Method and system for treatment of a gas stream that contains carbon dioxide

A method for separating carbon dioxide (CO2) from a gas stream, comprising the following steps:

• a) feeding the gas stream to an absorber through which a lean aminosilicone solvent circulates;
• b) reacting the gas stream with the lean aminosilicone solvent within the absorber at a first temperature range, so as to generate a rich aminosilicone solvent stream and a clean gas stream with reduced CO2 in comparison with the initial gas stream;
• c) directing the rich aminosilicone solvent stream to a desorber (solvent regenerator) that heat-treats the rich solvent in an endothermic desorption/regeneration reaction that is carried out at a second temperature range higher than the first temperature range;
• to regenerate lean aminosilicone solvent and to produce carbon dioxide gas;
• d) directing the regenerated, lean aminosilicone solvent through a steam-producing, indirect heat exchanger configured to supply steam to the desorber apparatus at a temperature high enough to augment the desorption reaction, while also providing a heat of reaction sufficient to sustain the endothermic desorption reaction and to lower the partial pressure of CO2 in the vapor phase in the lower region of the desorber;
• e) boiling an amount of steam in the indirect heat exchanger in excess of an amount that is required to provide the heat of reaction for aminosilicone desorption, so as to maintain steam in the vapor phase in the upper region of the desorber;
• and
• f) adding selected amounts of make-up water to the rich aminosilicone solvent stream, at one or more process locations between an exit site for the absorber and an inlet site for the desorber, to lower the viscosity of the rich aminosilicone solvent and to lower the temperature required for the desorption reaction.