Process and apparatus for heating hydrocarbon process streams

Abstract

A process and apparatus for heating a hydrocarbon process stream using an electric heater to provide a portion of the heat requirement necessary to chemically react one of the components of the hydrocarbon process stream. The electric heater may be in series or parallel with a secondary or primary heater. The electric heater may be used between two reaction zones or between a feed exchange heater and a first reaction zone. The electric heater preferably provides 5 to 40% of the heat requirement of the process stream.

Description

[Technical Field]

[0001] (Priority statement) This application claims priority to U.S. Provisional Patent Application No. 63 / 387,404, filed December 14, 2022, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present invention relates generally to processes and apparatus for heating hydrocarbon process streams, and more particularly to processes and apparatus that use electric heaters to provide a portion of the heat requirements of a hydrocarbon process stream. [Background technology]

[0003] The world is moving towards greener and cleaner technologies. In light of the Paris Agreement, most countries have targets to become carbon neutral by 2030 or 2050.

[0004] Also in light of the Paris Agreement, there is an increased focus on reducing fossil fuel consumption, improving efficiency to reduce carbon dioxide emissions, and increasing reliance on renewable energy sources. As the refining and petrochemical industries turn to sustainable energy sources such as solar, wind, hydroelectric, and nuclear power, and more green electricity becomes available, there is a desire to reduce the size of fired heaters for technologies such as hydrocarbon reforming, dehydrogenation, isomerization, transalkylation, and hydrotreating.

[0005] Therefore, it would be desirable to have a more effective and efficient method for heating process streams to desired or required temperatures that reduces reliance on heating equipment and processes that generate carbon dioxide. Summary of the Invention

[0006] The present invention addresses these problems by providing a process and apparatus that utilizes electrical in-line heating and heaters in conjunction with main or primary heaters in various hydrocarbon processing zones and equipment. In addition to reducing the carbon dioxide produced in such heaters, the present invention allows for the use of smaller fired heaters, thereby reducing plot space for process units of similar capacity.

[0007] Incorporating in-line electrical heating can also help reduce the process outlet temperature from the fired heater, resulting in lower tube wall and peak film temperatures, which can help mitigate problems such as metal-catalyzed coking (MCC) and thermal (non-selective) cracking, which are reduced with lower heater outlet temperatures in various reforming technologies.

[0008] Electric heating also provides excellent turndown capabilities, offering operational and process flexibility to operate at lower heat loads that cannot be easily achieved with fired heaters, or that cannot be achieved with fired heaters while maintaining efficient or clean combustion of the fuel gas.

[0009] This flexibility can be useful for precise process control, turndown operations, and start-up operations, especially when controlled heating rates of the reactor loop equipment are important. For example, electric heaters can eliminate the need for burners and additional controls designed for low-flow, low-fire operation required during start-up.

[0010] Furthermore, in many reformers, increased unit capacity (such as BPSD) is required for technologies such as reforming, and additional heater cells (helper / auxiliary heaters) are required. The additional heater cells, arranged either in series or parallel, not only increase the required plot space but also present challenges to the layout of transfer piping relative to the reactor location. Integrating electric heaters into the transfer lines (to achieve in-line heating) utilizes the transfer lines (already in the plot plan) and reduces the need or size of the helper / auxiliary heaters, which in turn reduces the plot space requirements and alleviates challenges with thermal expansion and stress issues in the transfer lines relative to the reactor.

[0011] The process fluid temperature at the fired heater outlet will be lower, and the final portion of the heating can occur in the "in-line electric heater." Thus, the solution in this invention not only reduces the high temperature volume, but also reduces the thermal expansion temperature effect of the fired heater on the transfer line, thus relieving some of the line stress.

[0012] Plot space constraints and capacity increase challenges for retrofitted processing units can be addressed with in-line electric heating by integrating with existing fired heaters. In some retrofits of existing reforming units, steam system equipment (such as steam drums, BFW circulation pumps, etc.) can be limiting. By using in-line electric heaters to provide the additional heat load for the retrofit, the steam system equipment on the existing fired heaters does not need to be modified.

