JP2012193246A - Method for adjusting slag form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adjusting slag form in a coal gasifier, capable of preventing the formation of blockage of the slag by a discharging system such as a slag tap-discharging hole and a slag-discharging hole without additionally installing a mechanical constitution such as a dissolution mean.SOLUTION: This method for adjusting the slag form is characterized by setting within 0.3 to 1.2 range the basicity of the composition of molten slag formed in the gasifying furnace, determined by the weight ratio of CaO to SiO.

Description

  The present invention relates to a coal gasification apparatus having a gasification furnace that partially oxidizes coal to gasify, and clogging occurs in discharging slag formed by melting ash contained in coal during coal gasification. It is the technique regarding the slag form adjustment method which prevents this.

Conventionally, as this type of coal gasifier, for example, techniques disclosed in Patent Documents 1 to 3 are known.
In the coal gasifier shown in Patent Publications 1 and 2, in the lower gasifier, oxygen or oxygen and water vapor and coal are introduced to generate gasified gas by partial oxidation, and the upper reformer Shows a system using a two-stage two-stage reactor in which coal and hydrogen are introduced into the generated gasified gas to generate gas, oil, and char by hydrothermal decomposition. And by making a reactor into two chambers and two stages in this way, the part which performs gasification of coal and the part which performs hydropyrolysis can be separated completely, and the operating conditions of each part can be set freely It becomes possible.

  Moreover, in the coal gasifier shown by patent document 3, pulverized coal and gasifying agents (oxygen-containing gas etc.) are injected in the gasification furnace pressurized at high temperature, and are partially oxidized in an internal gasification part. Thus, the product gas is obtained.

JP 2008-174583 A Japanese Patent Laid-Open No. 2005-162896 JP 11-140464 A

By the way, in the coal gasifier shown by the said patent documents 1-3, the slag which generate | occur | produced in the gasification furnace is located in the water tank (granulation part) located below via the slag tap discharge hole of this gasification furnace. The slag lock hopper is further guided to the lower slag lock hopper through the slag discharge hole of the water tank. At this time, the discharge system such as the slag tap discharge hole and the slag discharge hole is blocked by the discharged slag. Sometimes.
For this reason, in Patent Document 3, clogging elimination means such as a gas injection line and a cooling water extraction line are separately provided. However, the provision of such elimination means complicates the entire apparatus. Moreover, if such a cancellation | release means is operated, the pressure and temperature in a gasification furnace will be disturb | confused, and there also existed a problem of causing trouble in coal gasification processing.

  The present invention has been made in view of the above-described circumstances, and clogging of slag occurs in a discharge system such as a slag tap discharge hole and a slag discharge hole without additionally providing a mechanical configuration such as a solution means. The present invention provides a method for adjusting the slag form in a coal gasifier capable of preventing the occurrence.

In order to solve the above problems, the present invention proposes the following means.
Claim 1 of this application is a coal gasification apparatus having a gasification furnace that partially gasifies and gasifies coal, and is a method for adjusting the slag form of the molten slag formed in the gasification furnace, The composition is characterized in that the basicity determined by the weight ratio of CaO and SiO ₂ is set in the range of 0.3 to 1.2.

According to this invention, by setting the composition of the molten slag formed in the gasification furnace within the range of the basicity within the range of 0.3 to 1.2, the melting point of the slag is increased and the operation efficiency is decreased. If not invited, the generation rate of fibrous slag that can cause slag clogging can be reduced, thereby preventing slag clogging in the discharge system that discharges molten slag out of the furnace. be able to. Further, in the present invention, by setting the composition of the molten slag within the range of the basicity within a range of 0.3 to 1.2, it is possible to provide a mechanical structure such as a solution means as in the conventional case. , Slag clogging can be effectively prevented.
That is, if the basicity is less than 0.3, it is difficult to reduce the generation rate of fibrous slag, and if the basicity is greater than 1.2, the melting point of the slag increases and the operating efficiency decreases. There is a risk.

  Claim 2 of this application adjusts the raw coal used as the raw material of the said coal, and the component of the preparation agent, in order to set the basicity of the said molten slag in the range of 0.3-1.2. And

  According to this invention, in order to set the basicity of molten slag within the range of 0.3 to 1.2, by adjusting the raw coal used as the raw material of coal and the components of the preparation agent, fibrous slag Therefore, slag clogging can be effectively prevented without additionally providing a mechanical structure such as a solution means as in the prior art.

