GB2078133A - Reverse osmosis unit-degasifier system - Google Patents
Reverse osmosis unit-degasifier system Download PDFInfo
- Publication number
- GB2078133A GB2078133A GB8117972A GB8117972A GB2078133A GB 2078133 A GB2078133 A GB 2078133A GB 8117972 A GB8117972 A GB 8117972A GB 8117972 A GB8117972 A GB 8117972A GB 2078133 A GB2078133 A GB 2078133A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- degasifier
- reverse osmosis
- eductor
- low pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001223 reverse osmosis Methods 0.000 title claims abstract description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 66
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 19
- 239000002351 wastewater Substances 0.000 claims abstract description 16
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 14
- 239000012528 membrane Substances 0.000 claims description 16
- 239000007788 liquid Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 claims 1
- 239000002253 acid Substances 0.000 description 8
- 230000003134 recirculating effect Effects 0.000 description 3
- 238000007872 degassing Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005188 flotation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003925 fat Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
- B01D61/08—Apparatus therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2311/00—Details relating to membrane separation process operations and control
- B01D2311/08—Specific process operations in the concentrate stream
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Nanotechnology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physical Water Treatments (AREA)
- Degasification And Air Bubble Elimination (AREA)
Abstract
The high pressure waste water from a reverse osmosis unit (RO) is conveyed to an eductor where it creates a source of low pressure for operating a degasifier that removes carbon dioxide from the water treated by the reverse osmosis unit. <IMAGE>
Description
SPECIFICATION
Reverse osmosis unit-degasifier system
The invention relates generally to the treatment of water by reverse osmosis units, and particularly to those units that require degasification to remove carbon dioxide.
Reverse osmosis membranes are frequently used to treat water to remove certain impurities.
The elements making up a reverse osmosis membrane require that water fed to the membrane have a pH below 8.5, otherwise they rapidly lose their capacity to function. In order to achieve the desired pH, water fed to the membrane is often treated by an acid to lower the pH prior to feeding the water to the unit. The combination of acid and water, however, may lead to the generation of carbon dioxide in the water.
Since reverse osmosis membranes are permeable to carbon dioxide, the carbon dioxide will remain in the water passed through the unit.
The carbon dioxide, which is undesirable, may be removed by sending the carbon dioxide-loaded water through a degasifier, but this ordinarily requires the expenditure of energy to operate the degasifier. The degasifier operates by passing the water through a tank where the carbon dioxide in the water rises to the top of the tank where a space is maintained. The carbon dioxide is removed from this space.
In U.S. Patent No. 3,917,526 (Jennings) the stream from a membrane is used to effect the eduction removal of foam from the top of a flotation stage in a process for removing suspended solids, fats, oily wastes, etc. from a liquid stream. The liquid stream passes through the flotation system before entering the reverse osmosis membrane system in the arrangement shown in that patent.
It is an object of the invention to provide for a reverse osmosis unit and degasifier system in which less energy is required for operation.
According to one aspect of the invention a reverse osmosis membrane unit and degasifier system comprises:
a reverse osmosis unit having an inlet, an outlet for water passed through the reverse osmosis membrane, and an outlet for waste water;
a carbon dioxide degasifier having an inlet for receiving said passed water and means for degasifying said water, said degasifying means responsive to a source of low pressure;
an eductor means for producing low pressure in response to a flow of liquid;
means for conveying said waste water from said reverse osmosis unit to said eductor means for producing low pressure; and
means for connecting said low pressure to degasifier.
The invention also provides a method of degasifying water passed through the reverse osmosis membrane of a reverse osmosis unit, comprising the steps of:
providing a degasifier having an inlet for receiving water to be degasified and a low pressure chamber for removing gas from said degasifier;
conveying the output of said reverse osmosis unit to said degasifier;
providing an eductor for producing low pressure in response to a flow of liquid;
conveying the waste water from said reverse osmosis unit to said eductor to produce low pressure in said eductor in response to the flow of waste water; and
connecting said eductor to said degasifier low pressure chamber.
The eductor produces a low pressure that sweeps a carbon dioxide degasifier to which water treated by the reverse osmosis unit is conveyed.
The water to operate the eductor and the water to be treated by the degasifier operated by the eductor leave the reverse osmosis unit substantially at the same time so that the power source (reverse osmosis unit waste water) is available as soon as the water entering the degasifier can use it.
