EP3607306A1

EP3607306A1 - An apparatus for homogenized mixing of gases

Info

Publication number: EP3607306A1
Application number: EP18709932.0A
Authority: EP
Inventors: Tejas Deepak DUBE; Jörg Gottschald; Erich Wombacher; Marc Winter
Original assignee: Emerson Process Management GmbH and Co OHG
Current assignee: Emerson Process Management GmbH and Co OHG
Priority date: 2017-04-06
Filing date: 2018-02-09
Publication date: 2020-02-12
Also published as: WO2018184756A1; CN110462384A

Abstract

The present disclosure relates to the field of mechanical engineering. In particular, the present disclosure relates an apparatus for homogenized mixing of gases for use with a chemiluminescent detector (CLD) comprising an outer conduit (102), an inner conduit (104), passing through said outer conduit (102), a first passage (104) defined through said inner conduit (102) for passage of one fluid of said two fluids, an inner wall (102') of said outer conduit (102) being spaced apart from an outer wall (104') of said inner conduit (104) to define a second passage (102A) for passage of the second fluid of said two fluids, said outer conduit (102) defining a bottom end (102B), said inner conduit (104) defining a first outlet (104B) recessed from said bottom end ( 102B). A reaction zone ( 106) is defined in the recess between said first outlet (104B) and bottom end (102B) for introducing the two fluids from said first passage (104A) and said second passage (102A), for homogenization. The technical advancement of the homogenizing apparatus of the present disclosure is that it facilitates homogeneous mixing of the gases and allows the mixture travel at the center of the detector of the CLD to avoid any loss of photons caused due to improper mixing, short-circuiting flow of the gases and quenching of light in the CLD.

Description

AN APPARATUS FOR HOMOGENIZED MIXING OF GASES

FIELD

The present disclosure relates to the field of gas mixers. BACKGROUND

Chemiluminescence is the phenomenon of emission of light during a chemical reaction. This phenomenon is used in detection of certain compounds in a sample gas. A chemiluminescence detector (CLD) is a device that utilizes the principle of chemiluminescence for detection and measurement of nitric oxide (NO) concentration in a sample gas. The CLD has a reaction chamber which allows nitric oxide NO in the sample gas to react with ozone (0₃) to form nitrogen dioxide in excited state (N0₂*). When NO2* returns to ground state, it emits photons. The photons produced are detected by a photo detector which is an indication of NO presence in the sample gas. A conventional CLD has separate or spaced apart gas inlets for ozone and sample gas. The sample gas and the ozone react in a reaction chamber in a chemiluminescent reaction which produces light. If the mixture of ozone and sample gas is not homogeneous, it results in less conversion of NO to NO2, thus resulting in loss of light. Also if the mixture travel is not at the center of the detector and short, it results in short-circuiting of flow and quenching of light, again resulting in loss of light. Any loss of light is not desired as it causes the photo detector to indicate incorrect values associated with the NO concentration within the sample gas. Also, if the mixture is not homogenous and centric, the measured signal from the photo detector will not be linear and will be highly dependent of the flow rate of the ozone stream. Hence, in an order to overcome the aforementioned drawbacks, there is need of an apparatus for obtaining a homogenized mixture of the sample gas and ozone, such that the chemiluminescent reaction thereof provides a correct reading of the NO concentration in the sample gas. OBJECTS

Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.

It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative. An object of the present invention is to provide an apparatus for homogenized mixing of gases, travelling at the center of the photo detector, which is to be used with a chemiluminescence detector.

Another object of the present invention is to provide an apparatus that facilitates homogeneous mixing and centric flow of the gases in the CLD to avoid any loss of photons caused due to improper mixing, short circuiting of the flow of the gases, and quenching of light in the CLD.

Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure. SUMMARY

The present disclosure envisages an apparatus for homogenizing two fluids. The apparatus comprises an outer conduit, and an inner conduit, passing through the outer conduit. A first passage is defined through the inner conduit for the passage of one fluid of the two fluids. An inner wall of the outer conduit is spaced apart from an outer wall of the inner conduit to define a second passage for the passage of the second fluid of the two fluids. The outer conduit defines a bottom end, and the inner conduit defines a first outlet recessed from the bottom end. A reaction zone is defined in the recess between the bottom end and the first outlet for introducing the two fluids from the first passage and the second passage, for homogenization.

