CN117186927A - Reactor and method for preparing low-carbon olefin by directly heating hydrocarbon through heat carrier - Google Patents
Reactor and method for preparing low-carbon olefin by directly heating hydrocarbon through heat carrier Download PDFInfo
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- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention relates to a reactor and a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier. The method is implemented based on the reactor and comprises the following steps: s1: respectively and simultaneously introducing hydrogen and a mixture of water vapor and oxygen into an oxyhydrogen burner, wherein the high-temperature water vapor generated by hydrogen combustion enters a combustion zone cylinder; s2: the high-temperature steam sequentially flows through the shrinkage cone and the constant-diameter nipple, is mixed with raw materials from the first raw material inlet and the second raw material inlet, partial raw materials are cracked, then the raw materials enter the expansion cone and are mixed and reacted with raw materials from the third raw material inlet, and the reaction product enters a quenching zone to be cooled, so that the target product is obtained. Compared with the prior art, the reactor and the method have the characteristics of wide application range of raw materials, high selectivity of target products and the like.
Description
Technical Field
The invention belongs to the technical field of olefin production equipment, and relates to a reactor and a method for preparing low-carbon olefin by directly heating hydrocarbon and cracking by using a heat carrier.
Background
Ethylene cracking furnaces are important equipment units in the petrochemical industry, and more than 90% of ethylene worldwide is produced by the ethylene cracking furnaces. The existing ethylene cracking furnace consists of a radiation chamber, a convection chamber, a quenching boiler, a burner and the like, wherein the burner is arranged in the radiation chamber, and fuel is combusted through the burner to generate a large amount of high-temperature flue gas. The radiation furnace tube is hung in the radiation chamber, and the high-temperature flue gas transfers heat to the radiation furnace tube in the radiation chamber through radiation heat transfer, so that the medium in the tube is heated, the raw materials are subjected to cracking reaction, and low-carbon olefin is generated. In the process, the heat of the high-temperature flue gas is transferred to the inside of the pipe from the outside of the pipe, and the medium is heated, and the high-temperature flue gas is not in direct contact with the materials in the pipe, which is called indirect heat exchange. The heat transfer intensity of the process is limited by the highest use temperature of the material of the radiation furnace tube, the radiation furnace tube can force the cracking furnace to stop frequently due to coking, the service life of the radiation furnace tube is only 5-6 years in long-term use, the heating rate of the cracking furnace is only 92-94% in general, and the raw materials need to be preheated and vaporized in the convection section heat exchange tube, and what raw materials are used as cracking raw materials are limited to a certain extent.
In order to eliminate the defects of the traditional cracking furnace, the source range of cracking raw materials is widened, a great deal of research is carried out on the research of directly heating hydrocarbon to prepare olefin by using a heat carrier by technicians in the last 70 th century, and a certain exploratory research is carried out on a method for preparing olefin by directly cracking crude oil by the technicians in recent years.
The direct heating of hydrocarbon cracking by the heat carrier means that the heat carrier is directly mixed with the cracking raw material, the heat carrier directly transfers heat to the cracking raw material in a way of directly contacting with the cracking raw material, and the cracking raw material is subjected to cracking reaction after reaching the temperature at which the cracking reaction occurs.
CN 101875591a discloses a process for preparing low-carbon olefin by hydrocarbon cracking. The method is that preheated hydrocarbon raw material and hydrogen gas and oxygen-containing gas are introduced into a plurality of units comprising a hydrogen catalytic combustion device and an adiabatic reaction device; in the hydrogen catalytic combustion device, energy is provided for hydrogen combustion to raise the temperature of the mixed material to the temperature required for cracking reaction; in an adiabatic reactor, a thermal cracking reaction occurs to produce a stream containing light olefins; finally, after heat is recovered by a quenching device, various low-carbon olefin products are obtained by a separation system. The technology adopts a selective hydrogen combustion catalyst, and introduces hydrogen, oxygen and a cracking raw material mixture into a hydrogen catalyst device, so that the hydrogen in the hydrogen is subjected to catalytic combustion reaction, and heat is provided for the cracking reaction.
US3161695 discloses a process for preparing alkyne, wherein the reactor is a circular tube, the tube wall of the circular tube has a certain heat conduction property, the outside of the circular tube is annular high temperature resistant material, a certain gap is formed between the annular high temperature resistant material and the outer wall of the circular tube reactor, the gap is a combustion chamber, hydrogen and oxygen are combusted in the combustion chamber, the hydrogen and the oxygen go up along the space of the combustion chamber and then are mixed with raw materials entering from the top end of the circular tube reactor, the raw materials enter a circular reaction tube, a cracking reaction occurs in the tube, the tube wall of the circular reactor has a certain heat conduction property, and a certain amount of heat can be supplemented for the cracking reaction.
The direct cracking technology of crude oil disclosed in WO 2004/005431 A1, US7578929B2 and the like is characterized in that crude oil is used as a cracking raw material, but certain requirements are imposed on the properties of the crude oil, meanwhile, heavy end components in the crude oil need to be cut out in the processing process, and only parts of the crude oil which are suitable as the cracking raw material are sent into a traditional tubular steam cracking furnace for cracking, so that the source of the cracking raw material is enlarged to a certain extent.
In summary, the prior art generally has the problems of narrow raw material application range, long reaction residence time, short operation period, low thermal efficiency, large greenhouse gas emission, catalyst requirement and the like.
Disclosure of Invention
The invention aims to provide a reactor and a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier, so as to overcome the defects of narrow raw material application range, long reaction residence time, short operation period, low heat efficiency, large emission of greenhouse gases, catalyst requirement and the like in the technology for preparing low-carbon olefin by hydrocarbon pyrolysis in the prior art. In view of the defects of the prior cracking technology, the invention provides a reactor and a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier. The reactor and the method have the advantages of wide raw material application range, high thermal efficiency and no emission of greenhouse gases, can meet the conditions of high temperature, short residence time, low hydrocarbon partial pressure and the like required by the cracking reaction, can obviously improve the selectivity of target olefin, and prolong the operation period of the reactor.
The aim of the invention can be achieved by the following technical scheme:
One of the technical schemes of the invention provides a reactor for preparing light olefins by directly heating hydrocarbon and cracking by a heat carrier, which comprises the following components:
combustion zone for providing high temperature water vapor: the combustion zone cylinder body with one closed end is provided with an oxyhydrogen burner;
a mixing pre-reaction zone downstream of the combustion zone for mixing the feedstock and the high temperature steam: the combustion zone cylinder comprises a shrinkage cone and an equal-diameter short joint, wherein the flaring end of the shrinkage cone is connected with the unsealed end of the combustion zone cylinder, the necking end of the shrinkage cone is connected with one end of the equal-diameter short joint, the shrinkage cone is provided with a first raw material inlet, and the equal-diameter short joint is provided with a second raw material inlet;
a main reaction zone downstream of the mixed pre-reaction zone: the device comprises an expansion cone, wherein the closing end of the expansion cone is connected with the other end of the equal-diameter short joint, and the expansion cone is provided with a third raw material inlet;
a quench zone downstream of the primary reaction zone for stopping the cracking reaction.
Further, the oxyhydrogen burner is provided with a plurality of oxyhydrogen burners, and the oxyhydrogen burner is arranged on the side wall of the combustion zone cylinder body or on the central part of the closed end of the combustion zone cylinder body at equal intervals around the central axis of the combustion zone cylinder body.
