KR101322107B1 - High Efficient Coal Gasfier - Google Patents

Abstract

The present invention relates to a coal gasifier, disposed on the side wall of the first reactor, the raw material and gas supply port for supplying the gas of the raw coal and steam and oxygen into the first reactor; A syngas flow tube disposed on an upper portion of the first reactor and discharging a primary syngas formed by a gasification reaction in the first reactor; And a fractionation bed reactor disposed under the first reactor and including a slag outlet for discharging slag which is a gasification reaction by-product from the first reactor. A raw material supply port for supplying raw coal to the second reactor; And a syngas outlet disposed above the second reactor, the syngas outlet for discharging secondary syngas generated by the gasification reaction in the second reactor, wherein the fluidized bed reactor is the fractionated bed reactor. It is disposed on top of the fractionation bed reactor through the syngas flow tube of, the coal gasifier is provided by the syngas flow tube is supplied with the primary syngas into the fluidized bed reactor.

Description

High Efficient Coal Gasfier with Low Coal Application

The present invention relates to a coal gasifier, and more particularly to a coal gasifier suitable for application to low coal.

Conventional coal gasifiers include fixed bed reactors such as Lurgi, fluidized bed reactors such as SES, and fractionated bed reactors adopted by most companies such as Shell, GE, and SIMMENS in the commercialization stage for coal gasification. Each reactor type has its advantages and disadvantages.

The fractionated bed reactor applied to most coal gasifiers has a structure as shown in FIG. 1, and the reactor is operated at a high temperature, and high temperature syngas is discharged from the reactor. There is a problem that is low.

Meanwhile, in the conventional fluidized bed reactor as shown in FIG. 2, the reaction temperature is maintained at about 950 to 1000 ° C., which is sufficiently lower than around 1300 ° C., which is the melting temperature of ash, to perform gasification of coal. As a result, when the surface of the coal particles is partially melted, the particle size is increased due to the aggregation between the particles and the particle size is increased, thereby preventing the particle from falling down and collapsing the fluidized bed. Due to such a low operating temperature, the heat loss is smaller than that of the fractionated bed reactor, the gasification efficiency is high, and thus there is an advantage also suitable for using low-grade coal.

However, such a fluidized bed reactor causes a collapse of the fluidized bed when the operating temperature increases, so that stable operation cannot be achieved. Therefore, strict management of the operating temperature is required. In addition, since the reaction temperature is low, there is a problem that tar is contained in the syngas discharged due to the generation of tar, and the unreacted carbon is discharged to the bottom of the reactor together with the solid ash, so that the carbon conversion rate is lower than that of the fractionated bed gasifier. Has a problem.

Furthermore, the solid bed is discharged from the fluidized bed reactor due to the discharge of slag in the fractionated bed reactor, which is not environmentally clean, and there is a limited problem in recycling.

Japanese Laid-Open Patent Publication No. 05-032977

In the present invention, to overcome the disadvantages of the fluidized bed reactor and the fractionated bed reactor, even when using low-grade coal to provide a coal gasifier having a relatively low reduction in gasification efficiency.

In another embodiment of the present invention, by suppressing the generation of fine dust as the reaction by-products, and to produce a slag to provide an environmentally friendly gasifier.

The present invention relates to a coal gasifier, according to an embodiment of the present invention, disposed on the side wall of the first reactor, the raw material and gas supply port for supplying the gas of the raw coal and steam and oxygen into the first reactor; A syngas flow tube disposed on an upper portion of the first reactor and discharging a primary syngas formed by a gasification reaction in the first reactor; And a fractionation bed reactor disposed under the first reactor and including a slag outlet for discharging slag which is a gasification reaction by-product from the first reactor. A raw material supply port for supplying raw coal to the second reactor; And a syngas outlet disposed above the second reactor, the syngas outlet for discharging secondary syngas generated by the gasification reaction in the second reactor, wherein the fluidized bed reactor is the fractionated bed reactor. It is disposed on top of the fractionation bed reactor through the syngas flow tube of, the coal gasifier is provided by the syngas flow tube is supplied with the primary syngas into the fluidized bed reactor.

In a second embodiment of the present invention, the coal gasifier may be supplied back to the fractionation bed reactor fine particles removed by a cyclone.

According to a third embodiment of the present invention, the fluidized bed reactor may have an operating temperature in the range of 1000 to 1100 ℃.

By applying the gasifier of the present invention it is possible to minimize the unreacted carbon component discharged, it is possible to reduce the emissions of the carbon component in the ash discharged in the form of slag compared to the existing fluidized bed reactor even when using low-grade coal.

In addition, by applying the gasifier of the present invention it is possible to overcome the environmental problems by discharging the solid ash of the molten slag quenched with water.

Furthermore, the thermal efficiency is higher than that of a conventional fractionated bed reactor, so it is suitable for gasification using lower coal.

