Novel Materials, Processes and Technologies
20.3 DESIGN & DEMONSTRATION OF lpm anhydrous hydrogen chloride with 5 lpm nitrogen (as diluent) TRICHLORO SILANE (TCS) PRODUCTION to produce trichlorosilane at 10 kg/day rate by the following TECHNOLOGY IN BENCH SCALE LEVEL. reactions.
Silicon in various grades is the most popular raw material for semiconductor industry. Large scale production of semiconductor grade silicon requires TriChloroSilane (TCS) as feed Hydrogen chloride and nitrogen gas is mixed in a mixing tank stock for its relative ease of purification to the desired degree. and then heated to the desired temperature before feeding in This is highly inflammable, corrosive and hazardous material. the fluidized bed reactor. Silicon is fed to the reactor from a bin o Present indigenous effort in Heavy Water Division, is to produce intermittently. Reactor is maintained at 240 C and slightly above crude trichlorosilane (main impurity is silicon tetrachloride), from atmospheric pressure to obtain optimum yield. The gaseous metallurgical grade silicon powder and anhydrous hydrogen stream from the reactor passes through a set of cartridge filter o chloride gas as raw material. This will be purified further by and cooled in a condenser to –80 C by dry ice in acetone. Most distillation. of the trichlorosilane produced is condensed in this condenser and non-condensables such as hydrogen and un-reacted
Sufficient quantity of TCS was produced for further processing. hydrogen chloride are scrubbed by sodium hydroxide to neutralise The plant has been operated successfully for sufficient time. hydrogen chloride. The rest is vented to atmosphere. Condensed crude trichlorosilane is stored in an insulated 100 litre storage tank.
The test facility uses 75 mm diameter and 2250 mm tall, fluidized V. K.Tangri
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138 BARC HIGHLIGHTS Chemical Sciences & Engineering