Sensitive particles from carbon fibres for radio frequency heating
SUBSTANCE: method comprises the following steps: (a) mixing a first substance which includes an oil-bearing rock and a second substance which includes sensitive particles in form of dipole antennae to form a mixture of 10-99 vol. % of the first substance and 1-50 vol. % of the second substance; (b) exposing said mixture to radio frequency energy with frequency or frequencies from said set of one or more radio frequencies and power sufficient for heating the sensitive particles; and (c) continuing exposure to radio frequency energy over a period of time sufficient for heating sensitive particles of said mixture to average temperature higher than about 100°C (212°F). The method is characterised by that said sensitive particles are conducting carbon fibres with length between 1/2, 1/4, 1/8 and 1/16 the wavelength.
EFFECT: said sensitive particles can have advantages for radio frequency heating of hydrocarbon compounds, for example high temperature, anhydrous treatment as well as higher rate or efficiency.
14 cl, 3 ex, 1 dwg
The present invention relates to a method and apparatus for heating materials using RF (radio frequency, RF) energy, which is also called electromagnetic energy. Namely, the present description relates to a method of radio frequency heating of materials with low or zero coefficient of dispersion energy coefficients magnetic loss and electrical conductivity, for example, oil-bearing rocks. For example, the present invention allows for efficient and economical heating of bituminous rocks, oil Sands, oil shale, tar Sands or heavy oil.
Bituminous rock, oil Sands, tar Sands and heavy oil, as a rule, represent a natural mixture of sand or clay and viscous hydrocarbons. Recently, due to the depletion of world oil reserves, high oil prices and demand in it, efforts were focused on the extraction and refining of oil-bearing rocks such types as an alternative source of oil. However, because of the extremely high viscosity of bituminous rocks, oil Sands, oil shale, tar Sands and heavy oil, drilling methods and processing used in the production of conventional crude oil, as a rule, does not apply. Therefore, bituminous rock, oil is Eski, oil shale, tar Sands and heavy oil is usually extracted by the method of open-pit mining, or use the in-situ technology to reduce the viscosity of hydrocarbons, by introducing into the well a couple or solvents, to allow his pumping. However, if any of the mentioned approaches raw materials extracted from the Deposit, may be viscous, solid or semi-solid consistency, respectively, the passage of this material through the pipeline at normal temperatures is difficult, which complicates its delivery to the consumer and increases the cost of processing into gasoline, diesel fuel or other products. Typically, the raw materials are prepared for transportation by adding sand, hot water and caustic cell (NaOH), resulting in a slurry that can be pumped into the extraction unit, where it is stirred and remove the top foam crude bitumen oil. Additionally, typically the raw materials are subjected to annealing for allocation from oil Sands, oil shale, tar Sands or heavy oil more viscous bitumen crude oil for distillation, splitting or processing of crude oil into usable petroleum products.
Traditional methods of heating bituminous rocks, oil Sands, oil shale, tar Sands sludge is heavy oil have numerous disadvantages. For example, standard methods typically require large amounts of water and energy. In addition, when using traditional methods it is very difficult to obtain rapid and uniform heating, which complicates the processing of bituminous rocks, oil Sands, oil shale, tar Sands or heavy oil. Preferably, both environmental and economic/technological reasons, to reduce (or eliminate completely) the amount of water used in the processing of bituminous rocks, oil Sands, oil shale, tar Sands or heavy oil, this requires efficient and environmentally friendly way of heating, suitable for processing bituminous rocks, oil Sands, oil shale, tar Sands or heavy oil after extraction from the soil.
One possible alternative is the way of radio frequency heating. The term "radio frequency" is understood in this document widely and includes any part of the electromagnetic spectrum with wavelengths shorter than visible light. Wikipedia gives the definition of "radio frequency" as the range from 3 Hz to 300 Hz, and defines the following frequency sub-bands:
|Extremely low frequency||ELF, ELF||3-30 Hz||10000-100000 km|
|Very low frequency||SLF, subwoofer||30-300 Hz||1000-10000 km|
|Low frequency||ULF, ULF||300 to 3000 Hz||100-1000 km|
|Very low frequency||VLF, VLF||3-30 kHz||10-100 km|
|Low frequency||LF, LF||30-300 kHz||1-10 km|
|The average frequency||MF, MF||300 to 3000 kHz||100-1000 m|
|High frequency||HF, HF||3-30 MHz||10-100 m|
|Very high frequency||VHF, VHF||30-300 MHz||1-10 m|
|Ultra-high frequency||UHF, UHF||30-3000 MHz||10-100 cm|
|Ultra high frequency||SHF, SHF||3-30 GHz||1-10 cm|
|Extremely high frequency||EHF, EHF||30-300 GHz||1-10 mm|
"Radio-frequency heating" is defined herein in a broad sense as to heat the material, substance or mixture under the influence of RF energy. Microwave ovens are well-known special case of the radio-frequency heating. Radio frequency heating may have advantages consisting in speed, deep heat or adjustable depth heating, or even selective heating, in which one of the components of the mixture is heated more than the other. For example, RF energy can penetrate into the fibers of the wood for drying the inner adhesive joints without the risk of burning. In some processes of refining hydrocarbon compounds to relatively cold oil-bearing rock add boiling water, the temperature of the resulting mixture/solution may be insufficient. As to raise the temperature above the boiling point at atmospheric d is no economically feasible, apply the methods of radio-frequency heating, which increases the temperature of the solution without the use of steam or vessels high blood pressure.
The nature and applicability of radio frequency heating depends on several factors. In General, most materials perceive electromagnetic waves, however, the degree of heating under the influence of RF energy may be completely different. Radio frequency heating depends on the frequency of electromagnetic energy, power and electromagnetic energy, distance to the source of electromagnetic energy, the conductivity of the heated material, and also on whether the heated material is magnetic or nonmagnetic. In fact hydrocarbon molecules practically does not conduct electric current, have a low coefficient of dielectric loss and practical zero magnetic moment. Therefore, directly hydrocarbon molecules are bad receptors radio frequency heating, for example, they can only slowly be heated under the influence of RF fields. For example, kerosene coefficient D scattering can set at 0.0001, and for distilled water of) 0.157 at a frequency of 3 GHz, i.e. the radio-frequency field can heat the water in 1570 faster than oil.
