Patent Application
20220317103
The present disclosure relates to oxy-pyrohydrolysis reactors with protected inserts. Methods for total halogen analysis, in particular, for fluorine content analysis, in various samples using such reactors are also described.
Briefly, in one aspect, the present disclosure provides an oxy-pyrohydrolysis reactor comprising: a pyrotube comprising a combustion chamber positioned between a first end and a second end the pyrotube; and a sample insert connected to the first end of the pyrotube. The sample insert comprises a sample insert tube that extends through the first end of the pyrotube such that it is located within the combustion chamber of the pyrotube a first distance X1 from the first end of the pyrotube, and the outer opening is located outside the pyrotube; and a protective tube connected to the sample insert tube extending a second distance X2 from the first end of the pyrotube into the combustion chamber of the pyrotube, wherein the ratio of X2 over X1 is at least 2. The sample insert tube comprises a first material selected from quartz, glass, and combinations thereof; and the protective tube comprises a second material selected from a ceramic, a metal, a metal alloy, and combinations thereof.
In another aspect, the present disclosure provides combustion systems including such oxy-pyrohydrolysis reactors.
In yet another aspect, the present disclosure provides methods using of such oxy-pyrohydrolysis reactors and systems. Such methods comprise delivering, via a sample insert, a sample into a pyrotube from a first end thereof, the sample containing one or more halogen elements; and combusting the sample inside the pyrotube to produce combustion products. In some embodiments, the methods further include analyzing the combustion products to determine the total halogen (e.g., fluorine) content of the sample.
Further details of other aspects and various embodiments of this disclosure are also set forth in the description below. Other features, objects, and advantages of the invention will be apparent from the description and from the claims.
Commercial analytical combustion systems are available and can be selected to target for halogens. Generally, samples containing halogens are combusted inside a pyrotube placed inside a furnace. Combustion products (e.g., gases) can be analyzed to determine the total content of one or more halogens in the samples. Various analytical techniques for determining element contents in samples are described in, for example, U.S. Pat. Nos. 4,401,763 and 4,285,699.
Improved systems and techniques are disclosed in International Patent Publication WO 2017/172390 A1 (“Oxy-Pyrohydrolysis System and Method for Total Halogen Analysis,” P. Vorarath). Those devices included a combustion-enhancing bed including ceramic fiber or fabrics disposed inside the pyrotube to enhance the combustion and protect the pyrotube from damage by corrosive gases.
Despite the advantages of those devices, the present inventors discovered additional improvements to oxy-pyrohydrolysis systems that may further increase the reliability of total halogen analysis and extend the life of critical components such as the pyrotube.
For example, although the ceramic fibers or fabrics protected portions of the pyrotube previously known to be affected by corrosion, the enhanced combustion and the associated increase in HF concentration introduced new regions of corrosion that may limit the life of such systems. Also, although the systems of WO 2017/172390 A1 could be used with a wide variety of samples, many desirable samples (e.g., blood, soil, and seawater) contain salts, minerals and other contaminants. The presence of these materials in combination with the enhanced combustion can further contribute to increased corrosion. In addition, as the pyrotubes and other components are typically made of quartz, corrosion or etching of these parts by HF or salts can release fluorine from the quartz itself, introducing an error in the measured concentrations. This may not be a significant source of error when high concentrations of halogens are present in the samples themselves but can be a problem when attempting to accurately measure lower concentrations, e.g., less than 500 ppm, less than 250 ppm, or even less than 100 ppm.
The oxy-pyrohydrolysis reactor is placed inside furnace 170, which operates at high temperatures (e.g., 1000° C. to 1100° C.). Combustion ingredients (e.g., oxygen and/or water) can be provided into oxy-pyrohydrolysis reactor 110 to assist in burning the test samples at high temperatures. Under such oxy-pyrohydrolysis conditions (e.g., water, oxygen, heat, etc.), halogen elements (e.g., chlorine, bromine, fluorine, etc.) contained in the test sample can be converted into combustion products including gaseous compounds such as, for example, fluorides. In some embodiments, the combustion products can be trapped in a condensed steam or buffer inside condenser 120.
