WO2001037961A2

WO2001037961A2 - Method for continuous processing of fluids using supercritical fluids and microwave energy

Info

Publication number: WO2001037961A2
Application number: PCT/US2000/041930
Authority: WO
Inventors: H. M. Kingston; Abdulhaq Al-Khalidi
Original assignee: Duquesne University Of The Holy Ghost
Priority date: 1999-11-10
Filing date: 2000-11-07
Publication date: 2001-05-31
Also published as: AU4302901A; WO2001037961A3

Abstract

A method for the continuous processing of fluids is based on mixing the fluid with a supercritical fluid and applying microwave energy. The process focuses on the selective solubility of the desired components into supercritical fluid and deemphasizes the influence of the contaminating components of the fluid to be processed. The process of the present invention is particularly advantageous to the recycling of fluids, such as oil, wherein the process is carried out by statically mixing a waste material with a supercritical fluid to dissolve oil from the waste material. Microwave energy is applied prior to, at the same time, or after the static mixing step. Thereafter, undissolved components are allowed to settle and the dissolved oil is separated from the supercritical fluid. Various apparatus for carrying out the method are also disclosed.

Description

METHOD FOR CONTINUOUS PROCESSING OF FLUIDS USING

SUPERCRITICAL FLUTPS AND MICROWAVE ENERGY

BACKGROUND OF THE INVENTION Field of the Present Invention This invention relates to a method for continuously processing fluids (liquids or gas) using supercritical fluids and microwave energy. The method has many applications, but it fundamentally deals with the separation of industrial fluids into sub-components based on the different solubility of the components in supercritical fluids. Microwave energy complements this process in that the microwaves break up emulsion, adsorption and molecular interactions of specific sub-components of the fluids, and it also is used to directly induce energy driven reactions and synthesis and derivitization in an accelerated manner.

Description of the Prior Art

The present invention is particularly useful in the recycling of petroleum products. For example, used lubricating and hydraulic oils are generated by a number of industries, including automotive and commercial shops, large industrial manufacturing facilities, marine facilities and airline and railroad maintenance departments. Used oils are considered hazardous wastes and are heavily regulated. It is the contamination of these oils with water and waste products that prevent their continued use. Generators of used oils are responsible for cradle to grave management of these waste streams and, in most cases, contract with used oil recyclers to remediate or dispose of the waste under the laws that regulate the transport, processing and destruction of the various components that make up these particular waste streams.

Currently, on-site remediation of these waste streams proves to be quite costly. The generators must contract with firms that have special expertise in reclaiming these waste streams as an on-site service.

As an alternative, used oil recyclers can pick up oil from generators for transportation back to a plant for processing. After the oil is processed it can be resold as burning fuel. This process of treating used oils is complex, costly and time consuming and produces waste components that require further remediation. Further, these used oils that are burned as fuel oils result in the original value of the oil being greatly reduced. Through purification to achieve a state as close to original quality and value as possible, much of the value of these recycled materials can be recovered It has been the lack of a puπfication process of sufficient quality that has prevented the direct reuse or higher value use of these mateπals Currently, batch supercπtical fluid systems are commonly employed in separation and puπfication and are fundamentally limited due to the specific technology and design approach. Pπor art exists that employs batch systems for puπfication using supercπtical fluid systems that are at very high pressure, and that employs vessels of large volume; these systems are extremely expensive and less efficient than the present invention. Other pπor art continuous supercπtical fluid systems use a counter flow technology This technology uses a very complex long vertical column where feed mateπal flows from top to bottom and supercπtical carbon dioxide fluid flows from bottom to top, selectively dissolvmg specific components from the feed liquid This particular system is very inefficient and relies on a large surface area on a wire mesh inside the column to stπp off lighter components from the feed liquid. It requires many temperature sensors and complex controls, and it has very limited flow efficiency Consequently, the liquid is usually required to be recycled several times to sufficiently extract desired components

Microwave energy has been used in the pπor art for a number of purposes. For example, Nikola Smardzija, m U S. Pat. No. 4,853,507, descπbes an apparatus for de- emulsification of liquids usmg microwave energy as radiated mto an applicator section consistmg of a wave guide section that has a taper applicator element of low dielectric constant mateπal separating the wave guide section mto a radiation mput void end and a larger volume liquid-filled output end, whereby an emulsion under pressure is put to the wave guide section output end adjacent the applicator element to undergo radiation and convection heating and subsequent separation mto constituent components.

In U.S. Patent No. 4,582,629, Wolf teaches that an oil and water emulsion can be more rapidly separated when exposed to electromagnetic radiation m the range of from 1 to 300 millimeters. The treatment can be in conjunction with other separating and heating devices such as skimmers, gun barrel treaters, heater treaters, and the like. See also U.S. Patent Nos. 5,911,885 entitled Application of Microwave Radiation In A Centrifuge For The Separation Of Emulsion And Dispersions and 5,914,014 entitled Radio Frequency Microwave Energy And Method To Break Oil And Water Emulsions.

