The Optimum Number of Trays and Solvent Circulation Rate in Removing Acid Gases in Absorption Unit

Abstract

Removal of acid gases from natural gas is very important as to meet the sale’s specifications and environmental regulations. It is also a measure to minimize the corrosion effects. The most common process to remove the acid gases is amine process. There are some operating parameters which can be considered to optimize amine sweetening plant such as inlet gas temperature, lean amine circulation rate, lean amine temperature, amine concentration, number of trays and others. The objectives of the project are to study the optimum number of trays of absorber and amine circulation rate in removing acid gases in absorption unit using HYSYS simulator which capable in designing the process. By using HYSYS software, a base case of amine sweetening unit was created and di-ethanolamine (DEA) is used as the amine solvent. Four samples at different concentrations of acid gases were tested. The rules evaluated include 20 trays in the absorber and higher circulation rate. Although these rules of thumb are excellent as the starting points, violating these rules could offer considerable advantages to process efficiency. Depending on the concentration of the acid gases at the feed stream, every situation is different and requires a thorough investigation whether some changes are beneficial or not.