Patent Application
20060231462
1. Technical Field
The present invention relates to a system for improving crude oil and specifically to a method that does not involve the use of traditional distillation. Instead, the crude oil is filtered through a tight filtration media. The pressures and temperatures produced within the media break the longer hydrocarbon chains within the crude oil mixture, producing a more valuable hydrocarbon profile.
2. Description of Related Art
Petroleum is perhaps the most important natural resource. It is produced from underground formations. Sometimes these formations are produced through land based wells while others are produced through offshore platforms. When the petroleum is initially produced, it is often referred to as crude oil, because it contains a mixture of both valuable and less valuable hydrocarbons. Crude oil is refined to break down the less valuable hydrocarbons into a more valuable product, such as gasoline. The refining process adds tremendous value to the produced oil, but is a complicated and expensive process. The cost of a refining plant can easily exceed one billion dollars. Therefore, a need exists for a simpler and less expensive method for achieving many of the same results as traditional petroleum refining.
Petroleum refining has evolved continuously in response to changing consumer demand for better and different products. The original requirement was to produce kerosene as a cheaper and better source of light than whale oil. The development of the internal combustion engine led to the production of gasoline and diesel fuels. The evolution of the airplane created a need first for high-octane aviation gasoline and then for jet fuel, a sophisticated form of the original product, kerosene. Present-day refineries produce a variety of products including many required as feedstock for the petrochemical industry.
Distillation Processes. The first refinery, opened in 1861, produced kerosene by simple atmospheric distillation. Its by-products included tar and naphtha. It was soon discovered that high-quality lubricating oils could be produced by distilling petroleum under vacuum. However, for the next 30 years kerosene was the product consumers wanted. Two significant events changed this situation: (1) invention of the electric light decreased the demand for kerosene, and (2) invention of the internal combustion engine created a demand for diesel fuel and gasoline (naphtha).
Thermal Cracking Processes. With the advent of mass production and World War I, the number of gasoline-powered vehicles increased dramatically and the demand for gasoline grew accordingly. However, distillation processes produced only a certain amount of gasoline from crude oil. In 1913, the thermal cracking process was developed, which subjected heavy fuels to both pressure and intense heat, physically breaking the large molecules into smaller ones to produce additional gasoline and distillate fuels. Visbreaking, another form of thermal cracking, was developed in the late 1930's to produce more desirable and valuable products.
Catalytic Processes. Higher-compression gasoline engines required higher-octane gasoline with better antiknock characteristics. The introduction of catalytic cracking and polymerization processes in the mid- to late 1930's met the demand by providing improved gasoline yields and higher octane numbers.
Alkylation, another catalytic process developed in the early 1940's, produced more high-octane aviation gasoline and petrochemical feedstock for explosives and synthetic rubber. Subsequently, catalytic isomerization was developed to convert hydrocarbons to produce increased quantities of alkylation feedstock. Improved catalysts and process methods such as hydrocracking and reforming were developed throughout the 1960's to increase gasoline yields and improve antiknock characteristics. These catalytic processes also produced hydrocarbon molecules with a double bond (alkenes) and formed the basis of the modern petrochemical industry.
TREATMENT PROCESSES. Throughout the history of refining, various treatment methods have been used to remove nonhydrocarbons, impurities, and other constituents that adversely affect the properties of finished products or reduce the efficiency of the conversion processes. Treating can involve chemical reaction and/or physical separation. Typical examples of treating are chemical sweetening, acid treating, clay contacting, caustic washing, hydrotreating, drying, solvent extraction, and solvent dewaxing. Sweetening compounds and acids desulfurize crude oil before processing and treat products during and after processing.
Crude oils are complex mixtures containing many different hydrocarbon compounds that vary in appearance and composition from one oil field to another. Crude oils range in consistency from water to tar-like solids, and in color from clear to black. An “average” crude oil contains about 84% carbon, 14% hydrogen, 1%-3% sulfur, and less than 1% each of nitrogen, oxygen, metals, and salts. Crude oils are generally classified as paraffinic, naphthenic, or aromatic, based on the predominant proportion of similar hydrocarbon molecules. Mixed-base crudes have varying amounts of each type of hydrocarbon. Refinery crude base stocks usually consist of mixtures of two or more different crude oils.
