GAS SAMPLING APPARATUS FOR EXTRACTION OF GASEOUS SAMPLES

Abstract

A gas sampling apparatus including a housing having a housing wall and a housing opening. The gas sampling apparatus includes a sample system for extracting the gaseous sample, including a sample pipe having an opening enclosed by the housing wall and in fluid communication with the gaseous environment and filter means including a filter for filtering solid particles from the gaseous sample. The filter is enclosed by the housing wall and arranged at the opening. The gas sampling apparatus includes a central purge system to remove aggregates of solid particles deposited on one or more housing surfaces by a gaseous medium, wherein the central purge system includes a purge pipe including an outlet opening directed towards the housing opening and enclosed by the housing wall, wherein the sample system is arranged externally to the central purge system so that the sample pipe is separate from the purge pipe.

Claims

1. A gas sampling apparatus for extraction of a gaseous sample from a gaseous environment comprising flue gas comprising solid particles, wherein the gas sampling apparatus comprises: a housing comprising a housing wall enclosing an interior of the housing, wherein the housing wall comprises: an exterior housing surface; an interior housing surface; a rim surface connecting the exterior housing surface and the interior housing surface and enclosing a housing opening directed towards a gaseous environment during use, wherein the housing opening is configured to provide fluid communication between the gaseous environment and the interior of the housing; a sample system for extracting a gaseous sample from the gaseous environment, wherein the sample system comprises: at least one sample pipe having an opening, wherein at least the first opening is enclosed by the housing wall and is configured to be in fluid communication with the gaseous environment; and filter means comprising at least one filter for filtering a plurality of solid particles from the gaseous sample, wherein the at least one filter is enclosed by the housing wall and arranged at the opening of the at least one sample pipe, wherein the gas sampling apparatus further comprises: a central purge system configured to remove aggregates of solid particles deposited on one or more of the rim surface, the interior housing surface and the exterior housing surface by a gaseous medium, wherein the central purge system comprises at least one purge pipe comprising an first outlet opening directed towards the housing opening and enclosed by the housing wall; and wherein the sample system is arranged externally to the central purge system so that at least the one sample pipe is separate from the at least one purge pipe.

2. The gas sampling apparatus according to claim 1, wherein the opening of the sample system is radially arranged between the central purge system and the housing wall.

3. The gas sampling apparatus according to claim 1, wherein the purge pipe configured to transfer a gaseous medium, from a gas supply system to at least a part of the interior of the housing arranged adjacent to the housing opening.

4. The gas sampling apparatus according to claim 1, wherein the outlet opening of the purge pipe has an inner outlet diameter, which is between 15-35 mm.

5. The gas sampling apparatus according to claim 1, wherein the outlet opening of the purge pipe has an inner diameter, which is between 1.5-5 times larger than an inner diameter of the opening of the at least one sample pipe.

6. The gas sampling apparatus according to claim 1, further comprising a filter cleaning system for cleaning the at least one filter, wherein the filter cleaning system comprises one of more filter cleaning pipes configured to direct a gaseous medium through the at least one filter towards the gaseous environment.

7. The gas sampling apparatus according to claim 6, wherein the one or more filter cleaning pipes comprises a filter cleaning inlet opening configured to be connected with a gas source and a filter cleaning outlet opening arranged so as to face the at least one filter.

8. The gas sampling apparatus according to claim 1, wherein the at least one filter of the filter means is arranged between the opening of the at least one sample pipe and the gaseous environment present in the interior of the housing, when the gas sampling apparatus is in use.

9. The gas sampling apparatus according to claim 1, wherein the at least one filter is arranged radially between an exterior surface of the purge pipe and the housing.

10. The gas sampling apparatus according to claim 9, wherein the at least one filter and the housing opening are positioned in an open end of the housing and wherein the open end of the housing is arranged to be positioned inside the gaseous environment, during use.

11. The gas sampling apparatus according to claim 1, wherein the at least one filter is of a tubular shape and is arranged coaxially with the purge pipe.

12. The gas sampling apparatus according to claim 1, further comprising a peripheral purge system configured to clean at least a part of an exterior surface of the at least one filter, wherein the peripheral purge system comprises one or more second purge pipes enclosed by the housing and arranged externally to the sample system.

