JPS5920386A - Coal ash slag disposer - Google Patents

Abstract

PURPOSE:To simply cool and crush molten slag without using water, by connecting an indirect heat exchanger directly beneath a spout-layer gasifier. CONSTITUTION:A coal slag disposer 14 consisting of a fluid bed-type indirect heat exchanger is connected directly beneath a spout-layer gasifier 4. Namely, pulverized coal 9 and a gasifying agent 7 carried by carrying gas 8 are burned by a burner 10 of a spout gasifying kiln 5 and the produced slag is allowed to flow down through a tap hole 11 to the coal slag disposer 14. Then the slag is quenched by a heat exchanger 12 to give a fine particle and formed into a slagged fluid layer 13 with a fluidizing gas 20 supplied from the bottom. The cooled, finely divided slag is withdrawn by a slag discharger 21 and discharged through a rock hopper 23 and a valve 26. On the other hand, the gas produced in the gasifying kiln 5 is discharged through a refiner 3 and a cooler 2 and partially sent as the fluidizing gas 20 to the disposer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spouted bed coal gasifier, and more particularly to a coal ash slag processing apparatus suitable for cooling and extracting molten coal ash slag generated from a spouted bed gasifier.

Coal gasification has attracted attention as a new method for expanding coal use.
In addition, gasification-based combined power generation (a power generation system that combines a gas turbine and a steam turbine) is expected to be effective in terms of thermal efficiency, power generation costs, and environmental measures in the near future.

There are four types of gasifiers: fluidized bed type, moving bed type, and spouted bed type. Among these, the spouted bed type has higher gasification efficiency than the others because the temperature inside the furnace is higher, and furthermore, It is also possible to make it thicker, making it suitable as a gasifier for power generation.

The spouted bed sprays pulverized coal together with a gasifying agent such as oxygen (or air) and steam into a gasifier to generate high-temperature gas containing hydrogen and carbon oxide as main components. At this time, the coal ash is actively brought into a molten state and extracted from the opening at the bottom of the gasifier. This molten ash (slag) contains almost no unburned matter and is 1! ,fL,? f. It becomes glass-like when it is discarded, does not emit harmful substances, and has a smaller volume than Norai ash, making it suitable for disposal.

However, when the jet b1 [layer is at 11 temperature and high pressure], the molten slag is removed from the furnace. Conventionally, a water layer with a water circulation system was installed directly connected to the lower part of the spouted bed, and the slag was cooled and pulverized (pulverized due to the difference in expansion coefficient due to rapid cooling) and extracted.

This system has the following drawbacks.

(1) The temperature of the water droplets that cool the molten TKK slag rises due to sensible heat brought in by the molten slag and radiant heat from the opening at the bottom of the gasifier, and water vapor is generated. This water vapor provides a factor that lowers the temperature of the cassification furnace. In addition, when there is a negative 17 fluctuation, excess water vapor causes scum 11
', the furnace temperature tlj control performance deteriorates.

(2) Conventionally, a water circulation system has been used to reduce the amount of water vapor generated. However, ■The amount of circulation becomes large and a water flow control device is required.■The circulating water is cloudy with coal ash slag, so a slag separation device is required.

A slag drying device and a circulating water purification device are required, which reduces the operability of the gasification plant.

The purpose of the present invention is to easily melt slag without using water.
1) To provide an apparatus for grinding, crushing, etc.

In other words, the molten slag treatment device of the coal gasification device needs to have the following functions.

(1) The molten slag dripping from the spouted bed gasifier is rapidly cooled to make it crumbly.

(2) The molten coal ash slag is extracted in a dry manner, the slag processing device 4 is simplified, and the operability of the entire device is improved.

■ Minimize the effects of gas inflow and heat transfer from the slag treatment equipment to the gasifier, and increase the temperature side of the gasifier.
l l'l: to direct.

The inventors have experimentally discovered that a fluidized bed is effective as a device having the above functions.

Figure 1 shows the molten slag of coal ash in a water layer W and a stream H1ib.
J'#, dripped on F', crushed it Q'j,
Q W Shown as the relationship between 1% average particle diameter and temperature. Cooling of the fluidized bed is the same as water layer cooling and IJ.
? Fluidized bed cooling is possible. This is due to the following reasons. Zunawashi, fluidized bed 1. Within +, gas introduced from below is connected to air (・Jitonatsu-C1,
However, this causes a large amount of confusion in which the media grains -f group are active. Therefore, when the molten slag gets mixed into the -C, flow yJb layer -, the molten slag comes into contact with a group of media particles moving 1 (1υ), and immediately heats up. C is cooled. Therefore, the cooling in the fluidized bed F is sufficiently 1
1” Noh.

on the other hand,? The temperature of 1 C) can be easily adjusted by the following method. That is, the medium 164ζ particles in the fluidized bed are ? If,! In order to make strong contact with the outer wall of the liJ+ layer F, the ura.

Motion 1 (heat in 4F ('', medium (, 1 (transmitted by particles to the outer wall of IC motion 06 F) - C1 flow H[J+
When the wall of B+'71- is used as a heat exchange surface, +7a degrees in the moving bed F can be controlled by an external heat exchanger. That is, by increasing the height of the fluidized bed by -1-, the contact area between the fluidized bed and the heat exchanger can be increased or decreased by -V, and the amount of heat dissipated from the fluidized bed kJ'a
7) The temperature within the IL layer can be controlled.

