JPH0227330Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention is a combustion device that controls the air supply amount and fuel supply amount by a mechanical mechanism, and is applicable to both load increase and load decrease. This invention relates to a combustion device that prevents the generation of black smoke by attaching a mechanical delay device to a link rod connected to a common shaft.

<Prior art and its problems> There is a strong demand for the use of combustion devices that meet the objectives of energy conservation and pollution prevention, not only in large combustion devices but also in small combustion devices. However, these two measures, energy saving and pollution prevention, are often incompatible and contradict each other in the fields of NOx reduction measures, SOx reduction measures, noise control measures, etc.

However, it is difficult to achieve both environmental measures and energy conservation measures at the same time.
There is an _O2 driving method. When burning fuel in a normal boiler, if it is combusted with the theoretical amount of air, the amount of oxygen (O ₂ ) in the boiler exhaust gas will be almost negligible, resulting in ideal operation. The method of operation in which the amount of O ₂ in the exhaust gas is reduced to an extremely low value, for example, 1% or less in large boilers, etc., by burning with a so-called small amount of air, which is close to the theoretical air amount, is hereinafter referred to as low O ₂ operation. I'll decide.

As a result of performing such low O ₂ operation on two types of fuels e and d, the relationship between the amount of SO ₃ (ppm) in the exhaust gas and the O ₂ content in the exhaust gas is as shown in Figure 1. Ta. In other words, the lower the O ₂ content in the exhaust gas, the less SO ₃ is generated. Also sulfur (S)
In the operation carried out on two types of fuel with a content of 3.0% and 1.5%, the dew point of the exhaust gas and the O ₂
The relationship between the two is as shown in Figure 2. low
O ₂ operation reduces the rate of conversion from SO ₂ to SO ₃ , lowering the dew point temperature and increasing the effect of preventing low-temperature corrosion of the equipment.

In addition, in low O ₂ operation, the air supply amount is reduced, so the exhaust gas temperature can be lowered, and the boiler efficiency can be increased.

In addition, low O ₂ operation reduces the O ₂ concentration in the combustion section, which reduces NOx generation and has a significant effect on pollution prevention.

In this way, low O ₂ operation can produce various favorable effects, such as improving the structure of combustion equipment,
Various measures have been adopted to enable low O ₂ operation, such as the use of high quality fuel.

Therefore, in large-capacity, large-scale boilers, various factors are detected and operated in accordance with these factors in order to achieve suitable low O ₂ operation at the expense of operating equipment.

However, there are very few examples of such low O ₂ operation being implemented in small capacity boilers or package boilers. The main reasons for this are: (1) This type of boiler has particularly large load fluctuations.

(2) There is a problem of black smoke generation associated with this.

There are two.

In other words, there is a problem in the ability to suitably supply combustion air in response to load fluctuations.

FIG. 3 is an explanatory diagram showing a mechanical control system of a combustion device in a package boiler. Boiler 1
The steam pressure of the drum 1a is transmitted to a pressure regulator 2, and the pressure signal is transmitted to a control motor 4 via a balancing relay 3 as an electric signal. The rotation of the shaft of the control motor 4 is transmitted to the common shaft 5 by the link device, and the rotation controls the damper 6a in the combustion air duct 6, and at the same time controls the oil amount control valve 7 provided in the fuel supply pipe 8. Control. That is, two elements, the supply of fuel and the amount of air required for its combustion, are controlled by opening and closing operations that are approximately proportional.

However, in this case, while the boiler furnace internal pressure decreases under low load, the wind pressure at the outlet of the blower increases due to the rotation of the damper in the closing direction, and the differential pressure across the damper 6a increases. Conversely, when the load is high, the differential pressure across the damper 6a becomes small. Because these pressure differences occur, controlling the amount of air by controlling only the opening area of the damper becomes inaccurate, making it difficult to perform combustion control appropriately. Therefore, as shown in FIG. 4, a damper 10 is provided in the inlet duct of the blower 9 to control the control motor 11.
and a damper 6a controlled by the control motor 4 to control the amount of air supplied, and the combustion air is sent into the furnace via the air heater 12 to generate a low O ₂
It cites the effects on driving.

However, this increases the number of systems including the control motor 11, and there is a need to propose a simpler device. In addition, in general, in large boilers, control of the two elements of fuel supply amount and combustion air amount to prevent the generation of black smoke is performed using electric Only standard measures are adopted, such as fuel valves,
The air valves are operated using compressed air through a converter (electrically operated), and the needle valves and check valves may also be configured with electrical circuits. Its operation is as follows: (1) When the load increases, the fuel supply amount is increased with a delay.

(2) When the load decreases, reduce the air supply amount with a delay.

As a result, a so-called air rich condition is maintained in which the amount of supplied air is always greater than the theoretical amount of air, thereby preventing the generation of black smoke during load fluctuations. However, the use of such electrical means requires a large number of electrical equipment and increases costs, which is particularly unsuitable for small-sized boilers.