Further, when the oxyhydrogen burner is arranged on the side wall of the combustion zone cylinder, an included angle formed by the center line of flame sprayed by the oxyhydrogen burner and the circumferential tangent line of the side wall of the combustion zone cylinder is 0-180 degrees.
Further, when the oxyhydrogen burner is disposed at the central portion of the closed end of the combustion zone cylinder, the center line of flame emitted from the oxyhydrogen burner is parallel to the center line of the combustion zone cylinder.
Further, when a plurality of oxyhydrogen burners are arranged on the side wall of the combustion zone cylinder, the plurality of oxyhydrogen burners are arranged in a plurality of layers.
Further, the inner wall of the combustion zone cylinder body is also provided with a high-temperature-resistant heat-insulating material layer.
Further, the high-temperature-resistant heat-insulating material layer is one or a combination of a plurality of high-temperature-resistant fiber layers, high-temperature-resistant brick layers or high-temperature-resistant castable layers.
Further, the combustion zone cylinder body is of a double-layer jacket structure, and a cooling medium is filled in the jacket.
Still further, the cooling medium is water, liquid hydrocarbons, methanol or silicone oil.
Further, the first raw material inlets are arranged in a plurality, and the first raw material inlets are arranged on the side wall of the shrinkage cone at equal intervals around the central axis of the shrinkage cone.
Furthermore, the first raw material inlets are arranged in a plurality of layers, and each layer is provided with 2-4 first raw material inlets.
Still further, the first feedstock inlet is disposed vertically on a sidewall of the converging cone.
Further, the second raw material inlets are arranged in a plurality, and the second raw material inlets are arranged on the side wall of the equal-diameter nipple at equal intervals around the central axis of the equal-diameter nipple.
Furthermore, the plurality of second raw material inlets are arranged in a plurality of layers, and each layer is provided with 2-4 second raw material inlets.
Further, the included angle between the central axis of the second raw material inlet and the side wall of the constant diameter nipple is 10-170 degrees.
Further, the third raw material inlets are arranged in a plurality, and the third raw material inlets are arranged on the side wall of the expansion cone at equal intervals around the central axis of the expansion cone.
Furthermore, the plurality of third raw material inlets are arranged in a plurality of layers, and each layer is provided with 2-4 third raw material inlets.
Further, the included angle between the central axis of the third raw material inlet and the side wall of the expansion cone is 10-170 degrees.
Further, the included angle between the side wall of the constant diameter nipple and the side wall of the expansion cone is 100-170 degrees, and can be 115-135 degrees.
Further, the included angle between the side wall of the shrinkage cone and the side wall of the combustion zone cylinder is 100-170 degrees, and is optionally 120-150 degrees.
Further, the quenching zone comprises a heat exchange cylinder, and one end of the heat exchange cylinder is connected with the flaring end of the expansion cone.
Further, the heat exchange cylinder is provided with a direct cooling medium inlet.
Further, the heat exchange cylinder is provided with an indirect heat exchanger.
Further, a secondary cooling zone for further cooling the cracked product is also provided downstream of the quench zone.
Further, the secondary cooling zone is provided with a quench cooler through which a cooling medium is injected and cools the cracked product.
The term "short" in the constant diameter nipple is merely descriptive and does not refer to a specific length.
The second technical scheme of the invention provides a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier, which is implemented by adopting the reactor and comprises the following steps:
s1: the oxyhydrogen burner is started, hydrogen and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner, the hydrogen is combusted, and generated high-temperature steam enters the combustion zone cylinder;
s2: the obtained high-temperature steam sequentially flows through the shrinkage cone and the constant-diameter nipple, is sequentially mixed with cracking raw materials from the first raw material inlet and the second raw material inlet, partial cracking raw materials undergo a cracking reaction, then the materials enter the expansion cone and are mixed with the cracking raw materials from the third raw material inlet and further react, and the reaction product enters the quenching zone to be cooled, so that the target product is obtained.
Further, in step S1, while oxygen is being introduced, water vapor is also introduced, and the mixing volume ratio of oxygen to water vapor is 1: (0 to 10), and is not 1:0. in the oxyhydrogen burner, hydrogen is introduced into a central passage of the oxyhydrogen burner, and a mixture of oxygen and water vapor is introduced into a sleeve outside the central passage.
Further, in step S1, the temperature of the high-temperature steam at the outlet of the combustion zone cylinder is 1000-1500 ℃, and optionally 1200-1400 ℃. The invention adjusts the temperature of the high-temperature steam at the outlet of the combustion zone cylinder body to be 1000-1500 ℃ by adjusting the ratio of the introduced oxygen to the steam.
Further, in step S2, the cracking feedstock is one or more of ethane, propane, n-butane, liquefied Petroleum Gas (LPG), carbon five, naphtha, diesel, hydrogenated tail oil, condensate, residual oil or crude oil.
Further, in step S2, the first raw material inlet, the second raw material inlet and the third raw material inlet are simultaneously introduced with the pyrolysis raw material, and atomized water vapor (or referred to as protection water vapor) is also introduced, and the mass ratio of the atomized water vapor to the pyrolysis raw material is (0.1-5): 1. atomizing steam normally refers to steam which atomizes the cracking raw material, but when the cracking raw material is just started, the combustion zone cylinder body already has high-temperature steam generated by oxyhydrogen combustion, and when the cracking raw material does not enter, the steam is introduced first to protect nozzles at the position, so that the steam is also called as protection steam.
Further, in step S2, the residence time of the material in the expansion cone is 0.01 to 0.5S, optionally 0.05 to 0.15S, and the temperature of the reaction product at the outlet of the main reaction zone is 600 to 900 ℃. The purpose of adopting the expansion cone is to ensure that the mixture is at a higher flow rate at the position and has smaller friction resistance drop, and the stay time of the materials in the expansion cone is determined by two factors of the inner volume of the expansion cone and the flow rate of the materials at the position.
Further, in the step S2, the flow rate of the material at the equal-diameter short section is 50-200m/S, and optionally 80-120 m/S. In the original design, the volume of the constant diameter nipple is calculated according to the properties of raw materials, the flow rate of the raw materials, the flow rate of water vapor, the temperature and pressure of the raw materials, and the like, so as to ensure that the flow rate is in the range of 50-200 m/s.
Further, in step S2, after the reaction product enters the quenching zone, the reaction product is cooled by directly spraying a cooling medium or by indirect heat exchange.
Further, in step S2, the temperature of the reaction product is 300-600 ℃ after the reaction product is cooled by the quenching zone.
In step S2, the reaction product is cooled by the quenching zone and then enters a secondary cooling zone, and the cooling medium sprayed by the secondary cooling zone further cools the reaction product to 180-250 ℃.
In the step S2, a shrinkage cone of the mixing pre-reaction zone is injected with a cracking raw material, so that the cracking raw material is mixed with high-temperature steam, heat is directly transferred to the cracking raw material by the high-temperature steam, and hydrocarbon which partially reaches the cracking reaction temperature in the cracking raw material undergoes a cracking reaction to form a mixture composed of steam, the cracking raw material and reaction products, the temperature of the mixture is 1000-1100 ℃, then the mixture enters an equal-diameter nipple of the mixing pre-reaction zone, and the cracking raw material is further injected into a second raw material inlet of the equal-diameter nipple, so that the mixing, heat transfer and partial cracking reaction of the materials are further enhanced.
