DE102010035153A1 - Crude gas flare with adjustable opening cross-section for flaring flammable gases and combustion of raw gases - Google Patents

Abstract

The invention relates to a device for flaring combustible gases with an adjustable opening cross-section, this device having three different tubes which are arranged around a common longitudinal axis, and wherein the tubes are arranged at least in sections in a common cross-sectional plane, and the inner tube as Gas supply pipe is of the type, and this pipe has an adjustable cross-section at the opening that ends upwards in the vertical direction, through which the flow of gas can be closed or regulated, and which is equipped with an automatable mechanism for adjusting the opening cross-section. The device typically also includes at least one air baffle, feed devices for an inert gas and an ignition mechanism, which is associated with high reliability of the flaring of the gas and low emissions of nitrogen oxides and soot. The invention also relates to a method for operating this device, which is suitable for flaring raw gases to be burned.

Description

The invention relates to a device as Rohgasfackel with adjustable Fackelrohgasaustritt, which consists of several nested tubes forming a torch for flaring raw gases, this arrangement includes a variable in cross-section nozzle, which controls the supply of raw gas, so that at the outlet side the torch is an approximately constant speed and on the inlet side an approximately constant pressure is adjustable. In this way, an unwanted extinction and vagrancy of the torch flame can be avoided during operation. The invention also relates to a method for burning coke oven raw gases, wherein a constant flow velocity is achieved at the exit side of the torch by the use of a cross-sectionally adjustable nozzle and the use of pipes with a certain aspect ratio.

Many processes in the industry produce gases that are not reused because this is undesirable for economic or technical reasons. Examples of such processes are the production of coke oven gas or the production of refinery products, which produce waste gases which are destroyed by burning or burning. This process is also referred to as flaring, as the combustion process is usually performed at the exit end of an open tube and is not used to generate energy. The gases to be flared typically accumulate in the event of a fault in the gas-treating or gas-cleaning part of the installation at too high a pressure or fluctuating pressure and can therefore no longer be used.

It is also possible that the gases intended for combustion have a chemical composition which results in a low calorific value and therefore can only be reused to a limited extent. These reasons also mean that the intended flaring of the gases entails further technical problems. For flaring, the gas to be bled must be provided under a sufficient and constant pressure to ensure adequate combustion. Since the combustion gases are usually discharged into the surrounding atmosphere, the flared gas must be burned as completely as possible and also without interruption. This means that not only the pressure of the flammable gas, but also the air supply to the combustion must be regulated. Furthermore, it must also be ensured that the escaping gas can be immediately re-ignited on extinction of the flame at the outlet end of the flare tube, which requires the presence of a reliable ignition device.

Finally, it is endeavored to prevent a so-called "vagrancy" of the flame or at least greatly attenuate. This process refers to the uncontrolled flickering of the flame at the exit end of the tube, especially under the action of wind. This vagabond shifts the focus of heat of the flame, damaging the flares or even adjacent equipment.

Devices which are suitable for flaring a gas to be burned, and which work to avoid the problems mentioned, are known in the art. The US 5472340 A describes a device which claims a flame igniter and a raw gas flare provided for this purpose. The apparatus comprises at least two tubes of different lengths arranged around a common longitudinal axis, the tubes being at least partially arranged as outer and inner tubes so that air can enter through the gap for combustion and the inner tube at one end allows the access of combustion gas, so that the device forms a torch. The torch also has baffles at at least two locations, whereby the gas and air flow can be directed during combustion. If necessary, the ignition device can also be operated with solar energy.

In particular, this invention solves the problem of providing a reliable torch igniter. However, said device can be operated without interruption only by a relatively constant pressure of the gas to be burned. It is not called a step in the process to burn the gas to be burned even at low pressure without interference. Also, no process step is called to mitigate the effects of wind and to ensure an atmosphere-independent, trouble-free combustion. Finally, the combustion of high-carbon gases also seeks to minimize the formation of soot to preclude harmful effects on the surrounding atmosphere. Also for this measure, no method step is mentioned in said patent application. Finally, the device can also be damaged by an excessive heat load, as it occurs, for example, with stray flame direction.

