Abstract: This invention is a heater used to heat the feed process gas from 450° C. to greater than about 600° C. for the fluidized bed reactor (FBR) used for conversion of silicon tetrachloride (STC) to trichlorosilane (TCS). The invention involves stacked heater element carbon plates. The design of the plates allow the plates to act as baffles which improve heat transfer to the feed gas. Also, the heat gradients across each plate is calculated to be approximately 100° C. which is much lower than the gradient seen by conventional vertical heater elements. The design of the present invention prevents electrical grounding. In the design, the elements are surrounded by graphite wrapped in carbon felt to prevent heat loss by radiation and conduction.

Abstract: The present invention relates to a method for producing trichlorosilane having a reduced amount of boron compounds. The method including: (A) reacting metallurgical grade silicon with hydrogen chloride in a fluidized-bed reactor to produce a reaction gas including trichlorosilane; (B) first distilling the reaction gas, for separating first vapor fractions and first residue fractions, by setting a distillation temperature at a top of a distillation column between about a boiling point of trichlorosilane and about a boiling point of tetrachlorosilane and feeding the first vapor fractions to a second distillation column; (C) second distilling, for separating the trichlorosilane and second vapor fractions including boron compounds, by setting a distillation temperature at a top of the distillation column between about a boiling point of dichlorosilane and about a boiling point of trichlorosilane; and (D) feeding back the second vapor fractions to the fluidized-bed reactor.