Carbon dioxide has been used to facilitate the separation of emulsions For example, in U S Pat. No. 5,435,920 Elfie Penth teaches a process for cleaving spent emulsions such as cooling lubncants by means of carbon dioxide under pressure, and if necessary, heat in an economic and environmentally friendly manner. The emulsion of cooling lubπcant is saturated under pressure with carbon dioxide and is heated and/or cooled until cleavage is achieved. Above the cleavage temperature, a floating water-poor oil phase quickly forms above an oil-poor aqueous phase The effects of supercπtical carbon dioxide have also been studied For example, in Yamaguchi et al , Volumetπc Behavior of Ethyl Esters Related to Fish Oil in the Presence of Supercπtical C0₂, the 4^th International Symposium on Supercπtical Fluids, May 1 1 - 14, Sendai Japan (1997), pp 485 - 488, supercπtical C0₂ was used for the separation and fractionation of certain components of fish oil. The experimental apparatus mcluded a static mixer in a water bath, and was a batch process. Another example of the use of supercπtical C0₂ is Nagase et al., Development of New Process of Puπfication and Concentration of Ethanol Solution using Supercntical Carbon Dioxide, Id at pp 617-619 The experimental apparatus mcluded a pre-heater and a static mixer in an air bath The experimental system was used for solubility studies and not for contmuous processing of fluids.

Notwithstanding advances in the art, the need still exists for a process for treating fluids, particularly the recyclmg of oil, which can be used on-site, which utilizes a contmuous flow system and that proves to be cost effective and environmentally friendly

SUMMARY OF THE INVENTION

This mvention relates to a method for the processmg of fluids - solutions, suspensions, gases, solvated solids and emulsions The process uses a contmuous supercπtical fluid microwave-enhanced procedure. A fluid to be processed is mixed m the same direction with a supercπtical fluid. The process focuses on the selective solubility of the desired components m a supercπtical fluid and de-emphasizes the influence of the contaminating components of the fluid to be processed. The processed components may dissolve selectively m supercπtical fluid according to the pressure and temperature of the supercπtical fluid. Supercπtical fluid can be directly mixed with the sample or sequentially introduced after a heating treatment usmg microwave or thermal energy.

According to one embodiment of the mvention, at the same time the mixture passes through a reactor transparent to microwave energy for contmuous processmg, the umque reactor contains mixing elements for statically mixing the fluids. The processed fluid components may separate into individual components due to microwave energy or undergo chemical reactions enhanced by the microwave energy Microwave energy may be applied initially at low pressure or at high pressure m this process, or it can be substituted with thermal energy, as required.

At least two separation vessels are employed for the contmuous flow and the separation of dissolved and undissolved components from the fluid to be processed m the supercπtical fluid. The supercntical fluid parameters can be contmuously modified to alter the solubility and selectivity of the solvated components. The dissolved components can be phased out according to their solubility in supercπtical fluιd(s), inside separation vessels on a continuous basis, and after depressuπzation at different temperatures and pressures The gas or liquid supercπtical fluid is then recycled on-line, pressuπzed and heated to supercπtical fluid conditions continuously and again used The present mvention is also directed to an apparatus for recycling reusable components from a fluid to be processed compnsmg a reactor compnsmg static mixing elements for mixmg the fluids to be processed and a supercntical fluid, the reactor bemg transparent to microwave energy; a microwave energy source configured to supply microwave energy to the reactor, and at least two separation vessels Additionally, the present invention is directed to an apparatus for recycling reusable components from fluids to be processed compnsmg a microwave energy source configured to supply microwave energy to the fluid to be processed, a reactor compnsmg static mixmg elements for pressurizing and mixing the fluid to be processed and a supercπtical fluid; and at least two separation vessels. Additionally, the present mvention is directed to an apparatus for recycling reusable components from fluids to be processed, compnsmg- a reactor compnsmg static mixmg elements for mixmg the fluids to be processed and a supercπtical fluid, the reactor bemg transparent to thermal energy; a thermal energy source configured to supply thermal energy to the reactor; and at least two separation vessels. One benefit of the present mvention is that it is ideally suited for cleaning up marine oil spills and processmg crude oil sludge Therefore, the present mvention is ideally suited to play a major role m improving the environment.

Another benefit of the present mvention is that it can be used in a number of processes including the puπfication of lubπcatmg oil, gasolme and diesel fuel, used oils, transformer oils and other similar petroleum based samples. Additionally, the present invention can be used m the fractionation of citrus oils mto its components to produce natural sweeteners. The present mvention can be used in the punfication of pharmaceuticals such as copolymers to remove lighter molecular weight components and by-products. The present mvention can also be used m the production of well-defined polymer fractions of very narrow molecular weight ranges, as well as in the fractionation of fats and natural oils in foods and nutπtion.

