Production of vinyl chloride monomers

Abstract

A process for the manufacture of vinyl chloride monomer (VCM) is provided, the process comprising thermally cracking dichloroethane (EDC) to produce a VCM-containing gaseous product, in which a rotating apparatus (100) is used to generate an amount of thermal energy required to heat an EDC-containing process fluid stream to a temperature at which the cracking reaction occurs, and to transfer the thermal energy to the EDC-containing process fluid. Also provided is the use of a VCM production plant and a rotating plant for the production of vinyl chloride monomers from EDC by thermal cracking.

Description

Technical Field

[0001] The present invention generally relates to the production of vinyl chloride monomer from ethylene dichloride. In particular, the present invention relates to the thermal cracking of ethylene dichloride to vinyl chloride monomer using a rotary device. Background Art

[0002] Vinyl chloride monomer (VCM) or vinyl chloride is one of the most important commodity chemicals. The main use of vinyl chloride monomer is in the manufacture of polyvinyl chloride (PVC), where VCM is used as a monomer building block for PVC polymers. PVC is currently the second most abundant polymer in the world, second only to polyethylene, with global PVC production of approximately 60 million tons per year. Approximately 96% of vinyl chloride monomer is used in the production of polyvinyl chloride.

[0003] In the early twentieth century, VCM was mainly produced from acetylene, which can be catalyzed by hydrochloric acid to form VCM (see Formula 1).

[0004] (1) C2H2+HCl→CH2=CHCl

[0005] Due to the high energy requirements of acetylene production and the hazards associated with acetylene handling, the less energy-intensive ethylene dichloride route was developed in the mid-twentieth century. Since then, the ethylene-based route has become mainstream.

[0006] Ethylene-based VCM production is a balanced process, which means that starting from ethylene, chlorine and oxygen, all intermediate products and by-products are recovered in a way that ensures material balance, with only VCM as the final product. The ethylene-based pathway produces 1,2-dichloroethane (EDC) (Equation 2.1) by high temperature chlorination of ethylene, followed by thermal decomposition of EDC to produce VCM and hydrochloric acid (see Equation 2.2).

[0007] (2.1)C2H4+Cl2→ClCH2–CH2Cl

[0008] (2.2)ClCH2–CH2Cl→CH2=CHCl+HCl (ΔH=71kJ / mol)

[0009] The thermal decomposition of EDC is carried out by thermal cracking, which can be carried out in the liquid or gas phase. However, processes based on the liquid phase are not industrially important because expensive chlorine is lost in the form of salts when EDC is treated with alkaline solutions. The treatment of aqueous process streams is also associated with several environmental issues. Therefore, the gas phase route by thermal cracking or pyrolysis is the most suitable industrial route for VCM production.

[0010] The gas phase thermal cracking (pyrolysis) of EDC to VCM consists of a complex series of chlorine-catalyzed free radical and molecular reactions. Although Equation 2.2 represents the molecular reactions (overall reactions), it does not cover all the chemical processes that occur during the thermal decomposition of EDC into VCM-containing products.

[0011] exist Figure 2A A conventional pyrolysis furnace 200 for EDC cracking is shown in FIG. Gas phase pyrolysis is highly endothermic; therefore, it is usually carried out in tubular coils made of chromium / nickel alloy arranged in the firebox (radiant section) of the pyrolysis furnace. Depending on the design, 16 to 128 coils can be arranged in the firebox. The pyrolysis furnace is usually lined with refractory materials. The EDC stream passes through the radiant coils, where reactions occur to produce VCM, hydrogen chloride (HCl) and by-products such as acetylene. The temperature of the exhaust gas is rapidly reduced (product gas quenching) to avoid further decomposition of VCM and to minimize the formation of by-products as well as coke and heavy tar. In most processes, the cracked gas is cooled in a quench tower, and the condensed and cooled EDC is recycled at high speed in the quench tower. In some cases, quenching is carried out in two stages, first indirectly cooled in a transport line heat exchanger, and then directly quenched. This allows heat recovery to be used for other process levels.

[0012] The heat required for this set of endothermic pyrolysis reactions is provided by the combustion of fuel in the firebox burners. The furnace can be equipped with a single or multiple burners. In most cases, the burners are fueled by natural gas. The heat carried away by the flue gases is recovered in the convection section of the furnace, which is usually located above the firebox and consists of a series of tube bundles. The heat recovered in the convection section can be used, for example, to preheat (evaporate) the hydrocarbon feedstock (about 200°C) and the dilution medium.

[0013] Conventional pyrolysis furnaces for thermal cracking of ethylene dichloride operate at 50-60% EDC conversion, with a gas residence time of about 10-30 seconds, a pressure of 6-35 atm (0.6-3.5 MPa), and a gas temperature of 480-550° C., and in some cases 500-530° C. Higher temperatures increase EDC conversion but result in a decrease in selectivity. Operating conditions are typically selected based on a tradeoff between, for example, utility costs, production rate, and frequency of downtime.

[0014] Although it is possible to achieve VCM product selectivity of up to 99%, in practice, EDC conversion remains modest. This is because of the formation of foulants and byproducts during the pyrolysis process due to the high material throughput, resulting in severe inefficiencies. For example, the formation of coke is inevitable in pyrolysis, and it is necessary to shut down the entire plant regularly to remove the coke. Other gas phase byproducts, such as chloroprene (C4H5Cl) and butadiene (C4H6), can also cause difficulties for downstream distillation columns. The conversion rate can be slightly increased by adding a small amount (about 1200ppm) of the oxychlorination byproduct carbon tetrachloride (CCl4) to the EDC feed. Carbon tetrachloride increases the formation of free chlorine radicals, which can be used to increase the conversion rate to about 60%. However, chlorine radicals are also promoters for the formation of undesirable coke.

[0015] Although there are a variety of furnace designs available, most VCM producers have developed their own proprietary furnace technology to achieve optimal yields and reduce the frequency of shutdowns for tube decoking. However, tube pyrolysis furnaces are still fairly large and complex facilities with a high greenhouse gas emissions burden.

[0016] In this regard, there remains a need for innovations in the field of vinyl chloride (monomer) manufacturing technology in view of addressing the challenges associated with increasing feed-to-product conversion and reducing greenhouse gas emissions in an efficient and environmentally friendly manner. Summary of the invention

[0017] The object of the present invention is to solve or at least alleviate each of the problems caused by the limitations and disadvantages of the related art. This object is achieved by various embodiments of a method for manufacturing vinyl chloride monomer (VCM), related production equipment and uses. In one aspect, according to the definition in independent claim 1, a method for manufacturing vinyl chloride monomer (VCM) is provided.

[0018] In an embodiment, the method comprises: thermally cracking ethylene dichloride (EDC) to produce a gaseous product containing VCM, wherein a rotating device is used to generate an amount of heat energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs, and the heat energy is transferred to the process fluid containing EDC, the rotating device comprising: a rotor having a plurality of rotor blades arranged in at least one row on the circumference of a rotor hub mounted to a rotor shaft; a plurality of fixed guide vanes arranged in one or more rows upstream of the rotor blades; and a fixed diffuser arranged downstream of the rotor blades, wherein the rotor, the fixed guide vanes and the diffuser are enclosed in a duct formed between at least one inlet and at least one outlet in the rotating device, and wherein, in the rotating device, the amount of heat energy is generated by means of a series of energy conversions occurring when a fluid medium flow propagating in a duct located between one or more inlets and one or more outlets passes successively through the fixed guide vanes, the rotor blades and the diffuser, respectively.

[0019] In an embodiment, the method comprises thermally cracking EDC in a rotating device, wherein the cracking reaction is initiated in a process fluid containing EDC propagating through the rotating device by directly adding an amount of thermal energy required for the cracking reaction to occur to the process fluid stream containing EDC.

[0020] In an embodiment, the method comprises thermally cracking EDC in a pyrolysis furnace suitable for the purpose of thermal cracking EDC, the method further comprising:

[0021] - in the rotating device, generating a heated fluid medium by adding said amount of thermal energy to the fluid medium propagating through the rotating device, and

[0022] - Using the fluid medium as a carrier to transfer thermal energy to the pyrolysis furnace and to heat the EDC-containing process fluid stream flowing through the pyrolysis furnace to a temperature at which a cracking reaction occurs.

[0023] In an embodiment, the heated fluid medium used as a heat energy carrier is any one of air, nitrogen, steam, flue gas discharged from a pyrolysis furnace, and any combination thereof. The pyrolysis furnace may be any cracking furnace suitable for thermal cracking of a feed containing ethylene dichloride.

