Steam cracking furnace and method

Abstract

The present disclosure provides a method and apparatus for cracking a hydrocarbon-containing feed. The method includes introducing the hydrocarbon-containing feed to a desalter preheater train having an effluent exchanger. The method includes directing a portion of the hydrocarbon-containing feed from the desalter preheater train to a feed inlet of a convection section of a steam cracking furnace. The method includes combusting fuel in the vicinity of a plurality of burners that provide thermal energy to a radiant section and the convection section of the steam cracking furnace. The hydrocarbon-containing feed is in an operating mode in the convection section to obtain a heated feed mixture. The method includes separating a bottoms effluent from the heated feed mixture of the convection section in a separator. The method includes cooling the bottoms effluent using boiler feed water in a heat exchanger.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to U.S. Provisional Application No. 63 / 290,301, filed on December 16, 2021, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The implementation schemes of this disclosure generally relate to methods and systems for cracking hydrocarbons. Specifically, this disclosure relates to managing furnace temperatures to allow for flexible use of hydrocarbon feedstocks and operating conditions. Background Technology

[0004] Steam cracking (also known as pyrolysis) is a commercial method for producing light olefins, particularly ethylene and propylene. In a typical steam cracking process, the hydrocarbon feed is first preheated and mixed with dilution steam in the convection section of the furnace. After preheating in the convection section, the steam feed / dilution steam mixture is rapidly heated in the radiant section to achieve thermal cracking of the hydrocarbons. After a predetermined amount of thermal cracking has occurred, the furnace effluent is rapidly quenched either in an indirect heat exchanger or by direct injection of a quench feed stream.

[0005] Byproducts of cracking include carbon deposits, termed "coke," on the inner surfaces of the furnace's radiant tubes. Depending on the hydrocarbon feedstock, coke may also deposit in certain tubes in the convection section or in the furnace's quench system. Decoking operations affect cracking flux, and increasing the time between decoking operations is a goal of cracking processes. Increasing the time between decoking operations by preventing coke accumulation and improving hydrocarbon conversion involves selective and controlled heating and cooling of portions of the steam cracker. Controlled heating typically utilizes a significant amount of energy from the furnace, at least partially released from it. Furthermore, steam crackers operate under different conditions depending on the type of feedstock, processing rate, scaling rate, and environment. The furnace needs to be flexible enough to handle different ultra-high pressure or high pressure steam rates and different flue gas rates for varying convective loads.

[0006] Therefore, it is necessary to minimize energy loss in high-efficiency furnaces, effectively promote hydrocarbon conversion, and reduce the stack temperature of various feeds. Summary of the Invention

[0007] In at least one embodiment, the steam cracking method includes introducing a hydrocarbon-containing feed into a desalter preheater unit including an effluent exchanger. The method includes directing at least a portion of the hydrocarbon-containing feed from the desalter preheater unit to the feed inlet of the convection section of a steam cracker. The method includes burning fuel at multiple burners to provide heat to the radiant section and the convection section of the steam cracker. The method includes heating the hydrocarbon-containing feed in the convection section in operating mode to obtain a heated feed mixture. The method includes separating the bottom effluent from the heated feed mixture in the convection section in a separator. The method includes cooling the bottom effluent using boiler feed water in a heat exchanger.

[0008] In at least one embodiment, the equipment includes a steam cracker comprising a convection section and a radiant section. A desalter preheater unit is connected to the feed inlet of the convection section of the steam cracker. The desalter preheater unit includes an effluent exchanger, a temperature-controlled preheater in fluid communication with the effluent exchanger, and at least one desalter in fluid communication with the temperature-controlled heater. At least one desalter is in fluid communication with the effluent exchanger, and multiple burners are disposed within the steam cracker and are capable of supplying heat energy to the steam cracker by burning fuel.

[0009] In at least one embodiment, the steam cracking method includes introducing a hydrocarbon-containing feed directly from a hydrocarbon feed tank into a desalter preheater unit. The method includes separating a first portion and a second portion of the hydrocarbon-containing feed in the desalter preheater unit. Separation includes introducing the hydrocarbon-containing feed into an effluent exchanger. The method includes preheating the hydrocarbon-containing feed (from the effluent exchanger) in a temperature-controlled preheater in fluid communication with the effluent exchanger. The method includes separating a first portion and a second portion of the preheated effluent from the temperature-controlled preheater in at least one desalter in fluid communication with a temperature-controlled heater. At least one desalter is in fluid communication with the effluent exchanger. The method includes introducing a first portion of the preheated effluent into the effluent exchanger. The method includes guiding the first portion of the preheated effluent from the desalter preheater unit to the feed inlet of the convection section of a steam cracker. The method includes burning fuel at multiple burners to provide heat to the radiant section and the convection section of the steam cracker.

[0010] Brief description of the attached figures

[0011] To gain a more detailed understanding of the above-described features of this disclosure, a more specific description of the disclosure, which has been briefly outlined above, can be obtained by referring to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings are merely illustrative of exemplary embodiments and are therefore not intended to limit its scope; other equally effective embodiments may be recognized.

[0012] Figure 1 Describes an apparatus for processing hydrocarbons according to one embodiment.

[0013] Figure 2 A schematic flowchart describing a desalination unit configuration according to one embodiment.

[0014] Figure 3 A flowchart describing an example method for processing hydrocarbons according to one implementation scheme.

[0015] To facilitate understanding, the same reference numerals are used where possible to denote common elements in the figures. This covers elements and features of one embodiment that can be beneficially incorporated into other embodiments without further description.

