Burner Assembly and Method of Operating Same

Abstract

The present invention refers to a burner arrangement for burning combustible gas supplied, for example, by a blower (1), in which case the burner arrangement has at least one gas supply pipe (2) for supplying the gas to be burned, in which case the burner arrangement comprises a nozzle arrangement (3) placed downstream from the gas supply pipe (2) in an intended flow direction (S) of the gas, in which case the nozzle arrangement (3) has one or several gas outlet openings (5) through which the gas to be burned can flow out from the nozzle arrangement (3) before it is burned, and in which case the gas outlet opening(s) (5) has/have a total gas outlet area. According to the invention, it is provided for the burner arrangement to comprise means used to change the total gas outlet area of the nozzle arrangement (3) within defined limits so the flow speed of the gas flowing out of the gas outlet opening(s) (5) can be regulated. Furthermore, a method for operating a corresponding burner arrangement is suggested, characterized as a result of this that the total gas outlet area of the nozzle arrangement (3) is adjusted in such a way while the burner arrangement is operating that the flow speed of the gas flowing out through the gas outlet opening(s) (5) always stays within defined limits.

Description

The present invention refers to a burner arrangement for burning a flammable gas, supplied by a blower, for example, in which case the burner arrangement has at least one gas supply pipe for supplying the gas to be burned, in which case the burner arrangement comprises one nozzle arrangement arranged downstream from the gas supply pipe in an intended flow direction of the gas, in which case the nozzle arrangement has one or several gas outlet openings through which the gas to be burned can flow out of the nozzle arrangement before it is burned, and in which case the gas outlet opening(s) has or have a total gas outlet area.

These burner arrangements are used, for example, in the degassing of installations built for storing and/or transporting fluids or gases. Some of these installations are fluid or gas tanks in various industrial facilities (e.g. refineries), gasoline stations, ships or pipelines, for example. These installations must be emptied from time to time, but the gases remaining inside the installation are frequently poisonous, easily flammable or explosive and cannot be allowed to escape into the environment. It has therefore proven effective to suction the corresponding gases from the installation after it has been emptied and burn them in a controlled way with the help of a burner arrangement.

However, it is worth mentioning here that the gases to be burned, depending on where the frequently mobile burning equipment is used and, in particular, on the object to be degassed, can fluctuate considerably with regard to their type and composition or the existing gas pressure. However, since the known burner arrangements are generally designed for a certain gas type and concentration, the burning quality or gas transfer is not optimal for each application being considered.

The task of the present invention is therefore to suggest an improved burner arrangement or a better method for operating a corresponding burner arrangement.

The task is solved by a burner arrangement and a method for operating it that has the characteristics of the independent claims.

Thus, the burner arrangement is characterized by the fact that it comprises means with whose help the total gas outlet area of the nozzle arrangement can be changed within defined limits. In this case, the total gas outlet area is understood to be the sum of the flow cross-sections of all openings through which the gas supplied to the burner arrangement can flow out of it through the gas supply pipe and be burned (if there is only one gas outlet opening, then the total gas outlet area equals the flow cross-section of this opening). The gas comes preferably from the object to be degassed, which can be a gas or fluid tank, tanker or pipeline. The burner arrangement is preferably designed as mobile unit so it can be transported to the respective object to be degassed.

In any case, the execution of the burner arrangement according to the invention allows the total gas outlet area to be changed between the corresponding limits so that as a result of this, the flow speed of the gas escaping through the gas outlet opening(s) can be adjusted. This, in turn, has the advantage that the height of the flame forming in the area of the gas outlet opening(s) when the burner arrangement is being operated can also be adjusted. This is decisive because a flame that is too high (owing, for example, to a pressure increase within the gas supply pipe or an increase in the proportion of flammable gas components) is associated with the danger of flame “lifting”, which can ultimately lead to the extinction of the flame or insufficient gas burning. On the other hand, if the flame becomes too small because the pressure within the gas supply pipe drops, then there is the danger that the flame will retrogress into the gas supply pipe and reach the object to be degassed in the worst-case scenario.

