JPH04110501A - Pressurized fluidized-bed boiler - Google Patents

Abstract

PURPOSE:To assemble a boiler into a compact shape and prevent tubes of a superheater and a reheater from being burnt at rapid start-up by a method wherein a furnace, in which the evaporator tubes are provided, and a furnace, in which the superheater tubes are furnished, are separately built and housed in a horizontal pressure vessel. CONSTITUTION:A fluidized bed furnace (evaporator furnace) 2 in which evaporator tubes 4 are provided and a fluidized bed furnace (SH/RH furnace) 3 in which superheater tubes 5 and reheater tubes 6 are furnished are separately and independently arranged in a horizontal pressure vessel 1. At start-up, the evaporator furnace 2 is started first, and after a sufficient amount of steam is generated, the steam is supplied to the superheater tubes 5 and the reheater tubes 6. Then, the SH/RH furnace 3 is started. As both evaporator furnace 2 and SH/RH furnace 3 are of water-cooled type, water supply to the water-wall of the SH/RH furnace begins at same time the evaporator furnace 2 is started. To shorten the start-up time period of the SH/RH furnace 3, the furnace 3 alone has been heated up by a start-up burner 7. During pre-heating, the temperature of the fluidized bed is controlled with the temperature of tube metal taken into account.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a pressurized fluidized bed boiler, and in particular to the arrangement of heat exchanger tubes thereof.

(Prior Art) FIG. 2 is a system diagram showing an example of a pressurized fluidized bed boiler combined power generation plant. A pressurized fluidized bed boiler uses coal as fuel and is expected to be highly efficient as a plant. However, at present, we are only at the stage where a 100 MW class demonstration plant is scheduled to begin operation this year. In future large-capacity commercial plants, the heat transfer area of evaporators, superheaters, reheaters, etc. will become extremely large, so these will be housed in a pressurized fluidized bed boiler furnace, and a pressure-resistant container to house this furnace will also be installed. One challenge is how to make it as small as possible. In addition, consideration must be given to preventing burnout of the reheater tube and superheater tube during quick start-up, but conventionally there were no measures against this.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION The present invention aims to provide a measure for making a large-capacity pressurized fluidized bed boiler compact and preventing the tubes of the superheater and reheater from burning out during rapid startup.

(Means for Solving the Problems) In order to solve the conventional problem #J, the present invention provides an evaporator tube and a superheater tube in a fluidized bed to form a bubble-type fluidized bed under pressure. A combustion fluidized bed boiler, characterized in that the furnace in which the evaporator tube is installed and the furnace in which the superheater tube is installed are separate, and the separate furnaces are housed in the same horizontal pressure vessel. a pressurized fluidized bed boiler; and an evaporator tube, a superheater tube and a reheater tube within the fluidized bed;
In a fluidized bed boiler that burns by forming a bubble-type fluidized bed under pressure, a furnace in which the evaporator tube is provided and a furnace in which the superheater tube and the reheater tube are provided are separate, and the furnace is a separate furnace. This paper proposes a pressurized fluidized bed boiler characterized in that both are housed in the same horizontal pressure vessel.

[Effect]

According to the present invention, not only can the pressurized fluidized bed boiler be made compact, but also when the furnace is started up, the heat exchanger tube installed in the other furnace is started. Prevents overheating of superheater tubes and reheater tubes.

[Embodiment] FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention. As shown in this figure, a fluidized bed furnace (evaporator furnace) (2) with an evaporator tube (4), a superheater tube (5) and a reheater tube (6)
A fluidized bed furnace (S) I/R1 (furnace) (3) equipped with a fluidized bed furnace (S) I/R1 (furnace) (3) is arranged independently and separately in a horizontal pressure vessel (]).

At startup, the evaporator furnace (2) is first started, and when enough steam is generated, it is supplied to the superheater tube (5) and the reheater tube (6). From here, start-up of the SR/R11 reactor (3) begins.

Note that both the evaporator furnace (2) and the S)I/R)l furnace (3) have a water-cooled furnace wall, so the SH/R)l furnace (3)
) Water is allowed to flow through the water-cooled walls of the evaporator furnace (2) when the evaporator furnace (2) is started. (For drum boilers, can water; for monotube boilers, from the evaporator furnace water-cooled wall to SH/R) l water-cooled wall, or S) I/R) l water-cooled wall to the evaporator water-cooled wall economizer outlet Run water. ) Also, in order to shorten the startup time of the S)l/RH furnace (3), it is heated up independently by a startup burner (7).

Of course, the temperature of the fluidized bed at this time is controlled from the viewpoint of tube metal temperature.

[Effects of the Invention] One of the important problems in pressurized fluidized bed boilers is how small the pressure vessel can be made. In particular, the inner diameter is proportional to the weight of the container to some extent, so it is necessary to select a small diameter from the viewpoint of cost. In the present invention, since the fluidized bed furnace is divided and placed inside the horizontal pressure vessel, a pressurized fluidized bed boiler can be constructed without increasing the inner diameter and with a simple structure.

Furthermore, by dividing the furnace, it is easier to control the metal temperature of the superheater and reheater, and there is no problem of tube burnout (and startup time can be shortened).

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention. Second
The figure is a system diagram showing an example of a pressurized fluidized bed boiler combined power generation plant. (1)... Horizontal pressure vessel; (2)... Evaporator furnace; (
3)...S) I/RH furnace; (4)...evaporator tube; (
5)... Superheater tube; (6)... Reheater tube; (7).
・・Start burner; Figure 1 high) Air temperature

Claims (1)

[Scope of Claims] 1) A fluidized bed boiler in which an evaporator tube and a superheater tube are provided in a fluidized bed and a bubble-type fluidized bed is formed under pressure and combustion is performed, which includes a furnace provided with the evaporator tube and the superheater tube. 1. A pressurized fluidized bed boiler characterized in that a furnace provided with a vessel is separate, and the separate furnace is housed in the same horizontal pressure vessel. 2) In a fluidized bed boiler in which an evaporator tube, a superheater tube, and a reheater tube are provided in the fluidized bed, and a bubble-type fluidized bed is formed and burned under pressure, a furnace provided with the evaporator tube and the superheater. A pressurized fluidized bed boiler characterized in that a tube and a furnace provided with the reheater tube are separate bodies, and the separate furnaces are housed in the same horizontal pressure vessel.