In the step S2, after the materials enter the main reaction zone, the cracking raw materials are continuously injected into a third raw material inlet of the expansion cone, and as the progress of the cracking reaction, small molecular products are increased, the mole number of the mixture is rapidly increased, the equilibrium temperature of the mixture after passing through the expansion cone is 600-900 ℃, the temperature is optionally 750-850 ℃, and the pressure is 0.05-2.5 Mpa G.
In step S2, the reaction product enters a quenching zone for cooling, and different cooling methods can be selected according to the cracking raw materials. When the cracking raw material is lighter, the waste heat of the reaction mixture can be recovered by adopting an indirect heat exchange mode; when the raw materials are heavier, the reaction mixture can be cooled by directly spraying a cooling medium, and then the waste heat is recovered. The temperature of the reaction mixture after heat recovery through the quench zone is between 300 and 600 c, alternatively 350 to 450 c. In the art, the weight of a raw material is generally determined by taking the specific gravity of the raw material as a reference, and generally: ethane, propane, LPG and naphtha are light materials, diesel oil, hydrogenated tail oil and crude oil are heavy materials, the invention takes the specific gravity of the materials as a boundary line, and the specific gravity of the materials below 0.8 can be called light materials and the specific gravity of the materials above 0.8 can be called heavy materials.
In the step S2, the reaction mixture after heat recovery in the quenching zone enters a secondary cooling zone, key equipment in the secondary cooling zone is a quenching device, cooling medium is sprayed through the quenching device, the cooling medium can be water or hydrocarbon, after the cooling medium is sprayed, the reaction mixture is cooled to 180-250 ℃, and the cooled reaction mixture enters a subsequent separation system for further low-temperature heat recovery and component separation.
When the material leaves the expansion cone of the main reaction zone, the temperature of the material still reaches about 800 ℃, and a large amount of secondary reaction occurs under the condition that the material is in the state for a long time, wherein the secondary reaction means that unstable molecules such as olefin, diene and the like further undergo dehydrogenation, polycondensation and the like, so that target olefin is reduced, therefore, the aim of arranging a quenching zone at the outlet of the main reaction zone is to cool reaction products rapidly, and the secondary reaction can be terminated by generally considering that the cooling temperature is below 600-650 ℃.
Compared with the prior art, the invention has the following advantages:
(1) The high-temperature steam generated by oxyhydrogen combustion is directly mixed with the cracking raw material, so that the raw material reaches the temperature required by the cracking reaction in a very short time, the reaction residence time is shortened by more than 50% compared with the prior art, and the high-temperature steam generated by oxyhydrogen combustion also plays a role in reducing the partial pressure of hydrocarbon, so that the selectivity of target products is improved;
(2) The invention adopts a direct heating mode to prepare the low-carbon olefin, has high thermal efficiency, can not generate coking in the heat exchange tube, has wider adaptability of raw materials and longer operation period of the reactor;
(3) The invention adopts high-temperature water vapor generated by oxyhydrogen combustion as a direct heating carrier, and has no emission of greenhouse gases and other pollutants;
(4) The method can prepare the low-carbon olefin without adopting a catalyst.
Drawings
FIG. 1 is a schematic diagram of the structure of the reactor of examples 1-3 (direct cooling);
FIG. 2 is a schematic diagram of the structure of the reactor of example 4 (indirect heat exchange);
FIG. 3 is a flow chart of the process for preparing light olefins by cracking hydrocarbons by direct heating of the heat carrier in examples 2-3;
FIG. 4 is a flow chart of the process for preparing light olefins by cracking hydrocarbons by direct heating of the heat carrier in example 4;
FIG. 5 is a schematic diagram of the parallel use of 5 reactors in example 5;
FIG. 6 is a schematic diagram of the flow of hydrogen, and a mixture of water vapor and oxygen in an oxyhydrogen burner.
The figure indicates:
1-combustion zone, 1-1-oxyhydrogen burner, 1-2-refractory brick layer, 1-3-combustion zone cylinder, 2-mixing pre-reaction zone, 2-1-shrink cone, 2-2-constant diameter nipple, 2-3 first raw material inlet, 2-4 second raw material inlet, 3-main reaction zone, 3-1-expansion cone, 3-2-third raw material inlet, 3-3-main reaction zone outlet, 4-quench zone, 4-1-quench zone inlet, 4-2-quench zone outlet, 4-3-direct cooling medium inlet, 4-4-indirect cooling medium inlet, 4-5-indirect cooling medium outlet, 4-6-indirect heat exchanger, 4-7-heat exchange cylinder, 5-secondary cooling zone.
Detailed Description
The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.
In the following embodiments or examples, unless otherwise specified, functional components or structures are indicated as conventional components or structures employed in the art to achieve the corresponding functions.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In the description of the present invention, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless otherwise indicated.
The invention provides a reactor and a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier, which are used for overcoming the defects of narrow raw material application range, long reaction residence time, short operation period, low thermal efficiency, large emission of greenhouse gases, catalyst requirement and the like in the technology for preparing the low-carbon olefin by hydrocarbon pyrolysis in the prior art.
One of the technical schemes of the invention provides a reactor for preparing light olefins by directly heating hydrocarbon and cracking by using a heat carrier, as shown in figures 1-2, the reactor comprises:
combustion zone 1 for providing high temperature water vapor: the combustion zone cylinder body 1-3 with one end closed is arranged, and the combustion zone cylinder body 1-3 is provided with an oxyhydrogen burner 1-1;
a mixing pre-reaction zone 2 for mixing the feedstock and the high-temperature steam located downstream of the combustion zone 1: the combustion zone cylinder comprises a shrinkage cone 2-1 and an equal-diameter short joint 2-2, wherein the flaring end of the shrinkage cone 2-1 is connected with the unsealed end of the combustion zone cylinder 1-3, the necking end of the shrinkage cone 2-1 is connected with one end of the equal-diameter short joint 2-2, the shrinkage cone 2-1 is provided with a first raw material inlet 2-3, and the equal-diameter short joint 2-2 is provided with a second raw material inlet 2-4;
a main reaction zone 3 downstream of said mixed pre-reaction zone 2: the device comprises an expansion cone 3-1, wherein the closing end of the expansion cone 3-1 is connected with the other end of the constant diameter nipple 2-2, and the expansion cone 3-1 is provided with a third raw material inlet 3-2;
A quench zone 4 downstream of the main reaction zone 3 for stopping the cracking reaction.
In some specific embodiments, the oxyhydrogen burner 1-1 is provided in a plurality, and the oxyhydrogen burners 1-1 are equally spaced around the central axis of the combustion zone cylinder 1-3 on the side wall of the combustion zone cylinder 1-3 or on the central part of the closed end of the combustion zone cylinder 1-3.
In a more specific embodiment, referring to fig. 1-2, a plurality of oxyhydrogen burners 1-1 are equally spaced around the central axis of the combustion zone cylinder 1-3 on the side wall of the combustion zone cylinder 1-3, and the oxyhydrogen burner 1-1 is also disposed at the central part of the closed end of the combustion zone cylinder 1-3.
In a more specific embodiment, when the oxyhydrogen burner 1-1 arranged on the side wall of the combustion zone cylinder 1-3 is in operation, an included angle formed by the central line of flame sprayed by the oxyhydrogen burner and the circumferential tangent line of the side wall of the combustion zone cylinder 1-3 is 0-180 degrees; the oxyhydrogen burner 1-1 arranged at the central part of the closed end of the combustion zone cylinder 1-3 has a center line of flame sprayed out parallel to the center axis of the combustion zone cylinder 1-3 when in operation.
