JP2001059092A - Gas flow bed coal gasifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably operate a coal gasifier, and further control the operation in a stable and easy manner even in the case where the feedings of raw material and char are changed. SOLUTION: The burners ejecting an oxidizing agent into gasifying parts 21 are evenly distributed along the circumference of a pressurized container 22 constituting the gasifying parts 21 and placed in such a manner that the directions of ejections form tangential lines to a virtual circle 41 on a horizontal plane in the furnace, and equal amounts of the oxidizing agent are fed into the gasifying parts 21 from each of oxidizing agent-ejecting positions. Further, when the burners ejecting finely pulverized solid carbonaceous raw material into the gasifying parts 21 are placed on the upper stage and the lower stages separately, the oxidizing agent ejected from all the burners placed on at least the lower stage is supplied from an oxidizing agent- supplying tube 1 of one system, and a valve 34 and a flow meter 33 for controlling the flow rate in the oxidizing agent-supplying tube 1 are placed, and at the same time an oxidizing agent-distributor 28 is placed on the downstream side of the oxidizing agent-supplying tube 1 to distribute and supply equal amounts of the oxidizing agent into each of the burners placed on the lower stage via oxidizing agent-supplying branches 7 for the lower burners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-bed coal gasifier for gasifying a fine solid carbonaceous material represented by coal using an oxidizing agent such as oxygen or air.

[0002]

2. Description of the Related Art Various types of furnaces for gasifying solid carbonaceous raw materials such as coal have been proposed, including a fixed bed, a fluidized bed, and a gas bed. Among these methods, the gas-bed coal gasifier converts the raw material into fine powder and an oxygen-containing gas (oxidizing agent) such as oxygen or air at a temperature higher than the melting temperature of the raw ash (about 13 ° C.).
(00 to 1600 ° C) to gasify and convert ash into slag without leaching of harmful components. Therefore, compared to other systems, gasification efficiency is high, applicable coal types are wide, environment It has features such as excellent compatibility. Regarding the gas-bed gasification method, see, for example, JP-A-60-65094.
No. 6,086,045.

A general gas-bed gasification furnace will be described below. The finely divided solid carbonaceous material such as coal is pulverized by a pulverizer in a previous process, then pressurized and conveyed by an inert gas such as nitrogen, and sent to a raw material distributor through a raw material supply pipe. Upper coal burner (hereinafter referred to as upper burner) installed in multiple units at the upper and lower stages through the supply branch pipe
And to the lower coal burner (hereinafter referred to as the lower burner). The supply amount of the oxidizing agent is controlled by separate valves and flow meters for the upper stage and the lower stage, respectively, and is sent to the upper burner and the lower burner, respectively. The raw material supplied to the gasification furnace at a higher temperature and a higher pressure than the upper and lower burners is gasified by an oxidizing agent, and the combustibles are converted into a gas rich in carbon monoxide and hydrogen and passed through a product gas outlet pipe. The ash is sent to the heat recovery section of the process, etc., and the ash is converted into molten slag, dropped into the slag cooling section at the bottom of the gasification furnace, and discharged out of the furnace from the slag discharge pipe as granulated slag.

[0004] The char containing a part of slag and unburned matter passes through a product gas take-out pipe together with the product gas, is collected by a dust removal device in the downstream, is sent to a char burner, and is sent to the coal burner. The oxidizing agent is supplied to the gasification furnace together with the oxidizing agent supplied at a flow rate controlled by a valve and a flow meter which are different from the valve and the flow meter for controlling the oxidizing agent. The lower burner and the char burner are installed such that their axis (the oxidizing agent ejection direction) is tangent to a circle (virtual circle) imagined concentrically with the gasifier on the horizontal plane inside the furnace, and the The raw material, the char, and the oxidizing agent are mixed, and a swirling flow is formed in the furnace so that the residence time of the raw material in the furnace required for the gasification reaction can be extended.

The oxidizing agent supplied into the furnace firstly partially oxidizes the raw material and reacts with already gasified carbon monoxide and hydrogen to form carbon dioxide and water, and secondly, it is relatively slow. It reacts with the carbon in the feed at a rate to gasify. That is, in order to obtain a high gasification efficiency, it is necessary to sufficiently mix the raw material, the char and the oxidizing agent, and to form a swirling flow for extending the residence time of the raw material in the furnace.

