JP2013536396A - Rough gas bleeder / flare with variable opening cross section for bleed-off / flaring of flammable gas and process for flaming gas combustion - Google Patents

Abstract

The present invention relates to a device with a variable opening cross section for extracting / flaring flammable gases, said device comprising three different tubes arranged around a common longitudinal axis. Are arranged at least partially at one common cross-section level, the inner tube is designed as a gas supply tube, and this tube comprises a variable cross-section baffle in an opening that terminates vertically upward, said baffle throttle being a gas It is used to close and control the flow and has an automatable mechanism to adjust the opening cross section. The present invention is also typically configured with at least one air guide plate, inert gas supply, and ignition mechanism, thereby providing high bleed-off / flaring reliability and low nitrogen oxides and soot. Emissions are brought about. The invention also relates to a process for operating this device which is suitable for extracting / flare burning flammable crude gas.
[Selection] Figure 2

Description

  The present invention is designed as a crude gas bleeder / flare with a variable bleeder / flared coarse gas outlet consisting of several tubes nested inside to form a bleeder / flare for extracting / flaring the crude gas. The apparatus includes a variable cross-section nozzle that is adjusted to a substantially constant speed on the bleeder / flare outlet side and adjusted to a substantially constant pressure on the bleeder / flare inlet side. To control the supply of crude gas. In this way, unwanted bleeder / flare flame extinction and fluctuations during operation are avoided. The present invention also relates to a process for coke oven crude gas crude gas combustion in which a constant flow rate is achieved on the discharge side of the bleeder / flare by using a variable section nozzle and a specific section ratio tube.

  Many industrial processes produce gases that are not used for further use because they are not desired for economic or technical reasons. Examples of such processes include the production of coke oven gas and the production of purified products, resulting in waste gas that is destroyed by combustion. This process is also called bleed-off / flaring because the combustion process is usually performed at the outlet end of the open tube and is not used for energy generation. The extracted / flare burning gas is typically obtained during excessive pressure and pressure fluctuations during failures in the gas processing or gas purification plant sector and is therefore not used for further utilization.

  The gas to be combusted is composed of a chemical composition that produces a lower calorific value, and therefore there is a possibility that the gas can only be used for limited applications. For these reasons, the intended bleed-off / flaring of the gas also faces further technical challenges. For bleed-off / flaring, the extracted / flare burning gas must be supplied at a sufficient and constant pressure to ensure proper combustion. Since the combustion gases are normally discharged into the surrounding ambient air, the extracted / flared burning gas must be burned as completely as possible and without interruption. This means that not only the pressure of the extracted / flared gas but also the air source for combustion needs to be controlled. In addition, when the flame is extinguished, it is necessary to ensure that the leaking gas can be immediately reignited at the discharge end of the bleeder tube, which requires the use of a reliable ignition device.

  Finally, efforts are made to avoid or at least significantly reduce the so-called “fluctuation” of the flame. This process implies an uncontrolled flickering of the flame at the outlet end of the tube, especially under the influence of wind. This fluctuation causes a change in the maximum heat flux intensity position of the flame in a way that can damage the bleeder / flare facility or even adjacent plant parts.

  Devices are known in the prior art that are suitable for extracting the burned gas / flare burning and designed to avoid such problems. U.S. Pat. No. 5,472,340A describes a flare igniter and a device claiming a crude gas flare for this purpose. The device includes at least two conduits of different lengths and sharing a common longitudinal axis so that the combustion air can flow into an area located between both conduits at least in cross-section. In addition, the combustion gas can flow into one end of the internal conduit in such a way that it is arranged as an external and internal conduit and the device forms a flare. Fins for deflecting the gas and air flow during combustion are included in at least two locations of the flare. Optionally, the ignition device can be operated using a solar power source.

  In particular, the invention solves the problem of providing a reliable flare ignition device. However, the mentioned device can be operated without interruption only when the burned gas is at a relatively constant pressure. No mention is made of process steps that make it possible to extract gas / flare combustion even at low pressures. It also does not describe process steps that reduce the effects of wind and enable turbulent combustion that is independent of atmospheric conditions. Finally, when burning high carbon gas, efforts are being made to minimize soot formation in order to eliminate harmful effects on the surrounding atmosphere. Furthermore, the process steps for this countermeasure are not stated in the patent application. Finally, the device can be damaged by excessive heat loads occurring, for example, in the direction of flame fluctuation.

