JP2016186395A - Conveying apparatus and gas back flow suppression method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveying apparatus and a gas back flow suppression method capable of further suppressing a back flow of gas.SOLUTION: A conveying apparatus 2 and a gas back flow suppression method can suppress a back flow of gas from a side of a combustion furnace 1 by supplying a seal gas A2 or a pressurized gas A3 by a pressure state adjustment part 25 and hence adjusting a state of pressure within a path 5 of conveyance. In addition, a gas back flow suppression part 6 supplies a purge gas A4 to the path 5 of conveyance at a downstream side of the path 5 of conveyance from the pressure state adjustment part 25. Thus, gas supplied to the path 5 of conveyance collides with gas flowing back from the side of the combustion furnace 1, thereby damming a back flow of gas from the side of the combustion furnace 1. From the above, the back flow of gas can be suppressed further.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transport apparatus and a gas backflow suppression method.

  2. Description of the Related Art Conventionally, a transport device having a transport path for supplying fuel to a combustion furnace is known. For example, the circulating fluidized bed boiler described in Patent Document 1 describes that fuel is supplied from a fuel input device to a furnace through a fuel input port provided in the furnace.

JP 2012-255612 A

  By the way, in the transfer device described above, it is necessary to suppress the backflow of gas from the combustion furnace side to the upstream side. Therefore, it is conceivable to reduce the amount of gas flowing backward by providing a rotary valve in the transport path and supplying a gas for sealing the transport path.

  However, in a transport apparatus having only such a configuration, the amount of gas flowing backward cannot be sufficiently reduced, and a fuel that is easy to burn (for example, a fuel whose volatile matter is easily separated at a low temperature) is used as the fuel for the circulating fluidized bed boiler. Difficult to use. For this reason, it has been desired to further suppress the backflow of gas from the combustion furnace side in the transfer device.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a transport apparatus and a gas backflow suppression method that can further suppress the backflow of gas.

  A conveying apparatus according to the present invention includes a pressure state adjusting unit that adjusts a pressure state in a conveying path by supplying gas in a conveying apparatus that includes a conveying path for supplying fuel to a combustion furnace, and a pressure state adjusting A gas backflow suppression unit that supplies gas to the conveyance path on the downstream side of the conveyance path.

  In addition, the gas backflow suppression method according to the present invention supplies a gas, adjusts the state of pressure in the conveyance path for supplying fuel to the combustion furnace, and conveys more than the part to which the gas is supplied. On the downstream side of the gas, gas is supplied to the conveyance path.

  In the transfer apparatus and the gas backflow suppressing method according to the present invention, the gas is supplied by the pressure state adjusting unit, whereby the pressure state in the transfer path is adjusted and the backflow of gas from the combustion furnace side can be suppressed. In addition to this, gas is supplied to the conveyance path by the gas backflow suppression unit on the downstream side of the conveyance path from the pressure state adjustment unit. Thereby, when the gas supplied to the conveyance path collides with the gas flowing backward from the combustion furnace side, the reverse flow of the gas from the combustion furnace side can be blocked. In addition, since gas is supplied by the gas backflow suppression unit on the downstream side of the conveyance path from the part to which the gas is supplied by the pressure state adjustment unit (that is, the part without the pressure state adjustment part between the pressure and the combustion furnace). Even if the gas backflow suppression unit is used in combination with the pressure state adjustment unit, the effect of the gas backflow suppression unit can be suitably achieved. As described above, since the gas can be supplied by two systems of the pressure state adjusting unit and the gas backflow suppressing unit, the backflow of gas can be further suppressed.

  In the transport apparatus according to the present invention, the gas backflow suppression unit may supply gas to the transport path toward the downstream side of the transport path. With such a configuration, the gas supplied to the conveyance path has a flow toward the downstream side of the conveyance path, so that the backflow of gas from the combustion furnace side can be more reliably blocked. For this reason, the backflow of gas can be further suppressed.