Relatively simple crude oil assays are used to classify crude oils as paraffinic, naphthenic, aromatic, or mixed. One assay method (United States Bureau of Mines) is based on distillation, and another method (UOP “K” factor) is based on gravity and boiling points. More comprehensive crude assays determine the value of the crude (i.e., its yield and quality of useful products) and processing parameters. Crude oils are usually grouped according to yield structure.
Crude oils are also defined in terms of API (American Petroleum Institute) gravity. The higher the API gravity, the lighter the crude. For example, light crude oils have high API gravities and low specific gravities. Crude oils with low carbon, high hydrogen, and high API gravity are usually rich in paraffins and tend to yield greater proportions of gasoline and light petroleum products; those with high carbon, low hydrogen, and low API gravities are usually rich in aromatics.
Crude oils that contain appreciable quantities of hydrogen sulfide or other reactive sulfur compounds are called “sour.” Those with less sulfur are called “sweet.” Some exceptions to this rule are West Texas crudes, which are always considered “sour” regardless of their H2S content, and Arabian high-sulfur crudes, which are not considered “sour” because their sulfur compounds are not highly reactive.
BASICS OF HYDROCARBON CHEMISTRY. Crude oil is a mixture of hydrocarbon molecules, which are organic compounds of carbon and hydrogen atoms that may include from one to 60 carbon atoms. The properties of hydrocarbons depend on the number and arrangement of the carbon and hydrogen atoms in the molecules. The simplest hydrocarbon molecule is one carbon atom linked with four hydrogen atoms: methane. All other variations of petroleum hydrocarbons evolve from this molecule.
Hydrocarbons containing up to four carbon atoms are usually gases, those with 5 to 19 carbon atoms are usually liquids, and those with 20 or more are solids. The refining process uses chemicals, catalysts, heat, and pressure to separate and combine the basic types of hydrocarbon molecules naturally found in crude oil into groups of similar molecules. The refining process also rearranges their structures and bonding patterns into different hydrocarbon molecules and compounds. Therefore it is the type of hydrocarbon (paraffinic, naphthenic, or aromatic) rather than its specific chemical compounds that is significant in the refining process.
Paraffins. The paraffinic series of hydrocarbon compounds, illustrated in
Aromatics are unsaturated ring-type (cyclic) compounds, such as those shown in
Naphthenes, such as those shown in
Other Hydrocarbons-Alkenes are mono-olefins with the general formula CnH2n and contain only one carbon-carbon double bond in the chain. Alkenes are illustrated in
Dienes and Alkynes. Dienes, also known as diolefins, have two carbon-carbon double bonds. The alkynes, such as acetylene shown in
Nonhydrocarbons. Sulfur Compounds. Sulfur may be present in crude oil as hydrogen sulfide (H2S), as compounds (e.g. mercaptans, sulfides, disulfides, thiophenes, etc.) or as elemental sulfur. Each crude oil has different amounts and types of sulfur compounds, but as a rule the proportion, stability, and complexity of the compounds are greater in heavier crude-oil fractions. Hydrogen sulfide is a primary contributor to corrosion in refinery processing units. Other corrosive substances are elemental sulfur and mercaptans. Moreover, the corrosive sulfur compounds have an obnoxious odor.
Pyrophoric iron sulfide results from the corrosive action of sulfur compounds on the iron and steel used in refinery process equipment, piping, and tanks. The combustion of petroleum products containing sulfur compounds produces undesirables such as sulfuric acid and sulfur dioxide. Catalytic hydrotreating processes such as hydrodesulfurization remove sulfur compounds from refinery product streams. Sweetening processes either remove the obnoxious sulfur compounds or convert them to odorless disulfides, as in the case of mercaptans.
Oxygen Compounds. Oxygen compounds such as phenols, ketones, and carboxylic acids occur in crude oils in varying amounts.
Nitrogen Compounds. Nitrogen is found in lighter fractions of crude oil as basic compounds, and more often in heavier fractions of crude oil as nonbasic compounds that may also include trace metals such as copper, vanadium, and/or nickel. Nitrogen oxides can form in process furnaces. The decomposition of nitrogen compounds in catalytic cracking and hydrocracking processes forms ammonia and cyanides that can cause corrosion.