In an embodiment, the outer conduit and the inner conduit are coaxial. In another embodiment, the first passage and the second passage are coaxial.

In another embodiment, the apparatus includes an exhaust port for exhaustion of the fluids from the reaction zone after homogenization.

In another embodiment, the inner conduit and the outer conduit are of stainless steel, and the inner wall of the outer conduit and the outer wall of the inner conduit are polished.

In another embodiment, the first outlet is positioned in proximity to a photo-detector for detecting photons produced in the reaction zone by the reaction of a sample fluid containing nitrous oxide passing through the first passage and ozone passing through the second passage.

The present disclosure also envisages a process of homogenizing two fluids. The process involves introducing the two fluids into a reaction zone formed by recessing an outlet of an inner conduit, through which one of the two fluids is introduced into the reaction zone, from an outer conduit through which the inner conduit is made to traverse, the second fluid of the two fluids being led, into the reaction zone, through an annular space between an outer wall of the inner conduit and an inner wall of the outer conduit.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWING

A homogenizing apparatus of the present disclosure will now be described with the help of the non-limiting accompanying drawing, in which: Fig. 1 A illustrates a schematic view of a homogenizing apparatus being used with a photo-detector, in accordance with an embodiment of the present disclosure;

Fig. IB illustrates a schematic view of a reactor unit used in a homogenizing apparatus, in accordance with an embodiment of the present disclosure; Fig. 2 illustrates a graph depicting variation of sensor output of the chemiluminescence detector corresponding to varying ozone flow rate; and

Fig. 3A and Fig. 3B illustrate a graph depicting the variation of the photo-detector output for various mass flow rates of the sample gas and air/ozone.

DETAILED DESCRIPTION An application of the chemiluminescence detector (CLD) is measuring NO concentration in a gas. The CLD has a reaction chamber which allows nitric oxide (NO) in the sample gas to react with ozone (0₃) to form nitrogen dioxide in excited state (N0₂*). When NO2* returns to ground state, it emits photons. These photons produced are detected by the photo detector which gives an indication of the NO content present in the sample gas.

The conventional CLD has separate gas inlets for ozone and the sample gas. The gases enter the reaction chamber through the separated/spaced apart gas inlets and before entering the reaction chamber, they are not premixed. The sample gas and the ozone react in the reaction chamber, thereby producing nitrogen dioxide in excited state (N0₂*). When NO2* returns to ground state, it emits photons. This light producing reaction is very rapid. If the mixture of ozone and sample gas is not homogeneous, it results in an incomplete chemiluminescent reaction resulting in less conversion of NO to NO2, thus resulting in the loss of light. Also, if the mixture travel is not at the center of the detector, it results in short-circuiting of the flow and quenching of light again resulting in loss of light. Any loss of light is not desired as it causes the photo detector to give an incorrect indication of the NO content present in the sample gas, and the measured NO-signal from the CLD will not be linear. To have a linear output signal, the reaction of the NO with the O3 has to have a complete conversation rate.

To this end, the present disclosure envisages a homogenizing apparatus for use with a CLD which facilitates the formation of homogeneous mixture of the sample gas and ozone traveling at the center of the detector and avoids loss of any photon reception by the photo detector by facilitating a substantially complete chemiluminescent reaction. Using the opposed entry at the ozone inlet tube, the gas mix stays always in the center of the detector independent of the ozone flow rate. Therefore, the CLD signal is independent of the ozone flowrate, which is a major advantage over conventional CLDs.

