CN113801683A - Electric heating ethylene cracking furnace device - Google Patents

Electric heating ethylene cracking furnace device Download PDF

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Publication number
CN113801683A
CN113801683A CN202111100813.4A CN202111100813A CN113801683A CN 113801683 A CN113801683 A CN 113801683A CN 202111100813 A CN202111100813 A CN 202111100813A CN 113801683 A CN113801683 A CN 113801683A
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China
Prior art keywords
gas
circulating gas
cracking furnace
furnace
electric heating
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CN202111100813.4A
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Chinese (zh)
Inventor
张磊
李保有
詹爽
薄建民
卢永生
桑龙
张娣
赵旭
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Wison Engineering Ltd
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Wison Engineering Ltd
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Priority to CN202111100813.4A priority Critical patent/CN113801683A/en
Publication of CN113801683A publication Critical patent/CN113801683A/en
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
    • C10G9/18—Apparatus
    • C10G9/20—Tube furnaces
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
    • C07C4/02—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
    • C07C4/04—Thermal processes
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/62—Heating elements specially adapted for furnaces
    • H05B3/64—Heating elements specially adapted for furnaces using ribbon, rod, or wire heater
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P30/00—Technologies relating to oil refining and petrochemical industry

Abstract

The invention provides an electric heating ethylene cracking furnace device, which belongs to the technical field of ethylene production equipment in the petrochemical industry, and comprises: cracking furnace and circulating gas circuit. The cracking furnace at least comprises a furnace body, a radiation coil, an electric heating element and a heat exchange tube bundle, wherein the radiation coil, the electric heating element and the heat exchange tube bundle are arranged in the furnace body, the circulating gas path and the furnace body form a closed loop, and the electric heating element is used for transferring heat required by a cracking reaction to process fluid in the radiation coil tube and heating circulating gas in the furnace body. The circulating gas is used as a heat carrier to bring heat to the heat exchange tube bundle, and the heat is recycled through the heat exchange tube bundle. The invention provides heat for the cracking furnace in an electric heating way without generating greenhouse gases andnitrogen Oxides (NO)X) And the like. The heat-carrying gas in the furnace is recycled, and the thermal efficiency of the cracking furnace is up to more than 98%. The invention has small change amount of electric heating for the traditional fuel combustion type cracking furnace, and is economical and practical.

Description

Electric heating ethylene cracking furnace device
Technical Field
The invention relates to an electric heating ethylene cracking furnace device, and belongs to the technical field of ethylene production equipment in the petrochemical industry.
Background
The traditional ethylene cracking furnace is an open flame reactor used for cracking different raw materials in an ethylene device in a heating mode, and is a tap of the ethylene device. The cracking furnace is divided into a radiation chamber and a convection chamber. The radiation chamber is a part for performing radiation heat transfer by high-temperature flue gas generated by fuel combustion, and the temperature of the hearth is about 1100-1400 ℃. The radiation coil is suspended in the radiation chamber, and the cracking reaction is carried out in the radiation coil. The high-temperature flue gas enters the convection chamber from the radiation chamber and carries out heat convection with the tube bundle in the convection chamber. A plurality of groups of heat exchange tube bundles for preheating raw materials and recovering heat are distributed in the convection chamber, and the heat exchange tube bundles comprise a raw material preheating section, a boiler feed water preheating section, a mixed material preheating section, a dilution steam superheating section, a high-pressure steam superheating section and the like.
The cracking furnace is the main energy consumption equipment of the ethylene device, and the energy consumption of the cracking furnace accounts for more than 60 percent of the total energy consumption of the device. The cracking reaction requires the absorption of a large amount of heat. The existing ethylene cracking furnace mainly uses combustion fuel gas or fuel oil to provide heat, and a large amount of greenhouse gases and harmful gas pollutants are released in the combustion process. In order to respond to the national targets of carbon peak reaching and carbon neutralization, the industrial technology upgrading of the ethylene cracking process is imperative.
Patent CN1315489A discloses an electrically heated cracking furnace. The cracking furnace body consists of a fixed furnace body and a movable furnace body, and the temperature in the furnace is flexibly and conveniently controlled and adjusted by means of arranging a plurality of furnace tiles in the vertical direction, arranging spacing bars and the like; and can detect out the trouble position of pyrolysis furnace fast accurately when carrying out the maintenance to pyrolysis furnace inside to maintain.
Patent CN204151291U discloses an ethylene cracking furnace. The pyrolysis furnace includes the pyrolysis tube that sets up in the furnace body, and the resistance wire has been laid outward to the pipe wall of pyrolysis tube, and the pyrolysis tube both ends are equipped with feed inlet and discharge gate respectively, and the pyrolysis tube is parallel to each other between at least two and each pyrolysis tube, and the resistance wire interlude sets up between each pyrolysis tube. The resistance wire heating technology is adopted to improve the ethylene cracking furnace.