With the present invention, it now possible to regulate the height of the flame by adjusting the total gas outlet area within predefined limits that depend on the miscellaneous geometry of the nozzle arrangement. If, for example, the gas pressure is increased within the gas supply area (because the rotational speed of the blower pushing the gas into the burner arrangement is increased due to an insufficient flame temperature, for example), then it would be conceivable to increase the total gas outlet area of the burner arrangement to prevent an enlargement of the flame height.

If the pressure becomes lower, then it would again be possible to lower the total gas outlet area so the flame retrogression mentioned above can be prevented.

In principle, it is advantageous within the framework of the invention if the means according to the invention used to change the total gas outlet area are placed in the area of the gas outlet opening(s), in which case—regarding the possibility of influencing the total gas outlet area—reference is made to the description given below. Generally speaking, however, sliders that can be moved relative to the gas outlet openings can be used, in particular, to change their total flow cross-section.

It is likewise advantageous if the nozzle arrangement has several gas outlet openings from which one or several can be fully or partially closed. While it is also conceivable to equip the nozzle arrangement with only one gas outlet opening, several gas outlet openings are preferred, lying preferably on a flat or curved plane and, in particular, arranged next to one another. One or more sealing elements are preferably assigned to the gas outlet openings, used to close the individual gas outlet openings either fully or partially, and preferably independently from the remaining gas outlet openings, which can generally be executed as bore holes.

It is also advantageous if at least some of the gas outlet openings are executed as through holes of a gas outlet element fixed in place or movably mounted. It is furthermore advantageous if there is a gas outlet element that has, for example, a flat section where the gas outlet openings are found. The gas outlet element can be arranged so it is fixed in place in the burner arrangement. It is likewise conceivable for the gas outlet element to be designed so it can be moved linearly or swiveled around a swivel axis or rotated around a rotating axis so the escaping gas can be influenced by adjusting the gas outlet element. Additionally, the gas outlet element can be part of the gas supply area or be directly or indirectly connected to it. It is furthermore conceivable for the gas supply element and/or the gas supply pipe to comprise one or several air supply pipes through which the combustion air can be introduced into the burner arrangement.

It is advantageous if the gas outlet element is actively connected to at least one sealing element, in which case the gas outlet element and the sealing element are movably mounted relative to one another. For example, it is conceivable to provide one or several sealing elements that—similarly to a slider—are movable relative to the gas outlet openings (to achieve this, the burner arrangement can comprise, for example, one or several guides for the sealing element(s)). Likewise, the sealing element(s) can be mounted in such a way that it/they can swivel around a swivel axis or rotate around a rotating axis. Depending on the position of the sealing element, which is preferably placed tightly against the gas outlet element, the total gas outlet area can finally be adjusted between the corresponding limits, in which case the movement of the closing element(s) can take place manually or with the help of a drive of the burner arrangement, which can in turn be actively connected to its control system. If the control system is connected to the corresponding sensors, which monitor the volumetric flow or flow speed of the gas to be burned, for example, the volumetric flow or flow speed of the combustion air supplied and/or the temperature and/or the height of the flame(s) of the burner arrangement and/or the rotational speed of a blower (ventilator or fan) supplying the gas, then it would also be conceivable for the control system to be designed so it adjusts the total gas outlet area depending on the measured values delivered by one or several of the above-mentioned sensors.

It is also extremely advantageous if the gas outlet element and/or sealing element is/are executed flat, at least partially so. For example, the sealing element can comprise a metallic surface with numerous openings that, in turn, serve as gas outlet openings. It is likewise possible to execute the sealing element(s) as a metallic plate, whereby the gas outlet element(s) and the sealing element(s) run preferably at least partially parallel to one another, are placed tightly against one another and/or are movably mounted relative to one another.

There are additional advantages if the gas outlet element and/or the sealing element are at least partially curved. In the case of the gas outlet elements, the curvature can be found in the area of the gas outlet openings or also contiguous to them. Likewise, the sealing element(s) can have curved and also flat surface sections so it/they can cling to the gas outlet element.

It is especially advantageous when the gas outlet element and the sealing element are designed at least following a cylinder's surface area partially, in which case the curvature radii of gas outlet element and sealing element are different. For example, it would be conceivable for the gas outlet element to be at least partially cylindrical and surrounded by a cover element that is also at least partially cylindrical, in which case the rotating axes of the respective cylinders run advantageously concentrically to one another. Alternatively, it is naturally also possible for the cover element to form the inner cylinder and the gas outlet element the outer cylinder. In any case, the gas outlet element should have gas outlet openings on merely one part of its circumferential area, so the gas outlet openings and the cover element can cover one another as a result of a relative movement between gas outlet element and cover element, allowing the gas outlet openings to be closed.

It is therefore advantageous if at least one part of the gas outlet openings can be covered by one or several cover elements, in which case the corresponding gas outlet openings and the cover element(s), respectively, can be moved relative to one another. For example, it could be conceivable to arrange the gas outlet element rigidly and the cover element in a way it slides over the gas outlet element, in order to cover the individual gas outlet openings fully or partially depending on the position of the cover element, making it possible to adjust not only the flow speed of the gas flowing out of the still opened gas outlet openings but also the height of the flame.

It is additionally advantageous if the nozzle arrangement comprises several gas outlet elements, in which case every one of the gas outlet elements has one or several gas outlet openings. Finally, depending on the gas pressure in the gas supply area, individual gas outlet elements can be turned on or off tom adjust the flame height to the desired intensity.

It is equally advantageous if the burner arrangement is equipped with an air supply through which the air can be introduced to it, preferably to its gas supply area. By adjusting the air volume flow, combustion can be influenced and maximum possible gas burning can be ensured. The air supply, in turn, can be connected to a blower to feed the air with a certain pressure to the burner arrangement, especially to its gas supply area.

The method according to the invention to operate a corresponding burner arrangement is characterized by the fact that the total gas outlet area of the nozzle arrangement is adjusted in such a way while the burner arrangement is being operated that the flow speed of the gas escaping through the gas outlet opening(s) remains within defined limits. For example, it would be conceivable to set a target flow speed X as well as an upper and lower limit, in which case the limits deviate upwards and downwards from the limit by a magnitude that corresponds, for example, to 10% of the limit. In any case, adjusting the total gas outlet area opens up the possibility of burning different types of gases with different pressures and compositions in the most efficient way possible without lifting the flame generated during combustion from the nozzle arrangement or the flame retrogressing into the gas supply area.

It is particularly advantageous if the total gas outlet area of the nozzle arrangement is adjusted manually or automatically before, during and/or after operating the burner arrangement. The manual adjustment can be done, for example, by changing the total gas outlet area with the help of one or several cover elements, displaced relative to the gas outlet openings of a gas outlet element of the burner arrangement and, when doing so, cover more or fewer gas outlet openings. An automatic adjustment could be done, for example, by moving the cover or sealing element mentioned in this description between given positions with a servomotor, in which case the position could depend on one or several measured values, whereby in this case the gas pressure inside the gas supply pipe or the temperature of the flame(s) could be taken into account, for example.

It can therefore be advantageous when the total gas outlet area of the nozzle arrangement or the flow speed of the gas escaping through the gas outlet opening(s) is adjusted depending on the gas pressure that prevails inside the gas supply pipe, in which case the pressure is monitored preferably with the help of a pressure sensor. The pressure can, for example, fluctuate owing to rotational speed fluctuations of a blower pushing the gas into the burner arrangement during the combustion process. Since a pressure increase with unchanging total gas outlet area would lead to an increase in flame height, it is advantageous if the total gas outlet area is changed, based on the above-mentioned pressure, in order to maintain the flame height as constant as possible. Accordingly, it could be an advantage to reduce the total gas outlet area when a pressure drop is detected or to enlarge the total gas outlet area if there is a corresponding pressure increase. In this context, it could be possible to install a pressure sensor near the gas supply pipe to measure the respective gas pressure and use it accordingly for changing the total gas outlet area. However, it could also be conceivable to change the total gas outlet area depending on the gas volume flow delivered or the rotating speed of a gas-delivering blower, in which case the corresponding sensors could also be provided for measuring the magnitudes mentioned above.

