초록

Purified SiHCl3 and/or SiCl4 are used as a sweep gas across a permeate side of a gas separation membrane receiving effluent gas from a polysilicon reactor. The combined sweep gas and permeate is recycled to the reactor.

대표청구항 ▼

1. A method for recycling an effluent gas generated during polysilicon or silane production, comprising the steps of: directing the effluent gas comprising at least SiHCl3, SiCl4, HCl, and H2 from a purification unit, a STC converter, and/or a polysilicon deposition reactor to a condenser to produce

1. A method for recycling an effluent gas generated during polysilicon or silane production, comprising the steps of: directing the effluent gas comprising at least SiHCl3, SiCl4, HCl, and H2 from a purification unit, a STC converter, and/or a polysilicon deposition reactor to a condenser to produce a condensate and a non-condensate, the condensate comprising predominantly SiHCl3 and SiCl4, the non-condensate comprising a major amount of H2, a minor amount of chlorosilanes comprising SiHCl3, SiCl4, and a minor amount of HCl;directing the non-condensate to a compressor and then to a gas separation unit comprising at least one gas separation membrane;directing a sweep gas comprising SiHCl3 or SiCl4 to a permeate side of the membrane;recovering a recycle gas from the permeate side, the recycle gas comprising H2 permeated through the membrane from the non-condensate and SiHCl3 or SiCl4 from the sweep gas; anddirecting the recycle gas to a hydrochlorination reactor, the STC converter, and/or the deposition reactor. 2. The method of claim 1, further comprising the steps of: recovering a H2 lean stream from the gas separation unit, the H2 lean stream comprising SiHCl3, SiCl4, HCl, and H2;directing the H2 lean stream to a SiHCl3 production process; andobtaining purified SiHCl3 or SiCl4 from the SiHCl3 production process, wherein the sweep gas comprises at least a portion of the obtained purified SiHCl3 or SiCl4. 3. The method of claim 1, wherein the recycle gas is not compressed before being directed to the STC converter and/or the deposition reactor. 4. The method of claim 1, wherein at least 50% of H2 in the effluent gas permeates to the permeate side. 5. The method of claim 1, wherein at least 90% of H2 in the effluent gas permeates to the permeate side. 6. The method of claim 2, wherein said SiHCl3 production process comprises the steps of: separating the H2 lean stream into light gases and heavier components, the heavier components comprising predominantly SiHCl3 and SiCl4, the light gases comprising a major amount of H2, a minor amount of chlorosilanes comprising SiHCl3, SiCl4, and a minor amount of HCl;directing the light gases to an adsorption unit wherein the major amount of H2 is stripped and the minor amount of HCl is separated from the minor amount of chlorosilanes;directing the heavier components and the chlorosilanes to a distillation unit comprising at least one distillation column; andproducing the purified SiHCl3 at the distillation unit. 7. The method of claim 6, wherein said SiHCl3 production process further comprises the steps of: feeding Si and the HCl separated from the chlorosilanes to a chlorination reactor thereby producing impure SiHCl3;purifying the impure SiHCl3 at a purification unit to produce a chlorosilane mixture feed;directing the chlorosilane mixture feed to the distillation unit. 8. A system for recycling effluent gas generated during polysilicon or silane production, comprising: a condensation unit having an inlet, a condensate outlet, and a vapor outlet, the inlet being in communication with an effluent gas outlet of a purification unit, a STC converter, and/or a polysilicon deposition reactor;a compressor having an inlet and an outlet, the inlet being adapted and configured to fluidly communicate with the vapor outlet of the condensation unit;a gas separation unit comprising at least one gas separation membrane, an inlet, a permeate outlet, and a retentate outlet, the inlet being adapted and configured to fluidly communicate with the outlet of the compressor, the permeate outlet being adapted and configured to fluidly communicate with a feed inlet of a hydrochlorination reactor, the STC converter, and/or the deposition reactor;a reflux absorber having an inlet, a condensate outlet, and a vapor outlet, the inlet being in communication with the retentate outlet; anda SiHCl3 production unit adapted and configured to produce purified SiHCl3 comprising an inlet in fluid communication with the condensate outlet of the reflux absorber and an outlet in fluid communication with a permeate side of the membrane. 9. The system of claim 8, wherein the membrane has a higher permeability to H2 than SiHCl3, HCl, and SiCl4. 10. The system of claim 8, wherein there is no compressor in between the permeate outlet and the feed inlet. 11. The system of claim 8, further comprising: an adsorption unit adapted and configured to strip H2 from a SiCl4, SiHCl3, HCl, and H2 containing vapor from the vapor outlet of the reflux absorber and separate the remaining SiCl4, SiHCl3, and HCl into HCl and chlorosilanes comprising the remaining SiCl4 and SiHCl3; anda distillation unit having inlets in fluid communication with the reflux absorber outlet and the adsorption unit and having a purified SiHCl3 or SiCl4 outlet in fluid communication with the inlet of the membrane. 12. The system of claim 11, further comprising: a first SiHCl3 reactor having reactant inlets in fluid communication with a source of Si and the adsorption unit; anda purification unit having an inlet and outlet, the purification unit inlet being in fluid communication with an outlet of the first SiHCl3 reactor, the purification unit inlet being adapted and configured to receive impure SiHCl3 from the first SiHCl3 reactor, the purification unit outlet being in fluid communication with an inlet of the distillation unit.