JPH10251670A - Gasifier for plastic and coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasifier for plastics and coal, whereby the rate of gasification after the combustion of the volatile matter of coal can be heightened, the loss resulting from the latent heat of vaporization of water can be compensated, and the gasification is accelerated to heighten the efficiency of gasification. SOLUTION: This invention provides a down-flow type gasifier 10 in which coal is slurred with water, and the formed slurry is fed into the gasifier by means of a high-pressure pump and is gasified and which consists of a combustion reactor 12 in which the volatile matter contained in the coal is at least partially burn, and a gasification reactor 14 installed so as to communicate with the lower section of the reactor 12 and further provided with a feeder 16 for feeding plastics into the lower section of the reactor 12 or the upper section of the reactor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasifier for plastics and coal, and more particularly to a coal gasifier using plastics as a reaction accelerator.

[0002]

2. Description of the Related Art As a power generation apparatus using coal, heavy oil, orimulsion and the like as a fuel, a gasification combined cycle power generation apparatus for gasifying fuel to generate power has been developed. FIG. 4 shows an example of such an integrated coal gasification combined cycle device, which includes a gasifier 1, an exhaust heat recovery device 2, a desulfurization device 3, a dust removal device 4, a gas turbine power plant 5, a steam turbine power plant 6, and the like. Then, the fuel (coal) is gasified in the gasifier 1, heat is recovered in the exhaust heat recovery device 2 to a temperature suitable for desulfurization, and desulfurized in the desulfurization device 3.
The dust is removed by the dust removing device 4, the gasified gas is burned by the gas turbine power generating device 5, the power is generated by the gas turbine, the steam is generated by the exhaust gas, and the steam turbine also generates the power.

On the other hand, a coal gasifier is a device that pyrolyzes and reforms coal to convert it into a gas such as H ₂ , CO, CH _4, etc. Hearth,
Melt bed furnaces have already been developed. Among them, the spouted bed furnace is a system in which pulverized coal, oxygen, and steam are jetted together from the same burner into the furnace to simultaneously perform combustion and gasification reaction. Since the inside of the furnace becomes a high temperature of about 1000 ° C., the generated gas becomes a synthesis gas containing H ₂ and CO as main components, and the ash becomes slag (molten ash), flows down to the furnace bottom, and is extracted outside the furnace. In such a spouted bed furnace, high-temperature gasification is performed and the carbon conversion rate increases, but at the same time, the sensible heat loss of the crude gas also increases. Therefore, in order to improve the gasification efficiency, it is necessary to reduce the sensible heat loss of the crude gas and the heat loss of the furnace wall.

FIG. 5 is a structural view of a Texaco furnace which is one of the spouted bed furnaces, 7 is a slurry tank, 8 is a gasification furnace main body, 8a is a burner, and 8b is a slag water cooling chamber. The Texaco furnace is a down-flow type coal gasifier, which slurries coal with water and supplies it into the furnace with a high-pressure slurry pump to gasify the coal. That is, the coal is pulverized to about 70 μm, adjusted to a slurry of 60 to 70%, and pressed into the furnace.
The pressurized slurry is injected downward together with O ₂ from the nozzle at the furnace top, and forms a high-temperature combustion flame of about 1770 K in the furnace to be gasified. The ash is melted into slag, flows down the furnace wall of the refractory brick into a water tank at the bottom of the furnace, is granulated, and is extracted outside the furnace.

[0005]

In the above-mentioned conventional coal gasifier, coal is supplied into the furnace alone (powder state) or as a slurry mixed with water. But,
The main component of the coal is C—H—O, and as shown schematically in FIG.
Is also extremely low at several percent. Therefore, when coal is gasified, the reactivity of the volatile components is high, but the reactivity of the char remaining after the volatile components reaction is low. In this state, a synthesis gas containing H ₂ and CO as main components is generated. There was a problem that the reaction rate during the reaction was low.

In the case of simple coal, it is difficult to supply coal into a high-pressure furnace. On the other hand, in the case of coal slurry, it can be supplied into a high-pressure furnace and the reactivity can be increased by using H of water (H ₂ O), but the latent heat of steam is deprived by moisture. There is a problem that the gasification reaction rate does not increase due to a large heat loss.

The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a gasification apparatus capable of increasing a gasification reaction rate of a main component of coal char after burning of volatile matter (volatile matter) of coal. Another object of the present invention is to provide a gasification apparatus that can compensate for the loss due to the latent heat of evaporation of water, promote the gasification reaction, and further increase the gasification efficiency.

