JPS62102017A - Slurry fuel burning device - Google Patents

Abstract

PURPOSE:To cause no damage to constituting members for a burning device such as a cooling water pipe and carry out the start and stop of a burner with extremely reduced disturbance for heat absorbing characteristic by performing always optimum control with detecting change of temp. and inner fluid pressure in a burner gun and pipes supplying slurry fuel and medium for purge to the burner gun. CONSTITUTION:At the starting time of a burner, a three-way change-over valve 16 is opened at first to the side of medium making slurry and a water supply and adjusting valve 10 is closed. For a pressure controller 19, water flow rate necessary to cool a burner gun is previously set up and water flow rate is so adjusted as to reach this set value by the valve 10 and a pressure meter 2a measures actual water pressure to feed back its result. In order to confirm whether or not the burner gun is cooled to the temp. in which solidification of fuel does not occur even if slurry fuel is supplied, actual temp. of the burner gun is measured by a temp. switch 24 and when measured temp. comes to a specified value, the valve 16 is changed over from the medium supply side to the slurry fuel supply side.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a combustion device, and particularly to a slurry fuel combustion device that purges fuel in a burner while preventing misfires, rapid cooling, etc. in the furnace.

<Conventional technology> Due to changes in the fuel situation in large boilers for thermal power plants and other industrial combustion equipment, there is an active shift from petroleum-based fuels to other fuels, especially coal. .

As a method for improving the handling properties of coal, which is a solid fuel, slurry fuel, which is a mixture of atomized coal and liquid, has been developed and used. In particular, fuel that is a mixture of water and coal (CWM% Coal and Water Mix
tur) is attracting attention partly because it is economically superior. In order to handle this slurry fuel in the same manner as liquid fuel, not only is a handling system similar to that used for liquid fuel required, but also special consideration is required in consideration of the characteristics of slurry fuel.

In devices that burn slurry fuel, for fuels containing fine solid fuel particles such as CWM, a typical combustion method is a spray combustion method in which the slurry fuel is atomized by atomizing it with an atomizing medium such as steam. . FIG. 2 shows a conventional example of this spray combustion method.

In FIG. 2, a burner gun 1 having a combustion nozzle includes a pipe 5, a supply valve 8, a flexible hose 14
Slurry 2 is supplied via the.

On the outlet side of the supply valve 8, there are a pipe 7, a supply valve 10, and a check valve 1.
1, a slurrying medium 4 for burner gun purging is supplied. Further, a pressure gauge 12 is attached to the downstream side of the connecting portion of the slurry medium pipe 7 to the slurry pipe 5. On the other hand, the spraying medium 3 is supplied to the burner gun 1 through a separate piping 6, a supply valve 9, and a flexible hose 15, and is mixed with the slurry fuel in the burner gun or at its tip. Atomize the fuel. A pressure gauge 13 is arranged on the outlet side of the supply valve 9.

In an apparatus having the above configuration, for example, in a CWM, when heat is applied, water, which is a slurrying medium, evaporates and the fuel coagulates and solidifies. Therefore, when igniting the burner, water, which is a slurry forming medium, is first supplied to the burner gun 1 by opening the valve 10 before opening the slurry supply valve 8. Burner gun 1 is supplied with 300 liters of heat from inside the furnace and from around the gun.
It is heated by combustion air at a high temperature of about ℃.
This water supply provides cooling. In this state, by opening the supply valve 8, slurry fuel is supplied into the gun, and at the same time, by closing the valve IO, the supply of water is stopped, and steady operation is thereafter performed.

When stopping the burner, if you simply close the supply valve 8, the fuel remaining in the gun will be heated by the surrounding heat and the water will evaporate, solidify inside the burner and at the tip of the burner, and the burner will become blocked. I end up. For this purpose, the valve 8 is closed to cut off the supply of slurry fuel, and almost at the same time the valve 10 is opened to supply water, which is the slurrying medium 4, into the burner gun l, and the slurry fuel remaining in the burner gun is flushed into the reactor with this water. I purge it to prepare for the next operation.

<Problems of the Prior Art> The following problems have been pointed out in the conventional device having the above configuration, and a solution thereof is desired.

First, if the amount of water supplied for purging is small, the burner may not be cooled sufficiently or purge may take a long time. On the other hand, if too much water is supplied for purging, the temperature inside the combustion equipment may drop unnecessarily, or water may splash onto a specific part of the furnace, especially if this part is a cooling water pipe. The rapid cooling caused by this causes thermal stress, which can cause damage to the cooling water pipes and shorten their service life. Particularly when the operation of the burner is stopped and the slurry fuel is purged, the difference in viscosity between the slurry fuel and water becomes a big problem. In other words, the fuel remaining in the burner is pressurized and purged with water, but while slurry fuel has a viscosity of several hundred to 1000 cp, water has an extremely low viscosity of about lcp, and there is a gap between the two. There is a large difference in viscosity. Therefore, when the slurry fuel supply valve 8 is closed and the slurry medium supply valve 10 is opened to purge residual fuel, immediately after the valve 10 is opened, the inside of the burner gun 1 is entirely slurry fuel, so the high viscosity slurry fuel The pressure loss is large and the flow rate is relatively small even at high pressures. However, as the purge progresses in sequence, the purge reaches the tip of the burner gun, and when the last slurry fuel is purged, there is only low-viscosity water inside the gun, so the pressure loss rapidly decreases, and the high-pressure water suddenly drops. It will spew out into the furnace.

