Low CO2 emission and hydrogen input cracking heater for olefin production

Abstract

The present disclosure provides a process comprising preheating a hydrocarbon feed in a first preheating zone of a convective section, recovering a preheated hydrocarbon stream; heating the preheated hydrocarbon stream in a secondary transfer line exchanger, recovering a heated hydrocarbon stream; feeding the heated hydrocarbon stream to a second preheating zone of the convective section to vaporize a portion of the heated hydrocarbon stream, recovering a cracking feed stream; cracking hydrocarbons in the cracking feed stream in one or more coils in a radiant section, recovering a cracked hydrocarbon product; and cooling the cracked hydrocarbon product in the secondary transfer line exchanger in indirect heat exchange with the preheated hydrocarbon stream, recovering a cooled hydrocarbon product stream.

Description

Technical Field

[0001] Embodiments disclosed herein generally relate to integrated pyrolysis and hydrocracking of hydrocarbon mixtures (such as whole crude oil or other hydrocarbon mixtures) to produce olefins and other chemicals. One of the modes of supplying reaction heat is air heaters. Currently, plants primarily use combustion fuel air heaters that result in emissions associated with combustion. Background Art

[0002] Traditionally, a combustion heater is used to thermally crack hydrocarbon feed to produce ethylene. Similarly, ethane is also cracked to produce ethylene. Although ethane produces a large amount of hydrogen, after meeting the requirements for acetylene hydrogenation (to produce additional ethylene) and methylacetylene and propadiene (MAPD) ​​hydrogenation, excess hydrogen is generally not enough to meet the heat demand in traditional cracking heaters. This results in the need to add additional methane or other hydrocarbons to the fuel gas mixture. Any additional hydrocarbons burned produce CO2, and thus cause CO2 emissions.

[0003] Currently, cracking heaters use fossil fuel combustion to meet the process load requirements. The process load is the load required for the cracking reaction as well as evaporating the feed and preheating the feed and dilution steam. This constitutes the heat of reaction and sensible heat. A portion of the sensible heat and excess energy in the flue gas is recovered as high-pressure steam and preheated boiler feed water. Since a large amount of steam is generated and a portion of it is used for superheating steam and preheating boiler feed water, the fuel consumption is high.

[0004] To reduce CO2 emissions in heaters, one method proposed in the prior art is to use air preheating or preheating the fuel. When air preheating is used in conjunction with conventional heater designs, the super high pressure (SHP) steam production is high and therefore the reduction in fuel consumption is small. Summary of the invention

[0005] An integrated pyrolysis and hydrocracking process has been developed for the flexible processing of whole crude oil and other hydrocarbon mixtures containing high boiling point coke precursors. Embodiments herein can advantageously reduce the capital and energy requirements associated with operating an integrated pyrolysis and hydrocracking unit.

[0006] In one aspect, embodiments disclosed herein relate to an integrated pyrolysis and hydrocracking process for converting a hydrocarbon mixture to produce olefins. The process includes preheating a hydrocarbon feed in a first preheating zone of a convection section, recovering a preheated hydrocarbon stream; heating the preheated hydrocarbon stream in a secondary transmission line exchanger, recovering a heated hydrocarbon stream; supplying the heated hydrocarbon stream to a second preheating zone of the convection section to vaporize a portion of the heated hydrocarbon stream, recovering a cracked feed stream; cracking hydrocarbons in the cracked feed stream in one or more coils in a radiant section, recovering cracked hydrocarbon products; and cooling the cracked hydrocarbon products in indirect heat exchange with the preheated hydrocarbon stream in the secondary transmission line exchanger, recovering a cooled hydrocarbon product stream.