[0013] In addition to providing electric heaters in the transfer lines, the present invention also contemplates providing electric heating elements inside the reactor, potentially further reducing the hot volume while providing the same benefits as above.

[0014] While this design is applicable to both new and retrofit designs, the invention is believed to be particularly beneficial as part of a retrofit solution to achieve carbon dioxide reduction.

[0015] By incorporating "in-line electric heating" into hydrocarbon reforming and similar technologies, it is believed that the size of each fired heater service (both charge heaters and inter-reactor heaters) can be reduced by at least 10-20%. Furthermore, lower heater exit temperatures (10-20°F or more lower) further optimize heat flux, facilitating the reduction in fired heater size.

[0016] Thus, in at least one aspect, the present invention can be characterized as providing a chemical reaction process zone having at least one reaction zone having a reactor for receiving a feed stream and causing a chemical reaction of components of the feed stream under suitable conditions, and a heating zone configured to provide heat to the feed stream upstream of the at least one reaction zone, the heating zone including an electric heater configured to provide a first portion of a required amount of heat to the feed stream and a second heater configured to provide a second portion of the required amount of heat to the feed stream, the first and second portions achieving a minimum temperature, and the second heater being either a fired heater or an electric heater.

[0017] At least one reaction zone may include two reactors, and the electric heater may be disposed in a transfer line between the first and second reactors.

[0018] The electric heater may be positioned in the transfer line upstream of the second heater.

[0019] The electric heater may be positioned in the transfer line downstream of the second heater.

[0020] The electric heater may be located inside the reactor containing the catalyst bed, before the catalyst bed.

[0021] The electric heater may be located inside the reactor containing the catalyst bed, after the catalyst bed.

[0022] The electric heater may be located inside a reactor having multiple catalyst beds, and the electric heater may be located after a catalyst bed and before a second catalyst bed.

[0023] The first portion of the required heat amount may be 5% to 40% of the required heat amount.

[0024] The electric heater may be installed at an elbow location in the transfer line, and the feed stream may flow parallel to the electric heater in the transfer line.

[0025] The electric heater may be installed in the transfer line and the feed stream may flow perpendicular to the electric heater.

[0026] The electric heater may be installed in the transfer line in an arrangement configured to cover the entire cross section of the transfer line.

[0027] The second heater may be a combustion heater, and the electric heater may be placed in series with the combustion heater.

[0028] The second heater may be a combustion heater, and the electric heater may be placed in parallel with the combustion heater.

[0029] The chemical reaction process zone may further include a second electric heater disposed in series with the fired heater.

[0030] In a second aspect, the invention may generally be characterized as a process for chemical reaction by heating a process stream in an electric heater; heating the process stream in a second heater, where the second heater is either a fired heater or an electric heater; passing the process stream through a reactor in a reaction zone whereby chemical reaction of components of the feed stream occurs under suitable conditions; and recovering an effluent stream from the reactor.

[0031] The electric heater may be upstream of the second heater.

[0032] The electric heater may be downstream of the second heater.

[0033] The second heater may be a combustion heater, and the electric heater may be placed in series with the combustion heater.

[0034] The second heater may be a combustion heater, and the electric heater may be placed in parallel with the combustion heater.

[0035] The process may further include a second electric heater disposed in series with the fired heater.

[0036] Electric heaters can provide 5% to 40% of the heat required for a chemical reaction.

[0037] The process stream may be the effluent from an upstream reactor in the reaction zone.

[0038] Further aspects, embodiments and details of the invention, all of which may be combined in any manner, are set out in the detailed description of the invention below. [Brief explanation of the drawings]