Patent CN204803268U discloses an ethylene cracking furnace, which comprises a cracking furnace radiation chamber, wherein the shape of the inner section of the cracking furnace radiation chamber is a continuous concave structure with the position facing to the left side or the right side, and the inside of the continuous concave structure is a communicated cavity structure; meanwhile, a plurality of heat radiation elements are arranged on the wall of the cavity; the heat radiation element is a radiation electric heating plate which is connected with the cavity wall in a sticking way; the bottom surface of each leftward or rightward concave surface in the continuous concave surface structure is an inclined surface which is inclined downwards in the opposite direction of the concave surface. And the continuous groove and the inclined plane structure are utilized, so that the raw material is heated uniformly in the cracking process.
The electric heating ethylene cracking furnace in the prior art is not researched much, and the industrial application is not realized. Aiming at the characteristics of industrial operation of the ethylene cracking furnace, a high-efficiency and reliable electric heating mode is adopted, and reasonable process and structural design are carried out, so that the ethylene cracking furnace is suitable for large-scale application and becomes a key problem in the technical development of the electric heating ethylene cracking furnace.
Disclosure of Invention
In view of the above-mentioned disadvantages of the prior art, it is an object of the present invention to provide an electrically heated ethylene cracking furnace apparatus which does not generate harmful pollutants such as greenhouse gases and nitrogen oxides and which improves the thermal efficiency of the cracking furnace.
The utility model belongs to the technical field of ethylene production equipment in petrochemical industry, and a cracking furnace processes a mixture of raw materials and steam into cracking gas rich in target products such as ethylene/propylene in an electric heating mode. The device specifically comprises a cracking furnace and a circulating gas path which forms closed circulation with the inside of the cracking furnace. The cracking furnace is internally provided with a radiation coil and an electric heating element. When the furnace is operated, the power supply of the electric heating element is switched on, the electric heating element generates heat and mainly transfers heat required by cracking reaction to the radiation coil in a heat radiation mode, and meanwhile, circulating gas in the furnace is heated. Circulating gas is circulated in the hearth to be used as a heat carrier, and the heat in the radiation chamber is taken out for recycling. Specifically, the ethylene cracking furnace comprises a radiation chamber and a convection chamber, wherein a radiation coil is arranged in the radiation chamber, a heat exchange tube bundle is arranged in the convection chamber, and heat of the radiation chamber is transferred to the heat exchange tube bundle of the convection chamber through circulating gas to be recycled. And circulating gas after heat exchange flows out of a circulating gas outlet of the convection chamber, enters a circulating gas path for external circulation, and finally returns to the cracking furnace through a circulating gas inlet of the radiation chamber for reheating and utilization.
There are three options for displacement gas: 1) the replacement gas is protective gas such as nitrogen or inert gas, so that the cracking furnace is in non-oxidizing atmosphere; 2) the replacement gas is carbon dioxide and/or water vapor to enhance radiation heat transfer; 3) the displacement gas is a mixture of the above protective gases, carbon dioxide and/or water vapor.
The circulating gas may be air or may be replaced with a replacement gas.
The invention provides an electric heating ethylene cracking furnace device, which comprises: a cracking furnace and a circulating gas circuit;
the cracking furnace at least comprises a furnace body, a radiation coil, an electric heating element and a heat exchange tube bundle, wherein the radiation coil, the electric heating element and the heat exchange tube bundle are arranged in the furnace body;
the furnace body is provided with a circulating gas inlet and a circulating gas outlet, and two ends of the circulating gas path are respectively communicated with the circulating gas inlet and the circulating gas outlet;
the circulating gas circuit and the furnace body form a closed loop which is used as a channel for circulating gas to flow;
the electric heating element is used for transferring heat required by cracking reaction to the in-pipe process fluid of the radiation coil and providing heat of circulating gas in the furnace body; the heat exchange tube bundle is used for recovering heat of the circulating gas.
In some embodiments of the invention, the furnace body further comprises a radiant chamber and a convection chamber in communication with each other;
the radiant coil is arranged in the radiant chamber, and the heat exchange tube bundle is arranged in the convection chamber;
the circulating gas inlet is arranged in the radiation chamber, and the circulating gas outlet is arranged in the convection chamber;
the circulation gas is used to transfer the heat obtained in the radiant chamber to the heat exchanger bundle.
In some embodiments of the invention, the recycle gas inlet is disposed in the radiant chamber and upstream of the flow direction of the recycle gas in the cracking furnace;
and/or the circulating gas outlet is arranged in the convection chamber and is positioned at the downstream of the circulating gas flowing direction in the cracking furnace.
