JP6981053B2 - Hydrogen combustion boiler - Google Patents

Description

The present invention relates to a hydrogen combustion boiler.

Conventionally, a hydrogen combustion boiler that uses hydrogen gas as a fuel is known. Hydrogen-burning boilers are attracting attention because they do not generate carbon dioxide when fuel is burned.

On the other hand, hydrogen gas, which is a fuel, has a faster combustion speed than hydrocarbon gas and has a wide combustion range when mixed with air, so it is necessary to prevent the flame generated by the burner from flowing back to the hydrogen supply line. There is. Therefore, a system has been proposed in which a flashback prevention device (hereinafter referred to as a frame arrester) for preventing backflow of flame is arranged in a hydrogen supply line for supplying hydrogen (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-108832

In the system proposed in Patent Document 1, the frame arrester digests the flame when the flame flows back from the burner to the hydrogen supply line. This makes it possible to prevent the flame from reaching the hydrogen supply line on the primary side of the position where the frame arrester is arranged.

By the way, in the hydrogen combustion boiler, when hydrogen gas is supplied to both the main burner and the pilot burner, a flashback occurs in both the line supplying hydrogen gas to the main burner and the line supplying hydrogen gas to the pilot burner. Can be considered. Therefore, by arranging frame arresters individually corresponding to each of the line for supplying hydrogen gas to the main burner and the line for supplying hydrogen gas to the pilot burner, any flashback can be prevented. On the other hand, since the frame arrester is very expensive, the increase in the number of frame arresters to be arranged is a factor that increases the manufacturing cost of the hydrogen combustion boiler.

Therefore, an object of the present invention is to provide a hydrogen combustion boiler that can suppress the manufacturing cost while ensuring safety when hydrogen gas is supplied to both the main burner and the pilot burner.

The present invention includes a main fuel line that supplies hydrogen gas as fuel, a frame arrester attached to the main fuel line, a first pilot line that branches from the downstream side of the frame arrester in the main fuel line, and the main. The present invention relates to a hydrogen combustion boiler including a main burner connected to the downstream side of the fuel line and a pilot burner connected to the downstream side of the first pilot line.

Further, the hydrogen combustion boiler is arranged on the upstream side of the frame arrester and on the downstream side of the branch position of the first pilot line in the main fuel line and the second pilot line that joins the main fuel line. It further includes one shutoff valve, a second shutoff valve arranged on the upstream side of the confluence position of the second pilot line in the main fuel line, and a third shutoff valve arranged on the second pilot line. Is preferable.

Further, the hydrogen combustion boiler is connected between the throttle member arranged on the downstream side of the third shutoff valve in the second pilot line and the third shutoff valve and the throttle member in the second pilot line. It is preferable to further provide a purge line for supplying the inert gas.

Further, it is preferable that the second shutoff valve is arranged on the upstream side immediately close to the confluence position of the second pilot line in the main fuel line.

Further, it is preferable that the main burner includes a main nozzle from which hydrogen gas is ejected, and the pilot burner includes a pilot nozzle having a diameter smaller than that of the main nozzle.

According to the present invention, when hydrogen gas is supplied to both the main burner and the pilot burner, it is possible to provide a hydrogen combustion boiler that can suppress the manufacturing cost while ensuring safety.

It is a figure which shows typically the structure of the hydrogen combustion boiler which concerns on one Embodiment of this invention. It is a schematic diagram which shows the burner of the hydrogen combustion boiler of one Embodiment. It is the A arrow view of FIG.

Hereinafter, the hydrogen combustion boiler 1 according to the embodiment of the present invention will be described with reference to the drawings.
The hydrogen combustion boiler 1 of the present embodiment is a boiler that uses hydrogen gas G1 as fuel. The hydrogen combustion boiler 1 is, for example, a once-through boiler, and hydrogen gas G1 is supplied to both the main burner 10 and the pilot burner 20 as fuel to the hydrogen combustion boiler 1. A frame arrester 30 is arranged in the line for supplying the hydrogen gas G1 to the main burner 10 and the pilot burner 20, and prevents the flame from propagating to the line for supplying the hydrogen gas G1 from the main burner 10 and the pilot burner 20.