A specific embodiment of the invention in its method and apparatus aspects will now be described by way of example and not by way of limitation with reference to the accompanying diagram which shows a portion of a water treatment system including a reverse osmosis unit (RO unit) having a permeable membrane, and a degasifier forming a system according to the invention. Located on the water supply line to the inlet of the RO unit is a tank holding a supply of acid that is connected by a feed to the water supply line. Further along the supply line is a pump for creating the high pressure needed to operate the RO unit. The RO unit has two outlets, a waste water outlet for removing from the unit untreated water (still at high pressure), and a treated water outlet, for removing water treated by the RO unit.
The degasifier includes a tank that ordinarily, during the process, has a lower portion filled with water and an upper portion free of water. A degasifier inlet is connected by a conduit to the
RO unit treated water outlet for conveying that water to the degasifier. An air supply duct leads to the upper portion of the degasifier tank, a filter being located in the duct between the air intake and the tank. An eductor has a low pressure chamber that is connected to the upper tank portion by an air conduit, opposite the air supply connection to the chamber, so that air entering the chamber from the air supply can be swept across the top of water in the tank before being discharged via the eductor.The degasifier includes a recirculating pump connected to an outlet at the bottom of the tank for recirculating water in the tank to the top of the tank where it can be sprayed through a nozzle into the tank's upper chamber.
Said pump might also serve as the distribution pump for the processed water. An outlet for withdrawing degasified water is located at the bottom of the tank. Another configuration omits the air inlet and allows the eductor to draw a slight vacuum which reduces the dissolved gases from the purified water in the tank.
The eductor is connected to the waste water outlet of the RO unit. This waste water is ejected from the RO unit at a very high pressure. Rather than discarding this energy, the waste water outlet is connected by a conduit to the eductor and the water pressure is used to operate it.
In the operation of the system, raw water is fed to the RO unit for treatment. If the pH value of the water is too high for non-destructive use of the RO unit membrane (e.g. a pH value exceeding 8.5) or the salts in the water leave scale deposits, acid is fed to the raw water to lower its pH value. For example, raw water having a pH of 8.0 might be fed into the system at a rate of 10 gallons per hour. An acid such as H2SO4 would be added to the water from the acid holding tank, reducing the pH to a value of approximately 6.0. The pump feeds this water, treated with acid, to the inlet of the RO unit. Since the RO unit needs high pressure water input for operation, the pump increases the water pressure to about 200 psi.
As a result, with water entering the RO unit at 10 gph and a pressure of 200 psi, eventually there is a discharge outlet at a rate of 5 gph, and a discharge of waste water at the other discharge outlet at a rate of about 5 gph, and at a pressure of 40 psi.
The water treated by the RO unit passes through the conduit to the intake of the degasifier tank. The acid, H2S04,added to the water to lower its pH, has resulted in the generation of carbon dioxide. The presence of CO2 in the water is, naturally, undesirable. The degasifier represents a common technique for removing the CO2. The CO2 in the water brought into the degasifier tank rises to the surface and occupies the upper portion of the tank that is free of water. The effect is enhanced by recirculation of water in the tank by the recirculating pump. Water is brought up to the top of the tank and is sprayed through the nozzle in the top of the tank, where the water gives up its
CO2 content.
The low pressure air chamber is connected to the upper portion of the tank. It sucks the carbon dioxide that has settled there out of the tank. The air inlet gives a source of air to the upper chamber so that this sweep of the upper chamber is possible. Water free of CO2 is conveyed out of the tank inlet.
As explained above, the high pressure RO unit waste water discharge creates in the eductor low pressure air chamber a pressure of about~10 psi.
This water pressure is available to operate the eductor as soon as the RO unit itself begins to operate. Therefore there is no delay in starting up the system. Treated water for the degasifier leaves the RO unit at the same time that waste water'to operate the eductor leaves the RO unit.
The advantage of the described embodiment is that it conserves energy that would otherwise be discarded. It encourages the use of acid treatment of raw water, to preserve the RO unit membrane, because it makes the use of a degasifier more feasible. It provides an integrated system that requires no start-up auxiliary steps or temporary inoperability of parts of the system: as soon as water is being brought to the tank for degasification, water (from another source) is being brought to the eductor to operate the degasifier.