<Purpose of the invention> This invention provides a mechanical delay device that is formed only from mechanical components that do not require any electrical parts and can be connected to a link rod with a simple structure, and is suitable for use in large boilers with frequent load fluctuations. It also enables low O ₂ operation with simple means, especially in small boilers and even in existing boilers.
The purpose of this study is to propose a device that prevents the generation of black smoke during load fluctuations.

<Summary of the means> A pipe line is provided to connect one end face of the cylinder and the other end face where the piston rod extends, and a check valve and a flow rate control valve are provided in the pipe line, the check valve and the flow rate control valve having mutually different check directions, The cylinder houses two piston balance springs, and the cylinder and conduit form a mechanical delay device filled with hydraulic fluid, leaving a volume of gas approximately equal to the volume of the piston rod entering the cylinder. A mechanical delay device is connected to the fuel valve and combustion air damper link rods.

<Example 1> An example of this invention will be described with reference to FIGS. 5 to 8. First, an embodiment in which a mechanical delay device 13 according to the present invention is provided in the combustion control system shown in FIGS. 3 and 4 is shown in FIGS. 5 and 6. FIG. 7 shows an embodiment in which the combustion control system has almost the same configuration as the combustion control system shown in FIG. In these figures, the same reference numerals as in FIGS. 3 and 4 represent the same members, and redundant explanation will be omitted.

As shown in FIGS. 5 to 7, between the common shaft 5, which is the control mechanism drive shaft, and the air control damper 6a,
Similarly, a rod 14 with a mechanical delay device is provided between the common shaft 5 and the oil amount control valve 7, which is a fuel adjustment valve. Of these figures, the seventh
This will be explained using the figure as a representative example. In the illustrated example, the link rod 5a that operates the oil amount control valve 7 in conjunction with the common shaft 5 is replaced with a mechanical delay rod 14, and the link rod 5b that operates the damper 6a in conjunction with the common shaft 5 is replaced with a mechanical one. It has been replaced by a rod 14 with a time delay device. The mechanical delay device 13 provided on the oil flow control valve 7 side delays the opening of the oil flow control valve 7 when the load increases, and is set in the manner described later so that the delay in opening the oil flow control valve 7 is reduced when the load decreases. I'll keep it. The mechanical delay device 13 provided on the damper 6a side is set in the manner described below so that there is little delay in opening the damper 6a when the load increases, and a necessary delay in closing the damper 6a when the load decreases. I'll keep it.

Next, the structure of the rod 14 with a mechanical delay device will be explained with reference to FIG. The rod 14 with a mechanical delay device connects a cylinder-equipped rod 14a and a piston rod 14b, which resides and operates in this cylinder 15, to the oil amount control valve 7 and the common shaft 5, respectively, as constituent members of the mechanical delay device 13.

Inside the cylinder 15 is a pair of balance springs 17a, 1.
7b is placed between the pistons, and the degree of compression of the springs is adjusted by the spring presser cover 16. The cylinder 15 is charged with a normal liquid oil as a working fluid, and the oil is selected to have an appropriate viscosity. When charging oil, the volume of gas remaining in the cylinder and pipe line is approximately equal to the volume of the piston rod entering the cylinder. Two nozzles 18a and 18b are provided on the bottom wall of the cylinder 15 and the spring presser cover 16, respectively, and a conduit 19a connects one nozzle 18a and one nozzle 18b, and a conduit 19a connects one nozzle 18a and another A conduit 20a is provided to connect to the nozzle 18b. One of the fluid pipelines 19a is provided with a check valve, that is, a check valve 19b and an adjustment needle valve 19c, which provide no resistance when oil flows from the bottom wall of the cylinder and prevent it from returning to the bottom surface. It is assumed to be device 19. In this case, the opening degree of the adjustment needle valve is set large for the damper, and set small for controlling the amount of fuel. The other conduit 20a is provided with a check valve, that is, a check valve 20b, and an adjustment needle valve 20c, which have no resistance when oil flows from the spring presser cover 16 side and are prevented from returning to the spring presser cover 16 side. A set of fluid conduit devices 20 is provided. In this case, the opening degree of the adjusting needle valve 20c is kept small for the damper and large for controlling the amount of fuel.

Next, the operation of this device will be explained. When the load increases, a lever driven by the control motor 4, a common shaft 5, a rod 14 with a mechanical delay device,
14, the piston rod 14b moves in the direction of arrow A in FIG. At this time, since the opening degree of the needle valve 20b attached to the oil amount control valve 7 side is set to a large degree, the piston moves relatively freely inside the cylinder 15 because the oil flows relatively freely through the pipe 20a. freely moving, so that the cylinder rod 14a moves at a slower speed than the speed of movement of the piston rod 14b. Therefore, the oil amount control valve 7
The opening operation is delayed. On the other hand, since the opening degree of the needle valve 20c attached to the damper 6a side is set small, when the piston rod 14b moves in the direction of arrow A, even if oil tries to flow through the pipe line 20a, the needle valve 20c The flow is blocked to some extent by the cylinder rod 14a, so that the cylinder rod 14a moves at approximately the same speed as the piston rod 14b.

Therefore, there is no delay in the opening operation of the damper 6a.

