WO2023114633A1

WO2023114633A1 - Steam cracking furnace and process

Info

Publication number: WO2023114633A1
Application number: PCT/US2022/080535
Authority: WO
Inventors: Mark A. Rooney; Richard Young; David Spicer; William A. ASLANER
Original assignee: Exxonmobil Chemical Patents Inc.
Priority date: 2021-12-16
Filing date: 2022-11-29
Publication date: 2023-06-22

Abstract

The present disclosure provides processes and apparatuses for cracking a hydrocarbon- containing feed. The process includes introducing the hydrocarbon-containing feed to a desalter preheat train having an effluent interchanger. The process includes directing a portion of the hydrocarbon-containing feed from in the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace. The process includes combusting fuel proximate to a plurality of burners that provide thermal energy to a radiant section and a 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 process includes separating a bottoms effluent from the heated feed mixture of the convection section in a separator. The process includes cooling the bottoms effluent in a heat exchanger using boiler feed water.

Description

STEAM CRACKING FURNACE AND PROCESS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63/290,301 having a filing date of December 16, 202.1, the disclosure of winch is incorporated herein by reference in its entirety.

FIELD

[0002] Embodiments of the present disclosure generally relate to methods and systems for cracking hydrocarbons. In particular, the present disclosure relates to managing furnace temperatures for flexible use of hydrocarbon-containing feeds and operating conditions. BACKGROUND

[0003] Steam cracking, also referred to as pyrolysis, refers to a commercial process for the production of light olefins, especially ethylene and propylene. In typical steam cracking processes, 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 vapor feed/dilution steam mixture is rapidly heated in the radiant section to achieve thermal cracking of hydrocarbons. After a predetermined amount of thermal cracking occurs, the furnace effluent is rapidly quenched in either an indirect heat exchanger or by the direct injection of a quench oil stream.

[0004 ] A byproduct of the cracking process includes carbon deposits, referred to as "coke," on the inner surfaces of the radiant tubes of the furnace. Depending on the hydrocarbon feed being cracked, coke may also be deposited in certain tubes in the convection section, or in the quench system of the furnace. Decoking operations can impact cracking throughput, and increasing time between decoking operations is a goal for cracking processes. Increasing time between decoking operations by preventing coke accumulation and increasing hydrocarbon conversion involves selective and controlled heating and cooling of portions of the steam cracking furnace. Controlled heating typically uses high amounts of energy from the furnace which is at least partially released from the furnace. Moreover, steam cracking furnaces have different operating conditions depending on the type of feed, processing rates, rate of fouling, and environmental considerations. Furnaces need to be flexible to handle different super high pressure or high pressure steam rates and different flue gas rates for different convection duties. [0005] Thus, there is a need to minimize energy losses for enhanced efficiency furnaces, efficiently promote conversion of hydrocarbons, and reduce furnace stack temperatures for a variety of feeds. SUMMARY

[0006] In at least one embodiment, a steam cracking process includes introducing a hydrocarbon-containing feed to a desalter preheat train comprising an effluent interchanger. The process includes directing at least a portion of the hydrocarbon-containing feed from the desalter preheat tram to a feed inlet of a convection section of a steam cracking furnace. The process includes combusting a fuel at a plurality of burners to provide thermal energy to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace. The process includes heating the hydrocarbon-containing feed in an operating mode in the convection section to obtain a heated feed mixture. The process includes separating a bottoms effluent from the heated feed mixture of the convection section in a separator. The process includes cooling the bottoms effluent in a heat exchanger using boiler feed water.

[0007] In at least one embodiment, an apparatus includes a steam cracking furnace comprising a convection section and a radiant section. A desalter preheat train is coupled to a feed inlet of a convection section of the steam cracking furnace. The desalter preheat tram includes an effluent interchanger, a trim preheater in fluid communication with the effluent interchanger, and at least one desalter in fluid communication with the trim heater. The at least one desalter is in fluid communication with the effluent interchanger, and a plurality of burners is disposed within the steam cracking furnace and is capable of supplying thermal energy to the steam cracking furnace by combusting a fuel.

[0008] In at least one embodiment, a steam cracking process includes introducing' a hydrocarbon-containing feed from a hydrocarbon-feed tank directly to a desalter preheat train. The process includes separating a first portion and a second portion of the hydrocarbon- containing feed in the desalter preheat train. Separating includes introducing the hydrocarbon- containing feed in an effluent interchanger. The process includes preheating the hydrocarbon- containing feed (from the effluent interchanger) in a trim preheater that is in fluid communication with the effluent interchanger. The process includes separating a first portion and a second portion of the preheated effluent from the trim preheater in at least one desalter in fluid communi cation with the trim heater. The at least one desalter is in fluid communication with the effluent interchanger. The process includes introducing the first portion of the preheated effluent to the effluent interchanger. The process includes directing the first portion of the preheated effluent from the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace. The process includes combusting a fuel at a plurality of burners to provide thermal energy' to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

[0010] FIG. 1 depicts an apparatus for processing hydrocarbons, in accordance with an embodiment.

[0011] FIG. 2 depicts a schematic flow diagram of a desalter configuration, in accordance with an embodiment.

[0012] FIG. 3 depicts a flow diagram of an example method for processing hydrocarbons, in accordance with an embodiment.

