Influencia de las condiciones de  operación en el refino de biogás  para producir biometano mediante  contactores de membrana

Authors

In this paper, the behavior of micro-porous hollow fiber

membrane contactors has been studied for biogas upgrading

under different operational conditions. Physical solvents, as

deionized water and sodium chloride solution, were initially

used. In these cases, carbon dioxide absorption was dependent

upon liquid phase flow. Sodium hydroxide was subsequently

used as a comparative chemical absorption solvent. In this case,

CO2 mass transfer increased by increasing gas velocity which

was attributed to the excess of reactive hydroxide ions present

in the solvent. Under optimum conditions, with two membrane

contactors operating in series, it was possible to obtain a gas

stream with more than 99% of pure methane using deionized

water as solvent. The same yields were obtain with NaOH as

solvent, but in this case working with just one membrane

module, that is, reducing by half the available surface area

for molecules diffusion. At constant liquid to gas flow ratios,

better separation behavior was targeted at pressures higher

than 2.0 barg. When dealing with solvent reuse without

regeneration, NaOH is the only absorbent allowing a high

number of solvent recirculation cycles. This aspect could be

very interesting for the economy of the process.