Patent Application
20230235878
The present invention relates to a fluidized bed gas distribution nozzle as used in a fluidized bed reactor and to a respective fluidized bed reactor.
Usually, fluidized bed reactors are in the form of combustors, boilers, gasifiers etc. The fluidized bed reactors usually comprise a grid (also called a grate or a perforated plate) supporting a bed of particulate material, for example a fuel material like coal, sand and ash. A reaction gas, such as air is introduced into said bed by means of fluidized bed gas distribution nozzles which form (eventually together with the grid) the fluidized bottom of the fluidized bed reactor. As a result of said gas which is fed into and passes the particulate material the particulate material receives a fluid like state.
Various types of fluidized bed gas distribution nozzles are known from the prior art. One type of those known nozzles to which the present inventions refers is known from EP 2 884 171 B1 and comprises the following features in its functional position: a gas inlet pipe, having an inner surface, an outer surface, a lower end section adapted to receive gas from an associated gas source, an upper end section, a plurality of openings preferably formed in the upper end section, each opening extending form the inner surface of the gas inlet pipe to the outer surface of the gas inlet pipe, a gas distribution cap connected or connectable to the gas inlet pipe, having an upper top, a lower bottom arranged at a vertical distance below said upper top and surrounding the gas inlet pipe (preferably arranged close to or touching the outer surface of the gas inlet pipe), a peripheral wall having an inner surface and an outer surface and extending between said upper top and said lower bottom and outlets within the peripheral wall extending from the inner surface of the peripheral wall to the outer surface of the peripheral wall.
Accordingly, gas may flow from within the lower end section of the gas inlet pipe through the openings at the upper end section into a space between corresponding sections of the outer surface of the gas inlet pipe and the inner surface of the peripheral wall of the air distribution cap and from said space through the outlets of the gas distribution cap into an ambient area.
This design is similar to a mushroom with its shaft being the gas inlet pipe and its head presenting the air distribution cap. In other words: gas is fed vertically upward through the gas inlet pipe, fed through the openings in the upper end section of the gas inlet pipe into the mostly annular space between the gas inlet pipe and the air distribution cap and further in a substantially horizontal direction through the outlets of the gas distribution cap and insofar through the peripheral wall of the gas distribution cap into the surrounding area and in particular into the fluidized bed of a fluidized bed reactor.
At a constant pressure of the gas provided from the associated gas source, the volume flowing through the fluidized bed distribution nozzle depends on the number, size and shape of the openings and of the outlets so that the fluidized bed gas distribution nozzles have to be constructed for a specific application case.
GB 1 396 588 A and CN 201 429 075 Y each disclose a fluidized bed gas distribution nozzle with a gas distribution cap being fixed to the gas inlet pipe in exactly one position, so that openings in the gas distribution cap match with openings in the gas inlet pipe.
It is therefore an object of the invention to resolve the drawbacks of the known nozzles and to provide a fluidized bed gas distribution nozzle which can be easily adapted to demand with regard to the amount of gas to be provided to the fluidized bed.
This object is solved with a fluidized bed gas distribution nozzle with the features of the independent claim. Preferred embodiments of the nozzle are described in the dependent claims and in the description, wherein single features of the preferred embodiments can be combined with each other in a technical meaningful manner.
The object is in particular solved in that the gas distribution cap can be connected at least in a first position and in a second position (preferably also in a third, in a fourth position or further positions) to the gas inlet pipe, wherein in the second position the gas distribution cap at least partly closes at least some of the openings.
By closing at least some of the openings at least partly the flow cross section for the gas is altered (in particular reduced) so that the amount of gas provided into the fluidized bed can be easily altered, when the gas is supplied with the same pressure. Therefore, it can be decided at the construction site of the fluidized bed reactor, if the gas distribution cap is connected to the gas inlet pipe in the first position or in the second (or even in a third, fourth or further) position.