Another benefit of the present mvention is that it is a continuous process The present invention does not require the use of demulsifier to breakup water-oil complexes. This eliminates a costly and time-consuming step, although demulsifiers can be added to the present invention Because the process is contmuous, it can be automated such that operating labor is dramatically reduced, and the present mvention is less dependent on the education level of the operator requiring less preliminary testmg and judgement. Another benefit of the present invention is the elimination of the need for a large holding tank, previously used in prior art systems for 36 hours/batch. The new process depends on physical constants, that is, solubility parameters of the oil molecules or fluid being treated, not on the contaminants, which are orders of magnitude more soluble and constant compared to the contaminants. These qualities are reflected in the quality control and quality assurance of the final product.

Another benefit of the present invention is that it minimizes waste components that require further remediation. For example, when the present invention is used to process a petroleum product, the amount of water and other residues in the starting material does not alter the quality of the final product or its fundamental process procedure. The present invention minimizes the production of the rag layer, that is, undisolved oil residue and water layer. This reduces or eliminates another cost element, that is, disposing of the rag layer. Another benefit of the present invention when used to process waste oil is that it produces higher quality clean oil than the prior art, which oil can be sold at a much higher value than traditional used oils which are typically sold as #2 burning fuel. The final product of the present invention can be very clear and resembles clean engine oil, rather than the black #2 burning fuel. Therefore, the present invention could play an important role in the future conservation of the hydrocarbon resources. The present invention can also remove chlorinated compounds from the final product. Another benefit of the present invention is that this system can be easily scaled or adapted to both volume and flow. Energy is conserved in the process as part of the fundamental design. Flexibility in integration with other components such as microwave components of the system is enhanced due to this design. The present invention can be scaled down to be dedicated for some specific applications. For example, it can be used on a small scale to recycle well-defined used oil, such as on merchant or navy ships, military engines and other such applications. The clean product can be used as clean engine oil after making up some of the depleted additives.

The present invention is also so compact that it can be used as a mobile processing system making it possible to take the present invention to the source. This is a strategic advantage and one that may introduce a new paradigm in this field. Because of this compact nature it is also possible to integrate the purification into other mechanical systems to continuously purify oil and solvent components.

The fundamental nature of the present invention is more amenable to real time application in conjunction with other processes. The continuous operation and the fewer requirements for a holding tank, allow the process to be applied in other than tank or tanker batches and permit a new flexibility. By adding one module to the existing system it can also be used as a dedicated application for cleaning of oil contaminated solids such as metal parts, machinery or rags with the oil directed to the oil puπfication process

Those and other advantages and benefits of the present mvention will become apparent from the Detailed Descπption of the Preferred Embodiment herein below BRIEF DESCRIPTION OF THE DRAWINGS

For the present invention to be easily understood and readily practiced, the mvention will be descπbed, for purposes of illustration and not limitation, in conjunction with the following figures wherein:

FIGURE 1 is a system used to practice the method of the present invention, FIGURE 2 is a simplified version of the system used to practice the method of the present invention as shown in FIGURE 1 , wherein a high-pressure microwave is used,

FIGURE 3 is a vanation of the system used to practice the method of the present mvention wherem a low pressure microwave is used; and

FIGURE 4 is a vanation of the system used to practice the method of the present mvention wherem thermal heat is used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGURE 1 represents all of the major elements of a system 1 capable of practicing the method of the present mvention. The fluid to be processed is transferred from sample reservoir 2 by sample pumps 4 mto microwave transparent reactor 10. Liquified gas is transferred from solvent reservoir 6 by solvent pump 8 and may be preheated to supercntical conditions by a preheater (not shown). Thereafter, it is mput mto microwave transparent reactor 10. The fluid (liquid, suspension, or gas) to be processed is either mixed directly with the supercπtical fluid upon entering microwave transparent reactor 10, or the fluids to be processed and the supercntical fluid may be sequentially introduced. Because the fluid to be processed and the supercπtical fluid, collectively the flmds, travel together through the system 1 from this point on, the contmuous process is referred to as a co-flow process.

The internal diameter and length of the fluid path within microwave transparent reactor 10 depends on the volume of the fluids per unit time. The fluid path within microwave transparent reactor 10 contains static mixing elements (not shown), which may or may not absorb microwave energy dependmg on the matenal of construction and placement in the system. Microwave energy, from microwave source 11, is absorbed by microwave transparent reactor 10 to provide a constant microwave energy absorber, thereby reducing the influence of the microwave absorbing character of the fluid bemg processed and to provide energy absorption control The static mixmg elements m the fluid path of microwave transparent reactor 10 cause massive turbulence dunng operation to ensure complete mixing of the vaπous fluids mside the reactor and to mass transfer the solubilized components mto supercntical, subcπtical or liquid phase Reactor 10 may take vaπous forms, some of which are discussed in conjunction with FIGURES 2-4 herein below

