TWI364504B - Piping - Google Patents

Description

1364504 IX. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to piping, and more particularly to piping for a cracking furnace. The piping can have a particular geometry. The invention also extends to various other uses of piping having this particular geometry. [First as technology] The cracking furnace is especially used in the production of ethylene. In the steam cracking process Φ of ethylene, the hydrocarbon feedstock is diluted with steam and then rapidly heated to a high temperature by passing the feedstock through a tube in the furnace (commonly referred to as a "furnace coil). The feedstock is decomposed. The effluent stream containing the pyrolysis mixture of the hydrocarbons from the pyrolysis tubes and the unreacted components of the feedstock are quenched to prevent recombination of the products. Distillation and other separation operations treat the cooling stream wherein the various products of the cracking operation are separated. Known cracking furnaces suffer from several problems due to the extremely short residence time of the feedstock and steam flowing through the tubes in the furnace (tens of minutes) One second), so the furnace and the tubes must be kept at extremely high temperatures to achieve the necessary rapid heating to achieve pyrolysis. Therefore, a large amount of fuel is required to heat the furnace. In addition, the tubes are extremely hot in the furnace. High temperatures cause coke to deposit on the tubes, which is particularly undesirable because the presence of the coke layer inside the tube reduces heat transfer from the furnace to the feedstock and thus affects the yield. The pressure drop in the S-Hay pyrolysis tube, although this factor is generally considered to be less important than the heat transfer effect. If the carbon deposition is very severe, it is usually necessary to periodically shut down the furnace (usually every 2 to 60 days) to The decoking of the tubes (for example by steam removal) 108887.doc 1364504, since each furnace represents a significant capital investment, it is necessary to minimize the downtime. [Invention] According to the present invention, a cracking furnace is provided, which is provided Having at least one pyrolysis tube through the furnace, wherein the pyrolysis tube is formed such that it has at least a portion of the centerline of the portion being three-dimensionally curved. It has been found that when fluid flows through a portion of the three-dimensionally curved piping of the centerline, A π vortex is formed along the tube (ie, a component of motion surrounds the centerline of the tube). This "eddy current" has several advantages over conventional flow. Due to the presence of eddy currents, the cross section of the tube There is an improved mixing. Furthermore, due to this mixing, the flow velocity distribution across the pipe is evenly distributed (or blunt) than the flow velocity distribution in conventional pipes, The vortex fluid tends to act as a piston to flush the walls of the pipe. Furthermore, the flow velocity near the wall of the pipe is increased compared to a straight pipe, which provides a reduced boundary layer thickness, the reduced boundary layer thickness Essentially improving the heat transfer from the piping to the fluid in the piping. The improved mixing is particularly suitable when applied to a pyrolysis tube in a furnace, as it is the fluid of the flow center and the tube The fluid between the wall fluid and the central fluid provides considerable mass, momentum, and heat transfer. Thus, there is improved heat transfer from the wall of the pyrolysis tube to the feed stream flowing therethrough. This improved heat transfer is achieved The higher yield of the final product, or will result in a reduction in the fuel consumption of the furnace to achieve the same yield. In the case where the heat transfer is a limiting factor in the furnace production capacity (usually as the case), the improved heat transfer also effectively increases the furnace. Production capacity. 108887.doc 1364504 In addition, eddy currents can reduce coking. The improved heat transfer as described above causes the pyrolysis reaction to proceed at a lower pyrolysis tube wall temperature, and this reduced temperature will result in a decrease in coking. In addition, the higher near wall flow velocity reduces the likelihood of any burnt deposit (since the coke is more likely to be cleaned by the vortex alone) and will also readily remove any coke that has been deposited on the wall. The use of eddy currents in the pyrolysis tube can be extremely important as the reduction in anaplastic deposition will increase the length of time the furnace can be used before it is required to remove carbon, and thus increase the productivity of the furnace. Preferably, the inner surface of the pyrolysis tube is substantially smooth and may, for example, be coated with a low friction layer, and layers such as It are also known. It is preferred to avoid surface features such as the reticle' which will result in a corresponding tendency for increased wetted perimeter and increased flow resistance. It is known that conventional pyrolysis tubes (straight or only two-dimensionally curved) have a double line and this can cause eddy currents to approach the inner surface of the tube. However, this is a relatively localized (near wall effect) which makes the central flow even if there is cross-mixing. Therefore, the