A method for efficiently and stably supplying coal, char, and oxidant into a gasification furnace is disclosed in, for example,
-246287 and JP-A-5-25274. In the publications disclosed in these publications, a coal supply burner and a char supply burner are alternately arranged on a circumference in a lower supply section of a gasification furnace, and a plurality of burners installed in each of upper and lower stages have their respective axial lines. Are arranged in a direction tangential to the virtual circle in the furnace to form a swirling flow, and the supplied coal, char and oxidizing agent are sufficiently mixed to increase the reactivity.

[0007]

The above publication does not describe the amount of oxidant supplied from each burner. For example, if the amount of oxidant supplied to a coal burner and a char burner installed in the lower stage is different, In addition, the temperature distribution in the furnace becomes uneven, and a good gasification reaction field cannot be obtained. Furthermore, when the oxidizer supplied to the char burner is extremely small compared to the oxidizer supplied to the coal burner, a good swirl flow is not formed and the mixing property is deteriorated. Conversely, if an excessive amount of oxidizing agent is supplied to form a good swirling flow, the burner may be burned, and stable operation cannot be performed. In addition, when the plant throughput is increased, it is necessary to increase the number of burners in order to maintain the swirling flow, which is not only uneconomical, but also makes it more difficult to transport the raw materials. On the other hand, in order to maintain the swirling force without increasing the number of burners in consideration of economy, it is necessary to extremely increase the ejection speed of the raw material and the oxidant into the furnace, resulting in significant damage to the furnace wall. . Furthermore,
Since the oxidizer is sent to the coal burner and char burner by separate systems, the oxidizer supply control becomes multiple, and if the supply of coal and / or char fluctuates, the oxidizer supplied to the coal burner and char burner Since the amounts are individually controlled, complicated operation control is required.

An object of the present invention is to stably and easily control the operation of a coal gasifier even if the supply of raw materials and char fluctuates.

[0009]

According to the present invention, in order to achieve the above object, the oxidizing agent supplied to the gasification section is uniformly distributed in the circumferential direction of the furnace in each of the upper and lower stages, The jet direction is set so as to be tangent to a virtual circle on a plane in the furnace, and an equal amount of oxidant is supplied to the gasification unit from each position of the oxidant jet. In particular,
The oxidant supply to the oxidant ejection position including the lower burner and the char burner arranged in the lower stage is arranged at one end of the oxidant supply pipe provided with a flow control means and at the downstream end of the oxidant supply pipe. The oxidizer distributor and the oxidizer distributor and the oxidizer ejection position are individually connected to each other through an oxidizer supply branch pipe, and the oxidant distributor is uniformly distributed to the oxidant supply branch pipe. Configure to distribute.

[0010] The formation of a good swirling flow in the furnace largely depends on the method of supplying the oxidizing agent having the highest swirling force. According to the present invention, a plurality of oxidant supply positions are evenly dispersed in the circumferential direction of the furnace, and a circle (virtual) concentric with the gasification furnace on a horizontal plane in the furnace from each oxidant supply position. In the tangential direction of the circle), an equal amount of the oxidizing agent is supplied, so that a good swirling flow is formed in the gasification section, and the temperature distribution in the furnace becomes uniform, so that a good gasification reaction field is formed. can get. Further, since an equal amount of oxidant is sent to the coal burner and the char burner, only one oxidant supply control in the lower stage is required, and operation control is easy and economical. Further, even if the supply of coal and / or char fluctuates to increase or decrease the amount of the oxidizing agent, it is easy to maintain a good swirling flow.

[0011]

(Embodiment 1) FIG. 1 is a longitudinal sectional view showing a schematic configuration of a coal gasifier according to Embodiment 1 of the present invention, and FIG. 2 is a line BB of FIG. FIG.

The illustrated coal gasifier includes a cylindrical pressure vessel 22 constituting a gasifier main body, a slag cooling section 25 formed at the bottom of the pressure vessel 22 and filled with cooling water, and a slag cooling section 25. Refractory material 42 on the inner surface of the pressure vessel 22
And a plurality of upper raw material supply burners (hereinafter, referred to as upper burners) which are arranged above the gasification unit 21 so as to penetrate the wall surface of the pressure vessel 22 and have the axis substantially horizontal. ) 4, a plurality of lower raw material supply burners (hereinafter, referred to as lower burners) 5 penetrating the wall surface of the pressure vessel 22 below the gasification section 21 and arranged with the axis substantially horizontal, and substantially the same as the lower burners 5. Pressure vessel 22 at height
And a plurality of char burners 10 which are arranged so that the axis is substantially horizontal and penetrates the wall surface, and feeds a flow path of fine solid carbonaceous material such as pulverized coal which is pulverized by a pulverizer (not shown). A pipe 1, a raw material distributor 2 connected to the downstream end of the raw material supply pipe 1, a plurality of raw material supply branch pipes 3 individually connecting the raw material distributor 2 and the upper burner 4 and the lower burner 5, An upper burner oxidant supply pipe 6 having a downstream end dispersedly connected via a distributor (not shown) to the upper burner 4 with a valve 32 and a flow meter 31 interposed as control means, a valve 34 and a flow rate as flow control means A lower burner oxidant supply pipe 27 with a total of 33 interposed therein, and an oxidant distributor 28 connected to the downstream end of the lower burner oxidant supply pipe 27
And a plurality of lower burner oxidant supply branch pipes 7 for individually connecting the oxidizer distributor 28 with the lower burner 5 and the char burner 10; A collection char supply pipe 9 for returning the char collected by the dust device to the gasification unit 21 via the char burner 10; a slag discharge pipe 26 connected to the bottom of the slag cooling unit 25 for discharging slag; , Pressure vessel 2
2 which is connected to the uppermost part of the pipe 2 and guides the generated gas to the dedusting device via a heat recovery device (not shown)
3 is included.

As shown in FIG. 2, the lower burner 5 and the char burner 10 are arranged at equal intervals on the circumference of the gasification furnace, and their axes (the oxidizing agent ejection direction) are placed on the horizontal plane of the gasification section 21. A circle (virtual circle) 41 imagined concentrically with 22
Are arranged so as to form a tangent line to.

The oxidizing agent distributor 28 distributes the oxidizing agent which flows in with its flow rate controlled by the valve 34 and the flow meter 33 as flow rate controlling means to the plurality of oxidizing agent supply branch pipes 7 connected to the lower burner. It is configured as follows. The distributor of the upper burner oxidant supply pipe 6 also distributes the oxidant evenly to the connected upper burners.

A finely divided solid carbonaceous material such as coal is pulverized by a pulverizer in the previous step, and then pressurized and conveyed by an inert gas such as nitrogen. It is sent to the upper burner 4 and the lower burner 5 which are respectively provided in the upper and lower stages through the raw material supply branch pipe 3. The oxidant to the upper burner 4 is supplied to the valve 32 and the flow meter 31.
The supply amount is controlled by the control unit, and is distributed to the upper burners 4 in equal amounts by the distributor. The supply amount of the oxidant to the lower burner 5 and the char burner 10 is controlled by a valve 34 and a flow meter 33, and is evenly distributed to a plurality of lower burner oxidant supply branch pipes 7 by an oxidant distributor 28, and the lower burner 5 and the chamber burner 10. The raw material supplied to the gasification section 21 under a higher temperature and a higher pressure than the upper burner 4 and the lower burner 5 is gasified by an oxidizing agent, and the combustibles are converted into a gas rich in carbon monoxide and hydrogen, and the product gas extraction pipe 23 The ash is sent to a heat recovery unit, a dust removal device, and the like in a later process, and the ash becomes molten slag 24 and drops to a slag cooling unit 25 at the bottom of the gasification furnace. Is discharged to

The char containing a part of the slag and the unburned portion is collected by the dust removal device downstream through the generated gas extracting pipe 23 together with the generated gas, and is collected through the collecting char supply pipe 9. The oxidizing agent is sent to the char burner 10 and controlled by the valve 34 and the flow meter 33 to be supplied again to the gasification section 21 together with the oxidant supplied from the lower burner oxidant supply branch 7.