[0016] Detailed description

[0017] This disclosure provides methods and systems for flexible, sustainable, and efficient cracking of hydrocarbons. Specifically, this disclosure provides methods and systems for managing furnace temperatures for flexible hydrocarbon feed and operating conditions. The hydrocarbon pyrolysis reactor (or furnace) of the methods and systems of this disclosure may include a convection section and a radiant section. As used herein, a convection section may be a portion of the furnace in which the hydrocarbon feed can be processed by convection heating. For example, as used herein, convection heating may be indirect heat exchange from hot flue gas from the radiant section in a channel (e.g., a metal tube assembly) having a thermally conductive surface. The convection section may include one or more convection zones, each having an inlet into the convection section and an outlet out of the convection section. The convection section may include one or more heating zones, as well as a preheating zone, which preheats the hydrocarbon feed using heated bottom material from a gas-liquid separator in a heat exchanger. Each convection section may be connected to a tube assembly for heat exchange. As used herein, the terms “downstream” and “upstream” refer to relative positions along the furnace in the direction of hydrocarbon and / or water / steam flow through the pipes, but (e.g., as...) Figure 1 (As shown in the diagram) This term does not require hydrocarbons and / or water / steam to flow through a single continuous pipe. As used herein, “boiler feed water” (BFW) refers to water that has been treated and degassed to be suitable for reliably generating steam at high pressure. For boiler water at pressures of about 50 bar or higher, the BFW is subjected to the removal of minerals, resulting in minimal conductivity and trace amounts of various boiler scale deposits. The BFW is often degassed with steam to remove trace amounts of oxygen that can rapidly corrode the boiler. The degassed method exposes the boiler feed water to temperatures of about 110°C to about 125°C and pressures above the desired steam pressure (e.g., for 100 bar steam, the BFW is often about 120 to about 150 bar).

[0018] Conventional furnaces are effective for cracking certain hydrocarbons (e.g., gas oil and naphtha). The economics of steam cracking sometimes favor the cracking of other types of hydrocarbons, such as low-cost feedstocks containing heavy hydrocarbons, like crude oil or atmospheric residues (e.g., atmospheric tubular furnace bottom stock). Heavy feedstocks may contain non-volatile components that can cause coke buildup within the furnace. Hydrocarbon feedstocks containing non-volatile components of crude oil are sometimes referred to herein as “crude oil feedstocks.” Therefore, suitable hydrocarbon feedstocks for the methods and systems of this disclosure include those feedstocks that contain crude oil, consist substantially of crude oil, or consist of crude oil. “Crude oil” or “raw oil” can be used interchangeably to mean a hydrocarbon composition suitable for use as feedstock in a crude oil refinery.

[0019] It has been found that arranging furnace service components can improve flexibility for using a wide range of hydrocarbons, from light to heavy hydrocarbons. As used herein, “service component” refers to one or more furnace components, such as piping arrangements, water boilers, boiler feed water energy-saving devices, steam generators, steam superheaters, steam superheat separators, or other components configured to exchange energy with each other and / or with parts of the furnace. As used herein, “flexibility” refers to the ability of the same furnace to process different types of hydrocarbon feeds in one or more operating modes, such as simultaneously maintaining operation within certain process and environmental constraints. The ability to process different types of hydrocarbon feeds at different processing rates or with varying degrees of severity can be determined by the availability and economics of the hydrocarbon feeds. Complementing to the processing of different hydrocarbon types, flexibility also includes the ability to change operating modes for cracking and decoking methods. Furthermore, sustainability goals for improving the overall energy efficiency of various hydrocarbon feeds have been considered in furnace design and configuration. Some furnaces have improved operational flexibility; however, flexibility can come at the expense of energy efficiency. Specifically, the flexibility allows for different ultra-high pressure (SHP) (e.g., about 100 bar or higher) or high pressure (HP) (e.g., about 30 bar or higher, or about 30 to about 50 bar) steam rates and different flue gas rates for different convective loads. Under certain operating conditions, the flue gas temperature can be increased to high temperatures, such as about 100°C or higher, or even about 150°C or higher. It has been found that low flue gas temperatures for high-efficiency furnaces can be achieved by using one or more of the methods described in this disclosure to provide cryogenic service components to the upward convection section, such as about 125°C or lower. As used herein, the term "flue gas temperature" refers to the temperature of the flue gas released from the furnace above the furnace inlet after passing through the furnace's convection section.

[0020] In some embodiments, the desalter arrangement provides a hydrocarbon feed and effluent exchanger for preheating the hydrocarbon feed before preheating the hydrocarbon feed, and / or provides a hydrocarbon feed and effluent exchanger before supplying the effluent to the furnace. The desalter preheating configuration of this disclosure provides reduced furnace feed temperature, reduced sprayer water injection (which enables separation of feed components from the hydrocarbon feed for improved energy efficiency), and reduced fresh water consumption. In some embodiments, the effluent exchanger cools the desalted effluent while heating the incoming hydrocarbon feed. The desalter operates at a temperature higher than the temperature of the hydrocarbon feed fed into the furnace. Since high temperatures are required between the two steps at the lower temperature (the tank at a colder temperature and the furnace feed at a colder temperature), it is reasonable to exchange heat between the feed and effluent using a temperature-controlled heater.