[0024] In an embodiment, the method comprises connecting at least two rotating devices into a system, wherein a first device is assigned a preheater function for (pre)heating an EDC-containing process fluid and a second device arranged downstream of the first device is assigned a thermal cracking furnace function.

[0025] In an embodiment, the method further comprises conducting an amount of input energy into at least one rotating device, wherein an amount of thermal energy added to the flow of fluid medium propagating through the rotating device is regulated by adjusting the amount of input energy conducted into the at least one rotating device. In an embodiment, the input energy is electrical energy. In an embodiment, the amount of electrical energy conducted into the at least one rotating device as input energy is in the range of approximately 5% to 100%.

[0026] In an embodiment, the amount of electrical energy conducted as input energy into the at least one rotating device can be obtained from a renewable energy source or a combination of different energy sources, optionally can be obtained from a renewable energy source.

[0027] In an embodiment, the method includes adjusting the velocity and / or pressure of a flow of a fluid medium propagating through a rotating device to produce conditions under which an amount of kinetic energy sufficient to increase the temperature of the fluid medium to a predetermined value is added to the flow of the fluid medium by the rotating blades of the rotor as the flow of the fluid medium exits the at least one row of rotor blades at a supersonic speed and passes through a fixed diffuser wherein the flow decelerates and dissipates the kinetic energy as internal energy of the fluid medium, thereby adding the amount of thermal energy to the flow of the fluid medium.

[0028] In an embodiment, in said method, said amount of thermal energy added to the flow of fluid medium propagating through the device is generated by means of a shock wave system generated during the successive propagation of said flow of fluid medium in a controlled manner through said plurality of rows of fixed guide vanes, said row of rotor blades and a fixed diffuser, respectively.

[0029] In one aspect, there is provided a method for producing polyvinyl chloride (PVC), as defined in independent claim 13. The method comprises producing PVC by polymerizing a VCM article obtained using the method according to the previous aspect.

[0030] In one aspect, according to the definition in independent claim 14, there is provided a VCM production plant for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking.

[0031] In one aspect, according to the definition of independent claim 23, there is provided the use of said rotating device in the production of vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking.

[0032]

[0046] In accordance with each of the specific embodiments of the present invention, the present invention is useful for a number of reasons.

[0033] In general, the present invention aims to improve the conventional EDC cracking process by integrating the rotating device described below into the process. The following problems associated with existing EDC cracking technology can be improved:

[0034] - Improvement of the selectivity of the main reaction (VCM production) by suppressing the formation of by-products.

[0035] -Achieve single-pass output significantly exceeding conventional EDC furnaces.

[0036] -The size of the equipment used for EDC cracking can be greatly reduced.

[0037] - Reduce the formation of coke and other foulants and extend the operating time of the EDC cracking reactor by inhibiting coke formation.

[0038] - The energy efficiency of the EDC cracking process (energy used per mass unit of VCM produced) is significantly improved.

[0039] - Reduction of greenhouse gas emissions, such as CO2 emissions, per mass unit of VCM produced through the electrification of EDC cracking / VCM production.

[0040] In general, the rotating apparatus used in the presently disclosed methods allows heat to be input directly or indirectly into an EDC-containing process fluid, wherein the amount of heat input into the process is sufficient to initiate and maintain the cracking reaction of ethylene dichloride at a predetermined level to produce vinyl chloride (monomer).

[0041] Direct heating involves propagating a process fluid containing EDC through a rotating device. In this way, heating of the process fluid is achieved extremely quickly because the need to transfer heat from an external heater through the reactor wall is eliminated. The absence of such external heating results in lower reactor surface temperatures, which in turn results in a much lower coke yield during the cracking process. As a result, the cracking furnace can operate for a longer time between decoking shutdowns. In addition, direct heating allows the temperature of the process fluid to be raised above the temperature of conventional EDC cracking (500-550°C). This increases the rate of the EDC cracking reaction, thereby shortening the residence time of the reactants in the process space. As a result, the size of the EDC cracking furnace can be greatly reduced. Alternatively, the single-pass conversion rate in a standard (non-reduced) size device can be increased.

[0042] Indirect heating involves heating a fluid other than the EDC-containing feed in a rotating device and further using said fluid as a heat transfer medium to input heat energy into the EDC pyrolysis furnace. This method allows any existing EDC cracking furnace to be converted into a low-emission, energy-efficient furnace. Replacing fired heaters with rotating devices in conventional furnaces does not require major changes to the infrastructure and is therefore very cost-effective.

[0043] The indirect heating method is also associated with improved cracking temperature control. In a fired heater, the temperature of the flame is very high, ranging from 1800-2200°C, depending on the fuel and (air) preheat. These extremely high temperatures will heat the furnace coils accordingly and lead to accelerated coking. By applying rotating equipment technology, the temperature of the EDC cracking furnace can be kept at a lower level and the input heat can be distributed more evenly throughout the furnace. This leads to a reduction in the tendency to coke and thus increases the conversion rate to well above the typical single-pass conversion value of about 60%.

[0044] The invention also allows reducing greenhouse gas (CO, CO2, NOx, SOx) and particle emissions produced in conventional EDC cracking. This can be achieved by electrically driving the rotary device and integrating it into a conventional EDC cracking unit in a closed or semi-closed heating circuit; thus, the energy efficiency of the process is improved by reducing flue gas heat losses. In conventional heaters, flue gases can only be partially recycled.

[0045] The expression "a number" herein refers to any positive integer starting from one (1), such as one, two or three. The expression "a plurality" herein refers to any positive integer starting from two (2), such as two, three or four. The terms "first" and "second" are used herein only to distinguish one element from another and do not indicate any particular order or importance unless expressly stated otherwise.

[0046] In this disclosure, the terms "thermal cracking" and "pyrolysis" may be used interchangeably.

[0047] In this disclosure, the term "gasification" is used to indicate that a substance is converted into a gaseous form by any possible means.

[0048] Various embodiments of the invention will become apparent by consideration of the detailed description and accompanying drawings.

[0049] BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1A and 1B is a schematic diagram of a VCM production method and related production apparatus according to an embodiment;

[0051] Figure 2A A conventional pyrolysis furnace is schematically shown;

[0052] Figure 2B Schematically shows a VCM production method and related production device according to an embodiment;

[0053] Figure 3 Schematically shows a VCM production method and related production device according to an embodiment;

[0054] Figure 4A-4Care vertical cross-sectional views of rotating devices 100 ( 100A, 100B, and 100C, respectively) configured to implement a method according to an embodiment;

[0055] 5 to 9 show temperature curves and mass fraction curves obtained in Exemplary Cases 1-5. DETAILED DESCRIPTION

[0056] Detailed embodiments of the present invention are disclosed herein with reference to the accompanying drawings.

[0057] Figure 1A , Figure 1B , Figure 2B and Figure 3 The basic layout of a method for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by a thermal cracking process according to an embodiment of the present invention and the basic layout of a related VCM production device are schematically shown. Therefore, the VCM production method and the VCM production device generally configured to implement the method are represented by a common reference numeral 101.

[0058] The VCM production unit may further be integrated into an industrial facility, plant or any industrial system (not shown) comprising equipment designed to perform an industrial process or a series of industrial processes, the industrial process being intended to obtain vinyl chloride (monomer) from a feed containing ethylene dichloride. The industrial facility referred to may include additional equipment or facilities and / or power sources for the manufacture, extraction and / or refining of related materials (e.g., raw materials, intermediates, products and any auxiliary chemicals used in the process). The industrial facility may, for example, include a facility for chlorination of ethylene to produce 1,2-dichloroethane (EDC) and / or a facility for producing polyvinyl chloride (PVC) by polymerization of VCM.

[0059] In one aspect, the present invention relates to a method for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermally cracking (pyrolyzing) an EDC feedstock to produce a gaseous product containing VCM. A rotating device 100, 100-1, 100-2 is used to generate the amount of heat energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs, and to transfer the heat energy to the process fluid stream containing EDC.

[0060] Please refer to Figure 4A , Figure 4B and Figure 4C , which schematically shows different embodiments of a rotating device 100 (respectively 100A, 100B and 100C). It is further assumed that, based on the following description, a skilled person is able to practice the present invention using different configurations of the rotating device, including those configurations not explicitly disclosed herein.

[0061] A rotating device 100 configured to directly or indirectly heat a process fluid stream containing EDC includes: a rotor having a plurality of rotor blades arranged in at least one row on the circumference of a rotor hub mounted on a rotor shaft; a plurality of fixed guide vanes arranged in one or more rows upstream of the rotor blades; and a fixed diffuser arranged downstream of the rotor blades. The rotor and the fixed components are enclosed in a conduit formed between at least one inlet and at least one outlet of the rotating device. In the rotating device, the amount of thermal energy required to directly or indirectly heat the process fluid stream containing EDC to a temperature at which a cracking reaction occurs is generated by a series of energy conversions that occur when a fluid medium flow propagating in a conduit between the one or more inlets and the one or more outlets passes successively through the fixed guide vanes, the rotor blades, and the fixed diffuser, respectively.