In a more specific embodiment, when a plurality of oxyhydrogen burners 1-1 are disposed on the side wall of the combustion zone cylinder 1-3, the plurality of oxyhydrogen burners 1-1 are disposed in a plurality of layers.
In some embodiments, the inner wall of the combustion zone cylinder 1-3 is provided with a layer of high temperature resistant insulating material.
In a more specific embodiment, the high-temperature-resistant heat-insulating material layer is one or a combination of a plurality of high-temperature-resistant fiber layers, high-temperature-resistant brick layers 1-2 or high-temperature-resistant castable layers.
In a more specific embodiment, referring to fig. 1, a refractory brick layer 1-2 is disposed on the inner wall of the combustion zone cylinder 1-3.
In some specific embodiments, the combustion zone cylinder 1-3 has a double-layer jacket structure, and a cooling medium is filled in the jacket.
In more specific embodiments, the cooling medium is water, a liquid hydrocarbon, methanol, or silicone oil.
In some specific embodiments, referring to fig. 1, the first raw material inlets 2-3 are provided in a plurality, and the plurality of first raw material inlets 2-3 are disposed at equal intervals on the side wall of the shrinkage cone 2-1 around the central axis of the shrinkage cone 2-1.
In a more specific embodiment, the plurality of first raw material inlets 2-3 are arranged in a plurality of layers, and each layer is provided with 2-4 first raw material inlets 2-3.
In a more specific embodiment, the first raw material inlet 2-3 is arranged vertically at the side wall of the shrinkage cone 2-1.
In some specific embodiments, referring to fig. 1, the second raw material inlets 2-4 are provided in a plurality, and the plurality of second raw material inlets 2-4 are disposed on the side wall of the equal-diameter nipple 2-2 at equal intervals around the central axis of the equal-diameter nipple 2-2.
In a more specific embodiment, the plurality of second raw material inlets 2-4 are arranged in a plurality of layers, and each layer is provided with 2-4 second raw material inlets 2-4.
In a more specific embodiment, the included angle between the central axis of the second raw material inlet 2-4 and the side wall of the equal-diameter short section 2-2 is 10-170 degrees.
In some specific embodiments, referring to fig. 1, the third material inlets 3-2 are provided in a plurality, and the plurality of third material inlets 3-2 are disposed on the side wall of the expansion cone 3-1 at equal intervals around the central axis of the expansion cone 3-1.
In a more specific embodiment, the plurality of third raw material inlets 3-2 are arranged in a plurality of layers, and each layer is provided with 2-4 third raw material inlets 3-2.
In a more specific embodiment, the included angle between the central axis of the third raw material inlet 3-2 and the side wall of the expansion cone 3-1 is 10-170 °.
In some embodiments, the angle between the side wall of the equal diameter nipple 2-2 and the side wall of the expansion cone 3-1 is 100-170 degrees, alternatively 115-135 degrees.
In some embodiments, the angle between the side wall of the contracting cone 2-1 and the side wall of the combustion zone cylinder 1-3 is 100-170 °, optionally 120-150 °.
In some embodiments, referring to FIG. 1 or FIG. 2, the quench zone 4 includes a heat exchange cartridge 4-7, with one end of the heat exchange cartridge 4-7 being connected to the flared end of the expansion cone 3-1.
In a more specific embodiment, referring to fig. 1, the heat exchange cylinder 4-7 is provided with a direct cooling medium inlet 4-3.
In a more specific embodiment, referring to fig. 2, the heat exchange cylinder 4-7 is provided with an indirect heat exchanger 4-6.
In some embodiments, referring to fig. 1, a secondary cooling zone 5 is further provided downstream of the quenching zone 4 for further cooling of the cracked product.
In a more specific embodiment, the secondary cooling zone 5 is provided with a quench cooler through which a cooling medium is injected and cools the cracked product.
The second technical scheme of the invention provides a method for preparing low-carbon olefin by directly heating hydrocarbon by using a heat carrier, which is implemented by adopting the reactor and comprises the following steps:
s1: the oxyhydrogen burner 1-1 is started, hydrogen and a mixture of water vapor and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner 1-1, the hydrogen is combusted, and the generated high-temperature water vapor enters the combustion zone cylinder 1-3;
S2: the obtained high-temperature steam sequentially flows through the shrinkage cone 2-1 and the constant diameter nipple 2-2, is sequentially mixed with cracking raw materials from the first raw material inlet 2-3 and the second raw material inlet 2-4, partial cracking raw materials undergo a cracking reaction, then the materials enter the expansion cone 3-1, are mixed with the cracking raw materials from the third raw material inlet 3-2 and further react, and the reaction product enters the quenching zone 4 to be cooled, so that the target product is obtained.
In some specific embodiments, in step S1, in the oxyhydrogen burner 1-1, hydrogen is introduced into a central channel of the oxyhydrogen burner 1-1, and a mixture of oxygen and water vapor is introduced into a jacket outside the central channel.
In some specific embodiments, in step S1, while oxygen is being introduced, water vapor is also introduced, and the mixing volume ratio of oxygen to water vapor is 1: (0 to 10), and is not 1:0.
in some specific embodiments, in step S1, the temperature of the high-temperature steam at the outlet of the combustion zone cylinder 1-3 is 1000-1500deg.C, optionally 1200-1400 ℃. The invention adjusts the temperature of the high-temperature steam at the outlet of the combustion zone cylinder 1-3 to be 1000-1500 ℃ by adjusting the ratio of the introduced oxygen to the steam.
In some specific embodiments, in step S2, the cracking feedstock is one or more of ethane, propane, n-butane, liquefied Petroleum Gas (LPG), carbon five, naphtha, diesel, hydrogenated tail oil, condensate, residuum, or crude oil.
In some specific embodiments, in step S2, the first raw material inlet 2-3, the second raw material inlet 2-4 and the third raw material inlet 3-2 are simultaneously introduced with the pyrolysis raw material, and atomized water vapor (or referred to as protective water vapor) is also introduced, and the mass ratio of the atomized water vapor to the pyrolysis raw material is (0.1-5): 1.
in some embodiments, in step S2, the residence time of the material in the expansion cone 3-1 is from 0.01 to 0.5S, optionally from 0.05 to 0.15S, and the temperature of the reaction product at the outlet 3-3 of the main reaction zone is from 600 to 900 ℃.
In some specific embodiments, in step S2, the material flow rate at the equal-diameter short section 2-2 is 50-200 m/S, optionally 80-120 m/S.
In some embodiments, in step S2, after the reaction product enters the quench zone 4, the reaction product is cooled by direct injection into a cooling medium or by indirect heat exchange.
In some embodiments, in step S2, the reaction product is cooled in the quench zone 4 to a temperature of 300 to 600 ℃.
In some specific embodiments, in step S2, after the reaction product is cooled in the quenching zone 4, the reaction product further enters a secondary cooling zone 5, and the cooling medium sprayed in by the secondary cooling zone 5 further cools the reaction product to 180-250 ℃.
