The Problem
A major manufacturer of pharmaceuticals in the northeast was having difficulties with its methanol/water distillation column. The feed rate to the column had increased dramatically, causing a capacity problem. The tower was filled with 2″ Pall Rings, which were not performing to the desired efficiency, as the column had reached a flooding condition. With the excess flow diverted straight to the plant’s wastewater treatment plant, bypassing the column, two serious problems were created:1. The methanol was lost from the process, requiring the plant to purchase additional MeOH as a replacement.
2.. The diverted flow was sent directly into the plant’s wastewater treatment facility which raised the Biological Oxygen Demand (BOD) of the wastewater stream. The plant did not have the ability to properly handle the increased BOD levels, and was forced to release an unpermitted effluent stream into the sewer.
Meeting the Requirements
The plant’s process engineering group, while searching for a cost-effective solution, called upon Lantec. Process parameters were reviewed, including the expected top and bottom concentrations in the column. Subsequently, a design recommendation to employ LANPAC 3.5″ media was presented and accepted.
2.3″ Lanpac and 3.5″ Lanpac
The results proved better than expected. To date, the feed rate has been doubled, pressure drop through the tower decreased, and mass transfer efficiency has increased. More methanol is being recovered and returned to the process stream. Since there is no longer any need to bypass the distillation column, the BOD effluent has returned to below permitted discharge limits. Production costs have been reduced, and a major environmental problem was avoided.