Moreover, it is advantageous if the gas pressure prevailing inside the gas supply pipe is adjusted, for example, by changing the rotational speed of the blower that supplies the gas into the burner arrangement depending on the temperature of the flame(s) burning in the area of the gas outlet opening(s) when the burner arrangement is operating. Since the flame temperature is an important indicator of the course of the combustion, it is advantageous to increase or decrease the pressure when the temperature lies outside a given range (the temperature is preferably monitored with the help of a temperature sensor). However, since the increase or decrease or the above-mentioned pressure with unchanging total gas outlet area would lead, in turn, to an undesired change of the gas flow speed in the area of the gas outlet openings and change of flame height, it is advantageous to change the total gas outlet area accordingly as well when the pressure changes.

It is additionally advantageous if the total gas outlet area of the nozzle arrangement or the flow speed of the gas escaping through the gas outlet opening(s) depending on the rotating speed of a blower supplying the gas into the burner arrangement and/or its gas volume flow and/or depending on the volumetric flow, the pressure and/or the flow speed being adjusted during the operation of the burner arrangement via the gas supply pipe or an air quantity supplied via the separate air supply pipe. Finally, depending on the selection of factors to be considered, flow speed or flame height can be maintained very reliably within certain limits, thus allowing reliable gas combustion even with fluctuating gas composition or gas pressure. Additional advantages of the invention are described in the following embodiments shown in these figures:

FIG. 1 a schematic burner arrangement according to the present invention,

FIG. 2 a top view of a part of a nozzle arrangement of a known burner arrangement,

FIG. 3 a top view of a section of a burner arrangement according to the invention,

FIG. 4 the section according to FIG. 3 with a changed position of the cover element,

FIG. 5 a cross-sectional view of a section of another burner arrangement according to the invention,

FIG. 6 the section according to FIG. 5 with changed position of the cover element,

FIG. 7 a lateral view of a section of a burner arrangement according to the invention,

FIG. 8 the section according to FIG. 7 with changed position of the cover element,

FIG. 9 a section of another burner arrangement according to the invention,

FIG. 10 the section according to FIG. 9 with changed position of the gas outlet element, and

FIG. 11 the section according to FIGS. 9 and 10 with once again a changed position of the gas outlet element.

FIG. 1 shows a schematic view of a burner arrangement according to the invention that comprises, in principle, a nozzle arrangement 3, through which a gas that can be supplied with the help of a gas supply pipe 2 can be burned in form of one or several flames 14. The gas comes, for example, from a storage tank 10 connected to the burner arrangement via the gas supply pipe 2, in which normally gas or a fluid such as fuel is stored. The corresponding storage tanks 10 (or also other objects that preferably store or transport hydrocarbons) must be cleaned from time to time. To accomplish this, gas residues remaining in the storage tank 10 must be disposed of by removing them from the storage tank 10. Since generally it is not allowed to let the gas escape into the atmosphere when the storage tank 10 (or some other object) is degassed, the burner arrangement according to the invention is used so the gas can be burned, thus preventing environmental pollution.

Apart from the nozzle arrangement 3 (of which several can also be provided) connected through one or several gas supply pipes 2 with one or several objects to be degassed, the burner arrangement comprises preferably a holding device 13 to ensure a safe upright position of the nozzle arrangement(s) 3. The holding device 13 can be a stand like the one indicated in FIG. 1. It is also conceivable for the burner arrangement and at least a part of the gas supply pipe 2 to be a component of a mobile incinerator that can be transported from one operating site to another depending on need (the gas supply pipe 2 can also have several parts and have one part that is a component of the burner arrangement, and consist of one or more parts that connect the burner arrangement to the object to be degassed on site).