[0062] In the VCM production device, the device 100 (100A, 100B and 100C) can be provided as a stand-alone device or as a plurality of devices arranged in series (in sequence) and / or in parallel (in an array). The operating concept of the device 100 is that it is able to transfer the mechanical energy of a rotating shaft to a fluid medium and convert the mechanical energy into the internal energy of the fluid through a set of fixed and rotating components in multiple working stages. When the fluid flow dissipates its kinetic energy as the internal energy of the fluid, it provides a certain amount of thermal energy (heat) to the fluid flow, thereby increasing the temperature of the fluid. The aerodynamic design of the device 100 can vary.

[0063] Figure 4A An axial flow device 100, 100A is shown in which the rotating guide vanes and the stationary guide vanes are enclosed in a substantially tubular casing, as in the grant et al., as described in U.S. Pat. No. 9,234,140. Figure 4B The configuration 100, 100B described in U.S. Pat. No. 10,744,480 to Xu and Rosic is shown. Figure 4C In the illustrated configuration 100, 100C, the process fluid propagates between the inlet and the outlet along a flow path established according to a substantially spiral trajectory formed within a substantially annular housing, wherein the fluid flow successively passes through a plurality of rows of fixed guide vanes, rotor blades, and fixed diffuser vanes. Such an apparatus is discussed in detail in U.S. Pat. No. 9,234,140 of et al. Alternatively, the method according to the embodiment can also be implemented using a rotating device configured to achieve fluid flow along a flow path established by means of a fluid medium flow in the form of two spirals rolled into a left-right vortex ring, as described in U.S. Pat. No. 7,232,937 to Bushuev (not shown). The above document is considered to be incorporated herein by reference.

[0064] In all configurations 100A, 100B and 100C, the device 100 comprises a rotor system, which is hereinafter referred to as a rotor, comprising a rotor shaft 1 arranged along a horizontal (longitudinal) axis XX' and a plurality of rotor blades (also referred to as working blades) arranged in at least one row on the circumference of a rotor hub or rotor disk 3A mounted on the rotor shaft. The plurality of rotor blades arranged in (blade) rows constitutes a rotor blade assembly or rotor blade cascade 3.

[0065] The rotary machine also includes a drive system including at least one motor and associated drive means to drive the rotor. Figure 4A In the embodiment, the drive system is indicated by reference numeral 20. In an embodiment, the motor is an electric motor (i.e., a device capable of transferring energy from a power source to a mechanical load). Additionally or alternatively, the rotating device may be directly driven by, for example, a gas turbine or a steam turbine or any other suitable drive device.

[0066] The device 100 also includes a fixed (stator) part (e.g., a housing 6) formed by a plurality of structures defining a reaction space, and a plurality of fixed guide vanes arranged in at least one row adjacent to a corresponding row of rotor blades. The device also includes a fixed diffuser, which can be vaned or vaneless.

[0067] In some configurations, the device comprises a plurality of fixed guide vanes 2 arranged in at least one row upstream of a corresponding row of rotor blades. The fixed guide vanes may be configured as fixed nozzle guide vanes (NGV). In some configurations, the device further comprises a plurality of fixed diffuser guide vanes 4 arranged in at least one row downstream of a corresponding row of rotor blades. The rows of fixed guide vanes form a fixed guide vane cascade 2 and a fixed diffuser guide vane cascade 4, respectively.

[0068] The term "cascade" (a group of blades) refers to a collection of (working) blades mounted on the periphery of a rotor disk / rotor hub or (stationary) blades mounted directly or indirectly on the inner wall of a casing. For clarity, stationary guide vanes are referred to as "guide vanes" in this disclosure.

[0069] The terms "upstream" and "downstream" refer to the spatial and / or functional arrangement of structural parts or components relative to predetermined parts or components, so that at least one rotor blade row is substantially in the direction of fluid flow through the entire device (along the axis X-X', see Figures 4A-4C ).

[0070] In some configurations, the provision of the diffuser guide vane cascade 4 may be omitted.

[0071] The device comprises a gas-tight housing 6 (also referred to as a gas housing or pressure housing) in which an internal passage 7 is established in the form of a pipe or conduit extending between at least one inlet 8 and at least one outlet 9. The inner surface of the housing 6 faces the conduit 7. In some configurations, the conduit 7 is defined by the inner surface of the housing. The shape of the conduit / duct 7 varies depending on the device configuration.

[0072] In this disclosure, the gas housing 6 is generally referred to as the device housing. In practice, the device 100 may also be enclosed in a separate housing (see Figure 4C In the housing 14 shown.

[0073] The duct 7 formed in the housing is configured to substantially completely surround the periphery of the rotor on which a plurality of working blades, ie, fixed guide vanes and a diffuser are mounted.

[0074] In the device 100, the arrangement of fixed and working components (e.g., blade rows 2, 3, and 4) in the internal channel (duct 7) within the housing is such that one or more vaneless portions 7A (so-called vaneless spaces) are created between the outlet of the diffuser 4 (configured as a row of fixed diffuser vanes in some cases) arranged downstream of the rotor blades and the inlet of the fixed guide vane row 2 arranged upstream of the rotor blades.

[0075] The device 100 is configured with a plurality of basic stages, which are also referred to as working (process) stages. Each working stage is formed by a row of fixed guide vanes 2 ("stator"), a row of rotor blades 3 ("rotor") and a diffuser 4 ("diffuser") arranged in sequence, which together form a stator-rotor-diffuser stage sequence. The "diffuser" component in the sequence can be formed by a row of diffuser vanes, a vaneless diffuser or a portion of a vaneless space arranged behind the rotor blades. Single-stage or multi-stage configurations including 2-30 rows of rotor blades mounted on a rotor shaft can be envisioned. Some exemplary multi-stage configurations include 10 to 20 rows of rotor blades. In a multi-stage configuration, each stage can be driven by the same or different (e.g., engaged) rotor shafts.

[0076] exist Figure 4A-4C In the process, the working stages are represented by Roman numerals (ix; i-vii). The total number of stages is determined by the process load, the required temperature and / or pressure levels, and other process-related parameters.

[0077] The function of the basic stage is to regulate an energy conversion cycle during which the mechanical energy of the rotor shaft is converted into kinetic energy and further into the internal energy of the fluid, with the subsequent increase in the temperature of the fluid. That is, although the rotor is configured to transfer mechanical energy to the process fluid, the diffuser with or without guide vanes located downstream of the rotor is also configured to convert the mechanical energy (kinetic energy) of the process fluid into the internal energy of the process fluid. In the diffuser area, the high-speed fluid flow from the rotor is diffused with a significant entropy increase, whereby the fluid flow dissipates kinetic energy into the internal energy of the fluid substance, thereby providing thermal energy to the fluid.

[0078] During the energy conversion cycle, the fixed guide vane row 2 arranged upstream of the rotor blades 3 prepares the required flow conditions at the inlet of the rotating blade row (blade cascade). In said rotor blade row, the mechanical energy of the shaft and the rotating blades is transferred to the fluid flow. In at least a portion of each rotor blade row 3, the fluid flow is able to reach supersonic flow conditions.

[0079] The diffuser 4 arranged downstream of the rotor blades 3 converts the mechanical energy of the fluid into its thermal energy (heat). The fluid flow leaves the rotor blades 3 and enters the diffuser at supersonic speed. If the flow upstream of the diffuser is supersonic, the kinetic energy of the fluid flow is converted into the internal energy of the fluid through a multiple impact and viscous mixing and dissipation system. The flow dissipates its kinetic energy as the internal energy of the fluid flow propagating through the reactor (along the pipeline 7), thereby adding a certain amount of thermal energy to the fluid. The increase in the internal energy of the fluid causes the temperature of the fluid to rise.

[0080] exist Figure 4A In the configuration 100A shown, the device is generally configured as a substantially tubular axial flow turbine. The device 100A includes an elongated rotor 1 extending along a horizontal axis XX'. A plurality of rotor blades are arranged in a number of continuous rows along a rotor hub 3A to form a rotor blade cascade 3. The rotor 1 is enclosed in a housing 6, the inner surface of which is provided with a first fixed guide vane cascade 2 and a second fixed guide vane cascade 4, respectively, which are arranged so that the blades / vanes of the rotor and stator cascades 2, 3 and 4 are alternately arranged along the rotor 1 (along the axis XX') in the longitudinal direction. The rows of fixed guide vanes 2, 4 can be arranged on opposite sides of the housing (inner) surface facing the pipeline. The i-vii working stages are established, each of which is formed by a rotor blade cascade 3 and adjacent pairs of stator guide vanes 2, 4. The pipeline section 7A without blades / vanes is arranged between subsequent stages.

