Feed nozzle assembly

Abstract

A feed nozzle assembly for co-current introduction of steam and liquid into a reaction vessel, the feed nozzle assembly comprising: (a) an annular housing surrounding an annular feed conduit; (b) an atomized steam conduit surrounded by the annular feed conduit. The annular feed conduit includes a first portion having a first outlet and a second portion having a second outlet opposite the first outlet. The first outlet fluidly connects the first portion and the second portion. The second portion is lined with a non-metallic conduit. The second outlet of the annular feed conduit traverses the annular housing. The atomized vapor conduit has an outlet end with one or more openings disposed upstream of the first outlet of the annular feed conduit.

Description

Technical Field

[0001] The present invention relates to a feed nozzle for introducing gas and liquid into a reaction vessel in parallel, in particular to a feed nozzle for introducing atomized steam and pyrolysis oil feed into a catalytic cracking reactor. Background Art

[0002] Many refineries and chemical plant units utilize nozzles to distribute liquid and / or gaseous feeds to the units. In some processes, the ability of the nozzles to distribute the feeds to the units is important for the unit's productivity. An example of such a process is fluid catalytic cracking, in which the large chain hydrocarbon molecules present in crude oil are cracked into smaller and more valuable commercial products, such as gasoline-range hydrocarbons and diesel, with the help of a catalyst. Typically, hydrocarbons are introduced through a feed nozzle in the reactor, where the feed comes into contact with a regenerated particulate solid catalyst. The catalyst selectively assists the desired cracking reaction.

[0003] Such a feed nozzle may include an inner tube defining a steam conduit and an outer tube disposed about the inner tube, wherein an outer surface of the inner tube and an inner surface of the outer tube define an annular hydrocarbon conduit, and wherein each tube has an inlet end and an opposing outlet end.

[0004] Petroleum hydrocarbon streams such as vacuum gas oil or atmospheric residue have typically been upgraded through FCC processes. However, there is an increasing desire to upgrade heat-sensitive and / or non-petroleum-based hydrocarbons (i.e., renewable and recycled sources) along with the hydrocarbon stream in the FCC process. By upgrading heat-sensitive and / or non-petroleum-based hydrocarbons along with the hydrocarbon stream, the resulting upgraded fuel contains renewable components and the net content of petroleum-based hydrocarbons in the upgraded fuel can be reduced.

[0005] Heat-sensitive feeds include both petroleum and non-petroleum feeds, which can be unstable at the operating temperatures of many refining / chemical processes. This instability can cause the heat-sensitive feeds to polymerize or degrade in process equipment. Examples of such feeds include, but are not limited to, products resulting from the pyrolysis of biomass, plastics, waste, and hydrocarbons, which contain low-boiling components that are volatile at near-ambient conditions.

[0006] Non-petroleum-based hydrocarbons include biofuels derived from organic biomass, particularly pyrolysis oil, which is also commonly referred to as biomass-derived pyrolysis oil. Pyrolysis oil is produced by pyrolysis, including by the recently developed fast pyrolysis process. Pyrolysis oil is a complex, highly oxygenated organic liquid that typically contains 20% to 30% by weight of water with high acidity (total acid number (TAN)>10). In other embodiments, pyrolysis oil can be derived from recycled plastics or processed pyrolysis oil, i.e., feed with low oxygen or low water content.

[0007] When injected into an FCC unit, pyrolysis oil and / or heat-sensitive feedstock tend to degrade, coke, foul equipment, or vaporize prematurely as the feedstock temperature increases. Injection can occur in the riser and / or fluidized catalyst bed. Previous attempts to co-process pyrolysis oil and hydrocarbon streams have involved deoxygenating the pyrolysis oil. This approach adds unit operations to the upgrading process and also increases capital costs. Feedlines containing a mixture of hydrocarbon and pyrolysis oil streams are often susceptible to plugging due to the presence of the pyrolysis oil stream in the feedline.

