JPS6210595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spouted fluidized bed type low calorie gasification apparatus for producing fuel gas from coal.

Conventional spout fluidized bed gasifier has a temperature of 700 to 900℃.
It is possible to relatively easily produce a heating fuel gas of 1000 to 1500 kcal/Nm2 at a temperature of 1,000 to 1,500 kcal/ ^Nm2 , and is known as one of the few coal gasifiers that has been put into practical use on an industrial scale. However, this type of gasifier has the drawback that there is a lot of flying sinter, and when coal having a wide particle size distribution is gasified, falling coal is generated from the hopper, resulting in a large amount of unburned loss.

In order to prevent this unburned loss, a two-stage gasification system has been attempted in which two gasifiers are connected vertically and gasified in two stages, as shown in FIG. Steam S and air A are blown into each furnace bottom as gasifying agents. However, with this method, the temperature of the upper stage gasifier 1 decreases and a large amount of tar is generated, making it impossible to achieve the expected reduction in unburned loss. Tar trouble occurs. Further, the upper gasifier 1 and the lower gasifier 2 are connected via a constriction part 3,
The fallen coal is transferred from the upper gasifier 1 to the lower gasifier 2,
Since the fuel gas moves in the opposite direction and the two furnaces are physically connected, there is a drawback that it is difficult to control both furnaces.

An object of the present invention is to provide a coal gasification apparatus using a new gasifier and a chir combustion furnace that eliminates such drawbacks of the conventional two-stage gasifier.

Another object of the present invention is to utilize the coal gasification apparatus of the present invention in conventional heavy oil-fired boilers, heating furnaces, hot blast furnaces, coal kilns, etc., thereby easily and economically converting the fuel into The goal is to enable conversion to coal.

Next, an embodiment of the gasification apparatus of the present invention will be described based on the drawings.

As shown in FIG. 2, the gasifier 10 has an inverted conical shape, with a gasifier blowing chamber 12 at the bottom via a throat 11 and a coal supply hopper 14 at the side via a screw conveyor 13. is connected.

The gasifying agent blowing chamber 12 has a cylindrical shape, and has an inlet for blowing a gasifying agent consisting of water vapor S and air A in a tangential direction on the side surface. The bottom of the gasifying agent blowing chamber 12 is provided with a chear transfer means, that is, a chard storage tank 15.
and communicates with the side surface of the chir combustion furnace 18 via a chute 17 having a damper 16.

The char combustion furnace 18 is a normal fluidized bed furnace, and a wind box 20 having a perforated plate 19 is formed at the bottom of the furnace, and an ash removal pipe 21 fixed to the perforated plate 19 penetrates the wind box 20 and projects downward. An assemblage bin 23 is connected to the side via a screw conveyor 22, and an air preheater 2 serving as a means for heating the gasifying agent is connected to the top.
It is connected to the combustion gas inlet of 4.

The air preheater 24 has two circuits for combustion gas and air separated from each other, the combustion gas outlet is connected to the dust collector 25, the air inlet is connected to the blower 26, and the air outlet is connected to the gasifying agent blowing chamber. Each of them communicates with 12 air inlets.

The blower 27 is connected to the wind box 20 and the ash removal pipe 21.

The top of the gasifier 10 is connected to fuel gas utilization equipment via a single cyclone type dust collector 28 and a multi-cyclone type dust collector 29. The bottom of the dust collector 28 is connected to the top of the dust bin 23 via a dust reservoir 30.

The present invention is configured as described above, but in order to produce fuel gas using this, coal is supplied from the coal supply hopper 14 to the gasifier 10 via the screw conveyor 13. With,
When a gasifying agent consisting of water vapor S and air (or oxygen-enriched air) A is blown into the gasifying agent blowing chamber 12, which has a circular cross section, in the connection direction, the gasifying agent rises while swirling, and the throat 11 is Gasifier 10 via
reach. Since the gasifier 10 has an inverted conical shape, the cross-sectional area increases as it goes upward. Therefore, the cross-sectional gas velocity gradually decreases upward. Coal particles fed into the furnace form a stable fluidized bed above the bottom of the furnace, and are decomposed and gasified by the gasifying agent. The fuel gas produced in this way is passed through the dust collector 2 from the top of the furnace.
The fuel gas is supplied to the fuel gas utilization equipment via 8 and 29.

