KR20040039312A - Oil dehydrator - Google Patents

Abstract

The present invention provides a method and apparatus for removing glass, emulsified or dissolved water from a low boiling liquid such as oil. Low boiling liquids are removed by contacting the liquid stream with the semipermeable membrane. The membrane divides the separation chamber into a supply surface through which a fluid stream is supplied and a transmission surface through which water is removed. The permeate side of the chamber is maintained at low partial pressures of water through vacuum or using sweep gas.

Description

Oil Dehydrator {OIL DEHYDRATOR}

Oil is used in lubrication and hydraulic systems. If water is present in the oil, this adversely affects such a system, such a system and its operation. Corrosion if water enters the lubrication or hydraulic system; Oil oxidation, chemical consumption and fatigue life are known to occur. These adverse effects are due directly to the water present in free, emulsified or dissolved form.

Thus, numerous studies have been conducted to remove water from oil to provide optimum performance of lubrication and hydraulic systems. Devices and systems used to remove entrained water include settling tanks or settling basins, centrifuges, absorption filters, and vacuum dewatering oil clarifiers. However, they have serious problems with either moisture removal, ease of operation, capital cost or operating cost, as discussed.

Settling tanks remove most of the "free" moisture from the oil based on their density and gravity settling differences. In order to effectively remove "glass" moisture, the settling tank requires a long storage time and an effective amount of floor space. However, they are not effective for the separation of oil-water emulsions and are not possible to remove dissolved water.

Centrifuges accelerate the gravity precipitation of water from oil by applying centrifugal force to the fluid to effectively increase gravity. Centrifugation is effective to remove free moisture from oil. However, these centrifuges are generally expensive and have the limitations of separating oil-water emulsions. They cannot remove the dissolved water from the oil.

Absorption filters use special filter media that absorb water from oil. As the water is absorbed, the mayer expands to limit the flow rate, causing a pressure drop through the filter. Once the pressure drop reaches a predetermined level, the absorbent filter must be removed, discarded and replaced with a new filter. These absorption filters are effective in removing water, but their effects are limited in removing emulsified or dissolved water from oil. In addition, the absorption filter has only limited capacity for water. Therefore, they must be replaced once saturated with water. Thus, they can typically be used only when trace amounts of water are present. In application, when the water concentration is high, the continuous replacement cost of the absorption filter becomes very high.

Various vacuum dewatering oil purifiers have been used for oil dewatering. They generally operate on the principle of vacuum distillation, transfer of large amounts of moisture from oil to dry air, or a combination of the two.

In vacuum distillation, vacuum is applied to lower the boiling point of water. For example, the boiling point of water is 100 ° C (212 ° F) at 1013 mm H ₂ O (29.92 "Hg) pressure (standard atmospheric pressure), but only 50 ° C (122) at 100 mm H ₂ O (about 26" Hg vacuum). ℉). By applying a significant vacuum to the temperature of the oil, water in the oil evaporates from the oil to low pressure (vacuum) and dewaters the oil.

Flowing oil into a contacting vessel having a vacuum applied thereto with a vacuum pump is a typical means by which such water removal is achieved. A large surface area ratio of oil to volume is desirable to minimize the water vaporization ratio in a given vessel. This can be done by flowing the oil by methods well known in the art of structured packing, random packing, cascade plates, spin disks or other vacuum distillation and contacting. Typically the oil enters the top of the contactor, gravity down on the packing and disperses into a fairly thin film. Collected at the bottom of the vessel pumped out by the oil pump. Examples of these include US Patent No. 4,604,109 to Koslow and US Patent No. 5,133,880 to Landquist et al. In order to reduce the amount of oil required, the oil may be heated.

When a vacuum is applied to lower the water boiling point, the rate of water removal is high. In addition, heat is applied to increase the rate of water removal. However, care must be taken not to apply too much heat and / or vacuum. This is because even low molecular weight hydrocarbons in oils volatilize below their boiling points as temperature and / or vacuum increase. It should be understood that it is also removed with any liquid having a lower boiling point than water. Its application is both preferred and undesirable.

High volume transfer systems use similar contact vessels. However, rather than relying on distillation for the removal of water, dry air or gas passes continuously upwards back across the downstream oil. Water molecules in the oil will migrate to the corresponding dry air through a concentration gradient. The wet air is drawn out of the contactor by a vacuum pump or a dryer and exhausted to the atmosphere. It is not necessary to heat the oil above the boiling point of water to vaporize the water. Thus, it may be carried out with lower heat and / or vacuum than vacuum distillation systems to remove water with mass transfer systems.

Vacuum distillation and mass transfer systems remove glass, emulsified and dissolved water, while they have a general purpose membrane disadvantage. In both systems, liquid level control is used in the vessel to ensure that the oil level does not go low and the oil pump does not dry out. In addition, the liquid level control must ensure that the oil level does not become high so that the vacuum vessel is filled with oil. This lowers or eliminates the water control efficiency in the vessel, allowing the oil to fill the vessel completely and overflowing into the vacuum pump.

In addition, the vacuum purifier causes foaming in the container as the water vaporizes in the oil. This foam has a specific gravity lower than that of oil, and causes the dysfunction of liquid level removal, and also causes deterioration of purifier performance.

Due to the nature of using heaters, controllers and pumps, purifiers are composed of very complex parts. In addition, the type of packing used, the viscosity of the oil and the air flow rate limit the flow rate through the contactor vessel. This usually requires the use of very large vessels used for flow rate amounts. When completed with the required oil pumps, vacuum pumps, heaters, controllers, electrical panels and junctions, this system becomes too large and expensive. The maintenance and operation costs are usually very high due to the large number of components and the complexity of these systems.

Due to their ability to remove glass, emulsified or dissolved water from oil, vacuum dehydration oil purifiers have become a preferred method of removing water from oil. However, drawbacks with vacuum oil purifiers have prevented these purifiers from being universal and / or practical in most of the lubrication or hydraulic systems. Because of their relatively large side and cost, they are not practical for use in mobile devices because they are limited to non-moving stationary applications.

Because of their high capital cost, they cannot be permanently installed in the system unless the system is quite large and expensive lubrication or hydraulic system. Instead, they divide one into several systems and use one to refine the oil for a short time in one machine or reservoir, and then move it back to another machine or the like. However, when a purifier is used in this way, the oil in the machine that is not connected to the purifier is contaminated with water. This oil remains contaminated until the purifier is recombined and dehydrated again. Thus, one of ordinary skill in the art continued to study improved methods for removing oil from water. Applicants have worked on membrane based systems.

Membrane foundation systems are being used to remove water from organic systems. However, the presence of voids or defects in the membrane used for this purpose should be recognized that the hydraulic permeation of oil occurs in the permeate side. This situation leads to loss of oil. In addition, non-volatile oils cover the permeate side of the membrane to contaminate the membrane and reduce the efficiency in the water that permeates.

