Apparatus and method for thermal decomposition of fluid hydrocarbons

Abstract

The present invention relates to an apparatus for thermally decomposing a fluid hydrocarbon into one or more hydrocarbon products, comprising: at least one recycle pump for transporting the fluid hydrocarbon; and at least one recycle heat exchanger providing at least one tube through which the fluid hydrocarbon passes; wherein at least one recycle pump and / or recycle heat exchanger is configured to establish a flow velocity of at least 1 m / s of the fluid hydrocarbon in at least one tube.

Description

Detailed Description of the Invention

[0001] [Field of the Invention] The present invention generally relates to a method and apparatus for treating waste plastics using pyrolysis, and to products obtained by such methods and apparatus. More particularly, the present invention relates to an apparatus and method for further cracking thermally cracked temperature fluid hydrocarbons.

[0002] [Background of the Invention] Large amounts of waste plastics are generated in modern society. Plastic recycling is becoming more efficient and effective, but still many waste plastics cannot be effectively or efficiently recycled, are disposed of in landfill sites where they take years to decompose, or are released into the environment and can damage the ecosystem.

[0003] However, plastic materials are made of essentially useful compounds that can be used as such and / or converted for (re)use. For example, fuels such as diesel may be derived from waste plastics, or waste plastics may be converted into raw materials suitable for the synthesis of new materials such as new plastics, other hydrocarbon materials, or the like. Materials recovered from waste plastics can be useful for at least partially replacing hydrocarbons more traditionally obtained from natural gas or mineral oil.

[0004] The products of plastic-chemical plants are typically liquids at 25°C and contain hydrocarbons that are optionally recovered in fractions such as light hydrocarbon fractions (LHC) and heavy hydrocarbon fractions (HHC), char, and non-condensates (gases). Currently, liquid hydrocarbon fractions, LHC, HHC, or mixtures thereof are the most desirable products, but are market-driven.

[0005] LHC and HHC fractions are required by industry to meet certain chemical and physical specifications, such as vapor pressure, initial boiling point, final boiling point, flash point, viscosity, cloud point, and cold filter clogging point. While various qualities may be desired by different consumers or end-users, it is important for plastics-chemical plants to produce products of consistent quality. The final quality of the product fraction is controlled by distillation columns, such as well-known ones, and is commonly used in the petrochemical industry. It is desirable that the fractions be relatively pure so that light and heavy hydrocarbon fractions do not contain large amounts of high-boiling-point compounds. Such high-boiling-point compounds can raise the cold filter clogging point and cloud point, which are often unacceptable to purchasers of pyrolysis oil.

[0006] In plastics chemical plants, supply material plastics, which may include most polyethylene and polypropylene from domestic sources, form the input raw materials. These plastics, then composed of very long-chain hydrocarbons, are cracked into shorter chains to form a wide range of molecules with varying chain lengths. These mixtures can be distilled into various temperature-determined fractions, as is well known.

[0007] A process known in the art for converting waste plastics into diesel, in particular, is the thermochemical decomposition process of pyrolysis. Pyrolysis is the thermal decomposition of waste plastics in an inert atmosphere. In effect, the long polymer chains of the plastic polymer are cracked through heating, resulting in shorter hydrocarbon chains, which are generally more useful as products.

[0008] Pyrolysis is a preferred method for the thermochemical decomposition of waste plastic materials. Various attempts have been made to provide technically and cost-effective pyrolysis of waste plastics.

[0009] Technically useful results have been achieved by the technologies discussed in U.S. Patent Application Publication No. 2018 / 0010050(A1) and International Publication No. 2021 / 053139(A1), the contents of which are incorporated herein by reference.

[0010] U.S. Patent Application Publication No. 2018 / 0010050(A1) describes a method for recovering hydrocarbons from plastic waste by pyrolysis without the use of a catalyst, particularly from polyolefin-rich waste. The process includes the steps of melting the plastic waste in two heating devices and mixing a flow induced from a cracking reactor with the incoming molten plastic waste of the first heating device. The heated molten plastic is passed through a cracking reactor, where the plastic material is cracked. The cracked material is then distilled into diesel and low boilers.

[0011] International Publication 2021 / 053139(A1), which offers several advantages to U.S. Patent Application No. 2018 / 0010050(A1), describes, among other things, a method for breaking down long-chain hydrocarbons from plastic-containing waste, comprising the steps of: preparing a material containing long-chain hydrocarbons; heating a specific volume of the material containing long-chain hydrocarbons to a cracking temperature, at which the hydrocarbon chains in the material begin to crack into shorter chains; and, with respect to a specific volume having a temperature above the cracking temperature, exposing a specific volume to heat at a temperature less than or equal to 50°C higher than the temperature of the specific volume. After the specific volume of material has been exposed to heat, International Publication 2021 / 053139(A1) describes passing a partially cracked flow of molten plastic through a gas-liquid separation structure. The separation structure, also called a reactor, includes a separation zone containing a gas-liquid phase boundary and a sedimentation zone for accumulating heavy hydrocarbons and / or char particles, as well as potentially other solids such as aluminum, sand, and mud.

[0012] European Patent No. 2876146 describes a tested technique for recovering hydrocarbons from polyolefin plastic recyclable material using pyrolysis cracking, comprising the steps of introducing the plastic recyclable material into a mixing tank under an inert gas and mixing it with diesel oil; removing steam from a first heating zone; removing acidic gases from a second heating zone; liquefying any plastic recyclable material that is not yet molten in a third heating zone; cracking the plastic recyclable material in a cracking reactor at approximately 400 degrees Celsius; partially condensing to prevent the release of paraffins; and fractional distillation of the cracked product.

[0013] The overall objective of the present invention is to improve the entire system of such pyrolysis processes and apparatus, but the embodiments of the improvement may preferably include one or more of the following:

[0014] [overview] The present invention is defined in the independent claims, but further aspects of the present invention are described in the dependent claims, the accompanying drawings, and the following description.

[0015] In one embodiment, an object of the present invention is to provide alternative, preferably improved, examples of pyrolysis processes and apparatus. These may address systems for separating gaseous, liquid, and solid particles in plastic cracking streams, and / or for cracking long-chain hydrocarbons. An object of the present invention is also to provide improved methods for breaking down long-chain hydrocarbons.

[0016] In another aspect of the present invention, it is desirable to improve the reliability of the process.

[0017] In another aspect of the present invention, it is considered desirable to improve or limit the downtime of the system.

[0018] The features and advantages of this invention will be understood by referring to the following drawings. [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows an assembly for cracking long-chain hydrocarbons. [Figure 2] This is a schematic diagram showing the reheating and recycling loop of the separator container. [Figure 3] This figure shows one embodiment of a separator container and a recycling loop. [Figure 4] This figure shows one embodiment of a separator container and a recycling loop. [Figure 5] This figure shows one embodiment of a separator container and a recycling loop.

[0020] [Description and exemplary embodiments] For the sake of simplification and clarity of the examples, it will be understood that, where appropriate, reference numerals may be repeated in the figures to indicate corresponding or similar elements or steps. In addition, numerous specific details are given to provide a complete understanding of the embodiments described herein. However, it will be understood by those skilled in the art that the embodiments described herein can be carried out without these specific details. Furthermore, this description is not intended to limit the scope of the embodiments described herein in any way, but rather to simply describe examples of how various embodiments described herein can be realized. The following is a description of a particular embodiment of the present invention, given merely as an example and with reference to the drawings.

[0021] Figure 1 shows an apparatus comprising a heating device 11 and a separator container 12. The heating device 11 communicates with the separator container 12 to supply fluid (liquid and gas) into the separator container 12. More specifically, the heating device 11 supplies fluid containing hydrocarbons (partially) cracked in both gaseous and liquid states to the separator container 12 at its thermal decomposition temperature.

[0022] Before further describing the details of the embodiments shown, a general aspect of the present invention is disclosed below. In order to operate a plastic-chemical plant advantageously, the maintenance cycle should be extended and the maintenance downtime should be shortened. In order to extend the maintenance cycle of a pyrolysis plastic-chemical plant, it is not only important to reduce the accumulation of heavy hydrocarbons and carbon solids, but also to avoid fouling of heavy hydrocarbons, char particles, and / or solid carbon, as well as potentially other solids, such as aluminum, sand, mud, etc. in the plant's piping. The inventors have noticed that heat exchangers are particularly prone to fouling for two reasons: First, the heat exchanger cracks plastics and / or hydrocarbon chains, thus constituting a first location where any such solids can accumulate and potentially form fouling. Second, in order to increase the surface-to-volume ratio of the fluid hydrocarbon, the single stream of the fluid hydrocarbon is split into several, often increasing the cross-section of the flow. The inventors understand that the increased cross-section corresponds to a reduction in the flow rate of the fluid hydrocarbon within the heat exchanger.

[0023] According to one aspect, an apparatus for pyrolyzing a fluid hydrocarbon into one or more hydrocarbon products comprises - at least one recycle pump for sending the fluid hydrocarbon; and - at least one recycle heat exchanger providing at least one tube through which the fluid hydrocarbon passes comprising; At least one recycle pump and / or recycle heat exchanger is configured to establish a flow rate of at least 1 m / s of the fluid hydrocarbon within at least one tube. Such a flow rate helps to maintain solid particles in suspension while passing through the recycle heat exchanger. These solid particles then are less likely to settle and less likely to foul within the heat exchanger. In various embodiments, this reduces the downtime of the system or a part thereof. Although particularly described by reference to the recycle loop, the present invention is also applicable to other sections of an apparatus for pyrolyzing a fluid hydrocarbon in general.