The supercntical fluid acts as a solvent, which selectively dissolves certain components of the fluid being processed. Table 1 is an example of some of the conventional supercπtical fluids that are commercially available and may be used in the present invention. All conventional solvents can be used as a co-modifier to enhance the solubility parameters of supercntical fluids. Modifiers (usually an organic solvent), usually increase the solvation power of the supercπtical fluids. Modifiers may dissociate sample molecules by forming clusters around them These clusters may dissolve more rapidly in supercntical fluids in companson with sample molecules. Analog modifiers can make supercπtical fluids more selective for certain types of components dependmg on their chemical structure. The analog modifier shares at least a common functional group with the component to be selectively solubilized by the supercπtical fluids. By addmg the modifier directly to the supercπtical fluid, and momtoπng their concentration on lme, or by premixmg modifiers with the fluids to be processed, the selectivity of the supercntical fluid can be "tuned" to the fluid bemg processed.

Table 1 Physical Parameters of Selected Supercritical Fluids

Cntical

TemperCntical Cntical Density Density of

Xe 16.6 58.4 1.10 2.30 3.08 (sat., 111.75 °C)

CC1₂F₂ 111.8 40.7 0.56 1.12 1.53 (sat , -45.6 °C) 1.30 (6.7 atm. 25 °C)

CHFj 25.9 46.9 0.52 — 1.51 (sat., -100 °C)

At least two separation vessels 12, 14 are employed for the contmuous flow and the separation of dissolved and undissolved components from the fluid bemg processed and the supercntical fluid. Additional separation vessels may also be employed for the fractionation of dissolved components usmg isobaπc or isothermal conditions accordmg to their solubilities in the supercπtical fluid at different densities The undissolved components in the supercπtical fluid are allowed to precipitate and settle out in first separation vessel 12 The dissolved components in the supercπtical fluid then enter second separation vessel 14 from the top at a lower pressure and temperature Under the new conditions the supercπtical fluid becomes liquid or gas, as required. The previously dissolved components are no longer soluble and phase separation takes place, which results in the separation of these components to the bottom of second separation vessel 14 The gas may be condensed in condenser 16 and cooled down into liquid, or alternatively the liquid could be cooled. The resultmg liquid is pressuπzed and heated mto supercπtical, subcπtical or liquid before recycling back to solvent pump 8 for contmuous operation. The punfied liquid is drawn off in either first separation vessel 12 or second separation vessel 14 dependmg on its solubility m the supercntical fluid The system 1 of the present invention is usually closed dunng operation but may be open if recycling of the solvatmg fluid is not desired. The separated components of the fluid being processed are removed peπodically from separation vessels 12, 14 by opening valves 13, 15, respectively, at the bottom of each separation vessel 12, 14. The separated components of the processed fluid could alternatively be contmuously drawn off m a controlled manner.

Temperature sensors 17 momtor the temperature of the fluids m reactor 10 That information may be relayed to a central control system 18 which may, m turn, control the microwave source 1 1. Another set of temperature sensors and controls 19 momtor the temperature of the fluids m the separation tanks 12,14. Temperature mformation is relayed to central control system 18 which may then regulate the temperatures m tanks 12,14. Those of ordinary skill m the art will recognize that pressure gauges, valves, and other devices will be needed to properly operate the system 1 shown m FIGURE 1. Such devices are well known in the art and have been omitted from FIGURE 1 for purposes of claπty. FIGURE 2 represents a simplified system used to practice the method of the present mvention, wherem microwave transparent reactor 10 is a high-pressure reactor. Microwave energy is used at the same time as mixmg to energize larger molecular complexes, emulsions, and suspensions separating them mto their individual components. Ultrasomcation device 30 may be installed on microwave transparent reactor 10 to mcrease mixmg efficiency. Ultrasomcation in supercπtical conditions can create sinusoidal compression/decompression waves mside supercπtical reactor 10 to effectively mix the components. In addition as previously descπbed, reactor 10 has static mixmg elements which create massive turbulence. The turbulence increases the efficient absorption of the microwave energy, by preventing shielding of fluid components. In one vanation of the present mvention, the static mixer is also a microwave absorber. This absorbmg mixer makes the microwave absorption characteπstics of the fluid bemg processed much less cntical as the mixer acts as a constant that is more significant than most differences in the absorption characteπstics of vaπous fluid types Also the temperature is more controllable as the static mixer provides a strong constant absorption and passes the thermal energy to the fluid being processed and the supercntical fluid. The heating of the fluids coupled with the rapid mixing of all of the fluids inside reactor 10 will insure maximum solubility and a phase transfer into the supercntical fluid of specific components dependmg on the components' solubility m the supercntical fluid at that pressure and temperature

In FIGURE 2 the supercntical fluid being processed and microwaves are introduced essentially simultaneously and are all present dunng the process as it starts This vanation is important if separation of the components is required as soon as the emulsion is broken up by the microwave energy Because disrupted phases and components are not usually stable in separated form m the ongmal liquid, supercπtical fluid is necessary to solubilize the individual components. The polar components are less soluble m supercπtical fluid while the non-polar components are very soluble in the supercπtical fluid.