[0007] In another aspect, embodiments disclosed herein relate to an integrated pyrolysis and hydrocracking system for converting a hydrocarbon mixture to produce olefins. The system includes a pyrolysis heater including a convection heating zone and a radiant heating zone; a first preheating zone in the convection zone, the first preheating zone configured to preheat the hydrocarbon mixture and recover a preheated hydrocarbon stream; a secondary transmission line exchanger, the secondary transmission line exchanger configured to heat the preheated hydrocarbon stream and recover the heated hydrocarbon stream; a second preheating zone in the convection zone, the second preheating zone configured to vaporize a portion of the heated hydrocarbon stream and recover a cracked feed stream; one or more coils in the radiant zone, the one or more coils configured to crack hydrocarbons in the cracked feed stream and recover cracked hydrocarbon products; and a feed line for directing the cracked hydrocarbon products to the secondary transmission line exchanger for cooling in indirect heat exchange with the preheated hydrocarbon stream, recovering a cooled hydrocarbon product stream.

[0008] The process flow diagrams shown in the attached schematics may be slightly modified for specific crude oils and product compositions.Other aspects and advantages will become apparent from the following description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A simplified process flow diagram illustrating systems and processes according to one or more embodiments disclosed herein.

[0010] Figure 2 A simplified process flow diagram illustrating systems and processes according to one or more embodiments disclosed herein. DETAILED DESCRIPTION

[0011] Embodiments disclosed herein generally relate to pyrolysis and hydrocracking of hydrocarbon mixtures, such as whole crude oil or other hydrocarbon mixtures, to produce olefins, such as ethylene.

[0012] Hydrocarbon mixtures useful in the embodiments disclosed herein may include various hydrocarbon mixtures having a boiling point range, wherein the final boiling point of the mixture may be greater than 450° C. or greater than 500° C., such as greater than 525° C., 550° C., or 575° C. The amount of high boiling hydrocarbons (such as hydrocarbons with a boiling point exceeding 550° C.) may be as low as 0.1 wt%, 1 wt%, or 2 wt%, but may be as high as 10 wt%, 25 wt%, 50 wt%, or greater. The process disclosed herein may be applied to crude oils, condensates, and hydrocarbons having a broad boiling point curve and an end point above 500° C. Such hydrocarbon mixtures may include whole crude oil, virgin crude oil, hydrotreated crude oil, gas oil, vacuum gas oil, heating oil, jet fuel, diesel, kerosene, gasoline, synthetic naphtha, raffinate reformate, Fischer-Tropsch liquids, Fischer-Tropsch gases, natural gas, gasoline, distillates, virgin naphtha, natural gas condensate, atmospheric pipeline distillation bottoms, vacuum pipeline distillation streams including bottoms, wide boiling range naphtha to gas oil condensate, heavy non-virgin hydrocarbon streams from refineries, vacuum gas oil, heavy gas oil, atmospheric residue, hydrocracked wax, and Fischer-Tropsch wax, etc. In some embodiments, hydrocarbon mixtures may include hydrocarbons with boiling points ranging from naphtha range or lighter to vacuum gas oil range or heavier. If desired, these feeds may be pretreated to remove sulfur, nitrogen, metals, and a portion of Conradson carbon upstream of the processes disclosed herein. Lighter hydrocarbon feeds, such as ethane, propane, butane, etc., and mixtures of various of these different lighter hydrocarbons may also be used as feedstocks to the cracking furnaces herein.

[0013] Thermal cracking reactions proceed via a free radical mechanism. Therefore, high ethylene yields can be achieved when hydrocarbons are cracked at high temperatures. Lighter feeds, such as butane and pentane, require high reactor temperatures to obtain high olefin yields. Heavier feedstocks, such as gas oil and vacuum gas oil (VGO), require lower temperatures. Crude oil contains a distribution of compounds from butane to VGO and residues (e.g., materials with normal boiling points exceeding 520°C).

[0014] Many countries require the reduction of CO2 emissions. When fossil fuels are burned to supply energy, CO2 production is usually high. The embodiments disclosed herein are intended to reduce fuel consumption for the same process load by efficiently designing the heater. In conventional processes, excess enthalpy in flue gas is used to generate high pressure steam. This can reduce steam generation and only use the heat energy available in the fuel for the process load. In doing so, the heater can reduce or eliminate CO2 generation and H2 input.

