Method for improving glacial acetic acid process control

Abstract

A method of measuring the concentration of a component. The method comprises providing a system (10, 20) configured for contacting a first component, a second component, and a third component; determining the concentration of the second component in the reactor (10); measuring the concentration of the third component in the reactor; determining the temperature and pressure of a first device (20) downstream of the reactor; and calculating a first concentration of the first component in the reactor based on (i) the concentration of the second component in the reactor, (ii) the concentration of the third component in the reactor, and (iii) the temperature and pressure of the first device.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is filed under the Patent Cooperation Treaty, which claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 343,690 filed on May 19, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to the production of acetic acid. More specifically, the present disclosure relates to methods of controlling the production of acetic acid. Background Art

[0004] In some glacial acetic acid processes, maintaining a steady-state reactor methyl acetate concentration may depend on one or more variables, such as methanol feed, carbon monoxide feed, and / or active catalyst (eg, rhodium) concentration.

[0005] For processes operating at methyl acetate reactor concentrations greater than 3 wt.%, mismatches in any methyl acetate dependent variables can, in some cases, result in rapid increases in methyl acetate concentration, increasing the likelihood of significant upsets in downstream equipment and plant trips.

[0006] Several different methods have been devised to make direct or indirect methyl acetate measurements. Since reactor methyl acetate is generally inversely proportional to the decanter heavy phase density, one method relies on an online heavy phase density measurement to calculate the reactor methyl acetate concentration. However, this method has several disadvantages. For example, since the decanter is downstream of the reactor, there is a time lag. The method is reactive rather than an active technique. Other reactive methods for controlling methyl acetate concentration include controlling the carbon monoxide flow rate in response to temperature.

[0007] Some methods directly measure reactor methyl acetate and other reactor components in real time by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy (see, e.g., U.S. Pat. No. 6,103,934; U.S. Pat. No. 6,362,366; U.S. Pat. No. 8,519,182; and U.S. Pat. No. 10,227,283). These methods typically use flow cells or in situ probes. While these methods can help improve process control, they may face one or more difficulties.

[0008] For example, in both the near infrared (NIR FTIR) and Raman spectra of the reactor solution, the methyl acetate peak at least partially overlaps with other peaks, which can adversely affect the accuracy of the measurement. As another example, random signal fluctuations in the Raman spectrum can result in the need for normalization to prevent over-prediction or under-prediction of component concentrations (see, e.g., U.S. Pat. No. 9,656,939; and U.S. Pat. No. 10,118,884).

[0009] There remains a need for methods for directly or indirectly measuring one or more reactor components such as methyl acetate, including reliable methods for measuring methyl acetate in real time so that upward and / or downward trends in methyl acetate concentration can be quickly identified. Summary of the invention

[0010] One aspect of the present disclosure relates to methods for measuring one or more reactor components, including methods in which a pseudo-analyzer or surrogate analyzer is used as (i) a cross-check of FTIR and / or Raman analyzer data, or (ii) an independent method for calculating the concentrations of various reactor components in real time.

[0011] One aspect of the present disclosure relates to a method of calculating the concentration of a first component in a reactor based on (i) the concentration of a second component in the reactor, (ii) the concentration of a third component in the reactor, and (iii) the temperature and pressure of a first device downstream of the reactor.

[0012] Yet another aspect of the present disclosure relates to a method comprising providing a system configured for contacting a first component, a second component, and a third component, wherein the system comprises a reactor and a first device downstream of the reactor; determining a concentration of the second component in the reactor; determining a concentration of the third component in the reactor; determining a temperature and a pressure of the first device; and calculating a first concentration of the first component in the reactor based on (i) the concentration of the second component in the reactor, (ii) the concentration of the third component in the reactor, and (iii) the temperature and the pressure of the first device.

[0013] Other aspects will be described in part in the subsequent description, and in part will be apparent from the description, or can be learned by practicing the aspects described herein. The advantages described herein will be realized and obtained by the elements and combinations specifically pointed out in the appended claims. It should be understood that the above general description and the following detailed description are exemplary and illustrative, rather than restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The claimed subject matter may be understood by reference to the following description in conjunction with the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0015] Figure 1 is a schematic diagram of an exemplary acetic acid production system according to an embodiment of the present technology;

[0016] Figure 2 Examples of computing and networking devices are shown;

[0017] Figure 3 Exemplary elements of systems and networked systems are shown;

[0018] Figure 4depicts an overlay of (i) methyl acetate concentration measured by Raman spectroscopy and (ii) methyl acetate concentration predicted by correlation with Raman composition input; and

[0019] Figure 5 Depicted are overlays of (i) methyl acetate concentration measured by Raman spectroscopy and (ii) methyl acetate concentration and associated water concentration predicted using methyl iodide concentration measured by Raman spectroscopy.

[0020] Although the disclosed processes, methods and systems are susceptible to various modifications and alternative forms, the accompanying drawings show by way of example specific embodiments described in detail herein. However, it should be understood that the description of specific embodiments herein is not intended to limit the invention to the specific forms disclosed, but rather, the invention is intended to cover all modifications, equivalents and substitutions falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0021] A detailed description of the embodiments of the disclosed processes and methods is as follows. However, it should be understood that the described embodiments are merely examples of processes and methods, and that the processes and methods can each be implemented in various and alternative forms of the described examples. Therefore, the specific procedural, structural, and functional details involved in the embodiments described herein should not be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching those skilled in the art to adopt the disclosed processes and methods in various ways.

[0022] The expression "MeI" is used herein as an abbreviation for methyl iodide. The expression "HI" is used herein as an abbreviation for hydrogen iodide. Unless specifically indicated otherwise, the expression "wt. %" as used herein refers to the weight percentage of a particular component in the composition mentioned. With respect to all ranges disclosed herein, such ranges are intended to include any combination of the upper and lower limits mentioned, even if a particular combination is not specifically listed.

[0023] Embodiments of the disclosed processes and systems relate to the production of acetic acid by carbonylating methanol in a carbonylation reaction. The carbonylation reaction can be represented as: CH3OH+CO→CH3COOH.

[0024] Embodiments of the disclosed process generally include: (a) contacting a plurality of components in an acetic acid production system having a reactor and a first device downstream thereof; and monitoring; and (b) determining the concentration of the first component in the reactor based on the respective concentrations of the second and third components in the reactor and the temperature and pressure of the first device. The following description sets forth the disclosed process in detail.

[0025] Acetic acid reaction system

[0026] like Figure 1 An exemplary acetic acid manufacturing plant implementing the methanol carbonylation technology schematically depicted in Figure 1 can be conveniently divided into three functional areas: reaction, light ends recovery and purification. The acetic acid reaction system can vary in the type and number of distillation columns, such as described in U.S. Patents Nos. 3,772,156, 4,039,395, 5,831,120, 5,227,520, 5,416,237 and 5,916,422 and PCT Publication WO98 / 22420, and such variations within the skill of those of ordinary skill in the art are included within the scope of the present disclosure. Generally, the reaction section consists of a reactor 10 and a flash tank 20. The light ends recovery section consists of a light ends column 30 and a phase separation vessel 40 (decanter). The purification section also consists of a light ends column 30 as well as a drying column 50 and an optional heavy ends column 60. Various columns and containers are connected by transfer lines such as pipes, and the reaction system solution usually flows through the transfer lines with the help of pumps. For ease of description and discussion, the term "stream" is used herein to refer to the transfer lines and flows therein as the same transfer lines and flows.

[0027] The feed of reactor 10 is via a stream 12 including methanol, dimethyl ether, methyl acetate or a mixture thereof. Water may also be present in stream 12. Carbon monoxide or a mixture with an inert gas is also fed to the process via stream 12. During normal reactor 10 operation, the reactor contents are continuously taken out as a liquid. This is achieved by flashing the reactor solution through a valve (not shown) to produce a vapor-liquid stream 100, which is sent to a flash tank 20 where the vapor is separated from the liquid. The liquid containing the catalyst accumulates in the bottom 22 of the flash tank 20 and is pumped back into the reactor 10 via stream 110 by a catalyst recirculation pump P1. The vapor stream 120 leaving the top 24 of the flash tank 20 contains acetic acid product, water, methyl iodide (MeI), hydrogen iodide (HI) and low levels of impurities, i.e., propionic acid and acetaldehyde. The vapor is fed to a light ends column 30. Therefore, the main purpose of the flash tank 20 is to separate the catalyst from the crude product and return the catalyst to the reactor 10.

[0028] Light ends column 30 is critical to the entire process because it serves the dual purpose of crude acetic acid purification and recycling iodide back to the reaction section. Light ends column 30 is fed by overhead vapor stream 120 from flash tank 20. It allows higher boiling acetic acid to be separated from lower boiling components such as MeI and methyl acetate (MeOAc). Three streams 130, 140, 150 are removed from light ends column 30. Overhead stream 130 consists primarily of MeI, but also contains some water, MeOAc and acetic acid, and is sent to a phase separator or decanter 40 described below. Side draw stream 140 from light ends column 30 consists of wet acetic acid, which is sent to drying tower 50 by pump P5. Light ends bottoms stream 150 removed from bottom 34 of light ends column 30 consists of water, HI and acetic acid, which is recycled to the reaction section including reactor 10 and flash tank 20.

[0029] The second part of the light ends recovery section is a phase separator 40, more commonly referred to as a decanter. In the decanter 40, a heavy phase 42 consisting mainly of MeI and an immiscible light phase 44 consisting mainly of aqueous acetic acid are separated. The main purpose of this separation of light phase 44 and heavy phase 42 is to recycle MeI to the reactor 10. The MeI to be recycled is collected in a small sleeve 46 of the decanter 40, whose volume is much smaller than the volume of the remaining top portion 48 of the decanter 40 including the light phase 44. The MeI in the sleeve 46 is recycled to the reactor 10 via a bottom stream 160 by pump P2. The second purpose of the light phase separation is to return some light phase 44 as reflux to the light ends column 30 via a stream 170 by pump P4, and the remaining part of the light phase 44 is recycled to the reactor 10 via a stream 180 by pump P3. The amount of the light phase directed to stream 170 relative to stream 180 is adjusted relative to one or both of pumps P3 and P4.