  Therefore, it is an object of the present invention to provide a device that allows for as complete and soot-free combustion of the extracted / flared combustion gas as possible and minimizes soot and nitrogen compound emissions. is there. Combustion must occur in an undisturbed and uninterrupted manner even if the inlet pressure of the extracted / flared gas varies. In order to keep the bleeder / flare material at a low heat load, the flame direction should be as constant as possible. The influence of the wind on the flame must not have a disturbing influence. Finally, the device must also provide reliable ignition of the extracted / flared gas.

  The present invention is a variable aperture cross-section device for extracting / flaring flammable gases, comprising three tubes disposed about a common longitudinal axis, the tubes being at least partially The inner pipe is designed as a gas supply pipe, and the pipe is provided with a variable cross-section baffle in an opening that terminates vertically upward, and the baffle is used to close or control the gas flow. The object is achieved by the device comprising an automatable mechanism for adjusting the opening cross section. The device is typically also provided by at least one air guide plate and a molded part of the outer tube that allows the gas to be supplied and withdrawn in the direction of the air and to be discharged and burned undisturbed. Composed.

  The invention provides an igniter that allows undisturbed ignition of the gas and a steam, preferably with steam, to minimize soot and carbon monoxide formation, i.e. to burn the hydrocarbon gas as completely as possible. An inert gas supply device is also included. The leaking gas inlet pressure and its discharge rate can be controlled over a wide range and can be kept constant by a variable cross-section baffle. As a result, combustion and flame formation can be controlled to the maximum and optimized.

In particular, the present invention is a device with a variable opening cross section for extracting / flaring flammable gas,
A gas supply pipe having an opening that terminates in the upper vertical direction. A mixing pipe having an inner cross section larger than the maximum outer cross section of the gas supply pipe, leaving a free space between the mixing pipe and the gas supply pipe. , Arranged around a mixing tube / gas supply pipe composed of a diffuser whose cross section increases upward and a diffuser whose cross section increases downward; an inner cross section larger than the maximum outer cross section of the gas supply pipe; It is composed of at least one air guide plate disposed between the inner tube of the outer cross section smaller than the minimum inner cross section of the mixing tube and the inner tube and the mixing tube,
A variable cross-section baffle disposed in an opening that terminates vertically upward, characterized by the baffle being used to close or control gas flow and with an automatic mechanism for adjusting the open cross-section Claim a device.

  These tube embodiments may also be in any form. Typically, the outer tube, also called a mixing tube, has an extension at its top that extends upward. It is also called a diffuser. The upper part is used to direct the flame. The lower part of the mixing tube is mainly used for supplying air. This part of the mixing tube, also called a confuser, extends towards the lower opening. The part may also comprise a baffle plate or an air guide plate for supply with the direction of the combustion air. In principle, baffle plates or air guide plates can be provided in each tube and in any arrangement. Embodiments of these tube designs are known in the prior art.

  Combustion air enters the mixing tube through the confuse and is sent to the space between the mixing tube and the inner tube and between the inner tube and the gas supply tube. This results in a two-stage combustion that prevents the formation of nitrogen oxides.

  The baffle that adjusts or closes the cross section of the inner tube may be of any type as long as it reliably controls or closes the internal bleeder / flare tube. The aperture is preferably made of a refractory material to withstand the heat of the flame formed at the bleeder / flare exit. The material of the baffle must be resistant to any corrosive components contained in the extracted / flare burning gas. This material is preferably heat and corrosion resistant steel.

  In a typical embodiment, the baffle is comprised of a plate that can be closed concentrically, tangentially and annularly with respect to the center of the gas supply tube. This corresponds to one embodiment, as is relatively present in the photographic aperture. To open and close, these plates are moved horizontally towards the center of the tube. The number and dimensions of the plates may be optional. It is important that the material of the baffle be resistant to common temperatures and gas or liquid components. An embodiment of a baffle (“iris shutter”) that closes tangentially and annularly towards the tube center is known from US Pat. No. 4,094,492A. However, this patent specification teaches nothing about controlling the bleeder / flare to burn the gas, including the resulting special requirements, such as resistance to high temperatures and corrosive gases.

