Separation process of cold hydrogenation synthesis gas

Abstract

This invention discloses a separation process for cold hydrogenation synthesis gas. The synthesis gas exiting the cold hydrogenation reactor undergoes heat recovery and rapid cooling for dust removal. A portion of the condensed chlorosilanes is further cooled by a chlorosilane water cooler and used as the absorbent in the middle of the absorption tower. The circulating mixed gas is cooled by a circulating mixed gas water cooler and then enters the lower part of the absorption tower. Silicon tetrachloride feedstock is then used as the absorbent in the upper part of the absorption tower, while the middle absorbent is cooled chlorosilane. The circulating mixed gas entering from the lower part of the absorption tower achieves separation of the cold hydrogenation product chlorosilane through the middle absorbent chlorosilane and the upper absorbent silicon tetrachloride feedstock. Only circulating water coolant is needed; low-temperature coolants (7°C coolant, -40°C coolant, etc.) are not required for multi-stage condensation of the circulating mixed gas to achieve the separation of the cold hydrogenation product chlorosilane, thus eliminating the need for a dedicated low-temperature coolant system for the cold hydrogenation unit.

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