  In the transport apparatus according to the present invention, the transport path may include a dust collector that ventilates the transport path, and the gas backflow suppression unit may supply gas to the transport path on the downstream side of the transport path from the dust collector. In the above configuration, the dust collector ventilates the conveyance path and removes dust in the conveyance path. As a result, even if flammable gas or flammable dust or the like enters the transport path, these are removed by the dust collector, and safety in the transport path is ensured. Further, the gas backflow suppression unit supplies gas to the conveyance path on the downstream side of the dust collector, so that the backflow of gas from the combustion furnace side can be further suppressed.

  In the transport device according to the present invention, the gas supplied to the transport path by the gas backflow suppression unit may be air. In this case, since the gas supplied to the conveyance path by the gas backflow suppressing unit can be used as air for burning the fuel, it is easy to adjust the total amount of air supplied to the combustion furnace. For this reason, a suitable combustion state can be maintained in the combustion furnace.

  According to the present invention, the backflow of gas can be further suppressed.

It is a schematic block diagram which shows the circulating fluidized bed boiler provided with the conveying apparatus which concerns on embodiment. It is the schematic which shows the ejection part which concerns on the conveying apparatus of FIG. It is the schematic which shows the ejection part which concerns on a modification. It is the schematic which shows the ejection part which concerns on another modification. It is a schematic block diagram which shows the circulating fluidized bed boiler which has a dust collector.

  Hereinafter, an embodiment of a transfer device and a gas backflow suppression method according to the present invention will be described in detail with reference to the accompanying drawings.

  A circulating fluidized bed boiler 100 shown in FIG. 1 is a device that burns fuel F and generates steam by heat generated by the combustion. In the circulating fluidized bed boiler 100, for example, various non-fossil fuels (biomass, waste tires, waste plastic, sludge, etc.) can be used as the fuel F. In particular, the volatile components are separated at, for example, about 200 ° C. Even the fuel can be suitably used as the fuel F. The steam generated in the circulating fluidized bed boiler 100 is used for driving a power generation turbine (not shown), for example. Such a circulating fluidized bed boiler 100 includes a combustion furnace 1 and a transfer device 2.

  The combustion furnace 1 is a furnace for burning the fuel F by causing a mixture of the fuel F and the fluid medium M to flow at a high temperature. In the combustion furnace 1, a fluid medium M such as silica sand is accommodated. The combustion furnace 1 is formed with a fuel inlet 3 for introducing fuel F and a combustion air inlet 4 for injecting combustion air A1. Ordinary air can be used as the combustion air A1.

  The combustion air A <b> 1 is blown into the combustion furnace 1 to flow the mixture of the fuel F and the fluid medium M and is used for combustion of the fuel F. Thus, since the combustion air A1 is blown into the combustion furnace 1, the pressure in the combustion furnace 1 becomes higher than the atmospheric pressure.

  The conveying device 2 is a device that conveys the fuel F and throws it into the combustion furnace 1 while suppressing the backflow of gas from the combustion furnace 1 side. The conveying device 2 is configured to include a conveying path 5 for supplying the fuel F to the combustion furnace 1, and gas backflow suppression that suppresses the backflow of gas from the combustion furnace 1 side to the upstream side (that is, the side opposite to the combustion furnace 1). Part 6 and a pressure state adjusting part 25 for adjusting the state of the pressure in the conveying path 5.

  The conveyance path 5 is connected to the fuel delivery section 7 that sends out the fuel F to the conveyance path 5 on the upstream side, and is connected to the fuel input port 3 of the combustion furnace 1 on the downstream side. Specifically, the conveyance path 5 includes a first pipeline 8 connected to the fuel delivery unit 7, a second pipeline 9 provided on the downstream side of the first pipeline 8, and a downstream of the second pipeline 9. And a fuel input path 10 connected to the combustion furnace 1.

  The first pipe 8 conveys the fuel F sent from the fuel delivery unit 7 to the downstream side. The second conduit 9 conveys the fuel F from the first conduit 8 to the fuel input passage 10. The 1st pipe line 8 and the 2nd pipe line 9 are tubular channel | paths, for example, it is good also as a structure which conveys the fuel F with the conveyor etc. which were provided in the inside.

