Production of vinyl chloride monomer

Abstract

A method for producing vinyl chloride monomer (VCM), the method comprising subjecting ethylene dichloride (EDC) to thermal cracking to produce a VCM-containing gaseous product, is provided. In this method, an amount of thermal energy required to heat an EDC-containing process fluid stream to a temperature at which a cracking reaction occurs is generated, and the thermal energy is transferred to the EDC-containing process fluid using a rotating device (100). Further provided is the use of a rotating device in a VCM production unit and in the production of vinyl chloride monomer (VCM) from EDC through thermal cracking.

Description

Technical Field

[0001] Broadly speaking, the present invention relates to the production of vinyl chloride monomer from ethylene dichloride. Specifically, the present invention relates to using a rotating device to convert ethylene dichloride into vinyl chloride monomer by thermal cracking.

Background Art

[0002] Vinyl chloride monomer (VCM) or chloroethane is one of the most important bulk chemicals. The main use of VCM is in the production of polyvinyl chloride (PVC). Here, VCM is used as a monomer to build blocks for PVC polymers. PVC is currently the second most abundant polymer in the world after polyethylene. The annual production volume of PVC is approximately 60 million tons worldwide. Approximately 96% of VCM is used for the production of PVC.

[0003] In the early 20th century, VCM was mainly produced from acetylene. By catalytically reacting acetylene with hydrochloric acid, VCM could be produced (see Equation 1). (1)C 2 H 2 + HCl → CH 2 =CHCl

[0004] Due to the high energy requirement for acetylene production and the risks associated with the handling of acetylene, an ethylene dichloride route with lower energy consumption was developed in the mid-20th century. Since then, the ethylene-based route has become dominant. Today, the hydrochlorination process of acetylene (Equation 1) is no longer used outside of China. In China, the availability of relatively inexpensive coal maintains this technology at an economically attractive level.

[0005] Ethylene-based VCM production is a balanced process, which means that all intermediates and by-products are recycled to ensure that the material balance is closed from ethylene, chlorine, and oxygen to the sole VCM as the final product. The ethylene-based route proceeds through the high-temperature chlorination of ethylene to produce 1,2-ethylene dichloride (EDC; 1,2-dichloroethane) (see Equation 2.1), followed by the thermal decomposition of EDC to produce VCM and hydrochloric acid (see Equation 2.2). (2.1)C 2 H 4 + Cl 2 → ClCH 2 -CH 2 Cl (2.2)ClCH 2 -CH 2 Cl → CH 2 =CHCl + HCl (ΔH = 71 kJ / mol)

[0006] The thermal decomposition of EDC is carried out through thermal cracking. Thermal cracking can be carried out in the liquid phase or the gas phase. However, liquid-phase processes are not industrially important because when EDC is treated with an alkaline solution, expensive chlorine is lost as salt. The disposal of aqueous process streams is also associated with several environmental problems. Therefore, the gas-phase route, which is carried out through thermal cracking or thermal decomposition, is the most industrially important for the production of VCM.

[0007] The gas-phase thermal cracking (thermal decomposition) from EDC to VCM consists of a complex series of Cl-catalyzed radical reactions and molecular reactions. Although Equation 2.2 represents the molecular reaction (the overall reaction), it does not include all the chemical processes that occur during the thermal decomposition of EDC to the VCM-containing product.

[0008] A conventional pyrolysis furnace 200 for EDC cracking is shown in Figure 2A. Gas-phase pyrolysis is highly endothermic and is thus typically carried out in a tubular coil made of Cr / Ni alloy, which is arranged in the furnace's firebox (radiation section). Depending on its configuration, 16 to 128 coils can be provided in the firebox. The furnace is typically lined with refractory material. The EDC stream passes through the radiant coil tubes. Here, reactions occur to produce VCM, hydrogen chloride (HCl), and by-products such as acetylene. The effluent gas rapidly reduces its temperature (product gas quenching) to avoid further decomposition of VCM and 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, where the condensed and cooled EDC is recycled at a high rate. In some cases, quenching is carried out in two stages, first by indirect cooling in a transfer line heat exchanger and then by direct quenching. This enables heat recovery for use in other process sections.

[0009] The heat required for the endothermic series of pyrolysis reactions is supplied by burning fuel in the firebox burner. The furnace may be equipped with a single or multiple burners. In most cases, the burner is fueled with natural gas. The heat carried out by the flue gas is recovered in the convection section of the furnace. The residence section is typically located above the firebox and consists of a series of tube banks. The heat recovered in the convection section can be used, for example, to preheat (evaporate) a hydrocarbon feed (about 200 °C) and a dilution medium.

[0010] Conventional pyrolysis furnaces employed for the thermal cracking of ethylene dichloride operate at an EDC conversion rate of 50 - 60%, 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. Although the EDC conversion rate increases with increasing temperature, the selectivity decreases. The operating conditions are typically selected based on a compromise, for example, between utility costs, productivity, and the frequency of shutdown times.

[0011] It is possible to maximize the selectivity of the VCM product to 99%, but in practice the EDC conversion rate remains moderate. This is because foulants and by-products are formed during the pyrolysis process, causing significant inefficiencies due to the large material throughput. For example, coke formation is inevitable in pyrolysis, and this coke formation requires periodic shutdowns of the entire plant for its removal. Other gas-phase by-products, such as chloroprene (C 4 H 5 Cl) and butadiene (C 4 H 6 ) also cause problems in the downstream distillation column. Adding a small amount (about 1200 ppm) of carbon tetrachloride (CCl 4 ) along with the EDC feedstock, an oxychlorination by-product, can slightly increase the conversion rate. Carbon tetrachloride can be used to increase the formation of free chlorine radicals and raise the conversion rate to about 60%. However, chlorine radicals also act as promoters for undesirable coke formation.

[0012] Today, although several configurations are available for the combustion furnace, most vinyl chloride producers are developing proprietary furnace technologies for optimal yields and low shutdown frequencies for pipe decoking. Nevertheless, tubular pyrolysis furnaces are still quite large and complex facilities with high greenhouse gas emission loads.

[0013] In view of improving the feed-to-product conversion ratio and efficiently and environmentally friendly drastically reducing greenhouse gas emissions, an update in the field of vinyl chloride (monomer) manufacturing technology is still desired.

Summary of the Invention

Problems to be Solved by the Invention

[0014] The object of the present invention is to solve, or at least mitigate, each of the problems arising from 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 units, and uses. In one aspect, a method for manufacturing vinyl chloride monomer (VCM) is provided according to what is defined in independent claim 1.

Means for Solving the Problems

[0015] In an embodiment, the method includes subjecting ethylene dichloride (EDC) to thermal cracking to produce a VCM-containing gaseous product, generating an amount of thermal energy required to heat an EDC-containing process fluid stream to a temperature at which the cracking reaction occurs, and transferring the thermal energy to the EDC-containing process fluid using a rotating device, the rotating device including a rotor having a plurality of rotor blades arranged in at least one row around a rotor hub mounted on a rotor shaft, a plurality of fixed guide vanes arranged in a row upstream of the rotor blades, and a fixed diffuser arranged downstream of the rotor blades, the rotor, the fixed guide vanes, and the diffuser being confined within a duct formed between at least one inlet and at least one outlet in the rotating device, and an amount of the thermal energy being generated within the rotating device by a series of energy conversions that occur when a fluid medium stream propagated between the inlet and the outlet inside the duct continuously passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively.

[0016] In an embodiment, the method includes subjecting EDC to thermal cracking in the rotating device, and initiating a cracking reaction in the EDC-containing process fluid propagating through the rotating device by adding an amount of thermal energy required for the cracking reaction to occur directly in the EDC-containing process fluid stream.

[0017] In an embodiment, the method includes subjecting the EDC to pyrolysis in a pyrolysis furnace suitable for the purpose, and the method - generating a heated fluid medium by adding a predetermined amount of thermal energy to the fluid medium propagating through the rotating device within the rotating device; - transferring the thermal energy to the pyrolysis furnace and using the fluid medium as a carrier for heating the EDC-containing process fluid stream flowing through the pyrolysis furnace to a temperature at which a cracking reaction occurs. The method further includes the following.

[0018] In an embodiment, the heated fluid medium used as the thermal energy carrier is any one of air, nitrogen gas, steam, flue gas discharged from the pyrolysis furnace, and any combination thereof. The pyrolysis furnace can be any cracking furnace suitable for the thermal cracking of an ethylene dichloride-containing feed.

