JPH044488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a fluidized bed steam heating furnace that can be used in a fluidized bed steam heating furnace, a fluidized bed heating fuel reforming furnace, a fluidized bed fuel heating furnace, a fluidized bed air heating furnace, etc. Regarding a layer heating furnace.

Conventional technology The fluidized bed heating method has recently been attracting attention as a heating furnace that achieves a uniform heat load distribution and combustion gas temperature distribution, but since the fluidized bed completes combustion within the bed,
A bed temperature of 800°C or higher is required, and a heat recovery section is required downstream of the fluidized bed to recover the heat of the combustion exhaust gas temperature.

Conventionally, it is known that a packed bed is provided above the fluidized bed as this heat recovery section, and the heating of the high temperature part is performed by the fluidized bed, and the heating of the low temperature part is performed by the packed bed. Alumina-based ceramics or the like is used as the filler.

Problems to be Solved by the Invention However, in the case where such a packed bed is provided above the fluidized bed, the pressure loss on the combustion gas side is large in the packed bed, and the particles scattered from the fluidized bed are absorbed into the packed bed. There is a problem that it is easy to get blocked inside.

Therefore, the present invention has been made in order to minimize the power loss of the system by reducing the pressure loss in the combustion exhaust gas heat recovery section in a fluidized bed heating furnace, and to prevent blockage due to particles scattered from the fluidized bed. be.

Means for Solving the Problems The present invention provides a combustion exhaust gas heat recovery unit installed above the fluidized bed, in which an uneven portion is formed on the outer surface of a portion of a heat transfer tube extending in the space above the fluidized bed. A sleeve is placed around the unevenness, thereby solving the conventional problems.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a case where the heat exchanger tubes are penetrating vertical tubes, and the heat exchanger tubes 3 are vertically buried in a fluidized bed 2 held by a furnace wall 1 and penetrated vertically.

The combustion exhaust gas 4 generated within the fluidized bed exits the bed, passes through a heat recovery section 5 provided in the space above the fluidized bed, and exits from the furnace through an exhaust port 6.

On the other hand, the vertical heat exchanger tube 3 is composed of a single tube, and the heat transfer medium 8 flowing into the furnace from the inlet 7 is transferred to the heat exchanger tube 3.
As it passes through the tube, it is heated by the combustion exhaust gas 4 outside the tube, that is, inside the fluidized bed 2 and outside the layer, and exits from the furnace through the outlet 9.

According to this embodiment, the fins 10 are provided by forming irregularities on the outer surface of the heat transfer tube 3 in the space above the fluidized bed 2, and thereby the fin-type combustion exhaust gas heat recovery section 5 is formed. It is configured. Therefore, the thermal energy of the combustion exhaust gas 4 from the fluidized bed 2 is transferred to the heat transfer medium 8 by these fins 10 .

Further, a sleeve 11 is disposed around these fins 10 to narrow the flow path of the combustion exhaust gas 4, thereby increasing the gas flow velocity and improving heat transfer characteristics. These sleeves 11 and fins 1
The range between 0 and 0 is appropriately determined from heat transfer characteristics, pressure loss, and prevention of particle clogging.

Note that the means for forming the uneven portion on the outer surface of the heat exchanger tube 3 is not limited to processing the outer surface of the heat exchanger tube itself into unevenness as shown in the figure, but also forming the uneven portion by winding a coil around the outer periphery of the heat exchanger tube. It is also possible to use other appropriate means such as Further, the structure of the heat exchanger tube 3 may be a hanging type double tube in addition to the vertical penetrating tube as shown. Further, as the fuel used in the fluidized bed 2, coal or fuel gas (alumina or the like is used as the fluidizing medium) can be used.

Effects of the Invention As detailed above, according to the present invention, the flue gas heat recovery section in the fluidized bed heating furnace is of the fin type by forming irregularities on the outer surface of the heat transfer tube, thereby minimizing the pressure loss on the flue gas side. The gas passages defined by these fins are not blocked by particles flying from the fluidized bed.

Moreover, the sleeve 11 as shown in the above-mentioned embodiment
Even in the case where the fluidized bed 2 is provided, clogging by particles scattered from the fluidized bed 2 can be prevented by properly maintaining the distance between the sleeve 11 and the fins 10.

[Brief explanation of drawings]

The drawing is a diagram showing an example of a fluidized bed heating furnace according to the present invention. 2...Fluidized bed, 3...Heat transfer tube, 4...Combustion exhaust gas, 5...Heat recovery section, 10...Fin, 11...
sleeve.

Claims (1)

[Claims] 1. A fluidized bed heating furnace in which slight irregularities are formed on the outer surface of a heat transfer tube extending perpendicularly to the space above the fluidized bed, and a sleeve is arranged around the irregularities.