So the nozzle arrangement 3 can be supplied with the combustion air that is necessary in some cases, it can have one or several air supply pipes 4 and FIG. 1 shows that they can be put in various places of the burner arrangement or gas supply pipe 2 (contrary to FIG. 1, it is generally sufficient if only one of the air supply pipes 4 shown is provided). Alternatively or additionally, one or several air admission openings 11 can be provided, which can be placed, for example, in the area of a sheathing 12 of the nozzle arrangement 3 (the sheathing 12 serves for partially shielding the flame(s) 14 to minimize a negative influence on flame generation by wind, for example).

Furthermore, FIG. 1 shows exemplarily that the burner arrangement can be connected with one or several blowers 1 that supply the burner arrangement with combustion air or gas, which is in turn suctioned from the object to be degassed with the corresponding blower 1.

Finally, one or several pressure sensors 6 can be provided to monitor gas pressure inside one or several sections of the gas supply pipe 2 or the burner arrangement and be used, for example, with a control system so the control system according to the invention of the total gas outlet area of the gas outlet opening(s) 5 of the nozzle arrangement(s) 3 can be controlled.

As can be seen in FIG. 1, the burner arrangement has a section (for example on the end of the gas supply pipe 2), through which the gas can flow out of the burner arrangement through one or several gas outlet opening (s) 5 and burn in form of a flame 14, in which case this section is named gas outlet element 7, which can naturally also be a separate component that is, in turn, connected to the gas supply pipe 2.

FIG. 2 shows a top view of a known nozzle arrangement 3 or its gas outlet element 7. As can be seen in this drawing, the gas outlet element 7 comprises numerous gas outlet openings 5 through which the gas flows out of the nozzle arrangement 3 and burns as flame 14.

The disadvantage in this state of the art is the fact that the gas pressure prevailing in the gas supply pipe 2 (and as a rule generated by a blower 1) can fluctuate or be unequal during the degassing of the object to be degassed or depending on it or the gas found inside it that needs to be burned.

If the pressure in the gas supply pipe 2 now changes compared to a standard value, then owing to the constant as well as the size and number of gas outlet openings 5 given in the total gas outlet area, there must be a change in the gas flow speed in the area of the gas outlet openings 5 and with it, cause a change in the height H of the flame 14. However, this is disadvantageous because the flame 14 can lift, extinguish or, retrogress against the gas flow direction into the gas supply pipe 2 and, in the worst-case scenario, reach all the way into the object to be degassed.

To solve this problem, the invention suggests that the burner arrangement should have means used for changing the total gas outlet area of the nozzle arrangement 3 within defined limits so the flow speed of the gas escaping through the gas outlet opening(s) 5 can be adjusted. These means can be preferably one or several sealing elements 8 executed, for example, as cover, and movably mounted relative to the gas outlet opening(s) 5, for example.

Thus, it is possible to dose the gas outlet opening(s) 5 fully or partially or a few of the several gas outlet openings 5 depending on need, so that the size of the total gas outlet opening consisting preferably of several gas outlet openings 5 can be changed.

If the pressure now increases within the gas supply pipe(s) 2, then with the help of the invention, it is possible to increase the total gas outlet area in order to prevent an increase in the flow speed of the escaping gas or maintain it as low as possible. In the contrary case, when the pressure in the gas supply pipe(s) 2 is reduced because the flame temperature exceeds a limit, for example, it could be possible to reduce the size of the total gas outlet area to prevent a decrease of the height H of the flame 14.

Ultimately, the nozzle arrangement 3 designed according to the invention can finally regulate the flow speed of the gas flowing out through the gas outlet opening(s) 5 to eventually maintain the height H of the flame(s) 14 as constant as possible.

FIGS. 3 to 11 show possible constructive solutions that allow the total gas outlet area to be adjusted or changed according to this invention.