  In a further exemplary embodiment, the baffle consists of a plate that can be closed concentrically, in the secant direction, and directly horizontally towards the center of the gas supply tube.

  In a further embodiment, the plate can be tilted upward or downward in the vertical direction to open. In this case, the plate is designed as a blade which is preferably pulled upward in the flow direction by an actuator. This corresponds to one embodiment, as is relatively present in the photographic aperture. The more the blade is pulled upward, the more the aperture will open. The number of blades, their dimensions, and materials may also be optional. An embodiment of a blade (“iris nozzle”) that is pulled vertically upwards or downwards in a tube to open is known from DE 10002529 A1. However, this patent specification teaches nothing about controlling the bleeder / flare to burn the gas, including the resulting special requirements, such as resistance to high temperatures and corrosive gases.

  In a typical manner, the iris can be adjusted by an electric actuator. However, pneumatic actuators can also be selected. The choice of actuator type is left to the practitioner skilled in the art. The arrangement of the baffles can be selected temporarily or permanently in such a way that there is an opening in the center of the baffle arrangement.

  In one embodiment of the present invention, a nozzle is provided for supplying an inert gas to at least one position inside the gas supply pipe, the inner pipe, or the mixing pipe. Typically this is water vapor. Depending on the combustion conditions, the supply of water vapor as the driving gas allows continuous flame control and significant reduction in soot and carbon monoxide formation, completing the combustion of the hydrocarbons contained in the gas. The device can be a nozzle or a simple inlet tube. Nozzles for supplying water vapor into the extracted / flared burning gas are known from the prior art. An exemplary embodiment of the supply nozzle is taught by DE 69917073 T2. These nozzles may comprise any type of control device. The latter may also consist of a baffle like the inventive device.

  In a further embodiment of the invention, the inventive device comprises a device for igniting a gas. For example, it is possible to place the ignition lance in the cross section of the inner tube or the mixing tube. In an advantageous embodiment, these are at least two ignition lances arranged at an angle of 80 ° to 100 °, which can be used to generate an electric arc or spark by voltage. The voltage may be generated by any means. It can be chosen freely to ensure reliable ignition. An example of a prior art igniter rod arrangement is given by US Pat. No. 4,147,498A.

  The gas inlet / gas supply to the bleeder / flare may also be of any type. In a simple embodiment, this is a simple tube that enters the gas inlet of the inner tube in such a way that the pressure of the leaking gas is controlled only by the baffle of the present invention. In a further preferred embodiment, a bleeder / flare valve that can be closed is arranged below the inner tube and the mixing tube. This bleeder / flare valve may be of any type. For example, it can consist of a float cup with a water supply, allowing the pressure of the gas supplied in the float cup to already be controlled to some extent or shut off at the gas inlet to the bleeder / flare. . An embodiment of a pressure controlled float cup is described in EP 1390440B1.

  In a further embodiment, the bleeder / flare valve includes at least a float cup composed of two compartments that are opened, controlled and closed independently of each other. In this way, the bleeder / flare valve has a redundant configuration. As a result, the bleeder / flare valve can be operated even in the event of a failure of one section, and the extracted gas remains in the atmosphere in an unburned state. It is prevented from being released. Gas supply bleeder / flare valves with float cups are well known in the prior art. The bleeder / flare valve is preferably opened, controlled and closed by air pressure using a pneumatic cylinder. For this embodiment of the invention, each compartment can be operated independently. Since two pneumatic cylinders are available, the float cup can still be operated if one cylinder fails.

  The present invention also claims a coke oven crude gas combustion process using the inventive device. The process supplies the extracted / flare burning gas into the gas supply pipe and uses a variable cross-section baffle to control the extraction rate setting of the extracted / flare burning gas. Typically, the rate of leaked gas that is withdrawn / flared is controlled during bleed-off / flaring in such a way that the rate remains constant and undisturbed flame control is ensured. This procedure also prevents unwanted flickering and extinguishing of the flame.