[0015] Current heater designs are based on producing as much steam as possible to meet the olefin plant energy needs to drive the turbine. This results in more fuel being burned in the cracking heater. The embodiments disclosed herein are intended to reduce fuel consumption by redesigning the heater to improve fuel efficiency and produce less steam. This reduces carbon dioxide emissions in the heater, which is the main source of CO2 emissions in ethylene plants. In some embodiments, ethane cracking also produces a large amount of hydrogen, but this amount is not enough to meet the combustion needs. In order to achieve zero CO2 emissions, additional H2 must be input. Therefore, the disclosed embodiments relate to a heater design that requires zero H2 input and still produces zero or low CO2 emissions.

[0016] To reduce CO2 emissions in heaters, one approach proposed in the prior art is to use air preheating or preheating the fuel. When air preheating is used in conjunction with conventional heater designs, the production of super high pressure (SHP) steam is high and therefore the reduction in fuel consumption is small. An alternative heater design is proposed to use an exchanger to first heat the process fluid and then heat the residual energy to generate SHP steam to quench the hot effluent.

[0017] The embodiments disclosed herein use the convection section of the pyrolysis reactor (or heater) to preheat the feed hydrocarbon mixture and separate it into various fractions. Steam can be injected at appropriate locations to increase the evaporation of the hydrocarbon mixture and to control the degree of heating and separation. The evaporation of the hydrocarbons occurs at relatively low temperatures and / or adiabatically, so that coking in the convection section will be suppressed.

[0018] For mixed feeds, such as crude oil or other hydrocarbon mixtures with high boiling temperature components, the convection section can therefore be used to heat the entire hydrocarbon mixture to form a vapor-liquid mixture. The gaseous hydrocarbons will then be separated from the liquid hydrocarbons, and only the separated vapors will be fed to the radiant coils in one or more radiant sections of a single heater. For lighter mixtures or single component feeds, such as ethane feeds, separation of unvaporized hydrocarbons may not be necessary. The radiant coil geometry can be of any type. For the desired feed hydrocarbon vapor mixture and reaction intensity, the optimal resident radiant coil can be selected to maximize olefins and run length.

[0019] Multiple heating steps may be used to heat the hydrocarbons to the desired temperature. This will allow for optimal cracking so that flux, steam to oil ratio, heater inlet and outlet temperatures, and other variables can be controlled at desired levels to achieve desired reaction results, such as achieving a desired product distribution while limiting coking in the radiant coils and associated downstream equipment.

[0020] The process of hydrocarbon cracking in a pyrolysis reactor can be divided into three parts, namely a convection section, a radiation section and a quench section, such as in a transport line exchanger (TLE). In the convection section, the feed is preheated, partially evaporated and mixed with steam. In the radiation section, the feed is cracked (the main cracking reaction occurs here). In the TLE, the reaction fluid is quickly quenched to stop the reaction and control the product mixture. In addition to indirect quenching via heat exchange, direct quenching using oil is also acceptable.

[0021] The embodiments herein efficiently utilize the convection section to enhance the cracking process. In some embodiments, all heating can be performed in the convection section of a single pyrolysis reactor. In other embodiments, separate heaters can be used for each fraction. In some embodiments, the hydrocarbon feed enters the top row of the convection tube bundle and is preheated to a medium temperature at the operating pressure using the hot flue gas generated in the radiant section of the heater without adding any steam. The outlet temperature can range from 150°C to 400°C, depending on the hydrocarbon feed and flux. Under these conditions, 5% to 70% (volume) of crude oil may evaporate. For example, the outlet temperature of the first heating step can evaporate naphtha (with a normal boiling point of up to about 200°C). Other fractionation limits (end points) can also be used, such as 350°C (gas oil), etc. Since the hydrocarbon mixture is preheated using the hot flue gas generated in the radiant section of the heater, limited temperature changes and flexibility in the outlet temperature can be expected.