The homogenizing apparatus 100 (hereinafter referred to as apparatus 100) for use with a CLD 100A (hereinafter also referred to as a photo-detector) is hereinafter described with reference to Fig. 1A and Fig. IB. The apparatus 100 for homogenizing two fluids, in accordance with an embodiment of the present disclosure, comprises an outer conduit 102, and an inner conduit 104, passing through the outer conduit 102. A first passage 104 A is defined through the inner conduit 104 for the passage of one fluid of the two fluids. An inner wall 102' of the outer conduit 102 is spaced apart from an outer wall 104' of the inner conduit 104 to define a second passage 102A for the passage of the second fluid of the two fluids. The outer conduit defines a bottom end 102B, and the inner conduit defines a first outlet 104B recessed from the bottom end 102B. A reaction zone 106 is defined in the recess between the bottom end 102B and the first outlet 104B for introducing the two fluids from the first passage 104A and the second passage 102A, for homogenization. In an embodiment, the outer conduit 102 and the inner conduit 104 are coaxial. In another embodiment, the first passage 104 A and the second passage 102 A are coaxial. In another embodiment, the inner conduit 104 and the outer conduit 102 are of stainless steel, and the inner wall 102' of the outer conduit 102 and the outer wall 104' of the inner conduit 104 are polished to allow smooth passage of one of the two gases therethrough. The apparatus 100 includes at least one exhaust port 108 for exhaustion of the fluids from the reaction zone 106 after homogenization. More specifically, the chemiluminescent reaction occurs within the reaction zone 106 subsequent to the homogenizing of the two gases, wherein the sample gas of which the NO content is be calculated is fed into the reaction zone 106 via the inner conduit 104, while the ozone gas required for the chemiluminescent reaction is supplied via the outer conduit 102. After the chemiluminescent reaction, the mixture of gases present in the reaction zone 106 is exhausted via the exhaust ports 108. In an embodiment, the apparatus 100 has two exhaust ports 108 configured orthogonal to a longitudinal axis of the apparatus 100.

In an embodiment, the exhaust ports 108 are configured on diametrically opposite location defined on the outer conduit and are inclined with respect to a longitudinal axis of the apparatus 100 at an angle ranging from 10° to 170°. In an embodiment, the outer conduit 102 has two inlets 110 configured at diametrically opposite locations on the outer conduit. In another embodiment, the two inlets 110 are inclined with respect to a longitudinal axis of the apparatus 100 at an angle ranging from 10° to 170°.

In an exemplary application, the bottom end 102B of the apparatus 100 is positioned in proximity to a photo-detector 200 for detecting photons produced in the reaction zone 106 by the reaction of a sample fluid containing nitric oxide, which is one of the two fluids, passing through the first passage 104A and ozone, which is the second fluid of the two fluids, passing through the second passage 102A.

In an embodiment, the outer conduit 102 defines a second outlet 102C that facilitates the introduction of the ozone gas into the reaction zone 106. The difference in the levels of the first outlet 104B and the second outlet 102C facilitates the formation of a mixing zone 112 within the outer conduit 102. The swirling motion of the ozone gas introduced into the outer conduit 102 facilitates pre-mixing of the sample gas from the inner conduit 104 and the ozone within the mixing zone. In an embodiment, the maximum distance between the level of the first outlet 104B and the second outlet 102C is 1.5 mm, i.e., the height of the mixing zone 112 is 1.5mm. In an embodiment, the minimum distance between the bottom end 102B and the second outlet 102C is 5 mm. In an embodiment, the ratio of the distance between the first outlet 104B and the bottom end 102B, and the distance between the second outlet 102C and the first outlet 104B ranges from 2 to 4.

The present disclosure also envisages a process of homogenizing two fluids. The process involves introducing the two fluids into the reaction zone 106 formed by recessing the outlet 104B of the inner conduit 104, through which one of the two fluids is introduced into the reaction zone 106, from the outer conduit 102 through which the inner conduit 104 is made to traverse. The second fluid of the two fluids is led into the reaction zone 106 through an annular space between the outer wall 104' of the inner conduit 104 and an inner wall 102' of the outer conduit 102. In an embodiment, each of the fluids of the two fluids may be a single fluid or a mixture of fluids. In another embodiment, each of the fluids is pre-pressurized before introduction into the first and second passages.

In an embodiment, the range of sample gas flow through the inner conduit 104 ranges from 40 to 180 ml/min, and the range of ozone flow through the at least one inlet 110 configured on the outer conduit 102 ranges from 400 to 1200 ml/min. This is to facilitate a substantially complete chemiluminescent reaction between the sample gas and ozone. Furthermore, equal quantities of ozone, which is the second fluid of the two fluids, are supplied to the reaction zone 106 via the two inlets 110 to facilitate the mixture of the sample gas and the ozone to travel at the center of the reaction zone 106 to facilitate the substantially complete chemiluminescent reaction and the ozone flow independency. As discussed previously, a substantially complete chemiluminescent reaction, taking place centrally over a photo-detecting element 202, prevents the loss of photons generated during the chemiluminescent reaction. Therefore, the number of photons received and detected by a photo- detecting element 202 of the photo-detector 200 is not compromised, as was the case with the conventional inlet apparatus of the photo-detectors. Since, the number of the photons detected by the photo-detecting element 202 is not compromised; the apparatus 100 of the present disclosure facilitates a provision of substantially error- free value of the NO present in the sample gas and can measure up to 10000 ppm NO.

