JPH0668366B2 - High efficiency coal burner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a spouted bed powder solid fuel gasifier, in particular, coal is used as a powder solid fuel and contains 50% or more of unburned carbon. The present invention relates to a burner that can continuously supply a chain at the same time without blockage and can efficiently gasify.

[Conventional technology]

Coal has the largest reserves among fossil fuel resources and is attracting attention as an alternative energy source for oil.

Coal is solid and inconvenient to handle, and contains ash, sulfur, nitrogen and the like, and in order to be effectively used, it is desired to convert it into a clean energy source by liquefaction, gasification and the like before use. At present, coal gasification is drawing attention as an effective method for converting coal into a clean fuel. Among them, a coal gasification combined cycle power generation system that uses clean gas from coal for power generation is drawing attention. Coal gasification power generation One of the important technologies that supports the combined power generation system is coal gasification technology. As a gasification furnace for power generation, high gasification efficiency, operability and reliability that can meet power demand, application to a wide range of coal types Sex is required. In order to satisfy these requirements, a fusulized bed gasification furnace in which pulverized coal is reacted in an air stream is promising.

The blown-bed gasifier is the Koppers-Totzek system, CE in the United States.
Methods, Texaco method, etc. are under development aiming at large capacity and high performance. In Japan, several companies started development in 1945-35, and developed their own gasifier for the purpose of producing ammonia synthesis gas.

As a means for improving the efficiency of the gasification furnaces used for these, most of them mainly aim to retain the solid fuel in the furnace as much as possible to promote the gasification reaction. However, in any gasification furnace, there is a chain containing unburned carbon that scatters from the gasification furnace without reacting. Therefore, as a means for suppressing the amount of scattering char, the furnace structure, the installation position of the burner, the blowing speed of the burner, etc. are examined, but there is a limit to the suppression of scattering.

Therefore, any reactor has a circulating system to the gasification furnace of the scattered chaff. The supply method includes 1) a case where it is always supplied with coal, and 2) a case where it is supplied intermittently at a certain fixed time.

To maintain efficiency above a certain level at all times, 1)
It will be a method of always supplying.

Therefore, a structure and means of a burner that can efficiently supply gas without causing blockage by continuously supplying it are important.

As a means for supplying the char, 1) a method of supplying coal and the char from separate burners. 2) There is a method of supplying gas from the same burner into the gasification furnace. In the method of 1), since the burner for supplying the coal is installed at a position different from the burner for supplying the coal installed in the furnace, it is possible to adversely affect the flow state of the particles in the furnace and increase the amount of the scattered shatter. There is a nature. In the method of 2), since the chain is supplied together with the coal from the determined position, the flow of particles in the furnace is not so affected. Moreover, a new gasifying agent line is not required and the control is easy.

Therefore, comparing the methods 1) and 2), it can be said that the method 2) is advantageous. Therefore, we decided to consider the present invention by the method of 2).

Conventionally, a burner structure for simultaneously supplying pulverized coal and chewer is basically represented by two methods. 1) A method in which a concentric circular cylinder is made into a double tube and a channel and a pulverized coal are supplied into the central flow passage and the outer tube (JP-A-59-134405). 2) A method in which the powder supply pipes are inserted in parallel in the burner (JP-A-56)
-124812) etc.

[Problems to be solved by the invention]

Gasification of solid fuels generally requires reducing the amount of gas required to transport powdered solid fuels as much as possible. The reason for this is that an inert gas (nitrogen, carbon monoxide, etc.) is generally used for powder fuel transportation, and if the amount is large, it suppresses the rise in the temperature inside the furnace, which adversely affects the reaction surface and the slag flow. . Therefore, it is necessary to reduce the amount of carrier gas, which inevitably increases the density of the powder fuel in the mixed laminar flow. Therefore, when the above (1) is used, it is considered that the bent portion of the coal supply pipe is worn. In addition, if a chain supply pipe is installed in the coal supply system, resistance increases, and it is conceivable that blockage will occur in the burner and in the coal supply line. In addition, the tip of the method 1) is an external mixing type, and there is a possibility that the mixed state of coal and cheer and the contact between the powdered fuel and the gasifying agent deteriorate when the conditions change.

In the method 2), the contact with the gasifying agent at the outlet of the burner tip is poor and there is a possibility that the amount of the char containing a large amount of unburned carbon will increase.

An object of the present invention is to provide a burner structure capable of continuously supplying powdered solid fuel and a chain from a single burner without blockage, and at the same time improving the contact between the powdered fuel and the gasifying agent to improve efficiency. To provide.

[Means for solving problems]

The above-mentioned purpose is to make the inside of the powder supply pipe installed in the burner into a double pipe, to separately circulate the pulverized coal in the central flow passage and the inside of its outer cylinder pipe, and to mix the coal and the chaper inside the tip of the powder supply pipe. By providing a gasification mixing chamber at the burner outlet tip in order to make good contact with the particle mixing chamber and the gasifying agent (oxygen, air), there is no blockage in the powder supply pipe, and continuous supply is possible, and It is designed to improve efficiency.

[Action]

That is, the coal and the chaff to be fed into the burner are made into double pipes from the front of the burner and fed from different inlets,
Since the pulverized coal is circulated in the outer tube of the pulverized coal in the central flow passage, there is no resistance in the central flow passage, so that the pulverized coal is not clogged. In addition, since the density of char is smaller than that of pulverized coal and the amount of gas used for transportation is small, wear does not occur. In addition, so-called two-stage mixing, in which a room (gasification mixing chamber) for contacting with a gasifying agent (oxygen or air) is installed after mixing coal and char inside the tip of the powder supply pipe in the burner (powder mixing chamber) By providing the chamber, the contact is improved and the performance is improved.