13. The gas sampling apparatus according to claim 12, wherein the one or more second purge pipes are configured to be connected to a gas supply system and to transfer a gaseous medium from the gas supply system to at least a part of the exterior surface of the at least one filter.

14. The gas sampling apparatus according to claim 13, wherein the peripheral purge system comprises distribution means comprising one or more outlet openings, wherein the distribution means is arranged for distributing a gaseous medium from the gas supply system through the one or more outlet openings towards the housing opening.

15. The gas sampling apparatus according to claim 1, wherein the central purge system and/or the filter cleaning system and/or the peripheral purge system are arranged to be operated independently from the sample system.

16. The gas sampling apparatus according to claim 1, wherein the sample system is in connection with one or more extraction means, for extraction of a gas sample through the at least one sample pipe.

17. The gas sampling apparatus according to claim 1, wherein the sample system is configured to be in connection with a gas analysis system so as to transfer the gaseous sample extracted from the gaseous environment to the gas analysis system.

18. The gas sampling apparatus according to claim 1, comprising a gas analysis system arranged in connection with the sample system and arranged to analyze a gas sample extracted from the gaseous environment.

19. The gas sampling apparatus according to claim 1, wherein the sample system comprises heating means for heating at least an interior surface of the at least one sample pipe.

20. The gas sampling apparatus according to claim 1, wherein the housing comprises cooling means for cooling a least the exterior housing surface.

21. Use of a gas sampling apparatus comprising: a housing comprising a housing wall enclosing an interior of the housing, wherein the housing wall comprises: an exterior housing surface; an interior housing surface; a rim surface connecting the exterior housing surface and the interior housing surface enclosing a housing opening directed towards a gaseous environment during use, wherein the housing opening is configured to provide fluid communication between the gaseous environment and the interior of the housing; a sample system for extracting a gaseous sample from the gaseous environment, wherein the sample system comprises: at least one sample pipe having an opening, wherein at least the opening is enclosed by the housing wall and is configured to be in fluid communication with the gaseous environment and filter means comprising at least one filter for filtering a plurality of solid particles from the gaseous sample, wherein the at least one filter is enclosed by the housing wall and arranged at the opening of the at least one sample pipe, wherein the gas sampling apparatus further comprises: a central purge system configured to remove aggregates of solid particles deposited on one or more of the rim surface, the interior housing surface and the exterior housing surface by a gaseous medium, wherein the central purge system comprises at least one purge pipe comprising an outlet opening directed towards the housing opening and enclosed by the housing wall; and wherein the sample system is arranged externally to the central purge system so that at least the one sample pipe is separate from the at least one purge pipe, wherein the use comprises: extracting a gas sample from a gaseous environment. wherein a gaseous sample is extracted from the gaseous environment through the housing opening and the first opening and thereafter through the sample pipe; and cleaning at least a part of housing by releasing a gaseous medium towards one or more of the rim surface, the interior housing surface and the exterior housing surface through at least the first purge pipe.

22. A gas sampling apparatus for extraction of a gaseous sample from a gaseous environment comprising flue gas comprising solid particles, wherein the gas sampling apparatus comprises: a housing comprising a housing wall enclosing an interior of the housing, wherein the housing wall comprises: an exterior housing surface; an interior housing surface; a rim surface connecting the exterior housing surface and the interior housing surface and enclosing a housing opening directed towards a gaseous environment during use, the housing opening is positioned in an open end of the housing, wherein the open end of the housing is arranged to be positioned inside the gaseous environment, during use, wherein the housing opening is configured to provide fluid communication between the gaseous environment and the interior of the housing; a sample system for extracting a gaseous sample from the gaseous environment, wherein the sample system comprises: at least one sample pipe having a first opening, wherein the opening is enclosed by the housing wall and is configured to be in fluid communication with the gaseous environment; and filter means comprising at least one filter for filtering a plurality of solid particles from the gaseous sample, wherein the at least one filter is enclosed by the housing wall and arranged at the opening of the at least one sample pipe and in the open end of the housing, wherein the gas sampling apparatus further comprises; a central purge system configured to remove aggregates of solid particles deposited on one or more of the rim surface, the interior housing surface and the exterior housing surface by means of a gaseous medium, wherein the central purge system comprises at least one purge pipe comprising an outlet opening directed towards the housing opening and enclosed by the housing wall; wherein the sample system is arranged externally to the central purge system so that at least the at least one sample pipe is separate from the at least one purge pipe and wherein the at least one filter is arranged radially between the housing and an exterior surface of the at least one purge pipe.

