公开(公告)号：US20030108473A1

公开(公告)日：2003-06-12

申请号：US10349065

申请日：2003-01-22

Applicant: Ashland Inc.

Inventor： Daniel J. Dershowitz ,  Ryan L. Mears ,  Jay F. Schnaith ,  Curtis Dove ,  Sadhana Mahapatra ,  Kevin K. Wadsworth

IPC: C01C001/02 ,  F26B007/00

CPC classification number: C01C1/024

Abstract: Commercial grade ammonia is purified for use in production of semiconductors by initially passing the liquid ammonia through a liquid phase oil separation system. This removes the vast majority of the impurities. The filtered liquid ammonia is then passed through a vaporizer which quiescently forms ammonia vapor and prevents entrainment of impurities within the ammonia vapor. The vapor passes through a vapor filtration system and subsequently to a bubble column. The bubble column is designed so that the bubbles are small enough and travel at a rate which ensures that any entrapped particle within the bubble will have time to migrate to the surface of the bubble and thereby pass through the liquid phase. The collected vapor is directed through subsequent vapor filters and is collected. If anhydrous ammonia is desired, the ammonia vapor is collected upstream of the bubble column.