[0039] One or more exemplary embodiments of the invention are described below in conjunction with the following drawing figures. [Figure 1] FIG. 1 is a process flow diagram according to one or more embodiments of the present invention. [Figure 2] 1 is a simplified cross-sectional side view of an in-line heater according to one or more embodiments of the present invention. [Figure 3] FIG. 2 is another simplified cross-sectional side view of an in-line heater according to one or more embodiments of the present invention. [Figure 4] FIG. 1 is a side schematic view of an in-line heater according to one or more embodiments of the present invention. [Figure 5] FIG. 5 is a cross-sectional view taken along line AA of FIG. 4, in accordance with one or more embodiments of the present invention. [Figure 6] FIG. 5 is a cross-sectional view taken along line AA of FIG. 4, in accordance with one or more embodiments of the present invention. [Figure 7] FIG. 5 is a cross-sectional view taken along line AA of FIG. 4, in accordance with one or more embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] As mentioned above, the present invention proposes in-line electric heating utilized in conjunction with other primary heaters. The use of electric heaters addresses multiple issues, providing greater fuel efficiency over fired heaters, reduced carbon dioxide emissions, lower hot volume, higher yields, less plot space for the fired heater, and lower stress values ​​for the transfer lines.

[0041] With these general principles in mind, one or more embodiments of the invention are described below with the understanding that the description is not intended to be limiting.

[0042] As shown in Figure 1, chemical reaction zone 10 includes at least one reaction zone 11 having a reactor 12 that receives a feed stream 14. Within reactor 12, there may be a catalyst bed 16 that catalyzes a chemical reaction of the components of feed stream 14 under suitable conditions, resulting in reactor 12 producing at least one effluent stream 18. Alternatively, reactor 12 may not include a catalyst bed, and the chemical reaction zone may proceed without a catalyst. Feed stream 14 may be an effluent or partial effluent from another reactor 12 within reaction zone 11.

[0043] In order for the desired chemical reaction to occur, feed stream 14 must be heated to a desired or required temperature. In other words, there is a required amount of heat in feed stream 14. Therefore, chemical reaction zone 10 also includes heating zone 20 to provide heat to feed stream 14 upstream of reaction zone 11.

[0044] Heating zone 20 includes one or more electric heaters 22 and a second heater 24. Electric heater 22 is configured to provide a first portion of the required heat quantity of feed stream 14. Second heater 24 is configured to provide a second portion of the required heat quantity of feed stream 14. The first and second portions together achieve a minimum temperature. Second heater 24 is either a combustion heater or an electric heater. Preferably, electric heaters 22 together provide 5 to 40% or more, or 5 to 20% or more, of the required heat quantity of feed stream 14.

[0045] As mentioned above, the heating zone 20, more specifically the electric heater 22, may be disposed between the two reactors 12. The electric heater 22 may be located at the inlet of the second heater 24, or at the outlet of the second heater 24, or both. The electric heater 22 may be in series and / or parallel with the second heater 24. The electric heater 22 may be disposed within the reactor 12 before the catalyst bed 16, such that the feed stream passes through the electric heater 22 before passing through the catalyst bed 16. The electric heater 22 may also be disposed after the catalyst bed 16 or between the catalyst beds 16.

[0046] 2 and 3, an electric heater 22 is shown having a heater bundle 30 with hairpin-shaped heating tubes or elements 32. It should be understood that multiple bundles 30 may be used. The hairpin-shaped heating tubes 32 may be up to 10 feet long, with a typical outer diameter of 0.43 inches. A single electric heater bundle 30 with a bundle diameter of 50 inches and an immersion length of 7 feet (heated length of 5 feet) can provide 1.8 MW of heat to the process (a temperature rise of 5.6°C (10°F) for a reactor steam flow of 633,000 lb / hr) at a pressure drop of 3.4 kPa (0.5 psi). Different bundle 30 diameters and lengths are possible to optimize performance and meet process requirements.

[0047] The electric heater bundle 30 may be installed in parallel flow above hairpin-shaped heater tubes 32 (FIG. 2), which provides the most uniform flow above all elements and eliminates flow maldistribution and corresponding high temperature areas within the bundle 30. The elbow in a typical transfer line can also be replaced with a T, and the electric heater bundle 30 can then be installed in the piping through the long section of the T. While FIG. 2 shows that the electric heater bundle and flow orientation can be horizontal, FIG. 3 shows that the bundle and flow orientation can be vertical. FIGS. 2 and 3 also show that the flow inlet (or outlet) can be located at either end of the electric heater bundle, allowing the bundle design to be optimized for the flow temperature.