[0019] In an embodiment, the method includes combining at least two rotating devices into a system, in which system, a first device is provided with a preheater function for (pre)-heating an EDC-containing process fluid, and a second device arranged downstream of the first device is provided with a thermal cracker function.

[0020] In an embodiment, the method further includes introducing a predetermined amount of input energy into the at least one rotating device, and by adjusting the amount of the input energy introduced into the at least one rotating device, the amount of thermal energy added to the fluid medium flow propagating through the rotating device is adjusted. In an embodiment, the input energy is electrical energy. In an embodiment, the amount of electrical energy introduced as input energy into the at least one rotating device is from about 5 percent to 100 percent.

[0021] In an embodiment, the electrical energy guided as the input energy into the at least one rotating device can be obtained from a renewable energy source, or different energy sources, optionally a combination of renewable energy sources.

[0022] In an embodiment, the method includes adjusting the velocity and / or pressure of a fluid medium flow propagating through the rotating device such that the amount of kinetic energy imparted to the fluid medium flow by rotating the blades of the rotor is sufficient to raise the temperature of the fluid medium to a predetermined value when the fluid medium flow exits at least one rotor blade row supersonically and passes through the fixed diffuser, where in the fixed diffuser the flow decelerates and dissipates kinetic energy into the internal energy of the fluid medium, and an amount of thermal energy is imparted to the fluid medium flow.

[0023] In an embodiment, in the method, the amount of thermal energy imparted to the fluid medium flow propagating through the rotating device is generated by generating a shock wave system while the fluid medium flow continuously propagates through a row of fixed guide vanes, the row of rotor blades, and the fixed diffuser, each in a controlled state.

[0024] In one aspect, a method for producing polyvinyl chloride (PVC) is provided according to that defined in independent claim 13. The method includes producing PVC through polymerizing a VCM product obtained by a method according to the previous aspect.

[0025] In one aspect, a vinyl chloride monomer (VCM) production unit for producing VCM from ethylene dichloride (EDC) through thermal cracking is provided according to that defined in independent claim 14.

[0026] In one aspect, it is provided to use the rotating device in generating vinyl chloride monomer (VCM) from ethylene dichloride (EDC) through thermal cracking according to that defined in independent claim 23.

Advantages of the Invention

[0027] The practicality of the present invention is due to various reasons according to each specific embodiment.

[0028] Overall, the object of the present invention is to improve the conventional EDC cracking process by incorporating the following rotating device during the process. The following problems associated with existing EDC cracking technology can be improved. That is, - By suppressing by-product formation, the selectivity of the main reaction "VCM production" is improved. - A one-through yield significantly exceeding that of a conventional EDC furnace is achieved. - The size of the equipment used for EDC cracking can be considerably reduced. - The formation of coke and other foulants is reduced, and by suppressing coke formation, the continuous operation time of the EDC cracking reactor is extended. - The energy efficiency of the EDC cracking process (energy used per unit mass of the produced VCM) is significantly improved. - The greenhouse gas emissions per unit mass of the produced VCM, for example, carbon dioxide emissions, are reduced through the electrification of EDC cracking / VCM production.

[0029] Overall, the rotating device used in the presently disclosed method enables direct or indirect input of heat into the EDC-containing process fluid, and the amount of heat input during the process is sufficient to initiate and maintain the cracking reaction of ethylene dichloride to produce vinyl chloride (monomer) to a predetermined extent.

[0030] Direct heating involves the propagation of the EDC-containing process fluid through a rotating device. In doing so, heating of the process fluid is achieved extremely rapidly, because there is no need to transfer heat from an external heater through the reactor wall. As a result of the absence of such an external heater, the reactor surface temperature is lowered. This significantly reduces the amount of coke formed during the cracking process. Thus, the cracker can be operated for longer periods between decoking shutdowns. Furthermore, direct heating can raise the temperature of the process fluid to a temperature above that of conventional EDC cracking (500 - 550 °C). This increases the EDC cracking reaction rate and, as a result, shortens the residence time that the reactants spend within the process space. As a result, the size of the EDC cracker can be considerably reduced. Alternatively, in a standard (unreduced) size unit, the once-through conversion rate can be improved.

[0031] Indirect heating involves heating a fluid other than the EDC-containing feed within the rotating device and then further using said fluid as a heat transfer medium to introduce thermal energy into the EDC pyrolysis furnace. This approach makes it possible to retrofit any existing EDC cracker into a low-emission, high-energy efficiency furnace. Since the combustion heater is replaced with a rotating device within a conventional furnace, no major changes to the infrastructure are required and thus it is extremely cost-effective.

[0032] The indirect heating approach is further associated with improved control of the cracking temperature. In a combustion heater, the flame temperature is extremely high, being 1800 - 2200 °C depending on the fuel and (air) preheating. These extremely high temperatures correspondingly heat the furnace coil tubes and cause acceleration of coking. By applying rotating device technology, the temperature of the EDC cracking furnace can be maintained at a lower level and the input heat can be distributed more uniformly throughout the furnace. This results in a reduced tendency to coke and, as a result, increases the conversion rate to a value well above the typical once-through conversion value of about 60%.

[0033] The present invention further enables reduction of greenhouse gas (CO, CO 2 , NO x , SOx) and particulate emissions generated in conventional EDC cracking. This can be achieved by an electrically driven rotating device and by incorporating said rotating device into a closed heating loop or a quasi-closed heating loop within a conventional EDC cracking plant. Thus, by reducing the heat loss of the flue gas, the energy efficiency of the process is improved. In a conventional heater, only a partial recycle of the flue gas is possible.

[0034] The expression "a number of" here means any positive integer starting from 1, for example 1, 2, or 3. The expression "a plurality of" here means any positive integer starting from 2, for example 2, 3, or 4. The terms "first" and "second" are used here simply to distinguish one element from another, unless expressly stated otherwise, and do not indicate any particular order or importance.

[0035] In the present disclosure, the terms "thermal cracking" and "pyrolysis" are used interchangeably.

[0036] In the present disclosure, the term "gasified" is utilized to indicate that a substance is converted into a gaseous form by any possible means.

[0037] By considering the detailed description and the accompanying drawings, various different embodiments of the present invention will become apparent.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0039] Detailed embodiments of the present invention are disclosed herein in relation to the accompanying drawings.

[0040] Figures 1A, 1B, 2B, and 3 schematically show the basic design for a method of manufacturing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) through a thermal cracking process according to an embodiment, and the basic design for related VCM generation units. The VCM generation method and the VCM generation unit generally formed to implement the method are thus denoted by a common reference numeral 101.

[0041] The VCM production unit can be further incorporated into any industrial system (not shown) including equipment configured to carry out an industrial process or a series of industrial processes aimed at obtaining vinyl chloride (monomer) from an industrial plant, a factory, or an ethylene dichloride-containing feed. The above-mentioned industrial plant may include additional units or facilities for manufacturing, extracting, and / or purifying related materials (e.g., raw materials, intermediates, products, and any auxiliary chemical substances employed in the process). The industrial plant can include, for example, ethylene chlorination facilities for producing 1,2-ethylene dichloride (EDC), and / or facilities for manufacturing polyvinyl chloride (PVC) by polymerization of VCM.

[0042] In one aspect, a method for producing vinyl chloride monomer (VCM) from ethylene dichloride (EDC) is provided by subjecting an EDC feed to thermal cracking (pyrolysis) to produce a VCM-containing gaseous product. An amount of thermal energy required to heat the EDC-containing process fluid stream to the temperature at which the cracking reaction occurs is generated, and the thermal energy is transferred to the EDC-containing process fluid stream using rotating devices 100, 100-1, 100-2.

[0043] Referring to FIGS. 4A, 4B, and 4C, various embodiments (100A, 100B, and 100C, respectively) of the rotating device 100 are schematically shown. Based on the following description, it is further assumed that those skilled in the art can implement the present invention using various different forms of the rotating device, including those not explicitly disclosed herein.

[0044] The rotary device 100 formed to directly or indirectly heat an EDC-containing process fluid stream includes a rotor having a plurality of rotor blades arranged in at least one row around a rotor hub mounted on a rotor shaft, a plurality of fixed guide vanes arranged in a row upstream of the rotor blades, and a fixed diffuser arranged downstream of the rotor blades. The rotor and the fixed components are confined within a duct formed between at least one inlet and at least one outlet within the rotary device. The amount of thermal energy required to directly or indirectly heat the EDC-containing process fluid stream to a temperature at which a cracking reaction occurs is generated within the rotary device by a series of energy conversions that occur as a fluid medium stream propagating between the inlet and the outlet inside the duct continuously passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively.