[0021] Another approach may involve changing the bottom material cooling surface from feed preheating to another service component, such as ultra-high pressure boiler feed water preheating or medium-pressure steam (e.g., about 7 bar to about 17 bar) generation, to maintain the low feed temperature in the upper convection section. As used herein, "boiler" is distinct from a transfer line exchanger that also boils ultra-high pressure steam. The "boiler" of this disclosure preheats ultra-high pressure boiler feed water, enabling it to capture energy benefits without incurring boiler energy deficits or flexibility limitations. Another approach provided herein may involve changing the heat from boiler effluent steam cooler and first-stage bottom material pump circulation from SHP boiler feed water preheating to low-temperature service components, such as ultra-high pressure boiler feed water preheating, medium-pressure steam generation, and / or high-pressure steam generation, to maintain the low SHP boiler feed water temperature in the upper convection section.

[0022] The terms “conversion,” “transformed,” “cracking,” and “cracked” are broadly defined herein to include any suitable molecular decomposition, splitting, conversion, dehydrogenation, and / or reforming of hydrocarbons or other organic molecules by means of at least pyrolysis, and may optionally include one or more of the following methods: catalysis, hydrogenation, diluents, stripping agents, and / or related methods.

[0023] Hydrocarbon feedstocks that can be processed using the methods and systems described herein may include recirculated gases such as ethane, steam cracked oil / residue blends, gas oil, heating oil, jet fuel, diesel, kerosene, gasoline, coking naphtha, steam cracked naphtha, catalytic cracked naphtha, hydrocracking oil, reformate, residual liquid reformate, Fischer-Tropsch synthesis liquid, Fischer-Tropsch synthesis gas, natural gasoline, distillates, crude oil such as heavy crude oil, light straight-run naphtha (LVN), atmospheric tubular furnace bottoms, vacuum tubular furnace feed streams including bottoms, wide-boiling-range naphtha-gas oil condensate, heavy non-straight-run hydrocarbon feed streams from refineries, vacuum gas oil, heavy gas oil, crude oil-contaminated naphtha, atmospheric residue, heavy residue, hydrocarbon / residue blends, hydrogen / residue blends, liquefied petroleum gas (LPG), and mixtures thereof.

[0024] Unless otherwise stated, all percentages, parts, ratios, etc., are by weight. Unless otherwise stated, references to a compound or component include the compound or component itself, and / or compounds or components in combination with other compounds or components, such as mixtures of compounds. Furthermore, when amounts, concentrations, or other values ​​or parameters are given as a list of upper and lower limits, this should be understood as specifically disclosing all ranges formed by any pair of upper and lower limits, whether or not such ranges are disclosed individually.

[0025] Figure 1 The apparatus 100 is described in accordance with some aspects of this disclosure. Heating of the hydrocarbon feed 131 can be achieved in any suitable manner, for example by means of... Figure 1 The hydrocarbon-containing feed in the convection section 103 of the furnace 101 shown is heated by indirect contact with the convection section 103. The convection section 103 may include a first preheating region 105 having first and second sets of convection tubes 115, 117. The first set of convection tubes 115 may be located in a first preheating section 107 of the first preheating region 105, and the second set of convection tubes 117 may be located in a second preheating section 109 of the first preheating region 105, substantially adjacent to the first set of convection tubes 115. The hydrocarbon-containing feed disposed in line 131 may be fed into the first set of convection tubes 115 and heated by convection with hot flue gas from line 112 of the radiant section 113, which passes through the convection section 103 and through each set of convection tubes (e.g., 115, 117). The hydrocarbon feed at the inlet of convection pipe 115 of the first group can have a temperature of about 20°C to about 300°C, for example about 25°C to about 250°C, for example about 25°C to about 100°C, for example about 32°C to about 65°C, or 150°C to about 250°C (e.g., in some crude oil applications), and / or a pressure of about 790 kPa to about 1825 kPa, for example about 800 kPa to about 1800 kPa, for example about 800 kPa to about 1000 kPa, or about 1000 kPa to about 1800 kPa. In some embodiments, an ammonia injection grid system (AIG) 181 is located between the second preheating section 109 and the superheater convection section 120. AIG 181 injects ammonia into the flue gas in a uniform distribution, allowing the ammonia in the flue gas to react with nitrogen oxides in the flue gas to remove nitrogen oxides. Without being bound by theory, it is believed that excessively high AIG temperatures allow ammonia to be oxidized to nitrogen oxides. It has been found that maintaining the temperature below the predetermined temperature can maintain an appropriate ammonia concentration that can be used for the reaction.

[0026] As those skilled in the art will appreciate, in commercial operation, one or more (e.g., each) of a tube bank may have multiple parallel flow tube systems within the furnace, rather than just a single tube, as described, for example, in U.S. Patent No. 3,365,387, which is incorporated herein by reference. Thus, any one or more flow paths can be isolated by appropriate valve control, thereby allowing decoking cycles to be run on one or more selected stopped pipe flow paths without interfering with the overall hydrocarbon pyrolysis process in the remaining operating tubes. Individual tube banks can be isolated, as disclosed in U.S. Patent No. 8,864,977, which is incorporated herein by reference.

[0027] In some embodiments, a selective catalytic reduction (SCR) bed 180 for reducing nitrogen oxides is disposed between a first preheating section 107 and a second preheating section 109. In some embodiments, the steam cracker includes a convection section 103 and a radiant section 113 downstream of the convection section 103. The convection section 103 includes a first heat exchanger 114 in fluid communication with a first section of a pipeline. The device 100 is configured to allow flue gas 112 to flow from the radiant section 113 through the convection section 103.

