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.