a riser reactor, a cyclone separator, a product collector and a connection pipeline. The invention further provides a method for preparing high-purity polycrystalline silicon particles with the circulating fluidized bed riser reactor. Silicon-containing gas is introduced into a fluidized bed layer through a gas distributor, so that silicon particles in the fluidized bed layer are fluidized and have a heterogeneous chemical vapor deposition reaction on surfaces of high-temperature silicon particles, generated monatomic silicon is deposited on the surfaces of the silicon particles, the silicon particles grow constantly and circulate between the riser reactor and the cyclone separator, and the surface deposition and the heating process are alternately performed until the sizes of the particles meet requirements of polycrystalline silicon particle products. The fluidized bed riser reactor and the method have the advantages of small dust amount, little wall surface deposition, high product quality, uniform particle size, simple structure, low energy consumption and the like.

Description

technical field [0001] The invention relates to the fields of chemical equipment and chemical technology, in particular to a circulating fluidized bed riser reactor and a method for preparing high-purity polysilicon particles. Background technique [0002] Polysilicon is widely used in the semiconductor and photovoltaic industries. In recent years, with the rapid development of the photovoltaic industry, the demand for polysilicon in the world has grown rapidly. In 2012, the output of polysilicon reached 170,000 tons, of which the consumption of photovoltaic industry accounted for as high as 85%. Polysilicon production technology is the most important link in the photovoltaic industry chain, while environmental protection and energy consumption issues have always been the bottleneck of the polysilicon industry. [0003] At present, the main process for producing polysilicon in the world is the improved Siemens method, and its production capacity accounts for about 80% of th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/03
Inventor 李学刚肖文德阎建民
Owner SHANGHAI JIAOTONG UNIV