In the following embodiments, when the oxyhydrogen burner 1-1 is operated, hydrogen and a mixture of water vapor and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner 1-1, the trend of the hydrogen and the mixture of water vapor and oxygen in the oxyhydrogen burner 1-1 is schematically shown in fig. 6, in the oxyhydrogen burner 1-1, the hydrogen is introduced into the central channel of the oxyhydrogen burner 1-1, and the mixture of oxygen and water vapor is introduced into the sleeve outside the central channel.
Example 1:
the embodiment provides a reactor for preparing low-carbon olefin by directly heating hydrocarbon and cracking a heat carrier, which is shown in figure 1 and comprises a combustion zone 1, an oxyhydrogen burner 1-1, a high-temperature resistant brick layer 1-2, a combustion zone cylinder 1-3, a mixed pre-reaction zone 2, a shrinkage cone 2-1, a constant diameter nipple 2-2, a first raw material inlet 2-3, a second raw material inlet 2-4, a main reaction zone 3, an expansion cone 3-1, a third raw material inlet 3-2, a main reaction zone outlet 3-3, a quenching zone 4, a quenching zone inlet 4-1, a quenching zone outlet 4-2, a direct cooling medium inlet 4-3, a heat exchange cylinder 4-7 and a secondary cooling zone 5.
The combustion zone 1 comprises a combustion zone cylinder 1-3 with one end closed; the mixing pre-reaction zone 2 is positioned at the downstream of the combustion zone 1, the mixing pre-reaction zone 2 comprises a shrinkage cone 2-1 and an equal-diameter short joint 2-2, the flaring end of the shrinkage cone 2-1 is connected with the unsealed end of the combustion zone cylinder 1-3, and the necking end of the shrinkage cone 2-1 is connected with one end of the equal-diameter short joint 2-2; the main reaction zone 3 is positioned at the downstream of the mixing pre-reaction zone 2, and the main reaction zone 3 comprises an enlarged conical body 3-1, and the closing end of the enlarged conical body 3-1 is connected with the other end of the constant diameter nipple 2-2; the quenching zone 4 is positioned at the downstream of the main reaction zone 3, the quenching zone 4 comprises a heat exchange cylinder 4-7, one end of the heat exchange cylinder 4-7 is connected with the flaring end of the expansion cone 3-1, and the heat exchange cylinder 4-7 is provided with a direct cooling medium inlet 4-3; the secondary cooling zone 5 is located downstream of the quenching zone 4, the quenching zone outlet 4-2 is connected to the secondary cooling zone 5, the secondary cooling zone 5 is provided with a quench cooler through which a cooling medium may be injected and cool the cracked product from the quenching zone 4.
The oxyhydrogen burner 1-1 is provided with 5 oxyhydrogen burners, 1 oxyhydrogen burner 1-1 is arranged at the central position of the closed end of the combustion zone cylinder 1-3, and the other 4 oxyhydrogen burners 1-1 are arranged on the side wall of the combustion zone cylinder 1-3 at equal intervals around the central axis of the combustion zone cylinder 1-3. The oxyhydrogen burner 1-1 arranged on the side wall of the combustion zone cylinder 1-3 is operated, and the included angle formed by the central line of flame sprayed by the oxyhydrogen burner and the circumferential tangent line of the side wall of the combustion zone cylinder 1-3 is 120 degrees. The oxyhydrogen burner 1-1 arranged at the central part of the closed end of the combustion zone cylinder 1-3 is operated with the center line of flame sprayed out parallel to the center axis of the combustion zone cylinder 1-3.
The inner wall of the combustion zone cylinder 1-3 is provided with a high temperature resistant brick layer 1-2.
The first raw material inlets 2-3 are provided with 4, and the 4 first raw material inlets 2-3 are arranged at equal intervals on the side wall of the shrinkage cone 2-1 around the central axis of the shrinkage cone 2-1. The first raw material inlet 2-3 is vertically arranged at the side wall of the shrinkage cone 2-1.
The number of the second raw material inlets 2-4 is 4, and the 4 second raw material inlets 2-4 are arranged on the side wall of the equal-diameter nipple 2-2 at equal intervals around the central axis of the equal-diameter nipple 2-2. The included angle between the central axis of the second raw material inlet 2-4 and the side wall of the equal-diameter nipple 2-2 is 90 degrees.
The third raw material inlets 3-2 are provided in 4, and the 4 third raw material inlets 3-2 are arranged on the side wall of the expansion cone 3-1 at equal intervals around the central axis of the expansion cone 3-1. The central axis of the third raw material inlet 3-2 and the side wall of the expansion cone 3-1 have an included angle of 90 degrees.
The included angle between the side wall of the equal-diameter short section 2-2 and the side wall of the expansion cone 3-1 is 150 degrees. The included angle between the side wall of the shrinkage cone 2-1 and the side wall of the combustion zone cylinder 1-3 is 120 degrees.
In this embodiment, the quenching zone 4 is a direct quenching mode, as shown in fig. 1, the quenching zone inlet 4-1 is connected with the main reaction zone outlet 3-3, cooling mediums are sprayed through the direct cooling medium inlet 4-3, 4 direct cooling medium inlets 4-3 are equally spaced around the central axis of the heat exchange cylinder 4-7, the cooling mediums are quenching oil, and after the quenching oil is mixed with the reaction mixture, the mixture enters the secondary cooling zone 5 for further cooling.
Example 2:
single reactor for producing 10 ten thousand tons of ethylene in one year:
in this example, the reactor of example 1 was used to directly heat and crack the condensate to produce light olefins. The specifications of the condensate are shown in table 1:
table 1 example 2 specification table for condensate
| Project | Data |
| Density (20 ℃ C.)/(kg/m) 3 ) | 789.7 |
| Kinematic viscosity (40 ℃ C.))/(mm 2 /s) | 2.299 |
| Sulfur content/% | 0.0143 |
| Pour point/. Degree.C | 19 |
| Residual carbon/% | 0.05 |
| Flash point/. Degree.C | Flashing at normal temperature |
| Characteristic factor K | 12.76 |
| Carbon content/% | 83.18 |
| Hydrogen content/% | 14.85 |
The method for preparing the low-carbon olefin by directly heating and cracking the condensate oil comprises the following steps:
s1: the oxyhydrogen burner 1-1 is started, hydrogen and a mixture of water vapor and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner 1-1, the hydrogen is combusted, and the generated water vapor enters the combustion zone cylinder 1-3;
s2: the obtained high-temperature steam sequentially flows through a shrinkage cone 2-1 and an equal-diameter nipple 2-2, is sequentially mixed with cracking raw materials from a first raw material inlet 2-3 and a second raw material inlet 2-4, partial cracking raw materials undergo a cracking reaction, then the materials enter an expansion cone 3-1, are mixed with the cracking raw materials from a third raw material inlet 3-2 and further react, the reaction products enter a quenching zone 4, 180 ℃ quenching oil is sprayed into the quenching zone 4 through a direct cooling medium inlet 4-3, the cracking gas is fully mixed with the quenching oil in the quenching zone 4, the quenching oil cools the high-temperature cracking gas to 350 ℃, the cracking reaction is terminated to obtain target products, and the target products enter a secondary cooling zone 5 for further cooling. The temperature of the mixture at the quench zone outlet 4-2 is controlled by controlling the amount of quench oil injected.
In step S1, the hydrogen flow rate: 2220kg/hr, oxygen flow: 15996kg/hr, steam flow: 59040kg/hr.