1 is a view schematically showing a fluidized bed reactor structure in a conventional gasifier.
2 is a view schematically showing a fractionation bed reactor structure in a conventional gasifier.
3 is a gasifier according to one embodiment of the present invention, a diagram showing a gasifier equipped with a fluidized bed reactor on a fractionation bed reactor and a schematic gasification process accordingly.

The present invention is to provide a coal gasifier with high gasification efficiency even if low coal is used for gasification of coal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the following description and the accompanying drawings are for illustrative purposes only, and the present invention is not limited thereto.

As shown in FIG. 3, the coal gasifier provided in the present invention has a two-stage reactor type in which a fractionation bed reactor is disposed at the bottom and a fluidized bed reactor is disposed at the top. By using a two-stage reactor having such a structure, it is possible to simultaneously solve each of the disadvantages of using the fractionated bed reactor and the fluidized bed reactor alone.

The fractionated bed reactor is a main reactor of the gasifier according to the present invention, and the fractionated bed reactor and the side have a plurality of raw material supply ports supplied with coal, steam, and oxygen, which are raw materials for gasification, and melted after gasification in the lower part of the reactor. It has a molten slag outlet for discharging slag, and further has a primary syngas outlet for discharging primary syngas generated by gasification of coal at the top of the reactor.

The fractionated bed reactor has characteristics similar to those of a commonly used fractionated bed reactor, and the operating temperature therein is operated at a temperature higher than the melting temperature of ash. Therefore, the operating temperature of the fractionation bed reactor may be different depending on the type of coal, it is preferable to maintain the internal temperature from 1350 ℃ to 1500 ℃. Ash can be melted by gasifying coal in the above temperature range, so that molten slag can be formed, and it can be recycled.

Coal and gas which are target raw materials for syngas production are supplied into the fractionation bed reactor. In this case, the supplied gas may inject high temperature steam and oxygen.

Coal is gasified in the fractionation bed reactor to form a synthesis gas including carbon monoxide and hydrogen, and the formed synthesis gas is discharged through an upper portion of the fractionation bed reactor. On the other hand, the ash formed by the gasification of coal is melted to form molten slag, which is discharged through the bottom of the fractionation bed reactor.

The fluidized bed reactor is disposed above the fractionated bed reactor. The fluidized bed reactor serves as a secondary reactor in the gasifier of the present invention, the fluidized bed reactor includes a raw material supply port for charging coal as a raw material, secondary synthesis gas outlet for discharging the secondary synthesis gas on the top Has

The fractionation bed reactor and the fluidized bed reactor are connected to each other by a flow tube for the flow of the primary synthesis gas formed in the fractionation bed reactor, the primary synthesis gas formed in the fractionation bed reactor through the flow tube is located at the top of the fractionation bed reactor It is fed to a fluidized bed reactor placed. In this case, the primary synthesis gas supplied to the fluidized bed reactor from the fractionated bed reactor, which is the main reactor, is a high temperature of 1300 ° C. or more, and the pyrolysis and gasification of coal supplied into the fluidized bed reactor is supplied by reusing the primary synthesis gas into the fluidized bed reactor. Can induce a reaction. Therefore, it is not necessary to supply a separate gas for the pyrolysis and gasification reaction of coal. Furthermore, in the fluidized bed reactor, the primary synthesis gas can be used to induce the pyrolysis reaction and gasification reaction, so that the thermal efficiency can be improved as compared with the conventional fractionated bed reactor. We can plan.

In addition, the upper fluidized bed reactor of the two-stage reactor according to the present invention can achieve a smooth operation even if maintained at about 1000 ~ 1100 city higher than the reaction temperature of the conventional single fluidized bed reactor of about 950 ~ 1000 ℃. Because if a hot spot occurs and the surface of some particles melt and cause agglomeration between particles, the agglomerated particles will fall to the lower fractionation layer reactor instead of being discharged to the outside, where the dropped particles will be added. Pyrolysis and gasification reaction of not only causes carbon to be removed, but also ash is finally melted and discharged, thereby preventing the fluidized bed from collapsing due to melting of particles in the conventional fluidized bed reactor. It can prevent.

Furthermore, since the reaction temperature of the upper fluidized bed reactor according to the present invention is higher than the conventional single fluidized bed reactor, the generation of tar can be suppressed.

On the other hand, the secondary synthesis gas is completed in the upper fluidized bed reactor is discharged through the outlet of the reactor top. In this case, the discharged secondary synthesis gas may include fine particles such as fine powder, and by collecting these fine particles, only the synthesis gas free of impurities may be discharged from the gasifier to obtain a desired synthesis gas.

On the other hand, the fine particles collected by the cyclone may be re-introduced into the bottom fractionation bed reactor. The fine particles re-introduced into the fractionation layer reactor may increase the carbon conversion rate by using unreacted carbon components in pyrolysis and gasification reactions, and further, the ash may be melted and discharged into the fractionation layer reactor in the form of slag. The fine particles may be supplied into the reactor through the raw material and the gas supply port into the fractionation bed reactor, may be supplied through a separate inlet.