Similarly, a mixture of water and hydrocarbons can not resist the power of the now heated to the necessary extent. Water, even distilled, can absorb radio-frequency heating. However, the use of water during radio frequency heating is limited to a temperature of 100°C (212°F) at atmospheric pressure as the water in the vapor phase badly perceives radio frequency oscillations. In addition, in some areas, water resources may be insufficient, and the use of water in the processing of oil-bearing rocks may be limited or even impractical.
One aspect of the present invention is a method and apparatus for radio frequency heating of materials with low or zero coefficient of dielectric loss, magnetic loss factor and electrical conductivity. For example, the present invention can be used for radio frequency heating of oil-bearing rocks, such as bituminous rock, tar Sands, oil shale, tar Sands or heavy oil. The present invention particularly suitable for RF heating of oil-bearing rocks above 100°C. when at atmospheric pressure the water can remain in a liquid state. One example of the implementation of this method comprises first mixing approximately 10%-99% by volume of a substance, for example, oil-bearing rocks, with 1%-50% by volume of the substance, which contains a miniature dipole are receivable the particles. This mixture is then subjected to RF exposure method, causing heating of the mentioned mini-dipole receptive particles. RF exposure may be attached in a period of time sufficient to heat the aforementioned mini-dipole receptive particles surrounding substance by means of heat exchange, so that the average temperature of the mixture above 100°C (212°F). After reaching the required temperature of the mixture, RF exposure can be terminated, with virtually all of these mini-dipole receptive particles can optionally be removed, resulting in a gain of a heated substance, practically free from the aforementioned mini-dipole receptive particles used in the process of radio frequency heating.
Other aspects of the present invention will be described in further description.
Figure 1 shows the block diagram of algorithm and equipment for radio frequency heating of oil-bearing rocks using mini-dipole receptive particles.
Figure 2 illustrates a mini-dipoles and associated structures receptive particles (shown not to scale) in the oil-bearing rock and a corresponding radio-frequency equipment.
Hereinafter the present invention will be described in more detail, it will be demonstrated the Ana one or more embodiments of the present invention. However, the present invention can be implemented in many different forms and ways of its implementation given in this description should not be considered as limiting the invention. These implementation options are examples of the present invention, the scope of which is defined by the claims.
In one of the embodiments of the present invention, a method of heating the oil-bearing rocks, for example, bituminous rocks, oil Sands, oil shale, tar Sands or heavy oil using RF energy.
Described in this document may be used either for heating oil bearing rock that is extracted from the soil, prior to distillation, splitting or separation processing, or it can be used as an integral part of the distillation process, splitting or separation processing. Oil-bearing rock may include, for example, bituminous rock, tar Sands, oil shale, tar Sands or heavy oil, which is extracted through open pit mining or drilling. If mined oil-bearing rock is solid or contains solid particles larger than 1 cubic centimeter, oil-bearing rock in front of the radio frequency heating can be Rastro the Lena or premalatha and converted into the mixture, powder or brought to a fine state. Oil-bearing rock may include water, however, an alternative, it contains less than 10%, less than 5%, or less than 1% by volume of water. Preferably, the oil-bearing rock water is not added, as in the present invention proposed means of radio frequency heating in the complete absence of water. The present description, in particular, is suitable for RF heating of hydrocarbon compounds without water emulsions, as well as for radio-frequency heating above 100°C, when the water in the liquid phase, as emulsified perceiving substance outside of the tank high pressure can not attend.
Oil-bearing rock, which is used in the present method, is generally non-magnetic or nitromannite, as well as non-conductive or maloprodaja. Therefore, the oil-bearing rock itself is in General not suitable for RF heating. For example, dry, i.e. not containing water, oil-bearing rock may have a coefficient of dielectric loss (ε") is less than 0.01, 0,001, or 0,0001 at 3000 MHz. Such oil-bearing rock may have a negligibly small magnetic loss factor (µ)and the conductivity, which is less than 0.01, 0,0001 0,001 or Cm/m at 20°C. Described in this document the methods, however, are not limited to hydrocarbon products is Tami from any specific magnetic or conductive properties, and can be used for radio frequency heating of substances with higher coefficients of dielectric loss (ε"), magnetic loss (µ) or electrical conductivity. Described in this document the methods are also not limited to oil-bearing rock, and is widely applicable for radio frequency heating of any substance with a coefficient of dielectric loss (ε") is less than about 0.05, 0.01, or 0.001 at 3000 MHz. They are also applicable for radio frequency heating of any substance having a negligibly small magnetic loss factor (µ"), or the electrical conductivity of less than 0.01 Cm/m, 1×10-4Cm/m or 1×10-6Cm/m at 20°C.
Receptive particles in the form of miniature dipoles
In this way to provide improved radio frequency heating in conjunction with the oil-bearing rock is used perceiving patterns in the form of mini-dipole antennas. "Perceiving" herein is any substance that absorbs electromagnetic energy and converts it into heat. "Mini-dipole" herein referred to as any receptive particles, responsive to radio frequency energy is similar to dipole antennas, and most are less than 10 cm, 5 cm, 1 cm or 0.5 cm
Perceiving substances have been proposed for applications such as food packaging for m is kravanosau furnace, thin films, thermosetting adhesives, polymers with radiofrequency energy absorption and heat-shrink tubing. Examples of the receiving material is described in U.S. patent No. 5378879, 6649888, 6045648, 6348679 and 4892782, which are incorporated herein by reference.
In this way as receptive particles in the oil-bearing rock may be spread thin threadlike conductive structures such as metal wire or carbon fiber. The mentioned thread form mini-dipole antennas, which serve to capture and scattering in the form of heat radiofrequency energy/electromagnetic fields. The method of heating may be resistive due to the movement of electrons or charge carriers to overcome the resistance in the above-mentioned dipole structure, for example, electric current 1 and heating in accordance with the first law Joule, or Q=I2Rt.
In the General case, the antenna may include conductive structures that are used to convert electrical current into electromagnetic waves and Vice versa. Canonical antennas are linear or circular, depending on the type - dipole or framework, as well as rotor and divergence of the flux of the electric field. The area of the simplest antennas include the area near zone, the Central zone and the far zone radiation. Field types, environment is x antenna, include both the electric field (E)and magnetic field (H). If the antenna is made of conductive material, it may leak electric currents, i.e. the antenna may also act as an electrode. Radiofrequency applicator device for supplying radio-frequency fields) can interchangeably be called dipole antenna (for example, a slot antenna or electrode pair.