improved heat transfer advantage β of the present invention is not obtained in a double or one-dimensional bending. The centerline is either straight or follows a two-dimensional bend. In a preferred form, the pyrolysis tube is formed such that it has at least one knife and the centerline of the 5 hai portion is formed as a spiral having a plurality of turns. If Β " & formed with a plurality of turns of the spiral (its three-dimensional bend) continues along the tube, and will continue to gain these advantages. Vortex μ is rapidly established in the middle to line three-dimensionally curved tube portion. With the center line The pyrolysis tube portion of the three-dimensional f-curve in the k-distance can achieve the above-mentioned eddy current advantage in some cases. However, if the tube then returns to a positive-facing surface having a straight center 108887.doc 1364504 line, the eddy current will It disappears and is replaced by a conventional stream. Preferably, therefore, most of the pyrolysis tube has a centerline of three flutes when passing through the furnace. For example, 'more than 5〇%, preferably more than 75%, better. The degree of tube in the furnace above 9〇% may have a 3-D bending centerline. The pyrolysis tube portion may be formed such that its helix angle is constant, and this may be desirable to simplify the manufacture of the pyrolysis tube. However, it is also possible that the curvature varies along the length of the pyrolysis tube portion. For example, the tube portion may have a plurality of components, each having a different helical curvature. Since the variable curvature allows the flow conditions to vary along the tube, For example, 'can enter The flow conditions in the tube (= the material is relatively cold and not yet cracked) at the time of the furnace are different from the conditions when the tube is removed from the furnace: where the material has been cleaved and the relative curvature of the heat is used to vary the flow conditions. Varying curvature also allows the pyrolysis tube portion to perform well in a wide range of flow conditions, for example, depending on the type of feedstock, varying with different densities, viscosities, etc. The flow characteristics of the tube portion can be varied. Optimized for the _ group specific flow shoulder to achieve the best possible result; externally, if the 4 flow conditions are different from the specific group, then the tube portion may be non-optimal. Conversely, the material curvature along the tube portion If the length changes, then one (four) - is well executed for a given group of flow conditions (even if other areas are not good) and this makes the tube part used in a larger range of flow conditions. ::, (4) The center line of the shirt. For the spiral 'if the helix angle and the value 疋' then the curvature is determined. If the curvature is to be changed in the other way, the change of the helix angle and/or the amplitude of the helix reaches 108887. Doc 1364504 Of course, other features of the tube portion other than curvature may vary along its length. These features include the area of the tube that may be determined or variable, and the cross-sectional shape of the tube. The amplitude of the spiral in this specification. Refers to the extent of displacement from the intermediate position to the lateral end. Therefore, in the case of a pyrolysis tube portion having a helical centerline, the amplitude is half the full width of the transverse centerline of the spiral. The amplitude of the spiral may be required to be relative For example, the amplitude may be greater than the inner diameter of the 9-tube portion. However, for tightness, the amplitude is preferably equal to or: the inner diameter of the tube portion. In a particularly preferred form, the tube portion is formed as Low amplitude spiral. For ''low amplitude spiral', we mean to form this portion such that its centerline advances along a generally helical path, and the amplitude of the spiral is equal to or less than one half of the inner diameter of the portion. A tube formed as a low-amplitude spiral in this manner is particularly advantageous because it provides the advantage of a thirsty brick but does not occupy a larger volume than a straight tube and is therefore available instead of a straight tube. It is especially advantageous if the tubes are used to retrofit existing furnaces with straight tubes' because these straight tubes can be simply replaced with low amplitude solenoids. Piping with this type of low-amplitude helical geometry can be used in a large number of applications other than pyrolysis tubes in cracking furnaces, and the advantages obtained by using some of it and by using low-amplitude spiral geometry will be described later. . * [Embodiment] ψ In Fig. 1, a prior art cracking furnace is indicated by the reference numeral 1〇. A burner 10812 is placed at the bottom of the furnace to heat the furnace. The hot combustion products exit the furnace via the chimney 14, and such products can be used to preheat the feedstock and the steam used in the pyrolysis reaction. - The pyrolysis tube enters the furnace at the bottom of the furnace (as indicated by reference numeral 20). The pyrolysis tube extends upwardly through the furnace (reference numeral 22) and pyrolysis occurs in this portion of the tube. The tube exits the furnace (reference numeral 24) and carries the pyrolysis reaction product and any unreacted feed to a quench unit.