However, coal particles have a wide particle size distribution, and large particles that do not ride the upward gas flow are found at the throat 1.
1 and is temporarily stored in the chir storage tank 15, and then transferred to the chir combustion furnace 18 via the chute 17.
is supplied to At this time, the damper 16 supplies only chir and prevents the combustion gas from the chir combustion furnace 18 from flowing back into the gasification furnace 10. The chir supplied to the chir combustion furnace 18 is burned on the upper surface of the perforated plate 19. The blower 27 sends combustion air to the wind box 20
as well as to the ash removal pipe 21,
Unburnt fixed carbon in the ash removal pipe 21 is also burned. The combustion gas generated in the chire combustion furnace 18 reaches the air preheater 24 from the top, and after preheating the air A that is tangentially blown into the gasifying agent blowing chamber 12 by the blower 26, it is dedusted by the dust collector 25. The remaining sensible heat is recovered by either being discharged to the outside or sent to a heat recovery device such as a economizer.

Among the scattered sinter collected by the dust collector 28,
Particles having a relatively large size enter the assemblage bin 23 via the chard reservoir 30, and are supplied to the chir combustion furnace 18 by the screw conveyor 22 where they are burned. On the other hand, fine particles are collected by a subsequent dust collector 29 and discarded.

FIG. 3 shows another embodiment of the invention. In this embodiment, a screw conveyor 41 is added as the chear transport means, and the air preheater 24 is used as a gasifying agent heating means.
A mixer 42 is provided instead. That is, from the relative position of the gasifier 10 and the chire combustion furnace 18,
The slope of chute 17 is gentle, and the chute is in chute 1.
If the chute 7 cannot be slid down, the chute 17 may be made vertical as shown in the figure, and the chir may be temporarily stored in a chia hopper 40 provided at the lower end thereof, and then supplied to the chir combustion furnace 18 by a screw conveyor 41. In addition, the entire device is small, and the air preheater 2
4. If it is not economical to install a dust collector 25 and ducts, the combustion gas at a temperature of 850 to 900°C discharged from the char combustion furnace 18 is directly transferred to the gasification furnace 1.
The sensible heat of the combustion gas can also be used for decomposition heat of coal. In this case, if inert combustion gas is blown directly into the gasifier blowing chamber 12 together with air A and steam S, mixing will be poor and the reaction will be uneven, leading to local temperature distribution in the throat 11 of the gasifier 10. Non-uniformity occurs. The illustrated mixer 42 is provided to mix combustion gas, air A, and steam S in advance, and after sufficiently mixing and homogenizing the combustion gas, the mixture is blown tangentially into the gasifying agent blowing chamber 12. The mixture is further mixed and stirred and supplied to the gasification furnace 10 as a high-temperature gasification agent.

FIG. 4 shows, as an example, a system diagram when the fuel gas produced according to the present invention is used as fuel for a boiler. The low calorie gas with a temperature of approximately 900°C generated from the gasifier 50 is sent to the residual heat boiler 51.
After being cooled to about 400°C, the combustion air is heated to about 200°C in the air preheater 52, and the air itself is heated to about 220°C.
It is cooled to 0.degree. C. and supplied to the boiler 53, where it is combusted.
The combustion gas exiting the boiler 53 heats the economizer 54 and then passes through the dust collector 55 and is released into the atmosphere from the chimney 56. The residual heat boiler 51 is designed to have a lower pressure than the boiler 53, and the generated steam is sent to the deaerator 57 and used for deaeration of the feed water supplied to the boiler 53. 58 is a water supply pump.

Conventional fuel gas is stored in a gas holder after being wet-removed, desulfurized, and cooled. but,
This fuel gas is low in calories, so it can be used in residual heat boilers,
The air preheater makes maximum use of the sensible heat possessed by the fuel gas, and also eliminates the need for a gas holder.
By combusting hot gas in a boiler while retaining its sensible heat, the thermal efficiency of fuel gas utilization equipment is maximized.