Half-wave dipole antenna includes a thin linear conductor, the length equal to approximately half the wavelength (I=λ/2). The effective aperture or effective area loaded, the resistor coordinated small dipole antennas may be equal to Aem=3λ2/16π=0,06 λ2here , if the dipole antenna includes a thin conductor, the effective area can thousandfold to surpass physical area. Thus, one dipole antenna of the thin conductor is capable of converting radio frequency energy from a very large surrounding area, compared to its physical area. For example, if you use shavings of metal foil as a cloud dipole anti-radar reflectors reflecting area significantly exceeds the total physical area of the individual dipoles. An example of the use of the aperture cloud of dipoles is the orbital dipole belt, SF is marovany around the Earth in the framework of the project West Ford (Measured Physical Characteristics Of The West Ford Belt ("Measurement of the physical characteristics of the zone West of the Ford") F.. Heart et al.), Proceedings of the IEEE, Vol.52, Issue 5, May 1964, pages 519-533). Project West Ford, tenuous cloud of dipoles (dipole wire diameter 0,0018 see, for example, AWG 53, and a length of 1.78 cm) to the earth's orbit was used as a passive repeater for communication (at a frequency of about 8 GHz) between ground stations. This dipole formation, possibly resembled a ring around the Earth, similar to the rings of Saturn, however, the dipole education was optically transparent. Even a small amount of thin dipoles in radio frequency applications, it may produce a significant effect.
Next, the mini-dipole threads can be executed with the resonant length equal to, for example, a ½ wavelength. In other cases, mini-dipole may have a small electrical length that is less than the resonant length, to increase the depth of penetration of the RF field. For example, the length of the mini-dipole can be equal to ¼ wavelength, 1/8 wavelength or 1/16 wavelength. In the case of a resonant half-wave dipole resistance of conductive fibers may preferably be about 73 Ohms to provide a resistive load formed by them dipoles, for example, the resistance Rrradiation is approximately equal to the resistance Rllosses in the conductor of the dipole. Alternatively, the resistance of the conductive fibers may be equal to from 50 Ohms to 73 Ohms or 73 Ohms to 100 Ohms.
Who is step RF energy can be implemented on a single frequency or in a specific range of radio frequencies for different modes of heating. For example, when using both low and high frequencies can be achieved as deep heat, and increased surface heating. Surface heat can lead to hardening of the surface, the effect of drying, the change in the external appearance and the like. Mini-dipole receptive particles 210 have increased susceptibility to the electromagnetic field, i.e. provide an increased RF heating at frequencies corresponding to the harmonics, especially the odd harmonics (e.g., F, 3F, 5F), where F is the main resonant frequency). For mini-dipole receptive particles characterized by an increase in temperature gradient with increasing frequency. Bandwidth 3 dB (50% change heating) thin half-wave dipole at resonance is approximately at the main resonance frequency may be about 13 percent for small diameters, such as d<λ/50.
Radio-frequency heating using mini-dipoles can be carried out, for example, with the use of receptive particles of carbon fibers, flakes, carbon fibers or fabrics made from carbon fiber (for example, pieces of carbon cloth). Carbon fiber or flakes, carbon fibers can be less than 5 cm in length and less than 0.5 mm in diameter. Preferably, carbon fiber or carbon flakes in the hair are less than 1 cm long or less than 0.1 mm in diameter. The dipoles of carbon fibers or pieces of carbon fabric can, for example, be less than 5 cm×5 cm×0.5 mm, or alternatively, less than 1 cm×1 cm×0.5 mm Mini-dipole receptive fibers do not have to be straight, no matter whether they relate to each other.
Suitable carbon fibers, for example, the modern generation of structural graphite fibers, preferably, provide active electrical resistance, i.e. the losses in the conductor. Graphite fibers are inexpensive and can be relatively inert chemically. Such fibers may be about 0.02 mm 0,010 mm, 0.005 mm or 0,001 mm in diameter, and may include atoms of carbon, United in microscopic crystals that are oriented almost parallel along the fiber. A commercial sample of graphite fiber is chopped graphite fiber brand HexTow 1900/IM, manufactured by Hexcell Corporation, Stamford, Connecticut. This product comes in the form of rectangular plates, which are in the processing of break them up into pieces with the liberation of the individual fibers, which is a way of introducing a dipole of carbon fiber in the oil-bearing rock.
Suitable square receptive particles of carbon fibers can be treated as a dipole type antennas and the antennas of the framework type. If the perimeter of square b is ISOC to ½ wavelength, this resistive square close to the panel the form of a coil antenna, and the flux of the electric field is converted into an electrical current flowing along the perimeter of the square, i.e. the electromagnetic coils. Despite the fact that the beam half-wave coil antenna in the form of a perimeter of the square is not Omni-directional, such antenna may have shallow minima pattern, this square obviously has a larger physical area than the thin filament dipole and may be preferred for applications that require a higher degree of heat.
Mixing the oil-bearing rocks and receptive particles
Preferably, performing the step of mixing or distribution, in which the composition comprising the receiving dipoles, mix or distribute in oil-bearing rock. The mixing step can be performed after the above-mentioned crushing, grinding or grinding oil bearing rock, or simultaneously with the crushing, grinding or pulverizing process oil bearing rock. The mixing step may be performed using any suitable method or device, providing a practically uniform distribution of the receiving dipoles. For example, there may be used a sand mill, cement mixer, mixer continuous soil on istia or similar equipment. Perceiving the dipoles can also be mixed with, or in addition to mixed during transport by pipeline.
The advantage of the described herein methods is that a large amount of receptive particles can optionally be used without adverse effect on the chemical or physical properties of the processed oil bearing rock. Consequently, the composition comprising receptive particles may, for example, be mixed with the oil-bearing rock in the amount of from about 1% to about 50% by volume of the total mixture. Alternatively, the composition comprising receptive particles is from about 1% to about 25% by volume of the total mixture, or from about 1% to about 10% by volume of the total mixture.