[0022] After cracking in the radiant coil, one or more transmission line exchangers (TLEs) can be used to cool the product very quickly and generate steam. One or more coils can be combined and connected to one or more TLEs. The TLE can be a double tube or multi-tube shell and shell exchanger. Embodiments disclosed herein are directed to TLEs that reduce SHP steam production and therefore reduce CO2 generation and H2 input requirements.

[0023] In one or more embodiments, the maximum fuel energy can be transferred to heat the reaction mixture and initiate the reaction. Only when the effluent mixture is rapidly quenched after the reaction, the olefin selectivity may be high. A method of rapidly quenching the reaction and stopping olefin production is to directly quench the effluent using a cold fluid. As a cold fluid, water, oil or steam can be used. Due to the low coil outlet pressure, low-pressure steam or medium-pressure steam can also be used. When using indirect quenching, a small TLE can be used and a minimum amount of steam may be required. In such an embodiment, the temperature can be reduced to a sufficient level so that the reaction rate is rapidly reduced and the effluent mixture is still hot enough to preheat the reaction mixture using one or more downstream exchangers. Since the TLE may be small, the SHP steam production may be low. Due to the reduction in SHP steam production, the convection section can be modified to flexibly adapt to different feeds and operating modes. The same convection section can also work during decoking and high steam conditions.

[0024] Reference now Figure 1 , showing a simplified flow diagram of the above-described embodiment. A fired tube furnace 100 is used to crack hydrocarbons in a hydrocarbon feed stream 10 into ethylene and other olefinic compounds. The fired tube furnace 100 has a convection section or region 110 and a radiant section or region 120. The furnace contains one or more process tubes (radiant coils) 122 through which a portion of the hydrocarbons supplied through the hydrocarbon feed line 10 are cracked upon application of heat to produce product gases. Radiant and convective heat is supplied by the combustion of a heating medium which is introduced into the radiant section 120 of the furnace through a plurality of burner nozzles 124 (such as floor burners, floor burners, or wall burners) and exits through an exhaust port located at the top of the furnace.

[0025] Downstream of the radiant section 120 are the primary TLE 130 and the secondary TLE 140. At the top of the convection section 110, air 12 is fed into an air preheater region (APH) 150 to preheat the air to be used in the burners 124 in the radiant section 120. In the convection section 110, the hydrocarbon stream 10 is preheated in a first preheating region and superheated in a second preheating region before entering the radiant section 120. In the radiant section 120, cracking reactions proceed to produce the desired products. Fuel consumption is entirely determined by the radiant section 120 through burners on the bottom end of the radiant section 120, on the wall of the radiant section 120, or on both. The preheated air 14 is used in one or more of the radiant section burners 124. The hydrocarbon stream 10 is mixed with dilution steam 16 and heated and combined in the convection section 110 to form a mixed stream A. Mixed stream A can then be fed to a secondary TLE 140 where it is further heated in opposition to the product olefins 20 being cooled. The heated mixed stream B is then fed to the convection section 110 for additional heating. After a second pass through the convection section 110, the heated mixed stream 18 is then fed to the radiant section 120 for cracking to produce olefins such as ethylene. The cracked product leaving the radiant section is then fed to the primary TLE 130 for rapid quenching. A portion of the cooled product mixture 20 is then fed to the secondary TLE 140 for additional cooling and preheating of the hydrocarbon feed stream and steam mixture (mixed stream A).