Preferably, the second (or any further) position is a predetermined connecting position. Alternatively, the first position is a predetermined position. In a further embodiment, the first and the second (and any further) position is a predetermined connecting position. Accordingly, the gas inlet pipe and the gas distribution cap may be (physically/mechanically/structurally) embodied to provide a first predetermined connecting position and/or a second predetermined connecting position. Preferably, the gas inlet pipe and the gas distribution cap may be (physically/mechanically/structurally) embodied to provide a first predetermined connecting position and a second predetermined connecting position and preferably further predetermined connecting positions. Therefore, a respective predetermined connecting position is uniquely identified by a respective mechanical feature of the gas inlet pipe and its corresponding mechanical feature of the gas distribution cap.
Preferably, the gas inlet pipe and the gas distribution cap are embodied in such a way, that in the first position the openings of the gas inlet pipe are not closed (for example covered) by the gas distribution cap at all, so that all openings of the gas inlet pipe can be flown through by the gas provided through the lower end section.
Preferably, the gas distribution cap and the gas inlet pipe are embodied in such a way, that in the second position at least 25%, more preferably at least 40% or even at least 50% of the overall cross section area of all openings is closed by the gas distribution cap. It is also possible, that in the second position one half of the total number of openings are closed completely by the gas distribution cap.
If a gas distribution cap can be connected to the gas inlet pipe in three or four positions, 20% to 30% of the overall cross section area of all openings are closed in the second position, 40% to 60% are closed in the third position and 70% to 90% are closed in the fourth position. In case of three or four possible (in particular predetermined connecting) positions it is also possible, that one quarter of the number of openings are completely closed in the second position, one half of the number of openings are completely closed in the third position and three fourths of the number of openings are closed in the third position.
The first position may differ from the second position in that the gas distribution cap is displaced by a rotational movement in the circumferential direction of the gas inlet pipe. Accordingly, the gas distribution cap may be connected, in particular fixed, in two, three, four or more different rotational positions with regard to the gas inlet pipe.
Preferably, the first position of the gas distribution cap differs from the second position of the gas distribution cap in that the gas distribution cap is displaced axially in the longitudinal direction of the gas inlet pipe. Accordingly, the gas distribution cap may be connected/fixed in two, three, four or more different positions with regard to the longitudinal direction of the gas inlet pipe.
Of course, it is also possible that the gas distribution cap is displaced axially and rotationally in the different positions, wherein the directions refer to the gas inlet pipe.
In order to provide at least one predetermined connecting position in one embodiment recesses (as above mentioned mechanical feature) and corresponding protrusions (as above mentioned corresponding mechanical feature) may be formed at the upper end section of the gas inlet pipe and on an inner side of the upper top of the gas distribution cap, wherein the recesses are arranged within the corresponding protrusion in one of the positions (for example in the second position) and not in the other position (for example in the first position). Preferably, the recesses are formed on the upper end section of the gas inlet pipe and the protrusions are formed on the gas distribution cap, so that in the first position the protrusions are arranged (abut against) on the upper end face of the upper end section of the gas inlet pipe, while the protrusions are arranged within the respective recesses in the second position. Accordingly, the gas distribution cap is arranged longitudinally and rotationally offset between the first position and second position, whereby the recesses (receiving the protrusion) also avoid rotational movement of the gas distribution cap.
The recesses and protrusions may be formed in such a way that the protrusions are frictionally locked within the respective recesses.
In order to provide a third (in particular predetermined) position there might be formed a further group of recesses on the upper end section of the gas inlet pipe, in which the protrusions are arranged, when the gas distribution cap is arranged in the third position. There might be further (third or more) groups of recesses in which the protrusions are arranged in the respective fourth or further position. Also, a group of recesses may be provided in which the protrusions are arranged in the first position. The recesses for each of the positions differ from the recesses of the other positions in their circumferential position and depths.
In this case, if axial forces are applied to the top of the gas distribution cap the forces are transferred to the gas inlet pipe through the protrusions formed on the inner side of the gas distribution cap.