Claims (3)
1. A reverse osmosis membrane unit and degasifier system comprising:
a reverse osmosis unit having an inlet, an outlet for water passed through the reverse osmosis membrane, and an outlet for waste water;
a carbon dioxide degasifier having an inlet for receiving said passed water and means for degasifying said water, said degasifying means responsive to a source of low pressure;
an eductor means for producing low pressure in response to a flow of liquid;
means for conveying said waste water from said reverse osmosis unit to said eductor means for producing low pressure; and
means for connecting said low pressure to degasifier.
2. A method of degasifying water passed through the reverse osmosis membrane of a reverse osmosis unit, comprising the steps of:
providing a degasifier having an inlet for receiving water to be degasified and a low pressure chamber for removing gas from said degasifier;
conveying the output of said reverse osmosis unit to said degasifier;
providing an eductor for producing low pressure in response to a flow of liquid;
conveying the waste water from said reverse osmosis unit to said eductor to produce low pressure in said eductor in response to the flow of water water; and
connecting said eductor to said degasifier low pressure chamber.
3. A reverse osmosis unit and degasifier system substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16133980A | 1980-06-20 | 1980-06-20 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2078133A true GB2078133A (en) | 1982-01-06 |
| GB2078133B GB2078133B (en) | 1983-09-21 |
Family
ID=22580796
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8117972A Expired GB2078133B (en) | 1980-06-20 | 1981-06-11 | Reverse osmosis unit-degasifier system |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1164356A (en) |
| GB (1) | GB2078133B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0226432A2 (en) * | 1985-12-10 | 1987-06-24 | Albany International Corp. | Removal of dissolved gases in liquid separation systems |
| JPS62273095A (en) * | 1986-05-21 | 1987-11-27 | Japan Organo Co Ltd | Water treatment plant |
| EP0436098A2 (en) * | 1989-12-13 | 1991-07-10 | Fresenius AG | Process for degassing purified water obtained by reverse osmosis and reverse osmosis system for carrying out said method |
| US8617398B2 (en) | 1996-08-12 | 2013-12-31 | Debasish Mukhopadhyay | Method for high efficiency reverse osmosis operation |
| US8758720B2 (en) | 1996-08-12 | 2014-06-24 | Debasish Mukhopadhyay | High purity water produced by reverse osmosis |
| US11112127B2 (en) | 2016-07-01 | 2021-09-07 | Spiro Enterprises B.V. | Gas separator |
-
1981
- 1981-06-11 GB GB8117972A patent/GB2078133B/en not_active Expired
- 1981-06-22 CA CA000380331A patent/CA1164356A/en not_active Expired
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0226432A2 (en) * | 1985-12-10 | 1987-06-24 | Albany International Corp. | Removal of dissolved gases in liquid separation systems |
| EP0226432A3 (en) * | 1985-12-10 | 1988-07-27 | Albany International Corp. | Removal of dissolved gases in liquid separation systems |
| JPS62273095A (en) * | 1986-05-21 | 1987-11-27 | Japan Organo Co Ltd | Water treatment plant |
| EP0436098A2 (en) * | 1989-12-13 | 1991-07-10 | Fresenius AG | Process for degassing purified water obtained by reverse osmosis and reverse osmosis system for carrying out said method |
| EP0436098A3 (en) * | 1989-12-13 | 1992-03-04 | Fresenius Ag | Process for degassing purified water obtained by reverse osmosis and reverse osmosis system for carrying out said method |
| US8617398B2 (en) | 1996-08-12 | 2013-12-31 | Debasish Mukhopadhyay | Method for high efficiency reverse osmosis operation |
| US8641905B2 (en) | 1996-08-12 | 2014-02-04 | Debasish Mukhopadhyay | Method for high efficiency reverse osmosis operation |
| US8758720B2 (en) | 1996-08-12 | 2014-06-24 | Debasish Mukhopadhyay | High purity water produced by reverse osmosis |
| US9073763B2 (en) | 1996-08-12 | 2015-07-07 | Debasish Mukhopadhyay | Method for high efficiency reverse osmosis operation |
| US9428412B2 (en) | 1996-08-12 | 2016-08-30 | Debasish Mukhopadhyay | Method for high efficiency reverse osmosis operation |
| US11112127B2 (en) | 2016-07-01 | 2021-09-07 | Spiro Enterprises B.V. | Gas separator |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2078133B (en) | 1983-09-21 |
| CA1164356A (en) | 1984-03-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |