RU1819156C - Device for separating water from the mixture of water and hydrocarbon or water and galogenated hydrocarbon, method for separating water from the liquid mixture of water and carbon of water and galogenated hydrocarbon and a method for dewatering of a wet hydrocarbon gas - Google Patents

Abstract

Use: to separate water from a mixture of water and a hydrocarbon and from a mixture of water and a halogenated hydrocarbon and to dry a moist hydrocarbon gas. SUMMARY OF THE INVENTION: membranes are composed of non-porous, self-sustaining hollow fibers of regenerated copper ammonia cellulose. The membranes absorb water from the stream, which diffuses to the other side of the membrane, from where it is then removed. 3 s.p. f-ly, 7 z.p. f-ly, 6 ill.

Description

The invention relates to techniques for the separation of substances on a semipermeable membrane and can be used in the chemical and gas industries.

The purpose of the invention is to increase the efficiency of separation of water from liquid hydrocarbons or halogenated hydrocarbons, as well as to increase the efficiency of gas dehydration.

In FIG. 1 shows a section (in side view) of a device for draining a gas stream; in FIG. 2 is a partial sectional view of a single fiber used to make a membrane; in FIG. 3 is a partial perspective view illustrating a method of sealing the ends of the fibers constituting the membrane in one embodiment of the device, as a result of which the fibers form a bundle with open ends of the fiber channels to allow the flow of purge (water carrying) air; figure 4 - on an enlarged scale

section of a portion of the membrane; in FIG. 5 is a multi-chamber (multi-stage) drying device in which membranes of the type shown in FIG. 14; Fig. 6 is a schematic illustration of a second embodiment of the present invention.

The device 10 comprises a housing 12, which, in the embodiment of FIG. 1, is elongated and substantially cylindrical. The ends of the housing are provided with covers 14 and 16 having axial holes 18 and 20. Near the ends of the housing 12 are openings 22 and 24 communicating with the internal cavity of the housing 12.

A bundle of hollow hydrophilic fibers 28 extends axially inside the housing 12, forming a membrane 26. The fibers are made from regenerated cellulose, and they preferably have an inner diameter (channel diameter) of about 200

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one hundred

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eating

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μm (10%). By regenerated cellulose is meant, in this case, a copper ammonia regenerated cellulose obtained by a non-chemical process and in a substantially natural state. The copper-ammonia regenerated cellulose is chemically a layer of cellulose molecules. The specific ultrastructure is unknown, but it is known that the layers do not have pores passing through them. Between the layers there is a deuterium bond, creating a highly crystalline structure. The structure is completely hydrophilic and provides the creation of waterways for the diffusion of water and dissolved water-soluble substances. Copper-ammonia regenerated cellulose provides membranes that are significantly thinner than membranes made from cellulosic materials of chemical origin, such as cellulose acetate. The substances diffusing through the membranes of copper ammonia cellulose pass a much smaller distance than the substances passing through the membranes from cellulose acetate. Thus, membranes made of copper ammonia cellulose have a significant positive effect on hydrodynamics due to the presence of a much smaller, but nevertheless more effective barrier, which is overcome only by diffusing water and dissolved water-soluble components.

Unlike cellulose acetate membranes, which are asymmetric microporous membranes, the copper ammonia cellulose membranes of the present invention are non-porous. Unlike known membranes in which ether groups or acetyloxy groups are exposed to the external environment, in the membranes of copper-ammonia cellulose, hydroxyl groups are exposed to the environment, creating a non-destructive chemical layer that is not amenable to dissolution or destruction by the action of hydrocarbons or their halogen - derivatives. In addition, in contrast to the known applications of copper ammonia cellulose membranes for air drying or in dialysis medical equipment, where the membranes were used in the same environment, copper ammonia cellulose, as discovered by this applicant, has an unexpected ability (due to its chemical nature), do not chemically degrade in the presence of hydrocarbons.

This pollution resistance provides the membranes of the present invention with an unexpected ability to continuously separate water from a mixture of water and hydrocarbons or water and halogenated hydrocarbons without pollution.

Methods for making hollow fibers suitable for use in the present invention from copper ammonia cellulose are disclosed in US Pat. No. M: 4,288,494, issued Sept. 8, 1981 to Christopher X. Porter and John A. Taylor, and in the description of US patent No. 4333906. issued June 8, 1982, also on it Porter and Taylor. Other such methods known to those skilled in the art may also be used.

. The spaced walls 30 and 32 are hermetically connected to the inner wall of the housing 12 and actually divide the inner cavity of the housing 12 into end chambers A and C and the central chamber B. The ends of the fibers 28 are sealed into the walls 30 and 32, but, as shown in FIG. 1 ( and shown in more detail in Fig. 3 and 4), the channels 34 of the fibers 28 are left open and communicate with chambers A and C.

Between the membrane 26 and the housing 12, a mesh 36 can be placed, if desired, to provide stability and structural reinforcement to the membrane, but individual fibers are not supported externally.

The device 10 has two separate paths for passing fluids through the housing 12. The fluid supplied to the housing 12 through the opening 22 will flow axially in the housing 12 in contact with the outer surface of the fibers 28 to the opening 24, and the housing 12 forms piping for supplying hydrocarbon fluid from the source and bringing it into contact with the outer surfaces of the membrane along its entire length. The fluid supplied to the orifice 18 will flow through the chamber A, the channels 34 of the fibers 28 and the chamber C, and then exit through the orifice 20 into the storage for the dried hydrocarbon fluid.

Wet gas W (FIG. 2), entering the hole 22, flows, as shown, in the axial direction relative to the fiber 28 (and therefore the housing 12) along the outer wall of the fiber 28, The purge stream of compressed air S, passes through the channel 34 of the fiber 28 in countercurrent with respect to the direction of flow of the wet gas W. In doing so, a positive pressure gradient is maintained through the wall 38 of the fiber 28 from its outer wall 40 to the inner wall 42. In other words, the pressure outside the fiber 28, i.e. inside the chamber B, it is maintained so that it exceeds the pressure in the channel 34, which facilitates the transport of the substance through the wall of the fiber 28 to the channel 34. Despite maintaining a positive pressure gradient (P0 greater than PC), the fibers 28 can be flattened while maintaining the internal pressure Pc at a suitable high level. The pressure gradient can range from a few psi. inch to above 1000 psi inch (70.8 kg / cm) until the fibers are flattened. The higher the pressure, the higher the mass transfer coefficient.

The fibers 28 of the membrane 26 in the device 10 are made hydrophilic, unsupported and selectively permeable to allow diffusion of water and dissolved water-soluble components but not a water-entraining gaseous medium (natural gas, e.g., mainly methane). Due to the lack of support, the fluid stream does not break and continuously flows around the surface of the fibers. This medium flow acts on an increased surface area compared to discontinuous surfaces of known supported membranes, which positively affects the relative hydrodynamics of the system. The water absorbed by the fiber 28 finally diffuses through the wall of the fiber 28 to the inner wall 42. Water molecules, which have appeared on the inner wall 42 of the fiber 28, carry away the purge stream S of air flowing through the channel 34. This stream continuously removes the water protruding on the inner wall 42. Thus, the membrane is a diffusion agent consisting essentially of unsupported non-porous copper ammonia cellulose and having a continuous continuous surface. The purge stream is a water removal means providing a diffusion dynamics such that at least 95% of the water and dissolved water-soluble components are removed from the hydrocarbon fluid in a single passage along the fibers. The purge stream, acting as a water removal means, together with ultra-thin membranes made of copper ammonia cellulose having an unclosed continuous non-porous surface, give significantly improved results in terms of separation dynamics compared to known systems. These factors increase the ability of the device of the present invention to remove water, in

as a result, the device becomes capable of removing at least 9% of water and dissolved water-soluble components from the hydrocarbon fluid in 5 single passes along the fibers.

It is desirable that the fibers in device 10 be as small as possible, because smaller fibers have a higher pressure tolerance and are more resistant to splashing than larger fibers. In addition, finer, and therefore larger, fibers provide a larger surface area for transmission of the medium and, therefore, provide higher productivity.

The four-module device 44-contains separate modules 46-52, assembled according to the principle of counterflow. The wet gas supplied to the device 44 through the wet gas supply port 54 flows sequentially through modules 46-52 and exits as dry gas through the dry gas outlet 56. A purge dry air stream enters a manifold 58 through an inlet 60 for dry air and flows in parallel through channels of respective fibers (not shown) of membranes housed in modules 46-52. A purge stream of dry air flows in parallel through modules 46-52 to a manifold 62, from where moist air is discharged through an opening 64 for discharging moist air.

Suitable membranes for use in the present invention include hydrophilic cellulose membranes of the type of Lieb and Saurirajan membranes described in Volume 2 Synthetic membranes and their use for hyper- and ultrafiltration of materials of the Symposium of the American Chemical Society, Vol. 154 / Ed. Albina F. Turbaka. 1981 Dialysis cellulose membranes can be used. For various applications

5, the permeability of suitable membranes can range from zero to 20 ml of water per hour / mmHg / m.

The second embodiment of the device (Fig. 6) is particularly suitable for industrial applications where water is contaminated with hydrocarbons, fluorinated hydrocarbons or polychlorodiphenyls.

In particular, the device comprises a filtration module 60 made in accordance with the present invention and comprising a plurality of self-supporting hollow fibers of regenerated copper ammonia cellulose. Tank 52 containing a mixture in the form of a contaminated hydrocarbon (such.

like oil) of water, is in fluid communication with the outer surface of the membranes in the housing 60 through a conduit 66. The mixture flowing through the inlet 68 into the housing 60 is under excess pressure created by the pump 70. Water diffusing through the plurality of hollow fibers are collected and drained by gravity from the housing 60 through the outlet 72, 74 into pipelines 76, 78 leading to a collector (not shown). The mixture, which has become concentrated due to the separation of water from it, is discharged from the housing 60 through the outlet 80 and returned via line 82 back to the tank 62. As a result of prolonged recirculation of the mixture, its concentration in the tank 62 increases. From time to time, an additional mixture may be supplied to the tank 62 through a pipe 84. The mixture flow through the pipe 84 to the tank 62 is selectively controlled by a valve 86.

The second embodiment provides a method for separating water from a mixture of water and a hydrocarbon or halogenated hydrocarbon, comprising introducing a water-hydrocarbon mixture and contacting the outer side of the membranes consisting of non-porous, self-supporting hollow fibers of copper-ammonium cellulose having inner and outer surfaces, and absorption of water from a mixture of a membrane and diffusion of water on the opposite side of the membrane. As described above, water is ultimately diverted from the second side of the membranes via lines 76, 78. And the remaining mixture is diverted from the first side of the membranes via line 82 back to tank 62 for recirculation and concentration.

Unlike prior art devices that use cellulose acetate membranes, the apparatus of the present invention can recycle and concentrate hydrocarbon-contaminated water for a long period of time without pollution or degradation. A system using cellulose acetate membranes is unable to effectively separate water from the aqueous hydrocarbon mixture or to withstand sustained recirculation and concentration of the mixture. Acetyl cellulose membranes would have degraded in such a situation and eventually fouled the system. Unlike a dialysis system that uses copper ammonia cellulose membranes, the system of the present invention allows the membrane to be exposed to fluids which, for other membranes, would be corrosive and degraded, but, unexpectedly, the system in in accordance with the present invention is capable of withstanding prolonged exposure to fluids without degradation.

Example 1. In the experimental device 10 with one module of the type shown in figure 1, the membrane 26 contained

0 hollow fiber from regenerated copper ammonia cellulose having a useful surface area of 1 m2. The working volume of the membrane was 125 cm3 (0.125 L). Wet passed through the device

5, methane gas in contact with the outer walls of the fibers constituting the membrane, and at the same time, a dry nitrogen purge flow was directed through the fiber channels.

In one experiment, the temperature of wet methane was 80 ° C (26.67 ° C) with a dew point of 78 ° G (25.56 ° C). The molar methane consumption (calculated as absolutely dry methane) was 4 mol / min, and the water consumption

5 -1.1x10 mol / min. Nitrogen had an inlet temperature of 70 ° G (26.11 ° C) and a dew point of 70 ° G (-56.5 ° C), and the molecular flow rate was 1 mol / min. The methane leaving the device had a temperature of 74 ° G and a point

0 dew 4.5 ° G (although the indicated moisture content was below the lower limit of the measuring range of the instrument). The water flow rate associated with the methane outlet was 6 mol / min. The results indicate, approximately (due to the aforementioned instrument measurement limits), that 94% of the water has been removed from methane. The nitrogen at the outlet had a temperature of 84 ° G. a dew point of 48 ° G and a water flow rate of 2.3x10 mol / min. After 8 hours of work

0 steady state has not yet been reached.

Example 2. In another experiment, in which much higher costs were used (four times higher than in Example 1), a steady state operation was achieved. In this experiment, after 30 hours of operation, the nitrogen dew point at the outlet reached 22 ° G ± 1 ° G and after that remained constant, which indicates the achievement of the established state regime. The outlet dew point was measured at 1.5 ° G, which indicates that more than 95% of the water was removed.

The above example shows that the device 10 in accordance with the present invention is capable of removing more than 95% of the water from the wet methane stream and is supposedly able to remove more than 99% (equivalent to a dew point of about -25 ° G under experimental conditions) of water. Based on these results, it can be assumed that by using the apparatus and method of the present invention, it is finally possible to reach a dew point of 50 ° G or lower.

