Process to recover solvents from waste gases
AssigneeMesser Griesheim GmbH
InventorsFriedhelm Herzog, Thomas Kutz, Franz R. Schlomer, Heinz J. Schmidt, Martin Schulte-Rewinkel
Life of this patent
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Abstract
The recovery of solvents from waste gases takes place according to the state of the art by condensation, freezing out or desublimation of the solvent in recuperative cold reservoirs which can be switched over. In order to reduce the amount of equipment and the cold losses, the condensation and freezing-out operations are run continuously in a shaped-object reservoir through which cooled shaped objects move in a countercurrent to the waste gas.
Claims17
A device for recovering solvents from waste gas comprising a reservoir having an upper end and a lower end, a tube system external of said reservoir communicating with said upper end and said lower end of said reservoir to form a closed circuit path of flow, shaped objects consisting of spheres being conveyed in said reservoir in a direction from said upper end to said lower end of said reservoir, a perforated plate in said reservoir collecting said spheres at a location between said upper end and said lower end to form a packing, a transfer lock mounted to said perforated plate for controllably discharging and controlling movement of said spheres from said plate and into said tube system whereby said spheres are continuously conveyed through said closed circuit path, including a heat exchanger in said tube system externally of said reservoir, said spheres passing through said heat exchanger for cooling said spheres externally of said reservoir, a waste gas inlet communicating with said reservoir at said lower end of said reservoir below said plate for feeding the waste gas through said reservoir in a direction countercurrent to said path of flow of said spheres and through said plate whereby said spheres cool the waste gas to freeze out solvents contained in the waste gas so that the solvents solidify and fall downwardly into the lower end of said reservoir where frozen solvent is contacted by warmer waste gas to melt the solvent and with the waste gas continuing to flow upwardly in said reservoir, said lower end of said reservoir having a drain below said waste gas inlet for removing the melted solvents from said lower end of said reservoir, and a waste gas outlet at said upper end of said reservoir for removing cold purified waste gas from said reservoir.
In a process to recover solvents from waste gases including providing a closed circuit path of flow from a reservoir to a tube system external of the reservoir and in flow communication with the reservoir, wherein the solvent is recovered by a) conveying shaped objects in the form of spheres through the closed circuit path of flow in a direction from an upper end to a lower end of the reservoir and then through the tube system and then back to the upper end of the reservoir, b) collecting the spheres on a perforated plate in the reservoir between the upper and lower ends to form a packing in the reservoir, c) transferring the spheres by means of a transfer lock mounted to the perforated plate to controllably convey the spheres from the plate to the tube system, d) cooling the spheres by passing the spheres through a heat exchanger in the tube system externally of the reservoir, e) feeding a solvent containing waste gas through an inlet into the lower end of the reservoir below the perforated plate, f) conveying the waste gas in a direction countercurrent to the direction of flow of the spheres, g) passing the waste gas through the perforated plate and into contact with the cooled spheres, h) freezing out the solvents contained in the waste gas to solidify the solvents, i) permitting the solidified solvents to fall downwardly in the reservoir below the inlet of the waste gas;
- j) melting the solvents in the lower end of the reservoir by means of the lower end having a higher temperature than the upper end, k) draining the melted solvents from the lower end of the reservoir below the waste gas inlet, and l) discharging the cold purified waste gas from the upper end of the reservoir.
Dependencies are inferred from the claim text.