An analyzer can be functionally connected to the furnace, e.g., through the condenser, and configured to analyze the composition of the combustion products. In some embodiments, liquid water containing halogen ions (e.g., fluoride ions) can be separated from gases at condenser 120 before it gets transferred, via pump 104, to analyzer 106 where the total content of halogen elements (e.g., fluorine) can be analyzed. Suitable analyzers are known in the field and commercially available including, e.g., a fluoride meter module comprising, e.g., an anion chromatograph or an ion selective electrode. In some embodiments, system 100 can analyze the total fluorine content in a sample that is in the range, e.g., from about 0.005 wt % to about 35 wt %.
In some embodiments, combustion-enhancing bed 50 is provided inside oxy-pyrohydrolysis reactor 110. The combustion-enhancing bed includes ceramic fibers or fabrics which can effectively enhance the combustion of samples inside reactor 110.
Fluid inlets 42 and 46 are located near first end 22 of pyrotube 20 and configured to direct combustion ingredients such as, for example, oxygen and water into the body of the pyrotube. It is to be understood that one or more of the combustion ingredients may be optional. For example, for testing liquid samples, additional water may not be needed.
Sample insert 30 extends between first end 32 and second end 34 thereof and is connected to first end 22 of the pyrotube 20 at a junction 36. In some embodiments, the sample insert is a separate component connected to the pyrotube. In some embodiments, the sample insert can be an integral portion of the pyrotube. In some embodiments, the sample insert may have respective desirable structures according to the different type of samples (e.g., solids, liquids, emulsions, gases, etc.) to be delivered. For example, second end 34 may be configured to hold samples comprising a solid, a liquid, an emulsion, or a combination thereof. Alternatively, second end 34 may be configured to deliver fluid samples, e.g., liquids or gases.
In the depicted embodiment of
In some embodiments, the ceramic fibers can include, for example, alumina-based inorganic oxide fibers. The alumina-based inorganic oxide fibers typically have an average effective fiber diameter of at least about 5 micrometers, although this is not a requirement. In some embodiments, the average effective fiber diameter is less than or equal to 50 micrometers or less than or equal to 25 micrometers.
Useful alumina-based inorganic oxide fibers include, for example, aluminoborosilicate fibers as described in U.S. Pat. No. 3,795,524 (Sowman). In some embodiments, the aluminoborosilicate fibers comprise, on a theoretical oxide basis: about 35 percent by weight to about 75 percent by weight (more preferably, about 55 percent by weight to about 75 percent by weight) of Al2O3; greater than 0 percent by weight (more preferably, at least about 15 percent by weight) and less than about 50 percent by weight (more preferably, less than about 45 percent, and most preferably, less than about 40 percent) of SiO2; and greater than about 1 percent by weight (more preferably, less than about 25 percent by weight, even more preferably, about 1 percent by weight to about 20 percent by weight, and most preferably, about 2 percent by weight to about 15 percent by weight) of B2O3, based on the total weight of the aluminoborosilicate fibers. Preferred aluminoborosilicate fibers are commercially available as NEXTEL 312 inorganic oxide fiber from 3M Company, Maplewood, Minn.
Useful alumina-based inorganic oxide fibers also include aluminosilicate fibers. Aluminosilicate fibers, which are typically crystalline, comprise aluminum oxide in the range from about 67 to about 97 percent by weight and silicon oxide in the range from about 3 to about 33 percent by weight. Aluminosilicate fibers can be made as disclosed, for example, in U.S. Pat. No. 4,047,965 (Karst et al.). In some embodiments, the aluminosilicate fibers include, on a theoretical oxide basis, from about 67 to about 85 percent by weight of Al2O3 and from about 33 to about 15 percent by weight of SiO2, based on the total weight of the aluminosilicate fibers. In some embodiments, the aluminosilicate fibers include, on a theoretical oxide basis, from about 67 to about 77 percent by weight of Al2O3 and from about 23 to about 33 percent by weight of SiO2, based on the total weight of the aluminosilicate fibers. In some embodiments, the aluminosilicate fiber includes, on a theoretical oxide basis, from about 85 to about 97 percent by weight of Al2O3 and from about 3 to about 15 percent by weight of SiO2, based on the total weight of the aluminosilicate fibers. Aluminosilicate fibers are commercially available, for example, as NEXTEL 550 and NEXTEL 720 aluminosilicate fiber from 3M Company.
In some embodiments, the alumina fibers include, on a theoretical oxide basis, greater than about 98 percent by weight of Al2O3 and from about 0.2 to about 1.0 percent by weight of SiO2, based on the total weight of the alumina fibers. Alpha alumina fibers are available, for example, as NEXTEL 610 inorganic oxide fiber from the 3M Company.