[0028] The heated hydrocarbon feed in line 133 may be mixed with the main dilution steam in line 137 and / or the fluid, such as water, in line 135. The fluid in line 135 may be steam, vapor, liquid, or a mixture thereof. The mixing of the heated hydrocarbon feed and the main dilution steam in line 137 and / or the fluid in line 135 may be carried out using any suitable mixing device, such as a dual-sprayer assembly, inside or outside the pyrolysis furnace 101, for example, outside the pyrolysis furnace 101. The fluid in line 135 may enter the first sprayer 35 of the dual-sprayer assembly, which may prevent or reduce hammering of the pipes (one or more) caused by sudden evaporation of the fluid when it is introduced into the heated hydrocarbon feed.

[0029] Secondary dilution steam in line 141 can be heated in the superheater tube assembly to produce second separator feed 147. The source of secondary dilution steam can be preheated primary dilution steam (e.g., in the convection section 103 of pyrolysis furnace 101). Either or both of the primary and secondary dilution steam can include acidic or process steam. Superheating the acidic or process dilution steam reduces the risk of corrosion from condensation of the acidic or process steam. The primary dilution steam in line 137 can be injected into the second sprayer 37 of the dual sprayer assembly, and the resulting feed mixture from the line can enter the convection tubes 117 of the second set for additional heating with flue gas (indicated by arrow 112) to produce first separator feed 139. First separator feed 139 can be mixed with second separator feed 147 and introduced into separator 153 to produce two phases, including a gaseous phase (top effluent) from line 155 and a liquid phase (bottom effluent) from line 157. Separator 153 may be referred to as a flash drum. The gas phase of line 155 may include volatile hydrocarbons and steam. The gas phase may be fed into the lower convection section tube assembly 119 in a second preheating zone 111 located at the lower half height of the convection section 103. The second preheating zone 111 may be near the radiant section 113 of the furnace, and the gas phase may pass through the crossover pipe 175 to the radiant section 113 of the pyrolysis furnace for cracking into the radiant section effluent of line 161. The liquid phase of line 157 may include non-volatile hydrocarbons, including coke precursors. The liquid phase of line 157 is cooled in heat exchanger 160. Heat exchanger 160 heats boiler feed water 159 into medium-pressure steam 164, for example, MP steam with a pressure of about 8 bar to about 20 bar, such as about 15 bar. MP steam 164 is fed into medium-pressure steam header 166 to provide MP steam feed stream 168 suitable for dilution steam or other medium-pressure steam applications for the furnace. Before cooling in heat exchanger 160, the liquid phase in line 157 may have a pressure approximately 1 bar higher than the pressure in intermediate pressure steam manifold 166. The pressure in intermediate pressure steam manifold 166 may be approximately 7 to approximately 17 bar. The pressure differential enables control valve pressure drop for level control in 160 and compensates for hydraulic losses in the exchanger and line.

[0030] It has been found that supplying boiler feed water 159 to heat exchanger 160 for heat exchange with the liquid phase of line 157 can reduce fresh water consumption and minimize flue gas temperatures for various hydrocarbon-containing feeds, including light crude oil. Specifically, less fluid from 135 is fed into the first sprayer 35 of the dual sprayer assembly 35, 37 to achieve separation. Conventional furnaces use heat exchanger 160 to cool the bottom material stream 157 of separator 153 using the furnace's colder feed, such as... Figure 1As shown in section 131. This results in a flue gas temperature higher than that described herein. It has been found that supplying high-temperature crude oil at inlet 131 increases the flue gas temperature and is typically managed by injecting fluid from 135 into the first sprayer 35 to reduce the temperature of the hydrocarbon stream. The amount of fluid injected is to provide the desired separation while maintaining a flue gas temperature of approximately 155°C or lower. Conventional furnaces use up to approximately 4 tons per hour (“tph”) of water to manage the flue gas temperature.

[0031] It has been found that directly supplying hydrocarbon-containing feed from the desalter 200 described herein to the furnace inlet 131 reduces, or in some cases, removes, the water supplied to the sprayers 35, 37. Providing the effluent directly from the desalter 200 to the furnace inlet 131 before it enters the inlet (instead of preheating the desalter effluent in the heat exchanger 160) provides a more efficient furnace, thus requiring less sprayer water and reducing flue gas temperature.

[0032] The temperature of the effluent from the desalter 200 can be about 90°C or lower, for example, about 70°C to about 85°C. Water is supplied to the sprayers 35 and 37 at a rate of about 2 tph or less. The hydrocarbon-containing feed passes through the sprayers 35 and 37 for cooling, and the flue gas passing through the convection section can produce an exhaust gas temperature of about 155°C or lower, for example, about 155°C or lower for heavy crude oil feed and / or about 143°C or lower for medium crude oil feed and / or about 142°C or lower for light crude oil feed.

[0033] The effluent from the radiant section of line 161 can be transported via line 162 and rapidly cooled in a transfer line exchanger (“TLE”) 170, generating saturated steam in steam drum 172, which can be superheated in the superheater convection section 120. The effluent 176 from TLE 170 can be supplied to tar separation drum 184 for the removal of pyrolysis fuel oil and coke. The top portion of tar separation drum 184 is supplied to heat exchanger 182, which condenses at least some product vapors (e.g., quench oil vapors) and generates high-pressure steam to high-pressure steam manifold 186. The high-pressure steam from high-pressure steam manifold 186 can be from about 30 bar to about 50 bar and can be used to generate electricity from the steam. The electricity can be used to drive a large turbine to power refrigeration equipment, or can be reintroduced into the furnace to one or more heat recovery exchangers, or a combination thereof.