  According to the slag form adjustment method according to claim 1 of the present application, the melting point of the slag is set by setting the composition of the molten slag formed in the gasification furnace within the range of the basicity within a range of 0.3 to 1.2. As a result, the generation rate of fibrous slag can be reduced within a range that does not lead to a decrease in operating efficiency, thereby causing slag clogging in the discharge system that discharges molten slag out of the furnace. Can be prevented. Further, in the present invention, by setting the composition of the molten slag within the range of the basicity within a range of 0.3 to 1.2, it is possible to provide a mechanical structure such as a solution means as in the conventional case. , Slag clogging can be effectively prevented.

  According to the slag form adjusting method according to claim 2 of the present application, in order to set the basicity of the molten slag within the range of 0.3 to 1.2, the raw coal as a raw material of coal and the components of the preparation agent thereof By adjusting the slag, the slag clogging can be prevented by reducing the fibrous slag, so that the slag clogging can be effectively prevented without additionally providing a mechanical configuration such as a solving means as in the prior art.

It is a schematic block diagram of the coal gasifier to which this invention is applied. It is a graph which shows the basicity of molten slag, and the generation | occurrence | production ratio of fibrous slag. It is a figure for demonstrating the fibrous slag which shows a molten slag form. It is a graph which shows the relationship between the basicity of molten slag, and melting | fusing point of slag.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a general coal gasifier 100 shown as the present embodiment, which transports pulverized coal (coal) from a line (not shown) and uses a line 1 to form a gasifying agent (oxygen-containing gas or the like). ) Is injected into a pressurized gasification furnace 3 having a temperature higher than that of the burner 2 to be partially oxidized, and the generated gas G generated in the gasification furnace 3 is discharged from the upper opening 3A.
Above the upper opening 3A of the gasification furnace 3, hydrogen is introduced into the gasification gas generated in the gasification furnace 3, and gas, oil, and char are generated by hydrogenation pyrolysis (not shown). A reforming furnace is connected continuously.

Further, along with the partial oxidation in the gasification furnace 3, the ash content in the coal becomes a slag as a by-product and is slag-coated on the inner wall of the gasification furnace 3 (indicated by a symbol S), and a part of the molten slag S1 Will be discharged.
That is, the gasification furnace 3 is for discharging and dropping molten slag S1 formed therein via a slag tap discharge hole 3B provided in a lower portion thereof, and from the slag tap discharge hole 3B. The discharged molten slag S <b> 1 is cooled while dropping the slag cooling unit 4, and then stored in the slag granulating unit 5.
The slag water granulating unit 5 stores slag cooling water 6 therein, and after the molten slag S1 is granulated and rapidly cooled to form the granulated slag S2, it is discharged from the lower slag discharge hole 5A. .
In addition, the temperature in the gasification furnace 3 is about 1300-1600 degreeC, for example, the temperature of the slag cooling part 4 is about 500-800 degreeC, for example, and the temperature of the slag granulation part 5 is about about, for example It is about 40-60 degreeC.

A connecting pipe 8 having a valve 7 is connected to the slag discharge hole 5A located at the lower part of the slag water granulating unit 5, and the granulated slag S2 discharged from the slag granulating unit 5 through the connecting pipe 8. Is sent to the slag lock hopper 10.
The slag lock hopper 10 stores, for example, the granulated slag S2 for a certain period of time and causes the slag to settle. After a certain period of time has elapsed, the granulated slag S2 passes through the connecting pipe 12 having the valve 11. Is taken out of the system.

Next, the molten slag S1 generated in the gasification furnace 3 will be described.
The composition of the molten slag S1 according to the present invention is such that the basicity is set within a range of 0.3 to 1.2, and by such a basicity range setting, the cause of clogging during slag discharge The generation | occurrence | production of the fibrous slag which becomes is suppressed, and the stable discharge | emission state of slag is maintained.
And in order to set the basicity of such molten slag S1 in the range of 0.3-1.2, the raw coal used as the raw material of coal, and the component of the preparation agent are used on the basis of the basicity concerned. adjust. Here, the terms basicity say, a weight ratio of CaO and _{SiO 2 (= SiO 2 / CaO} ), as basicity of the molten slag S1 is made within the range of 0.3 to 1.2 Adjust ingredients of raw coal and its preparation. That is, the basicity of the molten slag S1 has a correlation with the basicity of the coal, and a verification test or the like is performed in advance and the correlation is known, so that the molten slag S1 is based on the basicity of the coal. It is possible to adjust the basicity.