[0013] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0014] The present disclosure provides methods and systems for flexible, sustainable, and efficient cracking of hydrocarbons. In particular, the present disclosure provides methods and systems for managing furnace temperatures for flexible hydrocarbon-containing feeds and operating conditions. A hydrocarbon pyrolysis reactor (or furnace) of methods and systems of the present disclosure can include a convection section and a radiant section. As used herein, a convection section can be a portion of the furnace where a hydrocarbon-containing feed can be treated by convection heating. For example, convection heating, as used herein, can be the indirect heat exchange of hot flue gas from the radiant section in passages having heat conducting surfaces, such as a bank of metal tubes. The convection section can include one or more convection zones, each zone having an inlet to and an outlet from the convection section. A convection section can include one or more heating zones, as well as a preheating zone which preheats hydrocarbon-containing feeds in a heat exchanger using heated bottoms from a vapor liquid separator. Each convection zone can be associated with a tube bank for effecting heat exchange. As used herein, the terms “downstream” and “upstream” refer to a relative position along the furnace in a flow' direction of hydrocarbon and/or water/steam through tubing, but (e g., as shown in FIG. 1) the terms do not require flow of the hydrocarbon and/or water/steam through a single, continuous tubing. As used herein, “boiler feed water’ (BFW) refers to water that is treated and deaerated to be suitable for reliable steam generation at high pressures. For boiler waters for pressures of about 50 bar or greater, BFW is demineralized to have almost no conductivity and trace amounts of various boiler foulants. BFW is deaerated usually with steam to remove trace amounts of oxygen that can rapidly corrode a boiler. The deaeration process leaves the boiler feed water at about 110 °C to about 125 °C and at a pressure higher than the desired steam pressure (e.g. for 100 bar steam, the BFW is usually about 120 about to about 150 bar).

[0015] Conventional furnaces have been effective for cracking certain hydrocarbons, such as gas oil and naphtha. Steam cracking economics sometimes favor cracking other types of hydrocarbons, such as low cost heavy hydrocarbon-containing feed, such as crude oil or atmospheric resid (e.g., atmospheric pipestill bottoms). Heavy feeds can contain non-volatile components that can cause coke accumulation within the furnaces. A hydrocarbon-containing feed comprising non-volatile components of a crude is sometimes called a “crude feed” herein. Thus, suitable hydrocarbon-containing feed for the processes and systems of this disclosure include those comprising, consisting essentially or, or consisting of, a crude oil. “Crude oil” or “crude” interchangeably mean hydrocarbon-containing compositions that can be utilized as a feed to a crude oil refinery' as a feed.

[0016] It has been discovered that arranging furnace services can increase flexibility for use of a broad range of hydrocarbons, such as light hydrocarbons to heavy hydrocarbons. As used herein, “services” refer to one or more furnace components, such as arrangements of piping, water boilers, boiler feed water economizers, steam generators, steam superheater, steam overheat separator, or other components configured to exchange energy with one another and or portions of the furnace. As used herein, “flexibility” refers to an ability of a same furnace to process different types of hydrocarbon-containing feeds in one or more operating modes, such as while maintaining operation within certain process and environmental limitations. The ability to process different types of hydrocarbon-containing feeds at different processing rates or seventies can be determined by hydrocarbon-containing feed availability and economics. In addition to processing different hydrocarbon types, flexibility includes an ability' to change modes of operations for both cracking and decoking processes. Additionally, increasing sustainability objectives for overall energy efficiency for various hydrocarbon-containing feeds has been considered for furnace design and configurations. Some furnaces have increased operating flexibility, however, flexibility can be at the expense of energy efficiency In particular, flexibility' results in different super high pressure (SHP) (e.g., about 100 bar or greater) or high pressure (HP) (e.g., about 30 bar or greater, such as about 30 to about 50) steam rates and different flue gas rates for different convection duties. Under certain operating conditions, stack temperatures can increase to high temperatures, such as about 100 °C or greater, such as about 150 °C or greater. It has been discovered that having a low stack temperature for high efficiency furnaces is possible by delivering low temperature services, such as about 125 °C or lower, to the upper convection sections using one or more approaches of the present disclosure. As used herein, the term "‘stack temperature” refers to a temperature of the flue gas above the inlet of the furnace which is released from the furnace after passing the convection section of the furnace.

[0017] In some embodiments, a desalter arrangement is capable of providing a hydrocarbon-containing feed and effluent interchange! for hydrocarbon-containing feed preheating of a desalter preheat train prior to preheating the hydrocarbon-containing feed, and/or providing a hydrocarbon-containing feed and effluent interchanger prior to providing the effluent to the furnace. A desalter preheat configuration of the present disclosure can provide reduced furnace feed temperature, reduced sparger water injection which can achieve separation of feed components from the hydrocarbon-containing feed for enhanced energyefficiency, and reduced fresh water consumption. In some embodiments, the effluent interchanger cools the desalted effluent while heating the incoming hydrocarbon-containing feed. The desalter operates at a higher temperature than the temperature of the hydrocarbon- containing feed fed to the furnace. Since there is a need for a high temperature between two steps at lower temperature (tanks at cooler temperature, and furnace feed at cooler temperature), it makes sense to interchange the heat between feed and effluent with a trim heater.