As a result, the gas temperature inside the furnace decreases, which adversely affects the combustion of other burners, causing disturbances to the heat absorption characteristics of the combustion equipment (boiler), and causing problems such as damage to the cooling water pipes as described above. .

<Objective of the present invention> The present invention was constructed in view of the above-mentioned problems, and it is possible to reduce disturbances in the heat absorption characteristics of the burner as much as possible without causing damage to combustion equipment components such as cooling water pipes. An object of the present invention is to provide a slurry combustion device that can be started and stopped.

<Summary of the Invention> In short, the present invention provides temperature and internal fluid pressure control for a burner gun that receives slurry fuel and a purging medium, and for a pipe line that supplies slurry fuel and a purging medium to this burner gun. This slurry combustion apparatus is equipped with a device for detecting changes, and is configured to perform optimal control at all times based on changes in the values to be detected.

<Example> An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, the slurry 2 includes a slurry pipe 5, a supply valve 8,
Slurry medium 3-way switching valve 16, flexible hose 1
4 and is supplied to the burner gun 1. A slurry medium 4 such as water is connected to a slurry medium pipe 7, a supply valve 10, and a check valve 1.
1 to the three-way switching valve 16. Further, a pressure gauge 12a is installed at the outlet of the three-way switching valve 16. On the other hand, atomizing medium 3 such as steam
is connected to a supply valve 9 via a pipe 6, and an adjustment valve 9 that can control the flow rate.
a, and is supplied to the burner gun 1. 13a is a pressure gauge with a transmitter provided at the outlet of the regulating valve 9a. 2
4 is a temperature switch placed at the tip of the burner gun 1, and this temperature switch 24 and pressure gauge 12a are connected to a timer 2.
3, and is further electrically connected via a pressure regulator 19 to an electric-air converter 21a for operating the medium supply valve 10. The spray medium pressure gauge 13a is electrically connected to an electric-air converter 21b for operating the spray medium supply valve 9a, and the opening position of the three-way switching valve 16, which is a switching valve between slurry and purge medium, is electrically connected to the spray medium pressure gauge 13a. Adjust. Note that the limit switch 17 is also electrically connected to these electric-air converters for operating the slurry medium supply valve 10 and the spray medium supply valve 9a via contacts 20a and 20b.

In the configuration shown above, the operation of starting the burner will be specifically described.

The three-way switching valve 16 is first placed in an open position with respect to the slurry medium (water in the case of CWM), and the water supply valve 10 is opened. The flow rate of water necessary for cooling the burner gun is set in advance for the pressure regulator 19, and the flow rate of water is adjusted by the regulating valve ■0 to the cent value of the water flow rate, and the pressure gauge 12a is adjusted to the actual value. Measures water pressure and feeds back the results. In addition, since the flow rate of water itself becomes a problem during cooling, the pressure gauge 12a
The controller 19 may also be of a flow rate regulating type.

Next, in order to check whether the burner gun has been cooled to a temperature at which the fuel will not solidify even if slurry fuel is supplied, the actual temperature of the burner gun is measured using the temperature switch 24, and the measured temperature is set to a predetermined value. When the value reaches , the three-way switching valve 16 is switched from the medium supply side to the slurry fuel supply side. By actually measuring the temperature of the burner gun using the temperature switch 24, it is possible to avoid situations where the burner gun is cooled more than necessary or insufficiently cooled. Furthermore, the amount of cooling medium used can be kept to the minimum necessary level. In this case, if the burner chip is made of ceramic, it can effectively cope with the thermal stress caused by the injection of the cooling medium.

In addition, if the temperature and flow rate of the cooling medium are set to predetermined values, and the specific heat etc. of the materials that make up the burner gun to be cooled are known, instead of actually measuring the temperature of the burner gun, The supply time of the cooling medium may be set by the timer 23, and the cooling medium may be supplied within a predetermined period of time. Temperature switch 24 or timer 2
The signal outputted to the three-way valve 16 by 3 is simultaneously transmitted to the pressure regulator 19, and the cooling water pressure setting of the regulator 19 is canceled, and from then on, only slurry fuel is supplied for steady operation. to go into. By switching between the slurry medium and the slurry fuel using the three-way valve in this way, the slurry medium and the slurry fuel are not mixed unnecessarily at the time of switching, and the switching between the slurry medium and the slurry fuel is prevented. This can be done reliably and quickly.