It is therefore an object to provide a device that allows the most complete and soot-free combustion of the gas to be flared, the output of soot and should be as low as possible to nitrogen oxides. The combustion should take place without interruption and interruption even when the admission pressure of the gas to be burned fluctuates. The flame direction should be as constant as possible in order to keep the heat load of the flare material low. The effect of wind on the flame should have no disturbing influences. Finally, the device should also allow a reliable ignition of the gas to be burned.

The invention solves this problem by a device for flaring combustible gases with adjustable opening cross-section, said device having three different tubes which are arranged about a common longitudinal axis, and wherein the tubes are arranged at least partially in a common cross-sectional plane, and the inner Pipe is designed as a gas supply pipe, and this tube has at the vertically upwardly ending opening a cross-sectional adjustable aperture through which the flow of gas is closable or regulated, and which is equipped with an automatable mechanism for adjusting the opening cross-section. The apparatus typically also includes at least one air baffle, and outer tube formations that permit directional supply of air and trouble-free burning of the gas to be combusted.

The apparatus further includes an ignition device which allows for the trouble-free ignition of the gas, and an inert medium supply means, which is preferably water vapor, to minimize the formation of soot and carbon monoxide, i. H. to burn the hydrocarbon-containing gas as completely as possible. Due to the adjustable cross-section aperture of the admission pressure of the outflowing gas and its outflow velocity can be regulated within wide limits or kept constant. As a result, combustion and flame formation can be largely controlled and optimized.

• • ein Gaszuleitungsrohr, welches eine in vertikale Richtung aufwärts endende Öffnung aufweist,
• • ein Mischerrohr, welches einen größeren Innenquerschnitt aufweist als der größte Außenquerschnitt des Gaszuleitungsrohres, so dass zwischen diesen Rohren ein Raum frei bleibt, wobei das Mischerrohr aus einem konzentrischen Rohr, einem sich aufwärts im Querschnitt öffnenden Diffusor und einem sich abwärts im Querschnitt öffnenden Konfusor besteht,
• • mindestens ein Luftleitblech, welches sich zwischen dem Innenrohr und dem Mischerrohr befindet,

und welche dadurch gekennzeichnet ist, dass

• • um das Gaszuleitungsrohr ein Innenrohr angeordnet ist, welches einen größeren Innenquerschnitt als der größte Außenquerschnitt des Gaszuleitungsrohres aufweist, und einen kleineren Außenquerschnitt als der kleinste Innenquerschnitt des Mischerrohres, und
• • an der in vertikaler Richtung aufwärts endenden Öffnung eine im Querschnitt verstellbare Blende (auch Irisdüse genannt) angeordnet ist, durch welche der Strom an Gas verschließbar oder regulierbar ist, und die mit einem automatisierbaren Mechanismus zur Verstellung des Öffnungsquerschnittes ausgestattet ist.

Claimed is in particular apparatus for flaring combustible gases with adjustable opening cross-section, comprising

• A gas supply pipe having a vertically upward opening,
• A mixer tube which has a larger inner cross section than the largest outer cross section of the gas supply tube so that a space remains free between these tubes, wherein the mixer tube consists of a concentric tube, an upwardly open in cross-section diffuser and a downwardly opening in cross-section Konfusor .
• At least one air baffle, which is located between the inner tube and the mixer tube,

and which is characterized in that

• • An inner tube is arranged around the gas supply pipe, which has a larger inner cross section than the largest outer cross section of the gas supply pipe, and a smaller outer cross section than the smallest inner cross section of the mixer pipe, and
• Is arranged on the vertically upwardly ending opening in a cross-section adjustable aperture (also called Irisdüse), through which the flow of gas is closed or regulated, and which is equipped with an automatable mechanism for adjusting the opening cross-section.

The design of the tubes can also be made arbitrarily. The outer tube, also called mixer tube, is typically provided at the top with an upwardly extending extension. This is also called diffuser. This upper part serves as a flame guide. The lower part of the mixer tube serves primarily for the supply of air. This part of the mixer tube is also called confuser and expands in an opening down. This can also be provided with guide plates or baffles for the directed supply of combustion air. Guide plates or air baffles can in principle be provided on each tube and in any arrangement. Embodiments for designing the tubes are known in the art.