[0045] In a VCM production unit, the rotary device 100 (100A, 100B, and 100C) can be provided as a stand-alone device or as a predetermined number of devices arranged in series (continuously) or in parallel (forming an array). The device 100 operates on the concept that it can transfer the mechanical energy of the rotating shaft to a fluid medium and convert this fluid medium into the internal energy of the fluid through a series of fixed and rotating components within a predetermined number of work sections. When the fluid stream dissipates its kinetic energy into the internal energy of the fluid, it provides an amount of thermal energy (heat) to the fluid stream, thus increasing the fluid temperature. The aerodynamic configuration of the device 100 can vary.

[0046] Figure 4A shows axial-type devices 100, 100A. Inside this device, a rotating vane and a stationary vane are enclosed within an essentially tubular casing as described in Seppala et al.'s U.S. Patent No. 9,234,140. Figure 4B shows forms 100, 100B outlined in Xu and Rosic's U.S. Patent No. 10,744,480. In the case of forms 100, 100C shown in Figure 4C, the process fluid propagates between an inlet and an outlet along a flow path established based on an essentially helical orbit formed inside an essentially toroidal casing. The fluid flow continuously passes through a series consisting of stationary guide vanes, rotor blades, and stationary diffuser vanes. This type of device is detailed in Bushuev's U.S. Patent No. 9,494,038 and Seppala et al.'s U.S. Patent No. 9,234,140. Alternatively, a method based on an embodiment can also be further realized (not shown) using a rotating device formed to realize fluid flow along a flow path established by a fluid medium flow in the form of two spirals wound up as a lateral vortex ring as outlined in Bushuev's U.S. Patent No. 7,232,937. The above-mentioned documents are considered to be incorporated herein by reference.

[0047] In all forms 100A, 100B, and 100C, the device 100 includes a rotor system, hereinafter referred to as a rotor, which includes a rotor shaft 1 positioned along a horizontal (longitudinal) axis X-X' and a plurality of rotor blades (also called working blades) arranged to form at least one row around a rotor hub or rotor disk 3A mounted on the rotor shaft. The plurality of rotor blades arranged to form a (blade) row establish a rotor blade assembly or rotor blade cascade 3.

[0048] The rotating device further includes a drive system including at least one motor and an associated drive device for driving the rotor. The drive system is indicated by reference numeral 20 in FIG. 4A. 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). In addition to or instead of this, the rotating device can also be directly driven by, for example, a gas turbine or a steam turbine, or any other suitable drive device.

[0049] The device 100 further includes a fixed (stator) component formed to have a predetermined number of structures defining a reaction space (e.g., the casing 6), and a plurality of fixed vanes arranged to form at least one row adjacent to the corresponding rotor blade row. The device further includes a fixed diffuser. The fixed diffuser may or may not have vanes.

[0050] In some forms, the device includes a plurality of fixed guide vanes 2. These fixed guide vanes are arranged to form at least one row on the upstream side of the corresponding rotor blade row. The fixed guide vanes can be formed as fixed nozzle guide vanes (NGV). In some forms, the device additionally includes a plurality of fixed diffuser vanes 4. These fixed diffuser vanes are arranged to form at least one row on the downstream side of the corresponding rotor blade row. Each row of fixed vanes forms a fixed guide vane cascade 2 and a fixed diffuser vane cascade 4 respectively.

[0051] The term "cascade" (the crown of the blade) means an assembly of (working) blades attached around the rotor disk / rotor hub, or (fixed) blades attached directly or indirectly on the inner wall of the casing. For clarity, the fixed blades are referred to as "vanes" in the present disclosure.

[0052] The terms "upstream side" and "downstream side" essentially refer to the spatial and / or functional arrangement of a given part or component, here at least one rotor blade row, with respect to the direction of fluid flow (direction along axis X-X', see FIGS. 4A - 4C) across the entire device.

[0053] In some forms, it is possible to omit providing the diffuser vane cascade 4.

[0054] The device includes an airtight casing 6 (also called a gas casing or pressure casing). Inside the casing, an internal passage 7 is established in the form of a duct or conduit that extends between at least one inlet 8 and at least one outlet 9. The inner surface of the casing 6 faces the duct 7. In some forms, the duct 7 is defined by the inner surface of the casing. The shape of the duct / conduit 7 varies according to the device form.

[0055] In the present disclosure, the gas casing 6 is generally referred to as the device casing. In practice, the device 100 can be further enclosed within a separate external housing (see the external housing 14 shown in FIG. 4C).

[0056] The duct 7 formed inside the casing substantially completely surrounds the rotor, by a plurality of working blades integrated on the rotor, fixed guide vanes, and a diffuser.

[0057] In the device 100, the arrangement relationship of the fixed components and working components within the internal passage (duct 7) inside the casing, for example, the blade rows 2, 3, and 4, is such that a vane - less portion 7A (so - called vane - less space) is formed between the outlet from the diffuser 4, which in some cases is formed as a fixed diffuser vane row, arranged on the downstream side of the rotor blades, and the inlet to the fixed guide vane row 2 arranged on the upstream side of the rotor blades.

[0058] Device 100 is formed to have a predetermined number of basic sections, also called operation (process) sections. Each operation section is formed to have a continuous arrangement of a fixed guide vane 2 ("stator"), a rotor blade row 3 ("rotor"), and a diffuser 4 ("diffuser"). Together, these form a stator-rotor-diffuser section arrangement. The "diffuser" component in the arrangement can be formed to have a diffuser vane row, a vaneless diffuser, or a portion of a vaneless space arranged behind the rotor blades. A single-section or multi-section form including 2 to 30 rotor blade rows mounted on the rotor shaft is conceivable. Some exemplary multi-section forms include 10 to 20 rotor blade rows. In the multi-section form, the sections can be driven by the same or different (joined-type) rotor shafts.

[0059] In FIGS. 4A to 4C, the operation sections are indicated by Roman numerals (i-x; i-vii). The total number of sections is determined by the process duty, the required temperature and / or pressure level, and other process-related parameters.

[0060] The function of the basic section is to mediate the energy conversion cycle while the mechanical energy of the rotor shaft is converted into kinetic energy and then further into the internal energy of the fluid, subsequently increasing the fluid temperature. That is, the rotor is formed to impart mechanical energy to the process fluid, whereas the vaned or vaneless diffuser arranged downstream of the rotor is further formed to convert the mechanical (kinetic) energy of the process fluid into the internal energy of the process fluid. Within the diffuser region, the high-speed fluid flow reaching from the rotor is diffused with a significant entropy increase, whereby the flow dissipates the kinetic energy into the internal energy of the fluid substance, thus providing thermal energy into the fluid.

[0061] During the energy conversion cycle, the fixed guide vane row 2 arranged upstream of the rotor blade 3 prepares the required flow conditions at the entry of the rotating blade row (cascade). In the 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 can reach supersonic flow conditions.

[0062] The diffuser 4 arranged downstream of the rotor blade 3 converts the mechanical energy of the fluid into its thermal energy (heat). The fluid medium flow exits the rotor blade 3 and enters the diffuser at supersonic speed. When the flow on the upstream side of the diffuser is supersonic, the kinetic energy of the fluid flow is converted into the internal energy of the fluid through a system of multiple shocks and viscous mixing and dissipation. The flow dissipates its kinetic energy into the internal energy of the fluid flow propagating through the reactor (along the duct 7), thus adding an amount of thermal energy to the fluid. The increase in the internal energy of the fluid results in an increase in the fluid temperature.

[0063] In configuration 100A shown in FIG. 4A, the device is generally formed as an essentially tubular axial type turbomachine. The device 100A includes an elongated rotor 1 extending along a horizontal axis X-X'. A plurality of rotor blades are arranged along the rotor hub 3A to form a plurality of continuous rows, thereby forming a rotor blade cascade 3. The rotor 1 is enclosed inside a casing 6. The inner surfaces of the casing are provided with first and second fixed vane cascades 2 and 4 respectively. These fixed vane cascades are arranged such that the blades / vanes of the rotor cascade and the stator cascades 2, 3 and 4 are alternately positioned longitudinally (along the axis X-X') along the rotor 1. The fixed vane rows 2, 4 can be arranged on opposite sides of the casing (inner) surface facing the duct. Operating sections i-vii are established. Each section is formed to have a rotor blade cascade 3 and an adjacent stator vane pair 2, 4. A duct portion 7A without blades / vanes is arranged between subsequent sections.

[0064] The casing 6 may be conical in shape or may have an essentially constant cross-section along its entire length (not shown).

[0065] In the form 100B shown in Figure 4B, the rotating device 100 is formed as a radial turbo machine. The radial turbo machine generally follows the configuration for a centrifugal compressor or a centrifugal pump. The term "centrifugal" implies that the fluid flow inside the device is in the radial direction, and thus, the device 100B is called a "radial flow device". The device embodied in 100B includes a predetermined number of working sections (i-vii). Each section can be represented as having a stationary guide vane cascade 2, a rotor blade cascade 3, and a diffuser 4. The diffuser is mounted within a duct 7 and an essentially U-shaped conduit provided as a part of the duct 7 and a subsequent vane-less part 7A. The diffuser may be formed with or without diffuser vanes. In some embodiments, a vane-less U-shaped conduit arranged downstream of the rotor blade cascade can be adopted by its three-dimensional shape to form a diffuser region (see section v). Within this diffuser region, the mechanical energy imparted to the process fluid by the rotor is converted into heat. Although the state where a vane diffuser 4 is provided is shown in Figure 4B for sections ii and iii, the diffuser vane rows may be mounted, for example, downstream of each rotor blade cascade 3 (sections i-vii).

[0066] In addition to the multi-section forms 100A, 100B including a predetermined number of working sections continuously arranged along the rotor axis, the device 100 may include a predetermined number of sections arranged to form a regenerative multi-section form as shown in Figure 4C.

[0067] Figure 4C shows, in illustration (1), the form of the device 100C having two inlets 8 (8A, 8B) and two outlets 9 (9A, the second outlet is not shown). Other forms are also conceivable where appropriate.

[0068] The device 100 embodied as 100C has a substantially toroidal shape (a "doughnut" shape) of the casing 6 in three-dimensional form. Thereby, a rotor system (1, 3A, 3) with an associated bearing assembly (not shown) can be seen as filling an aperture that defines an opening in the central part of the toroid. In its meridional section, the casing 6 is essentially ring-shaped.

[0069] In the device 100C, fixed vane cascades 2, 4 are provided as essentially annular assemblies on both sides of the rotor blade cascade 3.

[0070] The device in form 100C further includes a flow shaping device (flow guiding device) 5 disposed inside the gas casing. The flow shaping device 5 is formed as an internal fixed ring-shaped structure, considering that this structure establishes an essentially annular duct inside the casing 6. The flow shaping device 5 may be provided as an annular, essentially hollow structure, for example, a hoop.

[0071] In form 100C, the internal passage is defined by the volume formed between the gas casing 6 (outer "doughnut") and the internal flow shaping device 5 (inner "doughnut"). This internal passage (duct 7) formed between the inner surface of the gas casing 6 and the outer surface of the flow shaping device 5 thus adopts an essentially annular shape with an essentially ring-shaped meridional section.

[0072] Inside the gas casing 6, the blade rows 2, 3, 4 are adjacent to each other such that the bladeless part 7A of the duct 7 is located between the outlet from the fixed diffuser blade row 4 and the inlet to the fixed guide vane row 2.

[0073] The operation sections are established to have three blade rows (2, 3, 4) as described above. In configuration 100C, the flow exiting from the diffuser blade row 4 of one section (e.g., section i) flows through a spiral (helico-toroidal) passage in the duct 7 / its vaneless portion 7A and then enters the fixed guide vane row 2 of the next section (section ii). The flow passes through the continuous blade rows 2, 3, 4 (section ii), exits the diffuser 4 (section ii), and continues towards the next section (iii - x) until the flow reaches the outlets 9, 9A (see illustrations (2) and (3)). Here, illustration 3 shows all sections i - x plotted on the same plane). The direction of the flow is indicated by the arrows.

[0074] In the VCM generation unit, at least two rotating devices may be connected in parallel and / or in series. The connection between the rotating devices 100 can be mechanical and / or functional. Cooperation between at least two individual, physically integrated, or non-integrated individual device units can establish a functional connection (e.g., a connection realized from the perspective of achievable heat input). In the latter case, the cooperation between at least two rotating devices can be established via a predetermined number of auxiliary devices (not shown). In some configurations, at least two rotating devices can be at least functionally connected via a rotor shaft so as to be mirror images of each other. The rotating devices connected in an array and / or arranged manner may have different types of drive engines, for example, an electric motor-driven reactor can be combined with a reactor driven by a steam turbine, a gas turbine, and / or a gas engine.

[0075] The method disclosed herein includes introducing an amount of input energy into the at least one rotating device 100. In an embodiment, the input energy includes electrical energy. In the present disclosure, the electrical input energy is defined in terms of power, i.e., the energy transfer rate per unit time (measured in watts). By adjusting the amount of the input energy, such as electrical energy, introduced into the at least one rotating device, the amount of thermal energy added to the fluid medium flow propagated through the rotating device can be adjusted.

[0076] The amount of electrical energy introduced as input energy into the at least one rotating device is provided at about 5 percent to about 100 percent. In some cases, the amount of electrical energy introduced as input energy is from about 50 percent to about 100 percent. The amount of electrical energy can be any one of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 percent (from the total input energy), or can occupy any intermediate value included between the above points.

[0077] Power (defined as the energy transfer rate per unit time) can be supplied into the rotating device by supplying current to an electric motor used to drive the rotating shaft of the device. The supply of power into the rotating device can be realized from an external source (to the rotating device 100 and / or the VCM generation unit). In addition to or instead of this, electrical energy can also be internally produced within the VCM generation unit and / or within a related industrial system (such as a plant or factory) incorporating the unit.

[0078] External sources include various support facilities provided for sustainable energy production. Thus, the power can be supplied from a power generation system utilizing at least one renewable energy source, or a combination of power generation systems utilizing different renewable energy sources. The external source of renewable energy can be provided as solar power generation, wind power generation, and / or hydroelectric power generation. Thus, the power may be received into the process from at least one of the following units, namely, a solar power generation system, a wind power generation system, and a hydroelectric power generation system. In some exemplary cases, a nuclear power plant may be provided as an external power source. Nuclear power plants are generally considered emission-free. "Nuclear power plant" should be construed to use traditional nuclear power and, in addition to or instead of this, fusion power.

[0079] Electricity can be supplied from a power plant that uses a turbine as a source of kinetic energy to drive a generator. In some cases, the power for driving at least one device 100 can be supplied from at least one gas turbine (GT) provided, for example, as a separate device or inside a cogeneration facility and / or inside a combined cycle power plant. The power can thus be formed from at least one of the following units, namely a combined cycle gas turbine plant (CCGT), and / or electricity production combined with heat recovery, and a cogeneration facility formed for utilization through combined heat and power (CHP). In some examples, the CHP plant can be a biomass combustion plant to increase the share of renewable energy in the described process. In addition to or instead of this, the power supply can optionally be realized from a spark ignition engine, such as a gas engine, and / or a compression engine, such as a diesel engine, provided as part of a engine power plant. Further, any conventional power plant formed to produce electrical energy from fossil fuels, such as coal, oil, natural gas, gasoline, and the like, typically mediated by the use of a steam turbine, can be used to generate electrical energy as input energy for the rotating device 100. Also, hydrogen can be utilized as a renewable energy source and, for example, reconverted to electricity using a fuel cell.

[0080] Any combination of the above-described power sources realized as external and internal sources is conceivable.

[0081] The introduction of input energy including power into the drive engine of the rotating device can further optionally involve using thermal energy generated elsewhere to direct the mechanical shaft output from the output turbine to the drive system. The shaft output is defined as the mechanical output transmitted from one rotating element to another and is calculated as the sum of the torque and rotational speed of the shaft. The mechanical output is defined as the amount of work or energy per unit time (measured in watts).

[0082] In practice, the shaft output from the electric motor and the output turbine can be split, for example, so that any one of them can provide all or part of the total shaft output.

[0083] Referring back to FIGS. 1A and 1B, embodiments are shown that involve using the rotating device 100 in the direct heating of a process fluid.

