Main Sector of relevance\IRC classification 6. Energy

6.4 Automated semicommercial plant for obtaining grained silicon with the use of silicomethane-hydrogen mixture thermal decomposition in boiling bed reactor

Developers’ contact information

1) State Scientific Institution “The A.V.Lykov Institute of Heat and Mass Transfer of National Academy of Sciences of Belarus”
15 P.Brovka Street, Minsk BY-220072
Tel.: +375 (17) 284-10-57, fax: +375 (17) 292-25-13; e-mail: dsl@hmti.ac.by

Summary

The plant is designed for continuous-mode production of grained solar-grade polycrystalline silicon (up to 1mm grain size) from silicomethane.

Description

Plant operation is based on making a boiling (fluidised) bed of fine silicon inoculation particles followed by silicon deposition on their surface.
To achieve this, a quartz reactor is loaded with an original amount of fine silicon inoculation particles with specified size-proportional particle distribution. Then degassing and nitrogen blowdown procedures are carried out for the reactor and gas mains in order to remove moisture and air traces from process fluid. To make a boiling inoculation particle bed, fluidizing nitrogen gas is fed via a gas distributing grating to the reactor bottom during the warm-up procedure. As the boiling bed temperature rises nitrogen is gradually replaced by hydrogen.
When the boiling bed reaches its working temperature the reactor is loaded with silicomethane-hydrogen mixture. The following silicomethane thermal decomposition results in silicon depositing on the surface of silicon inoculation particles. As this takes place the particles grow bigger and form polycrystalline silicon grains. On reaching some particular size they are moved down into the reactor bottom and output. To ensure continuous operation the reactor is then fed with a specified amount of silicon inoculation particles anew.

Technology type

• Process
• Design

Technical advantages and economic benefits

• high efficiency;
• relatively easy to operate and a possibility to arrange continuous automated process;
• low specific energy consumption as compared to core-type reactors available;
• low output self-cost as compared to the conventional Siemens technology.

Technology differentiation and uniqueness

This is the first process technology and process equipment on the territory of Belarus and CIS countries intended for the dynamically developing solar energy industry which is of significant importance at the moment.

Context in which technology was identified

XIIIth Belarusian Energy and Ecology Forum. EXHIBITION.

Technological keywords

Polycrystalline silicon, boiling bed, silicomethane.

Development Stage

• Basic research
• Applied research
• Prototype
• Experimental development stage
• Results of demonstration test available

Intellectual property rights

• Secret know-how

Range of applications

Semiconductor materials production.

Classifier Used at the EU Innovation Relay Centres

• Electronics, IT and Telecommunication
• Energy
• Industrial Manufacturing, Material and Transport Technologies

Preferable Regions

• North America
• South America
• Europe
• Asia
• Africa
• Australia

Practical experience

Plant breadboard model equipped with boiling bed reactor, mathematical models ensuring boiling reactor process and scale-up optimization, basic calculation data on semicommercial plants for obtaining grained silicon with the use of silicomethane-hydrogen mixture thermal decomposition in boiling bed reactor.

Environmental impact

None

Type of collaboration sought

• R&D contract

Terms and restrictions

Joint patenting.

Available technical assistance

• Documentation
• Other:
  Personnel training, installation supersvision.