Trace Metals. Metals, including nickel, iron, and vanadium are often found in crude oils in small quantities and are removed during the refining process. Burning heavy fuel oils in refinery furnaces and boilers can leave deposits of vanadium oxide and nickel oxide in furnace boxes, ducts, and tubes. It is also desirable to remove trace amounts of arsenic, vanadium, and nickel prior to processing as they can poison certain catalysts.
Salts. Crude oils often contain inorganic salts such as sodium chloride, magnesium chloride, and calcium chloride in suspension or dissolved in entrained water (brine). These salts must be removed or neutralized before processing to prevent catalyst poisoning, equipment corrosion, and fouling. Salt corrosion is caused by the hydrolysis of some metal chlorides to hydrogen chloride (HCl) and the subsequent formation of hydrochloric acid when crude is heated. Hydrogen chloride may also combine with ammonia to form ammonium chloride (NH4Cl), which causes fouling and corrosion.
PETROLEUM REFINING OPERATIONS. Traditional petroleum refining begins with the distillation, or fractionation, of crude oils into separate hydrocarbon groups. The resultant products are directly related to the characteristics of the crude processed. Most distillation products are further converted into more usable products by changing the size and structure of the hydrocarbon molecules through cracking, reforming, and other conversion processes. These converted products are then subjected to various treatment and separation processes such as extraction, hydrotreating, and sweetening to remove undesirable constituents and improve product quality. Integrated refineries incorporate fractionation, conversion, treatment, and blending operations and may also include petrochemical processing.
Fractionation (distillation) is the separation of crude oil in atmospheric and vacuum distillation towers into groups of hydrocarbon compounds of differing boiling-point ranges called “fractions” or “cuts.”
Conversion processes change the size and/or structure of hydrocarbon molecules. These processes include: Decomposition (dividing) by thermal and catalytic cracking; Unification (combining) through alkylation and polymerization; and Alteration (rearranging) with isomerization and catalytic reforming.
Treatment processes are intended to prepare hydrocarbon streams for additional processing and to prepare finished products. Treatment may include the removal or separation of aromatics and naphthenes as well as impurities and undesirable contaminants. Treatment may involve chemical or physical separation such as dissolving, absorption, or precipitation using a variety and combination of processes including desalting, drying, hydrodesulfurizing, solvent refining, sweetening, solvent extraction, and solvent dewaxing.
Formulating and Blending is the process of mixing and combining hydrocarbon fractions, additives, and other components to produce finished products with specific performance properties.
Auxiliary operations and facilities include: steam and power generation; process and fire water systems; flares and relief systems; furnaces and heaters; pumps and valves; supply of steam, air, nitrogen, and other plant gases; alarms and sensors; noise and pollution controls; sampling, testing, and inspecting; and laboratory, control room, maintenance, and administrative facilities.
CRUDE OIL DISTILLATION (FRACTIONATION).
Atmospheric Distillation Tower. At the refinery, the desalted crude feedstock is preheated using recovered process heat. The feedstock then flows to a direct-fired crude charge heater where it is fed into the vertical distillation column just above the bottom, at pressures slightly above atmospheric and at temperatures ranging from 650° to 700° F. (heating crude oil above these temperatures may cause undesirable thermal cracking). All but the heaviest fractions flash into vapor. As the hot vapor rises in the tower, its temperature is reduced. Heavy fuel oil or asphalt residue 16 is taken from the bottom. At successively higher points on the tower, the various major products including lubricating oil, heating oil, kerosene, gasoline, and uncondensed gases (which condense at lower temperatures) are drawn off.
The fractionating tower 12, which is typically a steel cylinder about 120 feet high, contains horizontal steel trays for separating and collecting the liquids. At each tray, vapors from below enter perforations and bubble caps. They permit the vapors to bubble through the liquid on the tray, causing some condensation at the temperature of that tray. An overflow pipe drains the condensed liquids from each tray back to the tray below, where the higher temperature causes re-evaporation. The evaporation, condensing, and scrubbing operation is repeated many times until the desired degree of product purity is reached. Then side streams from certain trays are taken off to obtain the desired fractions. Products ranging from uncondensed fixed gases at the top to heavy fuel oils at the bottom can be taken continuously from a fractionating tower 12. Steam is often used in towers to lower the vapor pressure and create a partial vacuum. The distillation process separates the major constituents of crude oil into so-called straight-run products. Sometimes crude oil is “topped” by distilling off only the lighter fractions, leaving a heavy residue that is often distilled further under high vacuum.