Description

DRAWING

[0105] Aspects of the present disclosure will be described in the following with reference to the figures in which:

[0106] FIG. 1a shows a cross sectional view of the gas sampling apparatus according to embodiments of the invention.

[0107] FIG. 1b shows an enlarged view of a part of the gas sampling apparatus encircled in FIG. 1a.

[0108] FIG. 2 shows a cross-sectional view of the gas sampling apparatus along the plane A-A as indicated in FIG. 1b.

DETAILED DESCRIPTION

[0109] FIG. 1a illustrates a gas sampling apparatus 1 according to embodiments of the invention, seen in a longitudinal cross-sectional view at a vertical plane including the longitudinal centreline of the first purge pipe. A part of the gas sampling apparatus 1 shown in FIG. 1a is encircled by a dashed line and FIG. 1b shows the encircled part in an enlarged view. The gas sampling apparatus 1 may be placed inside a gaseous environment from which a gas sample is to be extracted by the gas sampling apparatus 1 in such a way that at least the tip of the gas sampling apparatus 1, including the open end of the housing 2a is placed inside the gaseous environment.

[0110] The gas sampling apparatus 1 of the present examples comprises a housing 2 for protecting the elements enclosed by the housing 2 from the gaseous environment. The housing 2 is shown comprising a housing wall 3, which has an interior surface 5 facing the interior of the housing 4 enclosed by the housing wall 3 and an exterior surface 6 facing the gaseous environment. The interior 5 and the exterior surfaces 6 of the housing 2 are connected by a rim of the housing 3a at the tip of the housing 2. The rim of the housing 3a encloses a housing opening 7 placed at the end of the housing 2 extending furthest inside the gaseous environment, referred to as the open end 2a. Opposite the open end 2a is the back end of the housing 2b.

[0111] The gas sampling apparatus 1 shown in FIGS. 1a-1b further comprises a central purge system having a first purge pipe 8, which from the open end of the housing 2a is arranged at the innermost part of the interior of the housing 4, such as substantially centrally arranged within the housing 2. At the open end of the housing 2a, the first purge pipe 8 is seen having a first outlet opening 8b facing the housing opening 7. By means of a nozzle 20 arranged adjacent to the first outlet opening 8b, gaseous medium from the first gas supply system may be directed towards the entire area of the housing opening 7 and/or parts of the interior surface of the housing wall 5. The first gas supply system of the present example is shown comprising a blaster system 16 having a gas tank 16a and a canon valve 16b for supplying gas through the first purge pipe 8 as indicated by the arrows in FIGS. 1a and 1b.

[0112] The gas sampling apparatus 1 shown in FIGS. 1a-1b further comprises a peripheral purge system having a second purge pipe 12 in fluid connection with distributing means 19. The distributing means 19 are arranged to distribute the gaseous medium collected from the second purge pipe 12 through one or more second outlet openings 19a of the distributing means 19 arranged substantially along the periphery of the interior surface of the housing 5. The first purge pipe 8 has an exterior surface 9 directed towards the interior surface of the housing 5, and a space may be provided between the exterior surface of the first purge pipe 9 and the interior surface of the housing 5, which may be tubular as shown in the present examples. In the present examples, the space is also used as a filter housing 15 and the second outlet openings 19a of the peripheral purge system are located so as to introduce gaseous medium into the filter housing 15.

[0113] Towards the back end of the housing 2b, the second purge pipes 12 are connected to distributing means 19 which in turn is connected to a supply pipe connected to a second gas supply system, comprising a blaster system 18 with a canon valve 18b and a gas tank 18a. The distributing means distributes the air supplied from the gas tank 18a to the second purge pipes 12 as indicated by the arrows in FIGS. 1a-1b.