[0048] It is also contemplated that the electric heater 22 may be located along the transfer line rather than at an elbow. For example, as shown in Figure 4, a hairpin-shaped heating tube may be installed in cross-flow across the bundle of electric heaters 22. This limits the length of the electric heater 22 tube and / or bundle based on the diameter of the transfer line, since the electric heater 22 tube and / or bundle will be perpendicular to the flow in the line (left to right or right to left in Figure 4).

[0049] Thus, the heating elements 32 may be parallel to one another in a horizontal ( FIG. 5 ) or vertical ( FIG. 6 ) orientation, or any orientation in between. It is further contemplated that combinations of orientations may be provided, such as a combination of vertical and horizontal orientations that provide a mesh-like pattern. It is further contemplated that the heating elements 32 may have the geometric shapes of FIG. 7 (such as hexagonal or spiral coils).

[0050] Suitable baffles or shrouds around the heating bundles are contemplated to maximize velocity above the bundles and eliminate maldistribution and hot zones in the bundles. Multiple bundles may be installed to achieve the desired heat load.

[0051] Longer electric heater bundles and multiple bundle installations can be used to reduce element temperatures, better eliminate fouling and coking, and improve design life. Electric heater design must carefully consider fluid temperature, element temperature, heat load, pressure drop, and the fouling / coking tendency of the process fluid.

[0052] The electric heater bundle may be located immediately upstream or immediately downstream of the fired heater, or both (this applies to charge heaters and / or interstage heaters). The electric heater provides the greatest advantage over the fired heater when it is downstream, because it reduces the fired heater outlet temperature, which can be used to optimize the fired heater design and save size. Additionally, the electric heater bundle may be located close to the reactor inlet to minimize the hot volume.

[0053] The heat load of the electric heater 22 can be controlled and monitored, for example, by flow temperature measurements and element temperature measurements. In addition to ensuring proper heating, such data can be used to protect the element from overheating and failure. Thus, a set level can be used to control the heat load to avoid overheating. Heat loss from the electric heater can be compensated for by a fired heater.

[0054] Additionally, the control of heat load may be control of multiple bundles, individual bundles, or groups of elements within a single bundle, selected to optimize performance and reliability of electric heater operation.

[0055] Electric heaters may be installed upstream of the fired heater based on layout needs and availability or to improve the electric heater design. The upstream location helps minimize element temperatures, better eliminate fouling and coking, and improve design life. Electric heater hairpin elements can also be placed around the inlet or outlet of the radial flow reactor. This placement eliminates space needs in the transfer lines and can further reduce high temperature residence time.

[0056] experiment A quick yield estimation was simulated in a reforming reactor where 50% of the hot volume from all transfer lines, heater manifolds, and heater tubes was operated at a temperature 20°F lower than the conventional design, while keeping all other parameters (i.e., reactor inlet temperature, pressure, etc.) the same. In addition to showing a reduction in carbon dioxide production, the simulation estimated an additional C5+ yield of 0.2 wt% over the current design.

[0057] A rapid thermal assessment of the combustion heater in the reforming process unit was performed, where heater performance was quantified / estimated by reducing the heater terminal temperature by 11°C (20°F). It was noted that such a reduction in heater terminal temperature resulted in a 20% reduction in fuel consumption, as well as a 20% reduction in carbon dioxide production.

[0058] Those skilled in the art should appreciate and understand that various other components, such as valves, pumps, filters, coolers, etc., are not shown in the drawings because their details are well within the knowledge of those skilled in the art and their description is not necessary to practice or understand embodiments of the present invention.

[0059] Any of the above lines, conduits, units, devices, vessels, ambient environments, zones, or the like may be equipped with one or more monitoring components, including sensors, measurement devices, data acquisition devices, or data transmission devices. Signals, process, or condition measurements and data from the monitoring components may be used to monitor conditions in, around, and on the process equipment. Signals, measurements, and / or data generated or recorded by the monitoring components may be collected, processed, and / or transmitted over one or more networks or connections, which may be private or public, general or specific, direct or indirect, wired or wireless, encrypted or unencrypted, and / or combinations thereof. This specification is not intended to be limiting in this respect.

