Method and apparatus for heating process fluid in heater

Abstract

The invention relates to a method and an apparatus for heating a process fluid with a heater having a burner. The fuel is passed to the combustor and combusted to produce heat. A stream of inert gas is provided to the combustor upstream or downstream or both of the combustor. The flow of the inert gas stream is controlled based on the composition of the fuel, where more inert gas passes downstream of the combustor as the amount of hydrogen in the fuel increases.

Description

Priority Statement

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 587,380, filed October 2, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates generally to methods and apparatus for heating process fluids in a heater, and more specifically to such heaters including a burner that receives hydrogen fuel. Background Technology

[0003] For a given furnace design (radiant coils, burners, conventional section design) and feed composition, there exists an optimal cross-temperature to produce the best maximum operating, yield, conversion, and efficiency. For example, steam cracker furnace designers, process licensors, and end users utilize computational yield models (cracking models, such as SPIRO from Technip Energies) to calculate yields. ® This is used to predict the optimal cross temperature and many other process variables that can be optimized to maximize yield and the conversion of alkanes to desired olefins (such as ethylene).

[0004] Maintaining optimal feed cross-temperatures—the temperature of the mixed steam from the convection zone to the radiation zone and the feed to the steam cracker—is crucial for achieving profitable steam cracker production. Simply put, too low a feed cross-temperature results in low conversion rates of alkanes to olefins, insufficient cracking, and low yields. Too high a feed cross-temperature leads to rapid coke buildup in the coils, resulting in short runs between decoking cycles. Decoking the cracker leads to downtime, lost production, and lost profits.

[0005] As process conditions change, the cracking model can be rerun to predict optimal variables. Changes in process conditions may include alterations to feedstock, such as changes to naphtha composition or ethane content in the feed gas, changes to fuel gas, excess combustion air, and atmospheric conditions.

[0006] For example, a change in fuel gas composition from 100% methane to 100% hydrogen will result in a reduction of approximately 19% in the mass flow rate through the furnace. While such an extreme change in mass flow rate may potentially occur, it is unlikely to happen in steam crackers, as steam crackers typically do not burn pure methane or natural gas. Steam crackers operating as process exhaust gas typically contain 30% to 90% hydrogen in their fuel gas. However, when entering 100% hydrogen combustion to achieve zero carbon emissions from burning any amount of hydrocarbon fuel, the mass flow rate will decrease. Furthermore, in other processes, the mass flow rate can decrease significantly. Without other process variables changing, where the combustion rate is constant, these reductions in mass flow rate can lead to a significant drop of several hundred degrees in cross temperatures, potentially halving the conversion rate of alkanes to olefins, halving productivity, and potentially rendering the operation unprofitable.

[0007] Therefore, it is desirable to provide systems and methods adapted to hydrogen fuels. Summary of the Invention

[0008] This invention utilizes an inert gas to provide mass flow and ensure desired burner and heater operation. It offers the benefit of being able to convert to a high-hydrogen, low-carbon emission fuel gas without suffering efficiency losses due to mass flow losses through convection sections. Furthermore, this invention adds an additional degree of freedom to independently optimize the system mass flow rate while optimizing nitrogen oxide emissions.

[0009] This invention addresses the problem of reduced mass flow rate through the convection section when a steam cracker operates with high-hydrogen-content fuels to reduce carbon emissions instead of burning conventional hydrocarbon-content fuel gases. The reduced mass flow rate through the furnace is due to hydrogen combustion, and for a given combustion rate in the radiant section (combustion chamber), it significantly reduces conductive heat transfer in the convection section. The convection section is sized to heat various streams (including water) to produce steam for the steam cracking process, steam for output, and to preheat alkanes before being injected into the radiant section (where the furnace tubes are used as an alkane-to-olefins conversion reactor for olefin production). Whether using a new unit or retrofitting, the convection section must be designed for the higher mass flow rates of hydrocarbon fuel combustion to allow the unit to operate flexibly to and from low-hydrogen combustion operations. This invention injects freely available nitrogen from an ATR or other inert gas source into the furnace system to restore and regulate the mass flow rate, thereby optimizing the efficiency of the convection section. Convection section efficiency can be measured by monitoring or predicting the process cross temperature as the reprocess fluid moves from the convection section to the radiative section. This invention provides operators, furnace designers, and process licensors with new degrees of freedom—adjusting system mass flow rates to optimize conventional section efficiency without adversely altering other variables, such as excess air and combustion rate.

