JPS63311016A - Transportation system for clinker ashes - Google Patents

Abstract

PURPOSE:To transport efficiently bottom clinker ashes by installing a means charging and mixing fly ashes from a fly ash collecting means to the start up part of a silo conveyer and a means for controlling the moisture content of clinker ashes by mixing. CONSTITUTION:Clinker and ashes produced by the combustion in the inside of a furnace 9 fall down on the bottom of the furnace 9 and are transported outside the furnace 9 by a water sealing type clinker conveyer 2. The fixed amounts of fly ashes caught by a collecting means are charged into a silo conveyer 5 through a fly ash chute 4 from a fly ash hopper 10 and fine and coarse particles are uniformly mixed. By proper mixture of dry and fine fly ashes having a particle size of around 200 mesh with the clinker ashes containing high moisture content and large particles with a size of around 10mm, the clinker ashes are controlled into a finely packed condition having a uniform and proper moisture content and satisfactory moisture holding property and are successively deposited on the upper part of a clinker silo 6 through a clinker conveyer 5. As a result, this kind of clinker in the finely packed condition controlled in a uniform and proper moisture content does not generate surface moisture.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a pulverized coal-fired boiler, and particularly to a transportation system suitable for adjusting the moisture content of bottom clinker ash and improving transportation efficiency.

(Prior art) Conventionally, in a pulverized coal-fired boiler, clinker and ash generated by combustion in the furnace fall and accumulate at the bottom of the furnace and are discharged by a water-sealed clinker conveyor. Drainage of clinker ash, including granular ash, relies on gravity, and is discharged to the outside by a water-sealed clinker hopper placed at the bottom of the furnace and a clinker conveyor built inside the clinker hopper. Normally, this clinker conveyor is installed only in areas with a water-sealed structure, so the clinker is transported to the top of the silo by another silo conveyor.

However, recent technological advances have improved the performance of pulverized coal pulverizers, resulting in an increase in the particle size of pulverized coal and, accordingly, finer combustion ash. At the same time, in order to reduce nitrogen oxides, the cross-sectional area of furnaces tends to be larger, which reduces the rate of rise of combustion gas in the furnace. Clinker ash tended to fall. For this reason, the amount of moisture accompanying the ash discharged from the water seal section by the clinker conveyor also tended to increase.

(Problems to be Solved by the Invention) Bottom ash has a moisture content in the range of 50 to 55% at the exit of the clinker conveyor, but clinker ash with a high moisture content has an extremely low transport efficiency. By being stored in a silo, the moisture content is reduced to 41%.
When it reaches ~45% or more, only water is separated and remains at the top of the silo as surface water. This surface water had a problem in that it suddenly fell when it was being discharged from the clinker silo to the truck.

Furthermore, even when the conveyor structure is designed to allow good drainage, there is a problem in that the efficiency of transporting ash is reduced. The present invention aims to solve the above problems and provide a system for efficiently transporting bottom clinker ash.

(Means for Solving the Problems) The above object is achieved by mixing dry fly ash into bottom ash having a high moisture content and adjusting the moisture content to an appropriate level.

(Function) By mixing dry, fine fly ash into clinker that has a high moisture content and a relatively large particle size, the clinker ash becomes tightly packed and can maintain a uniform and appropriate moisture content.

(Example) An example of the present invention will be described with reference to the drawings. In Fig. 1, 1 is a clinker hopper, 2 is a clinker conveyor, 3 is a rotary valve, 4 is a fly ash chute, 5 is a silo conveyor, 6 is a clinker silo, 7 is a hydraulic gate,
8 is a pulverized coal burner, 9 is a furnace, 10 is a fly ash hopper, and 11 is a chimney. Clinker and ash generated by combustion in the furnace 9 fall and accumulate at the bottom of the furnace 9, and are transported to the outside of the furnace 9 by a water-sealed clinker conveyor 2, where they are collected by a collecting means such as a dust collector (not shown). A predetermined amount of fly ash is fed from a fly ash hopper 10 through a fly ash chute 4 to a silo conveyor 5, where fine particles and coarse particles are uniformly mixed. As mentioned above, clinker ash, which has a high moisture content and includes large particles with a particle size of <10 mm, is mixed with a suitable amount of dried fine fly ash of around 200 mesh to create Tallinn ash, which has a uniform and appropriate moisture content. It is adjusted to a finely packed state with good water retention, and is sequentially deposited on the upper part of the clinker silo 6 via the clinker conveyor 5. Therefore, the clinker in a state of close packing, which is uniform and has an appropriate moisture content, does not generate surface water. The above-mentioned collection means and means for mixing fly ash and clinker are not limited to the illustrated embodiment, but the mixing ratio of fly ash and clinker is such that the above-mentioned finely packed state with good water retention is maintained in the clinker silo. is optimally adjusted and controlled by the running speed of the clinker conveyor, the combustion conditions in the furnace 9, the type of coal, etc.

(Effects of the Invention) By carrying out the present invention, the transport efficiency is improved without requiring a water draining device for the clinker conveyor, and the moisture content of clinker ash is adjusted to a value of around 41%, producing surface water in the clinker silo. is gone.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram showing an embodiment of a clinker ash transport system according to the present invention. 1... Clinker hopper 2... Clinker conveyor 3
... Rotary valve 4 ... Fly ash chute 5 ... Silo conveyor 6 ... Clinker silo 7
... Hydraulic gate 8 ... Pulverized coal burner 9 ... Furnace 10 ... Fly ash hopper 11 ...
··chimney

Claims (1)

[Claims] 1. The pulverized coal-fired boiler has a clinker hopper with a water-sealed structure installed at the bottom of the furnace, a clinker conveyor constructed within the clinker hopper, and a silo conveyor installed from the terminal end of the clinker conveyor to the clinker silo. The clinker ash transport system is characterized by comprising means for introducing and mixing fly ash from the fly ash collecting means into the starting part of the silo conveyor, and means for adjusting the moisture content of the clinker ash by the mixing. system.