In addition, in order to convert the fuel of multiple existing heavy oil-fired boilers, heating furnaces, hot blast furnaces, etc. to coal, the 5th
As shown in the figure, if one series of coal gasifiers is associated with a plurality of these units, equipment costs can be further reduced.

As described above, the coal gasifier of the present invention effectively utilizes all of the sensible heat and calorific value of the generated gas, and also gasifies coal in the vicinity of a boiler, heating furnace, hot air stove, etc., and converts it into heat. When gas is used as a conversion fuel, the fuel in the boilers, furnaces, etc. that are designed and operated for liquid fuel can be efficiently converted to coal, and the combustion temperature of low-calorie gas is lower than that of petroleum-based liquid fuel or high-calorie gas. Since the amount of nitrogen oxides generated is low compared to Demonstrate superior effectiveness.

The coal gasification apparatus of the present invention is equipped with a chir combustion furnace and a means for heating the gasifying agent, and effectively utilizes the chiar combustion gas as a heat source for the gasifying agent, that is, the air for gasification, which is supplied to the gasifying furnace. Therefore, the efficiency of the gasifier can be improved extremely economically. Furthermore, in the case of a large furnace, the air for gasification is indirectly heated by exchanging heat with the chir combustion gas using an air heater, and in the case of a small furnace, the gasification agent is heated by the chire combustion in a mixer. As mentioned above, heating the gasifier directly by mixing it with gas can be done by selecting either an air preheater or a mixer as the means for heating the gasifier depending on the scale of the gasifier. Therefore, regardless of the calorific value of the chir combustion gas generated in the chir combustion furnace, the gasification agent can be effectively heated, and the efficiency of the gasification furnace can be improved to the maximum extent possible. .

Furthermore, by blowing the gasifying agent heated by the chir combustion gas into the gasifying agent blowing chamber, fluidized bed formation and gasification are performed in the gasifier. Regardless of the situation, stable and good operation can be achieved. In other words, in a gas furnace in which a perforated plate is installed at the bottom of the gas furnace and the gasifying agent is blown directly into the gasifier through the perforated plate, depending on the type of coal, for example, caking coal may be used. In this case, the perforated plate becomes clogged and stable and good operation cannot be performed, but with the present invention, such a risk does not occur at all.

Furthermore, the gasifying agent is tangentially blown into the gasifying agent blowing chamber, which has a circular cross section, so that it is supplied into the gasifier in a swirling flow. The gasifier is shaped like a truncated cone with a bottom convergence, so that the cross-sectional gas velocity gradually decreases as it goes upward. It is possible to achieve more stable and better operation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional two-stage gasification type gasifier, Fig. 2 is an overall system diagram of an embodiment of the present invention, and Fig. 3 is an overall system diagram of another embodiment of the present invention. Figure 4 is an overall system diagram when the present invention is used in a boiler.
FIG. 5 is an overall system diagram when the present invention is applied to a plurality of boilers, heating furnaces, hot blast stoves, etc. 10...Gasifier, 11...Throat, 12...Gasifying agent blowing chamber, 15...Char storage tank, 16...
Damper, 17... Chute, 18... Cheer combustion furnace, 24... Air preheater, 40... Cheer hopper, 41... Screw conveyor, 42... Mixer, 50... Gasifier, 51... Residual heat boiler,
52... Air preheater, 53... Boiler, 54...
Economizer, 55...Dust collector, 56...Chimney, 5
7...Deaerator, 58...Water pump, A...Air (gasification agent), S...Steam (gasification agent).

Claims (1)

[Claims] 1. A jet-flow gasification furnace with a truncated conical shape that narrows at the bottom, and a gasification agent injection chamber with a circular cross-section that is connected to the bottom of the gasification furnace and into which the gasification agent is blown tangentially. , a chir combustion furnace connected to the blowing chamber, a chir transfer means for transferring sinter that has fallen from the gasification cutting furnace to the gasifying agent blowing chamber to the chiar combustion furnace; a gasifying agent heating means for heating the gasifying agent blown into the gasifying agent blowing chamber by the generated chiar combustion gas, the gasifying agent heating means chiring the gasifying agent. A coal gasification apparatus having a chir combustion furnace, characterized by comprising an air preheater for exchanging heat with gas or a mixer for mixing chire combustion gas with a gasifying agent.