In some embodiments of the invention, one or more of the radiation chambers are provided;
and/or one or more circulating gas inlets are arranged;
and/or one or more circulating gas outlets are arranged.
In some embodiments of the invention, the furnace body and/or the circulating gas circuit is provided with a replacement gas inlet and a replacement gas outlet;
the replacement gas inlet is used for introducing replacement gas; the replacement gas outlet is used for discharging replaced gas in the furnace body;
preferably, the displacement gas is selected from one or more of nitrogen, an inert gas, carbon dioxide or water vapour.
In some embodiments of the invention, one or more of the replacement gas inlets are provided;
and/or one or more displacement gas outlets are arranged.
In some embodiments of the present invention, the circulating gas circuit further comprises a gas conveying mechanism;
the gas conveying mechanism is used for providing power for the circulating gas to complete the circulating process.
In some embodiments of the present invention, the circulation gas path further includes a flow rate adjustment mechanism for adjusting a flow rate of the circulation gas.
In some embodiments of the invention, the gas delivery mechanism is a fan;
and/or the flow regulating mechanism is arranged on a fan frequency modulator on the fan or a flow regulating baffle arranged close to the input end of the fan.
In some embodiments of the invention, the radiant chamber is a square box furnace;
the electric heating elements are arranged on one or more surfaces of six walls of the radiation chamber;
and/or the electrical heating element is disposed between an inner wall of the radiant chamber and the radiant coil.
As mentioned above, the electric heating ethylene cracking furnace device of the invention has the following beneficial effects:
1) clean energy such as water and electricity, wind power, photovoltaic power generation and the like can be adopted for power supply, and zero emission of greenhouse gases and harmful gas pollutants is realized.
2) The heat-carrying gas in the furnace is recycled, so that the thermal efficiency of the cracking furnace can be effectively improved to more than 98 percent from about 93 percent at present.
3) Different from other electric heating ethylene cracking furnaces, the device keeps the mature and reliable structural form of a radiation chamber and a convection chamber of the traditional cracking furnace, and enables the cracking reaction and the energy recovery to be carried out simultaneously.
4) The modification amount for realizing electric heating modification of the traditional fuel combustion type cracking furnace is small, and the modification engineering investment is greatly reduced.
5) Different from the traditional flame heating mode, the radiation coil pipe is not fired, the working environment is improved, and the service life of the furnace pipe is prolonged. The gas in the cracking furnace and the gas circulating pipeline can be replaced to achieve the purposes of fire prevention, long service life and enhanced radiation heat transfer.
The cracking furnace device is suitable for raw materials such as ethane, propane, liquefied gas, naphtha, diesel oil, hydrogenated tail oil, condensate oil and crude oil, or a mixture containing the components.
The present invention is equally applicable to other types of tubular heating furnaces such as reformer, EDC cracking furnace, acetic acid cracking furnace, PDH device heating furnace, styrene device steam superheating furnace, PX device heating furnace, atmospheric and vacuum furnace, catalytic reformer heating furnace, coke oven, and the like. The reference to the application of an industrial furnace of the above type also falls within the scope of protection of the present application.
Drawings
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein the accompanying drawings are included to provide a further understanding of the invention and form a part of this specification, and the illustrated embodiments and descriptions thereof are intended to illustrate and not limit the invention.
FIG. 1 is a schematic view of an electrically heated ethylene cracking furnace apparatus according to the present invention;
FIG. 2 is a schematic view of an electrically heated ethylene cracking furnace apparatus according to example 1 of the present invention;
FIG. 3 is a schematic view of a fuel-type cracking furnace apparatus according to example 2 of the present invention modified to an electrically heated ethylene cracking furnace apparatus as described in the present application;
FIG. 4 is a schematic view of an electrically heated ethylene-cracking furnace apparatus according to example 3 of the present invention;
FIG. 5 is a schematic view of an electrically heated ethylene-cracking furnace apparatus according to example 4 of the present invention;
FIG. 6 is a schematic view of a methanol converter apparatus according to the present invention in example 5.
The reference numbers of the figures illustrate the following:
1. a furnace body;
11. a radiation chamber;
111. an electric heating element; 112. a radiant coil; 113. a recycle gas inlet;
12. a convection chamber;
121. a recycle gas outlet; 122. a heat exchange tube bundle;
2. circulating the gas circuit;
3. a flow regulating baffle;
4. a fan;
5. a replacement gas inlet;
6. a displaced gas outlet;
7. and a baffle plate.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
It will be apparent that those skilled in the art can make many modifications and variations based on the spirit of the present invention.
It will be apparent to those skilled in the art that, as used herein, the singular forms "a," "an," "the," and "the" may include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element, component or section is referred to as being "connected" to another element, component or section, it can be directly connected to the other element or section or intervening elements or sections may also be present. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description, "plurality" means two or more unless specifically limited otherwise.
Unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It will be understood by those skilled in the art that, unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.
As shown in figure 1, the technical scheme of the invention is further developed by combining the schematic diagram of an electric heating ethylene cracking furnace device:
in this schematic view 1, the furnace body 1 includes two radiation chambers 11, the two radiation chambers 11 share one convection chamber 12, a radiation coil 112 is suspended in the radiation chamber 11, an electric heating element 111 is installed between the inner wall of the hearth of the radiation chamber 11 and the radiation coil 112, and a plurality of groups of heat exchange tube bundles 122 are arranged in the convection chamber 12.
Set up circulation gas circuit 2 outside the stove body, adopt fan 4 to provide the power of circulation gas circulation, set up flow control baffle 3 on circulation gas circuit 2 and near fan 4 input. The circulating gas inlets 113 are respectively arranged at the bottoms of the two radiation chambers 11, and the circulating gas outlet 121 is arranged at the top of the convection chamber 12. As shown in fig. 1, one replacement gas inlet 5 is provided on each of the lower sides of the bodies of the two radiation chambers, one replacement gas inlet 5 is provided on the circulation gas path, one replacement gas outlet 6 is provided on the upper side of the body of the convection chamber 12, and one replacement gas outlet 6 is provided on the circulation gas path. Wherein, the replacement gas inlet is selectively arranged on the furnace body and/or the circulating gas path, and the replacement gas outlet is selectively arranged on the furnace body and/or the circulating gas path.
The material of the electric heating element is selected according to the working environment and the process requirement, at least one or more of iron-chromium-aluminum alloy, nickel-chromium alloy, silicon carbide or molybdenum disilicide can be selected, and the electric heating element is arranged on one or more surfaces of six walls of the square box type closed hearth according to the process requirement.
Specifically, the circulating gas enters the radiation chamber of the cracking furnace from a circulating gas inlet at the bottom of the radiation chamber (upstream in the circulating gas flowing direction), is heated by an electric heating element, flows through the convection chamber as a heat carrier, and exchanges heat with a heat exchange tube bundle in the convection chamber, and the heat can be used for raw material preheating, boiler water supply preheating, material mixing preheating, dilution steam overheating, high-pressure steam overheating and the like. And the circulating gas flows out from a circulating gas outlet at the top of the convection chamber (downstream in the flowing direction of the circulating gas) after heat exchange, returns to a circulating gas inlet at the bottom of the radiation chamber through a circulating gas path again, and is recycled. The power of the circulating gas is provided by a fan arranged in the circulating gas path, wherein the flow of the circulating gas can be adjusted by arranging a flow adjusting baffle and/or a fan frequency modulator at the input end of the fan.
In addition, the electric heating element is adopted to provide heat required by the cracking reaction, and radiation heat transfer is mainly adopted in the radiation chamber. The electric heating element is arranged in a radiation chamber of the cracking furnace and can be arranged on one or more surfaces of a wall body in the hearth, the electric heating element is arranged between the inner wall of the furnace wall and the radiation coil, and the power of the electric heating element is adjustable. When the working condition of the cracking furnace is changed, the overall or local heat load of the cracking furnace can be changed by adjusting the power of the electric heating element.
Moreover, the gas in the cracking furnace and the gas in the circulating gas circuit can be selectively replaced. The replacement gas enters from the replacement gas inlet, and the replaced gas is discharged from the replacement gas outlet. There are three options for displacement gas: 1) the replacement gas is protective gas such as nitrogen or inert gas, so that the cracking furnace is in non-oxidizing atmosphere; 2) the replacement gas is carbon dioxide and/or water vapor to enhance radiation heat transfer; 3) the displacement gas is a mixture of the above protective gases, carbon dioxide and/or water vapor. And after the gas replacement in the cracking furnace and the circulating gas pipeline is finished, a replacement gas inlet and a replacement gas outlet are closed.
The circulating gas in the cracking furnace and the circulating gas pipeline may or may not be replaced by replacement gas.
An exemplary embodiment of the electrically heated ethylene cracking furnace apparatus of the present application is given below.
Example 1
As shown in fig. 2, an electrically heated ethylene cracking furnace apparatus:
the cracking raw material is naphtha, the feeding amount is 84.5 tons/hour, the ratio of the flow rate of the dilution steam to the flow rate of the raw material is 0.5 (mass ratio), and the capacity of the cracking furnace device is 20.7 ten thousand tons of ethylene per year.