  In one embodiment of the invention, the two-stage combustion results in a decrease in flame temperature. In this two-stage combustion, the ratio of the cross section of the gas supply pipe to the inner pipe and the ratio of the cross section of the inner pipe to the mixing pipe are reduced. The first combustion stage), and the proportional increase in the amount of air supplied to the upper part of the mixing pipe via the annular gap between the mixing pipe and the inner pipe is higher than the stoichiometric combustion air ratio in the mixing pipe above the inner pipe (second Achieved by selecting to provide a combustion stage). This two-stage combustion prevents the formation of nitrogen oxides.

  In a further embodiment of the invention, an inert gas is supplied into the gas supply tube, the inner tube or the mixing tube. This inert gas is preferably water vapor. However, additional crude gas that is subject to bleed-off / flaring can also be supplied. Finally, in a further embodiment of the invention, a mixture of water vapor and extracted / flared gas can also be supplied. This mixture is preferably fed at a pressure of 7 to 15 bar.

  Any gas with a sufficiently high calorific value is suitable for bleed-off / flaring. Typically, these gases are coke oven crude gas and refinery gas.

  Supply of the extracted / flared burning gas to the bleeder / flare of the present invention can be done as needed. In a simple embodiment, this is done by a simple tube in an uncontrolled manner. In a preferred embodiment, an upstream bleeder / flare valve containing at least one float cup is positioned below the bleeder tube.

  As mentioned above, this valve is preferably made of two float cups that may be designed as two compartments that are operated independently. In a preferred embodiment, each of the two compartments of the upstream bleeder / flare valve float cup can be opened, controlled, or closed in synchronism by a pneumatic cylinder.

  However, each compartment of all float cups can be operated independently. In this way, undesired blockage of the valve in the event of a control device failure can be counteracted and the gas is prevented from being discharged into the atmosphere in an unburned state. In accordance with the present invention, a gas collection vessel / receiver serving as a buffer vessel may be placed in the bleeder / flare to mitigate the pressure rise when closing the baffle or upstream bleeder / flare valve.

  Finally, the use of the process of the present invention allows for a significant reduction in the number of crude gas bleeders / flares because the bleeder / flare exotherm is lower and more reliable. Half of the normal bleeder / flare number is often sufficient. Breeders / flares can also be designed to be lower in height because they have lower thermal radiation and do not need to take into account the emission of unburned gas.

  The present invention has the following advantages. The bleeder / flare can be operated at a constant discharge rate of the extracted / flared burning gas, resulting in high reliability of continuous flame control and associated bleed-off / flaring. To prevent bleeder / flare damage and environmental destruction, flame fluctuations and associated undesired changes in the maximum heat flux point are avoided. The disturbing effect on the bleed-off / flaring process due to wind effects is considerably less than in prior art devices. The possibility of installing a reliable ignition device ensures continuous combustion in such a way that unwanted unburned gas emissions are substantially suppressed. The supply of inert gas can substantially eliminate the formation of soot during extraction / flare combustion of high carbon gas, and the formation of nitrogen oxides is successfully prevented by two-stage combustion.

  The present invention will be described in more detail with reference to four drawings showing exemplary embodiments, but the present invention is not limited to these embodiments.

FIG. 1 shows a side view of a crude gas bleeder / flare of the present invention that does not include an upstream bleeder / flare valve and an open position baffle. FIG. 2 shows a crude gas bleeder / flare of the present invention including an upstream bleeder / flare valve and an open position baffle. FIG. 3 shows a crude gas bleeder / flare of the present invention including an upstream bleeder / flare valve and a baffle in a closed position. FIG. 4 shows the inventive crude gas bleeder / flare as viewed from above.

  FIG. 1 is a side view of the crude gas bleeder / flare (1) of the present invention. The crude gas (2) flows out to the upper end through the gas supply pipe (3). The gas supply pipe (3) is surrounded by a so-called inner pipe (4). The inner tube is similarly surrounded by a mixing tube (5) comprised of a central portion (5a), a diffuser (5b), and a diffuser (5c). A baffle (6) is prepared at the upper discharge end (3a) of the gas supply pipe (3), which is opened by lifting vertically upward. An actuator (7) is shown that opens, controls and closes the baffle (6). A flame (8) occurs at the upper discharge end of the bleeder / flare.