[0024] In this regard, when the waste plastic material begins to crack, some of the shorter chains of hydrocarbons may change to the gas phase, while the longer chains of hydrocarbons remain in the liquid phase. Thus, the fluid hydrocarbons derived from the plastic material contain both hydrocarbons in the gas phase and hydrocarbons in the liquid phase.

[0025] In various embodiments, the recycle heat exchanger comprises a heat exchange surface with which the fluid hydrocarbons come into contact as they pass through the recycle heat exchanger, and the heat exchange surface has a minimum heat exchange surface area of at least 8 m 2 per 6000 kg / h of a predetermined throughput of fluid hydrocarbons passing through the operating recycle heat exchanger.

[0026] In various embodiments, the apparatus further comprises - a recycle inlet arranged to receive the pyrolysis temperature gas and the fluid hydrocarbons from at least one recycle heat exchanger; - an upper outlet for discharging the gaseous material; and - a lower outlet for discharging the fluid hydrocarbons and comprises a separator vessel, and the lower outlet is configured to pass the fluid hydrocarbons to at least one recycle pump.

[0027] In various embodiments, the separator vessel further comprises a separator vessel inlet arranged to pass fresh pyrolysis temperature feed gas and fluid hydrocarbons into the separator vessel; the recycle heat exchanger comprises a heat exchange surface for the fluid hydrocarbons to come into contact as they pass through the recycle heat exchanger, and the heat exchange surface has a minimum heat exchange surface area of at least 80 m 2This provides the minimum heat exchange surface area, which is essentially equivalent to the minimum heat exchange surface area described above, but with reference to the throughput of the separator vessel. The throughput of the separator vessel and the throughput of the recycle loop are in a relatively constant ratio, where the throughput through the recycle loop is at least 8 times, in terms of weight, the throughput of the fresh supply fluid hydrocarbon to the separator vessel, but preferably between 10 and 20 times, in terms of weight. In various embodiments, the temperature of the fluid hydrocarbon passing through the recycle heat exchanger then rises between 3°C and 15°C in a single pass, preferably between 4°C and 14°C, and more preferably between 5°C and 13°C.

[0028] In various embodiments, the apparatus is configured such that the flow rate ratio of the fluid hydrocarbon entering the separator container through the separator container inlet to the fluid hydrocarbon exiting the separator container through the lower outlet is between 1:1 and 1:20.

[0029] In various embodiments, at least one recycling pump is equipped with a fluid hydrocarbon inlet, and the separator vessel is configured to have an upper level of fluid hydrocarbons at least 7 meters above the fluid hydrocarbon inlet.

[0030] In various embodiments, the apparatus includes a recycling piping configured to pass fluid hydrocarbons from the lower outlet of the separator vessel to at least one recycling pump, and the recycling piping is configured to cool the fluid hydrocarbons as they pass to the at least one recycling pump.

[0031] In various embodiments, the apparatus comprises a carbon release point configured to dispose of heavy hydrocarbons, char particles, and / or solid carbon from a separator vessel; and a carbon release density sensor adjacent to the carbon release point configured to determine the density of a certain volume of hydrocarbons in the separator vessel adjacent to the carbon release point; the carbon release point is configured to selectively dispose of heavy hydrocarbons and / or char particles according to the density of a certain volume of hydrocarbons. In various embodiments, the density difference between the recycle loop and the carbon release point indicates the occupancy rate of char particles in the hydrocarbons at the carbon release point. This is because various compositions of hydrocarbons can result in various densities of hydrocarbons in the separator vessel. Therefore, measuring the density only at the carbon release point may yield very different values, independent of the occupancy rate of char particles at the carbon release point. The density of hydrocarbons in the recycle loop has been observed to provide a sufficient indicator of the density of the bulk hydrocarbons in the separator vessel. A comparison of the density at the carbon release point and the density in the recycle loop provides, or at least provides, a rough estimate of the occupancy rate of heavy hydrocarbons and / or char particles accumulated at the carbon release point. In various embodiments, the frequency of carbon emissions at the carbon emission point is regulated according to the density difference between the recycling loop and the carbon emission point. In various embodiments, heavy hydrocarbons and / or char particles are emitted when the density difference between the recycling loop and the carbon emission point exceeds a threshold.

[0032] In various embodiments, at least one recycling heat exchanger is configured to expose the fluid hydrocarbons to a temperature up to 50°C higher than the temperature of each fluid hydrocarbon, preferably up to 30°C higher, more preferably up to 20°C higher, and most preferably up to 15°C higher. Such limited heating has been shown to create a small amount of fouling, thus helping to extend the maintenance cycle. This helps to avoid downtime for the separator vessel and the recycling loop.

[0033] In various embodiments, the apparatus includes a back pressure control element configured to maintain the fluid hydrocarbon in at least one recirculating heat exchanger at a pressure of at least 2 bar, preferably at least 5 bar, and more preferably at least 15 bar, the back pressure control element preferably located downstream of the recirculating heat exchanger. At higher pressures, the fluid hydrocarbon is less likely to change into the gas phase, thus improving the temperature transition.

[0034] In various embodiments, at least one recycling pump is a centrifugal pump and / or is located upstream of the recycling heat exchanger. Having a centrifugal pump provides a particularly inexpensive and more reliable pump, as the centrifugal pump does not require any chamber to be sealed, and therefore any fouling that accumulates in the pump cannot be prevented by any seal. In particular, when operating near the minimum flow velocity, centrifugal pumps usually provide a relatively constant flow so that the flow velocity remains faster than the minimum flow velocity in a more reliable manner.

[0035] In various embodiments, the apparatus comprises at least one heating element configured to selectively heat at least one section of the apparatus. This makes it possible to maintain the temperature of individual parts while switching the flow of the fluid hydrocarbon or removing it from the flow of the fluid hydrocarbon. As a result, the material does not solidify in these parts.

[0036] In various embodiments, the apparatus comprises at least two recyclable heat exchangers, and the apparatus is configured to selectively pass fluid hydrocarbons through only one of the at least two recyclable heat exchangers.

[0037] In various embodiments, the apparatus includes at least one degassing section configured to reduce the proportion of hydrocarbons in the gas phase from the fluid hydrocarbons before they enter the recycle pump. The degassing section can help reduce the amount of gas in the fluid hydrocarbons in the recycle loop. Having less gas in the fluid hydrocarbons improves the function of the recycle pump, as it allows the recycle pump to primarily feed hydrocarbons in the liquid phase, thus enabling a greater load on the recycle pump. In various embodiments, the degassing section operates based on the difference in specific gravity between the hydrocarbons in the gas phase and the liquid phase. In various embodiments, the degassing section operates based on gravity or centrifugal force.

[0038] In various embodiments, the degassing section extends vertically and is configured to allow the fluid hydrocarbon to pass downward. In various embodiments, the degassing section is configured to establish a flow velocity slower than the flow velocity in the remainder of the recycle loop before the recycle pump.

[0039] In various embodiments, the degassing section is configured to establish a flow velocity of fluid hydrocarbons downward of less than 0.054 m / s, preferably less than 0.04 m / s, and more preferably less than 0.03 m / s.

[0040] In various embodiments, the apparatus comprises at least two degassing sections arranged parallel to each other.

[0041] In various embodiments, the apparatus includes a recycle density sensor configured to determine the density of the fluid hydrocarbon passing through to the recycle pump. The density is preferably determined by scintillator-based technology, such as Tracerco's Hyperion®.

[0042] In various embodiments, the apparatus includes a control element comprising a microprocessor and memory, the memory storing instructions to operate any of the recycle pump, recycle heat exchanger, separator vessel, carbon emission point, and / or back pressure control element when executed by the microprocessor. In various embodiments, the control element receives signals from at least one of the recycle pump, recycle heat exchanger, separator vessel, recycle density sensor, carbon emission density sensor, and / or back pressure control element so that the microprocessor processes and in particular controls any of the recycle pump, recycle heat exchanger, separator vessel, carbon emission point, and / or back pressure control element.

[0043] In various embodiments, the microprocessor is configured to compare densities indicated by a carbon emission density sensor and a recycling density sensor, and to operate the carbon emission point in accordance with the results of the density comparison.

[0044] In various embodiments, a method for the thermal decomposition of fluid hydrocarbons is - A step of supplying gaseous and fluid hydrocarbons at the thermal decomposition temperature through a heat exchanger, - A step of establishing a flow velocity of at least 1 m / s of a fluid hydrocarbon in at least one tube. Includes.

[0045] In various embodiments, the method for the thermal decomposition of fluid hydrocarbons is further, - The step of preparing the separator container, - A step of receiving gaseous and fluid hydrocarbons at the pyrolysis temperature from the heat exchanger at the recycling inlet of the separator container, - A step of releasing the gaseous material at the upper outlet of the separator container, - Steps include releasing the fluid hydrocarbon at the lower outlet of the separator container and The lower outlet includes a section that passes the fluid hydrocarbon to at least one recycling pump.

[0046] In another embodiment, the control element comprises a microprocessor and memory, the memory storing instructions that, when executed by the microprocessor, cause an apparatus for pyrolysis of fluid hydrocarbons to carry out a method for pyrolysis of fluid hydrocarbons.

[0047] In various embodiments, the heat exchanger exposes the fluid hydrocarbons to temperatures up to 50°C higher than the temperature of each fluid hydrocarbon, preferably up to 30°C higher than the temperature of each fluid hydrocarbon.