The official is formed into a generally straight pipe. The elbow in the tube is a simple planar right angle elbow in which the centerline in the tube is only two-dimensionally curved. In practice, a large number of pyrolysis tubes will pass through the furnace; however, for the sake of clarity, only a single tube is shown. In some prior art configurations, the pyrolysis tube has a "u" or "W" configuration' and called the coil, μ coil, * coil. Form the "U" or "Μ" in the case of the condition of the "w" in the shape of the elbow in the early morning Figure 2 shows a furnace which is not according to an embodiment of the invention, corresponding to the furnace of the furnace, etc. The p-pieces have the same reference numerals. Moreover, for the sake of clarity, only one single/one is shown. (solid pipe. In this paper, the edge of the pyrolysis tube 3〇 forms a center line of three-dimensional bending. In detail, it is formed as a spiral having a vertical ^ from the bottom of the furnace to the top (due to the spiral of the pyrolysis tube) Shown in a side view 'so it is presented in the form of a pyrolysis tube as shown in the schematic and the pyrolysis tube can be formed in a variety of ways different from the figure i088S7.doc 丄北4504 because the hot material 30 forms a three-dimensional f curve The centerline, so the mixture of raw material and steam in the pyrolysis tube follows the pyrolysis A flow of thirst will occur as it flows. This will result in a mixture of the modified feedstock and steam, and will also improve the heat transfer from the wall of the pyrolysis tube through the mixture. Thus the wall of the pyrolysis tube can be compared The temperature at which the wall temperature is low when the flow does not form eddy currents causes less burner fuel to be consumed. This lower wall temperature will also extend the life of the furnace tube and in some cases allows the use of cheaper alloys and the intended use In addition, the lower pyrolysis tube wall temperature and the increased near-wall flow velocity reduce the amount of coke deposited on the pyrolysis tube, and since #近(四) flows faster 'so any deposition The coke can be removed from the wall. This reduction in coking is particularly advantageous as it ensures good heat transfer characteristics. It also reduces the need for furnace shut-down. In Figure 2, part of the tube enters the furnace. The front display is straight; however, this portion can also form a centerline of the three-dimensional bend, and this portion can be helical along its length. The spiral portion of the pyrolysis tube 30 in Figure 2 is shown to be quite similar to the coil. Shape ^, this makes The "closed zone" of the pyrolysis tube is relatively wide and also significantly increases the length of the tube (and therefore the residence time). Such special U may, in some cases, be undesirable, and thus the helical portions are preferred. Form 4 is a low-amplitude spiral 'where the tube is formed such that its centerline is advanced along a substantially selective path, and the amplitude of the helix is equal to or less than one-half of the inner diameter of the tube. The term "spiral amplitude" as used herein refers to The centerline is moved from the intermediate position I08887.doc 1364504 to the lateral end. The amplitude is therefore one-half of the full width of the helical centerline. In this type of low-amplitude helical portion, where the amplitude of the helix is less than the tube Half of the inner diameter, there is a "line of sight along the lumen that even though the flow of sight can potentially advance along the straight path, it has been found to have a swirl component. The relative amplitude " of the helical portion is defined as the vibration p divided by the inner diameter. Since the amplitude of the spiral tube is less than or equal to half the inner diameter of the tube, this means that the relative amplitude is less than or equal to 〇5. The relative amplitude of less than or equal to 〇 45, 0·40 '0·35, 0·30, 〇·25, 〇 2〇 ' 〇 15, 〇 or 〇 〇 5 is preferred. The smaller relative amplitude provides better utilization of the available side space since the tube is not completely wider than a standard straight tube having the same cross-sectional area. The smaller relative amplitude also results in a wider gaze, providing a larger space for insertion of a pressure gauge or other device along the tube (which may be useful when cleaning the tube). However, very small relative amplitudes may result in reduced first motion and mixing in some cases. For higher Reynolds numbers, a smaller relative amplitude can be used while the eddy current is directed to a satisfactory range. This will generally mean (for a given inner diameter) that in the presence of a high flow rate, a low relative amplitude can be used while still being sufficient to cause eddy currents. The helix angle (or spacing 'where the spacing is the turning length of the helix and may be defined by the inner diameter of the tube) is also a relevant factor affecting the flow. For relative amplitude, the lead angle can be optimized according to conditions. The helix angle is preferably less than or equal to 65. 