[0081] The housing 6 may be tapered, or it may have a substantially constant cross-section along its entire length (not shown).

[0082] exist Figure 4BIn the illustrated configuration 100B, the apparatus 100 is configured as a radial flow turbine, which generally follows the design of a centrifugal compressor or centrifugal pump. The term "centrifugal" means that the fluid flow within the device is radial; therefore, the apparatus 100B is referred to as a "radial flow apparatus". The apparatus embodied in 100B includes a plurality of working stages (i-vii), each of which can be represented by a fixed guide vane cascade 2, a rotor blade cascade 3, and a diffuser 4. The diffuser is mounted in a substantially U-shaped duct which is part of a conduit 7 and is followed by a vaneless portion 7A. The diffuser can be formed with or without diffuser vanes. In some configurations, a vaneless U-shaped duct located downstream of the rotor blade cascade can be employed to form a diffuser region (see stage v) by means of its three-dimensional shape, in which the mechanical energy imparted to the process fluid by the rotor is converted into heat. In Figure 4B , a diffuser 4 with guide vanes is shown for stages ii and iii; however, for example, a row of diffuser guide vanes may be installed downstream of each rotor blade cascade 3 (stages i-vii).

[0083] In addition to a multi-stage configuration 100A, 100B comprising several working stages arranged one after the other along the rotor axis, the device 100 may also comprise several stages arranged in a regenerative multi-stage configuration, such as Figure 4C shown.

[0084] Figure 4C At illustration (1) a configuration of an apparatus 100C is shown having two inlets 8 (8A, 8B) and two outlets 9 (9A, the second outlet not shown); other configurations are contemplated where appropriate.

[0085] The device 100 indicated at 100C is provided with a housing 6 which is substantially annular in shape ("donut" shape) in a three-dimensional configuration, whereby the rotor system (1, 3A, 3) with the associated bearing assembly (not shown) can be considered to fill an aperture defining an opening in the central portion of the annulus. In its meridional section, the housing 6 is substantially annular.

[0086] In the device 100C, the stationary guide vane cascades 2 , 4 are arranged as substantially annular components on both sides of the rotor blade cascade 3 .

[0087] The device in configuration 100C further comprises a flow shaping device (flow guiding device) 5, which is arranged in the gas housing and is configured as an internal fixed annular structure for establishing a substantially annular conduit in the housing 6. The flow shaping device 5 may be provided as an annular substantially hollow structure, such as a ring.

[0088] In configuration 100C, the internal passage is defined by the volume created between the gas housing 6 (outer "donut") and the internal flow shaping device 5 (inner "donut"). This internal passage (duct 7) formed between the inner surface of the gas housing 6 and the outer surface of the flow shaping device 5 thus takes a substantially annular shape with a substantially annular meridional cross section.

[0089] In the housing 6 , the blade rows 2 , 3 , 4 adjoin one another such that the vaneless section 7A of the duct 7 is located between the outlet of the fixed diffuser blade row 4 and the inlet of the fixed guide vane row 2 .

[0090] As described above, the working stage is formed with three rows of blades (2, 3, 4). In configuration 100C, the fluid leaving the outlet of the diffuser guide vane row 4 of one stage (e.g., the i-th stage) flows along a spiral (spiral annular) path in the duct 7 / its vaneless portion 7A and enters a row of fixed guide vanes 2 of the next stage (ii-th stage). The fluid passes through the successive blade rows 2, 3, 4 (ii-th stage), leaves the diffuser 4 (ii-th stage), and continues to flow to the subsequent iii-x stages until the fluid reaches the outlet 9, 9A (see Figures (2) and (3); wherein Figure (3) shows all the ix-th stages drawn in the same plane). The direction of the fluid is indicated by an arrow.

[0091] In a VCM production device, at least two rotating devices can be connected in parallel and / or in series. The connection between the rotating devices 100 can be a mechanical connection and / or a functional connection. Functional connections (such as connections achieved in terms of achievable heat input) can be established when at least two separate, physically integrated or non-integrated independent equipment units are associated. In the latter case, the association between at least two rotating devices can be established by several auxiliary devices (not shown). In some configurations, at least two rotating devices can be at least functionally connected by their rotor shafts, thereby mirroring each other. Rotating devices connected in arrays and / or sequences can have different types of drive engines, for example, a motor-driven reactor can be combined with a reactor driven by a steam turbine, a gas turbine and / or a gas engine.

[0092] The method disclosed herein also includes conducting a certain amount of input energy into at least one rotating device 100. In an embodiment, the input energy includes electrical energy. In the present disclosure, the amount of electrical input energy is defined in terms of electrical power, that is, as the rate of energy transfer per unit time (measured in watts). By adjusting the amount of input energy (e.g., electrical energy) conducted into at least one rotating device, the amount of thermal energy added to the flow of fluid medium propagating through the rotating device can be adjusted.

[0093] The amount of electrical energy conducted as input energy into at least one rotating device is in the range of about 5% to about 100%. In some cases, the amount of electrical energy used as input energy is in the range of about 50% to about 100%. The amount of electrical energy can be any of the following values: 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% and 100% (from the total energy input), or any intermediate value falling between the above points.

[0094] The rotating device may be supplied with electrical power (defined as the rate of energy transfer per unit time) by supplying an electric current to an electric motor used to propel a rotating shaft of the device. The rotating device may be supplied with electrical power from one or more external sources (associated with the rotating device 100 and / or the VCM production device). Additionally or alternatively, electrical energy may be generated internally within the VCM production device and / or within an associated industrial system (e.g., a factory or plant) in which the device is incorporated.

[0095] One or more external sources include various support facilities that provide sustainable energy production. Therefore, electricity can be supplied from a power generation system that utilizes at least one renewable energy source or a combination of power generation systems that utilize different renewable energy sources. The external source of renewable energy can be solar energy, wind energy and / or hydropower. Therefore, electricity can be received into the process from at least one of the following devices: a photovoltaic power generation system, a wind power generation system, and a hydropower generation system. In some exemplary instances, a nuclear power plant can be used as an external power source. Nuclear power plants are generally considered to be zero-emission. The term "nuclear power plant" should be interpreted as using traditional nuclear energy and, additionally or alternatively, also using fusion energy.

[0096] Electricity can be provided from a power station that uses a turbine as a kinetic energy source to drive a generator. In some cases, the electricity for driving the at least one device 100 can be provided from at least one gas turbine (GT), which is, for example, configured as a separate device, or is arranged in a cogeneration facility and / or a combined cycle power generation facility. Therefore, electricity can be provided from at least one of the following devices: a combined cycle power generation facility, such as a combined cycle gas turbine power plant (CCGT), and / or a cogeneration facility configured to generate electricity by combining heat and power (CHP) with heat recovery. In some examples, a CHP power plant can be a biomass-burning power plant to increase the share of renewable energy in the process. Additionally or alternatively, the supply of electricity can be realized from, for example, a spark-ignition engine (e.g., a gas engine) and / or, for example, a compression engine (e.g., a diesel engine), which are optionally provided as part of an engine power plant. Further, any conventional power plant configured to generate electricity from fossil raw materials such as coal, oil, natural gas, gasoline, etc. (usually regulated by a steam turbine) can be used to generate electricity as input energy for the rotating device 100. Furthermore, hydrogen can be used as a source of renewable energy, for example by converting it back into electricity using fuel cells.

[0097] Any combination of the above-mentioned power sources implemented as external and internal sources is contemplated.

[0098] Conducting input energy (including electricity) into the drive system of the rotating equipment may also be accompanied by conducting mechanical shaft power from a power turbine into it, for example, optionally using heat energy generated elsewhere. Shaft power is defined as the mechanical power transferred from one rotating element to another, and is calculated as the sum of the torque and the rotational speed of the shaft. Mechanical power is defined as the amount of work or energy per unit time (in Watts).

[0099] For example, in practice, the shaft power from the electric motor and the power turbine may be split so that either one can provide all or part of the shaft power.

[0100] Please refer again Figure 1A and 1B , which shows an embodiment involving the use of a rotating device 100 to directly heat a process fluid.

[0101] The method comprises directly thermally cracking an EDC-containing feed in a rotating device 100 (100A, 100B, 100C). The EDC-containing feed is introduced into the rotating device 100 through one or more inlets 8, 8A, 8B (see Figures 4A-4C) enters the device 100, and the EDC-containing process fluid stream flows along the conduit 7 to one or more outlets 9, 9A, 9B according to a flow path specific to each type of device. In this way, the amount of thermal energy required to heat the EDC-containing process fluid stream to a temperature at which the cracking reaction occurs is transferred and thereby directly added to the EDC-containing process fluid flowing through the device.

[0102] The amount of thermal energy required to heat the EDC-containing process fluid stream to a temperature at which the cracking reaction occurs is generated in the rotating device by means of a series of energy conversions that occur when the fluid medium flow propagating in the pipeline between the inlet and the outlet passes successively through the fixed guide vanes, the rotor blades and the fixed diffuser, respectively.

[0103] exist Figure 1A and 1B In the configuration shown, the rotating apparatus 100 acts as a cracking reactor (cracking furnace).

[0104] The fluid stream propagating through the apparatus 100 passes through a plurality of working stages in sequence, and, with each pass, the temperature of the process fluid increases by a certain value. More precisely, the temperature increases as the process fluid stream leaves the rotor blades and passes through the diffuser and the vaneless space. The increased temperature promotes the thermal degradation of the feedstock material and its conversion into the desired product. The amount of thermal energy added to the fluid is sufficient to initiate chemical degradation reactions, in particular reactions that result in the breaking of carbon-hydrogen (CH) and carbon-chlorine (C-Cl) bonds. As a result, the ethylene dichloride molecules present in the fluid stream decompose, thereby producing vinyl chloride (monomer) having a lower molecular weight.

[0105] In the method involving direct heating of reactants in the device 100, the EDC feed preferably enters the device 100 in gaseous form together with possible co-reactants (e.g., chlorine or chlorinated hydrocarbons). The gaseous feed passes through a series of stator-rotor-diffuser stages, wherein the propagation through each such stage results in a portion of the heat energy being added to the process fluid (gas), because the kinetic energy input into the flow by the rotation of the rotor shaft / blades is dissipated into the heat energy of the fluid via the shock wave system. The temperature of the process fluid increases with each subsequent stage. In other words, the temperature of the process fluid is gradually increased until the EDC cracking temperature value is reached, and EDC decomposition begins to occur. As the temperature continues to rise, the EDC cracking reaction rate increases, and the endothermic reaction begins to reduce the temperature of the reactants between the various stages. The gaseous reactants pass through several stages, thereby achieving the desired EDC feed conversion rate. After being discharged from the device 100, the high-temperature product stream undergoes rapid cooling (quenching) to prevent the reaction from proceeding further. The cooled product stream is directed to a separation section (not shown) from a cooling device (e.g., a quench tower, a transmission line exchanger / TLE, etc.).

[0106] Prior to entering the apparatus 100, the EDC feed may be preheated to a predetermined temperature (inlet temperature).

[0107] Because the heat generation in the equipment 100 as cracking reactor (cracking furnace) is to be in process fluid by the shock wave dissipation mechanism of kinetic energy conversion into thermal energy inherently occurs, therefore do not need to transfer heat in process fluid by reactor surface (that is, by the metal surface of coil) as carried out in the conventional cracking furnace equipped with fired heater.Therefore, can realize the extremely fast heating of the fluid medium propagated by this equipment.The residence time that fluid spends by working stage (stator-rotor-diffuser sequence) is a fraction of a second, for example about 0.1-10 millisecond (0.0001-0.01 second).This causes the heating rate to be several orders of magnitude faster than conventional fired heater, and in conventional fired heater, heat is to be transferred by the wall of coil by conduction and convection mode.

[0108] This lack of external heating results in lower reactor surface temperatures (compared to conventional EDC cracking furnaces) since no external heat needs to be transferred to the reactants. Due to the lower surface temperatures, less coke and other foulants are formed; therefore, the operating time between decoking outages is extended.

[0109] With the above advantages, the temperature of the process fluid can be increased to a temperature higher than that of a typical EDC cracking process (500-550°C).

[0110] In general, parameters related to the process stream, such as flow rate and temperature, can be adjusted as needed. When the device 100 is used as a cracking reactor, the temperature increase can be in the range of about 10°C to about 120°C in one stage. Therefore, in a "single pass" configuration, the fluid medium flow propagating through the device 100 can be heated to about 1000°C in a very short time (in a 10-stage device, the temperature rises by 100°C per stage). This increases the rate of the EDC cracking reaction, significantly reduces the reaction time, and thus allows the same single-pass conversion to be achieved in a much smaller reactor size (compared to a conventional cracking furnace).

[0111] Alternatively, in a similar sized reactor, adjusting the operating temperature to a higher level (ie, above "conventional" EDC cracking temperature) allows for increased per pass conversion.

[0112] Figure 1A A VCM production method and associated production apparatus suitable for cracking EDC to produce VCM in a single device 100 is shown at 101, 101A. By optimizing the reaction temperature to an appropriate level so that the pyrolysis is carried out at a rate that can achieve EDC conversion within a single reactor device, it is possible to implement Figure 1A Configuration of the device 100 ( Figure 1A) may be suitable for immediate heating of the EDC-containing feed, or, alternatively, the pyrolysis temperature may be reached in several working stages (as described below).

[0113] The temperature of the fluid medium propagating through the working stages of the apparatus 100 may be optimized as desired. In particular, the temperature rise of each stage may be optimized to promote thermal decomposition of EDCs in all stages or selected stages. Figure 1B A configuration is shown in detail where several working stages (i-iv) are assigned the function of (pre-)heating the EDC feed to a predetermined temperature. Figure 1B The configuration is shown in which the process stream reaches a temperature at which the feed starts to actively decompose after passing through three or four so-called (pre)heating stages. In practice, the decomposition reaction may already occur after the process fluid has passed through the first working stage. The working stage in the pipeline zone where the actual cracking reaction occurs is called a reaction stage.

[0114] Figure 1B A VCM production method and related production apparatus suitable for cracking EDC in a single device 100 is further shown at 101, 101B, and the device 100 includes means (F1-F3) for extending the residence time within the reaction stage. Figure 1B The equipment 100 of the present invention comprises a device for extracting process fluid from the equipment and for sucking other fluid into the equipment. Other fluid can be any one of feed gas, circulating gas, make-up gas (so-called replacement / make-up gas), process fluid (process fluid such as transferred from parallel equipment), any one of the dilution media for cooling / heating. In some cases, any one of the units F1, F2 and F3 in the equipment can be configured to, for example, a heat exchanger, to cool the process fluid. The cooling of the process in the reaction stage can be used for further optimizing the reaction yield.

[0115] Figure 2B At 101 , 101C, a VCM production method and related production apparatus according to another embodiment are shown. Figure 2B The configuration involves indirectly heating the process fluid using a rotating device 100, 100-1. In this method, the cracking of EDC can be carried out in any pyrolysis furnace 200 suitable for this purpose, including any type of conventional EDC cracking unit. The furnace 200 can be configured as a cracking furnace suitable for thermal cracking of a feed containing ethylene dichloride.

[0116] The amount of heat energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs is generated using a rotating device 100, 100-1, and the heat energy is transferred to the process fluid containing EDC, wherein a heated fluid medium is generated by adding the amount of heat energy to a fluid medium propagating through the rotating device. The heated fluid medium generated in the device 100, 100-1 can be an inert gas, such as air, nitrogen or steam, or any other substance suitable for the purpose of the present invention. The heated fluid medium is further used as a carrier to transfer heat energy to the pyrolysis furnace 200, and the process fluid stream containing EDC flowing through the pyrolysis furnace is heated to a temperature at which a cracking reaction occurs.

[0117] The heated fluid medium used as a thermal energy carrier may be any substance selected from the group consisting of air, nitrogen, steam, flue gas exhausted from a pyrolysis furnace, and any combination thereof.

[0118] By using the apparatus 100, 100-1 to indirectly heat the process fluid containing EDC, the performance of a conventional EDC cracking furnace can be improved. Figure 2A The working principle of the conventional furnace shown is that natural gas burns in the furnace's firebox, the flame and the hot exhaust gases heat the reactor coils, inside which the reactants of EDC cracking flow. After transferring part of their heat to the reactants, the still hot exhaust gases are discharged to the atmosphere. Typically, the temperature of the flue gases is above 120°C to prevent water condensation, which, together with the acidic substances in the exhaust gases, would create a corrosive environment.

[0119] Figure 2B It shows how to use the apparatus 100, 100-1 to replace the flame heating in the furnace. The fluid medium (eg inert gas) is heated to a predetermined temperature in the apparatus 100-1, whereby the heated fluid medium is used to provide thermal energy to the EDC-containing process fluid flowing through the radiant coils of the furnace 200.

[0120] When using the hot effluent discharged from the device 100, 100-1 as the heating medium, no carbon dioxide emissions are generated because no incineration occurs. The flue gas generated during the cracking process in the furnace 200 can be at least partially recovered to be used in the device 101 (101C, Figure 2B ) is used as a heating medium in the device 100, 100-1 (for example, optionally mixed with an inert gas). As a result, the amount of heat loss in the flue gas discharged into the atmosphere can be significantly reduced.

[0121] The use of the apparatus 100 as a heater in conjunction with a conventional EDC pyrolysis furnace 200 allows for reduced emissions and improved energy efficiency of existing furnaces. Installation of the apparatus 100 into an existing EDC cracking furnace facility can be achieved with very low capital requirements, since most of the process equipment does not need to be replaced. The existing furnace 200, for example, can be equipped with an appropriate piping arrangement around the reactor coils to enable heat to be transferred from the fluid (e.g., inert gas) being heated in the apparatus 100, 100-1 to the EDC-containing process fluid flowing through the coils.

[0122] Another benefit of indirect heating is improved temperature control. In conventional flame heaters, the temperature of the flame is very high, ranging from 1800-2200°C, depending on the fuel and air preheating. This increases the temperature of the furnace tubes, especially in the lower combustion section of the furnace, and leads to accelerated coking. With the apparatus 100, 100-1, the temperature of the cracking furnace 200 can be kept at a lower level. In addition, a more uniform heat distribution throughout the furnace can be achieved. This will significantly reduce the coking rate, respectively, and allow the EDC cracking reaction to be pushed to a typical single-pass conversion rate range of more than 60%, because coking will no longer be a limiting factor.

[0123] Figure 3 Another embodiment of the VCM production method and related production device is shown at 101 and 101D. Figure 3 In a configuration of at least two rotating devices 100 are connected to form a system, wherein the first device 100-1 is assigned a heater function to (pre)heat the process fluid containing EDC (see Figure 2B ), and the second device 100-2 arranged downstream of the first device is given the function of a thermal cracking furnace. The device 100-2 is configured to directly heat the process fluid containing EDC, and it can be implemented as a reference Figure 1A and 1B Any of the devices described.

[0124] If it is necessary to limit the reaction temperature (e.g. for selectivity reasons), then Figure 3 The device 100 ( Figure 1B ) involves at least two devices 100-1, 100-2 Figure 3The configuration enables separation of the (pre)heating and reaction processes. In the arrangement 101D, the (pre)heating and pyrolysis of the process fluid are performed in different devices 100-1, 100-2, respectively, wherein the first device in the sequence can be used for (pre)heating the feedstock, and the second device in the sequence can be used for EDC cracking. The production device 101D can also include a device for extracting fluid from the devices 100-1, 100-2 and sucking fluid into the devices 100-1, 100-2 (see reference 101D). Figure 1B Thus, any one of the devices 100-1, 100-2 may include a Figure 1B Arrangement described (F1-F3).

[0125] For all configurations involving direct heating of the process fluid in the apparatus 100 ( Figure 1A , 1B and Figure 3 ), the reaction devices 100 and 100-2 can be designed to improve selectivity. Achieving a high reaction temperature in the device 100 in a short time is beneficial to overcome low conversion.

[0126] The present invention also relates to a method for producing polyvinyl chloride (PVC), which is provided by a polymerization process of vinyl chloride monomer (VCM) obtained by the above-mentioned embodiment of the method for producing VCM. The polymerization of VCM can be carried out in any facility suitable for this purpose.

[0127] In one aspect, the present invention relates to a VCM production plant for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking.

[0128] In an embodiment, the VCM production device includes at least one rotating device 100, 100A, 100B, 100C, which is configured to generate the amount of thermal energy required to heat the process fluid stream containing EDC to a temperature at which a cracking reaction occurs, and transfer the amount of thermal energy to the process fluid containing EDC. The at least one rotating device includes: a rotor having a plurality of rotor blades, the plurality of rotor blades being arranged in at least one row on the circumference of a rotor hub mounted on a rotor shaft; a plurality of fixed guide vanes arranged in one or more rows upstream of the rotor blades; and a fixed diffuser arranged downstream of the rotor blades, wherein the rotor and the fixed guide vanes are enclosed in a pipe formed between at least one inlet and at least one outlet in the rotating device. Therefore, the at least one rotating device is configured to generate the amount of thermal energy by means of a series of energy conversions that occur when a fluid medium flow propagating in a pipe between one or more inlets and one or more outlets passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively, one after another.

[0129] The VCM production apparatus may be configured to have at least two rotating devices connected in parallel and / or in series.

[0130] In an embodiment, at least one rotating device in the VCM production unit is assigned the function of a thermal cracking furnace (see Figure 1A , Figure 1B and Figure 3 ).

[0131] In another embodiment, in the VCM production unit, the at least one rotating device is assigned a (pre-)heater function and is configured to generate a heated fluid medium by adding the amount of thermal energy to the fluid medium propagating through the rotating device and to transfer the amount of thermal energy to a pyrolysis furnace (e.g. a tubular cracking furnace) configured to perform thermal cracking of EDC to produce VCM (see Figure 2B and Figure 3 ).

[0132] The VCM production unit may be configured to include at least two rotating devices connected in a system, wherein the first device is assigned a preheater function for (pre)heating the EDC-containing process fluid, and the second device arranged downstream of the first device is assigned a thermal cracking furnace function (see Figure 3 ).

[0133] In another aspect, the invention relates to the use of a rotary device 100, 100A, 100B, 100C in the production of vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking. Thus, the device comprises a rotor having a plurality of rotor blades arranged in at least one row on the circumference of a rotor hub mounted on a rotor shaft; a plurality of fixed guide vanes arranged in one or more rows upstream of the rotor blades; and a diffuser arranged downstream of the rotor blades, wherein the rotor, the plurality of fixed guide vanes and the diffuser are enclosed in a duct formed in the rotary device between at least one inlet and at least one outlet. The use is to generate, in the rotary device, the amount of thermal energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs, and further transfer the thermal energy to the process fluid containing EDC, by means of a series of energy conversions occurring when a fluid medium flow propagating in a duct between one or more inlets and one or more outlets passes successively through the fixed guide vanes, the rotor blades and the fixed diffuser, respectively.

[0134] Embodiments of the present invention are further explained in the following non-limiting examples.

[0135] Example

[0136] Direct heating

[0137] The embodiments herein relate to a configuration suitable for direct heating of an EDC feed ( Figure 1A , Figure 1B , Figure 3 ). The simulation data obtained in Examples 1-5 are summarized in Table 1. To simulate the performance of a conventional EDC cracking furnace (Comparative Example 1) and a rotary device 100 (Examples 2-5), AspenPlus V12.1 process simulation software (AspenTech) was used.

[0138] Table 1. Simulation data for Examples 1-5 using a conventional EDC cracking furnace (Comparative Example 1) and a rotary apparatus 100 (Examples 2-5) to crack EDC.

[0139]

[0140]

[0141] Although pyrolysis involves hundreds of reactions with molecular compounds and free radicals, a simplified computational model was used to simulate the pyrolysis kinetic mechanism (Reaction 1), assuming that the pyrolysis reactions occurring in the EDC cracking furnace involve the following components: EDC, VCM, hydrogen chloride (HCl), and byproducts represented by acetylene (C2H2). Therefore, in addition to simulating the kinetics of the main reaction (Reaction 2a), the kinetics of the side reaction (Reaction 2b) was also simulated, which involves the formation of acetylene as a model byproduct that contributes to coke formation.

[0142] Reaction 1. EDC → VCM → byproduct

[0143] Reaction 2a. EDC → VCM + hydrochloric acid

[0144] Reaction 2b. VCM → acetylene + hydrochloric acid

[0145] Example 1 is a comparative example, in which the EDC cracking process was simulated in a conventional tube furnace. For Example 1, the method described in Li et al. (2013) was used. [1] The data of the cracking furnace system and its simplified EDC cracking kinetic mechanism discussed in are presented. Based on the literature sources mentioned, the simulated furnace has two rows of reactor coils (each row includes 20 straight tubes and 19 elbows), an inlet pipe diameter of about 0.1 m, an EDC feed rate of 42 t / h, an inlet temperature of about 260°C and a pressure of about 2400 kPa. With these parameters, the residence time of the process fluid through the coils is 26-27 seconds. It is assumed that the adiabatic volume (the last part of the reactor before quenching) is equal in all cases: the residence time in the adiabatic volume is about 0.06 seconds. The temperature curve of the entire reactor defines the extent of the reaction. The temperature curve and mass fraction curve of Comparative Example 1 are shown in Figure 5A and5B middle.