As shown in FIGS. 1 to 3, the hydrogen combustion boiler 1 includes a can body T, a main burner 10, a pilot burner 20, and a control unit 50. Further, as shown in FIG. 1, the hydrogen combustion boiler 1 includes a main fuel line L100, a frame arrester 30 arranged in the main fuel line L100, a first pilot line L110, a second pilot line L120, and the like. A purge line L130 and the like are provided. As used herein, the term "line" is a general term for channels, routes, pipelines, and the like.

The can body T includes a lower header, a plurality of water pipes, an upper header (none of which is shown), a combustion chamber B, and the like, and heats the water supplied to the can body T to generate steam. ..
The main burner 10 is arranged on the can body T. The main burner 10 burns hydrogen gas G1 in the combustion chamber B of the can body T. As shown in FIGS. 2 and 3, the main burner 10 includes a main nozzle 11 and a burner head 12.

The main nozzle 11 is formed in a tubular shape, and the tip portion thereof is arranged toward the combustion chamber B inside the can body T. The base end portion of the main nozzle 11 is connected to the downstream end portion of the main fuel line L100, which will be described later.

The burner head 12 is connected to the tip of the main nozzle 11. The burner head 12 has a shape whose diameter is expanded from the tip of the main nozzle 11. A plurality of through holes 13 are formed on the side surface of the burner head 12.

The pilot burner 20 is arranged on the can body T as shown in FIG. The pilot burner 20 ignites the main burner 10. As shown in FIGS. 2 and 3, the pilot burner 20 includes a pilot nozzle 21, an electrode rod 22, and a connecting member 23.

The pilot nozzle 21 is formed in a tubular shape having a diameter smaller than that of the main nozzle 11, and the tip portion thereof is arranged in the vicinity of the tip portion of the main nozzle 11. The tip portion of the pilot nozzle 21 is arranged inside the main nozzle 11, and the base end portion penetrates the side wall of the main nozzle 11 and is exposed from the outer peripheral surface of the main nozzle 11. At the base end of the pilot nozzle 21, a connecting member 23 for connecting to the first pilot line L110, which will be described later, is arranged. The base end portion of the pilot nozzle 21 is connected to the downstream side of the first pilot line L110, which will be described later.

The electrode rod 22 is an ignition device that ignites the pilot burner 20, and is arranged near the tip of the pilot nozzle 21.
The connecting member 23 is a member for connecting the pilot nozzle 21 and the downstream end of the first pilot line L110, which will be described later.

The main fuel line L100 supplies hydrogen gas G1 as fuel to the main burner 10. The upstream side of the main fuel line L100 is connected to a supply source (not shown) of hydrogen gas G1. The downstream side of the main fuel line L100 is connected to the base end portion of the main burner 10. The main fuel line L100 includes an upstream line L101 and a downstream line L103.

The upstream line L101 is a line located on the upstream side of the main fuel line L100, and the upstream side is connected to a hydrogen gas G1 supply source (not shown). A frame arrester 30, which will be described later, is connected to the downstream side of the upstream line L101.

The downstream line L103 is a line located on the downstream side of the main fuel line L100, and the upstream side is connected to the frame arrester 30. The downstream side of the downstream side line L103 is connected to the main burner 10.

The frame arrester 30 is attached to the main fuel line L100. The frame arrester 30 prevents the flame from propagating upstream.

In the above main fuel line L100, a first shutoff valve V11, a first ball valve V61, a second shutoff valve V21, V22, and a flow rate adjusting valve V51 are arranged.

The first shutoff valve V11 is arranged on the downstream side (downstream side line L103) of the frame arrester 30 in the main fuel line L100. The first shutoff valve V11 is composed of a solenoid valve and opens or closes the downstream line L103. The first shutoff valve V11 is composed of, for example, a normally open (NO) type solenoid valve, and is appropriately closed by being controlled from a constantly open state.