The furnace body 1 of the cracking furnace of the present embodiment has a pair of radiation chambers 11 sharing a single convection chamber 12, the overall dimensions (length × width × height) of the pair of radiation chambers 11 are 30 × 4 × 13.5 m, and the overall dimensions (length × width × height) of the convection chamber 12 are 21 × 3.8 × 29.5 m. Electrothermal elements 111 are arranged on the side wall and the bottom of a hearth of the radiation chamber 11, and the total heat load of the cracking furnace is 133 Gcal/h. U-shaped radiant coils 112 are suspended in the radiant chamber 11, and 192 groups of U-shaped radiant coils are shared by the two radiant chambers. In operation, the electrical heating element 111 of the radiant chamber 11 generates heat and radiatively heats the radiant coil 112, and the feedstock undergoes a cracking reaction within the radiant coil 112.
A circulating gas path 2 is arranged outside a furnace body 1, the circulating gas path 2 is communicated with a cracking furnace through a circulating gas inlet 113 at the bottom of a radiation chamber 11 and a circulating gas outlet 121 at the top of a convection chamber 12, the circulating gas enters the radiation chamber 11 from the circulating gas inlet 113, is heated by an electric heating element 111 and then enters the convection chamber 12 as a heat carrier, sequentially flows through a lower mixing preheating section, a high-pressure steam superheating section, an upper mixing preheating section, a dilution steam superheating section, a raw material secondary preheating section, a boiler water feeding preheating section and a raw material primary preheating section of a heat exchange tube bundle 122, enters the circulating gas path 2 from the circulating gas outlet 121 at the top of the convection chamber 12, passes through a fan 4 and then returns to the radiation chamber from a circulating gas inlet 113 at the bottom of the cracking furnace for heating and recycling.
Wherein, the electric heating element is made of silicon-molybdenum rod.
The circulating gas outlets 121 are provided at the top of the convection chamber (downstream in the circulating gas flow direction), and the number is 1. The circulation gas inlet 113 is provided at the bottom of the radiation chamber 11 (upstream in the circulation gas flow direction), and 1 is provided per radiation chamber.
The fan 4 is used as a circulating gas heat carrierThe power output of the body is arranged on the top surface of the steel structure foundation of the cracking furnace (the top elevation of the steel structure foundation is plus 1.4m, and the bottom elevation of the cracking furnace is plus 4 m). Fan flow 3033Nm3Min and 200kW rated power. A variable frequency fan is selected, a flow regulating baffle 3 is arranged in front of a fan 4, and the flow of circulating gas is regulated through the combination of a frequency converter and the flow regulating baffle.
The circulating gas in the cracking furnace is a mixed gas of nitrogen and carbon dioxide, and is introduced from a replacement gas inlet 5, and the replaced gas in the device is discharged from a replacement gas outlet 6.
The replacement gas inlet 5 is provided at two places: 1 replacement gas inlet 5 is arranged between the flow regulating baffle and the fan on the circulating gas pipeline; and 2 replacement gas inlets 5 are arranged at the lower part of the side wall of each radiation chamber.
The replacement gas outlet 6 is arranged on the circulating gas pipeline, and 1 replacement gas outlet 6 is arranged in front of the flow regulating baffle 3 and close to the flow regulating baffle 3.
Example 2
As shown in fig. 3, a raw fuel combustion type cracking furnace of an ethylene production plant is modified into an electric heating cracking furnace:
the cracking raw material is a mixture of ethane and propane as a raw material, the feeding amount is 8 tons/hour, the ratio of the flow rate of dilution steam to the flow rate of the raw material is 0.3 (mass ratio), and the capacity of a cracking furnace device is 3 ten thousand tons of ethylene per year.
The structure of the original cracking furnace is as follows:
the furnace body 1 has a structure of a single radiation chamber 11 and a single convection chamber 12. The radiation chamber 11 has an outer dimension (length × width × height) of 8 × 2.8 × 10 m, and the convection chamber 12 has an outer dimension (length × width × height) of 8 × 1.6 × 13 m. The radiant chamber 11 suspends the radiant coils 112, and the radiant coils 112 are single-pass small-diameter furnace tubes which go in and out from the lower part and the upper part, and the total number of the radiant coils is 48. The cracking furnace supplies heat to the full-bottom burner, and the total heat load of a single cracking furnace is 14.5 Gcal/h. The heat exchange tube bundle 122 is respectively a lower mixing preheating section, a high-temperature steam superheating section, a low-temperature steam superheating section, an upper mixing preheating section, a boiler water feeding section and a raw material preheating section from bottom to top along the flow direction of flue gas. The flue gas of the cracking furnace is led out to a furnace top chimney by a furnace top induced draft fan 4 and is discharged outside. 326Nm flow of induced draft fan3Min, power rating of 55kW。
The transformation scheme is as follows:
1) the structure of a furnace body 1 of the cracking furnace is unchanged, a burner at the bottom is removed, a burner interface is plugged, electric heating elements are arranged on the side wall and the bottom of a radiation chamber 11, the total heat load of a single cracking furnace is 13.7Gcal/h after transformation, the power of the electric heating elements is adjustable, and the electric heating elements are made of nickel-chromium-aluminum alloy.