  The pressure state adjusting unit 25 adjusts the state of the pressure in the transport path 5 by supplying gas, thereby suppressing the backflow of gas from the combustion furnace 1 side. Here, as a method for adjusting the state of the pressure in the conveyance path 5, a technique for cutting off the pressure in the first pipe 8 and in the combustion furnace 1, in the fuel input path 10, and in the second pipe 9 (for example, And a method using the rotary valve 11 described below) and a method for increasing the pressure in the transport path 5 (for example, a method using the pressurizing means 26 described below). The pressure state adjustment unit 25 includes the rotary valve 11 and the pressurizing unit 26. Note that the pressure state adjustment unit 25 may include only one of the rotary valve 11 and the pressurizing unit 26. Alternatively, the pressure state adjustment unit 25 may not be provided in the transport device 2. In addition, the pressure state adjusting unit 25 is not limited to the rotary valve 11 and the pressurizing unit 26 as long as it has the above-described function. That is, as long as the pressure in the first pipe 8 and the combustion furnace 1, the fuel input path 10, the second pipe 9 is cut off, or the pressure in the transport path 5 is increased, any It can be configured.

  The rotary valve 11 is provided between the first pipe line 8 and the second pipe line 9, and the backflow of gas from the combustion furnace 1 side to the upstream side is caused by pressure loss between the upstream side and the downstream side thereof. Suppress. The rotary valve 11 generates pressure loss by both the effect of sealing by a mechanical structure and the effect of sealing by supplied gas, and suppresses the backflow of gas.

  An example of a seal having a mechanical structure of the rotary valve 11 will be described. The rotary valve 11 includes a casing 15 and a rotor 16. In the rotary valve 11, the gap between the tip of the blade 16 a of the rotor 16 and the inner surface of the casing 15 is formed so as to be very narrow compared to the distance between the mutually facing inner surfaces of the transport path 5. As a result, if the gas tries to flow backward in the transport path 5, the reverse flow is suppressed by the pressure loss when passing through the rotary valve 11. With such a configuration, the rotary valve 11 suppresses the backflow of gas by the effect of sealing by a mechanical structure.

  An example of sealing with gas supplied to the rotary valve 11 will be described. The rotary valve 11 discharges a conveyed product by rotating a rotor 16 having a plurality of blades 16a radially attached in a cylindrical casing 15. At this time, the non-opening portion (entrance / exit of the casing 15) is discharged. A plurality of blades 16a are always present in the closed side of the removed side), and the pressure in the casing 15 is changed to the sealing gas A2 by the sealing gas (gas) A2 from the sealing gas line 17a connected to the rotary valve 11. By supporting and maintaining the pressure, and sealing the upstream and downstream, the backflow of gas from the combustion furnace 1 side to the upstream side is further suppressed. With such a configuration, the rotary valve 11 suppresses the backflow of gas by the effect of sealing by the supplied sealing gas A2. The seal gas A2 will be described later. The seal gas line 17a includes a flow rate adjusting unit 20 that adjusts the flow rate of the circulating seal gas A2, and a pressure gauge 21 that measures the pressure of the seal gas A2. For example, a butterfly valve or the like can be used as the flow rate adjusting unit 20.

  The rotor 16 is disposed in the casing 15 and is rotationally driven by a rotational drive mechanism (not shown). As a result, the fuel F that has been transported through the first conduit 8 and reaches the rotary valve 11 is transported to the second conduit 9 by the blade 16 a of the rotor 16.

  The pressurizing means 26 supplies a pressurized gas (gas) A3 such as air into the first pipeline 8. Thereby, the inside of the 1st pipe line 8 is pressurized, and since the pressure difference between the combustion furnace 1 side and the 1st pipe line 8 becomes small, the backflow of the gas from the combustion furnace 1 side to an upstream side is suppressed.

  Since the pressure in the combustion furnace 1 is higher than the atmospheric pressure as described above, the pressure on the combustion furnace 1 side of the transport path 5 is higher than the atmospheric pressure.

  The fuel input passage 10 is a tubular passage. The downstream end of the fuel input path 10 is connected to the fuel input port 3 of the combustion furnace 1. A screw conveyor 13 is installed inside the fuel input path 10. The screw conveyor 13 extends from the vicinity of the boundary between the second pipe line 9 and the fuel input path 10 to the vicinity of the fuel input port 3 of the combustion furnace 1. With such a configuration, the fuel F from the second pipeline 9 is conveyed downstream by the rotation of the screw conveyor 13 and is fed into the combustion furnace 1 through the fuel inlet 3. The fuel input path 10 is provided with a thermometer 14 for monitoring the combustion state in the combustion furnace 1 by measuring the temperature inside.