'More preferably less than or equal to 55. 45. 35. 25. 2〇. 15, 15. , 10. Or 5〇. 108887.doc 1364504 In general, for higher Reynolds numbers, the helix angle can be smaller while achieving a satisfactory eddy current, while for lower Reynolds numbers, a higher helix angle would be required to produce a full In the case of the German (four) spin, the use of a higher screw angle for faster flow (having a higher Reynolds number) would generally be undesirable, as there may be pockets of fluid near the wall stagnant. Therefore, for a given Reynolds number (or Reynolds number range), it is preferred to select the lowest possible helix angle to produce a satisfactory vortex. In some embodiments the helix angle is below 2 〇. . The length of the pipe with a low amplitude spiral geometry is shown in Figure 3. The tube has a constant thickness P, 100 having a circular cross section 'one outer diameter De, one inner diameter 〇1 and the tube is rolled into a constant amplitude A (as measured from the middle to the end), a constant helix angle Θ and a sweep Sweep the width of the spiral. The tube 1 is contained in a longitudinally extending virtual enclosure 12 且 and has a width equal to the sweep width of the spiral. The enclosed area 12A can be considered to have a central longitudinal axis 13A, which can also be a helically rotating shaft. The tube of the description! (10) has a constant axis 13〇, but it should be understood that the central axis can be bent, or even any shape can be presented as desired. The tube has a - follow-up path to read the (6) 3 () of the towel core, line 14 〇. It should be seen that the amplitude A is less than one half of the inner diameter Di of the tube. By maintaining the amplitude less than this size, the side space occupied by the tube and the overall length of the tube can be kept relatively small while the helical configuration of the tube causes fluid to form eddy currents along the tube. This also provides a relatively wide cavity along the tube that allows the appliance, device and the like to pass through the tube. /4 exhibition does not - group pyrolysis (four), all of these tubes are formed into low amplitude spiral tubes. It will be appreciated that in practice such pyrolysis tubes will be formed in this manner as a group to provide higher throughput at a short dwell time while still providing sufficient heat transfer to the feedstock to cause pyrolysis to occur. The pyrolysis tubes shown in Figure 4 are in the shape of "u". Each tube has an inlet port 4, an outlet portion 42 and a "U" f head portion 44 having a two-dimensional curved inlet portion 40 having a short portion straight tube 46' followed by a "u" elbow portion: It is also two-dimensionally curved. This is inserted into the three-dimensional curved portion 5〇, the downstream end of which is connected to the "u"f head portion 44. The second three-dimensional curved portion 5() carries the fluid to the outlet portion 42' which has "u"f head portion 52 and then short portion straight tube. The two two-dimensional curved "U" _ head portions 48, 52 and the "U" f head portion 44 ^ are curved in two dimensions to facilitate manufacturing and installation And in this case, the pyrolysis tube enters the furnace at the bottom of the furnace and exits at the top thereof. Figures 5a and 5b are schematic diagrams of alternative configurations of the pyrolysis tubes 3〇 In each case, the centerline 14〇 (as described in relation to Figure 3) is helical. In Figure 5a, the pyrolysis tube enters the top of the furnace and extends down to the bottom of the furnace. Surround, extend to the top of the furnace and leave. Therefore the tube is usually in the shape of "U"-. In this case, Figure 3 The helical rotation of the shaft 13 "U ,, - shaped. In Figure 5b, the tube 3 does not exit immediately at the top of the furnace, but instead forms another downward and upward circuit and exits at the top of the furnace. Therefore, the tube is hanged as W inflammation. In this case, the axis of the spiral rotation described with respect to Figure 3 should be "W"-shaped. Of course, this particular configuration of the tube will depend on the particular requirements' and it should be understood that other shapes of the pyrolysis tube and other points of entry and exit from the furnace may be used depending on the particular requirements. ~ The use of low amplitude spiral geometry is not limited to pyrolysis tubes in cracking furnaces. Pipes having a low-vibration spiral geometry (which may have characteristics along the length of 108887.doc 1364504) may also be used in a number of processes, including movement or transport of fluid through the pipe, mixing of fluids in the pipe, tubes The volume and mass of the medium fluid are transferred into or out of the process, "the process of deposition or contamination occurs, and the process in which the pipe occurs. This application can be applied to a gas or liquid as a single phase: or as a multiphase mixture. A mixture of gases, liquids or solids. The use of this pipe can have important economic effects.