[0048] In some embodiments, the supply device 7 is positioned to fill the heating device 11 with a material containing long-chain hydrocarbons, such as the waste plastic discussed. In some embodiments, the supply device 7 includes an effector 8 for heating and / or feeding the material containing long-chain hydrocarbons. In some embodiments, the effector is a screw-type prism 8, preferably positioned to also heat the material for feeding the material containing long-chain hydrocarbons. In some embodiments, the screw-type prism 8 moves the material, and internal friction in the material heats and melts the material. In further embodiments, the supply device 7 includes a heating device such as an electric heater, or a heating device perfused with a heating medium such as a heat transfer oil. The supply device 7 carries the material containing long-chain hydrocarbons to the heating device 11.

[0049] The substantial portion of the solid particulate matter will be obtained from the pyrolysis reaction, which is the generation of char or coke particles common in pyrolysis. Other particulate matter may be present due to impurities in the initial plastic feedstream to the process, such as metal particles and other detritus, including organic matter. In the exemplary embodiment, four heating zones are shown. Each of heating zones 1, 2, 3, and 4 may be a tube of a heat exchanger, preferably a shell heat exchanger. Heating zones 1, 2, 3, and 4 provide a flow path for fluid hydrocarbons containing long-chain hydrocarbons. Heating zones 1, 2, 3, and 4 increase the exposure temperature continuously or gradually along the flow path. Heating is preferably carried out gradually so as to reduce or avoid char formation through excessive temperature differences.

[0050] The heating device 11 heats and melts the feed material of the plastic material, raising its temperature to the pyrolysis temperature. Within the context of this application, the pyrolysis temperature is, in particular, the minimum temperature for pyrolysis cracking of a substantial amount of fluid hydrocarbons. Cracking may begin in any of heating zones 1, 2, 3, or 4, with most of the cracking occurring in the heating zones preferably occurring in heating zone 4, which is the hottest heating zone of the four. The pyrolysis temperature may be 360°C or higher, more preferably 390°C or higher, preferably 395°C or higher, preferably 400°C or higher, and more preferably 410°C or higher. The pyrolysis temperature may be in the range of 360°C to 550°C, more preferably 390°C to 450°C.

[0051] The molten, partially thermally decomposed plastic material exits the heating zone 4 at the thermal decomposition temperature and enters the separator container 12 through the separator container inlet 14.

[0052] In the separator container 12, the incoming cracked gas and liquid are separated. The gas rises and exits into the distillation section, while the liquid falls to the bottom of the separator container 12. The heavy hydrocarbons return from the distillation section to the separator container 12.

[0053] The separator container 12 is associated with a recycling loop 26 provided to remove the liquid, partially pyrolyzed plastic material collected in the separator container 12. The recycling loop 26 comprises a recycling pump 27 and a recycling heat exchanger 28. The recycling pump 27 is configured to send the fluid hydrocarbon from the separator container 12 through the recycling heat exchanger 28. The recycling heat exchanger 28 reheats the sent fluid hydrocarbon to its pyrolysis temperature. The recycling loop 26 then returns the fluid hydrocarbon to the separator container 12. In the illustrated case in Figure 1, the fluid hydrocarbon returns to the separator container 12 together with the fresh supply fluid hydrocarbon. In an alternative embodiment, the fluid hydrocarbon returns to the separator container 12 separately from the fresh supply fluid hydrocarbon.

[0054] This recycling loop 26 extends the residence time for long-chain hydrocarbons at the pyrolysis temperature so that they are subjected to further pyrolysis and breakdown into shorter-chain hydrocarbons, and eventually exit through the distillation section.

[0055] The recycling loop 26 brings reheating and heat reintroduction to the separator container 12, so that the separator container 12 remains at the thermal decomposition temperature. The heat is carried into the separator container 12 by the incoming reheating flow of material provided by the recycling loop 26.

[0056] In the illustrated preferred embodiment, the separator container 12 is non-heated, and the term “non-heated” means that the separator container 12 is not heated by any source other than the heat carried by the incoming heated material, for example, heated material enters the internal volume of the separator container 12 from a heating device such as heating device 11 or another heating device which may be presented in the recycling loop 26.

[0057] As can be found in several conventional attempts, it has been found to be useful to avoid providing heating means on or inside the separator vessel 12. This can help reduce char formation in the separator vessel 12 and reduce or avoid the requirements for special stirring means. For example, conventional attempts have found that internal heaters, such as heating coils, can cause fouling of the material being pyrolyzed on the surface of the heating element. This fouling can represent a loss of product and may collect on the heating element, requiring downtime for cleaning and maintenance. The same is true for cracking reactor type vessels, where the vessel walls are heated to bring the processed material to or maintain the pyrolysis temperature. Char formation can occur on the inner surface of the cracking reactor, resulting in the need for complex mixing, cleaning, and downtime. Nevertheless, the use of direct heating of the separator vessel, for example, via a jacket or internal heating exchanger or heating coil, is not excluded from use in some embodiments or aspects of the present invention and may be used to supply all or part of the thermal requirements to the pyrolysis zone(s).

[0058] In the exemplified preferred embodiments, the separator vessel 12 is not provided with a stirrer or auger. While not strictly theoretical, providing an auger or similar stirring device to agitate the liquid in the separator vessel is considered disadvantageous because it introduces complexity; reduces efficiency and requires maintenance by forming a surface area where carbon / char can accumulate; and may interfere with the flow pattern imparted by the injection or material. However, a stirrer within the separator vessel 12 may be provided, or is not excluded from certain embodiments and aspects, so that it may be useful in improving mixing within the separator vessel 12 at an optional cost.

[0059] By the time it enters the separator container 12 via the inlet 14, the fluid hydrocarbon is at its thermal decomposition temperature and is therefore undergoing thermal decomposition. Cracking of the plastic material results in the generation of a wide range of substances with a wide range of boiling points. The fluid hydrocarbon leaving the heating device 11 and entering the separator container 12 via the inlet 14 contains at least both gaseous and liquid components, the liquid component containing, and possibly substantially consisting of, at least partially cracked fluid hydrocarbons. The liquid component may also contain molten, uncracking plastic material. The fluid hydrocarbon leaving the heating device 11 and entering the separator container 12 via the inlet 14 may further contain silt and other solid detritus, such as sand, aluminum, or other metallic particles.

[0060] The illustrated separator container 12 is elongated and positioned substantially vertically. Non-vertical arrangements, such as inclined or horizontal, are also possible. The pyrolyzed gaseous material rises within the separator container 12, while the (partially) pyrolyzed liquid material descends under its own weight. In this way, the gaseous and liquid materials diffuse and thus separate within the separator container 12. In various embodiments, the separator container 12 has a cylindrical shape with a lower conical portion. The lower conical portion reaches its apex at its lowest point, the carbon release point 129.

[0061] In various embodiments, the separator vessel 12 includes an upper outlet 132 and a line 6 to a distillation section. The gaseous hydrocarbon material rising within the separator vessel 12 is released through the upper outlet 132 and passes through line 6 to the distillation section. The distillation section is separate from the separator vessel 12 and is located below the separator vessel 12. The distillation section is in fluid communication with the separator vessel 12 via line 6.

[0062] The distillation section is configured to remove heavy fractions from the outgoing gas (reducing relatively high-point fractions) before the gas passes further into the complete distillation or condenser section of the apparatus and process. In the distillation section, the gas is cooled. As the gas cools, heavier fractions can be condensed and collected.

[0063] The downstream distillation section can be designed according to industrial standards known to those skilled in the art. The gas can be fractionated into a gaseous fraction and a liquid fraction. The liquid fraction may be removed as an intermediate distillate, and the gaseous fraction may be removed in the distillation unit as a light boiler. Hydrocarbon products from the distillation unit may include butane, propane, kerosene, diesel, fuel oil; light distillates, e.g., LPG, gasoline, naphtha, or mixtures thereof; intermediate distillates, e.g., kerosene, jet fuel, diesel, or mixtures thereof; heavy distillates and residues, e.g., fuel oil, lubricating oil, paraffin, wax, asphalt, or mixtures thereof; or any mixture thereof. The hydrocarbon products may be saturated or unsaturated, linear or cyclic, or aromatic. Further products may include non-condensing gases, including methane, ethane, ethene, and / or other small molecules. The products may be a source of feed material for steam crackers in the manufacture of plastics.

[0064] Figure 2 shows a schematic diagram of the separation vessel 12 equipped with a recycle loop 26. The recycle loop 26 is a source of thermal energy to the separator vessel 12, preferably the primary source of thermal energy to the separator vessel 12, and therefore compensates for heat loss due to gas released through the distillation section.

[0065] For example, the liquid 140 in the lower part of the separator container 12, which includes molten plastic and partially pyrolyzed hydrocarbons, is pumped to the recycling heat exchanger 28 with the help of a recycling pump 27. In various embodiments, the recycling heat exchanger 28 is a shell and tubular heat exchanger, where the fluid hydrocarbon flows through the tubulars and the heating medium flows through the shell and tubulars, transferring heat from the heating medium to the fluid hydrocarbon. The recycling heat exchanger 28 (re)heats the liquid to a temperature higher than the temperature of the liquid in the separator container 12. For example, about 410°C to about 550°C, more preferably about 410°C to about 500°C, and even more preferably about 410°C to about 450°C.