[0010] Therefore, the invention may be characterized in at least one aspect by providing a method for heating a process fluid flow in a heater by: determining the composition of a fuel delivered to a burner of the heater, wherein the fuel is burned to generate heat, and wherein the composition of the fuel is hydrogen fuel, hydrocarbon fuel, or a mixture of hydrogen and hydrocarbon; determining a mass flow rate for the heater based on the composition of the fuel; and adjusting the flow rate of an inert gas flow to the heater based on the mass flow rate.

[0011] When the fuel composition is determined to contain hydrogen or a mixture of hydrogen and hydrocarbons, regulation may include increasing the flow rate of the inert gas stream.

[0012] Adjusting the flow rate of the inert gas stream may also include comparing the mass flow rate with the target mass flow rate.

[0013] An inert gas stream can be delivered to the burner. The inert gas stream can be mixed with the fuel before combustion.

[0014] An inert gas flow can be delivered to the combustion zone of the heater. The combustion zone is downstream of the burner. An inert gas flow can also be delivered to the burner upstream of the combustion zone.

[0015] The method may also include separating an oxygen stream from the air to provide an oxygen-deficient stream, which, together with the oxygen stream, generates hydrogen in a thermal reformer. The hydrogen can be a fuel, and the oxygen-deficient stream can be an inert gas stream.

[0016] On the other hand, the present invention can be broadly characterized as providing a method for heating a process fluid flow in a heater by: delivering a fuel flow to a burner of the heater, wherein the heater includes a radiant section having at least one conduit carrying the process fluid flow; burning fuel from the fuel flow in a combustion zone to generate a flame and heat; delivering an inert gas downstream of the flame to the combustion zone to provide heated, mass-enriched flue gas; and transferring heat from the heated, mass-enriched flue gas to the process fluid flow in the radiant section.

[0017] The heater may have a convection section disposed above the radiant section, and the radiant section may include at least one conduit carrying the process fluid. The method may also include transferring heat from heated, mass-enriched flue gas to the process fluid flow in a conventional section.

[0018] The method may further include delivering a portion of the inert gas to the burner. The portion of the inert gas delivered to the burner may be injected into the primary combustion zone. Additionally and / or alternatively, the portion of the inert gas delivered to the burner may be mixed with the fuel stream. Additionally and / or alternatively, a portion of the inert gas delivered to the burner may be injected into the secondary combustion zone.

[0019] The method may also include passing an air stream to a separation zone configured to provide an oxygen stream and an oxygen-deficient stream; passing an oxygen stream to a thermal reformer configured to provide a hydrogen stream under appropriate conditions; passing a hydrogen stream as a fuel stream to a burner; and passing an oxygen-deficient stream as an inert gas to a combustion zone.

[0020] The method may further include determining the amount of hydrogen in the fuel stream and adjusting the flow rate of the inert gas based on the amount of hydrogen. The method may include determining a mass flow rate based on the amount of hydrogen and comparing the mass flow rate with a target mass flow rate. Adjustment of the inert gas flow rate may be based on the difference between the mass flow rate and the target mass flow rate.

[0021] On the other hand, the present invention provides an apparatus for heating a process fluid flow. The apparatus may include: a heater having a burner in a radiant section having at least one conduit carrying the process fluid flow; a burner configured to receive a fuel flow and burn the fuel flow in a combustion zone to generate a flame and heat; and a pipeline configured to deliver an inert gas to a combustion zone downstream of the flame to provide heated, mass-enriched flue gas.

[0022] The device may also include a second pipeline configured to supply part of an inert gas to the combustion zone.

[0023] The device may also include: a controller configured to determine the composition of the fuel flow; and a valve configured to regulate the flow rate of inert gas in the pipeline.

[0024] Further aspects, embodiments, and details of the invention (all of which may be combined in any way) are set forth in the following detailed description of the invention. Attached Figure Description

[0025] One or more exemplary embodiments of the present invention will now be described with reference to the following accompanying drawings, wherein:

[0026] Figure 1 A schematic diagram of an apparatus for implementing a process according to one or more embodiments is shown. Detailed Implementation

[0027] As described above, methods and apparatus for heating process flows have been invented. This invention maintains optimal cross-temperatures by injecting an inert gas (such as nitrogen or other readily available suitable gas) into the burner and furnace combustion chamber when the hydrogen content of the fuel changes, thereby maintaining optimal mass flow rates in the furnace system.