[0008]

Means for Solving the Problems Plastics are generally composed mainly of carbon, hydrogen and oxygen, and have a linear structure as shown in FIG. 6B. Easily decomposes and the oxidation reaction proceeds easily. On the other hand, coal is also a kind of macromolecule whose main components are carbon, hydrogen and oxygen, but has a large molecular weight, a large number of cyclic structural components such as a benzene ring as described above, and a small hydrogen content. There is a feature that is extremely small as%. For this reason, coal, especially coal char component, has lower reactivity than plastic.

The inventors of the present invention pay attention to the above-mentioned difference in properties between coal and plastic, and improve the reaction efficiency by using highly reactive plastic as a kind of reaction accelerator to contribute to the gasification reaction. I focused on. However, if coal and plastic are simply mixed and supplied into the furnace, highly reactive plastic will burn in a short period of time in the early stage of the reaction together with the volatile components of the coal, resulting in a furnace temperature distribution suitable for the gasification reaction. Things get more difficult. Therefore, the present inventors increased the radical concentration by decomposing the hydrogen groups of the plastic by adding plastic at a stage where volatile components react and coal char became a main component, instead of mixing with coal from the beginning. The inventor of the present invention devised that the decomposed carbon of plastic becomes a reaction nucleus to accelerate the gasification reaction. The present invention is based on such a new finding.

That is, according to the present invention, in a down-flow type gasifier in which coal is slurried with water and supplied into a furnace by a high-pressure slurry pump to gasify, the volatile components contained in the coal are at least partially reduced. And a gasification reactor installed in communication with the lower part of the combustion reaction furnace and in which a gasification reaction proceeds.Furthermore, plastic is provided in an intermediate portion between the combustion reaction furnace and the gasification reaction furnace. A plastic and coal gasifier is provided, comprising a plastic feeder for feeding.

According to the structure of the present invention described above, the plastic is introduced into the area outside the volatile combustion zone, the radical concentration is increased by the hydrogen group (H) of the plastic, and the carbon group (C) of the plastic is increased. It is devised to increase the concentration of reaction nuclei. That is, a combustion reactor in which volatiles contained in coal are burned and a gasification reactor in which a gasification reaction proceeds are separated, and plastic is supplied by a plastic supply device to an intermediate portion between the combustion reactor and the gasification reactor. By adding plastic to the stage where coal char is the main component, the radical concentration due to the hydrogen groups of the plastic is increased, and the decomposition carbon or hydrogen of the plastic becomes the reaction nucleus to promote the gasification reaction of the coal char main component. Therefore, highly reactive coal gasification becomes possible.

According to a preferred embodiment of the present invention, the plastic supply apparatus comprises a plastic melting furnace for melting waste plastic, and a plastic pressurizing furnace for pressurizing and supplying the melted plastic. With this configuration, molten plastic can be supplied stably under high pressure,
In addition, waste plastic can be used, contributing to environmental conservation.

According to another preferred embodiment, the plastic supply device includes a plastic pulverizer for pulverizing waste plastic and a plastic supply machine for supplying pulverized plastic. With this configuration,
Plastics can be directly supplied as powder, and waste plastics can be used as well, contributing to environmental conservation.

[0014]

Preferred embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common portions are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is a configuration diagram of a gasifier according to the present invention.
In this figure, a gasification apparatus 10 of the present invention is a down-flow type coal gasification furnace in which coal is slurried with water, supplied into a furnace with a high-pressure slurry pump, and gasified.

Further, the gasification apparatus 10 of the present invention is installed in communication with a combustion reaction furnace 12 in which volatile components contained in coal are at least partially burned and a lower part of the combustion reaction furnace 12, and the gasification reaction proceeds. A gasification reactor 14 is provided, and the two reaction furnaces 12 and 14 constitute a gasification furnace main body. As shown in this figure, the inner shape of the reactors 12 and 14 may be configured such that the middle part is narrowed and can be clearly separated.
Alternatively, the two reactors 12 and 14 may be formed integrally and cannot be separated. In FIG. 1,
Reference numeral 19 denotes a gas cooler provided with a radiation heat exchanger, and reference numeral 20 denotes a slag cooling chamber in which cooling water is stored.

Further, the gasifier 10 of the present invention includes a plastic supply device 16 for supplying plastic to an intermediate portion between the combustion reactor 12 and the gasification reactor 14. Further, in this embodiment, the plastic supply device 16
Plastic melting furnace 17 for melting waste plastic
And a plastic pressure furnace 18 for pressurizing and supplying the melted plastic. Plastic melting furnace 17
Is designed to burn a part of the gasified gas generated in the gasification furnace as fuel gas to heat and melt the waste plastic. Further, the plastic pressurizing furnace 18 keeps or heats the molten plastic by high-pressure steam generated in the radiant heat exchanger 19 and pressurizes the molten plastic by a pressurized gas (compressed air or nitrogen gas) to gasify the plastic. The apparatus 10 is supplied. With this configuration, the molten plastic can be stably supplied under high pressure, and the waste plastic can be used, thereby contributing to environmental conservation.