[0066] Since pyrolysis occurs at these temperatures, the liquid flow pumped out will generate pyrolysis gases and will contain some of these gases. To reduce the cavitation effect in the recycle pump 27, it is preferable that the recycle pump 27 be located upstream of the recycle heat exchanger 28, and therefore the recycle pump 27 is presented mainly with the liquid phase. The (re)heated fluid passes to the original separator container 12, carrying thermal energy through its liquid and heating the inside of the separator container 12.

[0067] Due to thermal decomposition, carbon solids form within the heat exchanger 28 and tend to settle, clogging the recycle heat exchanger 28. In various embodiments, the fluid within the recycle heat exchanger 28 has a minimum velocity to maintain the solid particles in suspension and prevent settling. Maintaining the solid particles in suspension reduces surface fouling of the tubes of the recycle heat exchanger 28 by carbon or char. The minimum velocity is about 1 m / s, preferably about 2 m / s, at the tube inlet of the recycle heat exchanger 28. That is, the recycle pump 27 and the recycle heat exchanger 28 are configured such that the minimum velocity at the tube inlet of the recycle heat exchanger 28 is about 1 m / s, preferably about 2 m / s. The velocity at the outlet of the heat exchanger 28 may be higher due to gas formation, which increases volume and pressure.

[0068] The liquid-gas mixture is then guided by the recycle loop 26 to be injected tangentially at high speed (e.g., about 5 m / s, more preferably about 8 m / s, and most preferably about 10 m / s) into the cracking reactor. Tangential injection can advantageously help provide a swirling or cyclone flow pattern of the fluid within the separation vessel 12. The liquid, gas mixture is preferably injected below the liquid level 141. This can help generate the desired flow pattern in the gas / liquid zone in the separator vessel 12 and / or reduce or prevent blockage at the injection point.

[0069] In various embodiments, the recycle loop 26 is configured to pyrolytically crack at least a portion of the fluid hydrocarbons passing through it. The temperature range required for pyrolytic cracking depends on the composition of the fluid hydrocarbons in the recycle loop 26. Some fluid hydrocarbons typically crack at lower temperatures, for example, above 360°C, while others typically crack only at higher temperatures, close to or above 550°C. Furthermore, some fluid hydrocarbons typically crack at temperatures between 360°C and 550°C. To crack at least a portion of the fluid hydrocarbons, the recycle heat exchanger 28 is configured to transfer thermal energy to the fluid hydrocarbons passing through it. In various embodiments, the thermal energy is estimated to raise the temperature of the fluid hydrocarbons above their respective pyrolysis temperatures. The thermal energy is estimated to raise the temperature of the fluid hydrocarbons to 360°C or higher, more preferably 390°C or higher, preferably 395°C or higher, preferably 400°C or higher, and more preferably 410°C or higher. The thermal decomposition temperature may be primarily in the range of 360°C to 550°C, more preferably in the range of 390°C to 450°C. The required thermal energy further depends on the temperature of the fluid hydrocarbon entering the recycle loop 26. In various embodiments, the temperature and composition of the material entering the recycle loop 26 depend on the occupancy rate of the fluid hydrocarbon and cracked gas in the separator vessel 12. Primarily the fluid hydrocarbon will pass through the recycle loop 26. The cracked gas will mainly evaporate in the separator vessel 12 and exit through the distillation section. The evaporation of the cracked gas removes some of the thermal energy of the fluid hydrocarbon. The recycle loop 26 provides thermal energy to the fluid hydrocarbon, at least partially compensating for the thermal energy removed by the evaporation of the cracked gas.

[0070] In various embodiments, the recycle heat exchanger 28 is configured to transfer the thermal energy required for the fluid hydrocarbons to reach their respective pyrolysis cracking temperatures. In various embodiments, when the minimum speed is about 1 m / s as specified above, the recycle heat exchanger 28 is configured to provide increased exposure. This can be done primarily by increasing the temperature of the heating medium for the recycle heat exchanger 28. In various embodiments, increased exposure is achieved by extending the time the fluid hydrocarbons pass through the recycle heat exchanger 28, in particular by providing extended flow paths through the recycle heat exchanger 28, and thus extending the residence time of the fluid hydrocarbons within the recycle heat exchanger 28. This makes it possible to expose the fluid hydrocarbons within the recycle heat exchanger 28 to a specific temperature above the temperature of each fluid hydrocarbon, for example, up to 50°C higher than the temperature of each fluid hydrocarbon, preferably up to 30°C higher than the temperature of each fluid hydrocarbon. It was found that limiting the exposure temperature to 50°C or below reduces or prevents the accumulation of fouling and clogging in the recycled heat exchanger 28.

[0071] In various embodiments, increased exposure is achieved by providing at least a minimum heat exchange surface area for contact with the fluid hydrocarbon as it passes through the recycle heat exchanger 28. In further embodiments, the minimum heat exchange surface is provided by extending the length of the passages for the fluid hydrocarbon within the recycle heat exchanger 28. Alternatively, as an addition to the increased passage length, the number of tubes passing the fluid hydrocarbon through the recycle heat exchanger 28 in parallel is increased.

[0072] While the composition of the feed material for the plastic material entering the heating device 11 can be varied, it was found that at least some of the fluid hydrocarbons that crack most easily will evaporate before entering the recycling loop 26, so that the fluid hydrocarbons entering the recycling heat exchanger 28 are not as diverse as the initial feed material. Furthermore, the minimum heat exchange surface depends particularly on the thermal energy transferred through the interior. The thermal energy is primarily a function of the throughput of the fluid hydrocarbons and the temperature rise determined with respect to the fluid hydrocarbons. The predetermined thermal energy transferred does not depend so much on the pyrolysis temperature of the fluid hydrocarbons. This allows for the dimensioning of the minimum heat exchange surface of the recycling heat exchanger 28 as a function of the predetermined throughput of the fluid hydrocarbons passing through the recycling heat exchanger 28.

[0073] In various embodiments, the throughput of fluid hydrocarbons through the recycle heat exchanger 28 is determined by a predetermined throughput of fresh supply fluid hydrocarbons to the separator container 12. In this context, fresh supply fluid hydrocarbons are fluid hydrocarbons that are entering the separator container 12 for the first time and have not previously passed through the recycle loop 26. In various embodiments, fluid hydrocarbons also include gases. In various embodiments, the throughput of fluid hydrocarbons through the recycle heat exchanger 28 is at least 8 times the throughput of fresh supply fluid hydrocarbons to the separator container 12 in terms of volume, and preferably between 10 and 20 times the throughput of fresh supply fluid hydrocarbons to the separator container 12 in terms of weight. In various embodiments, the minimum heat exchange surface area is determined based on the weight of fresh supply fluid hydrocarbons, at least 80 m³ per predetermined throughput of 3000 kg / hour of fresh supply fluid hydrocarbons. 2 That is the case.

[0074] In various embodiments for regulating at least one of the flow velocity or temperature of the fluid hydrocarbon in the recycle heat exchanger 28, the recycle loop comprises at least one of monitoring means configured to acquire values ​​indicating the flow velocity and / or temperature of the fluid hydrocarbon, and control means configured to adjust the flow velocity by adjusting the recycle pump 27 and / or adjust the temperature of the fluid hydrocarbon in the recycle heat exchanger 28. In various embodiments, the monitoring means and / or control means comprises electronic means configured to output commands for the control means to process and / or adjust the acquired flow velocity and / or temperature accordingly. In various embodiments, the electronic means is a processor or electronic controller storing corresponding computer code.

[0075] Figure 3 shows the separator container 12 and the recycle loop 26 with further features. The liquid 140 in the lower portion of the separator container 12 is drawn out of the separator container 12 through one or more outlets. In the exemplary embodiment, two outlets are shown: an internal, preferably substantially central, liquid outlet 128 and a side liquid outlet 127 located in the hollow body of the separator container. The liquid outlets 128 and 127 may be used individually or together.

[0076] As described above, various embodiments are configured to generate swirling flow patterns. The centrifugal force thus induced separates various hydrocarbons according to their respective densities with respect to mass per unit volume. While not strictly theoretical, the volume of long-chain hydrocarbons tends to have a higher density than that of shorter or branched hydrocarbons. Therefore, long-chain hydrocarbons tend to swirl more outward than other hydrocarbons such as shorter or branched hydrocarbons. By having a liquid outlet on the side of the separator container 12, such as a side liquid outlet 127, it is possible to preferentially deliver hydrocarbons with long, straight chains into the recycle loop. These hydrocarbons with long, straight chains also, unintentionally, crack more easily than shorter or branched hydrocarbons. Therefore, some embodiments with a side liquid outlet 127 make it possible to more easily and preferentially deliver cracking hydrocarbons to the recycle heat exchanger 28. In some embodiments, this may be preferable when the recycle heat exchanger 28 has a lower temperature, for example, during the warm-up phase.

[0077] In various embodiments, centrifugal force also helps separate solid particles and sediment from the center of the liquid 140. Therefore, positioning the central liquid outlet 128 helps minimize the amount of solid particles and sediment drawn out through the central liquid outlet 128. This helps avoid or reduce fouling and blockage of the recycle loop 26, particularly the recycle pump 27 and the recycle heat exchanger 28.

[0078] In the exemplary embodiments, the separator container 12 and the recycle pump 27 are configured to produce a height difference H between the recycle pump 27 and the liquid level in the separator container 12. The height difference corresponds to at least the required net suction head (NPSH) of the recycle pump 27, i.e., the head value required to prevent cavitation by the fluid hydrocarbons in the recycle pump 27. In various embodiments, the height difference H is at least 7 meters, and more preferably at least 10 meters.

