Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Automatic analytical monitor and control of industrial process
Reexamination Certificate
1999-04-01
2001-09-04
Warden, Jill (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Automatic analytical monitor and control of industrial process
C436S055000, C436S052000, C422S116000, C422S082000
Reexamination Certificate
active
06284196
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to identification and quantification of a plurality of components in the effluent of an ammoxidation reactor by means of Fourier Transform infrared (FT-IR) spectroscopy and use of the information thus obtained to provide control and optimization of the ammoxidation reaction.
BACKGROUND OF THE INVENTION
The present invention finds significant use in the ammoxidation of both propylene and propane to produce acrylonitrile, and in general in the ammoxidation of olefins, paraffins and other starting materials to produce the corresponding nitrites. This reaction is well known and is described, for example, in U.S. Pat. No. 3,642,930 (olefins) or U.S. Pat. No. 4,897,504 (paraffins), the disclosures of which are incorporated herein by reference. In general, the ammoxidation reaction is accomplished by contacting the reactant olefin or paraffin (or other starting material), oxygen and ammonia, in the vapor phase, with a particular ammoxidation catalyst, at an elevated temperature and at atmospheric or near atmospheric pressure. The reaction may be carried out in the same manner and under the conditions generally set forth, for example, in the '930 patent or the '504 patent.
In addition to olefins and paraffins, oxygenated hydrocarbons can be ammoxidized with the known ammoxidation catalysts. For example, alcohols such as isopropanol, n-propanol, t-butyl alcohol, and aldehydes such as acrolein and methacrolein can be readily converted to nitriles. In general, the starting materials are olefins, paraffins, aldehydes and alcohols containing three or four carbon atoms. The general ammoxidation process for converting olefins, alcohols and aldehydes to the corresponding nitriles is well known and described for example in U.S. Pat. Nos. 3,642,930 and 4,897,504, and others assigned to The Standard Oil Company.
The following description of the ammoxidation reaction, both in the background and in the description of the invention, may use an olefin, sometimes specifically propylene, for exemplary purposes. The invention is not so limited and is applicable to ammoxidation reactions using any known starting material and particularly including paraffins in addition to olefins. It is further noted that, as would be understood by a person of skill in the art, it may be necessary to adjust the process, including changing catalysts used, according to the particular starting material employed and according to the products desired to be produced. For convenience herein, the term “hydrocarbon” may be employed for referring to the organic feed material, be it olefin, paraffin or other known ammoxidation feed material.
In monitoring and controlling the ammoxidation reaction, it has heretofore been the practice in the industry to operate the reactor based on test results obtained from previous operations of the reactor, where the test results are obtained from quality control procedures known as “recovery runs”. Recovery runs are laboratory chemical analyses performed on collected samples of the effluent stream and/or collected products of the ammoxidation reaction (i.e., a day's production). Recovery runs require a minimum of several hours to perform, so cannot provide contemporaneous, real-time information as to the ammoxidation reaction. For these reasons, recovery runs can only provide hindsight information as to the parameters of operation of the ammoxidation reaction. The industry has long sought both more rapid analysis of the reaction products and a way to provide such information in real time, so as to allow the control and optimization of the ammoxidation reaction during the course of a reaction, i.e., in “real-time”.
SUMMARY OF THE INVENTION
In one embodiment, the present invention is an apparatus for identifying and quantifying components in an effluent stream from an ammoxidation reactor, comprising a microprocessor; and a FT-IR spectrometer having a sample cell through which may flow a portion of the effluent stream, an infrared source to emit infrared radiation and pass the infrared radiation through the effluent stream, an infrared detector to detect transmitted infrared radiation at selected infrared wavelengths and to generate absorbance data due to absorbance of the infrared radiation by the components, wherein each of the components absorbs infrared radiation at one or more of the infrared wavelengths, and an output apparatus to provide the absorbance data to the microprocessor; wherein the microprocessor is programmed to identify and quantify each of the plurality of components based upon the absorbance data and calibration data, the calibration data being obtained from recovery run analyses and FT-IR calibration analyses in the sample cell.
In one embodiment, the invention is a method for identifying and quantifying components in an effluent stream from an ammoxidation reactor, comprising (A) advancing a portion of the effluent stream through a sample cell in a FT-IR spectrometer; (B) scanning the portion in the sample cell with infrared energy at a plurality of infrared wavelengths, wherein each of the components absorbs the infrared energy at one or more of the plurality of selected wavelengths; (C) detecting the infrared radiation passing through the sample cell and generating absorbance data for each of the components; and (D) quantifying each of the components by comparing the absorbance data to a calibration curve for each component in a microprocessor programmed to quantify each of the components.
In one embodiment, the invention is a method for controlling operation of an ammoxidation reactor based upon real-time quantitative analysis of components in an effluent stream from the ammoxidation reactor, comprising (a) preparing a calibration curve for each of the components by analyzing a plurality of effluent streams each containing the plurality of components by a calibration process comprising: (a-1) advancing at least a portion of each effluent stream through a sample cell in a FT-IR spectrometer; (a-2) scanning the effluent stream advancing through the sample cell with infrared energy across a range of infrared wavelengths and obtaining absorbance data at selected wavelengths across the range of infrared wavelengths; (a-3) collecting at least one sample corresponding to each effluent stream; (a-4) performing a recovery run analysis on the at least one sample to obtain quantitative data for each of the components in each sample; and (a-5) determining the calibration curve for each of the components by correlating the absorbance data and the quantitative data; (b) obtaining real-time absorbance data for each of the components in an operational effluent from the ammoxidation reactor by performing steps (a-1) and (a-2) thereon and calculating in a microprocessor programmed therefor real-time quantitative data for the operational effluent from the calibration curve and the real-time absorbance data; and (c) controlling the ammoxidation reactor to optimize production of at least one of the components based on the real-time quantitative data.
In one embodiment, the ammoxidation reactor is operated so as to produce acrylonitrile. In one embodiment, the acrylonitrile is produced from a propylene feed. In one embodiment, the acrylonitrile is produced from a propane feed. While the following description particularly describes the invention as applied to an acrylonitrile reactor, it is to be understood that this is for illustrative purposes only, and the invention, applicable broadly to ammoxidation reactors, is not so limited.
Thus, the present invention provides the real-time information needed to allow improved control and immediate, on-going optimization of the reaction in an ammoxidation reactor during occurrence of the reaction for which the information is obtained, thus providing the long sought “real-time” analyses and process control.
REFERENCES:
patent: 2904580 (1959-09-01), Idol, Jr.
patent: 3642930 (1972-02-01), Grasselli et al.
patent: 3936360 (1976-02-01), Chih Wu
patent: 3961896 (1976-06-01), Du
Asker Nazaneen
Baldwin Jean A.
Casal Hector L.
Nero Linda L.
Seely Michael J.
BP Corporation North America Inc.
Kim Patrick J.
Nemo Thomas E.
Sines Brian
Warden Jill
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