EXAMPLE 3 Water contaminated with approximately 3% heavy crude oil was passed through a module containing hollow fibers of copper ammonia cellulose with a surface area of 2 m2. Contaminated water passed outside the hollow fibers. Water immediately diffused through the walls of the membrane from hollow fibers and gravity flowed from the inner cavity of the fibers into the collector. The water was distant from the water contaminated with crude oil, it was clear and colorless, while the contaminated water had a dark brown color. Before passing the contaminated water through the hollow fiber membrane, the content of toluene, xylene and ethylbenzene in the contaminated water was determined. Prior to separation, the concentration of toluene was 0.066 (ppm), xylene 0.263 and ethylbenzene 0.062 million, and in pure water, after passing through the membrane, these compounds could not be detected during analysis at a sensitivity limit of 0.005 ml using high performance liquid chromatography methods. A second experiment on the same setup was carried out with a portion of water; intentionally contaminated with 10 tetrachlorethylene. The results were such that it was not possible to detect tetrachlorethylene in water passing through the membrane when analyzed using a highly efficient liquid chromatography technique.

The described examples showed that the present invention can be effectively used to purify water from pollution and return it back to the environment in a safe state, the process of which is highly efficient and effective.

In accordance with the present invention, there is also provided a method for removing water and dissolved water-soluble components from a hydrocarbon fluid. In general, the method comprises the step of passing a stream of hydrocarbon fluid with its direct contact with a continuous unsupported surface (along its length) of a membrane consisting of a plurality of hollow non-porous fibers made of copper ammonia cellulose in one pass. Fibers selectively pass through as a result of diffusion upon contact of the hydrocarbon medium with the fibers, only water and dissolved water-soluble components. Water and

dissolved water-soluble components passing through the membrane are discharged on the other side of the membrane, thereby improving diffusion dynamics and

5 removal of at least 95% water and dissolved water-soluble components from the hydrocarbon fluid. By continuously draining water and dissolved water-soluble components,

0 diffused through the membrane, from the inner cavity of the fibers, support the transmembrane gradient of water and dissolved water-soluble components diffusing through the membrane.

Claims (10)

1. Device for separating water from a mixture of water and a hydrocarbon or halogenated hydrocarbon containing a membrane separator made in the form 0 hollow fibers of cellulosic material, a pipeline for supplying a separable flow to the outer surface of the fibers, a pipeline for draining water penetrating into the fiber channels from the inside of the fibers 5 and a pipe for discharging the cleaned stream, characterized in that. in order to increase the efficiency of the water separation process, the fibers are made of non-porous hydrophilic copper-ammonia 0 regenerated cellulose. 2. The device according to claim 1, characterized in that the fiber material has a water permeability of up to 20 ml of water / h mm. Hg pillar m2. 5 3. The device according to p. 1, characterized in that it is equipped with a storage tank having a pipeline with a control valve for introducing fresh mixture into it and connected to pipelines for 0 supplying a separable flow and discharging the cleaned diaphragm separator stream. 4. A method of separating water from a liquid mixture of water and a hydrocarbon or a halogenated hydrocarbon, comprising passing a mixture flow from the outer surface of the hollow fibers from cellulosic material, separating the water fibers from the hydrocarbon or halogenated hydrocarbon material, and discharging 0 the inner side of the fibers of the water that has penetrated into the fiber channels and the output of a stream purified from water, characterized in that, in order to increase the efficiency of the water separation process, separation 5 by diffusion of water through non-porous hydrophilic regenerated copper ammonia cellulose. 5. A method according to claim 4, characterized in that the water that has penetrated into the channels of the fibers is drained by gravity. 6. The method according to claim 5, with the exception that the recovered stream purified from water is fed to recirculation from the outer surface of the fibers. 7. The method according to claim 6, characterized in that the recycle stream is introduced into the storage tank before being fed to the outer surface of the fibers, where fresh mixture is added. 8. A method of draining a wet hydrocarbon gas, including passing a stream of wet hydrocarbon gas from the outer surface of the hollow fibers from the cellulosic Material, separating the material of the water fibers from the hydrocarbon gas, withdrawing the dried gas, and discharging water in the channels of the water fibers on the inside of the fibers, characterized in that, in order to increase the efficiency of the gas drying process, the wire is separated by absorption and diffusion of water through non-porous hydrophilic copper-ammonia cellulose. 9. The method of claim 8, wherein, in order to improve the removal of water from the inner surface of the fibers, purge gas is passed through the fiber channels. 10. A method according to claim 9, characterized in that the flow of the drained stream and the passage of the purge gas are countercurrent. Fig. 1 with i (-28 GTT-MT / - w RTTl / nf 56 28 Fig. thirty 1819156 -20.12 / 36 (g (g H - sr-r-t ,. V h / h V V /  l О „Ч; y O s 0. x h     I h v t b y (..... d Zc  "H h-1    H - V at V -G - h " 62 Zhe LJ / 64 5, 60 l L 7W  58 FIG. 5 12/3 (g H - sr-r-t / h V  at b §Fe. 1ag If with. in 63 G60