FIGURE 3 represents mixing and microwave energy absorption by the fluid being processed at low (or lower) pressure m a similar manner as in FIGURE 2, but with the supercπtical fluid added later. Supercπtical fluid is added at the outlet of microwave transparent reactor 10 and not as the fluid being processed enters microwave transparent reactor 10 This configuration lowers the pressure mside the reactor D The fluid then is pressuπzed and mixed with the supercπtical fluid in secondary reactor 20 which is made of a high-pressure alloy. In reactor 20, solubihzation of selected components takes place accordmg to their solubility in the supercπtical fluid at the pressure and temperature optimized for the specific fluid bemg processed. Secondary reactor 20 may contam similar static mixmg elements as previously descπbed. These elements function m the same manner as descπbed in FIGURES 1 and 2. The process then contmues to the separation tanks as descπbed m FIGURES 1 and 2. The advantage of this vanation is to optimize conditions for microwave energy absorption and supercntical fluid solubility without compromismg either or bemg restncted by mateπal components. These advantages will result m mcreased efficiency of the process and decreased cost of this embodiment of the system.

FIGURE 4 represents another vanation of the present mvention. In this vanation, microwave energy is not needed for certain types of fluid. The microwave energy can be substituted with direct heating of the incommg fluids m secondary reactor 20, that is, a high pressure alloy reactor, to mamtain constant temperature. The advantages of this feature are lower construction costs. While this embodiment is less flexible, it is viable and appropπate for specific applications. The present mvention combmes two fluids (the fluid bemg processed and a supercπtical fluid) at high pressure and achieves mixing by a device employing static mixmg The purpose of this is to vigorously mix two fluids into essentially one homogenous suspension phase This attπbute is deπved from the turbulence and the fluids' high linear flow velocity When the fluids are no longer subjected to the turbulent mixing, the fluids will separate mto individual components according to density and molecular weight and according to their solubility in the supercπtical fluid The insoluble and heavy mateπal will settle out collecting m the bottom of the separation tanks The solution of supercπtical fluid, which includes dissolved components, will flow from the top of the first separation tank to another separation tank One aspect of the present invention is that a seπes of tanks precisely calibrated for temperature and pressure create unique environments and will phase out higher molecular weight components in earlier tanks and progress to lighter components in subsequent tanks without pressuπzmg or expending additional energy

Microwave energy is employed to breakup emulsions by both temperature and disruption of fundamental molecular forces. Temperature is not only necessary in controlling the conditions in the supercπtical fluid section of the system 1 but is necessary m controlling conditions m separation tanks 12,14 and is integrated between both sections of the system 1 Microwave energy is also used to accelerate reactions mcludmg but not limited to chemical and physical reactions. Synthetic combmation, deπvitization and phase separation is enhanced by the addition of microwave energy. Because of the vanable nature of energy adsorption dependent on the polanty and dielectric nature of the sample components of the fluid bemg processed, a static mixer that provides for constant microwave energy absorption is used to place a constant of sufficient mass m the microwave and flow system This is done to reduce the influence of the vanabihty of the microwave energy absorbmg nature of the fluid.

The umon of both components mto a s gle system is done in two different ways, with each havmg umque advantages. First, the mixmg of the supercntical fluid with the fluid bemg processed may be performed as both enter the microwave energy field. Second, the microwave system is used as the initial system with the supercπtical fluid flow bemg performed downstream thereof such that the efficiencies of each system are separate and m a sequential combmation. That also permits a lower pressure microwave cell, increasmg safety and reducing cost considerations. The chemical advantage of each vanation determines the appropnateness of the approach. Certain specific process conditions may require the simultaneous presence of the solvatmg power of the supercπtical fluid. Other applications may reduce cost by using the second approach.

Another embodiment of the present invention includes the addition of an ultrasomcation device Ultrasomcation m supercπtical conditions can create sinusoidal compression/decompression waves inside the supercπtical reactor The advantage of this technology is to increase mixmg strength to a maximum level extending to the molecular level EXPERIMENTAL RESULTS

Table 2

Used oil Starting Oil Co-flow Industrial Parameters Sample; Supercritical Specification Tank 2 Microwave Furnace Fuel Sample Processed Oil

% Water 1.60% 0.30% 0.50%

% Ash 0.85% 0.02% 0.95%

Flash point,F 200 200 >120

Viscosity® 122°F,cSI 43.79 42.1 <50

AP! Gravity,@60°F 27.8 26.1 25.9

Chlorine, in ppm 143.3 0 <0.2%

Sulfur, in ppm 0.456 0.322 <1%

Data and specifications for an example of conventionally cleaned used oil processed using the co-flow supercritical microwave process of the present invention are illustrated in Table 2. Industrial specifications for furnace fuel are also shown for comparison of the final product with these specifications. These results were analyzed by a commercial laboratory and are based on American Petroleum Institute (API) methods. The test setup was as shown in FIGURE 2 and the process parameters were as follows: flow rate of fluid being processed: lg/min, flow rate of supercritical fluid, C0 _: lOg/min, reactor temperature and pressure: 70° C, 500 psi, separation tank no. 1 temperature and pressure: 40° C, 500 psi, and separation tank no. 2 temperature and pressure: 25° C and 1,100 psi.