[0034] Figure 2A schematic flow diagram of a desalter 200 according to this disclosure is described. The desalter 200 includes an effluent exchanger 204 capable of receiving a hydrocarbon-containing feed, such as crude oil feed, from a crude oil feed tank 202. The effluent from the hydrocarbon-containing feed and the desalted effluent exchanger 204 is passed into a preheating exchanger 206 to produce a preheated effluent having a temperature of, for example, from about 38°C to about 95°C. The preheating exchanger 206 receives a hot fluid 208, such as quench oil, quench water, medium-pressure steam, or a combination thereof, and cools it to a cooling fluid 210. The preheated effluent (which is heated in the preheating exchanger 206 by the hot fluid 208) is introduced into one or more desalters 212, 214, such as two desalters, to produce a desalted effluent. The one or more desalters 212, 214 mix the preheated heated effluent and separate a first phase, including salt and particles, from the desalted effluent. The desalting effluent is provided to the effluent exchanger 204 and supplied to inlet 131. The desalting effluent includes salts (e.g., Mg, Ca, Na, Cl, or combinations thereof) and / or particles in a reduced amount relative to the hydrocarbon feed from crude oil feed tank 202.

[0035] Figure 3 A flowchart describing an example method 300 for processing hydrocarbons according to some aspects of this disclosure. Method 300 may include:

[0036] Hydrocarbon-containing feed is introduced into the 302 desalting preheater unit (trail) which includes an effluent exchanger;

[0037] At least a portion of the hydrocarbon-containing feed is guided from the desalter preheater unit 304 to the feed inlet of the convection section of the steam cracker;

[0038] 306 fuel is burned at multiple burners to provide heat to the radiant and convection sections of the steam cracker;

[0039] In the convection section, the hydrocarbon-containing feed 308 is heated in operating mode to obtain a heated feed mixture;

[0040] In the separator, the heated feed mixture from the convection section is separated from the bottom effluent of 310; and

[0041] Boiler feed water is used in the heat exchanger to cool the bottom effluent of 312.

[0042] The crude oil feed introduced into the desalter preheater unit to be heated may have a temperature of about 60°C or lower. In some embodiments, the hydrocarbon feed is provided to the effluent exchanger before and after being introduced into at least one desalter. It is desirable to control the temperature of the portion of the hydrocarbon feed directed to the inlet of the convection section at a temperature of about 60°C or lower from the flue gas temperature of the steam cracker. The hydrocarbon feed at the inlet of the convection section (e.g., effluent from the desalter preheater unit) may range, for example, from about 38°C to about 105°C. The hydrocarbon feed may be crude oil feed, light crude oil feed, heavy crude oil feed, or a combination thereof. The flue gas temperature is maintained at a temperature below about 150°C.

[0043] In some embodiments, water of about 0 tph to about 2 tph is introduced into a portion of the convection section of the steam cracker, for example, through sprayers 35 and 37. The water in the sprayers may be at a temperature of about 35°C to about 125°C. The amount of water introduced into the convection section depends on the type of hydrocarbon feed introduced into the desalting preheater unit. For hydrocarbon feeds comprising heavy crude oil and / or medium crude oil, it is preferable to introduce about 0 tph of water into the convection section during combustion. In some embodiments, the hydrocarbon feed comprises medium crude oil, light crude oil, or a combination of medium crude oil and condensate, and the heat energy supplied to the radiant and convection sections of the steam cracker during combustion is about 120 MW to about 130 MW. As used herein, “condensate” has an API specific gravity greater than 45°. “Light crude oil” has an API specific gravity of 40°–45°. “Medium crude oil” has an API specific gravity from 36° to less than 40°. The "heavy crude oil" has an API specific gravity of less than 36°, preferably from 35° to less than 36°. Evaporation in the flash / liquid separator vessel 153 is controlled based on one or more of the following temperatures: lower convection section manifold 119 temperature, flue gas temperature, SCR bed 180 temperature, and AIG 181 temperature. It has been found that heavy crude oil provides more effluent to the lower convection section manifold 119, which increases the temperature relative to lighter crude oil. Without being bound by theory, it is believed that the higher the temperature of the separator topsoil for heavy crude oil, the higher the expected separation point for removing coking precursor molecules from the heavy crude oil. For light crude oil, fewer trace amounts of these coking precursors can be entrained in the topsoil at lower temperatures; therefore, a lower temperature is maintained for light crude oil to prevent coking precursor entrainment in line 119.

[0044] The use of boiler feed water to cool the bottom effluent in heat exchanger 160 is controlled according to the type of hydrocarbon feed and / or the temperature of the bottom effluent. In some embodiments, cooling the bottom effluent is used to provide a cooler bottom effluent for storage, further processing, sale, or a combination thereof. The use of boiler feed water in the heat exchanger to cool the bottom effluent provides a predetermined temperature for the lower half-height portion of the convection section, based on the coking hydrocarbon feed, at a predetermined temperature of about 350°C to about 460°C (e.g., about 415 to about 460°C for feeds containing heavy hydrocarbons, and about 435°C or lower for feeds containing light hydrocarbons), wherein the lower half-height portion is located between the radiant section 113 of the furnace and the SCR bed 180. In some embodiments, the use of boiler feed water to cool the bottom effluent in the heat exchanger is controlled to provide a predetermined temperature for the SCR bed 180 located between the convection sections of the furnace. The inlet temperature of the SCR bed 180 is about 325°C to about 425°C, for example, about 340°C to about 370°C. In the heat exchanger 160, the temperature of the bottom effluent 157 is reduced by about 20°C to about 50°C.

[0045] The top effluent 155 is separated from the heated feed mixture and introduced into the lower half of the convection section. The furnace effluent leaving the radiant section of the furnace is cooled with boiler feed water to generate steam with a vapor pressure of about 50 bar or higher, thereby supplying steam to the steam drum 172 and introducing the steam into the furnace section.