In order to provide different (predetermined) positions, in a further embodiment the gas inlet pipe may have at least a first pipe group of at least two pipe positioning holes (as above mentioned mechanical feature) and the gas distribution cap may have at least a first cap group of at least two cap positioning holes (as above mentioned corresponding mechanical feature), wherein at least one pin extends through the pipe positioning holes and the cap positioning holes to connect the gas distribution cap to the gas inlet pipe. The at least one pin secures the gas distribution cap against unintentional removement and can also provide force transfer, if forces are applied to the gas distribution cap.
When removing the at least one pin the gas distribution cap can easily be repositioned in a different position to the gas inlet pipe.
Also in this case, in the first or second position, the inner side of the gas distribution cap may abut at its upper top to the upper end face of the gas inlet pipe, while in the other position the at least one pin provides the connection between the gas distribution cap and the gas inlet pipe.
In order that the at least one pin can connect the gas distribution cap to the gas inlet pipe in more than one position, the gas inlet pipe comprises a second pipe group of at least two pipe positioning holes, wherein the pipe positioning holes of the second pipe group are arranged offset preferably in the longitudinal direction and in particular also in the circumferential direction relative to the pipe positioning holes of the first pipe group.
Alternatively, the gas distribution cap comprises a second cap group of at least two cap positioning holes, the cap positioning holes of the second cap group being arranged offset preferably in the longitudinal direction and in particular also in the circumferential direction relative to the cap positioning holes of the first cap group. Of course, for providing further positions there can be even further groups of pipe positioning holes or cap position holes which are arranged offset in the longitudinal direction and in particular also in the circumferential direction with respect to the positioning holes of the other groups.
The pipe positioning holes may be located below the openings in the gas inlet pipe. But preferably the pipe positioning holes are located above the opening in (the upper end section of) the gas inlet pipes.
The cap positioning holes may be located in the peripheral wall of the gas distribution cap above or below the outlets. But preferably the cap positioning holes are formed in the upper top of the gas distribution cap or in the peripheral wall close to the upper top.
The at least one pin may be dimensioned with its diameter in such a way, that it is frictionally locked in the positioning holes. Regarding its length the pin may be dimensioned such that it does not protrude over the outer surface of the cap.
There may be exactly one pin extending through two oppositely arranged cap positioning holes and two oppositely arranged pipe positioning holes in the respective position. In this case the pin extends over the inner cross section of the gas inlet pipe.
Alternatively, there may be one pin for each pair of a cap positioning hole and a pipe positioning hole in the respective position. Such a pin has preferably a length, so that it does not protrude over the inner surface of the gas inlet pipe and the outer surface of the gas distribution cap, thereby avoiding/minimizing contact with the gas (in particular within the gas inlet pipe) and/or with the particulate matter (in particular on the outside of the cap). This way, turbulences and erosion may be minimized/avoided.
The pin may be embodied as grooved dowel pin (German: Zylinderkerbstift).
In a preferred embodiment, the openings of the gas inlet pipe may be arranged at least in a first group of openings and in a second group of openings, wherein the first group of openings and the second group of openings are arranged offset to each other in the longitudinal direction of the gas inlet pipe, wherein in the second position the first group of openings is at least partly, preferably completely closed by the gas distribution cap. Accordingly, in the second position the openings of the second group are completely closed, while preferably, the other openings are not closed at all. This way turbulences of the gas flow by only partly closed openings are avoided.
In this regard, it is also preferred that the first group of openings and the second group of openings are each arranged in a row extending in the circumferential direction of the gas inlet pipe. Also, further (third, fourth or more) groups of openings may also be arranged behind above each.
For closing the openings at least in the second position, the gas distribution cap may have a collar (protrusion) extending into or surrounding the upper end section of the gas inlet pipe at least in the second position, whereby the collar at least partly closes at least some of the openings in the second position. The collar may extend uniformly and completely in the circumferential direction of the gas inlet pipe. Alternatively, the collar may have discrete sections arranged behind each other in the circumferential direction of the gas inlet pipe. Therefore, in the first position the collar may be arranged in such a way, that no openings of the gas inlet pipe are covered, while in the second position at least some of the openings are partly or even completely covered by the respective sections of the collar.