Thus, according to FIGS. 3 und 4, it would be possible, for example, to equip the gas outlet element 7 with a cover element 9 (which would take over the function of the sealing element 8 described in detail in the description). The cover element 9 can, for example, be formed by a flat metallic plate that can be rotated around a rotating axis 16. To reach the respective final positions unerringly (all gas outlet openings 5 “opened” (FIG. 3) or all gas outlet openings 5 “closed”; FIG. 4 shows an intermediate position), a stop 15 can be provided so the cover element 9 can bump into it as soon as one of the final positions is reached (cf. FIGS. 3 and 4).

FIGS. 5 to 8 show another way of regulating the total gas outlet area between the respective limits. It would be possible, for example, to design the gas outlet element 7 as a cylinder so the supply of the gas to be burned could be introduced, for example, through a front side of the cylinder surface (FIG. 7 shows a possible placement of the air supply pipe 4, which incidentally is not shown in the remaining figures of this embodiment for achieving a better overview). The opposite front side should in this case be closed.

Apart from the gas outlet element 7, a preferably cylindrical cover element 9 is finally provided too, so gas outlet element 7 and cover element 9 can be twisted relative to one another to vary the number of gas outlet openings 5 covered, and thereby dosed, by the cover element 9 (cf. FIGS. 5 and 6 as well as FIGS. 7 and 8, where FIG. 8 shows the arrangement according to FIG. 7 with the cover element 9 twisted towards the back). To do this, it is advantageous if the gas outlet element 7 and cover element 9 have different curvature radii R.

FIGS. 9 to 11 show a final embodiment in which the gas outlet element 7 also has many gas outlet openings 5 that can generally be executed as bore holes (and in other embodiments too) or also as fine perforation of the gas outlet element 7. The gas outlet element 7 and the movable cover element 9 surrounding it and movable relative to it can, in turn, be cylindrical, in which case other shapes are conceivable too.

Naturally, it is by and large conceivable to mount the gas outlet element 7 rigidly and the cover element 9 movably, but it is just as well conceivable to mount the gas outlet element 7 movably compared to a rigidly arranged cover element 9. Likewise, the cover element 9 can surround the gas outlet element 7 from outside or vice versa.

In any case, it can be advantageous if the cover element 9 has an opening 17 that deviates from a rectangular shape. As results from the context of FIGS. 9 to 13, the total gas outlet area can in this case be regulated more precisely, especially in the area of a small total gas outlet area (see FIG. 11). in which case it is generally advantageous if there is a non-linear correlation between the position of the cover element 9 and the total gas outlet area.

This invention is not restricted to the embodiments shown and described. Modifications as part of the patent claims are just as possible as any combination of the described characteristics, even if they are shown and described in different parts of the description or in the claims or in different embodiments.

LIST OF REFERENCE CHARACTERS

1 Blower

2 Gas supply pipe

3 Nozzle arrangement

4 Air supply pipe

5 Gas outlet opening

6 Pressure sensor

7 Gas outlet element

8 Sealing element

9 Cover element

10 Storage tank

11 Air admission opening

12 Sheathing

13 Holding device

14 Flame

15 Stop

16 Rotating axis

17 Opening

H Height of the flame

R Curvature radius

S Flow direction

Claims

1. Burner arrangement for burning combustible gas supplied, for example, by a blower (1),

in which case the burner arrangement has at least one gas supply pipe (2) for supplying the gas to be burned,

in which case the burner arrangement comprises a nozzle arrangement (3) placed downstream from the gas supply pipe (2) in an intended flow direction (S) of the gas,

in which case the nozzle arrangement (3) has one or several gas outlet openings (5) through which the gas to be burned can flow out from the nozzle arrangement (3) before it is burned, and

in which case the gas outlet opening(s) (5) has/have a total gas outlet area, characterized in that the burner arrangement comprises means used to change the total gas outlet area of the nozzle arrangement (3) within defined limits so the flow speed of the gas flowing out of the gas outlet opening(s) (5) can be regulated.

2-15. (canceled)