Taylor, US Pat. No. 4,857,081, discloses a method of dehydrating a hydrocarbon or halogenated hydrocarbon gas or liquid. This method is based on cuproammonium regenerated cellulose membranes. It is known in the art that a copper ammonium regeneration membrane has a structure in which passages or pores are connected to each other (US Patent No. 3,888,771 to Isuge et al.). These membranes are also said to have a pore distribution of 10 to 90 ms with an average of 30 ms (US Patent No. 3,888,771 to Isuge et al., US Patent No. 5,192,440 to Sengbusch). The mechanism for separating water from the liquid organic phase via this copper ammonium regenerated cellulose is a dialysis mechanism. The permeable material permeates the membrane as a liquid. Since the membrane has voids, it allows hydraulic transmission through it. The water soluble material is permeable through it. Since the oil has a limited solubility in water, it cannot be used for oil dehydration.

Even if Taylor is satisfied with oil dehydration, Taylor's structure has its own drawbacks. The molecular structure of the regenerated cellulose membrane is maintained in the presence of moisture. When moisture is removed from the hydrophilic membrane, the pores are subjected to large capillary stresses that shrink and form cracks in the membrane. Since the membrane has pores of various sizes, capillary stresses formed during drying are subjected to differential stress through the membrane microstructure. This differential stress is known to cause cracks or "defects" in the membrane. If such a membrane is used to dewater the closed system, the moisture in the membrane will likely be lost. This results in cracks or "defects" as described above. These "defects" will cause hydraulic movement of oil through the membrane.

US Pat. No. 5,182,022 to Pasternak et al. Discloses an evaporation method for dehydration of ethylene glycol. Ethylene glycol is completely miscible with water, and is characterized by the application of evaporation in which the mixture to be separated is completely miscible. The sulfonated polyethylene resin membrane used allows a substantial amount of ethylene glycol to be permeated. This permeation of ethylene glycol is due to hydraulic permeation through deficiencies (see definitions below), which is apparent to those of ordinary skill in the art that what is present in the identification layer. This invention does not require an identification layer without defects because loss of non-aqueous phase is tolerated. This is not the case of oil dehydration in lubrication and hydraulic systems.

U.S. Patent No. 5,464,540 to Friesen et al. Discloses a method for removing components from a liquid feed mixture via an evaporation method. Sweep streams in Prizen et al. Should not be removed and consist of components of the feed stream introduced into the module in the gas phase. In lines 5 to 8 of the Prizen et al. Patent, it is assumed that this method can be used to dehydrate oils such as sesame oil and corn oil. However, in the examples of the patent, Prizene et al. Only provide performance data regarding the dehydration of high boiling organic compounds, large amounts of sesame oil and corn. Prizene in particular provides examples of dehydration of acetone, toluene and ethanol. Thus, it is clear that Prizen did not recognize or suggest the need for a non-porous membrane that is free of dehydration of this kind of oil (described below). In addition, one of ordinary skill in the art is suspicious of the possibility of providing a swept stream of corn oil or sesame oil vapors.

Zhou, US Pat. No. 5,552,023, discloses a membrane distillation technique for dehydration of ethylene glycol. This method uses a porous membrane. This is not attractive for oil dehydration because the porous support wets and permeates the fluid hydraulically.

US Pat. No. 6,001,257 to Braton et al. Discloses a zeolite membrane that is substantially free of dehydration for various liquid dehydration purposes. The use of zeolite membranes is critical to the function of the device, as described in Braton Patent 4, lines 12-15, which can be used to separate two liquids passing through only one liquid through the zeolite membrane. Zeolite membranes use a zeolite type of material known as molecular sieves and contain a network of channels formed of silicon / oxygen tetrahedrons connected via oxygen atoms. In line 2, lines 46 to 49 indicate that this substance does not limit the scope of "substantially" and that there should be "substantially deficient" without the implied meaning of "defect". Such a membrane cannot be used for dehydration of oil because the presence of the defect described below occurs because hydraulic permeation of oil occurs on the permeate side.

In the context of the present invention, as used throughout the specification, the following terms are attempted to suggest the meanings described below:

Justice:

As used herein, a "defect" is used to indicate a hole through a membrane of sufficient size to allow hydraulic transmission of low volatility liquid through the membrane.

Thus, “no defect” refers to a membrane without a hole of sufficient size to allow hydraulic penetration of liquid through the membrane, instead of restricting the passage of material through the membrane into the solution. Hydraulic permeation of the oil is likely to occur when there are continuous holes in the membrane that are greater than or equal to the molecular size of the oil. It is expected that the molecular size of the oil molecules is greater than 5-10 kPa. However, since the oil consists of fractions of different molecular sizes, the exact value will depend on the chemical composition of the particular oil being dehydrated. Thus, the defect-free membrane is limited to having pores of diameter smaller than the molecular size of the oil molecules.

"Non-porous" means a membrane that does not contain voids, which are generally referred to as at least the molecular size pores of an oil molecule, which is expected to be greater than 5-10 kPa, as described above, but with certain types of oil being dehydrated Depends absolutely on.

While the defect free membrane used herein is necessarily nonporous, the nonporous membrane used herein need not necessarily be free of defects. In theory, the non-porous membrane would be free of defects, that is, without the aforementioned defects. However, in practice this is not the case. For example, Pinau, I. And Koros, W., "Gas-Permeation Properties of Asymmetric Polycarbonate, Polyestercarbonate, and Fluorinated Polyimide Membranes Prepared by the Generalized Dry-Wet Phase Inversion Process", J. Applied Polymer Science Vol., 46, 1195-1204 (1992)) and Pesek, S, "Aqueous Quenched Asymmetric Polysulfone Flat Sheet and Hollow Fiber Membranes Prepared by Dry / Wet Phase Separation", Dissertation submitted to The University of Texas at Austin ( 1993) defined a defect-free gas separation membrane as a membrane having a selectivity of 75% to 85% of a high density film. Membranes with a selectivity of 85% may indicate that they may contain a significant number of defects that allow hydraulic penetration of the oil.

Consider a membrane consisting of a polysulfone selective layer supported by a negligible resistance infrastructure. At 35 ° C. polysulfone has an O ₂ / N ₂ selectivity of 1.5 barrer (Membrane Handbook) with an oxygen permeability of 5.6. Consider the thickness of the polysulfone selective layer of 700 mm 3. This thickness is typical of commercial membranes. Thus, the selective layer permeation of oxygen is 20 GPU and the permeation of nitrogen is 3.57 GPU. According to Pinau and Koros (1992), this polysulfone membrane would be considered free of defects if the O ₂ / N ₂ selectivity was 85% of the high density film, or 4.76 in this case. According to the definition of the present invention, this membrane contains no defects. If the defect is small enough, the flow through the defect will be controlled by Knudsen diffusion. If the defect is large, the flow through the defect will be refluxed (or viscous) and will follow the Hagen-Poiseuille law. The table below shows the number of different sized defects resulting in an O ₂ / N ₂ selectivity of 4.76 for 1 m 2 polysulfone module.

Knudsen diffusion through deficiencies in select layers Defective particle diameter 25 50 100 Number of defects 1.22E + 11 1.53E + 10 1.91E + 9 Surface porosity (defect area / total area) 6.1E­7 3.0E­7 1.5E­7

Reflux through deficiency in select layers, pressure applied by 1 psig Defect particle size (m) 0.5 One 2 Number of defects 39700 247 15 Surface porosity (defect area / total area) 7.8E­10 1.9E­10 4.9E­11

The average size of the defects listed in the table above is large enough to allow hydraulic permeation of oil through the defects and is provided to commercial oil dewatering modules. However, for applications such as gas separation, the presence of defects only degrades the efficiency of separation and thus cannot be provided in commercial modules.

In theory, the nonporous membrane would be free of defects, that is, without defects as described above. In practice, however, this is not the case. As practiced and appreciated by those of ordinary skill in the art, membranes considered nonporous may allow hydraulic permeation below certain factors to increase their gas selectivity from the internal selectivity of the high density film up to 85%. It would be enough to lower and still be considered a nonporous membrane. Thus, such membranes are substantially quite small, but still have a significant number of voids. The substantial number of voids allowed in a "non-porous" membrane is related to the size of the pores and the nature of the material separated by the membrane. As used herein, a defect-free membrane refers to the nonporous membrane described above, which is nonporous, and does not refer to the nonporous membrane of the term generally used in the art. For the successful practice of the present invention, the term must be "nonporous" and "free of defects" as defined herein.

"Oil" is used to refer to a low boiling point compound. Oils typically consist of many fractions of different molecular weights and molecular structures in the mixture.

"Semi-permeable" refers to a membrane that is permeable to certain materials but resists the movement of other materials. In addition, such a membrane is also referred to as a discriminating membrane.

"Wetting" refers to the spread of a liquid on a surface.

"Fouling" is the resistance to mass transfer through unwanted action, such as filling the porous substructure of a membrane with oil or covering the sweep side of the membrane with oil.

The present invention relates generally to the lubrication and hydraulic industry, and more particularly to apparatus and methods used for removing glass, emulsified or dissolved water from oils, more generally from low volatility liquids.

1 is a perspective view of a membrane structure used in the present invention.

2 is a perspective view of a membrane variant useful in the present invention.

3 is a perspective view of another modified membrane useful in the present invention.

4A is a plan view of a plurality of hollow fiber membranes of a woven mat, as shown in FIG.

4B is a longitudinal cross-sectional view taken in the direction of the arrow, along line B-B in FIG. 4A.

4C is a schematic view of the mat shown in FIG. 4B after winding in a spiral.

FIG. 4D is a perspective view of two hollow fiber semipermeable membrane structures after being wound in a spiral, as shown in FIG. 3.

5 is a schematic view of the structure shown in FIG. 1 after winding in a spiral.

6 is a schematic of an exemplary membrane separation method embodying the present invention wherein water is removed by a vacuum pump means.

7 is a schematic view of a variant of the separation method shown in FIG. 6 in which water is removed by means of a swept gas stream.

8 is a schematic representation of a variant of the separation method shown in FIG. 6 in which the membrane is protected from contaminants in the feed stream by upstream filter means.

9 is a front view of a hollow fiber embodying the configuration of the present invention in which the feed flows into the inner diameter of the fiber.

10 is a front view of a cavity fiber embodying the configuration of the present invention in which the feed flows out of the fiber.

11 is a front view of a hollow fiber embodying the configuration of the present invention in which the feed flows out of the fiber and the water is removed in countercurrent to the discharge oil. The oil is extracted by the puncture core.

12 is a front view of a cavity fiber embodying the configuration of the present invention wherein water is removed by the sweep gas.

FIG. 13 is a perspective view of a modification of the configuration shown in FIG. 1 in which the membrane is a skin formed entirely. FIG.

14 is a fragmentary end front view of the configuration shown in FIG. 13.

FIG. 15 is a perspective view of a modification of the configuration shown in FIG. 3, in which the membrane is a skin formed entirely. FIG.

16 is a fragmentary end front view of the configuration shown in FIG. 13.

Best Mode for Carrying Out the Invention

The specific drawings and the specific apparatus and methods described below are representative examples of the inventive concepts defined in the appended claims. Accordingly, specific areas and other physical properties related to the embodiments known herein are not limited to this range unless explicitly stated in the claims.

Before describing the preferred embodiment of the present invention, pages 3-15 of the Membrane Handbook published by Van Nostrand Reinhold in 1992 and pages 56-61 of the first edition of the Handbook of Industrial Membranes 1995 have been revised here. It is inserted.

The present invention relates to apparatus and methods useful for reliably removing water or high volatile solvents from a wide range of low volatile liquids. Low volatility liquid is defined as a liquid having a boiling point higher than the standard boiling point of water (100 ° C.), so water will belong to a high volatility liquid. It should be noted that components that exhibit low volatility in the pure state do not ideally react in the mixture. This can lead to significantly higher evaporation rates of the components in the mixture than expected of pure component volatility. Preferably the present invention relates to the separation of water from oil.

More specifically, the method of dehydrating oil consists of the following steps: contacting one side of a nonporous, impermeable semipermeable membrane with a liquid vapor containing at least oil and water, wherein the membrane feeds the separation chamber. Dividing the feed mixture into the feed side and the permeate side through which the water exits; Maintaining a partial chemical potential gradient to water such that water preferentially permeates through the membrane from the feed side to the permeate side; Removing water that has permeated from the permeate side; Remove the dehydrated oil from the feed side of the membrane. "Chemical potential gradient" is also referred to as "active gradient" or "partial pressure gradient". By "partial pressure gradient" is meant the difference between the water vapor pressure on the permeate side and the equilibrium water vapor pressure corresponding to the water concentration in the oil.

An apparatus for dehydrating oil includes at least one supply surface and one permeate surface inside the vessel; At least one feed surface direction inlet opening; At least one feed surface direction outlet opening; And a container containing at least one non-porous, semi-permeable, defect-free membrane inserted into the container in a form that can be divided into at least one feed surface direction exit opening. Such a device makes it possible to flow the oil-water mixture through the inlet opening and to make contact with at least one side of the semipermeable membrane; Maintaining a partial chemical potential gradient for water such that water preferentially permeates through the membrane from the feed side to the permeate side; Removing water that has permeated through the outlet opening from the permeate surface; It is possible to remove the dehydrated oil through the opening from the feed side of the membrane.

Given a surface suitable for separation, the membrane may be in any form or shape. Conventional examples include self-supporting films, hollow fibers, synthetic sheets, synthetic hollow fibers. The co-fiber membranes are bottled or otherwise arranged so that the fibers are nominally parallel to each other. The fibers of the synthetic co-fiber membrane or the co-fiber membrane will be spirally wound or twisted. Otherwise, the fibers may also be woven into the mat. In the case of membranes consisting of mats of flat sheets or fibers, the sheets or mats will be spirally wound. The spacer will also separate the sheet or mat.

The membrane used consists of a support structure and at least in part a thin, defect-free, high-density, non-discriminating layer (also called "skin") and a support structure. In another embodiment, the fractionation layer will also self support; However, this is not necessary to carry out the invention. It is apparent to one of ordinary skill in the art that a dense, nonporous fractionation layer has defects on the fractionation layer. If this fractionation layer is used to separate a gas or liquid mixture, the deficiency results in indiscriminate transportation. In the case of the fractionation bed used to separate the gas mixture, the transport through the fractionation bed occurs as "solution-diffusion" while the transport through the defect occurs as Knudsen diffusion. Evidence is provided in Clausi Clausi, N., "Formation and Characterization of Asymmetric Polyimide Co-Fiber Membranes for Gas Separation," submitted to the University of Texas, Austin, 1998. When the fractionation layer containing the defect is used to separate the liquid mixture, indiscriminate hydraulic transport will occur through the defect. Hydraulic transport through the defect will allow liquid to permeate the permeate side of the membrane. Such indiscriminate transportation is satisfactory in some applications, but is undesirable for other uses.

An example of a defect-free, high density nonporous fractionation layer is the case of a solution dense membrane. The membranes above are known to those of ordinary skill in the art. Defective, high density, non-porous fractionation layers with commercially viable dehydration rates are obtained by solution casting of films of significantly thin thickness to allow for a desired dehydration rate. Potential defects can be removed by coating multiple layers of solution immersion polymers in an intermediate crosslinking step.

In certain instances of oil dehydration, permeation of oil to the permeate side will result in loss of oil from the system, making the dehydrator commercially unavailable and blocking the permeate side of the membrane. If the fractionation layer is supported on the permeate side, the hydraulic permeate oil will fill the porous support and block water transfer to block the membrane. In addition, if the oil is unlikely to evaporate or no evaporation occurs, the oil will not evaporate faster than the hydraulic permeability through the defect, and if there is a defect, it will irreversibly seal off the membrane and reduce the dehydration rate. Also, unless the membrane is completely free of defects, the sweep used on the permeate side to remove moisture will pass through the membrane and be removed from the clean oil. This bubbles up the oil and becomes undesirable.

The transport mechanism through the defect-free, high density nonporous fractionation layer is via "solution diffusion". For those of ordinary skill in the art, "solution-diffusion" is understood to mean desorption on the permeate side of the fractionation layer after dissolution of the material that has permeated into the fractionation layer and after diffusion through the fractionation layer. Oil and water are in the liquid phase towards the feed side of the membrane, while the permeated material is removed from the permeate side of the fractionation layer in vapor or gas phase. If the fractionation layer contains defects, hydraulic permeation through the fractionation layer will occur and transport liquid to the permeate surface. As discussed above, this situation can block the membrane and lead to oil loss of the system, making the product not commercially available.

To those of ordinary skill in the art, it is understood that excess evaporation refers to the separation of a liquid mixture that is fully miscible through a dense, nonporous fractional bed. In addition, excess evaporation is understood to mean that the components are permeated through the fractionation layer in a limited proportion and are removed from the permeate side with vapor. Furthermore, in the case of excessive evaporation of dehydration, non-aqueous transport to the permeate surface in the missing fractionation layer is not pessimistic. This is because the vapor pressure of the non-aqueous phase is high and does not evaporate easily. This is true even for low volatility components such as ethylene glycol, which, when mixed with water, may exhibit unexpectedly significant reactions compared to pure components.

Porous membranes, such as for microfiltration, ultrafiltration, and dialysis, are not suitable because the low volatility liquid penetrates the pores and blocks the membrane.

Preferred membranes include high density, nonporous polymeric films or asymmetric membranes having relatively dense fractionation layers or skins on one or both surfaces of the support structure. High density nonporous membranes are made either as "phase conversion" or "solution immersion". In the case of phase inversion, the polymer-solvent-nonsolvent system will be precipitated by solvent evaporation, solvent extraction or nonsolvent entry into the system. Phase conduction results in an inhomogeneous porous polymer with or without a symmetrical, non-porous polymer of high density. The high density, nonporous fractionation layer is formed by phase separation by appropriate selection of solvent-nonsolvent systems. In the case of solution dipping, the preferred polymer solvent system is gelled and then dried. Solution immersion polymers are typically not porous and are homogeneous films. In both cases, a high density nonporous film will be formed on another support structure. High density nonporous fractionation layers produced in two ways will have defects (US Pat. No. 4,230,463). Post-treatment methods to substantially reduce these fractional defects are also described in Henis and Tripodi (Henis, J. and Tripodi, M., "Synthetic Co-Fiber Membranes for Gas Separation: a Resistance Model Approach," J. Membr. Sci. (8). 233-245 (1981). The method for reducing the defect includes repeatedly covering the defective membrane until all the defects are removed. The secondary coating will be based on the same polymer as the original layer or on different polymers. A high density nonporous fractionation layer free of defects will be produced by solution immersion of a significantly thick homogeneous polymer film. It has also been demonstrated by Pfromm that ultra-thin, defect-free, high-density, nonporous fractional layers are produced (Pfromm, PH, 1994, published by the University of Texas at Austin, Texas, "Made from amorphous glass polymers." Gas transport and aging of one thin and thick film ").

For those of ordinary skill in the art, gas transport characteristics through high-density, non-porous, homogeneous polymer films without defects are typically considered to be an "essential" property of polymers (Clausi, 1998). For example, the intrinsic permeability of the polymer is independent of the thickness of the fractionation layer. If the fractionation layer is used to separate the gas mixture and the layer is a free standin film or composite on a support that has a very low transport resistance compared to the fractionation layer, the permeability of the particular mixture is also at Intrinsic properties of polymers. This ratio is called the intrinsic selectivity of the polymer for the particular gas component.

If the high density, nonporous fractionation layer does not exhibit "essential" selectivity for a particular combination of gases, this fractionation layer will contain defects. This is because the defect allows indiscriminate transport of the components to be separated. For those of ordinary skill in the art, this technique is commonly used to determine the presence of a missing fraction of a fractionation bed when the porous support hardly blocks flow (Clausi, 1998; US Pat. No. 4,902,422). The technique will be used to determine the presence of a defect regardless of the mechanism of formation of the fractionation layer. If it is confirmed that there is no deficiency in the fractionating bed, it will not allow the indiscriminate transport of gas or liquid. And in the case of liquid permeation, the permeate will be removed from the membrane by vapor.

A thin, high density nonporous fractionation layer would be a separation layer and would also be produced simultaneously and entirely with the support structure. The layer consists of different materials in the same material or composite form as the support structure. Synthetic membranes have a high density of layers that adhere to the support structure. The dense, nonporous fractional layer is produced later in the separation process. Such synthetic films, fibers or sheets are porous or nonporous. It is preferred that the sheet is flat, but not necessary to carry out the invention. The fibers, films or sheets will be immersed in one or more sides to separate the feed from the permeate side. The fractionation layer in this membrane will be the same or different from the support structure consisting of porous organic and inorganic polymers, porcelain or glass. Preferred embodiments are synthetic sheets or synthetic hollow fibers having a thin, high density, nonporous fractional layer of polymer on one or both sides of the support. In the case of a symmetrical or asymmetrical membrane, the preferred embodiment is to minimize the boundary layer on the feed side, but the liquid will contact the membrane on either side.

High density nonporous layers or skins also become an integral component of the membrane and are formed at the same time as the support structure. However, the present invention is not limited to the formation of a high density nonporous layer at the same time as the support structure. The invention will also be carried out by forming a high density, nonporous layer as a component of the membrane (a.k.a.composite part). The high density nonporous layer will be formed at a separate time from the support structure. In this case, the high density nonporous layer then adheres to the support structure.

The support structure is porous or nonporous. High density nonporous skins or support structures are in fact polymeric and inorganic or organic polymers. The polymer may be a linear polymer, a branched polymer, a crosslinked polymer, a cyclized linear polymer, a ladder polymer, a cyclized matrix polymer, a copolymer, a trimer, a graft polymer or a mixture thereof.

Low volatility liquid will wet the support structure. Alternatively, the porous support structure will be treated so that the low volatility liquid does not wet the structure. However, it is not required to carry out the present invention. The present invention will be carried out when the porous support structure is not wetted with a low volatility liquid.

Moreover, the present invention will be carried out when treating the porous support structure so that the structure does not get wet with low volatility liquid. Preferably, the property of the porous support structure is to prevent the low volatility liquid from wetting the structure.

In this situation, if the membrane consists of a dense nonporous layer or skin on only one side, the nonporous layer will result in oil passage as discussed above. If oil is hydraulically permeated through the membrane, the oil will evaporate at a slower rate than water, or not at all, to seal off the membrane and reduce the dehydration rate. Thus, a preferred embodiment is to have a high density nonporous fractionation layer free of defects on one or both sides of the porous support structure. It is necessary to have a high density, nonporous fractionation layer free of defects to prevent oil from penetrating hydraulically through the defects of the fractionation layer. An advantage of having a high density nonporous fractionation layer free of defects on both sides of the porous structure is that the hydraulic transport potential of the oil is further reduced.

In the case of hollow fibers, the feedwater may contact the membrane in or out of the fibers. A preferred embodiment is that externally supplied liquid is supplied at lower operating pressure drops.

The fractionation layer or skin consists of a group of polymers that are chemically compatible with the feed relative to density. The nonporous layer prevents the transfer of significant amounts of oil. The fractionation layer or epidermis is chemically compatible with the oil if it does not chemically react with the oil and physical properties such as size, strength, permeability, and selectivity are not adversely affected by contact with the oil. Dense nonporous layers include polyimides, polysulfones, polycarbonates, polyesters, polyamides, polyureas, poly (ether-) Consists of, but is not limited to, amide ether-amides, amorphous Teflon, polyorganosilanes, alkyl celluloses, and polyolefins. It is.

The fluid is in contact with the membrane in countercurrent, co-current, crossflow or radical crossflow arrangements. Thus either flow is mixed well, not at all, or both flows (ie feed and permeate) are not mixed. The feed flow is preferably well mixed.

The flow of low volatility liquids (eg oils) and water-containing liquids is supplied to the vessel to be in contact with the defect-free, high density, nonporous membrane. However, the process of the present invention is not limited to only supplying liquid to the vessel for contact with the dense, nonporous layer. The invention is also realized by supplying a liquid to the container for contact with the membrane on the non-porous layer or the skin without a high density.

The partial pressure of moisture is reduced by application of vacuum at the permeate side or by the use of a sweep gas having a low moisture vapor pressure, such as carbon dioxide, argon, hydrogen, helium, nitrogen, methane or preferably air. Preferred permeate flows, including the sweep process, are countercurrent, crossflow or radical crossflow modes. The permeation pressure is the same or lower than the supply pressure.

In general, the permeation pressure may be higher than the supply pressure. An example of the case where the permeation pressure is greater than the supply pressure is when the sweep gas is removed from the permeate part. The sweep gas consists of dehydrated compressed air or nitrogen so that the pressure in the permeate is higher than the pressure at the feed side of the vessel. In this scenario, the activity of the high pressure liquid, which is generally removed from the feed, is partially greater on the feed side than on the permeate side.

Membranes based on oil dewatering are good for filtering the incoming liquid. Filtration can be used to remove entrained particulate matter or large volumes of water in the flow. Any technique for filtering liquids known in the art may be suitable. The membrane can prevent breakage of the separation layer by particulate material entrained in the filtration stream.

In a preferred embodiment the membrane consists of hollow fibers with a dense, defect-free, nonporous separating layer on one or both sides of the porous support structure. In a preferred embodiment the boundary layer of the feed is minimized. In addition, the pressure drop across the supply is minimized. Moisture permeate is recovered in the permeate by vacuum or sweep. This moisture is in the vapor or gaseous state. The sweep may be in the form of a gas or a liquid. In addition, the sweep may have lower activity against moisture than low volatility liquids.

The apparatus can be used in applications where vacuum cleaners and other traditional dehydrators have been used. The method and apparatus can be used to process oil in an elongated "kidney-loop" system in which an oil dehydrator is connected to a reservoir that is part of the equipment. The oil is recovered from the process storage tank, processed through the dehydrator and then returned to the storage tank. The oil dehydrator can be operated continuously or intermittently while the main system is running or at rest. The apparatus can also be used to treat fluid in a reservoir off-line. Such a reservoir can be used as a container for controlling a fluid without being connected to driving equipment.

In addition, in traditional applications, the device can be used in-line. Since the space between the feed side and the permeate side is dense and separated by a non-porous barrier, it is possible to operate the equipment so that the feed side and the permeate side are at different pressures. The device can thus be operated under pressure in a system in which oil has been used, with the potential for use as an in-line method and apparatus which is a preferred embodiment of the present invention.

The need for traditional off-line or kidney-loop systems can be reduced and eliminated. The use of recent inventions in in-line and system pressures has made the device compact, lightweight and virtually useful in all hydraulic or lubrication installations. The device can be used in stationary or mobile equipment as no additional power, pumps and adjustments are required.

As far as the drawings are concerned, they will be described as follows. 1 is a detailed plan view of a semi-permeable membrane 18. Membrane 18 comprises a nonporous defect free fraction 22 and support structure 24. The fractionation layer 22 is on either or both sides of the support structure 24.

13-14, the deformation of the semi-permeable membrane 18 consists of a fractionation layer 22 collectively formed together with the support structure 24 by methods known in the membrane art.

In FIG. 2 the two flat plates, semi-permeable membrane 18, are separated due to a number of feed tube spacers 34. Spacers 34 may be made or made of a variety of materials well known in the art, including potting compounds. Each membrane 18 has a skin 22 and a support structure 24. The mixing of feed and permeate flows is such that the permeate aggregate spacer 25, the membrane structure, is located between the membrane 18 and the spacer 34. Membrane 18 is separated by feed tube spacer 34.

Figure 3 shows the embodiment of the co-fiber of the semi-permeable membrane 20. In this configuration, the cofiber membrane 20 comprises the fractionation layer 22 and the support structure 24. The fractionation layer can be present inside or outside the fiber or on both sides.

15-16 are modified views of the cofiber membrane 20. The cofiber membrane 20 is composed collectively by methods known in the membrane art, together with the fractionation layer or skin 22 and support structure 24. As noted above, the fractionation layer or skin 22 may be present on either or both sides of the support structure 24.

FIG. 4A is a mat 20 woven into a plurality of hollow fiber semi-permeable membranes 20. Regarding the weaving technique, the cofiber membrane 20 typically constitutes a weft of mat 30. A number of fillers 28 were used to weave the mat with the cofiber membrane 20. Fillers 28 were used in a typical way to weave mats or nets.

4B is a longitudinal cross-sectional view taken in the direction of the arrow, along line B-B in FIG. 4A. The numbers used in Figure 4B represent the same elements as before. If the fibers were not damaged, some fabric weaving processes could have been used to make the co-fiber mats.

4C shows that mat 30 is helically woven. Generally feed tube spacer 34, such as a potting compound, will be applied directly to the distal end of the mat 30 and will fill the space between the cavity fibers 20. This will be discussed further below.

In FIG. 4D two hollow fiber semi-permeable membranes 20 are helically woven to form rope 32.

5 is a plan view helically woven using a technique that provides a feed space and permeate space in a known helical arrangement and helically woven module of planar sheet semipermeable membrane 18. The feed tube spacer 34 is placed over the fractionation layer 22 before helically squeezing the membrane 18. One or more planar sheet semipermeable membranes 20 may be helically woven simultaneously. In general, multiple planar sheet semipermeable membranes 18 will each be horizontally positioned. Membrane 18 may or may not be separated by spacer 34. Assembly of a plurality of horizontally positioned sheet semipermeable membranes 20 horizontally woven onto the core 60. In general, the spiral should be tightly woven and the feed tube spacer 34 is in contact with the permeation collection spacer 25.

6 is an invention depicted in conjunction with the vacuum transmission mode. Moisture containing feed 40 is transferred to the feed of membrane separation vessel 42 so that the oil is in efficient contact with membrane 18. Feed 40 is optionally heated before contacting membrane 20. Dehydrated low volatility liquid is removed from vessel 42 with effluent 44. Permeation 46 is recovered by vacuum pump 48. Optionally feed 40 flows in parallel or perpendicular to membrane 20 and permeate 46 also flows in parallel or perpendicular to membrane 20 or a combination therefrom. Optionally vessel 42 may be heated.

Clearly, vessel 42 should be sized to suit the desired flow rate of feed 40, the desired operating pressure drop and the amount of water removed. Permeation 46 is evident in the cross flow arrangement, while feed 40 and permeation 46 flow with respect to each other in the reverse flow, in the same direction, and in the radical cross flow.

7 and 8 show the swept gas mode. It is introduced into the permeate side of membrane 20 with respect to the sweep fluid 50. The feed stream is filtered by filter 52 as shown in FIG.

9, 10, 11, and 12 show that the inner diameter fluid of hollow fiber 20 is separated from the outer diameter fluid by potting compound 34. In FIG. 11 oil is discharged by the penetrated core 60. The pierced core 60 is a traditional through core with a housing 62 having a pierced portion 64 and an outlet 68. The penetrated portion includes a plurality of penetrating 66s. Outlet 68 is connected to outlet 44 of vessel 42. The pierced one may have a suitable size and arrangement. The low volatility liquid flows over the housing 62 and the penetration 64. The low volatility liquid enters the housing 62 through the penetrating portion 66. The low volatility liquid is present in core 60 penetrated through outlet 68.

The apparatus and method can be used to dehydrate lubricated oils as well as other fluids such as plant or edible oil, silicone, or other low volatility fluids.

The terms or expressions used in the above specification have been used as terms of the detailed description and are not limited, and are not intended to exclude synonyms of the features or portions described or described.

The scope of the invention is defined and limited only by the following claims.

The present invention provides a membrane-based-method for removing glass, emulsified or dissolved water from oil or low boiling liquids. This method can be used in mobile devices during operation and movement, and can also be used in stationary devices and processes. The operation of this method is simple, but the device in question is small and compact, making it affordable and practical for systems of all sizes.

The present invention also provides a fractionation layer or membrane without defects that does not allow hydraulic permeation of the liquid through the fractionation layer, thereby limiting its transmission through the fractionation layer.

The present invention also provides for the removal of vapor that is permeated through the fractionation bed. Thus, the present invention provides an apparatus and method for more effectively separating glass, emulsified and dissolved water from oil.

In particular, the present invention relates to a method of using a non-porous, defect-free membrane to selectively remove water from oil. More specifically, the method consists in contacting oil to one side ("feed side") of the semipermeable membrane to remove water from the associated oil stream. The membrane divides the separation chamber into a supply side where oil is supplied and a permeate side where water is removed. The permeate side is maintained at a low partial pressure of water through the presence of a vacuum or by using a sweep gas. The water in the oil is in dissolved form or emulsified, dispersed or free form. The membrane material is suitably chemically compatible with the oil, while selectively allowing the transfer of water. This membrane is chemically compatible with oil as long as it does not react with the oil and also does not adversely affect size, strength, permeability and selectivity by contact with the oil.

It is therefore an object of the present invention to overcome the disadvantages of conventional oil dehydration techniques and to provide an apparatus and method for oil dehydration that overcomes these limitations.

Another object of the present invention is to provide an oil dehydrator for removing glass, emulsified or dissolved water from oil.

Another object of the present invention is to provide an oil dehydrator that is easy to operate.

Another object of the present invention is to provide a fairly compact and compact oil dehydrator.

Another object of the present invention is to provide an economic oil dehydrator.

It is yet another object of the present invention to provide an oil dehydrator that can actually be used in small or large systems.

Another object of the present invention is to provide an oil dehydrator that can be used in a moving device while operating and moving.

Other objects and advantages of the invention will be apparent from the following description and the appended claims, in which the accompanying drawings, which form a part hereof, are incorporated by reference, wherein reference numerals refer to corresponding parts in other drawings. .

The membrane-based-method and apparatus for removing glass, emulsified or dissolved water from oil or low boiling liquids according to the invention can be used in mobile devices during operation and movement, and also in stationary devices and processes, Although the operation of the method of the present invention is simple, the device in question is small and compact, so that it can be practically used in a system of any size and inexpensively, and water and water are mixed in a machine, a device, etc. by reliably and simply removing oil, water or moisture. It is a useful invention that can provide oil that is not.

Claims (88)

Next process a) contacting one side of a defect-free, high-density, nonporous membrane with a liquid stream comprising glass, emulsified or dissolved water and oil, wherein the membrane discharges the separation chamber from the feed side to which the liquid stream is supplied and from which the water is discharged. Bar is divided into a transmission surface; 1) A defect-free, high-density, nonporous membrane is a synthetic part of a hollow fiber in which a defect-free, high-density, nonporous fractionation layer is supported on a porous support, 2) the fractionation layer and the porous support are virtually a polymer, b) maintaining a partial pressure differential with respect to water, wherein such water is selectively permeated by "solution diffusion" from the feed side to the permeate side through the polymer fractionation layer as water vapor; c) removing permeated water vapor from the permeate surface by a sweep gas stream or vacuum; d) membrane permeation of oil from the liquid state to the permeate side; e) removing the dehydrated oil from the feed side of the membrane Dehydration method of oil, characterized in that consisting of. Next process a) contacting one side of a defect-free, non-porous, semipermeable membrane with a liquid stream comprising at least water and a low volatility liquid, wherein the membrane contacts the separation chamber with a supply side through which the liquid stream is supplied and a permeate side through which the water is discharged. Separated by; 1) A defect-free, high-density, nonporous membrane is a synthetic part of a hollow fiber in which a defect-free, high-density, nonporous fractionation layer is supported on a porous support, 2) the fractionation layer and the porous support are virtually a polymer, b) maintaining a partial pressure differential with respect to water, wherein such water is permeated from the feed side to the permeate side through the membrane and the low volatility liquid does not permeate to the permeate side by hydraulic transport; c) removing water permeated from the permeate surface; d) removing the dehydrated liquid from the feed side of the membrane Dehydration method of a low volatility liquid, characterized in that consisting of. Next process a) contacting one side of the intact, semipermeable nonporous membrane with a liquid stream comprising at least water and oil; b) the water is dissolved in glass, emulsifying or oil; c) the membrane divides the separation chamber into a feed side through which a liquid stream is supplied and a permeate through which water is discharged; d) maintaining a partial pressure difference with respect to water, such water is permeated from the feed side to the permeate side through the membrane and oil is not permeable to the permeate side by hydraulic transport; e) removing permeated water from the permeate surface; f) removing the dehydrated oil from the feed side of the membrane Dehydration method of oil, characterized in that consisting of. The method for dehydrating a low volatile liquid according to claim 2, wherein the low volatile liquid is an oil. 3. The method for dehydrating a low volatile liquid according to claim 2, wherein the low volatile liquid is a liquid having a normal boiling point that is larger than that of water. 3. The method of claim 2 wherein the water is present in dissolved, dispersed or emulsified form, or in a separated state in the low volatility liquid. 3. The method of claim 2 wherein the defect free, nonporous, semipermeable membrane is comprised of a high density, nonporous, self supporting layer. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous cavity fibers. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet. 4. The method of claim 3 wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as an integral part of the hollow fiber, wherein the high density, nonporous layer is formed simultaneously as a support structure in the hollow fiber. Oil dehydration method. 4. The method of claim 3 wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as an integral part of the flat sheet, wherein the high density, nonporous layer is formed simultaneously as a support structure in the flat sheet. Oil dehydration method. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as a composite part of the hollow fiber, wherein the high density, nonporous layer is formed at a different time than the support structure in the hollow fiber. Oil dehydration method. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as a composite portion of the flat sheet, wherein the high density, nonporous layer is formed at a different time than the support structure in the flat sheet. Oil dewatering method. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the hollow fiber, the hollow fiber having a high density, nonporous layer in one of the pores or outer surfaces. . 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the flat sheet, the flat sheet having a high density, nonporous layer on one surface thereof. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the cavity fibers, the cavity fibers having a high density, nonporous layer in the pores and the outer surface. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the flat sheet, the flat sheet having a high density, nonporous layer on both sides thereof. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of a high density, nonporous layer on a porous or nonporous cavity fiber, and the low volatility liquid is supplied to the side with the high density, nonporous layer. Oil dewatering method. 4. Oil dehydration according to claim 3, wherein the defect-free, nonporous, semipermeable membrane consists of a high density, nonporous layer on a porous or nonporous flat sheet, and the oil is supplied to the side with the high density, nonporous layer. Way. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous hollow fibers, and oil is supplied to the outer surface of the fibers. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous hollow fibers, and oil is supplied to the inner surface of the fibers. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous cavity fibers, and the fibers are spirally wound. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet, the flat sheet spirally wound. 4. The method of claim 3 wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet, and the spacer separates the flat sheet. The method of claim 2 wherein the liquid stream is sufficiently mixed. 3. The method of claim 2 wherein the liquid stream is not sufficiently mixed. 3. The method of claim 2, wherein at least a portion of the total flow of low volatility liquid is aligned in another system which is continuously supplied through the method. 3. The method of claim 2, wherein the method operates as a "kidney loop" in another system in which the fractionation of the entire flow of low volatility liquid is continuously supplied through the method. 3. The method of claim 2, wherein the method operates offline in another system and wherein the low volatility liquid is supplied through the method from a storage device. The method of claim 2 wherein the liquid supply flows parallel to the surface of the semipermeable membrane. The method of claim 2 wherein the liquid supply flows perpendicular to the surface of the semipermeable membrane. 31. The method of claim 30, wherein the flow on the permeate side is parallel to the surface of the semipermeable membrane. 31. The method of claim 30, wherein the flow on the permeate side is perpendicular to the surface of the semipermeable membrane. 32. The method of claim 31 wherein the flow on the permeate side is parallel to the surface of the semipermeable membrane. 32. The method of claim 31 wherein the flow on the permeate side is perpendicular to the surface of the semipermeable membrane. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous hollow fibers, and the feed flows horizontally through the hollow fibers. 4. The oil dehydration of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on the porous or nonporous hollow fiber, and the flow on the permeate side is horizontal to the hollow fiber. Way. 4. Oil dehydration according to claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on porous or nonporous cavity fibers, and the flow on the permeate side is perpendicular to the cavity fibers. Way. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on porous or nonporous hollow fibers, and the feed flows perpendicularly to the hollow fibers. . 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on a porous or nonporous flat sheet and the feed flows horizontally in the flat sheet. . 4. Oil dehydration according to claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on a porous or nonporous flat sheet, and the flow on the permeate surface is horizontal to the flat sheet. Way. 4. The oil dehydration of claim 3, wherein the defect-free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on a porous or nonporous flat sheet, and the flow on the permeate surface is perpendicular to the flat sheet. Way. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane consists of at least one high density, nonporous layer on a porous or nonporous flat sheet and the feed flows perpendicularly to the flat sheet. . 3. The method of claim 2, wherein the flows on the feed and permeate sides are countercurrent. The method of claim 2, wherein the flow on the feed side and the permeate side flows in parallel. 3. The method of claim 2, wherein the flows on the feed and permeate surfaces flow alternately. 3. The method of claim 2, wherein the flows on the feed and permeate surfaces flow radially across. 4. The method of claim 3 wherein the defect free, nonporous, semipermeable membrane comprises a porous support structure, wherein the porous support structure is wetted by a low volatility liquid. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a porous support structure, the porous support structure being treated to be wetted by a low volatility liquid. 4. The method of claim 3 wherein the defect free, nonporous, semipermeable membrane comprises a porous support structure, wherein the porous support structure is not wetted by the low volatility liquid. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a porous support structure, wherein the porous support structure is treated so as not to be wetted by the low volatility liquid. The method of claim 2, wherein the pressure on the permeate side is higher than the pressure on the feed side. 3. The method of claim 2, wherein the pressure on the permeate side is less than or equal to the pressure on the feed side. 3. The method for dehydrating a low volatility liquid according to claim 2, wherein there is a liquid through the sweep gas or the permeate membrane. The method of claim 2, wherein there is a sweep gas through the permeate membrane, the sweep gas is selected from the group consisting of argon, methane, nitrogen, air, carbon dioxide, helium, hydrogen or any mixture thereof Method of dehydration of liquids. 3. The method of claim 2, wherein there is a sweep gas through the permeate membrane, wherein the sweep gas has a lower activity in water than the low volatility liquid. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer, wherein the nonporous layer is substantially polymeric. 4. The method of claim 3, wherein the defect free, nonporous, semipermeable membrane comprises a high density, porous support, the high density, porous support being substantially polymeric. The method of claim 2, wherein the porous support is a ceramic dehydration method, characterized in that the ceramic. The method of claim 2 wherein the porous support is glass. 3. The method of claim 2, wherein the porous support is an inorganic polymer. The method of claim 2, wherein the low volatility liquid is filtered before contacting the semipermeable membrane. 3. The method of claim 2, wherein the semipermeable membrane consists of a plurality of hollow fibers, wherein the hollow fibers are woven into one mat. The method of claim 2 wherein the liquid stream is heated before contacting the membrane. 4. The method of claim 3 wherein the unitary semipermeable membrane consists of a dense, nonporous self-supporting layer having an integrally formed skin. 3. The method of claim 2 wherein the nonporous, semipermeable membrane has a skin integrally formed on at least one side of the support structure. Oil dewatering device, a) fluid storage container; b) a defect-free, nonporous, semipermeable membrane inserted into the vessel which divides the vessel into at least one feed surface space and one permeate space; c) at least one inlet opening in the feed plane space direction; d) at least one outlet opening in the feed plane space direction; And e) at least one outlet opening in the transmissive surface space direction; Oil dewatering device, characterized in that consisting of. 68. The oil dewatering device of claim 67, wherein the fluid storage container is heated. 67. The oil dewatering device of claim 67, further comprising a porous support for supporting the nonporous, semipermeable membrane. 70. The oil dewatering device of claim 69, wherein the nonporous, semipermeable membrane has a skin integrally formed on at least one side of the porous support. 68. The oil dewatering device of claim 67, wherein the nonporous, semipermeable membrane is substantially polymeric. 70. The oil dewatering device of claim 69, wherein said porous support is substantially polymeric. 70. The oil dewatering device of claim 69, wherein the porous support is ceramic. 68. The oil dewatering device according to claim 67, further comprising a sweep gas inlet open in the permeation space direction. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane is comprised of a high density, nonporous, self supporting layer. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous cavity fibers. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet. 68. The method of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as an integral part of the hollow fiber, wherein the high density, nonporous layer is formed simultaneously as a support structure in the hollow fiber. Oil dewatering device. 67. The method of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as an integral part of the flat sheet, wherein the high density, nonporous layer is formed simultaneously as a support structure in the flat sheet. Oil dewatering device. 67. The method of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as a composite portion of the hollow fiber, wherein the high density, nonporous layer is formed at a different time than the support structure in the hollow fiber. Oil dewatering device. 67. The method of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a high density, nonporous layer as a composite portion of the flat sheet, the high density, nonporous layer formed at a different time than the support structure in the flat sheet. Oil dewatering device. 67. The oil dehydration of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the hollow fiber, the hollow fiber having a high density, nonporous layer in at least one of the pores or outer surfaces. Device. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane comprises a support structure in the flat sheet, the flat sheet having a high density, nonporous layer on at least one surface thereof. 67. The method of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of a high density, nonporous layer on a porous or nonporous hollow fiber, wherein the low volatility liquid comprises a high density, non-porous layered one side and a high density, nonporous layer. Oil dewatering device, characterized in that supplied to the side. 68. The oil of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous hollow fibers, and oil is supplied to one of the inner and outer surfaces of the fiber. Dewatering device. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on porous or nonporous hollow fibers, and the fibers are spirally wound. 67. The oil dewatering device of claim 67, wherein the defect-free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet, the flat sheet spirally wound. 68. The oil dewatering device of claim 67, wherein the defect free, nonporous, semipermeable membrane consists of one or more high density, nonporous layers on a porous or nonporous flat sheet, and the spacer separates the flat sheet.