Receptive particles can uniformly be distributed in a heated substance, if necessary uniform heating. Alternatively, receptive particles may be distributed unevenly, if you want to uneven heating. For example, the effective electromagnetic square half-wave resistive antenna in the air at a frequency of 2450 MHz is 0,119λ2/2=3,6 square centimeters (1.4 square inches), which may correspond to the length of the dipole in 6.1 cm (2.4 inches). The degree of exposure (density receptive particles) in this example may be about 0.5 receptive particles n is a cubic centimeter (1 or receptive particle per cubic inch) of the heated substance. In other substances, as well as in the case of resonance, the length of the receiving dipole can be I=(λ/2)(1/√µr/εr). Depending on the substance or frequency, the average concentration of the receiving particles may be from 0.1 receptive particles per cubic centimeter to about 10 receptive particles per cubic centimeter, or 1 receptive particles per cubic centimeter to about 5 receptive particles per cubic centimeter. However, if the receptive particles are closer to each other than λ/2 TT, there is a significant interaction in the near zone between the dipoles, thus further increasing the concentration receptive particles is undesirable.
An example of a mini-dipole receptive particles is more preferable compared to conventional carbon perceives of substance, as the radiofrequency heating is provided mainly not using dielectric heating, or heating by means of the magnetic moment due to atomic or molecular properties of carbon, and due to the properties of electrical conductivity of carbon fibers, flakes, carbon fibers or carbon fabric, as well as their shapes corresponding to the antenna structure, for example, inside the heated medium is formed of a dipole antenna or dipole antenna the grid.
Radio frequency heating
After mixing, comprising a receptive particles, and oil-bearing rocks, the mixture can be heated using radio frequency energy. Resistive heat receptive particles, causes heating of the entire mixture by conduction. The preferred frequency of the radio-frequency radiation, its capacity and the distance to the source can be different in different embodiments of the invention and depend on the properties of oil-bearing rocks, selected receptive particles, and the desired mode of radio frequency heating.
In one of the embodiments of the present invention, radio frequency energy can be applied in such a way as to cause heating of the receptive particles by radiation of the near zone, for example by induction. Induction heating involves the effects of radiofrequency fields on electrically conductive materials with the creation of electric current. When the conductive material is in an alternating magnetic field resulting from relative displacement of the field source and conductor or due to changes in the magnetic field in time, there is a vortex flow. This may cause the circulation of a current or closed, the flow of electrons in a conductor. Circulation currents form electromagnets, m is gnite fields which oppose the magnetic field changes in accordance with Lenz's law. These vortical flows causing heating. The intensity of the heat, in turn, depends on the intensity of the RF field, the conductivity of the heated material and the rate of change of the electromagnetic field. There may be a correlation between the frequency of the RF field and the depth to which it penetrates into the substance; in General, higher frequency gives a greater degree of heat.
RF source used for radio frequency induction heating can represent, for example, a coil antenna or a magnetic applicator near zone. RF source typically includes an electromagnet, through which pass the high-frequency alternating current. For example, the RF source may include a heating induction coil, a chamber or a container with a coil antenna or a magnetic applicator near zone. Example frequency RF for radio frequency induction heating may be from about 50 Hz to about 3 GHz. Alternatively, the frequency of the RF radiation can be from about 10 kHz to about 10 MHz, 10 MHz to about 100 MHz or 100 MHz to about 2.5 GHz. The power of the radio frequency energy emitted by the RF source may be, for example, from about 100 kW to about 2.5 MW, alternatively, from about 500 kW to about MW, or, alternatively, from about 1 MW to 2.5 MW. It is preferable to provide the correct temperature load mini-dipole receptive particles, as even one thin thread can convert large amounts of energy.
In another embodiment of the present invention the source of RF energy can provide radio frequency energy in the far zone, selected receptive particles act as miniature dipole antenna that generates heat. One of the properties of the dipole antenna - conversion of radio frequency waves into electric current. Accordingly, the material of the dipole antenna may be selected so as to provide resistive heating under the action of electric current. Instead of RF energy near-field or induction field on the heated mixture can be affected by radio frequency energy in the far zone, i.e. the radio wave. Used frequency radio frequency radiation in this example may, for example, to coincide with the resonance frequency of the dipoles of carbon fiber. The depth of heating can also be adjusted, if the frequency or the size of the dipoles to choose far from resonance. The power of the radio frequency energy emitted by the applicator can be adjusted in a wide range, since the dipole receptive particles to depict ablaut a passive linear device. The impact of radio frequency heating may be, for example, 100 watts per cubic foot (0.03 m3or about 10 kW per cubic foot (0.03 m3). As a description of the existing level of technology in this document by reference includes the article "The RF Charactristics Of Thin Dipoles" ("RF characteristics of thin dipoles") C.L.Mack and .Reiffen, IEEE proceedings, Vol.52, issue 5, May 1964, pages 533-542.
In any of those described herein of embodiments of the invention, radio frequency energy can be influenced in a period of time sufficient to heat the surrounding oil-bearing fluid, rock or sand heated perceiving mini-dipoles. For example, the exposure to RF energy may continue for a period of time sufficient for the average temperature of the mixture exceeded approximately 70°C (150°F). Alternatively, the RF energy can affect the mixture up until the average temperature of the mixture reaches, for example, the boiling point of water, for example, 100°C (212°F) or 90°C (200°F)150°C (300°F) or 200°C (400°F). Alternatively, the RF energy may affect up until the average temperature of the mixture will not be sufficient for distillation or pyrolysis in accordance with the molecular weight of the hydrocarbon. Possible temperatures in excess of 540°C (1000°F), depending on the mother of the La fibers dipoles for example, can be obtained temperature greater than typically required in the processing of hydrocarbons. In one modification of the embodiment of the invention, the exposure to RF energy may be part of the process of distillation or cracking, the mixture can be heated to a temperature above the pyrolysis temperature of hydrocarbons to break down complex molecules, for example, kerogen or heavy hydrocarbons into simpler molecules (e.g. light hydrocarbons). Currently, it seems that for herein of embodiments of the present invention, a sufficient interval of time preferably ranges from about 15 seconds, 30 seconds or 1 minute to about 10 minutes, 30 minutes or 1 hour. After the mixture of hydrocarbons and receptive particle reaches the desired average temperature, exposure to radio frequencies may be terminated. For example, the RF source may be turned off or suspended, or the mixture can be removed from the RF source.
Remove and reuse receptive particles In some embodiments of the invention refers also to the ability to remove receptive particles after the mixture of hydrocarbons and receptive particles have reached the required average t is mperature.