As an example, thirst flow can provide a reduction (4) and a reduction in the associated reduction, which would reduce pump costs under appropriate conditions. This can be important for the distribution of hydrocarbons in the pipeline, including crude oil and gas generation processes. For example, a petroleum manufacturing riser and flow line for domestic or foreign use may include at least a portion having a low amplitude helical geometry. The low amplitude spiral geometry improves the flow of the riser or flow line: power ’ because it reduces flow turbulence through the flow line or riser and thus reduces pressure loss. The flow line or riser can be substantially vertical, generally horizontal 'or have a curved geometry' including s, or a catenary shape. The flow line or riser can be rigid or flexible, or any combination of the two. The flow line or riser is constructed of any combination of materials and may include a reinforcement ring. A low-amplitude spiral geometry can be used similarly in the manufacture of oil wells, gas wells, wells or geothermal wells for use in wells. At least a portion of the well will have a manufacturing tube with a low amplitude spiral geometry. These advantages will include reduced flow turbulence and reduced pressure loss. In addition, the pipeline for transporting hydrocarbons can use a low amplitude spiral geometry and will afford the benefits of reduced flow turbulence and reduced pressure loss. When 108887.doc 1364504 w 'the pipeline for conveying other fluids may also have a low amplitude spiral geometry and achieve the same advantages 'such fluids as drinking water, waste water and sewage, slurry, powder, food or beverage, or even Any single or multiphase fluid.

Other areas where this reduced pressure drop is particularly beneficial are in the case of indenter lines and draft tubes for hydroelectric applications. Reduced pressure loss will result in increased power output, and even a small drop in pressure drop can result in a significant increase in power output over the life of the device. • It is also important to reduce the pressure drop in the steam distribution of power stations and other industrial equipment. Also important is the need to maintain the pressure at the lowest possible level to improve the yield of chemical reaction operations, including processes operating under vacuum, such as by pyrolysis (as discussed in detail above) to produce olefins and ethylbenzene benzene. Ethylene. Mixing in piping is important in many industries including the chemical industry, the food industry, the pharmaceutical industry, and the petroleum industry. It is often important to distribute a small amount of active chemicals in a large number of other substances. In some cases, this is called ingredient. Examples may be the addition of antioxidants to a variety of substances and foods and the addition of air to drinking water. Since the low amplitude helix provides an inherently good mixing, it can reduce the amount of active chemical that ensures a concentration sufficient to achieve the desired purpose' and ensures that no local B: additive concentration is present. Mixing (or low) Mixing is also important when it is necessary to combine two or more fluids and ensure that they are not. Keep the fluid in a stable mixture. Prevent the undesired phase separation. Mix it into the desired one. This is important on _ oil and gas, = I08887.doc 17 1364504 is a plug flow that reduces line capacity and increases operating costs. Even the use of low-amplitude snail 9 geometry in petroleum manufacturing risers and flow lines, manufacturing tubes and feedstocks for in-well use, and other fluid t-lines are preferred for plug flow reduction. This improved phase mixing is also important in the f-line because it tends to retain gas or air in the fluid rather than causing gas or air to be at the high point of the tube and may cause a gas plug. Mixing is also important when the solids are transported by the liquid to prevent the solids from precipitating, such as by the pipeline to transport sewage or minerals during the mineral extraction process. This reduction in precipitation (and demineralization of mineral and/or hydrocarbon deposits) is also important for petroleum manufacturing risers and flow lines and for manufacturing tubes for in-well use. The reduction in precipitation is also important in hydropower applications. In addition, this improved blending reduces the risk of water reversal in petroleum