This is the second book in a three-volume series on the various surface unit in production facilities. This book is hoped to serve three needs. First, in the form of typed notes, the current material has been used as a text for a senior-level, petroleum engineering design course on surface production and processing. Second, this book material has been used in short courses for engineers and foremen working in field handling of natural gas. Thirdly, this book should serve as a refresher and handbook for all engineers interested in natural gas processing.