JPH0438968B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a combustor that is mainly installed in a small-capacity boiler and that appropriately mixes and burns fuel such as liquid and combustion air.

(Prior Art) Generally, in a combustor installed in a small capacity boiler, the diameter of the burner orifice cannot be changed. As a result, in this combustor, as the burner load becomes lighter, the required amount of combustion air decreases, resulting in a decrease in the flow velocity of combustion air and deterioration of combustion characteristics. Contamination at the fuel outlet of the combustor has become a problem.

Therefore, in small-capacity boilers equipped with the above-mentioned combustor, when the boiler load becomes light (less than 50%), the combustor must be controlled to repeat combustion and extinguishing, and during extinguishing, the flue There is a problem in that more heat is released and the boiler efficiency is significantly reduced. Furthermore, since the combustor repeats combustion and extinguishing many times, there is also the problem that the mechanical and electrical life of each device is shortened.

Therefore, as a means to solve the above problem, it is possible to use a proportional combustor for the combustor, or to reduce the diameter of the burner orifice of the combustor to increase the flow rate of combustion air even under light loads. There is a way to maintain it.

However, in small-capacity boilers, proportional combustors are expensive, and if the diameter of the burner orifice is made small, the pressure loss of combustion air at the burner outlet during high loads increases, resulting in Excessive power is required for the blower that supplies the air for use, resulting in costs, noise,
There is a problem in terms of power consumption.

(Problems to be Solved by the Invention) The present invention was devised to solve the above-mentioned problems, and its purpose is to obtain good combustion characteristics even under low load of a small capacity boiler. In addition, it is an object of the present invention to provide a combustor that can maintain high boiler efficiency.

(Means for Solving the Problems) The present invention supplies combustion air from the blower 11 as a swirling flow to the burner throttle port 13 located downstream of the combustion injection pipe 9, and The basic structure of the invention is that an automatic variable device 14 is provided to increase or decrease the opening area according to the burner load.

(Function) When a small capacity boiler equipped with the combustor is operated, the combustor automatically increases or decreases the opening area of the burner orifice according to the burner load using an automatic variable device to control the flow rate of combustion air. Maintain appropriate values. As a result, good combustion characteristics can be obtained over a wide load range, and high boiler efficiency can be obtained even when the boiler is under low load.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Figure 1 shows a small once-through boiler (equivalent evaporation amount: 1800 Kg/H) equipped with a combustor 1 according to an embodiment of the present invention.
, the boiler includes a casing 2, an upper refractory 3, a lower refractory 4, a furnace 5,
It consists of a water pipe 6, a combustor 1, etc.

The combustor 1 according to the present invention includes a wind box 7, a burner inlet guide vane 8, a combustion injection pipe 9,
It is comprised of a draft tube 10, a blower 11, an ignition electrode 12, a burner orifice 13, an automatic variable device 14, etc., and the structure other than the automatic variable device 14 is similar to that of conventionally known devices.

The automatic variable device 14 is installed at the burner throttle port 13 located downstream of the fuel injection pipe 9, and automatically increases or decreases the opening area of the burner throttle port 13 in accordance with the burner load.

Specifically, as shown in FIGS. 2 and 3, the automatic variable device 14 is composed of a guide ring 15, a plurality of approximately crescent-shaped vanes 16, a drive mechanism 17, and the like.

That is, the guide ring 15
A plurality of guide grooves 18 having a predetermined inclination angle are bored at equal intervals.

Further, each vane 16 is rotatably supported within the burner orifice 13 and on the upper refractory 3 by appropriate means, and each vane 16 is provided with a guide ring 15.
is inserted into the guide groove 18 of the guide groove 1.
A driving pin 19 that can move along the vertical axis 8 is provided upright.

Furthermore, the drive mechanism 17 includes a motor 20, an output gear 21 attached to the motor 20, and an output gear 21.
It consists of an intermediate gear 22 that meshes with the intermediate gear 22, a link mechanism 23 interposed between the intermediate gear 22 and the guide ring 15, etc., and rotates the guide ring 15 forward and backward by an appropriate amount. This drive mechanism 17 is automatically controlled by an appropriate control device (not shown) to operate appropriately according to the burner load.

The guide groove 18 of the guide ring 15 allows the drive pin 19 of each vane 16 to move along the guide groove 18 when the guide ring 15 is rotated in forward and reverse directions.
Each vane 16 is formed in such a shape that it can be moved inwardly and outwardly of the guide ring 15, respectively.