manufacturing risers and flow lines and in the use of wells for use in wells. As an example, static mixers for chemical compounding and food processing, chemical processing, petroleum processing, and pharmaceutical processing can employ low-amplitude spiral geometries. These advantages will include increased cross-mixing and reduced blockage caused by sedimentation. Moreover, as described above, the low amplitude helical geometry will also provide reduced mixer pressure loss. In addition, cleaning is easier because there is a line of sight along the helical portion of the low amplitude and there are no baffles or vanes commonly found in conventional mixers. These advantages will result in reduced maintenance and wear. In addition, the improved mixing (in detail thermal mixing) and the reduced pressure loss that can be achieved using low-amplitude helical geometry are particularly beneficial for heat exchangers for power stations, cooling cold boxes, air separation cold boxes and the like. . 108887.doc -18· 1364504 Low-amplitude spiral piping can also be used to ensure complete mixing of components prior to reaction. This will ensure that the reaction proceeds more completely and efficiently. Typically this will involve mixing the gaseous or liquid reactants prior to passage through the catalyst. However, it is contemplated that this can be used to mix the fuel with air prior to being fed to the internal combustion engine. This will improve the efficiency of the internal combustion process and reduce the unburned or sent to the atmosphere.

Partially burned fuel and fine solids. This final improvement will also reduce the need to improve the performance of downstream catalytic converters for internal combustion engines used in road transport and thereby improve the performance of downstream catalytic converters for internal combustion engines used in highways. Since the low-amplitude spiral pipe ensures a spiral (vortex) flow in the pipe and produces a relatively blunt velocity profile, the internal fluid velocity of the pipe and the uniformity of heat transfer to or from the fluid can be improved. In a conventional flow, the fluid movement at the center of the pipe is significantly faster than the flow near the wall of the pipe, and thus if the pipe is heated, the fluid near the walls will be heated to a higher level than the fluid near the center of the pipe. degree. However, the P vortex has a blunt (and therefore more uniform) velocity profile,

Therefore, the fluid portion will be less likely to be overheated or underheated, resulting in undesirable effects. The low amplitude spiral pipe allows the same heat to be transferred between the inside and the outside of the pipe with a small difference in temperature. This may be particularly beneficial when a portion of the fluid t is added to the fluid and is treated in a manner (e.g., plus, ,, ). If the right side is not suitable, then the part of the mixture that is running fast will be under-processed, and the part of the mixture that is transported by _ 将 will be over-processed, however, the low-amplitude spiral geometry provides a good mix. : This avoids the 'and achieves a more even-processing. This is usually used for furnaces such as oil 减 减 '" furnaces, for preheating furnaces or visbreakers for refinery thermal cracking equipment I08887.doc -19-1364504, for the power plant, for power generation Station heat exchangers, cold boxes for industrial cooling units, cold boxes for air separation units and cooling units are often important economic benefits. This blunt, speed fractional map is also beneficial in hydroelectric applications. When the velocity profile (4) phase turbine is easy to work well, and thus the use of the low amplitude cyclone portion in hydroelectric power generation can improve efficiency in this manner. Other advantages of thirsty flow in hydropower applications include reduced vacancies and reduced piping stress. In addition, the "piston" aspect of eddy currents produced by low-amplitude spiral piping can provide significant economic benefits to the processes occurring in the piping, which are the deposition of fine particles or their solid particles on the inner wall of the piping. A barrier that creates heat transfer, or a flow through which the pollution flows, or reduces the flow of fluid through the conduit. The fine particles or other solid particles may be present in the fluid or may be formed by a chemical reaction between the constituents.