[0018] Another approach can include shifting a bottoms cooling surface from a feed preheat to another service, such as super high pressure boiler feed water preheat for boilers or medium pressure steam (e.g., about 7 bar to about 17 bar) generation to maintain low feed temperature to upper convection section. As used herein, "‘boilers” are distinct from transfer line exchangers which also boil super high pressure steam. The “boilers” of the present disclosure can preheat super high pressure boiler feed water which enables capturing energy benefit without incurring a furnace energy disadvantage or flexibility restriction. Another approach provided herein can include shifting furnace effluent vapor cooler and first stage bottom pump around heat from SHP boiler feed water preheat to a low temperature service, such as super high pressure boiler feed water preheat for boilers, medium pressure steam generation, and/ or high pressure steam generation to maintain low SHP boiler feed water temperature to upper convection section.

[0019] The terms “convert,” “converting,” “crack,” and “cracking” are defined broadly herein to include any suitable molecular decomposition, breaking apart, conversion, dehydrogenation, and/or reformation of hydrocarbon or other organic molecules, by means of at least pyrolysis heat, and can optionally include supplementation by one or more processes of catalysis, hydrogenation, diluents, stripping agents, and/or related processes.

[0020] Hydrocarbon-containing feeds that can be processed using the methods and systems described herein can include recycle gas such as ethane, steam cracked oil/residue admixtures, gas oils, heating oil, jet fuel, diesel, kerosene, gasoline, coker naphtha, steam cracked naphtha, catalytically cracked naphtha, hydrocrackate, reformate, raffinate reformate, Fischer-Tropsch liquids, Fischer-Tropsch gases, natural gasoline, distillate, crude oil such as heavy crude oil, light virgin naphtha (LVN), atmospheric pipestill bottoms, vacuum pipestill streams including bottoms, wide boiling range naphtha to gas oil condensates, heavy non-virgin hydrocarbon streams from refineries, vacuum gas oils, heavy gas oil, naphtha contaminated with crude, atmospheric residue, heavy residue, hydrocarbon gas/'residue admixtures, hydrogen/residue admixtures, liquid petroleum gas (LPG), and mixtures thereof.

[0021] Unless otherwise stated, all percentages, parts, ratios, etc., are by weight. Unless otherwise stated, a reference to a compound or component includes the compound or component by itself, and/or the compound or component in combination with other compounds or components, such as mixtures of compounds. Further, when an amount, concentration, or other value or parameter is given as a list of upper values and lower values, this is to be understood as specifically disclosing all ranges formed from any pair of an upper value and a lower value, regardless of whether ranges are separately disclosed.

[0022] FIG. 1 depicts an apparatus 100 in accordance with some aspects of the present disclosure. The heating of the hydrocarbon-containing feed 131 can take any suitable form, such as heating by indirect contact of the hydrocarbon-containing feed in a convection section 103 of a furnace 101 as shown in FIG. 1. The convection section 103 can include a first preheating zone 105 with a first and second bank of convection tubes 115, 1 17. The first bank of convection tubes 115 can be di sposed at a first pre-heating section 107 of the first pre-heating zone 105 and the second bank of convection tubes 117 can be disposed substantially adjacent the first bank of convection tubes 115 at a second pre-heating section 109 of the first preheating zone 105. The hydrocarbon-containing feed disposed within line 131 can be fed into the first bank of convection tubes 115 and heated by convection with hot flue gases of line 112 from the radiant section 113 that passes through the convection section 103 over each bank of convection tubes (e.g., 115, 117). The hydrocarbon-containing feed of line 131 at the inlet of the first bank of convection tubes 1 15 can have a temperature of about 20 °C to about 300 °C. such as about 25 °C to about 250 °C, such as about 25 °C to about 100 °C, such as about 32 °C to about 65 °C, or 150 °C to about 250 °C (e.g., in some crude applications), and/or a pressure of about 790 kPa io about 1825 kPa, such as about 800 kPa to about 1800 kPa, such as 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 disposed between the second pre-heating section 109 and the superheater convection section 120. AIG 181 injects ammonia in even distribution within the flue gas so that the ammonia in the flue gas can react to the nitrogen oxide in the flue gas to remove the nitrogen oxides. Without being bound by theory, it is believed that an AIG temperature that is too high allows the ammonia to be oxidized to nitrogen oxide. It has been discovered that maintaining a temperature below a predetermined temperature enables maintaining adequate ammonia concentration available for reaction.

[0023] As will be understood by those skilled in the art, in commercial operations, one or more (e.g., each) of the tube banks can have multiple, parallel-flow systems of tubes, not merely a single tube within the furnace, e.g., as described in U.S. Pat. No. 3,365,387, which is incorporated herein by reference. Thus, any one or more than one flow path can be isolated by appropriate valving, thereby permitting a decoking cycle to be run on one or more selected off- stream tubing flow-paths, without disturbing the overall hydrocarbon pyrolysis process in the remaining on-stream tubes. Individual banks of tubes can be isolated, as disclosed in U.S. Pat. No. 8,864,977, which is incorporated herein by reference.

[0024] In some embodiments, a selective catalytic reduction bed (SCR) 180 for nitrogen oxide reduction is disposed between the first pre-heating section 107 and the second preheating section 109. In some embodiments, the steam cracking furnace includes a convection section 103 and a radiant section 1 13 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 line. The apparatus 100 is configured to flow flue gas 112 from the radiant section 113 through the convection section 103,

[0025] The heated hydrocarbon-containing feed of line 133 can be mixed with primary dilution steam of line 137 and/or a fluid of line 135 such as a water. The fluid of line 135 can be vapor, steam, liquid, or a mixture thereof. The mixing of the heated hydrocarbon-containing feed and the primary' dilution steam of line 137 and/or fluid of line 135 can occur inside or outside of the pyrolysis furnace 101, such as outside the pyrolysis furnace 101 using any suitable mixing device, such as a double sparger assembly. The fluid of line 135 can enter a first sparger 35 of the double sparger assembly, which can avoid or reduce hammering of the pipe(s) caused by sudden vaporization of the fluid upon introduction of the fluid into the heated hydrocarbon-containmg feed.