Therefore, when the guide ring 15 is rotated forward and backward by the drive device 17, the guide groove 18 and the drive pin 19
Each vane 16 moves inward and outward of the guide ring 15 in cooperation with the guide ring 15, thereby increasing or decreasing the opening area of the burner orifice 13.

In the small once-through boiler, the combustion air blown by the blower 11 is swirled by the burner inlet guide vane 8 and mixed with the fuel injected from the fuel outlet of the fuel injection pipe 9. It flows out into the furnace 5 through the burner orifice 13 while forming a flame. At this time, in the combustor 1, the automatic variable device 14 operates according to the burner load to increase or decrease the opening area of the burner throttle port 13. As a result, even when the burner is under low load, the flow velocity and swirling force of the combustion air can be maintained at appropriate values, and good combustion characteristics can be obtained.

In particular, since the automatic variable device 14 is installed at the burner throttle port 13 located downstream of the combustion injection pipe 9, the automatic variable device 14 maintains the flow velocity and swirling force at appropriate values for combustion. Air is from fuel injection pipe 9
This results in reliable and good mixing with the fuel injected from the fuel. As a result, even better combustion characteristics can be obtained.

4 and 5 are graphs comparing the combustion characteristics of a conventional combustor with a non-variable burner orifice diameter and a combustor 1 according to the present invention when used in the small once-through boiler, respectively. The combustion characteristics of the combustor 1 according to the present invention shown by the solid line are significantly improved at low burner loads compared to the combustion characteristics of the conventional combustor shown by the broken line.

As a result, if the combustor 1 according to the present invention is used, continuous combustion is possible up to a boiler load of 25%,
As shown by the solid line in the graph of Figure 6, the boiler efficiency at a boiler load of 25% when the combustor according to the present invention is installed is as follows: For boiler loads of 50% or less, combustion and extinguishing are repeated in the combustor. The boiler efficiency has been improved by approximately 35% compared to when a conventional combustor that uses a control method is installed. Therefore, fuel consumption will be reduced by 10,000 to 42,000 yen per year using A heavy oil.

In the above embodiment, the automatic variable device 14 of the combustor 1 was composed of the guide ring 15, the vane 16, and the drive mechanism 17, but the automatic variable device 14
is not limited to those in the above embodiments,
As long as the opening area of the burner orifice 13 can be automatically increased or decreased depending on the burner load, its configuration, shape, etc. are arbitrary.

Further, in the above embodiment, the combustor 1 is attached to a small once-through boiler, but the combustor 1 may be attached to another type of boiler.

(Effects of the Invention) As described above, the combustor of the present invention is equipped with an automatic variable device in the burner throttle located downstream of the fuel injection pipe that can increase or decrease the opening area according to the burner load. Even when the burner is under low load, the flow velocity of combustion air can be maintained at an appropriate value, and good combustion characteristics can be obtained. However, since the automatic variable device is installed downstream of the fuel injection pipe, the combustion air maintained at an appropriate value by the automatic variable device mixes reliably and well with the fuel injected from the fuel injection pipe. This results in even better combustion characteristics. As a result, high boiler efficiency can be obtained even when the boiler is under low load, and fuel savings and cost reductions can be achieved.

In addition, when the combustor of the present invention is used, continuous combustion is possible even when the boiler is under low load, so compared to the conventional control system that repeatedly burns and extinguishes the combustor when the boiler is under low load. Combustion and extinguishing are significantly reduced, significantly increasing the mechanical and electrical life of each piece of equipment.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view of a small once-through boiler equipped with a combustor according to an embodiment of the present invention, FIGS. 2 and 3 are perspective views of an automatic variable device for the combustor, and FIGS. 4 and 5 Figure 6 is a graph comparing the combustion characteristics of a conventional combustor and a combustor according to the present invention installed in a small once-through boiler, respectively. This is a graph comparing the boiler efficiencies of the two when installed in a boiler. 1 is a combustor, 13 is a burner throttle, and 14 is a variable device.

Claims (1)

[Claims] 1 A burner throttle port 1 located downstream of the fuel injection pipe 9 that uses the combustion air from the blower 11 as a swirling flow.
3, and the burner throttle port 13,
A combustor characterized by being provided with an automatic variable device 14 that adjusts the opening area to increase or decrease depending on the burner load.