Dittler, R., Shadman, F., Guzman, R. and Muscat, A. (2014) Reducing Ultra-High-Purity (UHP) Gas Consumption by Characterization of Trace Contaminant Kinetic and Transport Behavior in UHP Fabrication Environments, ProQuest Dissertations and Theses.

has been cited by the following article:

• TITLE: A Controlled Mixing Method for Stabilizing the Purity and Reducing the Waste in Gas Delivery Systems

  AUTHORS: Junsheng Wu, Farhang Shadman

  KEYWORDS: High-Purity Gases, Cryogenic, Impurity Drift, Moisture

  JOURNAL NAME: Advances in Chemical Engineering and Science, Vol.9 No.1, December 26, 2018

  ABSTRACT: The variation of impurity concertation in the ultra-high purity (UHP) gases, delivered from cryogenic storage tanks and transported through long pipes, is a major problem in systems like those used in semiconductor manufacturing facilities. A method is developed for stabilizing the purity and reducing the gas consumption in these systems. This technique uses a dynamically controlled mixing of gases supplied by multiple cryogenic tanks. The control scheme uses software modules that simulate the processes that cause purity variation in both the cryogenic tanks and the transport lines. These processes include vaporization and supply in tanks, various modes of transport in delivery pipes, and the adsorption and desorption on surfaces. The method also includes and corrects for variations caused by transience in gas usage rate as well as ambient conditions.