[0026] A secondary dilution steam of line 141 can be heated in a superheater tube bank to produce a second separator feed 147. The source of the secondary dilution steam can be primary dilution steam that has been superheated, such as in the convection section 103 of the pyrolysis furnace 101. Either or both of the primary' and secondary dilution steam streams can include sour or process steam. Superheating the sour or process dilution steam can reduce the risk of corrosion from condensation of sour or process steam. The primary dilution steam of line 137 can be injected into a second sparger 37 of the double sparger assembly, and the resulting stream mixture of line can enter the second bank of convection tubes 1 17 for additional heating with flue gas (represented by arrow 112) to produce a first separator feed 139. The first separator feed 139 can be mixed with the second separator feed 147 and introduced to a separator 153 to produce two phases, including a vapor phase of line 155 (overhead effluent) and a liquid phase of line 157 (bottoms effluent). The separator 153 can be called a flashing drum. The vapor phase of line 155 can include volatile hydrocarbons and steam. The vapor phase can be fed to a lower convection section tube bank 119 in a second preheating zone 111 disposed at a lower 1 /2 height of the convection section 103. The second preheating zone 111 can be proximate to the radiant section 113 of the furnace, and the vapor phase can pass through crossover pipes 175 to the radiant section 113 of the pyrolysis furnace for cracking into a radiant section effluent of line 161. The liquid phase of line 157 can include non-volatile hydrocarbons, including coke precursors. The liquid phase of line 157 is cooled in heat exchanger 160. The heat exchanger 160 heats boiler feed water 159 to a medium pressure steam 164, such as an MP steam having a pressure of about 8 bar to about 20 bar, such as about 15 bar. The MP steam 164 is fed to a medium pressure steam header 166 to provide an MP steam stream 168 suitable for dilution steam for furnaces or other medium pressure steam applications. Prior to being cooled in the heat exchanger 160, the liquid phase of line 157 may have a pressure of about 1 bar more than the medium pressure steam header 166 pressure. The medium pressure steam header 166 pressure can be about 7 to about 17 bar. The difference in pressure enables control valve pressure drop for level control in 160 and to offset hydraulic loss in the exchanger and lines.

[0027] It has been discovered that providing boiler feed water 159 to the heat exchanger 160 to exchange heat with the liquid phase of line 157 enables reduced fresh water consumption and minimizes stack temperatures ror a variety of hydrocarbon-contaming feeds, including light crudes. In particular, less fluid from 135 is used to feed into the first sparger 35 of the double sparger assembly 35, 37 to achieve a separation. Conventional furnaces use the heat exchanger 160 to cool separator 153 bottoms stream 157 using cooler feed to the furnace, as show as 131 in FIG. 1. This results in high stack temperatures than the stack temperatures described herein. It has been discovered that supplying high temperature crude at inlet 131 increases stack temperatures and is typically managed by injecting fluids from 135 to the first sparger 35 in order to reduce the temperature of the hydrocarbon stream. Fluids are injected in an amount that provides desired separation while maintaining stack temperatures of about 155°C or lower. Conventional furnaces utilize up to about 4 tons per hour (“tph”) of water to manage stack temperatures.

[0028] It has been discovered that providing hydrocarbon-containing feed directly from the desalter 200 described herein to the inlet 131 of the furnace reduces, or in some cases, eliminates water supplied to the sparger 35, 37. Providing effluent directly from the desalter 200 to the furnace inlet 131 (instead of preheating the desalter effluent in the heat exchanger 160) prior to feeding to the inlet 131 provides a more efficient furnace requiring less sparger water and reducing stack temperatures.

[0029] The desalter 200 effluent temperature can be about 90 °C or less, such as about 70 °C to about 85 °C. Water in an amount of about 2 tph or less is supplied to the sparger 35, 37. The hydrocarbon-containing feed passes through the sparger 35, 37 to be cooled and flue gas passing through the convection section can produce a stack temperatures of about I55°C or lower, such as about 155°C or lower for a heavy crude feed, and/or about 143 °C or lower for a medium crude feed, and/or about 142 °C or lower for a light crude feed.