〔Example〕

In the embodiment, the present invention is applied to the case where the powdered solid fuel is supplied into the high pressure gasification furnace.

The present invention will be described with reference to FIGS. 1 and 2.

As a whole, an outer cylinder pipe (or a cooling pipe) 9, a gasifying agent supply system 2,
It comprises a powder supply pipe 5 and a pulverized coal supply pipe 13. The entire burner has a quadruple pipe structure, and the inside of the burner is cooled by the cooling water 3 passing through the cooling water distribution line 10.

The pulverized coal supply pipe central flow path 4 is embedded in the powder supply pipe 5. In the annular pipe 12 between the powder supply pipe 5 and the pulverized coal supply pipe 13, the chain 1 containing a large amount of end-burning carbon scattered and recovered from the gasification furnace is pressure-fed and flows out from the outlet hole 19. The pulverized coal supply pipe 13 and the powder supply pipe 5 are integrated, and a particle mixing chamber 15 for mixing the pulverized coal 17 and the chain 1 is provided inside the tip of the powder supply pipe to improve mutual mixing, and then the outer pipe 9 By providing a room in which the gasifying agent (oxygen or air) ejected from the gasifying agent outlet hole 8 and the coal + char are in good contact with each other inside the tip of the gas, that is, the gasification mixing chamber 16, the particles and the gasifying agent are provided. Is favorably promoted and then ejected from the ejection port 11.

The high-efficiency burner had a quadruple tube structure, and the cooling water was circulated in the outer tube. The material of this burner is stainless steel (SUS30
4) was used.

The dimensions of each part are the outer diameter of the outer cylinder of the burner φ48, length 60
0 mm, the outer diameter of the gasifying agent protection tube 7 is φ32. The powder supply pipe 5 used had an inner diameter of 12 and an outer diameter of the pulverized coal supply pipe 13 of 6 and an inner diameter of 4. The size of the particle mixing chamber 15 inside the tip of the powder supply pipe 5 is an inner diameter φ12, and the pulverized coal supply pipe 13 is
12 mm from the tip of the powder supply tube to the tip of the powder supply tube, the size of the gasification mixing chamber 16 is 20 mm inside diameter, 24 mm from the tip of the powder supply tube 5 to the tip of the outer tube, and the diameter of the gasifying agent ejection hole φ0.5 mm

The pulverized coal transportation condition is a carrier gas amount of 8 kg / h. The carrier transport condition is a carrier gas amount of 2 kg / h. The supply rate of the char was 2-3 kg / h, and the supply rate of the pulverized coal was 35 kg / h.

One burner of the present invention was installed in the reaction part of the gasification furnace (inner diameter 300 mm, height 750 mm).

Oxygen is used as the gasifying agent, and the ratio of the oxygen supply amount to the pulverized coal supply amount (hereinafter referred to as O ₂ / coal) is adjusted to 0.6 to 0.8.
4 to 32 kg / h was supplied. The test pressure was 4 kg / cm ² G. The coal used is Pacific coal.

The test method is to supply a constant amount of pulverized coal and a
The test was conducted by changing the oxygen amount from 24 to 32 kg / h so that the O ₂ / coal was from 0.6 to 0.8.

As a result, there was no blockage at the pulverized coal supply pipe outlet or the like due to pressure fluctuations in the burner, and good supply was possible with no particular problems.

The experimental results are shown in FIG. Oxygen supply on the horizontal axis / pulverized coal +
The chart (O ₂ / coal + chair) shows the efficiency on the vertical axis. As shown in this figure, the burner of the present invention is
It was found that both the cold gas efficiency and the carbon gasification rate are increased by about 2 to 3%, which is effective.

〔The invention's effect〕

According to the present invention, it is possible to continuously supply the mixed particles of the pulverized coal and the char without clogging, and by installing the two-stage mixing chamber in the burner, the efficiency is improved as compared with the conventional burner. Has the effect of

[Brief description of drawings]

FIG. 1, a cross-sectional view of a high-efficiency powder mixing burner of the present invention, FIG. 2, a front view of the burner of the present invention and FIG. 3 show the relationship between combustion efficiency and (oxygen supply amount / coal + chair) ratio. It is a diagram showing. 1 ... chair, 2 ... gasification agent (oxygen or air), 3 ...
… Cooling water, 4 …… Pulverized coal central flow path, 5 …… Powder supply pipe,
6 ... Gas agent supply line, 7 ... Gas agent protective tube, 8
...... Gasifying agent ejection holes, 9 ...... Outer cylinder pipe (or cooling pipe), 1
0 ... Cooling water supply line, 11 ... Spout, 12 ... Chir distribution line, 13 ... Pulverized coal supply pipe, 14 ... Pulverized coal distribution line, 15 ... Particle mixing chamber, 16 ... Gasification mixing Chamber, 17 ... Pulverized coal, 18 ... Pulverized coal ejection hole, 19 ...
... Cha spout hole.

Claims (1)

[Claims] 1. A coal burner in which several circular pipes are coaxially overlapped and a flow path for pulverized coal and its carrier gas, a flow path for char and its carrier gas, and a flow path for a gasifying agent are individually provided. In the above, four circular tubes are stacked to form a quadruple tube structure, pulverized coal and its carrier gas are supplied to the innermost central channel of the quadruple tube, and char and its carrier gas are supplied to its outer channel. Of the pulverized coal and its carrier gas, and the char and its carrier gas. A particle mixing chamber in which the flow path merges, and a gasification mixing chamber that joins the pulverized coal mixed in the particle mixing chamber with the gasifying agent in front of the particle mixing chamber are provided. Efficiency coal burner.