Referring now to
Sample insert 330 further includes protective tube 360 connected to inner opening 340 of sample insert tube 305. Generally, the connection between the protective tube and the inner opening of the sample insert tube is a sealed connection to eliminate leaks. Protective tube 360 includes second end 364, serving as the inner opening of sample insert 330. Second end 364 may be configured to hold samples to be inserted into the pyrotube, e.g., samples comprising solids, liquids, emulsions and combinations thereof. Second end 364 may also be configured to deliver fluid samples, e.g., liquid or gases to the desired location in the pyrotube.
When sample insert 330 is assembled with a pyrotube, the sample insert can be connected to the pyrotube at junction 336, with sample insert tube 305 extending a distance X1 into the pyrotube. In some embodiments, it can be desirable to minimize distance X1 to limit the potential for exposure to the corrosive combustion environment.
When sample insert 330 is assembled with a pyrotube at junction 336, protective tube 360 extends a distance X2 into the combustion chamber of the pyrotube to position second end 364 at the desired location, wherein X2 is greater than X1. In some embodiments, the ratio of X2 over X1 is at least 2, e.g., at 10, at least 20, or even at least 50. In some embodiments, protective tube 360 may cover some of or all of the portion of sample insert tube 305 that extends into the combustion chamber.
Generally, insert tube 305 is made of materials that can withstand high temperatures (e.g., about 1100° C. or higher). Such materials may include, for example, quartz or glass. In some embodiments, insert tube 305 is a quartz tube. In some embodiments, the insert tube may comprise ceramics, metals (e.g., Pt), or metal alloys.
Generally, protective tube 360 is made of materials that can withstand high temperatures, but also resist damage from corrosive gases produced in the combustion process, such as, for example, hydrogen fluoride and/or salts. Without protective tube 360, the portion of insert tube 305 disposed inside a combustion chamber may suffer damage by such corrosive gases. In some embodiments, the protective tubes can withstand high temperatures (e.g., about 1000° C., about 1100° C., or even higher). In some embodiments, protective tube 360 may be made of materials having a melting point of about 1500° C. or higher and may not bend or soften at about 1000° C. to about 1100° C. or higher.
In some embodiments, the protective tube comprises a ceramic. In some embodiments, the protective tube can include one or more metals or metal alloys. In some embodiments, the protective tube can include platinum.
Referring to
Sleeve 370 can be connected to inner tube 305 and protective tube 360 by any suitable mechanisms. In some embodiments, sleeve 370 can be connected to the inner tube and the protective tube by, e.g., adhesives to form the sample insert. In some embodiments, the sleeve can be connected to the inner tube and the protective tube by, e.g., a ground joint or a threaded connection. Generally, the connections provide a seal to prevent leakage.
Sleeve 370 can be made of any suitable materials that can resist the corrosion of hydrogen fluoride and/or salts. In some embodiments, sleeve 370 can be a ceramic tube. In some embodiments, the sleeve can include one or more metals or metal alloys (e.g., Pt or its alloy).
In the embodiments, of
In the depicted embodiment of
Sample insert 530 is connected to pyrotube 520 at first end 522 and configured to deliver samples into the combustion chamber 526. Sample insert 530 includes insert tube 505 connected at junction 536. As shown, outer opening 520 of insert tube 505 is positioned outside the pyrotube, while inner opening 540 extends a short distance through first end 522 into pyrotube 520. In some embodiments, insert tube 505 can be a separate part removably sealed to pyrotube 520 at the junction 536.
In some embodiments, insert tube 505 can be made of the same materials of the pyrotubes described herein. For example, both insert tube 505 and pyrotube 520 can be made of quartz or glass, which can be beneficial for forming the junction 536 to connect the parts.
Sample insert 530 further includes protective tube 560 connected to inner tube 505 at the inner opening 540 thereof. Second end 534 of protective tube 560 extends into combustion chamber 526 of the pyrotube to form the inner opening, through which samples can be delivered into the combustion chamber.
Although not shown, in some embodiments, oxy-pyrohydrolysis reactor 510 or 610 may further include a sheet of ceramic fabric disposed inside the pyrotube adjacent to the protective tube. Such a sheet of ceramic fabric can be, for example, sheet 54 of ceramic fabric or fiber disposed on a bottom of the pyrotube 20, as shown in
Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/057456 | 8/6/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62885043 | Aug 2019 | US |