[0030] The radiant section effluent of line 161 can be conveyed 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 superheater convection section 120, The effluent 176 of the TLE 170 can be provided to tar knock out drum 184 for removal of pyrolysis fuel oil and coke. A tops portion of tar knock out drum 184 is provided to heat exchanger 182 which condenses at least some product vapor (e.g., quench oil vapor) and generates high pressure steam to a high pressure steam header 186. The high pressure steam from the high pressure steam header 186 can be about 30 bar to about 50 bar and can be used to generate electricity from the steam. The electricity can be used to drive large turbines to power refrigeration equipment, can be reintroduced to the furnace to one or more heat recovery exchangers, or a combination thereof. [0031] FIG. 2 depicts a schematic flow diagram of a desalter 200, in accordance with the present disclosure. The desalter 200 includes an effluent interchanger 204 capable of receiving a hydrocarbon-containing feed, such as crude feed from a crude feed tank 202. The effluent from the hydrocarbon-containing feed and desalted effluent interchanger 204 passes to a preheat exchanger 206 to produce a preheated effluent having a temperature of, e.g., about 38 °C to about 95°C, The preheat exchanger 206 receives a hot fluid 208, such as quench oil, quench water, medium pressure steam, or a combination thereof, which is cooled to a cooled fluid 210. The preheated effluent (which was heated by hot fluid 208 in the preheat exchanger 206) is introduced to one or more desalters 212, 214, such as two desalters, to produce desalted effluent. The one or more desalters 212, 214 mix the preheated heated effluent and separate a first phase including the salt and particulates from the desalted effluent. The desalted effluent is provided back to the effluent interchanger 204 and supplied to inlet 131. The desalted effluent includes a reduced amount of salt (e.g., Mg, Ca, Na, Cl, or combinations thereof) and/or particulates relative to the hydrocarbon-containing feed from the crude feed tank 202.

[0032] FIG. 3 depicts a flow diagram of an example method 300 for processing hydrocarbons in accordance with some aspects of the present disclosure. The method 300 can include: introducing 302 a hydrocarbon-containing feed to a desalter preheat trail comprising an effluent interchanger; directing 304 at least a portion of a hydrocarbon-containing feed from a desalter preheat train to a feed inlet of a convection section of a steam cracking furnace; combusting 306 a fuel at a plurality of burners to provide thermal energy to a radiant section and the convection section of the steam cracking furnace; heating 308 the hydrocarbon-containing feed in an operating mode in the convection section to obtain a heated feed mixture; separating 310 a bottoms effluent from the heated feed mixture of the convection section in a separator; and cooling 312 the bottoms effluent in a heat exchanger using boiler feed water.

[0033] The crude feed introduced to the desalter preheat train to be heated can have a temperature of about 60 °C or less. In some embodiments, the hydrocarbon-containing feed is provided to the effluent interchanger before and after introducing the hydrocarbon-containing feed to at least one desalter. A temperature of the portion of the hydrocarbon-containing feed directed to the inlet of the convection section can be desirably controlled at a temperature within about 60 °C or less of a stack temperature of the steam cracking furnace. The hydrocarbon-containmg teed (e.g., effluent from the desalter preheat tram) to the inlet of the convection section can range from, e.g., about 38 °C to about 105 °C. The hydrocarbon- containing feed can be a crude feed, a light crude feed, a heavy crude feed, or a combination thereof. A stack temperature is maintained at a temperature of less than about 150 °C.

[0034] In some embodiments, about 0 tph to about 2 tph of water is introduced to a portion of the convection section of the steam cracking furnace, such as through a sparger 35, 37. The sparger water can be about 35 °C to about 125 °C. The amount of water introduced to the convection section depends on the type of hydrocarbon-containing feed is introduced to the desalter preheat train. For hydrocarbon-containing feed including a heavy crude and/or a medium crude, preferably about 0 tph of water is introduced to the portion of the convection section during the combusting. In some embodiments, the hydrocarbon-containing feed includes a medium crude, a light crude, or a combination of a medium crude and condensate, and the thermal energy provided to the radiant section and the convection section of the steam cracking furnace during the combusting is about 120 MW to about 130 MW. As used herein, a “condensate” has an API gravity greater than 45°. A “light crude” has an API gravity of from 40° to 45°. A “medium crude” lias an API gravity of from 36° to less than 40°. A “heavy crude” has an API gravity’ of less than 36°, preferably from 35° to less than 36°. V aporization in the flash'liquid separator vessel 153 is controlled based on temperature needs of one or more of the lower convection section tube bank 1 19 temperature, stack temperature, SCR bed 180 temperature, and AIG 181 temperature. It has been discovered that heavy crude provides more effluent to the lower convection section tube bank 119, which elevates temperatures relative to lighter crudes. Without being bound by theory, it is believed that the higher temperature of the separator overhead on heavy crudes is the desired separation point to eliminate coking precursor molecules for heavy crudes is higher. For light crudes, smaller trace amounts of these coking precursors can be entrained in to the overhead at a lower temperature, thus, temperature is kept lower on light crudes to prevent coking precursor entrainment in line 119.

[0035] Cooling the bottoms effluent in the heat exchanger 160 using boiler feed water is controlled depending on a type of the hy drocarbon-containing feed and/or a temperature of the bottoms effluent. In some embodiments, cooling the bottoms effluent is used to provide a cooler bottoms effluent for storage, other processing, sale, or combinations thereof. Cooling the bottoms effluent in the heat exchanger using boiler feed water provides a predetermined temperature of a bottom 1/2 height portion of the convection section depending on the coking hydrocarbon-containing feeds, the predetermined temperature is about 350 °C to about 460 °C (e.g., about 415 to about 460 °C for heavy hydrocarbon-containing feeds, such as about 435 °C or less for light hydrocarbon-containing feeds), wherein the bottom 1/2 height portion is disposed between a SCR bed 180 and the radiant section 113 of the furnace. In some embodiments, cooling the bottoms effluent in the heat exchanger using boiler feed water is controlled to provide a predetermined temperature of a SCR bed 180 disposed within the convection section of the furnace. The temperature of the SCR bed 180 inlet is about 325 °C to about 425 °C, such as about 340 °C to about 370 °C. Hie temperature of the bottoms effluent 157 is reduced by about 2.0 °C to about 50 °C in the heat exchanger 160.