  FIG. 2 is a side view of the crude gas bleeder / flare (1) and upstream bleeder / flare valve (9) of the present invention. The crude gas (2) flows out to the upper end through the gas supply pipe (3). A baffle (6) is prepared at the upper discharge end (3a) of the gas supply pipe (3), which is opened by lifting vertically upward. Here it is shown in the open position (6a). Also shown is an actuator (7) that opens, controls and closes the baffle (6). Above this baffle (6) is an ignition mechanism (10) composed of two ignition lances (10a, 10b) arranged 90 ° apart. With these ignition lances (10a, 10b), an ignition spark or an electric arc (10c) can be generated by applying a voltage supplied by two poles (10d, 10e, not shown here). Also shown here is an air guide plate (11) arranged in the inner tube (4) or the mixing tube (5). The bleeder / flare (1) also comprises a supply device (12) for an inert gas (12a), preferably water vapor. The upstream bleeder / flare valve (9) is provided below the bleeder / flare (1) and includes a float cup composed of two compartments (9a, 9b). Each of the two compartments has a cover that can be lifted by a pneumatic actuator.

  FIG. 3 is a side view of the crude gas bleeder / flare (1) and upstream bleeder / flare valve (9) of the present invention. The crude gas (2) flows out to the upper end through the gas supply pipe (3). A baffle (6) is prepared at the upper discharge end (3a) of the gas supply pipe (3), which is opened by lifting vertically upward. Here it is shown in the closed position (6b) so that the gas flow is completely or almost completely interrupted.

  FIG. 4 is a top view of the crude gas bleeder / flare (1) of the present invention. Cross sections of the curved mixing tube (5), inner tube (4), and gas supply tube (3) are shown. The baffle (6) is arranged in the tangential direction and can be opened by lateral inclination. Shown here are an actuator (7) and an ignition lance (10a, 10b). Also shown here is a supply nozzle (12) for an inert gas (12a), preferably water vapor.

DESCRIPTION OF SYMBOLS 1 Coarse gas bleeder / flare 2 Coarse gas 3 Gas supply pipe 3a Discharge end of gas supply pipe 4 Inner pipe 5 Mixing pipe 5a Center part of mixing pipe 5b Condenser 5c Diffuser 6 Baffle 6a Opened baffle 6b Closed baffle 7 Actuator 8 Flame 9 Breeder / Flare valve 9a Float cup compartment 9b Float cup compartment 10 Ignition mechanism 10a Inner ignition lance 10b Outer ignition lance 10c Electric arc 10d Power supply 10e Power supply 11 Air guide plate 12 Supply nozzle 12a Inert gas

Claims (18)