  One reason for setting the basicity within the range of 0.3 to 1.2 is to set the basicity to 1.2 or less so that the melting point of the slag does not increase and the operating efficiency does not decrease. is there. That is, as shown in FIG. 4, when the basicity is greater than 1.2, the melting point of the slag rises rapidly, which may lead to a decrease in operating efficiency.

  Further, as another reason for setting the basicity within the range of 0.3 to 1.2, as shown in FIG. 2, by increasing the basicity, the molten slag S1 discharged from the slag tap discharge hole 3B. This is because the generation rate of “fibrous slag” contained in (dripping slag) is reduced, and in order to reduce the generation rate of fibrous slag that can cause clogging to 80% or less, the basicity is set to 0. .3 or more. That is, it has been confirmed by experiments of the present inventors that slag clogging is likely to occur when the generation rate of fibrous slag is greater than 80%. As shown in FIG. 2, when the basicity is 0.5 or more, the generation rate of fibrous slag is 20% or less.

Here, the molten slag S1 is discharged from the slag tap discharge hole 3B of the gasification furnace 3 and dropped into the slag cooling part 4, and the slag is vitrified and crystallized. The basicity and cooling rate of slag are related to crystallization and crystallization. In particular, as in the coal gasifier 100 shown in the present embodiment, slag is discharged from the gasification furnace 3 to the slag cooling unit 4 and the slag is rapidly cooled from the molten state (set to a range where the cooling rate is high). In this case, it has been confirmed by experiments of the present inventors that the influence of basicity is large, and it is possible to control the form of the slag by adjusting the basicity of the molten slag S1.
For this reason, in order to adjust the basicity of the molten slag S1, the components of the raw coal and its preparation agent are adjusted, and thereby dripping slag (molten slag) that becomes difficult to discharge from the gasification furnace 3 of the coal gasifier 100 The formation of fibrous slag in S1) is suppressed, and the coal gasifier 100 can be stably operated.

  Further, the fibrous slag shown in the present embodiment is a long body having a substantially circular cross-sectional shape (that is, a cylindrical shape), and as shown in FIG. 3, a slag having a cylindrical diameter of 0.5 mm or less is used. The “fibrous slag” described in the present embodiment. The fibrous slag has a lower sedimentation rate in water as the diameter decreases, and the discharge system is likely to be clogged. Table 1 shows the relationship between the diameter of the fibrous slag and the sedimentation speed.

  The increase / decrease in the diameter of the fibrous slag corresponds to the Reynolds number Re when the fibrous slag falls in water, but when the Reynolds number Re is less than 100, the resistance of the fibrous slag The coefficient Cd shows an increasing tendency with a constant slope as the Reynolds number Re decreases. When the fibrous slag falls in water, the diameter of 0.5 mm corresponds to “Re = 100”.

  On the other hand, as the basicity increases, the fibrous slag decreases and the fibrous slag becomes finer, and changes to “granular slag” as shown in FIG. Thereby, the flow of the molten slag S1 in the slag tap discharge hole 3B is improved, and slag clogging is reliably prevented.

  Here, the basicity adjustment procedure for setting the basicity of the molten slag S1 within the range of 0.3 to 1.2 will be described.

(1) The raw coal ash composition and ash content are measured in advance. At this time, for example, SiO ₂ , CaO, Fe ₂ O ₃ , Al ₂ O ₃ , MnO, MgO, TiO ₂ , P ₂ O ₅ , SO ₃ , K ₂ O, and Na ₂ O are measured as the ash composition of raw coal. The remainder is assumed to be loss on ignition (ig. Loss).

(2) Next, a preparation agent is prepared based on the measurement results described above and the basicity (0.3 to 1.2) of the target slag composition. Here, as the raw material of the preparation agent, for example, minerals (limestone, cinnabar, phyllite, etc.), oxide powders (blast furnace slag powder, refractory powder, various cement powders, etc.) can be used. The slag composition can be calculated, for example, by a weighted average of each ash composition and oxide composition. At this time, 2 to 5 types of representative compositions having a large weight ratio may be selected and judged.