The first ball valve V61 is arranged on the upstream side of the first shutoff valve V11 in the downstream line L103. The first ball valve V61 is manually operated to open or close the downstream line L103.

The second shutoff valves V21 and V22 are arranged on the upstream line L101. In the present embodiment, the second shutoff valves V21 and V22 are arranged on the immediately upstream side of the connection position (merging position) of the second pilot line L120 described later in the main fuel line L100. The second shutoff valves V21 and V22 are composed of solenoid valves and open or close the upstream line L101.

The flow rate adjusting valve V51 is arranged on the upstream side of the second shutoff valves V21 and V22 in the upstream line L101. The flow rate adjusting valve V51 adjusts the flow rate of the hydrogen gas G1 flowing through the main fuel line L100.

The first pilot line L110 is a line branching from the main fuel line L100, and supplies hydrogen gas G1 as fuel to the pilot burner 20. The first pilot line L110 branches from the downstream side of the frame arrester 30 in the main fuel line L100. In the present embodiment, the first pilot line L110 branches from between the frame arrester 30 and the first ball valve V61 in the main fuel line L100.
The downstream side of the first pilot line L110 is connected to the base end portion (connecting member 23) of the pilot burner 20. The first pilot line L110 is configured to have a smaller diameter than the main fuel line L100.

A second ball valve V71 is arranged on the first pilot line L110. The second ball valve V71 is manually operated to open or close the first pilot line L110.

The second pilot line L120 joins the main fuel line L100 on the upstream side of the frame arrester 30. In the present embodiment, the second pilot line L120 is configured as a line that bypasses the upstream line L101, branches from between the flow rate adjusting valve V51 and the second shutoff valve V21 in the upstream line L101, and the second shutoff. It joins the main fuel line L100 (upstream line L101) in the immediate vicinity of the second shutoff valve V22 between the valve V22 and the frame arrester 30. The second pilot line L120 is configured to have a smaller diameter than the main fuel line L100.

The third shutoff valves V31 and V32 and the throttle member 40 are arranged on the second pilot line L120.
The third shutoff valves V31 and V32 are arranged on the second pilot line L120. The third shutoff valves V31 and V32 are composed of solenoid valves, and open or close the second pilot line L120.
The throttle member 40 is arranged on the downstream side of the third shutoff valve V32 in the second pilot line L120. The throttle member 40 throttles the flow rate of the gas flowing through the second pilot line L120.

The purge line L130 is connected between the third shutoff valve V32 in the second pilot line L120 and the throttle member 40. The upstream side of the purge line L130 is connected to the source of the inert gas G2 (not shown), and the downstream side is connected to the second pilot line L120. The purge line L130 supplies the inert gas G2 to the second pilot line L120.

A fourth shutoff valve V41 is arranged in the purge line L130. The fourth shutoff valve V41 is composed of a solenoid valve and opens or closes the purge line L130.

The control unit 50 opens / closes the flow rate adjusting valve V51, ignites the pilot burner 20, opens / closes the first shutoff valve V11, the second shutoff valves V21, V22, the third shutoff valves V31, V32, the fourth shutoff valve V41, and the like. It is a control device that is electrically controlled.

Next, the operation of the hydrogen combustion boiler 1 will be described.
When starting the combustion of the pilot burner 20, the control unit 50 opens the third shutoff valves V31 and V32 with the first shutoff valves V11, the second shutoff valves V21 and V22 and the fourth shutoff valves V41 closed. Then, the hydrogen gas G1 flows from the supply source (not shown) of the hydrogen gas G1 through the frame arrester 30 after flowing through the second pilot line L120, and then is ejected from the pilot nozzle 21 through the first pilot line L110. Further, the control unit 50 controls the electrode rod 22 to ignite the hydrogen gas G1 ejected from the pilot nozzle 21. As a result, combustion of the pilot burner 20 is started.

When the combustion of the main burner 10 is started after the combustion of the pilot burner 20 is started, the control unit 50 first opens the second shutoff valves V21 and V22. As a result, the hydrogen gas G1 also circulates in the upstream line L101 having a diameter larger than that of the second pilot line L120, and the flow rate of the hydrogen gas G1 flowing in the first pilot line L110 increases. As the flow rate of the hydrogen gas G1 flowing through the first pilot line L110 increases, the flame of the pilot burner 20 becomes larger.

Next, the control unit 50 opens the first shutoff valve V11. By opening the first shutoff valve V11, the hydrogen gas G1 is supplied to the main burner 10 through the downstream line L103, and the hydrogen gas G1 is ejected from the main nozzle 11. The hydrogen gas G1 ejected from the main nozzle 11 is ignited by the flame of the pilot burner 20. As a result, combustion of the main burner 10 is started. After that, the control unit 50 closes the third shutoff valves V31 and V32.
As described above, by increasing the flow rate of the hydrogen gas G1 flowing through the first pilot line L110 before igniting the main burner 10 to increase the flame of the pilot burner 20, the oxygen concentration in the vicinity of the burner decreases. In this state, by opening the first shutoff valve V11 and supplying the hydrogen gas G1 to the main burner 10, it is possible to prevent flashback from occurring when the main burner 10 is ignited.

Next, when stopping the combustion of the main burner 10, the control unit 50 closes the second shutoff valves V21 and V22. When the second shutoff valves V21 and V22 are closed while the third shutoff valves V31 and V32 are closed, the supply of hydrogen gas G1 to the downstream line L103 and the first pilot line L110 is stopped, and the main burner. Combustion of 10 (and pilot burner 20) is stopped.

After the combustion of the main burner 10 is stopped, the inert gas G2 is used to purge the hydrogen gas G1 remaining on the downstream side of the second shutoff valve V22 and the third shutoff valve V32. In this case, the control unit 50 closes the second shutoff valves V21, V22 and the third shutoff valves V31, V32, and opens the fourth shutoff valve V41 with the first shutoff valve V11 open. By opening the fourth shutoff valve V41, the inert gas G2 is supplied from the purge line L130 to the second pilot line L120. The flow rate of the inert gas G2 flowing through the second pilot line L120 is throttled by the throttle member 40. The inert gas G2 whose flow rate is throttled by the throttle member 40 flows to the main fuel line L100 (upstream line L101) having a diameter larger than that of the second pilot line L120, and is ejected from the main burner 10. Further, a part of the inert gas G2 passes through the first pilot line L110 and is ejected from the pilot burner 20. As a result, the downstream side of the second shutoff valve V22 and the third shutoff valve V32 is purged by the inert gas G2.

According to the hydrogen combustion boiler 1 of the present embodiment described above, the following effects are obtained.
(1) A first pilot line that branches the hydrogen combustion boiler 1 from the main fuel line L100, the frame arrester 30 attached to the main fuel line L100, and the downstream side (main fuel downstream side line L103) of the frame arrester 30. It includes L110, a main burner 10 connected to the main fuel line L100, and a pilot burner 20 connected to the first pilot line L110. As a result, when a flashback occurred from the main burner 10 to the downstream side of the main fuel line L100 (main fuel downstream side line L103), and / or a flashback occurred from the pilot burner 20 to the first pilot line L110. Even in this case, one frame arrester 30 can extinguish the fire and prevent the propagation of the flame on the upstream side. Therefore, the manufacturing cost of the hydrogen combustion boiler 1 that supplies the hydrogen gas G1 to both the main burner 10 and the pilot burner 20 can be suppressed while ensuring safety.

(2) From the branch position (connection position) of the second pilot line L120, which joins the hydrogen combustion boiler 1 to the main fuel line L100 on the upstream side of the frame arrester 30, and the first pilot line L110 in the main fuel line L100. The first shutoff valve V11 arranged on the downstream side, the second shutoff valves V21 and V22 arranged on the upstream side of the confluence position (connection position) of the second pilot line L120 in the main fuel line L100, and the second pilot. The third shutoff valves V31 and V32 arranged on the line L120 were included. As a result, the pilot burner 20 can be burned by opening the third shutoff valves V31 and V32 with the first shutoff valves V11 and the second shutoff valves V21 and V22 closed, and then the first shutoff valve. By further opening V11 and the second shutoff valves V21 and V22, the main burner 10 and the pilot burner 20 can be burned. Further, by arranging the second shutoff valves V21, V22 and the third shutoff valves V31, V32 on the upstream side of the frame arrester 30, even if a flashback occurs, the second shutoff valves V21, V22 and Damage to the third shutoff valves V31 and V32 due to flashback can be prevented.

