Processes for recovering silane from heavy-ends separation operations
AssigneeMEMC Electronic Materials, Inc.
InventorsZhihui Gu, Timothy D. Truong, Puneet Gupta
Life of this patent
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Abstract
Processes and systems for purifying silane-containing streams are disclosed with relatively less silane being lost in impurity streams by use of distillation and/or condensation operations.
Claims16
A process for purifying a silane-containing stream, the stream comprising silane and one or more compounds having a boiling point greater than silane and being substantially free of trichlorosilane, tetrachlorosilane and tetraflourosilane, the process comprising:
- introducing the silane-containing stream to a heavy-ends distillation column to produce a silane-enriched overhead fraction and a silane-depleted bottoms fraction relative to the silane-containing stream, the silane-depleted bottoms fraction comprising silane and being enriched in one or more compounds having a boiling point greater than silane relative to the silane-containing stream;
- and
- introducing the silane-depleted bottoms fraction to a silane-recovery separation unit to produce a silane-enriched fraction and a silane-depleted fraction relative to the silane-depleted bottoms fraction produced from the heavy-ends distillation column.
A process for purifying a silane-containing stream, the stream comprising silane and one or more compounds having a boiling point greater than silane, the process comprising:
- introducing the silane-containing stream to a heavy-ends distillation column to produce a silane-enriched overhead fraction and a silane-depleted bottoms fraction relative to the silane-containing stream, the silane-depleted bottoms fraction comprising silane and being enriched in one or more compounds having a boiling point greater than silane relative to the silane-containing stream;
- and
- introducing the silane-depleted bottoms fraction to a silane-recovery separation unit to produce a silane-enriched fraction and a silane-depleted fraction relative to the silane-depleted bottoms fraction produced from the heavy-ends distillation column;
- wherein the one or more compounds having a boiling point greater than silane are selected from the group consisting of ethane, ethylene, ethyl-silane, diethyl silane, toluene, dimethoxyethane and mixtures thereof.
A process for purifying a silane-containing stream, the stream comprising silane and one or more compounds having a boiling point greater than silane, the process comprising:
- introducing a feed stream to a light-ends distillation column to produce an overhead fraction and a bottoms fraction, the feed stream comprising silane, one or more compounds having a boiling point greater than silane and one or compounds having a boiling point less than silane, the overhead fraction being depleted in silane and enriched in compounds having a boiling point less than silane, the bottoms fraction being enriched in silane and depleted in compounds having a boiling point less than silane, wherein a portion of the bottoms fraction forms the silane-containing stream that is fed to the heavy-ends distillation column;
- introducing the silane-containing stream to a heavy-ends distillation column to produce a silane-enriched overhead fraction and a silane-depleted bottoms fraction relative to the silane-containing stream, the silane-depleted bottoms fraction comprising silane and being enriched in one or more compounds having a boiling point greater than silane relative to the silane-containing stream;
- and
- introducing the silane-depleted bottoms fraction to a silane-recovery separation unit to produce a silane-enriched fraction and a silane-depleted fraction relative to the silane-depleted bottoms fraction produced from the heavy-ends distillation column;
- wherein the one or more compounds having a boiling point less than silane are selected from the group consisting of hydrogen, nitrogen and methane.
Dependencies are inferred from the claim text.