[0046] Boiler feed water 174 can be supplied to at least one heat recovery exchanger 171 located in the upper half of the convection section, and the boiler feed water can be preheated with heat energy supplied through multiple burners (not shown). The preheated boiler feed water can be directed to steam drum 172. Example

[0047] Table 1 below illustrates example furnaces of this disclosure, for example... Figure 1 and Figure 2 The predicted performance of the furnace described herein is based on simulation. "SoR" means start of operation, and "EoR" means end of operation.

[0048] Table 1 Predicted performance of example furnaces

[0049]

[0050]

[0051] As can be seen from the data in Table 1, lighter feeds result in reduced heat transfer from heat exchanger 160 to the feed, thus enabling a variety of feeds. Water injection is only used at a rate of 2 tph at the end of operation for light crude oil. Water consumption is reduced by approximately 1 tph to approximately 4 tph compared to other furnace designs. Additional water consumption is reduced compared to furnace operation with similar flue gas temperatures. Flue gas temperatures are shown as below 155°C in all simulations. Furthermore, the flue gas temperature range is narrow for each feed type. Conventional furnaces typically show flue gas temperatures varying by a maximum of 100°C. In contrast, the flue gas temperature variations summarized in Table 1 are less than 80°C, for example, from approximately 5°C to approximately 20°C, and from approximately 10°C to approximately 15°C. This narrow temperature variation indicates highly efficient feed flexibility. Furnace ignition is significantly reduced compared to conventional furnaces, especially for crude oil feeds that can use approximately 155 MW or more. In summary, the desalting unit 200 arrangement and the supply of desalting unit effluent to the furnace inlet provide a highly efficient and flexible furnace that reduces power and water consumption.

[0052] Overall, the methods and systems described herein provide flexible, sustainable, and efficient cracking of hydrocarbons, enabling furnace temperature management for flexible hydrocarbon feedstocks and operating conditions. The furnace incorporates service components with certain temperatures into portions of the furnace to exchange temperature between the service components and the furnace. Example schemes described herein include supplying boiler feed water to a heat exchanger for heat exchange and reducing the furnace temperature in the lower half of the furnace, which subsequently reduces total fresh water consumption and minimizes flue gas temperature for a variety of hydrocarbon feedstocks under different operating modes.

[0053] List of Implementation Plans

[0054] This disclosure may also include the following non-limiting aspects and / or implementation methods:

[0055] A1. A steam cracking method comprising: introducing a hydrocarbon-containing feed into a desalter preheater unit including an effluent exchanger; directing at least a portion of the hydrocarbon-containing feed from the desalter preheater unit to the feed inlet of the convection section of a steam cracker; burning fuel at a plurality of burners to provide heat to the radiant section of the steam cracker and the convection section of the steam cracker; and heating the hydrocarbon-containing feed in the convection section in an operating mode to obtain a heated feed mixture, separating the bottom effluent from the heated feed mixture in the convection section in a separator, and cooling the bottom effluent using boiler feed water in a heat exchanger.

[0056] The method of A2.A1, wherein the hydrocarbon feed is provided to the effluent exchanger before and after the hydrocarbon feed is introduced into at least one desalter.

[0057] The methods A3, A1, or A2 further include controlling the temperature of said portion of the hydrocarbon-containing feed directed to the inlet of the convection section to a temperature within approximately 60°C or less of the flue gas temperature of the steam cracker.

[0058] The method in A4.A3, wherein the hydrocarbon-containing feed from the desalter preheater unit to the convection inlet is approximately 85°C to approximately 105°C.

[0059] A5. Any of the methods in A1 to A4, wherein the hydrocarbon feedstock contains crude oil.

[0060] A6. The method of any one of A1 to A5, wherein the hydrocarbon-containing feed has a temperature of about 60°C or lower when it is introduced into the desalting preheating unit for heating.

[0061] The method of any one of A7, A1 to A6, wherein the steam cracking furnace has an exhaust gas temperature of less than about 150°C.

[0062] The method of any one of A8, A1 to A7 further includes introducing about 0.1 tph to about 2 tph of water into a portion of the convection section of the steam cracker.

[0063] The method of any one of A9, A1 to A7, wherein the hydrocarbon feed comprises heavy crude oil, medium crude oil or a combination thereof, and water is not introduced into a portion of the convection section during combustion.

[0064] The method of any one of A10, A1 to A8, wherein the hydrocarbon feed comprises medium crude oil, light crude oil, or a combination of medium crude oil and condensate, and the heat energy supplied to the radiant and convective sections of the steam cracker during combustion is about 120 MW to about 130 MW.

[0065] The method of any one of A11 to A10 further includes directing steam from the heat exchanger to the steam header.

[0066] The methods of A12 and A11 also include supplying dilution steam from the steam header to the convection section of the furnace at a pressure of about 8 bar to about 15 bar.

[0067] The method of A13.A11, wherein cooling the bottom effluent with boiler feed water in a heat exchanger includes controlling the temperature of the bottom effluent based on the type of hydrocarbon-containing feed and / or the temperature of the bottom effluent.

[0068] The method of A14.A11, wherein cooling the bottom effluent in a heat exchanger includes supplying boiler feed water to the heat exchanger to provide a predetermined temperature for the lower half-height portion of the convection section, wherein the lower half-height portion is disposed between the NOx reduction bed and the radiant section of the furnace.

[0069] The methods of A15 and A11, wherein the amount of boiler feed water supplied to the heat exchanger is determined based on a predetermined temperature of the NOx reduction bed located in the convection section of the furnace.