(3) The hydrogen combustion boiler 1 is connected between the throttle member 40 arranged on the downstream side of the third shutoff valves V31 and V32 and the third shutoff valves V31 and V32 and the throttle member 40 in the second pilot line L120. The purge line L130 to be used is included in the configuration. Thereby, by supplying the inert gas G2 from the upstream side of the drawing member 40, the flow rate of the inert gas G2 used for purging can be reduced, and the flow rate of the inert gas G2 can be optimized.

(4) The second shutoff valves V21 and V22 were arranged on the upstream side of the main fuel line L100 immediately near the confluence position of the second pilot line L120. As a result, the inert gas G2 supplied from the purge line L130 can suitably purge the downstream side of the second shutoff valves V21 and V22 of the main fuel line L100.

(5) The diameter of the pilot nozzle 21 was set to be smaller than the diameter of the main nozzle 11. As a result, the flow velocity of the hydrogen gas G1 in the pilot nozzle 21 can be increased, so that it is possible to prevent a flashback phenomenon from occurring in the first pilot line L110 when the main burner is ignited or burned.

Although the preferred embodiment of the hydrogen combustion boiler of the present invention has been described above, the present invention is not limited to the above-described embodiment and can be appropriately modified.

For example, in the above embodiment, the hydrogen gas G1 is supplied to the main burner 10 and the pilot burner 20 by providing the second pilot line L120 and opening and closing the second shutoff valves V21 and V22 and the third shutoff valves V31 and V32. Controlled, but not limited to this. For example, instead of providing the second pilot line L120 and the third shutoff valves V31 and V32, a fourth shutoff valve (solenoid valve, not shown) is arranged on the first pilot line L110 in place of the third shutoff valves V31 and V32. The purge line L130 may be connected between the second shutoff valve V22 in the main fuel line L100 and the frame arrester 30. Then, the first pilot line L110 may be opened and closed by opening and closing the fourth shutoff valve (not shown).

1 Hydrogen combustion boiler 10 Main burner 11 Main nozzle 20 Pilot burner 21 Pilot nozzle 30 Frame arrester 40 Aperture member L100 Main fuel line L110 1st pilot line L120 2nd pilot line L130 Purge line V11 1st shutoff valve V21, V22 2nd shutoff Valves V31, V32 3rd shutoff valve

Claims (4)

The main fuel line that supplies hydrogen gas as fuel,
The frame arrester attached to the main fuel line and
The first pilot line branching from the downstream side of the frame arrester in the main fuel line,
A second pilot line that branches on the upstream side of the main fuel line and joins the main fuel line on the upstream side of the frame arrester.
A second shutoff valve located upstream of the merging position of the second pilot line in the main fuel line,
The third shutoff valve arranged in the second pilot line and
The main burner connected to the downstream side of the main fuel line and
A pilot burner connected to the downstream side of the first pilot line is provided.
The second shutoff valve is a hydrogen combustion boiler arranged on the immediate upstream side of the confluence position of the second pilot line in the main fuel line. The hydrogen combustion boiler according to claim 1, further comprising a first shut-off valve disposed on the downstream side of the branch position of the first pilot line in the main fuel line. A throttle member arranged on the downstream side of the third shutoff valve in the second pilot line, and
The hydrogen combustion boiler according to claim 1 or 2, further comprising a purge line connected between the third shutoff valve and the throttle member in the second pilot line to supply an inert gas. The main burner includes a main nozzle from which hydrogen gas is ejected.
The hydrogen combustion boiler according to any one of claims 1 to 3 , wherein the pilot burner includes a pilot nozzle having a diameter smaller than that of the main nozzle.

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