[0114] Along the pipeline from the gas tanks 16a, 18a and the first purge pipe 8 and the second purge pipe 12, a large inner diameter of the exit hole of the gas tanks 16a, 18a and any pipe sections and connections means interconnecting the gas tanks 16a, 18a to the first and second purge pipes 8, 12 are ensured so that a large volume of compressed gas may be released towards the open end of the housing 7 from the gas supply systems.

[0115] The gas sampling apparatus 1 is shown in FIGS. 1a-1b with a sample pipe 10 arranged inside the housing 2 and extending along the exterior surface of the first purge pipe 9 towards the open end of the housing 2a to a position located prior to the location of the first outlet opening 8b of the first purge pipe 8, i.e. further away from the housing opening 7 than the first outlet opening 8b. The sample pipe is arranged in connection with extraction means 22, such as a pump, for extracting a gaseous sample, such as for continuous extraction of a gas sample. The sample pipe 10 is arranged separately to the first and second purge pipes as shown in FIG. 1a, and is not physically connected with any of those pipes 8, 12 or distribution means 19, but instead functions independently from the central and peripheral purge systems of the apparatus 1. As indicated by arrows in FIG. 1b, the gas sample is directed in a direction from the open end of the housing 2a towards the back end of the housing 2b. The sample pipe 10 of the present example may be heated by heating means to a temperature which prevents condensation of water and acid from gaseous sample.

[0116] The gas sample apparatus 1 of the present examples collects gas, such as exhaust gas, through a filter 13, which is placed in the open end of the housing 2a arranged in the gaseous environment, such that the filter 13 is facing the gaseous environment. The gas sampling apparatus 1 may comprise a filter 13 of a tubular shape enclosing the first purge pipe 8 at an end of the pipe 8 and arranged in front of the first opening 10a of the sample pipe 10. The tubular filter 13 comprises and exterior surface 14a directed towards the interior surface of the housing wall 5 and an interior surface 14b directed towards the exterior surface of the first purge pipe 9, e.g. in abutment with first purge pipe 8. In one or more examples, the second outlet openings 19a are arranged to clean the exterior surface of the filter 14a exposed in the filter housing 15.

[0117] Furthermore, in one or more examples, the gas sampling apparatus 1 may comprise a filter cleaning system having one or more, such as three, filter cleaning pipes 11 arranged to provide gaseous medium to clean the filter 13 by directing the gaseous medium devoid of solid particles through the filter 13 towards the open end of the housing 2a. The filter cleaning system is shown in FIGS. 1a-1b as comprising a gas source 21a for providing the gaseous medium and a valve 21b for controlling the flow of gaseous medium. In the present examples, the filter cleaning pipe 11 comprises and outlet opening 11a arranged so as to face an end of the tubular filter 13 of the gas sampling apparatus 1, such that the filter 13 may be cleaning by blowing gaseous medium in a direction along the longitudinal extent of the filter 13. This will cause dust to be forced to the exterior surface of the filter 14a, where it can be further transported out through the housing opening 7 by at least the peripheral purge system.

[0118] In one or more examples of the present invention, the gas sampling apparatus 1 is arranged so that the flow direction of gaseous medium in the sample pipe 10 is opposite to the flow direction of the gaseous medium in the first purge pipe(s) 8, the second purge pipe(s) 12 and the filter cleaning pipe(s) 11. An example of such flow directions are indicated in FIG. 1b.

[0119] The first purge pipe 8 and the second purge pipe 12 are shown as being a straight pipes extending out through the back end of the housing 2b, and connected by connections means, e.g. a further pipe section, to a first gas supply system and second gas supply system, respectively. Similarly, the sample pipe 10 and the filter cleaning pipe 11 is also straight pipes extending through the back end of the housing 2b and connected to further pipe sections and the extractions means 22 and the gas source 21 respectively.

[0120] Alternatively, all or some of the pipes 8, 10, 11, 12 may extend a shorter distance through the housing 2 and instead be connected to further pipe sections arranged through the housing wall 3. In one or more examples, the first purge pipe 8 and/or the second purge pipe 12 and/or the sample pipe 10 and/or the filter cleaning pipe 11 may be arranged in parallel inside the housing 2.