2) A bypass flue is newly added at the outlet of the induced draft fan 4 and is led to the bottom of the cracking furnace as a circulating gas path 2, and 2 circulating gas inlets 113 are newly arranged at the bottom of the cracking furnace and are connected with the circulating gas path 2.
3) And a baffle door 7 is additionally arranged at the lower part of the original chimney and the top of the newly-added bypass flue to plug the chimney.
4) The induced draft fan 4 is used for old. Compared with a fuel burner, normal-temperature combustion-supporting air needs to be continuously supplemented in the heating process, high-temperature flue gas is generated after the fuel is burnt, the pyrolysis furnace uses circulating gas as a heat carrier after the pyrolysis furnace is modified, and the temperature of circulating gas at the bottom of the furnace is about 120 ℃. Because no heat loss of exhaust smoke is generated after the transformation, the heat load of the cracking furnace is reduced, and the flow of the circulating heat-carrying gas in the cracking furnace is reduced to 310Nm compared with the flow of the exhaust smoke before the transformation3And/min. The induced draft fan can be used for old.
5) And a flow adjusting baffle 3 is arranged on the circulating gas path 2 close to the inlet of the induced draft fan 4.
6) The lower part of the radiation chamber 11 and the circulating gas outlet 121 are respectively provided with 1 replacement gas inlet 5, and the top of the convection chamber 12 is provided with 2 replacement gas outlets 6.
7) The replacement gas is a mixture of argon, water vapor and carbon dioxide.
When the cracking furnace device is in operation, the electric heating element generates heat to provide heat required by the cracking reaction in the radiation coil. The circulating gas is heated by the electric heating element in the radiation chamber, enters the convection section tube bundle as a heat carrier to be subjected to heat recovery and utilization, and the circulating gas after heat exchange enters the circulating gas path from the top of the convection chamber. The circulating gas is guided to the bottom of the cracking furnace by the induced draft fan, and returns to the radiation chamber after being heated by the furnace bottom electric heating element.
The scheme can successfully realize the conversion from the fuel combustion type cracking furnace to the electric heating cracking furnace under the conditions of small change amount and small investment, does not discharge greenhouse gases and harmful gas pollutants, can improve the heat efficiency from 92 percent to more than 98 percent, and adopts the electric heating to be environment-friendly and accord with the development trend of the cracking furnace. The modified radiant coil is not subjected to fire, and the interior of the furnace is in non-oxidizing atmosphere, so that the service life of the furnace tube is prolonged, and the economic benefit is greatly improved.
Example 3
As shown in fig. 4, an electrically heated ethylene cracking furnace apparatus:
the cracking raw material is naphtha, the feeding amount is 40 tons/hour, and the capacity of the cracking furnace device is 10 ten thousand tons/year.
The furnace body 1 of the cracking furnace of the present embodiment is a single radiation chamber 11 and a single convection chamber 12, and the overall dimensions (length × width × height) of the radiation chamber 11 are 31 × 4 × 112 m, and the overall dimensions (length × width × height) of the convection chamber 12 are 25.8 × 2 × 24.8 m.
The radiation chamber and the convection chamber are arranged in parallel. The top, the bottom and the side walls of the hearth of the radiation chamber 11 are provided with electric heating elements 111, and the total heat load of the cracking furnace is 65 Gcal/h. U-shaped radiant coils 112 are suspended in the radiant chamber 11, and 112 groups of U-shaped radiant coils are arranged in the radiant chamber. In operation, the electrical heating element 111 of the radiant chamber 11 generates heat and radiatively heats the radiant coil 112, and the feedstock undergoes a cracking reaction within the radiant coil 112.
A circulating gas path 2 is arranged outside a furnace body 1, the circulating gas path 2 is communicated with a cracking furnace through a circulating gas inlet 113 at the bottom of a radiation chamber 11 (upstream in the circulating gas flowing direction) and a circulating gas outlet 121 at the bottom of a convection chamber 12 (downstream in the circulating gas flowing direction), circulating gas enters the radiation chamber 11 from the circulating gas inlet 113, is heated by an electric heating element 111 and then enters the convection chamber 12 as a heat carrier, mixed raw material preheating two-stage-SHP steam preheating one-stage-diluted steam preheating one-stage-mixed raw material preheating one-stage-boiler water supply preheating stage-raw material preheating stage sequentially flows through a heat exchange tube bundle 122, enters the circulating gas path 2 from the circulating gas outlet 121 at the bottom of the convection chamber 12, returns to the radiation chamber through a circulating gas inlet 113 at the bottom of the cracking furnace after passing through a fan 4, and is heated and utilized again.