The present invention may be easily scaled with respect to flow and volume. Small systems 1 may be placed on skids and used in remote locations. For example, a mobile system could be used to service a group of field deployed military vehicles. Small units may also be deployed on ships or other remote locations where the ability to recycle materials is critical. The system can be properly scaled and taken to locations where moderate quantities of materials to be recycled are stored.

The present invention may also be used in processes other than the purification of petroleum based products. The fields of application include many industries such as chemical environmental, food, medical, enzymatic, pharmaceutical and recycling.

The following paragraphs identify applications of the present invention in situations where components have differing solubilities. For example, the present invention can be used to purify azeotrope mixtures into their individual components, e.g. water and ethanol. Water solubility in supercritical fluid C0 is about 0.1%. This is in contrast with very high solubility ot alcohols under the same conditions of temperature and pressure The separation of the alcohol/supercπtical fluid solution from the water is performed easily a cyclone separator which may be used in place of the previously disclosed static mixer A similar system can be used to remove volatile organic compounds from water Supercntical C0 can be mixed with water at vaπous temperatures and pressures up to 1,000 atm to solubi ze organic compounds

There are many examples of the application of the present invention to solubi ty- based puπfication For example, the oil industry, the continuous production of clean and clear oil from used engme oil, a contmuous separation of water and sludge from petroleum products, a continuous fractionation of gasolme/diesel mixture, and a continuous distillation of petroleum raw mateπal into different products are all possible with the present invention The present mvention also finds applications m the recyclmg of cooking oil and the recyclmg of ink. The pressure and temperature for each application is determined by the solubility parameters and phase equi bπum data for each component to be processed m the supercntical fluid. Other examples of applications of the present mvention mclude a contmuous extraction of fat from milk and dairy products, a contmuous extraction of cholesterol from egg yolk, a contmuous extraction of ethanol from fermentation broth, a contmuous extraction and fractionation of butter oil, a contmuous fractionation of glyceπdes, a contmuous separation of enantiomers, a contmuous fractionation of citrus oil and the production of flavmoides. Further examples of applications of the present mvention mclude the contmuous removal of heavy metals from nuclear industry waste. That can be accomplished by adding a detergent, to form micelles around the heavy metal ions. The micelles are then solubilized by the supercntical fluid thereby allowing them to be separated from the wastewater

The following paragraphs identify applications of the present mvention m situations where chemical reactions take place with the supercπtical fluid. An example of this type of application of the present mvention mcludes the treatment of sewage water with increased efficiency through a contmuous supercntical water oxidation process. In this application, water and air can be mixed at a temperature and pressure above cntical parameters of water (cntical temperature 374 ° C and cntical pressure 216 atm). A contmuous process by oxidation destroys organic compounds present at supercπtical conditions and, m certain applications, requires sub-cπtical water to achieve similar results. Use of microwave or thermal energy to increase temperatures above cntical parameters results in a destruction efficiency which exceeds 99 99%. The maximum temperature of the process can be reduced by the introduction of a catalyst such as Mn0₂/Ce0₂. Another example of the application of the present mvention is the continuous supercπtical, or sub-cntical, water oxidation of polychloπnated biphenyls with hydrogen peroxide. In this application, hydrogen peroxide and water are mixed and heated first to above 400° C by microwave or thermal energy to produce hydroxyl radicals (OH) The mixture is then pressuπzed to above 250 atm. The temperature of the high pressure alloy reactor is kept constant with conventional heating to insure 99% decomposition of most types of PCBs. Polymers, like fire retardants, can be oxidized m a similar process The results from the oxidation process are environmentally acceptable substances. This process can also be used at different temperatures and pressures to insure maximum efficiency and oxidation of all types of polychlonnated biphenyls

Other examples of applications of the present invention include a contmuous supercπtical water oxidation of alcohol distillery waste with hydrogen peroxide, a continuous supercntical water oxidation of phenyl, a contmuous enzymatic synthesis of pheny lethyl acetate and carbon dioxide, a contmuous enzymatic esteπfication of alcohols, a continuous enzymatic synthesis of peptides, a continuous emulsion and dispersion polymeπzation of N- vmyl formamide in carbon dioxide, a contmuous deacidification of vegetable oils, a contmuous alkylination of isobutene m supercπtical water, a continuous reaction of alkyl aromatics and supercπtical water, a contmuous hydrolysis of nitnles at sub-cπtical water conditions, a contmuous cellulose decomposition m supercπtical water and a catalyst, a contmuous oxidation of methane mto methanol with supercπtical water, and the contmuous photo-oxygenation of benzene m carbon dioxide.

