Mass transfer method and apparatus

A method for transferring mass between a flow of a first fluid and a flow of a second fluid, one of the fluids being a gas phase and the other being a liquid phase, the method comprising contacting the first fluid with the outer surface of a plurality of hollow tubular members, at least a part of the walls of the hollow tubular members comprising porous membranes of poly(halogenated olefins) with gas-containing pores that have an average pore size between 0.1 and 1.5 μm, and contacting the second fluid with the inner surface of said hollow tubular members;

• the hollow tubular members being arranged parallel to each other or at angles to each other thereby defining an array of hollow tubular members, the plurality of hollow tubular members further defining interstices therebetween through which interstices the first fluid is moved in a transverse direction relative to the longitudinal direction of the hollow tubular members;
• the mass transfer coefficient of the membrane (Ki,m) with respect to said mass being at least 1 cm/s and further being at least one tenth of the mass transfer coefficient of the gas phase (Ki,g) with respect to said mass;
• the packing fraction of the array of hollow tubular members being in the range of 0.2 to 0.8;
• the pressure drop over the array of hollow tubular members being at the most 4000 Pa;
• and, wherein the membrane area per cubic meter of gas phase handled per second (Am/G) for C1/C2 is equal to or greater than 20 and is defined by
• Am/G=In((C1−C*1)/(C2−C*2))/K0
• wherein K0 is the overall mass transfer coefficient, C1 being the inlet concentration, in the gas, of the component in question, is at most 200 m2/(m3/s) where each of the equilibrium concentrations of the gas component in question over the liquid phase C*1 and C*2 is at most 0.05C, and wherein the thickness of the membrane is in the range of 5-200 μm.