Patent ID: 8178051
Filing Date: 2012-05-15
Classification: B01J,C01B

Abstract:
1. An improved system for the hydrogenation of a silicon tetrahalide and silicon to trihalosilane including a pressure vessel having no internal flow distributors, one or more gas entry ports, one or more solids entry ports, one or more solids drains, and one or more exits for gas/solids mixtures, a plurality of metallurgical grade silicon particles enclosed within said pressure vessel, the improvement comprising: a first heat exchanger for heating a liquid silicon tetrahalide feed stream, said heated liquid silicon tetrahalide being mixed with hydrogen to reduce the evaporation temperature of the silicon tetrahalide; a second heat exchanger for vaporizing the mixture of silicon tetrahalide and hydrogen, the heat source being hot gases exiting from other components of the system; and a third heat exchanger for increasing the temperature of the vaporized mixture to between about 500-700° C., the heat being provided by an effluent steam from the pressure vessel, said effluent stream exiting the third heat exchanger providing the heat source for the silicon tetrahalide feed stream entering the first heat exchanger.