[0026] If the reaction load is minimized to convert only the feed into the product, the fuel consumption of the radiation section 120 can be reduced. This can be achieved by supplying the feedstock at a high inlet temperature. After the radiation section 120, in order to retain the olefins, the reaction mixture can be quickly quenched. This can be done in two ways. Use a quenching liquid such as water, steam or oil for direct quenching. Alternatively, indirect quenching can be used. By indirect quenching, high-pressure steam is generated. The reaction mixture will enter the tube side (or shell side) of the primary TLE 130. The other side of the primary TLE 130 will generate steam 22 through the boiler feed steam generation system 160. Since the generated steam has a very high heat transfer coefficient, the mixture can be quickly quenched in a short distance in the primary TLE 130. Typically, the radiation coil outlet temperature will be 750°C to 950°C, depending on the feed and coil design. The product mixture is cooled to 300°C to 450°C at the beginning of the run and it may reach 500°C to 650°C at the end of the run. Most cracking reactions stop at around 650°C and therefore the primary TLE 130 (the first exchanger for rapid quenching of the fluid) is designed to reach a high start-up operating outlet temperature (approximately 600°C). This will only produce a small amount of SHP steam. As a result, the convection section 110 does not need to superheat a large amount of SHP steam and thereby saves energy in steam superheating. By generating only a small amount of SHP steam, the energy in the steam is transferred to the process fluid for improved cracking performance. This can significantly reduce the heating load and thereby reduce fuel consumption and CO2 production.

[0027] Typically, the heater height is 20ft to 50ft using both floor burners and wall burners or using only floor burners or using only wall burners. By using only floor burners, the radiation efficiency can be further improved. Short flame floor burners are also used, and the radiation heat intensity is high at the bottom. High hydrogen-containing fuels naturally improve the radiation efficiency. All these factors can reduce fuel consumption and therefore reduce the CO2 produced in the flue gas. A secondary TLE 140 for process heating can also be used. In the secondary TLE 140, the process fluid (hydrocarbons and dilution steam) is heated. Depending on the feed, the effluent outlet temperature can be from 190°C to 400°C. In one or more embodiments, a portion of the combined feed hydrocarbons and dilution steam can bypass the secondary TLE 140 and thereby control the outlet temperature in the case of severe fouling that may be expected. When the outlet temperature is relatively high, both the primary TLE 130 (the first exchanger that generates steam) and the secondary TLE 140 can be cleaned online. The optimal primary / secondary distribution depends on the feed. In any case, the primary TLE will operate at a high temperature generating only a small amount of steam.

[0028] In one or more embodiments, a modified layout of a small primary TLE for SHP steam generation followed by a large secondary TLE for reaction mixture preheating and a convection section with air preheating at the top gives the greatest benefit in reducing fuel consumption and thereby reducing CO2 emissions from the heaters. It is contemplated to use a common secondary TLE for many heaters throughout the plant for a single feed. In such embodiments, the spare TLE increases the time on process flow.

[0029] Alternatively (not shown here), after the primary TLE and the resulting hot stream is exchanged with preheated air, the effluent can be cooled by generating low-pressure steam, medium-pressure steam or high-pressure steam.

[0030] Table 1 shows the heat of reaction and sensible heat for different feeds. The heat of reaction is the minimum amount of heat required for the reaction. The additional load is the sensible heat recovered as steam or process preheat. It is desirable to minimize the sensible heat without significant reaction in the convection section by increasing the feed inlet temperature to the limit possible. In the table, the percentage of reaction load (kcal / kg HC) to the radiation box (or radiation load) is expressed as "%".

[0031] Table 1

[0032]

[0033] If contaminated feeds or high boiling feeds such as VGO or HVGO are used, fouling in the secondary TLE is possible. When the shell side must be cleaned, mechanical cleaning can be used. Alternatively, steam / air cleaning can be used. For this purpose, air is heated in the convection section and sent to the shell side.

[0034] In some embodiments, HVGO cracking may be required. In such embodiments, the shell side of the secondary TLE may contain droplets or liquid (two-phase flow) and this may cause scaling during evaporation. Since the heat balance may not allow the HVGO to be completely evaporated at the inlet after mixing with the dilution steam, two-phase flow may occur. For such embodiments, instead of HVGO+dilution steam entering the shell side of the secondary TLE, only dilution steam will enter. This dilution steam mixes with the hot HVGO feed at the outlet of the secondary TLE and is then superheated in the convection section as usual. This can avoid any coking in the shell side of the secondary TLE.

[0035] In other embodiments, dilution steam may be supplied to the secondary TLE. In these embodiments, the heating load in the convection section may be reduced, thereby reducing the amount of H2 required for combustion.