  As described above, the fuel input path 10 is connected to the combustion furnace 1. For this reason, the fuel input path 10 is heated by the heat generated by the combustion of the fuel F in the combustion furnace 1. And the fuel F in the middle of being conveyed in the screw conveyor 13 of the fuel injection path 10 by this is also heated. At this time, in particular, when a fuel F having a volatile component separated at a low temperature is used, the volatile component separated from the fuel F in the screw conveyor 13 is released as a combustible gas (gas) G1. In addition to the combustible gas G1 released in this way, combustible gas (gas) G2 is released by the combustion of the fuel F in the combustion furnace 1. These gases are referred to as “gas from the combustion furnace 1 side”. The gas from the combustion furnace 1 side may flow backward in the conveyance path 5 from the combustion furnace 1 side to the upstream side. The gas from the combustion furnace 1 side may be either one of the combustible gas G1 or the combustible gas G2, or may be both.

  The gas backflow suppression unit 6 includes a line 17 through which gas flows, a gas delivery unit 18 that sends gas to the line 17, and an ejection unit 22 that ejects gas to the transport path 5. The line 17 is branched into the sealing gas line 17a and the purge gas line 17b. Of the gases delivered from the gas delivery unit 18, the gas that is diverted to the seal gas line 17a side is also referred to as seal gas A2, whereas the gas that is diverted to the purge gas line 17b side is purge gas (gas) A4. It will also be called. Here, normal air is used as the gas. Further, the line 17 is provided with a flow rate indicator 19 for detecting the flow rate of gas. The ejection part 22 is a supply port for supplying the purge gas A4 from the purge gas line 17b into the second pipeline 9.

  The purge gas line 17b is connected to the second pipeline 9 on the downstream side. Thus, the purge gas A4 that has flowed through the purge gas line 17b is supplied into the second pipe 9. The purge gas line 17b includes a flow rate adjusting unit 23 that adjusts the flow rate of the flowing purge gas A4, and a pressure gauge 24 that measures the pressure of the purge gas A4. As the flow rate adjusting unit 23, for example, a butterfly valve or the like can be used.

  The ejection part 22 defines the direction in which the purge gas A4 is supplied to the second pipeline 9. As shown in FIG. 2, here, the ejection portion 22 does not protrude from the inner wall surface of the second pipeline 9 and opens to the wall surface of the second pipeline 9. A purge gas line 17 b is connected to the second pipeline 9 along the direction toward the downstream side of the second pipeline 9. Specifically, it is preferable that the angle α between the direction toward the downstream side of the second conduit 9 and the direction in which the purge gas line 17b is directed toward the second conduit 9 is greater than 0 degree and less than 90 degrees. . However, the angle α is not limited to this range.

  Next, the operation of the transfer device 2 described above will be described.

  First, the fuel F in the screw conveyor 13 in the fuel input path 10 is heated by the heat generated by the combustion of the fuel F in the combustion furnace 1. At this time, when a fuel F that separates volatile components at a low temperature is used, the volatile components separated from the fuel F in the screw conveyor 13 are released as the combustible gas G1. In addition to the combustible gas G1 released in this manner, the combustible gas G2 is released by the combustion of the fuel F in the combustion furnace 1. Here, in order to flow the mixture of the fuel F and the fluid medium M in the combustion furnace 1, the combustion air A1 is blown into the combustion furnace 1, so that the pressure on the combustion furnace 1 side of the conveying path 5 is higher than the atmospheric pressure. It is high. On the other hand, the pressure in the first pipe line 8 at a position away from the combustion furnace 1 is lower than the pressure on the combustion furnace 1 side of the transport path 5. In this case, there is a possibility that gas from the combustion furnace 1 side flows back through the conveyance path 5 due to a pressure difference between the combustion furnace 1 side and the upstream side in the conveyance path 5.