[0028] While a mixed-feed steam cracker is conceived as a preferred embodiment, the present invention is applicable to any type of steam cracker, including ethane or propane feed units (gas crackers), naphtha feed units (liquid crackers), or naphtha-to-ethane and propane (NEP) units (steam cracker furnaces and Oleflex). ® (Board heaters). And although the invention is envisioned for application in steam cracking processes, it can be applied to any other process utilizing flame heaters and furnaces.

[0029] In some steam cracking units, automated thermal reforming (ATR) is being considered or actively implemented. For ATR, an air separator is present that separates oxygen from atmospheric air and delivers it to the ATR for hydrogen production. Simultaneously, the ATR produces a significant amount of nitrogen as a byproduct (from the air separator). While some attempts have been made to efficiently utilize the nitrogen byproduct from the air separator unit, most in large-scale ATR use simply release it into the atmosphere to generate enough hydrogen to ignite the steam cracker assembly. This invention allows for the utilization of this gas stream.

[0030] While the present invention envisions utilizing a large quantity of nitrogen from an air separator on the ATR, other nitrogen sources in the processing plant can be obtained from other air separators or other process sources. Furthermore, the processing plant may have other available gas streams that can be suitably utilized in the present invention, such as steam, flue gas, FCC unit exhaust gas, or even carbon dioxide, in place of or in combination with nitrogen.

[0031] It is anticipated that furnace design and yield modeling can be performed and optimized during the project design phase. However, by continuously running the yield model as a real-time digital twin to the operating furnace, the nitrogen injection rate can be continuously calculated and modulated to maintain the optimal mass flow rate through the burner and furnace system in response to changes in fuel gas composition, feedstock composition, atmospheric conditions, etc.

[0032] Continuous optimization of nitrogen injection provides optimization freedoms not currently available in existing furnace systems. In existing systems, operation can be primarily regulated by altering excess air and operating at suboptimal excess air levels, resulting in wasted fuel gas. This invention can produce productivity, yield, and uptime exceeding those designed for current systems. Therefore, achieving net-zero ethylene production using 100% hydrogen combustion according to this invention may be a more efficient olefin production method than conventional prior art.

[0033] On demand, the targeted injection of nitrogen (or other inert gases) into one or more locations within the burner can reduce NOx emissions to single-digit ppm levels, thereby eliminating the need for selective catalytic reduction systems or significantly reducing their size.

[0034] In view of these general principles, one or more embodiments of the invention will be described in accordance with the following description, which is not intended to be limiting.

[0035] refer to Figure 1 The device 10 for heating one or more process fluid flows includes a heater 12, such as a furnace, which includes one or more burners 14. While any particular burner can be used, an exemplary low-NOx burner is described in U.S. Patent No. 11,649,960.

[0036] The heater 12 has a radiant section 16 that includes one or more conduits 18 containing process fluid. Multiple conduits 18 may be used, and each conduit may contain a different process fluid to be heated. Above the radiant section 16 is typically a convection section 20, which also includes one or more conduits 18 containing process fluid. As is known, in the radiant section 16, heat is transferred from the flame to the process fluid, and in the convection section 20, heat is transferred from hot flue gas to the process fluid.

[0037] Each burner 14 receives a fuel stream 22, which is delivered to a combustion zone 24 within the heater 12 and generates flame and heat. Each burner 14 also typically receives a combustion air stream 26 that can be mixed with the fuel stream 22 (or a portion thereof).

[0038] As discussed at the outset, the fuel to burner 14 can be hydrogen, hydrocarbons, or mixtures thereof with different hydrogen-to-hydrogen ratios. Although there is a growing trend to utilize more and more hydrogen to reduce environmental impact, the mass flow rate of flue gas from radiant section 16 to convection section 20 is reduced based on the amount of hydrogen in the fuel.

[0039] Therefore, the present invention includes a conduit 28 configured to deliver an inert gas to a combustion zone 24 downstream of the flame to provide heated, mass-enriched flue gas. An inert gas is a gas that comprises compounds and does not burn or otherwise undergoes a chemical change in the combustion zone 24. Examples of inert gases include nitrogen, steam from, for example, a boiler or steam generator, flue gas from, for example, a heater or boiler exhaust, PSA exhaust gas, FCC exhaust gas, FCC exhaust gas, carbon dioxide, and combinations thereof.

[0040] Furthermore, the device is further anticipated to include a second line 30 that supplies an inert gas flow to the combustion zone 24 via a feed to the burner 14. This can be used to reduce NOx emissions from the flame by decreasing the available oxygen content in the combustion zone 24. The inert gas from line 30 can be supplied to the primary combustion zone or the secondary combustion zone, or both, depending on the burner design.

[0041] While the ability to increase mass flow rate has been improved, there is also a desire to provide the ability to regulate different fuel compositions, from pure hydrogen to pure hydrocarbons, and various mixtures between them.

[0042] Therefore, controller 32 can be in communication with one or more valves 34 located in the pipelines 28, 30 carrying the inert gas. Controller 32 can receive signals or other information related to the composition of the fuel. For example, sensor 36 may be located in the pipeline carrying the fuel flow 22. Alternatively or additionally, the composition may be input or based on other information received from, for example, another controller / computer associated with the processing unit providing the fuel flow 22.

[0043] The controller 32 can then determine the composition of the fuel and, based on the determined composition, determine the mass flow rate. The controller 32 can then send or transmit a signal that causes the valve 34 to regulate the flow rate of the inert gas in line 28 and / or line 30. For example, when the fuel is determined to be almost entirely hydrocarbons, the controller 32 can regulate the valve 34 such that almost all (if not all) of the inert gas is delivered to the burner 14. When the fuel is determined to have a higher amount of hydrogen, the flow rate of the inert gas to the radiant section 16 (in line 28 and / or line 30) can be increased. Therefore, it should be understood that all inert gas can be delivered to the burner 14, or all inert gas can be delivered to the radiant section 16, or the inert gas can be diverted at any ratio between the two.

[0044] Mass flow rate determination can be performed continuously or intermittently. Additionally, controller 32 may include a memory that stores a lookup table of the target mass flow rate based on various variables of heater 12 and the processing unit receiving process fluid in conduit 18. Alternatively, controller 32 may determine the target mass flow rate based on received information. Commands sent by controller 32 may be for adjusting conditions, particularly, but not exclusively, adjusting the conditions of the inert gas in line 28 and / or line 30.

[0045] Therefore, those skilled in the art should recognize and understand that various other components connected to the controller 32, such as valves, pumps, filters, coolers, etc., are not shown in the drawings, because it is believed that their specific contents are entirely within the knowledge of those skilled in the art and their description is not necessary for the implementation or understanding of the embodiments of the present invention.

[0046] exist Figure 1 The text further illustrates specific implementation schemes, and these specific implementation schemes will be described with the understanding that they are not intended to be limiting.

[0047] As depicted, airflow 50 is passed to separation zone 52, which is configured to separate its components and provide oxygen flow 54 and oxygen-lean flow 56. Oxygen flow 54 can be passed to thermal reformer zone 57, which is configured to provide hydrogen flow 58 from the effluent of the reaction of oxygen with methane and water or carbon dioxide under appropriate conditions. Hydrogen flow 58 can be passed to combustor 14 as fuel flow 22. To increase the mass flow rate based on hydrogen fuel, oxygen-lean flow 56 can be used as inert gas 28 and passed to radiant section 16 / combustion zone 24 and / or combustor 14.

[0048] The systems and devices described herein may include a controller 32 or a computing device including processing and memory storing computer-executable instructions for implementing the processes described herein. The processing unit may include any suitable device configured to cause a series of steps to be performed to implement the method, such that the instructions, when executed by a computing device or other programmable means, cause the functions / actions / steps specified in the methods described herein to be performed. The processing unit may include, for example, any type of general-purpose microprocessor or microcontroller, digital signal processing (DSP) processor, central processing unit (CPU), integrated circuit, field-programmable gate array (FPGA), reconfigurable processor, other suitable programmable or programmable logic circuitry, or any combination thereof.

[0049] Memory can be any suitable known or other machine-readable storage medium. Memory can include non-transitory computer-readable storage media, such as, but not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or any suitable combination thereof. Memory can include any suitable combination of computer memories, whether internal or external to a device, such as random access memory (RAM), read-only memory (ROM), optical disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferroelectric RAM (FRAM), etc. Memory can include any storage device (e.g., a device) adapted to store computer-executable instructions executable by a processing unit in a retrievable manner.

[0050] The methods and systems described herein may be implemented using high-level programs or object-oriented programming or scripting languages, or combinations thereof, to communicate with or assist the operation of a controller or computing device. Alternatively, the methods and systems described herein may be implemented using assembly or machine language. The language may be a compiled or interpreted language. Program code used to implement the methods and systems described herein may be stored on a storage medium or device, such as ROM, disk, optical disk, flash drive, or any other suitable storage medium or device. The program code may be general-purpose or special-purpose programmable computer-readable, used to configure and operate the computer when the storage medium or device is read by a computer to perform the processes described herein.

[0051] Computer-executable instructions can take many forms, including modules, and can be executed by one or more computers or other devices. Generally, a module includes routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. Typically, the functionality of a module can be combined or distributed according to the needs of various implementation schemes.

[0052] It should be understood that systems and devices and their components may communicate via any of a variety of network protocols (such as TCP / IP, Ethernet, FTP, HTTP, etc.) and / or via a variety of wireless communication technologies (such as GSM, CDMA, Wi-Fi, and WiMAX), and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

[0053] Specific implementation plan

[0054] While the following description is presented in conjunction with specific embodiments, it should be understood that the description is intended to be illustrative and not to limit the scope of the foregoing description and the appended claims.

[0055] A first embodiment of the present invention is a method for heating a process fluid flow in a heater, the method comprising: determining the composition of fuel delivered to a burner of the heater, wherein the fuel is burned to generate heat, and wherein the composition of the fuel is hydrogen fuel, hydrocarbon fuel, or a mixture of hydrogen and hydrocarbons; determining a mass flow rate for the heater based on the fuel composition; and adjusting the flow rate of an inert gas flow to the heater based on the mass flow rate. An embodiment of the present invention is one, any, or all of the embodiments preceding this paragraph to the first embodiment of this paragraph, wherein when the fuel composition is determined to contain hydrogen or a mixture of hydrogen and hydrocarbons, the adjustment includes increasing the flow rate of the inert gas flow. An embodiment of the present invention is one, any, or all of the embodiments preceding this paragraph to the first embodiment of this paragraph, wherein adjusting the flow rate of the inert gas flow includes comparing the mass flow rate with a target mass flow rate. An embodiment of the present invention is one, any, or all of the embodiments preceding this paragraph to the first embodiment of this paragraph, wherein the inert gas flow is delivered to the burner. One embodiment of the invention is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, wherein the inert gas stream is mixed with fuel prior to combustion. One embodiment of the invention is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, wherein the inert gas stream is delivered to a combustion zone of a heater downstream of a burner. One embodiment of the invention is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, wherein the inert gas stream is also delivered to a burner upstream of the combustion zone. One embodiment of the invention is one, any, or all of the embodiments described in the preceding embodiments to the first embodiment of this paragraph, further comprising separating an oxygen stream from air to provide an oxygen-lean stream; utilizing the oxygen stream in a thermal reformer to generate hydrogen, wherein the hydrogen is fuel, and wherein the oxygen-lean stream is an inert gas stream.

[0056] A second embodiment of the invention is a method for heating a process fluid flow in a heater, the method comprising: delivering a fuel flow to a burner of the heater, wherein the heater includes a radiant section having at least one conduit carrying the process fluid flow; burning fuel from the fuel flow in a combustion zone to generate a flame and heat; delivering an inert gas downstream of the flame into the combustion zone to provide heated, mass-enriched flue gas; and transferring heat from the heated, mass-enriched flue gas to the process fluid flow in the radiant section. One embodiment of the invention is one, any, or all of the embodiments described in the preceding embodiments to the second embodiment of this section, wherein the heater includes a convection section disposed above the radiant section, wherein the radiant section includes at least one conduit carrying the process fluid, and wherein the method further includes transferring heat from the heated, mass-enriched flue gas to the process fluid flow in the convection section. Another embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this section, the embodiment further including delivering a portion of the inert gas to the burner. One embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, wherein a portion of the inert gas delivered to the burner is injected into the primary combustion zone. Another embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, wherein a portion of the inert gas delivered to the burner is mixed with the fuel stream. Another embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, wherein a portion of the inert gas delivered to the burner is injected into the secondary combustion zone. Another embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, further comprising: delivering an air stream to a separation zone configured to provide an oxygen stream and an oxygen-lean stream; delivering an oxygen stream to a thermal reformer configured to provide a hydrogen stream under suitable conditions; delivering a hydrogen stream as a fuel stream to the burner; and delivering an oxygen-lean stream as an inert gas to the combustion zone. One embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, and this embodiment further includes: determining the amount of hydrogen in the fuel stream; and adjusting the flow rate of the inert gas based on the amount of hydrogen. Another embodiment of the invention is one, any, or all of the embodiments described in the second embodiment to the preceding embodiments of this paragraph, and this embodiment further includes: determining a mass flow rate based on the amount of hydrogen; and comparing the mass flow rate with a target mass flow rate, wherein the adjustment of the inert gas flow rate is based on the difference between the mass flow rate and the target mass flow rate.

