Gas separation – Means within gas stream for conducting concentrate to collector
Patent
1991-08-06
1993-03-16
Spitzer, Robert
Gas separation
Means within gas stream for conducting concentrate to collector
55189, B01D 5322
Patent
active
051940744
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a device for continuously purifying the waste gases from a vacuum unit.
Many processes in which harmful gases are formed are carried out under a vacuum. To maintain the vacuum, a vacuum pump creates a steady stream of material, which also contains the harmful gases, in the direction of the atmosphere. The waste gas stream from the vacuum pump must therefore be purified. Condensation systems and absorption systems are in use for this purpose.
It is known to use gas permeation membranes for purifying gases. These are thin films whose resistance to the passage of the harmful gases to be separated out of the waste gas is smaller than that for the process gas (for example air). The gas permeation membrane is arranged in a membrane module in such a way that it separates a flow path for the waste gas from a space which is to receive the gases, termed permeate, penetrating the membrane. For carrying out the purification, it is necessary to create a pressure gradient from the waste gas side to the permeate side of the membrane module. It is known (German Offenlegungsschrift 3,806,107) to use one or more special pumps for this purpose, which are used in addition to the delivery pump of the unit.
The gas permeation technique has not been applied to vacuum units, because the expense on equipment and operation appeared to be unduly great in view of the large volumes to be dealt with in the case of vacuum. It was overlooked in this connection, however, that the use in vacuum units provides an otherwise non-existing possibility for reducing the expense on equipment and operation.
Accordingly, the solution according to the invention comprises forcing the waste gas stream by means of the vacuum pump of the vacuum unit through the membrane module and connecting the permeate side of the membrane module to the suction side of the same vacuum pump.
Expressed briefly, the vacuum pump of the vacuum unit itself is used for generating the pressure difference which is required for the operation of the gas permeation membrane module. As a result, the cost of several separate pumps is saved. Moreover, the invention has the result that, due to the recycle of the permeate into the waste gas stream, the pollutants are concentrated therein, so that the pollutant separation and/or purging can be carried out effectively. When the vacuum pump or the membrane module is mentioned here for the sake of simplicity, this is meant to include the case where several vacuum pumps or membrane modules are provided in a functional unit.
In the device according to the invention, a small part of the suction capacity of the vacuum pump is utilised for operating the gas permeation membrane module. Depending on the pollutant concentration and the nature of the membrane, this part can amount to, for example, 5-30%. As a result, recycling of the pollutants in the form of a permeate stream at high loading is achieved. They can be taken out of the gas circulation formed between the vacuum pump and the membrane module in any desired manner, in order to be destroyed or processed in another way. For example, a part of the permeate stream recycled from the membrane module to the vacuum pump can be continuously branched off. A condenser which condenses the pollutants out of the gas circulation can also be provided in the latter. Since the pollutant concentration in the permeate stream is very high, the condensation can be carried out particularly efficiently in a condenser arranged there or in the vacuum pump. Especially if a vacuum pump of low condensate tolerance is used, the pollutants are advantageously condensed out of the permeate stream on the suction side before entry into the vacuum pump and discharged. However, it can also be advantageous to provide a condenser in the waste gas stream between the vacuum pump and the membrane module, since the pollutant concentration is increased also in this region of the permeate circulation according to the invention.
If there is a possibility of pollutants being formed even on starting the vacuum
REFERENCES:
patent: 4675030 (1987-06-01), Czarnecki et al.
patent: 4772295 (1988-09-01), Kato et al.
patent: 4931070 (1990-06-01), Prasad
patent: 4955998 (1990-09-01), Ueda et al.
patent: 4994094 (1991-02-01), Behling et al.
patent: 5034025 (1991-07-01), Overmann, III
patent: 5051188 (1991-09-01), Spiske et al.
SIHI GmbH & Co. KG
Spitzer Robert
LandOfFree
Device for continuously purifying the waste gases from a vacuum does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for continuously purifying the waste gases from a vacuum , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for continuously purifying the waste gases from a vacuum will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-349222