In the step S2, the first raw material inlet 2-3, the second raw material inlet 2-4 and the third raw material inlet 3-2 are filled with pyrolysis raw materials, and meanwhile atomization water vapor is also filled, wherein the mass ratio of the atomization water vapor to the pyrolysis raw materials is 0.2:1. the residence time of the material in the expansion cone 3-1 is 0.05s, and the material flow rate at the equal-diameter short section 2-2 is 80m/s.
As shown in fig. 3, the hydrogen flow rate: 2220kg/hr, oxygen flow: 15996kg/hr, steam flow: 59040kg/hr, mixing oxygen with water vapor, feeding into oxyhydrogen burner 1-1, mixing with hydrogen in oxyhydrogen burner 1-1, and burning to generate high-temperature water vapor at 1300deg.C. Spraying condensate oil into the mixing pre-reaction zone 2, wherein the flow rate of the condensate oil is 36800kg/hr, mixing the condensate oil with high-temperature steam, directly transferring heat to the condensate oil by the high-temperature steam, quickly raising the temperature of the condensate oil to 830-860 ℃ and quickly carrying out cracking reaction to produce pyrolysis gas, and the temperature of the pyrolysis gas at the outlet 3-3 of the main reaction zone is about 800 ℃. Quenching oil is sprayed into the quenching zone 4 to cool the pyrolysis gas to 350 ℃, and then the mixture enters a subsequent system for further separation.
Table 2 comparative table of product distribution of condensate direct pyrolysis and steam pyrolysis using conventional tube furnace
| Distribution of product (wt%) | Direct thermal pyrolysis | Traditional steam cracking |
| Hydrogen gas | 0.98 | 0.92 |
| Methane | 12.97 | 14.88 |
| Ethylene | 34.10 | 32.11 |
| Ethane (ethane) | 2.86 | 3.80 |
| Propylene | 17.11 | 16.06 |
| Propane | 0.38 | 0.46 |
| Mixed carbon four | 11.23 | 9.64 |
| Mixed carbon five | 4.86 | 4.21 |
| Carbon six + | 15.51 | 17.92 |
| Totalizing | 100.00 | 100.00 |
Under the process parameters, the technology of the embodiment can produce 10.02 ten thousand tons of ethylene and 5.04 ten thousand tons of propylene annually. As can be seen from Table 2, when the condensate oil is cracked, the yield of ethylene and propylene is improved by 6.2% and 6.5% respectively by adopting the process technology compared with the traditional steam cracking technology, and the economic benefit is obvious.
Example 3:
single reactor for producing 10 ten thousand tons of ethylene in one year:
the reactor of example 1 was used to directly heat and crack crude oil to produce light olefins. The specifications of crude oil are shown in table 3:
TABLE 3 specification sheet of crude oil used in example 3
| Project | Data |
| Density (20 ℃ C.)/(kg/m) 3 ) | 860.4 |
| Kinematic viscosity (40 ℃ C.)/(mm 2 /s) | 5.8 |
| Sulfur content/% | 0.031 |
| Pour point/. Degree.C | 30 |
| Residual carbon/% | 0.22 |
| Characteristic factor K | 11.8 |
| Carbon content/% | 85.37 |
| Hydrogen content/% | 12.45 |
The method comprises the following steps:
s1: the oxyhydrogen burner 1-1 is started, hydrogen and a mixture of water vapor and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner 1-1, the hydrogen is combusted, and the generated water vapor enters the combustion zone cylinder 1-3;
S2: the obtained high-temperature steam sequentially flows through a shrinkage cone 2-1 and an equal-diameter nipple 2-2, is sequentially mixed with cracking raw materials from a first raw material inlet 2-3 and a second raw material inlet 2-4, partial cracking raw materials undergo a cracking reaction, then the materials enter an expansion cone 3-1, are mixed with the cracking raw materials from a third raw material inlet 3-2 and further react, the reaction products enter a quenching zone 4, 180 ℃ quenching oil is sprayed into the quenching zone 4 through a direct cooling medium inlet 4-3, the cracking gas is fully mixed with the quenching oil in the quenching zone 4, the quenching oil cools the high-temperature cracking gas to 350 ℃, the cracking reaction is terminated to obtain target products, and the target products enter a secondary cooling zone 5 for further cooling. The temperature of the mixture at the quench zone outlet 4-2 is controlled by controlling the amount of quench oil injected.
In step S1, the hydrogen flow rate: 2910kg/hr, oxygen flow: 20955kg/hr, steam flow: 77320kg/hr.
In the step S2, the first raw material inlet 2-3, the second raw material inlet 2-4 and the third raw material inlet 3-2 are filled with pyrolysis raw materials, and meanwhile atomization water vapor is also filled, wherein the mass ratio of the atomization water vapor to the pyrolysis raw materials is 0.3:1. the residence time of the material in the expansion cone 3-1 is 0.06s, and the material flow rate at the equal-diameter short section 2-2 is 88m/s.
As shown in fig. 3, the hydrogen flow rate: 2910kg/hr, oxygen flow: 20955kg/hr, steam flow: 77320kg/hr, mixing oxygen and water vapor, and feeding into oxyhydrogen burner 1-1, mixing with hydrogen in oxyhydrogen burner 1-1, and burning to obtain high-temperature water vapor at 1300deg.C. Spraying crude oil into the mixing pre-reaction zone 2, mixing the crude oil with high temperature steam at 48250kg/hr, transferring heat directly to the crude oil by the high temperature steam, rapidly heating the crude oil to 850-890 ℃ and rapidly performing cracking reaction to produce cracking gas, and controlling the temperature of the cracking gas at about 790 ℃ at the outlet 3-3 of the main reaction zone. The temperature of the quenching oil injected through the direct cooling medium inlet 4-3 is 195 ℃, the pyrolysis gas is fully mixed with the quenching oil in the quenching zone 4, the temperature after mixing is 350 ℃, and the temperature of the mixture at the quenching zone outlet 4-2 can be controlled by controlling the injected quenching oil quantity. The mixture then enters a subsequent system for further separation.
Table 4 example 3 comparison of product distribution of crude oil direct thermal cracking with steam cracking using conventional tube furnace table
| Distribution of product (wt%) | Direct thermal pyrolysis | Traditional steam cracking |
| Hydrogen gas | 0.67 | 0.64 |
| Methane | 8.67 | 10.15 |
| Ethylene | 25.91 | 24.35 |
| Ethane (ethane) | 2.36 | 2.98 |
| Propylene | 15.06 | 14.12 |
| Propane | 0.34 | 0.38 |
| Mixed carbon four | 11.28 | 10.24 |
| Mixed carbon five | 5.91 | 5.61 |
| Carbon six + | 29.80 | 31.53 |
| Totalizing | 100.00 | 100.00 |
Under the technological parameters, the technology can produce 10.02 ten thousand tons of ethylene and 5.81 ten thousand tons of propylene annually. As can be seen from Table 4, when the crude oil is cracked, the yield of ethylene and propylene is improved by 6.4% and 6.65% respectively by adopting the process technology compared with the traditional steam cracking technology, and the economic benefit is obvious.
Example 4:
annual production of 5 ten thousand tons of ethylene reactor:
the reactor used in this example is the same as that in example 1 except that in this example, the heat exchange cylinder 4-7 of the quench zone 4 of the reactor is provided with 1 indirect heat exchanger 4-6, as shown in fig. 2, the quench zone inlet 4-1 is connected with the main reaction zone outlet 3-3, the indirect heat exchanger 4-6 is a double-sleeve quench heat exchanger, a double-sleeve structure is adopted, the diameter of the heat exchange tube is phi 51mm, the number of the heat exchange tubes is 198, the cooling medium is water, the cooling medium enters from the indirect cooling medium inlet 4-4, and the steam-water mixture is led out from the indirect cooling medium outlet 4-5.