A device (1) having a variable opening cross section (3a) for extracting / flaring flammable gas (2),
Gas supply pipe (3) with an opening (3a) that terminates vertically upward
Since the inner cross section is larger than the maximum outer cross section of the gas supply pipe (3), there is a mixing pipe (5) in which free space remains between the gas supply pipe (3). A mixing tube composed of a diffuser (5c) with a larger cross section and a diffuser (5b) with a cross section increasing downwards;
An inner pipe (4) disposed around the gas supply pipe (3), the inner cross section being larger than the maximum outer cross section of the gas supply pipe (3), and the minimum inner cross section of the mixing pipe (5) An inner pipe (4) having a smaller outer cross section,
At least one air guide plate (11) disposed between the inner tube (4) and the mixing tube (5);
In the device including
A variable-section baffle (6) is placed in the vertically upward opening (3a), and the restriction is used to close and control the gas flow (2) to adjust the opening cross-section. Device (1), characterized in that it has a mechanism (7) that can be automated.   3. A device (1) having a variable opening cross section for extracting / flaring the combustible gas (2) according to claim 1, wherein the baffle (6) is directed in the horizontal direction toward the gas supply pipe center (3). A conceivable product composed of concentric, tangential, and annularly closable plates.   The device (1) having a variable opening cross section for extracting / flare burning the combustible gas (2) according to claim 1, wherein the baffle (6) is concentric in the direction of the gas supply pipe center (3). A device (1), characterized in that it is composed of a plate that can be closed horizontally, in the secant direction and directly horizontally.   2. A variable opening cross-section device (1) for extracting / flare burning combustible gas (2) according to claim 1, wherein the baffle (6) is tilted upward or downward in the vertical direction to open. Device (1) characterized in that it is composed of a plate that can be used.   A device (1) having a variable opening cross-section for extracting / flaring the combustible gas (2) according to any one of claims 1 to 4, wherein the baffle (6) is driven by an electric actuator (7). Device (1) characterized by being adjustable.   5. A device (1) of variable opening cross-section for extracting / flaring the combustible gas (2) according to any one of claims 1 to 4, wherein the baffle (6) is a pneumatic actuator (7). Device (1) characterized in that it can be adjusted by   7. A device (1) of variable opening cross-section for extracting / flare burning the combustible gas (2) according to any one of claims 1 to 6, at least for supplying an inert gas (12a) A device (1), wherein one nozzle (12) is arranged at least at one position inside the gas supply pipe (3), the inner pipe (4), or the mixing pipe (5). .   8. A device (1) of variable opening cross-section for extracting / flaring the combustible gas (2) according to any one of claims 1 to 7, at least arranged at an angle of 80 ° to 100 ° Two ignition lances (10a, 10b) are arranged inside the cross section of the inner tube (4) or the mixing tube (5), and an electric arc or an ignition spark (10c) can be generated by voltage using these. Invented product (1).   A device (1) having a variable opening cross section for extracting / flaring combustion of the combustible gas (2) according to any one of claims 1 to 8, wherein the gas supply pipe (3) is the inner pipe ( 3) and a device (1) characterized in that it can be shut off using a bleeder / flare valve (9) arranged below the mixing tube (5).   A device (1) with variable opening cross-section for extracting / flaring the combustible gas (2) according to claim 9, wherein the bleeder / flare valve (9) comprises two compartments (9a, 9b) A device (1) comprising at least one float cup (9a, 9b), wherein the compartments (9a, 9b) are opened, controlled and closed independently of each other.   11. A method for a crude gas (2) combustion using a device (1) according to any one of claims 1 to 10, wherein the baffle has a variable cross-section with an inlet pressure and / or a discharge rate of the extracted gas. A method characterized by being adjusted by (6).   12. The method for combustion of crude gas (2) according to claim 11, wherein the ratio of the cross section of the gas supply pipe (3) and the inner pipe (4) and the inner pipe (4) and the mixing pipe (5). The reduction in the amount of air supplied to the inner pipe (4) results in a combustion air ratio below the stoichiometry in the inner pipe (4), and the mixing pipe (5) and the inner pipe ( 4) characterized in that a proportional increase in the amount of air supplied to the mixing tube (5) via the annular gap between 4) is chosen to give a combustion air ratio above the stoichiometry above the inner tube (4). how to.   13. A method for combustion of crude gas (2) according to claim 11 or 12, wherein the discharge rate of the extracted / flared leaking gas (2) remains constant during bleed-off / flaring. Feature method.   14. A method for combustion of a crude gas (2) according to any one of claims 11 to 13, wherein an inert gas (12a) is the gas supply pipe (3), the inner pipe (4) or the mixture. A method characterized in that it is fed into a tube (5).   15. A method for burning crude gas (2) according to claim 14, characterized in that the inert gas (12a) is water vapor.   15. A method for combustion of a crude gas (2) according to claim 14, characterized in that the inert gas (12a) is a mixture of water vapor and extracted / flared combustion gas.   17. A method for the combustion of a crude gas (2) according to any one of claims 14 to 16, characterized in that the inert gas (12a) is supplied at a pressure of 7 to 15 bar.   18. A method for the combustion of crude gas (2) according to any one of claims 11 to 17, wherein the two compartments of the float cup (9a, 9b) of the bleeder / flare valve (9) are synchronized. A method characterized in that it can be opened, controlled or closed by a pneumatic cylinder.

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