[0084] The method includes directly subjecting an EDC-containing process fluid to thermal cracking within the rotating device 100 (100A, 100B, 100C). The EDC-containing feed enters the device 100 via inlets 8, 8A, 8B (see FIGS. 4A - 4C), and the EDC-containing process fluid stream flows along duct 7 towards outlets 9, 9A, 9B following flow paths specific to each type of device. The amount of thermal energy required to heat the EDC-containing process fluid stream to the temperature at which the cracking reaction occurs is thus transferred directly to the EDC-containing process fluid flowing through the device, where it is added.

[0085] The amount of thermal energy required to heat the EDC-containing process fluid stream to the temperature at which the cracking reaction occurs is generated within the rotating device by a series of energy conversions that occur when a fluid media stream propagated between the inlet and the outlet within the duct successively passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively.

[0086] In the form schematically shown in FIGS. 1A and 1B, the rotating device 100 acts as a cracking reactor (cracking furnace).

[0087] The fluid flow propagating through apparatus 100 passes successively through several work sections, and for each passage, the temperature of the process fluid is raised by a specific value. More precisely, the temperature rise occurs as the process fluid flow exits the rotor blades and passes through the diffuser and the vaneless space. The temperature rise promotes the thermal decomposition of the feedstock species and their conversion to the desired products. The amount of thermal energy added to the medium is sufficient to initiate chemical decomposition reactions, specifically reactions that break the carbon - hydrogen (C - H) and carbon - chlorine (C - Cl) bonds. Thus, ethylene dichloride molecules present in the fluid flow decompose to yield low - molecular - weight vinyl chloride (monomer).

[0088] In an approach involving directly heating the reactants within apparatus 100, the EDC feed enters apparatus 100, preferably in gaseous form, together with possible co - reactants such as chlorine or chlorinated hydrocarbons. The gaseous feed passes through a series of stator - rotor - diffuser sections. As a result of propagating through each such section, a portion of the thermal energy is added into the process fluid (gas). This is because the kinetic energy input into the flow by the rotation of the rotor shaft / blades dissipates into the thermal energy of the fluid via the shock - wave system. The temperature of the process fluid increases with each subsequent section. In other words, the temperature of the process fluid increases step - by - step until the EDC cracking temperature value is reached and EDC decomposition begins. As the temperature rise continues, the EDC cracking reaction rate increases and an endothermic reaction starts, lowering the temperature of the reactants between sections. Since the gaseous reactants are passed through a predetermined number of sections, the desired conversion of the EDC feedstock is achieved. After being discharged from apparatus 100, the high - temperature product stream is rapidly cooled (quenched) to stop further progression of the reaction. The cooled product stream is led from the cooling device (e.g., quench tower, transfer line exchanger / TLE, and the like) towards a separation section (not shown).

[0089] Before entering apparatus 100, the EDC feed can be pre - heated to a predetermined temperature (inlet temperature).

[0090] The heat generation within the device 100 that acts as a cracking reactor (cracking furnace) occurs inherently in the process fluid via a mechanism in which kinetic energy dissipates as shock waves into thermal energy, and there is no need to transfer heat into the process fluid through the reactor surface (i.e., through the metal surface of the tubular coil), as typically done in a conventional cracking furnace equipped with a combustion heater. Therefore, the fluid medium propagating through the device can be heated to an extremely high speed. The residence time that the fluid spends passing through the working section (stator-rotor-diffuser arrangement) is on the order of less than a few seconds, for example, 0.1 to 10 milliseconds (0.0001 to 0.01 seconds). As a result, a heating rate that is several orders of magnitude faster than that in a conventional combustion heater is achieved. In a combustion heater, heat is transferred through the wall of the tube coil via conduction and convection.

[0091] Since there is no need to transfer external heat to the reactants, as a result of the absence of such an external heater, the reactor surface temperature is lower (compared to a conventional EDC cracker). Based on the lower surface temperature, the amount of coke and other foulants formed is reduced, and thus the operating period between decoking shutdowns is lengthened.

[0092] Due to the advantages shown above, the temperature of the process fluid can be increased to a temperature exceeding that of a typical EDC cracking treatment (500 - 550 °C).

[0093] Overall, process flow related parameters, such as flow rate and temperature, can be adjusted as desired. When the apparatus 100 is used as a cracking reactor, the temperature rise can be from about 10 °C to about 120 °C in one section. Thus, the fluid media flow propagating through the apparatus 100 can be heated in an extremely short period up to about 1000 °C in a "one-through" mode (considering a 100 °C temperature rise per section in a 10-section apparatus). This increases the EDC cracking reaction rate, significantly reduces the reaction time, and thus enables the achievement of the same one-through conversion rate in a reactor of a significantly smaller size (compared to a conventional cracking furnace).

[0094] Alternatively, by adjusting the operating temperature to a higher rate (i.e., higher than the "conventional" EDC cracking temperature), it is also possible to increase the one-through conversion rate within a reactor of a similar size.

[0095] FIG. 1A shows at 101, 101A a VCM production method and associated production units configured to crack EDC within a single apparatus 100 to produce VCM. The configuration of FIG. 1A is implemented by optimizing the reaction temperature to a level at which pyrolysis proceeds at a rate enabling EDC conversion within a single reactor device. The apparatus 100 (FIG. 1A) may be configured to immediately heat the EDC-containing feed, or the pyrolysis temperature may be achieved in a predetermined number of working sections (as described later in this specification).

[0096] The temperature of the fluid medium propagating through the operation sections of the apparatus 100 can be optimized as desired. Specifically, the temperature rise per section may be optimized so as to promote the thermal decomposition of EDC in all or selected sections. A form in which a predetermined number of operation sections (i-iv) are designated to have the function of (pre-)heating the EDC feed to a predetermined temperature is shown in detail in FIG. 1B. In the form shown in FIG. 1B, after passing through three or four so-called (pre-)heating sections, the process stream reaches the temperature at which the feed starts to decompose actively. In practice, the decomposition reaction may already occur after the process fluid has passed through the first operation group. The operation section inside the duct region where the actual cracking reaction occurs is called the reaction section.

[0097] FIG. 1B further shows a related production unit configured to crack EDC in a single apparatus 100 including a VCM production method and arrangement relationships (F1-F3) for increasing the residence time in the reaction section, designated as 101, 101B. The apparatus 100 of FIG. 1B thus includes hand sections for extracting process fluid from the apparatus and taking additional fluid into the apparatus. The additional fluid may be any one of a supply gas, a recycle gas, a makeup gas (so-called replacement / supplement gas), and a process fluid (e.g., transferred from a parallel apparatus), a dilution medium for either cooling / heating, and the like. In some cases, any one of the units F1, F2, and F3 inside the arrangement relationship may be formed as, for example, a heat exchanger for cooling the process fluid. Cooling of the process inside the reaction section may be used to further optimize the reaction yield.

[0098] Figure 2B shows, at 101, 101C, a method for generating VCM and a related generating unit according to another embodiment. The configuration of Figure 2B involves using the rotating devices 100, 100-1 in the indirect heating of a process fluid. In the method, the cracking of EDC may be carried out in any suitable pyrolysis furnace 200, including any type of conventional EDC cracker for that purpose. The furnace 200 may be formed as a cracking furnace suitable for the thermal cracking of an ethylene dichloride-containing feed.

[0099] An amount of thermal energy required to heat the EDC-containing process fluid stream to the temperature at which the cracking reaction occurs is generated, and the thermal energy is transferred to the EDC-containing process fluid using the rotating devices 100, 100-1. In the rotating device, by adding an amount of thermal energy to the fluid medium propagating through the rotating device, a heated fluid medium is generated. The heated fluid medium generated within the devices 100, 100-1 may be an inert gas, such as air, nitrogen, or steam, or any other substance suitable for the purposes of the present invention. The heated fluid medium transfers the thermal energy to the pyrolysis furnace 200 and is further used as a carrier for heating the EDC-containing process fluid stream flowing through the pyrolysis furnace to the temperature at which the cracking reaction occurs.

[0100] The heated fluid medium used as the thermal energy carrier can be any species selected from the group consisting of air, nitrogen gas, steam, flue gas discharged from the pyrolysis furnace, and any combination thereof.

[0101] By using apparatuses 100 and 100-1 to indirectly heat the EDC-containing process fluid, the performance of a conventional EDC cracking furnace can be improved. The operating principle of a conventional furnace, such as that shown in FIG. 2A, is that natural gas is burned inside the furnace fire chamber, and the flame and hot off-gas heat the reactor coil, and inside the reactor coil, the reactants for EDC cracking flow. After delivering a portion of this heat to the reactants, the still-hot off-gas is released to the atmosphere. Typically, the temperature of the flue gas exceeds about 120° C. to prevent condensation of water. Condensation of water can potentially form a corrosive environment along with acidic species in the off-gas.

[0102] FIG. 2B shows how apparatuses 100 and 100-1 can be used to replace combustion heating within the furnace. Inside apparatus 100-1, a fluid medium, such as an inert gas, is heated to a predetermined temperature, and the heated fluid medium is thus used to provide thermal energy to the EDC-containing process fluid flowing through the radiation coil of furnace 200.

[0103] When the hot effluent discharged from apparatuses 100 and 100-1 is used as the heating medium, no carbon dioxide emissions occur because incineration is not performed. The flue gas generated during the cracking process inside furnace 200 can be at least partially recycled to be used as the heating medium (optionally mixed with, for example, an inert gas) inside apparatuses 100 and 100-1 within unit 101 (101C, FIG. 2B). The amount of heat loss in the flue gas released to the atmosphere can be significantly reduced.

[0104] Using apparatus 100 as a heater in conjunction with a conventional EDC pyrolysis furnace 200 can reduce emissions and improve the energy efficiency of existing furnaces. The installation of apparatus 100 into an existing EDC cracker facility can be achieved with extremely low capital requirements since most of the process equipment does not need to be replaced. In order to enable heat transfer from the fluid (e.g., inert gas) heated within apparatus 100, 100-1 to the EDC-containing process fluid flowing through the coil, the existing furnace 200 can be provided with an appropriate piping arrangement around, for example, the reactor tube coil.

[0105] An additional advantage achieved in indirect heating is improved temperature control. In a conventional combustion heater, the flame temperature is extremely high, being 1800 - 2200 °C depending on preheating of the fuel and air. This specifically raises the temperature of the furnace tubes within the combustion section at the lower side of the furnace and accelerates coking. By means of apparatus 100, 100-1, the temperature of the cracking furnace 200 can be maintained at a lower level. Additionally, a uniform heat distribution across the entire furnace can be achieved. This significantly reduces the coking rate and enables the EDC cracking reaction to be promoted respectively to exceed the typical one-pass conversion range of 60% since coking is no longer a limiting factor.

[0106] Figure 3 shows yet another embodiment of the VCM production method and related production units at 101, 101D. In the form of Figure 3, at least two rotating apparatuses 100 are combined to form a system. Within the system, the first apparatus 100-1 is given a heater function for (pre)heating the EDC-containing process fluid (see the description regarding Figure 2B), while a second apparatus 100-2 arranged downstream of the first apparatus is given a thermal cracker function. Apparatus 100-2 is formed to perform direct heating of the EDC-containing process fluid and this can be realized as the apparatus described with respect to either Figure 1A or 1B.

[0107] If it is necessary to limit the reaction temperature (e.g., due to reasons of selectivity), the configuration of FIG. 3 can be applied. Compared with the apparatus 100 (FIG. 1B) including a (pre)heater section and a reaction section in the same reactor, the configuration of FIG. 3 involving at least two apparatuses 100-1, 100-2 enables the separation of the (pre)heating process and the reaction process. In design 101D, the (pre)heating and pyrolysis of the process fluid are carried out in different apparatuses 100-1, 100-2 respectively. The first apparatus in the arrangement can be used for (pre)heating the raw material, and the second apparatus in the arrangement can be used for EDC cracking. The production unit 101D can further include means for extracting the fluid from apparatuses 100-1, 102-2 (as described with respect to FIG. 1B) and for introducing the fluid into apparatuses 100-1, 102-2. Thus, either one of apparatuses 100-1, 100-2 may have the arrangement relationship (F1-F3) described in connection with FIG. 1B.

[0108] In all configurations involving directly heating the process fluid within apparatuses 100 (FIGS. 1A, 1B and 3), the reactor units 100, 100-2 can be configured to improve selectivity. Achieving a high reaction temperature inside the apparatus 100 in a short period of time can be beneficial in overcoming a low conversion rate.

[0109] The present invention further relates to a method for producing polyvinyl chloride (PVC), provided by a polymerization process of vinyl chloride monomer obtained by an embodiment of the above VCM production method. The polymerization of VCM may be carried out in any equipment suitable for the purpose.

[0110] In one aspect, the present invention relates to a vinyl chloride monomer (VCM) production unit for producing VCM from ethylene dichloride (EDC) through thermal cracking.

[0111] In an embodiment, the VCM generation unit includes at least one rotary device 100, 100A, 100B, 100C configured to generate an amount of thermal energy required to heat the EDC-containing process fluid stream to a temperature at which a cracking reaction occurs and to transfer the amount of thermal energy to the EDC-containing process fluid. The at least one rotary device includes a rotor having a plurality of rotor blades arranged in at least one row around a rotor hub mounted on a rotor shaft, a plurality of fixed guide vanes arranged in a row upstream of the rotor blades, and a fixed diffuser arranged downstream of the rotor blades, and the rotor and the fixed vanes are confined within a duct formed between at least one inlet and at least one outlet within the rotary device. The at least one rotary device is thus formed to generate an amount of thermal energy by a series of energy conversions that occur when a fluid medium stream propagated between the inlet and the outlet inside the duct continuously passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively.

[0112] The VCM generation unit can be formed to have at least two rotary devices connected in parallel and / or in series.

[0113] In an embodiment, at least one rotary device inside the VCM generation unit is provided with a thermal cracker function (see the descriptions related to FIGS. 1A, 1B, and 3).

[0114] In another embodiment, in the VCM generation unit, the at least one rotary device is provided with a (pre)heater function, and the (pre)heater function is formed to generate a heated fluid medium by adding an amount of thermal energy to the fluid medium propagating through the rotary device and to transfer the amount of thermal energy to a pyrolysis furnace, such as a tubular cracking furnace, formed to carry out thermal cracking of EDC to produce VCM (see the descriptions related to FIGS. 2B to 3).

[0115] The VCM generating unit can be formed to include at least two rotating devices that combine to form a system. In the system, a first device is provided with a preheater function for (pre)-heating an EDC-containing process fluid, while a second device arranged downstream of the first device is provided with a thermal cracker function (see the description regarding FIG. 3).

[0116] In another aspect, the present invention relates to the use of rotating devices 100, 100A, 100B, 100C in generating vinyl chloride monomer (VCM) from ethylene dichloride (EDC) through thermal cracking. The devices thus include a rotor having a plurality of rotor blades arranged in at least one row around a rotor hub mounted on a rotor shaft, a plurality of fixed guide vanes arranged in a row 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 confined within a duct formed between at least one inlet and at least one outlet in the rotating device. In the use, an amount of thermal energy required to heat the EDC-containing process fluid stream to a temperature at which a cracking reaction occurs is generated within the rotating device by a series of energy conversions that occur when a fluid medium stream propagated between the inlet and the outlet inside the duct continuously passes through the fixed guide vanes, the rotor blades, and the diffuser, respectively, and the amount of thermal energy is further transferred to the EDC-containing process fluid.

[0117] Embodiments of the present invention are further described in the following non-limiting examples.

Example

[0118] Direct heating This example is related to a configuration configured to directly heat the EDC feed (Figs. 1A, 1B, 3). The simulation data obtained in Example Cases 1 to 5 are summarized in Table 1. To simulate the performance of a conventional EDC cracking furnace (Comparative Example Case 1) and the rotating device 100 (Cases 2 to 5), AspenPlus V12.1 process simulation software (AspenTech) was used.