(3) Finally, the raw coal and the preparation agent are mixed. For example, when the raw coal is conveyed while being measured on a conveyor scale or the like, the preparation agent is mixed at a constant weight ratio in accordance with the flow rate per hour (kg / h). Thereafter, the raw coal and the preparation agent are well mixed using a solid mixer, an air current conveyance or the like.

〔Example〕
Below, an example of the slag form adjustment method which concerns on this embodiment is shown.
First, the raw coal used here is Tanitoharum coal, and its ash composition and ash content are, for example, 51.05 wt% for SiO ₂ , 6.87 wt% for CaO, 10.95 wt% for Fe ₂ O ₃ , Al ₂ O ₃ 25.07 wt%, MnO 0.05 wt%, MgO 2.48 wt%, TiO ₂ 1.13 wt%, P ₂ O ₅ 0.33 wt%, SO ₃ 0.09 wt%, K ₂ O is 1.28 wt%, Na ₂ O is 0.62 wt%, and ig. Loss is 0.08 wt% (all are DRY).
In this example, the basicity of the raw coal is about 0.135. Then, the coal gasification furnace was charged with 500 kg / h of partially oxidized coal, 315 Nm ³ / h of oxygen, 50 kg / h of steam, 150 kg / h of reformed coal, and operated at a pressure of 2.5 MPaG and a temperature of 1550 ° C. The gas generation amount was about 1440 Nm ³ / h and char 60 kg / h. When raw coal was used, the amount of slag generation was about 35 kg / h, most of which was fibrous slag. .
When the basicity of the molten slag S1 is increased by gradually increasing the preparation agent relative to the raw coal, as shown in FIG. 2, the weight ratio of the fibrous slag in the molten slag S1 It was confirmed that it decreased with increasing. In particular, when the basicity of the molten slag S1 exceeds 0.3, the weight ratio of the fibrous slag in the molten slag S1 becomes 80% or less, and the slag tap discharge hole 3B and the further downstream slag discharge hole 5A. It has been confirmed that slag clogging can be prevented.

  As explained in detail above, according to the slag form adjusting method in the coal gasifier 100 according to the present embodiment, the basicity of the composition of the molten slag S1 formed in the gasification furnace 3 is 0.3 to 1.. By setting it within the range of 2, the generation rate of fibrous slag can be reduced, and thereby the molten slag S1 and the granulated slag S2 formed thereafter are discharged from the furnace to discharge the slag. It is possible to prevent clogging from occurring. Further, in the present embodiment, by setting the composition of the molten slag S1 within a range of the basicity within a range of 0.3 to 1.2, a mechanical configuration such as a solving means is additionally provided as in the related art. Therefore, slag clogging can be effectively prevented.

  In addition, in the said embodiment, in order to reduce the generation | occurrence | production ratio of fibrous slag, it is essential to set basicity in the range of 0.3-1.2, but the raise of melting | fusing point of slag is carried out. In order to suppress it, basicity may be set in the range of 0.3 to 0.5, particularly in the range of 0.3 to 1.2. And the fiber slag generation | occurrence | production ratio can be maintained at 20 to 80% by the basicity setting in the range of 0.3-0.5.

  Moreover, in the said embodiment, although the two-chamber two-stage furnace which consists of the gasification furnace 3 and a reforming furnace was used, it is not limited to this, For example, in one furnace, gasification gas is produced | generated, and hydropyrolysis In a coal gasifier having a gasification furnace that performs both of the above, the basicity of the molten slag may be adjusted within the range of 0.3 to 1.2 in order to suppress the generation of fibrous slag.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  The present invention relates to a slag form adjusting method in a coal gasification apparatus having a gasification furnace that partially oxidizes and gasifies coal.

3 Gasification furnace 3B Slag tap discharge hole 100 Coal gasifier S1 Molten slag

Claims (2)

In a coal gasification apparatus having a gasification furnace that partially oxidizes coal to gasify, a method for adjusting the slag form of molten slag formed in the gasification furnace,
The composition of the molten slag is characterized in that the basicity determined by the weight ratio of CaO and SiO ₂ is set within a range of 0.3 to 1.2.   The raw coal used as the raw material of the coal and components of the preparation agent thereof are adjusted in order to set the basicity of the molten slag within a range of 0.3 to 1.2. Slag form adjustment method.

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