[0060] Signals, measurements, and / or data generated or recorded by the monitoring components may be transmitted to one or more computing devices or systems. The computing devices or systems may include at least one processor and memory storing computer-readable instructions that, when executed by the at least one processor, cause the one or more computing devices to perform a process, which may include one or more steps. For example, the one or more computing devices may be configured to receive data related to at least one piece of equipment associated with the process from one or more monitoring components. The one or more computing devices or systems may be configured to analyze the data. Based on the analysis of the data, the one or more computing devices or systems may be configured to determine one or more recommended adjustments to one or more parameters of one or more processes described herein. The one or more computing devices or systems may be configured to transmit encrypted or unencrypted data including one or more recommended adjustments to one or more parameters of one or more processes described herein.

[0061] Specific Embodiments While the following will be described in conjunction with specific embodiments, it will be understood that this description is illustrative, but not intended to limit the scope of the preceding description and appended claims.

[0062] A first embodiment of the present invention is a chemical reaction process zone including at least one reaction zone having a reactor that receives a feed stream and causes a chemical reaction of components of the feed stream under suitable conditions; a heating zone configured to provide heat to the feed stream upstream of the at least one reaction zone, the heating zone including an electric heater configured to provide a first portion of a required amount of heat to the feed stream; and a second heater configured to provide a second portion of a required amount of heat to the feed stream, wherein the first and second portions achieve a minimum temperature, and the second heater is either a combustion heater or an electric heater. An embodiment of the present invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, wherein the at least one reaction zone includes two reactors, and the electric heater is disposed in a transfer line between the first reactor and the second reactor. An embodiment of the present invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, wherein the electric heater is disposed in a transfer line upstream of the second heater. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, in which the electric heater is located in the transfer line downstream of the second heater. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, in which the reactor comprises a catalyst bed and the electric heater is located inside the reactor before the catalyst bed. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, in which the reactor comprises a catalyst bed and the electric heater is located inside the reactor after the catalyst bed. An embodiment of the invention is one, any, or all of the previous embodiments to the first embodiment of this paragraph, in which the reactor comprises a first catalyst bed and a second catalyst bed and the electric heater is located inside the reactor, the electric heater being located after the first catalyst bed and before the second catalyst bed. An embodiment of the present invention is one, any, or all of the previous embodiment of this paragraph to the first embodiment of this paragraph, in which the first portion of the required heat amount is between 5% and 40% of the required heat amount.An embodiment of the present invention is one, any, or all of the previous embodiment through the first embodiment of this paragraph, in which the electric heater is installed at an elbow position of the transfer line and the feed stream flows parallel to the electric heater. An embodiment of the present invention is one, any, or all of the previous embodiment through the first embodiment of this paragraph, in which the electric heater is installed in the transfer line and the feed stream flows perpendicular to the electric heater. An embodiment of the present invention is one, any, or all of the previous embodiment through the first embodiment of this paragraph, in which the electric heater is disposed and installed in the transfer line in an arrangement configured to cover the entire cross section of the transfer line. An embodiment of the present invention is one, any, or all of the previous embodiment through the first embodiment of this paragraph, in which the second heater is a fired heater and the electric heater is disposed in series with the fired heater. An embodiment of the present invention is one, any, or all of the previous embodiment to the first embodiment of this paragraph, wherein the second heater is a combustion heater and the electric heater is disposed in parallel with the combustion heater.An embodiment of the present invention is one, any, or all of the previous embodiment to the first embodiment of this paragraph, further including a second electric heater disposed in series with the combustion heater.

