Method of Vaporizing Liquids by Microwave Heating

Abstract

A process and apparatus for the purification and vaporization of liquefied gases, such as ammonia, and their decontamination are described. This technique can yield very high flow rates [>1000 l/m] and high purity [< 50 ppb of contaminants such as water vapor, non-volatile residues, and trace metals.].The process uses microwaves to quiescently evaporate the liquid enabling dramatic improvement in product purity. The application of an effective amount of microwave energy maintains the steady evaporation of the liquid to produce a purified vapor atflow rate equal to or greater than 1000 liters/minute without any substantial entrainment of liquid droplets. Contaminants such as moisture, organic compounds, non-volatile residue [NVR], and trace metals are concentrated in the liquid residue (commonly referred to as the heel). Removal of contaminants as oxygen, carbon dioxide, and carbon monoxide can be achieved from the gas stream by the use of an additional adsorption based purification.This microwave evaporation process can be used as a stand alone purification system and/or as supply system connected directly to a tool intended for the manufacture of ultra high purity gallium nitride used in the production of LED’s and lasers.