[0121] FIG. 2 shows a schematic cross-sectional view of the gas sampling apparatus 1 in a plane extending through the filter of the gas sampling apparatus 1, wherein the plane is perpendicular to the longitudinal extent of the first purge pipe 8. In the present example, the gas sampling apparatus comprises several layers of pipes for different purposes. The layers are as arranged from the centre of the gas sampling apparatus to the perimeter of the gas sampling apparatus 1. The first purge pipe 8 of the central purge system is located in the center-most position and provides the center about which the further layers are arranged.

[0122] In one or more examples, the filter cleaning pipe(s) 11 and the sample pipe(s) 10 are located in a layer immediately adjacent to the first purge pipe 8. They may be arranged with a distance corresponding to the arc provided by a 120 angle between neighbouring filter cleaning pipe(s) 11 and/or sample pipe(s) 10. In the present example, the gas sampling apparatus 1 comprises two filter cleaning pipes 11 and one sample pipe 10. Each sample pipe 10 comprises a first opening of the sample pipe 10a and each filter cleaning pipe 11 comprises a filter cleaning outlet opening 11a directed towards the open end of the housing 2 comprising the housing opening. The filter 13 is arranged as a part of the same layer as the sample pipe 10 and the filter cleaning pipes 11. As can be seen in FIG. 2 as viewed from the open end of the housing 2, the filter cleaning outlet opening 11a and the first opening of the sample pipe 10a are covered by the filter 13 and terminate at a distance further from the housing opening than the first outlet opening of the first purge pipe 8b.

[0123] In one or more examples, and as seen in FIG. 2, the outermost layer is the housing 2 of the gas sampling apparatus 1. Cooling means may preferably be embedded in the hosuing wall 3 so as to reduce of the temperature of the outermost layer, i.e. housing 2, of the gas sampling apparatus 1 (not shown). As can be seen in the present example, the housing 2 may be of a tubular shape, at least near the opening end of the housing.

[0124] In one or more examples, and as seen in FIG. 2, the second outlet opening(s) of the second purge system is located between the housing 2 and the layer comprising the filter 13. The second outlet openings are located at a position along the longitudinal centreline of the gas sampling apparatus 1 being prior to the location of the filter 13, such that the filter 13 is exposed to the gas media exiting the second outlet opening(s) 19a, whereby the exterior surface of the filter 14a may be cleaned. The cleaning process may preferably be aided by the filter cleaning system which pushes solid particles, such as dust towards the exterior surface of the filter 14a. In the example shown in FIG. 2, the second purge system comprises eight outlet openings, which may be visible from the open end of the housing 2 through the housing opening and the space provided between the interior housing surface 5 and the exterior surface of the filter 14a.

[0125] The gas sampling apparatus 1 of the present examples shown in FIGS. 1-2 is arranged to execute a powerful 3-step cleaning process by enabling the central purge system, the filter cleaning system and the peripheral purge system of the gas sampling apparatus 1. The gas sampling apparatus 1 of the present examples does not contain any mechanical cleaning means of the type, which is arranged to physically push or scrape aggregated particles of a surface, such as a plunger. The present example of a gas sampling apparatus 1 according to the invention provides a filter 13 placed in an open end of the housing 2a inside the process. The central first purge pipe 8 may preferably be used for blowing cleaning gas towards the housing opening 7 from the inside of the housing 2. Since the filter 13 is in the open end 2a near the tip of the housing 2, the gas sample led into the sample pipe 10 is free from solid particles, such as dust. In the gas sampling apparatus 1 of the present examples, compressed air is preferably used for cleaning the filter 13, the surface of the filter 14a and the interior housing surface 5.

[0126] In one or more examples, the gas sampling apparatus 1 is configured to be capable of extracting a gaseous sample from an environment of temperatures up to 1800 degrees Celsius, such as up to 1600 degrees Celsius, such as up to 1400 degrees Celsius. The gaseous environment containing the process gas to be analysed is typically at a pressure of between +50 mbar and −300 mbar compared to the pressure outside the gaseous environment, e.g. the outside of a chimney containing a process gas.