The discharged molten slag does not contain an unreacted material is environmentally clean, and can be stably recycled to cement or the like.

Therefore, by using the gasifier of the present invention, problems such as tar discharge, low carbon conversion rate, and solid ash discharge, which are disadvantages of the conventional fluidized bed reactor, can be solved, and low thermal efficiency and low coal use, which are disadvantages of the conventional fractionated bed reactor, are also used. This can solve the problem of additional thermal efficiency degradation.

Hereinafter, the present invention will be described more specifically by way of examples.

Example

Comparative Example  One

Coal was charged into the reactor of the gasifier having a fluidized bed reactor, and the synthesis | combination gas was obtained by maintaining the reactor internal temperature at 950 degreeC, supplying steam and oxygen to the lower part. The obtained synthesis gas was discharged and collected to the top of the reactor, and the solid ash of the reaction was discharged through the outlet of the bottom of the reactor.

The solid ash discharged through the outlet of the reactor bottom was analyzed, the carbon content was 3% of the solid ash weight. The tar content was analyzed in the obtained synthesis gas, and a small amount of tar was included. On the other hand, the conversion rate to the gasified synthesis gas was calculated for the coal supplied as the raw material, and the conversion rate was 68%.

Comparative Example  2

After charging coal into the reactor through a raw material supply pipe installed at the reactor side of the gasifier having the fractionation bed reactor, steam and oxygen were supplied together under similar supply conditions, and then the temperature inside the reactor was maintained at 1400 ° C. The gasification reaction was carried out to obtain a gas. The obtained synthesis gas was discharged and collected to the top of the reactor, and the molten slag in which the reaction was completed was discharged through the outlet of the bottom of the reactor.

The conversion rate to gasified synthesis gas was calculated for the coal supplied as a raw material, and the gasification efficiency was found to be 65% which is slightly lower than that of Comparative Example 1.

Example  One

A fluidized bed reactor was installed on top of the fractionated bed reactor. At this time, a flow tube for gas flow is formed between the fractionation bed reactor and the fluidized bed reactor, and about 30% of the total charged coal is charged in the fluidized bed reactor.

Steam and oxygen were injected to the side of the fractionation bed reactor with coal as a gasification raw material under the same conditions as in Example 2, and the pyrolysis and gasification of coal were carried out by maintaining the reactor internal temperature at 1400 ° C. to obtain a gas. The obtained syngas was fed into the fluidized bed reactor through a flow tube above the fractionated bed reactor. At this time, the synthesis gas was about 1300 ℃ temperature. Meanwhile, the molten slag in which the reaction was completed was discharged to the bottom of the reactor.

The temperature in the fluidized bed reactor was maintained at 1100 ° C. to induce pyrolysis and gasification reaction of coal, and the obtained synthesis gas was discharged through the outlet of the upper part of the reactor, and then fine particles contained in the synthesis gas were removed through a cyclone, followed by synthesis The gas was collected.

On the other hand, the fine particles removed by the cyclone was supplied through the coal and gas supply pipe.

The conversion rate to the gasified synthesis gas collected for the charged raw materials was calculated, the gasification efficiency was 75% higher than the gasification efficiency of Comparative Examples 1 and 2.

On the other hand, the carbon content in the molten slag discharged from the gasifier was analyzed, it was present in less than 1%.

As can be seen from Example 1 and Comparative Examples 1 and 2, when lower coal is used, the gasification rate can be improved by using the gasifier according to Example 1, as well as the tar content in the synthesis gas. It can be seen that it can be reduced, so that a more efficient gasification reaction can be performed.

In addition, since the slag can be produced as a residue during the gasification process to suppress the generation of fine dust, reprocessing is unnecessary, and the obtained slag can be recycled and environmentally friendly.

In addition, the high gasification efficiency and the low temperature of the final gasifier exhaust synthesis gas is suitable for the use of low reactivity coal is highly reactive.

Claims (3)

A raw material and gas supply port disposed on a side wall of the first reactor and configured to supply gas of raw coal, steam, and oxygen into the first reactor; A syngas flow tube disposed on an upper portion of the first reactor and discharging a primary syngas formed by a gasification reaction in the first reactor; And a fractionation bed reactor disposed under the first reactor and including a slag outlet for discharging slag which is a gasification reaction by-product from the first reactor. And
A raw material supply port for supplying raw coal to the second reactor; And a syngas outlet disposed above the second reactor, the syngas outlet for discharging secondary syngas generated by the gasification reaction in the second reactor.
The fluidized bed reactor is disposed above the fractionated bed reactor through a syngas flow tube of the fractionated bed reactor, and the primary syngas is supplied into the fluidized bed reactor by the syngas flow tube.
The coal gasifier of claim 1, wherein the coal gasifier comprises a cyclone, wherein the cyclone collects fine particles from the secondary syngas discharged from the syngas outlet and supplies the fine particles to the fractionation bed reactor. Gasifier.
The coal gasifier of claim 1, wherein the fluidized bed reactor has an operating temperature of 1000 to 1100 ° C.

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