In manufacturing sites such as chemical plants, electronic component factories, and metal processing plants, as well as in civilian applications such as gas stations, dry cleaning plants, and printing plants, the amount of volatile organic compounds (VOCs) and solvent vapors released into the atmosphere is immense. In the case of Freons, which have been conveniently used in electronic component factories, they have become a problem due to their association with global environmental issues and the destruction of the ozone layer. As a result, efforts have been made to replace Freons with other solvents to prevent their release into the atmosphere. However, efforts to minimize the emission of various other organic solvent vapors continue to be necessary from an environmental and resource-saving perspective.
Currently, the separation process that is practically applied for the recovery of organic solvents from exhaust gases mainly involves adsorption processes using activated carbon or zeolites. Many technological developments have been made in the solvent recovery process through adsorption, which is already an established method. However, the adsorption process requires a regeneration step. As a simpler and more energy-efficient method of organic vapor recovery and recycling, the membrane separation process has gained attention.
Membrane separation utilizes the specific selective permeability of the membrane material to the components to be separated. Generally, membrane separation is suitable for local exhaust treatment with low to medium concentration VOCs.
NAGASEP is a separation membrane module made of solely silicone rubber, possessing excellent characteristics for the separation and concentration of organic vapors. The device is of a simple structure, consisting only of a membrane module, a vacuum pump, and a vapor recovery container. The supply side of the membrane is at atmospheric pressure while the permeation side is under reduced pressure, enabling continuous concentration and recovery of VOCs from the atmosphere. For example, it is used for the concentration and recovery of hexane from factory exhaust gases or the recovery of gasoline VOCs emitted from the refueling ports at gas stations.