[0063] A second embodiment of the present invention is a process for chemical reaction, the process comprising: heating a process stream with an electric heater; heating the process stream in a second heater, where the second heater is either a fired heater or an electric heater; passing the process stream through a reactor in a reaction zone whereby a chemical reaction of components of the feed stream occurs under suitable conditions; and recovering an effluent stream from the reactor. An embodiment of the present invention is one, any, or all of the previous through second embodiments of this paragraph, where the electric heater is upstream of the second heater. An embodiment of the present invention is one, any, or all of the previous through second embodiments of this paragraph, where the electric heater is downstream of the second heater. An embodiment of the present invention is one, any, or all of the previous through second embodiments of this paragraph, where the second heater is a fired heater and where the electric heater is disposed in series with the fired heater. An embodiment of the present invention is any one, any, or all of the preceding through second embodiments of this paragraph, in which the second heater is a fired heater and the electric heater is disposed in parallel with the fired heater. An embodiment of the present invention is any one, any, or all of the preceding through second embodiments of this paragraph, further comprising a second electric heater disposed in series with the fired heater. An embodiment of the present invention is any one, any, or all of the preceding through second embodiments of this paragraph, in which the electric heater provides 5% to 40% of the required heat for the chemical reaction. An embodiment of the present invention is any one, any, or all of the preceding through second embodiments of this paragraph, in which the process stream comprises effluent from an upstream reactor in the reaction zone.

[0064] Without further elaboration, it is believed that, using the preceding description, one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of the present invention, and can make various changes and modifications to the present invention to adapt it to various uses and conditions, without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0065] In the above, all temperatures are listed in degrees Celsius, and all parts and percentages are in "heat requirements" which are heat flow (eg, watts, Btu / hr) unless otherwise noted.

[0066] While at least one exemplary embodiment has been presented in the foregoing detailed description of the present invention, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment(s) are merely examples and are in no way intended to limit the scope, applicability, or configuration of the present invention. Rather, the foregoing detailed description provides those skilled in the art with a convenient guide for implementing exemplary embodiments of the present invention, and it should be understood that various changes can be made in the functions and arrangement of elements described in the exemplary embodiment without departing from the scope of the present invention as set forth in the appended claims and their legal equivalents.

Claims

1. A chemical reaction process zone (10) comprising: at least one reaction zone (11) having a reactor (12) for receiving a feed stream (14) and for effecting a chemical reaction of the components of said feed stream (14) under suitable conditions; a heating zone (20) configured to provide heat to the feed stream (22) upstream of the at least one reaction zone (11), an electric heater (22) configured to provide a first portion of the required heat quantity to the supply stream (14); and a heating zone (20) comprising a second heater (24) configured to provide a second portion of the required heat to the feed stream (14); wherein the first portion and the second portion achieve a minimum temperature, and the second heater is either a combustion heater or an electric heater.

2. 2. The chemical reaction process zone (10) of claim 1, wherein the at least one reaction zone (11) comprises two reactors (12), and the electric heater (22) is disposed in a transfer line between the first reactor (12) and the second reactor (12).

3. The chemical reaction process zone (10) of claim 1, wherein the electric heater (22) is disposed in the transfer line upstream of the second heater (24).

4. The chemical reaction process zone (10) of claim 1, wherein the electric heater (22) is disposed in the transfer line downstream of the second heater (24).

5. 2. The chemical reaction process zone (10) of claim 1, wherein the reactor includes a catalyst bed (16), and the electric heater (22) is located within the reactor (12), before the catalyst bed (16), or after the catalyst bed (16), or both.

6. The chemical reaction process zone (10) of any one of claims 1 to 5, wherein the first portion of the required heat quantity is between 5% and 40% of the required heat quantity.

7. 5. The chemical reaction process zone (10) of claim 1, wherein the electric heater (22) is installed at an elbow position in a transfer line, and the feed stream flows parallel to the electric heater (22).

8. The chemical reaction process zone (10) of any one of claims 1 to 4, wherein the electric heater (22) is installed in a transfer line and the feed stream flows perpendicular to the electric heater (22).

9. 6. The chemical reaction process zone (10) of any one of claims 1 to 5, wherein the second heater (24) is a fired heater, and the electric heater (22) is disposed in series with the fired heater, in parallel with the fired heater, or both.

10. 1. A process for producing a chemical reaction, comprising: heating the process stream (14) in an electric heater (22); heating the process stream (14) in a second heater (24), the second heater (24) being either a fired heater or an electric heater; passing said process stream (26) through a reactor (12) in a reaction zone (11) where chemical reaction of the components of said feed stream (14) occurs under suitable conditions; recovering an effluent stream (18) from said reactor (12); The process includes:

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