[0079] During operation, the separator container 12 is filled with gaseous and fluid hydrocarbons at substantially pyrolysis temperature. The fluid hydrocarbons 140 fill the lower conical and lower cylindrical portions to a level above the side liquid outlets 127 and / or the central liquid outlet 128. The upper portion of the separator container 12 is filled with gaseous material. The recycle pump 27 draws the fluid hydrocarbons from the separator container 12 through the side liquid outlets 127 and / or the central liquid outlet 128. The recycle pump 27 sends the fluid hydrocarbons through the recycle heat exchanger 28 so that the fluid hydrocarbons reach a minimum velocity at the inlet of the heat exchanger 28. The minimum velocity is adjusted to maintain solid particles in suspension and to prevent them from settling. In various embodiments, the minimum velocity is at least 1 m / s. In further embodiments, the velocity of the fluid hydrocarbons is at least 2 m / s, preferably at least 5 m / s.

[0080] As the fluid hydrocarbons pass through the recycle heat exchanger 28, some of them crack into shorter chains. Since shorter-chain hydrocarbons typically have lower boiling points, some of the shorter-chain hydrocarbons turn into the gas phase and occupy more volume, thus increasing the rate of the fluid hydrocarbons within the recycle heat exchanger 28.

[0081] In various embodiments, the recycle loop 26 includes a back pressure control element. In various embodiments, the back pressure control element is located downstream of the recycle heat exchanger 28. The recycle pump 27 and the back pressure control element are configured to maintain fluid hydrocarbons in at least one recycle heat exchanger 28 at an increased pressure to suppress the hydrocarbons from changing to the gas phase. In various embodiments, the increased pressure is at least 2 bar, preferably at least 5 bar, and more preferably at least 15 bar. The increased pressure in the recycle heat exchanger 28 suppresses bubble formation and provides more surface area for the fluid hydrocarbons to receive heat from the heat exchange surface (on the other surface heated by the heating medium). Gases have inferior heat exchange properties compared to liquids. In some embodiments, the higher pressure in the recycle heat exchanger 28 limits the velocity in the recycle heat exchanger 28 so as to avoid noise problems or excessive erosion.

[0082] The recycle loop 26 further includes a recycle inlet 25. The (re)heated fluid returns to the original separator container 12 through the recycle inlet 25, carrying thermal energy with it and heating the inside of the separator container 12. In various embodiments, the recycle inlet is located separately from the separator container inlet 14. In further embodiments, the recycle inlet 25 is disemboguered from the separator container inlet 14 so as to mix the fresh feed fluid hydrocarbons and the recycled feed fluid hydrocarbons and enter the separator container 12 together.

[0083] For example, in various embodiments, the fluid hydrocarbons have temperatures higher than 380°C. In various embodiments, the recycle heat exchanger 28 is configured to expose the fluid hydrocarbons within the recycle heat exchanger 28 to an exposure temperature up to 50°C higher than the temperature of each fluid hydrocarbon. In various embodiments, the fluid hydrocarbons have temperatures higher than 400°C, and the recycle heat exchanger 28 exposes the fluid hydrocarbons within the recycle heat exchanger 28 to an exposure temperature up to 30°C higher than the temperature of each fluid hydrocarbon. It has been found that by further limiting the exposure temperature to 30°C or less for fluid hydrocarbons with temperatures higher than 400°C, the accumulation of fouling and clogging can be reduced or prevented.

[0084] Therefore, the temperature difference between the fluid hydrocarbon temperature and the exposure temperature is fixed at 50°C or less. Since the temperature difference is fixed within this range, the thermal energy transferred to the fluid hydrocarbon is also within a limited range. Thus, the heat exchange surface of the recycle heat exchanger 28 can remain the same with respect to various exposure temperatures. The size of the heat exchange surface of the recycle heat exchanger 28 is particularly due to a predetermined flow rate with respect to the fluid hydrocarbon in the recycle heat exchanger and / or with respect to the volume of fresh supply fluid hydrocarbon. In various embodiments, the heat exchange surface area is at least 80 m² per predetermined throughput of fresh supply fluid hydrocarbon of 3000 kg / hour. 2 In various embodiments, this surface area can result in an exposure temperature and a flow velocity of at least 1 m / s, preferably 2 m / s, and thus operates by reducing the generation and / or sedimentation of soot, char, and / or other solids within the recycling loop 26.

[0085] Figure 4 shows one embodiment of the separator container 12 and the recycle loop 26 having further features. In Figure 4, the recycle loop 26 has first and second recycle loop branches 26a, 26b. The first recycle loop branch 26a extends from the central liquid outlet 128. The first recycle loop branch 26a comprises a first recycle pump 271 and a first recycle heat exchanger 281. In various embodiments, the first recycle loop branch 26a comprises at least one of a first cooling member 261a, a first strainer 263a, and a first flow meter 265a. In various embodiments, the first recycle loop branch 26a comprises at least one first recycle piping configured to transmit fluid hydrocarbons along the first recycle loop branch 26a. The first recycle piping establishes a connection between the central liquid outlet 128, the first recycle pump 271, and the first heat exchanger 281. In some embodiments, the first recycling piping includes insulation configured to reduce the dissipation of thermal energy from the fluid hydrocarbons into the environment. The insulation is specifically formed around the piping and extends essentially along the entirety of the first recycling piping.

[0086] The first cooling member 261a is located upstream of the first recycle pump 271 and is configured to lower the temperature of the fluid hydrocarbon by at least 1°C, preferably at least 5°C, before it enters the first recycle pump. In various embodiments, this lowered temperature can reduce the vapor pressure of the fluid hydrocarbon, thus reducing the tendency for cavitation in the operating first recycle pump 271. Thus, the lowered temperature of the fluid hydrocarbon reduces the NPSH, and therefore reduces the height difference H between the first recycle pump 271 and the liquid level in the separator container 12. In various embodiments, the first cooling member 261a is formed by a heat exchanger structure configured to transfer heat from the fluid hydrocarbon to a cooling medium. In various embodiments, the first cooling member is formed by structural measures that allow heat to be dissipated into the environment by the fluid hydrocarbon. In various embodiments, the first cooling member 261a is formed by removing at least a portion of the insulation along a section of the first recycle piping. In further embodiments, the first cooling member 261a comprises a cooling duct configured to circulate a cooling fluid, receive thermal energy from the fluid hydrocarbon in the first recycling pipe, and distribute the thermal energy to the cooling fluid in the cooling duct. In various embodiments, the recycling pipe in the first cooling member 261 is provided with fins inside the pipe to increase the surface area for cooling the fluid hydrocarbon.

[0087] In various embodiments, the first strainer 263a is located along the first recycle loop branch 26a upstream of the first heat exchanger 281. In various embodiments, the first strainer is located along the first recycle loop branch 26a upstream of the first recycle pump 271. The first strainer 263a is configured to protect the first recycle pump 271 and / or the first heat exchanger 281 by reducing the amount of solids suspended in the fluid hydrocarbon before it reaches the first recycle pump 271 and / or the first heat exchanger 281. In various embodiments, the first strainer 263a includes a separator that removes solids from the fluid hydrocarbon passing through the first recycle pump 271 and / or the first heat exchanger 281. In various embodiments, the first strainer 263a includes a filter that removes solids from the fluid hydrocarbon. In various embodiments, the first strainer 263a includes a sieve or mesh that removes solids from the fluid hydrocarbon. In various embodiments, the first strainer 263a is configured to allow for frequent or continuous removal of solids to be removed from the fluid hydrocarbon.

[0088] In various embodiments, the first recycle pump 271 is configured to set the pressure of the fluid hydrocarbon in the first heat exchanger 281 to at least 2 bar, preferably at least 5 bar, and more preferably at least 15 bar. The increased pressure in the first heat exchanger 281 suppresses bubbles, leaving more space for the liquid to exchange heat with the heat exchanger surface (on the other surface heated by the heating medium). Since gases have poorer heat exchange properties compared to liquids, the increased occupancy of liquid improves heat exchange. The higher pressure in the first heat exchanger 281 also prevents the velocity in the pipes from exceeding levels that would cause noise problems or excessive erosion in the first heat exchanger 281.

[0089] In various embodiments, the first recycle pump 271 is configured as a centrifugal pump. The centrifugal pump is configured to transport fluid hydrocarbons by converting the rotational kinetic energy of the fluid hydrocarbon flow into hydrodynamic energy. The centrifugal pump comprises an impeller and a housing. The impeller is configured to rotate the fluid hydrocarbon radially outward, and thus accelerate it. The housing is configured to house the impeller and guide the fluid hydrocarbon along the impeller and toward the outlet. The impeller increases the pressure and / or flow velocity of the fluid hydrocarbon. In various embodiments, the first recycle pump 271 comprises at least two centrifugal pump stages, each stage comprising an impeller that steps up the pressure and / or flow velocity of the fluid hydrocarbon. In various embodiments, the centrifugal pump comprises four stages. In various embodiments, the pump stages vary the compression ratio by having the highest compression ratio in the first stage and the lowest compression ratio in the final stage. Thus, it becomes possible to reach higher pressures with the output of the centrifugal pump.

[0090] In various embodiments, the first recycling pump 271 is a positive displacement pump such as a lobe pump.