In this example, typical naphtha was subjected to direct thermal cracking to produce light olefins. The specifications of the naphtha are shown in table 5.
Table 5 specification table for example 4 naphtha
| Project | Naphtha (naphtha) |
| Relative Density (20/4 ℃ C.) | 0.69 |
| ASTM distillation | |
| IBP | 40℃ |
| 50vol％ | 85℃ |
| EBP | 170℃ |
| PONA wt％ | |
| Alkanes | ≥70 |
| Wherein n-alkanes | ≥30 |
| Olefins | ≤1 |
| Cycloalkane (CNS) | ≤25 |
| Aromatic hydrocarbons | ≤6 |
The method comprises the following steps:
s1: the oxyhydrogen burner 1-1 is started, hydrogen and a mixture of water vapor and oxygen are respectively and simultaneously introduced into the oxyhydrogen burner 1-1, the hydrogen is combusted, and the generated water vapor enters the combustion zone cylinder 1-3;
s2: the obtained high-temperature steam sequentially flows through a shrinkage cone 2-1 and an equal-diameter short joint 2-2, is sequentially mixed with cracking raw materials from a first raw material inlet 2-3 and a second raw material inlet 2-4, partial cracking raw materials undergo a cracking reaction, then the materials enter an expansion cone 3-1, are mixed with the cracking raw materials from a third raw material inlet 3-2 and further react, a reaction product enters a quenching zone 4, the temperature of the mixture is reduced to 375 ℃ after heat exchange, the reaction is terminated, and a target product is obtained, and then the mixture enters a subsequent secondary cooling zone 5 for further cooling.
In step S1, the hydrogen flow rate: 1256kg/hr, oxygen flow: 9120kg/hr, steam flow: 30060kg/hr.
In the step S2, the first raw material inlet 2-3, the second raw material inlet 2-4 and the third raw material inlet 3-2 are filled with pyrolysis raw materials, and meanwhile atomization water vapor is also filled, wherein the mass ratio of the atomization water vapor to the pyrolysis raw materials is 0.2:1. the residence time of the material in the expansion cone 3-1 is 0.05s, and the material flow rate at the equal-diameter short section 2-2 is 90m/s.
In the step S2, the cooling medium of the quenching zone 4 is water, the temperature of the water is 310 ℃, the pressure is 120Mpa, and the steam-water mixture led out from the indirect cooling medium outlet 4-5 is mixed with steam and water in a mass ratio of 1:9; the temperature of the mixture at quench zone exit 4-2 was 375 ℃.
Wherein the hydrogen flow rate: 1256kg/hr, oxygen flow: 9120kg/hr, steam flow: 30060kg/hr, as shown in FIG. 4, oxygen and water vapor are mixed and fed into oxyhydrogen burner 1-1, and mixed with hydrogen in oxyhydrogen burner 1-1 for combustion to generate high temperature water vapor with a temperature of 1400-1450 ℃. Naphtha is sprayed into the mixed pre-reaction zone 2, the flow rate of the naphtha is 20440kg/hr, the naphtha and high-temperature steam are mixed through the mixed pre-reaction zone 2, the heat is directly transferred to the naphtha by the high-temperature steam, the temperature of the naphtha is rapidly increased to 860-900 ℃ and rapidly subjected to cracking reaction to generate cracking gas, and the temperature of the cracking gas at the outlet 3-3 of the main reaction zone is about 810 ℃.
Then, the pyrolysis gas enters an indirect heat exchanger 4-6, after passing through the indirect heat exchanger 4-6, the waste heat of the pyrolysis gas is recovered for generating high-pressure steam, meanwhile, the pyrolysis gas is cooled to about 380 ℃, then the pyrolysis gas enters a secondary cooling zone 5, quenching oil is sprayed into the pyrolysis gas through an oil quenching device to cool the pyrolysis gas to 220 ℃, and then the pyrolysis gas is sent to a subsequent system for further heat recovery and component separation.
Under the technological parameters, the technology can produce ethylene 5 ten thousand tons and propylene 2.53 ten thousand tons annually. As can be seen from Table 6, when naphtha is cracked, the yield of ethylene and propylene is improved by 6.4% and 7.8% respectively by adopting the process technology compared with the traditional steam cracking technology, and the economic benefit is obvious.
TABLE 6 example 4 direct heating pyrolysis of naphtha compared to product distribution by steam pyrolysis in a conventional tube furnace
| Distribution of product (wt%) | Direct thermal pyrolysis | Traditional steam cracking |
| Hydrogen gas | 1.08 | 1.03 |
| Methane | 14.89 | 16.11 |
| Ethylene | 30.58 | 28.73 |
| Ethane (ethane) | 2.55 | 2.93 |
| Propylene | 15.49 | 14.37 |
| Propane | 0.27 | 0.32 |
| Mixed carbon four | 10.73 | 9.77 |
| Mixed carbon five | 3.95 | 3.61 |
| Carbon six + | 20.46 | 23.13 |
| Totalizing | 100.00 | 100.00 |
Example 5:
a direct heating pyrolysis unit for producing 20 ten thousand tons of ethylene in one year:
as shown in FIG. 5, the reactors of example 4 were used in parallel, and 5 reactors were combined to form a cracking reaction unit of 20 ten thousand tons per year, wherein 4 reactors were in line and 1 reactor was in a scorched or standby state. For a device for producing 100 ten thousand tons of ethylene annually, the requirement of actual production can be met by adopting 5 cracking reaction units (equivalent to six traditional ethylene cracking furnaces), and the device for producing the low-carbon olefin by direct heating cracking is large-sized.
Example 6:
the reactors of example 3 were used in parallel, and a group of 2 reactors was used, whereby a cracking reaction unit of 20 ten thousand tons per year could be easily formed. For a 120 ten thousand ton ethylene device, 7 cracking reaction units can meet the actual production requirement, and the device for producing the low-carbon olefin by direct heating and cracking is large.
Example 7:
compared with the embodiment 1, most parts of the heat-resistant brick layer are the same, except that in the embodiment, the high-temperature-resistant brick layer on the inner wall of the combustion zone cylinder 1-3 is changed into a water jacket structure, and circulating cooling water is introduced between jackets, so that the effect of protecting the inner wall of the combustion zone cylinder 1-3 is achieved.
Example 8:
most of the same as in example 2, except that in this example the condensate was changed to equal flow of ethane.
Example 9:
most of the same as in example 2, except that in this example, the condensate was changed to equal flow propane.
Example 10:
most of the same as in example 2 except that in this example the condensate was changed to equal flow of n-butane.
Example 11:
most of the same as in example 2, except that in this example, the condensate was changed to an equal flow of liquefied petroleum gas.
Example 12:
most of the same as in example 2, except that in this example, the condensate was changed to equal flow of carbon five.
Example 13:
most of the same as in example 2, except that in this example, the condensate was changed to an equal flow of diesel.
Example 14:
most of the same as in example 2, except that in this example, the condensate was changed to an equal flow rate hydrogenated tail oil.
Example 15:
most of the same as in example 2, except that in this example, condensate was changed to an equal flow rate residuum.
