Abstract: A method of operating a fluidized bed deposition reactor to provide top removal of granular material, including production product is set forth. The vertical generally cylindrical reactor has at least one gas inlet at the lower end, at least one gas and solids outlet at the upper end and a gas/granular product separator connected to the gas and solids outlet. A heated reaction zone located in the lower portion of the reactor includes a fluidized bed; the bed being fluidized to establish a bubbling fluidized bed with a defined stable height. A disengaging space is provided above the stable bed height. A reaction gas is added to the bottom of the reactor, the reaction gas depositing a reaction product coating on the granular particles, the coating being abraded off the granules. The combined flow rate of the fluidizing gas and the reaction gas is adjusted so that a majority of the granular particles are retained in the reactor while maintaining bubbling.

Abstract: A gas-solids contactor modification is described which provides for starting or restarting the gas flow to the gas-solids contactor when it is filled with solid particles while preventing the solids from entering and blocking one or more gas inlets which have diameters greater than the solid particle diameters. The apparatus modification comprises a gas plenum and one or more chambers within the gas plenum located between the contactor inlet and the gas inlet. The wall of the chamber has multiple passageways therethrough that are smaller in diameter than the majority of the bed particles. Gas feed to the plenum must pass through the passageways in the chamber walls before entering the contactor. In one embodiment the total open area of the passageways is at least as large as the cross-sectional area of the gas inlet and the inlet to the contactor.

Abstract: A dual wall axial flow electric heater for leak sensitive applications provides an improved corrosion and leak resistant assembly and includes protective tubes over electrical heater rods, double tubesheets spaced apart by a plenum and leak detectors positioned to sensor leaks through the walls of the protective tubes. The design includes the option of two or more tube bundles with each inserted into opposite ends of a shell surrounding the tube sheets and heaters. The design provides ease of maintenance since each heater rod can be replaced independently while the unit is in service. Variable heat flux is provided from standard single flux heater rods by providing protective tubes of varying diameters. A built-in thermowell is provided to allow the rod temperatures to be monitored directly. Hot spots are avoided by the use of turning baffles and vibration is avoided by use of spider baffles to support the tubes.

Abstract: Two low cost processes for removing boron, phosphorus, carbon and titanium during the process of converting metallurgical grade silicon to electronic grade silicon are described. A first process removes boron and titanium by using one or more high temperature solids removal devices for the removal of solid titanium diboride from a halosilane reactor effluent stream where the high temperature is greater than about 200° C. A second process removes carbon as methane and phosphorus as phosphine by means of a membrane separator which processes all or part of a hydrogen recycle stream to recover hydrogen while rejecting methane and phosphine.

Abstract: A process for removing aluminum and other metal chlorides from liquid chlorosilanes with the steps of: introducing a source of seed into a source of impure liquid chlorosilanes, initiating the crystallization of aluminum and other metal chlorides on the seed from the liquid chlorosilanes in a first agitated vessel, passing the resulting mixture of liquid and solids through a cooler into a second agitated vessel for additional crystallization, transferring the resulting mixture of liquid and solids into a solids removal device, transferring the liquid with reduced solids content to a further process or vessel and transferring the liquid with high solids content into a waste concentration device, passing the resulting liquid with reduced solids content to a further process or vessel and passing the resultant liquid with very high solids content to a waste storage vessel with agitation.