It is desirable that the use of low amplitude spiral piping significantly reduces the solids deposited on the inner wall of the piping' thus extending its pre-cleaning operating life, reducing the amount of heat required, and reducing the pressure drop compared to contaminated piping. An effect of this may be an economically important example of the transport of solids in a liquid line, and also the production of ethylene by pyrolysis as detailed above. - Similar effects occur in other furnaces such as preheating furnaces for refining waste processes. In addition, the blunt velocity profile and the "piston" aspect are extremely useful in batch processing, and are common in pharmaceutical processing and food processing. Due to the blunt velocity profile, the potassium dispersion of the batch can be reduced, and peak concentrations are much easier to achieve than conventional configurations. These 108887.doc •20· 1364504 features are particularly beneficial if the batch size is small. In addition, the "Piston Flow" facilitates the removal of traces of the first component from the #-pipe wall following the second component, which helps to reduce the chance of contamination in batch processing. The time required to wash the system, along with the amount of fluid required to perform the cleaning, can be at least reduced. In the case where a chemical reaction occurs in a pipe or tube, the use of a low-amplitude spiral pipe can also have substantial economic significance. The combination of improved mixing and more uniform heat transfer will improve yield and promote complete (including combustion) beta improvement. Yield will also reduce downstream separation costs. This will be an important example process including ethylene production and similar gas phase reactions such as toluene cracking to benzene and butene-1 to butadiene. In the case where the reactions include the formation of more than one product molecule by each of the feedstock molecules, the lower pressure drop in the reactor and its downstream piping engineering by using low-amplitude spiral piping provide other advantages from this lower average pressure' This will reduce the likelihood of product reconstitution to form a feedstock or other non-desired by-product. In addition, it is particularly important in the petrochemical industry to make low-amplitude helical geometry in reactors for chemical applications, petrochemical abuse, and pharmaceutical applications, which can, in reactor tubes, reduce deposition. The mixing of the sacred menstruation and the more uniform heat transfer will also promote the complete combustion reaction in the absence of a large excess of air (the amount required for reaction stoichiometry). This is especially important for incinerators or waste treatment furnaces where it is necessary to ensure that the entire combustion is carried out to prevent chemical/particles that are harmful to the environment and human health from entering the atmosphere. This is ensured by ensuring that the combustion gas flows through the piping portion formed into the low-amplitude spiral before it flows into the winter air. Producing vortices through the furnace will increase the rate and efficiency of combustion and waste removal. 108887.doc 1364504 When the low amplitude helical portion is used with a fluid comprising two or more different phases, it can additionally be used to " separate < separate fluid mixtures having different densities. The eddy current generated by the spiral flow tends to make the mixture relatively dense due to the centrifugal effect, and the tributary component moves toward the pipe walls and moves the lower density component toward the center line. With a suitable configuration, the higher (or lower) density components can be excluded leaving the remaining components present in increasing concentrations. This process can be repeated using other in-line static separators. This separation can be used to remove gas from φ liquid + and can therefore be used to help reduce gas plugs, especially in the petrochemical industry. A method similar to this can be used to increase or decrease the concentration of particles in the flowing fluid. This will be achieved by removing fluid from adjacent to the tube centerline or from near the tube wall. In addition, eddy currents caused by low amplitude, helical portions can be used to remove particulate matter from the fluid. This is especially important in, for example, air intakes. The intake ρ is used in many situations where air is required, and in particular requires air to burn and/or cool the vehicle. Helicopter sigma usually requires dust separation to prevent dust from reaching the engine, and the vortex generated by the low-vibration spiral geometry can be used to separate the dust from the gas stream without separating the damper. Furthermore, it has been found that the eddy current caused by the low-amplitude helical portion continues to be piped and downstream for a distance in the portion. Thus, a portion of the low-amplitude auger tube can be inserted