Vacuum Distillation Tower. In order to further distill the residuum or topped crude from the atmospheric tower at higher temperatures, reduced pressure is required to prevent thermal cracking. The process takes place in one or more vacuum distillation towers 14. The principles of vacuum distillation resemble those of fractional distillation and, except that larger-diameter columns are used to maintain comparable vapor velocities at the reduced pressures, the equipment is also similar. The internal designs of some vacuum towers are different from atmospheric towers in that random packing and demister pads are used instead of trays. A typical first-phase vacuum tower may produce gas oils, lubricating-oil base stocks, and heavy residual for propane deasphalting. A second-phase tower operating at lower vacuum may distill surplus residuum from the atmospheric tower 12, which is not used for lube-stock processing, and surplus residuum from the first vacuum tower not used for deasphalting. Vacuum towers are typically used to separate catalytic cracking feedstock from surplus residuum.
The cost of building a typical refining plant is staggering and no new refineries have been built in the U.S. since the 1970s. A refinery also tends to be inflexible once designed. The design, for example, is often optimized for a particular feedstock. Moreover, heavy crudes may need to be blended with light crudes or other compounds so that crude can be pumped through a pipeline to a fixed location refinery. In addition, refineries are expensive to operate with all of the energy requirements that the boilers at the various fractionation towers require, catalyst beds that get fouled, heat exchangers that get fouled, etc. These processing units require periodic preventive maintenance activities in order to permit continued operational performance without an unexpected shutdown. Much of the required preventive maintenance cannot be performed during the operation of the various refinery untis, thus the entire refinery must be shut down for a maintenance period every so often. These maintenance periods are known in the industry as turnarounds or shutdowns. These turnarounds can require downtime of 2 to 6 weeks or more and can occur as often as every 18 months. These expensive turnarounds require extensive planning and as well as manpower resources. Further, it should be noted that while the refinery is shut down, it is not producing any income. Therefore, a need exists for a less expensive and flexible system to improve or enhance crude oil. The system must be flexible enough to improve or enhance a variety of crude oil profiles. The system should cost less to build and operate. Further, the system should be transportable to allow its decentralized use. The system should inexpensively permit crudes to be converted to lighter gravity crudes with more commercial value.
The present invention discloses a method and apparatus for enhancing crude oil. Specifically, the present invention includes a pneumatic pressure source which transports crude into a separator. The crude is placed under pressure sufficient to drive the crude into and through the filter media within the separator. As the crude passes through the filtration media, it experiences cavitation effects. The cavitation effects impart mechanical and thermal energy that assists in breaking or cracking the hydrocarbons into more valuable lighter hydrocarbons. The treated crude can then be transported to a collection tank. The particulate matter or build-up material retained on and within the filter media may be removed by the instantenous reverse pressurization of the separator thereby forcing the build-up material away from contact with the filter media and into a concentrator or setting tank, either of which can dewater, dry, and/or further process the build-up material as desired. The present invention thereby addresses the need for a less expensive and more flexible system for enhancing crude oil. In one aspect, the invention transforms crude oil having an API gravity of 26 into crude oil having an API gravity of 35.
The present invention also discloses a novel poppet valve design which insures leak proof function and can be controlled electronically via standard control inputs or pneumatically by the application of positive or negative pressure. The present invention also discloses a novel separator design which utilizes kinetics and cavitation physics to increase filtration efficiency, causing the cracking of hydrocarbons. The above as well as additional features and advantages will become apparent in the following written description.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIGS. 25 to 27 show the use of multiple stages in series, parallel and in combination; and
The use of filtration media to produce improvement in crude oil profiles is both novel and a significant improvement over existing traditional distillation systems. Referring now to
The filtration process begins by drawing the crude oil from the starting tank 401 by means of a first pneumatic pump 410. The pneumatic pump 410 alternately draws the crude oil through two poppet valves 411, 412 via the upward and downward motion of the plunger 413, and alternately pumps the fluid through two out lines 414, 415. As the plunger 413 rises (as show in the present example), fluid is drawn through poppet valve 412. Simultaneously fluid is pumped out through line 414. When the plunger 413 reverses direction and pushes downward, valve 412 closes and the crude oil is drawn through poppet valve 411 and pumped out through line 415.