[0091] In various embodiments, the first heat exchanger 281 is a shell and tubular heat exchanger. In various embodiments, the first heat exchanger 281 corresponds to the recycle heat exchanger 28 discussed further above. In various embodiments, the first recycle pump 271 and the first heat exchanger 281 are configured such that the fluid hydrocarbon flow rate is at least about 1 m / s, preferably at least about 2 m / s, at the tube inlet of the first heat exchanger 281. The size of the heat exchange surface of the first heat exchanger 281 is due in part to a predetermined flow rate with respect to the fluid hydrocarbon in the first heat exchanger 281 and / or with respect to the volume of fresh feed fluid hydrocarbon. In various embodiments, the heat exchange surface area is at least 80 m² per predetermined throughput of fresh feed fluid hydrocarbon of 3000 kg / hour. 2 That is the case.

[0092] In various embodiments, the recycle loop 26 allows the fluid hydrocarbon to pass through the heat exchanger at least twice. In various embodiments, the recycle loop 26 is configured to prevent fouling of sections of the recycle piping connecting the heat exchanger. In particular, the throughput of the fluid hydrocarbon in the recycle piping connecting the heat exchanger is adjusted to maintain solid particles in suspension and prevent sedimentation of solid particles.

[0093] In various embodiments, the first flow meter 265a is configured to evaluate the throughput of a fluid hydrocarbon through the first heat exchanger 281. The evaluated throughput can provide an index of the flow velocity in the first heat exchanger 281, particularly at its inlet. In various embodiments, the evaluated throughput of the fluid hydrocarbon passes through to control the flow velocity in the first heat exchanger 281. In various embodiments, the first recycle loop 26a includes a first control means configured to receive a value indicating the throughput evaluated by the first flow meter 265a and to output adjustment commands to the first recycle pump 271 to adjust the flow velocity in the first heat exchanger 281, particularly at its inlet. In various embodiments, the first flow meter 265a and / or the control means include electronic means configured to process the index of the flow velocity and / or to output commands relating to the first recycle pump 271 to adjust accordingly. In various embodiments, the electronic means is a processor or electronic controller storing corresponding computer code.

[0094] The second recycle loop branch 26b extends from the side liquid outlet 127. The second recycle loop branch 26b comprises a second recycle pump 272 and a second recycle heat exchanger 282. In various embodiments, the second recycle loop branch 26b comprises at least one of a second cooling member 261b, a second strainer 263b, and a second flow meter 265b. In various embodiments, the second recycle loop branch 26b comprises at least one second recycle piping configured to transmit fluid hydrocarbons along the second recycle loop branch 26b. The second recycle piping establishes a connection between the side liquid outlet 127, the second recycle pump 272, and the second heat exchanger 282. In some embodiments, the second recycle piping comprises insulation configured to reduce the dissipation of thermal energy from the fluid hydrocarbons to the environment. The insulation is specifically formed around the piping and extends essentially along the entire second recycle piping.

[0095] The second cooling member 261b is located upstream of the second recycle pump 272 and is configured to lower the temperature of the fluid hydrocarbon by at least 1°C, preferably at least 5°C, before it enters the second recycle pump 272. In various embodiments, this lowered temperature can reduce the vapor pressure of the fluid hydrocarbon and thus reduce the tendency for cavitation in the operating second recycle pump 272. Thus, the lowered temperature of the fluid hydrocarbon reduces the NPSH and thus reduces the height difference H between the second recycle pump 272 and the liquid level in the separator container 12. In various embodiments, the second cooling member 261b is formed by a heat exchanger structure configured to transfer heat from the fluid hydrocarbon to a cooling medium. In various embodiments, the second cooling member is formed by structural measures that allow heat to dissipate into the environment in the fluid hydrocarbon. In various embodiments, the second cooling member 261b is formed by removing at least a portion of the insulation along a section of the second recycle piping. In further embodiments, the second cooling member 261b comprises a cooling duct configured to receive thermal energy from the fluid hydrocarbon in the second recycling pipe and to distribute the thermal energy to the cooling fluid in the cooling duct so that the cooling fluid circulates. In various embodiments, the recycling pipe in the second cooling member 261b is provided with fins inside the pipe to increase the surface area for cooling the fluid hydrocarbon.

[0096] In various embodiments, the second strainer 263b is located upstream of the second heat exchanger 282 along the second recycle loop branch 26b. In various embodiments, the second strainer 263b is located upstream of the second recycle pump 272 along the second recycle loop branch 26b. The second strainer 263b is configured to protect the second recycle pump 272 and / or the second heat exchanger 282 by reducing the amount of suspended solids in the fluid hydrocarbon before it reaches the second recycle pump 272 and / or the second heat exchanger 282. In various embodiments, the second strainer 263b includes a separator that removes solids from the fluid hydrocarbon passing to the second recycle pump 272 and / or the second heat exchanger 282. In various embodiments, the second strainer 263b includes a filter that removes solids from the fluid hydrocarbon. In various embodiments, the second strainer 263b includes a sieve or mesh for removing solids from the fluid hydrocarbon. In various embodiments, the second strainer 263a is configured to allow for frequent or continuous removal of solids to be removed from the fluid hydrocarbon.

[0097] In various embodiments, the second recycle pump 272 is configured to set the pressure of the fluid hydrocarbon in the second heat exchanger 282 to at least 2 bar, preferably at least 5 bar, and more preferably at least 15 bar. The increased pressure in the second heat exchanger 281 suppresses bubbles, leaving more space for the liquid to exchange heat with the heat exchanger surface (on the other surface heated by the heating medium). Since gases have poorer heat exchange properties compared to liquids, the increased occupancy of liquid improves heat exchange. The higher pressure in the second heat exchanger 282 also prevents the velocity in the pipes from exceeding levels that would cause noise problems or excessive erosion in the second heat exchanger 282.

[0098] In various embodiments, the second recycle pump 272 is configured as a centrifugal pump. The centrifugal pump is configured to transport fluid hydrocarbons by converting the rotational kinetic energy of the fluid hydrocarbon flow into hydrodynamic energy. The centrifugal pump comprises an impeller and a housing. The impeller is configured to rotate the fluid hydrocarbon radially outward, and thus accelerate it. The housing is configured to house the impeller and guide the fluid hydrocarbon along the impeller and toward the outlet. The impeller increases the pressure and / or velocity of the fluid hydrocarbon. In various embodiments, the second recycle pump 272 comprises at least two centrifugal pump stages, each stage comprising an impeller that steps up the pressure and / or velocity of the fluid hydrocarbon. In various embodiments, the centrifugal pump comprises four stages. In various embodiments, the pump stages vary the compression ratio by having the highest compression ratio in the first stage and the lowest compression ratio in the final stage. In various embodiments, the second recycle pump 272 is configured to provide a compression difference with respect to the first recycle pump 271.

[0099] In various embodiments, the second recycling pump 272 is a positive displacement pump such as a lobe pump.

[0100] In various embodiments, the second heat exchanger 282 is a shell and tubular heat exchanger. In various embodiments, the second heat exchanger 282 corresponds to the recycle heat exchanger 28 discussed further above. In various embodiments, the second recycle pump 272 and the second heat exchanger 282 are configured such that the fluid hydrocarbon flow rate is at least about 1 m / s, preferably at least about 2 m / s, at the tube inlet of the second heat exchanger 282. The size of the heat exchange surface of the second heat exchanger 282 is particularly due to a predetermined flow rate with respect to the fluid hydrocarbon of the second heat exchanger 282 and / or with respect to the volume of fresh supply fluid hydrocarbon. In various embodiments, the heat exchange surface area is at least 80 m² per predetermined throughput of fresh supply fluid hydrocarbon of 3000 kg / hour. 2 That is the case.

[0101] In various embodiments, the second flow meter 265b is configured to evaluate the throughput of a fluid hydrocarbon through the second heat exchanger 282. The evaluated throughput can provide an index of the flow velocity in the second heat exchanger 282, particularly at its inlet. In various embodiments, the evaluated throughput of the fluid hydrocarbon passes through to control the flow velocity in the second heat exchanger 282. In various embodiments, the second recycle loop 26b includes a second control means configured to receive a value indicating the throughput evaluated by the second flow meter 265b and to output adjustment commands to the second recycle pump 272 to adjust the flow velocity in the second heat exchanger 282, particularly at its inlet. In various embodiments, the second flow meter 265b and / or the control means include electronic means configured to process the index of the flow velocity and / or to output commands relating to the second recycle pump 272 and adjust accordingly. In various embodiments, the electronic means is a processor or electronic controller storing corresponding computer code.

[0102] In various embodiments, the first and / or second centrifugal pumps and the back pressure control element 290 control the amount of fluid hydrocarbon flow through the first and / or second recycle heat exchangers 281, 282. In embodiments where positive displacement pumps are provided as the first and / or second recycle pumps, the back pressure valve 290 controls the pressure and the positive displacement pumps control the flow velocity.

[0103] In various embodiments, the first and second recycle loop branches 26a, 26b each comprise first and second shut-off valves 268a, 268b, and first to third interconnections 262, 264, 266. The first and second shut-off valves 268a, 268b and the first to third interconnections 262, 264, 266 are configured to be selectively closed. In various embodiments, the first and second recycle loop branches 26a, 26b are configured to bypass at least one of the first and second cooling members 261a, 261b, first and second recycle pumps 271, 272, first and second flow meters 265a, 265b, and first and second heat exchangers 281, 282 by selectively closing the first to third interconnections 262, 264, 266 and the first and second shut-off valves 268a, 268b. In various embodiments, the first interconnection 262 is configured to connect the first and second recycling pipes in communication after the first and second cooling members 261a, 261b and before the first and second strainers 263a, 263b. In various embodiments, the second interconnection 264 is configured to connect the first and second recycling pipes in communication after the first and second recycling pumps 271, 272 and before the first and second flow meters 265a, 265b. In various embodiments, the third interconnection 266 is configured to connect the first and second recycling pipes in communication after the first and second flow meters 265a, 265b and before the first and second heat exchangers 281, 282. In various embodiments, the first and second shut-off valves 268a and 268b are configured to open alternately and to communicate with the first and second heat exchangers 281 and 282, and to reach the back pressure control element 290, and thus the separator container inlet 14.