[0008] Modifications to the feed nozzle have been explored to incorporate coolant flow and / or mechanical cleaning devices into the feed injector for coking / fouling conditions. The coolant flow, which can be gaseous or liquid, helps remove heat from the heat-sensitive feedstock. Any coking / fouling that may occur can be mechanically removed with a cleaning device that scrubs or scrapes the interior surfaces of the feed injector at a certain frequency.

[0009] However, both modifications have several disadvantages. Coolant flow can adversely affect the mixing of the injected feedstock with the circulating catalyst flowing in the FCC riser, leading to poor yield structure. Gaseous coolants can increase the load on the wet gas compressor, which can become a limiting operating parameter of the process. Liquid coolants also need to be atomized like the feedstock to achieve good mixing with the catalyst. Both coolant types increase the complexity of the injector design and the piping network used to operate the injector.

[0010] The mechanical device for removing coke / fouling is operated automatically or manually via the shaft. There is a risk that the device will become detached from the shaft or that the packing around the shaft will leak process material into the atmosphere.

[0011] WO2015 / 119598 describes a feed distributor comprising a pyrolysis oil feed pipe and a hydrocarbon feed pipe. Each feed pipe has an outlet leading to a mixing zone, for introducing a hydrocarbon stream and a pyrolysis oil stream into the mixing zone. The hydrocarbon stream and the pyrolysis oil stream mix in the mixing zone to form a mixture of the pyrolysis oil and hydrocarbon streams. The mixture of the pyrolysis oil and hydrocarbon streams is then introduced into a reaction zone, where it is catalytically cracked in the presence of a particulate cracking catalyst.

[0012] It would therefore be desirable to provide methods and apparatus capable of upgrading heat sensitive feeds and / or mixtures comprising heat sensitive feeds (such as pyrolysis oil) and hydrocarbon streams by catalytic cracking (such as in a fluid catalytic cracking unit) while avoiding excessive plugging of the feed lines. Summary of the Invention

[0013] A feed nozzle assembly for introducing steam and liquid into a reaction vessel in parallel, the feed nozzle assembly comprising: (a) an annular housing surrounding an annular feed conduit; and (b) an atomizing steam conduit surrounded by the annular feed conduit. The annular feed conduit comprises a first portion and a second portion, the first portion having a first outlet and the second portion having a second outlet opposite the first outlet. The first outlet fluidly connects the first portion and the second portion. The second portion is lined with a non-metallic conduit. The second outlet of the annular feed conduit traverses the annular housing. The atomizing steam conduit has an outlet end having one or more openings disposed upstream of the first outlet of the annular feed conduit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A longitudinal section of a feed nozzle assembly of the present invention is shown.

[0015] Figure 2 Shown is the insertion into the container Figure 1 Longitudinal section of the feed nozzle assembly.

[0016] Figure 3 The maximum difference between the wall temperature and the feedstock temperature is shown for the case where the feed nozzle assembly contains non-metallic conduits. DETAILED DESCRIPTION

[0017] The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

[0018] Provided herein are methods and fuel processing equipment for feeding liquid and steam feeds to a process. In one embodiment, provided herein are processes for upgrading a heat-sensitive stream (such as a pyrolysis oil product stream). As referred to herein, "upgrading" refers to converting relatively high-boiling hydrocarbons into lower-boiling hydrocarbons. These feedstocks can be fossil or non-fossil feedstocks. The upgrading process typically makes the heat-sensitive stream suitable for use as a transportation fuel and other valuable products, such as olefins. In the methods and fuel processing equipment described herein, the heat-sensitive stream is catalytically cracked in the presence of a particulate cracking catalyst in a reaction zone. As referred to herein, the reaction zone is the area or space where the particulate cracking catalyst is mixed with the heat-sensitive stream. Catalytic cracking is carried out at temperatures exceeding 100°C. In some embodiments, the heat-sensitive stream may polymerize at temperatures exceeding 25°C and form deposits within the equipment. Sediment formation is a concern in the feed lines leading to the reaction / riser zone.