The combustion air passes through the confuser of the mixing tube and is guided between the mixing tube and the inner tube as well as between the inner tube and the gas supply tube. This leads to a two-stage combustion, which counteracts the formation of nitrogen oxides.

The aperture, which adjusts or closes the cross section of the inner tube, may be of any kind as long as it reliably controls or closes the cross section of the inner flare tube. The diaphragm is preferably made of a refractory material so as to be resistant to the temperatures of the flame forming at the torch exit. Also, the visor material must be resistant to possible corrosive components of the gas to be flared. This is preferably a heat and corrosion resistant steel.

In an exemplary embodiment, the diaphragm consists of plates which are concentric, tangentially and circularly horizontally in the direction of the gas feed tube center are closed.

The diaphragm consists in a further exemplary embodiment of plates, which are concentric, tangential and circular in the direction of the gas feed tube center are closed. This corresponds to an embodiment, as it is comparatively present in a photographic diaphragm. To open or close these are then moved in the horizontal direction to the center of the tube. The f-number and size can be arbitrary. It is important that the material of the panel is resistant to the prevailing temperatures and gas or liquid components. An embodiment for diaphragms which close tangentially and circularly in the direction of a tube center ("iris diaphragms") are known from US Pat US 4094492 A known. However, this document teaches no regulation of flares for the combustion of gases, with the resulting special requirements such as high temperatures and resistance to corrosive gases.

In another embodiment, the plates may be pivoted upwardly or downwardly in a vertical direction for opening. The plates are then formed as lamellae, which are preferably pulled by an actuating mechanism down in the flow direction. This corresponds to an embodiment, as it is comparatively present in a funnel aperture. The further the fins are pulled down, the farther the aperture opens. The f-number, their size and material can also be arbitrary. An embodiment for diaphragms which are pivoted upwards or downwards in a vertical direction for opening in the tube ("iris nozzles") are known from US Pat DE 10002529 A1 known. This document also teaches no regulation on flares for the combustion of gases, with the resulting special requirements such as high temperatures and resistance to corrosive gases.

The aperture is exemplified by an electric adjusting mechanism adjustable. But it can also be a pneumatic adjusting mechanism can be selected. The choice of the type of adjusting mechanism is left to the person skilled in the art. The arrangement of the diaphragms can be selected temporarily or permanently so that a recess remains free in the middle of the diaphragm arrangement.

In one embodiment of the invention is located at least one point within the gas supply pipe, the inner tube or the mixer tube, a nozzle for supplying an inert gas. This is typically water vapor. The supply of water vapor as a driving gas allows depending on the combustion conditions, a stable flame guidance and a significant reduction in the formation of soot and carbon monoxide with nearly complete to complete combustion of the hydrocarbons in the gas. This device may be a nozzle or a simple feed nozzle. Nozzles for supplying water vapor into gases to be flashed are known in the art. An exemplary embodiment of feed nozzles teaches by way of example DE 69917073 T2 , These may in turn be equipped with a regulating device. This regulating device can be of any kind. This can also consist as the device according to the invention of diaphragms.

In a further embodiment of the invention, the device according to the invention contains a device for igniting the gas. Thus, it is possible, for example, to arrange the ignition lances within the cross section of the inner tube or the mixer tube. In an advantageous embodiment, these are at least two ignition lances, which are arranged at an angle of 80 ° to 100 °, and through which an electric arc voltage or spark can be generated. The electrical voltage can be generated in any way. This can also be chosen arbitrarily high to ensure a reliable ignition. An example of a prior art Zündlanzenanordnung gives the US 4147498 A ,

Also, the supply of the gas to the torch can be arbitrary. In a simple embodiment, this is a simple tube, which opens into the gas supply of the inner tube, so that the pressure of the outflowing gas is controlled only by the diaphragm according to the invention. In a further and preferred embodiment is located below the inner tube and the mixer tube, a flare valve, which can be shut off. This can be of any kind. This can for example consist of a dip cup with water supply, so that the pressure of the gas supplied to the immersion cup is already regulated or shut off to some extent already in the supply to the torch. An embodiment of a pressure-regulating immersion cup describes the EP 1390440 B1 ,