[0104] The first and second recycle loop branches 26a, 26b, having first and second shut-off valves 268a, 268b and first to third interconnections 262, 264, 266 as specified above, allow for the disconnection of at least one of the first and second cooling members 261a, 261b, the first and second recycle pumps 271, 272, the first and second flow meters 265a, 265b, and the first and second heat exchangers 281, 282, enabling maintenance of each structure without stopping the recycle loop 26, and consequently enabling an apparatus with the entire separator container 12. This helps to reduce the downtime of the separator container 12.

[0105] In further embodiments, parts of the structure in the first and second recycle loop branches 26a, 26b are configured to operate in parallel. For example, the first and second recycle pumps 271, 272 operate in parallel to supply fluid hydrocarbons to at least one of the first and second heat exchangers 281, 282. More specifically, in various embodiments, the recycle loop 26 is configured to operate one of the first and second recycle pumps 271, 272 at full capacity while the other of the first and second recycle pumps 271, 272 is switched off. In various embodiments, each of the first and second recycle loop branches 26a, 26b includes a valve configured to be closed and to prevent backflow through the respective switched-off recycle pumps 271, 272. In various embodiments, the recycle loop 26 is configured to operate both the first and second recycle pumps 271, 272 at equal capacity in such a manner that the fluid hydrocarbon flow velocity at at least one inlet of the first and second heat exchangers 281, 282 is at least about 1 m / s, preferably at least about 2 m / s.

[0106] In various embodiments, the recycle loop 26 comprises at least one valve configured to selectively close at least one of the first and second cooling members 261a, 261b, the first and second strainers 263a, 263b, the first and second recycle pumps 271, 272, the first and second flow meters 265a, 265b, and the first and second heat exchangers 281, 282, and thus to isolate it from the rest of the recycle loop 26.

[0107] In various embodiments, each of the first and second cooling members 261a, 261b, the first and second recycle pumps 271, 272, the first and second flow meters 265a, 265b, and the first and second heat exchangers 281, 282, as well as the first and second recycle loop branches 26a, 26b, the first and second shut-off valves 268a, 268b, and the first to third interconnections 262, 264, 266, is equipped with heating means capable of maintaining the containment of fluid hydrocarbons in a liquid state inside.

[0108] Figure 5 shows the separator container 12 and the recycle loop 26 with further features. As shown in Figure 3, the liquid 140 in the lower portion of the separator container 12 is drawn out of the separator container 12 through one or more outlets. In the embodiments of Figures 3-5, two outlets are shown: an internal, preferably substantially central, liquid outlet 128 and a side liquid outlet 127 located within the hollow body of the separator container. The liquid outlets 128 and 127 may be used individually or together.

[0109] In various embodiments, as specifically shown in Figure 5, the recycle loop 26 includes a degassing section 151. The degassing section 151 is configured to remove the fluid in the gas phase from the liquid after it enters the recycle loop 26, and in particular before the recycle pump 27.

[0110] As described above, various embodiments are configured to generate a swirling flow pattern within the separator container 12. The centrifugal force thus induced separates various hydrocarbons, and in particular supports the sedimentation of carbon solids at the carbon release point 129 for the release of carbon solids. The centrifugal force helps separate solid particles and sediments from the center of the liquid 140. Therefore, positioning the central liquid outlet 128 helps reduce the amount of solid particles and sediments drawn out through the central liquid outlet 128. However, the swirling motion also lowers the upper level of the liquid 140 in the region adjacent to the central axis of the swirl of the liquid 140. In various embodiments, the cracking intensity may vary over time. Therefore, hydrocarbons change into the gas phase at varying intensities over time. As a result, the amount of hydrocarbons in the gas phase within the separator container 12 changes, and the level of the liquid 140 within the separator container 12 fluctuates. The side liquid outlets 127 and the central liquid outlet 128 may temporarily be above the level of the liquid 140 within the separator container 12. In various embodiments, liquid hydrocarbons crack within the entire volume of liquid 140 in the separator container 12. Hydrocarbons in the gas phase typically rise through the liquid 140 towards the upper portion of the separator container 12, but some of the hydrocarbons in the gas phase will be received at the side liquid outlets 127 and / or the central liquid outlet 128. Thus, the side liquid outlets 127 and / or the central liquid outlet 128 are also capable of receiving hydrocarbons in the gas phase. Furthermore, some of the hydrocarbons entering the side liquid outlets 127 or the central liquid outlet in the liquid phase may crack as they pass through the recycle loop 26 before reaching the recycle pump 27. While passing through the recycle loop 26, the hydrocarbons in the gas phase condense and form larger volumes of hydrocarbons in the gas phase.

[0111] Hydrocarbons in the gas phase have different compressibility than hydrocarbons in the liquid phase. When hydrocarbons in the gas phase occasionally reach the recycle pump 27, the load on the recycle pump changes abruptly. Normally, when hydrocarbons in the gas phase reach the recycle pump 27, the recycle pump 27 experiences little resistance at a given pump cycle speed and moves a small mass of hydrocarbons at a given pump cycle speed. This increases the number of pump cycles per hour or rotations per hour of the centrifugal pump, but the recycle pump 27 delivers less hydrocarbons per cycle in terms of mass when the hydrocarbons are in the gas phase. Sometimes the recycle pump 27 may reach operating conditions outside the range of operation that is considered safe for the recycle pump 27. Furthermore, when the hydrocarbons in the recycle pump 27 change to the liquid phase, i.e., when bubbles pass through the recycle pump 27, the recycle pump 27 experiences another abrupt load change. By passing the hydrocarbons through the degassing section 151, the occupancy of hydrocarbons in the gas phase is reduced, and therefore the degassing section 151 reduces the stress on the recycle pump 27.

[0112] Furthermore, when hydrocarbons in the gas phase reach the recycling heat exchanger 28, the section of the recycling heat exchanger 28 heats the already cracked material. This makes the recycling heat exchanger 28 less effective. Hydrocarbons in the gas phase insulate the hydrocarbons in the liquid phase from the portion of the recycling heat exchanger 28. The degassing section 151 makes the recycling heat exchanger 28 more effective.

[0113] In various embodiments, the degassing section 151 is positioned to extend vertically. In various embodiments, the degassing section 151 is configured to allow the liquid 140 to pass downward. In various embodiments, the degassing section 151 is a section of the recycle loop 26 having a larger cross-sectional area than the section of the recycle loop 26 that connects the liquid outlets 128, 127 to the degassing section 151, and the section of the recycle loop 26 that connects the degassing section 151 together with the recycle pump 27. In various embodiments, the size of the hydrocarbon bubbles to be removed from the hydrocarbon in the liquid phase ranges from 200 μm to 500 μm. Bubbles of these sizes rise through and against the liquid 140 at a speed between 0.016 m / s and 0.054 m / s. In various embodiments, the degassing section 151 is positioned to result in a downward velocity of the liquid hydrocarbon that is slower than the upward velocity of the bubbles. Thus, the bubbles rise through the liquid hydrocarbon, while the liquid hydrocarbon passes to the recycle pump 27. In the degassing section 151, the liquid hydrocarbon flows downward at a speed of less than 0.016 m / s to 0.054 m / s.

[0114] In various embodiments, the degassing section 151 includes a degassing outlet line 155. Hydrocarbons in the gas phase rising within the degassing section 151 are released through the degassing outlet line 155 and pass through to the distillation section.

[0115] In various embodiments, the recycle loop 26 comprises at least two degassing sections arranged in parallel with each other. In various embodiments, the recycle loop 26 bifurcates before the two degassing sections, allowing the hydrocarbon fluid to pass through both sections. In various embodiments, this results in a favorable flow pattern for the degassing sections. In various embodiments, the at least two degassing sections are dimensioned to provide a flow pattern with a downward flow velocity that does not exceed the upward velocity of bubbles. In various embodiments, the recycle loop 26 is configured to selectively pass the hydrocarbon fluid through the degassing sections. In various embodiments, each of the degassing sections is configured to selectively bypass the other degassing section. This configuration allows for maintenance of each bypassed degassing section, particularly by removing solids and cleaning. This also makes it possible to use only one degassing tank, thus adapting the volume of the degassing sections to the required throughput of the fluid hydrocarbons. In various embodiments, each of the at least two degassing sections comprises a degassing outlet line. In various embodiments, the hydrocarbons from the degassing sections are combined before the recycle pump 27. In various embodiments, each of the recycling loop branches includes a degassing section.