[0019] Deposits formed in the feed pipes leading to the reaction zone may cause blockages, which may require shutting down the fuel processing equipment and cleaning the blocked feed pipes. In order to minimize the temperature rise of the pyrolysis oil stream according to the embodiments described herein, the pyrolysis oil stream is insulated in the feed nozzle by a heat shield. In some embodiments, the heat shield surrounds the pyrolysis oil stream, which helps to keep the temperature of the pyrolysis oil stream substantially at a temperature of less than or equal to about 160°C until it is introduced into the reaction zone. Without wishing to be bound by any particular theory, it is believed that the temperature rise in the pyrolysis oil stream to above about 160°C may cause deposit formation due to polymerization within the pyrolysis oil stream. By keeping the temperature of the pyrolysis oil stream substantially at a temperature of less than or equal to about 160°C until it is introduced into the reaction zone, at least when the pyrolysis oil stream is in a fuel nozzle outside the reaction zone, deposit formation (which may cause blockages) before the pyrolysis oil stream is introduced into the reaction zone is minimized.

[0020] In some embodiments, the feed nozzle can be used in various reaction vessels and various operating modes, such as but not limited to upflow, downflow, riser or fluidized bed.In some embodiments, the feed nozzle can be used in many processes, where it is desired to insulate the feed from external sources.

[0021] Now refer to Figure 1 1 and 2 to illustrate an exemplary embodiment of a feed nozzle. The feed nozzle assembly 100 includes an annular housing 102 surrounding an annular feed conduit 104. The annular feed conduit 104 has a first portion 130 and a second portion 114. In some embodiments, the length of the second portion 114 is less than the length of the first portion 130. In some embodiments, the inner diameter of the second portion 114 can be less than the inner diameter of the first portion 130. In other embodiments, the inner diameter of the second portion 114 can be equal to or greater than the inner diameter of the first portion 130. The first portion 130 has an inlet end 106 and an outlet end 108. The outlet end 108 has an opening 110 that fluidly connects the first portion 130 to the second portion 114. The second portion 114 has an outlet 112 opposite the opening 110. The outlet 112 traverses the annular housing 102.

[0022] The first portion 130 of the annular feed conduit 104 surrounds the atomizing steam conduit 116. The atomizing steam conduit 116 has an inlet end 118 and an outlet end 120. The outlet end 120 includes one or more openings 122, from which atomizing steam is discharged. In some embodiments, the one or more openings 122 are disposed upstream of the opening 110, creating an atomizing zone in the outlet end 108 of the annular feed conduit 104, wherein the atomizing steam atomizes the feed. The length between the one or more openings 122 and the opening 110 can be determined by one skilled in the art.

[0023] The inner diameter of the annular housing 102 is greater than the outer diameter of the first portion 130 of the annular feed conduit 104. The inner diameter of the annular housing 102 is greater than the outer diameter of the second portion 114 of the annular feed conduit 104. The inner diameter of the first portion 130 of the annular feed conduit 104 is greater than the outer diameter of the atomizing steam conduit 116. In some embodiments, the inner diameter of the second portion 114 is less than or equal to the inner diameter of the atomizing steam conduit 116. In some embodiments, the inner diameter of the second portion 114 is greater than the inner diameter of the atomizing steam conduit 116.

[0024] Annular housing 102 thermally insulates annular feed conduit 104. The inner diameter and outer diameter of annular housing 102 and the wall thickness of the conduit can be determined by a person skilled in the art. Annular housing 102 can be made of materials commonly used in the refining / chemical processing fields, such as, but not limited to, stainless steel or other types of steel. Annular housing 102 is hollow and can be filled with one or more insulating materials.