In the mounted state the outlets of the gas distribution cap and the openings of the gas inlet pipe may be arranged offset to each other in the longitudinal direction of the gas inlet pipe, so that gas flowing through the openings of the gas inlet pipe is directed downwardly in the space between the outer surface of the gas inlet pipe and the inner surface of the peripheral wall before leaving the gas distribution nozzle in a horizontal direction through the outlets of the gas distribution cap.
The invention also relates to a fluidized bed reactor including a plurality of the before described fluidized bed gas distribution nozzles. The plurality of nozzles (more than four, preferably more than 10 or even more than 20) may be arranged in rows or in staggered arrangement at the fluidized bottom of the fluidized bed reactor.
In an embodiment, the fluidized bed gas distribution nozzles of a first group have their respective gas distribution caps connected in the first position to their respective gas inlet pipe, while the fluidized bed gas distribution nozzles of a second group have their gas distribution caps connected in a second position to their gas inlet pipes. Accordingly, in a part of the fluidized bottom which comprises the gas distribution nozzles of the first group a greater volume of gas is provided by each nozzle than in the second part of the fluidized bottom comprising the fluidized bed gas distribution nozzles of the second group.
The technical background and the invention will now be described with regard to the drawings, which show embodiments of the invention in a schematic way in cross sectional view
The fluidized bed gas distribution nozzles depicted in
The gas inlet pipe 10 has an inner surface 10i, an outer surface 10o and extends from a lower end section 10l to an upper end section 10u. The lower end section 10l is adapted to receive gas from an associated gas source. A plurality of openings 12 is formed in the upper end section 10u of the gas inlet pipe 10. Each opening 12 extends from the inner surface 10i to the outer surface 10o of the gas inlet pipe 10. The openings 12 are arranged in two rows extending in the circumferential direction of the gas inlet pipe 10. The lower row of openings 12 forms a first group of openings 12 and the upper row of openings 12 forms a second group of openings 12.
The gas distribution cap has an upper top 20u and a lower bottom 20l, wherein the lower bottom 20l is arranged at a vertical distance below the upper top 20u and surrounds the gas inlet pipe 10, wherein the lower bottom 201 abuts against the outer surface 10o of the gas inlet pipe 10. A peripheral wall 20w of the gas distribution cap 20 extends from the upper top 20u to the lower top 20l. The peripheral wall 20w has an inner surface 20i and an outer surface 20o. Furthermore, outlets 22 are formed in the peripheral wall 20w, wherein the outlets 22 extend from the inner surface 20i to the outer surface 20o. Additionally, the gas distribution cap 20 has a collar 17 formed on the inner side at the upper top 20u.
According to the embodiment shown in
In the first position depicted in
In order to bring the gas distribution cap 20 in a different position the pin 18 is removed and the gas distribution cap 20 is displaced axially downwards into the position shown in
According to the embodiment of
In the second position depicted in
The gas distribution cap 20 can be lifted upwards from the second position shown in
Accordingly, in the second position the gas entering the gas inlet pipe 10 at its lower end section 10l can only flow through the lower row of openings 12, so that the amount of gas flowing through the fluidized bed gas distribution nozzle is reduced with respect to the first position, when the same gas pressure is applied.
According to the embodiment shown in
In the first position depicted in
In order to bring the gas distribution cap 20 in a further position the pin 18 is removed and the gas distribution cap 20 is turned and displaced axially downwards into the second position shown in
In order to bring the gas distribution cap 20 in an even further position the pin 18 is removed and the gas distribution cap 20 is turned and displaced axially downwards into the third position shown in
While in the embodiments of
| Number | Date | Country | Kind |
|---|---|---|---|
| 20172713.8 | May 2020 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/061745 | 5/4/2021 | WO |
