A Comparative Economical Analysis of Technologies for CO2 Removal from Offshore Natural Gas

摘要

In the scenario of the Brazilian Pre-Salt fields, where associated Natural Gas (NG) shows high concentration of CO2, gas conditioning comes out as one of the main challenges. Among the possible capture technologies available, three altenatives stand out for CO2 sequestration: (A) gas permeation through membranes, (B) absorption columns using aqueous blends of ethanolamines and (C) application of hybrid -membrane modules in series with amine absorption and regeneration columns. The main objective of this work is to investigate the technical and economical feasibility of applying these three separation processes on offshore platforms, given the stringent constraints on footprint and equipment weight, and for minimizing NG production and transportation costs. The methodology involves: (i) development of cases based on the Brazilian Pre-Salt gas composition. NG streams with CO2 molar concentrations ranging from 8 to 18% are applied; (ii) Simulations of three process flowsheets, corresponding to each one of chosen technologies - A, B and C; (iii) Equipment sizing; and (iv) Analysis of economic performance through calculation of capital (CAPEX) and operational (OPEX) costs.