  On the other hand, the pressurizing means 26 in the pressure state adjusting unit 25 suppresses the backflow of gas from the combustion furnace 1 side by supplying the pressurized gas A3 and increasing the pressure in the first conduit 8. it can. Further, the rotary valve 11 in the pressure state adjusting unit 25 supplies the sealing gas A2, and pressure is applied by both the sealing effect by the mechanical structure of the rotary valve 11 and the sealing effect by the sealing gas A2. By generating a loss and cutting off the pressure in the first pipe line 8 and the second pipe line 9, the backflow of gas from the combustion furnace 1 side can be suppressed.

  Further, in the transfer apparatus 2, the purge gas A4 supplied to the transfer path 5 is collided with the gas flowing backward from the combustion furnace 1 side, thereby blocking the reverse flow of the gas from the combustion furnace 1 side, so that the combustion furnace 1 The backflow of gas from the side can be suppressed. Specifically, in the transfer device 2, the purge gas A <b> 4 that has flowed through the purge gas line 17 b is supplied into the second pipe line 9 through the ejection portion 22. Thereby, since the flow which flows toward the downstream of the conveyance path 5 arises in the gas supplied to the conveyance path 5, the reverse flow of gas can be suppressed by blocking the reverse flow of the gas from the combustion furnace 1 side.

  Here, the ejection part 22 does not protrude from the inner wall surface of the second pipeline 9 and opens to the wall surface of the second pipeline 9. A purge gas line 17 b is connected to the second pipeline 9 along the direction toward the downstream side of the second pipeline 9. As a result, the gas supplied to the conveyance path 5 has a flow toward the downstream side of the conveyance path 5, so that the backflow of gas from the combustion furnace 1 side is more reliably blocked.

  The purge gas A4 supplied to the second pipeline 9 flows downstream through the transport path 5 and reaches the combustion furnace 1. Since the purge gas A4 is air, it is used in the combustion furnace 1 to burn the fuel F together with the combustion air A1. It is possible to easily adjust the total amount of air supplied to the combustion furnace 1 by adjusting the supply amount of the purge gas A4 by the flow rate adjusting unit 23 provided in the purge gas line 17b. Similarly, the same effect can be achieved by using air for the sealing gas A2 and the pressurized gas A3.

  As described above, in the transport device 2 and the gas backflow suppression method according to the present invention, the pressure gas in the transport path 5 is changed by supplying the seal gas A2 or the pressurized gas A3 by the pressure state adjusting unit 25. It is adjusted and the back flow of the gas from the combustion furnace 1 side can be suppressed. In addition to this, the purge gas A4 is supplied by the gas backflow suppression unit 6 to the downstream side of the transport path 5 from the portion where the pressure gas adjustment unit 25 supplies the seal gas A2. Thereby, the purge gas A4 supplied to the conveyance path 5 collides with the gas flowing backward from the combustion furnace 1 side, so that the reverse flow of the gas from the combustion furnace 1 side can be blocked. The purge gas A4 is supplied downstream of the part to which the seal gas A2 is supplied by the pressure state adjusting unit 25 (that is, the part not passing through the pressure state adjusting part 25 with the combustion furnace 1). Therefore, even if the gas backflow suppression unit 6 is used in combination with the pressure state adjustment unit 25, the effects of the gas backflow suppression unit 6 can be suitably achieved. As described above, since the gas can be supplied in two systems of the pressure state adjusting unit 25 and the gas backflow suppressing unit 6, the backflow of gas can be further suppressed.

  In the transport apparatus 2 according to the present invention, the gas backflow suppression unit 6 supplies the purge gas A4 to the transport path 5 toward the downstream side of the transport path 5. With such a configuration, the purge gas A4 supplied to the transport path 5 has a flow toward the downstream side of the transport path 5, so that the backflow of gas from the combustion furnace 1 side can be more reliably blocked. For this reason, the backflow of gas can be further suppressed.