[0146] Figure 5A The temperature profile shown is typical of a conventional EDC cracking furnace. The process temperature rises steadily from 260°C (feed gas temperature) until about 400°C, when endothermic reactions begin to occur; from this point on, the rate of temperature rise slows and levels off. The reaction rate in the first part of the reactor is low (see Figure 5B As the EDC-containing process fluid propagates toward the reactor outlet, the rate of the chemical reaction increases to the point where direct quenching is required.

[0147] For Figure 4A The devices 100, 100A shown were used to simulate Examples 2-5.

[0148] Example 2 was modeled to show that the average EDC cracking range (T 最大 =520°C) can successfully replace the conventional EDC cracking furnace. The temperature curve and mass fraction curve of Example 2 are shown in Fig. 6A and 6B middle.

[0149] Example 2 was simulated with the following four (4) working stages implemented in configuration 100A: four stator-rotor-diffuser sequences 2, 3, 4, each of which heats the gaseous process fluid containing EDC by about 120°C (delta T (ΔT) = 120°C). The first two stages are assumed to be located at the beginning of the reactor and represent so-called (pre)heating stages. These stages can be located in the device 100 (100A) configured as a thermal cracking furnace (in Figure 1A , 1B ), or, these stages may be located in a device 100-1 configured as a (pre-)heater. In the present simulation, it is assumed that the last two stages represent so-called reaction stages.

[0150] In a simulation involving a single reaction device 100 (see Figure 1A , 1B ), within 1-5 milliseconds, the reactor is heated to about 510°C (in the first two preheating stages). At this point, as the EDC decomposes, the temperature of the gas stream decreases due to the endothermic reaction between stages (the process fluid containing EDC passes through the vaneless portion of pipe 7, 7A). A residence time of about 6 seconds is allowed until the process fluid enters the third working stage and is reheated to about 520°C. Thereafter, the process temperature is allowed to decrease again, and, in the final fourth working stage, the process fluid is reheated to about 520°C. Due to the endothermic reaction occurring in the process fluid, the temperature of the process fluid at the reactor outlet may be lower (compared to conventional reactors) than in conventional reactors. Figure 5A and 6AIn various configurations (100A, 100B or 100C), the apparatus 100 can be configured so that the adiabatic volume within the reactor (the portion of the conduit 7 between the last working stage and the reactor outlet) is optimized to meet the requirements of the process. The optimization can be performed by modifying the three-dimensional expansion within the apparatus containing the adiabatic volume (e.g., shrinking or expanding).

[0151] The acetylene production rate in the apparatus 100 (at its outlet) is significantly lower than the acetylene production rate in conventional cracking furnaces. This results in reduced coke formation in the reaction zone of the apparatus 100 and at its outlet.

[0152] In general, for the apparatus 100, the residence time required for the cracking reaction to occur is shorter because a higher reaction temperature (T 最大 ).

[0153] Examples 3 and 4 are simulations for the device 100 operating at a temperature that deviates from the average EDC cracking temperature (about 520° C., see Example 2). Example 3 is designed for an operating temperature below the average EDC cracking temperature, while Example 4 is designed for an operating temperature above the average EDC cracking temperature. On the other hand, compared to the conventional cracking furnace of Example 1, Example 3 is designed for an operating temperature similar to the maximum temperature of the conventional EDC cracking furnace (T 最大 =480°C) of the device 100; while Example 4 is for the maximum temperature (T 最大 =600°C). The heat input for each stage is the same as before: ΔT = 120°C. However, the delta T parameter can be optimized according to the specific situation. The temperature curves and mass fraction curves of Examples 3 and 4 are respectively presented in Fig. 7A , 8A and 7B, 8B.

[0154] Both Examples 3 and 4 were run to higher conversions than the conventional cracking furnace (Example 1). Reducing the operating temperature (Example 3) extends the residence time of the process fluid in the reactor beyond the residence time normally required for the pyrolysis reaction to occur, thus Figure 1B It appears to be beneficial to carry out the process of Example 3 in the apparatus 100 of the configuration shown. Increasing the operating temperature (Example 4) reduces the required residence time to one-tenth that of a conventional cracking furnace.

[0155] Another significant difference between Example 3 and Example 4 is selectivity. The simulated kinetics show that lower temperatures and longer residence times (Example 3) improve process selectivity compared to the conventional cracking furnace of Example 1. This opens up the possibility of running the cracking process to higher conversions and reduced coke formation.

[0156] Most by-products (e.g., acetylene) are produced at the end of the cracking process. In the kinetic model used here, the acetylene formation reaction is driven by the increase in VCM concentration. High reaction temperature also promotes the formation of acetylene. Therefore, the combination of high reaction temperature and high conversion is an undesirable situation.

[0157] The purpose of Example 5 is to verify whether rapid heating to high temperature (reaction temperature at which EDC pyrolysis occurs) at the beginning of the reactor 100 has a positive effect on selectivity. Example 5 was simulated with four (4) working stages, where each stage was defined as a stator-rotor-diffuser sequence 2, 3, 4. In contrast to Example 2, in the present Example 5, all four stages are located in the first part of the reactor, directly at the reactor inlet, in order to instantly heat the feed gas to an extremely high temperature of almost 730°C. The temperature distribution curve and mass fraction curve of Example 5 are shown in Figures 1 and 2, respectively. Fig.9A and 9B middle.

[0158] In Example 5, the reaction started with EDC decomposition at a high rate. A conversion of about 13% was achieved in about 40 milliseconds; and a conversion of about 50% was achieved in one second. The process fluid reached the adiabatic volume at the end of the reactor in a period of only 5.3 seconds (residence time = 5.3 seconds). During this period, EDC conversion reached 60%. However, although we initially assumed that acetylene formation could be controlled by this transient heating step (since process fluid temperature decreases with increasing VCM concentration), the system exhibited lower selectivity for VCM and higher acetylene concentrations.

[0159] Heat loss

[0160] According to literature sources (see, for example, Li et al. [1] ), conventional cracking uses about 1000kg / h of fuel gas. Based on the heat of combustion, the total energy output of the furnace can be estimated to be 13MW. Simulations estimate that a conventional EDC cracking furnace requires about 8.3MW of energy to heat the process fluid where the cracking reaction occurs, which results in a flue gas loss of about 4.7MW. According to the above reference, the flue gas temperature at the furnace outlet (which accounts for most of the heat loss) is 900K, and using the estimated heat capacity and the reduction in flue gas temperature back to conditions close to the atmosphere results in essentially the same energy loss value. Therefore, the heat input to the conventional EDC cracking furnace is lost by about 36%.

[0161] On the other hand, when the rotary device 100 is used to directly heat the raw material (see Figure 1A , Figure 1B , Figure 3), heat losses are negligible and are primarily due to motor output and drive efficiency. For example, the efficiency of the motor-driven rotating device 100 is estimated to be approximately 94%. Thus, its energy losses are approximately six (6) times less than those occurring in conventional EDC cracking furnaces.

[0162] The heat input and loss of Examples 1-5 are shown in Table 2.

[0163] Table 2. Heat input and loss for Examples 1-5.

[0164]

[0165]

[0166] The higher heat input in Example 4 is due to the provision of an additional working stage. In Example 4, there is additional heat in the product gas that is not consumed by the endothermic reaction to provide higher conversion to further integrate (by recycling) into the feed heating. The difference in the values ​​representing the heat utilized in the reactor (MW) is related to the difference in outlet temperature and conversion.

[0167] Indirect heating

[0168] The following embodiment relates to a configuration suitable for indirect heating of EDC feed in a cracking furnace 200, wherein the device 100, 100-1 has a (pre)heater function ( Figure 2B By using the indirect heating of the rotating device 100, 100-1, the cracking reaction and the thermal decomposition temperature profile can be carried out as shown in Example 1, except that the coil temperature can be reduced and the coke formation is reduced accordingly. The local temperature difference in the cracking furnace will also be smaller.

[0169] A major advantage of the indirect heating method is energy saving. Since no flue gas is generated, the heating medium (i.e., heat transfer medium) can be recycled to the rotating device for reheating. Assuming a fairly high purge rate of 5%, the heat loss caused by the flue gas is 5% of the conventional EDC cracking furnace of 0.23MW. Additional losses occur in motor output and drive efficiency. Since the heat consumption in the cracking furnace (200) is about 8.3MW, and about 0.23MW is retained for flue gas losses, the rotating device 100, 100-1 must generate about 9.1MW of heat. The heat loss is estimated to be 0.54MW. Therefore, the total heat loss in the indirect heating method is about 0.79MW, which is slightly higher than one-tenth of the loss observed in a conventional EDC cracking furnace.