[0030] Many acetic acid processes include additional treatment of the heavy phase 42 and the light phase 44. In processes described, for example, in U.S. Pat. Nos. 4,102,922, 5,371,286, and 5,599,976, the heavy phase 42 is further treated to remove alkanes. One such process is shown in Figure 1In the embodiment of the present invention, a hydrocarbon removal column 70 is fed by a portion of the heavy phase 42 via stream 210. The overhead distillate of column 70 is returned to flash tank 20 via stream 220. The bottom residue rich in alkanes is sent to waste via stream 230. Many acetic acid processes have additional treatment of the heavy phase 42 and the light phase 44 to remove impurities such as acetaldehyde and its condensation products. Examples of such acetaldehyde removal systems are described in U.S. Patents Nos. 5,599,976, 5,723,660, 5,625,095 and 5,783,731, European Patent No. 487,284 and PCT Publication WO9817619. Various acetic acid process streams can be analyzed using embodiments of the present disclosure to provide improved control of individual process steps as well as overall process control.

[0031] As described above, the purification includes a light ends column 30, as well as a drying column 50 and a heavy ends column 60. Many acetic acid processes include an additional column 80 to strip acetic acid from higher boiling impurities. The drying column 50 is a large distillation column that takes the wet acetic acid stream 140 from the light ends column 30 as its feed via pump P5. As its name implies, the main purpose of the drying column 50 is to remove water from the product acetic acid. Water is removed from the top of the column via stream 184 to the overhead drum 56 and returned to the reaction section via pump P8 via stream 186. A portion of the condensed solution in the drum 56 is returned as a tower reflux via pump P9 via stream 188. In some acetic acid processes, such as in U.S. Pat. Nos. 5,599,976 and 5,723,660, a portion of the overhead stream 184 condensed in the drum 56 is added to the light ends column 30 or the drying column feed stream 140 via a transfer line (not shown). The present disclosure provides improved process control of the methods described in the above patents. Dried acetic acid is removed from the bottom 52 of the drying column 50 and pumped directly to a product tank (not shown) or to the heavy ends column 60 via stream 190 by pump P6 to further remove impurities such as propionic acid. Additional acetic acid can be recovered from stream 197, which is fed to the spent acid stripping column 80 by pump P7. The recovered acetic acid is returned to the heavy ends column 60 via stream 198. Spent propionic acid and higher acids are sent for processing via stream 199. The overhead of the heavy ends column 60 is sent to drum 64 via stream 192, condensed, and returned to the heavy ends column 60 via stream 196 by pump P10 as reflux, or sent via stream 194 to mix with stream 140.

[0032] The purpose of optional heavy ends column 60 is to remove high boiling propionic acid impurities from acetic acid. The bottom 62 of heavy ends column 60 is mainly composed of propionic acid, while side draw stream 200 is composed of pure acetic acid, which is sent to the product tank for storage. When side draw stream 200 does not meet the specifications, stream 200 can be transferred to re-run tank 208 instead of being sent to the product tank. When side draw stream 200 meets the specifications, it is sent to the product tank. The contents of re-run tank 208 can be reprocessed by introducing stream 205 into drying tower 52. In some embodiments, stream 205 is combined with streams 140 and 194 before being introduced into drying tower 52.

[0033] In some aspects, methods for determining the concentration of a component are disclosed.

[0034] In some embodiments, a method includes providing a system configured for contacting a first component, a second component, and a third component, wherein the system includes a reactor and a first device downstream of the reactor.

[0035] The reactor may generally include any reactor known in the art. The reactor may include one or more inlets and one or more outlets that allow the reactor to be in fluid communication with one or more other devices (e.g., the first device) of the system. The reactor may include a reservoir in which the first, second, and third components may be arranged, and the reactor may include one or more other features, including but not limited to a mixing device, a heater, etc.

[0036] The first device downstream of the reactor can include any reservoir known in the art, such as a collection reservoir configured to collect any one or more phase fluids. In some embodiments, the first device downstream of the reactor includes a flash tank. However, other first devices can be envisioned.

[0037] In some embodiments, the system further comprises a second device downstream of the reactor. Thus, in some embodiments, the methods described herein comprise providing a system configured to contact a first component, a second component, and a third component, wherein the system comprises a reactor, a first device downstream of the reactor, and a second device downstream of the reactor. The second device may be downstream of the first device, or vice versa. The second device may comprise a drying tower.

[0038] The first component, the second component and the third component can be independently selected from any reactant or non-reactant (e.g., solvent) of any known chemical process. In some embodiments, the first component is methyl acetate. In some embodiments, the second component is methyl iodide. In some embodiments, the third component is water.

[0039] In some embodiments, the methods described herein further include determining the concentration of the second component in the reactor; determining the concentration of the third component in the reactor; and determining the temperature and pressure of the first device (e.g., wherein). The temperature and pressure of the first device can be determined by any known technique and / or equipment.

[0040] The methods described herein may include determining the concentration of the second component in the reactor, and determining the concentration of the third component in the reactor. The determination of the concentrations of the second and third components may be achieved by any direct or indirect analytical technique known in the art or described herein, and the techniques for determining the concentrations may be the same or different.

[0041] In some embodiments, determining the concentration of the second component in the reactor and the concentration of the third component in the reactor includes directly determining the concentration of the second component in the reactor and the concentration of the third component. In some embodiments, determining the concentration of the second component in the reactor and the concentration of the third component in the reactor includes directly determining the concentration of the second component in the reactor and the concentration of the third component by Fourier transform infrared spectroscopy and / or Raman spectroscopy.

[0042] In some embodiments, determining the concentration of the third component in the reactor includes determining the concentration of the third component in the second device or in the feed provided to the second device; and calculating the concentration of the third component in the reactor based on (i) the concentration of the third component in the second device or (ii) the feed provided to the second device. In some embodiments, determining the concentration of the second component in the reactor includes directly determining the concentration of the second component in the reactor, for example, by Fourier transform infrared spectroscopy and / or Raman spectroscopy, and determining the concentration of the third component in the reactor includes determining the concentration of the third component in the second device or in the feed provided to the second device; and calculating the concentration of the third component in the reactor based on (i) the concentration of the third component in the second device or (ii) the feed provided to the second device.

[0043] In some embodiments, the second device is a drying tower, and the third component is water, and the concentration of water in the drying tower or the feed provided to the drying tower is determined by Fourier transform infrared spectroscopy and / or Raman spectroscopy. The concentration of water in the drying tower or the feed provided to the drying tower can be determined according to known methods, such as those methods disclosed in U.S. Patent No. 6,552,221, which are incorporated herein by reference. The drying tower can be operated on a temperature gradient concept and includes many liquid-loaded trays. The online analysis of water in the drying tower feed and / or in these trays can provide the instantaneous and continuously updated water distribution of the tower.

[0044] In some embodiments, the second device is a drying tower, the third component is water, and determining the concentration of water in the drying tower or the feed provided to the drying tower comprises determining a light ends column (LEC) reflux ratio; and relating the concentration of water according to Equations 2a and 2b:

[0045] and

[0046]

[0047] Where: [H2O] DCf is the mass fraction of water in the drying tower or the feed provided to the drying tower; C1, C2 and C3 are the temperature distribution coefficients of the drying tower; T DCTy is the water concentration-dependent temperature of the drying tower reactor at disk y; P DCovr is the drying tower operating pressure; dP DC is the total pressure drop of the drying tower from all trays; C4, C5 and C6 are the mass transfer operating line coefficients of the drying tower; R DC is the drying tower reflux rate; D DC is the drying tower distillate rate; F DC is the drying tower feed rate; [H2O] LECTs is the water concentration of the side distillate of the light fraction tower; D HEC is the heavy fraction distillation rate; F 再运行 is the drying tower feed rate from the rerun tank; [H2O] HECd is the water concentration of the heavy fraction distillate; D HEC is the heavy fraction extraction rate; and [H2O] 再运行 Is to re-run the tank water concentration. Figure 1 The rerun tank shown as 208 in FIG. 1 is the rejected product tank from which rejected acetic acid is returned to the drying tower for reprocessing. x and y refer to the total number of drying tower trays and the trays selected for correlation, respectively.

[0048] As described in Example 2 herein, the units of measurement for all equations and expressions in the examples are mass fraction "[H2O]", degrees Fahrenheit "T", psig "P, dP" and lbs / hr "F, D, R"; wherein all constants "C" are unitless.

[0049] In some embodiments, calculating the concentration of water in the reactor based on the concentration of water in the second device or the feed provided to the second device includes solving Equation 3:

[0050]

[0051] Where: [H2O] 反应器 is the mass fraction of water in the reactor, based on the concentration of water in the second device fed thereto; R LECis the light ends column reflux rate; and D LEC is the light ends column total distillate rate, where total refers to the decanter light and heavy phases combined.

[0052] In some embodiments, the methods described herein include calculating a first concentration of a first component in a reactor based on (i) a concentration of a second component in the reactor, (ii) a concentration of a third component in the reactor, and (iii) a temperature and pressure of the first device.

[0053] As used herein, the phrase "first concentration of the first component" refers to the concentration of the first component calculated based on (i) the concentration of the second component in the reactor, (ii) the concentration of the third component in the reactor, and (iii) the temperature and pressure of the first device.

[0054] In some embodiments, the system further comprises an analyzer configured to directly measure a second concentration of the first component in the reactor. Thus, in some embodiments, the method comprises providing a system configured to contact a first component, a second component, and a third component, wherein the system comprises a reactor, an analyzer configured to directly measure a second concentration of the first component in the reactor, and a first device downstream of the reactor.

[0055] As used herein, the phrase "a second concentration of the first component in the reactor" refers to the concentration of the first component in the reactor directly measured by an analyzer.

[0056] In some embodiments, the method includes directly measuring the second concentration of the first component with an analyzer. The analyzer can directly measure the second concentration of the first component by any known analytical technique. In some embodiments, the analyzer directly measures the second concentration of the first component by Fourier transform infrared spectroscopy and / or Raman spectroscopy.

[0057] The method described herein may include comparing the first concentration of the first component and the second concentration of the first component. The result of the comparison may inform further actions. In some embodiments, the method includes replacing or repairing the analyzer if the difference between the first concentration and the second concentration of the first component exceeds a predetermined threshold. The predetermined threshold may, for example, include a percentage (e.g., 0.01% to 20%, 0.01% to 15%, 0.01% to 10%, 0.01% to 5%, 0.01% to 1%, etc.) or a numerical value (e.g., within 20 units, 15 units, 10 units, 5 units, 1 unit, etc.). For example, if the predetermined threshold is 10%, then if the first concentration (as any example) is 30 units and the second concentration is not within the range of 27 units to 33 units, or in other words, 30 units ± 10%, then the analyzer may be replaced or repaired.

[0058] In some embodiments, the first component is methyl acetate, the second component is methyl iodide, the third component is water, the first device is a flash tank, and calculating the first concentration of the first component in the reactor includes solving Equation 1:

[0059]

[0060] Where: [MeAc]reactor is the reactor MeAc concentration; T 闪蒸罐 is the flash tank temperature; C w is the reactor water coefficient; [H2O] 反应器 is the H2O concentration in the reactor; C m is the reactor MeI coefficient; [MeI] 反应器 is the reactor MeI concentration; C p is the flash tank operating pressure coefficient; P 闪蒸罐 is the flash tank pressure; and C a is the flash tank temperature coefficient.

[0061] As described in Example 1, the units of measurement in Equation 1 are mass fraction of the total reactor composition, degrees Fahrenheit, and psig; and all constants "C" are unitless. Those skilled in the art will recognize that the values ​​of the coefficients (otherwise referred to as constants) will vary from manufacturer to manufacturer and will be specific to variables including, but not limited to, distillation train design and reactor chemistry.

[0062] In some embodiments, the method includes providing a system configured for contacting a first component, a second component, and a third component, wherein the system includes a reactor and a first device downstream of the reactor, and determining a first concentration of the first component in the reactor based on (i) the concentration of the second component in the reactor, (ii) the concentration of the third component in the reactor, and (iii) the temperature and pressure of the first device.

[0063] In some embodiments, the methods of the present disclosure may be performed by a computing system. Figure 2 An example of system 240 is shown that may include one or more computing systems 241-1, 241-2, 241-3, and 241-4, which may be operatively coupled via one or more networks 249, which may include wired and / or wireless networks.

[0064] As an example, a system may include a single computer system or an arrangement of distributed computer systems. Figure 2In the example of , the computer system 241-1 may include one or more modules 242, which may be or include processor executable instructions, such as executable to perform various tasks (e.g., receive information, request information, process information, simulate, output information, etc.). For example, the execution of these instructions may cause the processor to implement one or more parts and / or embodiments of the above-mentioned methods.

[0065] As an example, the modules may be executed independently or in coordination with one or more processors 244, which may be operably coupled to one or more storage media 246 (e.g., via wire, wireless, etc.). As an example, one or more of the one or more processors 244 may be operably coupled to at least one of the one or more network interfaces 247. In such an example, the computer system 241-1 may, for example, send and / or receive information via one or more networks 249 (e.g., consider one or more of the Internet, a private network, a cellular network, a satellite network, etc.).

[0066] As an example, computer system 241-1 can receive information from and / or send information to one or more other devices, which can be or include, for example, one or more computer systems 241-2, etc. The device can be located in a physical location different from computer system 241-1. As an example, the location can be, for example, a processing facility location, a data center location (e.g., a server farm, etc.), a chemical facility, a reactor, a flash tank, a light fraction column, a heavy fraction column, a drying column, etc. As an example, the device can be, for example, a temperature sensor, a pressure sensor, a spectrometer, a Fourier transform infrared spectrometer, a Raman spectrometer, etc.

[0067] As examples, a processor may be or include a microprocessor, a microcontroller, a processor module or subsystem, a programmable integrated circuit, a programmable gate array, or another control or computing device.

[0068] As an example, storage media 246 can be implemented as one or more computer-readable or machine-readable storage media. As an example, storage can be distributed within and / or on multiple internal and / or external enclosures of the computing system and / or additional computing systems.

[0069] As examples, the one or more storage media may include one or more different forms of memory, including semiconductor memory devices such as dynamic or static random access memory (DRAM or SRAM), erasable and programmable read-only memory (EPROM), electrically erasable and programmable read-only memory (EEPROM) and flash memory, magnetic disks such as fixed disks, floppy disks and removable disks, other magnetic media including magnetic tapes, optical media such as compact disks (CDs) or digital video disks (DVDs), disk, or other type of optical storage device, or other type of storage device.

[0070] As an example, one or more storage media may be located in the machine running the machine-readable instructions, or located at a remote site from which the machine-readable instructions may be downloaded over a network for execution.

[0071] As an example, various elements of a system such as a computer system may be implemented in hardware, software, or a combination of hardware and software (eg, including firmware), including one or more signal processing and / or application specific integrated circuits.

[0072] As an example, a system may include a processing device, which may be or include a general purpose processor or a dedicated chip (eg, or chipset) such as an ASIC, FPGA, PLD, or other suitable device.

[0073] Figure 3 Elements of a computing system 300 and a networking system 310 are shown. System 300 includes one or more processors 302, memory and / or storage elements 304, one or more input and / or output devices 306, and bus 308. In an exemplary embodiment, instructions may be stored in one or more computer-readable media (e.g., memory / storage elements 304). Such instructions may be read by one or more processors (e.g., processor 302) via a communication bus (e.g., bus 308), which may be wired or wireless. One or more processors may execute such instructions to implement (all or part of) one or more properties (e.g., as part of a method). A user may view output from a process and interact with the process via an I / O device (e.g., device 306). In an exemplary embodiment, a computer-readable medium may be a storage element such as a physical memory storage device, such as a chip, a chip on a package, a memory card, etc. (e.g., a computer-readable storage medium).

[0074] In an exemplary embodiment, the elements can be distributed, such as in a network system 310. The network system 310 includes elements 322-1, 322-2, 322-3. .. 322-N. For example, element 322-1 may include a processor 302, and element 322-3 may include a memory accessible by processor 302. In addition, element 322-2 may include an I / O device for displaying and optionally interacting with the method. For example, one or more of element 322-N may also include, for example, a temperature sensor, a pressure sensor, a spectrometer, a Fourier transform infrared spectrometer, a Raman spectrometer, etc. For example, if the difference between the first concentration and the second concentration of the first component exceeds a predetermined threshold, the I / O device may receive and display an alarm. The alarm may indicate that the analyzer needs maintenance or replacement.

[0075] As an example, an I / O device may be a mobile device that includes one or more network interfaces for information communication. For example, a mobile device may include a wireless network interface (e.g., via IEEE 802.11, ETSI GSM, As an example, a mobile device may include components such as a main processor, a memory, a display, a display graphics circuit (e.g., optionally including touch and gesture circuits), a SIM slot, audio / video circuits, motion processing circuits (e.g., accelerometers, gyroscopes), wireless LAN circuits, smart card circuits, transmitter circuits, GPS circuits, and batteries. As an example, a mobile device may be configured as a cellular phone, a tablet, etc. As an example, a method may be implemented (e.g., in whole or in part) using a mobile device. As an example, a system may include one or more mobile devices.

[0076] As an example, the system can be a distributed environment, such as a so-called "cloud" environment, where various devices, elements, etc. interact for the purpose of data storage, communication, computing, etc. As an example, a device or system can include one or more elements for communicating information via one or more Internets (e.g., where communication occurs via one or more Internet protocols), cellular networks, satellite networks, etc. As an example, the method can be implemented in a distributed environment (e.g., in whole or in part as a cloud-based service).

[0077] As an example, information can be input from a display (e.g., consider a touch screen), output to a display, or both. For example, the information can be output to a projector, laser device, printer, etc. so that the information can be viewed.

[0078] The terms "a", "an", and "the" are intended to include multiple alternatives, such as at least one. For example, unless otherwise specified, disclosure of "reactor", "device", etc. is intended to include a mixture or combination of one or more than one reactor, device, etc.

[0079] In the description provided herein, the terms "comprising," "is," "containing," "having," and "including" are used in an open-ended manner and should therefore be interpreted to mean "including but not limited to." When a method or system is claimed or described in terms of "comprising" various components or steps, the method or system may also "consist essentially of" or "consist of" the various components or steps, unless otherwise stated.

[0080] Various numerical ranges may be disclosed herein. When the applicant discloses or claims any type of range, the applicant's intention is to disclose or claim individually every possible number that such a range may reasonably encompass, including the endpoints of the range and any subranges and combinations of subranges encompassed therein, unless otherwise indicated. In addition, the numerical endpoints of the ranges disclosed herein are approximate.

[0081] Throughout this application, the term "about" is used to indicate that a value includes variations in error, such as for equipment, methods for determining a value, or variations that exist among research subjects. The term "about" is used to imply natural variations in conditions and indicates a variation of plus or minus 5% of a value. In some embodiments, the variation is plus or minus 1% of a value.

[0082] The processes described herein may be performed or executed in any order desired in various implementations. In addition, in some implementations, at least a portion of the processes may be performed in parallel. In addition, in some implementations, less than or more than the described processes may be performed.

[0083] Although the disclosed processes and systems have been described in detail, it should be understood that various changes, substitutions and modifications may be made herein without departing from the spirit and scope of the invention as defined by the appended claims. In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, compositions, devices, methods and / or steps described in the specification. As will be readily understood by those of ordinary skill in the art from this disclosure, according to the present invention, processes, machines, compositions, devices, methods and / or steps that currently exist or will be developed later that perform substantially the same functions as the corresponding embodiments described herein or achieve substantially the same results may be utilized. Therefore, the appended claims are intended to include such processes, machines, compositions, means, methods and / or steps within their scope.

[0084] Examples

[0085] The present disclosure is further illustrated by the following examples, which are not to be construed in any way as limiting its scope. On the contrary, it should be understood that, after reading the specification herein, various other aspects, embodiments, modifications and equivalents thereof may be conceived by those of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the appended claims. Therefore, other aspects will be apparent to those skilled in the art, taking into account the specification and practice of the subject matter disclosed herein.

[0086] Example 1 - Methyl acetate measurement

[0087] In the examples, the methyl acetate concentration was measured in a reactor containing methyl acetate, methyl iodide, and water.

[0088] Since the example methyl acetate calculation requires real-time reactor methyl iodide and water values, reasonably accurate values ​​for these two components can be obtained from spectroscopic data, but other techniques may be used.

[0089] Reactor methyl iodide has a strong, well-resolved Raman peak, while water has a partially overlapping Raman peak.

[0090] In the method of the examples, a combination of Raman methyl iodide and water values ​​and flash tank temperature and pressure values ​​are used to calculate the reactor methyl acetate concentration during the time period in which the feed rate reduction occurs.

[0091] exist Figure 4 In the graph of , the calculated values ​​for the example are overlaid with the Raman measured values. The trend line labeled FT-Raman includes the calculated values ​​for methyl acetate, while the trend line labeled Raman includes the Raman measured values ​​for methyl acetate.

[0092] Figure 4 This indicates that there is a strong correlation between the trends. The calculated methyl acetate concentration is noisier (ie, slightly less accurate) than the Raman measured trend, the source of the noise being the Raman water measurement, which is factored into the calculation of methyl acetate.

[0093] However, the data demonstrate the usefulness of the calculated methyl acetate trend as a cross-check of the Raman data or as a primary source of methyl acetate data when, for example, the Raman analyzer is down.

[0094] Equation 1 below provides the methyl acetate calculation used in the examples:

[0095]

[0096] The units of measurement in Equation 1 are mass fraction of the total reactor composition, degrees Fahrenheit and psig; all constants "C" are unitless. The correlation is based on the fact that the adiabatic flash major component composition is strictly dependent on temperature and pressure.

[0097] Example 2 - Using Drying Tower Feed (DCF) H2O Measurement Data

[0098] The method of Example 1 can be performed in an alternative manner, as explained in the Examples. Instead of using Raman reactor water data, drying tower feed water data can be used to infer reactor water composition. Drying tower feed water data can be obtained from (i) correlation using process data from a drying tower, or (ii) a near infrared (e.g., NIR FTIR) analyzer (when available).

[0099] The drying column water concentration may be strongly correlated to the reactor water concentration (with an offset), where the only contributing variable may be the light ends column reflux ratio, which may be a key equipment independent variable.

[0100] In the example, the drying tower feed water composition is related using Equations 2a and 2b as follows:

[0101] and

[0102]

[0103] For example, the conceptual correlation from drying tower feed water to reactor water is depicted in Equation 3 below:

[0104]

[0105] The units of measurement for all equations and expressions in this example are mass fraction "[H2O]", degrees Fahrenheit "T", psig "P, dP", and lbs / hr "F, D, R"; all constants "C" are unitless.

[0106] The basis for the water correlation of the examples is the gas-liquid balance of the temperature-compensated water-acetic acid system from the pressure inside the separation device, which is then adjusted based on changes in the mass balance of the separation unit.

[0107] When the reactor water value obtained from the drying tower feed correlation (Equations 2a, 2b, and 3) is used for the reactor methyl acetate calculation, the calculated methyl acetate trend line has significantly less noise ( Figure 5 ). Figure 5 The Raman reactor methyl acetate data are depicted overlaid with the reactor methyl acetate predicted by correlation, with Raman methyl iodide and correlated water as inputs.

[0108] Drying tower feed water data can also be measured in real time with a NIR-FTIR analyzer. Unlike partially resolved peaks in Raman, water has several fully resolved peaks in NIR. Therefore, NIR water and related data have the benefit of improved accuracy based on fully resolved FTIR peaks and lack of noise from temperature and pressure instruments, respectively.

[0109] The particular embodiments disclosed above are illustrative only, as those skilled in the art may modify and practice the processes and systems in different but equivalent manners with the benefit of the teachings herein. In the event of a conflict between one or more incorporated patents or publications and the present disclosure, the present specification (including definitions) will control. Furthermore, no limitation is intended to the details of construction or design shown herein, except as described in the claims below. Therefore, it is evident that the particular embodiments disclosed above may be changed or modified, and all such variations are considered to be within the scope and spirit of the invention. Therefore, the protection sought herein is as described in the claims below.

Claims

1. A method for measuring the concentration of a component, the method comprising: A system configured for contacting a first component, a second component, and a third component is provided, the system comprising— Reactor, and a first device downstream of the reactor; determining a concentration of the second component in the reactor; determining the concentration of the third component in the reactor; determining the temperature and pressure of the first device; as well as A first concentration of the first component in the reactor is calculated based on (i) the concentration of the second component in the reactor, (ii) the concentration of the third component in the reactor, and (iii) the temperature and the pressure of the first device.

2. The method according to claim 1, wherein: The system also includes an analyzer configured to directly measure a second concentration of the first component in the reactor.

3. The method according to claim 2, further comprising directly measuring the second concentration of the first component by Fourier transform infrared spectroscopy and / or Raman spectroscopy with the analyzer. 4 . The method of claim 3 , further comprising generating an alarm if a difference between the first concentration and the second concentration of the first component exceeds a predetermined threshold. 5 . The method of claim 4 , further comprising replacing or repairing the analyzer if the difference between the first concentration and the second concentration of the first component exceeds a predetermined threshold.

6. The method according to claim 1, wherein: The determining the concentration of the second component in the reactor includes directly determining the concentration of the second component in the reactor by Fourier transform infrared spectroscopy and / or Raman spectroscopy.

7. The method according to claim 1, wherein: The determining of the concentration of the second component in the reactor and the concentration of the third component in the reactor includes directly determining the concentration of the second component and the concentration of the third component in the reactor by Fourier transform infrared spectroscopy and / or Raman spectroscopy.

8. The method according to claim 1, wherein: The first component is methyl acetate, the second component is methyl iodide, and the third component is water.

9. The method according to claim 1, wherein: The first device is a flash tank.

10. The method according to claim 1, wherein - The first component is methyl acetate, The second component is methyl iodide, The third component is water, The first device is a flash tank, and The calculation of the first concentration of the first component in the reactor includes solving Equation 1: in: [MeAc]reactor is the reactor MeAc concentration; T 闪蒸罐 is the flash tank temperature; C w is the reactor water coefficient; [H2O]reactor is the reactor H2O concentration; C m is the reactor MeI coefficient; [MeI] 反应器 is the reactor MeI concentration; C p is the flash tank operating pressure coefficient; P 闪蒸罐 is the flash tank pressure; and C a is the flash tank temperature coefficient.

11. The method according to claim 1, wherein: The system also includes a second device downstream of the reactor.

12. The method according to claim 11, wherein: Determining the concentration of the third component in the reactor comprises- determining a concentration of the third component in the second device or in a feed provided to the second device; as well as The concentration of the third component in the reactor is calculated based on (i) the concentration of the third component in the second device or (ii) the feed provided to the second device.

13. The method according to claim 12, wherein: The second device is a drying tower, and the third component is water.

14. The method according to claim 13, wherein: The determining the concentration of water in the drying tower or the feed provided to the drying tower comprises determining the concentration of water by Fourier transform infrared spectroscopy and / or Raman spectroscopy.

15. The method according to claim 13, wherein: The determining the concentration of water in the drying tower or the feed provided to the drying tower comprises- Determining the light ends column (LEC) reflux ratio; and The concentrations of water are related according to equations 2a and 2b: Where: [H2O] DCf is the mass fraction of water in the drying tower or the feed provided to the drying tower; C1, C2 and C3 are the temperature distribution coefficients of the drying tower; T DCTy is the water concentration-dependent temperature of the drying tower reactor at disk y; P DCovr is the drying tower operating pressure; dP DC is the total pressure drop of the drying tower from all trays; C4, C5 and C6 are the mass transfer operating line coefficients of the drying tower; R DC is the drying tower reflux rate; D DC is the drying tower distillate rate; F DC is the drying tower feed rate; [H2O] LECTs is the water concentration of the side distillate of the light fraction tower; D HEC is the heavy fraction distillation rate; F 再运行 is the drying tower feed rate from the rerun tank; [H2O] HECd is the water concentration of the heavy fraction distillate; D HEC is the heavy fraction extraction rate; and [H2O] 再运行 Is to re-run the tank water concentration.

16. The method according to claim 15, wherein: Calculating the concentration of water in the reactor based on the concentration of the water in the second device or the feed provided to the second device includes solving Equation 3: Where: [H2O] 反应器 is the mass fraction of water in the reactor, based on the concentration of water in the second device fed thereto; [H2O] LECTs is the water concentration in the side fraction of the light fraction tower; R LEC is the light ends column reflux rate; and D LEC is the light ends column total distillate rate, where total refers to the decanter light and heavy phases combined.

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