Example 16:
in comparison with example 2, which is largely identical, except that in this example, the "mass ratio of atomizing steam to cracking feedstock was 0.2:1 "instead" the mass ratio of the atomizing water vapor to the cracking raw material is 0.1:1".
Example 17:
in comparison with example 2, which is largely identical, except that in this example, the "mass ratio of atomizing steam to cracking feedstock was 0.2:1, "instead," the mass ratio of the atomizing water vapor to the cracking raw material is 5:1".
Example 18:
in comparison with example 2, the same operation was carried out in the same manner as in example 2 except that the "residence time was 0.05s" instead of the "residence time of 0.01s".
Example 19:
in comparison with example 2, the same operation was carried out in the same manner as in example 2 except that the "residence time was 0.05s" was changed to "residence time was 0.5s".
Example 20:
in comparison with example 2, the same operation was carried out in the same manner as in example 2 except that in this example, the flow rate of the material was changed to 80 m/s.
Example 21:
In comparison with example 2, the same operation was conducted in the same manner as in example 2 except that the flow rate of the material was changed to 200 m/s.
Example 22:
compared with example 2, most of them are the same, except that in this example, the volume ratio of oxygen and water vapor introduced in step S1 is adjusted to 1:10.
the previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.
Claims (10)
1. A reactor for preparing low-carbon olefin by directly heating hydrocarbon with a heat carrier is characterized by comprising the following components:
combustion zone (1) for providing high temperature water vapour: the combustion zone comprises a combustion zone cylinder body (1-3) with one end closed, wherein the combustion zone cylinder body (1-3) is provided with an oxyhydrogen burner (1-1);
A mixing pre-reaction zone (2) for mixing the feedstock and the high-temperature water vapor located downstream of the combustion zone (1): the combustion zone cylinder comprises a shrinkage cone (2-1) and an equal-diameter short joint (2-2), wherein the flaring end of the shrinkage cone (2-1) is connected with the unsealed end of the combustion zone cylinder (1-3), the necking end of the shrinkage cone (2-1) is connected with one end of the equal-diameter short joint (2-2), the shrinkage cone (2-1) is provided with a first raw material inlet (2-3), and the equal-diameter short joint (2-2) is provided with a second raw material inlet (2-4);
a main reaction zone (3) downstream of the mixing pre-reaction zone (2): the device comprises an expansion cone (3-1), wherein the closing end of the expansion cone (3-1) is connected with the other end of the constant diameter nipple (2-2), and the expansion cone (3-1) is provided with a third raw material inlet (3-2);
a quench zone (4) downstream of the main reaction zone (3) for stopping the cracking reaction.
2. The reactor for preparing low-carbon olefin by directly heating hydrocarbon through pyrolysis according to claim 1, wherein the oxyhydrogen burner (1-1) is provided with a plurality of oxyhydrogen burners, and the oxyhydrogen burners (1-1) are arranged on the side wall of the combustion zone cylinder (1-3) or on the central part of the closed end of the combustion zone cylinder (1-3) at equal intervals around the central axis of the combustion zone cylinder (1-3).
3. The reactor for preparing low-carbon olefin by directly heating and cracking hydrocarbon by using heat carrier according to claim 1, wherein the inner wall of the combustion zone cylinder (1-3) is also provided with a high-temperature resistant heat insulation material layer.
4. The reactor for preparing low-carbon olefin by directly heating hydrocarbon and cracking with heat carrier according to claim 1, wherein the combustion zone cylinder (1-3) has a double-layer jacket structure, and a cooling medium is introduced into the jacket.
5. The reactor for preparing low-carbon olefin by directly heating hydrocarbon cracking by using a heat carrier according to claim 1, wherein a plurality of first raw material inlets (2-3) are arranged, and the plurality of first raw material inlets (2-3) are arranged on the side wall of the shrinkage cone (2-1) at equal intervals around the central axis of the shrinkage cone (2-1);
the second raw material inlets (2-4) are arranged in a plurality, and the second raw material inlets (2-4) are arranged on the side wall of the equal-diameter nipple (2-2) at equal intervals around the central axis of the equal-diameter nipple (2-2);
the third raw material inlets (3-2) are arranged in a plurality, and the plurality of third raw material inlets (3-2) are arranged on the side wall of the expansion cone (3-1) at equal intervals around the central axis of the expansion cone (3-1).
6. Reactor for the direct heating hydrocarbon cracking production of light olefins according to claim 1, characterized in that the quenching zone (4) comprises a heat exchange cylinder (4-7), one end of the heat exchange cylinder (4-7) is connected with the flaring end of the expansion cone (3-1), the heat exchange cylinder (4-7) is provided with a direct cooling medium inlet (4-3) or an indirect heat exchanger (4-6).
7. The method for preparing the low-carbon olefin by directly heating the hydrocarbon by using the heat carrier is characterized by being implemented by adopting the reactor for preparing the low-carbon olefin by directly heating the hydrocarbon by using the heat carrier according to any one of claims 1-6, and comprises the following steps:
s1: starting the oxyhydrogen burner (1-1), respectively and simultaneously introducing hydrogen and oxygen into the oxyhydrogen burner (1-1), burning the hydrogen, and enabling the generated high-temperature steam to enter the combustion zone cylinder (1-3);
s2: the obtained high-temperature steam sequentially flows through the shrinkage cone (2-1) and the constant diameter nipple (2-2), is sequentially mixed with cracking raw materials from the first raw material inlet (2-3) and the second raw material inlet (2-4), partial cracking raw materials undergo a cracking reaction, then the materials enter the expansion cone (3-1), are mixed with the cracking raw materials from the third raw material inlet (3-2) and further react, and the reaction product enters the quenching zone (4) to be cooled, so that the target product is obtained.
8. The method for preparing low-carbon olefin by direct heating hydrocarbon cracking with heat carrier as claimed in claim 7, wherein in step S1, while oxygen is introduced, water vapor is also introduced, and the mixing volume ratio of oxygen to water vapor is 1: (0 to 10), and is not 1:0;
in the step S1, the temperature of the high-temperature steam at the outlet of the combustion zone cylinder (1-3) is 1000-1500 ℃.
9. The method for preparing low-carbon olefin by direct heating hydrocarbon cracking with heat carrier according to claim 7, wherein in step S2, the cracking raw material is one or more of ethane, propane, n-butane, liquefied petroleum gas, carbon five, naphtha, diesel oil, hydrogenated tail oil, condensate oil, residual oil or crude oil;
in the step S2, the first raw material inlet (2-3), the second raw material inlet (2-4) and the third raw material inlet (3-2) are simultaneously filled with pyrolysis raw materials, and atomized water vapor is also filled, wherein the mass ratio of the atomized water vapor to the pyrolysis raw materials is (0.1-5): 1, a step of;
in the step S2, the residence time of the material in the expansion cone (3-1) is 0.01-0.5S, and the temperature of the reaction product at the outlet (3-3) of the main reaction zone is 600-900 ℃;
in the step S2, the material flow rate at the equal-diameter short section (2-2) is 50-200 m/S.
10. The method for preparing low-carbon olefin by direct heating hydrocarbon cracking with heat carrier according to claim 7, wherein in step S2, after the reaction product enters the quenching zone (4), the reaction product is cooled by directly spraying cooling medium or by indirect heat exchange;
in step S2, the reaction product is cooled by the quenching zone (4) and the temperature is 300-600 ℃.
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