[0036] An overhead effluent 155 is separated from the heated feed mixture and introduced to a bottom 1/2 height portion of the convection section. A furnace effluent exiting the radiant section of the furnace is cool ed with boiler feed water to generate steam having a steam pressure of about 50 bar or greater, providing the steam to a steam drum 172, and the steam is introduced to portions of the furnace.

[0037] Boiler feed water 174 can be provided to at least one heat recovery exchanger 171 disposed in an upper 1/2 height portion of the convection section and the boiler feed water can be preheated with the thermal energy supplied by the plurality of burners (not shown). The preheated boiler feed water can be diverted to the steam drum 172.

EXAMPLES

[0038] Table 1 below illustrates the predicted performance of an example furnace of the present disclosure, such as the furnace depicted m FIG. 1 and FIG. 2. The predicted performance is based on simulations. “SoR” means start of run, and “EoR” means end of run.

Table 1. Predicted Performance of an Example Furnace

[0039] As can be seen from the data in Table 1 , lighter feeds result in a reduced transfer of heat to the feed by the heat exchanger 160, enabling a wide variety of feeds. Water injection is only used at the end of the run for light crude in an amount of 2 tph. Water consumption is reduced by about 1 tph to about 4 tph relative to other furnace designs. Additional water consumption is reduced relative to furnaces operating with similar flue stack temperatures. The flue gas stack temperature is shown to be below' 155 °C in all simulations. Moreover, flue gas stack temperature ranges are narrow- comparing each feed type. Conventional furnaces typically show stack temperatures varying by up to 100 °C. In contrast, the flue gas temperatures summarized in Table 1 vary by less than 80 °C, such as about 5 °C to about 20 °C, such as about 10 °C to about 15 °C. The narrow variance of temperature is indicative of feed flexibility with high efficiency. Furnace firing is significantly reduced relative to conventional furnaces, particularly for crude feeds which can use about 155 megawatts or greater of power. In summary; the desalter 200 arrangement and providing the effluent from the desalter to the inlet of the furnace provides an efficient, flexible furnace w-ith reduced consumption of power and water.

[0040] Overall, the methods and systems described herein provide for flexible, sustainable, and efficient cracking of hydrocarbons capable of managing furnace temperatures for flexible hydrocarbon-containing feeds and operating conditions. The furnace incorporates services having certain temperatures to portions of the furnace to exchange temperature between the service and the furnace. An example approach described herein include providing boiler feed water to a heat exchanger to exchange heat, and reduce a temperature of the furnace at a lower 1/2 of the furnace, which subsequently reduces overall fresh water consumption and minimizes stack temperatures for a variety of different hydrocarbon-containing feeds at different operating modes.

Listing of Embodiments

[0041] This disclosure can further include the following non-limiting aspects and/or embodiments:

[0042] Al . A steam cracking process comprising: introducing a hydrocarbon-containing feed to a desalter preheat train comprising an effluent interchanger; directing at least a portion of the hydrocarbon-containing feed from the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace; combusting a fuel at a plurality of burners to provide thermal energy' to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace; and heating the hydrocarbon-containing feed in an operating mode in the convection section to obtain a heated teed mixture, separating a bottoms effluent from the heated feed mixture of the convection section in a separator, cooling the bottoms effluent in a heat exchanger using boiler feed water.

[0043] A2. The process of Al, wherein the hydrocarbon-containing feed is provided to the effluent interchange! before and after introducing the hydrocarbon-containing feed to at least one desalter.

[0044] A3. The process of Al or A2. further comprising controlling a temperature of the portion of the hydrocarbon-containing feed directed to the inlet of the convection section to the temperature and the temperature is within about 60 °C or less of a stack temperature of the steam cracking furnace.

[0045] A4.The process of A3, wherein the hydrocarbon-containing feed from the desalter preheat train to the inlet of the convection is about 85 °C to about 105 °C.

[0046] A5. The process of any of Al to A4, wherein the hydrocarbon-containing feed comprises a crude.

[0047] A6.The process of any of Al to A5, wherein the hydrocarbon-containing feed, when introduced to the desalter preheat train to be heated, has a temperature of about 60 °C or less.

[0048] A7.The process of any of Al to A6, wherein the steam cracking furnace has a stack temperature of less than about 150 °C.

[0049] A8.The process of any of Al to A7, further comprising introducing about 0.1 tph to about 2 tph of water to a portion of the convection section of the steam cracking furnace.

[0050] A9.The process of any of Al to A7, wherein the hydrocarbon-containing feed comprises a heavy crude, a medium crude, or a combination thereof, and water is not introduced to a portion of the convection section during the combusting.

[0051] A10. The process of any of Al to A8, wherein the hydrocarbon-containing feed comprises an intermediate crude, a light crude, or a combination of a medium crude and condensate, and the thermal energy provided to the radiant section and the convection section of the steam cracking furnace during the combusting is about 120 MW to about 130 MW.

[0052] A11. Tire process of any of A1 to Al 0, further comprising diverting steam from the heat exchanger to a steam header.

[0053] A12. The process of All, further comprising providing a dilution steam from the steam header having a pressure of about 8 bar to about 15 bar to the convection section of the furnace.

[0054] A13. The process of All, wherein cooling the bottoms effluent in the heat exchanger using boiler feed water comprises controlling a temperature of the bottoms effluent depending on a type of the hydrocarbon-contaimng feed and/or the temperature of the bottoms effluent.