An embodiment of the present invention will be described below with reference to FIG. The overall structure consists of, from the top, an injection furnace 1) an ItM gasifier 4, and a coal ash slag treatment device 14, both of which are directly connected to each other.

In the spouted bed gasification furnace 4, pulverized coal 9 is supplied into the furnace 5 by a carrier gas (nitrogen) 8 together with a gasifying agent (oxygen and steam) 7 from a pulverized coal burner 10 at a high speed.

The pulverized coal 9 turns into a flame forming a virtual circle in the furnace, is gasified while swirling, and a product gas 1 containing carbon oxide and hydrogen as main components is produced.

In the spouted bed gasifier 4, the coal ash slag melted at high temperature is deposited on the furnace wall by the swirling flow, and the slag tap hole 1
Flows down to 1. The coal ash molten slag dripping from the slag tap hole 11 is removed from the coal ash slag processing equipment 1 located directly below.
4 into the fluidized bed 13.

The flow hJJ layer 13 has medium particles made of rapidly cooled and atomized molten coal ash slag, and is cooled by the heat exchanger 12. The fluidizing gas 20 is a cooler 2, a gas 4:
v [Part of the generated gas 1 purified by the vessel 3 is pressurized by the pressurizer 25 (for use in cars, but in addition to C02
Other suitable materials can also be used. Flow b) Sword 13 has a fluidized bed diameter I) compared to a normal fluidized bed? Ratio of dynamic layer height L1)
/i, is set small enough and the slugging-like fl
wake up l.

The temperature of the v1 sieving bed 13 is the heat '1 placed in contact with the lower part of the fluidized bed.
1 is measured by the pair 17 and adjusted by changing the height of the fluidized bed 130 so as to change the contact area between the heat exchanger 12 and the fluidized bed 13. That is, when the temperature of the fluidized bed 13 rises, by increasing the height of the θIC fluidized bed, the contact area of the heat exchanger increases and the amount of heat absorbed increases, and when the temperature decreases, the height of the fluidized bed is lowered. , contact surface U(
without reducing the amount of heat absorbed.

Since the fluidized bed height Dlj is kept at a constant value when the amount of molten slag produced is equal to the amount extracted by the slag discharger 21, when increasing the height of the fluidized bed, the amount extracted by the slag discharger 21 is decreased. When lowering the height of the fluidized bed, the number of extraction claws of the slag discharger 21 is increased. Thus thermocouple 17
Depending on the measured temperature, the controller 19 increases or decreases the rotation speed of the slag discharger 21 to keep the temperature of the fluidized bed constant.

Since the fluidized bed (3) and the water circulation system (system 12) of the heat exchanger are isolated from each other, the pressure in the ylc!1iI1 layer 13, that is, the pressure in the gasifier 5, is not affected. Water circulation pump 16 and discharge pump with a pressure far lower than the pressure in the furnace
4-unit 15 can be used. 'However, since the circulating water system is a closed system, no equipment for purifying the circulating water is required at all.

The coal ash slag extracted by the slag discharger 21 is stored in the lock hopper 23 and is completely extracted by the valves 22 and 26. Coal ash molten slag 2
4 is extracted in a dry manner, so post-processing can be simplified.

The experimental conditions conducted using this apparatus are shown in Table 1. In the figure, 6 is the produced gas for fluidizing the fluidized bed, and 18 is the fluidized bed dispersion plate.

According to the present invention, there are the following effects: (1) Molten slag can be treated without the water surface coming into contact with the gasifier main body, so steam can be prevented from entering the gasifier. Since only the fluidizing gas is mixed in,
The absolute amount of mixed gas can be reduced, and a gas suitable for the gasifier can be selected. This eliminates one of the factors that lowers the temperature of the gasifier, improving operability. j- do.

(2) Since coal ash slag can be processed without coming into contact with water, it is possible to extract the slag dryly. This results in
The discharge process of the slag after being extracted becomes easy, and the complicated operation of extracting the slag from the gasifier is simplified.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram of the weight average particle diameter of slag with respect to fluidized bed temperature in a fluidized bed slag treatment apparatus, and FIG. 2 is a system diagram of an embodiment of the present invention. 1...Produced gas, 2...Produced gas purification device, 3...
・Produced gas cooling device, 4... spouted bed gasification device, 5.
... Entrained bed gasifier, 6... Fluidized bed fluidization generated gas, 7... Gasifying agent, 8... Carrier gas, 9... Pulverized coal, 10... Pulverized coal burner, 11... Slag tap, 12... Heat exchanger, 13... Fluidized bed, 14...
・Coal ash slag treatment equipment 1st θ IOII) ρ 15θ 2θθ 25
θ Sura 7゛me Uri Y1! Temperature ('c)

Claims (1)

[Scope of Claims] 1. A coal ash slag processing device characterized by having an indirect heat exchanger directly connected to the lower part of a 6-IC layer gasifier. 2. 'l'H'l' A coal ash slag treatment system N characterized in that the generated gas of the spouted bed gasifier is used as the fluidizing gas of the fluidized Iff according to claim 1. . 3.f)ll' The coal ash slag processing apparatus according to claim 1, characterized in that coal ash slag is used as the medium particles of the fluidized bed. 4. A coal ash slag processing apparatus as set forth in claim 1, characterized in that the flow B layer temperature is set below the slag quenching and pulverizing temperature. 5, 4M In the description of claim 4, there is provided a coal ash slag processing device (no.