[0070] The methods of A16 and A13, wherein the temperature of the bottom effluent in the heat exchanger is reduced by about 20°C to about 50°C.

[0071] The method of any one of A17.A1 to A16 further includes separating the top effluent from the heated feed mixture and introducing the top effluent into the lower half height portion of the convection section.

[0072] The method of any one of A18.A1 to A17 further includes cooling the furnace effluent leaving the radiant section of the furnace with boiler feed water to generate steam with a steam pressure of about 50 bar or higher, thereby supplying steam to the steam drum and introducing the steam into the furnace section.

[0073] The methods of A19 and A18 further include introducing furnace effluent into a separation drum, condensing product vapor from the separation drum into steam with a steam pressure of about 30 bar to 50 bar in a condenser, generating electricity from the steam, and introducing boiler feed water into the condenser.

[0074] The method of any one of A20.A1 to A19 further includes supplying boiler feed water to at least one heat recovery exchanger disposed in the upper half height portion of the convection section, and preheating the boiler feed water with heat energy supplied through a plurality of burners.

[0075] The methods of A21 and A20 also include directing preheated boiler feed water to the steam drum.

[0076] B1. Equipment, comprising: a steam cracker including a convection section and a radiation section; a desalter preheating unit connected to the feed inlet of the convection section of the steam cracker, the desalter preheating unit comprising: an effluent exchanger, a temperature-regulating preheater in fluid communication with the effluent exchanger, and at least one desalter in fluid communication with the temperature-regulating heater, wherein at least one desalter is in fluid communication with the effluent exchanger; and a plurality of burners disposed within the steam cracker capable of supplying heat energy by burning fuel.

[0077] The equipment in B2.B1 also includes a heat exchanger capable of cooling boiler feed water, wherein the heat exchanger is capable of directing steam to the steam manifold.

[0078] The equipment of B3.B2 also includes a controller capable of controlling and / or regulating the amount of steam directed to the steam manifold.

[0079] Equipment of type B4, B2 or B3, wherein the steam manifold is capable of supplying steam to the convection section of the steam cracker.

[0080] The equipment of any one of B5, B1 to B4 further includes a steam drum connected to a heat recovery exchanger disposed in the upper half height portion of the convection section of the steam cracker and capable of receiving preheated boiler feed water therefrom.

[0081] The equipment of any one of B6, B1 to B5 also includes a separation drum capable of receiving furnace effluent from the radiant section of a steam cracker.

[0082] The B7.B6 apparatus also includes a product vapor cooler in fluid communication with the separation drum, which is capable of generating vapor with a vapor pressure of about 50 bar or higher.

[0083] The equipment of B8.B7 also includes a steam manifold capable of supplying steam for one or more applications selected from: supplying power to turbines, supplying power to refrigeration, supplying power to compression equipment, and combinations thereof.

[0084] C1. A steam cracking method, comprising: introducing a hydrocarbon-containing feed directly from a hydrocarbon feed tank into a desalting preheater unit; separating a first portion and a second portion of the hydrocarbon-containing feed in the desalting preheater unit, wherein separating the first and second portions of the hydrocarbon-containing feed comprises: introducing the hydrocarbon-containing feed into an effluent exchanger; preheating the hydrocarbon-containing feed from the effluent exchanger in a temperature-controlled preheater in fluid communication with the effluent exchanger; separating the first and second portions of the preheated effluent from the temperature-controlled preheater in at least one desalting unit in fluid communication with the temperature-controlled heater, wherein at least one desalting unit is in fluid communication with the effluent exchanger; introducing the first portion of the preheated effluent into the effluent exchanger; guiding the first portion of the preheated effluent from the desalting preheater unit to the feed inlet of the convection section of a steam cracker; and burning fuel at a plurality of burners to provide heat energy to the radiant section and the convection section of the steam cracker.

[0085] All documents mentioned herein are incorporated herein by reference, including any priority documents and / or test procedures, provided they do not contradict this document. As will be apparent from the foregoing general description and specific embodiments, while the form of this disclosure has been set forth and described, various changes may be made without departing from the spirit and scope of this disclosure. Therefore, it is not intended to limit the scope of this disclosure. Similarly, the term “comprising” is considered synonymous with the term “including.” Likewise, whenever a component, element, or group of elements is preceded by the conjunction “comprising,” it should be understood that we also consider a group of the same components or elements preceded by the conjunctions “substantially composed of,” “composed of,” “selected from,” or “is,” and vice versa.

[0086] For the sake of brevity, this document only explicitly discloses certain ranges. However, a range not explicitly stated can be described by combining any lower limit with any upper limit, and a range not explicitly stated can be described by combining any lower limit with any other lower limit; similarly, a range not explicitly stated can be described by combining any upper limit with any other upper limit. Furthermore, even if not explicitly stated, each point or individual value within a range is included between its endpoints. Thus, each point or individual value can serve as its own lower or upper limit, combined with any other point or individual value or any other lower or upper limit, to describe a range not explicitly stated.

Claims

1. Steam cracking methods, including: A hydrocarbon-containing feed is introduced into a desalting preheater unit comprising an effluent exchanger and at least one desalting unit, wherein at least one desalting unit is in fluid communication with the effluent exchanger; At least a portion of the hydrocarbon-containing feed is directed from the desalter preheater unit to the feed inlet of the convection section of the steam cracker; Fuel is burned at multiple burners that provide heat to the radiant section and convection section of the steam cracker. In the convection section, the hydrocarbon-containing feed is heated in operating mode to obtain a heated feed mixture; The bottom effluent is separated from the heated feed mixture in the convection section in the separator; and Boiler feed water is used to cool the bottom effluent in the heat exchanger. The hydrocarbon feed is supplied to the effluent exchanger before and after the hydrocarbon feed is introduced into at least one desalter.