[0055] A14. The process of A1 1 , wherein cooling the bottoms effluent in the heat exchanger includes providing boiler feed water to the heat exchanger to provide a predetermined temperature of a bottom 1/2 height portion of the convection section, wherein the bottom 1/2 height portion is disposed between aNOx reduction bed and the radiant section of the furnace.

[0056] A15. The process of Al 1, wherein an amount of boiler feed water provided to the heat exchanger is determined based on a predetermined temperature of a NOx reduction bed disposed within the convection section of the furnace.

[0057] Al 6. The process of A13, wherein the bottoms effluent temperature is reduced by about 20 °C to about 50 °C in the heal exchanger.

[0058] A17. The process of any of A1 to A16, further comprising separating an overhead effluent from the heated feed mixture and introducing the overhead effluent to a bottom 1/2 height portion of the convection section.

[0059] A 18. The process of any of A1 to A17, further comprising cooling a furnace effluent exiting the radiant section of the furnace with boiler feed water to generate steam having a steam pressure of about 50 bar or greater , providing the steam to a steam drum and introducing the steam to portions of the furnace.

[0060] A19, The process of Al 8, further comprising introducing the furnace effluent to a knock out drum, condensing a product vapor from the knock out drum in a condenser to steam having a steam pressure of about 30 bar to 50 bar, generating power from the steam, and introducing boiler feed water to the condenser.

[0061] A20. The process of any of A1 to A19, further comprising providing boiler feed water to at least one heat recoveiy exchanger disposed in an upper 1 /2 height portion of the convection section and preheating the boiler feed water with the thermal energy supplied by the plurality of burners.

[0062] A21. The process of A20, further comprising diverting the preheated boiler feed water to a steam drum.

[0063] B1. An apparatus comprising: a steam cracking furnace comprising a convection section and a radiant section; a desalter preheat train coupled to a feed inlet of a convection section of the steam cracking furnace, the desalter preheat train comprising: an effluent interchanger, a trim preheater in fluid communication with the effluent interchanger, and at least one desalter in fluid communication with the trim heater, wherein the at least one desalter is in fluid communication with the effluent interchanger; and a plurality of burners disposed within the steam cracking furnace capable of supplying thermal energy by combusting a fuel. [0064] B2. The apparatus of B1 , further comprising a heat exchanger capable of cooling a boiler feed water, wherein the heat exchanger is capable of diverting a steam to a steam header

[0065 ] B3.The apparatus of B2, further comprising a controller capable of controlling and/or adjusting an amount of the steam diverted to the steam header.

[0066] B4.The apparatus of B2 or B3, wherein the steam header is capable of supplying steam to the convection section of the steam cracking furnace.

[0067] B5.The apparatus of any of B 1 to B4, further comprising a steam drum coupled to and capable of receiving preheated boiler feed water from a heat recovery' exchanger disposed within an upper 1/2 height portion of the convection section of the steam cracking furnace

[0068] B6. The apparatus of any of B1 to B5, further comprising a knock out drum capable of receiving a furnace effluent from the radiant section of the steam cracking furnace.

[0069] B7.The apparatus of B6, further comprising a product vapor cooler in fluid communication with the knock out drum, the product vapor cooler capable of generating steam having a steam pressure of about 50 bar or greater.

[0070] B8.The apparatus of B7, further comprising a steam header capable of providing the steam for one or more applications selected from the group consisting of powering turbines, powering refrigeration, powering compression equipment, and combination(s) thereof,

[0071] C1. A steam cracking process comprising introducing a hydrocarbon-containing feed from a hydrocarbon-feed tank directly to a desalter preheat train; separating a first portion and a second portion of the hydrocarbon-containing feed in the desalter preheat train, wherein separating a first and second portion of the hydrocarbon-containing feed includes: introducing the hydrocarbon-containing feed in an effluent interchanger; preheating the hydrocarbon- containing feed from the effluent interchanger to a trim preheater in fluid communication with the effluent interchanger; separating a first portion and a second portion of the preheated effluent from the trim preheater to at least one desalter in fluid communication with the trim heater, wherein the at least one desalter is in fluid communication with the effluent interchanger; introducing the first portion of the preheated effluent to the effluent interchanger; directing the first portion of the preheated effluent from the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace, and combusting a fuel at a plurality of burners to provide thermal energy to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace. [0072] All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the present disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, it is not intended that the present disclosure be limited thereby. Likewise, the term “comprising” is considered synonymous with the term “including.” Likewise whenever a composition, an element or a group of elements is preceded with the transitional phrase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.

[0073] For the sake of brevity', only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any low'er limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

Claims

CLAIMS What is claimed is:

1. A steam cracking process comprising: introducing a hydrocarbon-containing feed to a desalter preheat tram comprising an effluent interchanger; directing at least a portion of the hydrocarbon-containing feed from the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace; combusting a fuel proximate to a plurality of burners that provide thermal energy to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace; heating the hydrocarbon-containing feed in an operating mode in the convection section to obtain a heated feed mixture; separating a bottoms effluent from the heated feed mixture of the convection section in a separator; and cooling the bottoms effluent in a heat exchanger using boiler feed water.

2. The process of claim 1, wherein the hydrocarbon-containing feed is provided to the effluent interchanger before and after introducing the hydrocarbon-containing feed to at least one desalter.