While the slurry medium is cooling the burner and purging the residual fuel, the atomizing medium supply valve 9 and the control valve 9a are also kept open, and the signal from the pressure regulator 19 is adjusted in the same manner as in the case of the slurry medium 4. The atomizing medium 3 is also supplied to the burner gun 1 while the pressure of the atomizing medium is adjusted based on this. As a result, an appropriate pressure is applied to the slurry medium 4, and the slurry medium 4 is well atomized.
It is possible to prevent situations such as dripping into the furnace. Furthermore, there is no local cooling of the heat exchanger tubes in the furnace, and damage due to thermal stress can be prevented. The pressure of the spray medium 3 is set lower than that when slurry fuel is supplied, so as to prevent cooling of the burner gun from being hindered by the temperature of the steam, which is the spray medium, as much as possible. In other words, this pressure setting is for cooling (purge)
It is desirable to set the pressure to the minimum necessary level within a range that does not cause the medium to drip into the furnace. Furthermore, when switching to the slurry fuel supply mode, the control set pressure of the supply valve 9a by the pressure gauge 13a is changed based on the signal of the limit switch 17 of the three-way valve 16, thereby achieving optimal atomization of the slurry fuel. The setting pressure can be selected as follows.

Next, the operating state when the burner is extinguished will be explained.

When the burner is extinguished, the slurry extinguishing signal first sets the opening of the purge water supply valve 1o using the pressure regulator 19, and at the same time, the three-way valve 16 changes from "slurry supply" to "slurry medium (water) supply". Switch. In this state 3
The pipe on the downstream side of the direction valve 16 and the burner gun are filled with slurry fuel. For this reason, a large pressure loss occurs in order to purge the residual fuel, so the pressure setting in the pressure regulator 19 is set high so that the pressure at the pressure gauge 12a becomes high. At this point, what is being sprayed from the burner gun is the remaining slurry fuel itself, so the supply pressure of the atomization medium is also set to a pressure sufficient to atomize the residual slurry fuel. As the purge progresses in this state and the residual slurry fuel in gun 1 disappears, the pressure loss will drop rapidly. Therefore, if the set pressure remains the same, a large amount of purge medium will enter the furnace unlike in conventional equipment. I end up. For this reason, the pressure gauge 12
The set pressure of the regulator 19 is configured to be switched immediately if there is a sudden drop in pressure at point a or a sudden increase in the purge medium flow rate measured by a flow meter (not shown). Specifically, the amount of medium introduced into the furnace is kept to a minimum by controlling the opening degree of the valve 10 to reduce the measured pressure at the pressure gauge 12a. At the same time, the atomizing medium pressure is also reduced to prevent overheating of the purged burner gun.

In the embodiment described above, CWM is used as the fuel to be supplied.
has been described as an example, but it is not limited to this, and it can be effectively used when the constituent medium is a liquid that evaporates and has a large viscosity difference from the slurry.

Effects> As described above, the present invention is configured so that purging and switching between the burner cooling medium and the slurry are performed by a three-way valve, so that the purge of residual slurry fuel in the burner, the cooling of the burner, and the switching of the slurry supply are performed. Switching between various operating states of fuel supply can be performed quickly and reliably.

Further, when purging the residual slurry fuel in the burner and cooling the burner, it is possible to effectively purge and cool the burner using the minimum necessary amount of slurrying medium.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a slurry fuel combustion apparatus showing an embodiment of the present invention, and FIG. 2 is a system diagram of a conventional slurry fuel combustion apparatus. 1... Burner gun 2... Slurry fuel 3... Spraying medium 4... Slurrying medium 5... Piping for slurry fuel 6... Piping for spraying medium 7... Piping for slurrying medium 9a ...Spray medium flow rate control valve

Claims (4)

[Claims] (1) In a device that supplies slurry fuel to a burner gun and atomizes and burns this slurry fuel with a spray medium, the pipe that supplies the slurry fuel is connected to the pipe that supplies the slurry fuel, and the pipe that supplies the slurry fuel is connected to this connection. A switching valve is installed for the downstream side of the connection, a device is installed to measure the pressure or flow rate of the fluid in the pipe, and a device is installed for the burner gun to measure the temperature of the burner gun, and the residual slurry fuel is purged. A slurry fuel combustion device characterized in that a switching operation of a switching valve is performed depending on changes in the pressure or flow rate of fluid in the piping at times, and changes in burner temperature during cooling of the burner gun. (2) A device for measuring the temperature of the burner gun and a device for measuring the pressure or flow rate of the fluid in the pipe are each connected to a timer and/or a pressure regulator by a signal circuit, and the timer and/or pressure regulator further converts the slurry. The slurry fuel combustion apparatus according to claim 1, further comprising a signal circuit connected to a valve for regulating the flow rate of the medium. (3) For the piping that supplies the spray medium to the burner gun, a device for measuring the pressure of the fluid in the pipe is installed downstream of the valve that adjusts the flow rate of the spray medium, and this device and the flow rate of the spray medium The slurry fuel combustion apparatus according to claim 1, wherein the slurry fuel combustion apparatus is connected to a valve for regulating the fuel by a signal circuit. (4) Slurry fuel combustion according to claim (1), characterized in that the slurry fuel is a fuel mixed with coal and water, and water is used as the medium for purging the residual slurry fuel and cooling the burner gun. Device.