Carbon dioxide separation and regeneration study from power plant flue gases with reclaimed magnesium hydroxide

A method of inexpensively and reliably separating CO2 from flue gases by means of using magnesium hydroxide (Mg(OH)2) has been studied. Mg(OH)2 may be easily and economically reclaimed from power plants using magnesium enhanced flue gas desulfurization systems (ME-FGD). The CO2 scrubbing system may be operated as either a once-through system which produces magnesium carbonate for sequestration of carbon, or as a regenerable system where a concentrated CO2 gas stream is created for further processing.; The results of experimental investigations and energy considerations are given. The experimental results indicate that CO2 is easily absorbed into solutions containing reclaimed Mg(OH)2.; In addition, a study was undertaken to determine the mass transfer characteristics of the bubble column reactor.{09}A model describing CO2 absorption into clear solutions from a bubble was developed assuming a known bubble size, solution equilibrium chemistry and overall mass transfer coefficients from the gas phase to the liquid. The overall mass transfer coefficients were found to vary from 6.05 x 10-6∼6.63 x 10-7 cm/s for the temperature range of 22°C∼60°C.; Next, this research also include the results of a study using a Turbulent Contact Reactor (TCA) to study the absorption characteristics of CO 2, from a simulated flue gas using sodium hydroxide (NaOH) and magnesium hydroxide (Mg(OH)2) slurries. The results indicated that a lower fluidized velocity, more CO2 absorption using a NaOH solution, but optimum fluidized velocity was required with Mg(OH)2 slurry using this system.; Finally, the energy requirements for CO2 separation were also evaluated for a regenerable system based on equilibrium data in the liquid phase.{09}A liquid solution equilibrium solver, MINEQL+, was used to determine the equilibrium values.{09}The economic evaluation is based on a 500-MW power plant burning a high sulfur coal. These calculations show that approximately 40 to 68 MW of energy are required to separate 7% of the CO2 from the flue gas stream. (Abstract shortened by UMI.)...