Table 1

[0119] Although pyrolysis involves hundreds of reactions with molecular compounds and radicals, considering that the pyrolysis reaction occurring in the EDC cracker involves by-products represented by the following components, namely EDC, VCM, hydrogen chloride (HCl), and acetylene (C 2 H 2 ), a simplified computer model was adopted to simulate the kinetic mechanism of thermal cracking (Reaction 1). Therefore, in addition to simulating the kinetic characteristics of the main reaction (Reaction 2a), the kinetic characteristics of the side reaction involving the formation of acetylene as a model by-product involved in coke formation were also simulated (Reaction 2b). Reaction 1. EDC → VCM → By-products Reaction 2a. EDC → VCM + HCL Reaction 2b. VCM → Acetylene + HCL

[0120] Case 1 is a comparative example. Here, the EDC cracking process was simulated in a conventional tubular furnace. In the case of Case 1, data on the furnace system and the kinetic mechanism of its simplified EDC cracking, as discussed by Li et al. (2013) [1], were used. Based on the above-mentioned literature source, the simulated furnace had two reactor coil trains (including 20 straight tubes and 19 bends per row) with an inlet tube diameter of about 0.1 m, and an EDC feed rate of 42 t / h, an inlet temperature of about 260 °C, and a pressure of 2400 kPa. Using these parameters, the residence time spent by the fluid passing through the coil was 26 - 27 s. The adiabatic volume (the last part of the reactor before quenching) was assumed to be equal in all cases. That is, the residence time in the adiabatic volume was about 0.06 s. The temperature profile across the entire reactor defines the degree of reaction. The temperature profile and mass fraction of Comparative Case 1 are shown in Figures 5A and 5B, respectively.

[0121] The temperature profile shown in Figure 5A is typical of a conventional EDC cracker. The process temperature steadily rises from 260 °C (the feed gas temperature) to about 400 °C. An endothermic reaction starts at 400 °C. From this point on, the rate of temperature increase decreases and becomes constant. The reaction rate is low in the first part of the reactor (see Figure 5B). As the EDC-containing process fluid propagates towards the reactor outlet, the chemical reaction rate increases to such an extent that immediate quenching is required.

[0122] Example Cases 2 - 5 were simulated with respect to apparatuses 100, 100A as shown in Figure 4A.

[0123] By modeling Case 2, it was shown that apparatus 100 operating at a temperature within the average EDC cracking range (T max 520 °C) could be successfully substituted for a conventional EDC cracker. The temperature profile and mass fraction profile of Case 2 are shown in Figures 6A and 6B, respectively.

[0124] Four reactor - rotor - diffuser arrays 2, 3, 4 were simulated for case 2 by four working sections realized in form 100A. Each section heats the EDC - containing gaseous process fluid by approximately 120 °C (ΔT = 120 °C). The first two sections are located at the beginning of the reactor and were assumed to represent the so - called (pre) - heating sections. These sections may be located within apparatus 100 (100A) formed as a thermal cracker (Figs. 1A, 1B), or alternatively these sections may be located within apparatus 100 - 1 formed as a (pre) - heater. In this simulation, the last two sections were assumed to represent the so - called reaction sections.

[0125] In the simulation involving a single reactor unit 100 (Figs. 1A, 1B), the reactor is heated to 510 °C within 1 to 5 milliseconds (during the period of the first two pre - heating sections). At this point, with the decomposition of EDC, the temperature of the gas flow decreases based on the endothermic reaction between the sections (the EDC - containing process fluid passes through the non - vane part of ducts 7, 7A). A residence time of about 6 seconds is allowed until the process fluid enters the third working section so that it is reheated to about 520 °C. Thereafter, the process temperature can decrease again, and the process is reheated to about 520 °C in the last fourth working section. Based on the endothermic reaction occurring in the process fluid, at the reactor outlet, the process fluid can have a lower temperature compared to a conventional reactor furnace (compare the graphs in Figs. 5A and 6A). In various forms (100A, 100B or 100C), apparatus 100 can be formed to have a heat - insulating volume inside the reactor (the part between the last working section and the reactor outlet of duct 7) optimized to meet the requirements of the process. Optimization may be carried out by modifying (e.g., reducing or expanding) the three - dimensional spread inside the apparatus that houses the heat - insulating volume.

[0126] The acetylene generation rate is significantly lower at the outlet of the conventional cracker apparatus 100. This reduces coke formation in the reaction region of apparatus 100 and at its outlet.

[0127] Overall, the residence time required for the cracking reaction to occur is shorter in the case of apparatus 100. This is because a higher reaction temperature (T max ) can be achieved.

[0128] For apparatus 100 operating at a temperature deviating from the average EDC cracking temperature (assumed to be approximately 520 °C; see Case 2), Cases 3 and 4 were modeled. Case 3 was configured to correspond to an operating temperature lower than the average EDC cracking temperature, while Case 4 was configured to correspond to an operating temperature higher than the average EDC cracking temperature. On the other hand, for apparatus 100 operating at the same maximum temperature (T max 480 °C) as that of a conventional EDC cracking furnace in Case 1, Case 3 was modeled. For apparatus 100 operating at a maximum temperature (T max 600 °C) higher than that of a conventional EDC cracking furnace, Case 4 was modeled. The heat input per section was the same as before, i.e., ΔT = 120 °C. That being said, the delta T parameter can be optimized according to each case. The temperature profiles and mass fraction profiles for Cases 3 and 4 are shown in FIGS. 7A, 8A, 7B, and 8B, respectively.

[0129] Both Cases 3 and 4 reach a higher conversion rate than a conventional cracker (Case 1). The decrease in the operating temperature (Case 3) lengthens the residence time that the process fluid spends in the reactor beyond the residence time typically required for the pyrolysis reaction to occur. Thus, it seems beneficial to carry out the process of Case 3 in apparatus 100 formed as suggested by FIG. 1B. Increasing the operating temperature (Case 4) shortens the required residence time to approximately one-tenth of the required residence time in a conventional cracker.

[0130] An even more notable difference between Case 3 and Case 4 is selectivity. The simulated kinetic characteristics suggest that lower temperatures and longer residence times (Case 3) improve process selectivity compared to the conventional cracking furnace of Case 1. This reduces coke formation and offers the possibility of reaching a higher conversion rate in the cracking process.

[0131] Most of the by-products, such as acetylene, are produced at the end of the cracking process. In the kinetic model used here, the acetylene formation reaction is driven by an increase in the VCM concentration. High reaction temperatures also promote the generation of acetylene. Therefore, the combination of high reaction temperature and high conversion rate is an undesirable situation.

[0132] Case 5 aims to distinguish whether rapid heating to a high temperature (the reaction temperature at which EDC pyrolysis occurs) at the beginning of reactor 100 has a favorable effect on selectivity. Case 5 was simulated in four operating sections. Here, each section is defined as the stator-rotor-diffuser arrays 2, 3, 4. Contrary to Case 2, in this Case 5, all four sections are located directly at the reactor inlet within the first part of the reactor to immediately heat the feed gas to an unusually high temperature of almost 730 °C. The temperature profile and mass fraction profile of Case 5 are shown in Figures 9A and 9B, respectively.

[0133] In Case 5, the reaction starts with rapid EDC decomposition. Within approximately 40 milliseconds, a conversion rate of about 13% is achieved, and a conversion rate of about 50% is reached within 1 second. The process fluid reaches the adiabatic volume at the end of the reactor during only a 5.3-second period (residence time = 5.3 s). During that time, a 60% EDC conversion rate is achieved. However, contrary to our initial assumption that the formation of acetylene can be controlled by such an immediate heating step (due to the increase in VCM concentration as the process fluid temperature decreases), the system demonstrates lower selectivity to VCM and higher acetylene concentration.

[0134] Heat loss According to the literature source (see, for example, Li et al. [1]), conventional cracking uses approximately 1000 kg / h of fuel gas. From the heat of combustion, it can be estimated that the total energy output of the furnace is 13 MW. The simulation estimates that a conventional EDC cracker requires approximately 8.3 MW of energy to heat the process fluid in which the cracking reaction occurs. This leads to flue gas losses of approximately 4.7 MW. According to the above reference, the temperature of the flue gas at the furnace outlet (which is the cause of most of the heat loss) is 900 K, calculated back near atmospheric conditions using the estimated heat capacity, and the decrease in flue gas temperature results in essentially the same energy loss value. Thus, approximately 36% of the heat input to a conventional EDC cracker is lost.

[0135] On the other hand, when the rotating device 100 is used for direct heating of the raw material (FIGS. 1A, 1B, 3), the heat loss can be negligible, and these heat losses mainly occur based on the motor output and drive efficiency. For example, the efficiency of the rotating device 100 driven by an electric motor is estimated to be approximately 94%. Thus, its energy loss is approximately one-sixth the size of that occurring in a conventional EDC cracker.

[0136] The heat input and heat loss for Cases 1 - 5 are shown in Table 2.

Table 2

[0137] The higher heat input in Case 4 is explained by the provision of an additional work section. In Case 4, additional heat not consumed by the endothermic reaction to provide an increasing conversion rate becomes available for further incorporation into feed heating (through recycling). The difference in the value specifying the amount of heat utilized within the reactor is related to the difference in the outlet temperature and conversion rate.