If receptive particles left in the mixture, in some embodiments of the invention it may be desirable to modify the chemical and physical properties of the original substances. For example, it may be desirable that the mixture contained a significant amount of powdered metals or metal oxides, polymer dipoles or fibers. One alternative is the use of receptive particles with a low volume fraction, if they do use. For example, in U.S. patent No. 5378879 described the use of permanent receptive particles in the final products, such as heat shrink tubing and thermosetting adhesives and gels, while stating that in the General case, it is preferable to avoid particles in the products of more than 15%, and indeed, in the context of this patent, such products can be performed only with relatively lower ratios. The present invention offers an alternative, which consists in removing receptive particles after radiofrequency heating. The ability to remove receptive particles after radiofrequency heating in the present description allows you to reduce or eliminate undesirable changes in the chemical or physical properties of the oil bearing rock, preserving the possibility of using large volume fractions used perceiving particles. Stood the, including receptive particles may therefore function as a temporary heating of the substance, and not as a permanent Supplement.
Method of removing composition containing receptive particles may vary depending on the type receptive particles and the density, viscosity or average size of the particles in the mixture. If necessary or desired, the removal of the receptive particles can be performed together with the additional step of mixing. If you use a magnetic or conductive receptive particles, almost all receptive particles can be removed using one or more magnets, for example, permanent magnets or electromagnets. Carbon fiber, carbon fiber cereal or a fabric of carbon fiber can be removed by flotation, centrifugation or filtration. For example, removing receptive particles can be carried out either directly during RF heating a mixture of oil-bearing rocks and receptive particles, or upon completion of the radio-frequency heating, after a time sufficient for the temperature of the oil bearing rock fell not more than 30%, or, alternatively, not more than 10%. For example, usually the temperature of the oil-bearing rocks during the removal of the receptive particle support is t equal to not less than 93°C (200°F), alternatively, the average temperature exceeds 200°C (400°F).
Another advantage of the described in this document example embodiment of the invention can be the fact that receptive particles after removal from the heated mixture can be reused.
Alternatively, in some cases it may be more convenient to leave a certain proportion of receptive particles (or all receptive particles) in some or all of the mixture after it is processed. For example, if the receptive particles are pure carbon, which is harmless and inexpensive, it may be preferable to leave the receptive particles in the mixture after heating to avoid the cost of their removal. In another example, the oil-bearing rock was put into her receptive substance can be subjected to pyrolysis to highlight useful lighter hydrocarbon fractions, and the bottom residue after pyrolysis may contain a perceiving substance and used in further or disposed of as waste, without removing the receptive substance.
Refer to figure 1, there is shown a block diagram of the algorithm for one of the embodiments of the present invention. In this variant embodiment of the invention included the container 1, which contains the first substance with a coefficient dielektricheskii the loss of e less 0.05 at 3000 MHz. The first substance, for example, may include oil-bearing rock, for example, bituminous rock, tar Sands, oil shale, tar Sands or heavy oil. The container 2 contains a second substance, including mini-dipole receptive particles. Mini-dipole receptive particles can include any described herein mini-dipoles, for example, carbon fibers, flakes, carbon fibers or carbon cloth. The mixer 3 is designed for distribution of the second substance, including receptive particles in the ground substance. The mixer 3 may include a mixer of any type suitable for mixing various substances, soil, or oil bearing rock, for example, concrete mixer, mixer soil and the like. The mixer can be separate from the container 1 and container 2, or the mixer may be an integral part of the container 1 and container 2. The heating tank 4 is designed to hold a mixture of the first substance and the second substance during heating. The heating capacity can also be separate from the mixer 3, the container 1 and container 2, or it may be part of one of these components (or all components). Also available antenna 5, capable of emitting electromagnetic energy in accordance with the description of this document for heating the KJV is anotai mixture. The antenna 5 can be a separate component located over, under, or near a heating capacity of 4, or it may be part of the heating tank 4. Optionally, there is an additional component filter 6 to separate almost all of the second substance, including mini-dipoles from the first substance. Waste 7 can be removed or recycled after filtration and heated hydrocarbon product 8 store or transport.
With reference to figure 2 describes a device for radio frequency heating of oil-bearing rocks. Mini-dipoles 210 is distributed in the oil-bearing rock 220. Mini-dipoles, preferably, is formed partially conductive carbon fibers. Fragments 212 tissue may contain carbon fiber mini-dipole 210, fragments of fabric bloom with the release of the mini-dipoles of carbon fiber. In another example, the segments 212 tissue can remain intact, forming a receptive 214 particles in the form of a miniature framework antennas. The preferred carbon fiber in practice can include many different geometric shapes, while retaining susceptibility to radio-frequency radiation, the functionality of the antennas and the ability to heat transfer oil-bearing rock 220. Oil-bearing rock 220 may contain any concentration of hydrocarbon molecules, which themselves are not awlays the appropriate receptive substance for RF heating. The antenna 230 is placed in sufficient proximity to the mixture receptive particles 210 and oil bearing rock 220 to provide heat, which may be due to the near area far area or both simultaneously. The antenna 230 may be a dipole "butterfly", however, the present invention is not limited to this example, and can be used, depending on the particular application, the antenna of any kind. Used capacity 240 may be made in the form of tanks, separator cone or even pipeline. Can be applied to any method of mixing, such as a pump (not shown in the drawing). In some applications, the container 240 may be missing, for example, by heating the dry rocks on the conveyor. Can also be used a standard radio frequency screen 250. The transmitting equipment 260 generates a time-varying (for example, radio frequency (RF) current trace to the antenna 230. The transmitting equipment 260 may include various functionality of the radio-frequency transmitting equipment, such as equipment matching impedance (not shown in the drawing), the different RF communication circuits (not shown in the drawing) and a control system (not shown in the drawing).
Thus, an improved radio frequency heating of oil-bearing rocks and hydrocarbons provide by introducing n the x conductive structures, such as fine carbon fiber or squares with sufficient electrical resistance. Mentioned conductive structures can have properties of antennas and to respond to electromagnetic fields and radio waves by the emergence of electric current and the associated heat. A relatively small number mentioned conductive structures may be sufficient, since the effective aperture of a thin antenna can be many times greater than its physical area.
The following examples illustrate some embodiments of the present invention. Examples are as small-scale laboratory tests. However, experts in this field of technology can obviously based on the previous detailed description to apply the described embodiments on an industrial scale.
Example 1: radio frequency heating of oil-bearing rocks without perceiving particles
Sample - ¼ Cup oil Sands of Athabasca district (Athabasca) was taken with an average temperature of 22°C (72°F). The sample was placed in a glass Pyrex container. For sample heating was used GE microwave DE68-0307A with a capacity of 1 kW at a frequency of 2450 MHz for 30 seconds (100% power this microwave oven). The resulting average temperature after heating was 51°C (125 Tons).
