| 摘要 |
<p>A process for continuously regenerating absorbent recovering solvent from an effluent air stream, in which the solvent-containing absorbent is supplied to a desorber, and contacted by stripping gas to remove the solvent. The solvent-saturated stripping gas is fed to a vapour permeation module forming solvent-enriched permeate and a retentate stream with solvent-depleted stripping gas, the latter being re-supplied to the desorption unit via a closed circuit. In the permeate stream from the permeation module, a reduced pressure source follows and is transferred, via the vapour permeation module, into the feed stream. A condensation stage occurs in the permeate stream followed by a portion of solvent-depleted stripping gas being locked-out. The remaining solvent-depleted stripping gas is introduced into the retentate stream. Preferably the locked out fraction of solvent-depleted stripping gas from the condensation stage is supplied to the solvent-saturated effluent air stream, or is disposed of via an adsorption unit. A separator, partly in fluid form, follows the source of low pressure leading back to an intermediate condensate vessel. The gas stream leaving this stage is sent to the stripping gas-stream and saturated with solvent before entering the vapour permeation module. The gas stream leaving the condensate stage is at least partially sent to the retentate stream after the vapour permeation module. The vapour permeation module has a membrane exhibiting a selectivity between solvent and stripping gas /} 10; preferably exceeding 30. Stripping gas is heated before or in the desorption unit and before arriving at the vapour permeation module, is cooled. The stripping gas being steam, air or inert gas.</p> |