The torch valve is in a further embodiment of at least one immersion cup, which consists of two halves, these halves are to open independently to regulate or close. In this way, the flare valve is redundant, so that it is still functional even in case of failure of a half and the gas to be flared must not be discharged unburned into the atmosphere. Gas-supplying flare valves with immersion cups are well known in the art. The torch valves are preferably pneumatic with a pneumatic cylinder open, closed or closed. To practice the present invention, it is possible for each half to be actuated individually. Due to the presence of two pneumatic cylinders, the immersion cup is still functional even if one cylinder fails.

Also claimed is a process for burning coke oven raw gases, which uses the device according to the invention. This typically introduces the gas to be flared into the gas feed tube and controls the adjustment of the exit velocity of the gas to be flared by the aperture-adjustable aperture. Typically, the velocity of the flue gas to be flared out during flaring is controlled so that it remains constant and ensures trouble-free flame guidance. This procedure can also prevent unwanted vagrancy or the extinction of the flame.

In one embodiment of the invention, a reduced flame temperature is effected by a two-stage combustion. This two-stage combustion is achieved by selecting the ratios of the cross sections of the gas supply pipe and the inner pipe and the inner pipe and the mixer pipe such that a reduced air supply amount into the inner pipe results in a substoichiometric combustion air ratio (first combustion stage) and the relatively increased air supply amount through the annular gap between Mixer tube and inner tube in the upper part of the mixer tube to a superstoichiometric combustion air ratio in the mixer tube above the inner tube (second combustion stage) leads. This two-stage combustion counteracts the formation of nitrogen oxides.

In a further embodiment of the invention, an inert gas is introduced into the gas supply pipe, the inner pipe or the mixer pipe. It is preferably water vapor. However, it is also possible to introduce additional raw gas which is intended for flaring. Finally, in a further embodiment of the invention, a mixture of water vapor and gas to be burned off can also be introduced. This is preferably supplied at a pressure of 7 to 15 bar.

For flaring all gases are suitable, which have a sufficiently high calorific value for flaring. These are typically coke oven raw gases or refinery gases.

The supply of the gas to be burned in the torch according to the invention can be made arbitrarily. In a simple embodiment, this can be done unregulated by a simple tube. In a preferred embodiment, an upstream flare valve is disposed below the flare tubes, which contains at least one immersion cup.

This is as described preferably made of two independently operated diving cups. The two halves of the immersion cup of the upstream flare valve can be synchronously opened, controlled or closed by a respective pneumatic cylinder in a preferred embodiment.

It is also possible to actuate each half of the entire immersion cup individually. In this way, an undesirable blockage of the valve in case of failure of a control device can be counteracted, so that the gas does not have to be discharged unburned into the atmosphere. The torch according to the invention may be associated with a gas reservoir as a buffer tank to counteract a pressure build-up when closing the diaphragm or the upstream torch valve.

Finally, by using the method according to the invention, the number of raw gas flares can be considerably reduced, since the heat generation of the flares is lower and the reliability is increased. Often, half of the usual number of torches is sufficient. Also, the torches can be constructed lower because the heat radiation is lower and does not have to be expected with the emission of unburned gas.

The invention has the following advantages: The torch can be operated at a constant exit velocity of the gas to be burned, resulting in a stable flame guidance with high reliability of flaring. Vagabundant flames with an undesirable shift in the center of gravity are avoided, so that damage to the torch and impairment of the environment can be ruled out. The action of the wind results in significantly less damage to the torch process than in prior art devices. The possibility of arranging a reliable ignition device ensures that combustion always takes place so that the undesired emission of unburned gas practically does not occur. The formation of soot in the flaring of carbon-rich gas can be virtually eliminated by supplying inert gas and the formation of nitrogen oxides can be successfully counteracted by a two-stage combustion.