Example 2: radio frequency heating of oil-bearing rocks using receptive particles of carbon fiber
Sample - ¼ Cup oil Sands of Athabasca district (Athabasca) was taken with an average temperature of 22°C (72°F). The sample was placed in a glass Pyrex container. The said oil-bearing sand was added 1 tablespoon of cereal carbon fiber (chopped carbon fiber brand HexTow 1900/IM, produced Hexcell Corporation, Stamford, Connecticut) with an average temperature of 22°C (72°F) and stirred until a homogeneous mixture. For sample heating was used GE microwave DE68-0307A with a frequency of 2450 MHz for 30 seconds. The resulting average temperature after heating amounted to 115°C (240°F).
Example 3: radio frequency heating using square receptive particles of carbon fiber
Sample - ¼ Cup oil Sands of Athabasca district (Athabasca) was taken with an average temperature of 22°C (72°F). The sample was placed in a glass Pyrex container. The said oil-bearing sand was added 1 tablespoon of squares of carbon fibers with an average temperature of 22°C (72°F) and stirred until a homogeneous mixture. For sample heating was used GE microwave DE68-0307A with a capacity of 1 kW at a frequency of 2450 MHz. The resulting average temperature after heating amounted to 82°C (180°F).
1. The method of radio frequency heating of oil-bearing rocks using a set of one or more radio frequencies, comprising the following steps:
(a) mixing a first substance, including oil-bearing rock, and second substances, including receptive particles in the form of a dipole antenna, with the formation of a mixture of 10%-99% by volume of the first substance and 1%-50% by volume of a second substance;
(b) the impact on the above-mentioned mixture of radio waves with a frequency or frequencies of the mentioned set of one or more of the radio frequency and power sufficient to heat receptive particles; and
(c) continued exposure to radio frequency energy for a time sufficient to heat the receptive particles mentioned mixture to an average temperature in excess of approximately 100°C (212°F),
characterized in that the said receptive particles are conductive carbon fibers in the form of filaments with a length that is selected between 1/2, 1/4, 1/8 and 1/16 of the wavelength.
2. The method according to claim 1, wherein the first substance is an oil-bearing rock with a coefficient of dielectric loss (ε) less than 0.05 at 3000 MHz.
3. The method according to claim 1 or 2, characterized in that the resistance of the conductive fibers is from 50 to 100 Ohms.
4. The method according to claim 1 or 2, further comprising the subsequent destruction of providing Utah receptive particles of the above-mentioned mixture.
5. The method according to claim 1 or 2, characterized in that the said oil-bearing rock includes bituminous rock, tar Sands, oil shale, tar Sands or heavy oil.
6. The method according to claim 1 or 2, characterized in that the average size of the receptive particles less than 1 cubic centimeter and preferably less than 1 cubic millimeter.
7. The method according to claim 1 or 2, characterized in that the radio frequency is in the range from 10 kHz to 10 MHz or 100 MHz to 3 GHz.
8. The method according to claim 1 or 2, characterized in that the said mixture comprises 70%-90% by weight of the first substance and 30%-10% by weight of the receptive particles.
9. The method according to claim 1 or 2, characterized in that the said mixture comprises a slurry or viscous liquid.
10. The method according to claim 4, characterized in that the removal of the receptive particles is carried out in a time when the mixture is still subjected to RF heating.
11. The method according to claim 4, characterized in that the removal of the receptive particles carried out upon completion of the radio-frequency heating after a time sufficient for the temperature of the oil bearing rock fell not more than 30%.
12. The method according to claim 11, characterized in that the removal of the receptive particles is carried out in a time when the temperature of the oil bearing rock is more than 93°C.
13. The method according to claim 11, characterized in that the removal of FOTS is inmusic particles is carried out in a time when the temperature of the oil bearing rock is more than 200°C.
14. The method according to claim 4, further comprising reusing the receptive particles after removal from the heated mixture.
SUBSTANCE: conversion device for induction heating based on a parallel bridge resonant inverter comprises two valve bridges on four controlled valves with DC and AC diagonals, parts of a throttle of an oscillating circuit, a source of supply, two capacitors, a double-winding inductor, semi-windings of which are arranged on a side surface of a crucible along the axis of the inductor and perpendicularly to this axis in an alternating sequence. In a control system in process of charge melting high-frequency single-phase electromagnetic field is generated, and in process of electromagnetic mixing and heating of a melted metal, double-frequency double-phase electromagnetic field is generated: low-frequency electromagnetic field with high-frequency modulation. By low frequency the electromagnetic field generated by the second valve bridge is shifted by 90° el. relative to the first valve bridge.
EFFECT: generation of a high-frequency single-phase electromagnetic field at the stage of metal melting and double-frequency double-phase electromagnetic field at the stage of electromagnetic mixing of melted metal and its heating with one conversion device, simplification and reduction of losses.
2 cl, 2 dwg
SUBSTANCE: induction hot air furnace is made in form of "Ш"-shape magnetic conductor and has horizontal closed channel for metal melting in form of torus of elliptic cross section. Primary winding is made on a middle core of the "Ш"-shape magnetic conductor; the secondary winding consists of two parts positioned over the first winding so, that its one part is over a horizontal channel with melt of metal, while another one is under the channel.
EFFECT: raised efficiency of melt mixing in furnace and its raised output due to elimination of oxides build-up in channel part.
SUBSTANCE: plant of induction heating of pipelines comprises a device of conversion and control, a heat exchanger, besides, the conversion and control device is arranged on the basis of an autonomous current inverter with quasiresonant switching, the load of which is an inducting wire, representing a multiple-core copper conductor in heat-resistant insulation, arranged on surface of the heat exchanger along its whole length in a single turn, and the heat exchanger represents a system of pipelines, inside which plates of magnetic materials are radially arranged along whole length.
EFFECT: invention makes it possible to increase efficiency factor of heating system heat transfer, to increase controllability of heat transfer processes, to increase capacity and area of thermal field exposure.
