ABSTRACT
Gas treating involves removal of the “acid gases,” carbon dioxide (CO2), and hydrogen sulfide (H2S), along with other sulfur species, to sufficiently low levels to meet contractual specifications, to minimize pipeline corrosion, or to permit additional processing in the plant without corrosion or plugging problems. This chapter focuses on acid gases because they are the most prevalent; when applicable, other sulfur compounds are discussed. It begins with an overview of the need for treating, commonly used treating processes and when they are applicable. The chapter then discusses the widely used chemical absorption processes involving amines as the solvent. A discussion of amine acid gas chemistry is provided to explain CO2 slippage. Operating parameters for the commonly used amines are given and typical operating conditions of amine treating are discussed with emphasis on best practices. The chapter provides an overview of common operating problems and how they can be mitigated. Physical absorption is discussed, and one common process is reviewed. The chapter provides an overview of acid gas removal using adsorption and cryogenic fractionation. Membrane processes are discussed with an example process along with pros and cons of membranes. Nonregenerable scavengers are discussed. The chapter concludes with emphasis on safety aspects.