In an embodiment, the reaction zone 106 has a tapered configuration that facilitates fitment of the apparatus 100 on a standard sized photo-detector 200, wherein the largest diameter of the reaction zone 106 at the operative bottom end is same as that of the photo-detector 200.

Fig. 2 illustrates a graph sensor output of the chemiluminescence detector corresponding to varying ozone flow rate. As seen in Fig. 2, the ozone flow is varied from lOOOml/min to 200ml/min for a stable sample gas flow of lOOml/min and 5000ppm NO. However, the variation in the flow-rate of the ozone does not have an effect on the output of the photo-detector of the chemiluminescence detector and the output signal is linear. The unstable signal of the photo-detector at an ozone flow rate lower than 400ml/min is due to the insufficient ozone concentration in the reaction chamber. It is not an indication of bad mixing.

Fig. 3A and Fig. 3B illustrate the photo-detector output for various mass flow rates of the sample gas and ozone. Fig. 3A shows the raw measurement and Fig. 3B shows the analysis and summary. This measurement shows, additionally to the measurements in Fig. 2, the ozone flow independency of the CLD signal at different sample flow rates. This shows that the gas mix of ozone and sample gas stays always in the center of the reaction zone 106, which is a major improvement to conventional photo-detectors.

TECHNICAL ADVANCES

The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a homogenizing apparatus which:

• is to be used with a chemiluminescence detector; and • facilitates homogeneous mixing of the gases at the inlet of the CLD to avoid any loss of photons caused due to improper mixing of the gases at the inlet of the CLD independent of the ozone flow rate.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application. The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary. While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.

Claims

Apparatus (100) for homogenizing two fluids comprising:

a) an outer conduit (102);

b) an inner conduit (104), passing through said outer conduit (102);

c) a first passage (104) defined through said inner conduit (102) for passage of one fluid of said two fluids;

d) an inner wall (102') of said outer conduit (102) being spaced apart from an outer wall (104') of said inner conduit (104) to define a second passage (102 A) for passage of the second fluid of said two fluids; e) said outer conduit (102) defining a bottom end (102B);

f) said inner conduit (104) defining a first outlet (104B) recessed from said bottom end (102B); and

g) a reaction zone (106) defined in the recess between said first outlet (104B) and bottom end (102B) for introducing the two fluids from said first passage (104A) and said second passage (102A), for homogenization.

Apparatus (100) as claimed in claim 1, wherein said outer conduit (102) and said inner conduit (104) are coaxial.

Apparatus (100) as claimed in claim 1, wherein said first passage (104 A) and said second passage (102A) are coaxial.

Apparatus (100) as claimed in claim 1, which includes an exhaust port (108) for exhaustion of the fluids from said reaction zone (106) after homogenization.

Apparatus (100) as claimed in claim 1, wherein said inner conduit (104) and said outer conduit (102) are of stainless steel, and said inner wall (102') of said outer conduit (102) and said outer wall (104') of said inner conduit (104) are polished.

6. Apparatus ( 100) as claimed in claim 1 , wherein said outer conduit ( 102) has two inlets (110) configured at diametrically opposite locations on said outer conduit (102).

7. Apparatus (100) as claimed in claim 6, wherein equal quantities of the second fluid are fed to said reaction zone (106) via said two inlets (110).

8. Apparatus (100) as claimed in claim 1, wherein said bottom (102B) is positioned in proximity to a photo-detector (200) for detecting photons produced in said reaction zone ( 106) by the reaction of a sample fluid containing nitrous oxide passing through the first passage (104 A) and ozone passing through the second passage (102A), said two fluids reacting in the reaction zone

(106).

9. A process of homogenizing two fluids by introducing said two fluids into a reaction zone (106) formed by recessing an outlet (104B) of an inner conduit (104), through which one of said two fluids is introduced into said reaction zone (106), from an outer conduit (102) through which said inner conduit (104) is made to traverse, the second fluid of said two fluids being led, into said reaction zone (106), through an annular space between an outer wall (104') of said inner conduit (104) and an inner wall (102') of said outer conduit(102).

10. Process as claimed in claim 9, wherein each of said fluids may be a single fluid or a mixture of fluids.

11. Process as claimed in claim 9, wherein each of said fluids is pre-pressurized before introduction into said first and second passages.