The crude oil moves through lines 414, 415 to a separator annulus 420. For the purposes of
Once in the fluid ring 422, the crude oil moves in a turbulent manner allowing the desired product to pass through the flux cartridge membrane and into the interior chamber of the flux cartridge 421, leaving behind contaminant particles and larger molecules as residue in the fluid ring 422, on the exterior of flux cartridge 421, and within the fissures of the flux cartridge 421. The pressure supplied by pump 410 pushes the filtered product out of the center of the flux cartridge 421 through a valve 427 and into a second pump, called a pneumatic ejector pump 430. Alternatively, the filtered fluid product may leave the flux cartridge 421 through an ejector bypass valve 428 and travel directly to a product collection tank 402. This ejector bypass is used when a single ejector pump 430 services multiple separator filter pods in alternative embodiments of the present invention.
During the filtration cycle described above, the ejector pump plunger 431 is drawn up (as shown in
The reverse flush operation or ejection cycle begins by stopping first pump 410 and shutting the poppet valves 423, 424 at the top of the separator filter pod in which the annulus 420 is contained. Next, the pneumatic ejector 430 is activated and plunger 431 is driven downward. This motion closes the check valves 432, 433 and stops the flow of filtered fluid past the plunger 431, allowing the plunger to exert pressure on the fluid inside the ejector. The fluid is pushed back through valve 427, through the flux cartridge 421 and into the fluid ring 422. The time period for this reverse ejection flush or ejection cycle is approximately 0.35 seconds and is carried out under higher pressure than the normal filtration cycle driven by pump 410. For example, the pressure exerted on the crude oil by pump 410 may be up to 150 psi (depending on the viscosity of the fluid involved). In contrast, the pressure exerted by the ejector 430 during the reverse flush may be up to 300 psi. This quick, high-pressure reverse burst removes contaminant particles and residue remaining within the fissures of the flux cartridge 421 and those on the outside surface of the flux cartridge 421 and re-homogenizes the particles and residue in the fluid ring 422 back into solution. Poppet valve 426 on the bottom of the annulus 420 is then opened to allow the pressurized contaminant particles and residue solution to flush out of the fluid ring 422 and into a concentrator annulus 440. The concentrator annulus 440, as its name suggests, concentrates the material flushed from the separator 420 by removing a significant portion of the flush fluid used during the ejection cycle. Unlike the separator filter pod, which may contain up to eight annuli in the preferred embodiment, the concentrator 440 contains only one annulus with a flux cartridge 441 seated therein. The flushed contaminant waste enters the concentrator annulus 440 through an open poppet valve 443 and into the interior chamber of the concentrator's flux cartridge 441. The desired effluent fluid passes through the membrane of the flux cartridge 441 and into the fluid ring 442, leaving the concentrated contaminant waste residue in the interior chamber of the flux cartridge 441. Poppet valve 447, which is located at the bottom of the concentrator annulus 440, allows the filtered fluid in the fluid ring 442 to return to the starting tank 401. Poppet valve 443, through which the waste fluid entered the concentrator 440, is closed and poppet valve 444 is opened to let drying air into the interior chamber of the concentrator flux cartridge 441. This drying air provides a mechanism to dewater the concentrated waste and drives additional flush fluid through the flux cartridge 441 membrane and through the return poppet valve 447.
The drying air poppet valve 444 and fluid return poppet valve 447 are then closed, and poppet valve 445, located on the top of the concentrator 440, is opened to allow in pressurized purging air. When the air pressure inside the concentrator 440 reaches a pre-determined or desired level (e.g. 110 psi), poppet valve 446 is opened which allows the waste residue inside the flux cartridge 441 to escape into a waste collection tank 403.