[0025] In some embodiments, the thermal conductivity of the insulating material can be 0.0017 W / (m-°K) to 1.73 W / (m-°K), 0.017 W / (m-°K) to 0.865 W / (m-°K), or 0.173 W / (m-°K) to 0.519 W / (m-°K). In some embodiments, the insulating material can be gaseous, such as, but not limited to, air or an inert gas. The thermal conductivity of the gaseous insulating material can be 0.0173 W / (m-°K) to 0.432 W / (m-°K), 0.0865 W / (m-°K) to 0.259 W / (m-°K), or 0.13 W / (m-°K) to 0.173 W / (m-°K). In other embodiments, the air or inert gas in the annular housing 102 is removed to create a vacuum, thereby further reducing the thermal conductivity.

[0026] In some embodiments, the annular housing 102 may be filled with one or more solid insulation materials. The thermal conductivity of the solid insulation material may be 0.0017 W / (m-°K) to 1.73 W / (m-°K), 0.017 W / (m-°K) to 1.3 W / (m-°K), or 0.173 W / (m-°K) to 0.865 W / (m-°K). In some embodiments, the insulation material may be selected from, but not limited to, pellets, heater / boiler insulation, residential insulation, and the like.

[0027] In some embodiments, after the annular housing 102 has been filled with the insulating material, a vacuum can be drawn to evacuate any remaining gas within the annular conduit, thereby further reducing thermal conductivity. These insulating materials can provide a thermal barrier at least equivalent to that of air while enabling a more compact device design. Furthermore, these insulating materials are available in a variety of forms (e.g., insulation felt, rope, granules) to accommodate various types of annular conduits 102. Installing such materials within a cavity, gap, or annular space containing air displaces the volume occupied by the air, thereby limiting pressure buildup within the device as temperatures rise during operation.

[0028] The annular feed conduit 104 can be made of a material commonly used in the refining / chemical processing field that is resistant to corrosion by acidic liquids, such as, but not limited to, stainless steel or other types of steel. The inner diameters of the first and second portions 130 of the annular feed conduit 104, the outer diameters of the first and second portions 130 of the annular feed conduit 104, and the thickness of the conduit wall can be determined by a person skilled in the art.

[0029] In another embodiment, the second portion 114 surrounds a non-metallic conduit 150. The non-metallic conduit 150 can be cylindrical. In some embodiments, the inner diameter of the non-metallic conduit 150 can be less than or equal to the inner diameter of the atomizing steam conduit 116. In other embodiments, the inner diameter of the non-metallic conduit 150 can be greater than the inner diameter of the atomizing steam conduit 116. The inner diameter of the non-metallic conduit 150, the outer diameter of the non-metallic conduit 150, and the thickness of the conduit can be determined by one skilled in the art.

[0030] The thermal conductivity of the non-metallic conduit 150 can be less than the thermal conductivity of the material of the second portion 114. In some embodiments, the non-metallic conduit 150 can be a thermally insulating material or a composite material of thermally insulating materials. The thermal conductivity of the thermally insulating material can be 0.0432 W / (m-°K) to about 3.46 W / (m-°K), 0.0865 W / (m-°K) to 1.73 W / (m-°K), or 0.173 W / (m-°K) to 0.865 W / (m-°K). In some embodiments, the non-metallic material can be selected from low thermal conductivity materials such as, but not limited to, ceramics, including examples such as high alumina ceramics and fused silica ceramics. The thermal conductivities of some examples of non-metallic materials are shown in Table 1.

[0031] Table 1: Thermal conductivity of common non-metallic materials

[0032]

[0033] The atomizing steam conduit 116 can be made of a material commonly used in the refining / chemical processing field that is resistant to corrosion by acidic liquids, such as, but not limited to, stainless steel or other types of steel. The inner diameter and outer diameter of the atomizing steam conduit 116 and the thickness of the conduit wall can be determined by those skilled in the art. The number and spacing of the openings 122 can also be determined by those skilled in the art.

[0034] refer to Figure 2 In some embodiments, the feed nozzle assembly 100 can be inserted into a vessel 300 having a sidewall 301. The vessel 300 can be a reactor or a riser. The thickness of the sidewall 301 can be determined by one skilled in the art. For clarity, the same reference numerals are used throughout the drawings to represent the same terms. In some embodiments, the feed nozzle assembly 100 can be inserted into any surface of the vessel 300 (i.e., the top, bottom, or side).