The present mvention is also applicable to processes based on chemical reactions, solubility and supercπtical fluid anti-solvent recrystallization to produce fine particles and crystals. According to this application of the present mvention, more than one component can be mixed to perform a chemical reaction followed by selective solubi zation of supercπtical fluids followed by fractionation at different supercπtical conditions. The fractionated components can be crystallized online without spendmg additional energy by supercπtical anti-solvent recrystallization. The initial reaction can take place with or without supercπtical conditions. The separation of the reaction components can be based on different solubilities in the supercπtical fluid. The production of the final crystal (powders) of the fractionated and puπfied products is done by sudden depressunzation of the supercntical fluid solution into gas at the bottom outlet of the separation vessel The dissolved mateπal m the supercπtical fluid undergoes nucleation and immediately forms crystals. The size and shape of the crystals can be controlled by the flow rate, the pressure drop rate and temperature. The pressure and temperature for each of the following applications is determined by the solubility parameters and phase equihbnum data for each component to be processed. A known computer simulation based on the modified equation of state (Bmg-Robmson) can be used to predict the design parameters of the system at any scale to insure maximum efficiency of operation.

There are many examples of applications of the present mvention under this category such as a continuous production of polymeπc matenal under supercπtical fluid conditions Other examples of this process include using the monomer as the supercπtical fluid in the production of, for example, polyethylene polymer from ethylene monomer Supercπtical anti-solvent recrystallization can be employed on line to produce fine powder of polymenc mateπal. Other examples of applications of the process mclude a continuous production of fluoroether polyurethanes, a continuous production of impregnated polyurethylene, a contmuous micro-coating of flavon with polymers, a contmuous production of polyurethane aerogels, a contmuous production of powder coatings, a contmuous fractionation of polymer products, and the production of amorphous pharmaceutical particles. Examples of use of the present invention for fractionation of many types of copoiymers mclude using polypropylene- polyethylene copoiymers to remove the low and high molecular weight fractions and the production of medical grade products of very high value on a contmuous manner The process can be used as a recyclmg process for polymenc rags and carpet. In this case the rag matenal is dissolved in solvent, and fractionation and crystallization using the present mvention is performed Other examples of applications of the present mvention includes the contmuous depolymenzation of polymers and a contmuous production of lipid-free human plasma products.

The present mvention mvolves the contmuous fractionation of any mixture of liquids, solutions, suspensions, azeotropes, and fluids mto their individual components. The present mvention is a continuous process where the fluids bemg processed are mixed with supercπtical fluid in the presence of microwave and or ultrasomcation. The process is contmuous and can handle numerous types of flmds to be processed because the process parameters are based on the matenal bemg processed as opposed to the contaminants. The process parameters have much larger values and appear as constants as compared to the contaminants. Thus, the present mvention is less dependent on the analysis of the fluid bemg processed. The microwave energy will enhance the breakup of certam emulsions or speedup chemical reactions. Static mixmg s used to provide massive turbulence, which yields extensive mixmg m a short peπod of time on a contmuous basis enhancing the solvation reactions without the need for massive high pressure batch vessels. The ultrasomcation will speed up solubility of specific components m supercπtical fluids. The dissolved components are earned away from the undissolved components by the supercπtical fluid and can be fractionated into individual components according to their solubility m supercπtical fluid at specific temperature and pressure. The supercπtical fluid is then recycled and used m a close loop system.

The present mvention depends more on the fundamental solubility differences of the remaining valuable key components than on the contaminant wastes that have been introduced and is therefore more fundamental and generally applicable. The water, sludges, residual metal components and other polar components or the waste oils do not determine the process. Rather the inherent solubility of the oil molecules to be recovered determines these conditions making this process more fundamentally robust and generally applicable. While the present invention has been described in conjunction with preferred embodiments thereof, those of ordinary skill in the art will recognize that many modifications and variations may be made. The following claims are intended to cover all such modifications and variations.

Claims

WHAT IS CLAIMED IS:

1. A method of processing a fluid, in which the first two steps may be performed in any order, comprising: mixing a fluid to be processed with a supercritical fluid to dissolve at least one component in the fluid to be processed; applying microwave energy to at least the fluid to be processed; allowing undissolved components to settle; and separating the dissolved component from the supercritical fluid.

2. The method of claim 1 wherein said mixing step includes the step of statically mixing.

3. The method of claim 1 additionally comprising the step of adding sonic energy during said mixing step.

4. The method of claim 1 wherein the supercritical fluid is selected from a group consisting of C0₂, H₂0, N₂0, NH₃, n-C₅, n-C₄, SF₆, Xe, CC1₂F₂ and CHF₃.