In alternative embodiments, a setting tank may be used in place of the concentrator to permit, for example, crude to be recycled back into the tank 401, or as enhanced product. It has been discovered that some of the material flushed from the separator 120 during the ejection cycle have components lighter than were provided from the initial crude from the crude oil storage tank 401. Without being bound by theory, it is believed that the forces imparted to the molecules within the fissures of the flux cartridge 121 may be responsible for this phenomenon.
Referring to
As the upper pump disc 501 reaches the top of its upward movement, its position is detected by the top magnetic sensor 510. The signal from this sensor 510 is relayed to a central controller, which instructs a control solenoid 520 to reverse the direction of air through hoses 521 and 522. Therefore, pump air will now move through hose 522 into the upper half of the air chamber 505, forcing the upper disc 501 downward, and the exhaust air will flow out through hose 521.
The central controller also instructs a control solenoid (not shown) to open poppet valve 531 and anther solenoid (not shown) to close poppet valve 532. Therefore, as the lower disc 502 moves downward, fluid is drawn into the upper chamber 503 through the upper poppet valve 531. Poppet valve 532, now in the closed position, prevents fluid backflow into the supply line 530 as fluid is pushed out of the lower chamber 504 and through lower outflow line 541. When the upper pump disc 501 reaches the bottom of its movement path, it is detected by lower magnetic sensor 511, which relays the disc's position to the central controller, and the pumping cycle repeats itself as described above. The pneumatic pump 500 as configured in the disclosed embodiment of the present invention is capable of producing flow rates between 40 to 60 gallons per minute. The pneumatic pump and ejector pump are powered by compressed air supplied via air circuit which is supplied by a compressed air source, preferably by a rotary air compressor as is known in the art. The pneumatic pump and pneumatic ejector pump may include carbon coated pump rods and piston components, which provide additional corrosion protection from contact with the untreated influent, effluent and waste materials involved in the process. Most of the other components are preferably constructed of stainless steel. The heads of the poppet valves are preferably made of marine brass because of its malleability, which allows the valves to maintain seal integrity over periods of sustained operation.
The turbulent flow of the crude oil in the fluid ring 602 is represented by curved arrow 610. This turbulent flow is created and controlled by the pressure differential and the rhythmic pumping action of the pneumatic pump (pump 410 in
When fluid flows smoothly without turbulence, this type of fluid flow is called laminar. Typically, when a fluid is flowing this way it flows in straight lines at a constant velocity. If the fluid hits a smooth surface, a circle of laminar flow results until the flow slows and becomes turbulent. At faster velocities, the inertia of the fluid overcomes fluid frictional forces and turbulent flow results producing eddies and whorls (vortices). The present invention utilizes turbulent fluid dynamics to manipulate molecular kinetics such that only the desired, smaller molecules will pass through the membrane matrix 603, shown by arrow 630. In one embodiment, to pass through the fissures of the flux cartridge membrane 603, a molecule in the fluid ring 602 has to enter interstices or fissures at almost a 90° angle or perpendicular to the surface of the membrane 603 when the molecule contacts the membrane as represented by arrow 620. Due to the constant fluid turbulence, only the lighter molecules are able to make this turn fast enough to pass through the membrane 603 and enter the interior chamber of the flux cartridge. Heavier molecules (e.g., longchain and complex hydrocarbons, iron) cannot turn fast enough to reach the appropriate entry vector or angle when they contact the membrane 603. As shown in
The present invention also provides a novel method of achieving the filtration of increasing smaller particle and molecule sizes by membrane emulation, since the filtering effects of a smaller membrane matrix can be achieved without actually changing the porosity of the flux cartridge interstices. Referring back to
Returning to
When the reverse flush cycle is executed, the solenoid 710 directs pump air through the upper hose 711 into the upper half of the air chamber 703, which drives the upper disc 701 downward, forcing exhaust air out of the lower half of the air chamber 704 through the lower hose 712. As the lower disc is pushed down, friction from the seal closes the check valves 731, 732, preventing fluid from passing through. As a result of the closed check valves 731, 732 fluid in the chamber 705 is forced back out through line 721 and back into the flux cartridges positioned within the separator as previously shown herein.