[0036] Reference now Figure 2 , shows an embodiment with dilution steam 16 being supplied to the secondary TLE 140. Figure 1 Similarly, the air 12 is preheated in the APH section 150 at the top of the convection section to improve efficiency during combustion. The hydrocarbon stream 10 is preheated in the convection section 110 and fed to the secondary TLE 140 along with the dilution steam 16 for additional heating. The hot combined hydrocarbons and dilution steam are then fed back to the convection section 110 for additional heating. The heated hydrocarbons and dilution steam 18 are then fed to the radiant section for cracking. The olefin products are then fed to the primary TLE 130 for quenching, similar to Figure 1 .

[0037] In such an embodiment, the amount of hydrogen produced in the plant by ethane cracking can be used in the burners in the radiant section. However, the hydrogen may not be recovered as a hydrogen product for H2 fuel. More than 90% of the hydrogen produced after meeting the acetylene and MAPD hydrogenation amounts can be recovered as a product. Only this amount of hydrogen can be used as a fuel for combustion in the cracking heater. Based on the available hydrogen after meeting the hydrogenation requirements, only excess hydrogen is burned as fuel in the heater. The radiation efficiency can be improved by increasing the air preheating temperature and also by increasing the fuel preheating temperature. All the energy available for feed heating and also for preheating air is limited by the energy available in the flue gas. Therefore, the process fluid (ethane and dilution steam (DS)) can only obtain the maximum amount of energy when the minimum amount of SHP is overheated. This means that the minimum amount of SHP must be produced. This can be achieved by a short primary TLE that generates SHP steam after the radiation coil.

[0038] Table 2 shows the overall material balance for the 1000 KTA plant operating for 8400 hours.

[0039] Table 2

[0040]

[0041] Table 3 shows the performance of a single heater where 100% of the available H2 is used for combustion and additional heating via the electric furnace.

[0042] Table 3

[0043]

[0044]

[0045] The above examples demonstrate that the cracking heater can be designed to burn 100% hydrogen and if necessary, additional load can be provided by electricity. The electrical heating is done at relatively low temperatures. There are some medium to low temperature heat sources such as quench water, boiler feed water and LP steam available on the process side (recovery section). Some air is preheated by flue gases in the convection section and only the remaining load is supplied by electricity. In other embodiments, the fuel source, such as hydrogen, can also be preheated by the power supply, thereby reducing emissions. By changing the APH temperature, H2 combustion can be further reduced. Fuel can be further reduced by superheating the dilution steam and / or ethane + dilution steam mixture by electrical heating. The electrical demand for one heater is about 6MW. Electricity can be generated from non-fossil energy to reduce the overall net H2 usage and overall CO2 emissions of the cracker.

[0046] Unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which these systems, apparatuses, methods, processes, and compositions belong.

[0047] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0048] As used herein and in the appended claims, the words "comprising," "having," and "including" and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps.

[0049] "Optionally" means that the subsequently described event or circumstance may or may not occur. The description includes instances where the event or circumstance occurs and instances where the event or circumstance does not occur.

[0050] When the word "about" or "approximately" is used, the term may mean that the value may vary by up to ±10%, up to 5%, up to 2%, up to 1%, up to 0.5%, up to 0.1%, or up to 0.01%.

[0051] Ranges can be expressed as from about one particular value to about another particular value, inclusive. When such a range is expressed, it should be understood that another embodiment is from the one particular value to the other particular value, as well as all the particular values ​​within the range and combinations thereof.

[0052] While the present disclosure includes a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the present disclosure. Accordingly, the scope should be limited only by the appended claims.

