Karl Anders Hoff

Process modifications for solvent-based post-combustion CO2 capture

Abstract One of the major limitations to the implementation of amine based post-combustion CO 2 capture (PCC) technology is the high efficiency loss induced by the process. Minimizing this loss can be achieved by either formulating new solvents and/or optimizing the process flow-sheet and/or its integration with the power plant. Amine based CO 2 scrubbing processes have been patented since 1930 but very few process improvements have been reported prior to the oil crisis of 1975–1980, which led to the requirement for more energy efficient processes. Nevertheless most of these patents are solvent oriented. With CO 2 capture technology development, a sharp increase of process improvement patents and scientific articles can be witnessed since 2004 in parallel with the development of new solvents. In this work, a thorough review of patent database and open literature has been carried out in order to be as exhaustive as possible. The individual process modifications are analyzed and then generalized into “elementary” modification groups. These 20 elementary modifications are then sorted out in 3 main categories related to their effect on the process: linked to absorption enhancement, heat integration and heat pump. Absorption enhancement includes 6 modifications: intercooled absorber (ICA), rich solvent recycle (RSR), interheated absorber (IHA), split flow arrangement (SFA), double loop absorber (DLA), flue gas compression and expansion (FCE). Heat integration includes 9 modifications: rich solvent splitting (RSP), rich solvent preheating (RSP), rich solvent flashing (RSF), parallel economizer arrangement (PEA), interheated stripper (IHS), heat integrated stripper (HIS), overhead condenser bypass (OCB), vacuum operated stripper (VOC), multi-effect stripper (MES). Heat pump includes 5 modifications: lean vapor compression (LVC), rich vapor compression (RVC), integrated heat pump (IHP), stripper overhead compression (SOC), multi-pressure stripper (MPS).

Pilot Plant Study of 3-(methylamino)Propylamine Sarcosine for Post-combustion CO2 Capture

Publisher Summary To meet the global energy demand and at the same time reduce global warming, scientist are faced with challenges of finding new and more efficient ways of increasing the energy production while reducing the emissions of the major green house gas, CO2 to the atmosphere, the major source for energy being fossil fuel combustion. One method of mitigating CO2 emissions is post combustion CO2 capture from large point sources such as power plants, oil refineries, petrochemical facilities, fertilizer and gas-processing plants, steel works and pulp and paper mills and its further utilization in many technologies such as coal conversion, organic synthesis, destructive oxidation of hazardous wastes, enhanced oil recovery and activated carbon regeneration. One of the most attractive methods of CO2 separation from such point sources is absorption with chemical reaction using amine solutions. Amines such as monoethanolamine (MEA), diethanolamine (DEA), di-isopropanolamine and methyldiethanolamine (MDEA) have been used industrially over many years, however some of these amines have been found to have adverse effects on the environment.

Modeling of Membrane Reactor

A two-dimensional model for a membrane reactor used for the absorption of CO2 into amines was developed and two solution procedures were tested for the combined diffusion-reaction problem. The method of lines/finite difference method is the fastest and most stable, but conservation of mass is not guaranteed. The finite volume method needs very good initial estimates to converge, and is much slower. This shows a potential problem in the use of commercial CFD-codes for coupled fluid dynamic, diffusion, and chemical reaction problems. The model has been validated with respect to effects of steep wall diffusivity profiles, membrane pore penetration, and available gas/liquid contact area. The agreement between simulated and experimental absorption fluxes is very good, and the experimental unit is found to have good sensitivity for obtaining kinetic and diffusion parameters.