During the reverse flush, the time required for the pneumatic ejector 700 to begin exerting pressure is less than approximately 0.10 seconds and the time required to complete the downward stroke is approximately 0.35 seconds. In one embodiment, the top disc 701 is approximately six inches in diameter and operated to a maximum pressure of 110 psi at normal water. In one embodiment, the lower disc 702 is approximately 4 inches in diameter, producing a maximum operating pressure of 250 psi at normal water. The combination of higher fluid pressure and short stroke time make the reverse flush operation a sudden, shock load to the separator, which aids in the complete and expeditious removal of material residue from the outer surface of each flux cartridge positioned within the separator annuli. In the disclosed embodiment and as an example, the reverse flush operation cycle utilizes between 1200 and 2000 milliliters of rinse fluid to clean one separator pod with eight annuluses therein and the reverse flush cycle is completed within 0.2 to 0.7 seconds depending on the physical characteristics of the fluids being treated such as particle size and viscosity, among others.
The depicted geometric patterns consisting of machined cuts, grooves and holes on and through the transition plates and main body 902-907 are fluid flow channels. These particular geometric patterns are used to ensure even fluid flow to and from the eight annuli in the separator main body 905. The transition plates may be secured to the main body of the separator and/or concentrator with internal threaded fastening means and external threaded bolt means, which provide easy access and removal of the transition plates for facilitating flux cartridge removal and replacement from the annuli of the separator filter pod and concentrator annulus.
Relating
As described above, a concentrator can receive and filter the backwash fluid received from the separator fluid ring during the ejection cycle using the same filtration methodologies discussed herein, except the flow of fluid through the concentrator is in the opposite flow direction in comparison to the separator filter pod. Backwash fluid from the separator filter pod flows into the center into the interior of the concentrator flux cartridge 1920 as indicated by numeral 1940. The desired fluid then filters through the membrane of the flux cartridge 1920 into the fluid ring 1930, similar to the process described above in relation to
After the drying air flow is stopped by closing the appropriate valve(s), a burst of purge air enters the fluid ring 1930 through the port as indicated by numeral 1960. This burst of purge air is similar to the reverse ejection flush used with separator filter pods. Its purpose is to remove reside adhering to the surface and interstices of the flux cartridge 1920, but in this case, the reside must be removed from the inside surface of the flux cartridge 1920 rather than the outer surface which is exposed to the fluid ring 1930. The purge may also be performed with any other preferred fluid in place of air. The contaminant waste removed by the purge is flushed out of the flux cartridge 1920 as indicated by arrow 1970 into a collection tank as previously discussed. In one embodiment, the general external dimensions of the concentrator 1900, including assembled transition plates and valve heads attached, is roughly 40 inches long with a diameter of 7 to 8 inches. As with all exact dimensions and ranges used within this specification, these ranges and numbers are given for purposes of illustration and not limitation.
a is a cross-sectional view of the filter membrane of the flux cartridge inside the annulus of a separator. The filter membrane can be a sintered metal media which is known to exhibit a high porosity and high flow rate and low pressure drop. The arrow illustrates an example of a tortuous path 2102 taken through the filter membrane as a result of the rhythmic pumping action of the pneumatic pump during the filtration cycle in accordance with one embodiment of the present invention.
Seated within each filter pod 2201-2208 is a filter media or flux cartridge 2210.
Without being bound by theory, it is believed that cavitation bubbles having localized areas of very high temperatures and pressures may be created thereby causing several physical and chemical phenomena, including thermal cracking of carbon-carbon bonds as the crude 10 moves through the flux cartridge membrane 2210. Heavy hydrocarbons and residues are thereby cracked into smaller lowering boiling molecules having a higher API gravity. Once the relatively smaller hydrocarbons pass through the flux cartridge membrane into the flux cartridge 2210 interior, the effluent can be routed to a second filter pod 2202. It should also be pointed out that lighter hydrocarbons formed can volatilize and special provisions may be needed to efficiently capture these gases. In one embodiment, an inert gas blanket can be used. Unprocessed crude also tends to have undesirable components such as bottom or base sediment waste (BSW) which can build up along the outer flux cartridge 1210 perimeter in the fluid ring 1220. Such build-up is especially likely to occur at the first filter pod or when there is a step change to a filter pod having a flux cartridge membrane with a smaller micron filter matrix. As a result, the first filter pod to process crude or the first filter pod where there is a step change in the micron size of the filter matrix, may function more as a filter than a cavitation device. Such build-up material can be backflushed by a pressure exerted, for example, by a first pneumatic ejector 2251 through the flux cartridge 2210 and into the fluid ring 2220.