The invention will be explained in more detail with reference to four drawings, the exemplary Embodiments play, wherein the invention is not limited to these embodiments.

1 shows a Rohgasfackel invention without vorgelagertem torch valve in the side view and the aperture in the open state. 2 shows a Rohgasfackel invention with upstream torch and the aperture in the open state. 3 shows a Rohgasfackel invention with upstream torch and the aperture in the closed state. four shows a raw gas flare according to the invention in the vertical view from above.

1 shows a raw gas flare according to the invention ( 1 ) in lateral view. The raw gas ( 2 ) flows through the gas supply pipe ( 3 ) upwards. The gas supply pipe ( 3 ) is of the so-called inner tube ( four ) surround. This in turn is from the mixer tube ( 5 ), which consists of a central part ( 5a ), a confuser ( 5b ) and a diffuser ( 5c ) consists. The gas supply pipe ( 3 ) contains at the upper exit end ( 3a ) an aperture ( 6 ), which opens in the vertical direction by lifting. You can see the adjusting mechanism ( 7 ), which the aperture ( 6 ) opens, regulates or closes. At the upper exit end of the torch a flame forms ( 8th ).

2 shows a raw gas flare according to the invention ( 1 ) in lateral view with upstream torch valve ( 9 ). The raw gas ( 2 ) flows through the gas supply pipe ( 3 ) upwards. The gas supply pipe ( 3 ) contains at the upper exit end ( 3a ) an aperture ( 6 ), which opens in the vertical direction by lifting. This one is here in open form ( 6a ) The adjustment mechanism ( 7 ), which the aperture ( 6 ) opens, regulates or closes. Above this aperture ( 6 ) there is an ignition mechanism ( 10 ), which consists of two offset by 90 ° arranged ignition lances ( 10a . 10b ) consists. From the ignition lances ( 10a . 10b ), a spark or an arc ( 10c ) be generated. The electrical voltage is divided by two poles ( 10d . 10e ). Watching are also baffles ( 11 ), which in the inner tube ( four ) or in the mixer tube ( 5 ) are arranged. The torch ( 1 ) also contains a delivery device ( 12 ) for an inert gas ( 12a ), which is preferably water vapor. Below the torch ( 1 ) is an upstream flare valve ( 9 ), which consists of two halves ( 9a . 9b ) consists of a dipping cup. Each of these two halves has a lid which can be lifted by a pneumatic actuator.

3 shows a raw gas flare according to the invention ( 1 ) in lateral view with upstream torch valve ( 9 ). The raw gas ( 2 ) flows through the gas supply pipe ( 3 ) upwards. The gas supply pipe ( 3 ) contains at the upper exit end ( 3a ) an aperture ( 6 ), which opens in the vertical direction by lifting. This is here in closed form ( 6b to see). As a result, the gas flow is completely or almost shut off.

four shows a raw gas flare according to the invention ( 1 ) in vertical view from above. You can see the cross section of the curved mixer tube ( 5 ), the inner tube ( four ) and the gas supply pipe ( 3 ). The apertures ( 6 ) are arranged tangentially and can be opened by lateral pivoting. You can see here the adjusting mechanism ( 7 ) and the ignition lances ( 10a . 10b ). You can also see the feed nozzles ( 12 ) for the inert gas ( 12a ). This is preferably water vapor.

LIST OF REFERENCE NUMBERS

1

Rohgasfackel

2

raw gas

3

Gas supply pipe

3a

Outlet end of the gas supply pipe

4

inner tube

5

mixer tube

5a

Middle part of the mixer tube

5b

constrictor

5c

diffuser

6

cover

6a

Open aperture

6b

Closed aperture

7

mechanism

8th

flame

9

torch valve

9a

Dip cup half

9b

Dip cup half

10

ignition mechanism

10a

Inner ignition lance

10b

External ignition lance

10c

Electric arc

10d

power supply

10e

power supply

11

baffles

12

feed nozzles

12a

inert gas

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5472340 A [0005]
• US 4094492 A [0015]
• DE 10002529 A1 [0016]
• DE 69917073 T2 [0018]
• US 4147498A [0019]
• EP 1390440 B1 [0020]