Wherein, the electric heating element is made of silicon-molybdenum rod.
The circulating gas outlets 121 are arranged at the bottom of the convection chamber and are 1 in number. The circulating gas inlets 113 are provided at the bottom of the radiation chamber 11 in a number of 1.
The power output of the fan 4 as a circulating gas heat carrier is flush with the basic height of the cracking furnace. A variable frequency fan is selected, a flow regulating baffle 3 is arranged in front of a fan 4, and the flow of circulating gas is regulated through the combination of a frequency converter and the flow regulating baffle.
The circulating gas is air, and the gas in the furnace is not replaced.
Example 4
As shown in fig. 5, this embodiment is a modification of the apparatus described in embodiment 3:
the process conditions, the physical dimensions of the radiation chamber and the convection chamber, the structure and the number of the radiation coils, and the material of the electric heating elements of the cracking device are the same as those of the embodiment 3.
In this embodiment, the recycle gas inlet 113 is disposed at the top of the radiation chamber 11 (upstream in the flow direction of the recycle gas), the recycle gas outlet 121 is disposed at the top of the convection chamber 12 (downstream in the flow direction of the recycle gas), and the fan 4 is disposed on the top platform of the cracking furnace. The circulating gas enters from the circulating gas inlet 113 at the top of the radiation chamber 11, enters the convection chamber 12 from bottom to top in the flowing direction of the radiation chamber 11 to sequentially pass through the heat exchange tube bundles 122 for convection heat transfer, is discharged from the circulating gas outlet 121 at the top of the convection chamber 12 to enter the circulating gas path 2 for external circulation, finally returns to the radiation chamber 11 to perform heating circulation again.
The circulating gas is air, and the gas in the furnace is not replaced.
Example 5
As shown in fig. 6, is a schematic diagram of a methanol plant reformer designed according to the scheme of the present application:
the cracking raw material is a mixture of natural gas and steam, and the feeding amount is 13800Nm3/h。
The furnace body of the reformer is of a structure with a single radiation chamber 11 and a single convection chamber 12. The radiation chamber 11 has an outer dimension (length × width × height) of 9.7 × 6.3 × 19 m, and the convection chamber 12 has an outer dimension (length × width × height) of 15.8 × 5.3 × 4 m. The radiant chamber 11 suspends the radiant coils 112, and the radiant coils 112 are single-pass small-diameter furnace tubes which go in and out from the lower part and the upper part, and the number of the radiant coils is totally 42. The electric heating elements are arranged on the top and the side walls of the radiation chamber, and the total heat load of a single cracking furnace is 16 Gcal/h. The convection chamber 12 is horizontally arranged, and a first water supply preheating pipe bundle, a mixed gas preheating pipe bundle, a natural gas preheating pipe bundle, a steam preheating pipe bundle, a second water supply preheating pipe bundle and a fuel gas preheating pipe bundle are sequentially arranged along the flowing direction of the circulating gas.
A circulating gas inlet 113 is provided at the top (upstream in the circulating gas flow direction) of the radiation chamber 11, and a circulating gas outlet 121 is provided at the end (downstream in the circulating gas flow direction) of the convection chamber 12 and connected to the circulating gas passage 113. A fan 4 is arranged on the circulating gas path 2 and used as the power output of circulating gas, and a flow adjusting baffle 3 is arranged in front of the fan 4. The inlet and the outlet of the fan 4 are respectively provided with a replacement gas outlet 6 and a replacement gas inlet 5. The replacement gas is a mixed gas of nitrogen and carbon dioxide.
Wherein, the electric heating element is made of silicon carbide rod.
Before the operation, the flow regulating baffle 3 is closed, and the fan 4 is started. The replacement gas enters from a replacement gas inlet 5, and the replaced gas in the furnace and in the circulating gas path 2 is discharged from a replacement gas outlet 6. When the closed loop is filled with the replacement gas, the fan 4 is closed to stop gas replacement, and the replacement gas inlet and outlet are sealed by a blind flange.
When the device is operated, the electric heating element generates heat, and the radiation coil is heated in a heat radiation mode to carry out in-tube cracking reaction. Circulating gas enters from a circulating gas inlet at the top of the radiation chamber, is heated by an electric heating element and then enters the convection section as a heat carrier, heat is recycled through each section of tube bundle in the convection section in sequence, and the circulating gas after heat exchange flows out from a circulating gas outlet at the end part of the convection section and enters a circulating gas circuit. The fan leads the circulating gas to the circulating gas inlet at the top of the radiation chamber and returns to the radiation chamber again for heating.