[0035] In some embodiments, the feed nozzle assembly 100 is inserted into a nozzle sleeve 202, which is surrounded by a refractory shroud 204. The refractory shroud 204 is typically embedded in the vessel 300 and may or may not extend beyond the sidewall 301. In some embodiments, the feed nozzle assembly 100 can be inserted into the vessel 300 without the nozzle sleeve 202. In other embodiments, the feed nozzle assembly 100 can be inserted into any suitable nozzle or suitable opening in the vessel 300. The nozzle sleeve 202 extends through the sidewall 301 into the reaction zone 302. The feed nozzle assembly 100 and nozzle sleeve 202 are typically oriented into the reaction zone 302 at an angle of 0 to 90 degrees from horizontal, typically at an angle of 45 degrees from horizontal, such as Figure 2 shown.

[0036] If the feed nozzle assembly 100 is inserted near the main reaction flow path in the reaction zone 302, it may be subjected to the most severe reactor process conditions. If the feed nozzle assembly 100 is inserted near or adjacent to the main reaction flow path, the feed nozzle assembly 100 will be subjected to less severe conditions, but will still be subjected to high temperature process conditions. In some embodiments, when the process flow path in the reaction zone 302 is assumed to be vertically upward, the lower side of the feed nozzle assembly 100 is exposed to the heat of the reactor zone 302 to a greater extent than the upper side of the feed nozzle. The nozzle sleeve 202 and the refractory shield 204 provide some thermal shielding for the feed nozzle assembly 100, but the feed nozzle assembly 100 is still significantly exposed to high temperatures.

[0037] One of ordinary skill in the art will be able to design and construct the nozzle sleeve 202 positioned within the sidewall 301 of the vessel 300. A passage 214 traverses the nozzle sleeve 202 and the refractory shield 204. The passage 214 forms a fluid conduit from the outlet 112 of the second portion 114 to the inlet 216 and then through the outlet 218. The outlet 218 is opposite the inlet 216. The outlet 218 of the passage 214 is positioned within the reactor region 302. In some embodiments, the nozzle sleeve 202 is constructed of metal, such as stainless steel, and the refractory shield 204 is constructed of a refractory material. The composition and dimensions of the nozzle sleeve 202 and the refractory shield 204 can be determined by one of ordinary skill in the art.

[0038] During normal operation of the feed nozzle assembly 100 according to an embodiment of the present invention, atomizing steam passes through the atomizing steam conduit 116 from the inlet end 118 along the atomizing steam conduit 116 and exits the atomizing steam conduit 116 through the opening 122. Pyrolysis oil is supplied to the inlet end 106 of the annular feed conduit 104 and conveyed along the annular feed conduit 104.

[0039] Atomized steam is discharged from one or more openings 122 and mixes with the pyrolysis oil in the annular feed conduit 104, producing a fine jet of dispersed pyrolysis oil. The mixture of atomized steam and pyrolysis oil passes through opening 110 along the non-metallic conduit 150 and is discharged through opening 112 of the annular housing 102. The one or more openings 122 are used to substantially uniformly atomize the mixture of atomized steam and pyrolysis oil before it enters opening 110. In some embodiments, opening 112 is aligned with passage 214 for discharge into vessel 300 via outlet 218. The vessel may be, but is not limited to, a fluidized catalytic cracking reactor.

[0040] The pyrolysis oil in the second portion 114 is shielded from the heat of the container 300 by the non-metallic conduit 150. The heat shielding capability of the non-metallic conduit 150 against the non-metallic insulation material is evaluated in the following examples.