3. The process of claim 1 or 2, further comprising controlling a temperature of the portion of the hydrocarbon-containing feed directed to the inlet of the convection section to the temperature and the temperature is within about 60 °C or less of a stack temperature of the steam cracking furnace.

4. 'The process of claim 3, wherein the hydrocarbon-containing feed from the desalter preheat train to the inlet of the convection is about 85 °C to about 105 °C.

5. The process of any of claims 1 to 4, wherein the hydrocarbon-containing feed comprises a crude.

6. The process of claim 5, wherein the hydrocarbon-containing feed, when introduced to the desalter preheat train to be heated, has a temperature of about 60 °C or less.

7. The process of any of claims 1 to 6, wherem a stack temperature of the steam cracking furnace is less than about 150 °C.

8. The process of any of claims 1 to 7, further comprising introducing about 0. 1 tph to about 2 tph of water to a portion of the convection section of the steam cracking furnace.

9. The process of any of claims 1 to 7, wherein the hydrocarbon-containing feed conipnses a heavy crude, a medium crude, or a combination thereof, and water is not introduced to the portion of the convection section during the combusting.

10. The process of any of claims 1 to 8, wherein the hydrocarbon-containing feed comprises a medium crude, a light crude, or a combmation of a medium crude and condensate, and the thermal energy provided to the radiant section and the convection section of the steam cracking furnace during the combusting is about 120 MW to about 130 MW.

11. The process of any of claims 1 to 10, further comprising diverting steam from the heat exchanger to a steam header.

12. Tlie process of claim 11, further comprising providing a dilution steam from the steam header having a pressure of about 8 bar to about 15 bar to the convection section of the furnace.

13. The process of claim 11, wherem cooling the bottoms effluent in the heat exchanger using boiler feed water comprises controlling a temperature of the bottoms effluent depending on a type of the hydrocarbon-containing feed and/or the temperature of the bottoms effluent.

14. The process of claim 1 1, wherein cooling the bottoms effluent in the heat exchanger includes providing boiler feed water to the heat exchanger to provide a predetermined temperature of a bottom 1/2 height portion of the convection section, wherein the bottom 1/2 height portion is disposed between a NOx reduction bed and the radiant section of the furnace.

15. The process of claim 11, wherein an amount of boiler feed water provided to the heat exchanger is determined based on a predetermined temperature of a NOx reduction bed disposed within the convection section of the furnace

16. The process of claim 13, wherein the bottoms effluent temperature is reduced by about 20 °C to about 50 °C in the heat exchanger.

17. The process of any of claims 1 to 16, further comprising separating an overhead effluent from the heated feed mixture and introducing the overhead effluent to a bottom 1/2 height portion of the convection section.

18. The process of any of claims 1 to 17, further comprising cooling a furnace effluent exiting the radiant section of the furnace with the boiler feed water to generate steam having a steam pressure of about 50 bar or greater, providing the steam to a steam drum and introducing the steam to portions of the furnace.

19. The process of claim 18, further comprising introducing the furnace effluent to a knock out drum, condensing a product vapor from the brock out drum in a condenser to steam having a steam pressure of about 30 bar to 50 bar, generating power from the steam, and introducing boiler feed water to the condenser

20. The process of any of claims 1 to 19, further comprising providing boiler feed water to at least one heat recovery exchanger disposed in an upper 1/2 height portion of the convection section and preheating the boiler feed water with the thermal energy supplied by the plurality' of burners.

21. The process of claim 20, further comprising diverting the preheated boiler feed water to a steam dram.

22. An apparatus comprising: a steam cracking furnace comprising a convection section and a radiant section; a desalter preheat train coupled to a feed inlet of a convection section of the steam cracking furnace, the desalter preheat train comprising: an effluent interchanger, a trim preheater in fluid communication with the effluent interchanger, and at least one desalter in fluid communication with the trim heater, wherein the at least one desalter is in fluid communication with the effluent interchanger, and a plurality of burners disposed within the steam cracking furnace capable of supplying thermal energy by combusting a fuel.

23. The apparatus of 22, further comprising a heat exchanger capable of cooling a boiler feed water, wherein the heat exchanger is capable of di verting a steam to a steam header.

24. The apparatus of 23, further comprising a controller capable of controlling and/or adjusting an amount of the steam diverted to the steam header.

25. The apparatus of any of claims 22 to 24, further comprising a steam dram coupled to and capable of receiving preheated boiler feed water from a heat recovery exchanger disposed within an upper 1/2 height portion of the convection section of the steam cracking furnace.

26. A steam cracking process comprising introducing a hydrocarbon-containmg feed from a hydrocarbon-feed tank directly to a desalter preheat tram; separating a first portion and a second portion of the hydrocarbon-containmg feed in the desalter preheat tram, wherein separating a first and second portion of the hydrocarbon-containmg feed includes: introducing the hydrocarbon-containmg feed in an effluent interchanger; preheating the hydrocarbon- containing feed from the effluent interchanger to a trim preheater in fluid communication with the effluent interchanger; separating a first portion and a second portion of the preheated effluent from the trim preheater to at least one desalter in fluid communication with the trim heater, wherein the at least one desalter is in fluid communication with the effluent interchanger; introducing the first portion of the preheated effluent to the effluent interchanger; directing the first portion of the preheated effluent from the desalter preheat train to a feed inlet of a convection section of a steam cracking furnace; and combusting a fuel at a plurality of burners to provide thermal energy to a radiant section of the steam cracking furnace and the convection section of the steam cracking furnace.