Next, when the load is reduced, the piston rod 14b moves in the direction of arrow B, contrary to the above. At this time, the needle valve 19c installed on the oil amount control valve 7 side
Since the opening degree of is set small, the oil flows through the pipe 19a.
Even if the piston rod 14a tries to flow through the piston rod 1, the flow is blocked to some extent by the needle valve 19c, so that the cylindrical rod 14a is almost connected to the piston rod 1.
Moves at the same speed as 4b. Therefore, the closing operation of the oil amount control valve 7 is not delayed. On the other hand, a needle valve 19c provided on the damper 6a side
Since the opening degree is set to be large, when the piston rod 14b moves in the direction of arrow B, the oil flows into the pipe 19.
a relatively free flow allows the piston rod 14b to move relatively freely relative to the cylinder 15, so that the cylinder rod 14a
moves at a speed slower than that of the piston rod 14b. Therefore, the closing operation of the damper 6a is delayed.

To summarize the above, (1) When the load increases, the damper opens relatively quickly, earlier than the opening operation of the oil flow control valve, the air volume increases relatively rapidly, and the fuel supply volume lags behind this. and increase.

(2) When the load decreases, the oil flow control valve rapidly operates in the closing direction, but the damper closes with a delay, and the air supply decreases with a delay.

In this operation, the balance spring 17a,
The oil subjected to the force due to the difference in the degree of compression of the valve 17b flows little by little through the adjusting needle valve 20c and is balanced at the set positions of the damper and the oil amount control valve. The delay in operation time between the oil amount control valve 7 and the damper 6a due to load fluctuations can be made by adjusting the adjustment needle valves 19c and 20c on the oil amount control valve 7 side and the damper 6a side.

Such a mechanical delay device looks similar to a shock absorber at first glance, but there is no known device that connects the two conduits 19a and 20a and operates in both forward and backward motions.

In addition, by taking advantage of this characteristic, we have been able to provide an extremely effective device that prevents the generation of black smoke by connecting the fuel valve operation and the damper operation with different delayed operations.

In addition, all hydraulic shock absorbers are unidirectional shock absorbers.
In addition, an air tank is provided at one end of the cylindrical body (for example, Utility Model Publication No. 50-32695), which has a simple structure, and has a structure that allows for delay and adjustment of the second action. do not have.

<Effects> By implementing this invention, by simply installing a rod with a mechanical delay device in place of the conventional link rod, time delay operation can be made easier in place of the conventional complicated electrical device. The activation delays of the fuel valve and damper can be made contradictory,
Regardless of whether the load is increased or decreased, it is possible to prevent the generation of black smoke due to load fluctuations, and there is no need for special monitoring and adjustment of the control device, and low O ₂ operation is performed to prevent pollution and save energy. In addition, it has various effects such as being easy to install in an existing boiler.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between O ₂ and SO ₃ in exhaust gas, Figure 2 is a diagram showing the relationship between O ₂ in exhaust gas and dew point temperature for the sulfur (S) component contained in fuel, and Figure 3 is a diagram showing the relationship between O 2 in exhaust gas and dew point temperature. Figure 4 is a diagram showing the fuel and air control system in a small boiler, Figure 4 is a diagram of the control system including blower inlet damper control, and Figures 5 and 6 are Figure 3.
Figure 7 shows a control system in which the mechanical delay device 13 according to the present invention is installed in the control system shown in Figure 4, and Fig. 7 shows a control system in which the mechanical delay device 13 according to the invention according to the present invention is installed in the control system shown in Figure 5. FIG. 8 is a longitudinal sectional view of an embodiment of the mechanical delay device according to the present invention. 1... Boiler, 5a, 5b... Link rod,
6a... Damper, 7... Oil amount control valve, 13... Mechanical delay device, 14... Rod with mechanical delay device, 14a... Rod with cylinder, 14b...
Piston rod, 15... Cylinder, 16... Spring presser cover, 17a, 17b... Balance spring, 18
a, 18b... Nozzle, 19, 20... Fluid pipe device, 19a, 20a... Pipe line, 19b, 20b
... Check valve, 19c, 20c ... Adjustment needle valve.

Claims (1)

[Scope of utility model registration request] In a system that delays the response of either the air supply amount or the fuel supply amount to the combustion device during the transition period of the load fluctuation of the combustion device, the fuel/air ratio is made appropriate and black smoke generation is prevented. A damper that controls the fuel supply amount and a fuel adjustment valve that controls the fuel supply amount are each linked and connected to the control mechanism drive shaft, and each link rod is provided with a mechanical delay device, and this mechanical delay device is connected to a rod with a cylinder, The piston rod of the piston sliding in this cylinder, a set of piston balancing springs, a spring presser cover, the bottom wall side of the cylinder, and the spring presser cover side are connected to form a passage for the fluid in the cylinder. It consists of two sets of fluid piping devices, each of which has a flow control valve in its fluid passage and a check direction for fluid flow that is different from the checking direction in the other fluid piping device. A check valve is interposed therebetween, and the cylinder and the fluid pipe are filled with a hydraulic fluid so that a volume of gas approximately equal to the volume of the piston rod entering the cylinder remains. A combustion device that prevents the generation of black smoke.