[0041] For analysis, the annular housing 102 was filled with a granular material having thermal conductivities as shown in Table 2:

[0042] Table 2: Thermal conductivity of granular materials

[0043]

[0044] In Example 1, a finite element analysis was performed to predict the thermal gradients of specific feed nozzle interior surfaces under various process operating conditions. Of greatest concern were the temperatures of the interior surfaces of the non-metallic conduit 150, which contact the aforementioned heat-sensitive feedstock. Shielding the interior surfaces of the non-metallic conduit 150 from reaching excessive temperatures mitigated potential coking and scaling of the heat-sensitive feedstock within the feed nozzle assembly 100. In other words, the thermal shielding provided by the non-metallic conduit 150 minimized the difference between the heat-sensitive feedstock inlet temperature at the inlet end 106 and the surface temperatures of the internal contact surfaces, such as the annular feedstock conduit 104, the outlet end 108, the opening 110, the non-metallic conduit 150, and the outlet 112.

[0045] refer to Figure 1 , the feed nozzle assembly 100 was modeled so that the temperature of the heat-sensitive feedstock entering the opening 110 could be compared to the predicted wall temperature along the non-metallic conduit 150 to the outlet 112. The annular housing 102 was modeled as being filled with a particulate material having the properties shown in Table 2. In one example, the annular housing 102 was exposed to process steam having a temperature of approximately 345°C. For a typical feed nozzle assembly 100 operating range, the maximum temperature difference between any predicted non-metallic conduit 150 wall temperature along its length and the temperature of the heat-sensitive feedstock entering the opening 110 was approximately 8°C (see Figure 3 This lower temperature increase enables the heat sensitive feedstock to be maintained at a temperature of less than or equal to about 160° C. until introduced into the reaction zone 302 .

[0046] Although several embodiments of the present disclosure have been described in detail above, it will be readily apparent to those skilled in the art that many modifications may be made without departing substantially from the teachings of the present disclosure. Therefore, such modifications are intended to be included within the scope of the present disclosure as defined by the claims.

Claims

1. A feed nozzle assembly for introducing steam and liquid into a reaction vessel in parallel, the feed nozzle assembly comprising: (a) an annular housing surrounding an annular feed conduit, (b) an atomizing steam conduit, said atomizing steam conduit being surrounded by said annular feed conduit, wherein the annular feed conduit comprises a first portion and a second portion, the first portion having a first outlet, the second portion comprising a second outlet opposite the first outlet, the first outlet fluidly connecting the first portion and the second portion, wherein the second portion is lined with a non-metallic conduit, wherein the second outlet of the annular feed conduit traverses the annular housing, and The atomizing steam conduit has an outlet end, and the outlet end includes one or more openings arranged upstream of the first outlet of the annular feed conduit. 2 . The feed nozzle assembly of claim 1 , wherein an inner diameter of the second portion of the annular feed conduit is less than or equal to an inner diameter of the first portion of the annular feed conduit. 3 . The feed nozzle assembly of claim 1 , wherein the inner diameter of the second portion of the annular feed conduit is greater than or equal to the inner diameter of the first portion of the annular feed conduit. 4 . The feed nozzle assembly of claim 1 , wherein a length of the second portion of the annular feed conduit is less than or equal to a length of the first portion of the annular feed conduit. 5 . The feed nozzle assembly of claim 1 , wherein the inner diameter of the annular housing is greater than the outer diameter of the annular feed conduit. 6 . The feed nozzle assembly of claim 1 , wherein the inner diameter of the first portion of the annular feed conduit is greater than the outer diameter of the atomizing steam conduit. 7 . The feed nozzle assembly of claim 1 , wherein the inner diameter of the second portion of the annular feed conduit is less than or equal to the inner diameter of the atomizing steam conduit.

8. The feed nozzle assembly of claim 1, wherein the non-metallic conduit has a thermal conductivity of about 0.173 W / (m-°K) to about 3.46 W / (m-°K).

9. The feed nozzle of claim 8, wherein the non-metallic conduit is a high alumina ceramic.

10. The feed nozzle of claim 8, wherein the non-metallic conduit is fused silica ceramic.

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