In the present embodiment, the lower burner 5 and the char burner 10 are installed so that their axes are tangent to the virtual circle 41 in the furnace as described above. And an oxidizing agent, and a swirling flow is formed to increase the residence time required for the gasification reaction. Further, the oxidizing agent supply positions are uniformly arranged in the circumferential direction, and an equal amount of the oxidizing agent is supplied from each supply position to each stage, so that a good swirling flow is formed in the furnace,
In addition, the furnace temperature distribution becomes uniform. Valve 34 and flow meter 3
3, the lower part (lower burner 5 and char burner 1)
0) is controlled, and the oxidizer distributed to the respective lower burners by the oxidizer distributor 28 is supplied by the oxidizer distributor 28. Therefore, the control of the supply amount of the oxidizer to the lower tier is a single control. Control, simplification and ease of operation. Furthermore, even if the supply amount of the fine solid carbonaceous raw material and / or the char varies, the total amount of the oxidizing agent supplied to the raw material supply burner and the char burner is controlled. Since an equal amount of oxidant is always supplied at the oxidant supply ports (each lower burner and each char burner), the vortex flow formed in the furnace is not disturbed and stable.
In addition, efficient operation is possible. (Embodiment 2) FIG. 3 shows Embodiment 2 of the present invention.
This embodiment is different from the first embodiment shown in FIGS. 1 and 2 in that a plurality of oxidizing agent nozzles for supplying only an oxidizing agent to a lower portion of the gasification section 21 (mounting level of the lower burner 5). 51, a plurality of lower burners 5 and a char burner 10
The point is that they are arranged at substantially equal intervals in the circumferential direction, and their axes (the oxidizing agent ejection direction) are tangent to the virtual circle 41 in the gasification section 21. In order to form the swirling flow, it is desirable that the total number of the oxidizing agent nozzles 51, the lower burner 5, and the char burner 10 be an even number. The oxidant nozzle 51 is also supplied with the same amount of oxidant as the other burners (lower burner 5 and char burner 10) from the oxidant distributor 28 by the lower burner oxidant supply branch 7. ing. Other components are the same as those in the first embodiment.
Therefore, the same reference numerals are given and the description is omitted.

Also in the present embodiment, the oxidizing agent supply positions are arranged at equal intervals along the circumference, and an equal amount of the oxidizing agent is supplied from each supply position. A flow is formed and the temperature distribution in the furnace is homogenized.
Further, the lower burner 5, the char burner 10, and the oxidizer nozzle 51 are supplied with an equal amount of the oxidizer whose supply is controlled by the valve 34 and the flow meter 33, so that oxidation to the lower stage is performed. The agent supply amount control is unified, and the operation becomes easy. Furthermore, even if the supply amount of the fine solid carbonaceous material and / or the char varies, the total amount of the oxidizer supplied to the lower burner, the char burner and the oxidizer nozzle is adjusted by a single control, so that the operation is not performed. Not only is it easy, but also because the same amount of oxidant is always supplied to each supply position, the turbulence of the swirling flow formed in the furnace is eliminated, and stable operation is possible. Further, as in the present embodiment, even when, for example, one cher burner is provided, the virtual circle 4
By disposing the oxidizing agent nozzle 51 at a position opposed to the position 1, disturbance of the swirling flow is avoided. Further, even when the plant capacity is large, a good swirl flow can be obtained only by increasing the number of oxidizing agent nozzles, so that it is not necessary to increase the number of raw material supply burners and / or char burners more than necessary, which is economical. . (Embodiment 3) FIG. 4 shows Embodiment 3 of the present invention.
This embodiment is different from the first and second embodiments in that an oxidizing agent nozzle 51 for supplying only an oxidizing agent is provided at a lower portion of the gasification section 21 and only the fine solid carbonaceous material is supplied with an inert gas such as nitrogen. A plurality of coal supply nozzles 52 and a plurality of char supply nozzles 53 that carry and supply only char by an inert gas such as nitrogen are provided at intervals in a circumferential direction, and Are arranged so as to be tangent to the virtual circle 41 in the gasification section 21, and the oxidizing agent nozzles 51 are arranged at equal intervals in the circumferential direction. The intervals between the coal supply nozzles 52 are also equal in the circumferential direction, and similarly, the intervals between the char supply nozzles 53 are also equal in the circumferential direction.