The cracking furnace device is suitable for raw materials such as ethane, propane, liquefied gas, naphtha, diesel oil, hydrogenated tail oil, condensate oil and crude oil, or a mixture containing the components. And the present application is also applicable to other types of tubular heating furnaces such as a reformer, an EDC cracking furnace, an acetic acid cracking furnace, a PDH device heating furnace, a styrene device steam superheating furnace, a PX device heating furnace, an atmospheric and vacuum furnace, a catalytic reformer heating furnace, a coke furnace, and the like.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (10)

1. An electrically heated ethylene cracking furnace apparatus, comprising: a cracking furnace and a circulating gas circuit;
the cracking furnace at least comprises a furnace body, a radiation coil, an electric heating element and a heat exchange tube bundle, wherein the radiation coil, the electric heating element and the heat exchange tube bundle are arranged in the furnace body;
the furnace body is provided with a circulating gas inlet and a circulating gas outlet, and two ends of the circulating gas path are respectively communicated with the circulating gas inlet and the circulating gas outlet;
the circulating gas circuit and the furnace body form a closed loop which is used as a channel for circulating gas to flow;
the electric heating element is used for transferring heat required by cracking reaction to the process fluid in the radiant coil pipe and providing heat of circulating gas in the furnace body;
the heat exchange tube bundle is used for recovering heat of the circulating gas.
2. The electrically heated ethylene cracking furnace apparatus of claim 1, wherein the furnace body further comprises a radiant chamber and a convection chamber in communication with each other;
the radiant coil is arranged in the radiant chamber, and the heat exchange tube bundle is arranged in the convection chamber;
the circulating gas inlet is arranged in the radiation chamber, and the circulating gas outlet is arranged in the convection chamber;
the circulation gas is used to transfer the heat obtained in the radiant chamber to the heat exchanger bundle.
3. The apparatus of claim 2, wherein the recycle gas inlet is disposed in the radiant chamber and upstream of the flow direction of the recycle gas in the cracking furnace;
and/or the circulating gas outlet is arranged in the convection chamber and is positioned at the downstream of the circulating gas flowing direction in the cracking furnace.
4. The electrically heated ethylene cracking furnace apparatus of claim 3, wherein one or more of the radiation chambers are provided;
and/or one or more circulating gas inlets are arranged;
and/or one or more circulating gas outlets are arranged.
5. The electrically heated ethylene cracking furnace apparatus of claim 1, wherein the furnace body and/or the circulating gas circuit is provided with a replacement gas inlet and a replacement gas outlet;
the replacement gas inlet is used for introducing replacement gas, and the replacement gas outlet is used for discharging replaced gas in the furnace body;
preferably, the displacement gas is selected from one or more of nitrogen, an inert gas, carbon dioxide or water vapour.
6. The electrically heated ethylene cracking furnace apparatus of claim 5, wherein one or more of the replacement gas inlets are provided;
and/or one or more displacement gas outlets are arranged.
7. The electrically heated ethylene cracking furnace apparatus of claim 1, wherein the circulating gas circuit further comprises a gas delivery mechanism;
the gas conveying mechanism is used for providing power for the circulating gas to complete the circulating process.
8. The electrically heated ethylene cracking furnace apparatus of claim 7, wherein the circulating gas path further comprises a flow rate adjusting mechanism for adjusting the flow rate of the circulating gas.
9. The electrically heated ethylene cracking furnace apparatus of claim 8, wherein the gas delivery mechanism is a fan;
and/or the flow regulating mechanism is arranged on a fan frequency converter on the fan and/or a flow regulating baffle plate close to the input end of the fan.
10. An electrically heated ethylene cracking furnace apparatus as claimed in any one of claims 2 to 4, wherein the electric heating element is disposed on one or more sides of the plurality of walls of the radiant chamber;
and/or the electrical heating element is disposed between an inner wall of the radiant chamber and the radiant coil.
CN202111100813.4A 2021-09-18 2021-09-18 Electric heating ethylene cracking furnace device Pending CN113801683A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111100813.4A CN113801683A (en) 2021-09-18 2021-09-18 Electric heating ethylene cracking furnace device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111100813.4A CN113801683A (en) 2021-09-18 2021-09-18 Electric heating ethylene cracking furnace device

Publications (1)

Publication Number Publication Date
CN113801683A true CN113801683A (en) 2021-12-17

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111100813.4A Pending CN113801683A (en) 2021-09-18 2021-09-18 Electric heating ethylene cracking furnace device

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023126294A1 (en) * 2021-12-30 2023-07-06 Totalenergies Onetech Belgium Apparatus and process for hydrocarbon steam cracking

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023126294A1 (en) * 2021-12-30 2023-07-06 Totalenergies Onetech Belgium Apparatus and process for hydrocarbon steam cracking

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