upstream of a structure such as a f-head, a τ- or γ-joint head, a manifold, and/or a change in cross-section of the conduit, wherein the vortex produced by the low-amplitude helical portion will inhibit fluid Separation, stagnation, fluid instability, benefiting the cost:: Corruption and wear in the tube. The vortex in the boring head, the joint head or the like is characterized by a reduced fluid separation, resulting in reduced pressure loss, reduced deposition and precipitation, reduced cavitation and increased Fluid stability. The low-amplitude spiral geometry piping located in front of the elbow will also reduce particle erosion in the pipe elbow, which is especially beneficial for power plant fuel supplies. Thus, it will be apparent to those skilled in the art that piping having a low amplitude helical geometry can provide a number of advantages in many situations. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective view of a prior art cracking furnace; FIG. 2 is a schematic cross-sectional view of a cracking furnace according to a first embodiment of the present invention; Figure for the length of a tube of amplitude spiral geometry; Figure 4 is a diagram of a set of pyrolysis tubes using a low amplitude spiral geometry; and Figures 5a and 5b are crackers of an alternative configuration using a low amplitude spiral geometry Schematic cross-section. [Main component symbol description] 10 Cracking furnace 12 Burner 14 Chimney 30 Pyrolysis tube 40 Inlet part 42 Outlet part 44 "U" Elbow part 46 Short part straight pipe 48 "U" Elbow part 108887.doc •23 1364504 50 three-dimensional curved part 52 "U" elbow part 54 short part straight pipe 100 pipe 120 closed zone 130 central longitudinal axis 140 center line

108887.doc

Claims (1)

Patent Application No. 095108415 (Related Patent Application No. 095108415) (December 101) Deduction Day 10, Patent Application Range: 1. A cracking furnace having at least one pyrolysis tube passing through the furnace, the pyrolysis tube defining a a flow path having a substantially circular cross section, wherein the flow path of the substantially circular cross section has at least one pyrolysis tube portion having an inner diameter, the pyrolysis tube portion having a spiral center line having an amplitude and The three-dimensional direction is curved ' and wherein the amplitude of the spiral centerline is less than or equal to the inner diameter of the pyrolysis tube portion. 2. The cracking furnace of claim 1, wherein the curvature of the centerline varies along the length of the pyrolysis tube portion. 3. The cracking furnace of claim 1 having a portion having a helical curvature that provides a flow state in which the tube enters the cracking furnace and the portion having a helical curvature provides a different flow state in which the state The tube is left in the furnace. 4. The cracking furnace of claim 1, wherein the inner surface of one of the pyrolysis tube portions is substantially smooth without surface features. 5. As requested! The cracking furnace wherein the cross-sectional area of the pyrolysis tube portion varies along its length. 6. The cracking furnace of claim 1, which is divided into a portion having a spiral center line. 7. The cracking furnace of claim 6, wherein the pyrolysis tube has a U shape, and the portion of the towel having a straight line to the line is The portion of the pyrolysis tube straight, said & 1 and having the 8. center line in the spiral is the other leg of the u-shaped pyrolysis tube. The cracking furnace of claim 7, wherein the pyrolysis tube elbow portion is combined. The leg system is a two-dimensional 108887-1010120.doc year. '丨月修修(more) is replacing page 9_如·: The pyrolysis furnace of the monthly item 1, wherein the amplitude of the spiral center line is less than or equal to one half of the inner diameter of the pyrolysis tube portion to The flow path defined by the unwinding section provides a line of sight. 10. The cracking furnace of claim 1 wherein the amplitude of the helical ten-heart line is greater than or equal to one-half of the inner diameter of the portion of the pyrolysis tube. 11. The cracking furnace of claim 10, wherein the spiral centerline has a helix angle of less than or equal to 20°. 12. The cracking furnace of claim 1, wherein the pyrolysis tube is supported while it enters the furnace and exits the furnace, and the other portions are unsupported. 13. A cracking furnace having at least one pyrolysis tube therethrough, wherein the pyrolysis tube boundary is a first-class road having a cross section, the cross section being substantially circular, wherein the flow path having the substantially circular cross section has at least a pyrolysis tube portion having an inner diameter, the pyrolysis tube portion having a helix center line having an amplitude and curved in a three-dimensional direction, wherein the amplitude of the spiral center line is less than the inner range of the $ ¥ $ portion, And wherein the spiral center line has a helix angle less than or equal to 45°. 108887-10l0120.doc