In this embodiment, the oxidizer is not supplied from the coal supply nozzle 52 and the char supply nozzle 53, but the oxidizer nozzles 51 are equally spaced in the circumferential direction, Oxidizer in the gasification section 2
1, a good swirling flow is formed in the furnace, and the temperature distribution in the furnace is made uniform. Further, the oxidizing agent whose flow rate is controlled by the valve 34 and the flow meter 33 is supplied to the oxidizing agent nozzle 51 in an equal amount by the oxidizing agent distributor 28, so that the oxidizing agent supply amount to the lower stage is controlled. Is performed at one place, control is simplified, and driving is facilitated.
Further, even if the supply amount of the fine solid carbonaceous raw material and / or char varies, the entire amount of the oxidizing agent supplied to the oxidizing agent nozzle is controlled at one place, so that not only the operation is easy but also the operation is easy. Since an equal amount of oxidizing agent is always supplied from each oxidizing agent nozzle, the turbulence of the swirling flow formed in the furnace is eliminated, and stable operation is possible. Furthermore, since the fine solid carbonaceous material, the char and the oxidizer are individually supplied from the coal supply nozzle 52, the char supply nozzle 53 and the oxidizer nozzle 51, respectively, a burner having a complicated structure is eliminated, and construction costs and Maintenance costs are reduced.

[0020]

According to the present invention, the operation of a coal gasifier can be controlled stably and safely and easily even when the supply of the raw material and the char fluctuates.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a main part of a first embodiment of the present invention.

FIG. 2 is a plan view taken along line BB of FIG. 1;

FIG. 3 is a plan sectional view showing a second embodiment of the present invention.

FIG. 4 is a plan sectional view showing a third embodiment of the present invention. .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material supply pipe 2 Raw material distributor 3 Raw material supply branch pipe 4 Upper burner 5 Lower burner 6 Upper burner oxidant supply pipe 7 Lower burner oxidant supply branch pipe 9 Collection char supply pipe 10 Char burner 21 Gasification part 22 Pressure vessel Reference Signs List 23 Generated gas take-out pipe 24 Molten slag 25 Slag cooling section 26 Slag discharge pipe 27 Lower burner oxidant supply pipe 28 Oxidizer distributor 31 Flow meter 32 Valve 33 Flow meter 34 Valve 51 Oxidizer nozzle 52 Coal supply nozzle 53 Char supply nozzle

Claims (4)

[Claims] 1. A plurality of coal burners for supplying a fine solid carbonaceous raw material and an oxidizing agent into a gasifier having a circular cross section are provided in upper and lower stages, and are collected from gas generated in the gasifier. In a gas-bed coal gasifier equipped with a char burner at the lower stage for supplying the char with the oxidant to the gasifier,
The burners installed in each stage are evenly distributed along the circumferential edge of the gasifier for each stage, and at least in the lower stage, each burner is configured to eject an equal amount of oxidant. A gas-bed coal gasifier characterized in that: 2. A plurality of coal burners for supplying a fine solid carbonaceous raw material and an oxidizing agent into a gasification furnace having a circular cross section are provided in upper and lower stages, and are collected from gas generated in the gasification furnace. In a gas-bed coal gasifier equipped with a char burner at the lower stage for supplying the char with the oxidant to the gasifier,
In each stage, a nozzle for supplying an oxidizing agent is evenly distributed along the circumferential edge of the gasification furnace in accordance with the coal burner or the coal burner and the char burner. A gas-bed coal gasifier, wherein an equal amount of an oxidizing agent is injected into the gasification furnace from each of a supply nozzle, the coal burner, and the char burner. 3. A fine solid carbonaceous raw material and an oxidizing agent are supplied into a gasification furnace having a circular cross section in two upper and lower stages, and char collected from gas generated in the gasification furnace is gasified. In the gas-bed coal gasifier for supplying to the lower furnace, the lower stage is provided with a plurality of nozzles for supplying an oxidizing agent, a burner for supplying a fine solid carbonaceous raw material, and a plurality of burners for supplying the char. The burners are respectively distributed evenly along the circumferential edge of the gasification furnace, and each nozzle for supplying the oxidant is configured to supply an equal amount of the oxidant. Coal gasifier. 4. The gas-bed coal gasifier according to claim 1, wherein the oxidizing agent supplied into the gasification furnace from at least a nozzle and a burner disposed at a lower stage uses a flow control means. A single oxidant supply pipe provided, an oxidant distributor arranged at the downstream end of the oxidant supply pipe, and each nozzle or burner or jetting the oxidant distributor and the oxidant into the gasification furnace. It is configured to be supplied through a plurality of oxidant supply branches that individually connect the two, and the oxidant distributor is configured to evenly distribute the inflowing oxidant to the plurality of oxidant supply branches. A gas-bed coal gasifier characterized by the following.