5. The method of claim 4 additionally comprising the step of adding a solvent to modify the solubility of the supercritical fluid.

6. The method of claim 1 additionally comprising the step of recycling said supercritical fluid.

7. A method for recycling a reusable oil from a waste material comprising: statically mixing said waste material with a supercritical fluid to dissolve oil from the waste material; applying microwave energy to said mixed fluids; allowing undissolved components to settle; and separating the dissolved oil from the supercritical fluid.

8. The method of claim 7 wherein said steps of statically mixing and applying microwave energy are performed substantially simultaneously.

9. The method of claim 7 additionally comprising the step of adding sonic energy during said statically mixing step.

10. The method of claim 7 wherein the supercritical fluid is selected from a group consisting of C0₂₎ H₂0, N₂0, NH₃, n-C₅, n-C₄, SF₆, Xe, CC1₂F₂ and CHF₃.

11. The method of claim 10 additionally comprising the step of adding a solvent to modifythe solubility of the supercritical fluids.

12. The method of claim 7 wherein said step of allowing includes the step of allowing water and sludge to settle.

13. The method of claim 7 additionally comprising the step of recycling said supercritical fluid.

14. A method for recycling a reusable oil from a waste material comprising: applying microwave energy to said waste material; pressuπzmg said waste mateπal and statically mixing said waste mateπal with a supercπtical fluid to dissolve oil from the waste mateπal, allowing undissolved components to settle; and separating the dissolved oil from the supercπtical fluid.

15. The method of claim 14 additionally compnsmg the step of addmg some energy dunng said pressuπng said waste matenal and statically mixing step

16. The method of claim 14 wherem the supercntical fluid is selected from a group consisting of C0₂, H₂0, N₂0, NH₃, n-Cs, n-C, SF₆, Xe, CC1₂F₂ and CHF₃

17 The method of claim 14 additionally compnsmg the step of addmg a solvent to modify the solubility of the supercntical fluids.

18. The method of claim 14 wherein said step of allowmg mcludes the step of allowmg water and sludge to settle.

19 The method of claim 14 additionally compnsmg the step of recyclmg said supercntical fluid.

20. A method of processmg a fluid, compnsmg: statically mixmg said fluid with a supercπtical fluid to dissolve at least one component m the fluid to be processed; applying thermal energy; allowmg undissolved components to settle; and separating said dissolved component from said supercπtical fluid.

21. The method of claim 20 wherem said steps of statically mixmg and applying thermal energy are performed substantially simultaneously.

22. The method of claim 20 additionally compnsmg the step of addmg some energy dunng said statically mixmg step.

23. The method of claim 20 wherem the supercπtical fluid is selected from a group consistmg of C0_2> H₂0, N₂0, NH_3> n-C₅, n-C₄, SF₆, Xe, CC1₂F₂ and CHF₃.

24. The method of claim 20 additionally compnsmg the step of addmg a solvent to modify the solubility of the supercπtical fluids.

25. The method of claim 20 wherein said step of allowmg mcludes the step of allowmg water and sludge to settle.

26. The method of claim 20 additionally compnsmg the step of recyclmg said supercπtical fluid.

27. An apparatus for processing a fluid, compnsmg: a reactor compnsmg static mixing elements for mixmg said fluid to be processed and a supercπtical fluid, said reactor being transparent to microwave energy; a microwave energy source configured to supply microwave energy to said reactor; and at least two separation vessels.

28. The apparatus of claim 27 additionally comprising an ultrasonication device configured to supply sonic energy to said reactor.

29. The apparatus of claim 27 additionally comprising a recycling system configured to recycle said supercritical fluid from said at least two separation vessels.

30. An apparatus for processing a fluid, comprising: a microwave energy source configured to supply microwave energy to said fluid to be processed; a reactor comprising static mixing elements for pressurizing and mixing said fluid to be processed and a supercritical fluid; and at least two separation vessels.

31. The apparatus of claim 30 additionally comprising an ultrasonication device configured to supply sonic energy to said reactor.

32. The apparatus of claim 30 additionally comprising a recycling system configured to recycle said supercritical fluid from said at least two separation vessels.

33. An apparatus for processing a fluid, comprising: a reactor comprising static mixing elements for mixing said fluid to be processed and a supercritical fluid, said reactor being transparent to thermal energy; a thermal energy source configured to supply thermal energy to said reactor; and at least two separation vessels.

34. The apparatus of claim 33 additionally comprising an ultrasonication device configured to supply sonic energy to said reactor.

35. The apparatus of claim 33 additionally comprising a recycling system configured to recycle said supercritical fluid from said at least two separation vessels.

36. A continuous process for recycling waste oil, the improvement comprising determining the process parameters based on the oil to be recovered instead of the contaminants in the waste oil.

37. A method for continuously processing a fluid, the improvement comprising determining the process parameters based on the solubility of at least one component of the fluid to be processed instead of on the components to be removed from the fluid to be processed.