[0116] In various embodiments, the recycle loop 26 includes a recycle density sensor 153 configured to determine the density of hydrocarbons passing through to the recycle pump 27. Density is generally the mass of a substance per unit volume, and in the context of the present invention, it provides an indicator of the occupancy of hydrocarbons in the gas phase relative to hydrocarbons and char particles in the recycle loop 26. Preferably, both the density in the recycle loop 26 and the density of carbon emission products are measured. The density sensor 153 adjusts the operation of the recycle pump 27 to match the occupancy of hydrocarbons in the gas phase and / or prevents sudden changes in the load generated in the recycle pump 27. This helps to reduce the load on the recycle pump 27. The occupancy of hydrocarbons in the gas phase provides an indicator of the increase in hydrocarbons in the gas phase entering the separator container 12. Thus, the density sensor 153 helps to determine the level of liquid 140 in the separator container 12. In various embodiments, the recycle heat exchanger 28 operates to regulate the level of liquid 140 in the separator container 12. In various embodiments, the recycling heat exchanger 28 operates in response to the density sensor 153 to regulate the level of the liquid 140 in the separator container 12.

[0117] In various embodiments, the separator container 12 includes a carbon emission density sensor 157 adjacent to the carbon emission point 129. In various embodiments, the carbon emission density sensor 157 is configured to determine the density of a certain volume of hydrocarbons in the separator container 12 adjacent to the carbon emission point 129, so as to selectively open the carbon emission point 129 in response to a density measurement of that volume of hydrocarbons. A certain volume of denser hydrocarbons typically has a larger occupancy of solids than a volume of hydrocarbons with a lower density. For example, when a density measurement determines that the density of hydrocarbons adjacent to the carbon emission point 129 has passed a density threshold, the carbon emission point 129 opens to dispose of the hydrocarbons accumulated at the carbon emission point 129. This operation helps to make the frequency of solid disposal dependent on the actual accumulation of solids, preventing the accumulation of fouling to a point where it becomes more difficult to remove. In various embodiments, this avoids the configuration in various embodiments where the carbon emission density sensor 157 is configured to determine the density of a certain volume of hydrocarbons that has passed the carbon emission point 129 and is outside the separator container 12. In various embodiments, the solids are then removed from the hydrocarbons, and at least a portion of the liquid hydrocarbons is recycled back into the original separator container 12. In various embodiments, the density difference between the recycling loop 26 and the carbon release point 129 indicates the occupancy rate of char particles in the hydrocarbons at the carbon release point. We have noticed that various compositions of hydrocarbons supplied to the separator container 12 can result in various densities of the liquid 140. Therefore, in some embodiments, only the measurement of density at the carbon release point 129 can yield very different values, independent of the occupancy rate of char particles at the carbon release point 129. The density of hydrocarbons in the recycling loop 26 has been observed to provide a good indicator of the bulk density of the liquid 140 in the separator container 12. A comparison of the density at the carbon release point 129 and the density in the recycling loop 26 provides, or at least provides, a rough estimate of the occupancy rate of heavy hydrocarbons and / or char particles accumulated at the carbon release point 129. In various embodiments, the frequency of carbon emissions at the carbon emission point is adjusted according to the density difference between the recycling loop 26 and the carbon emission point 129.In various embodiments, heavy hydrocarbons and / or char particles are released when the density difference between the recycling loop 26 and the carbon release point 129 exceeds a threshold.

Claims

1. An apparatus for thermally decomposing a fluid hydrocarbon into one or more hydrocarbon products, - At least one recycle pump for transporting fluid hydrocarbons, - At least one recyclable heat exchanger providing at least one tube through which the fluid hydrocarbon passes Equipped with, The at least one recycling pump and / or the recycling heat exchanger is configured to establish a flow velocity of at least 1 m / s of the fluid hydrocarbon in the at least one pipe. Device.

2. The recycling heat exchanger includes a heat exchange surface that the fluid hydrocarbons come into contact with as they pass through the recycling heat exchanger, and the heat exchange surface has a capacity of at least 8 m³ per 6,000 kg / hour of fluid hydrocarbons passing through the recycling heat exchanger during operation. ２ The apparatus according to claim 1, which provides the minimum heat exchange surface area.

3. - A recycling inlet arranged to receive gaseous and fluid hydrocarbons at the pyrolysis temperature from at least one of the recycling heat exchangers, - An upward outlet for releasing gaseous material, - Downward outlet for releasing fluid hydrocarbons and Equipped with, The apparatus according to claim 1 or 2, further comprising a separator container whose lower outlet is configured to pass the fluid hydrocarbon to at least one recycle pump.

4. The separator container further comprises a separator container inlet arranged to allow a supply gas and fluid hydrocarbons at a fresh pyrolysis temperature to pass into the separator container. The recycling heat exchanger includes a heat exchange surface into which the fluid hydrocarbons come into contact as they pass through the recycling heat exchanger, and the heat exchange surface is at least 80 m³ per 3000 kg / hour of fresh supply fluid hydrocarbons entering the separator container during operation. ２ The apparatus according to claim 3, which provides the minimum heat exchange surface area.

5. The apparatus according to claim 4, wherein the flow rate ratio of the fluid hydrocarbon entering the separator container through the separator container inlet and the fluid hydrocarbon exiting the separator container through the lower outlet is configured to be between 1:1 and 1:

20.

6. The apparatus according to any one of claims 3 to 5, wherein the at least one recycling pump is provided with a fluid hydrocarbon inlet, and the separator container is configured to have an upper level of the fluid hydrocarbon at least 7 meters above the fluid hydrocarbon inlet.

7. The apparatus according to any one of claims 3 to 6, comprising a recycling pipe, wherein the recycling pipe is configured to pass the fluid hydrocarbon from the lower outlet of the separator container to the at least one recycling pump, and the recycling pipe is configured to cool the fluid hydrocarbon as it passes to the at least one recycling pump.

8. The apparatus according to any one of claims 3 to 7, comprising: a carbon release point configured to dispose of heavy hydrocarbons, char particles, and / or solid carbon from the separator container; and a carbon release density sensor adjacent to the carbon release point configured to determine the density of a certain volume of hydrocarbons in the separator container adjacent to the carbon release point, wherein the carbon release point is configured to selectively dispose of the heavy hydrocarbons, char particles, and / or solid carbon according to the density of the certain volume of hydrocarbons.

9. The apparatus according to any one of claims 1 to 8, wherein the at least one recycling heat exchanger is configured to expose the fluid hydrocarbons to a temperature up to 50°C higher than the temperature of each fluid hydrocarbon, preferably up to 30°C higher than the temperature of each fluid hydrocarbon.

10. The apparatus according to any one of claims 1 to 9, further comprising a back pressure control element configured to maintain the fluid hydrocarbon in at least one recirculating heat exchanger at a pressure of at least 2 bar, preferably at least 5 bar, more preferably at least 15 bar, wherein the back pressure control element is preferably located downstream of the recirculating heat exchanger.

11. The apparatus according to any one of claims 1 to 10, wherein the at least one recycling pump is a centrifugal pump and / or is located upstream of the recycling heat exchanger.

12. The apparatus according to any one of claims 1 to 11, further comprising at least one heating element configured to selectively heat at least one section of the apparatus.

13. The apparatus according to any one of claims 1 to 12, comprising at least two recyclable heat exchangers, configured to selectively pass a fluid hydrocarbon through only one of the at least two recyclable heat exchangers.

14. The apparatus according to any one of claims 1 to 13, further comprising at least one degassing section configured to reduce the proportion of hydrocarbons in the gas phase from the fluid hydrocarbons before they enter the recycling pump.

15. The apparatus according to claim 14, wherein the degassing section extends vertically and is configured to allow the fluid hydrocarbon to pass downward.

16. The apparatus according to claim 14 or 15, wherein the degassing section is configured to establish a downward flow velocity of the fluid hydrocarbon of less than 0.054 m / sec.

17. The apparatus according to any one of claims 14 to 16, comprising at least two degassing sections arranged parallel to each other.

18. The apparatus according to any one of claims 1 to 17, further comprising a recycling density sensor configured to determine the density of the fluid hydrocarbon passing through to the recycling pump.

19. The apparatus according to any one of claims 1 to 18, comprising a control element having a microprocessor and memory, wherein the memory stores, when executed by the microprocessor, an instruction to operate the apparatus for thermally decomposing a fluid hydrocarbon according to any one of claims 1 to 18.

20. The apparatus according to claim 19, comprising the carbon emission point and carbon emission density sensor according to claim 8 and the recycling density sensor according to claim 18, wherein the microprocessor is configured to compare the densities indicated by the carbon emission density sensor and the recycling density sensor, and to operate the carbon emission point according to the result of the comparison of the densities.

21. A method for thermally decomposing a fluid hydrocarbon, - A step of supplying gaseous and fluid hydrocarbons at the thermal decomposition temperature through a heat exchanger, - A step of establishing a flow velocity of at least 1 m / s of a fluid hydrocarbon in at least one pipe. Methods that include...

22. - Steps include setting up a separator container, - A step of receiving gaseous and fluid hydrocarbons at the thermal decomposition temperature from the heat exchanger at the recycling inlet of the separator container, - The step of releasing the gaseous material at the upper outlet of the separator container, - The step of releasing the fluid hydrocarbon at the lower outlet of the separator container. The method according to claim 21, further comprising the lower outlet passing the fluid hydrocarbon to the at least one recycle pump.

23. The method according to claim 21 or 22, wherein the heat exchanger exposes the fluid hydrocarbons to a temperature up to 50°C higher than the temperature of each of the fluid hydrocarbons, preferably up to 30°C higher than the temperature of each of the fluid hydrocarbons.

24. A control element comprising a microprocessor and memory, wherein the memory stores, when executed by the microprocessor, an instruction to operate an apparatus for thermally decomposing a fluid hydrocarbon according to any one of claims 1 to 20 in order to carry out the method for thermally decomposing a fluid hydrocarbon according to any one of claims 21 to 23.

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