2. The method of claim 1, further comprising controlling the temperature of said portion of the hydrocarbon-containing feed directed to the inlet of the convection section to a temperature within 60°C or lower than the flue gas temperature of the steam cracker.

3. The method according to claim 2, wherein the hydrocarbon-containing feed from the desalter preheater unit to the inlet of the convection section is 85°C-105°C.

4. The method according to any one of claims 1 to 3, wherein the hydrocarbon feed comprises crude oil.

5. The method according to claim 4, wherein when the desalting preheater unit is introduced for heating, the hydrocarbon-containing feed has a temperature of 60°C or lower.

6. The method according to any one of claims 1 to 3, wherein the flue gas temperature of the steam cracking furnace is below 150°C.

7. The method according to any one of claims 1 to 3, further comprising introducing 0.1 tph to 2 tph of water into a portion of the convection section of the steam cracker.

8. The method according to any one of claims 1 to 3, wherein the hydrocarbon feed comprises heavy crude oil, medium crude oil, or a combination thereof, and water is not introduced into a portion of the convection section during fuel combustion at multiple burners.

9. The method according to any one of claims 1 to 3, wherein the hydrocarbon feed comprises medium crude oil, light crude oil, or a combination of medium crude oil and condensate, and the thermal energy supplied to the radiant and convective sections of the steam cracker during combustion is 120 MW to 130 MW.

10. The method according to any one of claims 1 to 3, further comprising directing steam from the heat exchanger to the steam header.

11. The method of claim 10, further comprising supplying dilution steam from the steam manifold to the convection section of the furnace at a pressure of 8 to 15 bar.

12. The method of claim 10, wherein cooling the bottom effluent using boiler feed water in the heat exchanger comprises controlling the temperature of the bottom effluent according to the type of hydrocarbon-containing feed and / or the temperature of the bottom effluent.

13. The method of claim 10, wherein cooling the bottom effluent in the heat exchanger comprises supplying boiler feed water to the heat exchanger to provide a predetermined temperature for the lower half-height portion of the convection section, wherein the lower half-height portion is disposed between the NOx reduction bed and the radiant section of the furnace.

14. The method of claim 10, wherein the amount of boiler feed water supplied to the heat exchanger is determined based on a predetermined temperature of the NOx reduction bed located in the convection section of the furnace.

15. The method of claim 12, wherein the temperature of the bottom effluent is reduced by 20°C to 50°C in the heat exchanger.

16. The method according to any one of claims 1 to 3, further comprising separating the top effluent from the heated feed mixture and introducing the top effluent into the lower half height portion of the convection section.

17. The method according to any one of claims 1 to 3, further comprising cooling the furnace effluent leaving the radiant section of the furnace with boiler feed water to generate steam having a vapor pressure of 50 bar or higher, supplying steam to the steam drum, and introducing the steam into the furnace section.

18. The method of claim 17, further comprising introducing furnace effluent into a separation drum, condensing product vapor from the separation drum into steam having a steam pressure of 30 bar to 50 bar in a condenser, generating electricity from the steam, and introducing boiler feed water into the condenser.

19. The method according to any one of claims 1 to 3, further comprising supplying boiler feed water to at least one heat recovery exchanger disposed in the upper half height portion of the convection section, and preheating the boiler feed water with heat energy supplied through a plurality of burners.

20. The method of claim 19, further comprising directing preheated boiler feed water to a steam drum.

21. Equipment, including: Steam cracking furnaces including convection and radiation sections; A desalter preheating unit connected to the feed inlet of the convection section of a steam cracker, the desalter preheating unit comprising: an effluent exchanger, a temperature-regulating preheater in fluid communication with the effluent exchanger, and at least one desalter in fluid communication with the temperature-regulating heater, wherein the at least one desalter is in fluid communication with the effluent exchanger; and Multiple burners installed inside a steam cracker are capable of supplying heat energy by burning fuel.

22. The apparatus of claim 21 further includes a heat exchanger capable of cooling boiler feed water, wherein the heat exchanger is capable of directing steam to a steam manifold.

23. The apparatus of claim 22 further includes a controller capable of controlling and / or regulating the amount of steam directed to the steam manifold.

24. The apparatus according to any one of claims 21 to 23, further comprising a steam drum connected to a heat recovery exchanger disposed in the upper half height portion of the convection section of the steam cracker and capable of receiving preheated boiler feed water therefrom.

25. Steam cracking methods, including: Hydrocarbon-containing feed is introduced directly from the hydrocarbon feed tank into the desalter preheater unit; Separating a first portion and a second portion of hydrocarbon-containing feed in a desalter preheater unit, wherein separating the first portion and the second portion of hydrocarbon-containing feed comprises: introducing the hydrocarbon-containing feed into an effluent exchanger; preheating the hydrocarbon-containing feed from the effluent exchanger in a temperature-controlled preheater in fluid communication with the effluent exchanger; separating the first portion and the second portion of the preheated effluent from the temperature-controlled preheater in at least one desalter in fluid communication with the temperature-controlled heater, wherein at least one desalter is in fluid communication with the effluent exchanger; introducing the first portion of the desalted preheated effluent into the effluent exchanger; guiding the first portion of the desalted preheated effluent from the desalter preheater unit to the feed inlet of the convection section of a steam cracker; and burning fuel at a plurality of burners to provide heat energy to the radiant section and the convection section of the steam cracker.

Images