Claims

1. An integrated pyrolysis and hydrocracking process for converting a hydrocarbon mixture to produce olefins, the process comprising: preheating a hydrocarbon feed in a first preheating zone of the convection section and recovering a preheated hydrocarbon stream; heating the preheated hydrocarbon stream in a secondary transfer line exchanger and recovering the heated hydrocarbon stream; feeding the heated hydrocarbon stream to a second preheating zone of the convection section to vaporize a portion of the heated hydrocarbon stream and recover a cracked feed stream; cracking hydrocarbons in the cracked feed stream in one or more coils in the radiant section and recovering cracked hydrocarbon products; and The cracked hydrocarbon product is cooled in indirect heat exchange with the preheated hydrocarbon stream in the secondary transfer line exchanger and a cooled hydrocarbon product stream is recovered.

2. The process of claim 1 further comprising supplying a dilution steam flow to the first preheating zone of the convection section and mixing the dilution steam flow with the hydrocarbon feed to produce the preheated hydrocarbon flow.

3. The process of claim 1 or claim 2, further comprising: mixing a dilution steam stream with the preheated hydrocarbon stream to produce a mixed hydrocarbon-steam stream; and The mixed hydrocarbon-steam stream is fed to the secondary transfer line exchanger and the heated hydrocarbon stream is recovered.

4. The process according to any one of claims 1 to 3, further comprising: supplying an air flow to a third preheating zone of the convection section; recovering the preheated air stream; and The preheated air stream is supplied to the radiant section, wherein the preheated air stream reduces an amount of fuel required to crack hydrocarbons in the one or more coils in the radiant section.

5. The process according to any one of claims 1 to 4, further comprising: The cracked hydrocarbon product is quenched in a primary transfer line exchanger located upstream of the secondary transfer line exchanger.

6. The process of any one of claims 1 to 5, further comprising feeding the cooled hydrocarbon product stream to a downstream recovery process.

7. An integrated pyrolysis and hydrocracking system for converting a hydrocarbon mixture to produce olefins, the system comprising: a pyrolysis heater, the pyrolysis heater comprising a convection heating region and a radiation heating region; a first preheating zone of the convection heating zone, the first preheating zone configured to preheat a hydrocarbon feed and recover a preheated hydrocarbon stream; a secondary transfer line exchanger configured to heat the preheated hydrocarbon stream and recover a heated hydrocarbon stream; a second preheating zone of the convection heating zone, the second preheating zone configured to vaporize a portion of the heated hydrocarbon stream and recover a cracked feed stream; one or more coils in the radiant heating zone, the one or more coils configured to crack hydrocarbons in the cracked feed stream and recover cracked hydrocarbon products; as well as A feed line for directing the cracked hydrocarbon product to the secondary transfer line exchanger for cooling in indirect heat exchange with the preheated hydrocarbon stream, recovering a cooled hydrocarbon product stream.

8. The system of claim 7, further comprising: a dilution steam flow inlet configured to provide a dilution steam flow to the first preheating zone of the convection heating zone; and a mixer configured to mix the dilution steam flow with the hydrocarbon feed to produce the preheated hydrocarbon flow.

9. The system according to claim 7 or claim 8, further comprising: a mixer configured to mix a dilution steam flow with the preheated hydrocarbon flow to produce a mixed hydrocarbon-steam flow; as well as A mixed feed inlet is configured to supply the mixed hydrocarbon-steam stream to the secondary transfer line exchanger.

10. The system according to any one of claims 7 to 9, further comprising: a third preheating zone of the convection heating zone, the third preheating zone configured to receive an air flow and heat the air flow to produce a preheated air flow; as well as A secondary feed line is configured to supply the preheated air flow to the radiant heating zone, wherein the preheated air flow reduces an amount of fuel required to crack hydrocarbons in the one or more coils in the radiant heating zone.

11. The system according to any one of claims 7 to 10, further comprising: A primary transfer line exchanger is positioned upstream of the secondary transfer line exchanger, the primary transfer line exchanger being configured to quench the cracked hydrocarbon product.

12. The system of any one of claims 7 to 11, further comprising a product outlet configured to recover the cooled hydrocarbon product stream and feed it to a downstream recovery process.

13. The system of any one of claims 7 to 12, further comprising an electric heater configured to heat or preheat one or more of an air stream, the hydrocarbon feed, water, hydrogen, or steam.

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