SUBSTANCE: device for pipeline induction heating comprises conversion and control device, heating element, conversion and control device is arranged on the basis of autonomous current inverter with quasi-resonant switching, and heating element is a conductor with multiwire current-conducting strand of high conductivity in heat-resistant insulation, arranged along pipeline axis, or at the angle to this axis, one turn forming a circuit or parallel connected turns of several circuits to form temperature field. Temperature field may be controlled due to displacement of conductor of one circuit along pipeline section, if straight direction conductor relative to reverse one is located at the maximum distance equal to diametre of pipe, heat transfer will be maximum, along full section of pipeline, as direct and reverse wires approach each other in pipeline section, temperature field exposure is reduced.
EFFECT: expansion of functional capabilities for creation of a thermal field of heating system, improved repairability, higher control over heat release processes, reduced weight and dimensions.
2 cl, 8 dwg
SUBSTANCE: invention refers to machine-building industry and can be used for heating of parts with hole (ring type) with currents of commercial frequency to temperatures allowing to restore metal-ceramic layer of discs of friction couplings by sintering. Device for induction heating of parts at application of metal-ceramic layer by sintering consists of special transformer with primary winding; heated metal part with a hole through which magnetic conductor of transformer passes is used as secondary short-circuit winding; at that, magnetic conductor of transformer and primary winding consists of not less than three sections. Each section is connected to separate phase of three-phase electric AC mains of commercial frequency; automatic control for maintaining temperature mode is installed in one of the sections, and heated part is installed into the box with heat protection and fixed with holding-down device.
EFFECT: use of this device allows saving the consumed energy, excluding skewing of power circuit phases and adapting parametres of the device to the process heating mode of parts during sintering.
2 cl, 1 dwg
SUBSTANCE: device comprises closed magnetic conductor covered with induction primary winding and secondary short-circuited winding, which is formed by combination of electrically and mechanically connected elements with the help of fixing device in the form of hollow pipe. Between external surface of active part of fixing device and internal circuit of secondary winding there are rings installed and made of the same material as the elements of secondary winding, and process holes are arranged in them, through which heated medium circulates relative to internal surface of secondary winding.
EFFECT: increased active area of thermal surface of secondary winding.
SUBSTANCE: vortex induction heater comprises magnetic conductor reservoir of cylindrical shape with input nozzle of liquid or gas coolant supply and output nozzle for drain of this coolant, and induction winding of copper wire enclosed into sealed toroid cylindrical vessel of insulating material. At the same time inside specified reservoir there are metal pipes attached as concentrically arranged relative to each other with identical gap to form labyrinth-like passage for specified coolant in direction from inlet nozzle to outlet nozzle, and induction winding is arranged inside specified pipes. The second version of heater provides for fixation of reservoir on frame, to which ribbed pipe of coil type is fixed, one end of which is connected to inlet nozzle of reservoir, and its other end is connected to output nozzle of this reservoir, or pipes ribbed with plates and connected parallel to each other and to inlet and outlet nozzles.
EFFECT: improved operational characteristics.
2 cl, 2 dwg
FIELD: machine building.
SUBSTANCE: induction heater of bushing surface consists of first inductor made in form of cylinder coil out of cooled current conducting tube connected to high frequency current source and inserted inside aperture of bushing with gap and of second inductor identical to first one. Also turns of coils of the first and the second inductors alternate forming periodic sequence. Ends of coils are joined with a jumper, while starts are connected to the source of high frequency current Distance between surfaces of neighbour turns of coils is not less, than one third of the gap between heated surface of the bushing and surface of a coil turn.
EFFECT: expanded efficiency of inductor for through heating for heating surface of small diametre apertures.
2 cl, 1 dwg.
FIELD: electrical engineering.
SUBSTANCE: proposed heater comprises three-phase transformer with ferromagnetic core. Transformer primary is connected to AC circuit and its secondary that makes heat exchanger for fluid medium. Aforesaid heat exchanger consists of three chambers, each representing different-diametre cylinder arranged concentrically one into the other and plugged on top and bottom with the help of face plus to form tight hollow chamber for fluid medium to be heated therein and to house cores with primary. Pipeline feeding fluid medium into aforesaid chambers is arranged at heater bottom. Two branch pipes to feed fluid medium into first and second chambers are connected to pipeline parallel to each other. End of pipeline feeding fluid medium is connected directly to third chamber. Fluid medium outlet pipeline is arranged on heater top. End of pipeline discharging fluid medium is connected to either first or third chambers. Two other branch pipes to discharge fluid medium are connected to pipeline parallel to each other. Fluid medium branch pipes and pipeline can be arranged at cylinder chamber bottom.
EFFECT: higher efficiency.
8 cl, 3 dwg
FIELD: electrical engineering.
SUBSTANCE: proposed AC induction heater comprises main inductor connected to power supply, additional inductor placed in main inductor magnetic field to generate current resonance in additional inductor circuit.
EFFECT: higher efficiency.
SUBSTANCE: liquid heating apparatus comprises a heat generator comprising a housing having a cylindrical portion and a liquid movement accelerator, designed as a cyclone, a pump connected to the heat source via an injection nozzle, where at least one insert is placed, and a heat exchange system. The insert is formed as a continuous plate along the injection nozzle oriented perpendicular to the ends of the cyclone. The insert in the injection nozzle forcibly expands the jet in its entry into the cyclone, which results in formation of a vacuum region, downstream the compression region, the vacuum again, compression, etc. As we move into the cyclone, collapse and cavitation are formed in turns on each element of the jet flow in these regions, providing hot water or other process fluid.
EFFECT: invention makes it possible to improve heating efficiency and reliability of a fluid device.
10 cl, 5 dwg
FIELD: engines and pumps.
SUBSTANCE: electrically driven pump-heat generator comprises encased scroll, impeller, discharge outlet, stator and drive motor hollow rotor running in plain bearings. Heat tube is made inside said hollow rotor. Hydrodynamic rotary cavitator fitted on the shaft incorporates ultrasound resonance cavitation amplifier. Coaxial heat tubes are fitted on hollow shaft between said stator and rotor.
EFFECT: higher efficiency, decreased electric power consumption.
2 cl, 1 dwg
SUBSTANCE: hydraulic heat generator comprises a cylindrical body with a cover and a bottom, an element in the form of a wound spring, nozzles for supply of cold water and drain of hot water. A wound flat spring with holes is fixed to turns of a hollow element, in its cylindrical part, outside, in the horizontal position, and on the vertical pipe installed inside the element there are hollow washers installed, filled with a heat-accumulating substance and equipped with holes. The vertical shaft from a wind engine via a reducer and a horizontal shaft having a solid disc at the end, is mechanically via a finger on a disc and a crank are connected with a connecting rod and a stem rigidly fixed with a hollow element and a pipe installed inside the body.