[0138] Indirect heating The following examples relate to the form adopted for indirectly heating the EDC feed in the cracking furnace 200. Here, the apparatuses 100, 100-1 are provided with a (pre)heating function. Accordingly, with the indirect heating using the rotating apparatuses 100, 100-1, the cracking reaction and the pyrolysis temperature profile could each proceed as suggested by Case 1, but in this case, the coil tube temperature could be decreased and the amount of coke formation was reduced, which is different. The local temperature difference inside the cracker furnace also became smaller.

[0139] The main advantage of the indirect heating approach is energy efficiency. Since no flue gas is generated, by recycling the heating medium (i.e., the heat transfer medium), it can be returned to the rotating apparatus for reheating. Assuming a rather high purge rate of 5%, the heat loss resulting from the flue gas is 5% of that of a conventional EDC cracker at 0.23 MW. Additional losses occur due to the motor output and drive efficiency. With the heat consumption in the cracking furnace (200) being about 8.3 MW and about 0.23 MW being stored due to flue gas loss, the rotating apparatuses 100, 100-1 must generate about 9.1 MW of heat. The heat loss can be estimated to be 0.54 MW. Accordingly, the total heat loss in the indirect heating approach is about 0.79 MW, which is slightly more than one-tenth of the losses observed in a conventional EDC cracker.

[0140] As will be apparent to those skilled in the art, with the development of technology, the basic idea of the present invention can be realized and combined in various ways. The present invention and its embodiments are thus not limited to the above examples and can vary widely within the scope of the appended claims.

[0141] References: [1] Chaochun Li, Guihua Hu, Weimin Zhong, Hui Cheng, Wenli Du, and Feng Qian, Comprehensive Simulation and Optimization of an Ethylene Dichloride Cracker Based on the One-Dimensional Lobo-Evans Method and Computational Fluid Dynamics, Ind. Eng. Chem. Res. 2013, 52, 2, 645-657.

Claims

1. A method (101, 101A, 101B, 101C) for producing vinyl chloride monomer (VCM), said method comprising subjecting ethylene dichloride (EDC) to thermal cracking to produce a VCM-containing gaseous product, thermal energy required to heat an EDC-containing process fluid stream to a temperature at which a cracking reaction occurs is generated, and said thermal energy is transferred to said EDC-containing process fluid using a rotating device (100), said rotating device (100) comprising a rotor provided with a plurality of rotor blades (3) arranged in at least one row around a rotor hub (3A) mounted on a rotor shaft (1), a plurality of fixed guide vanes (2) arranged in a row upstream of said rotor blades, and a fixed diffuser (4) arranged downstream of said rotor blades and comprising, said rotor, said fixed guide vanes, and said diffuser are confined within a duct (7) formed between at least one inlet (8) and at least one outlet (9) within said rotating device, the thermal energy is generated within said rotating device by a series of energy conversions that occur when a fluid medium stream propagated between said inlet and outlet within said duct successively passes through said fixed guide vanes (2), said rotor blades (3), and said diffuser (4), A method (101, 101A, 101B, 101C) for producing vinyl chloride monomer (VCM).

2. The method according to claim 1 (101, 101A, 101B), comprising subjecting EDC to thermal cracking within said rotating device (100), and initiating a cracking reaction in an EDC-containing process fluid propagating through the rotating device by adding an amount of thermal energy required for said cracking reaction to occur directly in the EDC-containing process fluid stream.

3. The method comprising subjecting EDC to thermal decomposition in a pyrolysis furnace (200) suitable therefor, said method - generating a heated fluid medium by adding thermal energy to said fluid medium propagating through said rotating device within said rotating device, - Using the fluid medium as a carrier for transferring thermal energy to the pyrolysis furnace (200) and heating the EDC-containing process fluid stream flowing through the pyrolysis furnace to a temperature at which a cracking reaction occurs. The method (101, 101C) according to claim 1, further comprising.

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

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

6. Including combining at least two rotating devices (100) into a system, wherein within the system, a first device (100-1) is provided with a preheater function for (pre)heating an EDC-containing process fluid, and a second device (100-2) disposed downstream of the first device is provided with a thermal cracker function. The method (101, 101A, 101B, 101C) according to any one of claims 1 to 5.

7. Further comprising introducing input energy into the at least one rotating device, and adjusting the amount of the input energy introduced into the at least one rotating device, whereby the amount of thermal energy added to the fluid medium stream propagated through the rotating device is adjusted. The method (101, 101A, 101B, 101C) according to any one of claims 1 to 6.

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) according to claim 8, wherein the amount of electrical energy introduced as input energy into the at least one rotating device (100) is from about 5 percent to 100 percent.

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

11. When the fluid medium flow exits at supersonic speed from at least one rotor blade row and passes through the fixed diffuser (4), the kinetic energy is added to the fluid medium flow by rotating the blades (3) of the rotor in an amount sufficient to raise the temperature of the fluid medium to a predetermined value, including adjusting the velocity and / or pressure of the fluid medium flow propagating through the rotary device (100), and in the fixed diffuser, the flow decelerates and the kinetic energy dissipates into the internal energy of the fluid medium, and thermal energy is added to the fluid medium flow. The method (101, 101A, 101B, 101C) according to any one of claims 1 to 10.

12. The thermal energy added to the fluid medium flow propagating through the rotary device (100) is generated by generating a shock wave system while the fluid medium flow continuously propagates through the fixed guide vane row (2), the rotor blade row (3), and the fixed diffuser (4) in a respectively controlled state. The method (101, 101A, 101B, 101C) according to claim 11.

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

14. A vinyl chloride monomer (VCM) production unit (101, 101A, 101B, 101C) for producing VCM from ethylene dichloride (EDC) through thermal cracking, the unit comprising at least one rotary device (100) formed to generate the thermal energy required to heat the EDC-containing process fluid flow to the temperature at which the cracking reaction occurs and to transfer the thermal energy to the EDC-containing process fluid, the rotary device (100) a rotor provided with a plurality of rotor blades (3) arranged to form at least one row around a rotor hub (3A) mounted on a rotor shaft, a plurality of fixed guide vanes (2) arranged to form a row upstream of the rotor blades, and a fixed diffuser (4) arranged downstream of the rotor blades and including The rotor and the stationary vane are confined within a duct (7) formed between at least one inlet (8) and at least one outlet (9) within the rotating device, the at least one rotating device is configured to generate thermal energy by a series of energy conversions that occur when a fluid medium flow propagated between the inlet and the outlet inside the duct successively passes through the fixed guide vane (2), the rotor blade (3), and the diffuser (4), vinyl chloride monomer (VCM) production units (101, 101A, 101B, 101C).

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

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

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

18. The VCM production unit (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, comprising at least two rotating devices combined into a system, wherein within the system, a first device (100-1) is provided with a preheater function for (pre)heating an EDC-containing process fluid, and a second device (100-2) arranged downstream of the first device is provided with a thermal cracking function.

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

21. The at least one rotating device (100) is formed along a flow path established based on any one of an essentially spiral orbit formed inside an essentially toroidal casing, an essentially spiral orbit formed inside an essentially tubular casing, and an essentially radial orbit, and along a flow path established by a fluid medium flow in the form of two spirals wound as a left-right vortex ring, and is formed to realize a fluid flow between an inlet (8) and an outlet (9). The VCM generation unit (101, 101A, 101B, 101C) according to any one of claims 14 to 20.

22. A rotor including a plurality of rotor blades (3) arranged in at least one row around a rotor hub (3A) mounted on a rotor shaft (1), a plurality of fixed guide vanes (2) arranged in a row upstream of the rotor blades (3), and a diffuser (4) arranged downstream of the rotor blades (3), wherein the rotor, the plurality of fixed guide vanes, and the diffuser are confined within a duct (7) formed between at least one inlet (8) and at least one outlet (9) in the rotating device (100). It is used in generating vinyl chloride monomer (VCM) from ethylene dichloride (EDC) through thermal cracking. The heat energy required to heat the EDC-containing process fluid flow to the temperature at which the cracking reaction occurs is generated within the rotating device (100) by a series of energy conversions that occur when the fluid medium flow propagating between the inlet (8) and the outlet (9) inside the duct successively passes through the fixed guide vanes (2), the rotor blades (3), and the diffuser (4), and the heat energy is further transferred to the EDC-containing process fluid. Use of the rotating device (100).

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