  In the transfer device 2 according to the present invention, the purge gas A4 is air. In this case, since the purge gas A4 from the gas backflow suppression unit 6 can be used as the air for burning the fuel F, the total amount of air supplied to the combustion furnace 1 can be easily adjusted. For this reason, a suitable combustion state can be maintained in the combustion furnace 1.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, as shown in FIG. 3, the ejection portion 22 protrudes from the inner wall surface of the second conduit 9 to the inside of the second conduit 9 and is downstream at an angle β with respect to the extending direction of the second conduit 9. It may be bent toward the side, and its tip may be opened downstream. By doing so, the purge gas A4 can be guided toward the downstream side of the second pipe 9, so that the flow toward the downstream side of the transport path 5 can be generated more reliably. In this case, the angle β at which the ejection portion 22 bends is preferably larger than −90 degrees and smaller than 90 degrees. However, the angle β is not limited to this range.

  As shown in FIG. 4, the ejection portion 22 protrudes from the inner wall surface of the second pipeline 9 to the inner side of the second pipeline 9 and faces the upstream side of the second pipeline 9. The shape may be longer from the inner wall surface of the second conduit 9 than the wall portion 22b facing the downstream side. Even with such a configuration, the purge gas A4 can be caused to flow toward the downstream side of the second pipe 9.

  Further, as shown in FIG. 5, the transport path 5 has a dust collector 12 for ventilating the transport path 5 in the middle of the first pipeline 8, and the gas backflow suppression unit 6 is downstream of the transport path 5 from the dust collector 12. On the side, the purge gas A4 may be supplied to the transport path 5. In this case, the pressure state adjustment unit 25 does not have the pressurizing means 26. In the configuration as described above, the dust collector 12 ventilates the first pipeline 8 and removes dust in the first pipeline 8. As a result, even if a flammable gas or flammable dust or the like enters the first pipeline 8, they are removed by the dust collector 12, and safety in the first pipeline 8 is ensured. Is done. Here, when the inside of the conveyance path 5 is ventilated by the dust collector 12, the pressure in the conveyance path 5 is lowered, and in particular, the pressure in the first pipe line 8 may be lowered to about atmospheric pressure. In this case, the backflow of gas from the combustion furnace 1 side tends to occur easily. However, when the gas backflow suppression unit 6 supplies gas to the transport path 5 on the downstream side of the dust collector 12, the backflow of gas from the combustion furnace 1 side can be further suppressed.

  Further, the sealing gas line 17a and the purge gas line 17b may not be configured by branching the same line 17 in the middle, but may be configured as separate lines. In this case, separate gas delivery sections 18 are provided.

  The purge gas line 17 b is not particularly limited as long as the purge gas line 17 b is connected to the downstream side of the rotary valve 11 in the transport path 5. For example, the purge gas line 17 b may be connected to the fuel input passage 10 instead of being connected to the second conduit 9. Alternatively, the purge gas line 17 b may be connected to both the second pipe line 9 and the fuel input path 10.

  Further, the sealing gas A2, the pressurized gas A3, and the purge gas A4 are not limited to air, and for example, exhaust gas or the like may be used.

  DESCRIPTION OF SYMBOLS 1 ... Combustion furnace, 2 ... Conveyor device, 5 ... Conveyance path, 6 ... Gas backflow suppression part, 12 ... Dust collector, 25 ... Pressure state adjustment part, A2 ... Seal gas, A4 ... Purge gas, F ... Fuel.

Claims (5)

In a transfer device having a transfer path for supplying fuel to a combustion furnace,
A pressure state adjustment unit that adjusts the state of pressure in the transport path by supplying gas; and
And a gas backflow suppression unit that supplies gas to the conveyance path on the downstream side of the conveyance path from the pressure state adjustment unit.   The said gas backflow suppression part supplies gas to the said conveyance path toward the downstream of the said conveyance path, The conveying apparatus of Claim 1 characterized by the above-mentioned. The transport path has a dust collector for ventilating the transport path,
The said gas backflow suppression part supplies gas to the said conveyance path in the downstream of the said conveyance path from the said dust collector, The conveying apparatus of Claim 1 or 2 characterized by the above-mentioned.   The gas supplied to the said conveyance path by the said gas backflow suppression part is air, The conveying apparatus as described in any one of Claims 1-3 characterized by the above-mentioned.   Supplying gas and adjusting the state of pressure in the transport path for supplying fuel to the combustion furnace, and supplying gas to the transport path downstream of the part to which the gas is supplied Gas backflow suppression method.

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