STC-to-TCS Thermal Conversion

PPP Equipment Corporation (PPP-E) and Poly Plant Project (PPP) provide our customers with the latest, proven technology package for high yield STC-to-TCS Thermal Conversion. Our technology has been implemented at multiple plants successfully.

STC-to-TCS Thermal Conversion

One of PPP-E’s solutions for recovering and recycling STC produced in the Polysilicon Deposition Reactors is STC-to-TCS Thermal Conversion. This system converts recovered Silicon Tetrachloride (STC) back into useable TCS and is similar to the process for TCS deposition. Liquid STC and hydrogen gas pass through a separate Fluid Delivery System (FDS) to precisely control the feed mixture of both components into the Reactor. The mixture of liquid STC/hydrogen is passed through a vaporizer, which converts the STC/hydrogen mixture from liquid to superheated gas. The feed stream is piped into the Converter at a pressure.

The gas is injected via a distribution system consisting of a series of nozzles designed to optimally distribute the STC/H2 mixture into the Converter. The gas is heated using specially designed system of graphite elements located within graphite shields. Within this “hot zone” STC is converted to TCS.

The vent gas from the Converter is sent through an off-gas cooling system to be cooled. From the off gas cooler, the effluent gas is sent to a Vent Gas Recovery (VGR) system for separation. The vent gases are recycled and reused.