[0057] A third embodiment of the invention is an apparatus for heating a process fluid flow, the apparatus comprising: a heater having a burner in a radiant section, the radiant section including at least one conduit carrying the process fluid flow; a burner configured to receive a fuel flow and burn the fuel flow in a combustion zone to generate a flame and heat; and a line configured to deliver inert gas downstream of the flame into the combustion zone to provide heated, mass-enriched flue gas. One embodiment of the invention is one, any, or all of the third embodiment to the preceding embodiments of this paragraph, further comprising: a second line configured to provide a portion of the inert gas to the combustion zone. Another embodiment of the invention is one, any, or all of the third embodiment to the preceding embodiments of this paragraph, further comprising: a controller configured to determine the composition of the fuel flow; and a valve configured to regulate the flow rate of the inert gas in the line.

[0058] Although no further detailed description has been provided, it is believed that those skilled in the art will be able to make full use of the invention by employing the foregoing description and will be able to readily identify the essential features of the invention without departing from its spirit and scope, and to make various changes and modifications to adapt it to various uses and situations. Therefore, the foregoing preferred embodiments should be understood as illustrative only and not as limiting the remainder of this disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0059] In the foregoing, all temperatures are expressed in degrees Celsius, and all portions and percentages are by weight unless otherwise specified.

[0060] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be understood that numerous variations exist. It should also be understood that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or construction of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing exemplary embodiments of the invention, and it should be understood that various changes can be made to the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.

Claims

1. A method for heating a process fluid flow in a heater (12), the method comprising: Determine the composition of the fuel (22) delivered to the burner (14) of the heater (12), wherein the fuel is burned to generate heat, and wherein the composition of the fuel (22) is hydrogen fuel, hydrocarbon fuel, or a mixture of hydrogen and hydrocarbon. The mass flow rate for the heater (12) is determined based on the composition of the fuel (22); and The flow rate of the inert gas flow (28) to the heater (12) is adjusted based on the mass flow rate.

2. The method of claim 1, wherein when it is determined that the fuel composition (22) contains hydrogen or a mixture of hydrogen and hydrocarbons, the adjustment includes increasing the flow rate of the inert gas stream (28).

3. The method according to claim 1, wherein adjusting the flow rate of the inert gas flow (28) comprises: The mass flow rate is compared with the target mass flow rate.

4. The method according to any one of claims 1 to 3, wherein the inert gas stream (28) is delivered to the burner (14).

5. The method according to claim 4, wherein the inert gas stream (28) is mixed with the fuel prior to combustion.

6. The method according to any one of claims 1 to 3, wherein the inert gas flow (28) is delivered to the combustion zone (24) of the heater (12), the combustion zone (24) being downstream of the burner (14).

7. The method according to claim 6, wherein the inert gas flow (22) is also delivered to the burner (14) upstream of the combustion zone (24).

8. The method according to any one of claims 1 to 3, further comprising: Oxygen stream (54) is separated from air (50) to provide oxygen-deficient stream (56). Hydrogen (58) is generated in the thermal reformer (57) using the oxygen stream (54). The hydrogen (58) therein is the fuel (22), and The oxygen-deficient flow (54) is the inert gas flow (28).

9. An apparatus (10) for heating a process fluid flow, the apparatus comprising: Heater (12), the heater having a burner (14) in a radiant section (16), the radiant section (16) including at least one conduit (18) having a process fluid flow. The burner (14) is configured to receive the fuel stream (22) and burn the fuel stream (22) in the combustion zone (24) to generate flame and heat; A pipeline (28) is configured to deliver inert gas downstream of the flame into the combustion zone (24) to provide heated, mass-enriched flue gas.

10. The device (10) according to claim 9, further comprising: A second pipeline (30) is configured to supply a portion of the inert gas to the combustion zone (24).

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