Again, although not explicitly shown in
In the embodiment shown, the pumps and ejectors pneumatically operate at different time intervals that cycle between a filtration cycle (when the pumps P are operating) and an ejection cycle (when the ejectors E are operating). For example, the filtration cycle can occur for a pre-determined amount of time and at the end of this pre-determined amount of time, the Q-pod can be backwashed with a reverse flush from the ejector E. In alternative embodiments, variables other than time and/or in conjunction with time can be used to determine when the cycle interval. One such variable may be an average pressure differential that develops across the flux cartridges 2210 of the Q-pod. The BSW from the first Q-pod 2201 can be then sent to a settling tank where the undesirable solids, such as dirt and sediment, can be removed. The heavier hydrocarbons that failed to pass through the flux cartridge 2210 can then be routed back to the first Q-pod 2201 for re-processing.
The effluent 2211 exiting the flux cartridge 2210 from the first Q-pod is routed to a second Q-pod 2202 during a filtration cycle and enters the second Q-pod 2202 fluid ring 2220. As occurs in the first Q-pod, the crude is forced through the flux cartridge membrane 2210 in a turbulent manner and causes breakdown of the relatively heavier crude into a lighter crude with a higher API gravity. In one embodiment, the filtration cycle causes an average pressure drop across the flux cartridge membrane of between about 30 and 50 PSI and the ejection cycle causes an average pressure drop across the flux cartridge of between about 100 and 300 PSI. Surprisingly, when backpressure is applied during the ejection cycle (e.g., by the first ejector 2251) further cracking of crude occurs and the fluid ring effluent 2221 from the second Q-pod 2202 can have an average molecular weight lower than the effluent 2211 that entered the second Q-pod 2202. Preliminary tests have indicated that additional cracking of the crude can occur during the ejection cycle than in the filtration cycle. This may be due to the vigorous cavitation that occurs in the filter media and its vicinity by rapid changes in directional pressure between the filtration cycle and ejection cycle. Thus, the fluid ring effluent 2221 exiting the second separator annulus is partially enhanced and can be processed further by, for example, being routed back to the first separator annulus 2201 and/or to a concentrator in a manner suggested in the discussion surrounding
In one embodiment, the filter membrane can comprise a catalyst (e.g. cobalt-molybdenum, alumina, aluminosilicate zeolite, palladium, platinum, nickel, rhodium, etc.) to further facilitate hydrocarbon cracking. In one embodiment, a heated or non-heated gaseous stream can be used to facilitate the cracking process. For example, a heated air or oxygen stream can be added or a non-heated hydrogen stream can be added. The examples of heated and non-heated gases are provided for purposes illustration and not limitation.
The instant invention results in numerous advantages. First, it provides an efficient method for enhancing crude oil to ease the load on a refinery. Second, it provides a way to increase the API gravity of crude so that the crude can be handled by refineries that may not be designed to handle heavier crudes. Third, it can help to provide a more stable feed stock to a refinery thereby avoiding upsets that can result in expensive shutdowns, safety hazards, and environmental upsets. Fourth, it can be portable and skid-mounted and can be placed near a well head and enhance crude where needed to facilitate transport, etc. Fifth, it provides for a more economical overall refining operation. Sixth, it provides an economical way to process heavier crude.
While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 60/672,187, which was filed on Apr. 15, 2005, which claims the benefit of and priority to co-pending U.S. patent application Ser. No. 11/042,235 which was filed on Jan. 25, 2005, which claims the benefit of and priority to U.S. patent application Ser. No. 10/820,538, filed on Apr. 8, 2004, which claims the benefit of and priority to U.S. Provisional Application No. 60/540,492, filed Jan. 30, 2004, the disclosures of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60672187 | Apr 2005 | US |