[0170] It is clear to a person skilled in the art that as technology advances, the basic idea of ​​the invention can be implemented and combined in various ways.The invention and its embodiments are therefore not limited to the examples described above, but they may generally vary within the scope of the appended claims.

[0171] References:

[0172] [1]Chaochun Li, Guihua Hu, Weimin Zhong, Hui Cheng, Wenli Du and Feng Qian, Comprehensive Simulation and Optimization of an Ethylene Dichloride CrackerBased on the One-Dimensional Lobo–Evans Method and Computational FluidDynamics, Ind.Eng.Chem.Res.2013,52,2,645-657.

Claims

1. A method (101, 101A, 101B, 101C) for producing vinyl chloride monomer (VCM), the method comprising: Thermal cracking of ethylene dichloride (EDC) to produce a gaseous product containing VCM, A rotating device (100) is used to generate heat energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs, and to transfer the heat energy to the process fluid containing EDC, wherein the rotating device (100) comprises: A rotor having a plurality of rotor blades (3) arranged in at least one row on the circumference of a rotor hub (3A) mounted on a rotor shaft (1); a plurality of fixed guide vanes (2) arranged in one or more rows upstream of the rotor blades; and a fixed diffuser (4) arranged downstream of the rotor blades, wherein the rotor, the fixed guide vanes and the diffuser are enclosed in a duct (7) formed between at least one inlet (8) and at least one outlet (9) in the rotating device, In the rotating device, the thermal energy is generated by means of a series of energy conversions that occur when the fluid medium flow propagating in the pipeline between one or more inlets and one or more outlets passes through the fixed guide vanes (2), the rotor blades (3) and the diffuser (4) respectively and successively.

2. The method (101, 101A, 101B) according to claim 1 comprises thermally cracking EDC in a rotating device (100), wherein a cracking reaction is induced in a process fluid containing EDC propagating through the rotating device by directly adding an amount of thermal energy required for the cracking reaction to occur to the process fluid stream containing EDC.

3. The method (101, 101C) according to claim 1, comprising thermally cracking EDC in a pyrolysis furnace (200) suitable for the purpose of thermal cracking EDC, the method further comprising: - in a rotating device (100), generating a heated fluid medium by adding thermal energy to the fluid medium propagating through the rotating device, and - Using the fluid medium as a carrier to transfer heat energy to the pyrolysis furnace (200) and to heat the EDC-containing process fluid stream flowing through the pyrolysis furnace to a temperature at which a cracking reaction occurs.

4. The method (101, 101C) according to claim 3, wherein the heated fluid medium used as a thermal energy carrier is any one of air, nitrogen, steam, flue gas exhausted from a pyrolysis furnace, and any combination thereof.

5. The method (101, 101C) according to any one of the preceding claims 3 or 4, wherein the pyrolysis furnace (200) is any cracking furnace suitable for thermal cracking of a feed containing ethylene dichloride.

6. The method (101, 101A, 101B, 101C) according to any of the preceding claims, comprises connecting at least two rotating devices (100) into a system, wherein a first device (100-1) is assigned a preheater function to (pre)heat a process fluid containing EDC, and a second device (100-2) arranged downstream of the first device is assigned a thermal cracking furnace function.

7. The method (101, 101A, 101B, 101C) of any one of the preceding claims, further comprising conducting input energy into at least one rotating device, wherein: The amount of thermal energy added to the flow of fluid medium propagating through the rotating device is regulated by adjusting the amount of the input energy conducted into the at least one rotating device.

8. The method (101, 101A, 101B, 101C) according to claim 7, wherein the input energy is electrical energy.

9. The method (101, 101A, 101B, 101C) of claim 8, wherein the amount of electrical energy conducted as input energy into the at least one rotating device (100) is in the range of approximately 5% to 100%.

10. The method (101, 101A, 101B, 101C) according to any one of claims 8 or 9, wherein: The electrical energy conducted as input energy into the at least one rotating device (100) can be obtained from renewable energy sources or a combination of different energy sources, optionally from renewable energy sources.

11. The method (101, 101A, 101B, 101C) according to any of the preceding claims, comprising adjusting the speed and / or pressure of the fluid medium flow propagating through the rotating device (100) to produce conditions under which, when the fluid medium flow leaves the at least one row of rotor blades at a supersonic speed and passes through the fixed diffuser (4), kinetic energy is added to the fluid medium flow by the rotating blades (3) of the rotor in an amount sufficient to increase the temperature of the fluid medium to a predetermined value, in which the flow decelerates and dissipates the kinetic energy as internal energy of the fluid medium, thereby adding the thermal energy to the fluid medium flow.

12. The method (101, 101A, 101B, 101C) according to claim 11, wherein thermal energy added to the fluid medium flow propagating through the rotating device (100) is generated by means of a shock wave system generated during the fluid medium flow propagating successively through the multiple rows of fixed guide vanes (2), the one row of rotor blades (3) and the fixed diffuser (4) in a controlled manner.

13. A method for producing polyvinyl chloride (PVC) by polymerizing VCM obtained using the method (101, 101A, 101B, 101C) according to any one of claims 1 to 12.

14. A VCM production device (101, 101A, 101B, 101C) for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking, the production device comprising: At least one rotating device (100) configured to generate heat energy required to heat a process fluid stream containing EDC to a temperature at which a cracking reaction occurs and to transfer the heat energy to the process fluid containing EDC, the at least one rotating device comprising: A rotor having a plurality of rotor blades (3) arranged in at least one row on the circumference of a rotor hub (3A) mounted on a rotor shaft (1); a plurality of fixed guide vanes (2) arranged in one or more rows upstream of the rotor blades; and a fixed diffuser (4) arranged downstream of the rotor blades, wherein the rotor and the fixed guide vanes are enclosed in a duct (7) formed between at least one inlet (8) and at least one outlet (9) in the rotating device, The at least one rotating device is configured to generate thermal energy by means of a series of energy conversions occurring when a fluid medium flow propagating in the duct between one or more inlets and one or more outlets passes through the fixed guide vanes (2), the rotor blades (4) and the diffuser (4) respectively and successively.

15. The VCM production plant (101, 101A, 101B) according to claim 14, wherein the at least one rotating device is endowed with a thermal cracking furnace function.

16. The VCM production device (101, 101C) according to claim 14, wherein the at least one rotating device is endowed with a (pre-)heater function and is configured to generate a heated fluid medium by adding thermal energy to the fluid medium propagating through the rotating device, and transfer the thermal energy to a pyrolysis furnace (200) configured to perform thermal cracking of EDC to produce VCM.

17. The VCM production device (101, 101C) according to claim 16, wherein the pyrolysis furnace (200) is a tubular cracking furnace.

18. The VCM production device (101, 101A, 101B, 101C) according to any one of claims 14 to 16, comprising at least two rotating devices connected in parallel and / or in series.

19. The VCM production unit (101, 101A, 101B, 101C) according to any one of claims 14 to 16 comprises at least two rotating devices connected into a system, wherein a first device (100-1) is assigned a preheater function to (pre)heat the EDC-containing process fluid, and a second device (100-2) arranged downstream of the first device is assigned a thermal cracking furnace function.

20. The VCM production apparatus (101, 101A, 101B, 101C) according to any one of claims 14-19, wherein the at least one rotating device is electrically driven.

21. A VCM production device (101, 101A, 101B, 101C) according to any one of claims 14 to 20, wherein the at least one rotating device (100) is configured to achieve fluid flow between the inlet (8) and the outlet (9) along a flow path established according to any one of the following trajectories: a substantially spiral trajectory formed in a substantially annular shell; a substantially spiral trajectory formed in a substantially tubular shell; and a flow path established by means of a fluid medium flow in the form of two spirals rolled into right-hand and left-hand vortex rings.

22. Use of a rotating device (100) for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) by thermal cracking, the rotating device comprising: A rotor having a plurality of rotor blades (3) arranged in at least one row on the circumference of a rotor hub (3A) mounted on a rotor shaft (1); a plurality of fixed guide vanes (2) arranged in one or more rows upstream of the rotor blades (3); and a diffuser (4) arranged downstream of the rotor blades (3), the rotor, the plurality of fixed guide vanes and the diffuser being enclosed in a duct (7) formed between at least one inlet (8) and at least one outlet (9) in the rotating device, In the rotating device (100), by means of a series of energy conversions occurring when the fluid medium flow propagating in the pipeline between one or more inlets (8) and one or more outlets (9) passes through the fixed guide vanes (2), the rotor blades (3) and the fixed diffuser (4) respectively, the thermal energy required for heating the process fluid flow containing EDC to the temperature at which the cracking reaction occurs is generated, and the thermal energy is further transferred to the process fluid containing EDC.

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