Carbon Capture Overview
Government research funding initially emphasizing pre-combustion (CO2 capture from syngas) has led to the realization that less-glamorous post-combustion (flue gas scrubbing) most likely represents the best option for timely, cost-effective Carbon Capture and Storage (CCS) in the immediate future. A better understanding of capture costs resulting from the renewed interest in post-combustion has prompted the U.S. Government to increase the acceptable target for increased cost of energy required for flue gas scrubbing from 20% in 2006 to 35% today, highlighting the importance of advancing the current technology. While acid gas removal from process streams using alkanolamines is a mature technology, flue gas scrubbing presents many new challenges still not adequately met on the scale necessary for GHG abatement. In addition to discussing those challenges, this paper reviews (1) flue-gas scrubbing facilities installed over the past 30+ years for commercial purposes such as EOR, urea manufacture, soda ash manufacture and food processing, and (2) current status of innovative technologies employing, for example, sterically hindered amines and aqueous ammonia. While the GHG contribution of sulphur recovery activities is arguably insignificant, potential monetary CO2 reduction incentives will likely improve the economics of reducing incineration fuel by simple, established means as discussed.
Research Results for CO2 Capture from Flue Gas by Aqueous Absorption/Stripping
Alkanolamine absorption/stripping is an important technological option for CO2 sequestration to address global climate change. It has long been a commercial technology for CO2 removal from natural gas and hydrogen. Along with other technical challenges, application of this technology to coal combustion gases must address lower CO2 partial pressures, large gas flow rates, and solvent oxidation. Commercial systems using monoethanolamine (MEA) require potentially prohibitive quantities of steam for stripping. Solvents with a reduced heat of desorption have mixed benefits because they may also increase the stripping steam required, depending on the process configuration. An optimum design will probably have pinches at the lean and rich ends of the absorber and stripper. Piperazine is an effective rate promoter of CO2 absorption in potassium carbonate solvents. These solvents can have rates and capacities comparable to MEA, but with heats of desorption of 50 to 75% of that in MEA. Oxidative degradation of MEA is catalyzed by dissolved iron and dissolved copper with maximum rates in air at 60 o C of about 2 mM ammonia/hr. The catalysis by copper is inhibited by EDTA.
Volatile hydrocarbons in the atmosphere of the Kiel Bight (Western Baltic)
Abstract Volatile hydrocarbons (VHCs) in the Kiel Bight atmosphere were collected by adsorption on silanized porous glass (PG). This material proved to have a good capacity to concentrate VHCs, and it is easy to clean and to maintain free of contaminants. VHC concentrations in the atmosphere of the Bight vary strongly, depending on the wind direction and the amount of precipitation. Southerly, southwesterly and westerly winds are responsible for the transportation of VHCs from the land to the Kiel Bight.