EFFECT: compactness and reduced metal intensity with increased transforming devices, making it possible to increase coefficient of mechanical energy transformation into thermal one.
SUBSTANCE: heat generator includes a cylindrical housing, a cover plate and a bottom. Inside the housing there installed on a ring attached to the wall is a pulse speed variator having a shaft with three rows of blades, in its upper part. The cover plate is provided with an electric generator, which is mechanically connected through friction discs to a drive shaft, as well as an electric accumulator connected through leads to the generator and electric board. Under the cover plate inside the housing there installed is a tubular coil having inlet and outlet branch pipes connected to cold and hot water supply systems.
EFFECT: heat generator design is compact; it has considerable number of rotating parts, which increases its thermal efficiency.
SUBSTANCE: system includes a heat generator, in the housing of which there fixed on the shaft are two discs forming an antechamber in the housing volume, a chamber of space between the discs and a post-chamber. Location of the discs on the shaft is calculated as per a certain formula; two discs of the heat generator are filled with pressed magnets arranged in a circumferential direction; bifilar coils with working and control windings, the cores of which are put tightly into the housing, are installed above the discs. Besides, a control unit is introduced, which is arranged between working and control windings of coils; in addition, the heat generator housing volume includes an electrolyser, the pairs of electrodes of which are made of one nipple electrode, the other one that is pressed into the housing; pairs of electrodes are arranged in a circumferential direction of the housing inner volume in the space between the discs and in the post-chamber. The system also includes a gas collector of oxygen-hydrogen mixture; the heat generator inlet is connected to the receiver outlet; the heat generator outlet is connected to the gas collector, and the gas collector is connected to the receiver inlet.
EFFECT: proposed invention allows reducing power consumption for obtaining heat and generation of gases.
SUBSTANCE: heat generator is installed in a closed circuit, at which vortex flow of water is formed due to conversion of a head created with a pump and the received flow is accelerated in a water movement accelerator, with further removal of heat obtained in the heat generator from outlet water flow to the consumer. At that, at the heat generator inlet, water flow is broken with an air cavity in the zone of its phase transition, in which the impact of drops of water at its outlet in atomisation cones is provided. An air cavity is formed at the inlet of the heat generator housing, and a volute has the shape of logarithmic spiral; at that, flow of liquid from the volute to a vortex pipe is performed through the logarithmic spiral pole, and a centrifugal pump and a shutoff valve is installed between a suction pipeline and a delivery pipeline.
EFFECT: obtaining more energy-saving method and economic water heating plant.
9 cl, 1 dwg
FIELD: power engineering.
SUBSTANCE: polyfunctional step vortex heater comprises a reduction thread, connected with inlet and outlet gas lines, in which there is a gas filter, a safety stop valve, a pressure controller, a double-flow and a single-flow ribbed vortex pipes, serially connected to each other by a cold gas flow, forming separate steps closed with a board jacket, besides, the inlet nozzle of the first stage of the vortex pipe is connected with the reduction thread via a tee and a stop device, its high-temperature nozzle is connected via a cyclone to an ejector nozzle, and a low-temperature nozzle is connected with an inlet nozzle of a vortex pipe of the second stage, the high-temperature nozzle of which is connected with a receiving chamber of the ejector, the outlet nozzle of which is connected via a stop device and a tee with a gas filter of the reduction thread, and the condensate outlet from the tray of the cyclone is connected to an external collector of condensate.
EFFECT: higher reliability and efficiency of a polyfunctional step vortex heater.
SUBSTANCE: hydrodynamic cavitator has fixed working chamber shaped to elliptic torus with two focuses and rotary disc. Working medium is fed by integral centrifugal pump or independent pump unit in working chamber in small portions when openings in said rotary disc and working chamber wall get aligned. Cavitation steam-gas bubbles of boiled fluid are formed in zone of proximal focus. Collapse of said bubbles is accompanied by intensive shock wave processes and origination of superhigh pressures and temperatures. Shock waves reflect from proximal focus to working chamber wall and, further, therefrom to nearest focus, and so on.
EFFECT: increased resonance of shock waves, efficient grinding of solid particles, structural and molecular change in complex molecules and mixes, dispersion and other chemical processes.
FIELD: power engineering.
SUBSTANCE: method of heat release in a liquid is proposed, including development of cavitation, at the same time a gas cushion is developed in the liquid cavitating in the closed circuit, and its volume and flow of passing liquid are serially varied to set an autovibrating mode in it, besides, a source of oscillations is a centrifugal nozzle, and to vary a gas cushion the closed circuit is equipped with an expansion tank with a piston moving in it, besides, the smaller part of the liquid flowing along the circuit is additionally heated to the temperature close to overheating in a heat exchanger prior to arrival to a cavitator (centrifugal nozzle), and a coolant for a heat exchanger is hot water or steam or power. The method makes it possible to intensify heat release in a closed circuit, where liquid circulates due to pre-heating of the liquid prior to its supply into a cavitator (centrifugal nozzle). Pre-heating of the liquid is carried out to the temperature close to overheating.
EFFECT: more intense formation of cavitation bubbles and release of high quantity of energy as they collapse.
FIELD: instrument making.
SUBSTANCE: target goal is achieved by the fact that an inner surface of a body has a coating from metals of aluminium, copper, silver, nickel, chrome or zinc with the reflecting capacity of thermal (infrared) radiation from 90 to 99 %, and having coating surface roughness from 0.2 mcm to 3.2 mcm, and an outer surface of the body is coated with a heat insulation paint. As a result of lower heat losses to environment, intensity of liquid heating is increased by 10-15 %.
EFFECT: lower heat losses to environment and higher efficiency of liquid heating.
FIELD: oil and gas industry.
SUBSTANCE: crushed natural fuel mixed with oil slurries or acid tars, which are taken in the ratio of 1:1 to 5:1 by weight, is subject to heat treatment at temperatures of preferably 450-500°C in a drum-type reactor with external heating, which are heated with gas heat carrier so that gaseous fuel product, liquid products and solid coke-ash residue are obtained. Gaseous fuel product is supplied for combustion, and combustion flue gases of gaseous thermocracking products of raw mixture are used for heating of the drum-type reactor.
EFFECT: increasing yield of target product, enlarging range of residue oil raw material, and simplifying instrumentation.
4 cl, 2 tbl, 30 ex