[0127] In one or more examples, gas sampling apparatus 1 is configured to extract a sample from an exhaust gas typically contain a concentration of O.sub.2 which is approximately 0-5 Vol %, a concentration of CO between 0-30,000 ppm, a concentration of NO between 0-4,000 ppm, a concentration of SO.sub.2 between 0-20,000 ppm, a concentration of CO.sub.2 between 0-30 Vol %, and a concentration of H.sub.2O between 0-40 Vol %.

[0128] In one or more examples, the gas sample apparatus 1 is in particular configured to extract a gaseous sample for extractive analysis of dust-containing gasses. In one or more examples, the concentration of dust may be between 0-2,000 g/m.sup.3.

[0129] The gas sample apparatus 1 may be mounted on an electric or pneumatic operated displacement means 23 as shown in FIG. 1a. In one or more examples, the gas sampling apparatus 1 may be arranged to be moved in and out of the process to remove deposits on the exterior housing surface of the housing wall 6.

[0130] In one or more examples, the gas sampling apparatus 1 is of a longitudinal extent which is of a size, so that gaseous samples extracted by the apparatus 1 is a “true” sample of the exhaust gas and preferably not affected by any gaseous media, which may exist at any mounting flanges within the environment or from layers of gaseous media produced near the interior walls enclosing the process gas to be analysed. The housing 2 of the gas sampling apparatus may be approximately 3 meters long, so as to be able to extract a sample from suitable positions within the gaseous environment.

[0131] In one or more examples, the housing wall 3 may preferably comprise one or more cooling means for water-cooling of the housing wall 3, which in turn provides mechanical strength of the housing and protects the housing from corrosion occurring at high temperatures. Especially in gaseous environments containing process gas e.g. from combustion within an industrial plant, the hot dust-containing and aggressive gas will condensate and aggregate when it is cooled by the lower temperature of the housing wall 3. The aggregation may comprise a mixture of dust, calcined raw meal, and sulphur or alkali. By the present invention and according to one or more examples, the gas sampling apparatus 1 can remove such aggregation adhering to the housing wall 3, in particular to the interior surface 5 and the rim of the housing wall 3a. In one or more examples, the sole purpose of the first purge pipe 8 is to provide a large burst of gas to blow off such aggregates.

[0132] In many gaseous environment containing solid particles, aggregation of solid particles may occur in the gaseous environment, which potentially can fall and land on the exterior surface of the gas sampling apparatus. The housing 2 of the gas sampling apparatus 1 may therefore preferably be configured to withstand such impacts, in particular, the housing 2 is shaped so as to provide a high degree of mechanical strength of the housing 2.

REFERENCE LIST

[0133] 1 Gas sampling apparatus [0134] 2 Housing [0135] 2a Open end of the housing [0136] 2b Back end of the housing [0137] 3 Housing wall [0138] 3a Rim surface of housing at the open end [0139] 4 Interior of the housing [0140] 5 Interior housing surface [0141] 6 Exterior housing surface [0142] 7 Housing opening [0143] 8 First purge pipe [0144] 8b First outlet opening of the first purge pipe [0145] 9 Exterior surface of the first purge pipe [0146] 10 Sample pipe [0147] 10a First opening of the sample pipe [0148] 11 Filter cleaning pipe [0149] 11a Filter cleaning outlet opening of the filter cleaning pipe [0150] 12 Second purge pipe [0151] 12a Second outlet opening of the second purge pipe [0152] 13 Filter [0153] 14a Exterior surface of the filter [0154] 14b Interior surface of the filter [0155] 15 Filter housing [0156] 16a Gas tank of a first gas supply system [0157] 16b Canon valve of a first gas supply system [0158] 18a Gas tank of a second gas supply system [0159] 18b Canon valve of the second gas supply system [0160] 19 Distributing means [0161] 19a Second outlet openings [0162] 20 Nozzle [0163] 21 Gas source for filter cleaning system [0164] 22 Extraction means [0165] 23 Gas analysis system [0166] 23 Displacement means