FIG. 2 is another configuration diagram of the gasifier according to the present invention. In this figure, a plastic supply device 1
6 comprises a plastic crusher 13 for pulverizing the waste plastic and a plastic feeder 15 for supplying the pulverized plastic. Lock hoppers 15a are provided above and below the plastic feeder 15, and by opening and closing the lock hopper 15a, powder can be supplied into the furnace under pressure. Other configurations are the same as those in FIG.
According to this configuration, plastic can be directly supplied into the furnace under pressure by increasing the surface area by increasing the surface area of the plastic as a powder, and similarly, waste plastic can be used and can contribute to environmental conservation.

FIG. 3 is a diagram showing a temperature distribution in the gasification furnace according to the present invention. In this figure, the horizontal axis represents the temperature, and the vertical axis represents the position from the upper part of the combustion reactor 12 to the lower part of the gasification reactor 14, and the two-dot chain line in the figure is a conventional example, and the solid line is an example of the present invention. Is shown. As shown in this figure, in a conventional coal gasifier, in a region where the volatile components contained in the coal burn (in the present invention, a combustion reactor), the temperature of the volatile components rises particularly at the inlet, but the volatile components burn. In the region where coal char is the main component after completion of combustion for the minute (a gasification reactor in the present invention), the temperature of the generated gas is rapidly lowered due to the gasification reaction that generates H ₂ and CO, and the efficiency is improved. It becomes difficult to maintain the gasification reaction.

On the other hand, in the present invention, a region in which volatile components contained in coal are burned (the combustion reactor 12 of the present invention) and a gasification reactor 14 in which the gasification reaction proceeds are divided, and the combustion reactor By supplying plastic to the intermediate portion between the gasification reactor 12 and the gasification reactor 14, the radical concentration due to the hydrogen groups of the plastic is increased, and the temperature of the region where the coal char is the main component (the gasification reactor of the present invention) is gasified. Maintaining a high temperature suitable for the reaction, the decomposed carbon or hydrogen of the plastic serves as a reaction nucleus to promote the gasification reaction, enabling coal gasification with high reaction efficiency.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0021]

As described above, the plasticizer and coal gasifier of the present invention can increase the gasification reaction rate of the main component of coal char after burning volatile matter (volatile matter) of coal, and increase the water content. Has an excellent effect of compensating for the loss due to latent heat of vaporization and promoting the gasification reaction to further increase the gasification efficiency.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a gasifier according to the present invention.

FIG. 2 is a configuration diagram of another gasifier according to the present invention.

FIG. 3 is a diagram showing a temperature distribution in a gasification furnace according to the present invention.

FIG. 4 is a diagram showing an example of an integrated coal gasification combined cycle device.

FIG. 5 is a structural diagram of a Texaco furnace which is one of the spouted bed furnaces.

FIG. 6 is a diagram showing the molecular structures of coal and plastic.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gasification furnace 2 Exhaust heat recovery apparatus 3 Desulfurization apparatus 4 Dust removal apparatus 5 Gas turbine power generation apparatus 6 Steam turbine power generation apparatus 7 Slurry tank 8 Gasification furnace main body 8a Burner 8b Slag water cooling room 10 Gasification apparatus 12 Combustion reaction furnace 13 Plastic Crusher 14 Gasification reactor 15 Plastic feeder 16 Plastic feeder 17 Plastic melting furnace 18 Plastic pressurization furnace 19 Radiant gas cooler 20 Slag cooling chamber

Claims (3)

[Claims] 1. A down-flow type gasifier for slurrying coal with water and supplying it into a furnace by a high-pressure slurry pump to gasify the coal, wherein a volatile component contained in the coal is at least partially burned in a combustion reactor. And a gasification reactor installed in communication with a lower part of the combustion reactor and a gasification reaction proceeds, and a plastic supply device for supplying plastic to an intermediate portion between the combustion reactor and the gasification reactor. A plastic and coal gasifier comprising: 2. The plastic supply apparatus according to claim 1, wherein the plastic supply device comprises a plastic melting furnace for melting the waste plastic and a plastic pressurizing furnace for pressurizing and supplying the melted plastic. Gasifier. 3. The plastic supply device comprises: a plastic crusher for pulverizing waste plastic; and a plastic supply device for supplying the pulverized plastic.
The gasifier according to claim 1, characterized in that: