Reverse Osmosis To Concentrate Lisinopril Purified by Means of Liquid Chromatography:  From Pilot-Plant to Industrial-Scale Unit

Abstract

Reverse osmosis to concentrate the lisinopril after a low-pressure liquid chromatography was tested under various process conditions on a pilot-scale unit. It was found that the permeate flux 20−30 L/hm2 can be kept over the whole concentration range with a feed pressure up to 35 bar and that fouling is negligible. The rejection of lisinopril is almost complete. These data were used for a conceptual design and installation of an industrial scale reverse osmosis unit with the membrane surface area 60 m2 and capacity of 1.5 m3/h permeate. The capital cost estimate is significantly lower compared to a single-stage vacuum evaporator. The operating cost estimate for evaporation is roughly $6.8/kg lisinopril, while the estimated cost for concentration of lisinopril solution with reverse osmosis taking into account the theoretical energy consumption by pumps is $0.23−0.33/kg lisinopril. Cost calculated from actual plant data is even lower, $0.16/kg lisinopril. The validation results of the full-scale unit and its trouble-free operation prove that the decision for reverse osmosis is economically justified and that the scale-up was technically successful.

Separation of Ammonia/Water/Sodium Hydroxide Mixtures Using Reverse Osmosis Membranes for Low Temperature Driven Absorption Chillers

“…In this case, two streams are generated, one with the solvent that crosses the membrane (called permeate) and another one (rejection) more concentrated in solute than the feeding solution. 11,12 Figure 1 shows a block diagram of the proposed absorption refrigeration cycle using a reverse osmosis unit to separate the ammonia/water/NaOH mixture. The poor solution coming from the generator with large sodium hydroxide content enters the reverse osmosis unit that may consist of several membrane modules.…”

“…An external pressure higher than the osmotic pressure is applied to a concentrated solution in contact with a semipermeable membrane, and the solvent permeates across the membrane. In this case, two streams are generated, one with the solvent that crosses the membrane (called permeate) and another one (rejection) more concentrated in solute than the feeding solution. , …”