Claims (18)

Device with adjustable opening cross-section for flaring flammable gases, comprising • a gas supply pipe having a vertically upward-ending opening, • a mixer tube which has a larger inner cross section than the largest outer cross section of the gas supply pipe, so that a space remains free between these tubes wherein the mixer tube consists of a concentric tube, a diffuser opening upwards in cross-section and a confuser opening downwards in cross-section, at least one air guide plate, which is located between the inner tube and the mixer tube, characterized in that the gas supply tube surrounds Inner tube is arranged, which has a larger inner cross section than the largest outer cross section of the gas supply pipe, and a smaller outer cross section than the smallest inner cross section of the mixer tube, and • at the end in the vertical direction opening is arranged in a cross-section adjustable aperture, through which the flow of gas is closed or regulated, and which is equipped with an automatable mechanism for adjusting the opening cross-section. Device with adjustable opening cross-section for flaring combustible gases according to claim 1, characterized in that the diaphragm consists of plates which are concentric, tangential and circular horizontally in the direction of the gas supply tube center can be closed. Device with adjustable opening cross-section for flaring combustible gases according to claim 1, characterized in that the diaphragm consists of plates which are concentric, secant and can be closed directly horizontally in the direction of the gas supply tube center. Device with adjustable opening cross-section for flaring flammable gases according to claim 1, characterized in that the plates are pivoted to open upwards or downwards in the vertical direction. Device with adjustable opening cross section for flaring flammable gases according to one of claims 1 to 4, characterized in that the aperture is adjustable by an electric adjusting mechanism. Device with adjustable opening cross section for flaring flammable gases according to one of claims 1 to 4, characterized in that the aperture is adjustable by a pneumatic adjusting mechanism. Device with adjustable opening cross section for flaring flammable gases according to one of claims 1 to 6, characterized in that there is at least one nozzle for supplying an inert gas at least one point within the gas supply pipe, the inner tube or the mixer tube. Device with adjustable opening cross section for flaring combustible gases according to one of claims 1 to 7, characterized in that within the cross section of the inner tube or the mixer tube at least two ignition lances are arranged, which are arranged at an angle of 80 ° to 100 °, and which with an electrical voltage an arc or spark can be generated. Device with adjustable opening cross-section for flaring flammable gases according to one of claims 1 to 8, characterized in that the Gaszuführrohr with a torch valve, which is located below the inner tube and the mixer tube, can be shut off. Device with adjustable opening cross-section for flaring flammable gases according to claim 9, characterized in that the flare valve consists of at least one immersion cup, which consists of two halves, these halves are to open independently to regulate or close. A method for the combustion of raw gases with a device according to one of claims 1 to 10, characterized in that the adjustment of the form or the exit velocity of the gas to be flared by the adjustable cross-section aperture. A method of burning raw gases according to claim 11, characterized in that the ratios of the cross sections of gas supply pipe and inner tube and the inner tube and mixer tube are chosen so that the reduced air supply amount into the inner tube to a stoichiometric combustion air ratio in the inner tube and the relatively enlarged air supply amount the annular gap of the mixer tube and inner tube in the mixer tube leads to a superstoichiometric combustion air ratio above the inner tube. A process for the combustion of raw gases according to any one of claims 11 or 12, characterized in that the exit velocity of the outgoing flare gas during flaring remains the same. A process for the combustion of raw gases according to any one of claims 11 to 13, characterized in that in the gas supply pipe, the inner tube or the mixer tube, an inert gas is introduced. Process for the combustion of raw gases according to Claim 14, characterized in that the inert gas is water vapor. Process for the combustion of raw gases according to claim 14, characterized in that the inert gas is a mixture of water vapor and gas to be burned off. A process for the combustion of raw gases according to any one of claims 14 to 16, characterized in that the inert gas is supplied at a pressure of 7 to 15 bar. A process for the combustion of raw gases according to one of claims 11 to 17, characterized in that the two halves of the immersion cup of the flare valve are opened, regulated or closed synchronously by a pneumatic cylinder.

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