Aminosilicone Solvent Technology for CO2 / H2 Separation

We have successfully developed over the last seven years a platform of cost effective CO₂ capture technologies based on a non-aqueous, aminosilicone solvent to reduce CO₂ emissions from PC power plants.⁽¹⁾ These technologies have made great strides toward achieving the DOE goals of 90% CO₂ capture rate, 95% CO₂ purity, and 30% reduction in the cost of electricity relative to monoethanol amine (MEA). The advantages of the aminosilicone technology are its higher CO₂ loading capacity, low volatility, low corrosivity, low heat capacity, and the absence of water as a co-solvent.  

The presentation will focus on the applicability of the aminosilicone technology for separating CO₂ from the H₂ stream of a steam methane reforming H₂ plant. Conditions of the inlet stream in the CO₂ separation/capture plant are drastically different in the H₂ plant (450 Psi; 16 % CO₂, 5 % CH₄, balance H₂) vs. a typical coal fired power plant (14 Psi; 6 % O₂, 12 % CO₂, balance N₂). Therefore, methane and hydrogen solubilities in the aminosilicone working solution have been measured in a pressurized reactor at the absorber outlet conditions. CO₂ capture ASPEN^TM process model, previously developed for a coal fired power plant, has been tuned for the H₂ plant inlet conditions.  The model was further modified to match the experimental for H₂ and CH₄ solubilities. Mass / heat balance sensitivity studies were then performed to evaluate the effect of solvent recirculation rate, absorber and desorber conditions upon hydrogen throughput, CO₂ capture rate and CO₂ purity. Finally, the advantages and challenges of implementing the aminosilicone solvent vs. the baseline aqueous amine ⁽²⁾ will be discussed .

1. NETL awards DE-NT0005310, DE-FE0007502, and DE-FE0013755

2. http://www.energy.alberta.ca/CCS/BDEPAmineUnitAppendix.pdf